DE102014215263A1 - A method for maintaining a safe driving condition of a motor vehicle by an actuator and a control unit - Google Patents

Abstract

The invention relates to a method for maintaining a safe driving condition of a motor vehicle by an actuator, which is controlled by a control unit (1), wherein the control unit (1) via a current-carrying supply line (6) is connected to an external power supply and the voltage on the Supply line (6) is measured, wherein upon detection of an undervoltage on the supply line (6), a second current-carrying line (19) for supplying the control unit (1) is activated. In a method in which constructive and cost expenditures are reduced, a current-carrying line (19) present in the motor vehicle is used as the second current-carrying line for supplying a logic module (5) contained in the control unit (1) to an emergency running state of the motor vehicle to sustain permanently.

Description

The invention relates to a method for maintaining a safe driving state of a motor vehicle by an actuator according to the preamble of claim 1 and a control device for carrying out the method according to the preamble of claim 4.

The invention relates to a method for maintaining a safe driving condition of a motor vehicle by an actuator, which is controlled by a control unit, wherein the control unit is connected via a current-carrying supply line to an external power supply and the voltage is measured on the supply line, wherein upon detection of an undervoltage on the supply line, a second current-carrying line for supplying the control unit is activated, and a control device for carrying out the method.

Such a control unit can be used for example in an automated manual transmission in a motor vehicle. The automated manual transmission may be, for example, a parallel-shift transmission (PSG) - also referred to as a dual-clutch transmission - with two sub-drive trains, each with a partial transmission with multiple, switchable by one or more gear actuators gears, each sub-drive train is assigned a friction clutch, the operated by a clutch actuator ( DE 10 2008 050 289 A1 ). The involved gear actuators and clutch actuators are controlled by one or more of the control devices according to the invention. The actuation is controlled by a control unit by means of a control and driver unit.

The control devices according to the invention are also provided for fail-safe control of other electrically operated actuators, for example for controlling clutch and / or transmission actuators in automated clutch systems, for example in EKM systems (electronic clutch management), clutch-by-wire systems and all types of automated Manual transmissions (ASG, PSG). Furthermore, these control units for fail-safe operation of the actuators of separating clutches in hybrid vehicles and for operating parking brake actuators in motor vehicles and for controlling other actuators in the motor vehicle, such as actuators for actuating switching elements in the drive train of a motor vehicle, such as claw couplings, provided ,

The control unit is supplied with electrical energy from an external energy source by means of a first current-carrying line. In order to prevent the power supply of the control unit from failing in the event of a line break, fuse blow-out or dropping of the plug, a second current-carrying lead is additionally present in parallel with the first current-carrying line Provide line that is automatically switched on when the first line is interrupted.

In addition, it is known that the described automated drive systems must switch temporarily and permanently in the failure of the power supply in a designated as brake mode emergency mode, in which the control unit arranged power transistors shorted in the ground path and the power transistors connected in the current path must be closed high resistance or the other way around. To sustain this brake mode permanently, an energy storage device is available.

The disadvantage here is that the brake mode can not be maintained permanently, since the energy storage has only a limited capacity. However, a permanent maintenance of the brake mode is particularly important if, for example, a clutch against the clutch force must be kept in a certain position in order to maintain a driving condition of the motor vehicle and to avoid accidents.

The invention is thus based on the object of specifying a method for maintaining a safe driving state of a motor vehicle by an actuator, in which the driving state is maintained even with interruption of a power supply line with an external power supply.

According to the invention, the object is achieved in that as a second current-carrying line for supplying a, contained in the control unit logic module in the motor vehicle itself existing current-carrying line is used to keep the emergency condition of the motor vehicle permanently upright. By using a self-existing current-carrying line eliminates the installation of an additional electrical power supply line. As a result, the structure of the control unit is simplified and still allows sustained maintenance of the driving condition of the motor vehicle, since the logic module, which is of particular importance for the activation of the actuator, is put into such a state by the current-carrying line present in the motor vehicle the driving condition of the motor vehicle remains unchanged and dangerous situations are prevented. Another advantage of such, even in a power failure active logic module is the ease of diagnostics and the ability to continue with others Control devices to thereby initiate possibly vehicle reactions such as engine intervention or engine shutdown and / or to warn the driver.

Advantageously, as an existing in the motor vehicle current-carrying line lying on battery plus ignition or vehicle ground is used, which allow the supply of the logic module delay and permanently in case of failure of the control unit supply.

