Electronic position and speed sensing device

A method of determining the direction of rotation of an engine wherein the passage of two position indicators located on an encoder wheel is sensed by a sensor means comprising comparing data derived from an electrical signal corresponding to passage of said position indicators past said sensor means under engine operating conditions with data corresponding to an electrical signal for a first direction of rotation and indicating rotation direction in an opposite sense to said first direction where said derived data varies by a greater than acceptable margin from data corresponding to said first direction of rotation.

A method of determining the direction of rotation of an engine wherein the passage of two position indicators located on an encoder wheel is sensed by a sensor means to provide an electrical signal corresponding to the passage of each respective position indicator, each signal having a leading edge and a trailing edge, the timing, t3, between passage of trailing edges of the electrical signals corresponding to each position indicator being multiplied by a factor of n and compared with the timing, t4, of passage between the trailing edge of a first position indicator and the leading edge of the first position indicator on a subsequent revolution of the encoder wheel such that, when nt3<t4, rotation is determined as being in a correct direction and when nt3>t4, rotation is in an incorrect direction.

An electronic control unit (ECU) for an internal combustion engine having an engine position and speed sensor system comprising:

• a circular element rotatably driven about an axis thereof at a speed directly related to engine speed, said circular element having thereon two peripherally spaced position indicators spaced apart by a first angular extent and at least one of said position indicators spaced apart from top dead centre by a second angular extent wherein said second angular extent is a multiple of said first angular extent;
• sensor means fixed in position with respect to said circular element, the sensor means for detecting the passage therepast of each of said position indicators as the circular element rotates and for producing in response to said passage respective electrical signals;
• wherein said ECU is adapted to receive said electrical signals from said engine position and speed sensor system and said ECU further comprising a shift function for use in producing information as to the angular position or angular velocity of the circular element from said electrical signals received by the ECU.

An electronic control unit (ECU) for an engine comprising an encoder wheel with two position indicators and a sensor for sensing passage of position indicators therepast wherein said ECU is adapted to receive electrical signals from said sensor and includes a comparator for comparing data derived from an electrical signal corresponding to passage of said position indicators past said sensor under engine operating conditions with data corresponding to an electrical signal for a first direction of rotation, the ECU being adapted to indicate rotation direction in an opposite sense to said first direction where said derived data varies by a greater than acceptable margin from data corresponding to said first direction of rotation.

An electronic control unit (ECU) for an engine comprising an encoder wheel with two position indicators and a sensor for sensing passage of position wherein said ECU is adapted to receive an electric signal from said sensor, corresponding to the passage of each respective position indicator therepast, each signal having a leading edge and a trailing edge, the ECU comprising a multiplier for multiplying the time t3, between passage of trailing edges of the electrical signals corresponding to each position indicator by a factor of n;

• and
• a comparator for comparing the timing, t4, of passage between the trailing edge of a first position indicator and the leading edge of the first position indicator on a subsequent revolution of the encoder wheel with nt3 wherein the ECU determines that rotation is in a correct direction when nt3<t4 and the ECU determines that rotation is in an incorrect direction and when nt3>t4.