This document summarizes an article that investigates the impact of fuel composition on auto-ignition in HCCI engines. The article tests various reference fuels and gasoline blends in a single-cylinder HCCI engine to compare auto-ignition timing. It finds that existing metrics like Octane Index and HCCI Index do not fully capture the effect of fuel composition. Different fuel additives like ethanol impact auto-ignition differently depending on the base gasoline. Low-temperature heat release correlates better with auto-ignition timing than other heat release metrics for some gasoline fuels.
An Experimental Investigation on Performance and Emission Parameters using WT...Working as a Lecturer
this ppt for the Dissertation work for the An Experimental Investigation on Performance and Emission Parameters using WTO – Diesel blend with Additives in a Diesel Engine,contain all detail anlysis with result.
Reduxco is a fuel catalyst that improves combustion efficiency and reduces emissions. It is added to hydrocarbon fuels in small amounts. When used in diesel and heavy oil engines, it can:
Reduce fuel consumption by 4-12% depending on the engine load.
Significantly reduce emissions of particulate matter (PM), hydrocarbons (HC), carbon monoxide (CO), and soot.
Improve the combustion process by reducing the surface tension of coal and promoting the complete combustion of fuels.
This document discusses using alcohol as an alternative fuel for internal combustion engines. It outlines that crude oil and petroleum products will become scarce, so alternative fuels are needed. E85 fuel is discussed, which is a blend of 85% ethanol and 15% gasoline that can be used in flexible fuel vehicles. The document covers the ethanol production process and describes the benefits of higher octane rating, cooling effects, and lower emissions of alcohol fuels compared to gasoline. Both advantages like reduced emissions and disadvantages like lower energy content are summarized. The conclusion is that finding alternatives to fossil fuels like alcohol will be important as crude oil is depleted.
The document discusses the process of ethanol production from corn. It explains that corn is first ground into flour and mixed with water and enzymes to break it down into sugars. Yeast ferments the sugars to produce ethanol, which is then distilled. The byproducts of distillation like dried grains and carbon dioxide are also discussed. The document also covers using ethanol in cars, including types of ethanol blends and modifications needed to vehicles to enable their use.
This is my final year seminar presentation on HCCI Engine presented by me at SKIT, Jaipur.
This presentation contains a basic introduction of HCCI Engine.
Some of the contents are copied from various websites so some details are subjected to copyright law.
I am using these information only for the educational purpose
Modifications are needed in gasoline engines to use ethanol fuel blends. For blends up to E10, no changes are typically needed. For higher blends, modifications like increasing the diameter of inlet orifices and the accelerator pump are required to properly adjust the air-fuel ratio. Additional changes like increasing the compression ratio or installing pre-heating systems may be needed for cold starting when using high-ethanol blends. Proper adjustments can help utilize the higher octane and cleaner burning properties of ethanol fuel in engines.
Stealth technology uses techniques to make aircraft, ships, and other objects invisible to radar. It has been developed since World War II to provide military advantages. Key aspects of stealth technology include shaping vehicles to reduce radar reflections, using radar absorbing materials, and burying engines and weapons internally to minimize radar signatures. The F-117 Nighthawk stealth fighter demonstrated the effectiveness of these techniques through its distinctive delta wing design and use of radar absorbing coating. Future stealth aircraft could use plasma stealth to envelop vehicles in ionized gas and make them invisible to radar.
An Experimental Investigation on Performance and Emission Parameters using WT...Working as a Lecturer
this ppt for the Dissertation work for the An Experimental Investigation on Performance and Emission Parameters using WTO – Diesel blend with Additives in a Diesel Engine,contain all detail anlysis with result.
Reduxco is a fuel catalyst that improves combustion efficiency and reduces emissions. It is added to hydrocarbon fuels in small amounts. When used in diesel and heavy oil engines, it can:
Reduce fuel consumption by 4-12% depending on the engine load.
Significantly reduce emissions of particulate matter (PM), hydrocarbons (HC), carbon monoxide (CO), and soot.
Improve the combustion process by reducing the surface tension of coal and promoting the complete combustion of fuels.
This document discusses using alcohol as an alternative fuel for internal combustion engines. It outlines that crude oil and petroleum products will become scarce, so alternative fuels are needed. E85 fuel is discussed, which is a blend of 85% ethanol and 15% gasoline that can be used in flexible fuel vehicles. The document covers the ethanol production process and describes the benefits of higher octane rating, cooling effects, and lower emissions of alcohol fuels compared to gasoline. Both advantages like reduced emissions and disadvantages like lower energy content are summarized. The conclusion is that finding alternatives to fossil fuels like alcohol will be important as crude oil is depleted.
The document discusses the process of ethanol production from corn. It explains that corn is first ground into flour and mixed with water and enzymes to break it down into sugars. Yeast ferments the sugars to produce ethanol, which is then distilled. The byproducts of distillation like dried grains and carbon dioxide are also discussed. The document also covers using ethanol in cars, including types of ethanol blends and modifications needed to vehicles to enable their use.
This is my final year seminar presentation on HCCI Engine presented by me at SKIT, Jaipur.
This presentation contains a basic introduction of HCCI Engine.
Some of the contents are copied from various websites so some details are subjected to copyright law.
I am using these information only for the educational purpose
Modifications are needed in gasoline engines to use ethanol fuel blends. For blends up to E10, no changes are typically needed. For higher blends, modifications like increasing the diameter of inlet orifices and the accelerator pump are required to properly adjust the air-fuel ratio. Additional changes like increasing the compression ratio or installing pre-heating systems may be needed for cold starting when using high-ethanol blends. Proper adjustments can help utilize the higher octane and cleaner burning properties of ethanol fuel in engines.
Stealth technology uses techniques to make aircraft, ships, and other objects invisible to radar. It has been developed since World War II to provide military advantages. Key aspects of stealth technology include shaping vehicles to reduce radar reflections, using radar absorbing materials, and burying engines and weapons internally to minimize radar signatures. The F-117 Nighthawk stealth fighter demonstrated the effectiveness of these techniques through its distinctive delta wing design and use of radar absorbing coating. Future stealth aircraft could use plasma stealth to envelop vehicles in ionized gas and make them invisible to radar.
Stringent emission standards and the need to reduce greenhouse gas, CO2 emissions from vehicles has led to intensive research on new combustion systems namely, the Homogeneous charge compression ignition (HCCI) or controlled auto ignition (CAI) engines. At auto ignition temperature the fuel is auto ignited and a same amount of power will be produced as the traditional engines. Heating of catalytic converter reduces the emissions.
This document presents a mathematical model of HCCI (Homogeneous Charge Compression Ignition) engine operation fueled with ethanol.
The model is based on conservation of mass and energy, and uses a two-step chemical reaction mechanism to model combustion. Wall heat transfer is also included. Simulation results from the model show good correlation with experimental cylinder pressure data from a modified diesel engine operated in HCCI mode.
The model could potentially be used to develop control strategies to stabilize HCCI combustion for practical application in engines.
1. The document discusses research on developing a high-efficiency, low-emissions electrical generator that can operate on hydrogen fuels using internal combustion engine technology.
2. Experimental results showed that hydrogen combustion in a rapid compression machine approached constant volume combustion, indicating high efficiency. Combustion occurred very rapidly.
3. The generator design uses a free piston linear alternator configuration to enable high compression ratios and rapid combustion through homogeneous charge compression ignition combustion of hydrogen, with the goal of approaching ideal Otto cycle performance and efficiency.
The document discusses research on developing a high-efficiency electrical generator using an internal combustion engine that can operate on hydrogen and hydrogen-containing fuels. The objective is to provide renewable energy utilization with high efficiency and low emissions. A full-scale prototype generator is being developed in collaboration with industrial partners. It will use a free piston linear alternator design capable of high compression ratios and fast, constant volume combustion for improved efficiency compared to traditional engines.
HCCI Engine Performance Evaluation Using FORTEReaction Design
This note describes how the FORTÉ Simulation Package can be used to include detailed chemistry in internal combustion engine simulations. The enhanced chemistry solution techniques in FORTÉ allow detailed chemistry to be efficiently included in the FORTÉ computational fluid dynamics (CFD) calculation. These enhancements allow designers to accurately predict ignition, emissions, combustion duration, and engine performance without sacrificing geometric fidelity and without compromising accuracy for solution efficiency.
