WO2004028845A1

WO2004028845A1 - Method, device and the utilization thereof for operating a motor vehicle

Info

Publication number: WO2004028845A1
Application number: PCT/DE2003/003082
Authority: WO
Inventors: Mario Jung; Wolfgang Niessen; Markus Kneissler; Christoph Lindenschmidt; Reinhard Berger; Bard Vestgard; Havard Saksvikronning
Original assignee: Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority date: 2002-09-19
Filing date: 2003-09-17
Publication date: 2004-04-08
Also published as: AU2003275920A1; DE10392676D2

Abstract

The invention relates to a method, a device and the utilization thereof for controlling the drive train of a motor vehicle having an internal combustion engine, a manual transmission and an electric machine arranged in such a way that it interacts with the manual transmission, wherein a protective measure is executed depending on a given operating state of the motor vehicle in order to maintain safe and comfortable operation of the motor vehicle.

Description

Method, device and its use for operating a

motor vehicle

The invention relates to a method, a device and its use for operating a motor vehicle with a drive motor and a transmission in the drive train.

According to FIG. 1, a vehicle 1 has a drive unit 2, such as an engine or an internal combustion engine. Furthermore, a torque transmission system 3 and a transmission 4 are arranged in the drive train of the vehicle 1. In this exemplary embodiment, the torque transmission system 3 is arranged in the power flow between the engine and the transmission, a drive torque of the engine being transmitted via the torque transmission system 3 to the transmission 4 and from the transmission 4 on the output side to an output shaft 5 and to a downstream axis 6 and to the wheels 6a becomes.

The torque transmission system 3 is a clutch, such as. B. designed as a friction clutch, multi-plate clutch, magnetic powder clutch or torque converter clutch, the clutch can be a self-adjusting or a wear-compensating clutch. The transmission 4 is an uninterruptible manual transmission (USG). According to the idea of the invention, the transmission can also be an automated manual transmission (ASG), which can be shifted automatically by means of at least one actuator. An automated manual transmission is furthermore to be understood as an automated transmission which is shifted with an interruption in tractive force and in which the shifting operation of the transmission ratio is carried out in a controlled manner by means of at least one actuator.

Furthermore, an automatic transmission can also be used as the USG, an automatic transmission being a transmission essentially without interruption of tractive power during the switching operations and which is generally constructed by means of planetary gear stages. Furthermore, a continuously variable transmission, such as a conical pulley belt transmission, can be used. The automatic transmission can also be designed with a torque transmission system 3 arranged on the output side, such as a clutch or a friction clutch. The torque transmission system 3 can furthermore be designed as a starting clutch and / or a reversing set clutch for reversing the direction of rotation and / or a safety clutch with a selectively controllable, transferable torque. The torque transmission system 3 can be a dry friction clutch or a wet friction clutch that runs, for example, in a fluid. It can also be a torque converter.

The torque transmission system 3 has a drive side 7 and an output side 8, wherein a torque is transmitted from the drive side 7 to the output side 8 by z. B. the clutch disc 3a by means of the pressure plate 3b, the plate spring 3c and the release bearing 3e as well as the flywheel 3d. For this purpose, the release lever 20 is actuated by means of an actuating device, e.g. an actuator.

The torque transmission system 3 is controlled by means of a control unit 13, such as, for. B. a control unit, which may include the control electronics 13a and the actuator 13b. In another advantageous embodiment, the actuator 13b and the control electronics 13a can also be in two different structural units, such as Housing, be arranged.

The control unit 13 can contain the control and power electronics for controlling the drive motor 12 of the actuator 13b. In this way it can advantageously be achieved, for example, that the system, as the only installation space, requires the installation space for the actuator 13b with electronics. The actuator 13b consists of the drive motor 12, such as an electric motor, the electric motor 12 via a gear, such as a worm gear, a spur gear, a crank gear or a Threaded spindle gear, acts on a master cylinder 11. This effect on the master cylinder 11 can take place directly or via a linkage.

The movement of the output part of the actuator 13b, such as. B. the master cylinder piston 11a is detected with a clutch travel sensor 14 which detects the position or position or the speed or the acceleration of a variable which is proportional to the position or engagement position or the speed or acceleration of the clutch. The master cylinder 11 is connected via a pressure medium line 9, e.g. a hydraulic line, connected to the slave cylinder 10. The output element 10a of the slave cylinder is connected to the disengaging means 20, e.g. a release lever, operatively connected, so that a movement of the output part 10a of the slave cylinder 10 has the effect that the release means 20 is also moved or tilted in order to control the torque that can be transmitted by the clutch 3.

