Research On Modeling, Simulation And Verification Of Vehicle Start/Stop System

As people’s concerns for environment and consumption of fossil energy continue to rise, the research for energy saving and emission reduction of the vehicle attaches more and more attention. Because of the low assembly cost and better fuel efficiency, Start-Stop system gets much attention and grows rapidly. Since start-stop system controls the engine’s working condition, it has a great effect on vehicle’s performance as well as the equipment and systems used for energy supply. Therefore, the system need to be attached much importance and has a larger improvement space. Combining the theoretical research and practical needs, this paper studies the control strategy of start stop system and establishes a model for it, also the paper improves the original vehicle dynamics model of the laboratory, builds the simulation and verification platform for the start-stop controller and completes demonstration and evaluatio n for the start-stop system.This paper has completed the following work:1. Research for the control of the start-stop system as well as the associated interfaces with other systems of the vehicle. The paper analyses the control strategies and logic relation of the controller, also the relationship between the input and output signals. Then the paper summarizes the associated interfaces between start-stop system and other systems. In this paper, these signals are classified into two categories: one is the dynamic model related variables which reflect the running state and input state of the vehicle and engine, the other is the associated system signals which are input by sensor.2. Establish a start-stop controller model in the MATLAB/Simulink environment. Based on the analysis of the control logic, the paper introduces the construction process of the model, the control strategy of the model is verified by the method of simulation input.3. Improve the vehicle dynamic model, especially rebuild the powertrain system of the model. The main improvement principle is to meet the demand of start-stop system transient model of demand, and satisfy the principle of signal integrity, build model for the missing part. The result shows that the model improved could meet the demand of transient dynamics, and could achieve real time simulation with start-stop system, also meet interface requirements.4. Based on the S-Function function of MATLAB/Simulink, the paper builds the simulation platform, and achieves the joint simulation of the start-stop controller model and the vehicle model, also the paper has completed evaluation of start/stop system using differe nt methods.