DE102012201111A1 - Hybrid drive operating method for use in motor vehicle, involves providing turbocharger, performing boost pressure reduction, and providing set of compressors for turbocharger that is partially compensated - Google Patents

Abstract

The method involves providing a turbocharger having a drive source (2) i.e. gas-turbo-loaded diesel engine, and an electric machine that is designed as another drive source (3). The latter drive source is utilized for charging an energy accumulator (4) that cooperates with the latter drive source. A function of a driver-requested torque is provided by the former drive source, and by the latter drive source. A boost pressure reduction is performed, and a set of compressors is provided for the turbocharger that is partially compensated. An independent claim is also included for a control device.

Description

The invention relates to a method for operating a hybrid drive according to the preamble of claim 1. Furthermore, the invention relates to a control device of a hybrid drive according to the preamble of patent claim 9.

In order to reduce fuel consumption and exhaust emissions, hybrid vehicles are increasingly being used in motor vehicles. A hybrid drive comprises a first drive source, which is designed as an internal combustion engine or internal combustion engine, and a second drive source, which is preferably designed as an electric machine. The second drive source cooperates with an energy store, which is charged more in the regenerative operation of the second drive source and which is more strongly discharged in the motor operation of the second drive source. This energy store may be, for example, an electrical energy store, a mechanical energy store such as a flywheel mass storage or a hydraulic energy store.

The present invention relates to a method for operating a hybrid drive and a control device of such a hybrid drive, in which the first drive source is designed as a supercharged internal combustion engine, for example as exhaust-gas-charged diesel engine or exhaust-gasoline engine. With the present invention, in such a hybrid drive in a spontaneous or transient torque demand by a driver, a reduced fuel consumption and reduced emissions operation of the hybrid drive should be ensured.

From the EP 1 577 138 A2 a method for operating a hybrid drive is known, wherein in a transition from a first operating state with a first drive torque to a second operating state with a lower second drive torque before switching to the second operating state, a drive torque of the internal combustion engine via a reduction of cylinder filling and / or a closing of a throttle valve is reduced, and wherein in addition the drive torque is reduced by a counter to the drive unit opposing counter-torque of at least one electric machine.

Proceeding from this, the object of the present invention is to provide a novel method for operating a hybrid drive and a novel control device of a hybrid drive.

This object is achieved by a method according to claim 1.

According to the invention, a torque request to the first drive source is delayed and / or reduced to ensure a reduced fuel consumption and reduced emissions operation of the hybrid drive with an increase in the driver's desired torque, wherein a dynamic reduction caused thereby by an instantaneous request to the second drive source is at least partially compensated, and further a thereby caused boost pressure reduction is at least partially compensated by electrically driving at least one compressor of the or each turbocharger.

With the present invention, it is proposed not only to delay and / or reduce the torque request to the first drive source with an increase in the driver's desired torque, but also to at least partially compensate for the dynamic reduction caused thereby by a torque request to the second drive source and, secondly to at least partially compensate for a boost pressure reduction caused thereby by electrically driving the or each compressor of the or each turbocharger.

This makes it possible, despite a delayed and / or reduced torque request to the exhaust gas-charged first drive source or internal combustion engine on the one hand to provide a desired torque on the output and on the other hand to avoid dropping the boost pressure. Due to the fact that the boost pressure is kept high by the electric driving of the or each compressor of the or each turbocharger in spite of the delayed and / or reduced torque request to the first drive source or internal combustion engine, lean combustion in the first drive source or internal combustion engine can be realized whereby a particularly advantageous, reduced-emission operation of the first drive source or the internal combustion engine and thus of the hybrid drive can be ensured.

Preferably, the or each compressor is electrically driven such that the charge pressure for the internal combustion engine generated thereby corresponds to the boost pressure that would be formed on increasing the driver's desired torque without delay and / or reduction of the torque request to the first drive source, or that the boost pressure generated thereby for the internal combustion engine is greater than the boost pressure that would form when increasing the driver's desired torque without delay and / or reducing the torque request to the first drive source. Then, when the electric driving of the or each Compressor of the or each turbocharger takes place such that the boost pressure generated thereby at least corresponds to that boost pressure, which would be formed on increasing the driver's desired torque without delay and / or reduction of the instantaneous demand on the first drive source, a particularly advantageous combustion air-fuel ratio in the Internal combustion engine can be provided. As a result, particularly low particulate emissions and thus exhaust emissions of the internal combustion engine and thus of the hybrid drive can be ensured.

