WO2012013462A1

WO2012013462A1 - Piston engine drivable using a steam power process

Info

Publication number: WO2012013462A1
Application number: PCT/EP2011/061409
Authority: WO
Inventors: Nadja Eisenmenger; Hans-Christoph Magel; Andreas Wengert
Original assignee: Robert Bosch Gmbh
Priority date: 2010-07-28
Filing date: 2011-07-06
Publication date: 2012-02-02
Also published as: DE102010038546A1

Abstract

A piston engine (1) that can be driven using a steam power process and is used in particular for utilizing the waste heat from an internal combustion engine comprises a cylinder bore (5), a cylinder piston (6) which is arranged in the cylinder bore (5) and delimits an operating space (7) in the cylinder bore (5), and a rod (12) which is connected to the cylinder piston (6) and is guided out of the cylinder bore (5). A bearing point (17) is provided on which the rod (12) that is guided out of the cylinder bore (5) is mounted. The rod (12) can connect the cylinder piston (6) to a crankshaft (14) located in a crankshaft space (20). The fact that the rod (12) is mounted on the bearing point (17) reduces transverse forces acting on the cylinder piston (6), thus making it possible to reduce wear and increase service life.

Description

Description title

About a steam power process drivable piston engine prior art

The invention relates to a drivable via a steam power piston engine. Specifically, the invention relates to a piston engine which can be driven by a steam power process and serves to utilize the waste heat of an internal combustion engine.

Internal combustion engines convert the energy of the fuel into mechanical energy for driving vehicles and the like. As a result, however, a significant portion of the energy is released as waste heat, which is led away by the cooling system or in the exhaust gas from the internal combustion engine. To use this heat energy, it is conceivable that a steam power process is coupled to the internal combustion engine. In this way, the heat energy from the internal combustion engine can be used to generate steam, which is expanded in an expansion engine and thus provides further energy that can be used to drive the vehicle or to generate auxiliary energy. Here, however, there is the problem that the steam engine is driven by steam or the like from the steam power process, which has no lubricity, whereby a wear of the steam engine is promoted.

DISCLOSURE OF THE INVENTION The piston engine according to the invention with the features of claim 1 has the advantage that an advantageous operation of the piston engine is also possible when using water or other, poorly lubricating working fluids. This has an effect, inter alia, on improved efficiency and a longer service life of the piston engine.

The measures listed in the dependent claims are advantageous

Further developments of the piston machine specified in claim 1 possible. Advantageously, the piston engine can be combined with an internal combustion engine to convert the waste heat of the internal combustion engine into additional drive energy. Such a combination for waste heat utilization is particularly efficient in a commercial vehicle, since here the internal combustion engine gives off a large power and thus a large amount of heat for steam generation is available. As a result, the fuel consumption can be reduced.

Especially for use in commercial vehicles with diesel engine or gas engine is designed as a reciprocating steam engine piston engine with Scotch-yoke crank mechanism of particular advantage. This can be about the same speed range for the

Piston engine as can be achieved for the internal combustion engine and thus the mechanical energy emitted by the piston engine directly to the crankshaft of the

Diesel engine or gas engine are delivered. In addition, such a piston engine can be conveniently mounted in a limited space on an internal combustion engine.

Advantageously, the steam process can be configured as an ORC process (Organic Rankine Cycle Process). The thermal energy of the waste heat is converted into mechanical energy via the ORC process. In this case, the waste heat from an exhaust gas of the internal combustion engine or an exhaust gas recirculation can be transmitted via a heat exchanger to the working fluid of the ORC process in an advantageous manner. The working fluid may in this case be based at least essentially on water, alcohol or a mixture of the two. At the heat exchanger, the working fluid can be evaporated. This steam can then be expanded in the piston machine serving as an expansion machine, whereby the mechanical energy is recovered. The working fluid is then cooled in a condenser and fed to a pump. The working fluid can thereby be compressed in the liquid phase by the pump to the pressure level for re-evaporation at the heat exchanger. As a result, the cycle is closed.

