Research On Energy Flow Distribution Test And Algorithm For Passenger Car

The fuel economy is an important performance index of vehicle.The energy distribution scheme from the whole vehicle to the components & parts can provide the effective selection basis for vehicle performance matching.This paper constructed the vehicle energy distribution models,including the chemical energy,the thermal energy,the electrical energy,the mechanical energy,etc.Then the model parameters were identified based on the test data obtained from the whole vehicle tests.In the end,the detailed energy flow distribution was quantified finely and accurately.This study provides a theoretical and data means for the whole vehicle development,which has important theoretical meanings and practical values.The main research works are as follows:(1)Vehicle energy transmission characteristics analysis and its algorithm design.The energy for the detailed components and parts were analyzed qualitatively and quantitatively,and the algorithma for the chemical energy,the thermal energy,the electrical energy,the mechanical energy,etc.,were designed for the corresponding components and parts,such as the engine,the gearbox,the tyres,and so on.In addition,the temperature effection was taken into consideration in the mechanical energy algorithma.The influence of wind speed on the heat dissipation capability for the detailed components and parts was considered in the thermal energy algorithma,in which the heat radiation and the heat absorption were distinguished.Similarly,the basic electrical equipment such as ECU was included in electric energy algorithma.(2)Test design for the energy model of the whole vehicle and its components and parts.The concrete work included the selection and consturciton of the test equipment,the design of test principle and test method of vehicle components and parts,etc.,which provided the accurate and reliable parameters for the energy flow distribution calculation,such as the coastdown resistance,the wind resistance,the radiation and heating coefficient,the wind speed field,the heat dissipation coefficient of the radiatior,the power generation efficiency of the generator,the power consumption of the electrical equipment,and so on.(3)Energy flow calculation software development based on LabVIEW.The tree graph,the pie chart and other ways have been employed to show the calculation results.The software can calculate the total energy ratio and instantaneous ratio of the mechanical energy,the chemical energy,the thermal energy,the electrical energy,etc.,for the whole vehicle or each component & part.Besides,the software builds the performance database of the whole vehicle and components & parts,which helps to comparative analysis the vehicle dynamic and economy performance.(4)Real vehicle tests.The performance tests of NEDC driving cycle have been done in the dynamometer.The key parameters,such as the instantaneous fuel consumption,the fuel consumption of 100 km,the generator and battery current,the temperature of engine and gearbox,and so on,have been used to verify the accuracy of the energy flow algorithm and the reliability of the developed software.The results show that the energy flow algorithm is scientific and reasonable and the software runs stably.