According to an advantageous embodiment of the invention, depending on the boost pressure, an amount of fuel to be supplied to the engine is determined such that a combustion air-fuel ratio is greater than a threshold and the first drive source provides the delayed and / or reduced torque request to the first drive source. Hereby, a particularly advantageous operation of the hybrid drive is possible, namely on the one hand while ensuring a reduced-emission and reduced consumption operation of the hybrid drive and on the other hand, while ensuring the desired torque by the driver with low exhaust emissions.

According to a further advantageous development of the invention, the instantaneous demand on the first drive source is delayed and / or reduced as a function of a state of charge of the energy store. The delay and / or reduction of the instantaneous request to the first drive source as a function of a state of charge of the energy store is particularly preferred, since in this way it can be easily and reliably taken into account to what extent a reduction in dynamics caused by the delay and / or reduction of the instantaneous request to the first drive source can be compensated by the second drive source.

The control device according to the invention is defined in claim 9.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

1 a diagram of a hybrid drive with a control device according to the invention;

2 a schematic of an internal combustion engine of the hybrid drive of 1 ;

3 a schematic of an alternative internal combustion engine of the hybrid drive of 1 ;

4 a diagram to illustrate the method according to the invention or the operation of the control device according to the invention.

1 shows a highly schematic hybrid drive 1 acting as the first drive source 2 a exhaust-gas-charged internal combustion engine and as a second drive source 3 an electric machine comprises.

With the second drive source 3 acts an energy storage 4 together, which is preferably an electrical energy storage. At the energy storage 4 It may also be a mechanical energy storage such as a flywheel energy storage or a hydraulic energy storage.

The hybrid drive 1 is a control device 5 assigned to control or regulate the operation of the hybrid drive, wherein the control means 5 with the first drive source 2 , the second drive source 3 and the energy storage 4 via a data interface 6 according to the dot-dashed arrows 7 . 8th and 9 Exchanges data.

So the controller exchanges 5 with the first drive source designed as a supercharged internal combustion engine 2 according to the arrow 7 Data from.

Further, the controller exchanges 5 with the second drive source, preferably designed as an electrical machine 3 according to the arrow 8th and with the energy storage 4 according to the arrow 9 Data from.

Further shows 1 an accelerator pedal 10 with which a driver can specify a driver's desired torque by pressing the accelerator pedal, wherein a driver-side operation of the accelerator pedal 10 according to the arrow 11 the control device 5 also via the interface 6 provided.

During operation of the hybrid drive, a driver's desired torque, which a driver actuates by means of the accelerator pedal 10 pretends, on the one hand from the first drive source 2 , So from the supercharged internal combustion engine, and on the other hand from the second drive source 3 , in particular the electric machine, are provided at an output. Then, if the second drive source 3 is operated by a motor, the same at the output drive torque under heavy discharge of the energy storage 4 ready. Then, on the other hand, if the second drive source 3 is operated as a generator, it serves the more powerful charging of the energy storage 4 , in which case the drive source 3 provides no drive torque at the output.

2 shows details of a first variant of a supercharged internal combustion engine or a supercharged internal combustion engine, wherein in 2 the actual internal combustion engine 12 a turbocharger 13 is assigned to a turbine 14 and a compressor 15 includes. Exhaust gas, which is the internal combustion engine 12 leaves is in the turbine 14 of the turbocharger 13 relaxed, thereby recovering energy for driving the compressor 15 of the turbocharger 13 is used. The turbine 14 of the turbocharger 13 leaving exhaust gas is an exhaust aftertreatment 16 fed. In the compressor 15 compressed combustion air or charge air is upstream of the internal combustion engine 12 via a charge air cooler 17 guided. Further shows 2 an exhaust gas recirculation 18 that is an exhaust gas recirculation valve 19 and an exhaust gas recirculation cooler 20 includes to the downstream of the intercooler 17 cooled charge air with recirculated exhaust gas upstream of the internal combustion engine 12 to mix. Further shows 2 a wastegate valve 21 , with which exhaust, which does not have the turbine 14 of the turbocharger 13 to be guided, at the turbine 14 passing directly towards exhaust aftertreatment 16 can be directed.

