U.S. patent application number 13/812699 was filed with the patent office on 2013-05-16 for piston engine drivable using a steam power process.
This patent application is currently assigned to ROBERT BOSCH GMBH. The applicant listed for this patent is Nadja Eisenmenger, Hans-Christoph Magel, Andreas Wengert. Invention is credited to Nadja Eisenmenger, Hans-Christoph Magel, Andreas Wengert.
Application Number | 20130118174 13/812699 |
Document ID | / |
Family ID | 44278588 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130118174 |
Kind Code |
A1 |
Eisenmenger; Nadja ; et
al. |
May 16, 2013 |
PISTON ENGINE DRIVABLE USING A STEAM POWER PROCESS
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 (8) in the cylinder bore (5), a rod
(21) which is connected to the cylinder piston (6), and a bearing
point (37) on which the rod (21) and the cylinder piston (6)
connected to the rod (21) are mounted. A peripheral gap (28) is
predefined between the cylinder piston (6) and the cylinder bore
(5), thus preventing frictional wear between the cylinder piston
(6) and the cylinder bore (5), which is particularly advantageous
when a water-based working fluid is conducted through the operating
space (8) since steam has no lubricity.
Inventors: |
Eisenmenger; Nadja;
(Stuttgart, DE) ; Magel; Hans-Christoph;
(Reutlingen, DE) ; Wengert; Andreas; (Auenwald,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eisenmenger; Nadja
Magel; Hans-Christoph
Wengert; Andreas |
Stuttgart
Reutlingen
Auenwald |
|
DE
DE
DE |
|
|
Assignee: |
ROBERT BOSCH GMBH
Stuttgart
DE
|
Family ID: |
44278588 |
Appl. No.: |
13/812699 |
Filed: |
July 6, 2011 |
PCT Filed: |
July 6, 2011 |
PCT NO: |
PCT/EP2011/061416 |
371 Date: |
January 28, 2013 |
Current U.S.
Class: |
60/712 |
Current CPC
Class: |
F01B 9/023 20130101;
F01K 23/00 20130101 |
Class at
Publication: |
60/712 |
International
Class: |
F01K 23/00 20060101
F01K023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2010 |
DE |
102010038543.3 |
Claims
1. A piston engine (1) that can be driven using a steam power
process, with at least one cylinder bore (5), a cylinder piston (6)
arranged in the cylinder bore (5), which bounds a working chamber
(8) in the cylinder bore (5), a rod (21) at least indirectly
connected to the cylinder piston (6) and at least one bearing point
(37), on which the rod (21) and the cylinder piston (6) connected
to the rod (21) are supported, wherein a circumferential gap (28)
is defined between the cylinder piston (6) and the cylinder bore
(5) and wherein the rod (21) connects the cylinder piston (6) to a
crank loop (18).
2. The piston engine as claimed in claim 1, characterized in that
an external diameter (26) of an exterior (25) of the cylinder
piston (6) is defined to be smaller than an internal diameter (27)
of the cylinder bore (5).
3. The piston engine as claimed in claim 1, characterized in that
at least one sealing element (31, 32) is arranged on an exterior
(25) of the cylinder piston (6).
4. The piston engine as claimed in claim 3, characterized in that
at least one circumferential recess (29, 30) is formed on the
exterior (25) of the cylinder piston (6), that the sealing element
(31, 32) is formed as an annular sealing element (31, 32) and that
the annular sealing element (31, 32) is inserted in the
circumferential recess (29, 30).
5. The piston engine as claimed in claim 1, characterized in that
the rod (21) is at least essentially rigidly connected to the
cylinder piston (6), that the bearing point (37) is in the form of
a bearing bore (36) in which the rod (21) is guided, and that the
cylinder piston (6) is at least approximately centrally orientated
on a longitudinal axis (7) of the cylinder bore (5) by the guidance
of the rod (21) in the bearing bore (36).
6. The piston engine as claimed in claim 5, characterized in that
the bearing bore (36) is arranged in a housing part (35), which is
arranged between the cylinder bore (5) and a crankshaft chamber
(15).
