天然气发动机掺氢20%时瞬态排放性能研究

Research on Transient Emission Characteristics of 20% Hydrogen Enriched CNG Engine

对天然气发动机掺氢20%(体积比)的瞬态性能进行了研究。主要研究包括不同催化器ETC循环排放的对比、不同加速加浓因子的排放对比以及20%天然气掺氢发动机(HCNG)与纯天然气发动机的排放对比。试验结果表明:三种催化器都能使天然气掺氢发动机排放达到环境友好型汽车标准。随着加速加浓因子的增大,发动机扭矩跟随性越好,但会造成各种排放同时上升,特别是NOx上升幅度很大。三种氧化型催化转化器转化效率大小排序为:ECOCATⅡ型>国产催化器>ECOCATⅠ型。对于这三种催化器来说,随着催化效率的提高,排气阻力加大,发动机动力性下降,燃料消耗率上升。掺入20%氢气后,在不带催化器的情况下,NOx、CO、NMHC、CH4排放和燃料消耗率相对于原天然气发动机分别下降51%、36%6、0%4、7%和7%。

Transient emission characteristics of the hydrogen enriched compressed natural gas（HCNG） engine were studied,mainly including a series of comparisons of ETC cycle emissions of the engine in conditions of equipping with three types of catalytic converters,operating under various acceleration enrichment rates and adapting 20% hydrogen enrichment ratio（by volume） and not.The results show that all the three types of catalytic converters can make the HCNG engine meet enhanced environmentally friendly vehicle（EEV） emission standard.With the acceleration enrichment rate increasing,engine torque responsibility gets better,but all kinds of emissions rise,especially NOx emissions the most significantly.The order of conversion efficiency of the three converters is： ECOCAT type IIdomestic typeECOCAT type I.For the three converters,with the catalytic efficiency increasing the exhaust resistance adds,engine power reduces and BSFC worsens.Added 20% hydrogen in the CNG engine,NOx,CO,NMHC,CH4 emissions and BSFC of the HCNG engine without catalytic converter lower respectively 51%,36%,60%,47% and 7% compared to the original.