3 shows a variant of the first drive source 2 , in which the actual internal combustion engine 12 two turbochargers 13 . 13 ' are assigned, so as to ensure a two-stage charge of the charge air. So has each of the two turbochargers 13 . 13 ' each with a turbine 14 . 14 ' , a compressor 15 . 15 ' and a wastegate valve 21 , respectively 21 ' , The compressor 15 ' of the turbocharger 13 ' is also a bypass valve 23 assigned.

In operation, the hybrid drive depends on the driver-side operation of the accelerator pedal 10 a driver request torque requested, which is the hybrid drive 1 on the one hand via the first drive source 2 or the supercharged internal combustion engine and on the other hand via the second drive source 3 or the electric machine can provide at an output.

To a reduced fuel consumption and reduced emissions operation of the hybrid drive 1 to ensure an increase in the driver's desired torque, according to the invention is dependent on the increase of the driver's desired torque torque request to the first drive source 2 , So to the supercharged internal combustion engine, delayed and / or reduced, thereby causing a reduction in dynamics by a torque request to the second drive source 3 , So in the embodiment shown to the electric machine, at least partially compensated.

this shows 4 highly schematic, with in 4 over time t a moment M is plotted. If there is a sudden or step-like increase of the driver command torque M-FW at time t1, but a torque request M-VM to the first drive source 2 or the internal combustion engine according to 4 is delayed and / or reduced relative to the driver request torque M-FW, this delay and / or reduction of the torque request M-VM to the first drive source 2 by a moment request M-EM to the second drive source 3 or to the electric machine preferably completely, but at least partially compensated to provide a drive torque corresponding to the desired driver's desired torque. As a result, by the reduction and / or delay of the torque request M-VM to the first drive source 2 caused dynamic reduction are at least partially compensated.

In addition to these measures, the invention also proposes a method by delaying and / or reducing the instantaneous demand M-VM to the first drive source 2 or the internal combustion engine caused boost pressure reduction by electrically driving the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' at least partially compensate, wherein the respective compressor 15 respectively. 15 ' of the respective turbocharger 13 respectively. 13 ' this is an electric motor 22 respectively. 22 ' assigned. So shows 2 that the compressor 15 of the turbocharger 13 an electric motor 22 assigned. In the variant of 3 , in which a multi-stage turbocharger is guaranteed, each of the compressors 15 . 15 ' the turbocharger 13 . 13 ' a separate electric motor 22 . 22 ' assigned.

According to the invention, when the driver's desired torque M-FW is increased, on the one hand a torque request M-VM is transmitted to the first drive source 2 or the supercharged internal combustion engine 12 delayed and / or reduced, on the other hand, thereby causing a reduction in dynamics by a torque request M-EM to the second drive source 3 or the electric machine at least partially, preferably completely, compensated. In addition, thereby causing boost pressure reduction by an electric driving or electrical boosting of the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' at least partially, preferably completely, compensated.

By phlegmatizing the instantaneous request M-VM to the supercharged internal combustion engine 12 becomes the fuel consumption of the internal combustion engine 12 reduced, as well as the exhaust emissions of the same.

By the at least partial compensation of the thereby caused boost pressure reduction can in the internal combustion engine 12 a particularly advantageous combustion air-fuel ratio in the sense of lean combustion of the fuel in the internal combustion engine 12 be provided, which exhaust emissions can be further reduced.

The invention thus enables a particularly low-emission and low-consumption operation of a hybrid drive 1 at an increase in a driver's desired torque.

