WO2010099941A1

WO2010099941A1 - Steam cycle process device

Info

Publication number: WO2010099941A1
Application number: PCT/EP2010/001307
Authority: WO
Inventors: Nickl JÖRG
Original assignee: Voith Patent Gmbh; Technische Universität Dresden
Priority date: 2009-03-04
Filing date: 2010-03-03
Publication date: 2010-09-10

Abstract

The invention relates to a steam cycle process device having a closed steam cycle. Said device comprises a reservoir for a liquid working medium, an evaporator for evaporating the liquid working medium, an expander for expanding the evaporated working medium, a condenser for liquefying the expanded vaporous working medium from the expander, and a working medium pump for supplying liquid working medium from the reservoir to the evaporator. The expander is designed as a steam engine. The steam engine comprises a housing and at least one cylindrical working chamber which is enclosed by the housing and in which a working piston can be moved by the vapor pressure. The steam engine further comprises an inlet for supplying live steam to the working chamber and an outlet for discharging exhaust steam from the working chamber. To this end, the inlet has an inlet valve. The inlet valve can be opened by way of an actuating element against a spring force. The actuating element is actuated at least indirectly by the working piston if said piston is in the region of the upper dead center.

Description

Steam cycle device

The invention relates to a Dampfkreisprozessvorrichtung with the features specified in more detail in the characterizing part of claim 1. Moreover, the invention relates to a drive device, which in each case has such a steam cycle device.

Steam engines having a steam powered piston are known in the art. Such steam engines are typically designed as relatively large and heavy units, which are primarily suitable for stationary use or use in rail vehicles or the like.

On the other hand, the prior art knows internal combustion engines, which accomplish the conversion of the energy supplied to them such as diesel, gasoline, gas or oil into mechanical energy. The known disadvantage of such internal combustion engines is now that the largest share of energy is released in the required combustion in the form of heat. This waste heat is derived via the cooling medium (water / air) and the exhaust gas flow from the internal combustion engine. In order to be able to use this energy flow, it has already been proposed to provide a steam engine in addition to the internal combustion engine. This represents a part of a closed steam cycle, which is advantageously supplied via the exhaust gas flow heat to a still high temperature level, via this heat input into an evaporator initially liquid working fluid is evaporated and then the steam engine is operated with this steam. In the steam engine while the vaporous working fluid is relaxed while performing mechanical energy. Subsequently, the working fluid in a condenser is re-liquefied and collected in a reservoir and then fed via a pump means for re-evaporation of the evaporator.

CON FL RMATION COPY Such a combination of internal combustion engine and steam engine can be seen for example from DE 196 10 382 C2, in which the operation of an internal combustion engine and a steam engine is described, wherein both drives act on a common crankshaft. Alternatively, it is described in this patent that the steam engine is also one of the

Combustion engine may have separate crankshaft, which may have a mechanical or fixed connection to the crankshaft of the internal combustion engine via a fixed or variable transmission.

In order to be able to use such a steam cycle device profitably in a drive unit, it is necessary that the system can be made correspondingly compact, lightweight and inexpensive. However, this contradicts the typical structure of a steam engine, since this alone has to be complicated because of its control.

It is therefore the object of the present invention to provide a Dampfkreisprozessvorrichtung, which can be made small, lightweight and compact. Moreover, it is the object of the invention to provide a drive unit, which can also be small, lightweight and compact.

This object is achieved by the Dampfkreisprozesvorrichtung with the features in the characterizing part of patent claim 1.

The steam cycle process device according to the invention uses a closed steam cycle with an evaporator and an expander to relax the vaporized working fluid, as well as a condenser for re-liquefying the expanded vaporous working fluid from the expander. The expander is constructed as a particularly lightweight and compact steam engine. This is achieved in that the inlet valve via an actuating element against a spring force is apparent and that this actuating element actuated at least indirectly by the working piston itself when it is in the region of top dead center, a steam engine with a very simple structure is created, which can be controlled by the movement of the working piston. The structure and in particular the control can therefore be carried out very simply, efficiently and small. This ultimately creates a simple and cost-effective design of the steam cycle device, which uses the exhaust heat of an internal combustion engine in a vehicle.

Furthermore, by a drive device, the object mentioned above is achieved by using the exhaust heat of an internal combustion engine to use a Dampfkreisprozessvorrichtung invention of the type just described.

In such a drive device, the small and compact design and in particular the simple control of the steam engine plays a particularly important role, since such devices are typically used in vehicles, especially in commercial vehicles. For a simple and easy construction is a decisive advantage, since permissible weight and space available are typically very limited. With the construction, however, the exhaust gas heat produced to a large extent can be used by being converted by the steam cycle device with the steam engine into mechanical energy, which can then be used to drive, for example, ancillary units or the like.

