Study On The Flow Characteristics Of Residual Oil In Retired Passenger Car Engine

In recent years,China’s car ownership has exploded,and the number of retired passenger cars has also increased rapidly.Efficient discharge of engine residual oil has always been one of the challenges faced by end-of-life passenger car recycling.In the traditional engine residual oil recovery method,the internal oil of the engine is discharged from the oil discharge port under the action of gravity,the efficiency is low,the oil is difficult to discharge completely,and the risk of environmental pollution is high.Therefore,it is urgent to carry out the research on the mechanism and equipment of rapid discharge for the residual oil of passenger car engines.This paper aims to achieve the rapid discharge of lubricating oil inside the engine.This paper has carried out research on the basic characteristics of lubricating oil and its rapid discharge mechanism,and the main contents as follows:1.The viscosity properties of lubricating oil and the main factors affecting the viscosity under different usage conditions are analyzed.Then,through XRD phase detection analysis,the composition of impurities contained in the residual oil sample was obtained,which provide data support for numerical simulation analysis.The study found that the viscosity of the lubricating oil is related to the carbon content in the impurities.The higher the carbon content,the greater the viscosity.2.The engine oil lubrication system is consist of two parts,the watershed formed by the cylinder head and cylinder cover,and the internal watershed formed by the engine block.There are many branches in the lubrication system.How to establish a residual oil flow system model is the key to the numerical simulation research.The thesis takes an in-line four-cylinder gasoline engine of a passenger car as the research object,and the lubricating system model of the engine is extracted based on Solid Works and SCDM software,which lays the foundation for the development of oil flow characteristics.3.Based on the Fluent software,numerical studies are conducted on the flow field of the internal oil of the engine under the action of gravity and compressed air.The results show that the oil takes a long time to evacuate by gravity in the entire engine watershed,about 80 minutes.In the state of applying compressed air,the greater the inlet pressure value,the shorter the oil discharge time,the more obvious the internal turbulence phenomenon,mainly concentrated in the area near the oil return channel and the oil discharge port.When the air pressure is 0.7MPa,the adhesive force of the oil flowing on the wall just reaches the critical value,and the oil can be discharged quickly.When the air pressure is 0.8MPa,the oil is compressed into the corner area,and the exhaust time increases instead.4.Based on the foregoing research,combined with the study of the engine oil injection port characteristic parameters,a rapid oil discharge device suitable for retired passenger car engines is designed.The device is mainly composed of lifting device,air compression device,air delivery pipeline,interface device,support platform and control device.The platform can shorten the discharge time of engine residual oil from 80 minutes to 15 minutes,improving the efficiency of oil discharge.In summary,the thesis provides theoretical and numerical simulation references to the studies for residual oil flow characteristics of retired passenger car engines,as well as provides theory and method supports to the high efficiency,environmental-friendly and safety recycling of retired vehicles in China.