Engine variable transmission control system

• US 5,406,483 A
• Filed: 03/22/1994
• Issued: 04/11/1995
• Est. Priority Date: 05/15/1991
• Status: Expired due to Fees

• Current Assignee: Phoenix International Corp (Deere & Company)
• Original Assignee: Phoenix International Corp (Deere & Company)
• Inventors: Batcheller, Barry D., Kallis, Adrian G., Brekkestran, Kevin L., Needham, Charles D.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/216,250
• Time in Patent Office: 385 Days
• Field of Search: 364/424.1, 364/424.01, 364/424.03, 364/426.03, 364/424.04, 364/900, 364/569, 123/352, 123/357, 123/365, 123/385, 123/386, 192/3.3, 192/3.54, 192/3.55, 74/731.1, 74/761, 74/752, 477/110, 477/111, 477/120, 477/154, 477/155, 477/160, 477/131, 477/109, 477/163
• US Class Current: 701/53
• CPC Class Codes: B60R 16/0315 using multiplexing techniques multiplexing for transmission of signals G08C15/00; multiplexing for electrical communication in general H04J
• 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 10/11 Stepped gearings
• CPC Class Codes: B60W 2050/0045 using databus protocols
• CPC Class Codes: B60W 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60Y 2200/14 Trucks; Load vehicles, Busses
• CPC Class Codes: F16H 2059/006 Overriding automatic control
• CPC Class Codes: F16H 2059/084 Economy mode
• CPC Class Codes: F16H 2059/085 Power mode
• CPC Class Codes: F16H 2059/743 using engine performance or power for control of gearing transmission input torque F16H2059/147
• CPC Class Codes: F16H 2061/0012 Transmission control for optimising power output of driveline
• CPC Class Codes: F16H 2061/0015 Transmission control for optimising fuel consumptions
• CPC Class Codes: F16H 2061/0255 Solenoid valve using PWM or duty-cycle control
• CPC Class Codes: F16H 2061/1208 with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 2061/122 Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 59/40 Output shaft speed
• CPC Class Codes: F16H 59/44 : dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 61/0213 : characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/08 : Timing control
• CPC Class Codes: F16H 61/12 : Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/684 : without interruption of drive
• CPC Class Codes: F16H 61/70 : specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements
• CPC Class Codes: F16H 63/36 : Interlocking devices
• CPC Class Codes: Y10T 74/19223 : Disconnectable counter shaft
• CPC Class Codes: Y10T 74/19251 : Control mechanism
• CPC Class Codes: Y10T 74/1926 : Speed responsive
• CPC Class Codes: Y10T 74/194 : Selective

Abstract

An electronic transmission control system for a self-propelled off-road vehicle having an internal combustion engine and multiple gear powershift transmission. The control system controls the powershift transmission and provides at least one control signal to the engine for selecting the speed at which the engine is to operate. The system includes a first electronic controller that provides transmission control signals required to command the powershift transmission to shift to and operate in any particular one of its forward gears, and second electronic controller that provides at least one engine control signal required to command the engine to operate at one of a number of different desired engine speeds and to monitor the actual engine speed. By use of gear ranges which overlap slightly, and a throttle that is infinitely adjustable within a range of engine speeds, any given ground speed within the range of possible vehicle speeds can be achieved and maintained, as long as engine is operating within its overall power envelope. Once the desired ground speed is specified by the operator, the control system automatically selects the specific transmission gear and engine speed required to achieve the desired ground speed. The control system also performs automatic upshifts or downshifts, as required, to achieve the desired ground speed. The system has a comfort mode, fuel economy mode, and a maximum horsepower mode, all selectable by the operator. The system also supports a pseudo-gear mode where the operator interface indicates there are more gears in the transmission than actually exist.

Claims

1. An electronic control system for a self-propelled off-road vehicle having an internal combustion engine and a powershift transmission with a plurality of forward gears, said control system being for controlling powershift transmission and providing at least one control signal to said engine for specifying a speed at which said engine of said vehicle is to operate, said control system comprising:

mode selection means for allowing an operator of said vehicle to select a desired one of a plurality of operating modes including a maximum fuel economy mode, a comfort mode and a maximum horsepower mode;

speed selection means for allowing said operator to select a desired vehicle ground speed;

first electronic controller means responsive to said mode selection means and said speed selection means and operable under stored program control for providing transmission control signals that specify in which specific one of said plurality of forward gears said powershift transmission is to operate in accordance with said selected operating mode; and

second electronic controller means operable under stored program control for providing at least one engine control signal required to command said engine to operate at one of a plurality of different engine speeds within a predetermined range in accordance with said desired vehicle ground speed,

said first electronic controller means including first electrical output means for commanding said powershift transmission to operate in a controller selected one of said plurality of forward gears in response to said gear as specified by the current transmission control signals, and communications means for sending and receiving digital signals to and from said second electronic controller means,