1. The document discusses redesigning the inlet valve of an HCCI engine to improve performance and lifetime.
2. It proposes using a titanium alloy for the valve material instead of nickel chromium, and adding a hollow path inside filled with sodium liquid metal to help conduct heat away from the valve.
3. Analysis of the redesigned valve using CAD software shows improvements in withstanding pressure and reducing temperature fluctuations compared to the original design, indicating better efficiency and lifespan.
A study and analysis on hcci engine's inlet valveiaemedu
1. The document discusses a study and analysis of the inlet valve for an HCCI (Homogeneous Charge Compression Ignition) engine.
2. It aims to redesign the typical inlet valve through innovative design and new material composition to improve the overall performance, working life, and thermal conductivity of the component.
3. The redesigned inlet valve is analyzed using advanced CAD packages and the results show improvements in efficiency and reducing wear and tear on the valve contacting surfaces.
1. The document discusses a study and analysis of the inlet valve for an HCCI (Homogeneous Charge Compression Ignition) engine.
2. It aims to redesign the typical inlet valve through innovative design and new material composition to improve the overall performance, working life, and thermal conductivity of the component.
3. The redesigned inlet valve is analyzed using advanced CAD packages and the results show improvements in efficiency and reducing wear and tear on the valve contacting surfaces.
Evaluation of green propellants for an icbm post boost propulsion systemMarcus 2012
This document evaluates green propellants for use in a notional next-generation post-boost propulsion system (PBPS) for intercontinental ballistic missiles (ICBMs). It identifies candidate green propellants using an overall evaluation criterion (OEC) method accounting for toxicity, performance, and technical feasibility. Promising candidates were used to develop sized PBPS concepts, which were evaluated based on weight, cost, and technical risk. Results indicate high-test peroxide (HTP) combined with either an ethanol-based nontoxic hypergolic miscible fuel or a competitive impulse non-carcinogenic hypergol is very viable for the PBPS application due to performance and reduced toxicity over the current hydrazine-based
This document discusses the development and application of organic Rankine cycle (ORC) technology for recovering waste heat from vehicle internal combustion engines (ICEs). It provides an overview of ORC technology and its potential to improve ICE efficiency and reduce emissions. The document also reviews representative ORC prototypes developed by vehicle manufacturers like BMW, Honda, and Cummins, which demonstrated efficiency improvements but noted barriers to commercialization like cost and complexity.
The use of blend methanol at High Compression Ratio in spark-ignition engineijsrd.com
it can be obviously seen the world's fossil fuel reserves are limited. It is well known those passenger vehicles are dependent on fossil fuels such as gasoline, diesel fuel, liquefied petroleum gas, and natural gas. The fossil fuel used in passenger vehicles induces the air pollution, acid rains, build-up of carbon dioxide and crude oil; petroleum product will become very scarce and costly. Hence, there is a progressively interest related with using non-fossil sources in vehicles. Especially, the alcohol fuels (methanol, ethanol etc.) have been showed good candidates as alternative fuels for the vehicles equipped with SI. In this experimental study, the effect of methanol (30% and 40%) with gasoline (70% and 60%) tested to measure the performance and emission of 4- cylinder spark ignition multi-port fuel injection (MPFI) engine. The tests with/without methanol blends and increase compression ratio 8.8:1 to 11:1 were performed on a rope belt dynamometer while running the engine at speed 1500 rpm at different varying engine load. In these tests measure engine performance parameters like engine torque, brake specific fuel consumption, brake thermal efficiency and exhaust emission. After experimental investigations to measure engine power increase 10.6%, brake specific fuel consumption decrease 4.2%, brake thermal efficiency increase and exhaust gas emission is decrease with use of methanol blend fuel with gasoline.
This document provides a review of the Homogenous Charged Compression Ignition (HCCI) engine. It discusses the history and development of HCCI engines, which were first discovered as an alternative to two-stroke engines. HCCI engines have the potential for lower emissions and improved fuel efficiency compared to traditional spark ignition and compression ignition engines. However, controlling the autoignition of the premixed fuel-air charge across different operating conditions is challenging. The document outlines several combustion challenges for HCCI engines, including controlling the combustion phase, limited operating range, preparing a homogeneous fuel-air charge, cold starting issues, and high hydrocarbon and carbon monoxide emissions. It then discusses various control strategies that have been explored
This document summarizes an experimental study of a modified diesel engine operating in homogeneous charge compression ignition (HCCI) combustion mode compared to the original diesel combustion mode. The study found that HCCI combustion provided very low NOx and soot emissions but had challenges with hydrocarbon emissions, fuel consumption, ignition timing control, and performance at high loads. Cooled exhaust gas recirculation was used to control in-cylinder NOx production. Test results showed significant reductions in NOx and smoke emissions for HCCI combustion compared to diesel mode, along with generally higher hydrocarbon and carbon monoxide emissions due to early fuel injection timing and fuel adhering to cylinder walls.
Ricardo low carbon vehicle partnership life cycle co2 measure - final reportUCSD-Strategic-Energy
A Ricardo study released in June highlighted the increasing importance of accounting for whole life carbon emissions to compare the GHG of low carbon vehicles. Ricardo found that a typical medium sized family car will create around 24 tonnes of CO2 during its life cycle, while a battery electric vehicle (BEV) will produce around 18 tonnes over its life. For a battery EV, 46% of its total carbon footprint is generated at the factory, before it has travelled a single mile. If the charging source is renewable energy, i.e., “Tailpipe Endgame” rather than 500g/kWH that Ricardo assumed, then the battery EV would have a life cycle C02 footprint only 37% that of a standard gasoline vehicle. The report was prepared by Ricardo for, and in collaboration with, the expert membership of the Low Carbon Vehicle Partnership that includes major vehicle manufacturers and oil companies, and it will be a strong baseline along with other analyses for all present and future funded efforts to document the environmental benefits of renewable energy charging of BEVs.
This document presents an experimental investigation into the effects of adding HHO gas (produced via electrolysis of water) and varying the compression ratio on the performance characteristics of a constant speed diesel engine. The HHO gas was added at a constant flow rate while testing compression ratios of 16, 17, and 18 at varying loads. Test results showed that adding HHO gas decreased fuel consumption and increased indicated thermal efficiency compared to diesel alone. Fuel savings of up to 6.5% were observed. Brake thermal efficiency was not significantly affected by HHO gas addition. Mechanical efficiency increased with higher compression ratio and load. Overall, a compression ratio of 18 showed the most improvement in engine performance when HHO gas was added.
SUPERCRITICAL FUEL INJECTION-A PROMISING TECHNOLOGY FOR IMPROVED FUEL EFFICIE...saeedahmad7007
The document discusses transonic combustion, which is a new combustion process that involves injecting fuel into an engine cylinder as a supercritical fluid using a patented fuel injection system. Supercritical fuel mixes rapidly and ignites in multiple locations, resulting in high combustion efficiency. The system allows unthrottled engine operation and stratified charge at part load for improved efficiency. Test results show significant reductions in fuel consumption and emissions. The key aspects of the system involve heating the fuel to a supercritical state before injection to improve mixing and achieving precise ignition timing to utilize most of the heat release.
In tech advanced-power_generation_technologies_fuel_cellsYogendra Pal
This document provides an overview of fuel cell technologies. It discusses how fuel cells work by directly converting chemical energy to electrical energy through electrochemical reactions, avoiding combustion. This allows for higher efficiencies than combustion-based power generation. It also summarizes the key components of a fuel cell and different fuel cell configurations. The document focuses on solid oxide fuel cells (SOFCs) and their potential for stationary power generation applications due to their high operating temperatures.
Transonic novel fuel injection system engine.pdfCSA Welfare
The document discusses Transonic Combustion's novel fuel injection technology called TSCi. TSCi injects fuel into the engine cylinder in a supercritical state, which allows for more precise control over ignition timing and location of combustion. This enables significantly higher efficiency combustion compared to traditional engines. Specifically:
1) TSCi raises the fuel to a supercritical state before injection, allowing for rapid mixing with air and spontaneous ignition in multiple locations for high heat release and efficiency.
2) Testing has shown promise, with one modified gasoline engine achieving 98 mpg at 50 mph.
3) By controlling ignition timing to occur after top dead center, all work from combustion produces positive work on the piston,
The document is a seminar report on HCCI and CAI engines presented by Saurabh Y. Joshi. It discusses the basics of HCCI and CAI, including the working principles of HCCI engines. CAI can be used in gasoline engines with high compression ratios. Methods to achieve CAI include using EGR, increasing compression ratio, and adjusting intake conditions. CAI engines have very low NOx emissions but higher HC and CO emissions than SI engines. While HCCI/CAI engines provide improved efficiency, challenges remain around combustion control and cold starting. Ongoing research continues to address these challenges.
