DE102016218462A1 - Arrangement with a system for carrying out a thermodynamic cycle and an internal combustion engine, and method for operating such an arrangement - Google Patents

Abstract

The invention relates to an arrangement (1) with a system (3) for carrying out a thermodynamic cycle on a working medium, and with an internal combustion engine (5), wherein the internal combustion engine (5) is thermally operatively connected to the system (3), so that waste heat the internal combustion engine (5) in the system (3) for the thermodynamic cycle is usable, and wherein the system (3) with the internal combustion engine (5) is mechanically operatively connected such that mechanical work by the system (3) on the internal combustion engine (5 ) can be performed. The arrangement (1) is characterized by a pressure medium source (19) which can be fluidically connected to an expansion device (13) of the system (3) in a first operating state such that the expansion device (13) from the pressure medium source (19) is connected to a pressure medium can be acted upon, so that the expansion device (13) is driven in the first operating state by the pressure medium.

Description

The invention relates to an arrangement with a system for carrying out a thermodynamic cycle on a working medium and an internal combustion engine, and a method for operating such an arrangement.

Arrangements of the type discussed here have a system for carrying out a thermodynamic cycle on a working medium and an internal combustion engine, wherein the internal combustion engine is thermally operatively connected to the system, so that waste heat of the internal combustion engine in the system for the thermodynamic cycle is available. Such a system has, in particular, a working medium circuit which, in turn, has a working medium delivery device, in particular a feed pump, an evaporator, an expansion device and a condenser, viewed in the direction of flow of a working medium. By the working medium conveyor liquid working medium is preferably conveyed to the evaporator, in which the working medium absorbs heat and is evaporated. It is possible that the working fluid in the evaporator or downstream of the evaporator is overheated. The at least partially, preferably completely vaporous working medium passes from the evaporator to the expansion device, in which it is relaxed, doing mechanical work on the expansion device. In this case, the expansion device in particular converts thermal energy, pressure energy and / or flow energy of the working medium into mechanical energy, in particular rotational energy of an output shaft. The working medium expanded in the expansion device passes from this to the condenser, where it is cooled and preferably liquefied, after which it flows back again to the working medium conveyor, so that the working medium circuit is closed.

The internal combustion engine is in particular thermally connected to the evaporator of the working fluid circuit, so that the waste heat of the internal combustion engine can be used in the evaporator to heat the working fluid, in particular to evaporate. It is possible, for example, that waste heat from exhaust gas of the internal combustion engine is used, wherein in particular the evaporator can be acted upon with exhaust gas of the internal combustion engine. Alternatively or additionally, it is possible that waste heat from a coolant circuit of the internal combustion engine is used in the system, wherein in particular the coolant circuit may be fluidly connected to the evaporator.

With such an arrangement, it is possible for the system to be mechanically operatively connected to the internal combustion engine such that mechanical work can be performed by the system on the internal combustion engine. The waste heat of the internal combustion engine is thus converted by the system in particular again into mechanical power, which is then returned to the internal combustion engine and can support this in operation.

In known arrangements of the internal combustion engine is typically associated with a separate starter, in particular in the form of an electric machine which drives the internal combustion engine for starting. Such a starter causes additional costs, requires additional space and contributes in addition to the weight of the arrangement. This is not only disadvantageous, but especially in mobile applications of such arrangements. Although the expansion device is mechanically operatively connected to the internal combustion engine, it can not be used for starting the internal combustion engine, since it can only perform mechanical work when the working fluid circuit is heated by waste heat of the internal combustion engine. This is typically not the case when starting the internal combustion engine.

The invention has for its object to provide an arrangement with a system for performing a thermodynamic cycle on a working medium of the type discussed here and a method for operating such an arrangement, wherein said disadvantages do not occur.

The object is achieved by providing the subject matters of the independent claims. Advantageous embodiments emerge from the subclaims.