7. The piston engine as claimed in claim 1, characterized in that a
crankshaft chamber (15) is provided, that the rod (21) is led out
of the cylinder bore (5) via the bearing point (37) into the
crankshaft chamber (15), that a crankshaft (16) is arranged in the
crankshaft chamber (15) and that the rod (21) works in conjunction
with the crankshaft (16) by means of the crank loop (18).
8. The piston engine as claimed in claim 1, characterized in that
at least one further cylinder bore (5'), a further cylinder piston
(6') arranged in the further cylinder bore (5') and which bounds a
further working chamber (8') in the further cylinder bore (5'), a
further rod (21'), which is at least indirectly connected to the
further cylinder piston (6'), and at least one further bearing
point (37') are provided, wherein the further rod (21') is
supported on the further bearing point (37') and wherein a
circumferential gap (28') is defined between the further cylinder
piston (6') and the further cylinder bore (5')
9. The piston engine as claimed in claim 8, characterized in that
the further rod (21') is at least substantially rigidly connected
to the further cylinder piston (6'), that the further bearing point
(37') is formed by a further bearing bore (36'), in which the
further rod (21') is guided, and that the further cylinder piston
(6') is at least approximately centrally orientated on a
longitudinal axis (7) of the further cylinder bore (5') by the
guidance of the further rod (21') in the further bearing bore
(36').
10. The piston engine as claimed in claim 8, characterized in that
an external diameter (26') of an exterior (25') of the further
cylinder piston (6') is defined to be smaller than an internal
diameter (27') of the further cylinder bore (5').
11. The piston engine as claimed in claim 8, characterized in that
an at least one sealing element (31', 32') is arranged on an
exterior (25') of the further cylinder piston (6').
12. The piston engine as claimed in claim 11, characterized in that
an external diameter (26') of an exterior (25') of the further
cylinder piston (6') is defined to be smaller than an internal
diameter (27') of the further cylinder bore (5').
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a piston engine that can be driven
using a steam power process. In particular, the invention relates
to a piston engine that can be driven using a steam power process
and that is used to utilize the waste heat of an internal
combustion engine.
[0002] Internal combustion engines convert the energy of the fuel
into mechanical energy for driving vehicles and similar. However, a
considerable portion of the energy is released as waste heat, which
is carried away from the internal combustion engine by the cooling
system or in the exhaust gas. In order to utilize this thermal
energy, it is conceivable that a steam power process is coupled to
the internal combustion engine. By this means the thermal energy
from the internal combustion engine can be used to generate steam,
which is expanded in an expansion machine and thus provides
additional energy, which can be used for driving the vehicle or for
generating auxiliary energy. Here, however, the problem arises that
the steam engine is driven by steam or a similar fluid from the
steam power process, which has no lubrication capability, which
promotes wear of the steam engine.
SUMMARY OF THE INVENTION
[0003] The piston engine according to the invention has the
advantage that advantageous operation of the piston engine is
possible, even when using water or other poorly lubricating working
fluids. This has the effect, inter alia, of reduced wear on the
cylinder piston and of a longer service life of the piston
engine.
[0004] It is advantageous that the piston engine, which can be
driven using the steam power process, is combined with an internal
combustion engine in order to convert the waste heat of the
internal combustion engine into additional drive energy using the
steam power process. Such a combination is particularly efficient
for waste heat utilization in a commercial vehicle, because here
the internal combustion engine produces great power and there is
thus a large quantity of heat available for generating steam. This
enables the fuel consumption to be reduced.
[0005] A piston engine with a Scotch-Yoke crank drive configured as
a reciprocating piston steam engine is of particular advantage,
especially for use in commercial vehicles with diesel engines or
gas engines. This enables approximately the same revolution rate
range to be achieved for the piston engine as for the internal
combustion engine and thus the mechanical energy produced by the
piston engine can be delivered directly to the crankshaft of the
diesel engine or gas engine. Such a piston engine can also be
conveniently mounted in the limited installation space on an
internal combustion engine.
