摘要
基于一台1.5L的进气道喷射增压(PFI)汽油机,在保持原机匹配好的VVT角度、喷油压力和喷油相位不变情况下,采用低压废气再循环(LP_EGR)。通过优化发动机参数得到:发动机在EGR区域能起到较明显的节油效果。在中低转速的中大负荷区域节油7%~20%不等;发动机的抗爆震性明显改善,点火角最多可提前13.75度曲轴转角(CA);大部分中低负荷工况的NOx排放减少约20%~60%,最大降幅约为100%。但约占工况18.4%的大负荷工况排放恶化,负荷越大恶化越严重;HC排放有明显的改善。大部分工况的HC排放减少约15%~75%,最大降幅约为86%。综上所述,LP_EGR可使该发动机的油耗、抗爆震性和HC排放有明显的改善。而NOx排放在中低负荷工况改善较多,但大负荷工况恶化。
The low pressure exhaust gas recirculation(LP_EGR) was applied to a 1.5 L Turbocharged gasoline engine with Port Fuel Injection in the acticle, while maintaining VVT angles、the injection pressure and the injetion phase of the original enginge. The improvement of the Fuel-saving、the knocking performance and the NOx and HC emission of the engine are obtained with the engine parameters being optimized as follows: The engine fuel consumption rate significantly decreased in the region of the EGR, Especially there were 7% to 20% of different drops of the fuel consumption rate in the medium to heavy load area of the low and middle speed; The engine's Antiknock performance was improved remarkable with the ignition angle being advanced maximum 13.75 degree of the crankshaft's angle. Most of the engine's low and medium loads conditions of NOx Emissions' drop were different 20%to 60% with the biggest drop of about 100%.But the NOx Emissions of the engine's heavy load conditions which are about 18.4% in the whole engine's conditions are deteriorating as well as the more serious the deterioration of the greater the load; The Engine's HC emissions are reduced significantly. Most of the engine's working conditions of HC emissions were cut down about 15% ~ 75% with the biggest drop of about 86%. To sum up, The LP_EGR can make obvious improvement of the engine's fuel consumption rate、Antiknock performance and HC emissions. As for the engine's NOx emissions, they are more better in the low and medium load conditions and worser in the heavy-load conditions.
引文
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