Cylinder Pressure Signal Detection System

Following with the sustainable growth of the automobile, the need of improvementwith car engine performance is increasingly urgent. The pressure in a cylinder is importantreference agent to the diagnosis of engine faults. The testing of cylinder pressure is veryimportant in study of combustion process and troubleshooting of gasoline engines. So, it isnecessary to study on testing equipment of Car cylinder pressure.In view of the development process and current situation of cylinder pressure testingand analysis equipment, this thesis studied a new style low power consumption handyequipment of testing car cylinder pressure which is based on the method of testing the carignition current, and it could send the real-time measurement data of car cylinder pressureto upper system and backup in PC computer through wireless transmission way. Firstly,the thesis makes comparison and analysis about the measuring method and sensor, andthen chooses the Rogowski coil based on the printed circuit board as the sensor. This lowpower consumption handy equipment is making up of wireless transmission and receivingmodule, lower computer data acquisition system and upper PC data receiving system.Lower PC mainly completes the measurement and processing data of cylinder pressureand sends it to the upper PC through wireless data transmission module. The uppermachine which is the data receiver mainly completes the cylinder pressure data receivingby the communication between USB device and PC computer and then backup the data inthe PC computer.This design is also set up the anti-interference measures in detail of the cylinderpressure testing system according to the working environment of the automotive engines.The anti-interference measures is taken step in hardware and software accordingly. I takestep by using metal shell for the electromagnetic shielding on the hardware side,"WATCHDOG" in the single chip program preventing from work abnormality caused byprogram fleet and redundant technology to resume working correctly on the software side.In addition, I also utilize CRC checking to ensure the system accuracy and reliability ofdata transmissions.