WO2019211022A1

WO2019211022A1 - Drive system for a motor vehicle, method for operation

Info

Publication number: WO2019211022A1
Application number: PCT/EP2019/054964
Authority: WO
Inventors: Andreas Posselt; Marko Lorenz; Andreas Gutscher
Original assignee: Robert Bosch Gmbh
Priority date: 2018-05-04
Filing date: 2019-02-28
Publication date: 2019-11-07
Also published as: DE102018206958A1

Abstract

The invention relates to a drive system (1) for a motor vehicle, comprising an internal combustion engine (2), a turbocharger (3), which is connected, on the pressure side, to the internal combustion engine (2) by a fresh air line (8), a tank (10), which provides liquid fuel for the internal combustion engine (2), and a tank-venting means (11), which has an activated carbon filter (12) connected to the tank (10), the activated carbon filter (12) having a fresh air inlet (14) and a gas outlet (15), the gas outlet (15) being connected to an intake tube (6) of the turbocharger (3) by a gas line (18). It is provided that, for the tank venting, an electric-motor compressor (5, 25) is present and is connected, on the pressure side, to the tank-venting means (11) by an additional line (23, 28), and that the turbocharger (3) is connected, on the pressure side, to the internal combustion engine (2) by an actuatable throttle valve (9) in the fresh air line (8) in such a way that a gas mass flow rate increased by the electric-motor compressor (5, 25) for the tank-venting means (11) is compensated by actuation of the throttle valve (9).

Description

description

title

Drive system for a motor vehicle, method of operation

The invention relates to a drive system for a motor vehicle, with a

Internal combustion engine, with an exhaust gas turbocharger, which is connected on the pressure side by a fresh air line to the internal combustion engine with a liquid fuel for the internal combustion engine providing tank, and with a tank vent, having an associated with the tank activated carbon filter, wherein the activated carbon filter has a fresh air inlet and a gas outlet , wherein the gas outlet through a gas line with a suction pipe of the

Exhaust gas turbocharger is connected.

Furthermore, the invention relates to a method for operating such a drive system.

State of the art

Drive systems and methods thereof are known in the art. To increase the performance, it is known an internal combustion engine

Assign exhaust gas turbocharger, the exhaust gas flow through the

Internal combustion engine is driven, compressing and fresh air

Brennkammern the internal combustion engine supplies. For this purpose, the exhaust gas turbocharger has a turbine driven by the exhaust gas flow and a compressor driven by the turbine. In the combustion chambers, the compressed fresh air is burned together with the fuel supplied to the combustion chambers. The fuel is provided by a tank that leads to the

Tank vent is connected to an activated carbon filter. The activated carbon filter absorbs gaseous components of the fuel and stores them. To regenerate the activated carbon filter this is connected by a gas outlet with a suction pipe of the exhaust gas turbocharger, so that the outgassed Fuel / fuel is supplied through the intake manifold and the exhaust gas turbocharger to the internal combustion engine. It is known, the amount of fuel which is supplied to the internal combustion engine through the tank ventilation, in the metering of liquid fuel by means of the combustion chambers

deduct assigned injectors again.

In conventional drive systems that operate without exhaust gas turbocharger, for the regeneration of the activated carbon filter, a sufficiently long phase with Saugrohrunterdruck must be present, and this phase must occur regularly. In drive systems with exhaust gas turbochargers, however, an intake manifold vacuum can not always be guaranteed, which is why such systems generally have a second point of introduction of the gas line into the drive system. However, for a significant regeneration, the drive system must be in the charged state, the exhaust gas turbocharger thus compress fresh air and generate an overpressure. However, due to the current development, it becomes increasingly difficult to sufficiently regenerate the activated carbon filter.

