DE19744051A1 - Motor vehicle with manually-operated gearbox and automatically-operated clutch - Google Patents

Abstract

A car has an automated clutch and manual gear-shifting. A sensor detects a gear shift and sends a representative signal to a control unit. The control unit determines the engine torque. Another sensor determines the position of the gas pedal. The control unit finally generates a signal for the clutch actuator. The control signal is generated when the engine torque is below certain threshold during a gear shift, this threshold being varied between limits according to a particular parameter like the rate of change of gas pedal position. When the gas pedal is released, the threshold is increased. During a positive rate of change of gas pedal position it remains unaltered but it is increased for a negative rate of change.

Description

The invention relates to a motor vehicle with an engine, a transmission and an automated torque transmission system such as Coupling, in which the gear ratio by means of an operating element tes, such as shift lever, is manually selectable, with a sensor device detects a manual actuation of the control element and a forwards a signal representing an actuation to a control unit which Control unit stands with sensors and possibly others Electronic units in signal connection, the control unit Engine torque determined and a sensor a load lever position Load control, such as accelerator pedal, detects the control unit from at least one Signal a parameter of a driver's actuation of an element determined and a control signal can be generated by the control unit, whereupon the torque transmission system when the Control element is disengaged by means of an actuator.  

For vehicles with an automated torque transmission system, such as Clutch, ensures the closed clutch in the drivetrain when engaged Gear for power transmission from the engine to the transmission and to the downstream drivable wheels. If the driver changes one Gear ratio is initiated, as is done by means of the control element the clutch must be disengaged.

When the control element is actuated, a sensor detects one Actuation and forwards a signal representing an actuation to the Control unit. The control unit can be based on a detected Disengage the clutch. This disengagement can occur in one unintentional actuation of the control element when the contact is high Engine torque lead to an uncomfortable engine start-up. In such Motor vehicles have become known according to US-PS 5099969 that a Driver's desired switching process by pressing the Control element is only permitted if when pressing the Control element the engine torque is below a limit. If the engine torque is above a limit, the shifting process prevented and the clutch is not disengaged.

However, this can be disadvantageous if the shifting is fast should be switched, although the engine torque is not yet below the Limit has dropped. Even with fast gear changes with one  Rapid release of the load lever can occur due to inertia System and internal time constants, the engine torque is not arbitrarily fast drop below the limit, although the driver is pressing the Shift levers usually coincide with the relief of the load lever, such as Accelerator pedals, starts or performs.

The object of the invention is to provide a motor vehicle in which an automated torque transmission system fast shifting operations can be carried out and the disadvantages of the prior art Technology can be reduced or eliminated. In particular, a switching process depending on the driver's actuation, for example Control element for gear change and / or load lever are allowed or be prevented.

The present invention is also based on the object Motor vehicle with automated torque transmission system too create in which the gear stages of the gearbox are safe and functional in essentially all relevant operating situations can be switched.

This is achieved according to the invention in that the control signal is generated is when the engine torque is one when the control element is actuated  predeterminable limit value falls below, the value of the predeterminable Limit can be changed depending on at least one parameter.

It can be expedient according to the invention if the predefinable limit value depending on the rate of change dα / dt of a parameter α is changeable.

It can also be advantageous if the specifiable limit value is as Function of a parameter, such as the rate of change of the Load lever position, is changeable.

Furthermore, it can be advantageous if the predefinable limit value is within predefinable barriers is changeable.

It is also advantageous if the predefinable limit value is at a driver-side withdrawal of the load lever position, as with a driver-side Release of the load lever as a function of the rate of change of one Parameter is increased.

It may also be useful if the Load lever position, as with a driver release of the load lever, the Predefinable limit value as a function of the rate of change Load lever position is increased.  

It is expedient if the predefinable limit value as a function of a negative rate of change of a parameter is increased.

It is also advantageous if the predefinable limit value is at a positive rate of change of a parameter remains unchanged.

According to a further aspect of the invention, it is useful if at a driver's actuation of the load lever, as with a driver's side Increasing the load lever position, the predefinable limit as a function of Rate of change of a parameter, such as the load lever position, is reduced.

According to the invention, it can be advantageous if the predefinable limit value is reduced with a positive rate of change of a parameter.