The object is achieved in particular by further developing an arrangement of the type described above in that it has a pressure medium source which can be fluidically connected to the expansion device of the system in a first operating state such that the expansion device from the pressure medium source can be acted upon by a pressure medium, so that the expansion device in the first operating state by the pressure medium - and in particular not by the working medium - is driven. This makes it possible, in particular, to drive the expansion device independently of a state of the working medium cycle by feeding it from the print medium source. This, in turn, makes it possible to use the expansion device for starting the internal combustion engine by being acted upon and driven by the pressure medium, in turn, the Internal combustion engine drives. In this way, it is possible to replace the starter by the expansion device, so that the starter can be completely eliminated. As a result, costs, space and weight can be saved. In particular, a synergy with respect to the use of the expansion device is created, because this not only used in the operation of the internal combustion engine for waste heat recovery, but can also be used to start the internal combustion engine. The expansion device is thus fed to a double use.

Accordingly, the first operating state is understood in particular as starting or starting the internal combustion engine. In particular, the working medium circuit is cold in the first operating state, which means that the working medium downstream of the evaporator is not in the form of a vapor and, thus, can not be used to drive the expansion device.

The pressure medium is preferably different from the working medium. In particular, it is possible for a gaseous substance or a gaseous substance mixture to be used as the pressure medium under normal conditions, that is to say in particular at 25 ° C. and 1013 mbar. This can be pressurized and / or pressurized in the print media source so that it can perform work on the expander.

The system is preferably set up to carry out an Organic Rankine cycle (ORC). Such a cycle is particularly suitable for waste heat utilization of internal combustion engines. Furthermore, the system is preferably set up for use of an organic substance or substance mixture as a working medium, in particular of ethanol, an ethanol-water mixture, or another organic working medium, for example a fluorohydrocarbon or a chlorofluorohydrocarbon.

The expansion device is preferably designed as a turbomachine, in particular as a turbine. Alternatively, the expansion device is preferably designed as a displacement machine or as a volumetric expansion device, in particular as a reciprocating piston engine, as a scroll expander, as a vane machine, or as a Roots expander. Particularly preferably, the expansion device is designed as a screw expander, in particular as an unsynchronized screw expander. Alternatively, it is also possible that the expansion device is designed as a synchronized or overhung screw expander.

The internal combustion engine is particularly preferably designed as a reciprocating engine. In particular, it is possible that it is designed as a two-stroke or four-stroke engine.

According to one embodiment of the invention, it is provided that the pressure medium source in a second operating state is fluidically separable from the expansion device. The second operating state preferably corresponds to a normal operation of the working fluid circuit, in which in particular the working fluid circuit is fluidically connected to the expansion device, thus in particular an operating state in which the working fluid circuit is hot, which means in particular that the working fluid at least partially, preferably completely vapor-shaped downstream of the evaporator , in particular at an evaporator outlet, and upstream of the expansion device. Furthermore, the second operating state preferably corresponds to an operating state in which the internal combustion engine is running. In this operating state, the pressure medium source is preferably separated from the expansion device, so that it can be acted upon in a defined manner with the working medium, wherein the pressure medium source and in particular the pressure medium does not disturb the normal operation of the working medium circuit and thus the system / disturb.

According to a development of the invention, it is provided that the arrangement has a valve device, by means of which in the first operating state a working medium path to the expansion device can be blocked and a pressure medium path can be released from the pressure medium source to the expansion device. In this way, it is possible to supply the expansion device in the first operating state defined only pressure medium and no working medium. In particular, as well as a loss of working fluid can be avoided from the working media cycle. The working media path is, in particular, a last section of a fluid line belonging to the working fluid circuit which leads to the expansion device. Preferably, the working medium circuit has a bypass path around the expansion device, wherein the working medium in the first operating state around the expansion device around - so bypassing the expansion device - can be passed along the working medium circuit when the working media conveyor is activated.

In the second operating state, the working medium path can preferably be opened by the valve device and the pressure medium path can be blocked. In this way, the expansion device in the second operating state with the working medium be acted upon, while avoiding exposure to pressure medium.

According to one embodiment of the invention it is provided that the arrangement has a discharge path, through which pressure medium from the expansion device can be derived. The pressure medium can thus be led away in a defined manner after flowing through the expansion device of this. It is preferably provided that the outflow path is fluidically separated from the working fluid circuit. This in turn ensures advantageously that the pressure medium can not get into the working fluid circuit, where it could affect its functioning, especially if gas bubbles would be entered into the working media circuit.

It is preferably provided that the pressure medium can be diverted through the outflow path from the expansion device into an environment of the arrangement. The particular gaseous pressure medium can therefore be released in a very simple manner in the environment.

