气门控制策略对无节气门发动机性能的影响

Influence of valve control strategy to improve un⁃throttle engine performance

为了实现发动机高效清洁燃烧,利用自行开发的可变气门升程机构,在无节气门条件下研究了进气门调整策略(VIV)、排气门调整策略(VEV)和进排气门耦合调整策略(VICE)对发动机性能的影响。结果表明,与原发动机相比,3种气门控制策略都可以降低有效燃油消耗率(BSFC)并提高热效率(ITE);其中,VICE策略的效果最为突出,与原发动机相比BSFC和ITE最多可优化28%和6%;VIV策略和VICE策略都可以减小发动机泵气损失,尤其是VIV策略,与原发动机相比最多可以将泵气损失减少36%;3种策略都可以降低NO_x排放,其中VEV策略表现最优异;当NMEP超过0.3 MPa后,不同气门策略对THC排放的影响较小。

In order to achieve efficient and clean combustion,the influence of variable intake valve strategy(VIV),variable exhaust valve strategy(VEV)and variable intake valve combine exhaust valve strategy(VICE)on the un-throttle engine performance was studied based on a self-developed variable valve lift actuation.The results show that,compared with the original engine,the three valve control strategies all can effectively improve brake specific fuel consumption(BSFC)and indicated thermal efficiency(ITE).The VICE strategy showed the most optimal results,for example,BSFC and ITE were optimized by up to 28%and 6%compared to the original engine.Both VIV strategy and VICE strategy can reduce pumping loss,especially for VIV strategy,which can reduce pumping loss up to 36%compared with the original engine.All three strategies can reduce NO x emissions,among which VEV strategy performed best.Different valve strategies showed few effects on THC emissions when NMEP exceeded 0.3 MPa.