Stirling Thermal Motors, Inc.

U.S. Philips Corporation

Volvo Flygmotor Ab

Roelf J Meijer

Benjamin Ziph

Ted M Godett

Robert P Verhey

Ernst J Meijer

Albertus Peter Michels

Robert J Brown

Kaveh Khalili

Benjamine Ziph

A Stirling engine having a cooler, regenerator and heat exchanger stacked end to end along with a working cylinder position adjacent to the heat transfer stack and connected thereto by several connecting ducts. By using more than one hot connecting duct, their bending stiffness is less as compared with a single duct being the same area as the multiple ducts, allowing thermally induced relative displacement between the elements to occur. The heat exchanger includes a plurality of axially extending tubes spaced apart from one another with a combustor positioned adjacent to the tubes such that the combustion gases flow between the tubes. The tubes are preferably flattened in the direction of the gas flow between them to increase the surface area for heat transfer. Furthermore, wire is coiled around and brazed to the tubes creating a fin for additional heat transfer. A gas flow restrictor is positioned around the heat exchanger tubes over a portion of their lengths in order to produce isothermal heating of the tubes. The combustor has a number of tangential air flow inlets which mixes air with a combustible fuel injected from a nozzle providing a highly turbulent combustion gas flow.

Stirling engine with integrated gas combustor

A cogeneration system is disclosed using a Stirling cycle engine in which the waste heat from the engine and a generator driven by the engine is used for space heating or producing hot water and the generator used to produce electricity. A Stirling engine has numerous advantages over a reciprocating internal combustion engine in cogeneration systems in that the Stirling engine has a longer life, less maintenance cost, less noise and vibration and fewer emissions. With cogeneration, the added energy and fuel required over and above that required to produce a comparable amount of heat allowed to produce the same amount of heat with a conventional furnace or boiler is often less than the amount of electric energy produced from the system thereby resulting in a efficiency greater than 100% in the production of electricity.

Congeneration system with a Stirling engine

Stirling cycle heat engine adapted for use as space heating and/or air conditioners. One embodiment features a Stirling engine prime mover providing a hybrid Stirling machine. Another embodiment utilizes an electric drive motor as a prime mover and a final embodiment is an open drive Stirling thermal engine particularly adapted for automotive belt driven applications. Enhancements in performance are provided by using pressure ratios significantly lower than that ordinarily provided for Stirling cycle engines. Decreases in pressure ratios are provided by intentionally adding dead volume to the cycle and particularly adding this dead volume strategically in the regenerator of the device which has been found to provide performance benefits. The systems according to this invention can be used either as space heaters or air conditioners by appropriately directing heat absorbed and rejected from the heat exchangers of the device to the approrpriate environment.

Stirling cycle heat pump for heating and/or cooling systems

An actuating mechanism for controlling the swashplate angle in a Stirling cycle engine or other engine having parallel reciprocating pistons. The actuation system uses an electric motor for changing swashplate angle. Various embodiments for gear trains for communicating rotation of the electric motor rotor to the swashplate are described. In a first embodiment, a planet gear carrier is driven by the motor and the planet gears simultaneously mesh with two ring gears having a differing number of teeth. Rotation of the carrier creates a high reduction drive for the second ring gear. In accordance with a second embodiment, the ring gear carrier is permitted to freely rotate and a driving sun gear is provided which meshes with the planet gears. In accordance with a third embodiment, the planet gear carrier is driven and the planet gears have two different diameter scrtions which mesh with the two ring gears, thus avoiding the high friction associated with a mismatching of the teeth of the planet gear and ring gears of the first and second embodiments. The fourth embodiment combines the features of the second and third embodiment configurations.