The actuator 13b for controlling the transferable torque of the torque transmission system 3 can be actuatable by pressure medium, i.e. it can have a pressure medium transmitter and slave cylinder. The pressure medium can be, for example, a hydraulic fluid or a pneumatic medium. The actuation of the pressure transmitter cylinder can be done by an electric motor, the as

Drive element 12 provided electric motor can be controlled electronically. The drive element 12 of the actuator 13b can in addition to an electromotive

Another drive element, for example pressure-operated

Be drive element. Magnetic actuators can also be used to adjust a position of an element.

In the case of a friction clutch, the transferable torque is controlled in that the friction linings of the clutch disc are pressed in a targeted manner between the flywheel 3d and the pressure plate 3b. The application of force to the pressure plate 3b or the friction linings can be controlled in a targeted manner via the position of the disengagement means 20, such as a release fork or a central release device, the pressure plate 3b being between two End positions can be moved and set and fixed as desired. The one

End position corresponds to a fully engaged clutch position and the other

End position of a fully disengaged clutch position. To control a transmissible torque, which is, for example, less than the engine torque currently present, a position of the pressure plate 3b can be controlled, for example, that in an intermediate area between the two

End positions. The clutch can by means of the targeted control of the

Disengaging means 20 are fixed in this position. But it can also be transferable

Coupling torques are controlled that are defined above the current engine torque. In such a case, the currently occurring engine torques can be transmitted, the torque

Non-uniformities in the drive train in the form of, for example

Torque peaks are damped and / or isolated.

To control the torque transmission system 3, sensors are also used which at least temporarily monitor the relevant variables of the entire system and deliver the state variables, signals and measured values necessary for control, which are processed by the control unit, with a signal connection to other electronic units, such as, for example Engine electronics or an electronics of an anti-lock braking system (ABS) or an anti-slip control (ASR) can be provided and can exist. For example, the sensors detect speeds such as wheel speeds, engine speeds, the position of the load lever, the throttle valve position, the gear position of the transmission, an intention to shift and other vehicle-specific parameters.

1 shows that a throttle valve sensor 15, an engine speed sensor 16 and a speedometer sensor 17 can be used and transmit measured values or information to the control unit 13. The electronic unit, such as a computer unit, of the control electronics 13a processes the system input variables and forwards control signals to the actuator 13b. The transmission is designed as a step change transmission, for example, the gear ratios being changed by means of a shift lever 18 or the transmission being actuated or operated by means of this shift lever 18. Furthermore, at least one sensor 19b is arranged on the shift lever 18 of the manual transmission, which detects the intention to shift and / or the gear position and forwards it to the control unit 13. The sensor 19a is articulated on the transmission and detects the current gear position and / or an intention to shift. The intention to shift is detected using at least one of the two sensors 19a, 19b in that the sensor is a force sensor which detects the force acting on the shift lever 18. Furthermore, the sensor can also be designed as a displacement or position sensor, the control unit recognizing an intention to switch from the change in the position signal over time.

The control unit 13 is at least temporarily in signal connection with all sensors and evaluates the sensor signals and system input variables in such a way that the control unit issues control or regulation commands to the at least one actuator 13b as a function of the current operating point. The drive motor 12 of the actuator 13b, e.g. an electric motor receives from the control unit, which controls the clutch actuation, a manipulated variable as a function of measured values and / or system input variables and / or signals from the connected sensors. For this purpose, a control program is implemented in the control unit 13 as hardware and / or as software, which evaluates the incoming signals and calculates or determines the output variables on the basis of comparisons and / or functions and / or characteristic maps.

The control unit 13 has advantageously implemented a torque determination unit, a gear position determination unit, a slip determination unit and / or an operating state determination unit or is in signal connection with at least one of these units. These units can be implemented by control programs as hardware and / or as software, so that by means of the incoming sensor signals, the torque of the drive unit 2 of the vehicle 1, the gear position of the transmission 4 and the slip that prevails in the area of the torque transmission system 3 and the current one Operating state of the vehicle 1 can be determined. The gear position determination unit determines the currently engaged gear on the basis of the signals from the sensors 19a and 19b. The sensors 19a, 19b are articulated on the shift lever and / or on gearbox-internal adjusting means, such as a central shift shaft or shift rod, and detect them, for example the position and / or the speed of these components. Furthermore, a load lever sensor 31 can be arranged on the load lever 30, such as on an accelerator pedal, which detects the load lever position. Another sensor 32 can act as an idle switch, ie when the load lever 30 or accelerator pedal is actuated, this idle switch 32 is switched on and when the load lever 30 is not actuated, it is switched off, so that digital information can be used to identify whether the load lever 30 is actuated. The load lever sensor 31 detects the degree of actuation of the load lever 30.

