发动机冷却模块振动优化

针对某轿车搭载直列四缸(L4)发动机型在发动机怠速开空调且冷却风扇处于最高转速2 470 r/m时,方向盘(SW)振动剧烈的问题,对减振连接点和SW的振动进行了振动试验测量,识别出了影响该工况下SW振动的主要因素.运用数值仿真,分析了由冷却模块（CRFM)引起的振动,CRFM系统振动特性数值分析模型的搭建,借助于能量解耦理论和Newmark Beta算法,该模型可分析CRFM搭载不同减振块组合后的模态频率及其在车架振动和风扇振动激励下的响应.振动优化针对搭载不同刚度性能减振连接块的CRFM振动特性进行仿真分析,优化后的CRFM可避开外部激励主要频段，且振动响应较小.

Optimization of engine cooling module vibration

The steering wheel (SW) of an automobile with L4 engine vibrates greatly, when the engine is idling with air conditioner working and cooling fan rotating at its top speed 2 470 r/min. Series of experiments were taken to test the vibration of isolators’ connecting points and the SW so that the factors influencing SW vibration under specific working conditions could be identified. The vibration induced by the engine condenser-radiator-fan module (CRFM) was analyzed by numerical simulation. The numerical model of CRFM vibration was established with the help of energy decoupling and Newmark-Beta methodology, which could analyze the modal frequencies and vibration response of CRFM with different isolator groups under excitation of chassis and cooling fan vibration. The optimization investigates the stiffness of CRFM isolators so that CRFM can evade the external excitation frequency band and its vibration response can be reduced.