Patent ID: 6041647
Filing Date: 2000-03-28
Classification: F01L,F02D,G01P

Abstract:
A crank angle detecting apparatus for an internal combustion engine having a plurality of cylinders, each cylinder retaining a piston, and a crank shaft operationally coupled to the pistons, wherein two rotations of the crankshaft correspond to one rotational cycle, such that each piston performs a stroke cycle during each rotational cycle, the stroke cycles being carried out in the cylinders with time phases in accordance with the rotational position of the crankshaft in one rotational cycle, the crank angle detecting apparatus comprising:a crank rotor fixed on the crankshaft to rotate with the crankshaft;a plurality of first-detected indicia provided on the periphery of the crank rotor at equal angular intervals of the crank rotor, wherein each first-detected indicium is like every other first-detected indicium in size and shape, the crank rotor having segments, wherein each adjacent pair of first-detected indicia defines a segment;a plurality of second-detected indicia provided on the periphery of each of the segments and within the angular intervals defined by adjacent pairs of the first-detected indicia, wherein each second-detected indicium is like every other second-detected indicium in size and shape and different from every first-detected indicium in size or axial location, and wherein the only indicia appearing in the angular interval between any two adjacent first-detected indicia are second-detected indicia, wherein a combination of the numbers of second-detected indicia located on any given plurality of adjacent segments is different from a combination of the numbers of second-detected indicia located on any other plurality of adjacent segments having the same number of segments as the given plurality;first detecting means, positioned to face rotational loci of both the first-detected indicia and the second-detected indicia, for detecting the first-detected and second-detected indicia that pass a position opposing the first detecting means in accordance with rotation of the crank rotor;first counting means for counting the number of the second-detected indicia in each segment based on detection of the first-detected and second-detected indicia by the first detecting means;signal generator for detecting a feature of the engine that indicates when the crankshaft makes one rotation; anddetermining means for determining the rotational position of the crankshaft in one rotational cycle when the first-detected indicia are detected by the first detecting means, based on a combination of the number of second-detected indicia located on at least two adjacent segments, which is based on a count value from the first counting means, and the indication of the signal generation means.