It can also be expedient if the predefinable limit value M _limits for the engine torque

M _limit = M ₀ - k * dα / dt

is changed, with an initial value M _{0 of} the predefinable limit value, a constant k and the rate of change dα / dt of a parameter α.

Furthermore, it can be expedient if the predefinable limit value M _limits for the engine torque

M _limit - M ₀ - k (α, dα / dt, ...) * dα / dt

is changeable, with an initial value M _{0 of} the predefinable limit value, a function k (α, dα / dt, ...) and the rate of change dα / dt of a parameter α, the variable k (...) being a function of α, dα / dt and / or of possibly other quantities, such as the time t.

Similarly, it may be expedient if the predeterminable limit value for an increase or reduction in dependence on a characteristic variable as a function of time is again returned to a predefinable setpoint value M _0th

Furthermore, it is expedient if the predefinable limit value is increased again to a predefinable target value M ₀ after an increase or reduction depending on a parameter as a function of time with a predefinable time delay.

It is also advantageous if a parameter is, for example, a Load lever position, throttle position, injection time and / or is an injection quantity.  

After another thought, it may be beneficial if instead of Engine torque monitors a variable representing the engine torque and if this value falls below a limit at a Actuation of the control element, the clutch is disengaged.

Furthermore, the invention relates to a method for controlling a automated torque transmission system in use for example inside a motor vehicle.

The invention is explained in more detail with reference to the figure . It shows:

Fig. 1 is a schematic representation of a vehicle,

Fig. 2 is a block diagram,

Fig. 3 is a diagram,

Fig. 4 is a diagram and

Fig. 5 is a block diagram.

Fig. 1 shows a vehicle 1 in a schematic representation, with a motor 2 as drive unit, a torque transmission system 3, such as clutch, and a transmission 4. The transmission 4 is followed by a drive shaft 5 and a differential 6 and the driven axles 7 a and 7 b, the wheels 8 a, 8 b being driven by means of the driven axles 7 a and 7 b. The vehicle can, for example, be provided with a switchable four-wheel drive. However, this is not shown in FIG. 1.

The torque transmission system 3 , such as friction clutch, magnetic particle clutch or torque converter with lockup clutch is shown in Fig. 1 as a torque transmission system 3 in the drive train between the engine 2 and transmission 4 , wherein the torque transmission system 3 can also be arranged on the output side after the transmission 4 , such as this can be useful, for example, in the case of continuously variable partial transmissions (CVT).

The torque transmission system 3 in the illustration of FIG. 1 consists of a clutch disc with friction linings 3 b, a pressure plate 3 c and a clutch cover 3 d and a plate spring 3 e. These parts of the torque transmission system can be mounted on a flywheel 3 a, which may be assembled with the flywheel 3 a as a pre-assembled unit. The flywheel 3 a can also be a so-called two-mass flywheel, which provides a torsional damper between the primary and secondary mass. The diaphragm spring 3 e by means of the release bearing 3 f for engaging or disengaging the clutch acted upon, said gene by the application of Tellerfederzun by means of the release bearing 3, the clutch f are converted into a state may or may be set, which for example, the fully engaged or is the fully disengaged state or a state between these two limit states. As a result, the torque that can be transmitted by the torque transmission system 3 can be set and fixed as desired in the range between zero and the maximum value.

The release bearing 3 f is actuated in the exemplary embodiment of FIG. 1 by means of a release lever 9 , the release lever being actuated over a hydraulic route with slave cylinder 10 , hydraulic line 11 and actuator 1 2. The actuator 12 contains an actuating device 12 a, which contains a master cylinder and a drive unit for actuating the master cylinder if a hydraulic path is used. Furthermore, the actuator 12 contains an electronic device 12 b, such as a control unit, which receives the incoming signals from, for example, sensor devices, sensors or other electronic units, stores them, retrieves and / or processes them from memories, and generates control signals to control the actuator, so that the torque transmission system is engaged or disengaged.

The transmission 4 is a transmission in which a differentiation can be made between different transmission ratios, such as gears, by means of an operating element 13 . To select a gear ratio from a plurality of gear ratios, the operating element 13 is brought into the position provided for this purpose or is actuated in a manner provided for this purpose. This operation can be done manually or automatically. The control element for manual, driver-side actuation can be designed as a shift lever or as an electronic element.

