FR2798173A1 - AUTOMATIC TRANSMISSION SYSTEM - Google Patents

Abstract

This system comprises a clutch (14) disengaged when moving the speed lever (24) from the neutral position to a forward mode and reset in a first mode, depending on the speed of the engine, the system comprising for this purpose clutch engaging means (22, 38), a gearbox (12), a gear engaging mechanism (25) and further means (56) for operating a brake (58) of the vehicle and switching means for starting at a high speed of the motor, the transmission system being operable in a second mode after the actuation of the brake (58) and switching means for increasing the speed of the motor without reclosing the motor. 'clutch.Application including automatic transmission systems for the sporty driving of automobiles.

Description

I

  The present invention relates to automatic transmission systems

  and transmission systems having a coupling as a main drive clutch, clutch operating means for controlling the engagement state of the clutch, a multi-gearbox , a gear engagement mechanism for engaging an active ratio in the gearbox, a driving mode selector operable by a driver and allowing the driver to select the neutral position or a driving mode;

forward.

  German Patent Application DE 1991132 proposes an automatic transmission system, in which a starting from the off state can be activated for an increased engine speed, by increasing the speed of the engine while the forward mode selector is in the neutral position. Moving the forward mode selector to its forward mode then causes the transmission system to engage a starter gear and engage the clutch in a controlled manner. Although this system can provide a faster start than performing a start at idle speed, then opening the throttle valve,

  there is still a delay after the execution of the start to engage

speed of starting.

  The purpose of this is to provide a transmission system as described above, which reduces or eliminates the disadvantages

previously mentioned.

  The present invention provides an automatic transmission system providing possibilities for executing sports starts

or race starts.

  According to one aspect of the present invention, a transmission system

  automatic includes a coupling as a driving clutch.

  main element, clutch operating means for controlling the engagement state of the clutch, a gearbox for

  multiple reports, a speed commitment mechanism for engagement

  transmission of an active ratio in the gearbox, a mode selector able to be actuated by a driver and allowing the driver to select the neutral position or a mode of operation, characterized in that it further comprises means switching means for executing a high speed start and electronic control means for controlling the clutch actuating means, that the control means is adapted to disengage the clutch for engagement of a higher speed when of the movement of the operating mode selector from the neutral in an operating mode, and for controlling, in the first mode, a reclosing of the clutch as a function of the speed of the engine, that the control means also comprise means for detecting the actuation of a brake of the vehicle, and that, in a second mode, the control means are adapted for, when actuating the brake and the switching means ion, allow an increase in the speed of the engine without reclosing the clutch, the control means

  being adapted, in the second mode, to bring the means of

  the clutch to reset the clutch, when releasing the clutch

switching means.

  In accordance with the present invention, the high speed start can be triggered by the operation of the vehicle brake and switching means after the forward mode selector is moved from the neutral position to a forward mode. for switching on a start speed. In this second mode, the engine speed can be increased while the starting speed is engaged, without reclosing the clutch in accordance with the normal starting procedure. Engagement of the clutch can

  then be triggered by release of the switching means.

  Preferably with semi-automatic transmission systems

  or fully automatic, the starting speed can be selected

  automatically when moving the forward mode selector. With fully automatic transmissions, the speed can be selected automatically by the control unit, so that the driver does not need to intervene in the selection of the

  speed at least in one mode of operation of the transmission.

  However with manual transmission systems with an automatic clutch, the starting speed is manually selected by

  move the forward mode selector.

  According to another embodiment of the invention, for engines with exhaust gas turbocharger, when the brake and the switching means are actuated, the control means can allow a partial pre-engagement of the clutch to charge the engine.

  engine and increase the pressure of the turbocharger.

  According to a preferred embodiment of the invention, the brake and the switching means must be actuated for a predetermined time interval, typically for 5 seconds.

  before starting at a high speed is triggered. A warning

  The audible and / or visual indication may be issued at the end of this period to indicate to the driver that starting in a high speed mode is activated. After this activation, the brake can be released and the switching means are not released unless the reclosing of the clutch

is required.

  Preferably for semi-automatic transmission systems, the switching means used to initiate high speed starting and to control the clutch reclosing in this mode are the ratio select switch. Other switching means may be used, for example a brake lock switch of the type found in rally cars or means of switching.

dedicated switching.

  When releasing the switching means, the reclosing

  the clutch is controlled to provide maximum acceleration

  male, preferably with a gentle forward start, which avoids excessive wear and overheating of the clutch, and prevents stalling of the engine. In addition, the clutch can be controlled to produce positive torque traction control to prevent slippage.

wheels.

