WO2013124130A1

WO2013124130A1 - Method for increasing dynamism and/or torque of an actuator in an actuation device of a motor vehicle, more particularly a transmission or clutch actuation device

Info

Publication number: WO2013124130A1
Application number: PCT/EP2013/051848
Authority: WO
Inventors: Martin Dilzer; Thomas Eckenfels
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2012-02-24
Filing date: 2013-01-31
Publication date: 2013-08-29
Also published as: DE102013201580A1; DE112013001120A5

Abstract

The invention relates to a method for increasing dynamism and/or torque of an actuator in an actuation device of a motor vehicle, more particularly a transmission or clutch actuation device, in which the actuator is supplied by a vehicle voltage supply. In order to continue to meet the high requirements relating to actuator dynamics without conflicts arising in the engine design, the motor vehicle is monitored with regard to critical driving situations and in the event that a critical driving situation is detected, the vehicle voltage supply is increased in order to improve actuator activity.

Description

Method for increasing a dynamic and / or torque of an actuator in an actuating device of a motor vehicle, in particular a transmission or

Clutch actuator

The invention relates to a method for increasing a dynamic and / or torque of an actuator in an actuating device of a motor vehicle, in particular a transmission or clutch actuator, in which the actuator is supplied with a vehicle electrical system voltage.

Automated friction clutches in a drive train of a motor vehicle between a drive unit, for example an internal combustion engine, an electric motor or a hybrid arrangement of both, and a transmission train are well known from series applications. In this case, DE 101 59 267 A1, for example, discloses a method for controlling the same, in which a so-called torque tracking is effective. This means that the friction clutch is only closed so far that the engine torque is transmitted to the drive unit. This means that the friction clutch can be operated with reduced actuation paths during switching operations of the transmission and therefore can be controlled quickly and spontaneously. Furthermore, rotational and uniformity of the drive unit can be filtered by means of a set micro-slip. In order to reduce the disengagement and holding forces of the friction clutch, in particular when pushed back friction clutches, self-locking clutch actuators are used, which are energized only when a request for a change in the clutch torque. However, it has been shown that during a torque update, the clutch torque is regulated frequently and thus self-locking clutch actuators have a high energy consumption.

Hybrid and electric vehicles have a high-voltage energy storage, which supplies them with energy. As a result, eliminates the alternator, since the 12-volt electrical system is operated via a DC / DC converter directly from the high-voltage energy storage. For actuators with DC motors, which are connected to the vehicle electrical system, this means a limited power consumption. The limited power consumption results because the maximum current in the output stages of control units limited and the voltage in the electrical system is limited to 12 volts. Due to constantly increasing demands on the actuator dynamics, conflicting goals result in the design of the DC motor of the actuator. As can be seen from FIG. 1, if a large value is placed on a high torque M at low speed n of the DC motor (high motor constant K _t, i), the dynamics are lost at high rotational speeds of the DC motor, as well as vice versa (small motor constant K _{t 2} ).

The invention is therefore based on the object of specifying a method for increasing the actuator dynamics and / or the actuator torque, in which the increasing demands on the actuator dynamics is carried without conflicts in the engine design occur.

According to the invention the object is achieved in that the motor vehicle is monitored for critical driving situations and when detecting a critical driving situation, the vehicle electrical system voltage is increased to improve the Aktoraktivität. By increasing the voltage in the electrical system of a hybrid or electric motor vehicle both the dynamics and the torque of the actuator is improved in the actuator of the motor vehicle. As a result, a rapid response of the actuator to the critical driving situation is possible, whereby the critical driving situation can be overcome in a timely manner.

Advantageously, the vehicle electrical system voltage is briefly increased. In many cases, it is sufficient that the vehicle electrical system voltage is only increased until the critical situation is overcome. After overcoming this critical situation, the electrical system is reduced back to the usual 12 volts and continued the normal driving of the motor vehicle.

In one embodiment, the vehicle electrical system voltage from a, for the operation of a

Electric motor provided for driving the motor vehicle provided high-voltage. This has the advantage that the alternator, which normally provides the vehicle electrical system voltage in motor vehicles during operation of the motor vehicle with an internal combustion engine, can be dispensed with. Due to the omission of the alternator not only space in the engine compartment of the motor vehicle is saved, but also a cost-effective solution in the generation of two voltage networks, once the vehicle electrical system voltage of about 12 volts and the high-voltage voltage of approximately 230 volts provided.

In one variant, a voltage converter connected to the high-voltage voltage generates the vehicle electrical system voltage from the high-voltage voltage and increases, as a result of a signal, which When the critical driving situation is detected by a control unit, the vehicle electrical system voltage is output. Voltage transformers which derive the vehicle electrical system voltage from a high-voltage voltage are well known, which is why an application of such voltage transformers represents a particularly cost-effective solution.

In a further development, the critical driving situation requiring the increase of the vehicle electrical system voltage is a dynamically critical driving situation or a driving situation with increased demand on the torque to be transmitted by the actuator. Both the dynamics and the torque of the actuator can be increased by increasing the vehicle electrical system voltage to overcome the critical driving situation.

In one embodiment, the vehicle electrical system voltage is increased when a highly dynamic actuation of the actuator is required. As a result, the critical driving situation is overcome as quickly as possible.

Advantageously, the vehicle electrical system voltage is increased when an increase in the maximum torque of the actuator, preferably at a speed close to zero, is necessary, in particular, a current limit of the torque of the actuator is overcome. The increase in the vehicle electrical system voltage is always made specifically when a voltage increase to improve the activity of the actuator is necessary.

