[go: up one dir, main page]

FR2755205A1 - METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR - Google Patents

METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR Download PDF

Info

Publication number
FR2755205A1
FR2755205A1 FR9613034A FR9613034A FR2755205A1 FR 2755205 A1 FR2755205 A1 FR 2755205A1 FR 9613034 A FR9613034 A FR 9613034A FR 9613034 A FR9613034 A FR 9613034A FR 2755205 A1 FR2755205 A1 FR 2755205A1
Authority
FR
France
Prior art keywords
pedal
control method
information
previous
speed
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.)
Granted
Application number
FR9613034A
Other languages
French (fr)
Other versions
FR2755205B1 (en
Inventor
Eric Boitard
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.)
Renault SA
Original Assignee
Renault SA
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 Renault SA filed Critical Renault SA
Priority to FR9613034A priority Critical patent/FR2755205B1/en
Priority to PCT/FR1997/001906 priority patent/WO1998019082A1/en
Publication of FR2755205A1 publication Critical patent/FR2755205A1/en
Application granted granted Critical
Publication of FR2755205B1 publication Critical patent/FR2755205B1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • F16H59/141—Inputs being a function of torque or torque demand of rate of change of torque or torque demand
    • 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
    • F16H61/02—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 characterised by the signals used
    • F16H61/0202—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 characterised by the signals used the signals being electric
    • F16H61/0204—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 characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
    • F16H61/0213—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 characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal characterised by the method for generating shift signals

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Transmission Device (AREA)

Abstract

The invention concerns a method for controlling the passage of an automatic gearbox to a reduced gear ratio using the accelerator pedal (1) of a vehicle, characterised in that it relies on the simultaneous exploitation of a first information linked to the position of the pedal, and a second information linked to the speed of its depression by the driver.

Description

PROCEDE DE COMMANDE DU PASSAGE D'UNE
TRANSMISSION AUTOMATIOUE SUR UN RAPPORT
INFERIEUR
La présente invention concerne la commande des transmissions automatiques à rapports étagés. Plus précisément, elle a pour objet un procédé de commande du passage d'une transmission automatique sur un rapport inférieur à l'aide de la pédale d'accélérateur.METHOD FOR CONTROLLING THE PASSAGE OF A
AUTOMATED TRANSMISSION ON A REPORT
INFERIOR
The present invention relates to the control of automatic transmissions with stepped reports. More specifically, it relates to a method for controlling the passage of an automatic transmission to a lower gear using the accelerator pedal.

Les boîtes de vitesses automatiques pilotées électroniquement disposent généralement d'une commande de rétrogradage par enfoncement de la pédale d'accélérateur, permettant au conducteur de forcer la boîte à rétrograder jusqu'au rapport le plus faible, dans une limite déterminée par le fonctionnement du moteur.Electronically controlled automatic gearboxes generally have a downshift control by depressing the accelerator pedal, allowing the driver to force the gearbox to downshift to the lowest gear, within a limit determined by engine operation .

Selon une disposition classique, le conducteur demande ces rétrogradages en appuyant à fond sur la pédale d'accélérateur, de façon à dépasser un point dur. Le passage de ce point dur ferme un contact électrique, appelé "rétro-contact", qui informe l'unité de pilotage électronique de la boîte, de la demande de rétrogradage.According to a conventional arrangement, the driver requests these downshifts by depressing the accelerator pedal fully, so as to pass a hard point. The passage of this hard point closes an electrical contact, called "retro-contact", which informs the electronic control unit of the gearbox, of the demotion request.

Lorsque le rétro-contact intervient en fin de course de la pédale, le conducteur est contraint d'accélérer "pied à fond", pour obtenir un rétrogradage. When the retro-contact occurs at the end of the pedal stroke, the driver is forced to accelerate "fully" to obtain a downshift.

D'une façon générale, le système du rétro-contact, ou "kick-down", à point dur en fin de course présente l'inconvénient d'être relativement inconfortable pour le conducteur, de sorte qu'il est peu ou rarement utilisé.In general, the feedback system, or "kick-down", hard point at the end of the race has the disadvantage of being relatively uncomfortable for the driver, so that it is rarely or rarely used .