The device for disengaging the torque transmission system can as shown above, by means of a pressure medium system, the Hydraulic system, a pneumatic system or a pressure medium system other fluid operated system. The releaser can in these cases also be a pressure-operated central release. Furthermore, the Actuation also take place via mechanical means, for example electromotive via a linkage.

A sensor device 14 can be articulated or arranged on the control element 13 , whereby an actuation of the control element by this sensor unit 14 is detected. An actuation can be detected by measuring a force acting on the control element or by measuring a position, change in position or a speed or acceleration. Furthermore, the actuation can be detected when a limit or threshold value is exceeded when the operating element is moved or actuated.

The sensor or the sensor device 14 can be a displacement or speed-dependent or acceleration-dependent or force-dependent sensor, which can detect or detect a movement of the operating element or an element connected to it or a force on the operating element or on an element connected to it.

Furthermore, a sensor 15 can be arranged on the transmission 4 , which detects the position of the gear engaged by, for example, sensing the position of shift elements inside the transmission.

The sensors, such as throttle valve sensor 16 , such as wheel speed or speed sensor 17 (vehicle speed sensor), engine speed sensor 18 and further sensors can be provided in / on the vehicle and connected to the control unit via signal lines. A door sensor, which detects whether a door is open, can also be arranged on the vehicle.

The control unit can determine characteristic quantities from the data of the sensors, these characteristic quantities being the sensor signals themselves or quantities or signals derived or processed by them, such as calculating a rate of change of characteristic quantities or sensor signals such as gradients, which are used to evaluate a driver's intention to switch can be. These rates of change or gradients can be calculated, for example, by numerical methods, such as by difference quotients. The control unit 12 determines the driving state from these sensor data and other data as well as from system input variables and generates a control signal for actuating the torque transmission system 3 if an intention to shift is assessed as being present.

Sensor signals or derived or processed from them are used as parameters Signals used, such as the load lever position, the Rate of change of the load lever position and / or other processed or filtered signals. The parameter thus represents a size for one represents driver-side actuation of an actuating element Rate of change of the load lever position is therefore a parameter for the driver's accelerator pedal actuation.

If the control element of the transmission is actuated by the driver, the control unit and the actuator disengage the torque transmission system by generating a control signal for opening the torque transmission system. However, this generally only takes place if the calculated or determined engine torque is less than or equal to a predefinable limit value M _{limit of} the engine torque. May further include a driver-side shift intention to suppress or evaluated as not given, when the determined engine torque exceeds the limit value M _limit.

The motor vehicle 1 also has an accelerator pedal 20 , such as a load lever, and an actuating element of a brake 21 , such as a service brake, and an actuating element 22 for a brake, such as a parking brake. At least one sensor 23 is arranged on the load lever 20 and determines the position or the actuation α of the load lever. This also makes it possible to determine whether there is an existing or non-existent actuation. As a sensor for determining whether the pedal or the load lever is actuated or not, an idle switch can also be used, which is switched on when the pedal is not actuated and which is switched off when the pedal is actuated. This idle switch can be replaced electronically by the actuation determined by the sensor, in which an actuation bit can be set if the sensor 23 detects a non-disappearing actuation.

A brake switch 24 , which detects whether the brake is actuated, can be arranged on the actuating element of the service brake 21 , such as the brake pedal. Such a brake switch can also be arranged on the actuating element 22 for the parking brake, the sensor 25 detecting whether the parking brake is actuated.

The sensor device 23 of the load lever 20 is signal-connected to engine electronics 30 , so that the engine speed and the engine torque are controlled by the engine electronics 30 according to predetermined methods via an accelerator pedal actuation or load lever actuation.

The applied engine torque can be determined on the basis of the signals arriving in the control unit 12 , such as measurement data or system input variables. The applied engine torque is the current engine torque minus / plus the moments that are picked up or given off by auxiliary units. As an auxiliary unit, for example, the air conditioning system or a swing useful storage unit may be mentioned. Drag torques can also be taken into account.