In this investigation, Cashew nut shell liquid (CNSL) biodiesel, hydrogen and
ethanol (BHE) mixtures remained verified in a single cylinder direct-injection diesel
engine to examine the recital plus discharge features of the engine. The engine stayed
verified at supreme force and rapidity of 1500 rpm. The ethanol remained
supplemented 5%, 10% and 15% correspondingly through enhanced CNSL as well as
hydrogen functioned twin fuel engine. The consequences designate that while
associated through well-ordered diesel and biodiesel-hydrogen process, the recital
and discharge features of ethanol mixtures obligates upgraded. The brake thermal
efficiency upsurges somewhat through 10% ethanol mixtures and nope noteworthy
enhancement by advanced ethanol mixtures. The exhaust gas temperature and NOx
release augmented by 10% ethanol accumulation. Through greater proportion of
ethanol in the biodiesel hydrogen (BH) mixtures the HC, CO releases might upsurge.
However the routine of 10% ethanol might diminish the HC and CO releases
equally. Overall the BHE mixtures ensure greater NOx discharges, associated by
biodiesel and diesel energy. Throughout the BHE mixtures offers lesser HC, CO, as
well as greater NOx release associated through the well-ordered diesel fuel.
Nevertheless the embellishments of added ethanol thru BH mixtures require no
substantial enhancement in the recital discharge and stages
More Related Content
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Stringent emission standards and the need to reduce greenhouse gas, CO2 emissions from vehicles has led to intensive research on new combustion systems namely, the Homogeneous charge compression ignition (HCCI) or controlled auto ignition (CAI) engines. At auto ignition temperature the fuel is auto ignited and a same amount of power will be produced as the traditional engines. Heating of catalytic converter reduces the emissions.
This document presents a mathematical model of HCCI (Homogeneous Charge Compression Ignition) engine operation fueled with ethanol.
The model is based on conservation of mass and energy, and uses a two-step chemical reaction mechanism to model combustion. Wall heat transfer is also included. Simulation results from the model show good correlation with experimental cylinder pressure data from a modified diesel engine operated in HCCI mode.
The model could potentially be used to develop control strategies to stabilize HCCI combustion for practical application in engines.
1. The document discusses research on developing a high-efficiency, low-emissions electrical generator that can operate on hydrogen fuels using internal combustion engine technology.
2. Experimental results showed that hydrogen combustion in a rapid compression machine approached constant volume combustion, indicating high efficiency. Combustion occurred very rapidly.
3. The generator design uses a free piston linear alternator configuration to enable high compression ratios and rapid combustion through homogeneous charge compression ignition combustion of hydrogen, with the goal of approaching ideal Otto cycle performance and efficiency.
The document discusses research on developing a high-efficiency electrical generator using an internal combustion engine that can operate on hydrogen and hydrogen-containing fuels. The objective is to provide renewable energy utilization with high efficiency and low emissions. A full-scale prototype generator is being developed in collaboration with industrial partners. It will use a free piston linear alternator design capable of high compression ratios and fast, constant volume combustion for improved efficiency compared to traditional engines.
HCCI Engine Performance Evaluation Using FORTEReaction Design
This note describes how the FORTÉ Simulation Package can be used to include detailed chemistry in internal combustion engine simulations. The enhanced chemistry solution techniques in FORTÉ allow detailed chemistry to be efficiently included in the FORTÉ computational fluid dynamics (CFD) calculation. These enhancements allow designers to accurately predict ignition, emissions, combustion duration, and engine performance without sacrificing geometric fidelity and without compromising accuracy for solution efficiency.
1. The document discusses redesigning the inlet valve of an HCCI engine to improve performance and lifetime.
2. It proposes using a titanium alloy for the valve material instead of nickel chromium, and adding a hollow path inside filled with sodium liquid metal to help conduct heat away from the valve.
3. Analysis of the redesigned valve using CAD software shows improvements in withstanding pressure and reducing temperature fluctuations compared to the original design, indicating better efficiency and lifespan.
A study and analysis on hcci engine's inlet valveiaemedu
1. The document discusses a study and analysis of the inlet valve for an HCCI (Homogeneous Charge Compression Ignition) engine.
2. It aims to redesign the typical inlet valve through innovative design and new material composition to improve the overall performance, working life, and thermal conductivity of the component.
3. The redesigned inlet valve is analyzed using advanced CAD packages and the results show improvements in efficiency and reducing wear and tear on the valve contacting surfaces.
1. The document discusses a study and analysis of the inlet valve for an HCCI (Homogeneous Charge Compression Ignition) engine.
2. It aims to redesign the typical inlet valve through innovative design and new material composition to improve the overall performance, working life, and thermal conductivity of the component.
3. The redesigned inlet valve is analyzed using advanced CAD packages and the results show improvements in efficiency and reducing wear and tear on the valve contacting surfaces.
Evaluation of green propellants for an icbm post boost propulsion systemMarcus 2012
This document evaluates green propellants for use in a notional next-generation post-boost propulsion system (PBPS) for intercontinental ballistic missiles (ICBMs). It identifies candidate green propellants using an overall evaluation criterion (OEC) method accounting for toxicity, performance, and technical feasibility. Promising candidates were used to develop sized PBPS concepts, which were evaluated based on weight, cost, and technical risk. Results indicate high-test peroxide (HTP) combined with either an ethanol-based nontoxic hypergolic miscible fuel or a competitive impulse non-carcinogenic hypergol is very viable for the PBPS application due to performance and reduced toxicity over the current hydrazine-based
This document discusses the development and application of organic Rankine cycle (ORC) technology for recovering waste heat from vehicle internal combustion engines (ICEs). It provides an overview of ORC technology and its potential to improve ICE efficiency and reduce emissions. The document also reviews representative ORC prototypes developed by vehicle manufacturers like BMW, Honda, and Cummins, which demonstrated efficiency improvements but noted barriers to commercialization like cost and complexity.
The use of blend methanol at High Compression Ratio in spark-ignition engineijsrd.com
it can be obviously seen the world's fossil fuel reserves are limited. It is well known those passenger vehicles are dependent on fossil fuels such as gasoline, diesel fuel, liquefied petroleum gas, and natural gas. The fossil fuel used in passenger vehicles induces the air pollution, acid rains, build-up of carbon dioxide and crude oil; petroleum product will become very scarce and costly. Hence, there is a progressively interest related with using non-fossil sources in vehicles. Especially, the alcohol fuels (methanol, ethanol etc.) have been showed good candidates as alternative fuels for the vehicles equipped with SI. In this experimental study, the effect of methanol (30% and 40%) with gasoline (70% and 60%) tested to measure the performance and emission of 4- cylinder spark ignition multi-port fuel injection (MPFI) engine. The tests with/without methanol blends and increase compression ratio 8.8:1 to 11:1 were performed on a rope belt dynamometer while running the engine at speed 1500 rpm at different varying engine load. In these tests measure engine performance parameters like engine torque, brake specific fuel consumption, brake thermal efficiency and exhaust emission. After experimental investigations to measure engine power increase 10.6%, brake specific fuel consumption decrease 4.2%, brake thermal efficiency increase and exhaust gas emission is decrease with use of methanol blend fuel with gasoline.
This document provides a review of the Homogenous Charged Compression Ignition (HCCI) engine. It discusses the history and development of HCCI engines, which were first discovered as an alternative to two-stroke engines. HCCI engines have the potential for lower emissions and improved fuel efficiency compared to traditional spark ignition and compression ignition engines. However, controlling the autoignition of the premixed fuel-air charge across different operating conditions is challenging. The document outlines several combustion challenges for HCCI engines, including controlling the combustion phase, limited operating range, preparing a homogeneous fuel-air charge, cold starting issues, and high hydrocarbon and carbon monoxide emissions. It then discusses various control strategies that have been explored
This document summarizes an experimental study of a modified diesel engine operating in homogeneous charge compression ignition (HCCI) combustion mode compared to the original diesel combustion mode. The study found that HCCI combustion provided very low NOx and soot emissions but had challenges with hydrocarbon emissions, fuel consumption, ignition timing control, and performance at high loads. Cooled exhaust gas recirculation was used to control in-cylinder NOx production. Test results showed significant reductions in NOx and smoke emissions for HCCI combustion compared to diesel mode, along with generally higher hydrocarbon and carbon monoxide emissions due to early fuel injection timing and fuel adhering to cylinder walls.