La présente invention vise à mettre en oeuvre une fonction de rétrogradage pouvant intervenir en différents points de la course de l'accélérateur, et sans incidence sur la résistance à l'enfoncement de celle-ci.The present invention aims to implement a downshift function which can intervene at different points of the accelerator stroke, and without affecting the resistance to depression thereof.

Elle propose dans ce but d'exploiter simultanément une première information liée à la position de la pédale, et une seconde information liée à sa vitesse d'enfoncement par le conducteur.To this end, it proposes to simultaneously use a first piece of information linked to the position of the pedal, and a second piece of information linked to its speed of depressing by the driver.

Selon un premier mode de réalisation de l'invention, la première information est relative à l'angle d'inclinaison de la pédale par rapport à sa position de repos, et la seconde information est relative à sa vitesse angulaire de déplacement à l'écart de sa position de repos.According to a first embodiment of the invention, the first information relates to the angle of inclination of the pedal relative to its rest position, and the second information relates to its angular speed of displacement away from its rest position.

Selon un second mode de réalisation de l'invention, la première information est relative à l'écart en distance de la pédale par rapport à sa position de repos, et la seconde information est relative à sa vitesse linéaire de déplacement.According to a second embodiment of the invention, the first item of information relates to the distance in distance of the pedal from its rest position, and the second item of information relates to its linear speed of movement.

D'autres caractéristiques et avantages de l'invention apparaîtront clairement à la lecture de la description suivante d'un mode de réalisation particulier de celle-ci, en liaison avec les dessins annexés, sur lesquels
- la figure unique illustre le procédé de l'invention
Sur la figure 1, on a représenté schématiquement une pédale d'accélérateur 1 et le calculateur électronique 2 d'une boîte de vitesses automatique, auquel elle transmet les informations nécessaires au passage de la transmission sur un rapport inférieur, conformément à l'invention.Other characteristics and advantages of the invention will appear clearly on reading the following description of a particular embodiment thereof, in conjunction with the appended drawings, in which
- the single figure illustrates the process of the invention
In Figure 1, there is shown schematically an accelerator pedal 1 and the electronic computer 2 of an automatic gearbox, to which it transmits the information necessary for the transmission to pass through a lower gear, in accordance with the invention.

Comme indiqué plus haut, le conducteur d'un véhicule automobile équipé d'une boîte de vitesses automatique a besoin dans certaines circonstances de disposer d'une accélération importante, et exprime ce besoin en appuyant plus ou moins fortement sur sa pédale d'accélérateur, selon le caractère d'urgence de la situation. Etant donné que l'intensité de l'accélération souhaitée influe non seulement sur la position de pédale recherchée, mais également sur la rapidité de son action, l'invention propose de prendre en considération simultanément la position de la pédale, et sa vitesse d'enfoncement pour commander le passage sur un rapport inférieur. As indicated above, the driver of a motor vehicle equipped with an automatic gearbox needs in certain circumstances to have a significant acceleration, and expresses this need by pressing more or less strongly on his accelerator pedal, depending on the urgency of the situation. Since the intensity of the desired acceleration influences not only the desired pedal position, but also the speed of its action, the invention proposes to take into consideration simultaneously the position of the pedal, and its speed. push to control shift to a lower gear.

Conformément à l'invention, le calculateur de la boîte de vitesses automatique du véhicule exploite donc une première information relative à la position de la pédale, et une seconde information, relative à sa vitesse d'enfoncement. Sur la base de ces signaux, il développe une stratégie, lui permettant de décider d'imposer à la transmission le passage sur un rapport inférieur, ou de ne pas imposer ce passage. En d'autres termes, le procédé de commande proposé, se traduit par un signal de commande interne du calculateur de la boîte, appelé signal kick , qui peut prendre deux valeurs (1, ou 0), correspondant respectivement à l'acceptation ou au refus du passage sur un rapport inférieur.According to the invention, the computer of the automatic gearbox of the vehicle therefore uses a first item of information relating to the position of the pedal, and a second item of information relating to its speed of depressing. On the basis of these signals, he develops a strategy, allowing him to decide to impose on the transmission the shift to a lower gear, or not to impose this shift. In other words, the proposed control method results in an internal control signal from the gearbox computer, called a kick signal, which can take two values (1, or 0), corresponding respectively to acceptance or to refusal to switch to a lower gear.