Disclosure of the invention

The drive system according to the invention with the features of claim 1 has the advantage that a regeneration of the activated carbon filter can be performed at any time. For this purpose, it is provided according to the invention that for tank ventilation an electric motor compressor present and pressure side by a

Additional line is connected to the tank ventilation, and that the

Exhaust gas turbocharger on the pressure side is connected by an arranged in the fresh air line and operable throttle with the internal combustion engine such that an increased by the electric motor compressor for tank ventilation gas mass flow is compensated by the operation of the throttle. By providing an electromotive compressor is achieved that at any time an increased gas flow can be achieved, which also leads to the tank ventilation or the regeneration of the activated carbon filter necessary overpressure or negative pressure in the drive system, regardless of one

Torque request to the internal combustion engine. This ensures regeneration of the activated carbon filter at all times. To avoid that due to the gas flow increased for tank ventilation, the air filling in the combustion chambers the internal combustion engine deviates from a desired air filling, the increased gas mass flow is compensated by the operable throttle. Thus, the throttle valve is actuated, for example, to narrow the flow cross-section of the fresh air line when a tank venting or regeneration of the activated carbon filter is effected by an increased gas mass flow. As a result, the operation of the internal combustion engine is not impaired and yet a regeneration of the activated carbon filter is possible.

According to a preferred embodiment of the invention, the

Exhaust gas turbocharger on a turbine and a compressor, as previously mentioned and the compressor is associated with an electric motor to the

to form electromotive compressor. This is the electromotive

Compressor integrated in the exhaust gas turbocharger. This provides a particularly compact embodiment of the drive system. In particular, for this purpose, the rotor of an electric motor is rotatably arranged on a compressor wheel of the compressor and a turbine wheel supporting the turbine shaft of the exhaust gas turbocharger, whereby a particularly space-saving integration is ensured. Alternatively, the electric motor is arranged next to the exhaust gas turbocharger and by a suitable transmission, for example a

Belt drive or the like, coupled to the shaft of the exhaust gas turbocharger to the compressor of the exhaust gas turbocharger when required by electric motor

drive.

According to an alternative embodiment of the invention, the

Drive system in addition to the exhaust gas turbocharger, which has the compressor and the turbine, the electromotive compressor. Thus, the electromotive compressor is present in addition to the exhaust gas turbocharger and the drive system comprises a total of two compressors, of which at least the separate compressor is driven by an electric motor. Thereby detached from the exhaust gas turbocharger an increased gas volume flow or gas mass flow by driving the electric motor compressor can be provided at any time to perform the regeneration of the activated carbon filter.

Preferably, the electromotive compressor is on the pressure side with the

Gas line connected. This ensures that between elevated, through the Gas line guided mass flow increased oppression on the

Activated carbon filter acts, which improves the regeneration.

Furthermore, it is preferably provided that the additional line opens into a Venturi nozzle as a treble line, wherein the Venturi nozzle is connected on the output side to the intake manifold and the gas line to a suction port of the Venturi nozzle. The Venturi nozzle is thus driven by the gas mass flow supplied by the electromotive compressor, which flows axially through the Venturi nozzle. In particular, radially the suction port is formed, through which the gas line also opens into the Venturi nozzle. Due to the Venturi nozzle increased negative pressure in the

Gas line mouth creates a particularly high negative pressure, which acts on the activated carbon filter and thereby drives the regeneration.

Furthermore, it is preferably provided that the additional line leads downstream of a pressure-side merger of exhaust gas turbocharger and additional electromotive compressor to the venturi nozzle. Thus, the gas mass flows are combined from the exhaust gas turbocharger and the compressor and the resultant total pressure of the Venturi nozzle through the additional line, which branches off from the fresh air line downstream of the merger of the pressure side of the exhaust gas turbocharger and the additional electromotive compressor supplied.

Furthermore, it is preferably provided that the gas outlet of the activated carbon filter is additionally connected downstream of the throttle valve with the fresh air line. This provides a further possibility for the regeneration of the activated carbon filter, which can be used at the same time as, or as an alternative to, the previously described point of introduction of the gassed fuel into the drive system.

Furthermore, it is preferably provided that the additional electromotive compressor and / or the exhaust gas turbocharger in each case a check valve is connected downstream. This ensures that the flow direction of the respective gas flow can not be reversed and safe operation of the drive system is ensured. Furthermore, it is preferably provided that the additional electromotive compressor is connected on the pressure side by an additional line, which serves in particular as a purge line, with the fresh air inlet of the activated carbon filter. As a result, the gas mass flow provided by the electromotive compressor is supplied to the fresh air inlet of the activated carbon filter, whereby the activated carbon filter is actively flushed through the gas flow and expelled fuel from the activated carbon filter and fed through the gas line to the drive system. This active flushing of the activated carbon filter reduces the regeneration time.

