FR2767503A1 - DRIVE ARRANGEMENT FOR A MOTOR VEHICLE - Google Patents

Abstract

A motor vehicle drive arrangement comprises an engine (3) whose crankshaft (9) is connected via an automated clutch (11) to an output shaft (19) of an automated gearbox (17), and a control device (33) for controlling the engine torque (57) as well as the clutch (11), to which are sent the signals representing the rotational speeds of the crankshaft (9) and of the output shaft (19) and of the signals characterizing the driver's desire. When the clutch (11) fails in its closed state, the controller (33) controls the engine torque (57) to adjust the rotational speed (55) of the crankshaft (9) so that it corresponds to that (53) of the output shaft (19) at the desired speed ratio (64), which is engaged when passing below a predetermined differential rotational speed (52) between the crankshaft (9) ) and the output shaft (19).

Description

The invention relates to a drive arrangement of a vehicle

  automobile, comprising an engine whose crankshaft can be connected via an automatically actuated clutch to an output shaft of an automated actuated gearbox, and comprising at least one control device for controlling the engine torque as well as the automated actuation of the gearbox clutch, to which the signals representing at least the rotational speeds of the crankshaft and the output shaft of the gearbox are sent

  speeds as well as signals characterizing the driver's desire.

  Document DE 196 05 722 A 1 discloses a drive arrangement which comprises a motor whose engine torque is capable of being controlled by means of the position of the throttle adjustable by a servomotor. By means of a crankshaft capable of being engaged with an input shaft of the gearbox via an automatically actuated clutch, the engine torque is transmitted to the latter. The gearbox input shaft can be connected to a gearbox output shaft via an automated actuation gearbox. This gearbox output shaft is in action with the drive wheels via a differential. The adjuster associated with the throttle valve, the automated actuation clutch, and the automated actuation gearbox are controlled by a control device. To this control device are sent signals characterizing the operating state, coming from at least one rotation speed detector on the crankshaft, on the input shaft, and on the output shaft of the gearbox. speeds. In addition, an adjustment member provided for the automated actuation of the clutch and an actuator provided for the automated actuation of the gearbox are each provided with a detector, the signals of which are sent to the control device. In addition, signals characterizing the driver's desire are sent to the control device. The control device has a control circuit which checks the correct functioning of the automated actuation of

the clutch while driving.

  The disadvantage of this control device is that one can certainly recognize a defect in the automated actuation of the clutch, but that a drive is no longer ensured when the actuation

  clutch is defective.

  Document DE 27 42 033 Ai or document US 4,200,007 discloses a device for controlling synchronous operation of an unsynchronized gearbox. In the case of non-synchronized gearboxes, it is necessary to synchronize the parts to be connected of the gearbox in order to be able to engage a gear ratio. If deviations from synchronism have been provided for, the deviations must have a direction determined according to whether a change of speed ratio is to be made towards a higher gear or towards a lower gear. In addition, the differences

should be only minimal.

  The objective underlying the invention is to allow driving when the automated actuation of the clutch is defective and

that the clutch is closed.

  This objective is achieved in accordance with the invention described here.

  Thanks to the fact that in the event of a failure of the automated actuation of the clutch in the closed state of the latter, the control device controls the engine torque to regulate the speed of rotation at the crankshaft so that its speed of rotation corresponds to the speed of rotation of the output shaft of the gearbox according to the desired speed ratio, and the desired speed ratio is engaged when passing below a speed of rotation predetermined differential between the crankshaft and the output shaft, taking into account the gear ratio envisaged. Thanks to

  this, at least a restricted driving is ensured.

  For starting, the engine is started when the gearbox is in the idle position. The engine is firstly set to idle speed by the

  ordered. Then the engine speed is adjusted

  below the predetermined differential speed. A starting speed ratio is engaged and the speed of rotation of the output shaft of the gearbox is adapted to the speed of rotation of the crankshaft by means of a synchronization device provided in the gearbox. The differential speed must be determined so that the operation of the motor at this speed is also ensured during the engagement of the gear ratio. The predetermined differential rotational speed can also be given as a function of the gear ratio, so that a differential rotational speed is associated with each gear.

of speed.