said second electronic controller means including second electrical output means for commanding said engine to operate at a particular one of said plurality of engine speeds indicated by said engine control signal, and communications means for sending and receiving digital signals to and from said first electronic controller means; and

when in said maximum fuel economy mode said electronic control system selects particular ones of said plurality of forward gears and particular ones of said engine speeds to minimize fuel consumption of said engine, said electronic control system further allowing said engine speed to vary slightly to help achieve minimum fuel consumption while attempting to maintain an operator selected vehicle ground speed;

when in said comfort mode said electronic control system selects particular ones of said plurality of forward gears and particular ones of said plurality of engine speeds to maintain an actual vehicle ground speed approximately equal to said operator selected vehicle ground speed while simultaneously reducing the number of shifts of said powershift transmission by varying said engine speed as necessary to compensate for changing loads experienced by said vehicle; and

when in said maximum horsepower mode said electronic control means selects various ones of said plurality of gears and varies said engine speed in an attempt to maintain said operator selected vehicle ground speed approximately equal to said actual vehicle ground speed while simultaneously maintaining said engine operating at one of said plurality of engine speeds that produces a maximum horsepower at said operator selected vehicle ground speed.

2. An electronic control system as in claim 1, further comprising:

display means, responsive to at least one of said controller means, for indicating to said operator the gear in which said powershift transmission is currently operating and said speed at which said engine is operating.

3. An electronic system as in claim 2, wherein:

said display means is operated by a selected one of said first and second controller means, and

said selected one of said first and second controller means receives information from the other of the controller means to be displayed via said display means.

4. An electronic system as in claim 1, further comprising:

interface means for enabling an operator to select any gear at which said transmission is to be operated; and

operator interface means for enabling said operator to select a desired one of said engine speeds within a predetermined range of allowable ones of said engine speeds at which said powershift transmission is to be operated.

5. An electronic system as in claim 1, wherein said first controller means further includes:

automatic means for, upon receipt of an upshift command, controlling a shift of said powershift transmission from a present gear to a higher gear;

automatic means for, upon receipt of a downshift command, controlling a shift of said powershift transmission from a present gear to a lower gear;

automatic means for generating a sequence of successive upshift commands, with each said upshift command occurring at a predetermined interval of time after completion of a shift by said transmission in response to a previous said upshift command if any in the sequence; and

automatic means for generating a sequence of successive downshift commands, with each said downshift command occurring at a predetermined interval of time after completion of a previous said downshift command by said powershift transmission.

6. An electronic system as in claim 1, wherein said first controller means further includes:

automatic means for determining, based at least in part upon vehicle ground speed, which gear to shift to next.

7. An electronic system as in claim 6, wherein said automatic means for determining includes means for checking whether ground speed matching is to be used to provide the next shift.

8. An electronic system as in claim 1 in which said powershift transmission has a series of hydraulic clutch packs and associated solenoid-operated control valves for causing said clutch packs to be filled when its associated valve has its solenoid energized, and wherein said first controller means further includes:

means for storing specific information from which to determine time delays to be used when shifting said powershift transmission from any given gear said powershift transmission is in to any other desired gear; and

automatic means for carrying out shifts of said powershift transmission in accordance with said time delays determined from said stored specific information.

9. An electronic system as in claim 1, wherein said first controller means further includes:

means for receiving signals having a period inversely related to said ground speed of said vehicle, means for determining from said received signals said ground speed of said vehicle, and means for storing said ground speed as a digital value for use by said automatic means for determining which gear to shift to next.

10. An electronic system as in claim 9, wherein said received signals whose period is inversely related to said ground speed are obtained from a rotating component directly connected to an output power shaft of said vehicle and thereby provides an indication of apparent ground speed.

11. An electronic system as in claim 9, wherein said received signals whose period is inversely related to said ground speed are obtained from a mechanism which provides an indication of said actual vehicle ground speed.

12. An electronic system as in claim 1, further comprising means for producing a control signal corresponding to a throttle position selected by said operator of said vehicle, and

wherein said second controller means further includes:

automatic means, responsive to changes in said control signal for modifying changes to said control signal in response to changes in said throttle position selected by said operator.