Ricardo low carbon vehicle partnership life cycle co2 measure - final reportUCSD-Strategic-Energy
A Ricardo study released in June highlighted the increasing importance of accounting for whole life carbon emissions to compare the GHG of low carbon vehicles. Ricardo found that a typical medium sized family car will create around 24 tonnes of CO2 during its life cycle, while a battery electric vehicle (BEV) will produce around 18 tonnes over its life. For a battery EV, 46% of its total carbon footprint is generated at the factory, before it has travelled a single mile. If the charging source is renewable energy, i.e., “Tailpipe Endgame” rather than 500g/kWH that Ricardo assumed, then the battery EV would have a life cycle C02 footprint only 37% that of a standard gasoline vehicle. The report was prepared by Ricardo for, and in collaboration with, the expert membership of the Low Carbon Vehicle Partnership that includes major vehicle manufacturers and oil companies, and it will be a strong baseline along with other analyses for all present and future funded efforts to document the environmental benefits of renewable energy charging of BEVs.
This document presents an experimental investigation into the effects of adding HHO gas (produced via electrolysis of water) and varying the compression ratio on the performance characteristics of a constant speed diesel engine. The HHO gas was added at a constant flow rate while testing compression ratios of 16, 17, and 18 at varying loads. Test results showed that adding HHO gas decreased fuel consumption and increased indicated thermal efficiency compared to diesel alone. Fuel savings of up to 6.5% were observed. Brake thermal efficiency was not significantly affected by HHO gas addition. Mechanical efficiency increased with higher compression ratio and load. Overall, a compression ratio of 18 showed the most improvement in engine performance when HHO gas was added.
SUPERCRITICAL FUEL INJECTION-A PROMISING TECHNOLOGY FOR IMPROVED FUEL EFFICIE...saeedahmad7007
The document discusses transonic combustion, which is a new combustion process that involves injecting fuel into an engine cylinder as a supercritical fluid using a patented fuel injection system. Supercritical fuel mixes rapidly and ignites in multiple locations, resulting in high combustion efficiency. The system allows unthrottled engine operation and stratified charge at part load for improved efficiency. Test results show significant reductions in fuel consumption and emissions. The key aspects of the system involve heating the fuel to a supercritical state before injection to improve mixing and achieving precise ignition timing to utilize most of the heat release.
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This document provides an overview of fuel cell technologies. It discusses how fuel cells work by directly converting chemical energy to electrical energy through electrochemical reactions, avoiding combustion. This allows for higher efficiencies than combustion-based power generation. It also summarizes the key components of a fuel cell and different fuel cell configurations. The document focuses on solid oxide fuel cells (SOFCs) and their potential for stationary power generation applications due to their high operating temperatures.
Transonic novel fuel injection system engine.pdfCSA Welfare
The document discusses Transonic Combustion's novel fuel injection technology called TSCi. TSCi injects fuel into the engine cylinder in a supercritical state, which allows for more precise control over ignition timing and location of combustion. This enables significantly higher efficiency combustion compared to traditional engines. Specifically:
1) TSCi raises the fuel to a supercritical state before injection, allowing for rapid mixing with air and spontaneous ignition in multiple locations for high heat release and efficiency.
2) Testing has shown promise, with one modified gasoline engine achieving 98 mpg at 50 mph.
3) By controlling ignition timing to occur after top dead center, all work from combustion produces positive work on the piston,
The document is a seminar report on HCCI and CAI engines presented by Saurabh Y. Joshi. It discusses the basics of HCCI and CAI, including the working principles of HCCI engines. CAI can be used in gasoline engines with high compression ratios. Methods to achieve CAI include using EGR, increasing compression ratio, and adjusting intake conditions. CAI engines have very low NOx emissions but higher HC and CO emissions than SI engines. While HCCI/CAI engines provide improved efficiency, challenges remain around combustion control and cold starting. Ongoing research continues to address these challenges.
In this investigation, Cashew nut shell liquid (CNSL) biodiesel, hydrogen and
ethanol (BHE) mixtures remained verified in a single cylinder direct-injection diesel
engine to examine the recital plus discharge features of the engine. The engine stayed
verified at supreme force and rapidity of 1500 rpm. The ethanol remained
supplemented 5%, 10% and 15% correspondingly through enhanced CNSL as well as
hydrogen functioned twin fuel engine. The consequences designate that while
associated through well-ordered diesel and biodiesel-hydrogen process, the recital
and discharge features of ethanol mixtures obligates upgraded. The brake thermal
efficiency upsurges somewhat through 10% ethanol mixtures and nope noteworthy
enhancement by advanced ethanol mixtures. The exhaust gas temperature and NOx
release augmented by 10% ethanol accumulation. Through greater proportion of
ethanol in the biodiesel hydrogen (BH) mixtures the HC, CO releases might upsurge.
However the routine of 10% ethanol might diminish the HC and CO releases
equally. Overall the BHE mixtures ensure greater NOx discharges, associated by
biodiesel and diesel energy. Throughout the BHE mixtures offers lesser HC, CO, as
well as greater NOx release associated through the well-ordered diesel fuel.
Nevertheless the embellishments of added ethanol thru BH mixtures require no
substantial enhancement in the recital discharge and stages
Similar to Performance HCCI Ethanol Fuelled Engine (20)
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Predicting Fuel Performance for Future HCCI Engines
a b a a
Vi H. Rapp , William J. Cannella , J.-Y. Chen & Robert W. Dibble
a
Department of Mechanical Engineering, University of California–Berkeley, Berkeley,
California, USA
b
Chevron Energy Technology Company, Richmond, California, USA
Accepted author version posted online: 04 Dec 2012.
To cite this article: Vi H. Rapp , William J. Cannella , J.-Y. Chen & Robert W. Dibble (2012): Predicting Fuel Performance for
Future HCCI Engines, Combustion Science and Technology, DOI:10.1080/00102202.2012.750309
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2. ACCEPTED MANUSCRIPT
Predicting Fuel Performance for Future HCCI Engines
Vi H. Rapp1,*, William J. Cannella2, J.-Y. Chen1, Robert W. Dibble1
1
Department of Mechanical Engineering, University of California–Berkeley, Berkeley,
California, USA, 2Chevron Energy Technology Company, Richmond, California, USA
*Corresponding author: E-mail: vhrapp@berkeley.edu
Downloaded by [Universiti Teknologi Malaysia] at 20:55 11 January 2013
Abstract
The purpose of this research is to investigate the impact of fuel composition on auto-
ignition in HCCI engines in order to develop a future metric for predicting fuel
performance in future HCCI engine technology. A single-cylinder, variable compression
ratio engine operating as an HCCI engine was used to test reference fuels and gasoline
blends with Octane numbers (ON) ranging from 60-88. Correlations between fuel
composition, ON, and two existing methods for predicting fuel auto-ignition in HCCI
engines (Kalghatgi’s Octane Index and Shibata and Urushihara’s HCCI Index) are
investigated. Results show that Octane Index and HCCI Index poorly predict the impact
of fuel composition on auto-ignition for fuels with the same ON. The effect of ethanol in
delaying auto-ignition depends on the composition of the original gasoline blend; the
same is true for the addition of naphthenes. Low temperature heat release (LTHR)
correlates well with auto-ignition for gasoline fuels exhibiting LTHR.
KEYWORDS: Auto-ignition, Homogenous charge compression-ignition (HCCI), Fuel
composition
INTRODUCTION
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Increasing concern with climate change has encouraged the development of alternative
fuels and advanced engine technologies that improve efficiency and reduce CO2
emissions. Homogeneous charge compression ignition (HCCI) engines offer the potential
for Diesel-like efficiencies and low nitrogen oxide emissions compared with conventional
gasoline and Diesel engines. HCCI engines also offer fuel flexibility as they can operate
using a wide variety of fuels such as Diesel, gasoline, and alternative fuels (Thring, 1989;
Fuhs, 2008). In the early twentieth century, Weiss and Mietz developed the first HCCI-
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like combustion engine, called the hot-bulb engine (Erlandsson, 2002). The hot-bulb
engine offered a simple and durable design that had brake thermal efficiencies
comparable to contemporary Diesel engines. Later, in 1979, Onishi et al. (1979)
published the first research on a gasoline-fueled HCCI engine. The two-stroke gasoline
engine, using a process dubbed Active Thermo-Atmosphere Combustion (ATAC) by the
authors, increased fuel economy and decreased exhaust emissions at part-throttle
operation.