It is advantageous that the rod connected to the cylinder piston in a

Crankshaft space is guided and that the bearing between the cylinder bore and the crankshaft space is arranged. The crankshaft space can in this case be filled at least partially with an oil serving as a lubricant. About the oil from the crankshaft space a certain lubrication of the bearing is possible. In this case, the bearing point advantageously adjoins the crankshaft space. It is also advantageous that at least one sealing element is provided, which is arranged at the bearing point, and that the sealing element forms a seal between the bearing point and the cylinder bore. As a result, a media separation between the working fluid of the steam power process and the lubricant for the bearing can be formed. Specifically, a seal against the lubricant from the crankshaft space, which also lubricates the bearing, be formed. Thus, an advantageous separation on the one hand of the working fluid and on the other hand the lubricant is possible. It is also advantageous in this case that the cylinder piston on the one hand limits the working space and on the other hand a pressure-relieved space, that the rod extends through the pressure-relieved space and that the bearing point with the lubricating oil from the crankshaft space is lubricated. The pressure-relieved room is a further separation of the working space and thus provided in the work space,

vaporous working fluid and the crankshaft space and thus the lubricating oil possible. Specifically, the under a certain pressure, vaporous working fluid is not performed directly to the bearing or provided in front of the bearing seal when it escapes due to leakage or the like on the cylinder piston from the working space. Thus, the media separation between the working fluid and the lubricating oil can be further improved. This is also an intrusion of

Water vapor prevented or at least reduced to the bearing. On the other hand, penetration of the lubricating oil is prevented in the working space or at least avoided. It is also advantageous that the bearing is formed by a bearing bush and that guided out of the cylinder bore rod is guided through the bearing bush. The bearing bush can be formed from a suitable material. By the

Bearing bush can be reduced advantageously occurring lateral forces on the cylinder piston. Thus, improved storage and reduced wear can be achieved.

Advantageously, the rod is on the one hand connected to the cylinder piston and on the other hand at least indirectly connected to a crankshaft, wherein the rod forms a frictional connection between the cylinder piston and the crankshaft. In this case, the bearing point is advantageously configured such that it at least substantially absorbs transverse forces transmitted by the crankshaft to the rod. In particular, when using a scotch yoke drive for the piston engine can thus take place an advantageous storage of a crank loop of the scotch yoke drive. Since the cylinder piston with a poorly lubricating working fluid works, especially with water vapor, which has no lubricity, a bearing of the crank loop on the cylinder piston is critical, especially with respect to friction forces occurring and the associated wear, which adversely affects the efficiency and the life. Thus, the storage of the crank loop at the bearing, in particular a bearing bush, and thus not directly on the cylinder piston of particular advantage. Here, the storage on the rod from the cylinder piston to the crank loop. By this storage, the lateral forces are reduced to the cylinder piston and thus increases the life. When mounted on the rod also simple bushings made of a suitable material can be used in order to achieve improved storage and reduced wear.

In particular, it is advantageous if the bearing is lubricated with oil, as is possible for the rest of the crank mechanism. This oil-lubricated is particularly advantageous

Storage on the rod used as a transmission rod in combination with a media separation, which is possible via the arranged directly at the bearing seal. This can be realized in such a piston engine a good oil-lubricated storage of the crank grinding. It is also advantageous that at least one further cylinder bore, another cylinder piston arranged in the cylinder bore, has a cylinder bore in the cylinder bore

Working space limited, another rod which is at least indirectly connected to the other cylinder piston, and at least one further bearing point are provided, wherein the further rod is guided from the further cylinder bore, wherein the guided from the further cylinder bore rod is mounted at the further bearing point , wherein a crankshaft is provided, wherein the cylinder bore and the other

Cylinder bore with respect to a rotation axis of the crankshaft are arranged opposite to each other and wherein the crankshaft on the one hand at least indirectly connected to the rod and on the other hand at least indirectly connected to the other rod. It is also advantageous that a crank loop is provided, that a arranged on the crankshaft sliding block is provided, which is inserted into a slot-shaped recess of the crank loop, on the one hand, the rod connecting the cylinder piston with the crank loop and on the other hand, the other Stake the rest

