DE102006059664A1 - Motor vehicle drive train, has turbocharger pressure determining device and reference signal generator connected with actuating device for supplying current to electric motor during occurrence of turbo lag - Google Patents

Abstract

A motor vehicle drive train has an internal combustion engine and an electric motor which can be connected to a battery via a drive device as a drive. The internal combustion engine and / or the electric motor can be brought into drive connection with an output shaft via a dual-clutch transmission. The internal combustion engine has to change its speed and / or its torque connected to a setpoint generator actuator. The internal combustion engine has an exhaust gas turbocharger and a device for determining its charge pressure. The device for determining the boost pressure and the setpoint signal generator are in energized control of the electric motor when a turbo lag occurs with the drive device.

Description

The The invention relates to a motor vehicle drive train comprising an internal combustion engine and having an electric motor as a drive, wherein the electric motor via a Control device can be connected to a battery, wherein the Combustion engine and / or the electric motor via a dual-clutch transmission can be brought into driving connection with an output shaft, and wherein the internal combustion engine for changing its speed and / or its torque connected to a desired signal generator actuator having.

One such powertrain is from the book "7. LuK Colloquium 11./12. April 2002 ", publisher: LuK GmbH & Co., Buehl / Baden, DE, pages 251-258 known. The dual-clutch transmission has a first and a second Partial transmission, each over a gear with an output shaft are connectable. An input shaft of the first sub-transmission is over a first clutch and an input shaft of the second sub-transmission via a second coupling coupled to a drive shaft of an internal combustion engine. The electric motor is on the input shaft of the second partial transmission arranged and over the second clutch can be connected to the drive shaft. To drive of the motor vehicle with the internal combustion engine is in the corridors of first part of the first clutch closed. This is a Driving torque from the drive shaft of the internal combustion engine via the first clutch and the first partial transmission transmitted to the output shaft. The second partial transmission is located depending on the shift strategy in neutral position or a gear is selected. If the second part transmission is arranged in neutral position, the second clutch is closed, to couple the electric motor to the drive shaft. If at the second part of a gear is preselected, is the second clutch open, so that the electric motor over the preselected Gear, the output shaft, the first partial transmission and the first clutch is coupled to the drive shaft. During the combustion engine Driving the electric motor can be operated as a generator to to charge the battery. In this case, a recovery of braking energy is possible. By Reversal of the torque direction, the electric motor can take over a booster function, at He supports the combustion engine as an additional drive. Corresponding the large installed Power of the electric motor and the battery can be the motor vehicle be driven only with the electric motor.

there Both clutches are open and the drive torque is over one of the aisles of the first sub-transmission transmitted to the output shaft. Opposite one Powertrain, in which the motor vehicle driven only by an internal combustion engine becomes possible the powertrain with that from the combustion engine and the Electric motor existing hybrid drive significantly reduced Fuel consumption.

In the magazine mot, issue 10/2004, pages 1 to 5 is further proposed a generic driveline, which is an internal combustion engine with Has exhaust gas turbocharger and a starter generator. The starter generator has a permanent-magnet synchronous machine, which is located between the internal combustion engine and one with this over a hydraulic torque converter coupled automatic transmission is arranged. When starting the motor vehicle, the starter generator switched as an electric motor to a larger drive torque to reach. This will cause the occurring at low speeds Turbo hole of the internal combustion engine at least partially compensated. The Although equipped with the exhaust gas turbocharger internal combustion engine has a low power to weight ratio, but has compared to a larger displacement, not charged naturally aspirated engine of corresponding power in certain operating conditions relatively low torque.

It There is therefore the task of a drive train of the aforementioned Art to create, despite compact dimensions and high torque and a high power output allows.

These Task is solved by that the internal combustion engine is an exhaust gas turbocharger and a device to determine the boost pressure, and that the device for determining the boost pressure and the setpoint signal generator for energizing the electric motor when a turbo lag with the drive device is in control connection.

In an advantageous manner, this makes it possible to detect the occurrence of a turbo lag, ie an operating state of the internal combustion engine in which the torque output by the latter is lower than a desired torque requested via the desired signal generator, based on the charge pressure and a desired signal predetermined by the desired signal generator Occurrence of such a turbo lag with the aid of the electric motor to generate an additional drive torque and transmitted via the dual-clutch gearbox to the output shaft. In this case, the electric motor is preferably controlled such that the sum of the torques of the internal combustion engine and the electric motor approximately corresponds to the requested target torque. Thus, the turbo lag can be compensated not only when starting but also while driving, for example, when the motor vehicle at a low engine speed be should be accelerated.