According to a first advantageous embodiment of the invention, the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' the supercharged internal combustion engine at a phlegmatization, namely delay and / or reduction, in the instantaneous demand M-VM to the supercharged internal combustion engine 12 electrically driven such that the thus generated boost pressure for the internal combustion engine 12 corresponds to that boost pressure, the increase in the driver's desired torque M-FW without the phlegmatization, ie without the delay and / or reduction, the instantaneous request to the supercharged internal combustion engine 12 would train. This can be an advantageous, low-emission operation of the hybrid drive 1 be guaranteed.

According to a second advantageous embodiment of the invention, the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' the supercharged internal combustion engine so electrically driven that the boost pressure generated by the electric boosting for the internal combustion engine 12 is greater than the boost pressure, which without the phlegmatization, ie without the delay and / or reduction, the instantaneous request to the internal combustion engine 12 training would increase if the driver's request torque. As a result, the proportion of combustion air relative to the fuel can be further increased in order to achieve even leaner combustion in the internal combustion engine 12 ensuring that exhaust emissions can be further reduced.

Depending on the boost pressure resulting from electrical powering or electrical boosting of the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' the charged internal combustion engine is that of the internal combustion engine 12 determined fuel quantity, namely such that a combustion air-fuel ratio is greater than a threshold value and that the first drive source 2 , that is, the internal combustion engine, the delayed and / or reduced torque request can provide to the same.

The reduction and / or delay of the instantaneous request to the supercharged internal combustion engine 12 with an increase in the driver's desired torque is preferably carried out depending on the state of charge of the energy storage 4 ,

In the in 4 the variant shown, the torque request M-VM to the first drive source 2 So to the supercharged internal combustion engine 12 Delayed and / or reduced in such a way that in the shown, step-like or sudden increase of the driver's desired torque M-FW the instantaneous demand M-VM of the internal combustion engine is initially increased suddenly or with a maximum, temporal gradient maximum on the maximum Saugmotorisch without charging available torque MS , And that then the torque demand M-VM is increased to the engine to the driver's desired torque M-FM continuously relatively slowly, in particular, as in 2 shown, linear. Such a phlegmatization of the instantaneous request to the internal combustion engine 12 or the first drive source of the hybrid drive 1 preferably takes place when the state of charge of the energy store 4 is relatively low.

Then, if the state of charge of the energy store 4 is relatively high, the phlegmatization of the torque request M-VM to the internal combustion engine 12 or the first drive source of the hybrid drive 1 done differently, namely such that in a stair-like or sudden increase of the driver's desired torque M-FW the torque request M-VM to the internal combustion engine 12 or the first drive source of the hybrid drive 1 is increased according to a first variant to the driver's desired torque relatively quickly continuously, preferably linearly, or that according to a second variant, the instantaneous demand M-VM is initially increased suddenly or with maximum temporal gradient maximum on the maximum suction motor without charging torque, then the Momentum request is kept approximately constant, and that subsequently the torque request M-VM to the internal combustion engine 12 to the driver's desired torque is increased relatively quickly continuously, preferably linearly.

Although the variants described above in the phlegmatization of the instantaneous request to the internal combustion engine 12 or the first drive source of the hybrid drive 1 depending on the state of charge of the energy storage 4 are preferred, are also other Phlegmatisierungen, so delays and / or reductions, the instantaneous demand M-VM to the internal combustion engine 12 possible.

For the invention is important that this phlegmatization of the instantaneous demand M-VM, or the effects of this phlegmatization, in two different ways is at least partially compensated or be, namely by a corresponding instantaneous request to the second drive source 3 or electrical machine and by an electrical driving or electrical boosting of the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' ,

The corresponding instantaneous request to the second drive source 3 or electrical machine is used to at least partially compensate for a reduction in dynamics, whereas the electrical driving or electrical boosting of the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' the partial compensation of a boost pressure reduction is used.

