DE102014220677A1 - Method for operating a charging system of an internal combustion engine and internal combustion engine with a charging system - Google Patents

Abstract

In a method for operating a supercharging system of an internal combustion engine (2), which has an exhaust gas turbocharger (8) and an electrically driven compressor (15) connected to the intake air path (4), the compressor (15) becomes in certain operating states of the supercharging system Generator mode operated.

Description

The invention relates to a method for operating a charging system of an internal combustion engine and to an internal combustion engine with a charging system. The charging system may be an exhaust gas turbocharger system, but also, for example, a turbocompound system, externally charged or charged by the internal combustion engine mechanical supercharger or pressure wave superchargers or combinations thereof.

From the DE 20 2014 103 104 U1 For example, an exhaust gas turbocharger system is known, which has an electrically drivable compressor upstream of the compressor of the exhaust gas turbocharger.

Such a system allows a faster build-up of torque in the low speed range to mitigate the so-called turbo lag by the electrically driven compressor. However, its power consumption is higher due to the power consumption of the compressor than in a conventional exhaust gas turbocharger, which does not include an electrically driven compressor.

It is an object of the present invention to specify a most energy-efficient method for operating a charging system of an internal combustion engine. Furthermore, a particularly efficient internal combustion engine is to be specified with a charging system.

This object is achieved with the subject matter of the independent claims. Advantageous developments emerge from the dependent claims.

According to one embodiment of the invention, a method for operating a supercharging system of an internal combustion engine is provided which comprises an exhaust gas turbocharger and an electrically driven compressor connected in the intake air path, wherein the compressor is operated in a generator mode in certain operating states of the supercharging system.

A generator mode of the compressor is understood to mean an operating mode in which the electric machine of the compressor, which is otherwise operated as an electric motor, is operated as a generator and converts energy from the intake air flow into electrical energy. The generator is driven by the compressor, which extracts kinetic energy from the intake air.

The method has the advantage that in certain operating states of the internal combustion engine otherwise unused energy is converted from the intake air into electrical energy and is available in the vehicle. The electrical energy can be stored in the vehicle and made available to various consumers, in particular also the electric compressor itself. The method is therefore particularly energy-efficient.

The operation of the compressor in the generator mode can be carried out in various operating states of the internal combustion engine described below, in which otherwise unused energy for driving the compressor is available.

In one embodiment, the method includes determining a compressor power to be provided by the compressor and operating the compressor in the generator mode when the compressor power to be provided by the compressor is within a predetermined range of values.

For example, in this embodiment, the compressor may be operated in the generator mode when it is determined that the compressor power to be provided by the compressor is zero or less than zero. In this case, the compressor in the intake air flow is not needed and its electric machine can be used as a generator.

In one embodiment, the compressor is operated in the generator mode when a boost pressure in the exhaust stream exceeds a predetermined value.

In this embodiment, the compressor can be used in generator mode in such cases, in which otherwise a wastegate of the turbocharger would be opened in order to pass excess exhaust gas to the exhaust gas turbine. This has the advantage that the intake air is throttled by applying regenerative torque, which on the one hand electrical energy is generated, and on the other hand, the optimally required at this operating point intake air mass is promoted.

In one embodiment, the compressor is operated during phases of fuel cutoff of the internal combustion engine in the generator mode. In this case, with the clutch of the internal combustion engine, the kinetic energy is used in the vehicle by an air flow is generated by the piston movement, which can drive the compressor in the generator mode.

In one embodiment, electrical energy generated in the generator mode of the compressor is fed into a vehicle electrical system. Under a feed to the electrical system is thereby a storage of electrical energy and / or their immediate Use understood by electrical consumers in the vehicle. The energy is thus available to the various consumers in the vehicle.

In one embodiment, predictive path data and / or environmental data are used to determine those operating states of the supercharging system in which the compressor is operated in the generator mode.

In this embodiment, therefore not only current data of an engine control of the internal combustion engine are included in the determination of the operating conditions, but it will include more data to be able to determine occurring operating conditions in the near future. In particular, these data may be data from an environmental sensor system, for example radar or optical camera, in addition GPS data and / or data of a driver assistance system.

In one embodiment, predictive path data and / or environmental data are used to determine an amount of electrical energy that can be provided in the generator mode of the compressor. In this case, too, these data may be data from an environment sensor system, for example a radar or optical camera, as well as GPS data and / or data from a driver assistance system.

The knowledge of an amount of electrical energy that can be provided by the compressor in the generator mode has the advantage that the consumption of electrical energy on board the vehicle can be optimized. This is particularly advantageous because a larger number of electrical consumers are installed in modern vehicles, some of which have at least a temporary considerable energy consumption.

Another aspect of the invention relates to a computer program product comprising a computer readable medium and program code stored on the computer readable medium which, when executed on a computing unit, directs the computing unit to execute a method according to any one of the embodiments.

The arithmetic unit is designed in particular as an engine control unit.

