镶圈内冷一体活塞的数值研究

为了研究镶圈和内冷油腔对活塞可靠性的影响,对同一型号、不同结构的带镶圈活塞进行模拟计算分析。首先对标定工况下的镶圈活塞进行硬度塞测温试验,作为温度场模拟计算的约束条件;然后考虑温度、燃烧压力、惯性力等因素影响进行热机耦合计算,得到活塞关键位置的变形、应力等结果;最后,使用疲劳分析软件计算活塞的高周疲劳。通过对比发现,镶圈内冷一体活塞一环槽根部温度分别比镶圈活塞和镶圈内冷活塞低6.5%,16%,其热应力分别降低了33%,15%,机械应力分别降低了31%,11%。结果表明,镶圈内冷一体结构的应用,有效避免了应力集中现象,既可以有效降低活塞头部热负荷和机械负荷,同时也能增强环槽的耐磨性,延长环槽下侧面的寿命。

Numerical Study on Piston with Oil Cooling Gallery in Ring Carrier

In order to research the influences of ring carrier and oil cooling gallery on the piston reliability,the simulations of piston with the ring carrier of same type and different structures were conducted.The temperature of piston with ring carrier was first measured by hardness plug test at rated condition,which was taken as the boundary conditions of simulation.Then thermal and mechanical coupling calculations were carried out by considering the influences of temperature,in-cylinder pressure and combustion force,and then the deformation and stress distribution of the key position of piston were acquired.Finally,the high cycle fatigue of piston was calculated by using fatigue analysis software.Compared with the piston with ring carrier and piston with oil cooling gallery in ring carrier respectively,the temperature at the root of first ring groove for the piston with oil cooling gallery in ring carrier decreased by 6.5% and 16%,its thermal stress decreased by 33% and 15% and its mechanical stress decreased by 31% and 11%.The results show that the structure of oil cooling gallery in ring carrier can effectively reduce the stress caused by thermal load and mechanical load and hence avoid the phenomenon of stress concentration.In addition,the new piston can enhance the wear resistance of ring groove and hence the service life for the lower side of ring groove prolongs.