1 shows, in addition to the load lever 30 and the sensors associated therewith, a brake actuating element 40 for actuating the service brake or the parking brake, such as e.g. a brake pedal, a hand brake lever or a hand or foot operated actuator of the parking brake. At least one sensor 41 is arranged on the actuating element 40 and monitors its actuation. The sensor 41 is, for example, a digital sensor, such as. B. designed as a switch, which detects that the brake actuator 40 is operated or not. With the sensor 41, a signaling device, e.g. a brake light, in signal connection, which signals that the brake is applied. This can be done for both the service brake and the parking brake. However, the sensor 41 can also be designed as an analog sensor, such a sensor, such as a potentiometer, determining the degree of actuation of the brake actuating element 41. This sensor can also be in signal connection with a signal device.

A possible embodiment of the present invention is described below, in which active braking, in particular in shifting operations in overrun mode, is proposed for a vehicle. It is an object of the present invention to improve comfort, particularly in downshifts when driving downhill.

Accordingly, e.g. B. by using an active braking system, such as. B. an ESP system, an electro-hydraulic brake, a brake-by-wire system or the like, the engine braking effect can be replaced for a short time.

During e.g. B. an ASG circuit in overrun mode, the missing engine braking effect can be applied by the active brake to the level that is to be expected after re-engagement on the wheel. It is conceivable that this procedure is also modified appropriately in order to obtain further improvements in comfort. It is possible that this procedure is also implemented for other switching operations.

The present invention can preferably be used in all vehicles with automatic or automated transmissions.

A further embodiment is described below in which an automatically operated parking lock without a holding magnet is proposed.

It is known that in the case of an automatically operated parking lock, which is actuated by the active interlock, an electromagnet is provided in order to block the parking lock in the open state.

To avoid the additional effort for this electromagnet, purely mechanical solutions can also be provided for a parking lock. For this purpose, the parking lock should be able to be both engaged and disengaged through the gear actuator.

In this case, it is advantageous to use the movement of the shift finger to actuate the parking lock only in one direction, so that the other alley in the H shift pattern can be used for another gear or stop. FIG. 2 shows an exploded view of a possible automatically operated parking lock without the use of a holding magnet. The functioning of this parking lock is similar to the functioning of a ballpoint pen.

FIGS. 3 to 5 show further views of the proposed solution according to the invention. The parking lock according to the invention essentially consists of an actuating sleeve 51, preferably with a pointed, wedge-shaped or similar toothing. An actuating bolt 52 is also provided, a bearing cap 53 also being provided with a wedge-shaped toothing between the actuating bolt and the actuating sleeve.

In Figure 3, the parking lock is installed in a gearbox .54. In this illustration, the pawl 55 is outside the ratchet wheel. For resetting, a return spring 56 or the like is preferably provided on the actuating bolt 52.

The parking lock according to the invention is shown in FIG. 4 in a state in which it is actuated by a switching element. In contrast to FIG. 3, the state of the parking lock in FIG. 4 is changed. It is an intermediate stage.

5 shows the parking lock in an inserted state. In this state, the locking wheel 57 of the parking lock is blocked by the pawl 55. In this way, the ratchet wheel 57 is firmly connected to the transmission countershaft.

The force FA indicated by an arrow in FIG. 4 represents the force of the shift finger which acts on the actuating sleeve 51 when the state of the parking lock is to be changed. Due to the pointed toothing on the end of the actuating sleeve 51 facing the bearing cap 53, the bearing cap 53 and thus also the actuating bolt 52 of the parking lock can be displaced in the direction of the force FA. The parking lock in FIG. 4 or FIG. 5 is thus shifted to the right. The actuating sleeve 51 and the bearing cap 53 or bearing cap can be guided, for example, by suitable grooves in the gear housing bore. A pointed or similar toothing is also provided on the bearing cap 53. If the bearing cap 53 with the actuating sleeve 51 and the switching element of the gear actuator is moved such that the teeth of the bearing cap are outside the grooves of the gear housing bore, the bearing cap can be rotated approximately 45 °, which due to the tips on the teeth of the actuating sleeve , the bearing caps and the grooves of the gearbox housing bore. However, the actuating sleeve cannot twist because it does not leave the area of the grooves, so that an anti-twist device for the actuating sleeve is realized.

