DE102018001728A1 - Method and system for controlling the transmission of torque in a vehicle - Google Patents

Abstract

The present invention relates to a method for controlling the transmission of torque in a vehicle (100), the vehicle (100) comprising: a powertrain for transmitting torque between a drive power source (101) and at least one drive wheel of the vehicle (101) A driver actuating means (118) wherein a torque to be transmitted by the drive train is controllable in response to an electrical signal representative of a position of the driver actuating means (118), the method comprising: - detecting whether a change in the of Powertrain torque to be transmitted by the driver actuating means (118) is requested, - Predicting a torque which is expected to be generated in the drive train when the change of torque transmission required by the driver actuating means (118) is controlled, and - affecting the change of Powertrain torque transmission based on this prediction age.

Description

Field of the invention

The present invention relates to vehicles, and more particularly to a method and system for controlling torque transmission in a vehicle. The present invention further relates to a vehicle, as well as a computer program and a computer-readable medium, which implement the method according to the invention.

General state of the art

There are different types of vehicle transmissions. For example, vehicle transmissions may be fully automatic, with a vehicle controller controlling the shifts. The transmissions used in these systems may consist of automated manual transmissions in which the vehicle controller automatically controls gear shifting in "manual" transmissions.

There are also manual transmissions where the driver has control over the shift. Gear change in manual transmissions is often accomplished by using a driver controllable clutch, often by using a clutch pedal. Automatic clutches can also be used in automated manual transmissions, in which case the clutch actuation during gear changes is controlled by the vehicle control and not by the driver. There are also systems with automated manual transmissions in which a controllable by the driver means, such as a clutch pedal, is present and can be used when starting the vehicle from a standstill. After the vehicle has been set in motion, subsequent gear changes may be arranged to be fully controlled by the vehicle controller without driver intervention and without further actuation of the clutch, i. Gear changes are carried out with the drive train closed. In this case, therefore, the clutch is completely controlled by the driver using a clutch pedal that is directly (mechanically) connected to the clutch servomechanism.

The present description relates to systems in which a driver actuating means, such as a clutch pedal or an accelerator pedal, is used to control torque transmission in a drivetrain, e.g. by controlling torque transmitting means, such as a clutch or other torque transmitting means, or a driving force provided by a driving force source. With respect to the torque transmitting means, the torque transmitting means are not controlled directly using a mechanical or hydraulic connection. Instead, e.g. Controlled torque transmission through the use of clutch-by-wire (CBW) systems. In clutch-by-wire systems, an electrical signal, e.g. represents a clutch pedal position, in a corresponding request for torque transmission, e.g. a corresponding coupling movement, implemented. For example, a position sensor or other suitable means may be used to detect a position of the driver actuating means, such as a driver. the position of a clutch pedal to recognize. An electrical signal representing this position is then translated into a corresponding driver request, e.g. for clutch operation, implemented, and the vehicle control controls e.g. the actual coupling movement as a function of the signal representing the position of the clutch pedal. The actual coupling movement is therefore not mechanically connected to the movements of the driver actuating means.

Systems of this type can offer advantages in the operation of the vehicle.

Brief description of the invention

It would be advantageous to achieve a method and system that reduces the risk of excessive loading of the powertrain in situations where the driver engages torque transmission between a driving power source and the drive wheels of the vehicle by controlling the torque transmitting means using a driver actuating means. To better address this concern, there is provided a method and system having the features defined in the independent claims.

• einen Antriebsstrang zum Übertragen von Drehmoment zwischen einer Antriebskraftquelle und mindestens einem Antriebsrad des Fahrzeugs, und
• ein Fahrer-Betätigungsmittel, wobei ein durch den Antriebsstrang zu übertragendes Drehmoment in Abhängigkeit von einem elektrischen Signal, das eine Position des Fahrer-Betätigungsmittels darstellt, steuerbar ist,

wobei das Verfahren umfasst:

• - Erkennen, ob eine Änderung des vom Antriebsstrang zu übertragenden Drehmoments durch das Fahrer-Betätigungsmittel angefordert wird,
• - Vorhersagen eines Drehmoments, das voraussichtlich in dem Antriebsstrang erzeugt wird, wenn die vom Fahrer-Betätigungsmittel geforderte Änderung der Drehmomentübertragung gesteuert wird, und
• - Beeinflussen der Änderung der Drehmomentübertragung des Antriebsstrangs basierend dieser Vorhersage.

The present invention relates to a method for controlling the transmission of torque in a vehicle,
the vehicle comprising:

• a drive train for transmitting torque between a drive power source and at least one drive wheel of the vehicle, and
• a driver actuating means, wherein a torque to be transmitted by the drive train is controllable in response to an electrical signal representing a position of the driver actuating means,

the method comprising:

• - Detecting whether a change in torque to be transmitted by the driveline is requested by the driver actuating means,
• Predicting a torque which is likely to be generated in the drive train when the change of torque transmission required by the driver actuating means is controlled, and
• - Affecting the change of the powertrain torque transmission based on this prediction.

There are various types of transmission systems in which a gear change can be manual or automatic. The transmission systems, whether manual or automatic, may include a clutch or other torque transmitting means for selectively disengaging torque transmission through the driveline, i. can be interrupted. Such systems may further include driver actuation means to enable the driver to actuate the torque transmitting means. Thus, e.g. In addition to an accelerator pedal and a brake pedal another pedal can be used. Such driver actuating means for controlling torque transmission means may also be present in hybrid vehicles.

The torque transmitting means may be controlled by the driver actuating means, wherein a signal, e.g. an electrical signal may be used to determine a position of the driver actuating means, such as a driver. A clutch pedal position, wherein the vehicle controller then controls the torque transmitting means based on the position signals.