In particular, a sluggishness of the actuator at low temperatures is overcome by increasing the vehicle electrical system voltage. Due to this design, the actuator remains functional even in those operating situations in which this would be only partially operable at a vehicle electrical system voltage of 12 volts.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

Show it

Figure 1: a torque-speed diagram according to the prior art

Figure 2: a schematic representation of the communication of control devices in one

motor vehicle Figure 3: a torque-speed diagram at elevated vehicle electrical system voltage.

In Figure 2 is a schematic diagram of the communication of control devices in one

Motor vehicle shown, as it finds particular application in motor vehicles, which are designed as electric or hybrid vehicles. In electric vehicles, the motor vehicle is driven only by the electric motor, while in a hybrid vehicle, it is possible that the motor vehicle is driven by an internal combustion engine and / or an electric motor.

In such a motor vehicle, a control device architecture 1 is present, in which a higher-level control unit 2 exchanges information and data via a communication interface 3 with various decentralized control devices. In the present case, the actuator control unit 4 and the voltage converter control unit 5 are considered as decentralized control units. The actuator control unit 4 can be used in a clutch actuation system of the motor vehicle, wherein the actuator is a DC motor driving a clutch 6 (DC motor) whose output stages are arranged in the actuator control unit 4. The DC motor 6 itself is fixed outside of the actuator control unit 4 to the clutch, not shown.

The voltage converter control unit 5 leads to a DC / DC converter 7 which is connected to a high-voltage battery, not shown, which supplies the electric motor provided for driving the vehicle with energy so that it can drive the motor vehicle. Such a high-voltage battery preferably has a voltage of 230 volts. The DC / DC converter 7 now converts this 230 volts to the level of the vehicle electrical system voltage, which is generally 12 volts in the motor vehicle. With this vehicle electrical system voltage of 12 volts and the output stages of the DC motor 6 are supplied, which is arranged in the actuator control unit 4.

The higher-level control unit 2 monitors the motor vehicle for critical

Driving situations. As critical driving situations in which high dynamics of the DC motor 6 is required, for example, the closing of the clutch for towing the engine or the start of a reference point of the clutch during activation of the actuator system or performing a service function of the clutch during normal operation are considered , If such a critical driving situation occurs, in which the clutch of the motor vehicle must be actuated as quickly as possible, sends the über- ordered controller 2 to the voltage converter control unit 5, a signal to increase the vehicle electrical system voltage. The DC / DC converter 7 is controlled by the voltage converter control unit 5 and generates from the high-voltage voltage a vehicle electrical system voltage of 14 volts, which allows the DC motor 6 to act with a higher dynamics and / or higher torque to the clutch as possible quickly move to the desired position. Thus, in highly dynamic operation of the DC motor 6, especially in the high speed range, improved engine dynamics achieved without having to compromise.

As can be seen from FIG. 3, an increase in the vehicle electrical system voltage of the DC motor 6 results in a parallel displacement of the limit characteristic curve at a fixed motor constant K _t . As a result, both a higher torque M near a speed n of zero is achieved at an increased vehicle electrical system voltage. Furthermore, after the startup of the torque M, the DC motor 6 reaches a speed which exceeds the speed n, which the EC motor 6 can set at a vehicle electrical system voltage of 12 volts maximum.

Furthermore, it can be seen from FIG. 3 that, given a clever design of the EC motor 6, it is possible to increase the maximum torque M of the DC motor 6 at a speed n = 0. For this purpose, the DC motor 6 is designed so that the voltage and not the current limits the maximum torque M in this speed range. This can be seen in particular in comparison with Figure 1, where the torque M is limited to a constant by limiting the current at low speeds. This is successfully prevented by the described method.

Due to the statements made the ever-increasing demands on the actuator dynamics is taken into account and goal conflicts in the engine design, such as high torque M at low speeds n, the dynamics of the EC motor 6 is lost at high speeds n, and vice versa a small torque M. at high speeds n, where the torques M are reduced, overcome. List of Reference Numerals a. Control device architecture

b. Parent control unit

c. Communication Interface

d. actuator control

e. DC converter controller

f. DC motor

g DC / DC converter

M torque

n speed

Claims

claims

1 . Method for increasing a dynamics and / or a torque of an actuator in an actuating device of a motor vehicle, in particular a transmission or clutch actuator, in which the actuator (6) is supplied with a vehicle electrical system voltage, characterized in that the motor vehicle is monitored for critical driving situations and upon detection of a critical driving situation, the vehicle electrical system voltage is increased to improve the actuator activity.

2. The method according to claim 1, characterized in that the vehicle electrical system voltage is increased briefly.

3. The method according to claim 1 or 2, characterized in that the vehicle electrical system voltage is obtained from a, provided for the operation of an electric motor for driving the motor vehicle high-voltage.

4. The method according to claim 3, characterized in that a high voltage connected to the voltage converter (7) generates the vehicle electrical system voltage from the high voltage and due to a signal which is output upon detection of a critical driving situation by a control unit (2), the vehicle electrical system voltage increases.

5. The method according to at least one of the preceding claims, characterized in that the increase of the vehicle electrical system voltage requiring critical driving situation is a dynamic-critical driving situation or a driving situation with increased demand on, by the actuator (6) to be transmitted torque (M).

6. The method according to claim 5, characterized in that the vehicle electrical system voltage is increased when a highly dynamic actuation of the actuator (6) is required.

7. The method according to claim 5, characterized in that the vehicle electrical system voltage is increased when an increase of the maximum torque (M) of the actuator (6), vorzugswei- se at a speed (n) near zero, is necessary, in particular, a current limit of the torque (M) of the actuator (6) is overcome.

8. The method according to claim 7, characterized in that a Schwergangigkeit of the actuator (6) is overcome at low temperatures.