Design And Study On Hybrid Power System Of The Startstop System Of Engine

Start-stop system can reduce the idle state of the car, it is conducive to save fuel and reduce emissions. In many energy conservation and emission reduction technologies, the Start-stop system is a simple and effective one, with the continuous emission regulations strictly, the application of the Start-stop system is becoming more and more common. At present, the application of lead-acid battery in the starting and stopping system has the problems of low start-up capacity, low battery life, excessive starting transient voltage drop and so on. Other automotive power supply, such as lithium battery, AGM from the battery are too high cost or the effect is not obvious and other issues.Firstly in Beiqi E150 real vehicle were starting test, through the normal starting about the change process of the starting process of voltage, current and power output. In order to prevent the impact of starting work on observation of the effect of the engine, close the pump and generator of starting test. Provide the basis for modeling behind starter.Then the composite power supply combined with general lead-acid battery and super capacitor is designed based on the starting and stopping system. Series hybrid power the leadacid battery and super capacitor in series for starter power supply, and control unit is designed to realize the control of super capacitor on and to the super capacitor charging function. Composite power supply parallel scheme using ordinary lead-acid battery and super capacitor connected directly to supply power to the starter, batteries and capacitors always connected, two terminal voltage consistent.The equivalent circuit model of lead acid battery and super capacitor was established in Simulink. The model parameters were calibrated by charge discharge experiment, and the accuracy of the model was verified. Using the DC machine module in Simulink starter model. The model can reflect the change of voltage, current and crankshaft speed in starting process system.The different parameters effect on the priming effect, such as: battery voltage, line resistance, battery internal resistance, resistance torque and moment of inertia, are investigated in detail through model and experiment. The parameters such as voltage, capacitance and voltage in series are determined by the model. The discharge characteristics of the battery and capacitor are studied by experiments. Finally, the experimental results show that the hybrid power supply can significantly improve the starting performance compared with the conventional lead-acid battery.