To our path towards green economy, Hydrogen is often regarded to have a potential growth in the
coming future. However, the high cost of operation of fuel cell has often been a setback. If we could make use of
hydrogen gas as a fuel directly, the scope of development broadens. Owing to these aspects, this work primarily
focuses on the simulation technique of an Internal Combustion Spark Ignition Engine powered by Hydrogen gas.
The simulations of various stages have been carried out using the discrete approach, thereby investigating the
pressures and temperatures at various instants in the cycle. For the relative performance discussion we have
simulated the different cycles as ideal cycle, air fuel cycle and actual cycle. The resultant cyclic graph indicates
various discrepancies between ideal, air fuel and actual cycle. This analysis serves as a tool for a better
understanding of the variables involved and helps in optimizing engine design and fixing of various parameters,
including the determination of valve timings. Besides this, backfire, is the commonly faced problem with the
hydrogen engines. To reduce this effect, a fuel injectoris used for adding the gaseous fuel to the combustion
chamber.
Use of Nanofluids to increase the efficiency of solar panelsvarungoyal98
Experimental Investigation of the potentiality of Nanofluid in enhancing the performance of Hybrid PV/T systems. The global need for energy savings requires the usage of renewable sources in many applications. Harnessing solar energy using photovoltaic cells which converts solar radiation into electricity seems a good alternative to fossil fuels. However the heat trapped in photovoltaic cells during operation decreases the efficiency of the system. To avoid the temperature increase of the PV system we use photovoltaic-thermal hybrid solar system (Hybrid PV/T) where the unfavourable absorbed heat from the cells is collected through an additional thermal unit. Nanofluids are engineered colloidal suspensions of nanoparticles in a base fluid. Generally, the nanofluids possess greater heat transfer characteristics compared to the common fluids.
This document discusses the thermal design of a simple boiler. It presents the calculation procedures for boiler design, focusing on heat transfer modes, heat and mass balances, and a worked example. The key points are:
- Heat transfer in boilers occurs via conduction, convection, and radiation. Conduction is not considered in simple calculations.
- Heat and mass balance equations relate the heat input from fuel to the heat output via steam as well as accounting for air and flue gas flows.
- A worked example calculates furnace conditions like flue gas temperature for a methane-fueled boiler, assuming radiation is the only heat transfer mode in the furnace. Tube bank calculations then determine the exit gas
A QUICK ESTIMATION METHOD TO DETERMINE HOT RECYCLE REQUIREMENTS FOR CENTRIFUG...Vijay Sarathy
Turbomachinery Engineers often conduct studies to determine if a hot gas bypass is required for a given centrifugal compressor system. This would mean building a process model and simulating it for Emergency Shutdown conditions (ESD) & Normal Shutdown conditions (NSD) to check if the compressor operating point crosses the surge limit line (SLL). A quick estimation method that uses dimensionless number called the inertia number can be used to check prior to the study, if a Hot gas bypass (a.k.a. Hot Recycle) is required in addition to an Anti-surge line (ASV or a.k.a Cold Recycle).
The document describes a dynamic Otto cycle analysis that models the performance of spark ignition internal combustion engines. It makes three modifications to the static air-standard Otto cycle analysis: 1) using representative specific heats and heat ratios for each process, 2) relating heat release during combustion to engine parameters, and 3) including an equation for volumetric efficiency as a function of engine speed. This dynamic analysis predicts engine power and torque curves with reasonable accuracy by modeling the mass of air and temperatures at each state as engine speed varies. Sample results are shown for a Nissan Maxima engine that agree well with manufacturer specifications.
PERFORMANCE ANALYSIS OF A COMBINED CYCLE GAS TURBINE UNDER VARYING OPERATING ...meijjournal
The combined cycle gas turbine integrates the Brayton cycle as topping cycle and the steam turbine
Rankine cycle as bottoming cycle in order to achieve higher thermal efficiency and proper utilization of
energy by minimizing the energy loss to a minimum. In this work, the effect of various operating
parameters such as maximum temperature and pressure of Rankine cycle, turbine inlet temperature and
pressure ratio of Brayton cycle on the net output work and thermal efficiency of the combine cycle are
investigated. The outcome of this work can be utilized in order to facilitate the design of a combined cycle
with higher efficiency and output work. A MATLAB simulation has been carried out to study the effects and
influences of the above mentioned parameters on the efficiency and work output.
This document provides a summary of a presentation about turbomachines. It discusses the classification of turbomachines as either compressible or incompressible fluid machines that either transfer energy from or to a fluid using a rotating shaft. It also describes the components of turbomachines like compressors, turbines, bearings and systems used. The document discusses off-design and on-design analysis of turbomachines using the Euler turbine equation and the energy transfer between the rotor and fluid.
The document experimentally investigates the performance, emissions, and combustion of a diesel engine operating in CNG-diesel dual fuel mode with varying CNG injection rates and operating pressures. Tests were conducted at 6 LPM and 13.5 LPM of CNG injected at diesel injection pressures of 200, 220, and 240 bar. Results show brake thermal efficiency increased with higher pressure but decreased with more CNG, while emissions varied with both factors. CO2 and NOx increased at 220 bar then decreased at 240 bar for all fuels, while CO and UHC decreased with higher pressure and more CNG substitution. Peak heat release rate was highest for pure diesel at 240 bar due to better atomization.
Use of Nanofluids to increase the efficiency of solar panelsvarungoyal98
Experimental Investigation of the potentiality of Nanofluid in enhancing the performance of Hybrid PV/T systems. The global need for energy savings requires the usage of renewable sources in many applications. Harnessing solar energy using photovoltaic cells which converts solar radiation into electricity seems a good alternative to fossil fuels. However the heat trapped in photovoltaic cells during operation decreases the efficiency of the system. To avoid the temperature increase of the PV system we use photovoltaic-thermal hybrid solar system (Hybrid PV/T) where the unfavourable absorbed heat from the cells is collected through an additional thermal unit. Nanofluids are engineered colloidal suspensions of nanoparticles in a base fluid. Generally, the nanofluids possess greater heat transfer characteristics compared to the common fluids.
This document discusses the thermal design of a simple boiler. It presents the calculation procedures for boiler design, focusing on heat transfer modes, heat and mass balances, and a worked example. The key points are:
- Heat transfer in boilers occurs via conduction, convection, and radiation. Conduction is not considered in simple calculations.
- Heat and mass balance equations relate the heat input from fuel to the heat output via steam as well as accounting for air and flue gas flows.
- A worked example calculates furnace conditions like flue gas temperature for a methane-fueled boiler, assuming radiation is the only heat transfer mode in the furnace. Tube bank calculations then determine the exit gas
A QUICK ESTIMATION METHOD TO DETERMINE HOT RECYCLE REQUIREMENTS FOR CENTRIFUG...Vijay Sarathy
Turbomachinery Engineers often conduct studies to determine if a hot gas bypass is required for a given centrifugal compressor system. This would mean building a process model and simulating it for Emergency Shutdown conditions (ESD) & Normal Shutdown conditions (NSD) to check if the compressor operating point crosses the surge limit line (SLL). A quick estimation method that uses dimensionless number called the inertia number can be used to check prior to the study, if a Hot gas bypass (a.k.a. Hot Recycle) is required in addition to an Anti-surge line (ASV or a.k.a Cold Recycle).
The document describes a dynamic Otto cycle analysis that models the performance of spark ignition internal combustion engines. It makes three modifications to the static air-standard Otto cycle analysis: 1) using representative specific heats and heat ratios for each process, 2) relating heat release during combustion to engine parameters, and 3) including an equation for volumetric efficiency as a function of engine speed. This dynamic analysis predicts engine power and torque curves with reasonable accuracy by modeling the mass of air and temperatures at each state as engine speed varies. Sample results are shown for a Nissan Maxima engine that agree well with manufacturer specifications.
PERFORMANCE ANALYSIS OF A COMBINED CYCLE GAS TURBINE UNDER VARYING OPERATING ...meijjournal
The combined cycle gas turbine integrates the Brayton cycle as topping cycle and the steam turbine
Rankine cycle as bottoming cycle in order to achieve higher thermal efficiency and proper utilization of
energy by minimizing the energy loss to a minimum. In this work, the effect of various operating
parameters such as maximum temperature and pressure of Rankine cycle, turbine inlet temperature and
pressure ratio of Brayton cycle on the net output work and thermal efficiency of the combine cycle are
investigated. The outcome of this work can be utilized in order to facilitate the design of a combined cycle
with higher efficiency and output work. A MATLAB simulation has been carried out to study the effects and
influences of the above mentioned parameters on the efficiency and work output.
