GB2345522A - An automatic transmission having a driver operated control to provide increased acceleration - Google Patents

An automatic transmission having a driver operated control to provide increased acceleration Download PDF

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Publication number
GB2345522A
GB2345522A GB9900349A GB9900349A GB2345522A GB 2345522 A GB2345522 A GB 2345522A GB 9900349 A GB9900349 A GB 9900349A GB 9900349 A GB9900349 A GB 9900349A GB 2345522 A GB2345522 A GB 2345522A
Authority
GB
United Kingdom
Prior art keywords
motor vehicle
engine speed
ratio
control unit
electronic control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9900349A
Other versions
GB9900349D0 (en
Inventor
Adrian Hilary Berry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MG Rover Group Ltd
Original Assignee
MG Rover Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MG Rover Group Ltd filed Critical MG Rover Group Ltd
Priority to GB9900349A priority Critical patent/GB2345522A/en
Publication of GB9900349D0 publication Critical patent/GB9900349D0/en
Publication of GB2345522A publication Critical patent/GB2345522A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/06—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of combustion engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/10—Conjoint control of vehicle sub-units of different type or different function including control of change-speed gearings
    • B60W10/101—Infinitely variable gearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B60W30/1819—Propulsion control with control means using analogue circuits, relays or mechanical links
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
    • F16H59/14—Inputs being a function of torque or torque demand
    • F16H59/18—Inputs being a function of torque or torque demand dependent on the position of the accelerator pedal
    • F16H59/20—Kickdown
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • General Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Transmission Device (AREA)
  • Control Of Driving Devices And Active Controlling Of Vehicle (AREA)

Abstract

An automatic transmission 11, preferably a continuously variable transmission (CVT), has an electronic control unit 12 and sensor means to provide signals indicative of the speed of the engine 10 and road. A driver operable control 17, which is preferably mounted on the steering wheel, reduces the ratio of the CVT to a ratio resulting in an engine speed close to that at which peak engine torque is produced (fig 2).

