Research On The Control Strategy Of Engine 48V Start-stop System

As the implementation of the fuel consumption regulations and policies of the government,a lot of kinds of fuel-saving technology are launched with the increasing pressure of enterprise.Among them,Most of the auto enterprises are interested in the48V technology as a short term rapid technical solution.The fuel-saving rate of 48V technology is better than traditional start-stop system,because the strategies are optimized and upgraded.In addition,48V technology avoids the technical risks of the high-voltage BSG system and decreases the system cost.In the Domestic auto enterprises,48V technology architecture are basic same,but the differences in functions and control strategies.The text researches on the Control Strategy of Engine 48V Start-Stop System which belongs to P0 structure Mild Hybrid system.BSG motor was connected to the engine by a belt,the system control strategy is integrated in the vehicle control unit.First of all,the belt transmission ratio was setted and the selection of motor and battery was done based on the system functional requirements.Secondly,according to the analysis of the data of traditional start-stop control system,the control strategy was optimized and the coordinated control strategy of correlation system was defined.In addition,the energy recovery control strategy was optimized based on the existing hybrid control strategy and a two parameters control strategy based on the target SOC and the velocity was put forward for torque assistant function in this text.Then,the complex method is adopted to control parameters optimization design,taking Cruise and MATLAB/simulink software co-simulation as the platform.Finally,the control strategy validation test is done through the vehicle fuel consumption test.In accordance with the regulation,the NEDC cycle is still used to do the fuel consumption test.The actual test fuel consumption of the vehicle equipped the 48V start-stop system which is studied in this text is 6.95L/100 km,the original car actual test fuel consumption is 7.55L/100 km,fuel-saving rate reaches 8%.The cycle fuel consumption would satisfy the 3^rd phase fuel consumption regulations if the 48V start-stop system were used.