Parallel Hybrid Off-Road Vehicle Simulation And Research On Vehicle Control Strategy

Because of the excellent dynamic performance and passenger space, off-road vehicles have gained an increasing popularity among consumers. Its development, however, has been restricted by high fuel consumption and high emissions. At present, researches on hybrid electric vehicles (HEVs) mainly focus on cars and buses rather than off-road vehicles. Hybrid electric technology can not only enhance dynamic performance but also could be fuel-efficient. This paper attempts to analyze some certain parallel schedule HEV, studying relative modules and control strategies and modeling before the real vehicle-related tests are finally introduced. Vehicle road test is done to verify control strategy for validation step and results is very close to simulation results. The main contents of every chapter are as follows:(1)This thesis describes the background information and significance of the development of off-road vehicles at home and abroad at first, then analyses the feasibility of hybrid technology in off-road vehicles and the key technology, then proposes its own research method and work on this issue.(2) Experimental method, supplemented by theoretical method, is used to establish facing-forward simulation model in Matlab/Simulink environment, including driver model, engine model, motor model, battery model, transmission system model, vehicle longitudinal dynamics model and electrical accessories model, thus creating a necessary simulation platform for the study of vehicle control strategy.(3) Based on the simulation platform, the author continues to study the logic threshold control strategy and its design of parallel hybrid off-road vehicles. Then, this paper analyses the energy management strategy of parallel HEVs and the transition conditions of different operating modes on the premise of the working model of hybrid power system. The control strategy is established to meet the basic condition of five kinds of hybrid vehicle and switching for improving the vehicle fuel economy. The results prove the effectiveness of control strategy and improvement of fuel-efficiency compared with vehicles of original type.(4) The paper uses data of NEDC cycles to carry on software simulation and compares the economic performance of off-road vehicles with that of the traditional off-road vehicles of the same type. The results show that the off-road vehicles models and hybrid power simulation system are reliable with the effectiveness of control strategy and an increase of fuel efficiency.(5) Real vehicle test. The control strategy is downloaded into RCP(Rapid Control Prototype) ECU. The test results of the design of the vehicle control strategy show the accuracy of the algorithm and the superiority over traditional vehicles of the same type in overall performance.