Description

A Motor Vehicle This invention relates to a motor vehicle and in particular to the control of an automatic or continuously variable transmission fitted to a motor vehicle.
It is well known to provide a motor vehicle with an automatic or continuously variable transmission that is automatically controlled by an electronic control unit to vary the ratio of the transmission. The control of such transmissions is normally effected to provide good economy from the motor vehicle and so tries to maintain the engine operating near to a speed at which its specific fuel consumption is at a minimum.
It is an object of this invention to provide a motor vehicle having improved acceleration for overtaking purposes.
According to the invention there is provided a motor vehicle having an engine, an automatic transmission driven by the engine, an electronic control unit to control the automatic transmission and sensor means to provide signals indicative of engine speed and road speed to the electronic control unit wherein there is a driver operable control connected to the electronic control unit to override the normal operation of the automatic transmission so as to provide a lower ratio than would normally be selected by the electronic control unit for the respective road speed.
The motor vehicle may include an accelerator pedal having a position sensor to send a signal indicative of position to the electronic control unit.
Preferably, the automatic transmission is a continuously variable transmission and operation of the driver operable control causes the electronic control unit to reduce the ratio of the continuously variable transmission to a ratio resulting in an engine speed close to that at which peak engine torque is produced.
The reduced ratio may be held until the driver operable control is released or until the engine speed reaches a pre-determined engine speed or, until the driver operable control is operated again.
The pre-determined engine speed may be dependant upon the position of the accelerator pedal.
The pre-determined speed may be an engine speed close to that at which maximum power is produced.
The reduced ratio may be released if the accelerator pedal is moved to a reduced demand position.
Operation of the driver operable control may cause the electronic control unit to reduce the ratio of the continuously variable transmission by a predetermined amount.
The reduced ratio may be held until the driver operable control is released or until the engine speed reaches a pre-determined engine speed or, until the driver operable control is operated again.
The pre-determined engine speed may be an engine speed close to that at which maximum power is produced or may be dependant upon the position of the accelerator pedal.
The reduced ratio may be released if the accelerator pedal is moved to a reduced demand position. The driver operable control may be a switch mounted on a steering wheel of the motor vehicle.
The invention will now be described by way of example with reference to the accompanying of which : Fig. l is a schematic representation of a motor vehicle according to the invention; and Fig. 2 is a graph showing the relationship between power and torque for a hypothetical engine of a motor vehicle.
With reference to Figs. 1 and 2 there is shown a motor vehicle 5 having a body structure 6 supporting an engine 10. The engine 10 drives a continuously variable transmission 11 which is connected by means of an output shaft 15 to the front road wheels (not shown) of the motor vehicle 5.
The engine 10 and the transmission 11 are controlled by an electronic control unit 12. The electronic control unit receives a signal indicative of engine speed from an engine speed sensor 14 and sends a signal representative of a required power to a fuel and air supply unit 20.
A road speed sensor (not shown) is used to supply a signal to the electronic control unit 12 that is indicative of road speed.
The continuously variable transmission 11 is operable between a minimum ratio between the engine 10 and the output shaft 15 and a maximum ratio between the engine 10 and the output shaft 15. The ratio is selected by an electronically controlled transmission ratio controller 13 connected to the electronic control unit 12 from which it receives signals indicative of the required ratio.
When the continuously variable transmission 11 is operating at its minimum or lowest ratio the output shaft 15 will be rotated relatively slowly with respect to the rotational speed of the engine 10. When the transmission 11 is at its maximum or highest ratio the difference in speed between the output shaft 15 and the engine 10 will not be so great.
An accelerator pedal 18 is pivotally connected to part of the body structure 6 of the motor vehicle. A position sensor 19 is attached to the accelerator pedal 18 to provide a signal to the electronic control unit 12 indicative of the required demand input from a driver of the motor vehicle.
As the accelerator pedal 18 is depressed the signal sent from the sensor 19 indicates that the greater demand for more power is required from the engine 10.
As the accelerator pedal 18 is released the signal sent from the sensor 19 indicates that less power is required. By this means the driver is able to control the speed of the motor vehicle 5.
A steering wheel 16 is provided to enable a driver of the motor vehicle to provide an input indicative of a required direction of travel. A driver operable control in the form of a switch 17 is attached to part of the steering wheel 16. The switch 17 is connected to the electronic control unit 12 and is operable to provide a signal indicative that maximum acceleration is required.
With particular reference to Fig. 2 there is shown a typical power curve"P" and a typical torque curve"T"for an internal combustion engine 10. The engine 10 has a peak torque condition occurring at an engine speed"NT'and a peak power condition occurring at an engine speed"NP".
During normal operation the electronic control unit 12 will control the transmission 11 by means of the controller 13 to ensure that the engine speed remains close to the engine speed N1 corresponding to that speed at which its specific fuel consumption for the engine 10 is at a minimum.
When the driver operates the switch 17 the normal automatic control of the transmission 11 by the electronic control unit is overridden and the electronic control unit 12 sends a signal to the controller 13 causing the ratio of the transmission 11 to be rapidly reduced until the engine speed rises to a level"N2" that is slightly above or below the engine speed at which peak torque occurs.
This gearbox ratio is then held so long as the button 17 is depressed or until the engine speed has risen close to the speed"NP"at which maximum power occurs.
However, if at any time the driver reduces the demand position of the accelerator pedal 18 or removes the pressure from the switch 17 the lower ratio will be released and the continuously variable transmission will revert to normal automatic control.
In accordance with a first modification of the invention the electronic control unit is arranged to operate such that the reduced ratio is held until the engine speed reaches a pre-determined engine speed somewhere between the engine speed"N'I 'corresponding to maximum torque and the engine speed"NP" corresponding to the-maximum power dependant upon the position of the accelerator pedal 18.
For example, if the accelerator pedal 18 is sensed to be fully depressed then the pre-determined engine speed will be close to"NP"corresponding to the maximum power speed of the engine. However, if the position of the accelerator pedal 18 corresponds to a 60% demand position then the lower ratio will only be held until the engine speed has risen to a percentage of"NP"which may for example be 70%. Once again, the accelerator pedal is released to a reduced demand position or the switch 17 is released then the electronic control unit 12 reverts to automatic control of the transmission 11 and the ratio of the transmission will be rapidly increased to reduce the speed of rotation of the engine 10.
In accordance with a second embodiment of the invention, operation of the switch 17 causes the electronic control unit to reduce the ratio of the transmission by a pre-determined amount. The amount by which the ratio of the transmission is reduced is dependant upon the position of the accelerator pedal 18.
For example, if the accelerator pedal is fully depressed the ratio is reduced by 50% whereas if the accelerator pedal is only depressed 60% the ratio is reduced by 25%.
In either case, the reduced ratio will be released if the accelerator pedal 18 is moved to a reduced demand position.
Alternatively, the automatic transmission could be of the multi ratio type have pre-determined fixed gear ratios in which case the reduction in ratio is determined by the respective gear ratios available, however, it is possible for a ratio to be selected that is not the next lower one in the series but one or more ratios below that.
For example, in heavy traffic on a light throttle the automatic transmission may normally select the highest ratio, say fourth gear but operation of the driver operable control will result in second gear being instantaneously selected and not third gear.
It will be appreciated that the switch used to effect selection of the lower ratio could be mounted at any convenient position for use by the driver of the motor vehicle. For example, the switch could be mounted on the dashboard or as part of a control stalk extending from the steering column.
The switch could be of the hold-on type described above or could be of a pushon/push-off type in which the lower ratio would be held until the switch is operated again.