According to one embodiment of the invention, it is provided that the pressure medium source is designed as a compressed gas source, in particular as a compressed air source. Particularly preferably, the pressure medium source is designed as a compressed gas storage, in particular as a compressed air storage. For example, the pressure medium source can be designed as a gas cylinder or as a different type of pressure accumulator for a gaseous medium. But it is also possible that the pressure medium source is designed as a compressor or as a pressure line, in particular in stationary applications of the arrangement, or in mobile applications in which a print media supply is already present, so that the expansion device via the pressure line or the compressor pressure medium can be fed. The embodiments of the print media source mentioned here are just as simple as they are cost-effective and thus particularly easy to implement. In many cases, an appropriate print media source is already present in the operating environment of such an arrangement anyway, which can be used to operate the device.

According to one embodiment of the invention it is provided that the expansion device is mechanically operatively connected to a crankshaft of the internal combustion engine. Such an operative connection can be made, in particular, via a gear mechanism, via a gear train of the internal combustion engine, in particular on the counterforce side, and / or in another suitable manner, which can be realized for example by gears, belts or chains. If the expansion device with the crankshaft of the internal combustion engine in mechanical operative connection, it can support the operation of the internal combustion engine in a particularly simple and effective manner, in particular by applying an additional torque, and they are also readily used for starting the internal combustion engine.

According to a particularly preferred embodiment, it is provided that the expansion device is mounted directly on the internal combustion engine. This is space-saving and at the same time creates a spatial proximity between the internal combustion engine and the expansion device, which can contribute to a particularly efficient use of the mechanical power of the expansion device in the internal combustion engine.

According to one embodiment of the invention, it is provided that the arrangement has a control device which is set up to fluidly connect the pressure medium source for starting the internal combustion engine with the expansion device. By means of the control device, it is therefore possible to start the internal combustion engine by the expansion device is driven by the pressure medium source.

The object is also achieved by providing a method for operating such an arrangement, in particular an arrangement according to one of the embodiments described above. It is provided in the context of the method that the expansion device of the system for starting the internal combustion engine is fluidly connected to the pressure medium source. The expansion device is then acted upon by the pressure medium and driven by the pressure medium, wherein the internal combustion engine is driven by the expansion device and thereby annealed. In particular, the advantages that have already been explained in connection with the arrangement are realized in connection with the method.

According to one embodiment of the invention, it is provided that the pressure medium source after starting the internal combustion engine is fluidly separated from the expansion device. In this way it can be prevented that the printing medium or the print medium source interferes with the normal operation of the expansion device in the system. Preferably, the working fluid circuit is connected after starting the internal combustion engine and in particular after separating the pressure medium source from the expansion device with the expansion device. It is possible that the working fluid circuit with the expansion device is only fluidically connected when it is sufficiently heated, especially if a predetermined overheating of the Working medium downstream of the evaporator, in particular at an evaporator outlet is reached. This means, in particular, that the expansion device is first charged with the working medium when the aforementioned condition is met.

According to one embodiment of the invention, it is provided that the working media path of the working fluid circuit of the system is fluidically separated from the expansion device when the pressure medium source is fluidically connected to the expansion device. In this way it can be avoided that the expansion device is acted upon at the same time with working medium and with pressure medium. Furthermore, it can be avoided that pressure medium enters the working fluid circuit.

The invention will be explained in more detail below with reference to the drawing. The single figure shows a schematic representation of an embodiment of an arrangement with a system for carrying out a thermodynamic cycle and an internal combustion engine.

The single FIGURE shows a schematic representation of an embodiment of an arrangement 1 that a system 3 for carrying out a thermodynamic cycle on a working medium and an internal combustion engine 5 having. Here is the internal combustion engine 5 with the system 3 thermally operatively connected, so that waste heat of the internal combustion engine in the system 3 can be used for the thermodynamic cycle. The system 3 in turn is with the internal combustion engine 5 mechanically operatively connected so that mechanical work through the system 3 on the internal combustion engine 5 can be performed.

