Research On The Influence Of Transmission Lubricant Oil Consumption Of A Certain MPV Vehicle

With the continuous growth of China's automobile ownership,there has been a significant increase in oil consumption and exhaust emissions,and resource shortages and environmental pollution problems have become increasingly serious.In order to alleviate these problems,our government has issued a series of stringent fuel consumption and emission standards.One of the research projects of automobile energy conservation and consumption reduction is to improve the transmission efficiency and thus improve fuel economy of the vehicle by optimizing transmission lubricating oil.Based on the research background of the National V Standard,this article takes a three-axle and five-speed manual transmission mounted on a certain brand of MPV models as the research object,combined with theoretical research,proposes an optimization scheme for transmission lubricating oil,and prepares a variety of transmission lubricants,which are verified its tribological performance through tribological experiments,and then through the bench test of transmission efficiency and the test of vehicle coasting and fuel consumption to analyze the impact of different formulations of lubricants on transmission efficiency and vehicle fuel consumption,and screen out the best transmission lubricants.The main research content of this article is as follows:(1)According to the type and structure of the transmission,the lubrication system and lubrication status of the transmission are analyzed,and the power loss composition of the transmission is analyzed in detail.The theoretical solution to the power loss is established for the gear and the bearing,and the mathematical model of transmission efficiency is obtained.And proposed measures to improve transmission power loss through the optimization of lubricant quality specifications,viscosity grade,and additive optimization.(2)Describes the classification standards for transmission lubricating oil quality specifications and viscosity grades,analyzes the composition and the main physical and chemical indicators of lubricants,and elaborates the process of preparation of candidate lubricants,including base oils,sticky index improvers,and composite additive packages.The tribological properties of different candidate lubricants were tested by four-ball test,SRV high-temperature friction wear test and SEM energy spectrum test.The tests showed that the tribological properties of the seven lubricants met the requirements of the transmission.Five lubricants were initially selected for follow-up tests based on the results of the tribological test.(3)The test principle,the overall structure of the test bench,the test equipment and parameters of the transmission efficiency test under normal operating conditions and NEDC conditions are described in detail.The selection of working points and the determination of the test plan are performed in combination with different working conditions.The influence of five different formulations of lubricants on transmission efficiency after initial screening was studied.The results show that the four test oils can improve the transmission efficiency of transmission to a certain extent compared to the original oil.Among them,the 6# lubricant has the best effect and the maximum improvement rate can reach 1.31%.(4)Vehicle coasting and fuel consumption tests were conducted for five types of lubricating oils.Detailed analysis and control were conducted on the accuracy and consistency of the tests.The results of the transmission efficiency test and the vehicle fuel consumption test under the NEDC operating conditions were compared and analyzed.The results show that the addition of friction modifier can reduce the fuel consumption of the vehicle to a certain extent,but the effect of stick-finger improver is better.Among five lubricants,the fuel saving rate of 6# lubricants is 1.89%.Considering cost,performance and other factors,6# lubricant should be the first choice for the company's transmission-matched lubricant.The test results of vehicle coasting and NEDC fuel consumption test and transmission efficiency test have good consistency.When the transmission efficiency is increased by 1%,the comprehensive fuel consumption is reduced by about 0.12L/100 Km.