In 1983, Najt and Foster (1983) achieved compression ignition homogenous charge
(CIHC) combustion in a four-stroke gasoline engine. Using the same engine as Najt and
Foster, Thring (1989) studied the effects of exhaust gas recirculation, intake temperature,
and compression ratio; he was also the first to use the acronym HCCI. Seven years after
Thring, the first research burning Diesel fuel in an HCCI engine appeared (Gray and
Ryan, 1997) and led to research testing other fuels, such as alcohols (Oakley et al., 2001),
hydrogen (Shudo and Ono, 2002), natural gas (Christensen, Johansson and Einewall,
1997; Hiltner et al., 2000; Olsson et al., 2002; Stanglmaier, Ryan and Souder, 2001),
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propane(Au et al., 2001; Flowers et al., 2001), and many fuel blends with additives (Eng,
Leppard and Sloane, 2003; Yao, Zheng and Liu, 2009)
Although HCCI engines offer fuel flexibility and a solution for meeting new, strict
pollution requirements, HCCI engines have a limited load range and cannot support high
load demands required by automobiles. Hybrid HCCI engines, such as SI-HCCI (Zhang,
Xie and Zhao, 2009; Koopmans et al., 2003), HCCI-DI (Canova et al., 2007; Helmantel
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and Denbratt, 2004), or HCCI-electric(Wu and Zhang, 2012), offer a solution for
reducing emissions and increasing the load operating range. As HCCI engine technology
becomes more widely used in automotive technology, developing fuels to support hybrid
HCCI engines will become increasingly important.
Conventional methods for quantifying fuel auto-ignition, such as Research Octane
Number (RON), Motor Octane Number (MON), Octane Number (ON = ½RON +
½MON) and Cetane Number, poorly predict auto-ignition in HCCI engines (Kalghatgi,
2005; Shibata and Urushihara, 2007). Kalghatgi (2005) developed an Octane Index (OI)
for measuring the auto-ignition or anti-knock quality of a practical fuel at different
operating conditions. The OI, not to be confused with ON, is defined as,
OI = (1 K)RON + (K)MON, (1)
where K is a parameter specified by engine operating conditions. Although the OI may
be applicable for HCCI operation (Kalghatgi, 2005), the OI does not fully describe the
impact of fuel composition on auto-ignition in HCCI engines.
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Shibata and Urushihara (2007) investigated the impact of fuel composition on auto-
ignition in HCCI engines and introduced three HCCI Indices. While all three HCCI
Indices predict auto-ignition similarly, the relative HCCI Index (HIrel) predicts auto-
ignition of fuels using the fuel composition and MON (Shibata and Urushihara, 2007).
The HIrel is defined as,
HI rel = MON + α(nP) +β(iP)
(2)
(O) δ(A) + (OX),
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where nP is the percent n-paraffins by volume, iP is the percentiso-paraffins by volume,
O is the percent olefins and cycloalkanes by volume, A is the percent aromatics by
volume, OX is the percent oxygenates by volume, and α, β, γ, δ, and ε are temperature
dependent parameters.
In this paper, the capability of two existing methods (the OI and the HIrel) for predicting
the impact of fuel composition on auto-ignition in HCCI engines is investigated and
correlations between fuel composition and auto-ignition of fuels in a HCCI engine are
explored. Fuels tested consist of following five different blends:
1. Primary reference fuels (PRF):blends of isooctane and n-heptane
2. Toluene reference fuels (TRF): PRF fuels blended with toluene
3. Ethanol reference fuels(E-PRF): PRF fuels blended with Ethanol
4. Gasoline blendstocks
5. Gasoline blendstocks with different pure compounds added (“additives”)
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Following this Introduction, the instrumentation and experimental design are described.
Next, results and discussions are presented. Last, future work is suggested and
conclusions are drawn.
MATERIALS AND METHODS
Engine and Fuel Specifications
Similar to previous metrics for predicting fuel auto-ignition, such as RON and MON
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(ASTM RON Standard, 2011; ASTM MON Standard, 2011), experiments were
conducted using a variable compression ratio, single cylinder cooperative fuel research
(CFR) engine operating in HCCI mode. Engine specifications and operating conditions
are listed in Table 1. The engine was preheated by operating in spark-ignition mode
under stoichiometric conditions. Once the coolant temperature reached 80°C, the
equivalence ratio was decreased to =0.33 ( =3.0). Next, the compression ratio (CR)
was slowly increased until stable auto-ignition (no misfiring) occurred. The lowest CR
limit was determined by decreasing the CR until HCCI operation became unstable. The
highest CR limit for each fuel was determined by increasing the CR until the in-cylinder
pressure exceeded 50 bar (a limit to safe guard the mechanical integrity of CFR engine)
or the ringing intensity became too great (Eng, 2002). For each experiment, equivalence
ratio was held constant at φ=0.33 (λ=3.0). Data were taken at various compression ratios
between the lowest and the highest limits. For a fixed CR, 300 thermodynamic cycles
(each cycle with 720 CAD) of in-cylinder pressure data were collected along with
exhaust emissions before the catalytic converter.
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The effects of fuel composition on auto-ignition timing n HCCI engines, measured by
CA50 (the crank angle degree at which 50% of the cumulative heat has been
released),was explored by testing twenty different fuel blends at an engine intake
temperature of 150°C and one fuel, PRF70, at intake temperatures of 70°C, 115°C, and
150°C. Of the twenty fuels, eight fuels were reference fuel blends. The reference fuel
blends consisted of PRF60, PRF70, PRF75, PRF85, PRF88, TRF70, S70, and E-PRF70.
For primary reference fuels (PRF), the number following "PRF" is the RON, MON, and
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percent isooctane by volume. TRF70 (46% n-heptane and 54% toluene, by volume) has a
calculated RON of 70.5and MON of 63.5, which were calculated using a linear-by-
volume blending equation created by Morgan et al.(2010). For S70 (64% isooctane, 31%
n-heptane, and 5% toluene by volume) the RON and MON were measured, by Chevron,
as 70.5and 69.6, respectively. A RON of 69.5 and MON of 68.6 were calculated for E-
PRF70 (64% isooctane, 31% n-heptane, and 5% ethanol by volume) using the blending
RON and blending MON values from Anderson et al.(2010). A summary of the reference
fuel blend compositions, RON, and MON are given in Table 2.
Two different base gasolines, typically used in U.S. gasoline blends, were provided by
Chevron, labeled G1 and G2. Hydrocarbon class information and the RON and MON of
the base gasolines are provided in Table 3. The base gasoline fuels were blended with
different “additives”: n-heptane, ethanol, cycloparaffins, and aromatics. RON and MON
for the gasoline fuel blends are listed in Table 4along with the type of additive. Fuels
with a calculated RON and MON were determined using the blending RON and blending
MON of the additive.
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Determining Octane Index, Relative HCCI Index, And Heat Release
The K factor for the OI, shown in Eq. (1), is a function of the in-cylinder temperature
when the in-cylinder pressure, during the compression stroke, reaches 15 bar (Tcomp,15bar)
(Kalghatgi, 2005). The K factor is computed using the following equations:
K = 0.0426 (Tcomp,15bar ) 35.2 if Tcomp,15bar 825 K , (3)
or
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0.0056(Tcomp,15bar ) 4.68 if Tcomp,15bar 825K . (4)
For the UC Berkeley CFR engine operating at 600 RPM with an intake temperature of
150°C, Tcomp,15bar is estimated to be 780K, yielding K=-0.312 using Eq. (4) (Kalghatgi,
2005).
Because the OI was used to develop the HIrel, the temperature dependent constants for the
HIrel, shown in Eq.(2), are also functions of Tcomp,15bar. For Tcomp,15bar = 780K, Shibata and
Urushihara list values for the constants as follows (Shibata and Urushihara, 2007):α = -
0.487, β= -0.380, γ= -0.246, δ= -0.222, and ε=0.049. These constants were determined
using a similar method as the K factor in the Octane Index.
