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对492WQB汽油机的每个试验工况从各缸排气道出口中心附近进行了连续10s共90次的采样, 对采样气体中NOx、HC及CO的浓度分别采用了化学发光法、氢火焰离子法及不分光红外法进行了分 析,并把连续采样气体的排放平均值作为每个测试工况的排放值。试验结果表明,各缸空燃比等的微小 差异,引起的各缸NOx、HC及CO排放的最高值与最低值比可达10倍、5倍及6倍;缸间排放差异随着 点火时间、转速、节气门开度、混合气浓度的变化而变化;引起缸间排放差异的原因除空燃比的差异外还 有进气量等的差异。
The 492WQB gasoline engine for each test conditions from the exhaust outlet near the center of each cylinder for a total of 90 consecutive 10s sampling of the sample gas NOx, HC and CO concentrations were used chemiluminescence, hydrogen flame ionization And infrared spectroscopy were not analyzed, and the average continuous sampling of gas emissions as the emission value of each test conditions. The experimental results show that the slight difference of air-fuel ratio of each cylinder can cause the highest and lowest values of NOx, HC and CO emissions of each cylinder up to 10 times, 5 times and 6 times. The difference between the cylinders varies with ignition time, Speed, throttle opening, changes in the concentration of mixed gas changes; causes differences between the discharge of the cylinder in addition to differences in air-fuel ratio there are differences in intake air and so on.