The torque transmitting means may be further engaged from the disengaged state. When the torque transmission is disengaged, there is an interruption in the transmission of torque between the drive power source and the transmission. The transmission of the torque can be initiated by engaging the torque transmitting means. When the torque transmitting means is engaged from a disengaged state where torque transmission is interrupted, torque transmission in the driveline may increase from substantially zero to a higher level in some situations. The amount of torque that will be generated after engagement in the driveline may be e.g. depend on the prevailing driving conditions. In addition, the manner in which the torque transmitting means is engaged may have a significant impact on the load to which the powertrain is subjected. This is because the level of torque achieved by engagement is also highly dependent on dynamic torques that may occur in the acceleration of powertrain components by the torque transfer that has begun. When the driver operates the driver actuating means to control the torque transmitting means to sudden transmittable torque increases, a significant load of the driveline may be exerted, which is largely caused by dynamic torques. This load may reach a level that may result in damage to components of the vehicle and cause excessive wear. In addition, such Einkupplungen the torque transmitting means can be perceived as unpleasant for the driver.

In addition to the dynamic torques resulting from the engagement and disengagement of torque transmitting means, the actuation of the driver actuating means, e.g. an accelerator that allows the driver to control the load on the drive train. The driver may be a change of the driving force source, such. A request for a sudden increase or decrease in the torque to be supplied by the drive power source may result in a significant load imposed on the drive train, e.g. is caused by dynamic torques resulting from a sudden acceleration of the powertrain components. According to embodiments of the invention, the risk of undesirable torque levels arising in the driveline may be reduced.

According to the invention, this can be achieved by a method in which it is detected whether a change in the torque to be transmitted by the drive train is requested by the driver actuating means. For example, it may be recognized whether engagement of the torque transmitting means is requested by the driver actuating means. That is, it can be seen that the driver initiates engagement of the torque transmitting means, which detection may be accomplished, for example, by monitoring an electrical signal representing the position of the driver actuating means, wherein changes in the electrical signal into a corresponding movement, ie Position change, the driver actuating means can be implemented. The recognition may be carried out, for example, by the vehicle control or in another suitable manner. According to embodiments of the invention can be similarly recognized when the driver requests a change in the torque to be supplied by the driving force source by a monitoring the electrical signal that represents the position of the driver actuating means that controls the torque request, such as an accelerator pedal.

When a request for engagement of the torque transmitting means or a request to change the torque to be supplied by the driving power source is detected, a torque expected to occur in the driveline is predicted when the driver input requested change in the torque to be transmitted from the driveline is controlled , The change of torque transmission, such as the engagement of the torque transmitting means or the change in demand for torque from the driving force source may be influenced based on this prediction.

If it is predicted that the anticipated torque in the powertrain would possibly produce detrimental torque levels, if the change in torque transmission is controlled according to the driver's request, e.g. the engagement of the torque transmitting means are influenced in order to reduce the presumably occurring torques.

For example, if the transmission of the torque is interrupted, i. there is no ongoing torque transmission, the driving force source may rotate at a speed while the rotatable drive components connected downstream of the torque transmitting means are e.g. stand still or can turn at a different speed.

When the driver engages the torque transmission between the driving power source and the vehicle drive wheels so as to result in a sudden increase in the transmittable torque by the torque transmitting means, e.g. a depressed clutch pedal is released quickly, this can in particular lead to high dynamic torques, which can be harmful and can also lead to unpleasant jerking and / or vibrations in the drive train. The dynamic torque results from the acceleration of driveline components, which acceleration is caused by synchronizing rotating driveline components at different speeds by engaging the torque transmitting means.

The invention can be used to provide torque levels, such as e.g. to reduce dynamic torque levels and thereby reduce overstressing the driveline by affecting the engagement of the torque transmitting means. Torque levels arising in the powertrain as a result of engaging the torque transmitting means may be reduced to lower levels than those that would have prevailed if the engagement of the torque transmitting means had been completely controlled as requested by the driver actuating means.

Influencing the engagement of the torque transmitting means may include applying a limit on the rate of change of the transmittable torque of the torque transmitting means, wherein the limited rate of change may reduce dynamic torque levels. The bias may also include delaying and / or increasing an engagement time of the torque transmitting means relative to an engagement time when the engagement would be controlled according to the requirements of the driver actuating means. Likewise, a change in the demand for torque from the drive power source may be influenced to reduce the rate of change in reducing or increasing the torque to be provided by the drive power source as compared to a rate of change according to the driver's request. In this way, e.g. Acceleration of drivetrain components can be reduced, whereby the dynamic torque to which the drivetrain is exposed when engaging the torque transmitting means can be reduced.

As a result, adverse effects of undesirable driver behavior upon engagement of the torque transmitting means or upon changing a request for motive power from the motive power source can be reduced. With respect to demands for torque from the driving force source, the driver demand can also be influenced by controlling the clutch so that only a limited torque can be transmitted. The transmission of torque to the components of the drive train connected downstream of the clutch must not exceed the momentarily transmissible torque. Higher torques than the transmitted torque may still occur downstream of the clutch, but the transmittable torque limit may be used to reduce accelerations from the clutch downstream components and thus limit the generation of dynamic torques after clutch engagement.

If it is determined according to embodiments of the invention that the rate of change of the torque required by the driver in the Powertrain is below a threshold, no influence may be exercised.

According to embodiments of the invention, the rate of change of driver requested torque in the powertrain is determined based on the signal representing the position of the driver actuating means, for example, based on a change in the position of the driver actuating means. Additionally or alternatively, a rate of change of the position of the driver actuating means may be used in combination with an illustration of the effect on the torque transmission of the drive train caused by the actuation of the driver actuating means. By using e.g. a rate of change of the position of the driver actuating means, the change of the torque transmission through the drive train e.g. be predicted for an upcoming period of time, and if it is determined that the torque will exceed a certain limit / altitude in that time period, the change in torque transmission may be affected, e.g. to limit the dynamic torque that will occur.

