Test Rig for Measurement of Spark Advance Angle and Ignition System Using AT89C51 Microcontroller

An electronic ignition control system for internal combustion engine, notably for motor vehicles, which comprises a rotary member revolving at engine speed and provided with two reference marks Which the position correspond to the maximum ignition advance angle and to the minimum ignition advance angle, respectively , said reference marks defining at least one area on said rotary member, a sensor disposed in close vicinity of said rotary member so as to detect the moments of passage of said references marks and at least one up and down counter for counting pulse, said rotary member further comprising a third references marks separate from the first two reference marks aforesaid so as to define two successive areas scanned in succession by said sensor, while a first up and down counter positively counts the pulse from a first area and negatively counts, during passage of second area the pulse from second clock system adapted to emit pluses at a frequency programmable according to the desired ignition advance law, the resetting of said up and down counter being utilized for producing ignition spark. Finally up and down counter calculates the final value of the advance angle. After calculating the final value of advance angle signal send to the ignition box to ignition coil, and ignition coil operate the spark as per advance angle.