发动机排气口快速取样及示踪HC喷射的研究

Time Resolved Sampling and Tracer Injection Studies Related to Exhaust Port Hydrocarbon Oxidation

采用快速取样阀在一台单缸发动机排气口进行ＨＣ取样，对排气口ＨＣ取样浓度曲线进行分析，并采用向排气口喷射ＨＣ示踪气体来研究滞留在排气口附近的ＨＣ的氧化情况及其影响因素。试验表明：在排气开始阶段，ＨＣ浓度高峰是由于上一循环排出并停留在排气口附近、ＨＣ浓度较高的气体倒流产生的。此外。

Exhaust port time resolved sampling study was conducted in a single cylinder engine using a fast active sampling valve.Time resolved data were analysed and then a tracer injection study was performed to investigate the hydrocarbon oxidation in the exhaust port.Results show that the peak of HC concentration at the beginning of an exhaust stroke is because of the backflow of the exhausts,produced from the last cycle,having stayed at the exhaust port and with a dense HC compotent of them.Furthermore,the port temperature plays a significant role on HC oxidation.