When a driver's request for a change in torque to be transmitted by the driveline is detected, a delay may be imposed in the torque transfer control to allow the effect of controlling the torque transfer to be evaluated and optionally affected in accordance with the driver demand. Furthermore, various possible driver actions for different driving situations for a vehicle can be simulated, wherein the simulation can be carried out in the vehicle or in a system different from the vehicle. Potentially harmful driver requirements / behaviors may be identified and used as input when determining whether the driver's requested change in torque transmission should be affected. The simulation may e.g. for different vehicle speeds, different roadway inclinations and / or different vehicle loads are performed. The driver request may then be compared to such particular undesirable requests, and if undesirable driver actuation is detected, that actuation may be used as a prediction that the torque will reach undesirable levels. An explicit estimate of the expected torque is thus not required.

The demand for a change in the torque to be transmitted by the drive train may be e.g. be detected when a movement of the driver actuating means is detected. For example, a movement of the driver actuating means may be detected which controls the torque transmitting means from a position representing a complete interruption of the torque transmission toward a position representing a request for a complete transmission of the torque. For example, the driver actuating means may be actuated by the driver in a range of motion between a first end position representing a requirement for complete transmission of torque and a second end position representing a complete interruption of torque transmission. Therefore, the initiation of the engagement of the torque transmitting means can be recognized when a change in the position of the driver operating means from a position representing a complete interruption of the torque transmission of the torque transmitting device toward a position representing a higher transmittable torque is detected.

According to embodiments of the invention, the prediction of powertrain torque may include estimating whether the torque resulting in the powertrain will exceed a predetermined torque limit, wherein the change in powertrain torque transfer is affected only if the estimate indicates that the predetermined torque limit Torque limit will be exceeded. In this way, the required by the driver change in torque can only be influenced if harmful and / or unpleasant situations can occur.

The anticipated torque in the powertrain may be estimated as a torque that at least partially includes a dynamic torque that is likely to occur at a change in torque transmission required by the driver actuator. In general, a drive power source can exert a static torque on the drive train, which is determined, for example, by the amount of fuel injected. However, as mentioned above, in the acceleration of rotatable components, a dynamic torque that depends on the moment of inertia of the accelerated component (s) and the acceleration arises. If high accelerations of drivetrain components occur, this can cause high dynamic torques. By taking into account the dynamic torque, which will arise, for example, by the engagement of the torque transmitting means, a more accurate determination of the load to be applied to the drive train may be made Determining whether the change of torque transmission is to be influenced, be taken into account.

The expected dynamic torque may be estimated based on a simulation of the powertrain, e.g. using a mathematical representation of the powertrain, wherein resulting dynamic torques occurring in the driveline may be simulated / estimated taking into account given relevant input parameters, such as torque transmitted by the torque transmitting means and / or rotation of driveline components. The estimation of the torques in the drive train is a simple task for the expert, as well as the generation of drive train representations.

The prediction of torque may also be based on a request for motive power from the motive power source. The requirement of driving force affects the static torque exerted on the drive train and may further affect the dynamic torque that may occur upon engagement of the torque transmitting means, since the static torque generated by the driving force source may accelerate components.

In influencing the engagement of the torque transmitting means, the interference may be such that a maximum torque transmitted by the torque transmitting means is kept below a predetermined torque limit, e.g. rotating components are synchronized to such an extent that further engagement does not cause a maximum torque exceeds the predetermined torque limit.

Furthermore, the engagement of the torque transmitting means may e.g. be influenced by slower engagement of the torque transmitting means, so that an acceleration of a speed of at least one drive train component is kept below an acceleration limit, thereby ensuring that undesirable dynamic torques do not occur.

The engagement of the torque transmitting means may be affected as long as it is expected that a maximum torque in the drive train exceeds the predetermined torque limit.

According to embodiments of the invention, the driver actuating means comprises a pedal to be operated by a foot of the driver, for example a clutch pedal or accelerator pedal.

The torque transmitting means may include a clutch, such as a clutch. a friction clutch. The torque transmitting means for controlling the transmission of torque to / from a driving power source may also have other constructions. For example, a conventional clutch may be replaced by a torque transmitting means comprising one or more electric machines and a suitable gear transmission, this other type of torque transmitting means still being e.g. between a driving power source, such as an internal combustion engine, and a transmission, e.g. B. a transmission with different gears, can be arranged. With respect to such other torque transmitting means, the gear transmission may be e.g. comprise one or more planetary gear or other suitable gear transmission, wherein the electric machine (s) and the driving force source (s), such as an internal combustion engine, may be arranged in a torque balanced relationship such that when no torque from the electric machine is applied, this limits the torque, which can be transmitted from the drive power source to the transmission, to substantially zero, and wherein a higher torque exerted by the electric machine allows a higher transmission of torque from the driving power source, wherein the torque of the driving power source can be applied, which can be the torque exerted by the electric machine multiplied by a factor. In this embodiment, the vehicle may include a drive power source in the form of an internal combustion engine, while the functionality equivalent to a slip clutch may be achieved by controlling torque transmission through the electric machine.

Driver actuating means, such as a pedal, may then be used, with a first end position, such as a released pedal, a high, maximum transmittable torque request, similar to a closed clutch, and a second end position, such as a depressed pedal Transmission, such as a zero moment, by controlling the electric machine, for example, to provide a zero moment can represent. The electric machine may be controlled to provide a different transmittable torque to / from the motive power source depending on the position of the driver actuating means. The driver can additionally control the speed of the driving force source by the simultaneous operation of an accelerator pedal. Such solutions allow different speeds of the drive power source and the transmission input shaft, wherein the speeds are synchronized at higher torques. Such solutions can be used, for example, if Embodiments of the invention in hybrid vehicles, such as electric hybrid vehicles, realized.

Moreover, as will be understood by one skilled in the art, torque transmitting means, such as couplings and other means, may be of a different type, and the particular type, e.g. Whether or not the clutch is a friction clutch is not relevant to the present invention. The present invention can be used in any system with clutch-by-wire functionality, regardless of whether an actual clutch is present.

It should be understood that the embodiments described with respect to the method aspect of the present invention are also applicable to the system aspect of the present invention. That is, the system can be configured to perform the method as defined in any of the embodiments described above. Furthermore, the method may be a computer-implemented method.

