System for controlling drivetrain components to achieve fuel efficiency goals

• US 6,957,139 B2
• Filed: 02/11/2003
• Issued: 10/18/2005
• Est. Priority Date: 06/18/1998
• Status: Expired due to Term

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Bellinger, Steven M.
• Primary Examiner(s): Argenbright, Tony M.
• Assistant Examiner(s): Hoang, Johnny H.
• Application Number:
  US10/364,263
• Publication Number:
  US 20040002806A1
• Time in Patent Office: 980 Days
• Field of Search: 701/101, 701/102, 701/103, 701/104, 701/109, 477/111, 477/109
• US Class Current: 701/104
• CPC Class Codes: B60T 2250/02 Vehicle mass
• 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 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2050/0042 Transfer function lag; delays
• CPC Class Codes: B60W 2050/0066 using buttons or a keyboard connected to the on-board processor
• CPC Class Codes: B60W 2510/0609 Throttle change rate
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/105 Output torque
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2530/16 Driving resistance
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/215 Selection or confirmation of options
• CPC Class Codes: B60W 2540/30 Driving style
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2555/60 Traffic rules, e.g. speed limits or right of way
• CPC Class Codes: B60W 2555/80 : Country specific, e.g. driver age limits or right hand drive
• CPC Class Codes: B60W 2556/50 : of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: B60W 2710/0677 : Engine power
• CPC Class Codes: B60W 2720/10 : Longitudinal speed
• CPC Class Codes: B60W 2720/106 : Longitudinal acceleration
• CPC Class Codes: B60W 30/1819 : Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60W 30/1882 : characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: B60W 50/082 : Selecting or switching between different modes of propelling
• CPC Class Codes: B60W 50/085 : Changing the parameters of the control units, e.g. changing limit values, working points by control input
• CPC Class Codes: F02D 2041/2048 : said control involving a limitation, e.g. applying current or voltage limits
• CPC Class Codes: F02D 2200/0404 : Throttle position
• CPC Class Codes: F02D 2200/0614 : Actual fuel mass or fuel injection amount
• CPC Class Codes: F02D 2200/1002 : Output torque
• CPC Class Codes: F02D 2200/1004 : Estimation of the output torque
• CPC Class Codes: F02D 2200/1012 : Engine speed gradient
• CPC Class Codes: F02D 2200/501 : Vehicle speed
• CPC Class Codes: F02D 2200/602 : Pedal position
• CPC Class Codes: F02D 2200/701 : Information about vehicle position, e.g. from navigation system or GPS signal
• CPC Class Codes: F02D 2200/702 : Road conditions
• CPC Class Codes: F02D 2250/26 : by applying a torque limit
• CPC Class Codes: F02D 2400/12 : Engine control specially adapted for a transmission comprising a torque converter or for continuously variable transmissions
• CPC Class Codes: F02D 31/009 : for maximum speed control
• CPC Class Codes: F02D 41/0225 : in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/023 : in relation with the gear ratio shifting conjoint control for improving gear change B60W30/19
• CPC Class Codes: F02D 41/1497 : With detection of the mechanical response of the engine
• CPC Class Codes: F02D 41/2406 : using essentially read only memories
• CPC Class Codes: F02D 41/2422 : Selective use of one or more tables
• CPC Class Codes: F16H 2059/663 : Road slope
• CPC Class Codes: F16H 2059/666 : Determining road conditions by using vehicle location or position, e.g. from global navigation systems [GPS]
• CPC Class Codes: F16H 2061/0015 : Transmission control for optimising fuel consumptions
• CPC Class Codes: F16H 2061/022 : Calculation or estimation of optimal gear ratio, e.g. best ratio for economy drive or performance according driver preference, or to optimise exhaust emissions
• CPC Class Codes: F16H 59/52 : dependent on the weight of the machine, e.g. change in weight resulting from passengers boarding a bus
• CPC Class Codes: F16H 61/0213 : characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/66 : specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38
• CPC Class Codes: F16H 63/50 : Signals to an engine or motor
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A system for controlling a vehicle drivetrain in a fuel-efficient manner includes a control computer operable to define a contour from substantially zero engine load to substantially full engine load, wherein the contour may correspond to a fuel-efficient path from no-load to full-load engine operating conditions. With change gear transmissions, the control computer is operable to control transmission shift points about the contour. With continuous variable transmissions the control computer is operable to modify the effective gear ratio thereof to maintain engine operation on or about the contour. In either case, fuel efficient operation may be optimized.

Claims

1. A system for controlling a vehicle drivetrain, comprising:

a memory having stored therein an engine output characteristics map of an internal combustion engine and a contour associated with said map extending from a low engine load value to a high engine load value thereof;

means for determining at least one engine operating parameter; and

a control computer responsive to said at least one engine operating parameter to control shift points of a transmission coupled to said engine as said at least one engine operating parameter approaches said contour.

2. The system of claim 1 wherein said contour corresponds to a substantially fuel efficient path extending between said low engine load value and said high engine load value.

3. The system of claim 2 wherein said low engine load value corresponds to a substantially zero engine load value and said high engine load value corresponds to a boundary of said engine output characteristics map.

4. The system of claim 1 wherein said control computer is operable to control upshift points of said transmission as said at least one engine operating parameter approaches said contour from a first side thereof and to control downshift points of said transmission as said at least one engine operating parameter approaches said contour from a second opposite side of said contour.

5. The system of claim 4 wherein said means for determining at least one engine operating parameter includes means for determining a rotational speed of said engine and producing an engine speed signal corresponding thereto;

and wherein said control computer is operable to control upshift points of said transmission if said engine speed signal indicates that current engine speed is approaching said contour with increasing engine speed, and wherein said control computer is operable to control downshift points of said transmission if said engine speed signal indicates that current engine speed is approaching said contour with decreasing engine speed.

