Power plants – Motor operated by expansion and/or contraction of a unit of... – Unit of mass is a gas which is heated or cooled in one of a...
Reexamination Certificate
2000-03-10
2001-12-25
Nguyen, Hoang (Department: 3748)
Power plants
Motor operated by expansion and/or contraction of a unit of...
Unit of mass is a gas which is heated or cooled in one of a...
C060S522000, C060S524000, C060S526000, C060S515000
Reexamination Certificate
active
06332319
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a heat engine.
BACKGROUND OF THE INVENTION
The heat engine is an alternate engine to the internal combustion engine. Various designs for heat engines have been developed in the past. Despite its potential for greater thermodynamic efficiency compared to internal combustion engines, heat engines have been used in only limited applications in the past due to several factors including the complexity of the designs, the weight of the engine per unit of horse power output as well as the difficulty in starting a heat engine.
SUMMARY OF THE INVENTION
In accordance with the instant invention, an improved design for a heat engine is disclosed. In one embodiment, the heat engine is made from lightweight sheet metal. By using a plurality of cylindrical containers, one nested inside the other for the displacer, the combustion and cooling chambers as well as to create an air flow path between the heating and cooling chambers, a rugged durable lightweight construction is achieved.
In another embodiment, the heat engine utilizes a power piston which is biased to a first position. By biasing the piston, several advantages are obtained. First, the heat engine may be self starting provided the power piston is biased so as to be initially positioned in the cooling chamber. A further advantage is that by using an electrical means (eg. a solenoid, an electromagnet or the like) to move the displacer, preferably in response to the position of the power piston, a complicated mechanical linkage between the power piston and the displacer is not required thus simplifying the design. Further, by using an electrical linkage, the phase angle between the displacer and the power piston may be adjusted.
The heat engine of the instant invention may be combined with a fuel source (eg. butane), a linear generator and an electrically operated light emitting means to create a flashlight or other portable light source. It will be appreciated that due to the simplicity of the design of the instant invention, the heat engine as well as the linear generator are each adapted to be scaled up or down so as to produce greater or lessor amounts of power. Accordingly, in another embodiment, the heat engine together with a linear generator and a fuel source may be used as a generator. It will further be appreciated that by connecting a linear generator to a source of electricity (eg. standard electrical outlet) the electricity from a power grid may be used to run the linear generator as a motor whereby the power piston effectively drives the displacer. In such a case, the heat engine may be used as a refrigerator or a cryogenic cooler. In such an embodiment, the heating and cooling chambers of the heat engine are effectively reversed and no combustion chamber is required.
In accordance with one aspect of the instant invention, there is provided a heat engine comprising inner and outer spaced apart longitudinally extending walls, each wall having an inner surface and an outer surface, the inner wall surrounding a cavity, each of the inner and outer wall having longitudinally spaced apart first and second ends, the first end is at a different temperature than the second end when the heat engine is in use, the first and second ends in fluid flow communication via a passageway, the first and second ends and the passageway defining a sealed region within which a working fluid is circulated when the heat engine is in use; a displacer movably mounted in the cavity between the first and second ends for movement between a first position and a second position; a piston movably mounted in the second end for movement between a first position and a second position; and, a heat exchanger mounted on a portion of the outer surface of the outer wall, the heat exchanger comprising at least one cooling fin extending around the outer wall and having first and second opposed sides and constructed to permit a cooling fluid to flow there through.
In one embodiment, the at least one cooling fin is configured and arranged to permit cooling fluid to flow from the first opposed side to the second opposed side and to direct cooling fluid from the second opposed side to the first opposed side. Preferably, the at least one cooling fin has at least one main directing member which is configured and arranged to cause a portion of the cooling fluid to pass at least twice through the main directing member as the cooling fluid flows through the cooling fin. Alternately, the at least one cooling fin has at least one main directing member, the main directing member having a first side, a second side and is configured and arranged to cause a portion of the cooling fluid to flow unidirectionally from the first side of a main directing member to the second side of the main directing member as the fluid flows through the cooling fin.
In another embodiment, the at least one cooling fin has main directing members and fluid flow passages through which the fluid may pass through the cooling fin, the main directing members are configured and arranged to cause a portion of the cooling fluid which has passed through the cooling fin from the first opposed side to the second opposed side to then pass from the second opposed side to the first opposed side.
In another embodiment, the at least one cooling fin is configured and arranged to cause at least a portion of the cooling fluid to swirl around the outer surface of the outer wall. Preferably, the at least one cooling fin has at least one main directing member which is configured and arranged to cause a portion of the cooling fluid to pass at least twice through the main directing member as the cooling fluid flows through the cooling fin. Alternately, the at least one cooling fin has at least one main directing member, the main directing member having a first side, a second side and is configured and arranged to cause a portion of the cooling fluid to flow unidirectionally from the first side of a main directing member to the second side of the main directing member as the fluid flows through the cooling fin.
In one embodiment, the at least one cooling fin comprises a plurality of longitudinally spaced apart cooling fins. and/or a helical cooling fin.
In another embodiment, at least some of the cooling fins are constructed from metal and are prepared by stamping.
In another embodiment, at least some of the cooling fins have a deformable collar for lockingly engaging the outer surface of the outer wall. Preferably, the fins are mechanically affixed to the outer wall by a pressure which is exerted between the fins and the outer wall which is sufficient to ensure that the rate of heat transfer between the outer wall and the fins is maintained over the normal operating temperature of the outer wall.
In another embodiment, the second end of the inner cavity is cooler than the first end and the heat exchanger is mounted on the outer wall at a position adjacent the second end of the cavity.
In another embodiment, the at least one cooling fin has an inner hub adjacent the outer wall and an annular body portion extending outwardly from the inner hub, and openings and main directing members are provided in the annular body portion.
In another embodiment, the at least one cooling fin has an inner hub adjacent the outer wall and a plurality of blades extending outwardly from the inner hub, the blades defining passages through which the cooling fluid flows.
In another embodiment, the at least one cooling fin comprises a helical member mounted on the outer wall.
In accordance with another aspect of the instant invention, there is provided a heat engine comprising an outer member comprising an outer longitudinally extending wall having an outer surface and first and second longitudinally spaced apart ends, the outer wall surrounding an outer cavity; an inner member spaced from the outer member and comprising an inner longitudinally extending wall surrounding an inner cavity having first and second longitudinally spaced apart ends, the inner longitudinally extending wall having first and se
Bereskin & Parr
Fantom Technologies Inc.
Mendes da Costa Philip C.
Nguyen Hoang
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