通用小型汽油机气缸布置方式对整机振动的影响

摘要

For 168F small gasoline engine ,the engine vibrations with non-shaft balance and crankshaft counterbalance were re-searched by the experiment and simulation .The results show that the main factor of gasoline engine vibration in idle speed is in-cylinder combustion cycle-to-cycle variation .In high speed ,the vibration refers to engine balance and cylinder layout .For the same structure of engine ,the equivalent vibration intensity is larger in higher speed .With ADAMS software ,small gasoline engine vibration under different cylinder angles is simulated .Compared with the horizontal and vertical layout of cylinder ,the engine vibration of 45° angle cylinder layout is smallest in high speed .Compared with the horizontal cylinder layout ,the equiva-lent vibration intensity of 45° angle cylinder layout decreases by 41 .9% .Compared with 25° angle cylinder layout ,the equiva-lent vibration intensity decreases by 29 .5% .For the different angles of cylinder ,the exciting force in each direction is differ-ent .At 45° angle of cylinder ,the distribution of exciting force is optimal and the gasoline engine vibration is smallest .%以168 F小型汽油机为例，用试验和模拟计算的方法研究了无平衡轴、用曲轴平衡块平衡往复惯性力的通用小型汽油机的振动特性。结果表明：低怠速时汽油机的振动主要受缸内燃烧循环波动的影响；高速时与整机平衡性和气缸布置等结构设计有关，转速愈高，整机当量振动烈度愈大。用 Adams软件模拟计算气缸斜置角不同时小型汽油机的振动特性，结果表明：气缸斜置45°时高速工况振动最小；卧式或立式气缸布置时高速工况振动都较大；气缸45°斜置结构较气缸卧式布置，整机当量振动烈度低41．9％，气缸斜置45°较原机25°斜置结构的整机当量振动烈度也可减少29．5％。气缸斜置角度不同，汽油机激振力在各个方向分力也不同，气缸斜置45°时激振力分布最合理，汽油机振动最小。