Signal Acquisition Of Electronic Controlled Engine And Design Of Fault Simulation System

With the development of modern automobile industry and electronic information technology, the degree of automotive electronic comes higher and higher, and the performance of cars has been greatly optimized. Electronic control and sensor technology make a contribution to the engine in the precision and stability of controlling and in fuel consumption. The engine collects accurate data through the coolant temperature sensor, ignition coil voltage sensor, crankshaft and camshaft position sensor, and pressure sensors. Then the actuator is driven after the controller is processed. This is a very complex integrated system of machine, electricity, and oil. In the case of continuous operation of high load, the fault of the sensor itself is more likely to occur than the driving computer. In the teaching of electric control engine, in addition that some physical and mechanical phenomena should be qualitatively observed, the output signal of the sensor in the running process should also be measured accurately by using the engine signal acquisition and fault simulation device.In this paper, based on the electronic controlled engine test bench in Chengxian College of Southeast University, a set of signal acquisition and sensor fault simulation system is developed according to the characteristics of the common sensor output signal. The system slave computer hardware uses the micro controller and the CPLD combination structure. The main circuit modules include analog signal conditioning, ADC, CPLD extension, equal precision frequency measurement, local data storage, EEPROM parameter storage, TFT screen display, matrix keyboard, etc. Using the micro controller MSP430F169 as the main controller, the sensors’ analog signals of temperature, pressure and coil voltage are collected and processed through the signal conditioning and ADC circuit by MSP430F169. The digital signal outputted by the sensor such as speed and crankshaft position is measured by CPLD chip EPM570. In the IAR5.3 and Quartus 9.0 development environment, C and VHDL language are used to develop the communication protocol of MSP430F169 and EPM570. The master controller sends a fault code to the CPLD. Then the CPLD uses its IO ports to control the connect or disconnect of the relay. Thus the simulation of sensor fault is achieved eventually.The monitoring software of host computer is exploited by using Delphi and Access database. It mainly consists of sensor information management, data collection, data query and display, the next bit machine calibration and other functional modules. Delphi is a visual development environment, which is very suitable for serial communication. Access is a relational database management system developed by Microsoft. It is very convenient to install. The slave computer collects data through the serial port to send the data to the host computer with a view to save, display and processing. Using the monitoring software and other measuring instruments, the calibration and compensation of the measuring accuracy of the lower computer can be realized.Test results show that the system can accurately measure the output signal of a variety of sensors and can simulate circuit fault of different sensors, which provide a kind of experimental devices for the teaching of the electronic controlled engine.