Electric actuator for swashplate

A Stirling engine having multiple cylinders arranged in a square cluster with a gas combustor devices for each cylinder integrated into the engine. The combustor devices include individual combustion chamber tubes for each of the cylinder of the engine. Air is introduced into the chambers in a manner which generates a tangential air flow which mixes with a combustible gas injected from a gas nozzle in the center of the tube which provides a highly turbulent combustible gas flow regime. Combustion gases pass through the Stirling engine heat exchangers to transfer heat to the engine. Exhaust gas heats inlet air through a counterflow heat exchanger. The relatively small size of the combustion chamber tubes enables the components of the combustion chambers to reach an equilibrium temperature repidly and minimizes thermal distortion of the components.

A solar collector particularly for receiving concentrated solar energy from a large parabolic reflector and which forms the evaporator of a heat pipe type heat transfer mechanism. The solar collector is formed from a pair of spherical shell portions which are joined at their perimeters such that they are nearly tangent at their joint. This configuration provides low mechanical stresses on the welded joint, making the structure resistant to creep failure. The inside surfaces of the solar collector are preferably covered with wire screens for the transport of liquid heat pipe working fluid. Various finenesses of mesh can be used. Preferably, a coarse mesh is in intimate contact with the inside surfaces of the collector to act as a transport medium with a finer mesh covering it. These mesh layers can be applied to surfaces of sheet metal blanks through sintering or other processes which are thereafter deformed to the desired shell configurations.

Spherical solar energy collector

A diffuser unit for allowing non-condensing gases collecting within a heat pipe to be eliminated. The embodiments described herein define a cavity for collection of non-condensing gases such as hydrogen. The housings are arranged such that the heat pipe working fluid in vapor form transfers heat to the walls of the housing defining the collection cavity to raise the wall temperature thus increasing its permeability to the non-condensing gas. Accordingly, when the heat pipe is used in applications where non-condensing gases such as hydrogen tend to diffuse into the heat pipe such as when it is directly heated by a hydrocarbon combustion, such non-condensing gases can be readily eliminated. Such diffusion of non-condensing gases occurs without the requirement of providing a conventional 'getter' which uses special material for absorbing or breaking down such non-condensing gases. The diffuser assemblies in accordance with this invention are self-regulating and entirely passive in operation, requiring no external heat inputs or control signals.

Self-heated diffuser assembly for a heat pipe

An improved conduit assembly for coupling a heat pipe evaporator with a Stirling engine heat exchanger. The conduit assembly features a cylindrical main tube section connected to a flared shell joining the heat exchanger of the Stirling engine. The flared shell provides an increasing cross-sectional area which reduces the velocity of vaporized heat pipe working fluid flowing from the heat pipe evaporator to the heat exchanger. Such reduced velocity has been found to minimize entrainment of liquid within the transmitted vapor. The conduit assembly further includes an internal small diameter liquid return duct which provides additional isolation of the liquid and vapor phases of the heat pipe working fluid as a means of further reducing entrainment. Surface tension breakers are provided which communicate the heat exchanger to the inlet end of the liquid return duct to wick away liquid working fluid from the heat exchanger. Contaminant gases within the heat pipe are removed through the use of an externally heated getter and an internal getter within the vapor flow path.

Shell and tube heat pipe condenser

A bearing arrangement particularly useful for supporting the driveshaft of a thermal engine in which the driveshaft is acted upon by a rotating bending load. Since a rotating bending load of such thermal engines generates driveshaft bending deflections which rotate with the driveshaft, the bearings supporting the driveshaft must be capable of accommodating such deflection. Conventional rolling element type bearings can accommodate driveshaft deflection or wobble but have limited operational lifespans. In accordance with this invention, a driveshaft bearing arrangement is provided utilizing plane bearings having spherical surfaces which restrain radial loads while accommodating driveshaft wobble. In one embodiment, the spherical bearing includes a ring member affixed to the driveshaft having a spherical outer surface which closely conforms to a concave bearing surface. In a second embodiment, the driveshaft passes through a ring member having a cylindrical surface interacting with a cylindrical journal surface of the driveshaft to rotatably support the driveshaft. The ring member further has a convex spherical configuration closely conforming to concave spherical surfaces of outer bearing shells which accommodate driveshaft wobble.