Preferably, an actuatable valve is arranged in the purge line to perform the purge process as needed.

Preferably, the purge line is upstream of the valve and downstream of the additional electromotive compressor with the fresh air line

in particular connectable by a check valve. It is thereby achieved that the electromotive compressor both for purging the activated carbon filter through the purge line and for generating increased air fillings of the

Internal combustion engine is usable. Depending on the operation or the state of the valve, the gas mass flow is used for rinsing the activated carbon filter or for charging the internal combustion engine.

Preferably, the gas line, which leads from the activated carbon filter to the suction line, discharges directly into the suction line. In this case, therefore, a Venturi nozzle is dispensed with, because the flushing capacity is already sufficient due to the active flushing of the activated carbon filter.

The inventive method with the features of claim 13 is characterized in that the throttle valve in response to the control of the electromotive compressor set in such a way

or is actuated, that is compensated by the electric motor compressor for tank ventilation increased gas mass flow and the

Air fillings of the internal combustion engine, with unchanged request for a drive torque, remains unchanged. This results in the already mentioned advantages. Further advantages and preferred features emerge in particular from the previously described and from the claims. The following is the

Invention will be explained in more detail with reference to the drawing. To show:

FIG. 1 shows a first exemplary embodiment of an advantageous drive system,

Figure 2 shows a second embodiment of the drive system, and

Figure 3 shows a third embodiment of the drive system, each in a simplified representation.

FIG. 1 shows a first exemplary embodiment of an advantageous drive system 1 for a motor vehicle, which is not shown here in greater detail.

The drive system 1 has an internal combustion engine 2, which is designed here as a reciprocating engine and mechanically with drive wheels of

Motor vehicle is coupled. The internal combustion engine 2 is associated with an exhaust gas turbocharger 3. The exhaust gas turbocharger has a turbine 4 and a compressor 5, wherein the turbine 4 is located in the exhaust line of the internal combustion engine 2 and the compressor 5 in a fresh air line. In particular, the turbine 4, a turbine wheel and the compressor 5 a compressor wheel, which on a

common shaft in the housing of the exhaust gas turbocharger 3 are arranged rotationally fixed, so that the turbine wheel driven by the exhaust gas drives the compressor wheel.

The compressor 5 is connected on the inlet side with a suction pipe 6, through which ambient air, in particular with the interposition of an air filter 7 can be sucked in, as indicated by an arrow in Figure 1. On the pressure side, the compressor 5 is connected to a fresh air line 8, which leads to the

Combustion chambers of the internal combustion engine 2 leads. In the fresh air line 8 is also an operable throttle valve 9 is connected between the compressor 5 and the internal combustion engine 2, by means of which the

Throughflow of the fresh air line 8 is adjustable. The

Internal combustion engine 2 is operated by a gas mixture of fresh air and liquid fuel. The fuel is stored and provided in a tank 10. Because the liquid fuel is outgassing over time, it is necessary to bleed the tank regularly. For this purpose, a tank ventilation 11 is provided, which will be explained in more detail below.

The tank vent 11 has an activated carbon filter 12 as an essential feature. This is connected by a line 13 to the tank 10. In this case, the line 13 opens into the tank 10 above an expected

Liquid level, advantageously through the ceiling of the tank 10 in the interior of the tank 10. The outgassed fuel thus passes through the conduit 13 into the activated carbon filter 12. The activated carbon filter 12 further comprises a fresh air inlet 14 and a gas outlet. Through the gas outlet can stored in the activated carbon filter 12 stored fuel and the

Internal combustion engine to be supplied. For this purpose, the gas outlet 15 is connected by a line 16 with the fresh air line 8 downstream of the throttle valve 9. The gas outlet 15 is an actuatable valve 17th

downstream to control the outflow of the gas from the activated carbon filter 12.

Is the drive system 1 in a charged state in which the compressor 5 compressed fresh air into the combustion chambers of

Internal combustion engine 2 drives, arises at the discharge point of the line 16 in the fresh air line 8 a suction, which has an effect on the activated carbon filter 12. If the valve 17 is actuated at this moment in order to connect the activated carbon filter 12 to the fresh air line 8, fresh air is sucked into the activated carbon filter 12 by the fresh air inlet 14, the fuel stored there is released and transported into the internal combustion engine 2 with the fresh air. Thus, a regeneration of the activated carbon filter. In another operating state, in which the negative pressure in the line 16 can not be generated, is a

Regeneration of the activated carbon filter 12 not possible.