Conformément à l'invention, les informations exploitées peuvent être représentatives du déplacement linéaire de la pédale, ou de son déplacement linéaire. Dans les deux cas, le calculateur compare deux variables liées à la position de la pédale, à deux seuils d'autorisation préétablis. Un premier seuil définit la position de la pédale à partir de laquelle le rétrogradage est enclenché, tandis que le second définit un seuil de vitesse d'enfoncement qui est comparé par le calculateur à la dérivée de la position pédale, avant d'autoriser le passage sur un rapport inférieur.In accordance with the invention, the information used can be representative of the linear displacement of the pedal, or of its linear displacement. In both cases, the computer compares two variables related to the position of the pedal, with two preset authorization thresholds. A first threshold defines the position of the pedal from which the downshift is engaged, while the second defines a depressing speed threshold which is compared by the computer to the derivative of the pedal position, before authorizing the shift. on a lower gear.

Si le critère de déplacement retenu se rapporte à la position angulaire de la pédale, la position instantanée de la pédale peut par exemple être exprimée en degrés d'angle pédale par rapport à sa position de repos. Le premier et le second seuil seront alors établis respectivement en degrés et en degrés par seconde.If the displacement criterion adopted relates to the angular position of the pedal, the instantaneous position of the pedal can for example be expressed in degrees of pedal angle relative to its rest position. The first and the second threshold will then be established respectively in degrees and in degrees per second.

Si ce critère concerne la position linéaire de la pédale sur sa course, la position. instantanée de la pédale sera par exemple exprimée en millimètres d'écart par rapport à sa position de repos, et les deux seuils retenus, seront établis respectivement en millimètres et en millimètres par seconde. If this criterion concerns the linear position of the pedal on its stroke, the position. instantaneous pedal will for example be expressed in millimeters of deviation from its rest position, and the two thresholds selected, will be established respectively in millimeters and millimeters per second.

Les opérations de contrôle du calculateur s'effectuent en suivant la boucle suivante. Lors de l'initialisation du procédé, le signal kick du calculateur reçoit la valeur "refusé" (O). En donnant un signe positif à la dérivée de la position pédale dans le sens de l'enfoncement de celle-ci, la valeur accepté (1) est adoptée dès que l'écart de la pédale vis-à-vis de sa position de repos est supérieurs au premier seuil, et que la valeur de sa vitesse d'enfoncement est supérieure au second. Conformément à l'invention, la valeur (1) est conservée jusqu'à ce que l'écart en position de la pédale redevienne inférieur au premier seuil.The control operations of the computer are carried out by following the following loop. When the process is initialized, the kick signal from the computer receives the value "refused" (O). By giving a positive sign to the derivative of the pedal position in the direction in which it is depressed, the accepted value (1) is adopted as soon as the deviation of the pedal from its rest position is greater than the first threshold, and that the value of its penetration speed is greater than the second. According to the invention, the value (1) is kept until the difference in position of the pedal becomes less than the first threshold.

Bien entendu, tant que le signal conserve sa valeur d'acceptation, les passages sur des rapports inférieurs sont déclenchés, pour autant que la charge du moteur le permette. En particulier, si la demande d'accélération du conducteur nécessite plusieurs rétrogradages, les mesures proposées, garantissent leur déroulement successif dans les meilleures conditions de confort, sans manoeuvre supplémentaire du conducteur. D'une manière générale, l'efficacité des mesures proposées, permet d'éviter tout rétrogradage intempestif, et leur transparence vis-à-vis de l'utilisateur conferent au procédé de commande de l'invention un intérêt considérable. Of course, as long as the signal retains its acceptance value, changes to lower gears are triggered, provided that the load of the engine allows it. In particular, if the driver's acceleration request requires several downshifts, the measures proposed guarantee their successive progress in the best conditions of comfort, without additional maneuver by the driver. In general, the effectiveness of the proposed measures makes it possible to avoid any untimely demotion, and their transparency vis-à-vis the user confer considerable importance on the control method of the invention.

