车用柴油机冷却系统的优化设计

Optimization Design of Cooling System for Vehicle Engine

在柴油机设计开发过程中,考虑到热负荷高、各缸孔间冷却均匀性差、缸盖鼻梁区出现热裂等现象的出现,本文对整机冷却水流速与换热进行模拟分析。通过模拟计算分析,得出冷却水在缸体进气侧从第一缸向第四缸流动过程中,流速与换热系数明显下降,这将会引起柴油机热负荷高、冷却均匀性差;喷油器和气门周边区域换热系数低,这将会是缸盖鼻梁区热裂的主要成因。针对上述设计开发过程中首先要考虑的潜在影响因素,本文提出了缸体水套设计优化方案、缸盖垫片优化设计方案;通过模拟计算的手段,得出本文提出的冷却系统优化设计方案,通过该方案的实施,有效降低产品设计完成后热负荷高、冷却均匀性差以及缸盖鼻梁区热裂等潜在失效风险。

During the design of diesel engine, considering of high heat load, bad cooling evenness of each cylinder hole, and cylinder head nose being cracked. This paper gives a model analysis for cooling water and heat changing. By model calculation analysis, when cooling water flows into the forth cylinder from the first cylinder, water speed and heat changing coefficient decreases, which would bring into high heat load, bad cooling evenness, and low heat changing coefficient of injector and valve areas, which is the most important reason of cylinder head nose cracking. The paper put forward optimization design plan of cylinder water jacket and cylinder head gasket, by model calculation, we got optimization design plan of cooling system., by which reduce heat load, bad cooling evenness, and cylinder head nose areas cracking.