WO2006013380A1 - A linear free piston stirling machine - Google Patents
A linear free piston stirling machine Download PDFInfo
- Publication number
- WO2006013380A1 WO2006013380A1 PCT/GB2005/003075 GB2005003075W WO2006013380A1 WO 2006013380 A1 WO2006013380 A1 WO 2006013380A1 GB 2005003075 W GB2005003075 W GB 2005003075W WO 2006013380 A1 WO2006013380 A1 WO 2006013380A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- power piston
- resilient member
- contact
- piston
- exceeds
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G1/00—Hot gas positive-displacement engine plants
- F02G1/04—Hot gas positive-displacement engine plants of closed-cycle type
- F02G1/043—Hot gas positive-displacement engine plants of closed-cycle type the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
- F02G1/0435—Hot gas positive-displacement engine plants of closed-cycle type the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines the engine being of the free piston type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G2275/00—Controls
- F02G2275/20—Controls for preventing piston over stroke
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G2280/00—Output delivery
- F02G2280/10—Linear generators
Definitions
- the present invention relates to a linear free piston Stirling machine.
- a machine may be an engine, for example, for use in a domestic combined heat and power system, or may be a cooler for a refrigerating system.
- the displacer and power piston within the free piston machine are tuned as a mechanical spring-mass-damper resonators which reciprocate independently.
- a flexible rod the lower end of which is fastened to a planar spring located in a lower dome of the machine, passes through the centre of the piston and is connected to the lower part of the displacer.
- the secondary magnets produce a magnetic spring which keeps the amplitude of reciprocation within the required limits.
- the inclusion of the magnets reduces the efficiency of the system due to a reduction in the density of magnetic flux produced by the field magnets, caused by fringing fields extending above and below the spring magnets.
- An alternative approach adopted in GB 2136087 is to use a spring attached to the reciprocating body. This has .the disadvantage of increasing the mass which is to be reciprocated.
- a further alternative is to use a gas spring as shown in DE 1 953 8422 and JP 4047150 to provide a cushioning effect.
- these reduce the efficiency of the engine as, in order to exert sufficient force to prevent collisions, the gas spring forces must start to act at a point where overstroke is not a risk. This unnecessary expenditure of energy will reduce the efficiency of the design.
- a linear free piston Stirling machine comprising a displacer and a power piston which are reciprocally mounted within a casing; an alternator electromagnetically coupled, in use, with the power piston; and an overstroke prevention mechanism which is fixed with respect to the casing and which comprises at least one resilient member, wherein the power piston comes into contact with the overstroke prevention mechanism when its displacement exceeds a predetermined level .
- the overstroke prevention mechanism can be used only to prevent overstroking in one direction as this may be sufficient in certain circumstances, or it is possible to use some different overstroke prevention mechanisms to prevent overstroking in the opposite direction.
- the power piston comes into contact with the overstroke prevention mechanism when its displacement exceeds a predetermined level in either direction of reciprocation of the power piston. Such an arrangement can prevent overstroking in either direction.
- the overstroke prevention mechanism comprises a resilient member, wherein the power piston is provided with a first portion which is arranged to contact the resilient member if the displacement of the power piston exceeds the predetermined level in a first direction, and a second portion which is arranged to contact the resilient member if the displacement of the power piston exceeds the predetermined level in a second direction.
- the single resilient member or a single group of resilient members prevent overstroking in both directions. This may be achieved either by providing the first and second portions in a recess within the power piston, or alternatively, providing the first and second portions on a separate component which projects from the power piston.
- the overstroke prevention mechanism may comprise a first resilient member which is arranged to contact the power piston if the displacement of the power piston exceeds the predetermined level in a first direction and a second resilient member which is arranged to contact the power piston if the displacement of the power piston exceeds the predetermined level in a second direction.
- Such a mechanism is more complex than the mechanism referred to above for the single resilient member or group of resilient members. However, there may be circumstances under which this would be the preferred option.
- Figure 1 is a schematic view of the various components in the base of the Stirling machine (left hand side only) ;
- Figure 2 is a plan of the resilient member of Figure 1;
- Figure 3 shows a portion of the Stirling engine incorporating a second example of a resilient mechanism
- Figure 4 is a schematic view of the resilient mechanism of Figure 3 in greater detail .
- the structure and operation of a linear free piston Stirling machine is well-known in the art and will not be described in detail here.
- a displacer piston (not shown) is connected to a flexible rod 1 as shown in Figure 1 which extends along the axis 2 of the machine.
