Delphi Technologies, Inc.

Keith Wayne Beyer

Eric Edward Krueger

Qingyuan Li

Raymond Kurt Schubert

Quan Zheng

Todd David Brown

Vincent E Marchese

Alan Rae Lustre

A traction control for a motor vehicle responds to detection of a rough road surface so as to shift control away from propulsion power reduction and toward brake control to an over-spinning driven wheel when the rough road surface is detected. This better adapts the traction control to a road surface that may have a high coefficient of friction but produces intermittent loss of traction due to wheel hop or normal force fluctuations due to the rough road surface. The lower power reduction is obtained by increasing a target brake pressure used to derive a brake pressure error signal from which from which a power reduction command is derived. A delta target brake pressure may also be increased to provide a higher target velocity for the driven wheel propulsion. For even higher levels of road roughness, the traction control reduces the gain of time derivative of a difference between a rotational wheel acceleration of the driven wheel and an undriven wheel rotational acceleration that contributes to the brake modulation, since wheel accelerations are of less use in controlling traction on such a road surface.

Vehicle traction control with rough road correction

A vehicle powertrain torque control provides an engine drag control mode of operation during periods of undesired engine drag induced wheel slip by modifying the torque of the vehicle engine in closed loop control to maintain a driven wheel speed at a predetermined target velocity lower than the vehicle speed by a target velocity difference providing as much engine braking as is consistent with a desired degree of lateral traction. The control derives a velocity error as the difference between the driven wheel speed and the target velocity and derives and delivers to the powertrain a torque command for reducing the velocity error. The torque control determines the engine drag control mode in response to the wheel speed sensors, preferably causing entry of the engine drag control mode when the driven wheel speed that is closest to the vehicle speed falls below the target velocity while powertrain delivered torque and throttle position are below predetermined values indicative of deceleration. The target velocity difference is preferably determined as a weighted difference between vehicle speed and vehicle turn curvature, the difference being reduced by the latter for quicker response in vehicle turns.

Vehicle engine torque control with engine drag control mode

A method and apparatus are provided for estimating brake pressure in a disk brake caliper, on the basis of a simplified mathematical model. The simplified model is limited to operating conditions in which the caliper piston is holding the brake pads in contact with the rotor, wherein higher order terms and certain fluid dependent terms of the model can be eliminated, thereby simplifying the model to the point that it can be readily used in an effective and efficient manner for estimating fluid pressure in the cylinder of the caliper. The displacement of the piston is estimated while the piston is holding the brake pad in contact with the rotor, as a function of an exchange of fluid between the pressure source and the cylinder. The brake pressure in the cylinder is determined as a function of the displacement of the piston while the piston is holding the brake pad in contact with the rotor. The exchange of fluid between the cylinder and pressure source is estimated as a function of a difference in pressure between the cylinder and the source.

Model based brake pressure estimation

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Novi, MI, United States of America

Keith Wayne Beyer