at an embodiment The invention comprises the device for determining the boost pressure at least one pressure sensor, the downstream of the exhaust gas turbocharger preferably in an air supply duct for the Combustion engine is arranged. The boost pressure and the occurrence of a Turbo holes can then be determined very precisely.

at an advantageous embodiment of the invention, the internal combustion engine an engine control unit in which the device to determine the boost pressure at least is partially integrated, the dual-clutch transmission a with clutch actuators and / or at least one actuator for actuating a Has switching device connected dual-clutch transmission control unit, and the engine control unit for transmission a boost pressure signal to the dual clutch transmission control unit with this connected is. Thus, the existing in the engine control unit information about the charge pressure to control the electric motor be shared.

at a preferred embodiment The invention is a device for detecting a speed signal for the Intended combustion engine provided, wherein the desired signal generator and the Device for detecting the speed signal with the device connected to the determination of the boost pressure, and wherein the device for determining the charge pressure for the pressure sensorless determination of Boost pressure from the speed signal and a desired signal of the setpoint signal generator has a data memory in which parameters are stored, each one Speed value and a desired signal value, a value for the stationary boost pressure assign the exhaust gas turbocharger. The boost pressure is thus indirectly detected signals. Thus, a more expensive and expensive pressure sensor for the Measurement of the boost pressure can be saved. The parameters can be found in Form of at least one characteristic and / or in the form of one from a Number of value combinations existing map stored in the data memory be.

at an expedient embodiment of the Invention has the device for determining the boost pressure first comparison means for comparing the speed signal with a predetermined speed signal threshold and / or for comparison the desired signal with a predetermined setpoint signal threshold, wherein the first comparison means an output for a first Comparative signal has, with an input of a filter device connected to the formation of a moving average signal is formed from the first comparison signal, wherein an output the filter means for comparing the moving average signal with a predetermined threshold with an input of a second one Comparative device is connected, and wherein the second comparison means such is in control connection with the drive means that the Electric motor depending on one outputable at an output of the second comparison device second comparison signal is driven. The can Comparative devices and the filter device also in the form of a Operational program realized on a microcomputer of the Dual clutch transmission control unit expires.

Advantageous is when the dual-clutch transmission has a first input shaft and has a second input shaft, each with at least one gear the output shaft are connectable when the first input shaft via a first clutch and the second input shaft via a second clutch with a drive shaft of the internal combustion engine can be coupled, and when the electric motor so in drive connection with the second input shaft is that he over the second clutch can be coupled to the drive shaft. The motor vehicle powertrain allows then a particularly compact design.

following is an embodiment closer to the invention explained. Show it:

1 a schematic representation of a motor vehicle drive train and

2 a flowchart for a part of an operating program, which is provided for detecting a turbo lag.

An in 1 shown schematically, as a whole with 11 designated motor vehicle drive train has a combustion engine designed as a reciprocating engine 12 and an electric motor 13 as a drive on, via a dual-clutch transmission 14 with an output shaft 15 can be brought into drive connection.

The combustion engine 12 has an exhaust gas turbocharger 16 in the manner known per se one of the exhaust gas flow of the internal combustion engine 12 driven first turbine wheel 17 having that with a second turbine wheel 18 is in driving connection, which is arranged in an air intake duct, with the inlet openings of combustion chambers 19 the combustion engine 12 connected is. The combustion engine 12 also has a desired signal generator 11 , such as a load lever or an accelerator pedal, with which a target signal for adjusting the operating point (torque, speed) of the internal combustion engine 2 can be specified. The desired signal generator 10 is via an engine control unit 21 with a Stell element 22 connected to the air and / or fuel supply to the combustion chambers 19 is adjustable. At the engine control unit 21 is a facility 23 connected to detect a speed signal for the internal combustion engine, which may, for example, an inductive speed sensor aufwes. At the engine control unit 21 can be connected in a conventional manner other sensors that are not shown in detail in the drawing.

The electric motor 13 is via an electrical drive device 21 connected to a battery. With the help of the drive device 21 can the electric motor 1 operated both as a drive motor and as a generator for charging the battery and / or food to electrical consumers.

The dual-clutch transmission 14 has a first partial transmission with a first input shaft 25 and a second partial transmission with a second input shaft 26 , The input shafts 25 . 26 are using a switching device 27 each with a gear to the output shaft 15 connectable. As in 1 is recognizable, are a first, third and fifth gear and a reverse gear of the first input shaft 25 and second, fourth and sixth gears of the second input shaft 26 assigned. With the help of the switching device 27 can gears associated with each gear with on the corresponding input shafts 25 . 26 arranged gears are coupled. The first input shaft 25 is via a first clutch 28 and the second input shaft via a second clutch 29 with a drive shaft 30 the combustion engine 12 coupled. The switching device 27 and the couplings 28 . 29 are with the help of electromotive actuators 31 operable via a dual-clutch transmission control unit 32 are controllable.