Further features of the present invention and its advantages are given in the following detailed description of embodiments and the accompanying drawings.

list of figures

• 1A illustrates a powertrain of an exemplary vehicle;
• 1B illustrates an example of a control unit in a vehicle controller;
• 1C illustrates a clutch pedal of the exemplary vehicle of 1A represents.
• 2 FIG. 3 illustrates an exemplary method according to embodiments of the invention. FIG.
• 3 FIG. 10 illustrates an exemplary clutch pedal characteristic of a vehicle in which the present invention can be advantageously used.
• 4A-D represent the emergence and limitation of dynamic torque in a drive train.

Detailed description of exemplary embodiments

As discussed above, according to embodiments of the invention, it is recognized whether a change in torque to be transmitted from the powertrain is requested by a driver actuation means, the driver actuation means e.g. a means for controlling the transmission of torque or e.g. may be an accelerator pedal for requesting the torque from a driving power source. However, the embodiments of the invention will be explained below by way of example primarily with regard to a demand for a change in the torque to be transmitted by the drive train using torque transmission means. The examples can be applied analogously when a change in the torque to be supplied by a driving force source is required, e.g. when torque transmitting means, such as a clutch, if present, are closed.

Furthermore, as mentioned above, with respect to torque transmitting means, the embodiments of the invention are applicable not only to systems with a clutch but to all types of systems in which controllable torque transmitting means are used to control the transmission of torque to and / or from a drive power source using driver actuating means to control. As further mentioned above, such systems may e.g. Systems in which an electric machine and a gear transmission are used to provide the functionality of a conventional clutch, e.g. in hybrid electric vehicles.

However, in the following detailed description, for the sake of simplicity, the embodiments of the invention will be exemplified for a system in which a clutch is controlled with driver operating means. Further, the driver operating means for controlling a clutch will be exemplified by a clutch pedal in the following detailed description. However, the present invention is applicable to any type of driver operating means for controlling a clutch, wherein the driver operating means is movable in a range of movement.

1A schematically shows a powertrain of an exemplary vehicle 100 , The powertrain includes a drive power source, in the present example an internal combustion engine 101, conventionally via an output shaft of the internal combustion engine 101, normally via a flywheel 102 , with a gear 103 via a clutch 106 connected is. An output shaft 107 from the transmission 103 drives the drive wheels 113 . 114 via a final drive 108 like a common differential, and the drive axles 104 . 105 on, with the final drive 108 are connected.

The internal combustion engine 101 is controlled by a vehicle controller via a control unit 117. The coupling 106 and the gearbox 103 are also from the vehicle control via a control unit 116 controlled. According to the present example, the coupling comprises a Dry clutch in which a friction element (disc) 110 with a first transmission element, for example an input shaft 109 of the transmission 103 , is connected and rotated with this. The friction element 110 optionally engages the flywheel 102 or another suitable rotating part of the internal combustion engine 101 to the torque from / to the internal combustion engine 101, ie between the internal combustion engine 101 and that of the clutch 106 downstream powertrain components, such as to / from at least one of the drive wheels 113 . 114 , about the gearbox 103 transferred to.

The attack of the friction element 110 on the engine flywheel 102 is about a pressure plate 111 by means of a lever arm 112 controlled by a clutch actuator 115 is actuated.

In fully mechanical systems, where the clutch is controlled directly by a clutch pedal, the clutch pedal is mechanically connected to the clutch. For example, the clutch pedal may be mechanically connected to the lever arm to directly control the movement of the friction element. That is, a movement of the clutch pedal is mechanically connected to the clutch, and a movable clutch member such as a friction member moves synchronously with the clutch pedal. It should be understood that the example clutch is only an example, and that clutches may have various configurations regardless of whether the clutch is part of a clutch-by-wire system or is mechanically controlled by driver actuation means. For example, the clutch actuator can be arranged coaxially with the transmission input shaft.

In clutch-by-wire systems, such as the system exemplified herein, the opening and closing of the clutch 106 by the driver using driver actuating means, such as a clutch pedal 118 , to be controlled. In this case, however, the clutch pedal controls the influence of the clutch actuator 115 on the lever arm 112 not directly via a mechanical connection. Instead, the clutch is controlled by the vehicle controller in response to one or more signals representing the position of the clutch pedal 118.

Because the actual movement of the lever arm 112 is not mechanically connected to the clutch pedal 118, this in turn means that the position of the clutch pedal 118 is instead used as a request for a particular transmittable torque, eg represented by a position of the clutch friction element / actuator, which then by means of the vehicle control in an actual clutch movement the clutch actuator 115 is implemented. The actual actuation of the clutch, that is, in the present example, the positioning of the lever arm 112, thus takes place by the vehicle control, when the clutch is controlled by the driver, this being actuated by the position of the clutch pedal 118 is dependent.

However, since the actual actuation is controlled by the vehicle controller, this allows the clutch to be also controlled by the vehicle controller completely independently of the clutch pedal. The clutch can therefore be controlled according to various modes, wherein the actual clutch movement is always performed by the vehicle controller, but the movement is in a driver-controlled mode based on signals representing the position of the clutch pedal, and in an automatic mode the clutch movement is independent the current position of the clutch pedal is executed.

An exemplary clutch pedal 118 is schematic in 1C shown. The clutch pedal 118 is movable within a range of motion defined by two end positions A, B defining an angular range α. The position of the clutch pedal 118 in this range of motion, for example, by a suitable sensor, such as a potentiometer or an angle sensor 119 or any other suitable sensor that determines the current position of the clutch pedal 118 in the range of motion in which the clutch pedal is allowed to move. When the clutch pedal 118 is completely released, that is not actuated by the driver, it is in position A in a resting state, eg by a spring force, wherein position A represents a fully closed clutch. Position B represents a fully depressed clutch pedal and thus a fully opened clutch. 1A further discloses an accelerator pedal 130 with which the driver is driving power from the internal combustion engine 101 requests.