Claims (8)

REVENDICATIONS vitesse d'enfoncement par le conducteur. la position de la pédale, et une seconde information liée à sa sur l'exploitation simultanée d'une première information liée à d'accélérateur (1) du véhicule, caractérisé en ce qu'il repose automatique sur un rapport inférieur à l'aide de la pédaleCLAIMS driving speed by the driver. the position of the pedal, and a second piece of information linked to its on the simultaneous operation of a first piece of information linked to the accelerator (1) of the vehicle, characterized in that it is based automatically on a lower ratio using of the pedal [1] Procédé de commande du passage d'une transmission[1] Method for controlling the passage of a transmission déplacement à l'écart de sa position de repos. moving away from its rest position. seconde information est relative à sa vitesse angulaire de second information relates to its angular speed of pédale (1) par rapport à sa position de repos, et en ce que la pedal (1) relative to its rest position, and in that the que la première information est relative à l'inclinaison de la that the first information relates to the inclination of the [2] Procédé de commande selon la revendication 1, caractérisé en[2] Control method according to claim 1, characterized in déplacement. displacement. la seconde information est relative à sa vitesse linéaire de the second information relates to its linear speed of de la pédale (1) par rapport à sa position de repos, et en ce que of the pedal (1) relative to its rest position, and in that ce que la première information est relative à l'écart en distance what the first information relates to the distance difference [3] Procédé de commande selon la revendication 1, caractérisé en[3] Control method according to claim 1, characterized in second seuil préétablis.  second preset threshold. et sa vitesse d'enfoncement sont supérieurs à un premier et à un and its penetration speed are greater than a prime and a inférieur est accepté lorsque l'écart en position de la pédale (1), lower is accepted when the deviation in pedal position (1), précédentes, caractérisé en ce que le passage sur un rapport previous, characterized in that switching to a gear [4] Procédé de commande selon l'une des revendications[4] Control method according to one of claims position reste supérieur au premier seuil. position remains above the first threshold. ce que l'ordre de passage reste valide tant que l'écart de that the order of passage remains valid as long as the deviation of [5] Procédé de commande selon la revendication 4, caractérisé en[5] Control method according to claim 4, characterized in du véhicule. of the vehicle. exploitées par le calculateur (2) de la transmission automatique operated by the automatic transmission computer (2) précédentes, caractérisé en ce que les informations sont previous, characterized in that the information is [6] Procédé de commande selon l'une des revendications[6] Control method according to one of claims rapport inférieur. lower ratio. signal binaire d'acceptation ou de refus du passage sur un binary signal of acceptance or refusal of passage on a précédentes, caractérisé en ce que le signal de commande est un previous, characterized in that the control signal is a [7] Procédé de commande selon l'une des revendications[7] Control method according to one of claims rétrogradages successifs.  successive downshifts. précédentes, caractérisé en ce qu'il peut imposer plusieurs previous, characterized in that it can impose several [8] procédé de commande selon l'une des revendications[8] control method according to one of claims
FR9613034A 1996-10-25 1996-10-25 METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR Expired - Fee Related FR2755205B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR9613034A FR2755205B1 (en) 1996-10-25 1996-10-25 METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR
PCT/FR1997/001906 WO1998019082A1 (en) 1996-10-25 1997-10-24 Method for controlling the passage of an automatic gearbox to a reduced gear ratio

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR9613034A FR2755205B1 (en) 1996-10-25 1996-10-25 METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR

Publications (2)

Publication Number Publication Date
FR2755205A1 true FR2755205A1 (en) 1998-04-30
FR2755205B1 FR2755205B1 (en) 1998-11-27

Family

ID=9497027

Family Applications (1)

Application Number Title Priority Date Filing Date
FR9613034A Expired - Fee Related FR2755205B1 (en) 1996-10-25 1996-10-25 METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR

Country Status (2)

Country Link
FR (1) FR2755205B1 (en)
WO (1) WO1998019082A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2863092B1 (en) 2003-12-02 2007-05-18 Renault Sas SYSTEM FOR DISPLAYING THE RECOMMENDED GEARBOX RATIO

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5083480A (en) * 1988-11-28 1992-01-28 Nissan Motor Coompany, Limited Shift control system for automotive automatic power transmission with kick-down control according to prediction of demanded engine load
US5233523A (en) * 1990-12-21 1993-08-03 Ford Motor Company Compensation for delay of scheduled gearshifts in automatic transmissions
US5319998A (en) * 1990-11-15 1994-06-14 Toyota Jidosha Kabushiki Kaisha Method for downshifting of automatic transmission with discrimination of magnitude of need therefor
JPH06221415A (en) * 1991-08-12 1994-08-09 Aisin Aw Co Ltd Automatic speed change point changing speed change control device using throttle opening speed and acceleration

