Load Spectrum And Application Of PHEV Powertrain

With the increasing development of the automotive industry,the power demand for vehicle is changing due to the natural energy resources on Earth and the need for environmental protection.For traditional cars,it uses fuels such as gasoline,diesel,natural gas,which makes environmental pollution increasingly serious,then many auto companies focus on the more environmentally friendly energy-saving hybrid vehicle,as well as pure electric vehicles as the direction of future development in.For hybrid vehicle,because the electric power system and engine used in the motor at the same time as a power output,and the hybrid vehicle power system work mode is more complicated than the traditional one compared to conventional automotive components.So for a hybrid vehicle,bench test loading method for traditional auto parts can not test whether the parts of the life is qualified for car drive system accurately,so we can not make the accurate evaluation to spare parts for the hybrid vehicle.In this paper,I will study and explore the load spectrum of the vehicle-driven system bench test for a PHEV powertrain system through the load spectrum of the dynamical system.main contents of this paper are as follows:1)Data acquisition of PHEV road actual conditions.As a result of the development of PHEV powertrain load spectrum,we will proceed from the actual and select part of the typical road of Changchun City,through the collection of CAN signal to the powertrain load.At the same time,check the conformity of the collected data to ensure that the selected sections can accurately represent the daily working status of the PHEV power system on the road,thus ensuring the typicality of the data.2)Determination of the minimum number of test cycles.Firstly,the data are divided into 35 categories according to the different working states of the power system,and the data of the engine and the motor are processed with simple data.The subjective weight method and the entropy method are used to determine the subjective and objective weight coefficients,and then the final weight is obtained by the linearweighting method coefficient.The number of collected data is weighted to obtain the minimum number of test cycles,and the data is merged to obtain the minimum sample size so that the required data can be collected accurately and efficiently,and the cost of the experiment is greatly saved.3)Load spectrum of PHEV powertrain dynamic system.The minimum sample data is grouped based on the different modes of the hybrid system's several operations.The engine torque,motor torque,and motor negative torque three categories respectively.Then,the two-dimensional load spectrum of the engine and the whole life of the key components of the PHEV powertrain is obtained by using the rain flow counting method and the nonparametric extrapolation method.Then,the one-dimensional load spectrum of the amplitude is obtained by the equivalent transformation of the non-uniform stress.Finally,the eight-level load spectrum is calculated by the equivalent damage principle and Miner criterion.4)Develop of PHEV transmission system indoor bench reliability test conditions.Based on the analysis and analogy of the industry standard QC/T926-2013 for the reliability test of the hybrid powertrain,and according to the actual PHEV load spectrum,the original test condition is adjusted by using the damage principle,to develop test conditions which are more suitable for PHEV transmission system of indoor reliability.