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Diluted and Stoichiometric Combustion of Dual Fuel



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Lean Combustion 2004 Tomar Diluted and Stoichiometric Combustion of Dual Fuel Methane and Gas Oil Engine with HCCI Concept Okayama University Japan Eiji Tomita Nobuyuki Kawahara Background Increasing thermal efficiency reducing CO2 Reducing pollutant emissions HCCI low NOx no smoke Lean Slow speed low temperature combustion EGR Diluted stoichiometric Three way catalyst Time Homogeneous charge spark ignition Stratified charge spark ignition Flame propagation Dual fuel normal injection Dual Fuel Early injection PREDIC PCCI SCCI HCCI Auto ignition Experimental method Dual fuel engine methane diesel fuel high octane number high cetane number using a DI diesel engine Early injection 40 50 BTDC HCCI concept low NOx no smoke but rapid combustion with high NOx in high load EGR N2 dilution achieving mild combustion in high load Stoichiometric combustion ROHR and Exhaust emissions Single cylinder 4 stroke cycle Direct injection diesel fuel induction from intake port methane n 1000rpm inj TDC 50 BTDC Pilot injection t 0 4 1 1 0 37 5 Bore x stroke 92 x 96 mm Displacement 638 cm3 Compression ratio 17 7 1 Injector 4 holes 0 26mm Spray angle 150 Combustion chamber Deep dish Engine specifications and combustion chamber Flow meter Flow meter Light oil Injection pump Injection Pump Injection pump N2 gas Heater HeaterSurge Surge Heater tank tank Vaporizer Surge tank Vaporizer Methane gas Gas fuel Methane Gas Thermo meter Timing Timingbelt belt Flow meter Timing belt Surge Surge tank tank meter Flowmeter Flow Data recorder Mixer Water Oil Mix air Intake Flow meter Exhaust Intake Gap sensor Pressure Crank angle TDC Mixer Mixer Air Gas fuel Air Data Data recorder recorder Dynamometer Dynamometer N2 gas LightLight oil oil Thermo meter Thermo meter Experimental apparatus and method NOx NO meter X NOx meter HC HC meter HC meter Smoke meter Smoke meter Smoke meter Exhaust Exhaust Exhaust gas Normal injection timing Early injection timing Low temperature reaction due to diesel fuel One peak with retard combustion Pressure and ROHR without EGR Early injection Normal injection t 0 5 Smoke 0 Early injection Low NOx low HC Low CO Low cycle to cycle fluctuation High thermal efficiency Exhaust emissions and thermal efficiency w o EGR Increase in load increase and advance in Pmax and dQ d max decrease in effective work inj 50 BTDC mgo 4 mg cycle 0 Pressure and ROHR with increasing load w o EGR Smoke 0 In t 0 5 combustion is incomplete and bad In t 0 5 NOx increases while HC and CO are lower and combustion becomes stable Exhaust emissions and thermal efficiency w o EGR 100 10 0 dQ d J deg P MPa n 1000rpm mgo 4mg cycle 8 inj 50 BTDC t 0 6 6 9 1 4 2 n 1000rpm 80 mgo 4mg cycle inj 50 BTDC t 0 6 60 0 9 1 40 16 7 20 16 7 0 0 60 0 ATDC 60 60 EGR ratio 0 9 1 16 7 Pressure and ROHR 0 ATDC 60 9 1 16 7 23 1 25 9 28 6 33 3 Methane HC ppmC1 NOx ppm 5000 4000 3000 2000 1000 0 Decrease nozzle 150 n 1000 rpm inj 40 Oil 4mg cycl 16 7 23 1 25 9 28 6 33 3 nozzle 150 n 1000 rpm inj 40 Oil 4mg cycle 20 15 10 5 0 40 i 5000 Increase 0 0 2 0 15 10 5 33 Almost zero level 0 0 4 0 5 0 6 0 7 t 0 8 0 9 0 5 0 6 0 7 t 0 8 0 9 1 0 EGR ratio was changed according to equivalence ratio 0 1 20 20 0 0 4 Increase 0 3 30 10 0 4 CO 9 1 Methane 10000 Smoke 0 CV Pi 0 1 inj 40 BTDC early injection Exhaust emissions thermal efficiency and CV Pi with EGR inj BTDC 10 mgo 4mg cycle 4 Methane 20 4 40 4 50 4 40 8 Smoke could be seen due to fuel rich region in normal injection 40 0 Smoke 0 30 0 0 3 0 5 0 0 0 6 In early injection smoke level is almost zero and operating range becomes narrow 10 0 20 9 Smoke 10 n 1000 rpm t 1 0 13 0 60 50 40 30 20 inj BTDC 10 When diesel fuel increases the operating range in t 1 0 0 becomes wider Operating range of stoichiometric conditions When the injection timing of diesel fuel is advanced the range of equivalence ratio for the engine operation becomes narrow However the engine can operate even in stoichiometric mixture owing to EGR Under the condition of stoichiometric mixture smoke can be seen when the injection timing is 20 BTDC though smoke is not seen when the injection timing is 40 and 50 BTDC This is because there is no rich region of fuel due to the diffusion of the diesel fuel in the early injection Conclusions


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