  Other advantageous features of the present invention

  will emerge from the description given below taken with reference to the drawings

  attached, in which: - Figure 1 shows a schematic view of a semi-automatic transmission system according to the present invention; FIG. 2 represents a flowchart illustrating the steps implemented during the control of the transmission in accordance with the present invention; and Figure 3 shows a typical plot of engine speed and clutch disc speed versus time for high engine speed starting.

  with the transmission system shown in Figure 1.

  Figure 1 of the accompanying drawings shows a motor 10 having a starter and a circuit O10a which is associated with the starter and is coupled through the forward main friction clutch 14 and an input shaft of the box. multiple transmission speeds

  gears 12, for example a transmission with three shafts, including several

  synchronized transmission reports. The fuel is sent to the engine by means of a throttle device 16, which includes a throttle valve 18 actuated by an accelerator pedal 19. The invention is also applicable to a gasoline engine or a diesel engine at

  electronic or mechanical fuel injection.

  The clutch 14 is actuated by a release fork 20, which is actuated by a hydraulic receiver cylinder 22, under the control of

  means 38 for controlling the actuator actuating the clutch.

  A speed ratio selection lever 24 operates in a door 50, such as for example a sliding track, comprising two branches 51 and 52 joined by a transverse track 53 extending between the end of the branch 52 and an intermediate portion. between the ends of the branch 51. The door 50 defines five positions: "R" at the end of the branch 52; "N" in an intermediate zone between the ends of the transverse track 53; "S" at the junction of the branch 51 with the transverse track 53; and "+" and "-" at the ends of the branch 51. In the branch 51, the lever 24 is biased towards the central position "S". The position "N" of the selector lever 24 corresponds to the neutral position; "R"

  corresponds to the selection of reverse gear; "S" corresponds to the selection

  a mode of operation; momentary movement of the lever to the "+" position produces a control which causes the gearbox to shift to the higher gear ratio; and a momentary movement of the lever

  from speed 24 to the "-" position produces a command to pro-

  the downshift of the gearbox and that of a gear ratio.

  The positions of the lever 24 are detected by a series of sensors, for example microswitches or optical sensors, arranged around the door 50. The signals from the sensors are sent to the electronic control unit 36. A signal of output delivered by the control unit 36 controls a gear engagement mechanism 25, which engages gear ratios of the gearbox 12, in accordance with the movement of the selection lever 24 by the driver of the vehicle. The gear commitment mechanism may comprise by

  examples of hydraulic pistons and electronic control valves

  magnetic means for moving selection elements for engagement and disengagement of different gear ratios, for example as

  this is described in the patent specification WO 97/05410 of the present

  applicant. In addition to the signals delivered by the speed or ratio selection lever 24, the control unit 36 receives the following signals:

  a signal from the sensor 19a and indicating the degree of

  the accelerator pedal 19; a signal from a sensor 30 and indicating the degree of opening of the throttle valve 18; a signal coming from the sensor 26 and indicating the speed of the motor; a signal coming from the sensor 42 and indicating the speed of the driven disk of the clutch; a signal coming from the sensor 34 and indicating the position of the slave cylinder of the clutch; and a signal from the sensor 32 and indicating the selected gear ratio. The control unit 36 uses signals from these sensors to control the actuation of the clutch 14 when starting from the stopped state and the gear changes, for example as

  this is described in patent specifications EP0038113, EP0043660,

EP0059035, EP0101220 and WO92 / 13208.

  In addition to the aforementioned sensors, the control unit 36 also receives signals from a non-blocking brake sensor system 52, an ignition switch 54 and a brake switch 56 associated with the main system. braking, for example the pedal

brake 58 of the vehicle.

  A vibrator 50 is connected to the control unit 36 to warn / indicate to the driver of the vehicle the appearance of certain conditions of

  operation. In addition to or in place of the vibrator 50, a blinking light

  Warning aunt or other indicator means may be used.

  A speed ratio indicator 60 is also provided to indicate the

gear ratio selected.

  With the system described above, when the vehicle is stopped, a start of the engine 10 under the effect of the actuation of the ignition switch 54, activates the transmission system and the control unit, and the control unit 36 brings the means

  38, 22, 20 for actuating the clutch to disengage the clutch 14.

