Design And Test Research On The SCR Electronic Control Unit Of Automotive Electronics

Selective Catalytic Reduction(SCR) is an effective technology to reduce the NOx emission of diesel engines. With the increasingly serious problems of environment and energy, SCR technology will be widely used in medium and heavy duty diesel engines. The market demand of SCR electronic control system will be very large in a long time. Software testing plays a very important role in ensuring the safe and effective operation of the SCR electronic control system. Therefore, it has important practical significance to research and practice the testing of SCR electronic control unit as the core part of the system.This paper is based on the project of "Development and system integration of SCR electronic control unit ". The project is jointly developed by Beijing University of Technology and Baotou Research Institute of College of Engineering,PKU. It breaks through two key technologies, the development of SCR electronic control unit(DCU) for diesel engine and the SCR system integrated matching. And it completes the SCR electronic control unit product. Therefore, the results of this paper's research have important practical application value. In this paper, the main module of the SCR electronic control unit has been designed. And the paper mainly describes how to test SCR electronic control unit effectively. The main results of the research are as follows:1. The hardware design and software integration of DCU. The hardware circuit is designed with Freescale's microcontroller MC9S12XS128 as the core for SCR system, including analog signal processing circuit, switch load driving circuit and CAN communication circuit. The software integration includes the automatic generation of application software and the main modules' compilation of basic software, including the ADC drive module, the PWM drive module, the SCI drive module, the CAN drive module and the storage drive module.2. According to the characteristics of SCR electronic control unit and the status of software testing, the test of the SCR electronic control unit's underlying source code has been researched. The test methods and tools are selected appropriately, and the test plans and programs for the SCR electronic control unit is designed from two aspects of static test and dynamic test. The test content of the static test and the key technologies used in the dynamic test are introduced respectively.3. In the end, the actual test work is carried out, the underlying source code of SCR electronic control unit has been tested from tow aspects of static test and dynamic test. And the test results are analyzed. According to the results, the paper makes rational suggestions for the optimization of the system, and the validity of the test plans and programs is veritied.