This document provides a summary of a presentation about turbomachines. It discusses the classification of turbomachines as either compressible or incompressible fluid machines that either transfer energy from or to a fluid using a rotating shaft. It also describes the components of turbomachines like compressors, turbines, bearings and systems used. The document discusses off-design and on-design analysis of turbomachines using the Euler turbine equation and the energy transfer between the rotor and fluid.
The document experimentally investigates the performance, emissions, and combustion of a diesel engine operating in CNG-diesel dual fuel mode with varying CNG injection rates and operating pressures. Tests were conducted at 6 LPM and 13.5 LPM of CNG injected at diesel injection pressures of 200, 220, and 240 bar. Results show brake thermal efficiency increased with higher pressure but decreased with more CNG, while emissions varied with both factors. CO2 and NOx increased at 220 bar then decreased at 240 bar for all fuels, while CO and UHC decreased with higher pressure and more CNG substitution. Peak heat release rate was highest for pure diesel at 240 bar due to better atomization.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
OPTIMIZATION OF AN OPEN CYCLE GAS TURBINE POWER PLANT USING EXERGOECONOMICSijmech
The purpose of current study is to analyze the performance of an open cycle gas turbine power plant using
the concepts of exergoeconomics. Exergoeconomic technique involves the use of Second law of
thermodynamics and assigns monetary values to the thermodynamic quantity known as exergy. Analyses
based on exergoeconomic criteria are done for the open cycle gas turbine power plant turbine. The
methodology is illustrated using the example of a 25 MW open cycle gas turbine power plant. Optimization
has been done for the open cycle gas turbine power plant as tradeoffs between the unit product cost of the
compressor and combustion chamber as functions of compressor pressure ratio and unit product costs of
combustion chamber and gas turbine as functions of turbine inlet temperature.
The document provides the engineering problem definition, requirements, and analysis for designing a turbojet engine. It defines the operating conditions, constraints, and performance parameters to analyze. An engineering analysis is then presented using MATLAB code to calculate temperatures, pressures, mass flows, and other parameters across the engine for a range of compressor pressure ratios from 2 to 40. Graphs of key parameters like thrust, temperatures, mass flow, and efficiency are plotted to identify the highest performing compressor pressure ratio design.
The document presents a preliminary design of a turbofan engine aimed at achieving over 25,000 N of thrust with a thrust specific fuel consumption of less than 0.025 kg/s/kN. A MATLAB code was used to generate carpet plots of specific thrust and thrust specific fuel consumption for different bypass ratios, compressor pressure ratios, and bypass pressure ratios. The final optimal design parameters chosen were: a turbine inlet temperature of 1300 K, compressor pressure ratio of 30, bypass ratio of 6, bypass pressure ratio of 1.35, inlet diameter of 0.738 m, thrust of 25,050.9 N, and thrust specific fuel consumption of 0.0187 in order to meet mission requirements with high fuel efficiency.
Chemical Process Calculations – Short TutorialVijay Sarathy
Often engineers are tasked with communicating equipment specifications with suppliers, where process data needs to be exchanged for engineering quotations & orders. Any dearth of data would need to be computed for which process related queries are sometimes sent back to the process engineer’s desk for the requested data.
The following tutorial is a refresher for non-process engineers such as project engineers, Piping, Instrumentation, Static & Rotating Equipment engineers to conduct basic process calculations related to estimation of mass %, volume %, mass flow, actual & standard volumetric flow, gas density, parts per million (ppm) by weight & by volume.
This document discusses various thermodynamic diagrams used for boiler calculations, including:
- Temperature-heat (T-Q) diagrams which show the heat transfer characteristics of heat exchangers and boiler components.
- Temperature-entropy (T-s) diagrams which represent the phases of steam/water and can display steam processes.
- Pressure-enthalpy (p-h) diagrams which make it easy to visualize the heat load shares on different boiler surfaces.
- Enthalpy-entropy (Mollier) diagrams which allow determining steam properties from two known parameters like pressure and temperature.
These diagrams provide useful visualization tools for designing and analyzing boiler performance and steam processes.
The document analyzes the impact of high ambient temperatures on the performance of gas turbine power plants in tropical climate zones. It presents a mathematical model to study the effect of ambient temperature on a gas turbine plant in northern Saudi Arabia. The model shows about a 20% reduction in power output when temperatures rise from the design condition of 15°C to actual summer highs of 50°C. The document then evaluates the economic justification for adding an absorption chiller to the plant to recover lost power, finding the payback period would be 1.14 years or less. It recommends gas turbines with inlet air cooling for future plants in hot climates.
This document summarizes an article from the International Journal of Mechanical Engineering and Technology. It describes the development of a mathematical and simulation model to analyze the effects of engine design parameters on the performance and emissions of spark ignition engines. The model can be used to simulate engine operation and assist with engine design. It examines three engine designs (under square, square, and over square) running on gasoline, LPG, and CNG. The model calculates output power, efficiency, fuel consumption, ignition delay, exhaust temperature, heat loss, and exhaust emissions for each design/fuel combination. It found square engines (stroke/diameter ratio of 1) to be the most efficient and suitable design overall.
1. Gasoline engines burn gasoline through spark ignition, while diesel engines burn diesel oil through compression ignition without a spark plug.
2. The ideal air-fuel ratio for complete combustion is around 14.7:1 by weight. A leaner mixture improves fuel economy and reduces emissions while a richer mixture improves power and cold starting but hurts fuel efficiency and increases emissions.
3. Brake power is the engine's power measured at the crankshaft and indicates net output, while indicated power includes all engine work but not mechanical losses like friction. Mechanical efficiency is the ratio of brake to indicated power.
The document describes four thermodynamic cycles: Otto, Diesel, Dual, and air-standard cycles. It provides equations for calculating work, heat transfer, and efficiency for each cycle. It explains that the Dual cycle generalizes the Otto and Diesel cycles by allowing both constant volume and constant pressure heat addition. It also notes that the Diesel cycle has lower efficiency than the Otto cycle at the same compression ratio but is used in combustion engines because it requires higher compression to ignite fuel.
Design and Thermal Analysis of Hydraulic Oil Cooler by using Computational Fl...IRJET Journal
This document describes a study analyzing the thermal performance of a hydraulic oil cooler using computational fluid dynamics (CFD). It involves:
1) Designing a hydraulic oil cooler with cross-flow heat exchanger cores to transfer heat from hot hydraulic oil into ambient air.
2) Developing a thermal model and equations to calculate heat transfer rates, oil/air temperatures, heat transfer coefficients, and surface area required.
3) Validating the model through experimental testing of an oil cooler setup and comparing predicted vs actual temperature values.
This document outlines an assignment for students to evaluate the performance of a 4-stroke petrol engine. It discusses key performance parameters like power, efficiency, fuel consumption, emissions. The objective is for students to understand how to calculate speed, fuel use, air use, and evaluate exhaust smoke and emissions in order to optimize engine performance. Parameters like power, efficiency, emissions are defined and methods to test them such as using a dynamometer are described.
This document describes the design and analysis of an air-cooled radiator for a diesel engine with a hydrostatic transmission in a special purpose vehicle. It involves calculating the heat loads of the engine and transmission, designing a customized radiator using CAD software to dissipate the heat within given space constraints, and analyzing the radiator design using CFD software. The radiator is designed to have a heat transfer area of 1.23 square meters and incorporates fins to increase surface area for improved heat dissipation performance within the allotted volume of 706mm width, 370mm height and 80mm depth.
1 ijebm jan-2018-1-combustion adjustment in a naturalAI Publications
Shortage of detailed and accurate experimental data on fuel-air mixing in furnaces is due to the difficulty and complexity of measurements in flames. Although it may be possible with infra-Red camera to obtain an indication of what happens in the furnace by graphical image resolution this is not expected to be sufficiently detailed because it contains only the temperature gradient. More detailed information, however, may be obtained from the simulated resolution using Computational Fluid Dynamics (CFD) technique where the total number of elements/points defines the detailed level that can be displayed or captured in graphical image. Simulation resolution studies two aspects of the momentum effects on flame which are the forward momentum normally associated with the average outlet velocity of the combustion products and the lateral momentum caused by swirl. Following the American Petroleum Institute guidelines (API 560) for combustion adjustment in furnaces, it may be possible to have less emission and a maximum efficiency, but the potential interaction between the several operation and design factors are not thereby considered as in a mathematical model of CFD.
This document discusses heat exchangers, Rankine and Brayton cycles, combined cycles, cogeneration cycles, and provides examples of calculations for a Rankine cycle. It defines open and closed heat exchangers, explains how Rankine and Brayton cycles have the same processes but different T-s diagrams due to different working fluids, describes combined and cogeneration cycles which improve efficiency, and shows calculations for heat supplied, efficiencies, work, and conclusions for a sample Rankine cycle problem.
