Performance optimization of an oil ellipse gerotor pump for automotive engine

The internal cycloidal gear pump is one kind of oil pump, which consists of pump body, pump cover and rotors. It is widely used in the range of vehicles. A gerotor pump has various advantages such as compact size lower noise, less emissions and little pressure ripples for circulation of the fluid. In practice, the conventional cycloid rotor oil pump has the problem of exists engaging limit point which results in bad wear of rotors, reduce the volumetric efficiency. For above these problems, we use the higher efficient transmission performance ellipse rotors. After that, we propose a new method of searching a new point in original ellipse profile to remove the engaging limit point. Experimental investigation has been carried out through bench test, and the results show that at the range of 0.5MPa to 2.5MPa, 3% and 5% increase of the volumetric efficiency and volumetric flux of the gerotor pump has been achieved respectively through the optimization of new rotors profile. It explains this method of rotor profile by removing engaging limiting point satisfies he design requirements without any volume size changing.