Vehicle cruise control system and method having improved target speed resolution feature

• US 5,957,992 A
• Filed: 09/11/1996
• Issued: 09/28/1999
• Est. Priority Date: 09/11/1995
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Kiyono, Masashi
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US08/712,467
• Time in Patent Office: 1,112 Days
• Field of Search: 701/70, 701/93, 701/103, 701/110, 123/350, 123/349, 180/170, 180/179
• US Class Current: 701/93
• CPC Class Codes: B60K 31/047 the memory being digital
• CPC Class Codes: B60W 2050/001 Proportional integral [PI] controller
• CPC Class Codes: B60W 2050/0012 Feedforward or open loop systems
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2520/28 Wheel speed

Abstract

A vehicular constant-speed running system converges a vehicle speed control of a vehicle quickly to a target vehicle speed when the vehicle is set in a cruise control mode. The vehicular constant-speed running system includes a constant-speed running section for controlling a throttle opening independently of an accelerator opening to maintain a vehicle at a target vehicle speed. It also includes an initial opening setting section which, at the time of transfer by the constant-speed running section, sets the throttle opening before the transfer to an initial value at the time of the transfer if the throttle opening is in a region which is preset based on either the vehicle speed at the time of the transfer or a parameter correlated with the vehicle speed. If the throttle opening is not in this region, the initial opening setting section sets the same throttle opening to the upper limit and/or the lower limit of that region.

Claims

1. A vehicular constant-speed running system comprising:

constant-speed running means for controlling a throttle opening independently of an accelerator setting to maintain a vehicle at a target vehicle speed during a constant-speed running mode; and

initial opening setting means for setting, at a time of transfer to said constant-speed running mode, a throttle opening before said transfer to an initial throttle opening value of said constant speed running mode, if said throttle opening before said transfer is in a region preset based on a parameter correlated to said vehicle speed, and setting at least one of an upper limit and a lower limit of said region to said initial throttle opening value if said throttle opening before said transfer is not in said region.

2. The system of claim 1, wherein said parameter correlating to said vehicle speed is rotational speed of drive wheels of said vehicle.

3. The system of claim 1, wherein said parameter correlating to said vehicle speed is rotational speed of an engine of said vehicle.

4. The system of claim 1, wherein said constant-speed running means includes means for setting a target throttle opening by computing a proportional term and an integral term said throttle opening based on a difference between said target vehicle speed and a drive wheel speed and by adding said proportional term and said integral term.

5. A constant-speed running system for a vehicle, said system comprising:

material delivery means for regulating flow of a medium to an engine of said vehicle in accordance with a degree of actuation of said delivery means;

control means for controlling said degree of actuation of said delivery means;

an accelerator connected to said control means, said control means being for controlling said degree of actuation of said delivery means responsive to a setting of said accelerator during a manual running mode;

mode setting means for transferring control to a constant-speed running mode in which a speed of said vehicle is maintained at a target vehicle speed from said manual running mode, and for transferring control to said manual running mode from said constant-speed running mode;

constant-speed running means for controlling said degree of actuation of said throttle independently of said setting of said accelerator during said constant-speed running mode, said control means being for controlling said degree of actuation of said delivery means responsive to said constant-speed running means during said constant-speed running mode;

range determining means for determining whether a degree of actuation of said delivery means before transfer of control to said constant-speed running mode is within a given region;

initial opening setting means for setting, at a time of transfer to said constant-speed running mode, a degree of delivery means actuation before said transfer to an initial delivery means actuation value, responsive to a determination by said range determining means that said degree of actuation of said delivery means before said transfer is within said region, and to a given value responsive to a determination by said range determining means that said degree of actuation of said delivery means is not within said region; and

actuation degree restoring means for setting said degree of actuation of said delivery means to said degree of delivery means actuation before said transfer when said mode setting means transfers control from said constant-speed running mode to said manual running mode.

6. The system of claim 5, wherein said material delivery means is a throttle.

7. The system of claim 5, wherein said engine is an internal combustion engine.

8. The system of claim 5, wherein said medium is air.

9. The system of claim 5, wherein said region is based on a parameter representative of a speed of said vehicle.

10. The system of claim 9, wherein said parameter is rotational speed of drive wheels of said vehicle.

11. The system of claim 9, wherein said parameter is rotational speed of said engine.

12. The system of claim 5, wherein said value is one of an upper limit and a lower limit of said region.

13. The system of claim 5, wherein said initial opening setting means is for setting, at a time of transfer to said constant-speed running mode, an upper limit of said region to said initial delivery means actuation value responsive to a determination by said range determining means that said degree of actuation of said delivery means before said transfer is greater than said upper limit of said region.

14. The system of claim 5, wherein said initial opening setting means is for setting, at a time of transfer to said constant-speed running mode, a lower limit of said region to said initial delivery means actuation value responsive to a determination by said range determining means that said degree of actuation of said delivery means before said transfer is less than said lower limit of said region.

15. The system of claim 5, wherein said constant-speed running means includes means for setting a target delivery means actuation degree by computing a proportional term and an integral term of said delivery means actuation degree based on a difference between said target vehicle speed and a drive wheel speed and by adding said proportional term and said integral term.

16. A method of performing cruise control on an engine of a vehicle, said method comprising the steps of:

regulating flow of a medium to an engine of said vehicle using a delivery control device;

controlling a degree of actuation of said delivery control device, said control being performed responsive to a setting of an accelerator during a manual running mode and responsive to a controller, independently of said accelerator, during said constant-speed running mode;

transferring a control mode from said manual running mode to said constant-speed running mode;

determining whether a degree of actuation of said delivery control device before performing said transferring step is within a given region;

setting a degree of delivery control device actuation before performing said transferring step to an initial delivery control device actuation value responsive to a determination by said determining step that said degree of actuation of said delivery control device is within said region, and to a given value responsive to a determination by said determining step that said degree of actuation of said delivery control device before performing said transferring step is not within said region;

changing said control mode from said constant-speed running mode to said manual running mode; and

resetting said degree of actuation of said delivery control device to said degree of actuation of said delivery control device before performing said transferring step responsive to performance of said changing step.

17. The method of claim 16, wherein said setting step comprises a step of setting said degree of delivery control device actuation before performing said transferring step to one of an upper limit of said region and a lower limit of said range responsive to said determination by said determining step that said degree of actuation of said delivery control device is not within said region.

18. The method of claim 16, wherein said setting step comprises a step of setting an upper limit of said region to said initial delivery means actuation value responsive to a determination by said determining step that said degree of actuation of said delivery control device before performing said transforming step is above said upper limit of said region.

19. The method of claim 16, wherein said setting step comprises a step of setting a lower limit of said region to said initial delivery means actuation value responsive to a determination by said determining step that said degree of actuation of said delivery control device before performing said transferring step is below said lower limit of said region.

20. The method of claim 16, further comprising a step of setting a target delivery means actuation degree by computing a proportional term and an integral term of said delivery means actuation degree based on a difference between said target vehicle speed and a drive wheel speed and by adding said proportional term and said integral term.