Method for regulating the speed of a motor vehicle

• US 6,932,441 B2
• Filed: 02/16/2002
• Issued: 08/23/2005
• Est. Priority Date: 04/12/2001
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Irion, Albrecht, Hellmann, Manfred, Lauxmann, Ralph
• Primary Examiner(s): WILLIAMS, THOMAS J
• Application Number:
  US10/297,952
• Publication Number:
  US 20040041471A1
• Time in Patent Office: 1,284 Days
• Field of Search: 188/181.A, 303/191, 303/193, 303/177, 303/184, 303/125, 701/70, 701/93, 701/96
• US Class Current: 303/177
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60T 2201/12 Pre-actuation of braking systems without significant braking effect; Optimizing brake performance by reduction of play between brake pads and brake disc
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle

Abstract

In a method for controlling the speed of a motor vehicle, an acceleration-demand signal is generated which represents a positive or negative setpoint acceleration of the vehicle, and either a control command is output to the engine or a control command is output to braking system of the vehicle as a function of this signal, wherein a signal for preloading the braking system is output when the acceleration-demand signal falls below a threshold value which lies above a value at which the braking system is activated.

Claims

1. A method for controlling a speed of a vehicle, comprising:

generating an acceleration-demand signal which represents one of a positive setpoint acceleration of the vehicle and a negative setpoint acceleration of the vehicle;

outputting one of a first control command to an engine of the vehicle and a second control command to a braking system of the vehicle as a function of the acceleration-demand signal;

outputting a signal for preloading the braking system when the acceleration-demand signal falls below a threshold value which is above a value at which the braking system is activated;

determining a triggering threshold as a function of a vehicle deceleration; and

restricting a change rate of the acceleration-demand signal over time by a lower limit.

2. The method as recited in claim 1, wherein:

the triggering threshold is that at which the braking system is activated by the output of the second control command, and the vehicle deceleration is that which is produceable by a drag torque of the engine under instantaneous operating conditions; and

the threshold value, at which the signal for preloading the braking system is output, is above the triggering threshold by a specific amount.

3. The method as recited in claim 1, further comprising:

resetting the signal for preloading the braking system when the braking system is actually activated.

4. The method as recited in claim 3, further comprising:

when the braking system is deactivated, one of renewedly setting the signal for preloading the braking system, and setting a signal for retaining the preloading of the braking system.

5. The method as recited in claim 4, further comprising:

resetting one of the renewedly set signal for preloading the braking system and the signal for retaining the preloading when the acceleration-demand signal exceeds the threshold value.

6. A method for controlling a speed of a vehicle, comprising:

generating an acceleration-demand signal which represents one of a positive setpoint acceleration of the vehicle and a negative setpoint acceleration of the vehicle;

outputting one of a first control command to an engine of the vehicle and a second control command to a braking system of the vehicle as a function of the acceleration-demand signal;

outputting a signal for preloading the braking system when the acceleration-demand signal falls below a threshold value which is above a value at which the braking system is activated; and

determining a triggering threshold, at which the braking system is activated by the output of the second control command, as a function of a vehicle deceleration that is produceable by a drag torque of the engine under instantaneous operating conditions, wherein the threshold value, at which the signal for preloading the braking system is output, is above the triggering threshold by a specific amount;

restricting a change rate of the acceleration-demand signal over time by a lower limit, wherein the specific amount is greater by an amount than a product of the lower limit and a time necessary for preloading the braking system.

7. The method as recited in claims 6, further comprising resetting the signal for preloading the braking system when the braking system is actually activated.

8. The method as recited in claim 7, further comprising:

one of, when the braking system is deactivated, renewedly setting the signal for preloading the braking system, and setting a signal for retaining the preloading of the braking system.

9. The method as recited in claim 8, further comprising:

resetting one of the renewedly set signal for preloading the braking system and the signal for retaining the preloading when the acceleration-demand signal exceeds the threshold value.

10. The method as recited in claim 8, further comprising:

resetting at least one of the signal for preloading the braking system and the signal for retaining the preloading after a time span has elapsed which is one of fixed and variable as a function of the instantaneous operating conditions.

11. A method for controlling a speed of a vehicle, comprising:

generating an acceleration-demand signal which represents one of a positive setpoint acceleration of the vehicle and a negative setpoint acceleration of the vehicle;

outputting one of a first control command to an engine of the vehicle and a second control command to a braking system of the vehicle as a function of the acceleration-demand signal;

outputting a signal for preloading the braking system when the acceleration-demand signal falls below a threshold value which is above a value at which the braking system is activated;

resetting the signal for reloading the braking system when the braking system is actually activated;

when the braking system is deactivated, one of renewedly setting the signal for preloading the braking system, and setting a signal for retaining the preloading of the braking system; and

resetting at least one of the signal for preloading the braking system and the signal for retaining the preloading after a time span has elapsed which is one of fixed and variable as a function of the instantaneous operating conditions.

12. The method as recited in claim 11, further comprising:

determining a triggering threshold as a function of a vehicle deceleration; and

restricting a change rate of the acceleration-demand signal over time by a lower limit.

13. The method as recited in claim 12, wherein:

the triggering threshold is that at which the braking system is activated by the output of the second control command, and the vehicle deceleration is that which is produceable by a drag torque of the engine under instantaneous operating conditions; and

the threshold value, at which the signal for preloading the braking system is output, is above the triggering threshold by a specific amount.

14. The method as recited in claim 13, wherein the specific amount is greater by an amount than a product of the lower limit and a time necessary for preloading the braking system.