According to one aspect of the invention, an internal combustion engine is provided with a supercharging system having an exhaust gas turbocharger and an electrically driven compressor connected in the intake air path, wherein the electrically drivable compressor is operable in a generator mode (in particular depending on the operating state of the supercharging system).

The fact that the compressor can be operated in a generator mode presupposes that its electric machine is basically suitable for operation as a generator. Furthermore, a storage facility for the generated electrical energy is provided, which is designed in particular as an electrical energy storage. It is therefore possible to feed the generated electrical energy into the electrical system.

The fact that the compressor can be operated in the generator mode depending on the operating state of the charging system means that devices are provided which enable a determination of the operating state and a control of the electric machine depending on the determined operating state. This may include in particular a sensor for determining the operating state and control devices with appropriate software.

The combustion engine has the advantage that it can be operated with particularly low consumption, because the energy present in the system is used particularly well.

In one embodiment, the electrically drivable compressor is disposed in the intake air path downstream of a compressor of the exhaust gas turbocharger. Alternatively or additionally, the electrically drivable compressor may be arranged in the intake air path upstream of a compressor of the exhaust gas turbocharger. It can also be provided more than one electrically driven compressor.

In one embodiment, the electric machine operates with the turbine on a common shaft and drives the electrically driven compressor, which is identical to the compressor of the exhaust gas turbocharger. In this embodiment, a transmission, such as a planetary gear, be connected between the electric machine and the shaft.

According to one aspect of the invention, a vehicle is specified with the described internal combustion engine.

Embodiments of the invention will now be described with reference to the accompanying figures.

1 shows schematically a vehicle with an internal combustion engine according to a first embodiment of the invention,

2 schematically shows a vehicle with an internal combustion engine according to a second embodiment of the invention and

3 schematically shows a vehicle with an internal combustion engine according to a third embodiment of the invention.

The vehicle 1 , this in 1 only shown by dashed lines, has an internal combustion engine 2 as a drive motor, which is also shown only dashed. The internal combustion engine 2 is designed as a motor control unit arithmetic unit 3 assigned.

The vehicle 1 points one in the direction of the arrow 5 flowed through the intake air path 4 as well as one in the direction of the arrow 7 flowed through the exhaust air path 6 on. The internal combustion engine 2 has an exhaust gas turbocharger 8th on with one in the intake air path 4 switched compressor, in a known manner by a in the exhaust air path 6 switched turbine 10 is driven. The turbocharger 8th includes one in a bypass line 12 switched wastegate 11 , which can be opened at high boost pressure to excess exhaust gas on the turbine 10 to pass by.

At the compressor 9 the exhaust gas turbocharger 8th is also a bypass line 13 with a bypass flap 14 intended.

In the flow direction of the intake air upstream of the exhaust gas turbocharger 8th is another compressor 15 in the intake air path 4 Switched by an electric machine 16 is operated. The electrically operated compressor 15 also has a bypass line 17 with a bypass flap 18 on. Intercoolers are not shown in the merely schematic representation.

The compressor 15 is designed to be operable in the generator mode. That means the compressor 15 kinetic energy from the intake air path 4 record and thus the electric machine 16 can operate as a generator. This is done depending on the operating state of the supercharging system, at least from the exhaust gas turbocharger 8th and the electrically operated compressor 15 consists. To the compressor 15 or the electric machine 16 to be able to control depending on the operating state of the charging system, is a signal line 19 from the arithmetic unit 3 to the electric machine 16 with power electronics and possibly also to the compressor 15 intended.

The arithmetic unit 3 has a processing unit 20 and a computer readable medium 21 on. The processing unit 20 For example, it can be designed as an electronic processor, in particular as a microprocessor or microcontroller. The computer-readable medium 21 can for example be designed as EEPROM, flash memory or flash EEPROM or NVRAM. On the computer readable medium 21 is stored program code, which when on the arithmetic unit 3 is executed, the arithmetic unit 3 to carry out the above-mentioned embodiments of the method.

To determine an operating state of the charging system is the arithmetic unit 3 with exemplary sensors shown 22 . 23 via signal lines 24 . 25 connected. Depending on the determined operating state, the arithmetic unit controls 3 over the signal line 19 the electric machine 16 with power electronics on.

In an embodiment not shown, the electrically operated compressor 15 downstream of the exhaust gas turbocharger 8th in the intake air path 4 connected.

2 schematically shows a vehicle 1 with an internal combustion engine 2 according to a second embodiment of the invention. This is different from the one in 1 shown first embodiment in that the electric machine 16 working on the same shaft as the turbine 10 the exhaust gas turbocharger 8th , The electrically driven compressor 15 is identical to the compressor in this embodiment 9 the exhaust gas turbocharger 8th , Also in this design, it is envisaged that the electric machine 16 is operable as a generator depending on the operating state of the charging system.

