Crankshaft direction of rotation detecting apparatus

• US 5,079,945 A
• Filed: 01/23/1991
• Issued: 01/14/1992
• Est. Priority Date: 01/23/1991
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delco Electronics Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Jakupco, Richard J., Whitethorn, Michael L., Hansen, Mark C.
• Primary Examiner(s): MYRACLE, JERRY
• Application Number:
  US07/645,067
• Time in Patent Office: 356 Days
• Field of Search: 73/117.3, 73/116, 123/643, 123/612, 123/617, 123/621, 123/613
• US Class Current: 73/114.03
• CPC Class Codes: F02D 2250/06 Reverse rotation of engine
• CPC Class Codes: G01M 15/06 by monitoring positions of pistons or cranks
• CPC Class Codes: G01P 13/04 Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement

Abstract

Apparatus for detecting the direction of rotation of a crankshaft of an internal combustion engine. The crankshaft drives wheels associated with sensors for developing two pulse trains as the crankshaft rotates. One pulse train is a square wave having consecutively occurring high and low periods of equal angular duration. The other pulse train is a square wave having a plurality of spaced window pulses of unequal angular duration. The relative high and low logic states of the pulse trains at certain window locations has one relationship for forward movement of the crankshaft and a different relationship for reverse movement of the crankshaft. These relationships are detected. At one of the window locations, the relative high and low logic states of the pulse trains is the same for either forward or reverse rotation. Engine reversal at this location is detected by detecting the occurrence of two consecutively occurring relative logic states that are the same.

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.