Study On Reliability Test For Commercial Vehicle Hybrid Powertrain And Design Of Measurement And Control System

Hybrid technology is a crucial strategic choice for commercial vehicles to achieve the goal of saving energy and reducing consumption,and will also become the mainstream technology route in the field of commercial vehicles.Due to the long-term high-load operation,diverse working modes and complex driving conditions of commercial hybrid vehicles,higher requirements are also placed on the reliability of the hybrid system as its core part.Therefore,it is very necessary to accurately verify the reliability of the commercial vehicle powertrain before the development of the powertrain is completed.However,the existing domestic commercial hybrid powertrain reliability test standards are not complete,and there are still few studies on effective assessment mechanisms and test methods for the reliability of commercial vehicle powertrains.Reliability testing of the engine or electric motor in a hybrid powertrain alone will have certain inaccuracies.Therefore,this paper studies a reliability test method of hybrid powertrain,and designs a modularized measurement and control test bench for the reliability test of commercial vehicle hybrid powertrain.This will help shorten the research and development cycle of commercial vehicle powertrains,and provide some technical references for the formulation of my country’s hybrid powertrain reliability test standards and the manufacture of automobile enterprises.This paper firstly analyzes the structural characteristics of a commercial vehicle hybrid powertrain with a dual planetary gear set power coupling type.Based on the principle of lever method,the mathematical relationship between the rotational speed and torque of each power source in the hybrid powertrain is established,and the energy flow transmission path of the hybrid powertrain in various working modes is analyzed.Combined with its coupling system operating characteristics,this hybrid powertrain reliability test condition analysis was conducted.Secondly,the hybrid powertrain load spectrum compilation scheme is formulated.Based on the mechanical point(MP)control strategy with the optimal transmission efficiency of the hybrid powertrain,the load spectrum of each power source is compiled by means of co-simulation.According to Miner criterion,the cumulative damage ratio of each power source is calculated by using the statistical method of amplitude counting,and the reliability test condition is designed according to the damage ratio.After completing the design of the loading conditions,according to the reliability test requirements and the functional requirements of the measurement and control system,the hardware selection of the measurement and control test bench is carried out,and the overall design scheme of the measurement and control system for the hybrid powertrain is formulated.The measurement and control test bench adopts the DC bus feedback variable frequency control system,and uses the Siemens software STARTER and Portal V16 to complete its hardware equipment configuration and lower computer program design.The host computer software is designed with Lab VIEW software for the parallel multi-thread architecture,which mainly includes the user login management subroutine,the test process setting subroutine,the parameter setting program subroutine and the motor control subroutine.The data transmission between epigynous machine and hypogyny-machine is realized through the OPC communication protocol.Finally,a design test scheme is designed with reference to the relevant domestic standards for the reliability of this hybrid powertrain.After completing the construction and functional verification of the measurement and control system test bench,the initial performance test of the hybrid powertrain is carried out and the reliability test is carried out according to the test process.