Research On Parameters Matching And Optimization For Power Transmission System Of LNG Heavy Truck

To achieve the diversification of motor fuels is an important way to solve the problem of environmental problems and energy supply. Natural gas has gradually become an important alternative fuel because of its low pollution,rich resources and low price, so that the liquefied natural gas(LNG) vehicles are valued and rapid promotion. LNG heavy truck as a kind of new energy vehicle, optimizing the parameters of automobile power transmission system can improve the performance of the whole vehicle. Based on the LNG heavy truck as the research object, the performance evaluation index of the vehicle is analyzed, and the characteristic curve of the engine is fitted, and the whole vehicle simulation model is established, then established an optimization mathematical model to improve the fuel economy targets, and the optimized model is simulated. The following research work has been done:Firstly, based on the existing evaluation indexes, the comprehensive indexes reflecting the two indexes are put forward. Using the proposed method can integrate the existing discrete data into continuous surface data.Secondly, according to the power transmission line of the LNG heavy truck, heavy truck LNG vehicle simulation model has been established using the AVL-CRUISE software. The LNG heavy truck’s basic performance were simulated, and deviation between the results with factory data is small, so the model is very accurate, then analyzed to verify the accuracy of the simulation model. And then, establish the LNG heavy truck mathematical optimization model, and regards LNG heavy truck transmission and main reducer transmission ratio as design variables, C-WTVC driving cycle fuel consumption and constant speed fuel consumption as Optimized sub target.The multiple objective function is transformed into a single objective function by introducing the weighted coefficient, and the penalty function method is used to solve the problem.Finally, putting the optimization of transmission system parameters into cruise model, setting calculation task, and then the vehicle performance of LNG heavy truck is obtained after running. Compared with the original car,in addition to the maximum speed decreased, the other properties are improved in different degrees. It shows that the method can complete the task and achieve the goal of optimization.