Stirling Thermal Motors, Inc.

Stm, Inc.

Other

U.S. Philips Corporation

Volvo Flygmotor Ab

Stm Power, Inc.

Benjamin Ziph

Roelf J Meijer

William H Houtman

Lennart N Johansson

Ted M Godett

Christopher Domanski

Thomas K Rose

Christopher E Domanski

Nicholas R Marchionna

Robert P Verhey

Stephen C Matthews

Robert J Brown

Scott Strodtman

Roelf L Meijer

A working gas pressure equalization system for a multiple-cylinder, double-acting hot gas engine such as a Stirling engine of the type having a plurality of pistons reciprocatable within the cylinders defining a plurality of generally isolated cycle volumes of a working gas separated by the pistons. The equalization system incorporates passages through the piston connecting rods which connect between a space between piston rings and an equalization volume defined between a pair of sliding rod seals. This volume is defined by portions from each of the cylinders and is connected with individual cycle volumes by a valve, such as a one-way check valve. When a pressure is experienced in one of the cycle volumes different from the minimum pressure maintained and the equalization volume, minute gas leakage across the piston rings enables pressure among the volumes to be equalized.

Hydrogen equalization system for double-acting stirling engine

A heater assembly for a heat engine designed to utilize solar energy and heat produced by combustion of a fuel such as natural gas. A receiver housing allows concentrated solar energy to be directed through a receiver aperture into a receiver chamber. Inner and outer arrays of heater tubes within the receiver chamber absorb the solar energy and transfer heat to working fluid in the heater tubes. A burner within the housing produces combustion gases which circulate past the heater tubes and transfer heat to the working fluid. The heater tubes form an opaque surface to solar energy and have uniform gaps which allow heated fluid to be passed between adjacent heater tubes. A precise three-dimensional mathematical description for the centerlines of the heater tubes which maintains uniform gaps between adjacent heater tubes is disclosed.

Heat engine heater assembly

A piston assembly for a double-acting engine such as a double-acting Stirling engine. A pair of sealing rings located on opposite sides of a sealing washer are positioned between a base section and a dome section of a piston head. These sealing rings are alternatively urged into sealing engagement with the cylinder bore as the piston reciprocates. A single sealing ring design is also disclosed in which the sealing ring is urged into constant sealing engagement by positive pressure accumulated with an interior cavity in the piston head.

Piston assembly for stirling engine

A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

Speed and power control of an engine by modulation of the load torque

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 heat pipe system particularly adapted for use with finned evaporators. In accordance with this invention, a separate liquid working fluid return conduit is provided which communicates with a liquid working fluid distribution means for distributing working fluid uniformly to all of the evaporator fins. Means are also provided in accordance with this invention for storing excess liquid working fluid either as a column of liquid within the liquid return pipe which is developed by a flow restrictor, or by selecting a distribution wick from a material having low capillary pressure which enables it to become saturated with liquid working fluid.

Heat pipe working liquid distribution system

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

A corrosion resistant heat pipe construction which prevents the formation of corrosive oxides of sodium which may result when a sodium heat transport medium combines with oxygen within the heat pipe. In accordance with this invention, formation of such corrosive compounds is inhibited through the introduction of zirconium in the form of a fine thread woven into the heat pipe wick. When the wick is installed within the heat pipe, the zirconium will react with oxygen to form a relatively non-corrosive zirconium oxide. By introducing the zirconium thread into the wick material matrix, the fabrication of the heat pipe is carried out in accordance with present techniques, without requiring the addition of other components or operations.

Corrosion resistant heat pipe

An improved heat pipe comprising a duct having disposed at opposite ends thereof an evaporator with wick-lined hollow fins in the form of extended corrugations thereon, and operable to supply heat to the evaporator comprised of a gas combustor having an internal volume for containing the evaporator and combustion air for supply to a combustion chamber located therein; a wick capable of transporting liquid by capillary action lining substantially all internal surfaces of said heat pipe; an external heat sink operable to remove heat from the condenser; and a heat transport medium contained by said heat pipe. The evaporator is further comprised of a coarse porous material lining and completely filling the spaces within the hollow fins open to the evaporator for increased structural stiffness and ease of fabrication; and a porous mass completely filling the evaporator for increased compressive strength. The coarse porous material and the porous mass are sufficiently porous to allow vapor to flow through each with a minimum of obstruction.

Heat pipe

Improved lubricant control assemblies 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 scraper fitting closely onto a piston rod and yieldably mounted within the bore between cylinder and crankcase through which the piston rod extends. The yieldable mounting is by means of a compliant housing. The compliant housing allows the scraper to be displaced radially and thereby follow limited radial displacement of the piston rod while maintaining substantially full effectiveness of the scraper's action on the reciprocating piston rod. The scraper is urged into forceful contact around the piston rod by means of a crown spring which is supported on a tubular part which attaches to the compliant housing. The compliant housing comprises an outer ring portion which is threaded into the bore to mount the assembly on the engine and an inner ring portion which attaches to the tubular part. One or more intermediate ring portions may be included in the compliant housing. Each ring portion joins to its immediate ring portion(s) at only one axial end with the points of joining alternating axially from each ring to the next. A disclosed embodiment for the compliant housing comprises a one piece nylon part.

A heat exchanger stack apparatus for use on a remotely heated Stirling engine having a variable swashplate drive mechanism, which comprises rigidly combining a regenerator, a flexible heat exchanger, a short, rigid hot connecting duct and a cylinder. A heat exchanger stack apparatus for each cylinder of the engine is mounted on a drive mechanism housing with the regenerator adjacent to a cooler located within the drive mechanism housing. The cooler, regenerator and flexible heat exchanger are axially aligned providing a linear flowpath for the engine working fluid. Bellows and flexible tubes connected to the flexible heat exchanger provide axial and transverse flexibility to reduce thermal stresses within the heat exchanger stack apparatus.

Growing community of inventors

Ann Arbor, MI, United States of America

Benjamin Ziph