Method for setting a wheel torque in a vehicle

• US 8,688,348 B2
• Filed: 05/02/2011
• Issued: 04/01/2014
• Est. Priority Date: 06/01/2010
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Boeker, Ralph, Thomys, Adrian, Wagner, Oliver, Strauss, Tobias
• Primary Examiner(s): CAMBY, RICHARD M
• Application Number:
  US13/099,018
• Publication Number:
  US 20110295481A1
• Time in Patent Office: 1,065 Days
• Field of Search: 701/70, 701/71, 701/73, 701/74, 701/75, 701/79, 701/80, 701/82, 701/84, 701/87
• US Class Current: 701/87
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60T 8/17616 Microprocessor-based systems
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/263 Slip values between front and rear axle
• CPC Class Codes: B60W 2720/26 Wheel slip
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power

Abstract

In a method for setting a wheel torque in a vehicle, a setpoint value for a slip-adhesion coefficient gradient for one wheel of one vehicle axle is ascertained, and the wheel torque is set in such a way that the actual value of the gradient is approximated to the setpoint value.

Claims

1. A method for setting a wheel torque in a vehicle, comprising:

for at least one wheel on one vehicle axle, ascertaining a setpoint value for one of a) a slip-adhesion coefficient gradient, which gradient is a slope of a curve in which adhesion coefficient values are plotted over corresponding wheel slip values, or b) a variable correlated to the slip-adhesion coefficient gradient, and setting the wheel torque in such a way that an actual value of the slip-adhesion coefficient gradient is approximated to the setpoint value; and

ascertaining the slip-adhesion coefficient gradient from a wheel slip of one wheel and an adhesion coefficient as a quotient of longitudinal force to vertical force at the wheel.

2. The method according to claim 1, wherein, in the event that the actual value of the slip-adhesion coefficient gradient does not reach the setpoint value, a straight line of the gradient is shifted in parallel.

3. The method according to claim 1, wherein the setpoint value of the slip-adhesion coefficient gradient is kept constant.

4. The method according to claim 1, wherein the setpoint value of the slip-adhesion coefficient gradient is ascertained as a function of at least one current driving condition variable, including a vehicle velocity.

5. The method according to claim 1, wherein the actual value of the slip-adhesion coefficient gradient is calculated from the wheel slip and the adhesion coefficient of a front wheel and a rear wheel.

6. The method according to claim 5, wherein the adhesion coefficient at one wheel of one vehicle axle, including the rear wheel, is previously adopted.

7. The method according to claim 6, wherein the wheel slip and the adhesion coefficient at one wheel of the other vehicle axle, including the front wheel, are ascertained from measured values.

8. The method according to claim 1, wherein the wheel slip is calculated from measured wheel rotational speeds and a reference velocity.

9. The method according to claim 1, wherein at least one of (a) braking torques and (b) drive torques is set to achieve the setpoint value of the gradient.

10. A regulating or control device for setting a wheel torque in a vehicle, the device comprising an arrangement for performing the following:

for at least one wheel on one vehicle axle, ascertaining a setpoint value for one of a) a slip-adhesion coefficient gradient, which gradient is a slope of a curve in which adhesion coefficient values are plotted over corresponding wheel slip values, or b) a variable correlated to the slip-adhesion coefficient gradient, and setting the wheel torque in such a way that an actual value of the slip-adhesion coefficient gradient is approximated to the setpoint value; and

ascertaining the slip-adhesion coefficient gradient from a wheel slip of one wheel and an adhesion coefficient as a quotient of longitudinal force to vertical force at the wheel.