Gm Global Technolgoy Operations, Inc.

David Alan Thatcher

Kevin Gerard Leppek

Allen John Walenty

Alexander Kade

Timothy John Hartrey

Gordon L Tierney

Ananth Krishnan

Alfred Russell Robertson

John Andrew Weber

A transmission control system for a vehicle includes a first module that generates a first modified signal based on a first position of a driver input device and a second module that receives the first modified signal from the first module. The second module generates a second modified signal based on a second position of the driver input device and regulates operation of a transmission of the vehicle based on the first and second modified signals.

System architecture optimization for electronic transmission range selection

An improved ABS control method incorporates entry criteria for initiating ABS control based on brake pedal position and rate of depression, adaptively adjusted by a reference pedal position corresponding to a predefined vehicle deceleration. A periodically-updated characterization of the relationship between brake pedal position and vehicle deceleration is used to establish the reference brake pedal position, and when insipient wheel lock is detected, the initiation of ABS control is delayed by an entry delay period that decreases with increasing rate of pedal depression and with the degree to which the pedal position exceeds the reference pedal position. In this way, the entry conditions are predicated primarily on the manner of brake pedal depression, with adaptive adjustment for variations in braking effectiveness.

Anti-lock brake control method having adaptive entry criteria

An improved anti-lock control method for a vehicle brake system identifies various factors that degrade the effectiveness of the brake system and adaptively adjusts a brake apply rate during anti-lock brake control to compensate for the identified degradation so that the optimal tractive force during anti-lock brake control is more nearly realized. The identified factors include fading due to brake heating, hydraulic leakage, mis-adjusted and non-releasing rear brakes, brake wear and excessive vehicle weight.

Adaptive compensation method for an anti-lock brake control

A method and apparatus for operating a vehicle anti-lock braking system includes a brake pedal and a brake modulator that reduces braking pressure by an initial pressure reduction after detecting insipient wheel lock. Vehicle deceleration is measured as a function of brake pedal position. A first table is updated with the vehicle deceleration and the brake pedal position. A coefficient of friction of a road surface is estimated based on the first table. A slip target for at least one wheel is estimated and is based on an estimated maximum slip of the at least one wheel before losing traction minus an estimated potential for vehicle rollover. A deceleration target for at least one wheel is estimated and is based on an estimated maximum deceleration of the at least one wheel before losing traction minus the estimated potential for vehicle rollover.

Anti-lock braking system controller for adjusting slip thresholds on inclines

A vehicle anti-lock braking system includes a brake pedal and a brake modulator. The brake system reduces braking pressure by an initial pressure reduction after detecting insipient wheel lock. Vehicle deceleration is measured as a function of brake pedal position. A first table is updated with the vehicle deceleration and the brake pedal position. A coefficient of friction of a road surface is estimated based on the first table. Wheel slip and deceleration target thresholds are determined based on the coefficient of friction. The wheel slip and deceleration target thresholds are used to populate a command table for the anti-lock braking system. Brake heat, brake torque, vehicle weight and grade are estimated. Release and apply pressures are calculated from an adjusted coefficient of friction, a coefficient of friction and the grade.

Method for determining optimal ABS slip and deceleration thresholds

An improved anti-lock brake control method in which the brake pressure reduction initiated upon detection of insipient wheel lock is adaptively determined based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration. The brake torque and vehicle weight are estimated based on the characterization data, corrected for variation in brake heating, and used to compute the surface coefficient of friction, which in turn, is used to schedule the initial anti-lock brake pressure reduction for optimal braking system performance.

Anti-lock brake control method having adaptive initial brake pressure reduction

A brake system control method for use in a vehicle in which wheel speed normalization factors are iteratively updated, comprising the steps of: monitoring a plurality of wheel speed signals from a plurality of wheel speed sensors; determining for each wheel a wheel acceleration responsive to the wheel speed signal; determining an acceleration dead band for each wheel, wherein the acceleration dead band is proportional to a measure of vehicle acceleration; comparing the wheel acceleration to the dead band; and if the magnitude of the wheel acceleration is greater than the magnitude of the dead band, inhibiting update of the normalization factors.

Brake system control in which update of wheel speed normalization factors is selectively inhibited

An improved method of diagnosing conditions of a vehicle braking system that degrade the braking effectiveness informs the driver of the condition so that repair or adjustment can be timely made. The relationship between brake pedal position and vehicle deceleration is determined during a calibration interval to construct a calibration table of brake effectiveness, and then periodically over the life of the braking system to develop a current brake effectiveness table. Braking system abnormalities that impair the braking effectiveness are diagnosed by analyzing the table values.

Method of diagnosing a vehicle brake system using brake pedal position and vehicle deceleration

A method of brake control, comprising the steps of: determining a deceleration of a vehicle; measuring a first wheel rotational velocity of a front wheel of the vehicle; measuring a second wheel rotational velocity of a rear wheel of the vehicle; determining a front wheel normalization value responsive to the deceleration and a front tire deformation constant; determining a rear wheel normalization value responsive to the deceleration and a rear tire deformation constant; determining a front normalized wheel rotational velocity responsive to the front wheel normalization value and the first wheel rotational velocity, wherein the front normalized wheel rotational velocity is responsive to a front tire deformation that occurs during a braking maneuver of the vehicle; determining a rear normalized wheel rotational velocity responsive to the rear wheel normalization value and the second wheel rotational velocity, wherein the rear normalized wheel rotational velocity is responsive to a rear tire deformation that occurs during a braking maneuver of the vehicle; subtracting the front normalized wheel rotational velocity from the rear normalized wheel rotational velocity to determine a difference; and adjusting front to rear brake proportioning responsive to the difference, wherein front to rear brake proportioning is responsive to tire deformation that occurs during a braking maneuver.

Method for proportionally controlling the brakes of a vehicle based on

A traction control system limits the spin of a vehicle driven wheel at a spin limit value that is a function of the vehicle turn rate and that is decreased as a function of the vehicle turn rate of change.

Vehicle traction control system

The application of brake pressure to limit the spin of a driven wheel in a traction control system is made adaptive to the torque demand on the engine. This is accomplished by increasing the brake pressure when an excessive spin condition is sensed at a rate that is proportional to a parameter related to engine torque. The ramp is then terminated when the wheel parameters attain certain predetermined conditions. The brake pressure ramp is terminated when the wheel jerk is negative while at the same time the wheel deceleration is below a predetermined value. After the ramp is terminated, the brake pressure of the spinning wheel is controlled based on wheel parameters such as wheel spin ratio or the difference between the speed of the spinning wheel and vehicle speed.

A traction control system for limiting the slip of a driven wheel determines an excessive spinning condition of the wheel in response to an excess driving torque applied from the vehicle engine. If the vehicle speed is less than a predetermined value, a braking force is applied to the wheel that is a predetermined function of the spin ratio of the wheel and when the vehicle speed is greater than the predetermined value, a braking force is applied to the wheel that is a predetermined function of the difference between the driven wheel speed and the vehicle speed.

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Troy, MI, United States of America

David Alan Thatcher