According to a further development, a total of 8 grooves can preferably be provided, for example, at a distance of 45 ° on the circumference of the gear housing bore. Of these, e.g. B. 4 grooves allow displacement of the bearing cap 53 and thus also the actuating bolt 51 into a position as shown in FIG. 3. The other 4 grooves can allow the parking lock to be moved into the position shown in FIG. 5.

If the 4 teeth of the bearing cap 53 are within the grooves, which prevent the bearing cap 53 from being displaced to the far left, as shown in FIG. 3, the parking lock is in a disengaged state. In this case, the pawl 55 is not in engagement with the ratchet wheel of the pawl.

If the 4 teeth of the bearing cap 53 are within the grooves, which allow the bearing cap 53 to be shifted to the far left, as shown in FIG. 5, the parking lock is in an inserted state. In this case, the locking wheel of the parking lock is locked by the pawl 55.

In every position of the bearing cap, the spring ensures that the actuating bolt is moved as far as possible to the left until it lies against the end of the bore in the bearing cap. This is particularly shown in Figure 2. In this way, possible tooth-tooth positions of the pawl 55 and the ratchet wheel 57 are avoided. It is particularly advantageous in the design according to the invention that the parking lock is actuated by the shift finger only in one direction.

Another further development of the present invention can provide that the proposed automatically operated parking lock is modified such that an emergency release device is preferably additionally provided. This means that the parking lock can be released as quickly as possible in an emergency.

The parking lock according to the invention can preferably be used in parallel gearboxes (PSG).

A further embodiment of the present invention is described below, in which the simplest possible starting strategy for automatic or automated transmissions is proposed.

The strategies for starting that are already known are relatively complicated and, because of the starting characteristics used, require a relatively large amount of memory. In addition, the characteristic curve for each vehicle type must be adjusted accordingly.

Accordingly, it is an object of the invention to implement a simple strategy for starting which can be used with little effort in different vehicles and which also requires little storage space in the vehicle computer.

As already mentioned, the start-up is currently controlled in EKM and ASG vehicles via start-up characteristics. The transferable target clutch torque T _c ι, _{d is} a function of the engine speed n _e . This follows from the following equation:

r _rf = / («.) (1)

However, it is possible that this strategy is modified at the beginning of the start-up by lowering the desired clutch torque T _c ι, _d below the value calculated in equation 1. In this way, a rapid increase in the desired clutch torque T _c ι, _d and possible stalling of the engine can be avoided become. It can also be provided that at the end of the starting process

Coupling target torque is reduced accordingly to a smooth transition

To achieve clutch sticking.

According to the invention, a control strategy is proposed in which the control unit is able at any time to calculate the torque T * _c ι. The moment T * _c ι is the moment which is transmitted from the clutch immediately after the slip has been reduced. The desired clutch torque T _c ι, d can then preferably be controlled by the following equation: T _{cl, d} = τ; (l + f (n _e -n _g )) (2)

N _g denotes the transmission input speed and f () denotes a monotonically increasing function, the value of which is 0 at f (0). A possible example of such a function can be described as follows:

where k and c are positive constants that can be matched to the respective vehicle. The calculation of T * _c ι will be described later.

The relationship in equation 2 ensures that the desired clutch torque T _c ι, d is greater than the torque T * _c ι as long as the clutch slips. In this way, the slip can be reduced. Equation 2 also ensures that the course of the desired clutch torque T _c ι, _{d is} smooth or steady, that is, there are no jumps in the course of the torque T * _c ι. In this way, the two speeds merge with each other with the same gradients. This avoids a jerky transition from slipping to sticking.

Once the clutch slip n _e - n _g decreases below a predetermined limit, such as 10 U / min can, the starting operation can be considered terminated and the clutch are controlled in the mode "driving"..