[0006] The steam process is configured as an ORC process (Organic
Rankine Cycle Process) in an advantageous manner. Here the thermal
energy of the waste heat is converted into mechanical energy using
the ORC process. This enables the waste heat from an exhaust gas of
the internal combustion engine or an exhaust gas recovery means to
be transferred via a heat exchanger to the working fluid of the ORC
process in an advantageous manner. Here the working fluid can be
based at least substantially on water. The working fluid can be
evaporated at the heat exchanger. This steam can then be expanded
in the piston engine acting as an expansion machine, whereby the
mechanical energy is obtained. The working fluid is then cooled in
a condenser and supplied to a pump. The working fluid can thus be
compressed in the liquid phase by the pump to the pressure level
for renewed evaporation at the heat exchanger. This closes the
circuit.
[0007] By mounting the rod on the bearing point, the load on the
cylinder piston can be reduced in an advantageous manner. In
particular, transverse forces on the cylinder piston can be reduced
by said mounting, because they are absorbed by the bearing parts.
An external diameter of an exterior of the cylinder piston is
specified to be smaller than an internal diameter of the cylinder
bore in an advantageous manner here. This ensures that the cylinder
piston is not in direct contact with the cylinder bore acting as
the cylinder working surface and no force is transferred between
the cylinder piston acting as the working piston and the cylinder
bore (cylinder wall). The cylinder piston comprises an adequate
circumferential gap to the cylinder bore. A stable and well-guided
mounting for the cylinder piston can be achieved in connection with
the mounting on the rod, which also acts as transmission rod.
[0008] The occurrence of wear on the cylinder piston is
particularly critical, because it is operating with a poorly
lubricating working fluid (working medium). In particular, the
working piston can operate with steam, which has no lubrication
capability. The occurrence of such wear is prevented or at least
reduced by the gap between the cylinder piston and the cylinder
bore. At least one sealing element is advantageously arranged on
the exterior of the cylinder piston. Here it is also advantageous
that a circumferential recess is formed on the exterior of the
cylinder piston, that the sealing element is formed as an annular
sealing element and that the annular sealing element is inserted
into the circumferential recess on the exterior of the cylinder
piston. In particular, the circumferential recess on the exterior
of the cylinder piston can be formed by a circumferential annular
groove. This enables the sealing on the cylinder piston to be
advantageously enhanced in order to prevent or at least reduce
unwanted dispersal of the gaseous working fluid, especially the
steam, through the gap between the cylinder piston and the cylinder
bore. In order to enhance the sealing on the piston, special
additional sealing elements in the form of piston rings or similar
can be used here.
[0009] It is also advantageous that the rod is at least
substantially rigidly connected to the cylinder piston, that the
bearing point is formed by a bearing bore in which the rod is
guided and that the cylinder piston is centrally orientated at
least approximately on a longitudinal axis of the cylinder bore by
the guidance of the rod in the bearing bore. This enables an
advantageous support of the cylinder piston with respect to the
cylinder bore on the bearing parts by means of the rod. Wear on the
working piston can thereby be prevented over the service life of
the piston engine. The bearing bore can, for example, be formed on
a housing part that is arranged between the cylinder bore and a
crankshaft chamber. This enables an advantageous media separation
over the bearing bore. In particular, lubricating oil can be
provided in the crankshaft chamber in order to lubricate a
crankshaft and other components arranged in the crankshaft
chamber.
[0010] It is also advantageous here that the rod is led out of the
cylinder bore through the bearing point into the crankshaft
chamber, that the crankshaft is arranged in the crankshaft chamber
and that the rod works in conjunction with the crankshaft by means
of a crank loop.