Furthermore, it can be determined whether the control element 13 is actuated and it can be determined whether a brake 21 , 22 is actuated and whether the accelerator pedal, such as the load lever, is actuated. The control unit 12 recognizes an intention to switch by actuating the operating element 13 on the basis of the incoming signals from the sensors 14 and / or 15 . The system parameters determine whether the shift intention is evaluated or accepted by the control unit as a shift request and whether a control signal is generated to open the clutch.

For example, it is not appropriate in every situation that a switch Intent signal is also evaluated so that there is a switching operation. In is usually used as a condition for a desired gear change or for taking out a gear provided that the engine torque is smaller is a predetermined limit and / or that the actuation of the load lever is less than a predefinable limit value, that is to say, for example, that the The load lever is not actuated and the idle switch signals this.

If the control unit 12 uses its input signals, such as sensor values and other signals, to determine whether the control element has been actuated by the driver, such as the intention to shift, this is first checked before the clutch is disengaged in a controlled or regulated manner.

It is expedient if the control unit prevents the intention to switch if the engine torque exceeds a certain limit, the limit value being variable depending on at least one parameter is. The engine torque determined for this minus, for example, drag Moments and moments due to secondary consumers is considered by the Control unit compared with a predetermined limit and in the case of If the engine torque is exceeded above the limit value, a switching will occur Intentionally considered inadmissible and the torque transmission system will not be disengaged. This is to prevent false triggers because of that  it is assumed that the driver does not want to shift while turning on Moment (performance) demands.

Is at the driver's side quickly carried out switching operations, in which the operating element 13 rapidly operated and the load lever 20 is driver-released relatively quickly or is withdrawn, it may under certain circumstances happen that the engine torque M _mot is not fast enough below the limit value M _limit may decrease and thereupon the control unit 12 evaluates the intention to shift as not being present and the clutch does not disengage, although the driver deliberately initiates a shifting process by actuating the control element.

The cause of a non-instantaneous reduction in the engine torque M _mot when the load lever is withdrawn is, for example, the inertia of the rotating masses of the engine. Furthermore, it takes a certain time until the driver has reduced the load lever at least to such an extent that the resulting engine torque is below the predefinable limit value. This takes a certain amount of time, even if the engine electronics and the engine could react immediately.

The engine torque is calculated from the position or Position of the load lever or from the resulting Throttle valve position and / or the injection time or quantity. It reacts  however with a certain time delay on the input signal. So the driver reduces the throttle valve angle to zero by one To prepare the circuit, it takes a certain amount of time before that Motor torque reduced below the limit mentioned above. While During this time, the clutch is not opened and a shift is made at least disabled.

The driver usually starts operating the control element in the essentially at the same time as the reduction of the load lever. Thus the It is difficult to start the actuation movement because the clutch is closed or indented.

FIG. 2 shows a block circuit diagram 100 , in which the driver's actuation or withdrawal of a load lever or another element is indicated in block 101 . This withdrawal signal is delayed in block 102 by system-related dead times before a reaction can take place on the part of the engine electronics or the engine. The engine torque is calculated in block 103 and also takes time. Furthermore, inertia of the engine must be overcome before the desired engine torque requested by the driver is output in block 104 .

Fig. 3 shows a diagram 200 in which the load lever position 201, a shift lever operation signal 202, an engine torque 203, and a limit value for the engine torque 204 as a function of time are shown. At time t ₀ , 205, the load lever is withdrawn on the driver side or the actuation is reduced, and essentially the operator control element of the transmission for shifting the gears is actuated on the driver side, as can be seen from the reduction in signals 201 and 202 from time 205 . The engine torque 203 is essentially constant until time 207 and is reduced from time 207 . The time difference between time 205 and time 207 results, for example, from inertia and dead times.

The engine torque is below the limit value 204 for the engine torque from the point in time t ₁ , 206 and from this point in time a shift is considered to be present. At this point in time, however, the control element has already been actuated almost completely due to, for example, a fast switching speed, although the clutch was previously closed. In this example it becomes clear that an increase in the limit value to, for example, the value 208 would be advantageous.

FIG. 4 shows a diagram 300 in which a load lever position 301 or a quantity equivalent to this is shown as a function of time t.