In a particularly advantageous embodiment of the drive unit, it is also provided that the internal combustion engine and the steam engine act at least indirectly on an output shaft.

The internal combustion engine and the steam engine can act in a conventional manner to a common crankshaft or via separate

Crankshafts, which are connected via a gear unit or the like, act together on an output. This has the advantage of being powered by the steam engine provided mechanical power can be used as drive power. On the other hand, the structure has the advantage that the steam engine can then build very small and compact, since he does not have to overcome his own starting torques, but can be started by either the internal combustion engine or provided for the internal combustion engine starting device accordingly.

Further advantageous embodiments of the invention, in particular also for the construction of the steam engine, will become apparent from the embodiment illustrated below and from the remaining dependent claims.

Showing:

Figure 1 shows a possible embodiment of a steam engine for the Dampfkreisprozessvorrichtung; and

FIG. 2 shows a drive device with the steam cycle device.

FIG. 1 shows a cross section through a steam engine 1, which is designed here as a steam engine 1 with a cylinder. Alternatively, a plurality of such cylinders may be combined in the manner known per se to form a multi-cylinder steam engine.

The steam engine 1 of Figure 1 shows a housing 2 and a cylinder space enclosed by the housing 3. In the cylinder chamber 3, a working piston 4 can be seen, which is designed in the known and proven design as a plunger. This working piston 4 is now articulated via a piston pin 5 with a connecting rod 6 schematically indicated here, which in turn is hingedly connected to a crankshaft 7. The steam engine 1 has in the region of a cylinder head 8, which in turn forms part of the housing 2, an inlet space 9, iri which through which an opening 10 live steam F can flow. In addition, the area of the Inlet 9 to an inlet valve 11, which consists essentially of a valve body 12 which is pressed by the force of a spring means 13 and supportive by the pressure of the live steam in the region of the inlet space 9 against a valve seat 14 and thus the inlet space 9 with respect to a working space 15th closes, which includes the working piston 4 in the cylinder chamber 3.

As is apparent from the position of the crankshaft 7 in Figure 1, the working piston 4 is in the state shown here before reaching the top dead center, which is then achieved when the articulated connection between the connecting rod 6 and the crankshaft 7 in the direction of the cylinder 3 points. Shortly before this top dead center of the working piston 4 is reached, this working piston abuts a plunger 16, which is arranged in the region of the cylinder head 8 facing piston surface, by a mechanical contact with the valve body 12 against the force of the spring means 13 and the pressure of the Main steam F in the region of the inlet space 9, so that this valve body 12 lifts from its valve seat 14. As a result, the energy-rich live steam F present with the appropriate pressure and corresponding temperature can flow through the opening 17, which is released from the valve body 12, along the plunger 16 into the working space and thereby press the working piston 4 in the direction of the crankshaft 7. In this case, mechanical energy is transmitted from the working piston 4 to the crankshaft 7 via the connecting rod 6 and the piston pin 5. Upon leaving the region of top dead center, the plunger 16 will simultaneously interrupt the mechanical contact with the valve body 12 so that it is pressed back into the valve seat 14 by the force of the spring device 13 and seals off the region of the inlet 9 with respect to the region of the working space 15.

As a result of the movement of the working piston 4 in the direction of the crankshaft 7, that is to say downwards in the illustrated example, the live steam F is correspondingly expanded while simultaneously outputting power to the working piston 4. Just before reaching the bottom dead center of the working piston 4, so if the articulated Connection of the connecting rod 6 to the crankshaft 7 on the side facing away from the working piston 4, the working piston 4 is driven so deep down in the cylinder chamber 3 that it releases openings 18 which are arranged in the outer surface of the cylinder chamber 3 in the housing 2. These openings 18 may, for example, as an opening or as more distributed over the circumference

Openings in the form of holes, slots or the like may be formed. Through these openings, which serve as an outlet for the relaxed exhaust steam A, flows a large part of the relaxed exhaust steam A according to the arrow A from the working space 15 from. The working piston 4 is then kept running by the further movement of the crankshaft 7 due to the inertia and / or other cylinders and moved back up, the residual steam is compressed. Shortly before the new top dead center is reached, the plunger 16 then opens the valve device 11 again by mechanical contact with the valve body 12 and the process described above begins again.