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07119814A (en) * 1993-10-25 1995-05-12 Mitsubishi Motors Corp Shift control device for automatic transmission
GB9505176D0 (en) * 1995-03-15 1995-05-03 Automotive Products Plc Vehicle transmissions
JP3191239B2 (en) * 1995-12-14 2001-07-23 株式会社ユニシアジェックス Transmission control device
JPH09166207A (en) * 1995-12-18 1997-06-24 Unisia Jecs Corp Control device for transmission

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5083480A (en) * 1988-11-28 1992-01-28 Nissan Motor Coompany, Limited Shift control system for automotive automatic power transmission with kick-down control according to prediction of demanded engine load
US5319998A (en) * 1990-11-15 1994-06-14 Toyota Jidosha Kabushiki Kaisha Method for downshifting of automatic transmission with discrimination of magnitude of need therefor
US5233523A (en) * 1990-12-21 1993-08-03 Ford Motor Company Compensation for delay of scheduled gearshifts in automatic transmissions
JPH06221415A (en) * 1991-08-12 1994-08-09 Aisin Aw Co Ltd Automatic speed change point changing speed change control device using throttle opening speed and acceleration

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 018, no. 594 (M - 1703) 14 November 1994 (1994-11-14) *

Also Published As

Publication number Publication date
FR2755205B1 (en) 1998-11-27
WO1998019082A1 (en) 1998-05-07

Similar Documents

Publication Publication Date Title
US7451845B2 (en) Adjustment of the speed of a motor vehicle with an automatic gearbox
FR2721367A1 (en) Device and method for controlling an automatic gearshift device of a gearbox of a motor vehicle.
FR2731659A1 (en) SPEED LIMITATION METHOD AND DEVICE FOR MOTOR VEHICLES
EP0889264B1 (en) Speed change ratio controller for continuously variable transmission
JP3627613B2 (en) Driving force control device for automobile
JP4862742B2 (en) Internal combustion engine control device and internal combustion engine control system
EP0819227B1 (en) Automated mechanical gearbox system including improved control means for when the vehicle is stationary
CN108216212A (en) Control the system and method for turn inside diameter
FR2870791A1 (en) SYSTEM FOR CONTROLLING KINETIC VEHICLE CHARACTERISTICS
EP1481876A1 (en) Method for controlling an electric power steering mechanism for a motor vehicle
FR2755205A1 (en) METHOD FOR CONTROLLING THE TRANSFER OF AN AUTOMATIC TRANSMISSION ON A LOWER GEAR
WO2004088176A1 (en) Automatic speed-change control device
FR2697784A1 (en) Controller augmenting slowing of vehicle travelling in neutral - uses monitoring of gear ratio and road speed and increases engine speed to sustain lubrication if vehicle is in neutral
EP0819066B1 (en) Mechanical gearbox control system including wheel skid preventing means
US6871130B2 (en) Method of controlling an automatic transmission
JP3463527B2 (en) Control device for continuously variable transmission
FR2774955A1 (en) CLUTCH CONTROL SYSTEM
EP1034962B1 (en) Apparatus and method for control of inter-vehicle spacing
FR2646128A1 (en) DEVICE FOR AUTOMATICALLY ACTUATING A CLUTCH
FR2873422A1 (en) METHOD FOR CONTROLLING REPORTING CHANGES IN COMMUNICATIONS OF PASSING LAWS OR VARIOGRAMS
FR2729343A1 (en) Management of continuously variable automobile transmissions
FR2746887A1 (en) SYSTEM FOR DETERMINING VARIATIONS IN THE RATIO OF AN AUTOMATIC TRANSMISSION
WO2005080123A1 (en) Device and method for driving a motor vehicle traction chain whose transmission member has an automatically changeable gearing reduction mode and a motor vehicle provided with said device
JPH07198029A (en) Control method of gear ratio of continuously variable transmission of automobile
EP1344963B1 (en) Procedure and device for control of changing speed in an automatic or automatized transmission

Legal Events

Date Code Title Description
TP Transmission of property
ST Notification of lapse

Effective date: 20070629