The present invention does not relate to the method described above for operating a hybrid drive 1 Rather, the invention also relates to a control device 5 a hybrid drive 1 to carry out the method according to the invention. As already related to 1 described, exchanges the control device for this purpose 5 directly or directly via interposition of a further control device with the first drive source 2 , the second drive source 3 , the energy storage 4 and the accelerator pedal 10 Data from, namely via the interfaces 6 , The control device 5 influenced in the manner described above in an increase of the driver's desired torque M-FW on the accelerator pedal 10 to ensure a reduced fuel consumption and reduced emissions of the hybrid drive 1 the torque request M-VM to the first drive source 2 , So to the supercharged internal combustion engine, and compensates for the resulting reduction in dynamics by a torque request to the second drive source 3 , That is, to the electric machine, and further compensates for a reduction in the boost pressure caused thereby by electrically driving or electrically boosting the or each compressor 15 respectively. 15 ' of the or each turbocharger 13 respectively. 13 ' the first drive source 2 ,

In the control device according to the invention 5 it can be a hybrid control unit or an engine control unit.

Thus, it is possible that a hybrid control unit assumes all the functionalities of the method according to the invention, ie when the driver's desired torque M-FW changes from the driver-side torque request M-FW, the torque request M-VM to the first drive source 2 or the internal combustion engine, the torque request M-EM to the second drive source 3 or the electric machine and a corresponding requirement for the or each electric motor 22 . 22 ' to power the or each compressor 15 . 15 ' of the or each turbocharger 13 . 13 ' generated. In this case, the hybrid control unit then outputs to an engine control unit the driver's desired torque M-FW, the torque input M-VM for the internal combustion engine 12 and drive signals for the or each electric motor 22 . 22 ' so that the engine control unit controls and / or regulates the operation of the internal combustion engine based on these specifications.

Optionally, the hybrid control unit in addition to the driver's desired torque M-FW and the moment preset M-VM to the internal combustion engine 12 still output a preview time, which indicates how behaves within the preview time, the driver's desired torque M-FW. This preview time 5 Can be used to operate the internal combustion engine 12 to control and / or to regulate.

Furthermore, it is possible that partial functionalities of the method according to the invention are not taken over by the hybrid control unit but by the engine control unit. It is thus possible, for example, for the hybrid control unit, when the driver's desired torque M-FW changes, to use only the torque input M-VM for the first drive source 2 or the internal combustion engine and the torque request M-EM for the second drive source 3 or generates and outputs the electric machine, whereas the engine control unit drive signals for the electric motors 22 . 22 ' for electrically driving the or each compressor 15 . 15 ' of the or each turbocharger 13 . 13 ' generated. Further, it is possible that the engine control unit based on a provided by the hybrid controller preview time or another control device preview time, the driver request torque M-FW independently generated independently of the hybrid control unit to operate in combination with the phlegmasierten torque preset M-VM by the hybrid control unit operation first drive source 2 or the internal combustion engine 12 to control and / or to regulate.

The invention can be used in particular in hybrid drives 1 are used, in which the first drive source 2 is designed as a supercharged diesel engine or supercharged Otto internal combustion engine. In any case, it must be at the first drive source 2 to act a exhaust-gas-charged internal combustion engine.

LIST OF REFERENCE NUMBERS

1

hybrid drive

2

first drive source

3

second drive source

4

energy storage

5

control device

6

interface

7

dates

8th

dates

9

dates

10

accelerator

11

dates

12

Internal combustion engine

13

turbocharger

13 '

turbocharger

14

turbine

14 '

turbine

15

compressor

15 '

compressor

16

exhaust aftertreatment

17

Intercooler

18

Exhaust gas recirculation

19

Exhaust gas recirculation valve

20

Exhaust gas recirculation cooler

21

Wastegate valve

21 '

Wastegate valve

22

electric motor

22 '

electric motor

23

bypass valve

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

• EP 1577138 A2 [0004]

Claims (10)

