The three dimensional temperature field of the gap between piston and cylinder was obtained by numerically solving energy equation. The boundary condition of the equation was given in the form of heat transfer coefficient, instead of solving the temperature field of solid parts. The temperature field was calculated both under high speed high pressure condition and low speed low pressure condition. The numerical result was compared to experimental result under low speed low pressure condition and showed good agreement. It was shown that the influence of heat transfer coefficient on film temperature was significant. The adiabatic condition was reasonable under low speed low pressure condition, but invalid under high speed high pressure condition. It was a good way to describe the influence of solid parts on temperature using heat transfer coefficient but avoiding solving the temperature field of solids parts.

液压机械无级变速装载机发动机转速与车速解耦,具有节油、高效的优点,为了解决其工况繁多、动力匹配问题,以某液压机械无级变速装载机为研究对象,基于液压机械状态参数开展了装载机负载估计理论分析和仿真,建立了负载估计模型,仿真结果表明该方法能准确估计液压机械段内负载,结果偏差在±4.69%以内。在负载估计方法基础上,建立液压机械无级变速装载机工况识别模型以及整车仿真模型,通过理论分析与仿真相结合的方法,得到液压机械无级变速装载机在线工况识别方法及对应速比控制策略。仿真结果表明,该方法能够准确识别装载机当前工况,满足实际工程要求,所提出的分工况速比控制策略与常规策略相比,单作业循环时间减少了2.43 s,作业效率提高了4.42%,总油耗降低了1.41%。研究为装备液压机械无级变速器的装载机及拖拉机等提高生产效率及燃油...