增程式发动机失火、爆燃造成飞轮断裂的研究

Study on Flywheel Crack due to the Misfire and Knocking of Engine in Range-Extender

某增程式电动样车在高速高功率增程模式下出现了飞轮断裂故障,针对增程器双质量飞轮所有断裂原因进行逐一排查,锁定主要可能原因为软件控制策略不完善导致飞轮所受冲击过大。对增程式样车在不同工况下的飞轮受力情况进行了测试,结果显示发动机失火、爆燃时的飞轮冲击转矩均超过了极限,分别导致了飞轮的变形和断裂。通过发动机和增程器两方面控制策略的优化,如修正发动机爆燃控制模型、设定发动机进气温度阈值、在增程器控制中添加降功率策略的第二重保护等,避免了发动机失火、爆燃的发生。优化控制策略后的增程式样车经过了转鼓试验台、实际试验场的高温环境试验及3×10~4 km实际道路耐久试验的验证,试验后拆解显示飞轮完好。

The flywheel of a range-extender electric vehicle cracked during operating under the mode of high speed and high power. Through checking all the reasons of crack for the double mass flywheel one by one, the main possible reasons were focused on defective control strategies which resulted in the excess shock on flywheel. By testing the stress of flywheel under different operating conditions for the range-extender vehicle, the result showed that the shock torque on flywheel exceeded the limit in the state of engine misfire and knocking. The two tests resulted in flywheel’s deformation and crack respectively.Optimizing the control strategies of engine and range-extender, for example, correcting the knocking control mode of engine, setting the intake temperature of engine, and adding the strategy to lower power in the control of range-extender as the dual protection, prevented the engine misfire and knocking from happening. The range-extender sample vehicle with the optimized control strategies has been verified by dynamometer test, proving ground in thermal environment and 30 000 km road durability test. After disassembly, it shows that the flywheel is in good condition.