并联混动用内燃机活塞外圆型线优化

车辆节能减排日趋严格,混合动力集合了内燃机和电动的优势,将成为未来一段时间的车辆主要动力。并联混合动力用内燃机在电池电量低时,必须立即启动并进入工作状态,增加了内燃机的拉缸风险,特别是外部环境温度较低时。为应对此问题,某并联混动汽油机设计了更为严苛的拉缸试验,但两次试验均失败。根据严苛拉缸试验、常规拉缸试验和800小时耐久试验裙部磨损结果对比分析,优化了裙部型线。活塞疲劳仿真分析证明新型线的疲劳安全因子依然在可接受范围内。活塞二阶运动仿真分析结果显示新型线不仅使干摩擦功峰值降低超过了50%,还在一个循环范围内产生干摩擦的曲轴转角区间也降低超过70%;而且新型线的油膜润滑摩擦功消耗在整个循环范围内也显著低于原型线,最大降低幅度超过50%。新型线活塞顺利通过了针对混动机型的严苛拉缸试验和其他发动机试验,确保了开发的顺利推进。

Piston Profile Optimization of Parallel Hybrid Engine

Vehicle energy conservation and emission reduction are becoming stricter and stricter. Hybrid power combines the advantages of internal combustion engine and electric power, and will become the main vehicles’ power in the future. When the battery is low, the parallel hybrid internal combustion engine must be started immediately and start to power the vehicle, which increases piston scuffing risk, especially when the weather temperature is low. To avoid the risk, one developing parallel hybrid gasoline engine was designed with a more stringent scuff test, but two tests failed. The skirt profile was optimized based on the skirt wear of the stringent and conventional scuff test and 800 hour endurance test. Piston fatigue simulation analysis proves that the fatigue safety factor of the new line is still within the acceptable range. The piston secondary motion simulation analysis shows that the new profile not only reduces the peak value of dry friction work by more than 50%, but also reduces the crank angle range of dry friction in a cycle by more than 70%; and the oil film lubrication friction of the new profile is also significantly lower than the old profile in the entire cycle, maximum reduction of more than50%. The new profile piston successfully passed the stringent scuff test and other engine tests, ensuring the smooth development of the development.