湍流射流点火甲醇发动机负荷拓展和性能优化研究

Investigation on the Load Expansion and Performance Optimizing of the Methanol Engine by Turbulent Jet Ignition

基于一台湍流射流点火(turbulent jet ignition,TJI)甲醇发动机开展发动机负荷拓展和性能优化试验研究。结果表明,稀燃工况下(过量空气系数大于1.4),采用进气增压技术可有效提升TJI甲醇发动机在高负荷工况下的燃烧稳定性和动力性,同时降低指示油耗率,提升排放性能;此外,基于进气增压技术提出了TJI甲醇发动机宽负荷工况下的最佳油耗运行策略。低负荷运行工况下,相较于质调节方式,采用量调节方式改变发动机负荷可使指示油耗率最高降低5.2%(平均指示压力为0.30 MPa时),一氧化碳(carbon monoxide,CO)、甲醛(methanal,HCHO)及碳氢化合物(hydrocarbon,HC)等污染物排放均有所降低,同时可提升燃烧稳定性,避免过于稀薄而造成的燃烧恶化现象。

The experimental investigation on the load expansion and performance optimizing of a turbulent jet ignition(TJI)methanol engine were carried out in this work.The results show that,under lean conditions i.e.when excess air coefficient is greater than 1.4,the combustion stability and power performance of the methanol engine with TJI system under high-engine load conditions were improved by adopting intake boost technology.And the fuel economy and emission performance of TJI methanol engine were optimized.Meanwhile,the strategies to achieve best fuel consumption rate of a TJI methanol engine under a wide range of engine load were proposed.Under light-load operating conditions,compared to the quality adjustment strategy,a 5.2%reduction of fuel consumption rate were obtained at the indicated mean effective pressure(IMEP)of 0.30 MPa by using the quantity adjustment strategy,and the emissions in terms of CO,HCHO and HC were reduced.Moreover,the usage of quantity adjustment strategy can avoid the deterioration of combustion caused by the over-lean mixture and improve the combustion stability of the TJI methanol engine.