This document discusses various criteria and comparisons of internal combustion engines, including:
1) Indicator power, brake power, friction power, thermal efficiency, specific fuel consumption, indicator mean effective pressure, torque, and volumetric efficiency are analyzed.
2) Graphs show relationships between torque and speed, brake power and indicated power vs speed, and mechanical efficiency vs speed and brake power.
3) Fuel consumption varies with engine speed, with laws enacted to require better vehicle fuel efficiency and decrease air pollution from depletion of fossil fuels.
Pinch analysis technique to optimize heat exchangerK Vivek Varkey
This document summarizes a student project applying pinch analysis to optimize the heat exchanger network (HEN) for a CFU unit at an ONGC Hazira plant. The student calculated heat duties for 5 heat exchangers and determined the minimum hot and cold utility requirements. By drawing temperature interval diagrams, the student designed an optimized HEN that couples process streams to maximize heat exchange and minimize utility needs. The optimized design was found to reduce heating utility needs by 83.4% and cooling needs by 33.8% compared to the current design.
The mean key variable to control the burner performance for safe and efficient operations is the amount of excess air or oxygen which flow to react with fuel. In accordance with Typical Draft Profile in a Natural Draft furnace the numerical results of computing fluid dynamics model of the air flow from the environment to the burner by adjusting the area of air box prototype openings will give the necessary information to adjust the performance of burner as optimum. The model of air box prototype is useful tool in applying similarity theory on another burners̕ designs which depends the air box tools to calibrate the quantity of combustion air flow to the burner.
Design With Solid works Software and Planning Calculation Analysis of Fire Tu...IJRES Journal
Steam boilers (boilers) is a closed vessel made of steel that is used to generate steam. In the modern era many industries such as household scale industries for the manufacture of oyster mushroom spawn to use aid as a supplier of steam boilers are used as a sterilization process baglog. Annually, the number of requests oyster mushroom spawn have been increases, so the boiler is very significant equipment to increase the number of baglog production as oyster mushroom growing media.To help to fulfill the small industryrequiremets for oyster mushroom nursery,plannedatype offire tubeboilerthatcanhelpthe availability ofsteam ina lowscalewithsteamoutputcapacity of70kg/ h, temperature120℃, pressure1.5barandusingmaterialsLPGfuelas a source ofheatenergy.From the results of this design, fire tube boiler have efficiency of 0.934 % . The kettle body is made from asphalt drums pertamina with the Cold Rolled Steel materials. Used asphalt drums because of its availability in the market more easier to obtained easily and the dimensions of asphalt drum capable of holding for temperature and pressure have been determined . As for the pipe material using Carbon Steel Tubing Boilers ASME SA - 178A GRADE A / SA - 214 (Plain Carbon).
Hydrogen (H2) is the simplest and lightest element. It is the most abundant element in the universe but does not occur naturally on Earth. The main methods to produce hydrogen are steam reforming of hydrocarbons like methane, which produces 90% of hydrogen, and electrolysis of water, which produces 6%. Hydrogen has many uses including heating, electricity, fertilizer production, and engines, but also has challenges for safe and efficient production and storage.
The document discusses hydrogen fuel cells, which generate electricity through a chemical reaction between oxygen and an internal fuel like hydrogen. Hydrogen fuel cells are mainly used for small electronics and home power because they do not generate enough electricity for large-scale use. The technology works by taking in oxygen from the air and combining it with water to produce electricity, as long as water is available.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
OPTIMIZATION OF AN OPEN CYCLE GAS TURBINE POWER PLANT USING EXERGOECONOMICSijmech
The purpose of current study is to analyze the performance of an open cycle gas turbine power plant using
the concepts of exergoeconomics. Exergoeconomic technique involves the use of Second law of
thermodynamics and assigns monetary values to the thermodynamic quantity known as exergy. Analyses
based on exergoeconomic criteria are done for the open cycle gas turbine power plant turbine. The
methodology is illustrated using the example of a 25 MW open cycle gas turbine power plant. Optimization
has been done for the open cycle gas turbine power plant as tradeoffs between the unit product cost of the
compressor and combustion chamber as functions of compressor pressure ratio and unit product costs of
combustion chamber and gas turbine as functions of turbine inlet temperature.
The document provides the engineering problem definition, requirements, and analysis for designing a turbojet engine. It defines the operating conditions, constraints, and performance parameters to analyze. An engineering analysis is then presented using MATLAB code to calculate temperatures, pressures, mass flows, and other parameters across the engine for a range of compressor pressure ratios from 2 to 40. Graphs of key parameters like thrust, temperatures, mass flow, and efficiency are plotted to identify the highest performing compressor pressure ratio design.
The document presents a preliminary design of a turbofan engine aimed at achieving over 25,000 N of thrust with a thrust specific fuel consumption of less than 0.025 kg/s/kN. A MATLAB code was used to generate carpet plots of specific thrust and thrust specific fuel consumption for different bypass ratios, compressor pressure ratios, and bypass pressure ratios. The final optimal design parameters chosen were: a turbine inlet temperature of 1300 K, compressor pressure ratio of 30, bypass ratio of 6, bypass pressure ratio of 1.35, inlet diameter of 0.738 m, thrust of 25,050.9 N, and thrust specific fuel consumption of 0.0187 in order to meet mission requirements with high fuel efficiency.
Chemical Process Calculations – Short TutorialVijay Sarathy
Often engineers are tasked with communicating equipment specifications with suppliers, where process data needs to be exchanged for engineering quotations & orders. Any dearth of data would need to be computed for which process related queries are sometimes sent back to the process engineer’s desk for the requested data.
The following tutorial is a refresher for non-process engineers such as project engineers, Piping, Instrumentation, Static & Rotating Equipment engineers to conduct basic process calculations related to estimation of mass %, volume %, mass flow, actual & standard volumetric flow, gas density, parts per million (ppm) by weight & by volume.
This document discusses various thermodynamic diagrams used for boiler calculations, including:
- Temperature-heat (T-Q) diagrams which show the heat transfer characteristics of heat exchangers and boiler components.
- Temperature-entropy (T-s) diagrams which represent the phases of steam/water and can display steam processes.
- Pressure-enthalpy (p-h) diagrams which make it easy to visualize the heat load shares on different boiler surfaces.
- Enthalpy-entropy (Mollier) diagrams which allow determining steam properties from two known parameters like pressure and temperature.
These diagrams provide useful visualization tools for designing and analyzing boiler performance and steam processes.
The document analyzes the impact of high ambient temperatures on the performance of gas turbine power plants in tropical climate zones. It presents a mathematical model to study the effect of ambient temperature on a gas turbine plant in northern Saudi Arabia. The model shows about a 20% reduction in power output when temperatures rise from the design condition of 15°C to actual summer highs of 50°C. The document then evaluates the economic justification for adding an absorption chiller to the plant to recover lost power, finding the payback period would be 1.14 years or less. It recommends gas turbines with inlet air cooling for future plants in hot climates.
This document summarizes an article from the International Journal of Mechanical Engineering and Technology. It describes the development of a mathematical and simulation model to analyze the effects of engine design parameters on the performance and emissions of spark ignition engines. The model can be used to simulate engine operation and assist with engine design. It examines three engine designs (under square, square, and over square) running on gasoline, LPG, and CNG. The model calculates output power, efficiency, fuel consumption, ignition delay, exhaust temperature, heat loss, and exhaust emissions for each design/fuel combination. It found square engines (stroke/diameter ratio of 1) to be the most efficient and suitable design overall.
1. Gasoline engines burn gasoline through spark ignition, while diesel engines burn diesel oil through compression ignition without a spark plug.
2. The ideal air-fuel ratio for complete combustion is around 14.7:1 by weight. A leaner mixture improves fuel economy and reduces emissions while a richer mixture improves power and cold starting but hurts fuel efficiency and increases emissions.
3. Brake power is the engine's power measured at the crankshaft and indicates net output, while indicated power includes all engine work but not mechanical losses like friction. Mechanical efficiency is the ratio of brake to indicated power.
The document describes four thermodynamic cycles: Otto, Diesel, Dual, and air-standard cycles. It provides equations for calculating work, heat transfer, and efficiency for each cycle. It explains that the Dual cycle generalizes the Otto and Diesel cycles by allowing both constant volume and constant pressure heat addition. It also notes that the Diesel cycle has lower efficiency than the Otto cycle at the same compression ratio but is used in combustion engines because it requires higher compression to ignite fuel.
Design and Thermal Analysis of Hydraulic Oil Cooler by using Computational Fl...IRJET Journal
This document describes a study analyzing the thermal performance of a hydraulic oil cooler using computational fluid dynamics (CFD). It involves:
1) Designing a hydraulic oil cooler with cross-flow heat exchanger cores to transfer heat from hot hydraulic oil into ambient air.
2) Developing a thermal model and equations to calculate heat transfer rates, oil/air temperatures, heat transfer coefficients, and surface area required.