In addition to developing the relative HCCI Index, Shibata et al. (2005) suggested that
low temperature heat release (LTHR) might correlate with auto-ignition better than high
temperature heat release (HTHR). LTHR is defined as total heat release (Killingsworth,
2007) d from combustion at in-cylinder temperatures less than 1000K while HTHR is
total heat released from combustion at in-cylinder temperatures greater than 1000K. In
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their study, correlations between auto-ignition and LTHR were investigated by dividing
LTHR by HTHR for each fuel, yielding a heat release ratio. In this paper, the net heat
release per crank angle degree (dQ/dθ) was determined using the first law of
thermodynamics (Heywood, 1988; Stone, 1999),
dQ γ dV 1 dp
= p + V (5)
dθ γ 1 dθ γ 1 dθ
where γ is the specific heat ratio, p is pressure, and V is volume. To avoid numerically
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differentiating the discrete pressure measurements and amplifying signal noise, Eq. (6)
was be rewritten as,
dQ 1 d(pV) dV
= +p (6)
dθ γ 1 dθ dθ'
and the cumulative net heat release, Qi, was computed as a finite sum instead of a
continuous integral using (Killingsworth, 2007),
i
1
Qi [pi Vi p 0 V0 ] p j ( V ) j, (7)
1 j 0
where i and j imply a discrete measurement of pressure and volume at a given crank
angle degree. The specific heat ratio, γ, was assumed to be constant during compression
and expansion. A linear fit between the compression γ and expansionγ was used to
calculate dQ/dθ during combustion. Figure 1 shows the inflection points in the heat
release rate that were used to distinguish between LTHR and HTHR. We assumed that
LTHR began when the heat release rate was greater than zero and that HTHR ended
when the heat release rate dropped below zero.
Measurement Instrumentation
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In-cylinder pressure was measured using a 6052B Kistler piezoelectric pressure
transducer in conjunction with a 5044A Kistler charge amplifier and was recorded every
0.1 crank angle (CA) degree. The cylinder pressure transducer was mounted in the
cylinder head. Intake pressure was measured using a 4045A5 Kistler piezoresistive
pressure transducer in conjunction with a 4643 Kistler amplifier module. Crank angle
position was determined using an optical encoder, while an electric motor, controlled by
an ABB variable speed frequency drive, controlled the engine speed. A Motec M4 ECU
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(Engine Control Unit) controlled injection timing, injection pulse width, and injection
duty cycle. Before collecting data for each experiment, the engine was run until the
coolant temperature reached 80°C and combustion became steady. A Horiba analyzer
was used for measuring exhaust gases (CO, CO2, O2, unburned hydrocarbons (UHC), and
nitrogen oxides (NOx)). For lean complete combustion, emissions measurements were
used to deduce the normalized air-fuel ratio using,
nc [O 2 ]
1 , (8)
nH no [CO 2 ]
nc
4 2
where nc is the number of carbon atoms in the fuel, nH is the number of hydrogen atoms
in the fuel, nO is the number of oxygen atoms in the fuel, [O2] is the percent oxygen
measured in the emissions, and [CO2] is the percent carbon dioxide measured in the
emissions. The number of carbon, hydrogen, and oxygen atoms were estimated using the
fuel composition. The uncertainty in the normalized air-fuel ratio is approximately± 0.05.
EFFECTS OF FUEL COMPOSITION ON AUTO-IGNITION
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The following results demonstrate the impact of fuel composition on auto-ignition in
HCCI engines. First, auto-ignition timing, measured by CA50, of each fuel at various
compression ratios is presented. Second, the Octane Index (OI) is compared with
experimental data. Third, the relative HCCI Index (HIrel) is compared with experimental
data. Fourth, correlations between fuel composition, auto-ignition and low temperature
heat release (LTHR) are investigated.
Auto-Ignition Timing (Ca50)
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The effects of fuel composition on auto-ignition were first investigated by measuring the
auto-ignition timing (CA50) of each fuel at various compression ratios. Figure 2 plots
CA50 versus CR for the twenty fuels tested showing that fuel blends with similar ON do
not always auto-ignite at the same CR, which is consistent with previous research (Liu et
al., 2009). The uncertainty in CA50 and CR was calculated to be ±0.5 and ±0.1,
respectively (Taylor, 1997). For example, tested fuels with ON~70 are: PRF70, S70,
TRF70, E-PRF70, G2, and G1-H. As seen in Fig. 2, PRF70, S70, and G1-H auto-ignite
at similar CR values. However, TRF70 auto-ignites half a CR higher than PRF70, E-
PRF70 auto-ignites a full CR higher than PRF70, and G2 auto-ignites three CRs higher
than PRF70. The results also suggest that ethanol inhibits auto-ignition more than toluene
as S70 auto-ignites at the same CR as PRF70, while E-PRF70 auto-ignites a full CR
higher than PRF70 and half a CR higher than TRF70.
The results also show adding the same amount of ethanol, 10% by volume, to G1
(RON=87) and G2 (RON=70) does not have the same effect on auto-ignition. As shown
in Fig. 2, G1-E2 (RON=90) auto-ignites about one CR higher than G1, while G2-E2
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(RON=78) auto-ignites three CRs higher than G2. Like ethanol, the naphthene, N1,
affects auto-ignition of G2 more than G1; G2-N1 (RON=N/A) auto-ignites about half a
CR higher than G2 and G1-N1 (RON=86) auto-ignites at about the same CR as G1.
The Octane Index (Oi)
Although the OI was developed for predicting anti-knock qualities of practical fuels in
spark ignited engines, Kalghatgi (Kalghatgi, 2005) suggests that the OI can be used for
predicting auto-ignition of fuels in an HCCI engine. For the CFR engine running at the
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same inlet temperature, inlet pressure, and RPM, the compression ratio when CA50=6
deg ATDC is used for quantifying the fuel’s propensity of autoignition. This operating
condition was chosen because data was successfully collected for all fuels when CA50=6
deg ATDC.Figure3 shows the relationship between OI and compression ratio when a
CA50=6 deg ATDC for nineteen of the twenty fuels tested. The OI could not be
calculated for G2-N1 because RON and MON were unavailable. The OI accurately
predicts auto-ignition of the primary reference fuel (PRF) blends, agreeing well with
previous results (Liu et al., 2009; Yao, Zheng and Liu, 2009). These results were
expected because for PRF blends OI = ON. The OI poorly predicts auto-ignition of some
fuels with the same ON. For example, the OI predicts S70, E-PRF70, and G2 will have
similar auto-ignition characteristics; however, E-PRF70 auto-ignites almost one CR
higher than S70 and G2 auto-ignites almost two CR higher than S70.
Additionally, the OI poorly predicts auto-ignition of fuels containing naphthenes. The OI
predicts G1-N1 (RON=86, MON=79) and G1-N2 (RON=87, MON=81) having similar
auto-ignition characteristics, but the experimental results show G1-N2 auto-igniting one
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CR higher than G1-N1. The OI also predicts G1-A2 (RON=91, MON=82) auto-igniting
after G1-N2, but the experimental results show G1-N2 auto-igniting one CR higher than
G1-A2. Although the OI correlates with the RON and MON, it is not sufficient for
predicting auto-ignition of fuels with similar ON.
The Relative HCCI Index (Hirel)
The HIrel, introduced by Shibata and Urushihara (2007), is the first published research for
predicting auto-ignition of fuels in an HCCI engine using the fuel composition and MON.
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Like the OI, the HIrel predicts auto-ignition order of fuels; fuels with higher HIrel require
higher CR for auto-ignition (i.e. more difficult to auto-ignite). Figure 4 shows the
relationship between HIrel and CR when CA50=6 deg ATDC for nineteen of the twenty
fuels tested. The HIrel could not be calculated for G2-N1 because MON was unavailable.
The HIrel accurately predicts auto-ignition of some PRF blends, and some gasoline fuels
blended with ethanol. However, the HIrel does not accurately predict ignition order of
some fuels with similar ON. For example, PRF70, S70, G1-H, TRF70, E-PRF70, and G2
have the same HIrel, but experimental results show TRF70, E-PRF70, and G2 auto-
igniting at different CRs than PRF70, S70, and G1-H and G2-E2 auto-igniting at different
CR’s than PRF 75.
The HIrel also poorly predicts auto-ignition of fuel blends containing different aromatics.
