Crankshaft direction of rotation detecting apparatus

Claim 2

Apparatus for providing electrical signals that are indicative of the direction of rotation of the crankshaft of an internal combustion engine, comprising in combination, an internal combustion engine having a crankshaft, means responsive to rotation of said crankshaft for developing first and second pulse trains, said first pulse train defined by a square wave having consecutively occurring high and low states, said second pulse train defined by a square wave having at least first and second spaced window pulses of different angular duration corresponding to predetermined angular positions of the crankshaft, each window pulse being defined by pulse edges and being in a low state for the duration of a window pulse, the phase relationship of said pulse trains being such that when said crankshaft is rotating in a first direction, a pulse edge of said first window pulse rises when said first pulse train is low and such that when said crankshaft is rotating in a second opposite direction a pulse edge of said first window pulse rises when said first pulse train is high, said phase relationship being such that the pulse edges of said second window pulse rise when said first pulse train is low when said crankshaft is rotating in either of said first or second directions, means responsive to said pulse trains for developing a signal of a predetermined logic state when a pulse edge of said first window pulse rises when said first pulse train is low and for changing the logic state of said signal when a pulse edge of said first window pulse rises when said first pulse train is high, and means responsive to said pulse trains for developing a signal of a predetermined logic state when there is two consecutive occurrences of a falling pulse edge of said second window pulse that occur respectively when said first pulse train is low.

Claim 3

The apparatus according to claim 1 where said first pulse train is developed continuously during one revolution of said crankshaft and where the consecutively occurring high and low states of said first pulse train are of equal durations that correspond to a predetermined amount of angular rotation of said crankshaft.

Claim 4

Apparatus for developing electrical signals that are indicative of the direction of rotation of the crankshaft of an internal combustion engine, comprising in combination, an internal combustion engine having a crankshaft, means responsive to rotation of said crankshaft for developing first and second pulse trains, said first pulse train defined by a square wave having consecutively occurring high and low states, said second pulse train defined by a square wave having at least first, second and third spaced window pulses of different angular duration that are each defined by pulse edges and each window pulse being in a low state for the duration of a window pulse, the phase relationship of said pulse trains being such that when said crankshaft is rotating in a first direction, a pulse edge of either of said first and third window pulses rises when said first pulse train is low and such that when said crankshaft is rotating in an opposite direction a pulse edge of either of said first and third window pulses rises when said first pulse train is high, said phase relationship being such that the pulse edges of said second window pulse rise when said first pulse train is low when said crankshaft is rotating in either of said first or second directions, means responsive to said pulse trains for developing a signal of predetermined logic state when a pulse edge of either of said first and third window pulses rises when said first pulse train is low and for changing the logic state of said signal when a pulse edge of either of said first and third window pulses rises when said first pulse train is high, and means responsive to said pulse trains for developing a signal of a predetermined logic state when there is two consecutive occurrences of a falling pulse edge of said second window pulse that respectively occur when said first pulse train is low.

Claim 5

Apparatus for developing electrical signals that are indicative of the direction of rotation of the crankshaft of an internal combustion engine, comprising in combination, an internal combustion engine having a crankshaft, means responsive to rotation of said crankshaft for developing first and second pulse trains, said first pulse train defined by a square wave having consecutively occurring high and low states, said second pulse train defined by a square wave having at least first, second and third spaced window pulses of different angular duration that are each defined by pulse edges and each window pulse being in a low state for the duration of a window pulse, the phase relationship of said pulse trains being such that when said crankshaft is rotating in a first direction, a pulse edge of either of said first and third window pulses rises when said first pulse train is low and such that when said crankshaft is rotating in an opposite direction a pulse edge of either of said first and third window pulses rises when said first pulse train is high, said phase relationship being such that the pulse edges of said second window pulse rise when said first pulse train is low when said crankshaft is rotating in either of said first or second directions, means responsive to said pulse trains for developing a signal of predetermined logic state when a pulse edge of either of said first and third window pulses rises when said first pulse train is low and for changing the logic state of said signal when a pulse edge of either of said first and third window pulses rises when said first pulse train is high, and means responsive to said pulse trains for developing a signal of a predetermined logic state when there is two consecutive occurrences of a falling pulse edge of said second window pulse that respectively occur when said first pulse train is low.

Claim 6

The apparatus according to claim 3 where said first pulse train is developed continuously during one revolution of said crankshaft and where the consecutively occurring high and low states of said first pulse train are of equal durations that correspond to a predetermined amount of angular rotation of said crankshaft.

Claim 7

The apparatus according to claim 3 were the durations of said consecutively occurring high and low states of said first pulse train each correspond to ten degrees of angular rotation of said crankshaft and wherein the durations of said first, second and third window pulses correspond respectively to ten, twenty and thirty angular degrees of rotation of said crankshaft.