Simulation Of Vehicle Performance And Simplification Of Engine Operating Points Corresponding To A Driving Cycle

In modern times, computer simulation is important method and tool for vehicle technology study and vehicle design. It has been widespread adoption during every stage of vehicle design. Vehicle performance can be predicted exactly by simulation before it was manufactured, valuable advices for matching between vehicle, engine and transmission system can be obtain from simulation, then the optimum between dynamic and fuel economy can be obtain. As to traditional vehicle, engine is the only power source, and it is also the direct consumer of fuel and direct producer of emission, so it influence vehicle performance significantly. Fuel economy determined by engine fuel consumption during the driving cycle, so obtain the frequently-used operating points and optimize engine performance particularly are important for vehicle fuel economy optimization. However, engine operating points corresponding to a vehicle’s driving cycle are usually spread in a wide speed and load range and in somewhat a chaos manner; it is difficult to detect the contributions to the overall vehicle fuel economy of each individual operating points. This thesis is focused on developing an approach to simplify the engine operational map into several typical points so that to make it possible for emphasized analysis and optimization.Firstly, represent actuality about vehicle performance simulation and engine operating points corresponding to driving cycle simplification were discussed, deficiency of software existed was detected, then significance and purpose were put forward.Secondly, kinetics and kinematics of vehicle were discussed; theory of vehicle performance simulation was obtained base on vehicle performance evaluation criterion. According to theory of cluster analysis and characteristic of engine operating points, simplify and analyze method of engine operating points were put forward. And computation program was written in Excel-VBA.Then a vehicle dynamic and fuel economy were simulated in the computation program, and engine operating points corresponding to driving cycle were simplified. Compare simulation result with test result and simulation result of GT-Drive, correctness of theory and accuracy of computation program were validated.Finally, according to task of each stages during vehicle design, value and usage method in each stages were presented. This work showed that the computation program can be effectively used to predict vehicle dynamic and fuel economy; it can also be effectively used to analyze engine operating points corresponding to driving cycle. Then correctness and rationality of theory were validated.