Method for operating a hybrid drive ( 1 ) with a turbocharger designed as a supercharged internal combustion engine ( 13 . 13 ' ) having the first drive source ( 2 ) and with a second drive source designed in particular as an electric machine ( 3 ), the second drive source ( 3 ) for boosting at least one energy storage device interacting with the same ( 4 ) regenerative and for boosting discharge of the or each energy storage device ( 4 ) is operated by a motor, wherein, depending on a driver's desired torque, on the one hand from the first drive source ( 2 ) and on the other hand from the second drive source ( 3 ) in the engine operation of the same a drive torque is requested, characterized in that to ensure a fuel consumption and reduced emissions operation of the hybrid drive ( 1 ) with an increase in the driver's desired torque, a torque request to the first drive source ( 2 ) is delayed and / or reduced, wherein a dynamic reduction caused thereby by a moment request to the second drive source ( 3 ) is compensated for at least partially, and further wherein a thereby caused boost pressure reduction by electrically driving at least one compressor ( 15 . 15 ' ) of the or each turbocharger ( 13 . 13 ' ) is at least partially compensated. Method according to claim 1, characterized in that the or each compressor ( 15 . 15 ' ) is electrically driven such that the charge pressure generated thereby for the first drive source ( 2 ) corresponds to the boost pressure which, when the driver's desired torque is increased without delay and / or reduction of the instantaneous request to the first drive source ( 2 ) would train. Method according to claim 1, characterized in that the or each compressor ( 15 . 15 ' ) is electrically driven such that the charge pressure generated thereby for the first drive source ( 2 ) is greater than the boost pressure which, when the driver request torque is increased without delay and / or reduction of the instantaneous request to the first drive source ( 2 ) would train. Method according to one of claims 1 to 3, characterized in that depending on the boost pressure, one of the first drive source ( 2 ) amount of fuel to be supplied is determined in such a way. A method according to claim 4, characterized in that the fuel quantity is determined such that a combustion air-fuel ratio is greater than a limit value and the first drive source ( 2 ) the delayed and / or reduced torque request to the first drive source ( 2 ). Method according to one of claims 1 to 5, characterized in that the instantaneous request to the first drive source ( 2 ) depending on a state of charge of the energy store ( 4 ) is delayed and / or reduced. A method according to claim 6, characterized in that when the state of charge of the energy store ( 4 ) is relatively high, the instantaneous request to the first drive source ( 2 ) is delayed and / or reduced in such a way that, in the event of a step-like or abrupt increase in the driver's desired torque, the instantaneous request to the first drive source ( 2 ) is increased relatively quickly according to a first variant to the driver's desired torque continuously or after a second variant is increased suddenly or with a maximum temporal gradient maximum on the maximum suction motor without charging torque, then that the torque demand is kept approximately constant, and that subsequently the instantaneous request to the first drive source ( 2 ) is increased relatively quickly to the driver's desired torque relatively quickly. A method according to claim 6 or 7, characterized in that when the state of charge of the energy store ( 4 ) is relatively low, the instantaneous request to the first drive source ( 2 ) is delayed and / or reduced in such a way that, in the event of a step-like or abrupt increase in the driver's desired torque, the instantaneous request to the first drive source ( 2 ) is increased at first suddenly or with a maximum temporal gradient to a maximum of the maximum intake engine torque without charging available torque, and then that the instantaneous request to the first drive source ( 2 ) is increased relatively slowly to the driver's desired torque relatively slowly. Control device ( 5 ) of a hybrid drive ( 1 ), directly or indirectly with the interposition of a further control device with a hybrid drive ( 1 ), which is designed as a supercharged internal combustion engine first drive source ( 2 ) and in particular designed as an electric machine second drive source ( 3 ), one with the second drive source ( 2 ) interacting energy storage ( 4 ) and with an accelerator pedal ( 10 ) Exchanges data, characterized in that the control device ( 5 ) with an increase in the driver's desired torque on the accelerator pedal ( 10 ) to ensure fuel-efficient and emission-reduced operation of the hybrid drive ( 1 ) a moment request to the first drive source ( 2 ) retarded and / or reduced, thereby reducing reduced Dynamic reduction due to an instantaneous request to the second drive source ( 3 ) at least partially compensated and further a thereby caused boost pressure reduction by electrically driving at least one compressor ( 15 . 15 ' ) at least one turbocharger ( 13 . 13 ' ) of the first drive source ( 2 ) at least partially compensated. Control device according to Claim 9, characterized in that it controls and / or regulates the execution of the method according to one of Claims 1 to 8.

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