LPG公交客车发动机舱结构与散热特性分析

Analysis on the Structure and Cooling Performance of LPG Bus Underhood

针对广州液化石油气公交客车在恶劣工况下行驶时发动机舱内温度和冷却水温过高的问题,采用计算流体动力学的方法,对发动机舱空气流场和温度场进行了数值求解,并分析了其与发动机舱内结构布局影响关系。其中,计算所需的舱内高温部件温度边界条件,通过采用红外热像仪对台架上的发动机进行了温度成像的方法获得。仿真计算发现:该发动机舱在中冷器、散热器后端区域存在部分空气流动受阻,热量累积形成高温区域等问题。为此,对散热器、中冷器及风扇的布置形式进行了改进设计,并进行了仿真验证。对比分析表明:结构改进后,发动机舱内的温度普遍降低,发动机舱散热不良,水温过高的现象得到了改善。

Aiming at the overheat of air inside the underhood and the excess of coolant water temperature of LPG（Liquefied Petroleum Gas）bus running in harsh conditions,the airflow and temperature field inside and outside the underhood were calculated based on the method of computational fluid dynamics,in order to analyze the effect of the underhood structure and layout on the air distribution and temperature field inside the underhood.And the temperature boundary condition of the hot parts were acquired by the infrared camera.Though the CFD simulation,high temperature regions inside the underhood,such as the region behind the cooling fan,were found.Accordingly,a new and improved structure and layout of the underhood is presented and proved to be effective in reducing the temperature inside the underhood by using the same simulation method.