In one embodiment, the logic module switches after the detection of the undervoltage on the current-carrying supply line, the motor vehicle via a clutch actuator permanently in a brake mode in which a clutch of the motor vehicle is maintained at a level which this upon detection of undervoltage on the current-carrying supply line Control unit has taken. By this simple method, a closing of the clutch against the coupling force is prevented or slowed down, whereby dangerous situations for the motor vehicle and its occupants are prevented. Slow clutch closure can be tolerated if other safety-related vehicle responses, such as driver warning and engine intervention, are made over time. On a separate energy storage for the logic module can be omitted.

A development of the invention relates to a control device for controlling an actuator, wherein the control device is connected to an external power supply by means of a current-carrying supply line, and a second current-carrying line is present, which is switchable or automatically usable upon detection of an undervoltage on the current-carrying supply line. In a control device, which maintains the actuator in case of failure of the power supply via the first current-carrying supply line in the current driving state, is used as a second current-carrying line for supplying a logic module in the motor vehicle itself existing live line to the driving condition, preferably an emergency condition, to maintain the motor vehicle permanently. This is a particularly cost-effective and structurally advantageous method, as can be dispensed with the arrangement of additional redundant current-carrying lines in or on the control unit. The still active logic module is easy to diagnose, for example via the CAN bus of the motor vehicle, and there remain possibilities that the control unit can communicate with other control units of the motor vehicle. In particular, when the fault is detected, vehicle reactions may be triggered by other control devices, such as engine intervention or engine shutdown, or driver warning.

Advantageously, the logic module is connected to a lying on battery plus ignition or vehicle ground. Since these two lines are present per se in the motor vehicle, they can be easily connected to the controller and in the controller to the logic module to maintain the logic module in the activated state.

In one embodiment, a Verpolschutzelement is arranged in the ignition. This polarity reversal protection element can be formed in the simplest case as a diode. By a further diode can be prevented that in case of failure of the power supply line of the control unit, the ignition connected to the battery plus ignition line is overloaded. In a simple variant, the further diode is to be designed as a germanium diode and the polarity reversal protection diode on the current-carrying supply line is a silicon diode in order to allow the current across the ignition to approach zero due to different voltage drops across the two diodes.

In a further variant, a current limiting element, preferably a resistor or a transistor circuit, is arranged in the ignition line. This is always important if the current limit in normal operation, caused by the different diodes - because the other diode has a lower voltage drop than the polarity reversal diode - is not sufficient and additional security is to be created.

In a further embodiment, the logic module is connected to the vehicle ground via a housing of the control unit. This is an extension to have a second ground supply for the logic part even in case of failure of belonging to the power supply line ground line (terminal 31).

Furthermore, a further reverse polarity protection element and / or a further current limiting element are arranged in the connection with the vehicle ground. The polarity reversal protection of the housing is necessary if the housing is also to be protected against reverse polarity. Similar to the ignition cable and the connection to vehicle mass via the control unit Chasis, are running current limited. The current limit both on ground and on the supply side (ignition cable) is such that at maximum logic current a maximum voltage drop is not exceeded. Thus, in the case of emergency operation, the emergency supply via the housing ground is quite permissible.

In one embodiment, a plug connection is formed for connecting the ignition line and / or the vehicle ground.

A further development of the invention relates to a control device for controlling an actuator, wherein the control device is connected to an external power supply by means of a current-carrying supply line and the power line associated ground line and a second ground line is present, which in case of disturbance of, the current-carrying line associated ground line switchable or automatically usable. In a control device which maintains the actuator in case of failure of the power supply via the ground line in the instantaneous driving state is used as a second ground line to power a logic module, in the motor vehicle inherent mass, preferably the housing ground of the controller to the driving condition, preferably one Run-flat state, to maintain the motor vehicle permanently. This is a particularly cost-effective and structurally advantageous method, as can be dispensed with the arrangement of additional redundant current-carrying lines in or on the control unit.

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

It shows:

1 an embodiment of a control device according to the invention.

According to 1 operates the control unit 1 a, several electric motors comprehensive actuator 2 for actuating a, two friction clutches containing parallel shift transmission. The components and lines for controlling and powering the actuator are omitted for clarity. Only a driver 3 and a power amp 4 are shown schematically. A logic module 5 in the form of a microprocessor, which is located at the terminal GND, takes over the control and computing operations of the control unit 1 ,

The control unit 1 is by means of a first current-carrying line 6 to the electrical system of the motor vehicle, in particular the so-called "terminal 30" (input Battery Plus), connected. The first current-carrying line 6 belonging ground line 7 is connected to the so-called "terminal 31" (return to battery negative or ground). By means of these lines 6 . 7 becomes the controller 1 energized. The live line 6 is secured by a fuse F1. Behind the respective entrance 8th . 9 of the control unit 1 is for each line 6 . 7 one shunt resistor each 10 . 11 intended. In the present example, the shunt resistor 10 the first live line 6 from a comparator 12 bridged.

