A monolithic heater body may include a combustor body, a hot-side heat exchanger body, and an eductor body. The combustor body may define a combustion chamber and a conditioning conduit circumferentially surrounding the combustion chamber. The conditioning conduit may fluidly communicate with the combustion chamber at a distal portion of the combustion chamber. The hot-side heat exchanger body may define a hot-side heat exchanger that includes a heating fluid pathway fluidly communicating with a proximal portion of the combustion chamber. The eductor body may define an eduction pathway fluidly communicating with a downstream portion of the heating fluid pathway and a proximal portion of the conditioning conduit.

A monolithic heat exchanger body includes a plurality of heating walls and a plurality of combustion fins. The plurality of heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis. Adjacent portions of the plurality of heating walls respectively define a corresponding plurality of heating fluid pathways therebetween. The plurality of combustion fins are circumferentially spaced about a perimeter of an inlet plenum. The inlet plenum includes or fluidly communicates with a combustion chamber. The plurality of heating fluid pathways fluidly communicate with the inlet plenum. The plurality of combustion fins occupy a radially or concentrically inward portion of the monolithic heat exchanger body. The plurality of heating fluid pathways have a heat transfer relationship with a heat sink disposed about a radially or concentrically outward portion of the monolithic heat exchanger body. A plurality of conduction breaks disposed radially or concentrically outward relative to the plurality of combustion fins at least partially inhibit heat conduction from the plurality of combustion fins to the plurality of heating walls.

A monolithic heat exchanger body includes a plurality of heating walls and a plurality of combustion fins. The plurality of heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis. Adjacent portions of the plurality of heating walls respectively define a corresponding plurality of heating fluid pathways therebetween. The plurality of combustion fins are circumferentially spaced about a perimeter of an inlet plenum. The inlet plenum includes or fluidly communicates with a combustion chamber. The plurality of heating fluid pathways fluidly communicate with the inlet plenum. The plurality of combustion fins occupy a radially or concentrically inward portion of the monolithic heat exchanger body. The plurality of heating fluid pathways have a heat transfer relationship with a heat sink disposed about a radially or concentrically outward portion of the monolithic heat exchanger body. A plurality of conduction breaks disposed radially or concentrically outward relative to the plurality of combustion fins at least partially inhibit heat conduction from the plurality of combustion fins to the plurality of heating walls.

A method for limiting the amplitude of reciprocation of a piston reciprocating in a cylinder of a free-piston Stirling engine. The method is the combination of both at least partially covering the heat rejecter cylinder port by the piston sidewall during a peak part of the inward reciprocation of the piston and at least partially covering the heat rejecter cylinder port by the displacer sidewall during a peak part of the outward reciprocation of the displacer. The piston and the displacer, at times during their reciprocation, fully cover the effective heat rejecter cylinder port when the piston amplitude of reciprocation is large and approaches the physical limit of the amplitude of reciprocation in order to avoid internal collisions by a reciprocating component.

A method for limiting the amplitude of reciprocation of a piston reciprocating in a cylinder of a free-piston Stirling engine. The method is the combination of both at least partially covering the heat rejecter cylinder port by the piston sidewall during a peak part of the inward reciprocation of the piston and at least partially covering the heat rejecter cylinder port by the displacer sidewall during a peak part of the outward reciprocation of the displacer. The piston and the displacer, at times during their reciprocation, fully cover the effective heat rejecter cylinder port when the piston amplitude of reciprocation is large and approaches the physical limit of the amplitude of reciprocation in order to avoid internal collisions by a reciprocating component.

Systems and methods are disclosed to recover waste heat from an engine fluid with a heat exchanger subsystem that includes a heat exchanger. The heat exchanger subsystem is thermally coupled to a working fluid and the engine fluid, so the waste heat from the engine fluid is transferred to the working fluid. The engine fluid is bypassed from the heat exchanger in response to a heat exchanger bypass condition.

Systems and methods are disclosed to recover waste heat from an engine fluid with a heat exchanger subsystem that includes a heat exchanger. The heat exchanger subsystem is thermally coupled to a working fluid and the engine fluid, so the waste heat from the engine fluid is transferred to the working fluid. The engine fluid is bypassed from the heat exchanger in response to a heat exchanger bypass condition.

The present invention discloses an automatic cooling system based on stirling engine for combustion engine. The system is configured to utilize thermal energy from the temperature difference between the engine and a radiator to feed the stirling engine. The stirling engine drives a coolant pump to circulate a coolant between the engine and the radiator. If the temperature difference between the combustion engine and the radiator is high, the stirling engine automatically drives the coolant pump and circulates the coolant at high speed. If the temperature difference between the combustion engine and the radiator is low, the stirling engine automatically drives the coolant pump and circulates the coolant at low speed, until the temperature difference between the engine and radiator within a threshold point. Therefore, there is no need for a thermostat and a water pump coupled with the engine.

The present invention discloses an automatic cooling system based on stirling engine for combustion engine. The system is configured to utilize thermal energy from the temperature difference between the engine and a radiator to feed the stirling engine. The stirling engine drives a coolant pump to circulate a coolant between the engine and the radiator. If the temperature difference between the combustion engine and the radiator is high, the stirling engine automatically drives the coolant pump and circulates the coolant at high speed. If the temperature difference between the combustion engine and the radiator is low, the stirling engine automatically drives the coolant pump and circulates the coolant at low speed, until the temperature difference between the engine and radiator within a threshold point. Therefore, there is no need for a thermostat and a water pump coupled with the engine.

A method for limiting the amplitude of reciprocation of a piston reciprocating in a cylinder of a free-piston Stirling engine. The method is the combination of both at least partially covering the heat rejecter cylinder port by the piston sidewall during a peak part of the inward reciprocation of the piston and at least partially covering the heat rejecter cylinder port by the displacer sidewall during a peak part of the outward reciprocation of the displacer. The piston and the displacer, at times during their reciprocation, fully cover the effective heat rejecter cylinder port when the piston amplitude of reciprocation is large and approaches the physical limit of the amplitude of reciprocation in order to avoid internal collisions by a reciprocating component.