Cylinder piston with the crank loop connects. This can be an advantageous

Power transmission to the crankshaft and an alternate operation of the two cylinder pistons are achieved. In addition, in a compact embodiment of the reciprocating engine, an advantageous energy recovery can be made possible. Brief description of the drawings

Preferred embodiments of the invention are described in the following description with reference to the accompanying drawings, in which corresponding

Elements are provided with matching reference numerals, explained in more detail. It shows:

Fig. 1 shows a piston machine in a schematic sectional view according to a first embodiment of the invention and Fig. 2 shows a piston machine in a schematic sectional view according to a second embodiment of the invention.

EMBODIMENTS OF THE INVENTION FIG. 1 shows a piston engine 1 in a schematic representation according to a first exemplary embodiment of the invention. The piston engine 1 is driven by a steam power process. Here, the piston engine 1 can be used especially in an internal combustion engine of a motor vehicle to use the waste heat of the internal combustion engine. The piston engine 1 then converts the waste heat into mechanical energy, which can serve, for example, as additional drive energy or for driving an auxiliary aggregate, in particular an electric generator. However, the piston engine 1 according to the invention is also suitable for others

Use cases. The piston engine 1 has a housing part 2 and cylinders 3, 4 connected to the housing part 2. Here, the cylinder 3 has a cylinder bore 5 in which a

Cylinder piston 6 is arranged. The cylinder piston 6 limited in the cylinder bore 5 on the one hand a working space 7 and on the other hand, a space 8. The space 8 can serve as a working space or as a pressure-relieved space.

On the cylinder 3, a valve-controlled inlet 9 and a valve-controlled outlet 10 are provided for the working space 7. Via the inlet 9 compressed, gaseous working fluid, in particular water vapor, can be guided into the working space 7. When relaxing the gaseous working fluid in the working chamber 7, an actuating force is exerted on the cylinder piston 6, which acts in a direction 1 1. The cylinder piston 6 is connected via a rod 12 indirectly with a crankshaft journal 13 of a crankshaft 14. As a result, the force can be transmitted from the cylinder piston 6 to the crankshaft journal 13. In addition, a valve-controlled inlet 15 and a valve-controlled outlet 16 may be provided for the space 8. In this embodiment, compressed, gaseous working fluid can also be introduced into the space 8 in order to relax it and thereby actuate the cylinder piston 6 counter to the direction 1 1. The control of the intake valves 9, 15 and the exhaust valves 10, 16 can in this case be carried out in a suitable manner to achieve an alternate actuation of the cylinder piston 6.

The rod 12 is mounted on a bearing 17. In this embodiment, the bearing 17 is formed by a bearing bush 18 which is inserted into a housing part 19 and connected thereto. The rod 12 extends through both the space 8 and through the bearing bush 18 at the bearing point 17. Here, the rod 12 extends into a crankshaft space 20 in the housing part 2, in which the crankshaft 14 is arranged. In operation is located in the crankshaft space 20, a lubricant, in particular an oil. Here, the crankshaft space 20 may be connected to a lubricant circuit. From the crankshaft space 20 ago some lubrication of the bearing bush 18 is possible to supply the storage of the rod 12 in the bearing bush 18 with the oil. As a result, frictional forces between the bearing bush 18 and the rod 12 are reduced. In the crankshaft space 20, a crank loop 21 is arranged in this embodiment, which has a slot-shaped recess 22. In this recess 22, a sliding block 23 is inserted, which is slidably mounted in the recess 22. The sliding block 23 is in this case arranged on the crankshaft journal 13 of the crankshaft 14 in order to enable an operative connection between the crankshaft journal 13 and the crank loop 21. As a result, a connection of the rod 12 via the crank loop 21 and the sliding block 23 is formed with the crankshaft journal 13.

