R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793787 | P a g eExperimental Investigation on Comparison of PerformanceExhaust Emission and Characteristics using Diesel and Bio Dieselin Conventional Diesel Engine and Thermal Barrier Coated LHREngineR. Lokanatham*, Prof. K. Ravindranath***Research Scholar, S.V. University, Tirupati, A.P.**Formerly Principal, S.V. College of Engineering, Tirupati, A.P.ABSTRACTBiodiesel is a clean- burning dieselreplacement fuel made from natural, renewablesources such as new and used vegetable oils andanimals fats. The biodiesel was characterized bydetermining its density results in combustionproblems and hence it is proposed to used bio-diesel in Low Heat Rejection (LHR) dieselengine to obtain efficiency. In this work biodieselfrom Jatropha oil called as Jatropha Oil MethylEster (JOME) was used as sole fuel inconventional diesel engine and LHR directinjection (DI) diesel engine. The low heatrejection engine was developed with uniformceramic coating of combustion chamber(includes piston crown, cylinder head, valvesand cylinder liner) by Partially StabilizedZirconia (PSZ) thickness of 0.5 mm thickness.The experimental investigation was carried outin a single cylinder water-cooled LHR directinjection diesel engine. In this investigation, thecombustion, performance and emission analysiswere carried out in a diesel and biodiesel fueledconventional and LHR engine under identicaloperating conditions. The test result of biodieselfueled LHR engine was quite identical to that ofthe conventional diesel engine. The brakethermal efficiency (BTE) of LHR engine withbiodiesel is decreased marginally than LHRengine operated with diesel. Carbon monoxide(CO) and Hydrocarbon (HC) emission levels aredecreased but in contrast the Oxide of Nitrogen(NOX) emission level was increased due to thehigher peak temperature. The results of thiscomparative experimental investigation revealsthat, some of the drawbacks of biodiesel couldbe made as advantageous factors while using itas a fuel in the LHR diesel engine, and finallythe analysis was found to be quite satisfactory.Keywords : Biodiesel – Conventional Diesel,PSZ, LHR engine, Diesel engine.1. INTRODUCTIONFuel conservation and efficiency arealways the investigation points in the view ofengineers in developing energy system. The dieselengine generally offers better fuel economy thanpetrol engine. Even the diesel engine rejects abouttwo thirds of heat energy of the fuel, one third tothe coolant, and one third to the exhaust, leavingone third as useful power output. If the heatrejection could be reduced, then the thermalefficiency would be improved at least upto the limitset by the second law of thermodynamics. Lowheat rejection engines aim to do this by reducingthe heat energy from transferring to the enginecoolant. This energy could be recovered topromote a slight power to increase at the flywheel.This Low Heat Reduction (LHR) engine conceptprovide to be a viable means recovering thermalenergy normally radiated or exhausted from thediesel engine. A low heat rejection engine employssuitable insulation coating such as ceramics etc tothe cylinder and piston. LHR engine with 0.5mmthickness insulation coating for components givesbetter performance than with 1mm thickness. Thethermal efficiency with 0.5mm coating is higher byabout 6% to 8% under various operations. Due tothe insulation provided on the required surface ofthe cylinder, the amount of heat loss to the coolantis reduced and hence result in high combustionchamber temperatures. This leads to severeproblems such as high NOX emission levels andexhaust blow down losses.One of the viable significance of LHRengine is utilizing the low calorific value fuel suchas biodiesel. Studies have revealed that, the use ofbiodiesel under identical condition as that for thediesel fuel results in slightly lower performance andemission levels due to the mismatching of the fuelproperties mainly low calorific value and higherviscosity. The problems associated with the higherviscosity of biodiesel in a compression ignition (CI)engines are pumping loss, gum formation, injectornozzle coking, ring sticking and incompatibilitywith lubricating oil (8-12). The above identifiedproblems with the use of biodiesel in conventionaldiesel engine can be reduced in LHR enginesexcept for the injection problem. The presentinvestigation involves the comparison ofcombustion, performance and emission levels of
R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793788 | P a g ediesel and biodiesel (Jatropha based) inconventional and LHR DI diesel engines.2. FUEL PREPARATIONS ANDCHARACTERIZATIONThe vegetable oil was transesterfied usingmethanol in the presence of NaOH as a catalyst.The parameter involved in the above processingincludes the catalyst amount, molar ratio of alcoholto oil, reaction temperature and reaction time (13-15). The parameters for the biodiesel productionare optimized such as Catalyst amount, Molar ratio(Alcohol to Oil), Reaction temperature, andReaction time. The raw biodiesel obtained wasbrought down pH to a value of 7. This purebiodiesel was measured on weight basis and theimportant physical and chemical properties weredetermined as per the BIS standards (14).It isevident that, the dilution or blending of vegetableoil with other fuels like alcohol or diesel