Study On Closed-loop Control Of Gasoline Engine Cold Start Based On Spark Plug Ion

According to the United States Federal Test Procedure of FTP-75tested, nearly80%of HC, CO emissions were generated in the first minutes of cold starting in gasolineengine which with catalytic converters. However, with the increasingly stringentemissions regulations, warm-up time of40seconds after the engine starting wascanceled in Euro Ⅲ, Euro Ⅳ.So the research on emission control during cold startwas very important.First, the cold start process and emission characteristics was analysed in this paper,then it researched the relationship between cold start emissions and ignition advanceangle. Second, the relationship among the ion current, the cylinder pressure, and theignition advance angle was studied. Then put forward a closed-loop control strategywhich uses spark plug ion current as the feedback signal to control ignition advanceangle to reduce emissions. And the engine model, the ion current model and controlmodel were established for joint simulation using GT-power and Simulink softwareplatform.The simulation results showed that: through the control of ignition advance angle,make the cylinder pressure peak value appeared ATDC10°CA to21°CA, then thecombustion condition would be improved in the cylinder, and emission would bereduced. In1500r/min,1200r/min,1000r/min,900r/min,700r/min and500r/min sixkinds of speed, compared parameters before and after control. The result showed: thetorque before and after control were increased by9.03%,9.52%,13.6%,13.2%,18.5%and30.0%.The fuel consumption rate was decreased by3.0%,5.2%,3.5%,6.4%,8.5%and8.6%. In terms of emissions: HC was decreased before and after control by5.9%,11.1%,12.2%,8.2%,7.0%and15.7%. CO and NO also decreased, but the declineis not great.