3) Validating the model through experimental testing of an oil cooler setup and comparing predicted vs actual temperature values.
This document outlines an assignment for students to evaluate the performance of a 4-stroke petrol engine. It discusses key performance parameters like power, efficiency, fuel consumption, emissions. The objective is for students to understand how to calculate speed, fuel use, air use, and evaluate exhaust smoke and emissions in order to optimize engine performance. Parameters like power, efficiency, emissions are defined and methods to test them such as using a dynamometer are described.
This document describes the design and analysis of an air-cooled radiator for a diesel engine with a hydrostatic transmission in a special purpose vehicle. It involves calculating the heat loads of the engine and transmission, designing a customized radiator using CAD software to dissipate the heat within given space constraints, and analyzing the radiator design using CFD software. The radiator is designed to have a heat transfer area of 1.23 square meters and incorporates fins to increase surface area for improved heat dissipation performance within the allotted volume of 706mm width, 370mm height and 80mm depth.
1 ijebm jan-2018-1-combustion adjustment in a naturalAI Publications
Shortage of detailed and accurate experimental data on fuel-air mixing in furnaces is due to the difficulty and complexity of measurements in flames. Although it may be possible with infra-Red camera to obtain an indication of what happens in the furnace by graphical image resolution this is not expected to be sufficiently detailed because it contains only the temperature gradient. More detailed information, however, may be obtained from the simulated resolution using Computational Fluid Dynamics (CFD) technique where the total number of elements/points defines the detailed level that can be displayed or captured in graphical image. Simulation resolution studies two aspects of the momentum effects on flame which are the forward momentum normally associated with the average outlet velocity of the combustion products and the lateral momentum caused by swirl. Following the American Petroleum Institute guidelines (API 560) for combustion adjustment in furnaces, it may be possible to have less emission and a maximum efficiency, but the potential interaction between the several operation and design factors are not thereby considered as in a mathematical model of CFD.
This document discusses heat exchangers, Rankine and Brayton cycles, combined cycles, cogeneration cycles, and provides examples of calculations for a Rankine cycle. It defines open and closed heat exchangers, explains how Rankine and Brayton cycles have the same processes but different T-s diagrams due to different working fluids, describes combined and cogeneration cycles which improve efficiency, and shows calculations for heat supplied, efficiencies, work, and conclusions for a sample Rankine cycle problem.
This document discusses various criteria and comparisons of internal combustion engines, including:
1) Indicator power, brake power, friction power, thermal efficiency, specific fuel consumption, indicator mean effective pressure, torque, and volumetric efficiency are analyzed.
2) Graphs show relationships between torque and speed, brake power and indicated power vs speed, and mechanical efficiency vs speed and brake power.
3) Fuel consumption varies with engine speed, with laws enacted to require better vehicle fuel efficiency and decrease air pollution from depletion of fossil fuels.
Pinch analysis technique to optimize heat exchangerK Vivek Varkey
This document summarizes a student project applying pinch analysis to optimize the heat exchanger network (HEN) for a CFU unit at an ONGC Hazira plant. The student calculated heat duties for 5 heat exchangers and determined the minimum hot and cold utility requirements. By drawing temperature interval diagrams, the student designed an optimized HEN that couples process streams to maximize heat exchange and minimize utility needs. The optimized design was found to reduce heating utility needs by 83.4% and cooling needs by 33.8% compared to the current design.
The mean key variable to control the burner performance for safe and efficient operations is the amount of excess air or oxygen which flow to react with fuel. In accordance with Typical Draft Profile in a Natural Draft furnace the numerical results of computing fluid dynamics model of the air flow from the environment to the burner by adjusting the area of air box prototype openings will give the necessary information to adjust the performance of burner as optimum. The model of air box prototype is useful tool in applying similarity theory on another burners̕ designs which depends the air box tools to calibrate the quantity of combustion air flow to the burner.
Design With Solid works Software and Planning Calculation Analysis of Fire Tu...IJRES Journal
Steam boilers (boilers) is a closed vessel made of steel that is used to generate steam. In the modern era many industries such as household scale industries for the manufacture of oyster mushroom spawn to use aid as a supplier of steam boilers are used as a sterilization process baglog. Annually, the number of requests oyster mushroom spawn have been increases, so the boiler is very significant equipment to increase the number of baglog production as oyster mushroom growing media.To help to fulfill the small industryrequiremets for oyster mushroom nursery,plannedatype offire tubeboilerthatcanhelpthe availability ofsteam ina lowscalewithsteamoutputcapacity of70kg/ h, temperature120℃, pressure1.5barandusingmaterialsLPGfuelas a source ofheatenergy.From the results of this design, fire tube boiler have efficiency of 0.934 % . The kettle body is made from asphalt drums pertamina with the Cold Rolled Steel materials. Used asphalt drums because of its availability in the market more easier to obtained easily and the dimensions of asphalt drum capable of holding for temperature and pressure have been determined . As for the pipe material using Carbon Steel Tubing Boilers ASME SA - 178A GRADE A / SA - 214 (Plain Carbon).
Hydrogen (H2) is the simplest and lightest element. It is the most abundant element in the universe but does not occur naturally on Earth. The main methods to produce hydrogen are steam reforming of hydrocarbons like methane, which produces 90% of hydrogen, and electrolysis of water, which produces 6%. Hydrogen has many uses including heating, electricity, fertilizer production, and engines, but also has challenges for safe and efficient production and storage.
The document discusses hydrogen fuel cells, which generate electricity through a chemical reaction between oxygen and an internal fuel like hydrogen. Hydrogen fuel cells are mainly used for small electronics and home power because they do not generate enough electricity for large-scale use. The technology works by taking in oxygen from the air and combining it with water to produce electricity, as long as water is available.
The document discusses the history and development of wind energy. It outlines key milestones in wind energy technology from the 1st century AD to modern utility-scale wind farms. The basics of wind power generation and the components of modern wind turbines are explained. The advantages of wind such as no emissions and fuel conservation are contrasted with challenges like intermittency, bird mortality, and visual impacts. Offshore wind power is presented as the future of wind energy due to stronger and more consistent winds offshore.
Hydrogen is the most abundant element in the universe and can be used as a renewable energy. It rarely occurs naturally on Earth as H2. There are three main production methods - chemical reforming, electrolysis, and thermochemical processes. Chemical reforming, also called steam reforming, uses high temperatures to produce hydrogen. Electrolysis uses electricity to split water into hydrogen and oxygen. Thermochemical processes employ chemical reactions and heat to produce hydrogen at lower temperatures than steam reforming. Fuel cells that use hydrogen have higher efficiencies than gasoline engines and can power vehicles. Further improvements to hydrogen production and fuel cells are needed to enable widespread use.
This document analyzes a hybrid power system consisting of solar PV, wind turbines, and hydrogen fuel cells. It discusses the technical details of each component and how they work together. The solar and wind energy is used to generate hydrogen through electrolysis, which is then stored and converted back to electricity through a fuel cell. This hybrid approach provides a more reliable electricity source than any single component alone due to energy storage via hydrogen.
a presentation Hydrogen energy by MUKESH RAMMukesh Ram
Hydrogen can be used as an energy carrier but must be produced from other substances like water or fossil fuels. It is commonly extracted via electrolysis of water or steam reforming of methane. Steam reforming currently accounts for most hydrogen production but results in greenhouse gas emissions. Hydrogen fuel cells combine hydrogen and oxygen to produce electricity and water. They have potential applications to power vehicles and off-grid locations. However, widespread adoption of hydrogen energy faces challenges including high costs of production and fuel cells as well as greenhouse gas emissions associated with current production methods.
This document provides an overview of energy sources and conservation. It discusses key scientists in energy development like James Joule and the laws of thermodynamics. It also covers various energy sources like fossil fuels, nuclear power, solar energy, and biomass. Non-renewable energy sources are those that cannot be replaced quickly, like coal, petroleum and natural gas. Renewable sources include solar, wind and biomass. The document examines energy usage trends worldwide and in India. It analyzes challenges around meeting India's increasing energy demands in a sustainable manner.
Fuel cells generate electricity through an electrochemical reaction between hydrogen and oxygen, producing water and heat as byproducts. They were first demonstrated in 1801 but were invented in 1839. Fuel cells are more efficient than combustion engines and produce no pollution. A basic fuel cell system consists of a fuel cell stack that generates electricity through chemical reactions, a fuel processor that converts fuel into a form usable by the stack, a current converter that adapts the current for applications, and a heat recovery system. There are several types of fuel cells that operate at different temperatures. Fuel cells show promise for transportation, stationary power generation, and portable electronics applications due to their reliability, efficiency and lack of emissions.