In detail, it shows that the system 3 here a working media cycle 7 which, in turn - seen in the flow direction of the working medium in this order - a working media conveyor 9 , which is preferably designed as a pump, in particular as a feed pump, an evaporator 11 , an expansion device 13 and a capacitor 15 having. In this case, in particular liquid working medium through the working media conveyor 9 in the evaporator 11 promoted, where it absorbs heat and is evaporated. For this purpose, in particular, the evaporator 11 thermally with the internal combustion engine 5 operatively connected. In the illustrated embodiment, indicated by a dashed line that, for example, exhaust gas of the internal combustion engine 5 through the evaporator 11 can be passed, so that waste heat from the exhaust gas of the internal combustion engine 5 in the evaporator 11 can be used to heat the working medium. Additionally or alternatively, the system may also be configured to remove waste heat from a coolant circuit of the internal combustion engine 5 take.

The vaporized working fluid flows from the evaporator 11 to the expansion device 13 in which it is relaxed and does mechanical work. The expansion device 13 preferably has an output shaft 17 on, preferably with a crankshaft, not shown, of the internal combustion engine 5 is mechanically operatively connected, for example via a transmission, a gear drive or the like.

That in the expansion device 13 Relaxed working fluid continues to flow to the condenser 15 where it is cooled and preferably re-liquefied. From the condenser 15 the working fluid returns to the working fluid conveyor 9 so that the circuit is closed.

The embodiment of the arrangement shown here 1 has a print media source 19 on that with the expander 13 in a first operating state fluidly connectable such that the expansion device 13 from the print media source 19 can be acted upon with a pressure medium, so that the expansion device 13 is driven in the first operating state by the pressure medium. In this way, the expansion device 13 in particular as a starter for the internal combustion engine 5 be used by in the first operating state in which they can not yet be driven by the working medium, by the pressure medium from the print medium source 19 is driven. A separate starter for the internal combustion engine 5 can then be saved, so additional costs, additional space and additional weight for the arrangement 1 be avoided.

The print media source 19 is in a second operating state preferably fluidically from the expansion device 13 separable.

The order 1 has a valve device 21 on, through which in the first operating state a working media path 23 to the expansion device 13 lockable and a print media path 25 from the print media source 19 to the expansion device 13 is releasable. In the second functional position is preferred by the valve device 21 the working media path 23 releasable and the print media path 25 Lockout. The valve device 21 is particularly preferably designed as a three-way valve, which either - in the first operating state - the print media path 25 , or - in the second operating state - the working media path 23 with the expansion device 13 can connect, the other path is blocked by the three-way valve.

The working media cycle 7 preferably has a bypass path, not shown here for the working medium to the expansion device 13 along, along which the working medium along the working medium circuit 7 can flow when the working media path 23 to the expansion device 13 Is blocked.

Next, the arrangement 1 prefers a discharge path 27 through which the pressure medium from the expansion device 13 is derivable. Here is the discharge path 27 preferably from the working fluid circuit 7 separated, here specifically by another valve device 29 through which the expansion device 13 at its outlet either - in the first operating state - with the discharge path 27 or - in the second operating state - with the working fluid circuit 7 is connectable. Preferably, the other valve device is also 29 designed as a three-way valve.

The discharge path 27 is preferably with an environment 31 the arrangement 1 fluidly connected, so that the pressure medium from the expansion device 3 over the discharge path 27 in the nearby areas 31 can be dismissed. It is possible that the discharge path 27 in a vent path 33 can open, which has a safety valve 35 , which may be designed in particular as a pressure relief valve, with the working fluid circuit 7 connected is. If the pressure in the working fluid circuit increases 7 above a predetermined safety limit, the safety valve can 35 respond and working medium via the venting path 33 from the working media cycle 7 in the nearby areas 31 dismiss.

The print media source 19 is preferably designed as a compressed gas source, in particular as a compressed air source, preferably as a compressed gas reservoir, in particular as a compressed air reservoir. It is also possible that the print media source 19 is designed as a compressor or pressure line.

The expansion device 13 is preferably directly on the internal combustion engine 5 assembled.

Preferably, the arrangement 1 a control device 37 which is set to the print media source 19 for starting the internal combustion engine 5 fluidically with the expansion device 13 connect to. For this purpose, the control device 37 preferably with the valve device 21 and preferably with the further valve device 29 actively connected to this.

