System and method for controlling downhill vehicle operation

• US 6,349,253 B1
• Filed: 11/13/1998
• Issued: 02/19/2002
• Est. Priority Date: 11/13/1998
• Status: Expired due to Term

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Bellinger, Steven M.
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): Broadhead, Brian J.
• Application Number:
  US09/192,009
• Time in Patent Office: 1,194 Days
• Field of Search: 701/53, 701/54, 701/61, 701/64, 701/83, 701/86, 701/93, 701/94, 701/95, 701/97, 701/99, 701/100, 701/101, 701/112, 477/24, 477/27, 477/32, 477/40, 477/94, 477/115, 477/118, 477/183, 477/185
• US Class Current: 701/53
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/18136 Engine braking
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60Y 2400/435 Supercharger or turbochargers
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02D 17/023 the inactive cylinders acting as compressor other than for pumping air into the exhaust system
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/12 for deceleration F02D41/0005, F02D41/107 take precedence

Abstract

A system for controlling downhill vehicle operation includes an electronically actuatable engine compression brake unit associated with an internal combustion engine, an electronically controllable turbocharger boost pressure adjustment device, electronically actuatable service brakes and a transmission including a number of automatically selectable gear ratios, wherein each of these components are coupled to a control computer. In accordance with one aspect of the present invention, the control computer is operable to detect a potential runaway vehicle condition and control any one or combination of engine compression brake activity, turbocharger boost pressure, service brake activity and automatic transmission shifting to thereby provide for a controlled descent down a negative grade and thereby prevent a runaway vehicle condition. In accordance with another aspect of the present invention, the control computer is operable to determine a target engine or vehicle speed and control engine or vehicle speed to the target speed, regardless of whether a potential runaway vehicle condition exists, using any one or more of the foregoing control techniques.

Claims

1. System for controlling downhill vehicle operation, comprising:

an engine compression brake associated with an internal combustion engine for retarding engine operation;

a service brake associated with a vehicle carrying said engine;

a transmission coupled to said engine and having a number of automatically selectable gear ratios;

means for determining one of a target engine and vehicle speed;

means for determining whether said vehicle is traversing a negative grade; and

a control computer responsive to detection of said vehicle traversing a negative grade to control said engine compression brake, said service brake and selection of said number of automatically selectable gear ratios of said transmission to thereby control one of engine and vehicle speed to a corresponding one of said target engine speed and said target vehicle speed, said control computer activating said service brake only to an extent necessary to slow said vehicle sufficiently to allow an automatic downshift of said transmission.

2. The system of claim 1 further including means for determining a deceleration rate;

and wherein said control computer is operable to control any of said engine compression brake, said service brake and selection of said number of automatically selectable gear ratios of said transmission to thereby control one of engine and vehicle speed to a corresponding one of said target engine speed and said target vehicle speed at said deceleration rate.

3. The system of claim 2 wherein said means for determining a deceleration rate includes:

means for sensing one of engine and vehicle speed and producing a current speed signal corresponding thereto;

and wherein said control computer includes;

means for determining a speed error as a difference between said current speed signal and a corresponding one of said target engine speed and said target vehicle speed; and

means for determining said deceleration rate as a first deceleration rate if said speed error is in excess of a predefined threshold and as a second deceleration rate is said speed error is below said predefined threshold.

4. The system of claim 1 further including:

a turbocharger; and

a wastegate valve operable to control turbocharger boost pressure;

and wherein said control computer is further responsive to detection of said vehicle traversing a negative grade to control said wastegate valve to thereby control said one of engine and vehicle speed to said corresponding one of said target engine speed and said target vehicle speed.

5. The system of claim 4 further including means for determining a deceleration rate;

and wherein said control computer is operable to control any of said engine compression brake, said wastegate valve, said service brake and selection of said number of automatically selectable gear ratios of said transmission to thereby control one of engine and vehicle speed to a corresponding one of said target engine speed and said target vehicle speed at said deceleration rate.

6. The system of claim 5 wherein said means for determining a deceleration rate includes:

means for sensing one of engine and vehicle speed and producing a current speed signal corresponding thereto;

and wherein said control computer includes;

means for determining a speed error as a difference between said current speed signal and a corresponding one of said target engine speed and said target vehicle speed; and

means for determining said deceleration rate as a first deceleration rate if said speed error is in excess of a predefined threshold and as a second deceleration rate is said speed error is below said predefined threshold.

7. The system of claim 1 wherein said control computer is associated with said transmission and is operable to control and manage overall operation of said transmission;

and further including;

an engine computer operable to control and manage overall operation of said internal combustion engine; and

means for transferring data between said control computer and said engine computer.

8. The system of claim 1 further including means for determining one of engine speed and vehicle speed;

and wherein said control computer includes means responsive to said one of engine speed and vehicle speed for computing said one of a target engine speed and a target vehicle speed as a learned one of said engine speed and vehicle speed over a recent interval of one of time and distance traveled.

9. The system of claim 1 further including a cruise control system having means for establishing a first set vehicle speed;

and wherein said control computer is operable to equate said one of a target engine speed and a target vehicle speed with a corresponding one of an engine speed associated with said first set vehicle speed.

10. The system of claim 9 further including means for establishing a second set vehicle speed;

and wherein said control computer is operable to disregard said first set vehicle speed and equate said one of a target engine speed and a target vehicle speed with a corresponding one of an engine speed associated with said second set vehicle speed.

12. The system of claim 10 wherein said means for establishing a second set vehicle speed includes an operator interface system in communication with said control computer, said operator interface system including means for selecting said second set vehicle speed.

13. The system of claim 10 wherein said means for establishing a second set vehicle speed includes:

a global positioning system (GPS) operable to determine GPS coordinates of said vehicle;

means for determining a vehicle location from said GPS coordinates; and

means for determining said second set vehicle speed from said vehicle location.

14. The system of claim 1 wherein said control computer is further operable to control and manage overall operation of said internal combustion engine.

11. The system of claim 11 wherein said means for establishing a second set vehicle speed includes a cruise control system having means for establishing said second set vehicle speed.

15. A method of controlling downhill operation of a vehicle carrying an internal combustion engine having an engine brake and coupled to a transmission having a number of automatically selectable gear ratios, comprising the steps of:

determining whether the vehicle is traversing a negative grade;

determining one of a target engine speed and a target vehicle speed;

performing the following steps if the vehicle is traversing a negative grade;

determining one of a current engine and vehicle speed; and

controlling any of an engine brake associated with said engine, a service brake associated with said vehicle and selection of said number of automatically selectable gear ratios of said transmission to thereby control said one of current engine and vehicle speed to a corresponding one of said target engine speed and said target vehicle speed, said control computer activating said service brake only to an extent necessary to slow said vehicle sufficiently to allow an automatic downshift of said transmission.