考虑柱塞两种姿态的柱塞副燃油泄漏研究

Fuel Leakage of Plunger Pair under Two Postures

高压共轨喷油器运行时柱塞的姿态会有偏心和倾斜状态,为了更加全面地研究柱塞副的泄漏情况,建立了考虑柱塞姿态的柱塞副间隙流动数学模型,包括雷诺方程、油膜厚度方程、油膜截面速度方程、非等温流动方程、稳态导热方程和燃油物性参数方程,并对这些方程进行了基于有限差分法的数值分析。利用该数学模型计算了燃油泄漏速率,并与经典公式计算的燃油泄漏速率以及试验值进行对比,验证了该研究模型的有效性。经分析得出了柱塞在柱塞套内倾斜状态下和偏心状态下,间隙燃油的泄漏速率、油膜厚度、温度、密度、黏度和比热容的变化趋势。

The plunger posture may be eccentric and inclined when high-pressure common rail injector is running. In order to study the fuel leakage of plunger pair comprehensively, the mathematical models including Reynolds equation, film thickness equation, cross-section velocity equation, non-isothermal flow equation, steady-state heat conduction equation, and parametric equation of fuel physical property were established. The numerical analysis was conducted based on the finite difference method. The fuel leakage rate was calculated by using the mathematical model and compared with that calculated by the classical formula and the test value, which verified the validity of the model. The trends of leakage rate, film thickness, temperature, density, viscosity and specific heat capacity for gap fuel were acquired in the inclined and eccentric state of plunger sleeve.