The order 1 is preferably operated so that the print media source 19 for starting the internal combustion engine 5 with the expansion device 13 fluidically connected, wherein the expansion device 13 is pressurized with the pressure medium and driven by the pressure medium, and wherein the internal combustion engine 5 from the expansion device 13 driven and tempered. The print media source 19 is after starting the internal combustion engine 5 fluidically from the expansion device 13 separated; In addition, the working medium cycle is preferred 7 , especially the working media path 23 , after starting the internal combustion engine 5 and especially when the working fluid is downstream of the evaporator 11 , in particular at an evaporator outlet, has reached a predetermined overheating, with the expansion device 13 connected.

The working media path 23 on the other hand is fluidically from the expansion device 13 disconnected when the print media source 19 fluidically - via the pressure medium path 25 - with the expansion device 13 connected is.

Overall, it turns out that with the arrangement proposed here 1 and the method a synergy in the sense of a double use of the expansion device 13 can be provided, which not only to the mechanical support of the internal combustion engine 1 but may be used in addition to tempering same. This can be a separate starter for the internal combustion engine 5 be replaced, so that costs, space and weight could be saved.

Claims (10)

Arrangement ( 1 ), with a system ( 3 ) for carrying out a thermodynamic cycle on a working medium, and with an internal combustion engine ( 5 ), wherein the internal combustion engine ( 5 ) with the system ( 3 ) is thermally operatively connected, so that waste heat of the internal combustion engine ( 5 ) in the system ( 3 ) is usable for the thermodynamic cycle, and wherein the system ( 3 ) with the internal combustion engine ( 5 ) is mechanically operatively connected such that mechanical work by the system ( 3 ) on the internal combustion engine ( 5 ), characterized by a print media source ( 19 ) equipped with an expansion device ( 13 ) of the system ( 3 ) is fluidically connectable in a first operating state such that the expansion device ( 13 ) from the print media source ( 19 ) is acted upon by a pressure medium, so that the expansion device ( 13 ) is driven in the first operating state by the pressure medium. Arrangement ( 1 ) according to claim 1, characterized in that the print medium source ( 19 ) in a second operating state fluidically from the expansion device ( 13 ) is separable. Arrangement ( 1 ) according to one of the preceding claims, characterized by a valve device ( 21 ), through which in the first operating state a working media path ( 23 ) to the expansion device ( 13 ) and a print media path ( 25 ) from the print media source ( 19 ) to the expansion device ( 13 ), wherein preferably in the second operating state the working media path ( 23 ) and the print media path ( 25 ) is lockable. Arrangement ( 1 ) according to one of the preceding claims, characterized by a discharge path ( 27 ), by the pressure medium from the expansion device ( 13 ) is derivable, wherein the outflow path ( 27 ) preferably from a working medium cycle ( 7 ) of the system ( 3 ) is disconnected. Arrangement ( 1 ) according to one of the preceding claims, characterized in that the print medium source ( 19 ) is formed as a compressed gas source, in particular as a compressed air source, preferably as a compressed gas reservoir, in particular as a compressed air reservoir. Arrangement ( 1 ) according to one of the preceding claims, characterized in that the expansion device ( 13 ) mechanically with a crankshaft of the internal combustion engine ( 5 ) is operatively connected. Arrangement ( 1 ) according to one of the preceding claims, characterized by a control device ( 37 ), which is set up to control the print media source ( 19 ) for starting the internal combustion engine ( 5 ) fluidically with the expansion device ( 13 ) connect to. Method for operating an arrangement ( 1 ) with a system ( 3 ) for carrying out a thermodynamic cycle on a working medium and an internal combustion engine ( 5 ), in particular according to one of claims 1 to 7, wherein: - for starting the internal combustion engine ( 5 ) an expansion device ( 13 ) of the system ( 3 ) fluidically with a pressure medium source ( 19 ), wherein - the expansion device ( 13 ) is acted upon by a pressure medium and driven by the pressure medium, and wherein - the internal combustion engine ( 5 ) from the expansion device ( 13 ) is driven and tempered. A method according to claim 8, characterized in that the pressure medium source after starting the internal combustion engine ( 5 ) fluidically from the expansion device ( 13 ) is separated. Method according to one of claims 8 and 9, characterized in that a working media path ( 23 ) of a working media cycle ( 7 ) of the system ( 3 ) fluidically from the expansion device ( 13 ) is disconnected when the print media source ( 19 ) fluidically with the expansion device ( 13 ) is connected.

Images