  When changing the gear ratio, the engine torque is controlled by the control device to adapt the rotational speed of the crankshaft to the rotational speed of the input shaft of the gearbox, which corresponds to the ratio desired speed. When one goes below the predetermined differential speed of rotation, one controls the engagement of a gear ratio. A differential speed still present is eliminated in the gearbox by means of the synchronization device. By adapting the rotation speed of the crankshaft to the corresponding rotation speed of the gearbox output shaft, the synchronization members of the synchronization device in the

  gearbox are thus spared.

  It is also possible to associate a braking means with the crankshaft which is controlled by the control device to brake the crankshaft. Thanks to this, a change to switch to a gear ratio

  higher speed can be accelerated.

  This command ensures both starting and changing gear when the clutch is closed. For example, when a regulating member provided at the clutch for automatic actuation fails, one should only expect longer gear change times. Since a gear change is possible, the vehicle continues to operate over the full range of normal operation, with

  particular to all driving speeds.

  It has proven advantageous to control the engine torque in the direction of an absence of load in order to obtain an engaged gear ratio. When there is no load, the motor precisely supplies the torque which is applied on the output shaft side against the input shaft in the gearbox

  speeds due to the mass inertia of the motor vehicle.

  In the range of no load, the release of the gear ratio is possible with the application of a particularly low force. Provision can be made to pre-stress the gearbox in the direction of the idle position already during steering towards the absence of load. When the applied load drops below a limit value, the speed ratio jumps by the force of

prestressing which acts.

  Since in the case of this command, a gear change takes a little longer than in normal operation, it is advantageous to minimize the number of gear changes, by skipping at least one gear . Starting from the second gear, for example, a change is made to the fourth gear, from the third gear to the fifth gear or vice versa. It has proven advantageous to obtain a gear ratio engaged when passing below a minimum speed of rotation, to prevent the engine from stalling. The passage below the minimum speed may be caused by a reduction in the actuation of the accelerator pedal or by the actuation of the brake. It is also possible to provide for predetermining the minimum speed of rotation as a function of the functional parameters, such as actuation of the

brake pedal.

  It has proven to be advantageous to initiate a report of

  speed only after completion of the braking operation.

  During the braking operation, the engine idling speed is preferably controlled. After completion of the braking operation, the crankshaft can then be quickly accelerated, starting from the idle speed, to reach the speed, corresponding to the desired speed ratio, of the input shaft of the gearbox. Acceleration of the crankshaft to the desired rotational speed can easily be achieved with little work by means of the engine torque control. The deceleration of the crankshaft is not, however, as easy to influence, since friction losses are the cause of the deceleration. We will wait until the rotation speed of the crankshaft has dropped to the desired rotation speed. According to an advantageous embodiment, there is provided a control device provided with a starting function. Thanks to this starting function, a starting speed ratio is engaged when the vehicle is stationary. When the driver signals the desire to start, preferably by actuating the accelerator pedal,

  the engine is started which causes the vehicle to start.

  This starting function has the advantage that starting is possible even on hills. It is also possible without problem to use the second gear as the starting gear. When the control device has this starting function, it has proved advantageous to stop the engine when the vehicle is stopped and to already initiate a starting speed ratio so that starting is immediately possible when the

  signaling of a desire to start.

  The invention will be described in more detail in the following with reference to an exemplary embodiment. The figures show: Figure 1 a schematic illustration of a drive arrangement; Figure 2 a schematic illustration of the start function; Figure 3 a schematic illustration of a change of speed ratio to a higher speed ratio; Figure 4 a schematic illustration of a gear change to engage a lower gear; and FIG. 5 a schematic illustration of a stop operation in the event

an emergency function.

