System for controlling drivetrain components to achieve fuel efficiency goals

• US 6,546,329 B2
• Filed: 02/21/2002
• Issued: 04/08/2003
• 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): Vo, Hien T.
• Application Number:
  US10/080,049
• Publication Number:
  US 20020132699A1
• Time in Patent Office: 411 Days
• Field of Search: 701/115, 701/102, 701/103, 701/104, 701/110, 477/107, 477/111, 180/197, 123/480, 123/478, 123/350, 123/352
• US Class Current: 701/115
• 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, in one embodiment, a control computer operable to determine a number of engine load/engine speed boundary conditions as functions of brake specific fuel consumption (BSFC) contours in relation to an engine output characteristics map and define therefrom an undesirable engine operation region U. As long as the engine is engaged with at least one of the gear ratios of the vehicle transmission, the control computer is operable to maintain or encourage engine operation outside of the region U. In another embodiment, the control computer is operable to define a contour from substantially zero engine load to substantially full engine load, wherein the contour preferably corresponds 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 and a region thereof of undesirable engine operation;

a control computer operable to compute an estimated engine torque and an actual engine torque, said control computer allowing engine operation anywhere on or within said engine output characteristics map if said actual engine torque is greater than said estimated engine torque and otherwise maintaining or encouraging engine operation outside said region.

2. The system of claim 1 further including a vehicle speed sensor producing a vehicle speed signal indicative of vehicle speed;

wherein said control computer is operable to determine an aerodynamic drag force as a based on said vehicle speed signal, said control computer computing said estimated engine torque as a function of said aerodynamic drag force.

3. The system of claim 2 further including means for determining a vehicle mass value;

wherein said control computer is operable to determine a rolling resistance force based on said vehicle speed signal and on said vehicle mass value, said control computer computing said estimated engine torque as a further function of said rolling resistance force.

4. The system of claim 3 further including an engine speed sensor producing an engine speed signal indicative of engine rotational speed;

wherein said control computer is operable to determine a powertrain drag force based on said engine speed signal, said control computer computing said estimated engine torque as a further function of said powertrain drag force.

5. The system of claim 4 wherein said memory includes a road grade angle stored therein;

and wherein said control computer is operable to determine a drag force due to road grade based on said vehicle mass value and on said road grade angle, said control computer computing said estimated engine torque as a further function of said drag force due to road grade.

6. The system of claim 5 wherein said control computer is operable to determine a vehicle acceleration force based on said vehicle speed signal and on said vehicle mass value, said control computer computing said estimated engine torque as a further function of said vehicle acceleration force.

7. The system of claim 6 further including means for determining an overall drivetrain reduction value;

and wherein said control computer is operable to compute said estimated engine torque as a further function of said overall drivetrain reduction value.

8. The system of claim 7 further including:

means for determining a current engine fueling value; and

means for determining a maximum engine fueling value;

wherein said control computer is operable to compute said actual engine torque as a function of said current engine fueling value and said maximum engine fueling value.

9. The system of claim 8 further including:

means for determining at least one engine operating condition relating to said engine output characteristics map;

wherein said control computer is operable to compare said at least one engine operating condition with said engine output characteristics map and control engine operation according to said engine output characteristics map while maintaining or encouraging engine operation outside said region by limiting engine operation only to areas of said engine output characteristics map outside said region of undesirable engine operation.

10. The system of claim 1 further including:

means for establishing a driver reward/penalty; and

means for modifying an area or location of said region relative to said engine output characteristics map as a function of said driver reward/penalty.

11. The system of claim 1 further including:

means for determining a currently engaged gear ratio of a transmission coupled to an engine included within a vehicle drivetrain and producing a gear ratio value corresponding thereto;

means for determining vehicle speed of a vehicle carrying said engine and producing a vehicle speed signal corresponding thereto; and

means for modifying an area or location of said region relative to said engine output characteristics map as a function of one of said currently engaged gear ratio value and said vehicle speed signal.

12. The system of claim 1 further including:

means for determining current vehicle position of a vehicle carrying an engine forming part of a vehicle drivetrain; and

means for defining an area or location of said region relative to said engine output characteristics map as a function of said current vehicle position.

13. The system of claim 1 further including:

means for determining a current engine fueling value; and

means for determining a maximum engine fueling value;

wherein said control computer is operable to compute said actual engine torque as a function of said current engine fueling value and said maximum engine fueling value.

14. The system of claim 1 further including:

means for determining at least one engine operating condition relating to said engine output characteristics map;

wherein said control computer is operable to compare said at least one engine operating condition with said engine output characteristics map and control engine operation according to said engine output characteristics map while maintaining or encouraging engine operation outside said region by limiting engine operation only to areas of said engine output characteristics map outside said region of undesirable engine operation.

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

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

defining a region of said engine output characteristics map of undesirable engine operation;

determining an estimated engine torque value;

determining an actual engine torque value; and

controlling engine operation according to said engine output characteristics map while maintaining or encouraging engine operation outside said region if said actual engine torque is below said estimated engine torque.

16. The method of claim 15 further including the step of determining a vehicle speed value indicative of current vehicle speed;

and wherein the step of determining an estimated engine torque includes determining an aerodynamic drag force based on said vehicle speed value, said estimated engine torque a function of said aerodynamic drag force.

17. The method of claim 16 further including the step of determining a vehicle mass value indicative of vehicle mass;

and wherein the step of determining an estimated engine torque includes determining a rolling resistance force based on said vehicle speed value and on said vehicle mass value, said estimated engine torque further a function of said rolling resistance force.

18. The method of claim 17 further including the step of determining an engine speed value indicative of engine rotational speed;

and wherein the step of determining an estimated engine torque includes determining a powertrain drag force based on said engine speed value, said estimated engine torque further a function of said powertrain drag force.

19. The method of claim 18 further including the step of determining a road grade angle;

and wherein the step of determining an estimated engine torque includes determining a drag force due to road grade based on said road grade angle and on said vehicle mass value, said estimated engine torque further a function of said drag force due to road grade.

20. The method of claim 19 wherein the step of determining an estimated engine torque includes determining a vehicle acceleration force based on said vehicle speed value and on said vehicle mass value, said estimated engine torque further a function of said vehicle acceleration force.

21. The method of claim 20 further including the step of determining an overall drivetrain reduction value;

and wherein the step of determining an estimated engine torque includes determining said estimated engine torque as a further function of said overall drivetrain reduction value.

22. The method of claim 21 further including the steps of:

determining a current engine fueling value; and

determining a maximum engine fueling value;

and wherein the step of determining an actual engine torque includes determining said actual engine torque as a function of said current engine fueling value and said maximum engine fueling value.