Transmission Efficiency Analysis And Research Of Mechanical Transmission Of A Micro Car

The Transmission is the core component of automobile drive system,which is used to change the transmission ratio of the automobile,interrupt the power transmission and realize the traffic back.At present,the main development trend of automobile gearbox is automatic transmission,but mechanical transmission has the advantages of simple structure,low cost,good versatility and high transmission efficiency,so it still has an irreplaceable position in the future for a long period of time.At present,there are few researches on the transmission efficiency of mechanical transmission,and the most research is about the heavy car.The theoretical analysis and the real vehicle test are used to detect the transmission efficiency for the transmission of mini car.Based on the mechanical transmission of a mini car,literature review,this paper analysis the factors affecting the transmission efficiency,transmission power loss,the calculation formula of transmission efficiency has been obtained.then according to the formula,the power losses of the Matlab/Simulink calculation model is built and analyzes the factors.Then the simulation software Romax is used to build the model of the target transmission,and the transmission efficiency is simulated and analyzed.Finally,a set of mechanical transmission efficiency test bench is designed,which is used to verify the theoretical calculation and simulation results.According to the national automotive industry standard QC/T568.1-2011 /Rig testing method for auto manual transmission assembly-Part 1:mini-vehicle,a set of mechanical transmission test bench was designed according to the national automotive industry standard,which is used to detect the transmission efficiency of the transmission.Considering the environment,the scalability of test bench and the cost,the common DC bus energy feedback electric closed system is used for the test bench,saving electricity.The test bench uses two AC variable frequency motor to simulate the driving and load of the vehicle respectively.The PLC and S120 converter are used to realize the control of the speed and torque of the motor.the data acquisition of the speed,torque and temperature data and the output of the switch control signal are realized by using the NI PCI-6221 data acquisition car.The test bench is reliable,energy saving,and has good versatility and expansibility.It can reflect the change of the transmission efficiency of the manual transmission.The transmission efficiency data are compared with theoretical calculation and simulation results.The final result is that the test bench results and the theoretical results are consistent with the comprehensive efficiency,the error is less than 1%,which provides data support for the theoretical analysis,proves the validity of the Romax simulation model and analysis result.