汽油/CNG两用燃料汽车燃料模式对比及标定优化

Analysis on Fuel Mode for Gasoline/CNG Dual-fuel Vehicle and Its Calibration Optimization

汽油/CNG两用燃料汽车与汽油车工作原理的差异使两用燃料车排放和车载诊断(OBD)系统的标定存在诸多难点。通过对汽油和压缩天然气(CNG)2种燃料燃烧时产生的功率、扭矩、排温以及振动的分析,发现CNG模式较汽油模式时的功率和扭矩偏小、排气温度偏低、发动机振动偏小。使用对比标定的方法,在汽油模式的基础上对燃气喷射脉宽进行修正,以优化排放;对排温及振动模型进行分析,以完成对氧传感器加热和失火等OBD系统的标定。该方法使两用燃料汽车的排放及OBD系统能够满足国家法规及用户的需求。

The differences of working principles between gasoline/CNG dual fuel vehicles and gasoline vehicles make lots of difficulties in the calibration of dual fuel vehicle emission and OBD system. Through analysis of power, torque, exhaust temperature and vibration while gasoline/CNG dual fuel vehicle burns in two kinds of fuel, it is found that compared with the fuel mode, the power torque in the gas mode is smaller, the exhaust temperature is lower and the engine vibration is smaller. So using contrast calibration methods modifies the gas injection pulse width on the basis of the fuel model to optimize the emission, and modifies the exhaust temperature and vibration models to match the oxygen sensor heat and misfire of OBD systems, which can make the emission and OBD meet China national standards and the demands of customers.