In the line 7 is before the shunt resistor 11 a polarity reversal protection 13 arranged, with the shunt resistor 11 from a second comparator 14 is bridged. The live line 7 is on a housing 15 of the control unit 1 connected, which is also a current limiting element in the form of a shunt resistor 16 and a polarity reversal protection element 17 having. Due to the arrangement on the housing 15 is the ground line 7 on vehicle mass.

The live line 6 is via a logic supply 18 with the logic module 5 connected to the logic supply 18 also an ignition cable 19 connected. The ignition cable 19 of the motor vehicle is as a terminal 15 and is connected to battery plus. By means of this ignition cable 19 not just the logic module 5 but also the driver 3 energized when the power supply to the line 6 is interrupted. In the ignition cable 19 are a polarity reversal protection 20 and optionally a current limiting element 21 arranged.

The trained as a microprocessor logic module 5 is about the driver 3 with the power amplifier 4 connected to the actuator 2 , in particular the electric motors drives. In addition, there is a trained as a watchdog circuit monitoring circuit 22 which interrelates with the logic module 5 stands. Because the control unit 1 for the logic module 5 another connecting line (ignition cable 19 ), the logic module 5 even if there are faults in the live line 6 of the control unit 1 be operated independently. Alternative to the ignition cable 19 and the housing ground 15 , which are the current-carrying line 6 belonging ground line 7 replaced, but can also be a second supply path via a separate plug to the controller 1 be guided.

In the normal state, the controller 1 with the ignition switched on via the live cables 6 . 7 connected to the battery of the motor vehicle. The ignition cable 19 lies on battery plus and the control unit 1 is over the case 15 connected to the vehicle mass. The condition of the pipes 6 . 7 including the fuse F1 is about the voltage drop across the shunt resistor 10 . 11 checked. The comparator 12 measures the tension, which is before the shunt resistance 10 and which after the shunt resistance 10 in the first live line 6 is applied. There is no interruption on the first live line 6 before, so will the comparator 12 a Difference> 0 in the voltages before and after the shunt resistor 10 detect. But if a line break, a failure of the fuse F1 or a plug failure has occurred, then the comparator 12 no voltage difference from the voltages before and after the shunt resistor 10 detect. The comparator 12 transmits its measurement results to the input A / D1 of the logic module 5 ,

Alternatively, it is also conceivable that instead of the shunt resistor 10 the voltage drop across a polarity reversal protection is measured. The ground line 7 is in the same way with the second comparator 14 Checks the voltage before and behind the shunt resistor 11 measures and reports its measurement results to input A / D2 of the logic module.

In case of failure of the supply line 6 is the ignition cable 19 automatically via the logic supply 18 available. Diode D1 prevents failure of the live line 6 or the fuse F1 the ignition cable 19 overloaded. The current limit of the ignition cable 19 is optional. It must be ensured that a minimum current for maintaining the logic supply can be provided without significant voltage drop in the event of a fault.

Because the control unit 1 low resistance to the housing 15 and thus also the vehicle mass is connected, must also the ground line 7 be protected against reverse polarity. The reverse polarity protection of the housing 15 again, it is only necessary if the case too 15 protected against reverse polarity.

Once the microprocessor 5 via its inputs A / D1 or A / D2 detects no defined voltage drop, the electric motors of the actuator 2 switched off and initiated a brake mode. The status is communicated to other control units via a CAN bus (not shown). Thus, in the presence of a fault in the supply lines 6 and or 7 an emergency run possible. The driver 3 as well as the logic module 5 , continues to be supplied with power and is thus also able to switch the brake mode permanently and at short notice. In the context of the parallel shift transmission this means that the clutch is held by the brake mode in the state which it is in the case of detection of the power interruption in the line 6 or 7 has taken.

In another variant, in the event of a fault, the logic module embodied as a microprocessor 5 via the monitoring circuit 22 resetet, which means that the outputs of the microprocessor 5 are high impedance. The brake mode is controlled by a defined resistor circuit at the input of the driver 3 (Pull-up / pull-down) brought about. In this case, the diagnosis and thus the function of the switches DIAG1, DIAG2 and the readback line DIAG _{power amplifier must be} directly via the monitoring circuit 22 respectively.

In a further variant, the power transistors of the final stage 4 directly to the actuator 2 , so behind the output of the driver 3 , switched. It must be ensured that the driver goes to Disable and that its outputs are high-impedance. This disable switching of the driver and the readback of the power amplifier 4 can through the microprocessor 5 and / or by the monitoring circuit 22 respectively.

