Method for regulating the speed of a motor vehicle

• US 20040041471A1
• Filed: 06/02/2003
• Published: 03/04/2004
• 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
• Granted Patent: US 6,932,441 B2
• Time in Patent Office: Days
• US Class Current: 303/191
• 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

A method for controlling the speed of a motor vehicle (10), in which an acceleration-demand signal (a_setpoint) is generated which represents a positive or negative setpoint acceleration of the vehicle, and either a control command (A) is output to the engine or a control command (B) is output to braking system (24, 26) of the vehicle as a function of this signal, wherein a signal (F) for preloading the braking system is output when the acceleration-demand signal (a_setpoint) falls below a threshold value which lies above a value at which the braking system (24, 26) is activated.

Claims

1. A method for controlling the speed of a motor vehicle (10), in which an acceleration-demand signal (a_setpoint) is generated which represents a positive or negative setpoint acceleration of the vehicle, and either a control command (A) is output to the engine or a control command (B) is output to braking system (24, 26) of the vehicle as a function of this signal, wherein a signal (F) for preloading the braking system (24, 26) is output when the acceleration-demand signal (a_setpoint) falls below a threshold value (TH) which lies above a value (a_min;

a_hys) at which the braking system (24, 26) is activated.

2. The method as recited in claim 1,

wherein a triggering threshold (a_min;

a_hys), at which the braking system (24, 26) is activated by output of the control command (B), is determined as a function of the vehicle deceleration that is able to be produced by the drag torque of the engine under the instantaneous operating conditions; and

the threshold value (TH), at which the signal (F) for preloading the braking system is output, lies by a specific amount Δ

a above this triggering threshold (a_min;

a_hys).

3. The method as recited in claim 2,

wherein the change rate of the acceleration-demand signal (a_setpoint) over time is restricted by a lower limit, and Δ

a is greater according to the amount than the product of this lower limit and the time which is necessary for preloading the braking system.

4. The method as recited in one of the preceding claims, wherein the signal (F) for preloading the braking system is reset when the braking system is actually activated.

5. The method as recited in claim 4,

wherein the signal (F) for preloading the braking system is set once more, or a signal (H) for retaining the preloading of the braking system is set when the braking system is deactivated.

6. The method as recited in claim 5,

wherein the renewedly set signal (F) for preloading the braking system or the signal (H) for retaining the preloading is reset when the acceleration-demand signal (a_setpoint) exceeds the threshold value (TH;

TH′

) again.

7. The method as recited in one of the preceding claims, wherein the signal (F) for preloading the braking system and/or the signal (H) for retaining the preloading is in each case reset at the latest after a time span (Δ

t) has elapsed which is fixed or is variable as a function of the condition.