JPH05288112

PURPOSE:To provide a crank angle position detection apparatus for internal combustion engine which enables the cylinder discrimination at a time earlier than a 720 deg. rotation of a crank shaft and the detection of a crank angle position thereat, without using three or more pulse signal outputting devices. CONSTITUTION:This crank angle position detection apparatus comprises a number-of-rotation sensor 6 for outputting a number-of-rotation signal for each rotation of a crank shaft through a specified angle, and, a cylinder discrimination sensor 10 for outputting one cylinder discrimination signal for each one full rotation of a cam shaft. When the interval between input number-of-rotation signals from a number-of-rotation sensor 6 exceeds a specified value, CPU 13 uses a succeeding out of those signals as a reference position signal. The CPU 13 counts the number-of-rotation signals from the number-of-rotation sensor 6 and, when the counted value reaches a specified value set beforehand, makes its decision on the presence or absence of a cylinder discrimination signal outputted from the cylinder discrimination sensor 10. The CPU 13 detects a particular cylinder crank angle position of the internal combustion engine in accordance with the result of that decision.