The HIrel assumes that fuels containing different aromatic compounds at the same
concentration and approximately same MON will have similar effects on auto-ignition, as
all aromatics are grouped together in Eq. (2). Fig. 4 shows that different aromatics at the
same concentration and approximately same MON can have different effects on auto-
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ignition. For example, G1-A1 has a lower HIrel than G1-A2, but the experimental results
show G1-A1 auto-igniting half a CR higher than G1-A2. Since naphthenes are not
included in Eq. (2), and if their effects are assumed to be the same, the HIrel relation
would predict G1-N1 and G1-N2 having similar effects on auto-ignition (Shibata and
Urushihara, 2007). However, Fig. 4 shows G1-N1 auto-igniting one CR lower than G1-
N2. It should be noted that temperature dependent constants used for computing HIrel
were developed using the K factor in the OI. Therefore, the results from the HIrel were
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expected to be similar to the results from the OI.
Low Temperature Heat Release
Previous research (Shibata et al., 2005) suggests low temperature heat release (LTHR)
may correlate with auto-ignition better than high temperature heat release (HTHR).
Figures 5 and 6 show the dependence of the heat release ratio (the ratio of average LTHR
to HTHR) on CR. For gasoline fuels, the heat release ratio decreases almost linearly as
CR (when CA50=6 deg ATDC) increases from 9 to 15 (see Fig. 5). Gasoline fuels with
the same ON show different heat release ratios and correlate well with CR. For example,
G1-H auto-ignites almost 2 CRs lower than G2 and the heat release ratio predicts G1-H
has about 3% less LTHR than G2. The heat release ratio also suggests gasoline fuels with
more LTHR will auto-ignite at lower CR, agreeing with previous research (Shibata et al.,
2005). For gasoline fuels auto-igniting at CRs greater than 15, no LTHR was detectable
using our instrumentation.
Figure 6 shows reference fuels with similar ON (PRF70, S70, TRF70, and E-PRF70)
have similar amounts of LTHR, suggesting the reference fuels should auto-ignite at
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similar CRs. However, these reference fuels do not auto-ignite at the same CR. For
example, ethanol in E-PRF70 was expected to suppress LTHR. Instead, E-PRF70 shows
similar amounts of LTHR as PRF70 while auto-igniting at the same CR as PRF75. The
results suggest that the addition of Ethanol makes auto-ignition more difficult, but
ethanol does not necessarily suppress LTHR. One possible explanation for E-PRF70
exhibiting the same LTHR as PRF70 is that the 31% n-heptane in E-PRF70 may promote
more LTHR than ethanol suppresses. For fuels exhibiting decreasingly low amounts of
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LTHR, a water-cooled pressure transducers may provide better resolution (Sjoberg and
Dec, 2003; Stone, 1999).
Overall, the results show that LTHR correlates well with auto-ignition of gasoline blends
exhibiting LTHR, but does not correlate well with reference fuel blends. This suggests
that reference fuels for spark-ignited engines may not be appropriate reference fuels for
HCCI engines.
CONCLUSIONS
In this paper, we investigated the impact of fuel composition on auto-ignition in HCCI
engines in order to develop a future metric for predicting fuel performance in future
HCCI engine technology. The following conclusions were derived:
• For a fixed intake temperature, intake pressure, and equivalence ratio, fuels with
the same Octane Number (ON) do not auto-ignite at similar compression ratios (CR).
Additionally, the effect of ethanol (and naphthene) in delaying auto-ignition is dependent
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on the gasoline blendstocks.
The Octane Index and relative HCCI Index correlate well with auto-ignition of primary
reference fuel but poorly predict auto-ignition of gasoline fuel blends containing
naphthenes, aromatics, and ethanol.
Low temperature heat release (LTHR) correlates well with auto-ignition for gasoline
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fuels with measurable LTHR but does not correlate well for reference fuels. The results
suggest that reference fuels may not be appropriate for describing fuel performance in
HCCI engines. For fuels auto-igniting at CRs greater than 15, LTHR could not be
detected.
More than one metric may be required for predicting auto-ignition. For gasoline fuels that
exhibit LTHR, LTHR better predicts auto-ignition order than Octane Index and the
Relative HCCI Index. For fuels that do not exhibit LTHR, a different metric is needed.
To further advance development of a future metric for predicting fuel performance in
future HCCI engine technology, we recommend that more fuel blends containing linear
amounts of toluene, ethanol, and various aromatics, by volume, should be explored to
help identify reference fuels for a standard HCCI number. Additionally, different test
conditions, such higher RPM and lower intake temperatures, should be explored further
for the fuels used in this research. Trends established at different operating conditions
could be used with trends found in this paper to establish a standard HCCI metric.
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ACKNOWLEDGEMENTS
Research conducted at the University of California, Berkeley was supported by the
Chevron Corporation. The authors also wish to acknowledge the assistance of T.
Dillstrom, A. Van Blarigan, and M. Wissink in conducting experimental measurements.
ABBREVIATIONS
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ATAC Active Thermo-Atmosphere Combustion
ATDC After top dead center
CA50 Crank angle at which 50% of heat has been released
CAD Crank angle degree
CFR Cooperative Fuel Research
CIHC Compression ignition homogenous charge
CR Compression ratio
DI Direct Injection
E-PRF Ethanol Reference Fuel
ECU Engine control unit
HCCI Homogenous Charge Compression Ignition
HIrel, Relative HCCI Index
HTHR High temperature heat release
LTHR Low temperature heat release
MON Motor Octane Number
OI Octane Index
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ON Octane Number
PRF Primary Reference Fuel
RON Research Octane Number
SI Spark Ignition
TRF Toluene Reference Fuel
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REFERENCES
Anderson, J.E., Kramer, U., Mueller, S.A., and Wallington, T.J. 2010. Octane numbers of
ethanol and methanol gasoline blends estimated from molar concentrations. Energy and
Fuels, 24, 6576-6585.
ASTM MON Standard 2011. D2700-11, Standard test method for motor octane number
of spark-ignition engine fuel. ASTM International West Conshohocken, PA,
DOI:10.1520/D2700-11, www.astm.org.
ASTM RON Standard 2011. D2699-11, Standard test method for research octane
number of spark-ignition engine fuel. ASTM International West Conshohocken, PA,
DOI:10.1520/D2699-11, www.astm.org.
Au, M.Y., Girard, J.W., Dibble, R.W., Flowers, D., Aceves, S.M., Martinez-Frias, J., Ray
Smith, C.S., and Mass, U. 2001. 1.9-liter four cylinder HCCI engine operation with
exhaust gas recirculation. SAE Technical Paper 2001-01-1894.
Canova, M., Chiara, F., Cowgill, J., Midlam-Mohler, S., Guezennec, Y., and Rizzoni, G.
2007. Experimental Characterization of Mixed-Mode HCCI/DI Combustion on a
Common Rail Diesel Engine. SAE Technical Paper 2007-24-0085.
ACCEPTED MANUSCRIPT
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19. ACCEPTED MANUSCRIPT
Christensen, M., Johansson, B., and Einewall, P. 1997. Homogeneous charge
compression ignition (HCCI) using isooctane, ethanol and natural gas - a comparison
with spark-ignition operation. SAE Technical Paper 972874.
Eng, J.A. 2002. Characterization of pressure waves in HCCI combustion. SAE Technical
Paper 2002-01-2859.
Eng, J., Leppard, W., and Sloane, T. 2003. The effect of di-tertiary butyl peroxide
(DTBP) addition to gasoline on HCCI combustion. SAE Technical Paper 2003-01-3170.
Downloaded by [Universiti Teknologi Malaysia] at 20:55 11 January 2013
Erlandsson, O. 2002. Early Swedish hot-bulb engines - Efficiency and performance
compared to contemporary gasoline and diese engines. SAE Technical Paper 2002-01-
0115.
Flowers, D., Aceves, S.M., Martinez-Frias, J., Smith, J.R., Au, M.Y., Girard, J.W., and
Dibble, R.W. 2001. Operation of a four-cylinder 1.9L propane-fueled homogeneous
charge compression ignition engine: Basic operating characteristics and cylinder-to-
cylinder effects. SAE Technical Paper 2001-01-1895.
Fuhs, A. 2008. Hybrid Vehicles and the Future of Personal Transport. Boca Raton: CRC
Press.
Gray, A.W., and Ryan, T.W. 1997. Homogeneous charge com- pression ignition (HCCI)
of diesel fuel. SAE Technical Paper 971676.
Helmantel, A., and Denbratt, I. 2004. HCCI operation of a passenger car common rail DI
Diesel engine with early injection of Conventional Diesel fuel. SAE Technical Paper
2004-01-0935.
