工况及配缸间隙对活塞敲击力影响规律

Analysis of the influence of operating conditions and piston-liner clearance on piston slap force

针对发动机的运行工况及配缸间隙对活塞敲击力的影响规律展开研究。采用EXCITE软件搭建了活塞运动仿真模型与发动机多体动力学仿真模型。基于验证后的模型研究了活塞二次运动及活塞敲击力的特点,分析了转速及转矩等运行工况及配缸间隙的影响规律。研究结果表明:在压缩上止点附近活塞的二次运动最为明显,主推力面上存在最大活塞敲击力;随着转速的增加,活塞惯性力增大,使活塞敲击力增大;随转矩的增加,活塞所受侧向力增大,使得活塞敲击能量增加;随着配缸间隙的增加,活塞二次运动加剧,活塞敲击力相应增加。

To investigate the influence of operating conditions of an engine and piston-liner clearance on piston slap force,this paper builds a piston motion simulation model and an engine multi-body dynamics simulation model based on the EXCITE software.The characteristics of the piston secondary motion and the piston slap force are studied through the verified models.The models are also used to analyze the effects of operating conditions like engine speed and torque as well as piston-liner clearance.The results show that the piston secondary motion is most obvious near the top dead center of the compression stroke and the maximum value of piston slap force appears at the main thrust side.With the increase of the rotational speed,the piston inertial force increases,which makes the piston slap force increase.With the increase of the torque,the lateral force of the piston increases,which strengthens the piston slap force.The piston secondary motion intensifies with the increase of the piston-liner clearance and this contributes to the increase of the piston slap force.