So we have it in this structure with a steam engine 1 in so-called Gleichstrombauart to do, since the flow of steam through the engine takes place from top to bottom and its flow direction is not reversed. This construction has the energetic advantage that the superheated steam always flows into the steam engine 1 via the inlet space 9 and flows out of the steam engine 1 via the openings 18. Thus, hotter steam is always available in the region of the inlet space 9, whereas comparatively cool steam arrives in the area of the openings 18. Unlike a countercurrent principle, therefore, the inlet region 9 is not cooled by cooled steam when ejected, but comes only with hot live steam F in combination. This improves the efficiency of the steam engine 1 in DC design over a steam engine in countercurrent design.

This construction also makes it possible to construct the steam engine 1 particularly simply, since in the region of the cylinder head 8 only elements for supplying steam, the so-called puffing, have to be provided, while for vapor removal, the so-called exhausts, the openings 18 in the region of the housing 2, and here in the region of the lateral surface of the cylinder 3, sufficient. This makes it possible to form a very simple and compact cylinder head 8, which only has to have the spring-loaded inlet valve 11. The operation of this intake valve 11 can, as described, carried out directly by a plunger 16 through the working piston 4. Since the working piston 4 and thus the plunger 16 in the region of top dead center has a comparatively low speed, the abutment of the plunger 16 on the valve body 12 to lift it from the valve seat 14, a bumping at a comparatively low speed. In addition, the spring-loaded

Inlet valve 11 are introduced via a suitable screw 22 by a closed by means of the screw 22 opening 23 in the cylinder head 8 and the inlet space 9. This is very simple in terms of structure and also allows easy accessibility and, if appropriate, easy replacement of the valve device 11.

In principle, however, it would also be conceivable to arrange the tappet 16 in a different manner and to realize this, for example, by carrying out several lever elements in a different manner. In particular, an off-center arrangement of inlet valve 11 and plunger 16 or optionally the plunger 16 replacing lever elements can be realized. This can make sense especially if the steam engine 1, not shown here, is designed as a single-acting machine, but if this, which would also be conceivable, has a double-acting piston. For this purpose, only on the side facing the crankshaft 7 of the working piston 4, a comparable structure should be realized, as on the cylinder head 8 facing side of the structure in Figure 1. Of course, then the working piston via a piston rod forces on a pivotally connected to the piston rod Transfer connecting rod. To carry out the piston rod by the second working space which then additionally arises below the working piston, a central position should be selected in order to avoid tilting of the working piston in the cylinder space. So that can at least in the region of the lower working space of the plunger and the inlet valve are no longer centrally located, so that this would have to be placed off-center. Even with such a construction with a double-acting working piston, it would be conceivable that only the corresponding inlets would be present on each side of the piston, in which case one or optionally two outlets could be realized centrally via corresponding openings in the lateral surface of the cylinder.

In order to realize practical conditions for operation in the single-acting structure described in FIG. 1, a relatively large dead space is necessary. This dead space, ie the volume which remains in the working space 15 when the working piston 4 is in its top dead center, will include in such a structure a corresponding amount of steam not streamed off. In order to obtain an acceptable mean indicated pressure in operation and to minimize the compression end pressure in the region of top dead center, it has been found that a dead space is suitable which has a volume which is greater than 10% of the cylinder displacement.

As already mentioned, the speed of the plunger during the bellowing of the valve body 12 and thus when opening the valve device 11 is relatively small, whereby only minimal loads occur. To further minimize these loads, it makes sense to limit the stroke of the intake valve 11 accordingly. It has proved to be particularly favorable when the lift of the inlet valve 11 and thus actually the stroke of the valve body 12 is less than 3% of the total stroke of the working piston 4.

Such a steam engine 1 can now be carried out correspondingly simple and small. It has its particular advantages when it is combined with a further engine, in particular an internal combustion engine 19, in a drive device 20. FIG. 2 shows such a drive device 20. The internal combustion engine 19 is included both act in the case shown here on a common crankshaft 7, which, however, can also be coupled together via an optionally indicated transmission unit 21 according to fixed or mechanically from two individual crankshafts.

For starting both the internal combustion engine 19 and the steam engine 1 may also be provided a known starting device, as is well known and common in internal combustion engines. By the direct or indirect coupling of the crankshaft 7 of the internal combustion engine 19 and the steam engine 1, both the internal combustion engine 19 and the steam engine 1 can be started by the starting device, which is not shown here. Alternatively, it would be conceivable to start the steam engine 1 via the internal combustion engine 19; for this purpose, the optional transmission device 21 would then have to be present in any case and in turn have a corresponding coupling device.

