Development Of Onboard Measurement System For New Energy Vehicles

Road test is an important method in the research and development of vehicles.In order to obtain the vehicle's performance characteristics, an onboard measurementsystem is necessary to collect the operation data. The development of new energy ve-hicles increases the complexity of the environment of onboard measurement systemand bring forward further requirement of the measurement system. This thesis intro-duces the design of an onboard measurement system which bases on integrative virtualinstrument and can be used on both traditional and new energy vehicles.Relevant regulations and measurement method are the basis of vehicle road test.Relevant regulations and measurement method as well as the principle of sensors ofimportant parameters such as voltage and current of storage battery, rotating speed,vehicle speed and fuel consumption are analyzed in this thesis . Proper sensors arechosen and the connection modes are concluded. According to the requirement of rele-vant regulations and the characteristics of sensors, onboard measurement system designrequirement is summarized, which lays a foundation for the practical development ofthe measurement system.Integrative virtual instrument structure is adopted as the main design of the testsystem. Three data collecting methods are used in this measurement system whichinclude system bus, communication bus, communication interface or communicationcard. These methods could realize data collecting function of di?erent data types. Thehardware design bases on embedded PC while the modular software design runs onXPE operation system and LabVIEW.Modular design is also adopted in this onboard measurement system, with variableconditioning and measurement modules based on di?erent sensor signals. The designof the frequency acquisition module is based on synchronous multi-cycle frequencymeasurement while amplifiers and circuit of filter and shaping are adopted in the de-sign of the signal conditioning module. The signals from platinum resistance tem- perature sensors could be conditioned by bridge circuit and/or constant current sourcecircuit, while the latter solves the non-linear problem of bridge circuit. In result, ac-cording to di?erent demands of measurement, the corresponding condition modulesand measurement modules could be selected to realize the modular design of the on-board measurement system.Environmental performance of the measurement system is tested in incubator,while measurement and calibration are processed on the engine testbed and rollingdrum table. Experiments are also taken on traditional and new energy vehicles onthe real road. The result meets the requirements of the measurement. It shows thatthe onboard measurement system operates stably and can be used in road test on bothtraditional and new energy vehicles.