Heywood, J.B. 1988. Internal Combustion Engine Fundamentals. McGraw-Hill, Inc.
Hiltner, J., Agama, R., Mauss, F., Johansson, B., and Christensen, M. 2000. HCCI
ACCEPTED MANUSCRIPT
18
20. ACCEPTED MANUSCRIPT
operation with natural gas: Fuel composition implications. Proceedings of the 2000
ASME International Combustion Engine Fall Technical Conference., 35(2), 11-19.
Kalghatgi, G.T. 2005. Auto-Ignition Quality of Practical Fuels and Implications for Fuel
Requirements of Future SI and HCCI Engines. SAE Technical Paper 2005-01-0239.
Killingsworth, N.J. 2007. HCCI Engine Control and Optimization. University of
California, San Diego.
Koopmans, L., Strom, H., Ludgren, S., Baklund, O., and Denbratt, I. 2003.
Downloaded by [Universiti Teknologi Malaysia] at 20:55 11 January 2013
Demonstrating a SI-HCCI-SI Mode Change on a Volvo 5-Cylinder Electronic Valve
Control Engine. SAE Technical Paper 2003-01-0753.
Liu, H., Yao, M., Zhang, B. and Zheng, Z. 2009. Influence of fuel and operating
conditions on combustion characteristics of a homogeneous charge compression ignition
engine. Energy and Fuels, 23, 1422-1430.
Morgan, N., Smallbone, A., Bhave, A., Kraft, M., Cracknell, R., and Kalghatgi, G. 2010.
Mapping surrogate gasoline compositions into RON/MON space. Combustion and Flame,
157, 1122-1131.
Najt, P.M., and Foster, D.E. 1983. Compression-ignited homogeneous charge combustion.
SAE Technical Paper 830264.
Noguchi, M., Tanaka, Y., Tanaka, T., and Takeuchi, Y. 1979. A study on gasoline engine
combustion by observation of intermediate reactive products during combustion. SAE
Technical Paper 790840.
Oakley, A., Zhao, H., Ma, T., and Ladommatos, N. 2001. Dilution effects on the
controlled auto-ignition (CAI) combustion of hydrocarbon and alcohol fuels. SAE
Technical Paper 2001-01-3606.
ACCEPTED MANUSCRIPT
19
21. ACCEPTED MANUSCRIPT
Olsson, J.-O., Tunestal, P., Johansson, B., Fiveland, S., Rey Agama, M.W., and Assanis,
D. 2002. Compression ratio influence on maximum load of a natural gas fueled HCCI
engine. SAE Technical Paper 2002-01-0111.
Onishi, S., Jo, S.H., Shoda, K., Jo, P.D., and Kato, S. 1979. Active thermo-atmosphere
combustion (ATAC) - a new combustion process for internal combus- tion engines. SAE
Technical Paper 790501.
Shibata, G., Oyama, K., Urushihara, T., and Nakano, T. 2005. Correlation of Low
Downloaded by [Universiti Teknologi Malaysia] at 20:55 11 January 2013
Temperature Heat Release With Fuel Composition and HCCI Engine Combustion. SAE
Technical Paper 2005-01-0138.
Shibata, G., and Urushihara, T. 2007. Auto-Ignition Characteristics of Hydrocarbons and
Development of HCCI Fuel Index. SAE Technical Paper 2007-01-0220.
Shudo, T., and Ono, Y. 2002. HCCI combustion of hydrogen, carbon monoxide and
dimethyl ether. SAE Technical Paper 2002-01-0112.
Sjoberg, M., and Dec, J.E. 2003. Combined Effects of Fuel-Type and Engine Speed on
Intake Temperature Requirements and Completeness of Bulk-Gas Reactions for HCCI
Combustion. SAE Technical Paper 2003-01-3173.
Stanglmaier, R.H., Ryan, T.W., and Souder, J.S. 2001. HCCI operation of a dual-fuel
natural gas engine for improved fuel efficiency and ultra-low NOx emissions at low to
moderate engine loads. SAE Technical Paper 2001-01-1897.
Stone, R. 1999. Introduction to internal combustion engines, 3rd ed., Warrendale:
Society of Automotive Engineers, Inc.
Taylor, J.R. 1997. An Introduction to Error Analysis: The Study of Uncertainties in
Physical Measurements, 2nd ed., University Science Books Sausalito, California.
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22. ACCEPTED MANUSCRIPT
Thring, R.H. 1989. Homogeneous-charge compression ignition (HCCI) engines. SAE
Technical Paper 892068.
Wu, J., and Zhang, H. 2012. Analysis on Application of HCCI Technology for Hybrid
Electric Vehicles. Applied Mechanics and Materials, 128-129, 803-806.
Yao, M., Zheng, S., and Liu, H. 2009. Progress and recent trends in homogenous charge
compression ignition (HCCI) engines. Progress in Energy and Combustion Science, 35,
398-437.
Downloaded by [Universiti Teknologi Malaysia] at 20:55 11 January 2013
Zhang, Y., Xie, H., and Zhao, H. 2009. Investigation of SI-HCCI Hybrid Combustion and
Control Strategies for Combustion Mode Switching in a Four- Stroke Gasoline Engine.
Combustion Science and Technology, 181(5), 782-799.
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Table 1. CFR engine specifications
Displacement 0.616 L
Stroke 114.3 mm
Bore 82.8 mm
Connecting Rod 254 mm
Engine Speed 600 RPM
Coolant Temperature 80°C ±1°C
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Intake Pressure 1.035 bar
Intake Temperature 150°C ±1°C
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Table 2. Reference fuel blend compositions by volume percent with RON and MON
Fuel Name % iso-ocatne % n-heptane % Toluene % Ethanol RON MON
PRF 60 60 40 0 0 60 60
PRF 70 70 30 0 0 70 70
PRF 75 75 25 0 0 75 75
PRF 85 85 15 0 0 85 85
PRF 88 88 12 0 0 88 88
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TRF 70* 0 46 54 0 70.5 63.5
S 70 64 31 5 0 70.5 69.6
E-PRF 70+ 64 31 0 5 69.5 68.6
n-heptane 0 100 0 0 0 0
*
RON and MON were calculated using method described by Morgan et al. (2010).
+
RON and MON were calculated using bRON and bMON values from Anderson et al.
(2010).
RON and MON of remaining fuels were assumed.
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Table 3. Base gasoline hydrocarbon class information (percent by volume)
Fuel %N- %Iso- %Ole %Cycloparaffins %Arom RO MON
Name Paraffins Paraffins fins atics N
G1 14.2 44.9 5.2 9.8 25.9 87 80
G2 4.7 48.2 0.3 34.4 12.4 70 65
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Table 4. Gasoline fuel blend information
Fuel Name Additive RON MON
G1-H N-heptane 70b 65b
G2-H N-heptane 60a 55a
G1-E1 Ethanol 93a 84a
G1-E2 Ethanol 90a 82a
G2-E2 Ethanol 78a 68a
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G1-A1 Toluene 91a 82a
G1-A2 O-Xylene 91b 82b
G1-N1 Methylcyclohexane 86b 79b
G2-N1 Methylcyclohexane N/A N/A
G1-N2 Cyclohexane 87b 81b
“N/A” implies not available
a
RON or MON was estimated
b
RON or MON was provided by Chevron
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Figure 1. Distinction between low temperature heat release (LTHR) from low
temperature combustion and high temperature heat release (HTHR) from high
temperature combustion.
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Figure 2. Auto-ignition in HCCI engines varies almost linearly with compression ratio.
Fuels with the same octane number (ON), such as G2 and G1, do not auto-ignite at the
same compression ratios. Error bars are suppressed for visibility. Error in CA50 is
typically ± 0.5 of the shown value.
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Figure 3. The Octane Index poorly predicts auto-ignition fuels with similar Octane
Number (ON) but shows an almost linear relationship (R2=0.90) with compression ratio
for all fuel blends.
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Figure 4. HCCI index correlates well with primary reference fuel blends but poorly
predicts auto-ignition of fuel blends containing ethanol, aromatics, or naphthenes.
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Figure 5. For gasoline fuels, the ratio of LTHR to HTHR shows an almost linear decrease
with the compression ratio at a CA50=6 deg ATDC.
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Figure 6. Reference fuels with the same ON have similar amounts of LTHR even though
they auto-ignite at different compression ratios. PRF blends decrease with compression
ratio at a CA50=6 deg ATDC.
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