  The basic structure of the drive arrangement 1 is described with reference to FIG. 1. The drive arrangement 1 comprises a motor 3, a clutch 11, a gearbox 17 and a control device 33. The motor 3 is provided with a power adjustment member 5 in the form of a throttle valve 7 which is provided with a detector and which is controlled by the control device 33. The engine 3 comprises as a driven member a crankshaft 9 with which is associated a detector 37 for detecting the rotational speed of the crankshaft 9 and which can be connected via the clutch 11 to an input shaft 15 of the gearbox. The clutch 11 is provided with a servomotor 13 which is controlled by the control device 33. In addition, an actuator 21 associated with the gearbox 17 is controlled by the control device 33. Via an output shaft 19 of the gearbox with which a detector 39 is associated to detect the speed of rotation, the gearbox 17 is connected to a differential 23 with which the drive wheels 25 are in active connection. The drive arrangement 1 further comprises an accelerator pedal 27 and a brake pedal 29, the positions of which are detected by means of the detectors.

  43, 45 whose signals are sent to the control device 33.

  A manipulation element 30 for activating an emergency function 51 is produced in the form of a switching lever 31. The switching lever 31 is provided with a detector 41 for detecting the switching position, the signals of which are sent to the device 33. This switching lever 31 comprises a plurality of switching positions, a switching position being provided to activate the emergency function 51. It is also possible to provide a

  separate switch to activate the emergency function 51.

  The engagement of this switching position can be prevented by means of a cap and triggered only in the event of a fault

  recognized or when the driver deliberately chooses.

  In what follows, the operating mode 51 will be described in more detail with reference to an exemplary embodiment, by means of which at least restricted driving is possible during a failure of the automated actuation of the clutch 11. The failure or a defect in the automatic actuation of the clutch can be recognized by the control device 33 or also by the driver. For example, when the servomotor 13 for the automated actuation of the clutch 11 is controlled by the control device 33, but the signal indicating the positioning displacement of the servomotor 13 remains absent, it is assumed that the servomotor 13 has failed. In addition or alternatively, the absence of the desired positioning displacement can be recognized by means of the speeds of rotation of the crankshaft 9 and the input shaft 15 of the gearbox.

of speeds.

  In what follows, the mode of operation of the control device 33 will be described in more detail with reference to FIGS. 2 to 5, when a fault in the automated actuation of the clutch is

  recognized, which is designated in the following by backup function 51.

  The emergency function 51 comprises the three operating units

  that are starting, changing gear and stopping.

  We can also provide a restricted version with only two of these operating units. Firstly, the operating unit that is starting will be described in more detail with reference to FIG. 2. FIG. 2 shows a diagram in which the speeds of rotation of the output shaft 53 of the gearbox and crankshaft 55 over time, taking into account the gear ratios of engine torque 57, position 47 of the accelerator pedal, position 70 of the clutch and position 61 of the gearbox of speeds. When the driver signals the desire to drive by actuating the accelerator pedal 27, the vehicle being stopped and the engine 3 not turning, a starting speed ratio is engaged by the emergency function 51 by controlling the actuator 21, preferably the second gear ratio, provided

  that such a gear ratio is not yet engaged.

  For driving with the start function 77 or in the case of

  emergency function 51, it will be assumed that the clutch 69 is engaged.

  In the case of a hydraulic servomotor 13 for the automated actuation of the clutch 11, the clutch 11 closes automatically slowly due to the leaks which still exist

in hydraulic systems.

  In the case of mechanical systems for the automated actuation of the clutch 11, the force necessary to open the clutch 11 is preferably provided by means of a servomotor 13 driven by an electric motor. When the servomotor 13 is activated, the clutch is maintained in the open position 71. Thus, a closed position of the clutch can be ensured for example by decoupling the

clutch actuator 13 1 1.

  The engine 3 is driven by a starter, which causes the vehicle to start. When a predetermined speed of rotation of the crankshaft 9 is reached, at which level the assistance of the starter is no longer necessary, it is stopped. Then, the rotational speed of the crankshaft 55 continues to increase. When a minimum rotation speed, preferably the idling rotation speed, is reached, the power adjustment member is then adjusted in dependence on the position of the accelerator pedal, that is to say in driver's desire match. The start operation is

successfully completed.