  Moving the shift lever 24 from the neutral position "N" to the "S" operating position or to the "R" reverse position then causes the control unit 36 to actuate the mechanism 25. commitment of the report to respectively engage the gear ratio before the weakest (first gear) or the reverse gear. When depressing the accelerator pedal 19 to start the vehicle, the control unit 36 then causes the means 38, 22, 20 for actuating the clutch to reset the clutch 14, to start moving forward. The reclosing of the clutch 14 executed in this manner is controlled by the control unit 36, as described for example in EP0038113; EP0043660; EP0696341 or EP0735957, so as to ensure a smooth start of the forward. Starting at a high speed of the engine can also be obtained by depressing the accelerator pedal before the shift lever is moved from the neutral position "N" to the "S" position. "or the reverse position" R ". A reclosing of the clutch can then be controlled by the control unit 36, as described in EP0043660, EP0696341

or DE19911332.7.

  The high speed starting of the engine, performed in this manner, is used mainly when the transmission is under load, for example when the vehicle starts up hill or performs a

  towing, but also provides a quick start if required.

  Nevertheless, normal start-up procedures of the type described above can not be compared to sports driving starts or race starts that can be achieved with

  a manual transmission system.

  With the transmission system according to the present invention, a sporting or racing start can be triggered by depressing the brake pedal 58 and holding the shift lever 24 in the downshift position "-" for a predetermined period of time. typically 5 seconds, after moving the shift lever 24 from the neutral position "N" to the mode position of

walk "S".

  Once the predetermined period has ended, the control unit 36 activates the vibrator 50 'to provide an audible warning confirming that the sport start or race mode has been triggered. Typically the audible start has a duration of one second. After activation of the sports start or racing mode, the accelerator pedal of the vehicle can be depressed to increase the speed of the engine, without engaging the clutch 14. The vehicle can then start with a high speed of the engine, under the effect of the release of the shift lever 24. The brake 58 can be released at any

  moment after running sports start or race.

  In accordance with the present invention, the clutch 14 is disengaged and the first gear is engaged when the shift lever 24 is moved from the neutral position "N" to the operating mode position "S". However, the clutch 14 remains disengaged until the shift lever 24 is released from the downshift position "-". It is therefore possible to obtain a sports boot or race similar to that obtainable

with a manual transmission.

  During the release of the shift lever 24 from the "-" downshift position, the control means 26 control the clutch actuating means 38, 22, 20 to reset the clutch according to a profile. predefined so as to achieve optimum acceleration of the vehicle smoothly from the idle state, while avoiding excessive wear and overheating of the clutch 14 and a stall of the vehicle engine. To achieve this, the clutch 14 can be initially reset relatively quickly so as to reduce the engine speed to a predetermined value, thereby reducing the speed difference between the drive disc and the driven disc of the clutch. 14 and reduce wear and heat of this clutch. This also prevents runaway of the engine and also makes higher torque available for acceleration of the vehicle. The reclosing of the clutch 14 can be controlled later for the maintenance of a

  optimum acceleration, while the engine speed is maintained

  above a predetermined minimum value so as to avoid stalling

of the motor.

  In addition, the reclosing of the clutch can be controlled by the control means 36 to produce a positive torque traction control, in order to prevent wheel slippage. For this purpose wheel slip can be detected by the non-locking brake sensor system 52, for example when the speed of a driving wheel exceeds that of a non-driving wheel, by more than a predetermined value, so typical 50 rpm. The positive torque traction control performed in this manner may however require higher speed differences between the clutch plates 14, which leads to wear and tear.

warming up.

  FIG. 3 represents a typical plot of variation of the engine speed Ve and the speed Vdp of the driven plate of the clutch, as a function of time, and shows the initial reduction of the engine speed Va.

  following a start request by releasing the shift lever

  speed management 24 at the moment to and the speed of the engine Ve and the speed

  Vdp of the driven plateau when they meet.

  As shown in FIG. 2, the control unit 36 controls the position of the brake 58 and the shift lever 24 to determine whether a sports boot or a race start has been triggered or not. Upon depression of the accelerator 19, the control unit 36 then triggers a normal start procedure if the sport start or race has not been triggered; or triggers a sport boot mode or race procedure if said mode has been

sets off.

  According to another embodiment of the invention, in

  the engine 10 is powered by the exhaust gas turbocharger.

  when the brake 58 is actuated and the shift lever 24 is moved into the "-" downshift position, for

  start a sport start or race mode, the competition unit

  Mande 36 causes the clutch actuating means 38, 22, 20 to partially reset the clutch 14 to charge the engine 10 so that an increase in engine speed increases the turbocharger pressure. With this mode of operation, the brake 58 must be

  kept tight until start is desired.

