Drive system with expander shut off upon detection of a leak

Abstract

A drive system may include an internal combustion engine and an expander operated via a working medium. A force transmission device may be disposed between a crankcase and the expander. A first seal may be disposed between the expander and the force transmission device and/or a second seal may be disposed between the force transmission device and the crankcase. A crankcase ventilation line may lead from the crankcase into an intake pipe of the internal combustion engine. An air mass sensor may be disposed in the intake pipe. An engine control unit may be in communication with the air mass sensor, the expander, and the internal combustion engine and may be configured to detect a power of the internal combustion engine and an air mass flow of the air mass sensor and may switch off the expander if a power suddenly rises with the air mass flow remaining constant.

Claims

1. A drive system comprising: an internal combustion engine and an expander operated via a combustible working medium; a power transmission coupling disposed between a crankcase of the internal combustion engine and the expander; at least one of a first seal disposed between the expander and the power transmission coupling and a second seal disposed between the power transmission coupling and the crankcase; a crankcase ventilation line leading from the crankcase into an intake pipe of the internal combustion engine; an air mass sensor disposed in the intake pipe upstream of a junction of the crankcase ventilation line; an engine control unit communicatingly connected to the air mass sensor, the expander and the internal combustion engine; and the engine control unit configured to detect a power of the internal combustion engine and an air mass flow of the air mass sensor and to shut off the expander if the power detected suddenly rises with the air mass flow remaining constant to reduce a leakage of the combustible working medium from the expander into the internal combustion engine.

2. The drive system according to claim 1, wherein the expander is configured as one of an axial piston machine, a scroll and a turbine.

3. The drive system according to claim 1, wherein the combustible working medium comprises ethanol, cyclopentane or acetone.

4. The drive system according to claim 1, wherein the power transmission coupling includes a housing sealed relative to the crankcase of the internal combustion engine and the expander.

5. The drive system according to claim 1, wherein one of: the first seal is exclusively provided and the power transmission coupling is lubricated via oil from the crankcase; the second seal is exclusively provided and the power transmission coupling is lubricated via the combustible working medium of the expander; and the first seal and the second seal are provided.

6. The drive system according to claim 1, wherein the first seal and the second seal are provided; the internal combustion engine includes an exhaust system having an exhaust gas aftertreatment device comprising a filter or a catalytic converter; and a drain pipe structured and arranged to drain the combustible working medium from the power transmission coupling into the exhaust gas aftertreatment device, the drain pipe having an inlet side connected to the power transmission coupling and an outlet side connected to the exhaust gas aftertreatment device.

7. The drive system according to claim 1, wherein the first seal is provided; and the power transmission coupling includes a housing connected to the intake pipe via a connection pipe downstream of the air mass sensor.

8. The drive system according to claim 1, wherein the first seal is provided; a working medium sensor is disposed in the power transmission coupling; and the engine control unit is configured to shut off the expander if the working medium sensor detects the combustible working medium in the power transmission coupling.

9. The drive system according to claim 1, wherein the power transmission coupling is a gearwheel, a transmission, a belt drive, or a chain drive.

10. The drive system according to claim 1, wherein the at least one of the first seal and the second seal is a shaft seal.

11. The drive system according to claim 1, wherein the combustible working medium comprises ethanol.

12. The drive system according to claim 1, wherein the combustible working medium comprises cyclopentane.

13. The drive system according to claim 1, wherein the combustible working medium comprises acetone.

14. The drive system according to claim 1, wherein the first seal is exclusively provided and the power transmission coupling is lubricated via oil from the crankcase.

15. The drive system according to claim 1, wherein the second seal is exclusively provided and the power transmission coupling is lubricated via the combustible working medium of the expander.

16. The drive system according to claim 1, wherein the first seal and the second seal are provided.

17. An operating method of a drive system comprising: providing an internal combustion engine and an expander operated via a combustible working medium; a power transmission coupling disposed between a crankcase of the internal combustion engine and the expander; at least one of a first seal disposed between the expander and the power transmission coupling and a second seal disposed between the power transmission coupling and the crankcase; a crankcase ventilation line leading from the crankcase into an intake pipe of the internal combustion engine; an air mass sensor disposed in the intake pipe upstream of a junction of the crankcase ventilation line; an engine control unit operatively connected to the air mass sensor, the expander and the internal combustion engine; and monitoring a power of the internal combustion engine and an air mass flow from the air mass sensor via the engine control unit, and shutting off the expander in response to detecting a sudden power rise in the internal combustion engine while the air mass flow remains constant to reduce a passing of the combustible working medium from the expander into the internal combustion engine.

18. The operating method according to claim 17, wherein the engine control unit shuts off the expander in response to detecting via a working medium sensor the combustible working medium in the power transmission coupling.