It is also possible that the error case and the subsequent setting of a safe state, a brake mode, be simulated. It is via the switch DIAG1 of the microprocessor 5 the error case fault on the line 6 and / or fuse F1 defective simulated. The desired function of switch DIAG1 may be via the reduced voltage drop across the shunt resistor 10 be diagnosed via the input A / D1.

The DIAG2 switch causes a fault in the ground line 7 simulated. Switching off the reverse polarity protection reduces the current flow in the shunt resistor 11 the ground line 7 , By the voltage measurement via A / D2 the diagnosis is given. The state of the brake mode can be reached via the lines DIAG _{power amplifier} from the microprocessor 5 and / or diagnosed by the monitoring computer.

The explained solution has the advantage that no additional external supply lines are necessary, but the already existing supply lines (ignition line and housing ground line) are used.

LIST OF REFERENCE NUMBERS

1

 control unit

2

 actuator

3

 driver

4

 final stage

5

 logic module

6

 Power line

7

 ground line

8th

 Input of the control unit

9

 Input of the control unit

10

 Shunt resistor

11

 Shunt resistor

12

 comparator

13

 Reverse polarity protection

14

 comparator

15

 Frame ground

16

 Shunt resistor

17

 Verpolschutzelement

18

 logic supply

19

 Ignition

20

 Reverse polarity protection

21

 Current limiting element

22

 monitoring circuit

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

• DE 102008050289 A1 [0003]

Claims (10)

Method for maintaining a safe driving condition of a motor vehicle by an actuator, which is controlled by a control unit ( 1 ) is controlled, wherein the control unit ( 1 ) via a live supply line ( 6 ) is connected to an external power supply and the voltage on the supply line ( 6 ), wherein upon detection of an undervoltage on the supply line ( 6 ) a second current-carrying line ( 19 ) for the supply of the control unit ( 1 ) is activated, characterized in that as a second current-carrying line for supplying a, in the control unit ( 1 ) contained logic module ( 5 ) a self-contained in the motor vehicle current-carrying line ( 19 ) is used to sustain a runflat condition of the motor vehicle permanently. A method according to claim 1, characterized in that as an inherent in the motor vehicle current-carrying line lying on a battery plus ignition ( 19 ) or a vehicle mass is used. Method according to claim 1 or 2, characterized in that the control unit ( 1 ) after the detection of the undervoltage on the current-carrying supply line ( 6 ) the motor vehicle via a clutch actuator ( 2 ) permanently in a brake mode, in which a clutch of the motor vehicle is maintained at a level which this upon detection of undervoltage on the current-carrying supply line ( 6 ) has taken. Control unit for controlling an actuator, wherein the control unit ( 1 ) with an external power supply by means of a current-carrying supply line ( 6 ) and a second live line ( 19 ), which upon detection of an undervoltage on the current-carrying supply line ( 6 ) is switchable or automatically usable, characterized in that as a second current-carrying line for supplying a logic module ( 5 ), in the motor vehicle itself present current-carrying line ( 19 ) is used to permanently maintain the driving condition, preferably an emergency running condition, of the motor vehicle. Control device according to claim 4, characterized in that the logic module ( 5 ) with a battery lead plus ignition lead ( 19 ) or a vehicle mass is connected. Control device according to claim 5, characterized in that in the ignition line ( 19 ) a reverse polarity protection element ( 20 ) is arranged. Control device according to claim 5 or 6, characterized in that in the ignition line ( 19 ) a current limiting element ( 21 ), preferably a resistor or a transistor circuit is arranged. Control device according to one of Claims 5, 6 or 7, characterized in that the logic module ( 5 ) with the vehicle mass via a housing ( 15 ) of the control unit ( 1 ) connected is. Control device according to claim 8, characterized in that the connection with vehicle mass another polarity reversal protection element ( 17 ) and / or has a further current limiting element. Control unit for controlling an actuator, wherein the control unit ( 1 ) with an external power supply by means of a current-carrying supply line ( 6 ) and one of the current-carrying line ( 6 ) associated with ground line ( 7 ) and a second ground line ( 15 ), which in case of failure of the, the power line ( 6 ) associated with ground line ( 7 ) is switchable or automatically usable, characterized in that as a second ground line for supplying a logic module ( 5 ) a mass inherent in the motor vehicle ( 15 ), preferably the housing mass ( 15 ) of the control unit ( 1 ) is used to permanently maintain the driving condition, preferably an emergency running condition, of the motor vehicle.

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