1839 - Sir William Grove, first electrochemical H2/O2
reaction to generate energy
• 1950s - GE developed the solid-ion exchange H2 fuel cell
used by NASA
• 1960s- GE produced the fuel cell-based electrical power
system for NASA Gemini and Apollo space capsules
• 1960s other fuel cells discovered – phosphoric acid, SOFC,
molten carbonate
• 1970s – Vehicle manufacturers began to experiment FCEV.
• 1990 – The California Air Resource Board introduced the
Zero Emission Vehicle (ZEV) Mandate.
• 2000 – Fuel cell buses were deployed as part of the
HyFleet/CUTE project
• 2007 – fuel cell started to be sold commercially as APU
• 2008 – Honda begins leasing the FCX fuel cell electric
vehicle.
• 2009 – Large scale of residential CHP programme in Japan.
Hydrogen has the highest energy content by mass of any fuel and can be used as a substitute for hydrocarbons. It has a non-polluting burning process. There are several methods for producing hydrogen, including electrolysis of water, thermo-chemical processes, and from fossil fuels. Electrolysis uses electricity to split water into hydrogen and oxygen gases. Filter press electrolyzers are most widely used due to their ability to operate at high current densities and production rates. There are challenges to storing hydrogen including its low density and challenges maintaining it as a liquid. Storage methods include high pressure gas, liquid storage using cryogenics, underground storage, and chemically storing it in metal hydrides.
- Hydrogen can be used as a fuel in fuel cells or internal combustion engines. It is the most abundant element in the universe and can be produced from water through electrolysis using renewable energy sources.
- Hydrogen fuel cell vehicles operate by using hydrogen and oxygen to produce electricity through an electrochemical reaction without combustion, emitting only water vapor. Several automakers have developed hydrogen fuel cell vehicle prototypes.
- For widespread adoption, infrastructure is needed for large-scale hydrogen production, storage, and distribution similar to today's gas stations. Challenges include the flammability of hydrogen and high costs of production compared to fossil fuels.
This document analyzes and compares the performance of gasoline direct injection (GDI) engines to port fuel injection (PFI) engines using a two-region thermodynamic model. The analysis examines parameters such as pressure, fuel consumption, and work produced during the compression and expansion phases. Key findings include:
1) GDI engines produce considerable work compared to PFI engines, despite higher fuel consumption.
2) A two-region thermodynamic model is used that divides the cylinder volume into burned and unburned regions to model combustion.
3) The analysis finds that while GDI engines have higher fuel utilization, they still generate significant work relative to PFI engines.
Diesel Engine CFD Simulations: Investigation of Time Step on the Combustion P...IRJET Journal
This document summarizes a computational fluid dynamics (CFD) study of the effects of time step size on diesel combustion and emissions in a single cylinder research engine. The study developed a CFD model to simulate the combustion of n-heptane injected at top dead center (TDC) using ANSYS Fluent. It evaluated time steps of 5 crank angle degrees corresponding to injection durations of 0.0005 seconds. The results showed that heat transfer from the piston and cylinder head significantly affected combustion temperatures due to cooling of the fuel-air mixture.
This document summarizes the modeling, identification, and control of a 162MW heavy duty industrial gas turbine. It describes using Rowen's model and a neural network model to model the mechanical behavior and system identification of the gas turbine. The control rules are applied to both models and their results are compared. Rowen's model is a commonly used simplified model for gas turbines, while the neural network model identifies the system using input-output data. The document evaluates and compares the performance of the two models.
A Finite Element Thermo-Mechanical Stress Analysis of IC Engine PistonIRJET Journal
This document discusses a finite element analysis of thermal and mechanical stresses on an internal combustion engine piston. It begins with an introduction to pistons and the stresses they experience from high temperatures and pressures within the engine cylinder. It then describes a thermal analysis conducted using ANSYS software to model the piston's temperature distribution and calculate thermal stresses. The analysis applies thermal boundary conditions at different surfaces of the piston based on convection heat transfer calculations. The goal is to identify locations of maximum and minimum stress on the piston.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document summarizes a numerical simulation study of entropy generation in centrifugal compressors for micro-turbine applications with different exit blade angles. The study used 3D CFD simulations to analyze the flow field and quantify entropy generation from the inlet to outlet of compressors with 10-50 degree exit blade angles. The results showed entropy generation of around 60 J/kgK from the 0.1-0.6 streamwise locations where flow was parallel to the inlet, but around 480 J/kgK from 0.6-1.0 locations where deformation was high due to separation and leakage flows. Increased exit blade angle reduced entropy generation in the 0.6-1.0 locations by alleviating shear layers at the exit
(
ME- 495 Laboratory Exercise
–
Number 1
– Brayton Cycle -
ME Department, SDSU
-
Nourollahi
) (
11
)Brayton Cycle (Gas Turbine Power Cycle)
Objective
The objective of this lab exercise is to gain practical knowledge of the Brayton cycle. The Brayton cycle illustrates the cold-air-standard assumption (constant specific heats at room temperature) model of a gas turbine power cycle. A portable propulsion laboratory[footnoteRef:1] containing a Model SR-30 turbojet is used in this exercise. The student shall apply the basic equations for Brayton cycle analysis by using empirical measurements at different points in the Brayton cycle. [1: Manufactured by Turbine Technologies Ltd. Called TTL Mini-Lab]
Figure 1: TTL Mini-Lab manufactured by Turbine Technologies Ltd. (TTL)Background
A simple gas turbine engine has three main components: a compressor section, a combustion chamber and a turbine section. Basic operation entails drawing atmospheric air into the compressor where it is heated through compression. The compressed and heated air is mixed with fuel in the combustion chamber. The air/fuel mixture burns at constant pressure in the combustion chamber. The resulting hot gas is directed to the turbine section where it expands. As the gas expands it produces a thrust reaction and performs work by turning the turbine. The turbine is connected to the compressor by a shaft. The resulting shaft work is used to drive the compressor and auxiliary power supplies.
The gas turbine has wide spread application. Most notably, it is used to power and propel aircraft and large ships. In some cases only the thrust resulting from the expanding gas exiting the turbine is used for propulsion and the shaft work is used to drive the compressor and power electrical systems. In turbo-fan engines some of the shaft work is used to drive a large fan that aids in propulsion. In other applications, such as helicopters and ships, propulsion is achieved through the shaft work, which is used to drive transmission/gear boxes that are connected to the rotor blades or propeller, respectively. Gas turbines are also commonly used to drive large electrical generators in power plant applications.Theory
The Brayton cycle consists of four basic processes (see Figure3 & 4). Low-pressure air is drawn into the compressor section and undergoes isentropic compression. Next, the heated and compressed air is combined with fuel in the combustion chamber. The air/fuel mixture experiences reversible constant pressure heat addition. The resulting hot gas enters the turbine section where it undergoes isentropic expansion. To complete the cycle (the exhaust and intake in the open cycle) the gas experiences reversible constant pressure heat rejection.
Thermodynamics and the First Law of Thermodynamics determine the overall energy transfer. The following assumptions are used when analyzing the gas turbine cycles:
1. The working fluid (air) is an ideal gas throughout the cycle.
2. The combust ...
Improving the Heat Transfer Rate for Multi Cylinder Engine Piston and Piston ...IOSR Journals
The four stroke otto engine uses just one of the four strokes to perform work. This causes various
problems: The engine runs jerkily, and this can only be prevented by a large flywheel, which needs a lot of
space and weights pretty much in addition. In this thesis, thermal loads and pressures produced in the multi
cylinder petrol engine Toyota 86 Car by varying compression ratios 14:1, 15:1, 18:1, 20:1 and 25:1 are
calculated by mathematical correlations And also calculating the effect of these thermal loads on piston and
piston rings by varying materials Cast Iron, Aluminum Alloy 6061 for piston and Cast Iron and Steel for piston
rings.FEA transient thermal analysis is performed on the parametric model to validate the effect of thermal
loads on piston and piston rings for different materials. The optimum value of compression ratio and the better
material is determined by analysis results to improve the heat transfer rate of multi cylinder engine piston and
piston rings. Dynamic analysis is done on the piston by applying the pressures developed and also static
analysis by applying the maximum pressure.