  In the following, the operating unit that is the change in speed ratio of the emergency function 51 will be described with reference to FIGS. 3 and 4. FIG. 3 shows a change to shift into a higher speed ratio. high 65, and Figure 4 shows a change to a lower gear 67. We will first describe the gear change illustrated in Figure 3. When a predetermined rotation speed of the crankshaft 55 is exceeded, an operation of shifting into a higher speed ratio 65 is caused by the control device. Provision may be made to fix the predetermined speed ratio as a function of the other driving parameters, such as for example the position 47 of the accelerator pedal. Preferably, a speed ratio stage is skipped to minimize the number of speed ratio changes during emergency operation. A gear change from the second gear to the fourth gear is made. Motor 3 is driven all

  first so that the drive train is free of load.

  When the driver does not impose any engine torque 57 by actuating the accelerator pedal, there is first of all a piloting towards a higher power of the engine. Then, the power is reduced until reaching the point at which the absence of load 58 is established. During this piloting of the engine, the actuator 21 is put under prestress in the direction of the release of the gear ratio engaged to actuate the gearbox of speeds 17. When one reaches the absence of load 58 or that one has practically reached it, the speed ratio jumps. Depending on the speed and the predetermined speed ratio to be engaged, the synchronous speed 56 corresponding to the gear ratio envisaged is detected by the control device 33. When changing to a higher speed ratio 65, the speed of rotation of the crankshaft 55 must be reduced, in order to reach the synchronous speed of rotation 56. The power adjustment member 5 is controlled in correspondence by the control device 33, for example by the fact that the butterfly valve 7 is closed or that the ignition point is offset. When passing below a predetermined difference between the speed of rotation of the crankshaft 55 and the corresponding speed of rotation of the output shaft 53, the actuator 21 is controlled to engage a predetermined speed ratio. A difference still existing between the speed of rotation of the crankshaft 55 and the speed of rotation of the input shaft 53 of the gearbox is canceled by synchronization members provided in the gearbox when the actuator is piloted. 21 towards the gear ratio to be engaged. At the synchronism point 54, the gear ratio engages and the crankshaft is again firmly connected to the output shaft via the gearbox 17. The rotational speeds are again identical, taking into account the reduction ratio. The

  gear change 75 is complete.

  A change of speed ratio 75 from a higher speed ratio 65 to a lower speed ratio 67 is effected in a corresponding manner, as shown in FIG. 4. Thanks to the control device 33, the speed adjusting member motor power is controlled to apply a discharge from the drive train. For this purpose, it may be necessary to first of all briefly increase the engine torque 57 supplied by the engine 3. The gearbox 17 is prestressed in the direction of idling by means of the actuator 21. When the we have practically reached the absence of load 58, the speed ratio jumps. Thus, the connection between the crankshaft 9 or the input shaft 15 and the output shaft 19 is defeated. Thanks to the control device 33, the new gear ratio to be engaged is predetermined. To accelerate the crankshaft 9, the power adjustment member 7 is accelerated to ensure adjustment at the momentary synchronous speed of rotation 56 expected towards the driving speed. When passing below the predetermined differential rotational speed, the actuator 21 is controlled to engage the desired speed ratio. A still existing difference between the speeds of rotation is canceled in the synchronization members of the gearbox 17 and the envisaged speed ratio is engaged when the synchronous speed of rotation 54 is reached. The engine torque is then adjusted depending on the position of the pedal.

acceleration 59.

  The operating unit which is the stop is described in more detail with reference to FIG. 5. When the driver signals the desire to stop, for example by actuation of the brake pedal 29 and that one passes below a predetermined crankshaft speed of rotation 53 and / or below a predetermined circulation speed, or else a predetermined gradient 81 of the crankshaft is exceeded, the engine is stopped. When the actuation of the brake pedal 29 is stopped before the stopping of the vehicle 79 is practically reached, the engine is restarted automatically by the torque applied to the crankshaft due to the mass inertia of the vehicle. The speed of rotation of the crankshaft 55 is again accelerated in dependence on the position of the accelerator pedal 47 by controlling the engine torque 59

  corresponding to the position of the accelerator pedal.