The tank vent 11 therefore has a further gas line 18, which branches off from the gas line 16 downstream of the valve 17 and below

Interposition of a Venturi nozzle 19 to the suction pipe 6 of

Drive device leads. The Venturi nozzle has a suction port 20, to which the gas line 18 is connected, and an inlet 21 and an outlet 22, wherein the outlet 22 is connected to the suction pipe 6. From the compressor 5 of the exhaust gas turbocharger 3, an additional line 23, which branches off from the fresh air line 8, leads to the inlet 21 of the Venturi nozzle 19. The pressure gradient generated by the Venturi nozzle 19 produces a suction at the suction inlet 20, whereby a suction is exerted on the activated carbon filter 12 with the valve 17 open. Characterized the activated carbon filter 12 is regenerated by a correspondingly high flow of fresh air through the venturi 19 is performed.

The exhaust gas turbocharger 3 is also assigned an electric motor 24. In the present case, a rotor of the electric motor 24 is arranged directly on the shaft, which connects the turbine 4 to the compressor 5, rotatably and so far integrated into the exhaust gas turbocharger 3. Alternatively, however, the electric motor could also be arranged outside the exhaust-gas turbocharger 3 and be mechanically connected / coupled thereto.

In order to carry out a regeneration of the activated carbon filter 12, the electric motor 24 is now driven in order to generate an increased gas mass flow, which is in particular at least partially supplied to the Venturi nozzle 19. So that at the same time the air fillings in the combustion chambers of the internal combustion engine 2 are not changed or deviate from what is required by the requested torque of air fillings, the throttle valve 9 is actuated to compensate for the increased gas mass flow and the

Keep air fillings constant.

Thus, the present system allows by increasing the

Gas mass flow means of the electric motor driven compressor 5 to regenerate the activated carbon filter 12, without thereby the operation of the

Internal combustion engine 2 is impaired.

Figure 2 shows a second embodiment of the advantageous drive system 1, wherein from the previous embodiment already known features are provided with the same reference numerals and reference is made in this regard to the above description. The following is intended essentially to the

Differences are received. In contrast to the previous embodiment is now provided that the electromotive compressor is not integrated into the exhaust gas turbocharger 3, especially as an additional electric motor compressor 25 is connected in parallel to the exhaust gas turbocharger 3. By a check valve 26, the additional electromotive compressor 25 is connected to the fresh air line 8 on the pressure side. Also, the exhaust gas turbocharger 3 is a check valve 27th

downstream, wherein the gas streams of the exhaust gas turbocharger 3 and the

Compressor 25 downstream of the check valves 26 and 27 are merged. The additional line 23 branches off downstream of the merger of the gas streams from the fresh air line 8.

This embodiment has the advantage that increasing the

Gas mass flow through the electromotive compressor 25 no

Has effect on the exhaust system of the internal combustion engine 2, because the compressor 25 is not coupled to the exhaust gas turbocharger 3. In addition, the total gas flow that can be supplied to the Venturi nozzle is increased overall, so that improved purging / regeneration of the activated carbon filter 12 is provided.

Figure 3 shows a third embodiment of the drive system 1, wherein already known elements are provided with the same reference numerals and insofar reference is made to the above description. In the following, the differences should be dealt with essentially.

In contrast to the embodiment of Figure 2 is now

provided that the additional electromotive compressor 25 on the pressure side connected by a serving as a purge line additional line 28 to the or another fresh air inlet 29 of the activated carbon filter 12. Downstream of the compressor 25, an actuatable valve 30 is disposed in the purge line to affect the flow area thereof. Upstream of the valve 30, the purge line is connected by the check valve 26, as described above, with the fresh air line 8 or connectable at sufficiently high pressure.

If the compressor 25 is now driven, a gas flow is generated which, when the valve 30 is open, in particular as a normally closed valve is formed, is conveyed through the purge line in the activated carbon filter 12 so that it flushed through or flushed and the fuel stored there is conveyed through the gas line 18 directly into the suction pipe 6, in which case preferably dispensed with the Venturi nozzle. In this case, the generation of a negative pressure is not necessary, but is regenerated by the generated purge line overpressure of the activated carbon filter 12, if necessary. The resulting, additionally in the fresh air line 8 reaching gas mass flow is compensated again by pressing the throttle valve 9, so that the internal combustion engine 2 is not affected during operation.

