The Research Of The Testing Instrument Of Comprehensive Performance Of Automobile Engine Based On Embedded System

Today the people are continuously raising their demand about automobile dependability, security and green quality. The engine, which is the heart part of an automobile, is the highest fault rate part of the automobile. People have been paying more and more attention to the performance testing of the automobile. The traditional testing instrument of engine performance can not meet the requirements. Therefore it is need to research a new testing system of engine performance, which is advanced, practical and economic. In order to meet the need of the research, development and fault detect of the engine.The target of the task is designing a testing system of gasoline engine based on embedded system. All kind of signal such as secondary ignition waveform, advanced ignition angle, dwell angle, engine gasoline consumption, engine power, engine rotational speed, cylinder pressure can be collected, disposed and displayed. It can also accomplish the serial communication with a PC and the testing data storage.According to the overall needs of system designing, the design scheme based on embedded system was proposed and adopted. C8051F120 is an 8-bit SOC , which is high performance, low consume and full compositive. C8051F120 is suitable to the field with a complex algorithms' structure, and with high calculation speed, and with a large volume of data required to handle, and with high processing speed.Meanwhile, a modular design method was adopted for designing software and hardware, which greatly shortened the development cycle, and reduced the cost of research and development, and achieved good economic benefit. The system is divided into four parts, which are the testing module of secondary ignition waveform, the testing module of power and rotational speed, the testing module of engine gasoline consumption and the testing module of cylinder pressure. The conditioning circuit of each signal such as shaping circuit, voltage-dividing circuit and amplifier and interface circuit of the showing, communications and storage of the data were introduced in hardware. In software, A/D conversion, data processing, data showing, data storage and serial communication were introduced. And procedure flow chart and part of software code were offered.In the thesis we have done substantial analyses and research to be aware of the engine testing requirements and traditional testing means. Basing on this and making use of modern technical in the field of microprocessor, sensor, electronics and software, we developed a prototype. Before the prototype was developed, system designing, hardware choosing, schematic diagram drawing, PCB diagram drawing, circuit board making and testing software programming had to be done. Finally, the performance of an automobile engine was tested by the prototype. And the testing result was contrasted and analyzed with the result which was tested by an advanced and high powered testing system. The testing results show that the prototype has some excellences such as accurate results, high precision, steady performance, friendly interface, intuitionistic data showing and convenient using. Therefore the system has wide application prospects.