Design Of Electronic Control Unit For Electric Supercharger

Humanity has never been so concerned about environmental pollution and energy issues. Because of its good thermal efficiency and fuel economy, diesel engine has been widely used in many industries. However, compact with gasoline engine, diesel engine has more NOx and soot emission, which will seriously impact on human health. In particular, when turbocharged diesel engine is under accelerating operation, there is a lot of transient black smoke emitting from diesel engine, since turbocharger can't response quick enough to match the rapid increase in fuel injection. It is necessary to decrease the black smoke. Installing electric supercharger to the diesel engine is one of the important methods to reduce accelerating black smock. Timely control of the electric supercharger is the fundamental gurantee of this work. What is this paper discussed is about the optimal design and experiment research of electronic control unit used for the electric supercharger system to reduce black smoke emission of diesel engine.Previous work showed that the motor was under high temperature after a long time frequently operation. While the high temperature would make the viscosity of lubricant decrease and then the motor's lifetime would be shorted. So a motor cooling system has been installed and a display equipment to monitor the speed of compressor has been considered in the newly designed electronic control system. In order to design the electronic control unit, firstly, the control strategy has been developed and the hardware circuits of each function modules have also been designed respectively. Considering the electromagnetic compatibility, some methods have been used, such as adding some capacitors have been chosen as a function of filtering and decoupling interference to enhance the hardware anti-jamming ability of the system. The software is divided into three functional modules: compressor drive module, motor cooling module and compressor speed display module. Modular principle, top-down and progressive refinement technologies have been used to design the software, while software filter and"watchdog"technology have been used to enhance the software anti-jamming capability. The three functional modules of the system have been tested and system reliability preliminary test has been conducted on the bench. As both results were satisfactory, the system has been installed on a bus for on-board test. On-board test result shows that under the control of the designed electronic control unit, the electric supercharger system obviously reduced the black smoke emission from diesel engine; The speed of the compressor can reach to working stage in 1.3 seconds; the motor worked in the permitted temperature range. In addition, seven months'path tracking test has been conducted to see the reliability of the unit, results show that the electronic control unit adapted to the bus working environment and it had strong anti-jamming ability to meet the reliability requirements.