涡轮增压汽油机废气旁通阀瞬态控制研究

在不同瞬态工况下使用不同的废气旁通阀PID目标控制策略,建立涡轮增压汽油机瞬态计算模型.对发动机定转矩加减速工况下的瞬态响应进行模拟计算,并与原机响应特性做对比分析.结果表明,在定转矩加速工况下,以适当增大的各固定转速下增压压力作为瞬态控制目标值,可以显著改善发动机的瞬态响应.在发动机定转矩减速工况下,采用前期适当延长废气旁通阀全开的时间,待转速下降到1.25倍目标转速后,控制目标切换到增压压力的控制策略能够缩短发动机的响应时间.与此同时,采用废气旁通阀瞬态控制方法,不仅能够提升涡轮增压汽油机瞬态响应性能,而且可以防止瞬态工况下增压器超速和喘振.

Research on Transient Control for Waste-gate of Turbocharged Gasoline Engine

The different PID control strategies of waste-gate were used under different transient conditions to establish the transient calculation model of turbocharged gasoline engine. The transient response under constant torque acceleration and deceleration conditions was simulated and compared with the transient response of original engine. The results show that the transient response is improved remarkably when the transient control target value takes the greater boost pressure at each fixed speed. In constant torque deceleration condition, transient response time is shorten when using the strategy that makes the waste-gate fully open in early stage until the speed reaches 1.25 times of the target speed, and then switches the control target to the boost pressure. At the same time, this way not only improves the transient response performance of the engine, but also prevents the turbocharger from surging and overspeeding under transient conditions.