As mentioned above, the clutch can be controlled depending on the clutch pedal (driver operating means). An advantage of clutch-by-wire systems, however, is that the clutch can also be controlled independently of the clutch pedal by the vehicle control. This is also often used, for example, to allow the vehicle to be run on demand as a two-pedal vehicle (accelerator, brake pedal), the clutch pedal can be used for additional control, as described above. According to embodiments of the invention, a method and system is provided that provides additional security against noxious engagement of the torque transmitting means by occurrence and / or failure Increase driver comfort when engaging torque transmission means can offer. In 2 is an exemplary process 200 represented in the present invention, which at least partially, for example, in the control unit 116 for controlling the clutch 106 and the transmission 103 can be implemented. As noted above, the functions of a vehicle are generally controlled by multiple controllers, and control systems in vehicles of the type disclosed generally include a communications bus system that includes one or more communication buses for connecting multiple electronic control units (ECUs) or controls to various components on board of the vehicle. Such a control system may include a large number of control units, and the control of a particular function may be divided into two or more of them.

For the sake of simplicity, in 1A only the control units 116 - 117 shown, where vehicles 100 The type shown are often equipped with significantly more control units, as one skilled in the art will understand. The control units 116 - 117 are arranged to communicate with each other and with various components via the communication bus system and other lines, which are partially connected by connecting lines 1A are displayed.

Embodiments of the invention may be used in any suitable control unit in the vehicle 100, and thus not necessarily only in the control unit 116 will be realized. The control of the clutch 106 According to embodiments of the invention, it will normally depend on signals received from other controllers and / or vehicle components, and it is generally the case that controllers of the type disclosed for receiving sensor signals from various parts of the vehicle 100 are suitable. The control unit 116 For example, signals from the clutch pedal position sensor 119 and the clutch actuator 115 receive. Further, the control unit may receive signals representative of a driver's request for motive power from the internal combustion engine, such as by the accelerator pedal 130 , The controller may further signals eg with respect to a speed of the transmission input shaft 109 and / or receive other signals from which rotational speeds of powertrain components may be determined. Control units of the type shown are normally adapted to provide control signals to various parts and components of the vehicle, for example to control the clutch actuator 115.

Control of this kind is often done by programmed instructions. The programmed instructions typically include a computer program that, when executed in a computer or control unit, causes the computer / controller to perform the desired control, such as method steps, in accordance with the present invention. The computer program usually forms part of a computer-readable medium, the computer-readable medium being a suitable storage medium 121 includes (see 1B ) and the computer program 126 on the storage medium 121 is stored. The computer program can be stored in non-volatile memory on this storage medium. The digital storage medium 121 may include, for example, one of the following groups, including ROM (read-only memory), PROM (Programmable Read-Only Memory), EPROM (erasable PROM), flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc. , and may be located in or in connection with the control unit, whereupon the computer program is executed by the control unit. The behavior of the vehicle in a particular situation can thus be adjusted by changing the instructions of the computer program.

An exemplary control unit (the control unit 116 ) is in 1B schematically illustrated, wherein the control unit is a processing unit 120 For example, it may include any suitable type of processor or microcomputer, such as a Digital Signal Processor (DSP) or an Application Specific Integrated Circuit (ASIC). The processing unit 120 is connected to a memory unit 121, which is the processing unit 120 For example, the stored program code 126 and / or the stored data that the processing unit 120 needs to perform calculations may be provided. The processing unit 120 is further arranged to provide partial or final results of calculations in the memory unit 121 save.

In addition, the control unit 116 with the devices 122 . 123 . 124 . 125 equipped to receive and send input or output signals. These input and output signals may include waveforms, pulses or other attributes that the devices 122 . 125 for receiving input signals as information for processing by the processing unit 120 can recognize. The devices 123 . 124 for sending output signals are set up, calculation results from the evaluation unit 120 in output signals for transmission to other parts of the vehicle control and / or to the component (s) for which the signals are intended to convert. Every single one of them Connections to the devices for receiving and transmitting the respective input and output signals may include one or more of a cable, a data bus such as a Controller Area Network Bus (CAN), a Media Oriented Systems Transport (MOST) bus, or any of the other other bus configuration or a wireless connection.

With reference again to the in 2 illustrated exemplary method 200 , the procedure begins in step 201 , As mentioned above, the embodiments of the invention relate to a method and system for reducing the risk of damaging torques occurring in the drivetrain when engaging torque-transmitting means, such as a clutch. In addition, the comfort for the driver can be increased. The method according to embodiments of the invention may be arranged to be performed only when the speed of the vehicle is below a predetermined speed or when the vehicle is stationary. In such situations, the engagement of the torque transmitting device may often result in excessive torque. This is because at low vehicle speeds and / or when the vehicle is at a standstill, large speed differences of the powertrain components may predominate. However, high dynamic torques can also occur independently of the vehicle speed, if, for example, a step change occurs in the transmittable torque of the torque transmission device. According to embodiments of the invention, the method is performed whenever a request to engage the clutch 106 is recognized.

In step 201 it is determined whether the torque transmitting means, in this case the clutch 106 , is disengaged. According to embodiments of the invention, it is necessary that the clutch 106 is completely open, that is, the torque transmission is completely interrupted, such as when the friction disc 110 the flywheel 102 not contacted. According to embodiments of the invention, the method is performed when there is a speed difference across the clutch 106. The procedure remains in step 201 as this is not the case while the procedure is in step 202 continues to run when the clutch 106 is disengaged.

In step 202 determines whether a clutch engagement 106 is requested. If this is not the case, the method returns to step 201 back while the procedure is in step 203 continues to run when a coupling is requested. Whether engagement of the clutch is requested or not can be achieved, for example, by detecting movement of the clutch pedal 118 from position B ( 1C ), which is a complete interruption of torque transmission, toward position A, which is a request for complete transmission of torque, ie, a closed driveline. The movement may also be detected by the vehicle controller monitoring an electrical signal indicative of the position of the clutch pedal 118 represents. As mentioned, clutch movement may be required to be detected from a fully open position, but it may be sufficient to detect movement from any position toward position A as long as there is a difference in rotational speed across the clutch is present, ie no or a limited torque can be transmitted from the clutch, since if the clutch is able to transmit higher torques than those currently being transmitted from the drive train, no difference in the speed between the engine and transmission input shaft present will be.