The torque to be transmitted T * _C | determined after starting. After starting, the clutch sticks. The engine and transmission are then fixed connected or coupled together. The equation of motion for the motor is then:

J _e -ώ _e = T _e -τ ;,, (4)

where J _{e is} the moment of inertia of the motor, ω- the angular acceleration of the motor and T _{e is} the torque of the motor. The equation of motion for the vehicle is: χ, -ώ _v = τ _r + i - τ, (5)

where J _{v is} the moment of inertia of the vehicle, ω _{v is} the angular acceleration of the vehicle, T _{r is} the sum of all driving resistances of the vehicle and i is the gear ratio of the gear transmitted. Since the engine and the vehicle or the transmission are rigidly connected, the following applies: ώ. X i (6) by inserting equation 6 into equation 5 and by solving for the angular acceleration of the motor ώ _e , an equation for the angular accelerations of the motor ώ _{e can be} given. If the

Angular acceleration of the motor is used in equation 2 and then resolved according to the torque T * _c ι to be transmitted, the following equation results:

With this equation, the torque T * _c ι to be transmitted can be calculated in advance even during the slip phase, since the sum of all driving resistances T _r does not change during the transition from slip to sticking. However, knowledge of the sum of all driving resistances T _{r is} required. As an approximation, the value of T _r can be used during the slip phase, which results from the equation of motion of the vehicle:

T _r = J _v -ώ _v ~ i -T _c! , (8) where T _c ι indicates the torque of the slipping clutch. The value of vehicle acceleration ώ _v can be used to evaluate equation 8.

This can be calculated by differentiating the wheel speed or the transmission input speed (ω _g = i ^■ ω _v ). Overall, there are considerable advantages over the known starting strategy. In particular, in that the desired clutch torque T _c ι, _{d is} a function of the slip speed and not the engine speed. Thus, a single formula for calculating the desired clutch torque T _c ι, d can be used during the entire starting process. Furthermore, no modifications are required for the start and the end of the starting in the starting strategy according to the invention. In addition, the function T _c ι. _d (n _e -n _g ) can be represented in the simplest way. Their adjustment to the respective vehicle can be carried out in the simplest way using one or two parameters. This is particularly time-saving.

To implement the strategy according to the invention, the vehicle acceleration ώ _v should be determined relatively precisely. The wheel speeds supplied by the ABS system can preferably be supplemented by an additional tachometer at the transmission input for determining the vehicle acceleration.

To illustrate the strategy according to the invention presented in FIG

Simulation example shown. The following parameters are preferably used:

J _e = 0.25 kg * m ²

J _v = 70 kg * m ²

T _r = - 5 Nm - 10 Nmh / km * V

Wheel radius = 0.3 m i = 14 k = 0.014min / U c = 0.6

A realistic engine map was used in this simulation. FIG. 6 shows the time profiles of different sizes during the start-up process. The upper diagram shows the engine speed with a dotted line and the speed of the transmission input shaft with a solid line. In the middle diagram, the engine torque is shown with a dotted line and the transferable clutch torque with a solid line. By doing The diagram below shows the vehicle speed with a solid line and the vehicle acceleration with a dotted line. The vertical dashed line which runs through the three diagrams shown shows the

Transition of the clutch from slipping to sticking.

Overall, it can be seen from FIG. 6 that the small jerk in the transition from slip to sticking arises from the fact that the mode was not only switched to after the slip had been completely eliminated, but only when there was a difference between n _e and n _g Value of 10 rpm.

FIG. 7 shows a flow chart which realizes the calculation of the desired clutch torque T _c ι, d during the start-up according to the strategy according to the invention.

A further embodiment of the present invention is described below, in which a strategy is proposed by which in particular the creeping torque is built up more slowly depending on certain consumers and other factors.

A so-called creep function can be implemented in electronic clutch management (EKM) and in automated transmissions (ASG), i.e. the vehicle can crawl as soon as a gear is engaged and the vehicle brake is not applied. Realizing the creep function is relatively complicated because the engine can only provide the idling torque. This creep function is particularly difficult to implement in vehicles with a small cubic capacity, in which precontrol may not be possible, since the engine's speed is limited in such a way that slight loss of comfort is possible. The engine may even stall if the clutch torque builds up too quickly and / or too strongly.

An object of the present invention is to further improve this creep function so that the aforementioned disadvantages from the prior art are avoided. Accordingly, it can be proposed according to the present invention that the

Structure of the clutch torque depending on the consumer, such. B. the air conditioning, the alternator or the like. Is reduced accordingly. The

Speed can e.g. can be varied in several stages. Furthermore, any other function between the consumer and the slope of the ramps can be used to build up the clutch torque. A linear relationship can be particularly advantageous, i.e. the more moment a consumer needs, the flatter the slope of the ramp.

In order to recognize whether a consumer is switched on, the torque signal can preferably be used directly, if available.

It is also possible that digital information, e.g. "Air conditioning switched on" or "Air conditioning switched off" can be used. If the moment signal is not available, a temperature signal or the like can possibly be used, because at a high temperature the air conditioning system is more likely to be switched on.