19. A drive system comprising: an internal combustion engine; an expander operated via a combustible working medium; a power transmission coupling disposed between a crankcase of the internal combustion engine and the expander; a working medium sensor disposed in the power transmission coupling; a first seal disposed between the expander and the power transmission coupling and a second seal disposed between the power transmission coupling and the crankcase; a crankcase ventilation line leading from the crankcase into an intake pipe of the internal combustion engine; an air mass sensor disposed in the intake pipe upstream of a junction of the crankcase ventilation line; an engine control unit operatively connected to the air mass sensor, the expander, and the internal combustion engine; the engine control unit configured to detect a power of the internal combustion engine and an air mass flow from the air mass sensor and shut off the expander when the power of the internal combustion engine detected suddenly rises and the air mass flow remains constant to reduce a passing of the combustible working medium from the expander into the internal combustion engine.

20. The drive system of claim 19, wherein the engine control unit is further configured to shut off the expander when the working medium sensor detects the combustible working medium in the power transmission coupling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) There it shows, in each case schematically,

(2) FIG. 1 a drive system according to the invention with a second seal;

(3) FIG. 2 an alternative embodiment of the drive system according to the invention with exclusively one first seal;

(4) FIG. 3 a further alternative embodiment with a first and a second seal;

(5) FIG. 4 a representation as in FIG. 3, however additionally with a drain pipe;

(6) FIG. 5 a representation as in FIG. 3, however additionally with a connection pipe from the fourth transmission device to the intake pipe;

(7) FIG. 6 an embodiment which is not covered by the invention with separately arranged expander.

DETAILED DESCRIPTION

(8) According to FIGS. 1 to 5, a drive system 1 according to the invention comprises an internal combustion engine 2 and an expander 3 that is operated with a combustible working medium. The reference characters for FIGS. 1 to 5 in this case equally apply also to FIG. 6. Between a crankcase 4 of the internal combustion engine 2 and the expander 3, a power transmission device 5 is arranged in the embodiments of FIGS. 1 to 5, wherein between the expander 3 and the power transmission device 5 a first seal 6, in particular a first shaft seal 6, is arranged (see FIGS. 2 to 5). Additionally or alternatively, a second seal 7 can be arranged between the power transmission device 5 and the crankcase 4 of the internal combustion engine 2 (see FIGS. 1 and 3 to 5). Likewise provided is a crankcase ventilation line 8 which leads from the crankcase 4 of the internal combustion engine 2 into an intake pipe 9 of the internal combustion engine 2. In this intake pipe 9, an air mass sensor 10 is arranged upstream of the junction of the crankcase ventilation line 8. In addition to this, an engine control unit 11 which is connected to the air mass sensor 10, the expander 3 and the internal combustion engine 2 is provided. Provided the first seal 6 and/or the second seal 7 are okay, the internal combustion engine 2 is separated hermetically sealed from the expander 3. According to the invention, this engine control unit 11 (ECU) is now designed in such a manner that it detects a power of the internal combustion engine 2 and an air mass flow in the intake pipe 9 and shuts off the expander 3, which can be designed for example as an axial piston machine or as a turbine, provided the detected power of the internal combustion engine 2 rises suddenly with the air mass flow in the intake pipe 9 remaining the same and because of this a passing of working medium from the expander 3 via the intake pipe 9 into the internal combustion engine 2 can be concluded. A sudden increase of the power of the internal combustion engine 2 with otherwise same parameters, i.e. for example with same air mass flow in the intake pipe 9, can exclusively occur in particular provided that additional combustible material, i.e. for example combustible working medium is fed to the internal combustion engine. A sudden increase of the power of the internal combustion engine 2 thus unambiguously points to a leakage of the first seal 6 and/or of the second seal 7 in the embodiments of FIGS. 1 to 5.

(9) The working medium can for example comprise ethanol, cyclopentane or acetone, wherein in particular ethanol is considered more volatile and uncritical in terms of environmental aspects.

(10) Looking at the individual embodiments of the drive system 1 according to the invention it can now be seen that in the case of the drive system 1 according to FIG. 1 merely a second seal 7 is arranged between the internal combustion engine 2, or between its crankcase 4 and the power transmission device 5. In this case, the power transmission device 5 is lubricated via the working medium of the expander 3. In an alternative embodiment, as is shown for example according to FIG. 2, exclusively a first seal 6 is provided between the expander 3 and the power transmission device 5, wherein in this case the power transmission device 5 is also lubricated via the lubricant, for example the oil, from the crankcase 4 of the internal combustion engine 2. Again alternatively to this, the drive system 1 can comprise both the first seal 6 and also the second seal 7 and the power transmission device 5 is lubricated with grease for life (see FIGS. 3 to 5).

(11) In all embodiments of the drive system 1 according to the invention, the internal combustion engine 2 is communicatingly connected to an exhaust gas system 13 via an exhaust manifold 12, wherein in the exhaust gas system 13 an exhaust gas aftertreatment device 14, for example a filter or a catalytic converter is arranged.

