PERFORMANCE OF GEROTOR OIL PUMP FOR AN AUTOMOTIVE ENGINE - PREDICTION USING CFD ANALYSIS AND EXPERIMENTAL VALIDATION 2009-28-0007

The reduction of development time of new Internal Combustion Engines prototype and reduction of fuel consumption are key issues in automotive Industry. Lubricating oil pump systems having potential of reducing fuel consumption by up to 3% in the new European Motor Vehicle Emission Group (MVEG) Cycle. Oil pump feeds lubricant oil into the parts of engine to prevent wear and to cool the moving parts of the engine. Gerotor pump is a special kind of internal rotary positive displacement pump which is driven by crank shaft. It provides high volumetric efficiency and smooth pumping action, and it works well with a wide range of fluid viscosities. Tip to tip clearance, volumetric efficiency, flow ripple and cavitation damage are causes for concern in Gerotor pump with high output flow. To optimize the pump performance, it is essential to understand the flow dynamics inside the pump.

In this paper, a three dimensional CFD analysis has been carried out to predict the pump performance, understand the pump flow dynamics and to investigate flow ripples of a Gerotor pump. The flow analysis was carried out using STAR-CD. A methodology has been developed inside the software to generate the volume mesh for the rotating gears, since it involves complex mesh motion and physics. Arbitrary sliding interfaces were used to allow the fluid flow interaction between the static and dynamic parts and also between the dynamic parts. Fluid velocity and pressure inside the pump have been predicted to understand the flow dynamics inside the pump. The simulation results were compared with the experimental values and a very good agreement has been achieved