The further cylinder 4 is designed according to the cylinder 3. In this case, the further cylinder 4 has a further cylinder bore 5 ', a further cylinder piston 6' arranged in the cylinder bore 5 ', a further working space 7' delimited by the cylinder piston 6 and a further space 8 'bounded by the cylinder piston 6. Furthermore, a valve-controlled inlet 9 'and a valve-controlled outlet 10' are provided for the further working space T. When relaxing one in the other

Working space T introduced compressed, gaseous pressurized fluid is an actuation of the cylinder piston 6 'against the direction of 1 1'. Since the cylinder piston 6 'via another rod 12' is also connected to the crank loop 21, the work

Cylinder piston 6, 6 'thereby against each other. Furthermore, a valve-controlled inlet 15 'and a valve-controlled outlet 16' are provided for the space 8 '. The rod 12 'is mounted on a bearing 17' in a further bearing bush 18 '. The bearing bush 18 'is in this case inserted into a housing part 19' and connected thereto. Thus, a piston machine 1 can be realized with a Scotch-Yoke crank mechanism, in which serving as a transmission rods rods 12, 12 'at the bearings 17, 17' are mounted. In this case, the cylinder pistons 6, 6 'are arranged opposite one another and transmit their force to the crankshaft 14 via the crank-wheel drive. By the crank grinding with the crank loop 21 and the sliding block 23, which sits on the crankshaft journal 13, the reciprocating piston movement of the cylinder piston 6, 6 'is transmitted to the crankshaft 14.

The crank loop 21 is mounted on the rods 12, 12 'at the bearings 17, 17'. In this case, bearing bushes 18, 18 'are used in this embodiment. It can also be provided in each case a plurality of bearing bushes. As a result of this mounting, the transverse forces on the cylinder pistons 6, 6 'are reduced. This increases the life of the cylinder piston 6, 6 '. This mounting of the crank loop 21 is particularly with a designed as a two-cylinder steam engine piston engine 1 with opposite

Cylinder piston 6, 6 'of advantage, since the torques occurring in this case

Crank loop 21 can be well supported.

Fig. 2 shows the piston machine 1 shown in Fig. 1 according to a second embodiment. In this embodiment, the bearings 17, 17 'for supporting the rods 12, 12' are formed directly on the housing parts 19, 19 '. Separate bushings, as provided in the embodiment shown in FIG. 1, can be omitted hereby. Further, seen from the crankshaft space 20 from behind the bearings 17, 17 'are each two sealing elements 24, 25 and 24', 25 'are arranged. The sealing elements 24, 25 and the sealing elements 24 ', 25' are designed annular, which on the one hand surround the rod 12 and on the other hand the rod 12 'on its outer side. The sealing elements 24, 25 form a seal between the space 8 and the bearing 17. According to the sealing elements 24 ', 25' form a seal between the space 8 'and the bearing 17'. This is a

Media separation between the lubricating oil from the crankshaft space 20 and the

Working fluid, which is optionally provided in the spaces 8, 8 ', improved.

In addition, the spaces 8, 8 'in this embodiment are designed as pressure-relieved spaces. Inlets for the spaces 8, 8 ', as they are formed in FIG. 1 by inlets 15, 15', are omitted here. The outlets 16, 16 'are here with a Low pressure range of the steam circuit connected to due due to leakage from the working spaces 7, 7 'in the spaces 8, 8' reaching working fluid returned to the steam circuit. By the pressure-relieved spaces 8, 8 ', the media separation is further improved. Because between the working spaces 7, 7 ', through which the vaporous

Working fluid is guided, and the crankshaft space 20 thereby a multi-stage separation is formed, which has the bearings 17, 17 ', the sealing elements 24, 25, 24', 25 'and the spaces 8, 8' as separation stages.