For the exhaust gas turbocharger 16 A device for determining the boost pressure is provided. The device has for pressure sensorless determination of the boost pressure from the speed signal and the desired signal in the dual-clutch transmission control unit 32 a data store 33 on, are stored in the parameters, each having a speed value and a desired signal value, a value for the stationary boost pressure of the exhaust gas turbocharger 16 assign. The parameters can be stored as a map, which has been previously recorded, for example, with the help of a corresponding test stand. For transmitting the speed signal and the desired signal to the dual-clutch transmission control unit 32 is the engine control unit 21 over a bus 34 with the dual-clutch transmission control unit 32 connected. The latter has a microprocessor 35 in which runs an operating program, which checks using the stored characteristics, the speed signal and the desired signal, if a turbo lag is present.

Upon detection of a turbo lag, the electric motor becomes 13 with the help of the drive device 24 so controlled and the couplings 28 . 29 as well as the switching device 27 are set so that the electric motor 13 a drive torque on the output shaft 15 transmits which the drive torque of the internal combustion engine 12 supported and thereby at least partially compensated for the turbo lag. Depending on the shift strategy, the second partial transmission is in the neutral position or a straight gear is preselected.

If an odd gait 1 . 3 or 5 inserted and the second partial transmission is arranged in neutral position, the second clutch 29 closed to the electric motor 13 with the drive shaft 30 to pair. If a straight gear 2 . 4 or 6 is preselected, is the second clutch 29 opened so that the electric motor 13 over the second input shaft 26 , the preselected gear, the output shaft 15 , the first input shaft 25 and the first clutch 28 with the drive shaft 30 is coupled.

If a straight gear 2 . 4 or 6 is engaged, is the second clutch 29 closed and the additional torque is from the electric motor 13 over the second input shaft 26 , the second clutch 29 and the gear engaged on the output shaft 15 transfer.

If no turbo lag is detected, the electric motor becomes 13 operated as a generator or idling or the electric motor stops.

In 2 is a flowchart of one in the on the microprocessor 35 running routine integrated routine for detecting the turbo lag. This routine will be during operation of the vehicle powertrain 11 cycle through. When the routine is run through for the first time after start-up, it is assumed that a turbo lag is present because the engine must be accelerated from low speed. The information "Turbocharger present" is stored in a dedicated memory space of the data memory 33 stored. In addition, start values, which preferably have the value 0, are entered in memory locations which are provided for the storage of mean value signals.

When the routine is run through again, by reading out the corresponding memory space of the data memory 33 each checked whether in the previous run a turbo lag was present. If the information that a turbo lag is present is stored in the memory location, a branch is made to a first program branch which is located in 2 is shown on the left. This branch checks to see if the engine speed is greater than a specified one in the data store 33 stored speed signal limit. When the engine speed is greater than the speed signal limit, it is determined that there is no turbo lag and the information "no turbo lag present" is in the dedicated memory location of the data memory 33 stored.

If the engine speed is not greater than the speed signal limit, a branch is made to a second program branch. There it is checked whether the current value of the desired signal is greater than a predetermined, in the data memory 33 stored reference signal limit value. When the value of the desired signal is greater than the desired signal threshold, a first average signal is incremented. Otherwise, the first mean value signal is decremented.

In a further step, the first average value signal is compared with a first limit value in the second program branch. If the first mean value signal is greater than the first limit value, the information "turbo lag not present" in the space provided for the data memory 33 stored. If the first average signal is not greater than the first threshold, the information "turbo lag present" in the data memory 33 stored.

If the information that a turbo lag is present is stored in the memory location, a branch is made to a third program branch which is located in 2 is shown on the right. In this branch is first checked whether the internal combustion engine 12 is off. If this is the case, it is determined that a turbo lag is present and this information is stored in the dedicated memory space of the data memory 33 stored.

• a) der aktuelle Wert des Sollsignals kleiner ist als der Sollsignalgrenzwert oder
• b) die Motordrehzahl kleiner ist der Drehzahlsignalgrenzwert oder
• c) der Kraftfahrzeugantriebsstrang abgebremst wird.

When the internal combustion engine is switched on, a branch is made to a fourth program branch. There it is checked whether

• a) the current value of the desired signal is smaller than the desired signal limit or
• b) the engine speed is less than the speed signal limit or
• c) the motor vehicle drive train is braked.