Hydrodynamic bearing

Improved lubricant control assemblies are disclosed for reciprocating piston rods of an engine which prevent crankcase lubricant intruding into the cylinders and fluid from the cylinders from escaping into the crankcase. Each assembly comprises a tubular sleeve fitting closely onto a piston rod and yieldably mounted within the bore between cylinder and crankcase through which the piston rod extends. The sleeve is urged into forceful contact around the piston rod by a plurality of disk members which forcefully urge the sleeve in contact around the piston and for controlling lubrication.

Yieldably mounted lubricant control assemblies for piston rods

A combination gas combustor and heat pipe evaporator comprised of elongated cylindrical tubes which overfit one another to create a number of longitudinal gas flow passages. A burner disposed at one end of the device creates hot flue gases which travel initially through an annular passage where heat is conducted to the working fluid of a heat pipe evaporator chamber. The flue gas flow is then reversed in direction to heat the radially outer surface of the tubes making up the heat pipe evaporator, and thereafter flow through passages to warm inlet air to increase combustion efficiency. For both described embodiments, a bellows is provided to accommodate differences in thermal expansion between the tubes making up the heat pipe evaporator. In accordance with a first embodiment, the primary flue gas transport channel has a decreasing annular width with distance from the combuster which results in a lowering Reynolds number for flow which provides a more uniform heat flux along the length of the device. In a second embodiment, the central post is hollow and forms a portion of the heat pipe evaporator. The tubes making up the evaporator chamber may be eccentrically located to provide a narrow bottom gap for longitudinal distribution of liquid phase working fluid and a larger upper gap for escape of vapor phase working fluid.

Combination gas combuster and heat pipe evaporator device

A solar evaporator for use with Stirling engines consisting of a dish shape hollow body having wicking containing a vaporizable liquid heating medium. The body has a pair of separate chambers to reduce the distance that capillary pressure is required to pump the heating medium and the chambers are thermally coupled by the wicking so that the temperatures in the chambers is at all times equalized.

Solar evaporator

An exhaust gas heat exchanger for transferring heat from the exhaust gases of an engine to its liquid coolant, thereby increasing the rate of heating of the coolant. The heat exchanger according to this invention provides a regulated rate of heat transfer despite changes in the temperature of the exhaust gases. The exchanger includes a heat pipe with an evaporator and condenser portion. The evaporator portion is exposed to exhaust gases; thus heating the working fluid in the heat pipe, and the condenser portion is in thermal communication with an engine coolant heater. In order to accommodate a broad range of exhaust gas temperature, the heat exchanger includes means for storing the working fluid such that the quantity of the working fluid transferring heat from the evaporator to the condenser portions can be varied. This system enables substantially all of the working fluid in a liquid phase to be removed from the evaporator (i.e. a complete drying out) when the temperature of the evaporator approaches the upper limit of its operating range.

Exhaust heat recovery system for compartment heating

An external heating system for a heat engine such as a Stirling cycle engine which permits thermal energy to be provided by solar energy or fuel combustion sources. The system employs a complexly shaped heat pipe evaporator section having an enclosed cavity for receiving solar energy and another section forming hollow fins which is exposed to hot combustion gasses. Accordingly, either heat source may be used to evaporate working fluid within the heat pipe which is transferred to the associated heat engine.

Dual source external heating system for a heat pipe

The effectiveness of the lubrication system of a Stirling engine is maintained in a solar dish module for all directions of aiming of the dish by the journal mounting of the engine on the dish module with the center of gravity of the journaled mass eccentric to the journal axis along a particular radial. The engine has a sump which is disposed at a low point of the engine. The center of gravity of the journaled mass lies along a radial from the journal axis which intersects the sump. An additional counterweight is added to achieve the desired eccentricity.

Growing community of inventors

Ann Arbor, MI, United States of America

Roelf J Meijer