Method and control system for setting a presettable vehicle desired speed

• US 6,317,678 B1
• Filed: 05/26/2000
• Issued: 11/13/2001
• Est. Priority Date: 05/31/1999
• Status: Expired due to Term

• Current Assignee: 21ST CENTURY GARAGE LLC
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Linden, Thomas
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): TO, TUAN C
• Application Number:
  US09/578,855
• Time in Patent Office: 536 Days
• Field of Search: 701/94, 701/93, 701/110, 180/179, 180/170, 123/350
• US Class Current: 701/94
• 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: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: G05B 5/01 electric

Abstract

In a method for setting a presettable vehicle desired speed, control signals for manipulation of the engine and/or the transmission of the motor vehicle are produced in a cruise control system, taking account of vehicle state variables and operating variables. In order to avoid overshoots occurring as the desired speed is approached, a substitute speed is preset which differs from the desired speed and is formed by applying an offset to the desired speed. The substitute speed is above or below the desired speed depending on the actual vehicle speed. When the actual vehicle speed approaches the desired speed, the substitute speed is used for cruise control.

Claims

1. Method for setting a presettable vehicle desired speed in a vehicle having a cruise control system in which ouptput control signals are generated by a regulator for manipulation of a vehicle engine or the transmission, taking account of vehicle state variables and operating variables, said method comprising:

presetting a substitute speed which differs from a desired vehicle speed, and is formed by applying an offset to the desired speed, the substitute speed being greater or less than the desired speed depending on actual vehicle speed;

using the substitute speed for cruise control regulation of vehicle operation; and

as the actual vehicle speed approaches the desired speed, reducing the offset to zero when

the vehicle speed carries out a transient process about the substitute speed; and

one transient cycle of vehicle speed has occurred.

2. The method as claimed in claim 1, wherein as a condition for reducing the offset to zero, a determination is made whether the actual speed change is zero.

3. The method according to claim 1, wherein as a condition for reducing the offset to zero, a determination is made whether a regulator output of the cruise control system is zero.

4. The method according to claim 1, wherein the offset is formed as a function of an actual vehicle speed change.

5. The method according to claim 1, wherein the offset is formed as a function of actual transmission gear of the vehicle transmission.

6. The method according to claim 1, wherein the offset is less than or equal to the difference between the actual vehicle speed at the time of application of the substitute speed, and the desired speed.

7. The method according to claim 1, wherein the offset is limited to a maximum value.

8. The method according to claim 1, wherein as a condition for implementing the substitute speed for cruise control, it is determined whether the speed change i n a direction of the desired speed exceeds a speed change threshold value.

9. The method according to claim 1, wherein as a condition for implementing the substitute speed for cruise control, it is determined whether the actual vehicle speed is initially outside a speed interval between the desired speed and a speed threshold value.

10. The method according to claim 1, wherein as a condition for implementing the substitute speed for cruise control, it is determined whether the actual vehicle speed is within the speed interval between the desired speed and the speed threshold value.

11. A cruise control system for setting a presettable vehicle desired speed, in which control signals for manipulation of an engine or transmission of the motor vehicle can be produced taking account of vehicle state variables and operating variables, and to which a substitute speed which differs from the desired speed can be supplied as the nominal signal, said substitute speed being determined by applying an offset to the desired speed, with the substitute speed being above the desired speed if the actual vehicle speed is also above the desired speed, and below the desired speed if the actual vehicle speed is also below the desired speed, wherein as the actual vehicle speed approaches the desired speed, the offset is reduced to zero when

the vehicle speed carries out a transient process about the substitute speed;

and

one transient cycle of vehicle speed has occurred.

12. A method of operating a vehicle having a cruise control function for achieving a desired vehicle speed, comprising:

forming a substitute speed by addition of a speed offset to the desired vehicle speed, said substitute speed having a value that is between the desired vehicle speed and an actual vehicle speed;

using said substitute speed as a target speed for cruise control until actual vehicle speed undergoes a single transient change about said substitute speed; and

using said desired vehicle speed as a target speed for cruise control, thereafter.

13. Method for operating a vehicle cruise control system in which output control signals are generated by a regulator for manipulation of a vehicle engine or transmission, based on a presettable vehicle desired speed, said method comprising:

presetting a substitute speed which differs from a desired vehicle speed, and is formed by applying an offset to the desired speed, the substitute speed being greater or less than the desired speed depending on actual vehicle speed;

using the substitute speed for cruise control regulation of vehicle operation;

as the actual vehicle speed approaches the desired speed, reducing the offset to zero when;

the vehicle speed carries out a transient process about the substitute speed; and

one transient cycle of vehicle speed has occurred.

14. Method for setting a presettable vehicle desired speed in a vehicle have a cruise control in which output control signals are generated by a regulator for manipulation of a vehicle engine or transmission taking account of vehicle state variables and operating variables, said method comprising:

presetting a substitute speed which differs from a desired vehicle speed, and is formed by applying an offset to the desired speed, the substitute speed being greater or less than the desired speed depending on actual vehicle speed;

using the substitute speed for cruise control regulation of vehicle operation when actual vehicle speed differs from the desired vehicle speed by more than a predetermined interval; and

reducing the offset to zero when,

the actual vehicle speed approaches to within the predetermined interval from the desired speed;

the vehicle speed commences a transient oscillation about the substitute speed; and

one transient cycle of vehicle speed has occurred.