6. The system of claim 5 wherein said means for determining at least one engine operating parameter further includes means for determining an engine load value;

and wherein said control computer is operable to control upshift points of said transmission if said engine speed signal and said engine load value indicate that current engine operating conditions are approaching said contour with increasing engine speed, and wherein said control computer is operable to control downshift points of said transmission if said engine speed signal and said engine load value indicate that current engine operating conditions are approaching said contour with decreasing engine speed.

7. The system of claim 5 wherein said transmission includes a number of automatically selectable gears;

and wherein said control computer is operable to control upshifting and downshifting between said automatically selectable gears by forcing upshifts and downshifts based on said engine speed signal to thereby maintain engine speed within predefined engine speed ranges of said contour.

8. The system of claim 7 wherein said control computer is an engine control computer operable to manage and control the overall operation of said engine.

9. The system of claim 7 wherein said control computer is a transmission control computer operable to manage and control the overall operation of said transmission.

10. The system of claim 5 wherein said transmission includes a number of manually selectable gears;

and wherein said control computer is operable to control upshifting and downshifting between said manually selectable gears by limiting engine speed about said contour to thereby encourage upshifting and downshifting with engine speed maintained within predefined engine speed ranges of said contour.

11. A method of controlling a vehicle drivetrain, comprising the steps of:

providing an engine output characteristics map for an internal combustion engine;

establishing a contour in relation to said map extending from a low engine load point to a high engine load point thereof;

determining an engine operating parameter;

controlling upshift points of a transmission coupled to said engine if said engine operating parameter approaches said contour from a first side thereof; and

controlling downshift points of said transmission if said engine operating parameter approaches said contour from a second opposite side thereof.

12. The method of claim 11 wherein said establishing step includes establishing said contour in accordance with a fuel efficient criterion to thereby establish a fuel efficient path between said low engine load point and said high engine load point.

13. The method of claim 11 wherein the step of controlling upshift points includes the steps of:

monitoring engine speed of said engine;

determining a first engine speed value when said engine operating parameter reaches said contour;

determining a gear step of a next higher gear of said transmission;

determining an engine speed shift point to said next higher gear as a function of said first engine speed and said gear step; and

when said engine speed reaches said engine speed shift point performing one of forcing an upshift to said next higher gear and limiting engine speed of said engine to said engine speed shift point.

14. The method of claim 11 wherein the step of controlling downshift points includes the steps of:

monitoring engine speed of said engine;

determining a first engine speed value when said engine operating parameter reaches said contour;

determining a gear step of a next lower gear of said transmission;

determining an engine speed shift point to said next lower gear as a function of said first engine speed and said gear step; and

when said engine speed reaches said engine speed shift point performing one of forcing a downshift to said next lower gear and limiting engine speed of said engine to said engine speed shift point.

15. A system for controlling a vehicle drivetrain, comprising:

a memory having stored therein an engine output characteristics map of an internal combustion engine and a contour associated with said map extending from a low engine load value to a high engine load value thereof;

means for determining at least one engine operating parameter; and

a control computer responsive to said at least one engine operating parameter to control an effective gear ratio of a continuous variable transmission (CVT) coupled to said engine to thereby maintain said at least one engine operating parameter within a predefined engine speed deviation from said contour.

16. The system of claim 15 wherein said contour corresponds to a substantially fuel efficient path extending between said low engine load value and said high engine load value.

17. The system of claim 16 wherein said low engine load value corresponds to a substantially zero engine load value and said high engine load value corresponds to a boundary of said engine output characteristics map.

18. The system of claim 15 wherein said engine speed deviation corresponds to zero engine speed deviation such that said control computer is operable to control an effective gear ratio of said CVT to thereby maintain said at least one engine operating parameter on said contour.

19. The system of claim 15 wherein said control computer is an engine control computer operable to manage and control the overall operation of said engine.

20. The system of claim 15 wherein said control computer is a transmission control computer operable to manage and control the overall operation of said CVT.

21. A method of controlling a vehicle drivetrain, comprising the steps of:

providing an engine output characteristics map for an internal combustion engine;

establishing a contour in relation to said map extending from a low engine load point to a high engine load point thereof;

determining an engine operating parameter; and

controlling an effective gear ratio of a continuous variable transmission (CVT) coupled to said engine to thereby maintain said engine operating parameter within a predefined engine speed deviation from said contour.

22. The method of claim 21 wherein said establishing step includes establishing said contour in accordance with a fuel efficient criterion to thereby establish a fuel efficient path between said low engine load point and said high engine load point.

23. The method of claim 21 wherein said predefined engine speed deviation is zero such that said controlling step comprises controlling said effective gear ratio of said CVT to thereby maintain said engine operating parameter on said contour.

24. A method of controlling a vehicle drivetrain, comprising the steps of:

providing an engine output characteristics map for an internal combustion engine;

determining at least one engine operating parameter in relation to said map;

monitoring engine speed of said engine;

if said engine speed is increasing along a boundary of said map, performing one of the following steps when said engine speed reaches a governed speed value;

forcing an upshift to a higher gear of a transmission coupled to said engine; and

limiting engine speed of said engine to said governed engine speed value.

25. A method of controlling a vehicle drivetrain, comprising the steps of:

providing an engine output characteristics map for an internal combustion engine;

determining at least one engine operating parameter in relation to said map;

monitoring engine speed of said engine;

if said engine speed is decreasing along a boundary of said map, determining an engine speed shift point as a function of a gear step between a presently engaged gear and a next lower gear of a transmission coupled to said engine and performing one of the following steps when said engine speed reaches said engine speed shift point;

forcing a downshift to said next lower gear of said transmission; and

limiting engine speed of said engine to said engine speed shift point.