According to a development of the invention, it can be provided that the slope of the ramp is adapted to previous conditions.

For example, the creep function has stall protection, i.e. if the engine speed falls below a predetermined limit, the clutch is suddenly opened to prevent the engine from stalling. If, for example, this stall protection intervenes several times when the creep function is activated, this can indicate that the clutch was closed too quickly when it crept. For example, the slope of the ramp can be reduced.

In order to implement a long-term adaptation of the slope of the ramp, the value can, for example, be stored in a non-volatile memory or the like (EProm). The driver can perceive an adaptation of the slope of the ramp function by different creeping. However, this represents a lower loss of comfort than the stalling of the vehicle engine. In order to influence the slope of the ramp when the creep torque is built up, the motor does not have to be stalled in an advantageous manner, because the slope of the ramp can be influenced beforehand if the

Clutch control recognizes that the engine is being reduced too much with regard to its engine speed (nMot <nNo idling - offset). It can be useful for the offset

Value can be selected in the range from 0 to 300 rpm. As soon as a reduction in engine speed is detected, the slope of the ramp cannot be influenced as much as when the stall protection is activated, since the reduction in the

Engine speed does not represent a major loss of comfort for the driver.

Overall, the slope of the ramp function when the clutch torque is built up can preferably be influenced if it is recognized in some way that consumers have been switched on. The slope of the ramp can also be influenced if previous conditions of the vehicle, e.g. by intervening in the stall protection, reducing the engine speed or the like.

According to a further embodiment of the present invention, it can be provided that, in addition to influencing the slope of the ramp, e.g. the amount of creep torque is influenced. Here, e.g. the amount of creep torque is preferably reduced, i.e. When the consumers are switched on, the vehicle acceleration has less torque available, so that the maximum creep torque can be adjusted, ie reduced. If, for example, the stall protection has intervened or the engine speed has been greatly reduced, the level of the maximum clutch torque can also be reduced. The reduction can also be carried out in stages or depending on any function.

The proposed strategies can preferably be used in an electronic clutch management (EKM) or an automated manual transmission (ASG). A further embodiment of the invention is described below, in which a strategy is proposed in order to avoid stopping a vehicle on a mountain.

After a certain time, in particular in start-up gears 1, R and 2, the clutch can be pulled in via the path control if, among other things, the following conditions are met: The driver accelerates AND the engine speed n _M ot> 500 AND the transmission input speed nGetπebe> a limit value of the transmission speed n _ge tGrenzwe.t

The limit value of the gearbox speed can be gear and / or country dependent. The limit for the second gear is higher than for the first and the reverse gear. For example, the limit value of the transmission speed can take the sum of the idle speed and 200 rpm, in Brazil, for example, the limit value for the first and reverse gear can take the value that results from the difference between the idle speed and 200 rpm. In Europe, the gearbox speed limit corresponds to the idle speed.

The country dependency with regard to the transmission input speed results, for example, from the fact that diesel vehicles are also used in Europe. In these vehicles, a limit value which is 200 rpm below the idle speed would be disadvantageous since the required oil pressure is not maintained at this speed.

It follows from the aforementioned that, in order to avoid stopping the vehicle on a mountain, it is advantageous if the limit value of the gearbox speed nGet limit value assumes approximately the value 0.

Accordingly, the limit value, the transmission speed nget _G Limit value to the value 0 are set, and in addition the engine speed nmot be monitored. In this way, the clutch is closed more slowly when the vehicle is stopped on the mountain. As a result, the vehicle either starts to move or the engine is pressed accordingly. If the engine falls below a threshold value of e.g. (idle speed - 100 rpm), the clutch can be opened again at a predetermined speed to prevent the engine stalling on the mountain.

The aforementioned conditions can be suitably supplemented and also combined with one another in any way in order to further improve the strategy according to the invention.

This proposed strategy can preferably be used in vehicles with electronic clutch management (EKM), an automated manual transmission (ASG), an uninterruptible manual transmission (USG), a parallel manual transmission (PSG) or the like.

A further embodiment of the present invention is described below, in which undesired acceleration of the vehicle is to be prevented, in particular when driving downhill.

When driving downhill, the vehicle may accelerate faster than the driver requests. If a mountain is very steep, heavy use of the brakes should be avoided to prevent the brakes from overheating. To achieve this goal, a low gear is shifted in both a manual and an automatic transmission, in order to brake the vehicle by the engine and relieve the brakes.