  Partial reclosing of the clutch 14 in this manner can be controlled by the control unit 36 to produce a predetermined torque level. Otherwise, a pre-engagement of the clutch 14 is controlled by the control unit 36 to deliver a predetermined pressure of the turbocharger, using a pressure sensor and

  a closed loop control circuit.

  Various modifications can be made without departing from the scope of the invention, and for example, while in the previous embodiment use is made of hydraulic means for actuating the clutch actuating means and the gear engagement mechanism. hydraulic, pneumatic or electric actuators, for example electric motors or electromagnets, as described

  for example in DE19504847; WO97 / 10456 or DE19734023.

  The claims appended to this application

  are proposals for wording, without prejudice to obtaining continuing patent protection. Applicant reserves the right to claim other features or combinations of features

  which are hitherto only exhibited in the description and / or drawings.

  References used in subclaims

  other developments of the subject matter of the main claim on the basis of the characteristics specified in

  the respective subclaims; you do not have to

  consider as a renunciation of obtaining an autonomous protection of the object from the characteristics or combinations of characteristics of the

  under the relevant claims. Given that compared to the state of

  the technique on the priority date, the subclaims may constitute

  individual and autonomous inventions, the applicant reserves the right to

  right to use them as an object of independent claims or

  distinctive features. The objects of these subclaims may

  also constitute autonomous inventions which represent a

  independent configuration of the objects of the preceding subclaims.

  Exemplary embodiments should not be construed as limitations of the invention. On the contrary, in the context of this

  description, it is possible to use many variants and

  It changes, in particular variants, elements and combinations and / or

  materials, which, for example, by combination or modifications of

  ticks, elements or processes described individually in combination

  with the general description, examples of embodiments and

  drawings and claims, would be accepted by the specialists of this

  as a solution to the stated objectives and, by combining such characteristics, lead to a new object or to new process steps or to new sequences of process steps, also to the extent that they relate to manufacturing processes. ,

control and operation.

REVE N DICATIONS

  An automatic transmission system comprising a coupling as a main drive clutch (14), clutch operating means (22,38) for controlling the engagement state of the clutch, a multi-speed gearbox, a gear engagement mechanism for engaging an active ratio in the gearbox, a driving mode selector operable by a driver and allowing the driver to select the position neutral or a mode of operation, characterized in that it further comprises switching means for executing a start at a high speed and electronic control means for controlling the actuating means of the clutch, that the means of control are adapted to disengage the clutch for engaging a start speed when moving the operating mode selector from the neutral in a running mode, and for controlling, in a first mode, a re-engagement of the clutch as a function of the speed of the engine, that the control means also comprise means for detecting the actuation of a brake of the vehicle, and that, in a second mode, the means of are suitable for, when actuating the brake and the switching means, allow an increase in the speed of the engine without re-engagement of the clutch, the control means being adapted, in the second mode, to bring the means for actuating the clutch to re-engage

  the clutch, during the release of the switching means.

  An automatic transmission system according to claim 1, characterized in that the brake and the switching means are to be activated for a predetermined time interval before the second

mode is triggered.

  An automatic transmission system according to claim 2, characterized in that an audible and / or visual warning (50 ') is issued to

  the end of the predetermined time interval.

  4. Automatic transmission system according to any one of

  Claims 1 to 3, characterized in that the switching means

  include a speed selector of a semi-automatic transmission system

  automatic, a brake lock switch or a dedicated switch. 5. Automatic transmission system according to any one of

  claims i to 4, characterized in that, upon the release of the means

  switching, the clutch is re-engaged according to a predetermined profile. 6. Automatic transmission system according to claim 5, characterized in that during the release of the switching means, the clutch is initially re-engaged quickly to reduce the

  engine speed to a predetermined value.

  7. Automatic transmission system according to one or the other

  claims 5 and 6, characterized in that, upon the release of

  switching means, the clutch is re-engaged to maintain the

  motor speed above a predetermined minimum value.

  8. Automatic transmission system according to any one of

  Claims 5 to 7, characterized in that upon the release of the means

  switching, the clutch is re-engaged to prevent wheel slip. 9. Automatic transmission system according to any one of

  Claims 1 to 8, characterized in that when the brake is actuated

  and switching means, the clutch is partially pre-engaged

to charge the engine.