Gm Global Technolgoy Operations, Inc.

Susan Jean Lane

Lisa Marie Unuvar

Vivek Mehta

Daniel Alexander Crawford

David L Ehle

Daniel J Richardson

Gregory J Johnson

Timothy Lee Budzier

Mechanical lash in a cruise control system including a cruise control actuator linked to an engine intake air valve through a cruise cable assembly is automatically measured and stored for use in cruise control operations. The cruise control actuator is driven from a base position along a position schedule while an engine parameter responsive to change in intake air valve position is monitored for any significant parameter change indicating movement of the intake air valve in response to the actuator movement. The amount of actuator movement required before any significant change occurs in the engine parameter is stored as representing the mechanical lash. Cruise control commands are augmented by the learned mechanical lash before being applied to the cruise control actuator.

Automatic speed control with lash compensation

A vehicle speed control system provides adaptive compensation for compliance in a linking mechanism between a throttle control member and a throttle which creates hysteresis in throttle movement. The system has a vehicle speed sensor, an actuator having an output linked to the throttle control member, an actuator position signal generator and a control responsive to the vehicle speed sensor and the actuator position signal generator for positioning the actuator in closed loop control with a major loop in response to vehicle speed and a minor loop in response to actuator position. The control repeatedly determines when vehicle speed is not within a predetermined range and responds (1) deriving a desired actuator position signal, a present actuator position signal and a position error signal from the difference therebetween, (2) deriving an output position signal from the desired actuator position signal when the position error signal is not zero, (3) modifying the output position signal by a compliance compensation value for actuator movement in a first direction, and (4) activating the actuator to a position corresponding to the output position signal. The control further accumulates the second and subsequent position error signals for actuator movement in the first direction as an accumulated difference value and, when actuator movement is initiated in a second direction, updates the compliance compensation value as a predetermined percentage of the sum of the compliance compensation value and the accumulated difference value.

Vehicle speed control with adaptive compliance compensation

A driver override of a cruise control system is detected and employed to suitably alter the powertrain controls. A driver override of the cruise control system is detected by a lack of correspondence between the engine throttle position and the cruise control servo position, taking into account any hysteresis and lash which may occur in the linkage coupling the servo to the throttle. The lash is determined by storing the measured servo position whenever the measured throttle position is equal to a predefined value, and the controller responds during a detected driver override by instituting normal or noncruise related control parameters. This control permits the cruise control parameters to yield smooth control without unnecessary shifting while retaining a more responsive control during driver override conditions.

Driver override control logic for a motor vehicle powertrain control

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Clarkston, MI, United States of America

Susan Jean Lane