In a vehicle with an electric ESG gearbox, the engine is switched off and the starter generator is used in generator mode in order to use the drive torque of the vehicle to generate electricity. The vehicle can be accelerated on a steep downhill run. This will u. This may not be desired by the driver who, in this situation, wishes to shift into a lower gear in order to use the motor for braking, so that the brakes do not overheat.

In order to avoid the aforementioned disadvantages from the prior art, the starter generator (SG) can be used, in particular in combination with the internal combustion engine (CE) can be used to avoid the unwanted acceleration of the vehicle preferably when driving downhill.

In the case of the electric manual transmission (ESG) in particular, it is advantageous if the vehicle takes countermeasures so that the use of brakes is avoided or reduced. This can e.g. be carried out automatically and / or according to driver requests.

Two different driving situations should be given priority: 1. The vehicle drives down a steep mountain on a narrow road and the

Speed must not increase uncontrollably. It is important that the brakes are not used too much, and it is not necessary to use the brakes in such a way that the vehicle is stopped, only to reduce the speed. At the same time, it would be advantageous if the vehicle were able to utilize or convert the potential energy of the vehicle as much as possible, for example into electrical energy. 2. The vehicle is traveling downhill, but the road is designed in such a way that the driver does not want the speed to be reduced. The vehicle should then react so intelligently that the driver is not confused.

In the first situation, vehicle acceleration should therefore be prevented in any case, and in the second situation vehicle acceleration can be accepted, ie no intervention takes place.

The following countermeasures can therefore be proposed. For example, an increased regeneration of the energy can be provided in order to keep the vehicle acceleration at a predetermined level.

It can further be provided that if the driver perceives the acceleration as too high, a gear is shifted down in order to reduce the acceleration of the vehicle. After receiving the driver's request, the vehicle can select a reverse cruise control mode, which guarantees that the acceleration is kept within certain limits, in particular approximately 0. This can be done, for example, by braking with the starter generator or, if necessary, additionally with the engine.

The latter measure can also be understood as a global measure, which can always be chosen. However, this can cause the vehicle to behave strangely when the driver wishes the potential energy of the vehicle to be used to accelerate the vehicle.

If further acceleration is to be prevented in a driving mode, or if, based on a global strategy, the speed of the vehicle is no longer to be increased when driving downhill, when the accelerator is not being accelerated, or if the driver has selected a downshift, this is necessary that the control system realizes a limitation of the acceleration. A first way can e.g. B. the regeneration of energy e.g. be in generator mode by the starter generator, but if this is not sufficient, the engine can also be started to additionally use the engine brake. Both the engine and the starter generator deliver a negative torque to brake the vehicle. By choosing the right gear in the engine, the negative torque on the engine can be set, the starter generator z. B. picks up a maximum negative moment. An important point is that the combination of the starter generator and the motor makes it possible to set exactly the desired braking torque. This distinguishes the concept according to the invention particularly, since this procedure is not possible with normal automatic transmissions.

In this way, a driver's wish to reduce the speed, which he expresses by pressing the brake pedal, can be realized in that the speed is realized by the combination of engine brake and starter generator regeneration. This can be seen in particular from FIG. 8, in which various moments are shown over time. On the one hand, the desired braking torque is represented by a diamond shape, the engine torque by a square shape and the starter generator torque by a triangular shape. Since these are negative values for the moments shown, these are braking torques. If the driver indicates by accelerating the accelerator pedal that he wants the vehicle to accelerate, the regeneration and the engine braking torque are stopped or switched off. In this way the vehicle can then be accelerated again.

The advantages of the first proposal, in which the regeneration by the starter generator is increased when the vehicle acceleration is to be kept at a predetermined level, are essentially that the use of the brakes is considerably reduced, and the possibility of regenerating energy are given, which would otherwise be lost due to braking. This procedure is particularly advantageous if the vehicle is unable to regenerate energy during braking.

The advantages of the second proposal, which provides both regeneration and an engine brake by downshifting, lie in particular in the better control of the vehicle speed, in particular on steep downhill runs. This proposed system works much more efficiently and reliably than standard solutions in automatic vehicles, in which the transmission is only between shifting between different gears, e.g. can choose between 1st and 2nd or 1st, 2nd and 3rd gear. The problem here is that the acceleration is either too high or too low and the driver has to constantly use the brakes or accelerate to get the vehicle to the right speed.