Iaetsd computer simulation of compression ignition engine through matlabIaetsd Iaetsd
This document discusses a computer simulation of a compression ignition engine using MATLAB. The simulation models the engine cycle in two zones - a burned zone and unburned zone. It uses a Wiebe function to determine the mass fraction burned and calculates parameters like pressure, temperature, heat release and emissions over the engine cycle. The simulation is first validated against experimental engine test data. Sensitivity studies are then conducted by varying combustion model constants to better understand their impact on predictions and combustion mechanisms. The simulation calculates performance parameters like brake power, fuel consumption and efficiencies over the engine's operating range. It aims to provide insights into combustion and pollutant formation at different loads and injection timings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Stirling engine performance prediction using schmidt analysis by considering ...eSAT Journals
Abstract A low temperature ratio Stirling engine analysis required for cost effective, less environment harmfulness and more efficient power generation compare to Rankine cycle and Brayton cycle for this temperature ratio. A new and complete model for a Stirling engine has been established. This computerized model predicts the behavior of existing engines reasonably accurately for cases where a quantitative comparison is available. In order to obtain a closed solution suitable for design optimization a simplified model for a Stirling engine has been derived considering different types of losses in this engine. This new model has sufficient accuracy for prediction of the behavior a real engine and its results are quite close to the complete model predictions. Index Terms: Stirling Engine, Schmidt Analysis, Low temperature ratio, Engine Losses, computerized model
EXPERIMENTAL AND NUMERICAL STUDY OF A MICRO-COGENERATION STIRLING ENGINE FOR ...Denny John
The document describes an experimental and numerical analysis of a commercial Stirling engine unit capable of generating 8 kW of hot water and 1 kW of electricity using natural gas. Key points:
- An experimental campaign was conducted to collect internal and external measurements of the unit under testing at different temperatures to validate a numerical model.
- The numerical model divides the engine into five cells and simulates the thermodynamic conditions within each cell over short time steps to evaluate the engine's performance.
- The results from the experimental campaign and numerical model are compared to draw conclusions about the engine's efficiency under different operating temperatures.
Validation of Design Parameters of Radiator using Computational ToolIRJET Journal
This document discusses the validation of design parameters for automobile radiators using computational tools. It presents two case studies where the thermal performance of radiators is analyzed using the log mean temperature difference (LMTD) and number of transfer units (NTU) methods and the results are compared to those from a computational software tool (HXCombine). The results show good agreement between the manual calculations and software outputs, validating the use of computational tools for radiator design. Parameters like heat transfer rate, outlet temperatures, effectiveness and heat transfer area are compared for both case studies. This research demonstrates that computational tools can accurately analyze and design radiator performance.
CFD Analysis on the Effect of Injection Timing for Diesel Combustion and Emis...IJERA Editor
This paper describes the effect of injection timing in diesel combustion. Ansys Fluent a computational fluid dynamics tool is used to study the combustion of diesel with three different injection timing. The fuel is injected before TDC, at TDC and after TDC. The parameters such as temperature, pressure, velocity, density, soot and NOx emission are compared. The specie transport model is used for modelling the combustion. Standard k-e (2 equ) is used for modelling the turbulence. The analysis is carried out by only considering the compression and expansion strokes. The pressure reaches the maximum when the fuel is injected before TDC and the maximum temperature is when injected at TDC. The NOx emission is less when the fuel is injected at TDC and the soot formation is when fuel injected before TDC.
This document analyzes the cooling of an internal combustion (IC) engine using water cooling. It discusses key aspects of engine cooling systems including:
- IC engines reach high temperatures during combustion, so cooling is needed to avoid overheating. Water cooling and thermosyphon circulation are common cooling methods.
- Thermosyphon cooling works via natural convection as hot water rises and is replaced by cold water, circulating through the engine and radiator.
- Heat transfer equations are provided to calculate the quantity of water needed for cooling based on factors like surface area, temperature difference, and heat transfer coefficients.
- The performance of water-cooled engines is evaluated based on parameters like indicated power, mechanical
CFD Analysis of Exhaust Manifold of SI Engine and Comparison of Back Pressure...IOSRJMCE
Exhaust manifold is one of the most critical components of an IC Engine. The functioning of exhaust manifold is complex and is dependent on many parameters viz. back pressure, exhaust velocity, scavenging etc. In the present work, the performance of a four-stroke four cylinder gasoline engine exhaust manifold have been analysed using three different fuels - gasoline, alcohol, and LPG for the estimation of flow characteristics, thermal characteristics, and minimum back pressure. The manifold modelling is done in Creo2.0 followed by meshing and analysis in ANSYS. The LPG fuel gives minimum back pressure, temperature and velocity being approximately in the same range for all three fuels viz. gasoline, alcohol and LPG. Thus, LPG can be considered as a suitable alternative for gasoline in terms of minimum back flow in manifold.
This document summarizes a method for optimally scheduling gas turbine compressor washing to minimize fuel consumption and emissions. It describes a dynamic model for estimating compressor degradation over time using a Kalman filter. It then presents an economic optimization model that considers fuel and maintenance costs to determine the optimal schedule and types of compressor washes (online, offline, idle) to maximize efficiency. Simulations showed potential fuel and cost savings compared to a fixed maintenance schedule by optimizing the timing and types of washes over a one-year period.
This document summarizes a method for optimally scheduling gas turbine compressor washing to minimize fuel consumption and emissions. It describes a dynamic model for estimating compressor degradation over time using a Kalman filter. It then presents an economic optimization model that considers fuel and maintenance costs to determine the optimal schedule and types of compressor washes (online, offline, idle) to maximize efficiency. Simulations showed potential fuel and cost savings compared to a fixed maintenance schedule by optimizing the timing and types of washes over a one-year period.
This document summarizes the application of pinch technology to optimize heat integration in a crude organic distillation unit. It provides an overview of the unit's process and existing heat exchanger network. A heat and material balance is developed from available data. Pinch analysis techniques are then applied, including constructing composite curves from extracted stream data and determining minimum hot and cold utility targets. The analysis identifies opportunities to reduce utility usage through improved heat recovery and exchange network design according to pinch analysis principles.
1. The document discusses gas power cycles and ideal cycles that approximate internal combustion engines. It focuses on the Otto cycle for spark-ignition engines and the Diesel cycle.
2. The Otto cycle consists of isentropic compression, constant volume heat addition, isentropic expansion, and constant volume heat rejection. The Diesel cycle replaces the constant volume heat addition with constant pressure heat addition.
3. Equations are derived for the thermal efficiency of the Otto and Diesel cycles in terms of the compression ratio and temperature ratios between processes. The temperature ratios depend on whether the specific heats are constant or variable.
Similar to Use of Hydrogen in Fiat Lancia Petrol engine, Combustion Process and Determination of Optimum Valve Timing (20)
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
This document describes the design of an intelligent autonomous wheeled robot that uses RF transmission for communication. The robot has two modes - automatic mode where it can make its own decisions, and user control mode where a user can control it remotely. It is designed using a microcontroller and can perform tasks like object recognition using computer vision and color detection in MATLAB, as well as wall painting using pneumatic systems. The robot's movement is controlled by DC motors and it uses sensors like ultrasonic sensors and gas sensors to navigate autonomously. RF transmission allows communication between the robot and a remote control unit. The overall aim is to develop a low-cost robotic system for industrial applications like material handling.
This document reviews cryptography techniques to secure the Ad-hoc On-Demand Distance Vector (AODV) routing protocol in mobile ad-hoc networks. It discusses various types of attacks on AODV like impersonation, denial of service, eavesdropping, black hole attacks, wormhole attacks, and Sybil attacks. It then proposes using the RC6 cryptography algorithm to secure AODV by encrypting data packets and detecting and removing malicious nodes launching black hole attacks. Simulation results show that after applying RC6, the packet delivery ratio and throughput of AODV increase while delay decreases, improving the security and performance of the network under attack.
The document describes a proposed modification to the conventional Booth multiplier that aims to increase its speed by applying concepts from Vedic mathematics. Specifically, it utilizes the Urdhva Tiryakbhyam formula to generate all partial products concurrently rather than sequentially. The proposed 8x8 bit multiplier was coded in VHDL, simulated, and found to have a path delay 44.35% lower than a conventional Booth multiplier, demonstrating its potential for higher speed.
This document discusses image deblurring techniques. It begins by introducing image restoration and focusing on image deblurring. It then discusses challenges with image deblurring being an ill-posed problem. It reviews existing approaches to screen image deconvolution including estimating point spread functions and iteratively estimating blur kernels and sharp images. The document also discusses handling spatially variant blur and summarizes the relationship between the proposed method and previous work for different blur types. It proposes using color filters in the aperture to exploit parallax cues for segmentation and blur estimation. Finally, it proposes moving the image sensor circularly during exposure to prevent high frequency attenuation from motion blur.
