POTENTIALS OF AIR-EGR DILUTION FOR IMPROVING
PERFORMANCE OF A HIGH COMPRESSION RATIO SPARK-IGNITION
ENGINE FUELED WITH METHANOL |
Kaichang Lai 1,2, Hong Chen 2, Jiakun Du 2, Wenfeng Zhan 2, Yuhuai Li 2, Fangxi Xie 1 |
1State Key Laboratory of Automotive Simulation and Control, Jilin University 2GAC Automotive Research & Development Center |
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ABSTRACT |
The effects of air and exhaust gas recirculation (EGR) dilution of a spark ignition engine fueled with methanol
under different loads were studied by experiment in this paper. Such as ignition delay, combustion center (CA50), IMEP,
break thermal efficiency (BTE) and other parameters were investigated to assess the combustion performance. And discussed
in depth the balance between NOx emissions and economic performance represented by brake specific fuel consumption
(BSFC). The results showed that combustion progress such as ignition delay, combustion duration and CA50 were more
sensitive on the changes of EGR, introducing EGR under the same dilution rate prolonged combustion process. Air-EGR
dilution showed the best improvement of IMEP and break thermal efficiency, except the optimal area, increasing EGR rate
will decreased IMEP and BTE. Air-EGR dilution strategy showed the best improvement on BSFC than air dilution than EGR
dilution. Under light load and high load, when the lowest BSFC was obtained, NOx emissions were less than 0.5 g/kWh with
air-EGR dilution strategy. |
Key Words:
Lean burn, Air and EGR dilution, NOx emissions, Break special fuel consumption, Methanol |
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