wouldbring the viscosity close to the specification rangefor a diesel. engine (16-17). The important physicaland chemical properties of the biodiesel thusprepared and given in table 1.TABLE 1 : Properties of the diesel andbiodiesel fuel3. DEVELOPMENT OF TEST ENGINEThe engine combustion chamber was coatedwith Partially Stabilized Zirconia (PSZ) of 0.5 mmthickness, which includes the piston crown, cylinderhead, valves and outside of the cylinder liner. Theequal amount of material has been removed from thevarious parts of the combustion chamber and PSZ wascoated uniformly. After PSZ coating, the engine wasallowed to run about 10 hours, then test wereconducted on it.4. EXPERIMENTAL PROCEDUREThe experimental setup and thespecification of the test engine are shown in Fig.land table 3 respectively.i. Test engine ii. Dynamometer:iii. Dynamometer controlleriv. Piezo electric pressure transducerv. Charge amplifiersvi. Data acquisition systemvii. Magnetic pickupviii. ComputerThe engine was coupled with an eddycurrent dynamometer for performance and emissiontesting. A piezoelectric transducer was mountedthrough an adopter in the cylinder head to measurethe in-cylinder pressure. Signal from the pressuretransducer was fed to charge amplifier. A magneticshaft encoder was used to measure the TDC andcrank angle position. The signals from the chargeamplifier and shaft encoder were given to theappropriate channels of a data acquisition system.The analyzer used to measure the engineexhaust emission was calibrated before each test.Using the appropriate calibration curve, themeasurement error for each analyzer was reducedas per the recommendation by the exhaust analyzermanual. The emission values obtained in the formof ppm and percentage was expressed in term ofspecific mass basis (g/kWh). The NOxmeasurements were corrected for humidityfollowing the procedure recommended by theSociety of Automotive Engineers (SAE, 1993).Exhaust gas temperature was measured using aniron-constantan thermocouple and mercurythermometer was used to measure the cooling watertemperature. Diesel and biodiesel was used in theconventional diesel engine and the PSZ coatedLHR engine. Cylinder pressure data was recordedand the other desired datas were processed.The experiments were carried out in asingle cylinder, naturally aspirated, constant speed,water-cooled direct injection diesel engine with thefollowing specificationsCharacteristics Diesel Fuel B100Density @15°C(kg/m3)837 880Viscosity @ 40°C(cSt) 3.2 4.6Flash point (°C) 65 170Cetane number 47 50Calorific Value(MJ/kg)42 39.5
R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793789 | P a g eTABLE 2 : Specification of test engine5. COMBUSTION AND HEAT RELEASEANALYSISThe combustion parameters can be studiedthrough the analysis of heat release rate obtainedfrom the pressure crank angle diagram. It isassumed that the mixture is homogeneous anduniform pressure and temperature at each instant oftime during the combustion process. The heatrelease rate can be calculated from the first law ofthermodynamics.i idU dQ dVm h pdt dt dt (1)Heat transfer ratedUdtWork done by the systemdVpdtBy neglecting the crevice volume and its effect, theequation (1) is reduced tof fdU dQ dVm h pdt dt dt (2)WhereMf - Fuel flow ratehf - Eathalpy of the fuelThis equation (2) can be further reduced todQn dQch dQht dV dTp mCvdt dt dt dt dt (3)WheredQndt- Net heat release ratedQchdt- Gross heat release ratedQhtdt- Heat transfer rate to the wallFrom the ideal gas relation PV=mRT this equation(3) is further modified in to11 1dQn n dV dPp Vdt n dt n dt (4)The pressure at any angle obtained from thepressure crank angle diagram makes it possible tofind out the heat release at any crank angle.6. RESULTS AND DISCUSSIONS6.1 Cylinder PressureIn a CI engine the cylinder pressure isdepends on fueled LHR engine and higher by about2.75 % and 8.33% than conventional engine fueledwith diesel and biodiesel . This reduction in thecylinder pressure may be due to lower calorificvalue and slower combustion rates associated withbiodiesel fueled LHR engine. However the cylinderpressure is relatively higher than the diesel enginefueled with diesel and biodiesel.It is noted that the maximum pressureobtained for LHR engine fueled with biodiesel wascloser with TDC around 2 degree crank angle thanLHR engine fueled with diesel The fuel-burningrate in the early stage of combustion is higher in thecase of biodiesel than the diesel fuel, which bringthe peak pressure more closer to TDC.6.2 Heat Release RateFigure 3 shows the variation of heatrelease rate with respect to crank angle. It is evidentfrom the graph that, diesel and biodiesel fuelexperiences the rapid premixed combustionfollowed by diffusion combustion. The premixedfuel burns rapidly and releases the maximumamount heat followed by the controlled heatrelease. The heat release rate during the premixedcombustion is responsible for the cylinder peakpressure.The maximum heat release of LHR enginewith biodiesel is lower about 8.1% than LHRengine fueled with diesel and higher about 2.4%and 7.02% respectively than conventional enginefueled with diesel and biodiesel. It was found that,premixed combustion in the case of biodiesel fuelstarts earlier than the diesel fuel and it may be dueto excess oxygen available along with higheroperating temperature in the fuel and theconsequent reduction in delay period than that ofdiesel fuel. It may be expected that highNo of stroke Four strokeNo of cylinder OneBore, mm 87.5Stroke, mm 110Compression ratio 17.5:1Rated power output 4.4 kW @1500rpmInjection Pressure, bar 200Injection timing 24° BTDC