- the machine is generally symmetrical about axis 2, although the right hand side is not shown in Figure 1.
- the flexible rod 1 is connected at its lower end to a pair of planar springs 3 which provide a restoring force to the displacer.
- the rod 1 extends through the centre of power piston 4, the left-hand portion of which is shown in Figure 1.
- the magnet drum 5 to which magnets 6 are attached is attached to reciprocate with the power piston.
- the magnets 6 reciprocate in the gap 7 within the alternator pack 8 which is fixed with respect to the machine housing.
- the overstroke mechanism is a resilient member 10 which is shown in detail in Figure 2.
- This has an annular configuration and has a number of mounting holes 11 for mounting to the machine casing.
- a number of resilient tongues 12 project radially inwardly and are provided with holes 13.
- a spring contact peg 14 projects through each of these holes 13.
- the spring contact peg 14 is provided with a lower flange 15 and an upper flange 16.
- a number of further resilient tongues 17 are provided between the resilient tongues 12 these provide extreme one way stops.
- Four spring contact pegs 14 are contemplated and this is the optimum number. However, this example could be made to work with only two pegs positioned on opposite sides of the resilient member 10 so long as the power piston was correctly aligned. This example would also work reasonably with three spring contact pegs 14 spaced at 120° intervals.
- FIG. 3 An alternative arrangement is shown in Figures 3 and 4.
- the section has been taken from the right-hand side of the machine in that the piston 4 is within the alternator 8.
- the spring contact peg and resilient tongue arrangement of Figure 1 has been replaced by a recess 20 in the piston 4 which extends in an axial direction and a spring plug 21.
- Figure 3 where the spring plug 21 is mounted in the alternator 8 it projects into the groove 20.
- the spring plug is shown in greater detail in Figure 4 which shows the spring plug having an enlarged head 22, a tapered portion 23 and a thinner stem 24 which provides the resilience.
- the stem 24 is a heavy press-fit into a fixing bolt 25 which is screwed into the cylinder wall 26.
- Another identical arrangement is provided at the opposite side of the machine. If the piston 4 exceeds its allowed displacement in either direction, the spring plug 21 will contact the ends of the groove 20 and will apply a retarding force.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
- Emergency Lowering Means (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
- Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE602005024695T DE602005024695D1 (en) | 2004-08-06 | 2005-08-04 | LINEAR FREEZING STIRLING MACHINE |
EP05768092A EP1781924B1 (en) | 2004-08-06 | 2005-08-04 | A linear free piston stirling machine |
AT05768092T ATE487867T1 (en) | 2004-08-06 | 2005-08-04 | LINEAR FREE PISTON STIRLING ENGINE |
JP2007524400A JP2008509322A (en) | 2004-08-06 | 2005-08-04 | Linear free piston Stirling device |
US11/659,529 US7584612B2 (en) | 2004-08-06 | 2005-08-04 | Linear free piston Stirling machine |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0417610.3 | 2004-08-06 | ||
GBGB0417610.3A GB0417610D0 (en) | 2004-08-06 | 2004-08-06 | A linear free piston stirling machine |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006013380A1 true WO2006013380A1 (en) | 2006-02-09 |
Family
ID=32982682
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2005/003075 WO2006013380A1 (en) | 2004-08-06 | 2005-08-04 | A linear free piston stirling machine |
Country Status (7)
Country | Link |
---|---|
US (1) | US7584612B2 (en) |
EP (1) | EP1781924B1 (en) |
JP (1) | JP2008509322A (en) |
AT (1) | ATE487867T1 (en) |
DE (1) | DE602005024695D1 (en) |
GB (1) | GB0417610D0 (en) |
WO (1) | WO2006013380A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5717746B2 (en) * | 2009-10-28 | 2015-05-13 | グローバル・クーリング・インクGlobalCooling, Inc. | A free-piston Stirling engine that has a reciprocating piston connected to a rotary electromagnetic transducer that rotates and vibrates, and is light and free of lubrication. |
