车用汽油机停缸时循环功耗研究

发动机停缸时，不同的停缸方案以及采用不同的控制参数所对应的循环功耗和摩擦功耗有较大差别，影响停缸后发动机性能。基于电磁驱动配气机构全柔性化的特点，研究了滞留废气、滞留空气、排气门常开3种停缸状态下的功耗。仿真结果表明，减少停缸循环缸内气体量有利于降低功耗，排气门常开方案功耗随气门升程增加而降低。最后确定了以最小功耗提高经济性和最大功耗改善换挡品质的停缸方案。

Study on Cycle's Energy Losses of Vehicle Gasoline Engines for CDA

Under conditions of CDA, the cycle's energy losses and friction losses had great differences under different valve strategies and control parameters. Based on EMVT, energy losses of three valve strategies including trapped exhaust gas, trapped fresh air and keeping exhaust valve open were analyzed. The simulation results show that reducing the trapped gas of deactivated cylinder helps to reduce energy losses, and the energy losses for the exhaust valve open strategy decreases with the increase of lift. Lastly, the CDA strategy with the minimum energy losses to improve the fuel economy and the CDA valve strategy with the maximum energy losses to improve the shift quality were achieved.