Furthermore, in the representation of the drive device 20, a steam cycle device 24 can be seen, which is designed with closed steam cycle. The steam cycle device 24 essentially comprises an evaporator 25 which in some way utilizes the exhaust heat of the internal combustion engine 19. In addition or instead of the use of heat from the exhaust gas of the internal combustion engine 19, it is of course also possible to use waste heat from other sources, for example, the waste heat from a charge air cooler, ancillary units or the like. The various waste heat streams can be introduced into the liquid of the steam cycle device 24 in parallel or serially one after the other.

In the steam cycle device 24, the vaporized liquid is then passed as live steam F into the steam engine 1, which is only schematically indicated here, and in this manner, as already described in detail above relaxed. The steam engine 1 thus represents the expander of the steam cycle process device 24. The effluent A flowing through the outlets of the steam engine 1 then passes into the region of a condenser 26 by being condensed again into liquid, which is then pumped into a reservoir 27 at a lower pressure level Example flows to ambient pressure. From the reservoir 27, the liquid can be fed back to the evaporator 25 in a manner known per se via a suitable working medium pump 28 as a working medium before the cycle begins again. In this way, exhaust heat of the internal combustion engine 19 can be used to be converted via the steam engine 1 into mechanical power. This mechanical power can then, as shown here, be supplied via a common crankshaft 7 to a drive, for example a utility vehicle, rail vehicle or the like. However, it would also be conceivable to drive corresponding ancillaries, alternators or the like via the drive power provided by the steam engine 1.

Claims

claims

A steam cycle closed loop steam cycle apparatus comprising: 1.1 a reservoir for a liquid working fluid;

1.2 an evaporator to evaporate the liquid working fluid;

1.3 an expander for relaxing the vaporized working fluid;

1.4 a condenser for liquefying the relaxed vaporous working fluid from the expander; and 1.5 a working fluid pump for supplying liquid working fluid from the

Reservoir to the evaporator; characterized in that 1.6 of the expander than at least one steam engine (1) with the following

Characteristics is formed: 1.7 at least one housing (2);

1.8 at least one of the housing (2) enclosed cylindrical working space (15);

1.9 for each working space (15) an inlet for supplying live steam in the working space (15); and 1.10 an outlet for removing exhaust steam from the working space (15);

1.11 a working piston (4) which is movable in the working space (15) by vapor pressure, wherein

1.12 the inlet has an inlet valve (11), wherein

1.13 the inlet valve (11) via an actuator against a spring force is apparent, and wherein

1.14 the actuator is at least indirectly actuated by the working piston (4) when it is in the range of top dead center.

2. steam cycle device according to claim 1, characterized in that the actuating element (plunger 16) as part of the working piston (4) is formed, which the inlet valve (11) by mechanical contact opens when the working piston (4) is in the region of top dead center.

3. Steam cycle device according to claim 1 or 2, characterized in that the outlet in the form of at least one opening (18) is formed, which is arranged so that the outlet is released in the region of the bottom dead center of the working piston.

4. steam cycle device according to claim 3, characterized in that the at least one opening (18) of the outlet is formed in a lateral surface of the working space.

5. steam cycle device according to one of claims 1 to 4, characterized in that the inlet valve (11) on the side of the working space (15) is arranged, in which the working piston (4) is in the region of top dead center.

6. steam cycle device according to claim 5, characterized in that the inlet valve (11) on the end face of the working space (15) is arranged.

7. steam cycle device according to one of claims 1 to 6, characterized in that the working piston (4) is designed as a plunger, which is connected via a piston pin (5) and a connecting rod (6) with a crankshaft (7) articulated.

8. steam cycle device according to one of claims 1 to 4, characterized in that the working piston (4) is designed as a double-acting working piston, wherein in each case at least one inlet valve is arranged on each of the end sides of the working space.

9. steam cycle apparatus according to claim 8, characterized in that the double-acting piston is arranged on a central push rod, wherein the push rod is pivotally connected to a connecting rod and articulated about this with a crankshaft.

10. steam cycle device according to one of claims 1 to 9, characterized by its design in Gleichstrombauart.

11. steam cycle device according to one of claims 1 to 10, characterized in that a top dead center of the working piston

(4) remaining dead space is more than 10% of the cubic capacity of the working space (15).

12. steam cycle device according to one of claims 1 to 11, characterized in that a lift of the inlet valve (11) less than

3% of the stroke of the working piston (4).

13. Drive device comprising:

13.1 an internal combustion engine; and 13.2 a steam engine; characterized in that

13.3 a steam cycle device (24) according to claim 1 to 12 is provided, which is designed such that the closed steam cycle for driving the at least one steam engine (1) waste heat from the exhaust gas of the internal combustion engine (19) can be fed.

14. Drive device according to claim 13, characterized in that the internal combustion engine (19) and the at least one steam engine (1) act at least indirectly on an output shaft.