Development Of The Infineon XC2785X Based Electronic Control Platform For SCR System

In order to preserve the natural environment which the humans must rely on，and solvethe increasingly serious problems of the global environmental pollution, governments haveintroduced a series of stringent vehicle emission regulations. In our country, with theNational IV and V emissions standards promoting, the control technology aimed at reducingautomobile exhaust has also become an important topic for research. At present, merelyrelying on internal purification technology has been too difficult to meet strict emissionregulations, so auxiliary effective aftertreatment technologies must assist in accomplishingthe arduous task, including Selective Catalytic Reduction(SCR). Because of its excellent fueleconomy and high NOXconversion efficiency, SCR has been recognized as a main controltechnology for the aftertreatment of the Diesel Engine.With references to the foreign advanced development solutions for automotiveelectronic control system, and a detailed anslysis of the needs of the domestic developmentof SCR electronic control system, this thesis proposes a complete set of design project forSCR system platform，which has been realized based on Infienon XC2785X. The primaryworks are presented as follows:1. This thesis focuses on the mainstream SCR system of Diesel Engine, including itssystem composition, working principle and the main chemical reaction process. According tothe complexity of the SCR algorithm and the requirement of of single-chip peripherals,Infineon XC2785X has been taken as the core controller for the development platform forSCR electric control system.2. Taking advantages of on-chip recources of Infineon XC2785X, this thesis hasdesigned the hardware circuit of the development platform. It includes not only basic CANcommunication and JTAG debug interface, but also the signal conditioning circuit forcollecting signal of pressure and temperature sensors, the smart low-side drive circuit used tocontrol nozzle and valve, and the H-Bridge drive circuit used to control the pump motor. 3. This thesis has designed the underlying software of SCR system platform. UsingDAvE software as an initial configuration tool, initialization and basic function library ofInfineon XC2785X have been completed. On this basis, by adding the function pointers intoStructures of the C language, an implementation of object-oriented programming by Clanguage has been designed, and the underlying objects in the underlying software have alsobeen packaged. These objects can be easily invoked and applied by upper control algorithms,to enable the safe operation of the hardware resources.4. With Visual C++software, the special upper-computer software is also designed inthis thesis. Through the USB-CAN interface card, it can communicate with the hardwaresystem of the platform, to implement many functions, such as High speed data acquisition,real-time information display, and parametric calibration. The upper-computer softwareprovides a convenient human-computer interface for development of SCR controlalgorithms.5. Within the equipments and conditions in the laboratory, a functional testenvironment has been built. And some tests has been made to sufficiently validate basicfunctions of the platform, including CAN communication, analog signal acquisition, pulsemodulation signal capture, and low-side drive, etc. The results show that this paltform iscapable to properly realize the underlying feature, which can meet the design requirementsand needs of SCR system development.