Claims (17)

  1. CLAIMS 1. A motor vehicle having an engine, an automatic transmission driven by the engine, an electronic control unit to control the automatic transmission and sensor means to provide signals indicative of engine speed and road speed to the electronic control unit wherein there is a driver operable control connected to the electronic control unit to override the normal operation of the automatic transmission so as to provide a lower ratio than would normally be selected by the electronic control unit for the respective road speed.
  2. 2. A motor vehicle as claimed in Claim 1 in which the motor vehicle includes an accelerator pedal having a position sensor to send a signal indicative of position to the electronic control unit.
  3. 3. A motor vehicle as claimed in Claim 1 or in Claim 2 in which the automatic transmission is a continuously variable transmission and operation of the driver operable control causes the electronic control unit to reduce the ratio of the continuously variable transmission to a ratio resulting in an engine speed close to that at which peak engine torque is produced.
  4. 4. A motor vehicle as claimed in Claim 3 in which the reduced ratio is held until the driver operable control is released.
  5. 5. A motor vehicle as claimed in Claim 3 in which the reduced ratio is held until the engine speed reaches a pre-determined engine speed.
  6. 6. A motor vehicle as claimed in Claim 3 in which the reduced ratio is held until the driver operable control is operated again.
  7. 7. A motor vehicle as claimed in Claim 5 when dependant upon Claim 2 in which the pre-determined engine speed is dependant upon the position of the accelerator pedal.
  8. 8. A motor vehicle as claimed in Claim 5 in which the pre-determined speed is an engine speed close to that at which maximum power is produced.
  9. 9. A motor vehicle as claimed in Claim 3 when dependant upon Claim 2 in which the reduced ratio is released if the accelerator pedal is moved to a reduced demand position.
  10. 10.-A motor vehicle as claimed in Claim 3 in which operation of the driver operable control causes the electronic control unit to reduce the ratio of the continuously variable transmission by a pre-determined amount.
  11. 11. A motor vehicle as claimed in Claim 10 in which the reduced ratio is held until the driver operable control is released.
  12. 12. A motor vehicle as claimed in Claim 10 in which the reduced ratio is held until the engine speed reaches a pre-determined engine speed.
  13. 13. A motor vehicle as claimed in Claim 12 in which the pre-determined engine speed is an engine speed close to that at which maximum power is produced.
  14. 14. A motor vehicle as claimed in Claim 12 when Claim 3 is dependant upon Claim 2 in which the pre-determined engine speed is dependant upon the position of the accelerator pedal.
  15. 15. A motor vehicle as claimed in any of Claims 10 to 14 when dependant upon Claim 2 in which the reduced ratio is released if the accelerator pedal is moved to a reduced demand position.
  16. 16. A motor vehicle as claimed in any preceding claim in which the driver operable control is a switch mounted on a steering wheel of the motor vehicle.
  17. 17. A motor vehicle substantially as described herein with reference to the accompanying drawing.
GB9900349A 1999-01-09 1999-01-09 An automatic transmission having a driver operated control to provide increased acceleration Withdrawn GB2345522A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9900349A GB2345522A (en) 1999-01-09 1999-01-09 An automatic transmission having a driver operated control to provide increased acceleration