If at least one of the conditions a) to c) is fulfilled, becomes a second average signal incremented. If none of the conditions a) to c) is met, the second average signal is decremented.

In a further step, the second average value signal is compared with a second limit value in the fourth program branch. If the second average signal is greater than the second threshold, the information "no turbo lag is present" in the space provided for the data memory 33 stored. If the second average signal is not greater than the second threshold, it is determined that a turbo lag is present and this information is stored in the data memory 33 stored.

After determining that a turbo lag is present or absent, the routine is run again. If a turbo lag is present, a drive torque is generated by means of the electric motor and to the output shaft 15 transfer.

11

Motor vehicle drive train

12

combustion engine

13

electric motor

14

Double clutch

15

output shaft

16

turbocharger

17

first turbine

18

second turbine

19

combustion chamber

20

Should signal generator

21

Engine control unit

22

actuator

23

Facility for detecting a speed signal

24

driving

25

first input shaft

26

second input shaft

27

switching device

28

first clutch

29

second clutch

30

drive shaft

31

actuator

32

Double clutch transmission controller

33

data memory

34

bus

35

microprocessor

Claims (6)

Motor vehicle drive train ( 11 ), which is an internal combustion engine ( 12 ) and an electric motor ( 13 ) as a drive, wherein the electric motor ( 13 ) via a drive device ( 24 ) is connectable to a battery, wherein the internal combustion engine ( 12 ) and / or the electric motor ( 13 ) via a dual-clutch transmission ( 14 ) with an output shaft ( 15 ) can be brought into drive connection, and wherein the internal combustion engine ( 12 ) for changing its speed and / or its torque with a desired signal generator ( 20 ) connected actuator ( 22 ), characterized in that the internal combustion engine ( 12 ) an exhaust gas turbocharger ( 16 ) and a device for determining its loading pressure and that the means for determining the boost pressure and the setpoint signal generator ( 20 ) for energizing the electric motor ( 13 ) when a turbo lag occurs with the control device ( 24 ) is in control connection. Motor vehicle drive train ( 11 ) according to claim 1, characterized in that the means for determining the boost pressure comprises at least one pressure sensor which downstream of the exhaust gas turbocharger ( 16 ) preferably in an air supply duct for the internal combustion engine ( 12 ) is arranged. Motor vehicle drive train ( 11 ) according to claim 1 or 2, characterized in that the combustion engine ( 12 ) an engine control unit ( 21 ), in which the device for determining the boost pressure is at least partially integrated, that the dual-clutch transmission ( 14 ) with clutch actuators and / or at least one actuator for actuating a switching device ( 27 ) connected dual-clutch transmission control unit ( 32 ), and that the engine control unit ( 21 ) for transmitting a boost pressure signal to the dual-clutch transmission control unit ( 32 ) is connected to this. Motor vehicle drive train ( 11 ) according to one of claims 1 to 3, characterized in that a device for detecting a speed signal for the internal combustion engine ( 12 ) is provided that the desired signal generator ( 29 ) and the means for detecting the speed signal to the means for determining the boost pressure are connected, and that the means for determining the boost pressure for pressure sensorless determination of the boost pressure from the speed signal and a desired signal of the setpoint signal generator a data memory ( 33 ), in which characteristic quantities are stored, each of which has a value for the steady-state boost pressure of the exhaust gas turbocharger ( 16 ) assign. Motor vehicle drive train ( 11 ) according to claim 4, characterized in that the means for determining the boost pressure comprises a first comparison means for comparing the speed signal with a predetermined speed signal limit and / or for comparing the command signal with a predetermined target signal limit that the first comparison means has an output for a first comparison signal connected to an input of a filter means arranged to form a moving average signal from the first comparison signal, that an output of the filter means for comparing the moving average signal with a predetermined limit value is connected to an input of a second comparison means, and that the second Comparison device is so in control connection with the drive means, that the electric motor in response to a output at a second comparator outputable second comparison signal we are driven d. Motor vehicle drive train ( 11 ) according to claim 5, characterized in that the dual-clutch transmission ( 14 ) a first input shaft ( 25 ) and a second input shaft ( 26 ), each having at least one gear with the output shaft ( 15 ) are connectable, that the first input shaft ( 25 ) via a first clutch ( 28 ) and the second input shaft ( 6 ) via a second clutch ( 29 ) with a drive shaft ( 30 ) of the combustion engine ( 12 ) and that the electric motor ( 13 ) in such a way with the second input shaft ( 26 ) is in drive connection that it via the second clutch ( 29 ) with the drive shaft ( 15 ) can be coupled.