Research On Friction Characteristics Simulation And Oil Optimization Of Turbocharged Engine

Due to environmental pollution and the oil energy crisis,my country has issued strict regulations on fuel consumption and emissions.In order to meet the requirements of regulations,automobile companies carry out research on various energy-saving and emission-reduction technologies.Oil formulation optimization has a high benefit-tocost ratio compared to other technologies.This paper takes a turbocharged engine as the research object,establishes the engine friction model,and studies the effect of low viscosity of oil on the friction loss of the engine through simulation.Optimize the oil formula,prepare 0W20 test oil for tribological test and fuel economy test,study the anti-friction and fuel-saving effect of oil,and use GED durability test to verify the reliability of oil.The main research results of this paper are as follows:(1)Engine friction model was established,which includes the friction component of the reciprocating component,the friction component of the crankshaft component,the friction component of the valve train and the friction component of the accessory.Considering the viscosity-temperature effect of oil and the temperature difference between different parts of the engine,different viscosity scale factors are used to correct the friction components.R-desk was used to simulate the influence of oil viscosity on the friction components of the engine.The results show that compared with 5W30 oil,0W20 oil can reduce the overall friction of the engine by 5%～8%.(2)The composition and function of engine oil are analyzed,the mechanism of action of friction modifier and viscosity index improver is studied,and an optimization plan for engine oil formula is formulated.Carry out MTM test and ring-liner tribological simulation test for 5 types of 0W20 test oils.The MTM test results show that the viscosity index improver and Mo DTC can reduce friction,and the borate detergent can improve the friction reducing effect of Mo DTC.No.4 and No.5 oils have a significant friction reduction effect under high temperature and low speed conditions,and the friction reduction range is more than 22%.The results of the ringliner tribological simulation test show that,compared with the original oil,No.5 oil has the best anti-friction effect,and the average friction coefficient is reduced by62.24%.(3)Fuel economy index of test oils was carried.Formulate the whole vehicle WLTC fuel economy test process and test it.Based on the vehicle WLTC test,the engine WLTC transient condition is established,the engine WLTC test bench is developed,and the test process is formulated.Test with test oil and verify the stability of the test results.The results show that low-viscosity oil can improve the fuel economy of the engine and the whole vehicle to varying degrees,and the No.5 test oil has the best fuel-saving effect,which is 1.20%;the engine test and the vehicle test can clearly distinguish the difference of the oil formula;the correlation between the two test methods is strong,and the engine test can replace the vehicle test to a certain extent,shorten the test period and reduce the test cost.(4)The reliability of No.5 oil was verified by the engine GED durability test.The results show that the dynamic performance of the engine using No.5 oil is only slightly decreased before and after the endurance test,and the wear of engine parts is within an acceptable range.