谭丕强,周捷,楼狄明,等.废气再循环率对高压缩比增压直喷汽油机燃烧与排放特性的影响[J].内燃机工程,2022,43(3):100-108.
废气再循环率对高压缩比增压直喷汽油机燃烧与排放特性的影响
Effects of Exhaust Gas Recirculation Rates on Combustion and Emission Characteristics of High Compression Ratio Turbocharged Direct Injection Gasoline Engine
DOI：10.13949/j.cnki.nrjgc.2022.03.014
关键词:增压直喷汽油机  高压缩比  废气再循环  燃烧  排放
Key Words:supercharged direct injection gasoline engine  high compression ratio  exhaust gas recirculation（EGR）  combustion  emission
基金项目:国家重点研发计划项目（2018YFB0105802）
作者单位E-mail
谭丕强* 同济大学 汽车学院，上海 201804 tpq2000@163.com 
周捷 同济大学 汽车学院，上海 201804  
楼狄明 同济大学 汽车学院，上海 201804  
胡志远 同济大学 汽车学院，上海 201804  
房亮 同济大学 汽车学院，上海 201804  
赵彬皓 同济大学 汽车学院，上海 201804  
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摘要:以一台采用废气再循环（exhaust gas recirculation， EGR）技术的增压直喷汽油机为研究样机，试验研究了高压缩比15.0时不同EGR率（0%、5%、10%、15%）下该机的燃烧和排放特性。研究结果表明，与常规的压缩比11.5相比，采用高压缩比15.0时，该机缸内最高燃烧压力升高，点火正时提前，燃烧持续期延长，平均指示压力变动系数增大，有效热效率显著提高；碳氢化合物（hydrocarbon， HC）排放和颗粒物数量增加，CO排放和颗粒物质量降低， NOx排放略有升高。采用EGR技术能够有效抑制爆震和降低NOx排放。相同工况下，随着EGR率升高，该机的燃烧持续期延长，平均指示压力变动系数增大，低负荷（制动平均有效压力（brake mean effective pressure， BMEP）为0.5 MPa）下的缸内最高燃烧压力逐渐下降，有效热效率变化不大。高负荷（BMEP为1.0 MPa）下的缸内最高燃烧压力先上升后下降，有效热效率整体呈上升趋势，高压缩比情况下该机EGR率为10%时的热效率最高，为38.45%；CO排放先减小后增加，HC排放逐渐增加，NOx排放降幅增大，最大降幅达86.8%。
Abstract:A turbocharged direct injection GDI gasoline engine with exhaust gas recirculation（EGR） technology was used to study the combustion and emission characteristics of the engine under different EGR rates （0%， 5%， 10%， 15%） at a high compression ratio of 15.0. The research results showed that compared with the conventional compression ratio of 11.5， when the machine adopted a high compression ratio of 15.0， in terms of combustion characteristics， the ignition timing was advanced and the combustion duration was prolonged， which led to the maximum explosion pressure in the cylinder， the average indicated pressure variation coefficient and the effective thermal efficiency were significantly improved. In terms of emissions， hydrocarbons（HC） and particulate numbers increased， but CO and particulate matter mass decreased， and nitrogen oxides（NOx） emissions increased slightly. EGR technology could effectively suppress knocking and reduce NOx emissions. Under the same working conditions， with the increase of EGR rate， the combustion duration of the machine and the coefficient of variation of the average indicated pressure increased， and under low load conditions （brake mean effective pressure was 0.5 MPa）， the maximum burst pressure in the cylinder gradually decreased， and the effective thermal efficiency did not change much. But under high load conditions （brake mean effective pressure was 1.0 MPa）， the maximum burst pressure in the cylinder showed an increase and decrease behavior， and the effective thermal efficiency showed an overall upward trend. In the case of high compression ratio， When the EGR rate of the engine is 10%， the thermal efficiency was the highest， which was 38.45%. Meanwhile， the CO first decreases and then increased， the HC gradually increased， and the NOx emissions significantly reduced， and the maximum reduction was 86.8%.
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