  When the vehicle is braked to zero speed or almost zero, the engine 3 is stopped. To prepare for the following start-up desire, if necessary, a gear ratio is already engaged

  starting 66 by means of the actuator 21.

  List of references 1 drive arrangement 3 engine 5 power adjusting member 7 throttle valve 9 crankshaft 1 1 clutch 13 servomotor 15 gearbox input shaft 17 gearbox 19 gearbox output shaft 21 actuator 23 differential 25 driving wheels 27 accelerator pedal 29 brake pedal maneuvering element 31 switching lever 33 control device throttle sensor 37 crankshaft sensor 39 gearbox output shaft sensor 41 lever sensor switching 43 accelerator pedal sensor brake pedal sensor 47 accelerator pedal position 51 emergency function 52 differential rotation speed 53 rotation speed, gearbox output shaft 54 synchronous point rotation speed , crankshaft 56 predetermined synchronous speed 57 engine torque 58 no load 59 engine torque in operation the accelerator pedal 61 gearbox position 63 idle position 64 desired gear ratio 65 upper gear ratio 66 starting gear ratio 67 lower gear ratio 69 clutch in clutch position clutch position 71 clutch open 73 release of a gear ratio 74 engagement of a gear ratio change of gear ratio 77 start function 79 stop

Claims (8)

Claims   1. Drive arrangement of a motor vehicle, comprising an engine (3) whose crankshaft (9) is capable of being connected via a clutch (11) with automatic actuation to an output shaft (19) of a gearbox (17) with automatic actuation, and comprising at least one control device (33) for controlling the engine torque (57) as well as the automated actuation of the clutch (11) of the gearbox (17) , to which are sent the signals representing at least the rotational speeds of the crankshaft (9) and the output shaft (19) of the gearbox (17) as well as signals characterizing the desire of the driver, characterized in that in the event of a failure of the automatic actuation of the clutch (1 1) in the closed state of the latter, the control device (33) controls the engine torque (57) to adjust the rotation speed to the level of the crankshaft (9) so that its speed of rotation (55) corresponds to the speed rotation shaft (53) of the output shaft (19) of the gearbox for the desired gear ratio (64), the selected gear ratio (64) being engaged when passing over a predetermined differential rotational speed (52) between the   crankshaft (9) and the output shaft (19).   2. Drive arrangement according to claim 1, characterized in that to release a speed ratio, the control device (33) controls the engine torque (57) towards the absence of load (58) for which the engine torque (57) is equal to the torque applied to the output shaft side of the gearbox due to the mass inertia of the vehicle, a gear ratio (73) being provided when the we go below a predetermined gap   compared to the absence of charge (58).   3. Drive arrangement according to claim 2, characterized in that the control device (33) controls the automated actuation of the gearbox (17) to release the past gear ratio, already when driving towards the no load, towards the   idle position (63), ensuring prestress.   4. Drive arrangement according to claim 1, characterized in that during a change of speed ratio (75), the control device (33) determines as desired speed ratio (64) a speed ratio greater than neighboring gear ratio. 5. Drive arrangement according to claim 1, characterized in that when the rotation speed (55) of the crankshaft leaves a predetermined rotation speed range, the control device   (33) causes a release of the engaged gear ratio (73).   6. Drive arrangement according to either of the claims   1 and 5, characterized in that when the brake pedal is actuated and the position of the gearbox is in the idle position (63), the control device (33) causes the engagement of a gear ratio (74) after completion of the braking operation when passing below a predetermined threshold value of the actuation of the brake pedal.   7. Drive arrangement according to claim 1, characterized in that the control device (33) comprises a starting function (77) which ensures by starting the engine (3) a starting of the vehicle when a gear ratio gear is engaged and a desire to start is signaled, in particular by actuation of the accelerator pedal (27).   8. Drive arrangement according to claim 7, characterized in that the control device (33) stops the engine (3) and engages a starting speed ratio when passing below a minimum regime.