The limit value 302 , MG _limit for the engine torque is also shown as a function of time. The value is at low load lever change speeds at the value M ₀ , and at high load lever change speeds the value of M _{limit increases} based on curve 302 a. At maximum load lever change speeds, curve 302 a reaches its maximum. If the load lever is essentially zero, the increased value of M _{limit is} reduced again to the value M ₀ . Curves 303 and 304 show a course of M _limits during the reduction. Curve 303 corresponds to a normal reduction and curve 304 shows a course of a reduction in which a filter function brings about a time delay.

As already shown above, an intention to switch is detected by means of at least one sensor which detects the movement of a Control element and / or the position of a control element and / or the Speed and / or acceleration of an operating element dedicated. Furthermore, such a sensor can also exert a force on the Detect control element directly or indirectly. Using a Displacement sensor in the area of the control element and a displacement sensor in the Range of internal shifting elements can exist in the presence of Elasticities in the force path between the control element and the transmission-internal switching elements also a differential path measurement occur around a force-proportional or force-representative signal  received, which are used to evaluate a switching intention can.

The shift intention signal, as has been described so far, is a digital one Signal, that is, there is an intention to switch, or it is considered not evaluated in the present case or not available. Furthermore, that Switching intention signal as a continuous signal with values between one Minimum value and a maximum value determined or calculated and processed will. Even before the signal is reached, exceeded or undershot with regard to a trigger threshold or a predefinable limit at Triggering a shift intention, the clutch torque can be reduced. With a slight actuation, the clutch is below the Switching intention threshold already slightly opened, so that the reaction to a shift intention signal corresponding to the operating speed of the Control element can be adjusted by the driver.

The transition from "slowly opening" the torque transmission system for "rapid tearing open" of the torque transmission system would then be depending on the type of driver's operation of the Control element continuously. Also in the timing of the opening at a circuit would have a continuous transition.  

A slight opening of the clutch should fall below one first limit value take place, with a complete opening of the clutch would only take place if the value falls below a second limit.

In this operating state, a brief slip phase before opening of the torque transmission system occur during the drivetrain is de-energized so that the build-up of an oscillation of the Gearbox input side is thereby counteracted. This means that a at least slight opening of the torque transmission system a detected movement of the control element is already controlled, although the predefinable threshold value for recognizing a switching intention has not yet been exceeded. The amount of this is at least marginal Opening can depend on filtered or processed signal values be selected, with the typical vibrations of the shift lever should be disregarded.

FIG. 5 shows a block diagram 400 for explaining the method according to the invention when used within the motor vehicle according to the invention. The method is started in block 400 . In block 402 , a query is made as to whether the control element has been actuated by the driver. If this is the case, the process continues in block 403 ; if this is not the case, the method for this time step or this interval is ended in block 408 .

The engine torque is determined or ascertained in block 403 , wherein the engine torque can be determined from system input variables or can be obtained, for example, from another electronic unit via a signal line or a data bus.

In block 404 , the load lever position α or a variable representing it or an equivalent variable is determined. Furthermore, the rate of change or the gradient of this variable is determined or calculated. If necessary, these variables can also be obtained from another electronic unit via a signal line or a data bus.

In block 405 , the limit value for the engine torque or a variable representing this is determined, this preferably according to

M _limit = M ₀ - k (α, dα / dt, ...) * dα / dt

is determined, where M _{0 is} an initial value, k is a variable, which may depend on α, dα / dt, or other quantities, and α is a quantity that at least represents the load lever position, and dα / dt is the rate of change of this quantity. k can be a linear, non-linear or any function of the parameters or be a constant.

In block 406 , it is determined whether the engine torque M _{mot is} less than this specific limit value M _limit . If this is the case, the clutch is disengaged by the control unit by means of the actuator in block 407 before the method is ended in block 408 .

This process can be repeated cyclically with a predeterminable clock rate will.

The claims submitted with the application are drafted strikes without prejudice for obtaining further patent protection. The The applicant reserves the right to do so, so far only in the description and / or to claim disclosed features.

Relationships used in subclaims point to the others Training the subject of the main claim by the features of respective subclaim; they are not a waiver of education development of an independent, objective protection for the characteristics of the to understand related subclaims.

However, the subjects of these subclaims also form independent ones Inventions that are one of the items of the previous sub have independent design.