This document describes modeling an adaptive controller for an aircraft roll control system using PID, fuzzy-PID, and genetic algorithm. It begins by introducing the aircraft roll control system and motivation for developing an adaptive controller to minimize errors from noisy analog sensor signals. It then provides the mathematical model of aircraft roll dynamics and describes modeling the real-time flight control system in MATLAB/Simulink. The document evaluates PID, fuzzy-PID, and PID-GA (genetic algorithm) controllers for aircraft roll control and finds that the PID-GA controller delivers the best performance.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
Use of Hydrogen in Fiat Lancia Petrol engine, Combustion Process and Determination of Optimum Valve Timing
1. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)
e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 9, Issue 4 (Nov. - Dec. 2013), PP 43-49
www.iosrjournals.org
www.iosrjournals.org 43 | Page
Use of Hydrogen in Fiat Lancia Petrol engine, Combustion
Process and Determination of Optimum Valve Timing
Harsh Tamakuwala1)
Dr. S. A. Channiwala2)
1
(Mechanical Engineering, National Institute of Technology, Surat, India)
1
(Mechanical Engineering,Professor, National Institute of Technology, Surat, India)
Abstract: To our path towards green economy, Hydrogen is often regarded to have a potential growth in the
coming future. However, the high cost of operation of fuel cell has often been a setback. If we could make use of
hydrogen gas as a fuel directly, the scope of development broadens. Owing to these aspects, this work primarily
focuses on the simulation technique of an Internal Combustion Spark Ignition Engine powered by Hydrogen gas.
The simulations of various stages have been carried out using the discrete approach, thereby investigating the
pressures and temperatures at various instants in the cycle. For the relative performance discussion we have
simulated the different cycles as ideal cycle, air fuel cycle and actual cycle. The resultant cyclic graph indicates
various discrepancies between ideal, air fuel and actual cycle. This analysis serves as a tool for a better
understanding of the variables involved and helps in optimizing engine design and fixing of various parameters,
including the determination of valve timings. Besides this, backfire, is the commonly faced problem with the
hydrogen engines. To reduce this effect, a fuel injectoris used for adding the gaseous fuel to the combustion
chamber.
Keyword: Actual cycle, air fuel cycle, backfire, discrete approach, fuel injector, fuel cell, hydrogen, ideal cycle,
spark plug, valve timings ,Fiat Lancia,inlet valve, exhaust valve, optimum valve timing .
I. Introduction
An intense research effort is on-going in the field of engines to develop new engines with improved
efficiency and decreased harmful emission. Further, to overcome the high dependency of automobiles on the
limited crude oil, huge focus is laid on the development of engines that are powered by alternate fuels, which
can even reduce the rate of pollution in the world that is currently being done by the hydrocarbons. Amongst all,
hydrogen, a fuel that powers the sun, is looking forward to run our vehicles too. The merits of using it as a fuel
are immense, few of which includes it production from renewable energy sources, a better efficiency over petrol
and harmless exhaust gases, mostly water vapour.
To study different engines, computer based thermodynamic models have been developed which can
predict the performance, avoiding the difficulties associated with the detailed experimental analysis.Simulation
of ideal cycle involves much less complexities since the initial conditions are known. But it is quite clear that an
ideal cycle cannot predict the exact conditions that an engine will face during its working period. An actual
model incorporates equations,which need to be solved using the method of iterations. Two approaches can be
followed for simulation of an IC engine- (i) The Differential Approach (ii) The Discrete Method. The first
method involves solving of partial differential equations based on energy, mass and momentum conservation
(1). The later model considers the calculations at each degree of crank rotation (or smaller) considering a few
assumptions at the initial stage but by iterating, ultimately reaching the exactconditions inside the combustion
chamber. This later approach is followed in this work and calculations are made which are discussed later in the
section of tables. The graphical charts plotted later, provides a comparison of the actual cycle with the ideal and
air fuel cycle.
Throughout this present work, a single cylinder, four stroke spark ignition engine, with a hydrogen fuel
injector, is used to illustrate all of the thermodynamic points to be made. The engine has a bore (B) of 73 mm
diameter, stroke length(L) of 70 mm, flywheel of radius (r) 35 mm and connecting rod of length (l) 170 mm.
Further the values presented here are for engine running at 1000 rpm. The compression ratio taken is 7.96 with a
clearance volume of 4.2023 x 10-5
m3
. The variations of specific heats, enthalpy and equilibrium constants of
different gases with temperature were obtained based on relationships established from JANAF tables.
II. Mathematical Models
The simulations of any engine is done and compared with the results of ideal cycle to get a clear idea of the
cycle.
2. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 44 | Page
2.1The Ideal Cycle&Air-fuel cycle
The ideal cycle serves as a standard for comparison of operations of various cycles. In ideal cycle we
have taken air as a working medium and a few standard assumptions for obtaining maximum achievable
efficiency.
Furthermore, by considering air-fuel cycle, we move a step closer towards actual analysis, since most
variations as a function of temperature are taken into consideration into this calculation, expect for the friction
and convective heat losses. Also the process of suction and exhaust is not taken into account in these two cycles.
The unknown value of temperature (T) at different crank angles is calculated using below equation obtained by
integrating the equation for entropy balance utilized only for air fuel analysis.
1
0
0 0
ln ln .... 1
V T
R a b T t
V t
vwhere C a bT
2.2The Discrete Approachfor Actual Cycle
In the present simulations, the governing parameters of the engine- pressure, temperature, volume and
mass are calculated at each degree of crank rotation. In an actual cycle, the remains of exhaust gases have to be
considered for simulation of suction process. However, the quantity of remaining exhaust gases and its
temperature and pressure can be known only after the whole cycle is simulated. Hence here initially these
parameters are assumed to simulate the processes of suction, compression, combustion, expansion and exhaust.
The parameters obtained after exhaust are taken to iterate the cycle again. The detailed method of simulation of
these processes is discussed in the following topics.
Assumptions:
In this work, the gas mixture has been considered as an ideal gas. Also, the losses in inlet and exhaust
manifold are not considered. In combustion chamber the gases have been considered to have uniform
temperature.Pre-ignition has not been considered and the combustion is considered to be occurring at constant
volume.The wall temperature (Twall),convective heat transfer coefficient (H) and friction loss (Fq) is calculated
using the following equations.
0.388 423 ... 2wallT K
1 07 2
2
2 8.5 10 ... 3
2
q mean
T TBL
F V
v
0.2 0.8 0.55 0.8
1 10.013 ... 4
meanH B P T V
2.2.1 Suction
The calculation of the process of suction begins with the assumption that the temperature remains
constant during the specific degree of crank rotation. Based on this and assuming the values of mass,
temperature and pressure of the exhaust gases we calculate the different parameters using the below mentioned
equations.
0 0
1
1
... 5
PV
P
V
1 .... 6atmP P P
1
2
... 7d
P
velocity u C
Where ρ is densitycalculated taking into consideration mass leaving or fresh air entering depending on the
pressure difference.
1 ... 8 m Au t
1 0 .... 9mass m m m
The calculations for mass fraction and gas constant are also done at the particular instant. Further, using the
values of calculated mass, mass fraction and taking specific heats of each constituent as a function of
temperature, obtained from JANAF Tables, We have than calculated the value of temperature by solving
quadratic equation obtained by the energy conservation in flow process using the equation below, since its value
changes due to exchange of mass.
3. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 45 | Page
1
0
1
0
0
0
1
0
; 0
2 ... 10
; 0
o
air
p p new
o p
p new
o p p air
C T C T
m C T m m
mC T
m C T mC T m
Using the momentum and energy conservation law, the modified temperature can be calculated considering the
losses occurring in friction and convection (q)which further can be used to find out modified pressure.
These new values are used to iterate the suction process from the start. Generally, 2-3 iterations give a good
level of accurate values.
2.2.2Compression
2.2.2.1 Compression prior to injection
After the suction stroke, the calculations of compression begin by assuming adiabatic process and hence
calculating the temperature T1 after each 10
rotation throughout the stroke.
1 1
.... 11d dT V T V
The losses in compression follow same approach as in suction, thereby giving variation in temperature.
Further,the new value of γ is calculated at an average temperature of corrected and initialones. Then using this
value of γ we do good number of iterations to get the exact temperature. Pressure at this corrected temperature
can be obtained easily by,
.... 12d d
d
P V P V
T T
2.2.2.2 Fuel injection
Fuel injector is opened at a specific degree of crank rotation during compression and the process
follows the one followed during suction. It has been started at 2800
and kept open till the required particular mass
entersconsidering pre-ignition and turbulence factors. Inlet temperature of fuel is 300K.
2.2.2.3 Compression post injection
After the injection of fuel the same process of compression is followed again, once the fuel injector is
shut off.
2.2.3 Combustion
The simulation of combustion involves complexities of solving seven equations to obtain moles of six
products and the temperature after combustion. To solve these equations, the method of iteration has been used.
These equations can be obtained as:
The combustion equation yields three equations by mole comparison of H, O and N, where the reactant
parameters-the temperature, pressure, moles and mass can be knownfromcompression stroke.
