Research On Vehicle Mechanical Power Consumption Based On Torque Analysis

The mechanical power consumption of the whole vehicle will affect the economy of the car and reduce the energy utilization rate.This paper introduces the research on the mechanical power consumption of the whole vehicle based on the torque of the half shaft of the vehicle.A pure electric vehicle is used as the research object.First,the half-shaft torque test is carried out to verify the feasibility of the test.The half-shaft torque of the vehicle is tested under cyclic conditions,and then the simulation software is used to build a vehicle energy flow simulation model.Simulation results are obtained and compared with experimental results to verify the accuracy of the model.In addition,the model is used for simulation analysis to study the energy flow of pure electric vehicles and the mechanical loss of the whole vehicle.The main work of this paper is as follows:(1)In order to obtain the torque state of the left and right half shafts in the whole vehicle state under different working conditions,the strain type torque measurement method is used to measure the half shaft torque.Sensors and other experimental setups are designed and carried out according to the working conditions of the whole vehicle,and the obtained measured values are compared with the ECU output torque data to verify that the test program is reasonable and feasible.(2)In the process of building the vehicle energy flow simulation model,the important components of the vehicle model,such as the driver model,the sub-model of the vehicle load,and the vehicle controller model,are modeled first.Then the power transmission system was built and compared with the test results,and the vehicle energy flow simulation model was built at last and compared with the test results.(3)Based on the built vehicle energy flow simulation model,the dynamic performance of pure electric vehicles is analyzed for different cycle conditions,transmission ratios and temperatures.Vehicle mileage,battery SOC,and mechanical power consumption were also studied.The research results show that the half-shaft torque test scheme is feasible,and the whole vehicle energy flow simulation model is accurate.The analysis results of the model show that the mechanical loss first decreases and then increases with the increase of the rotational speed,when the half shaft torque is constant.When the motor speed is low,the mechanical loss decreases with the increase of torque until it reaches the minimum loss value and then tends to be stable.When the speed is high,the loss first decreases and then increases with the increase of torque.Under high and low temperature working conditions,the vehicle mileage attenuates seriously under equal energy consumption.The energy loss of the vehicle is greatly affected by temperature,and the lower the temperature,the greater the mechanical loss.