The Development Of Electronic Controlling System For A Single Fuel Gas Engine Based On Motorola MC9S12 Chip

Natural Gas is more and more concerned because of its availability, low pollution and economy. Therefore the engine fueled by natural gas has become research hotspot. With the widespread of natural gas automobiles, it is important to further develop high performance electronic controlling system for them.A gas injection electronic-controlling system has been developed based on NQ150N engine in this paper, in which one natural gas injector is amounted in intake manifold near every intake valve and multi-point sequential injection and high energy sequential ignition are carried out by adding a camshaft position sensor. Every sensor is selected reasonably. The chip is MC9S12DG128B of Motorola HCS12 series SCM and the program is written in C language. Finally an electronic controlling system experiment platform is established for researching and developing high efficiency, low pollution and electronic controlling injection single fuel charged inter-cooled CNG engine.Electronic controlling software is developed based on the analysis of performance of multipoint sequential injection system and high energy direct ignition system, in which anti-interference measure is applied to further improve system stability and reliability. Backstage monitor software is developed for the real-time calibration of MAP and the monitor of engine working state. This software can show engine working state and edit the controlling specifics real-time in the way of serial communication.The marching calibration test of electronic controlling system and engine is carried out. The test results show that, this CNG engine electronic controlling system is designed reasonably, and can accurately control the multipoint injection time, injection quantity and high energy ignition; this system is stable and its performance is reliable, which makes the performance of this CNG engine such as power and torque satisfy the requests of the original engine. On the base of this test, some engine performance specifics such as ignition advance angle, injection timing and equivalent air-fuel ratio were studied in test, which is of guiding meaning for subsequent specifics optimization.