R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793790 | P a g esurrounding temperature and oxygen availability offuel itself (bio diesel) reduce the delay period.However higher molecular weight lower calorificvalue and slightly higher value of viscosity bringdown the peak heat release during the premixedcombustion period. The heat release is welladvanced due to the shorter delay period and earlyburning of the biodiesel. It is found that, the heatrelease rate of biodiesel, normally accumulatedduring the delay period follows the similar trendslike diesel fuel.6.3 Cumulative Heat Release RateFigure 4 shows the variation of cumulativeheat release with respect to crank angle. In general,the availability of oxygen in the biodiesel fuel itselfenhances the combustion and thus increases the netheat release. In this investigation at full load, thenet heat release for LHR engine fueled withbiodiesel is lower by about 8.34% than LHR enginefueled with diesel and higher by about 2.35% and7.04% respectively than LHR engine with biodieseland conventional diesel engine fueled with dieseland biodiesel.6.4 Brake Thermal EfficiencyFigure 5 shows the variation of brakethermal efficiency with engine power output. Themaximum efficiency obtained in the case of LHRengine fueled with biodiesel at full load was lowerby about 2.92% than LHR engine fueled with dieseland higher by about 1.77% and 5.6% respectivelythan conventional diesel engine fueled with dieseland biodiesel. In overall, it is evident that, thethermal efficiency obtained in the case of LHRengine fueled with biodiesel is substantially goodenough within the power output range of the testengine.6.5 Specific Fuel ConsumptionThe variations of brake specific fuelconsumption (SFC) with engine power output fordifferent fuels are presented in figure 6. Atmaximum load the specific fuel consumption ofLHR engine fueled with biodiesel is higher byabout 6.27% than LHR engine fueled with dieseland lower by about 3.77% and 11.14% respectivelythan conventional engine fueled with diesel andbiodiesel.Fig. 6 Variation of Specific fuel consumptionwith engine power outputThis higher fuel consumption was due tothe combined effect of lower calorific value andhigh density of biodiesel. The test engine consumedadditional biodiesel fuel in order to retain the samepower output.
R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793791 | P a g e6.6 Specific Energy ConsumptionFigure 7 shows the variation betweenspecific energy consumption (SEC) and enginepower output. The heat input required to produceunit quantity of power is proportionately varyingwith SFC. Higher the energy required at low loadand decreases by increasing the load. It is foundthat the specific energy consumption of LHRengine with biodiesel is higher by about 1.27% thanthe LHR engine with diesel fuel and lower by about3.78% and 11.15% respectively for conventionaldiesel engine with diesel and biodiesel.6.7 Exhaust Gas TemperatureFigure 8 shows the variation of exhaustgas temperature with engine power output. At fullload, the exhaust gas temperature of LHR enginefueled with biodiesel gives lower value by about2.52% than LHR engine fueled with diesel andhigher by about 2.83% and 6.13% respectively thanconventional engine with diesel and biodiesel. Thehigher operating temperature of LHR engine isresponsible for the higher exhaust temperature. Theexhaust gas temperature of biodiesel varyingproportionately with engine power output as in thecase of diesel fuel. It may be due to the heat releaserate by the biodiesel during the expansion iscomparatively lower than diesel.6.8 Carbon MonoxideThe variation of carbon monoxide (CO)with engine power output is presented in figure 9.The fuels are producing higher amount of carbonmonoxide emission at low power outputs andgiving lower values at higher power conditions.Carbon monoxide emission decreases withincreasing power output. At full load, CO emissionfor LHR engine with biodiesel fuel is lower byabout 10.73%, 26.82% and 31.89% respectivelythan LHR engine with diesel, conventional enginefueled with biodiesel and diesel. With increasingbiodiesel percentage, CO emission level decreases.Biodiesel itself has about 11% oxygen content in itand it may helps for the complete combustion.Hence, CO emission level decreases withincreasing biodiesel percentage in the fuel.6.9 Unburned HydrocarbonThe variation of hydrocarbon (HC) with respect toengine power output for different fuels are shownin figure l0. The high operating temperature inLHR engine makes the combustion nearly completethan the limited operating temperature condition asin the case of diesel engine. At full loadhydrocarbon emission levels are decreases for LHRengine fueled with biodiesel than LHR enginefueled with diesel and diesel engine fueled withdiesel and biodiesel such as 9.8%, 17.21% and21.31% respectively. The air fuel mixture, whichwas accumulated in the crevice volume, wasreduced due to the high temperature andavailability of oxygen, which in turn leads toreduction in unburned hydrocarbon emissions.
