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基于废气-负荷控制策略的汽油机HCCI燃烧,利用排气门管理内部残余废气率,控制发动机负荷,进气门升程和相位调节缸内状态,控制着火和优化燃烧相位。本文利用KIVA对全可变气门机构单缸机进行CFD仿真,研究缸内温度、残余废气分布特征,以及温度、废气不均匀分布对着火的影响。结果表明,采用废气-负荷控制策略,改变进气门相位和升程可以调节缸内温度和残余废气的不均匀分布。随着内部残余废气率增大,进气门对缸内温度和废气率分布不均匀度的调控能力增强。大废气率条件下,温度和废气率不均匀度对着火时刻调节作用较明显,可以实现10°曲轴转角的有效调节;小废气率条件下,由于缸内温度和废气不均匀分布差别较小,其对于着火时刻的调节作用表现得不明显。
Based on the HCCI combustion of gasoline engine with exhaust-load control strategy, exhaust valve is used to manage the internal residual exhaust gas rate, control engine load, intake valve lift and phase adjust the cylinder status, control the ignition and optimize the combustion phase. In this paper, KIVA was used to simulate the CFD of all-variable valve train single-cylinder engine, and the influence of in-cylinder temperature and residual exhaust gas distribution, as well as the uneven distribution of temperature and exhaust gas on ignition were studied. The results show that the in-cylinder temperature and residual exhaust gas non-uniform distribution can be adjusted by changing the intake valve phase and lift using the exhaust-load control strategy. With the increase of internal residual gas rate, the control ability of intake valve to the in-cylinder temperature and the uneven distribution of exhaust gas rate is enhanced. Under the condition of large exhaust gas rate, the non-uniformity of temperature and exhaust gas rate plays a significant role in adjusting the ignition moment, which can effectively adjust the crank angle of 10 °. Because of the small difference in in-cylinder temperature and exhaust gas unevenness, Its regulation of the moment of ignition did not appear obvious.