(12) Looking at the drive system 1 according to FIG. 4, the same comprises both a first seal 6 and also a second seal 7, wherein additionally a drain pipe 15 is provided, which on the inlet side is connected to the power transmission device 5 and at the outlet side to the exhaust gas aftertreatment device 14 and via which the working medium can be drained from the power transmission device 5 into the exhaust gas aftertreatment device 14. In this case, a leakage of working medium from the expander 3, for example the axial piston machine or the turbine, additionally prevented from entering the internal combustion engine 2 by both the second seal 7 and also by the drain pipe 15.

(13) Looking at the drive system 1 according to FIG. 5, the same likewise comprises a first seal 6 and also a second seal 7, wherein at least the first seal 6 has to be present. In addition, the power transmission device 5 in this embodiment comprises a housing 22a, which is connected to the intake pipe 9 via a connection pipe 23 downstream of the air mass sensor 10. In this case, a leakage of the first seal 6 and thus an undesirable passing of working medium into the housing 22, 22a of the power transmission device 5 is also associated with an increase in power of the internal combustion engine 2 with the air mass flow remaining the same and can be detected.

(14) Independently of the selected embodiment, the housing 22, 22a of the power transmission device 5 is hermetically sealed relative to the crankcase 4 of the internal combustion engine 2 and the expander 3, so that even with a for example merely tubular housing 22, 22a a tight connection of the same both to the crankcase 4 and also the expander 3 is provided.

(15) Looking at the embodiment of FIG. 6 it is evident that the expander 3 is not directly mechanically coupled to the internal combustion engine 2 but arranged separately from the same and mechanically coupled, via a third seal 18, to a generator 19 for generating electric energy. The generator 19 comprises a generator housing 20 which is connected to the intake pipe 9 via a feed line 21 downstream of the air mass sensor 10. By way of this, a leakage of the third seal 18 and thus an undesirable passing of working medium into the housing 20 of the generator 19 and from the same via the feed line 21 into the intake pipe 9 is associated with an increase of power of the internal combustion engine 2 with the air mass flow remaining the same and can be detected and countermeasures taken if required. Countermeasure in this case is also a shutdown of the expander 3 by the engine control unit 11 which is communicatingly connected to the generator 19 and the expander 3.

(16) Looking for example at FIGS. 2 to 5, at least the first seal 6 is provided in each of these drive systems 1 and a working medium sensor 16 additionally arranged in the power transmission device 5. In this case, the engine control unit 11 is additionally designed in such a manner that it shuts off the expander provided that this working medium sensor 16 detects working medium, i.e. for example ethanol or cyclopentane in the power transmission device 5. This working medium sensor 16 can also trigger a premature shutdown of the expander 3 namely in a state in which the working medium has not entered the crankcase 4 of the internal combustion engine 2 by way of the second seal 7.

(17) Obviously, the working medium sensor 16 can also be provided with completely encapsulated power transmission device 5, as has been shown for example according to FIGS. 3 and 4. In the embodiment according to FIG. 4 it is additionally conceivable that the engine control unit 11 is designed in such a manner that the same switches off a valve 17, i.e. opens the same, provided the working medium sensor 16 detects working medium in the power transmission device 5 and consequently discharges the same via the drain pipe 15 into the exhaust gas aftertreatment device 14, for example the catalytic converter, where it is combusted.

(18) The power transmission device 5 can be designed for example as a transmission in particular also with a freewheel or as a clutch.

(19) Here, the drive device 1 according to the invention can be controlled or regulated via an associated operating method, wherein in the case of this operating method the engine control unit 11 detects a power of the internal combustion engine 2 and an air mass flow of the air mass sensor 10 and shuts off the expander 3 provided the detected power suddenly rises with the air mass flow otherwise remaining the same and because of this a passing of working medium from the expander 3 into the internal combustion engine 2 can be concluded.

(20) Such a passing of working medium, i.e. of combustible working medium, thus always points to a leakage of the first seal 6 and/or of the second seal 7 (see FIGS. 1 to 5), or of the third seal 18 (see FIG. 6), so that the operating method according to the invention initiates the failsafe mode. In the same manner or additionally or even alternatively, the engine control unit 11 with the operating method according to the invention can shut off the expander 3 provided the working medium sensor 16 detects working medium in the power transmission device 5.

(21) All embodiments of FIGS. 1 to 5 have in common that both the drive system according to the invention and also the operating method according to the invention make possible detecting an undesirable leakage of working medium and taking appropriate countermeasures, i.e. a shutdown of the expander 3 and thus at least minimising preferentially eliminating a further pressurised feeding of working medium into the internal combustion engine 2 or its crankcase 4 or the environment.