48 V起动发电一体式电机提升发动机排温的试验研究

Study on Increasing Exhaust Temperature by Using 48 V Belt-Driven Starter Generator

基于48 V起动发电一体式电机(belt-driven starter generator,BSG)的起动机和发电机双重功能,在全球轻型车测试循环(world light-duty test cycle,WLTC)起始阶段,控制BSG电机行使发电功能,在飞轮端输出功率不变的条件下提升发动机总功率,从而快速提升排气温度;利用BSG电机的快速起动功能,在WLTC循环的怠速工况关闭发动机,避免出现低温排气流,从而起到后处理保温作用。结果显示,在WLTC循环过程中,涡轮后排温达到选择性催化还原系统起燃温度(预设为200℃)的时间由780 s缩短到650 s,尿素喷射起喷时刻提前了约130 s;同时在荷电状态略微下降的条件下,WLTC循环油耗降低2.4%。

Based on the starter and generator function of 48 V belt-driven starter generator(BSG),the generator function of BSG system was used to increasing engine exhaust temperature during world light-duty test cycle(WLTC).The engine exhaust temperature was increased by increasing the overall engine power while maintaining the same crankshaft output torque.By using the starter function,the engine could be shut off during idle period to keep after-treatment system warm.Finally,the time to reach the temperature of selective catalyst reduction lighting-off was shortened from 780 s to 650 s,and the timing of urea injection was 130 s ahead.Meanwhile,the overall fuel consumption of WLTC was reduced by 2.4%with a slight decrease of state of charge.