Research And Test On Transmission Resistance Of Subcompact Vehicles Based On Chassis Dynamometer

The resistance of automotive driveline influences its performance, transmission efficiency and vehicle fuel losses. Along with the country’s gradually improving requirement for vehicle emissions, it is becoming increasingly important to promote the transmission efficiency and decrease the transmission resistance of vehicles. This paper mainly focuses on the large resistance and the short distance of some certain subcompacts and try to exploring appropriate solutions by theoretical analysis and combination of modeling calculation and experimental verification and by using chassis dynamometer to test the resistance performance and research analysis to obtain the variation and distribution regularity, analyze the improvement possibility and direction of the driveline and promote the transmission resistance of vehicles. The results of this dissertation are as follows:(1) Establishment of the model of vehicle road resistance; Analysis of the resistance influence on economical performance of vehicle fuel and the determination of testing transmission resistance by chassis dynamometer.(2) Determination of the testing methods—single point speed state test and taxiing test; Analysis of test principle and formulation of detailed test procedures; test of resistance character and variation regularity of transmission components by using gradual disassembly method to obtain the test data and variation regularity of transmission resistance. Real vehicle test of the road glide resistance to obtain the resistance and glide distance.(3) According to the test data of chassis dynamometer, we can get the function relationship between resistance change of the transmission components and the vehicle speed to get transmission resistance state test and the resistance curve of glide test and then establish the curves of resistance change and distribution.(4) Compared with competing vehicles, by analyzing the resistance distribution we know that objective vehicles’ braking system has larger resistance in non-braking situations; Drive axle resistance accounts for a larger proportion of transmission resistance and has greater effects on character of transmission resistance; braking system and drive axle is the prime component of transmission resistance.(5) By improving the half shaft structure of drive axle, the positioning way of half shaft bearing was changed to prevent sideslip and excursion and to improve the working situations. The drive axle lubricant conditions were changed and gear oil which has smaller resistance and better lubricant ability was chosen by ARKL test and evaluation on drive axle gear oil. The processing accuracy and assembly quality was strictly controlled to ensure the assembly gap between brake shoe and brake drum in non braking situations. Experimental tests show that after transmission components’improvement and optimization, the transmission resistance was significantly reduced, which lays the foundation for subsequent development and transmission system optimization of vehicles.