13. An electronic control system for a self-propelled off-road vehicle having an internal combustion engine and multiple gear powershift transmission, said electronic control system being for controlling said powershift transmission and providing at least one control signal to said engine for selecting a speed at which said engine operates, said electronic control system comprising:

means for receiving an operator selected desired vehicle ground speed,

mode selection means for allowing an operator of said vehicle to select a desired one of a plurality of operating modes including a maximum fuel economy mode, a maximum horsepower mode and a comfort mode;

electronic controller means for providing transmission control signals required to command said powershift transmission to operate in any given one of its said forward gears, and for providing at least one engine control signal required to command said engine to operate at any given speed within a range of possible engine speeds,

said electronic controller means including first electrical output means for causing said powershift transmission to operate in a given transmission gear as indicated by said transmission control signals, second electrical output means for causing said engine to operate at a given engine speed as indicated by said engine control signal, and first automatic means, responsive to said means for receiving an operator selected desired vehicle speed, for selecting a transmission gear and then a desired engine speed required to achieve said desired vehicle speed;

first means responsive to said mode selection means for causing said electronic control system to control shifting of said powershift transmission and to vary said engine speed of said vehicle as needed to obtain maximum fuel economy, while attempting to maintain an actual ground speed of said vehicle approximate equal to said desired vehicle ground speed, when said maximum fuel economy mode is selected;

second means responsive to said mode selection means for causing said electronic control system to control shifting of said powershift transmission and to vary said engine speed of said vehicle as needed to cause maximum horsepower to be generated by said engine while simultaneously attempting to maintain said actual ground speed of said vehicle approximately equal to said desired vehicle ground speed; and

third means responsive to said mode selection means for causing said electronic control system to control shifting of said powershift transmission and to vary said engine speed of said vehicle as needed to reduce the number of shifts of said powershift transmission in response to changing vehicle loads while simultaneously maintaining said desired vehicle ground speed approximately equal to an actual vehicle ground speed when operating in said comfort mode.

14. A control system as in claim 13, wherein said electronic controller means operates under stored program control.

15. A control system as in claim 14, wherein:

said electronic controller means includes first and second electronic controllers, each said controller including communications means for passing information back and forth to the other said controller, and each said controller being operable under the control of a distinct stored program.

16. A control system as in claim 14, further comprising:

display means, connected to and receiving display signals from said controller means, for indicating to said operator a current vehicle speed, a current gear in which the transmission is operating, and a current engine speed at which said engine is operating.

17. A control system as in claim 14, wherein said electronic controller further includes:

second automatic means, responsive to said selected transmission gear and said desired engine speed, for shifting said transmission through ones of said plurality of gears necessary to cause said powershift transmission to reach said selected transmission gear; and

third automatic means, responsive to said selected engine speed, for causing said engine to achieve said desired engine speed.

18. A control system as in claim 17, wherein said second automatic means, in order to eliminate any significant difference between said actual engine speed and said desired engine speed, for generating a series of gear shift commands, with each one of said gear shift commands occurring a predetermined interval of time after completion of a previous one of said gear shift commands, if any in said series.

19. A control system as in claim 18, wherein said electronic controller means further includes:

means for adjusting said predetermined interval of time after completion of a previous one of said gear shift commands, depending upon how close said desired engine speed is to said actual engine speed.

20. An electronic system as in claim 13, wherein said controller means further includes:

automatic means for determining, based at least in part upon said actual vehicle ground speed, which one of said plurality of gears to shift to next.

21. An electronic system as in claim 20, wherein said automatic means for determining which gear to shift to next includes means for checking whether ground speed matching is to be used to help specify said one gear to be shifted to.

22. An electronic control system for a self-propelled off-road vehicle having an internal combustion engine and a powershift transmission having a plurality of forward gears, said control system controlling said powershift transmission and providing at least one control signal to said engine for selecting a speed at which said engine operates, said control system comprising:

means for receiving an operator selected desired vehicle speed;

means for enabling an operator to select one of a plurality of modes in which said engine may be operated, said modes including at least a fuel economy model a maximum power mode and a comfort mode; and

electronic controller means for providing transmission control signals required to command said powershift transmission in any particular one of its said forward gears, and at least one engine control signal required to command said engine to operate at one speed within a range of possible engine speeds, and wherein

said controller means, in response to said selection of a maximum power mode selects, for said desired vehicle speed, a transmission gear and an engine speed which produces substantially maximum output horsepower from said, and in response to a selection of said fuel economy mode selects, for said desired vehicle speed, a transmission gear and an engine speed corresponding to substantially optimal fuel economy from said engine for said desired vehicle ground speed, and in response to selection of said comfort mode causes said transmission gears to be selected and varies said engine speed as necessary to minimize the number of shifts required by said powershift transmission while simultaneously maintaining an actual ground speed of said vehicle approximately equal to said desired vehicle ground speed in spite of changing loads experienced by said vehicle; and

said maximum power mode causing said electronic control system to control shifting of said powershift transmission and said engine speed of said engine to cause maximum horsepower to be generated by said engine at said desired vehicle ground speed.

23. A control system as in claim 22, wherein the electronic controller means comprises first electrical output means for commanding said powershift transmission to operate in a particular desired transmission gear as indicated by said transmission control signals, and

second electrical output means for commanding said engine to operate at a particular engine speed indicated by said engine control signal, and

first automatic means, responsive to the means for enabling operator selection of one of said plurality of modes, for selecting successive transmission gears required to achieve said particular desired transmission gear, and then a suitable engine speed as required to achieve said desired vehicle speed.