2 2 2 2 2 2
2
xH + yO + y'N aO +bN +cH +
dH O+eOH+fNO
2 2 2 .... 13 2 ' 2b f ... 14
2 2 .... 15
x c d e y
y a d e f
The equilibrium constants can be expressed in terms of partial pressure as:
2
2 2 2 2
2 2
2 2
1 22
2
1
... 16 ... 17
... 18
H O OH
H o H o
NO
N o
P P
k k
P P P P
P
k
P P
Finally the energy balance on the reactant and product sides gives
.... 19p j j r i i
p r
H n RT H n RT
Thus, to solve these 7 equations, initially we can suppose a temperature and find out the values of the constants
in equation (13) - (18). The values of x and y are determined from the mass and moles fractions. Then the
obtained values are verified using equation (19). After multiple iterations, we have obtained the moles of the
products and the temperature which can be used to find pressure by ideal gas equation.
4. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 46 | Page
0
0.0002
0.0004
0.0006
0 100 200 300
ExhaustValveArea
(m2)
θ
2.2.4 Expansion and Exhaust
The simulation of expansion, after combustion, follows the same approach as done in the compression
stroke 3.2.2. Similarly, using the equations and method of suction 3.2.1, we can simulate the exhaust to obtain
the final pressure and temperature.
This final temperature and pressure is used as initial data for suction to iterate the whole cycle repeatedly, until
sufficient accuracy in values of these parameters are not obtained.
2.2.5 Area Planar of the inlet-exhaust openings
Since the analysis is based onFiat Lanciaengine, in this work, for our simulation, we have taken the
area of the openings of the valve, keeping the ascent and descent angle of both the valves as designed. Also the
variations in the valve lift and area of opening of the valves has been taken as designed which is presented in the
graph below. However due to large area of the opening the exhaust blow-down loss is high. Hence various
simulations are run for different areas and finally reduced the area by 75% of the practical valves for appropriate
suction and compression.
2.2.6 Determination of valve timings
We analyzed different valve timings to fix an optimum value giving maximum efficiency. But the inlet
and exhaust valve advance are mutually dependent. However, the changing in work done by the engine varies
quite less with inlet advance, since the pressure during the inlet valve opening is quite less as compared to the
exhaust valve opening, as observed from the table (3). We have, hence, initially fixed the inlet valve advance as
100
before TDC, as referred from V. Ganesan [3], to thereby determine the accurate valve timings for the
exhaust valve. Now, using the previously fixed timings, we can finally obtain the same for the inlet valve
considering maximum mass entry of Oxygen. The parameters for different valve timings have been noted in the
table (6).
According to the data of the engine valves, the inlet valve is kept open for 2100
and exhaust valve for 2400
of
crank angle.
III. Simulation results
Table (a). Variations in Exhaust valve timings
Exhaust Advance
(Before BDC)
Work Done (J) Efficiency
(%)
40 483.95 39.506
35 484.379 39.541
30 499.18 40.75
25 483.915 39.503
20 482.905 39.42
Table (b). Variations in inlet valve timings
InletAdvance (Before
TDC)
Amount of Oxygen entering
(kg) (x 10e-4)
22 0.7978
16 0.8146
15 0.81476
14 0.8136
10 0.78677
0
0.0002
0.0004
0.0006
0 100 200 300
InletValveArea
(m2)
θ
Figure 1: Inlet Valve Area vs θ Figure 2: Inlet Valve Area vs θ
5. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 47 | Page
Table 1.Suction
Theta
Volume
(m3)
(10e-5)
Temperature
(K)
Pressure
N/m2
(10e5)
1 42.050 510.1035 0.9934
2 42.130 511.1578 1.0264
180 33.4851 325.2976 0.9871
194 33.1433 325.2099 1.0020
195 33.0925 325.2101 1.0034
Table 2.Compression
Theta
Volume (m3
)
(10-5
)
Temperature
(K)
Pressure
(10e5)
196 33.038 325.2066 1.0034
280 17.815 411.3374 2.32356
Mass before Injection 3.5622 x 10-4
281 17.555 408.1219 2.4166
283 17.033 402.215 2.6071
285 16.512 396.9172 2.8089
287 15.992 392.1395 3.0233
289 15.475 387.8091 3.2511
291 14.960 383.8663 3.4937
Mass After Fuel is
Injected 3.6496 x 10-4
360 4.2024 622.6619 20.504
*** = Fuel Injector is kept open
Table 3. After Combustion Parameters
Compound Variables Moles
O2 a 2.3966 x 10-8
N2 b 0.0095
H2 c 4.921 x 10-10
H2O d 0.0050
OH e 3.9899 x 10-9
NO f 4.32 x 10-5
Pressure 89.54
Temperature 3131
Table 4.Expansion
Theta
Volume
(m3
) (10e-5)
Temperature
(K)
Pressure
N/m2
(10e5)
361 4.2041 3130.674 89.49586
509 31.7668 1865.216 7.066
510 31.8742 1863.46 7.035
Table 5. Exhaust
Theta
Volume
(m3) (10e-
4)
Temperature
(K)
Pressure
N/m2 (10e5)
511 31.9780 1863.46 7.035
715 4.2795 713.1197 0.979
716 4.2534 663.1463 0.9828
719 4.2073 550.5722 0.9911
720 4.2026 521.9448 0.9934
6. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 48 | Page
IV. Graphs
7. Use of Hydrogen in Petrol engine, Combustion Process and Determination of Optimum Valve Timing
www.iosrjournals.org 49 | Page
V. Interpretation
The dependency of efficiency is quite low on inlet advance, compared to exhaust advance since the
pressure is quite high at exhaust opening in contrast to the instant at inlet advance angle.
By calculating efficiencies for various exhaust angle advance, maximum efficiency is found to be occurring at
5100
, resulting in optimized piston work against high cylinder pressure and loss of expansion stroke and is
closed at 100
after TDC.
At 1000 rpm and Ф=1, we selected -150
and 1950
of crank rotation for opening and closing of inlet valve to
permit the maximum entry of O2 gas in enginesince inlet valve is designed to be kept open for 2100
.
During the crank rotation angle of 2810
-2910
, there is rapid increase in pressure because of injected hydrogen in
combustion chamber. For equivalence ratio equal to 1 the mass entry required is 8.74 x 10-6
kg and hence the
fuel injector is kept open for 100
of crank rotation.
At equivalence ratio 1, combustion of 1g of H2 produces 0.13334 g of NO and hence the %NO emission is
0.391% which is very less considering NO to be a dangerous emission.
The work done in the actual cycle is 499.18 J/cycle and hence the efficiency of the cycle is 40.75% and the
efficiency of ideal cycle is 56.25 %
VI. Conclusions
From the results of simulation, we obtained the efficiency of actual cycle 40.75% which is 72.39% of
the ideal cycle when Exhaust valve advance is 300
and closes 100
after TDC. Inlet valve advance is 150
before
TDC and closes at 195c
of crank rotation.We have seen that the emission percentage of NO has been very less
and here there is no emission of CO2 orCO and hence it is environment friendly.
References
[1] Books: Heywood J., Internal Combustion Engine Fundamentals, 1st
Edition, Tata McGraw-Hill,USA, 1988, chap. 9-10.
[2] Book: V. Ganesan, Internal Combustion engines.
[3] Murat CINIVIZ, Hydrogen use in internal combustion engine:A Review Mechanical engineering department, Selcuk University,
Konya Turkey, 21011
[4] http://kinetics.nisd.gov/janaf
[5] Vikas Patel., Analysis of Hydrogen engine by differential and discrete approach, Ph.D Thesis, S. V. N.I.T, Surat, 2006
[6] Jose J Granda, Karl Sime, Computer Aided Modelling of Four Stroke Internal combustion engine, California State University,
Sacramento
[7] http://www.engr.colostate.edu
[8] J.M.Gones Antunes, R Mikalsen, A. P. Roskilly, An experimental study of a direct injection compression ignition hydrogen engine,
Sir Joseph Institute for Energy Research, Newcastle University, England U.K.
[9] Probir Kumar Bose, Rahul Banerjee, and Madhujit Deb, Hydrogen and Diesel Combustion on a Single Cylinder Four Stroke Diesel
Engine in Dual FuelMode with Varying Injection Strategies
[10] VVN BHASKAR, Dr. R. HARI PRAKASH, Dr. B. DURGA PRASAD, HYDROGEN FUELLED IC ENGINE – ANOVERVIEW
[11] “Simulation of Compression Ignition Engine Processes with Jatropha Bio-Diesel”, Presented & Published in the proceedings
ofInternational Conf.on Bio-Fuels, Vision-2015, Oct. 13-15, 2006, Engg. College Bikaner, India.
[12] B.Rajendra Prasath, E.Leelakrishnan, N. Lokesh, H. Suriyan, E. Guru Prakash, K. Omur Mustaq Ahmed Hydrogen Operated Internal
Combustion Engines –ANew Generation Fuel Department of Automobile Engineering, Sriram Engineering College, Anna University
Chennai, India.