Strategies And Methods To Calibrate Engine Electronic Controlled System For Cold Development

With the applying of electronic products into the automobile, control function of engine is realized by EMS. EMS is composed of electronic control units, sensors and actutors. Besides electronic hardware there are software and data base in ECU. In accordance with engine mode from sensors, corresponding parameters are selected from data base through switching signal from ECU and software analyzing, and are switched into instructions sending to corresponding actuators. Parts of defining parameters in data base are purpose of calibration. Under strategies instructions, optimum results are conserved into ECU including benchbase calibration, steering charscteristic,emission and"three-high"that is high altitude, hot weather and cold weather. EMS of engine is related to temperature, altitude when EMS is determined.All kinds of testing among different enviorment are carried out. Logic base of calibration strategy includes: 58 tooth synchronous logic, MAP sensor determination, fuel system, ignition system, idling system, air conditioner control, canister control, fan control, mile-record and failure diagnosis.Calibration steps are as follows:System definition, engine base calibration, vehicle base calibration, the hot weather calibration, cold development calibration, hot state validation and high altitude validation.Cold development calibration are as follows:â‘ fuel calibration method during cool startâ‘¡Idling controlâ‘¢Ignition controlMain calibration parameters are:1 start A/F During cranking: parameters are CRANKREF, FPRFMVL, F37A, F37B, FTRIMCLT, FTPSAECLT and F37C.Air-fuel ratio during warm engine state : F51, F52 and K-FVEL-AF-TOVT-DECAY-MULT.Logic parameter of gasoline pump openning:FPRMTMR, KFPPU.2 Idling air compensation: FCRK KCRDCY Pbaro F90D F14MA.3 Spark advance angleCorrection parameter: F2E, FICH.In terms of practical results, preinjection pulse width FPRFMBL is what is good and bad result in what is long and short on the start time. Calibration parameter CRANREF determine quality on starting process. Althongh other references are inferior to the above references, it is optimum references, and keep running normaly during cool state.By applying calibrate strategy and method into practice (reality), test on the cold is satisfing. It has been proved that present strategy basely meet the requirement. Calibration method has been applied skillfully. Though the stratey methods are same, different people and practice result in different calibration results, then it directly influences developing result of engine performance.