The invention is also not based on the embodiment (s) of the Be limited writing. Rather, numerous Ab are within the scope of the invention  Changes and modifications possible, especially such variants, Elements and combinations and / or materials, for example, by Combination or modification of individual in connection with that in the general description and embodiments as well as the claims described features and elements contained in the drawings ten or process steps are inventive and can be combined Characteristics of a new item or new procedural steps or process step sequences, also in so far as they are manufacturing, testing and Concern working procedures.

Claims (17)

1. Motor vehicle with a motor, a transmission and an automated torque transmission system, such as a clutch, in which the gear ratio can be selected manually by means of an operating element, such as a shift lever, a sensor device detecting a manual actuation of the operating element and a signal representing an actuation forwards a control unit, the control unit is in signal connection with sensors and possibly other electronic units, the control unit determining the engine torque and a sensor detecting a load lever position of a load lever, such as the accelerator pedal, the control unit determining a parameter of a driver's actuation of an element from at least one signal and A control signal can be generated by the control unit, whereupon the torque transmission system is disengaged when the control element is actuated by means of an actuator, characterized in that the control signal is generated when, when the control element is actuated, the engine torque falls below a predefinable limit value, the value of the predefinable limit value being changeable as a function of at least one parameter. 2. Motor vehicle according to claim 1, characterized in that the Predefinable limit value depending on the rate of change dα / dt of a parameter α can be changed. 3. Motor vehicle according to claim 1, characterized in that the Predefinable limit as a function of the parameter, such as the Rate of change of the load lever position is changeable. 4. Motor vehicle according to one of claims 1 to 3, characterized characterized in that the predefinable limit within predeterminable Barriers is changeable. 5. Motor vehicle according to one of claims 1 to 3, characterized characterized in that the predefinable limit for a driver Withdrawal of the load lever position, as with a driver release of the load lever, as a function of the rate of change of one Parameter is increased.   6. Motor vehicle according to one of claims 1 to 3, characterized characterized in that when the load lever position is withdrawn, as in a driver-side release of the load lever, the predefinable limit increased as a function of the rate of change of the load lever position becomes. 7. Motor vehicle according to one of claims 1 to 3, characterized characterized in that the predefinable limit as a function of a negative rate of change of a parameter is increased. 8. Motor vehicle according to one of claims 1 to 3, characterized characterized in that the predeterminable limit value with a positive The rate of change of a parameter remains unchanged. 9. Motor vehicle according to claim 3, characterized in that at one driver's actuation of the load lever, as with a driver's side Increasing the load lever position, the specifiable limit as a function the rate of change of a parameter, such as the Load lever position is reduced. 10. Motor vehicle according to one of claims 1 to 3, characterized characterized in that the predeterminable limit value with a positive Speed of change of a parameter is reduced.   11. Motor vehicle according to one of claims 1 to 3, characterized in that the predetermined limit value M _limit for the engine torque after
M _limit = M ₀ - k * dα / dt
is changed, with an initial value M _{0 of} the predefinable limit value, a constant k and the rate of change dα / dt of a parameter α. 12. Motor vehicle according to one of claims 1 to 3, characterized in that the predeterminable limit value M _limit for the engine torque after
M _limit = M ₀ - k (α, dα / dt, ...) * dα / dt
is changed, with an initial value M _{0 of} the predefinable limit value, a function k (α, dα / dt,...) and the rate of change dα / dt of a parameter α. 13. Motor vehicle according to one of the preceding claims, characterized in that the predefinable limit value after an increase or reduction depending on a parameter as a function of time is returned to a predefinable setpoint M ₀ . 14. Motor vehicle according to one of the preceding claims, characterized in that the predefinable limit value after an increase or reduction depending on a parameter as a function of time with a predeterminable time delay, such as filtering, is returned to a predefinable setpoint M ₀ . 15. Motor vehicle according to one of the preceding claims, characterized characterized in that a parameter, for example Load lever position, throttle position, injection time and / or an injection quantity. 16. Motor vehicle in modification of the preceding claims, characterized characterized in that the engine torque instead of the engine torque representative size is monitored and if this is undershot Size below a limit when the control element is actuated the clutch is disengaged. 17. Method for controlling an automated Torque transmission system in use within one Motor vehicle in particular according to one of the preceding Expectations.