R. Lokanatham, Prof. K. Ravindranath / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.787-793792 | P a g eFigure 11 shows the variation of oxides ofnitrogen with engine power output. The mainreason for the formation of oxides of nitrogen in an1C engines are high temperature and availability ofoxygen. At maximum load, NOx emission for LHRengine with biodiesel fuel is higher about 7.09%,13.35 and 20.37% respectively than LHR enginefueled with diesel and conventional diesel enginewith biodiesel and diesel. In LHR engine, theoperating conditions are in favor of NO species andsuch as the availability of oxygen in the fuel itselfother than the oxygen available in the air and hightemperature due to insulation coating, whichenhance the NO species formation.6.10 Particulate MatterFig. 12 shows the variation of particulatematter with engine power output. The particulatematter of LHR engine with biodiesel fuel is higherabout 3.1% than LHR engine with diesel andlower by about 3% and 11.1% respectively thanconventional diesel engine fueled with diesel andbiodiesel. It is clearly found that, the particulatematter for biodiesel was higher irrespective of theengine used compared with the diesel fuel. This isdue to the incomplete combustion of biodieselfuel.Fig. 12 Variation of particulate matter withsengine power output7. CONCLUSIONThe biodiesel produced from Jatropha oil bytransesterification process reduces the viscosity ofthe oil in order to match the suitability of dieselfuel. The diesel engine is modified in to LHRengine by means of partially stabilized zirconia(PSZ) coating. The various combustion parameterssuch as Cylinder pressure, rate of heat release,cumulative heat releases were analyzed.7.1 At full load condition, the cylinder pressure inthe case of biodiesel fueled LHR engine waslower than that of the diesel fueled LHRengine. Even though this reduction underidentical condition is substantial, the absolutevalue of this cylinder peak pressure is wellwithin operating limits of the test engine.7.2 The final analysis of the heat release showsthat, the value of net heat release in the case ofbiodiesel fueled LHR engine is substantiallygood enough forth effective work done of thetest engine. The performance characteristicssuch as brake thermal efficiency, specific fuelconsumption and specific energy consumptionand various emission characteristics werecompared.7.3 The maximum efficiency obtained in the caseof LHR engine fueled with biodiesel was lowerthan the LHR engine operated with diesel fuel.However the efficiency of the LHR enginewith biodiesel fuel is well within the expectedlimits.7.4 The exhaust gas temperature of LHR enginefueled with biodiesel was lower than LHRengine fueled with diesel throughout theoperating condition. The low exhaust gastemperature indicates the heat release rateduring the late combustion was comparativelylower than diesel fuel.7.5 The specific fuel consumption of LHR enginewith biodiesel was higher than LHR enginefueled with diesel. The higher consumption offuel due to low calorific value and highviscosity. Even though it could be expected tothe offset by the cost of biodiesel.7.6 The specific energy consumption of LHRengine with biodiesel was higher than LHRengine fueled with diesel fuel.7.7 It was found that, CO and HC emissions forLHR engine with biodiesel was considerablylower than LHR engine fueled with diesel.This reduction of emissions due to excessoxygen availability along with higheroperating temperature. NO emission for LHRengine with biodiesel fuel was higher thanLHR engine fueled with diesel. The operatingconditions of LHR engine were favorable toNO formation. The increase in emission levelwas within the acceptable limits.7.8 From the above points noted during theexperimental investigation it reveals thepossibility of using the bio-diesel in LHRDiesel Engine. The combustion, performanceand emission characteristics show thesuitability of biodiesel in LHR Engines.
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