[0011] It is also advantageous that at least one further cylinder
bore, a further cylinder piston arranged in the further cylinder
bore, which bounds a further working chamber in the further
cylinder bore, a further rod, which is at least indirectly
connected to the further cylinder piston, and at least one further
bearing point are provided, wherein the further rod is supported on
the further bearing point and wherein a circumferential gap is
defined between the further cylinder piston and the further
cylinder bore. It is also advantageous that the further rod is
essentially rigidly connected to the further cylinder piston, that
the bearing point is formed by a further bearing bore, in which the
further rod is guided, and that the further cylinder piston is at
least approximately centrally orientated on a longitudinal axis of
the further cylinder bore by the guidance of the further rod in the
further bearing bore. Here the further rod is preferably connected
to a crank loop arranged in the piston chamber. This enables an
advantageous crank loop drive to be implemented. In particular, it
is advantageous if both bearing points are lubricated with oil as
is the entire rest of the crank drive. In the oil region a stable
and well-guided bearing can thus be achieved. Here an additional
media separation can be provided that is directly connected to the
bearing points. An improved separation of the oil from the working
fluid can thus be achieved. Hence a particularly low-wear piston
engine with an oil-lubricated crank loop and with direct contact
between the cylinder piston and the cylinder wall of the cylinder
bore can be implemented. The mounting of the working piston on a
respective transmission rod without respective contact with the
cylinder bore can be used in an advantageous manner in piston
engines configured as reciprocating piston steam engines. However,
this design is particularly advantageous in a piston engine
configured as a reciprocating piston-steam engine with a crank loop
drive (Scotch Yoke).
[0012] An external diameter of an exterior of the further cylinder
piston is advantageously defined to be smaller than an internal
diameter of the further cylinder bore. It is also advantageous that
at least one sealing element is arranged on an exterior of the
further cylinder piston. A suitable design can be provided here, as
is also implemented with the cylinder piston.
BRIEF DESCRIPTION OF THE DRAWING
[0013] Preferred example embodiments of the invention are explained
in detail in the following description with reference to the
accompanying drawing. It shows:
[0014] FIG. 1 a piston engine in a schematic sectional illustration
corresponding to an example embodiment of the invention.
DETAILED DESCRIPTION
[0015] FIG. 1 shows a piston engine 1 in a schematic illustration
corresponding to an example embodiment of the invention. The piston
engine 1 is driven using a steam power process. The piston engine 1
can, for example, be used with an internal combustion engine of a
motor vehicle, in order to utilize the waste heat of the internal
combustion engine. The piston engine 1 converts the waste heat into
mechanical energy, which can be used, for example, as additional
drive energy for driving an auxiliary assembly, in particular an
electrical generator. The piston engine 1 according to the
invention is, however, also suitable for other applications. The
piston engine 1 of the example embodiment comprises a housing part
2 and cylinders 3, 4 connected to the housing part 2. A cylinder
bore 5, in which a cylinder piston 6 is arranged, is formed on the
cylinder 3. The cylinder bore 5 has a longitudinal axis 7, along
which the cylinder piston 6 can be displaced. The cylinder piston 6
bounds a working chamber 8 in the cylinder bore 5 on one side and a
depressurized chamber 9 on the other side.
[0016] A valve-controlled inlet 10 and a valve-controlled outlet 11
for the working chamber 8 are provided on the cylinder 3.
Compressed gaseous working fluid, in particular steam, can be fed
into the working chamber 8 via the valve-controlled inlet 10.
During expansion of the gaseous working fluid in the working
chamber 8, an operating force is exerted on the cylinder piston 6,
which leads to a displacement of the cylinder piston 6 in a
direction 12 along the longitudinal axis 7. The volume of the
working chamber 8 thus increases, whereas the volume of the
depressurized chamber 9 decreases. The depressurized chamber 9 is
connected via an outlet 13 to a low pressure region of the steam
circuit, so that working fluid passing into the depressurized
chamber 9 is fed back into the steam circuit.
[0017] A crankshaft chamber 15 is provided within the housing part
2. A crankshaft 16 with a crankshaft journal 17 is arranged in the
crankshaft chamber 15. A rotation axis of the crankshaft 16 is
orientated perpendicularly to the longitudinal axis 7 in this
case.
[0018] Moreover, a crank loop 18 is arranged in the crankshaft
chamber 15. The crank loop 18 comprises an oblong hole-shaped
recess 19, in which a slide block 20 is inserted. The slide block
20 is arranged on the crankshaft journal 17 in this case. The
cylinder piston 6 is connected via a rod 21 to the crank loop 18.
