Research Of Oil Pump Pressure Pulsation And Flow Stability

In the engine assembly lubrication system, the flow and pressure pulsation ofthe oil pump are instable in the running process. Improving the stability of the flowand pressure of the oil pump is the key scientific issue that engine lubrication systemneeds to solve. So it has great theoretical and practical values to discuss.The researchobject of this paper is gear-type oil pumps. Through combining the numericalsimulation and experimental study, gear parameters, pump structure and flow channeldesign which influenced by the flow stability and pressure pulsation of the oil pumpare analyzed theoretically. The work completed is mainly from the followingaspects:1. The working principle and structure of the oil pump is described. Theimportance of the flow characteristics of the oil pump is elaborated. The influencingfactors of the oil pump flow are analyzed.2. CFD dynamic simulation and within meshing method are adopted. Fluentsoftware simulates the dynamic motion of the internal fluid rotation of the oil pump,pressure distribution and velocity distribution of the pump at different instantaneousare analyzed.3. Simulating the pressure and flow changes of the oil pump whose enginelubrication system is in different operating conditions.4. The models and analysis methods which influence the oil pump flow areestablished. By comparative test on pressure limiting valve, the important factors thataffect the oil pump flow and the method that can maintain the stability of the oil pumpflow and prevent pressure pulsation are identified.Through going into this study, the following conclusions are acquired:(1) According to the simulation results, while the gear which gets into the engagereduces the surrounding volume, the pressure increases; while the gear whichdeparting from the engage increases the surrounding volume, the pressure decreases.From the local velocity vector, we can see the speed is sharply increased in two toothgear.(2) The pressure limiting valve of oil pump has a huge impact on the pressurefluctuations. Spool with steel ball is better than in taper. The opening pressure of theoil pump and flow stability can be greatly improved by spool with steel ball. (3) The flow of oil pump increases by the increase of tooth width and the oilchamber diameter. However, it will lead to lower the strength of product structure,raise the costs, and increase the difficulty of process route. Increasing the pressure ofgear angle, the flow increased fastly. What’s more, the best way to optimize design isnot to change the shape and structure of the oil pump.(4) Through analyzing the experimental data, pump flow is more stable when thegap of the shaft and the supporting hole is0.02-0.03mm.