3 schematically shows a vehicle 1 with an internal combustion engine 2 according to a third embodiment of the invention. This is different from the one in 1 shown first embodiment also in that the electric machine 16 working on the same shaft as the turbine 10 the exhaust gas turbocharger 8th , However, for the electric machine 16 a gearbox 26 , For example, a planetary gear provided. The bypass line 13 with the bypass flap 14 are in 3 for better clarity, not shown.

The electrically driven compressor 15 is identical to the compressor also in this embodiment 9 the exhaust gas turbocharger 8th , Also in this design, it is envisaged that the electric machine 16 is operable as a generator depending on the operating state of the charging system.

In the following, various operating states of the internal combustion engine will be exemplified 2 represented with the charging system.

In a first operating state of the exhaust gas turbocharger 8th and the electric compressor 15 used in combination during the acceleration phase.

In a second operating state of the exhaust gas turbocharger 8th for charging the internal combustion engine 2 used, the compressor 15 but operated in generator mode. In those operating points where excess exhaust gas through the wastegate 11 at the turbine 10 would be passed, ie at a high boost pressure, the intake air by applying regenerative torque through the compressor 15 throttled.

In a third operating state, the compressor 15 during periods of fuel cut in Generator mode operated. Then all the flaps except the bypass flap 18 open, even a throttle valve, not shown, of the internal combustion engine 2 , In this operating condition is due to the kinetic energy in the vehicle 1 with the clutch of the internal combustion engine closed 2 By "pumping" the piston creates an airflow that drives the compressor 15 drives. The air flow may also be due to a valve overlap of the intake and exhaust valves of the internal combustion engine 2 be generated. The air flow transfers kinetic energy to the compressor, which is the electric machine used as the generator 16 drives.

LIST OF REFERENCE NUMBERS

1

 vehicle

2

internal combustion engine

3

 computer unit

4

 intake air path

5

 Arrow (flow direction)

6

 Exhaust air path

7

 Arrow (flow direction)

8th

 turbocharger

9

 compressor

10

 turbine

11

 wastegate

12

 bypass line

13

 bypass line

14

 bypass damper

15

 compressor

16

 electric machine

17

 bypass line

18

 bypass damper

19

 signal line

20

 processing unit

21

 computer readable medium

22

 sensor

23

 sensor

24

 signal line

25

 signal line

26

 transmission

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 202014103104 U1 [0002]

Claims (13)

Method for operating a charging system of an internal combustion engine ( 2 ), which has an exhaust gas turbocharger ( 8th ) and one in the intake air path ( 4 ), electrically driven compressors ( 15 ), wherein the compressor ( 15 ) is operated in certain operating states of the charging system in a generator mode. The method of claim 1, wherein the method comprises: determining a through the compressor ( 15 ) to be provided compressor power; - operating the compressor ( 15 ) in generator mode when passing through the compressor ( 15 ) is to be provided within a specified range of values. Method according to claim 1 or 2, wherein the compressor ( 15 ) is operated in the generator mode when a boost pressure in the exhaust stream exceeds a predetermined value. Method according to one of claims 1 to 3, wherein the compressor ( 15 ) during phases of the fuel cutoff of the internal combustion engine ( 2 ) is operated in generator mode. Method according to one of claims 1 to 4, wherein in the generator mode of the compressor ( 15 ) electrical energy is fed into a vehicle electrical system. Method according to one of claims 1 to 5, wherein for determining the operating states of the supercharging system, in which the compressor ( 15 ) is operated in generator mode, predictive route data and / or environmental data are used. Method according to one of claims 1 to 6, wherein for determining a generator in the operation of the compressor ( 15 ) amount of electrical energy predictive route data and / or environmental data are used. Computer program product comprising a computer readable medium ( 21 ) and on the computer-readable medium ( 21 stored program code which, when stored on a computer unit ( 3 ) is executed, the arithmetic unit ( 3 ) to carry out a method according to one of claims 1 to 7. Internal combustion engine ( 2 ) with a supercharging system that has an exhaust gas turbocharger ( 8th ) and one in the intake air path ( 4 ), electrically driven compressors ( 15 ), wherein the electrically driven compressor ( 15 ) is operable in a generator mode. Internal combustion engine ( 2 ) according to claim 9, wherein the electrically driven compressor ( 15 ) in the intake air path ( 4 ) downstream of a compressor ( 9 ) of the exhaust gas turbocharger ( 8th ) is arranged. Internal combustion engine ( 2 ) according to claim 9, wherein the electrically driven compressor ( 15 ) in the intake air path ( 4 ) upstream of a compressor ( 9 ) of the exhaust gas turbocharger ( 8th ) is arranged. Internal combustion engine according to claim 9, wherein the electric machine ( 16 ) with the turbine ( 10 ) works on a common shaft and the electrically driven compressor ( 15 ), which is connected to the compressor ( 9 ) of the exhaust gas turbocharger is identical. Vehicle ( 1 ) with an internal combustion engine ( 2 ) according to any one of claims 9 to 12.

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