In step 203 is determined whether the engagement of the torque transmitting means to be influenced. As already mentioned, the engagement of the clutch can be arranged to always be affected while engaging the clutch 106 According to the embodiments of the invention can be arranged so that it is only affected if some criteria are met.

For example, the engagement of the clutch 106 be set so that it is only affected if it is determined that the coupling of the clutch causes a potentially harmful torque in the drive train. In step 203 Therefore, a representation of the torque that is likely to occur in the powertrain upon engagement in accordance with the driver's request may be predicted to determine if the torque is likely to exceed a threshold that is considered potentially harmful.

With the clutch open 106 There is no ongoing torque transmission because the torque transmission is interrupted. Stands the vehicle 100 Silently, the output shaft of the internal combustion engine and thus the flywheel rotates 102 with the current speed of the internal combustion engine 101 , The transmission input shaft 109 on the other hand, it is at least quiet when gears are engaged. This also applies to the PTO shaft 107 and the drive shafts 104 . 105 , When the driver suddenly gets his foot off the clutch pedal 118 takes or otherwise tries to close the clutch so that the transmissible torque of the clutch 106 rises quickly, eg by quickly releasing the clutch pedal 118 For example, this will produce a torque load that not only includes static torque generated by the engine, ie work produced by injecting fuel, but that will consist to a large extent, or even primarily, of dynamic torque.

The dynamic torque is generated by the acceleration of the powertrain / engine components. The acceleration may occur when different speeds of the flywheel and the transmission input shaft are synchronized when the clutch engages and the transmittable torque of the clutch increases. If, for example, the internal combustion engine rotates at one speed and the transmission input shaft rotates with another, these speeds are inevitably synchronized when the clutch is engaged. When the clutch closes quickly, the acceleration becomes high, causing high torque. In the present example, with the clutch suddenly closed, the internal combustion engine is braked by the still standing drive train and thereby exposed to a high negative acceleration when the internal combustion engine tries to set the vehicle in motion by rotating and accelerating the transmission input shaft. Likewise, powertrain components may be accelerated when the demand for torque from the driving force source changes rapidly, e.g. when the driver suddenly depresses or releases an accelerator pedal. Acceleration of powertrain components can result in high dynamic torque being applied to the powertrain. The magnitude of the dynamic torque depends on the moment of inertia of the rotating / moving parts of the internal combustion engine, which can be significant.

wobei ṅ die Beschleunigung des Antriebsstrangs und J das Trägheitsmoment, z.B. des zu beschleunigenden Bauteils ist. Das dynamische Drehmoment kann für die der Kupplung nachgeschalteten Antriebsstrangkomponenten ermittelt werden, wenn diese beschleunigt werden. Wenn die Beschleunigung hoch ist, kann das resultierende dynamische Drehmoment hoch sein und kann das maximale Drehmoment, für das der Antriebsstrang ausgelegt ist, übersteigen und dadurch möglicherweise Antriebsstrangkomponenten beschädigen.The dynamic torque caused by the moment of inertia and the acceleration of a powertrain component can be determined as follows: $$T=\dot{n}J$$

where ṅ is the acceleration of the drive train and J is the moment of inertia, eg the component to be accelerated. The dynamic torque can be determined for the clutch downstream powertrain components as they are accelerated. If the acceleration is high, the resulting dynamic torque may be high and may exceed the maximum torque that the powertrain is designed to, thereby potentially damaging powertrain components.

In step 203 Therefore, at least the occurring dynamic torque can be estimated. This can be done in any suitable way. Factors such as the moment of inertia are well known for the powertrain and internal combustion engine components, and as noted above, the dynamic torque caused by the moment of inertia and acceleration of one or more powertrain components may be estimated based on a mathematical representation of the powertrain The resulting dynamic torques may be estimated based on relevant input parameters, which may also take into account the rotation and torque applied by the driving wheels of the vehicle, which may counteract the rotation and cause vibrations, as shown below. For example, if there is an indication of a sudden increase in the transmittable torque of the clutch, determined, for example, by monitoring the movement of the clutch pedal, the predicted increase in transmittable torque can be used to estimate the resulting resulting dynamic torques.

As long as the transmittable torque is kept low, a high speed differential across the clutch can be maintained, thereby limiting the acceleration of the powertrain components as well. However, if the transmittable torque is increased rapidly, such as by suddenly releasing the clutch pedal, high acceleration may be unavoidable, thereby causing high dynamic torques.

This is in the 4A-D shown. In 4A represents the dashed line 401 According to the illustrated situation, the vehicle is stationary and the torque increase is not sufficient to overcome the driving resistance, ie the torque exerted by the driving wheels and to set the vehicle in motion. Thus, the vehicle remains despite an applied torque. The line 402 represents the resulting dynamic torque created by the sudden increase in torque on the transmission input shaft. How out 4A As can be seen, the dynamics are significantly higher than the torque actually applied to the transmission input shaft by the engine and limited by the currently transmissible torque of the clutch. 4B shows the acceleration of the transmission input shaft, which causes the dynamic torque, starting from zero, since the vehicle is stationary. Since the applied torque is not sufficient to overcome the driving resistance, the twisted by the Acceleration of the transmittable torque caused acceleration of the transmission input shaft, whereby an oscillating acceleration and thus an oscillating dynamic torque is caused. In this way, the sudden increase in torque can cause harmful torques. As already mentioned, the occurring dynamic torques can be estimated from a mathematical representation of the drive train in combination with relevant input parameters. This can be done, for example, when detecting clutch operations, but according to the embodiments of the invention harmful situations can be detected in advance, eg in the vehicle development phase, in which case the vehicle control does not have to make any current estimates of the torque occurring, but the vehicle control instead situations which can lead to harmful torques. For example, simulations in advance may already have identified situations that may lead to detrimental dynamic torques, and when such situations are identified, measures according to the invention may be taken. These measures may include limiting the speed at which the transmittable torque of the clutch is increased.

