基于AVL-BOOST的可变正时汽油机进气性能研究

Study on the intake performance of variable timing gasoline engine based on AVL-BOOST

基于AVL-BOOST建立EQ486汽油机的仿真模型.传统汽油机通过改变节流阀参数调整不同的节气门开度以满足不同负荷要求.可变正时汽油机节流阀无节流作用,将实测的气门升程数据按照不同的负荷要求输入仿真模型,选择不同的升程数据来满足不同的进气量以模拟负荷的变化.首先在同一转速下要求两种负荷调节模式下的进气量相同,这样才能保证缸内压力计算及进气仿真的精确性.可变正时汽油机通过改变进气门早关角来控制进气量,对不同进气早关角下的缸内压力变化进行分析,计算结果表明选择不同的气门运动规律控制进气量完全可以取代传统汽油机的节气门来调节负荷.其次保持同一转速设定不同的充量系数值,对两种负荷控制方式下的泵气损失的变化趋势进行了分析,结果表明可变正时汽油机在取消节气门后,进气过程中的节流作用大幅减弱,有效降低了吸气过程中的泵气损失,并且改善趋势随着充量系数减小更加明显.

Using AVL-BOOST to establish the simulation model of EQ486 gasoline engine, change the value of the throttle valve to meet the requirements of different load for the traditional gasoline engine.Variable timing engine throttle valve without inlet throttling effect,according to different load requirements,measured valve lift data was entered into the model,different lift data was selected to simulate the load changes.At the same speed,the requirements of the two modes of the same air intake,so as to ensure the accuracy of the calculation.Variable timing engine by changing the intake valve early angle to adjust the intake flow.The change of cylinder pressure under different EIVC angles was analyzed,the results showed that the choice of different valve motion data could completely replace the traditional throttle to adjust the air intake.Maintain the engine speed constant and set different filling coefficient,the two kinds of load control mode of the change trend of pumping loss was analyzed,the results showed that the throttle effect of the throttle valve was greatly reduced when the throttle valve was cancelled,and the pumping loss was decreased effectively,and with the decrease of the filling coefficient,the improvement trend was more obvious.