Claims

claims

1. Drive system (1) for a motor vehicle, with an internal combustion engine (2), with an exhaust gas turbocharger (3), the pressure side by a fresh air line (8) with the internal combustion engine (2) is connected to a liquid fuel for the internal combustion engine (2 ) Providing tank (10), and with a

Tank ventilation (11) having an activated carbon filter (12) connected to the tank (10), wherein the activated carbon filter (12) has a fresh air inlet (14) and a gas outlet (15), wherein the gas outlet (15) by a

Gas line (18) with a suction pipe (6) of the exhaust gas turbocharger (3) is connected, characterized in that for tank venting an electromotive compressor (5,25) and the pressure side by an additional line (23,28) with the tank vent (11 ), and that the exhaust gas turbocharger (3) on the pressure side by an in the fresh air line (8) arranged and operable throttle valve (9) with the internal combustion engine (2) is connected such that a through the electric motor compressor (5,25) for tank ventilation (11) increased gas mass flow through the operation of the throttle valve (9) is compensated.

2. Drive system according to claim 1, characterized in that the exhaust gas turbocharger (3) has a turbine (4) and a compressor (5), and that at least the compressor (5) is associated with an electric motor (24) to the electromotive compressor ( 5) to form.

3. Drive system according to one of claims 1 and 2, characterized in that in addition to the exhaust gas turbocharger (4) having a

Compressor (5) and a turbine (4), the electromotive compressor (25) is present.

4. Drive system according to one of the preceding claims, characterized in that the electromotive compressor (25) on the pressure side is also connected to the gas line (18).

5. Drive system according to one of the preceding claims, characterized in that the additional line (23) opens into a Venturi nozzle (19) as a treble line, wherein the Venturi nozzle (19) on the output side with the suction tube (8) and the gas line (18 ) is connected to a suction port of the Venturi nozzle (19).

6. Drive system according to one of the preceding claims, characterized in that the additional line (23) downstream of a pressure-side merger of the exhaust gas turbocharger (3) and additional

electromotive compressor (25) leads to the Venturi nozzle (19).

7. Drive system according to one of the preceding claims, characterized in that the gas outlet (15) of the activated carbon filter (12) is additionally connected downstream of the throttle valve (9) with the fresh air line (8).

8. Drive system according to one of the preceding claims, characterized in that the additional electromotive compressor (25) and / or the exhaust gas turbocharger (3) in each case a check valve (26,27) is connected downstream.

9. Drive system according to one of the preceding claims, characterized in that the additional electromotive compressor (25) on the pressure side through the additional line (28) with the fresh air inlet (14,29) of the activated carbon filter (12) is connected.

10. Drive system according to claim 9, characterized in that in the additional line (28) an actuatable valve (30) is arranged.

11. Drive system according to one of claims 9 and 10, characterized in that the additional line (28) upstream of the valve (30) and downstream of the additional electromotive compressor (25) with the fresh air line (8) by a check valve (26) is connectable.

12. Drive system according to claim 11, characterized in that the gas line (18) opens directly into the suction pipe (6).

13. A method for operating a drive system (1) of a

Motor vehicle comprising an internal combustion engine (2), an exhaust gas turbocharger (3) connected on the pressure side by a fresh air line (8) to the internal combustion engine (2), a tank (10) providing a liquid fuel for the internal combustion engine (2) and a tank vent (11) wherein the tank vent (11) has an activated carbon filter (12) connected to the tank (10), which has a fresh air inlet (14, 29) and a gas outlet (15), wherein the

Gas outlet (15) through a gas line (18) with a suction pipe (6) of the

Exhaust gas turbocharger (3) is connected, characterized in that for tank ventilation (11) a compressor (5,25) driven by an electric motor and the pressure side by an additional line to the tank vent (11) is connected, and that the exhaust gas turbocharger (3) on the pressure side by a in the throttle valve (9) is actuated such that a through the electric motor driven compressor (5,25) for tank ventilation (11) increased gas mass flow through the Throttle valve (9) is compensated.