4C represents the situation of 4A but with the increase instead 404 the transmittable torque according to embodiments of the invention is controlled so that it is slower, that is, the rate of change is reduced. That is, the clutch is closed at a speed slower than requested by the driver. How out 4D is apparent, there is essentially no acceleration 406 the transmission input shaft, and the resulting drive torque 405 is essentially equal to the torque increase and thus the load on the drive train is reduced. Thus, according to embodiments of the invention, sudden / rapid closing operations of the clutch may be prohibited and the transmittable torque may be adjusted to increase more slowly. For example, various potentially harmful behaviors of the driver may be detected in advance by simulations, and if the control system determines the likely occurrence of such a situation, the clutch closure may be affected.

When and to what extent the clutch will engage can be determined, for example, by the use of a clutch characteristic. 3 _{FIG. 12} shows an example of a characteristic P _char1 for an exemplary clutch of a type as used in a vehicle of _FIG 1A can be used. The y-axis denotes the transmittable torque T, ie the torque that drives the clutch 106 between internal combustion engine 101 and input shaft of the transmission 103 can transfer. In general, the x-axis designates the clutch position, such as the clutch actuator position and / or the lever arm position. The x-axis may also be the position of the clutch pedal 118 represent.

The origin, "0", represents the open position of the clutch, ie a position in which the clutch pedal 118 and usually the friction element (the lever arm / the clutch actuator) in its one end position, position B in Fig. 1C, are located. This corresponds to a fully depressed clutch pedal 118 and the friction element 110 is completely from the combustion engine 101 separated, ie, as shown in Fig. 1A, positioned on the right side. Conversely, the position "closed clutch" represents a fully released clutch pedal. This means the position A in Fig. 1C, wherein the friction element 110 as close as possible to the flywheel and thereby pressed example by means of a spring action against the flywheel. T _max represents the maximum transmissible torque. When the clutch is fully open, the friction element is located 110 normally at a distance from the flywheel of the engine such that closing the clutch involves the friction element and thus the clutch pedal, which initially travels a distance x1 before contacting the flywheel. As soon as the friction element precisely contacts the flywheel, the torque transfer between the engine and the remaining drive train can begin at the contact point CP. The further the clutch closes from this point (ie, the stronger the friction element 110 on the flywheel 102 engages), the more torque can be transmitted via the clutch 106.

Therefore, a characteristic of in 3 used to determine when the clutch will engage and further, how the transmittable torque will change when closing the clutch. The speed at which the clutch pedal closes can be monitored, for example, from the signals representing the position of the clutch pedal, and thereby further, for example, by the use of a characteristic according to FIG 3 , or simply by operating the driver actuator, potentially harmful situations are detected. For example, if a closing speed of the clutch can be estimated based on the current clutch movement and it can be assumed that the closing will continue at the same speed and the resulting drive torque can be predicted for a time t, and if the torque at any time during this Time t exceeds a torque limit, then it can be determined that the closing of the clutch should be affected. A delay in the current control of the clutch may be imposed in accordance with the driver's requirements for the determination to be made.

So if in step 203 is determined that the engagement of the torque transmitting means is to be influenced, the method continues to step 204 , Otherwise, the procedure may go to step 207 go where it is determined whether the clutch is closed. The method can then be set to step 203 returns, as long as this is not the case. In this way it can be ensured that the closing of the clutch can be influenced in situations in which initially no influence is required, but in which it can be determined later when closing the clutch that an influencing is actually required, for example because the driver suddenly increases the closing speed of the clutch. After closing the clutch, the process may be terminated in step 206.

In step 204 a suitable control of the clutch engagement is determined, wherein the clutch is preferably controlled so that the clutch closes at a slower speed than required by the driver actuating means, such as in the 4A-D shown. The control of the clutch 106 is further in step 204 started if it is influenced according to the method. This interference can be achieved by controlling the clutch actuator / friction disc differently than the control required by the clutch pedal so that the clutch closes as if the clutch pedal has been released more slowly.

As explained above, slower clutch closing will result in a slower increase in transmittable torque and the transmission input shaft will accelerate more slowly. Thus, the speed of the transmission input shaft can be synchronized better controllable, whereby a lower acceleration of the components and thus a lower dynamic torque is caused.

In addition, a potentially harmful driver behavior using the accelerator pedal, for example, be recognized in advance, in which case similar measures can be taken. Regarding dynamic torques caused by sudden changes in the demand for torque from the vehicle drive power source, e.g. As an internal combustion engine, the drive train can be protected by the speed of change is reduced compared to the request of the driver, but also by the clutch is controlled so that at most a predetermined torque can be transmitted, since the internal combustion engine on the the clutch downstream powertrain can not exert a higher torque than the clutch can currently transmit. Furthermore, the clutch can be kept at least partially open, ie with a reduced transmittable torque, until the vehicle 100 is set in motion so that a rotational speed of the transmission input shaft substantially equal to the rotational speed of the internal combustion engine 101, so that the clutch 106 can be closed without undesirable changes in the torque transmission, such. As an increase to an undesirable torque level caused.

In step 205 it is determined, whether influencing of coupling of coupling 106 should be continued, for example, when the clutch 106 not yet engaged and / or because the speed difference across the clutch 106 is still above a predetermined limit, the case of abrupt closing of the clutch 106 can lead to unwanted acceleration. If the influence of the engagement of the clutch to be continued, the method may, for example, to step 204 return, where the control can be adjusted if necessary, for example by increasing the transmittable torque. If it is determined that the speed of the internal combustion engine should no longer be affected, for example because the clutch has engaged, the method in step 206 completed. According to embodiments of the invention, the coupling 106 accordingly, be set to be closed more slowly than required by the driver, thereby reducing the risk of occurrence of undesired situations.

