Method of detecting the rotational direction of an output shaft during starting

A method for detecting, via a shifting element conducive to positive engagement, a start of motion of a motor vehicle that is initially in a decoupled state and in a rest position, the method comprising the steps of;

• detecting a rotational direction of an output shaft of an automated transmission when the motor vehicle starts to roll,
• outputting a signal, from a single rotational speed sensor, to an electronic transmission control produced by a transmitter during rotation of the output shaft and representation an output rotational speed (n_AB),
• detecting an actual drive state,
• determining a gradient value representing a time-related gradient of the output rotational speed (n_AB) of a determined transmission output rotational speed (n_AB),
• comparing the gradient value with appertaining values (n_VE, n_VH, n_VHL, n_RHL) characteristic for a drive state when the motor vehicle starts to roll in one of forward travel (D) and reverse travel (R), with each value (n_VE, n_VH, n_VHL, n_RH, n_RHL) being associated with one of the following drive states
• “forward travel on flat terrain”;
• “forward travel downhill”;
• “forward travel uphill”;
• “forward travel uphill with reverse rolling”;
• “reverse travel in flat terrain”;
• “reverse travel downhill”;
• “reverse travel uphill”;
• and
• “reverse travel uphill with reverse rolling”,
• the drive states being stored respectively both with and without load conditions,
• calculating a synchronization point at which engagement of the shifting element conducive to positive engagement is carried out according to the detected drive state,
• using a gradient of the output rotational speed (n_AB) as criterion for differentiating between the drive states, and
• detecting a start in a forward travel uphill with a reverse rolling downhill as the drive state when the output rotational speed (n_AB) for a short time increases with low gradient and then again becomes zero in order to accelerate again after the standstill.

A method for detecting, via a shifting element conducive to positive engagement, a start of motion of a motor vehicle that is initially in a decoupled state and in a rest position, the method comprising the steps of;

• detecting a rotational direction of an output shaft of an automated transmission when the motor vehicle starts to roll,
• outputting a signal, from a single rotational speed sensor, to an electronic transmission control produced by a transmitter during rotation of the output shaft and representation an output rotational speed (n_AB),
• detecting an actual drive state,
• determining a gradient value representing a time-related gradient of the output rotational speed (n_AB) of a determined transmission output rotational speed (n_AB),
• comparing the gradient value with appertaining values (n_VE, n_VH, n_VHL, n_RHL) characteristic for a drive state when the motor vehicle starts to roll in one of forward travel (D) and reverse travel (R), with each value (n_VE, n_VH, n_VHL, n_RH, n_RHL) being associated with one of the following drive states
• “forward travel on flat terrain”;
• “forward travel downhill”;
• “forward travel uphill”;
• “forward travel uphill with reverse rolling”;
• “reverse travel in flat terrain”;
• “reverse travel downhill”;
• “reverse travel uphill”;
• and
• “reverse travel uphill with reverse rolling”;
• the drive states being stored respectively both with and without load conditions,
• calculating a synchronization point at which engagement of the shifting element conducive to positive engagement is carried out according to the detected drive state,
• using, as criterion for differentiating between the drive states, a reaction time (Δt) which extends from a starting signal up to detection of an output rotational speed (n_AB) higher then zero, and
• shortening a calculated reaction time (Δt) up to the detection of an output rotational speed (n_AB) when a load requirement exists after a starting wish and prior to detection of an output rotational speed.