This forms a working connection between the cylinder piston 6 and
the crankshaft 16, so that the reciprocal movement of the cylinder
piston 6 is converted into a rotational motion of the crankshaft
16.
[0019] Moreover, the cylinder 4 of the piston engine 1 comprises a
further cylinder bore 5', in which a further cylinder piston 6' is
arranged. In this case the further cylinder piston 6' is guided
along the longitudinal axis 7 of the cylinder bore 5'. The
longitudinal axis 7 acts here as a common longitudinal axis 7 for
the two cylinder bores 5, 5' of the cylinders 3, 4.
[0020] The cylinder piston 6' bounds a further working chamber 8'
and a further depressurized chamber 9 in the cylinder bore 5'. In
this case a valve-controlled inlet 10' and a valve-controlled
outlet 11' for the further working chamber 8' are provided on the
cylinder 4. An outlet 13' for the depressurized chamber 9' is also
provided in order to feed back working fluid that is passing from
the working chamber 8' into the depressurized chamber 9' into the
steam circuit.
[0021] Gaseous working fluid can thus also be led through the
working chamber 8'. During the expansion of the gaseous working
fluid in the working chamber 8', the cylinder piston 6' is operated
opposite to the direction 12. The reciprocating motion of the
cylinder piston 6' is thus transferred via a further rod 21' to the
crank loop 18. Here the further rod 21' connects the cylinder
piston 6' to the crank loop 18.
[0022] The crank loop 18 is thus connected via the rod 21 to the
cylinder piston 6 on the one hand and via the rod 21' to the
cylinder piston 6' on the other hand. This makes possible the
optional operation of the crank loop 18 in and opposite to the
direction 12. A Scotch Yoke drive can thus be implemented in an
advantageous manner.
[0023] The cylinder piston 6 has an exterior 25. The cylinder
piston 6 has an external diameter 26 on the exterior 25. Moreover,
an internal diameter 27 of the cylinder bore 5 is defined. The
external diameter 26 of the cylinder piston 6 and the internal
diameter 27 of the cylinder bore 5 are matched to each other. The
external diameter 26 of the exterior 25 of the cylinder piston 6 is
hereby smaller than the internal diameter 27 of the cylinder bore
5. In this way, a gap 28 is defined between the exterior 25 of the
cylinder piston 6 and the cylinder bore 5. The defined gap 28
ensures a certain distance of the cylinder piston 6 from the
cylinder bore 5 during operation. A contact between the cylinder
piston 6 and the cylinder bore 5 is hereby prevented over the
entire stroke of the cylinder piston 6.
[0024] During operation of the piston engine 1 there is the problem
that the gaseous working fluid provided in the working chamber 8,
in particular the steam, has no or only poor lubrication
properties. Adequate lubrication of the cylinder piston 6 in the
cylinder bore 5 to prevent frictional wear cannot be guaranteed in
this way. However, frictional wear is prevented by the defined gap
28. Vaporous working fluid can thus pass from the working chamber 8
into the depressurized chamber 9 through the gap 28. However, said
working fluid is fed back through the outlet 13 into the steam
circuit.
[0025] Moreover, the cylinder piston 6 in this example embodiment
comprises annular circumferential recesses 29, 30. The
circumferential recesses 29, 30 are in the form of annular grooves
in this case. Annular sealing elements 31, 32 are inserted in the
annular grooves 29, 30. The annular sealing elements 31, 32 form a
seal between the working chamber 8 and the depressurized chamber 9
in relation to the defined gap 28.
[0026] In this example embodiment a housing part 35 is provided
that is connected to the cylinder 3. The housing part 35 is
arranged between the cylinder bore 5 of the cylinder 3 and the
crankshaft chamber 15. A bearing bore 36 is formed on the housing
part 35, which forms a bearing point 37 for the rod 21. The rod 21
is thus supported in the bearing bore 36, wherein the bearing bore
36 allows a movement of the rod 21 along the longitudinal axis 7.
