Research On The Development Of The Vehicle Low-temperature Preheating System

With the vehicle widely used in the world,its working environment is in a large scope.The performance of the vehicle are seriously affected by the heat problem of vehicle system and its components,especially in the extreme temperature environment.The problem includes heat transfer problems in the low temperature and high temperature environment.And the solution of these problems is mainly depended on the technology of thermal management to make the thermal requirements of vehicle components and systems satisfied.As the vehicle technical level gradually improved,more attention is paid on the vehicle thermal management,and becomes an important research direction in the new energy technology field of vehicle.In this thesis,the main direction of vehicle thermal management research is design and development a low-temperature preheating control system for a certain truck.The main content of the thesis include: analysis and design the preheating system for the specific vehicle,develop the control strategy and computer-aided one-dimensional simulation,embedded MCU development based on C language and experiment evaluation.The following are summarized respectively.(1)For the relevant data of a certain truck,its requirements of components and subsystems in low temperature environment are analyzed.It includes strict demand for heat engine cooling system,the cabin preheating system and fuel tank.According to the physical technical parameters of the preheating system,the calculation of the control technical parameters and the matching selection of the pipeline components are completed.(2)According to the program of developed and designed vehicle low-temperature preheating control system,this paper analyzes and sorts out the situation of the heating demand in the vehicle heating objects,and puts forward the control strategy matching with the preheating system.This control strategy is mainly divided into the logic judgment on the advanced level and the control algorithm in the local scope.The logic threshold control strategy based on rules is adopted on the advanced level.The fuzzy control algorithm is one of the artificial intelligence algorithms.Both combine to a complete control strategy.They build and develop based on MATLAB/SIMULINK platform.The GT-SUITE/GT-COOL vehicle system simulation software was used to build the one-dimensional physical model of the system.The aforementioned control algorithm software was used to realize joint simulation,so as to provide auxiliary development and verification for the control system.(3)According to the aforementioned control algorithm,the STM32 embedded microcontroller is used to develop corresponding control.Based on the corresponding control model that built in MATLAB/SIMULINK,it is transformed to C language.The algorithm body in the form of C language is written and improved.The matching external device driver is developed and the control function is downloaded and debugged.It builds the experimental simulation platform taking the embedded microcontroller as the control core of the developed system.The vehicle low temperature preheating system is tested.Combined with the aforementioned virtual simulation technology,the control strategy and preheating performance of the system were analyzed.