Moreover, as stated above, embodiments of the invention are applicable even when the torque transmitting means has a construction other than a coupling, such as a torque transmitting means comprising one or more electric machines and a suitable gear transmission. Such constructions may provide the functionality of a coupling, which functionality may be controlled by a driver actuating means, eg in the form of a pedal. An example of such a system can be found in the international application PCT / SE16 / 050538 entitled "A drive system for a vehicle" and the same assignee as the present application. This referenced application is incorporated herein by reference.

In this type of systems, an internal combustion engine can be connected to a transmission input shaft via a planetary gear, for example, and furthermore an electric machine is connected to the planetary gear. For example, the internal combustion engine may be connected to a sun gear of the planetary gear, while the transmission may be connected to a carrier and the electric machine is connected to a ring gear. According to the solutions of the referenced application, the engine may rotate independently of the speed of the transmission input gear. Further, the electric machine and the internal combustion engine may be arranged in a torque balanced relationship such that when torque is not applied by the electric machine, this limits the torque that can be transmitted from the internal combustion engine to zero.

When the applied torque is increased by the electric machine, a higher torque can be transmitted to the transmission input shaft by the internal combustion engine, and the higher the torque transmission, the closer the rotational speeds will be to each other. When the electric machine applies torque equal to or greater than the torque that will be transmitted from the powertrain, the engine and transmission speeds are synchronized.

Consequently, the increase in transmittable torque according to embodiments of the invention may also be affected in systems of this type upon engagement of the torque transmitting means, such as by controlling an increase in the torque applied by the electric machine in response to e.g. a driver-actuated pedal that provides similar functions as a clutch pedal in a manner that increases the torque applied by the electric machine more slowly. The vehicle may be a hybrid vehicle, such as a hybrid vehicle. an electric hybrid vehicle, or any other type of vehicle with torque transmitting means of this type.

Embodiments of the invention may also be used in systems where an electric machine is connected to e.g. a transmission input shaft is connected and in which an accelerator pedal controls a request for torque from the electric machine. A change in the demand for torque from the electric machine using the accelerator pedal may be influenced according to the above embodiment.

Finally, the embodiments of the invention have been described above particularly for a particular example of a vehicle, but are applicable to any vehicle in which actuating means are used to control torque transmitting means. The torque transmitting means may be of any suitable type including any elements, e.g. a clutch or other type of solution as long as the operation of the torque transmitting means can be performed independently of the operation of the driver actuating means.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• SE 16/050538 [0074]

Claims (15)

Method for controlling the transmission of torque in a vehicle (100), wherein the vehicle (100) comprises: a drive train for transmitting torque between a drive power source (101) and at least one drive wheel of the vehicle (101), and a driver actuating means (118), wherein a torque to be transmitted by the drive train is controllable in response to an electrical signal representing a position of the driver actuating means (118), the method comprising: Detecting whether a change in the torque to be transmitted by the drive train is requested by the driver actuating means (118), - predicting a torque which is expected to occur in the drive train when the change in torque transmission required by the driver actuating means (118) is controlled, and - Affecting the change of the powertrain torque transmission based on this prediction. Method according to Claim 1 - wherein influencing comprises limiting a rate of change to increase or decrease the torque transmission of the powertrain. Method according to Claim 1 or 2 , wherein the prediction is based on the signal representing the position of the driver actuating means. Method according to one of the preceding claims, wherein the prediction based on a simulation and / or mathematical representation of the drive train. Method according to one of the preceding claims, wherein the prediction comprises comparing the requested change in torque to be transmitted by the powertrain with at least one predetermined request, and - Influencing the change in the torque transmission of the powertrain based on the comparison. Method according to one of the preceding claims, wherein the prediction is estimating whether the torque likely to occur in the powertrain will exceed a predetermined torque limit, and wherein the change in torque transfer is affected when the estimate indicates that the predetermined torque limit will be exceeded. Method according to one of the preceding claims, wherein: Estimating the torque likely to occur in the driveline as a torque that at least partially includes a dynamic torque that is likely to occur when the torque to be transferred is changed as requested by the driver actuator (118). The method of any one of the preceding claims, further comprising: Estimating a maximum torque expected to occur in the driveline when the torque transmission requested by the driver actuating means is changed during a time period T after the detection, and - Affecting the change of torque transmission based on the estimated maximum torque. Method according to one of the preceding claims, wherein the vehicle comprises a torque transmission means (106) for selectively transmitting torque between the drive power source (101) and the at least one drive wheel of the vehicle (100), wherein the transmittable torque of the torque transmitting means (106) is controllable in response to the electrical signal representative of a position of the driver actuating means (118), wherein the detection comprises detecting whether a change in torque to be transmitted from the driveline is requested by the driver actuating means (118), and influencing comprises influencing the engagement of the torque transmitting means (106) based on the prediction. Method according to Claim 9 wherein influencing the engagement of the torque transmitting means (106) includes delaying and / or reducing the rate of increase of the transmittable torque of the torque transmitting means (106) if the engagement were controlled as requested by the driver actuating means (118). Method according to Claim 9 or 10 wherein the engagement of the torque transmitting means is influenced such that an acceleration of a rotational speed of at least one drivetrain component is kept below an acceleration limit. A computer program that includes instructions that cause the computer to run if the program is run by a computer Method according to one of the preceding claims performs. A computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method of one of Claims 1 - 11 performs. System for controlling the transmission of torque in a vehicle (100), wherein the vehicle (100) comprises: a drive train for transmitting torque between a drive power source (101) and at least one drive wheel of the vehicle (101), and a driver actuating means (118), wherein a torque to be transmitted by the drive train is controllable in response to an electrical signal representing a position of the driver actuating means (118), the system comprising: means adapted to detect whether a change of the driveline torque to be transmitted is requested by the driver actuating means (118), a means arranged to predict a torque which is expected to occur in the drive train when the change in torque transmission required by the driver actuating means (118) is controlled, and a means configured to influence the change in powertrain torque transmission based on that prediction. Vehicle following a system Claim 14 includes.

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