Transverse forces that occur are absorbed by supporting the rod 21
on the bearing point 37. The sealing elements 31, 32 are thus
relieved of load and contact between the cylinder piston 6 and the
cylinder bore 5 is thus prevented. The cylinder piston 6 is
additionally guided by the sealing elements 31, 32 in the cylinder
bore 5. If there is a rigid connection of the rod 21 to the
cylinder piston 6, guidance by the sealing elements 31, 32 is not
necessary.
[0027] Accordingly the cylinder piston 6' also has an exterior 25'
having an external diameter 26'. Furthermore, the cylinder bore 5'
has an internal diameter 27'. In this example embodiment the
external diameters 26, 26' of the cylinder pistons 6, 6' are
specified to be equal. Moreover, the internal diameters 27, 27' of
the cylinder bores 5, 5' are also specified to be equal. A gap 28'
is thus also formed on the cylinder piston 6' between the exterior
25' and the cylinder bore 5'. The gap 28' prevents a direct contact
of the cylinder piston 6' and the cylinder bore 5'. Moreover,
circumferential recesses 29', 30' are provided on the cylinder
piston 6', in which annular sealing elements 31', 32' are inserted.
Furthermore, a housing part 35' is also provided, which is arranged
between the cylinder bore 5' and the crankshaft chamber 15. A
bearing bore 36', in which the rod 21' is supported, is formed on
the housing part 35'. The bearing bore 36' thus forms a bearing
point 37' for the rod 21'. An advantageous support for the cylinder
piston 6' can thus take place on the cylinder 4 by means of the rod
21' on the bearing point 37'.
[0028] In this example embodiment the two rods 21, 21' are rigidly
connected to the crank loop 18. A bilateral support of the crank
loop 18 on the bearing points 37, 37' is thus formed. Transverse
forces occurring during the transfer of the reciprocating motion of
the cylinder piston 6, 6' to the crankshaft 16 can thus be
advantageously absorbed at the bearing points 37, 37'.
[0029] This enables optimized support of the cylinder pistons 6, 6'
acting as working pistons 6, 6' of the piston engine 1, which is in
the form of a reciprocating piston-steam engine. Thus the cylinder
pistons 6, 6' are arranged opposite each other relative to the
crankshaft 16 in this example embodiment. The cylinder pistons 6,
6' apply their force to the crankshaft 16 via the crank loop drive.
The inlet 10 and the outlet 11 for the cylinder 3 and the inlet 10'
and the outlet 11' for the cylinder 4 are preferably
valve-controlled. The reciprocating piston movement of the cylinder
pistons 6, 6' is transferred to the crankshaft 16 by the crank loop
drive with the crank loop 18 and the slide block 20, which sits on
the crankshaft journal 17. The crank loop 18 of the crank loop
drive is supported by the rods 21, 21' on the bearing points 37,
37', wherein said support absorbs the transverse forces
occurring.
[0030] The support is formed in such a way that the cylinder
pistons 6, 6' do not contact their respective cylinder contact
surfaces, which are specified in the cylinder bores 5, 5', and do
not transfer any forces there. Thus critical wear is prevented on
these non-oil lubricated points. The piston engine 1 can thus
achieve the necessary service life expectancy.
[0031] In order to reliably prevent frictional wear, adequately
dimensioned gaps 28, 28' in relation to the cylinder working
surfaces are provided. On the other hand, in order to further
enhance the sealing on the cylinder pistons 6, 6', in this example
embodiment additional sealing elements 31, 32, 31', 32', in
particular piston rings 31, 32, 31', 32', are arranged on the
cylinder pistons 6, 6'.
[0032] Moreover, in this example embodiment the bearing bores 36,
36' are oil-lubricated. For this purpose the bearing bores 36, 36'
are provided immediately adjacent to the crankshaft chamber 15, so
that lubricating oil from the crankshaft chamber 15 can be used to
lubricate the bearing points 37, 37'. In order to prevent the
ingress of lubricating oil into the depressurized chambers 9, 9',
one or a plurality of sealing elements 38, 39, 38', 39' can be
placed adjacent to each bearing point 37, 37'. This can ensure
good, low-wear support of the crank loop 18.
[0033] The invention is not limited to the described example
embodiments.
* * * * *