Thus, the bearings 17, 17 'are located specifically in this embodiment in the oil area and it can be a particularly good lubrication with oil. By directly to the bearings 17, 17 'adjoining sealing elements 24, 25, 24', 25 'an advantageous sealing of the oil region is made possible. This can be a good and

low-wear storage of the crank loop 21 can be ensured. The sealing elements 24, 25, 24 ', 25' for separating the lubricating oil from the working fluid in the spaces 8, 8 'are preferably arranged directly after the bearings 17, 17' on the rods 12, 12 'and have a smaller inner diameter than the cylinder piston 6, 6 'on. This reduces the frictional losses on the sealing elements 24, 25, 24 ', 25'.

In this case, one or more sealing elements 24, 25, 24 ', 25' can be provided in each case.

The invention is not limited to the described embodiments.

Claims

claims

1 . Piston engine (1), which is drivable via a steam power process, in particular for utilizing the waste heat of an internal combustion engine, with at least one cylinder bore (5), in the cylinder bore (5) arranged in the cylinder piston (6) in the

Cylinder bore (5) defines a working space (7), an at least indirectly with the cylinder piston (6) connected rod (12) which is guided out of the cylinder bore (5), and at least one bearing point (17), at which from the cylinder bore (5) guided rod (12) is mounted, wherein a crank loop (21) is provided and wherein the rod (21) connects the cylinder piston (6) with the crank loop (21).

2. Piston engine according to claim 1,

characterized,

in that the rod (12) connected to the cylinder piston (6) is guided into a crankshaft space (20) and that the bearing point (17) is arranged between the cylinder bore (5) and the crankshaft space (20).

3. piston machine according to claim 2,

characterized,

the bearing (17) can be lubricated with a lubricant.

4. piston machine according to claim 3,

characterized,

the bearing (17) can be lubricated with a lubricating oil from the crankshaft space (20).

5. Piston machine according to one of claims 1 to 4,

characterized,

in that at least one sealing element (24, 25) is provided, which is arranged at the bearing point (17), and that the sealing element (24, 25) forms a seal between the

Bearing (17) and the cylinder bore (5) forms.

6. Piston engine according to one of claims 1 to 5,

characterized, in that the bearing point (17) is formed by a bearing bush (18) and that the rod (12) guided out of the cylinder bore (5) is guided through the bearing bush (18).

7. Piston machine according to one of claims 1 to 6,

characterized,

in that the rod (12) is at least indirectly connected to a crankshaft (14) and that the rod (12) forms a frictional connection between the cylinder piston (6) and the crankshaft (14).

8. piston engine according to claim 7,

characterized,

in that the bearing point (17) is designed to at least substantially absorb transverse forces transmitted by the crankshaft (14) to the rod (12).

9. Piston machine according to one of claims 1 to 8,

characterized,

that at least one further cylinder bore (5 '), another in the other

Cylinder bore (5 ') arranged cylinder piston (6'), in the further cylinder bore (5 ') defines a further working space (7'), another rod (12 '), at least indirectly connected to the other cylinder piston (6') is, and at least one further bearing point (17 ') are provided, wherein the further rod (12') from the other

Cylinder bore (5 ') is guided, wherein the out of the further cylinder bore (5') guided rod (12 ') at the further bearing point (17') is mounted, wherein a crankshaft (14) is provided, wherein the cylinder bore (5) and the further cylinder bore (5 ') with respect to the crankshaft (14) are arranged opposite to each other and wherein the crankshaft (14) on the one hand at least indirectly with the rod (12) and on the other hand at least indirectly connected to the further rod (12').

10. piston engine according to claim 9,

characterized,

in that a sliding block (23) arranged on the crankshaft (14) is provided, which is inserted into a slot-shaped recess (22) of the crank loop (21) such that on the one hand the rod (12) engages the cylinder piston (6) with the crank loop ( 21) connects and that on the other hand, the further rod (12 ') connects the other cylinder piston (6') with the crank loop (21).

1 piston machine according to one of claims 1 to 10,

characterized, a working fluid of the steam power process is based on water, alcohol or a mixture of water and alcohol, whereby vaporous working fluid for actuating the cylinder piston (6) in the working space (7) can be relaxed.