A micro-processor based adaptive ignition control system

An adaptive ignition control system can adjust ignition angle automatically, so the power of the SI engine is improved while preventing it from knock. This paper describes an ignition control system, whose core is a micro-processor (80C552). The inputs include intake manifold pressure sensor, throttle position sensor, water temperature sensor, crankshaft position (speed) sensor, synchronization sensor and knock sensor. The software of the system includes main flow program and several interruption programs. The article describes how the knock signal acquisition, knock condition judgment, ignition-signal, etc. are controlled by the software. The peak-value of the knock signal is recorded in a circuit during one cycle, and accordingly this value of the knock is detected. A new two-parameter ignition angle adjusting method is used, which is according to the peak-value of knock signal during one cycle and the mean value of several cycle peak-values. This method effectively resolved the contrast of the high response and small cycle fluctuation of ignition angle control. The experiments on 368Q engine shows that the design of the system hard-and-software is feasible and the engine is prevented from knock effectively, the torque of the engine is improved