In contrast to the solution according to the invention, a manual mode is selected in the known method in which a lower gear must be selected.

The second proposal can preferably be used after the driver explicitly requests it; for example, by selecting the driving mode with the gear selector lever or by pressing a button or the like. This can ensure that the driver wants the engine to take over the braking.

A potential problem could arise if the battery is fully charged. Then no further energy should be regenerated in order not to destroy the battery. In order to keep the acceleration of the vehicle constant at a value of about 0, a corresponding use of the braking torques of the starter generator and the

Motor provided. Since the braking torque of the motor can only be carried out in certain steps according to the respective gear, it is particularly advantageous if the electrical energy of the battery is used to make a positive

Moment. Although the vehicle is thereby accelerated, negative braking of the vehicle can be achieved by the engine brake, in particular by selecting an appropriate gear, so that a desired braking torque is also advantageously achieved in this situation, which is derived from the difference from the positive Moment of the starter generator and the negative

Torque of the engine brake results. The acceleration of the vehicle is therefore approximately 0.

In this way, the strategy according to the invention can also be used when the battery is charged. A corresponding diagram showing this procedure is shown in FIG. 9.

There, as in FIG. 8, torque profiles are plotted over time, the diamond profile characterizing the desired braking torque, the square profile the engine braking torque and the triangle profile the positive torque of the starter generator.

FIGS. 10 and 11 show the two proposals according to the invention for preventing undesired acceleration when driving downhill in the form of flow diagrams. FIG. 10 shows the first proposal, which only provides for regeneration by the starter generator. FIG. 11 shows the second proposal, which suggests both regeneration and the engine brake to reduce acceleration of the vehicle.

In particular, the proposed strategy can preferably be used in electric manual transmissions as well as in hybrid vehicles.

The patent claim submitted with the application is a formulation proposal without prejudice for the achievement of further patent protection. The applicant retains to claim further combinations of features previously only disclosed in the description and / or drawing.

Since advantageous developments with regard to the state of the art can form independent inventions on the priority date, the applicant reserves the right to make them the subject of dependent and / or independent claims or division declarations. They can furthermore also contain independent inventions which have a design which is independent of the objects of the previous designs.

The exemplary embodiments are not to be understood as a limitation of the invention. Rather, numerous changes and modifications are possible within the scope of the present disclosure, in particular such variants, elements and combinations and / or materials, which, for example, by combination or modification of individual in conjunction with the described in and in the general description and embodiments and the claim Features or elements or process steps contained in the drawing can be removed by the person skilled in the art with regard to the solution of the task and, by means of combinable features, lead to a new object or to new process steps or process step sequences, also insofar as they relate to manufacturing, testing and working processes.

Claims

claims

1. A method for controlling a drive train of a motor vehicle 1 with an internal combustion engine 2, with a manual transmission 4 and an electrical machine arranged in operative connection with the manual transmission, which by means of at least one

Coupling at least one of the shafts of the manual transmission can be engaged, characterized in that, depending on at least one specific operating state of the motor vehicle, at least one protective measure is carried out to maintain safe and comfortable operation of the motor vehicle.

2. The method according to claim 1, characterized in that the specific operating state of the motor vehicle is present when the motor vehicle 1 is in a downhill descent with the accelerator pedal 40 not actuated and at the same time the acceleration of the motor vehicle is greater than or equal to a predetermined value.

3. The method according to any one of claims 1 or 2, characterized in that as a protective measure, the electrical machine is switched on as a generator, such that the movement of the motor vehicle 1 is delayed and the generator generates electrical energy from the delay of the movement of the motor vehicle and / or under certain conditions the internal combustion engine is switched on via the manual transmission 4 in such a way that the motor vehicle is decelerated.

4. Apparatus for carrying out the method according to claims 1 to 3, comprising a drive train of a motor vehicle 1 with an internal combustion engine and with a manual transmission 4 and an electric machine arranged in operative connection with the manual transmission with at least one rotor and a stator, which by means of at least one Coupling at least one of the shafts of the manual transmission can be activated and with which the motor vehicle can be driven in the connected state or the electrical machine can be activated as a generator and the movement of the vehicle can thereby be delayed and the generator can be used to generate electrical energy recuperatively from the deceleration of the movement of the motor vehicle. Actuating device 50, 50a, 50b, 50c for a motor vehicle transmission automated by means of a transmission actuator 13b, by means of which at least one transmission shaft can be fixed in a certain operating state to block a vehicle movement, characterized in that said actuating device can be actuated by the transmission actuator.