CN111608819B (en) * | 2019-02-25 | 2022-07-22 | 中国科学院理化技术研究所 | Stirling heat engine |
US11209192B2 (en) * | 2019-07-29 | 2021-12-28 | Cryo Tech Ltd. | Cryogenic Stirling refrigerator with a pneumatic expander |
CN111691925B (en) * | 2020-06-24 | 2021-11-09 | 张谭伟 | Air engine |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3782859A (en) * | 1971-12-07 | 1974-01-01 | M Schuman | Free piston apparatus |
US4397155A (en) * | 1980-06-25 | 1983-08-09 | National Research Development Corporation | Stirling cycle machines |
GB2114673A (en) * | 1982-02-12 | 1983-08-24 | Nat Res Dev | Improvements in or relating to free piston heat engines |
JPS58210379A (en) * | 1982-05-29 | 1983-12-07 | Matsushita Electric Ind Co Ltd | Reciprocating compressor driven by heat engine |
GB2136087A (en) | 1983-03-08 | 1984-09-12 | Atomic Energy Authority Uk | Annular Spring |
JPH0447150A (en) | 1990-06-14 | 1992-02-17 | Mitsubishi Electric Corp | Free-piston stirling engine |
DE19538422A1 (en) | 1995-10-16 | 1997-04-17 | Krauch Helmut Prof Dr | Controlling output of Stirling-type thermal engine |
US5693991A (en) * | 1996-02-09 | 1997-12-02 | Medis El Ltd. | Synchronous twin reciprocating piston apparatus |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4475346A (en) * | 1982-12-06 | 1984-10-09 | Helix Technology Corporation | Refrigeration system with linear motor trimming of displacer movement |
US5593991A (en) * | 1993-07-16 | 1997-01-14 | Adams; Jerry L. | Imidazole compounds, use and process of making |
US6050092A (en) * | 1998-08-28 | 2000-04-18 | Stirling Technology Company | Stirling cycle generator control system and method for regulating displacement amplitude of moving members |
US6199381B1 (en) | 1999-09-02 | 2001-03-13 | Sunpower, Inc. | DC centering of free piston machine |
JP3866974B2 (en) | 2001-06-19 | 2007-01-10 | シャープ株式会社 | Stirling agency |
JP3865679B2 (en) | 2002-01-08 | 2007-01-10 | シャープ株式会社 | Stirling refrigerator |
WO2003056257A1 (en) | 2001-12-26 | 2003-07-10 | Sharp Kabushiki Kaisha | Stirling engine |
GB0428057D0 (en) | 2004-12-22 | 2005-01-26 | Microgen Energy Ltd | A linear free piston stirling machine |
-
2004
- 2004-08-06 GB GBGB0417610.3A patent/GB0417610D0/en not_active Ceased
-
2005
- 2005-08-04 EP EP05768092A patent/EP1781924B1/en not_active Not-in-force
- 2005-08-04 AT AT05768092T patent/ATE487867T1/en not_active IP Right Cessation
- 2005-08-04 US US11/659,529 patent/US7584612B2/en not_active Expired - Fee Related
- 2005-08-04 WO PCT/GB2005/003075 patent/WO2006013380A1/en active Application Filing
- 2005-08-04 DE DE602005024695T patent/DE602005024695D1/en active Active
- 2005-08-04 JP JP2007524400A patent/JP2008509322A/en active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3782859A (en) * | 1971-12-07 | 1974-01-01 | M Schuman | Free piston apparatus |
US4397155A (en) * | 1980-06-25 | 1983-08-09 | National Research Development Corporation | Stirling cycle machines |
GB2114673A (en) * | 1982-02-12 | 1983-08-24 | Nat Res Dev | Improvements in or relating to free piston heat engines |
JPS58210379A (en) * | 1982-05-29 | 1983-12-07 | Matsushita Electric Ind Co Ltd | Reciprocating compressor driven by heat engine |
GB2136087A (en) | 1983-03-08 | 1984-09-12 | Atomic Energy Authority Uk | Annular Spring |
JPH0447150A (en) | 1990-06-14 | 1992-02-17 | Mitsubishi Electric Corp | Free-piston stirling engine |
DE19538422A1 (en) | 1995-10-16 | 1997-04-17 | Krauch Helmut Prof Dr | Controlling output of Stirling-type thermal engine |
US5693991A (en) * | 1996-02-09 | 1997-12-02 | Medis El Ltd. | Synchronous twin reciprocating piston apparatus |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 008, no. 057 (M - 283) 15 March 1984 (1984-03-15) * |
Also Published As
Publication number | Publication date |
---|---|
ATE487867T1 (en) | 2010-11-15 |
US7584612B2 (en) | 2009-09-08 |
JP2008509322A (en) | 2008-03-27 |
EP1781924A1 (en) | 2007-05-09 |
DE602005024695D1 (en) | 2010-12-23 |
EP1781924B1 (en) | 2010-11-10 |
US20080047265A1 (en) | 2008-02-28 |
GB0417610D0 (en) | 2004-09-08 |
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