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9900349A GB2345522A (en) 1999-01-09 1999-01-09 An automatic transmission having a driver operated control to provide increased acceleration

Publications (2)

Publication Number Publication Date
GB9900349D0 GB9900349D0 (en) 1999-02-24
GB2345522A true GB2345522A (en) 2000-07-12

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9900349A Withdrawn GB2345522A (en) 1999-01-09 1999-01-09 An automatic transmission having a driver operated control to provide increased acceleration

Country Status (1)

Country Link
GB (1) GB2345522A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2910100A1 (en) * 2006-12-18 2008-06-20 Renault Sas METHOD FOR CONTROLLING A CONTINUOUSLY VARIABLE AUTOMATIC TRANSMISSION FOR A MOTOR VEHICLE.
CN106043303A (en) * 2015-04-14 2016-10-26 福特全球技术公司 Vehicle control in traffic conditions

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0026470A2 (en) * 1979-10-01 1981-04-08 Regie Nationale Des Usines Renault Regulation process for a motorized propulsion unit, and device to carry it into effect
DE4311852A1 (en) * 1993-03-19 1994-09-22 Bosch Gmbh Robert Operating device for the manual actuation of the shift sequence of a vehicle transmission
GB2303183A (en) * 1993-03-31 1997-02-12 Bosch Gmbh Robert Method for operating electronically controlled CVT has additional manual control
GB2310470A (en) * 1996-02-20 1997-08-27 Fuji Heavy Ind Ltd A continuously-variable transmission for a vehicle with automatic and manual control modes
DE19609787A1 (en) * 1996-03-13 1997-09-18 Bosch Gmbh Robert Hydraulic emergency control for a continuously variable belt transmission with an extended manual valve

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0026470A2 (en) * 1979-10-01 1981-04-08 Regie Nationale Des Usines Renault Regulation process for a motorized propulsion unit, and device to carry it into effect
DE4311852A1 (en) * 1993-03-19 1994-09-22 Bosch Gmbh Robert Operating device for the manual actuation of the shift sequence of a vehicle transmission
GB2303183A (en) * 1993-03-31 1997-02-12 Bosch Gmbh Robert Method for operating electronically controlled CVT has additional manual control
GB2310470A (en) * 1996-02-20 1997-08-27 Fuji Heavy Ind Ltd A continuously-variable transmission for a vehicle with automatic and manual control modes
DE19609787A1 (en) * 1996-03-13 1997-09-18 Bosch Gmbh Robert Hydraulic emergency control for a continuously variable belt transmission with an extended manual valve

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2910100A1 (en) * 2006-12-18 2008-06-20 Renault Sas METHOD FOR CONTROLLING A CONTINUOUSLY VARIABLE AUTOMATIC TRANSMISSION FOR A MOTOR VEHICLE.
WO2008074948A1 (en) * 2006-12-18 2008-06-26 Renault S.A.S Method for controlling a continuously variable automatic transmission for a motor vehicle
CN106043303A (en) * 2015-04-14 2016-10-26 福特全球技术公司 Vehicle control in traffic conditions

Also Published As

Publication number Publication date
GB9900349D0 (en) 1999-02-24

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732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)