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
2000-05-16
2001-08-07
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...
C060S523000, C060S524000, C060S515000
Reexamination Certificate
active
06269640
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) and preferably a magnetic drive member (eg. an electromagnet) 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 an apparatus comprising:
(a) a heat engine comprising:
(i) a container defining a sealed region within which a working fluid is circulated when the heat engine is in use, the sealed region having a heating chamber and a cooling chamber, the heating and cooling chambers being in fluid flow communication via a working fluid passageway;
(ii) a variable heat source thermally connected to the heating chamber whereby the variable heat source provides variable heat levels to the working fluid;
(iii) a displacer movably mounted in the sealed region between a first position and a second position to define a displacer cycle profile;
(iv) a piston movably mounted in the sealed region between a first position and a second position to define a piston cycle profile;
(b) an power output member drivenly connected to the heat engine and having an output for supplying work; and,
(c) a feedback member responsive to power demand from the power output member to modulate the amount of heat provided by the heat source to the working fluid.
In one embodiment, the power output member comprises an electric generator drivenly connected to the heat engine and having an output for supplying current to a load. Alternately the power output member may be a linear to rotary generator or other mechanical means for withdrawing power from a heat engine. Any such means known in the art may be used.
In another embodiment, the feedback member includes a thermal sensor thermally connected to a thermal source whose temperature changes as the power demand from the power output member varies.
In another embodiment, the thermal sensor is reconfigurable on heating and is mechanically connected to the variable heat source to adjust the amount of heat provided by the variable heat source in response to a reconfiguration of the thermal sensor.
In another embodiment, the thermal sensor comprises a driving member which is reconfigurable on heating and is drivingly connected to the variable heat source whereby the thermal sensor adjusts the amount of heat provided by the variable heat source.
In another embodiment, the thermal source is the heat source whereby the temperature of the heat source is used to sense the power demanded of the power output member.
In another embodiment, the variable heat source comprises a combustion chamber and a variable fuel flow valve associated thereto, the variable fuel flow valve is adjustable to a plurality of positions to provide varying flow rates of fuel to the combustion chamber, the feedback member is drivingly connected to the variable fuel flow valve and includes a thermal sensor thermally connected to the combustion chamber whereby the temperature of the combustion chamber varies inversely to the power drawn from the power output member, the thermal sensor senses the temperature of the combustion chamber and the feedback member adjusts the flow rate of fuel supplied to the combustion chamber to maintain the temperature of the combustion chamber within a preset range.
In another embodiment, the variable heat source has a control member to adjust the temperature of the variable heat source and the feedback member is drivingly connected to the control member and the thermal source is the heat source whereby the temperature of the heat source is used to sense the power demanded from the power output member.
In another embodiment, the power output member comprises an electric generator drivenly connected to the heat engine and having an output for supplying current to a load, the feedback member comprises a circuit including a resistor electrically connected to the circuit to draw current proportional to the power demand drawn from the electric generator and the thermal source is the resistor whereby the temperature of the resistor is used to sense the power demand from the output.
In another embodiment, the variable heat source comprises a combustion chamber and a variable fuel flow valve associated thereto, the variable fuel flow valve is adjustable to a plurality of positions to provide varying flow rates of fuel to the combustion chamber, the feedback member is drivingly connected to the variable fuel flow valve and comprises a circuit including a resistor electrically connected to the circuit to draw current proportional to the power demand drawn from the output, and a thermal sensor thermally connected to the resistor whereby the thermal sensor indirectly senses the power demand of a load applied to the output and the feedback member adjusts the flow rate of fuel supplied to the combustion chamber to maintain the temperature of the combustion chamber within a preset range.
In another embodiment, the variable heat source has a control member to adjust the temperature of the variable heat source and the feedback member is drivingly connected to the control member and comprises a circuit including a sensor portion which provides a signal to the control member based on the power demand drawn from the output.
In another embodiment, the apparatus further comprises a thermal sensor thermally connected to the sensor portion and the sensor portion changes temperature based on the power dema
Bereskin & Parr
Fantom Technologies Inc.
Mendes da Costa Philip C.
Nguyen Hoang
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