Abstract: A monolithic engine assembly may include an engine body that includes a regenerator body. The engine body and the regenerator body may respectively define at least a portion of a monolithic body, or the engine body may define at least a portion of a first monolithic body-segment and the regenerator body may define at least a portion of a second monolithic body-segment operably coupled or operably couplable to the first monolithic body-segment. The regenerator body may include a regenerator conduit, and a plurality of fin arrays adjacently disposed within the regenerator conduit and respectively supported by the regenerator conduit in spaced relation to one another. The spaced relation of the plurality of fin arrays may define a gap longitudinally separating adjacent ones of the plurality of fin arrays.

Abstract: A nested segment assembly and a method of additively manufacturing the same are provided. In one example aspect, the nested segment assembly includes a first component segment and a segment component segment positioned adjacent the first component segment. The first component segment has an end face and a tongue projecting outwardly from the end face. The second component segment defines a groove. The groove is defined at an end face of the second component segment that is adjacent the end face of the first component segment. The first component segment and the second component segment are additively printed such that at least a portion of the tongue of the first component segment is nested within the groove defined by the second component segment. Segmented components having a tesla valve formed therebetween are also provided.

Abstract: A shrouded impeller and a method of additively manufacturing the same are provided. In one example aspect, the shrouded impeller includes a hub and a shroud spaced from the hub. The shrouded impeller also includes a plurality of vanes extending between and connecting the hub and the shroud. The vanes are spaced circumferentially apart from one another. Flow passages are defined between adjacent vanes. In some implementations, the shrouded impeller is additively manufactured. During printing, one or more support structures are formed within and fill a portion of one or more of the flow passages to support the unsupported walls of the shrouded impeller, e.g., the shroud. Further, the support structures are removable from the shrouded impeller, e.g., after the shrouded impeller has been printed.

Abstract: A constant density heat exchanger is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid held at constant density within the chamber by the first and second control devices.

Abstract: 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.

Abstract: A system including a closed cycle engine having a piston body defining a hot side and a cold side and having a piston assembly movable within the piston body. An electric machine is operatively coupled with the piston assembly. A control system includes one or more sensors operable to detect a piston movement characteristic of the piston assembly movable within the piston body. A controller is communicatively coupled with the one or more sensors and a controllable device. The controller is configured to determine a control command based at least in part on data received from the one or more sensors. The control command is selected based at least in part to cause the electric machine operatively coupled with the piston assembly to generate a preselected electrical power output. The controller provides the determined control command to the controllable device. The controllable device is operable to control an input to an engine working fluid disposed within the piston body.

Abstract: A monolithic heat exchanger body for inputting heat to a closed-cycle engine may include a plurality of heating walls and heat sink, such as a plurality of heat transfer regions. The plurality of heating walls may be configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the plurality of heating walls may respectively define a corresponding plurality of heating fluid pathways therebetween, for example, fluidly communicating with the inlet plenum. At least a portion of the heat sink may be disposed about at least a portion of the monolithic heat exchanger body. The heat sink may include a plurality of working-fluid bodies, for example, including a plurality of working-fluid pathways that have a heat transfer relationship with the plurality of heating fluid pathways.

Abstract: Systems and methods for converting energy are provided. In one aspect, the system includes a closed cycle engine having a piston body and a piston assembly movable within the piston body. An electric machine is operatively coupled with the piston assembly and operable to generate electrical power. An electrical device is in communication with the electric machine. The system includes a control system having sensors, a controllable device, and a controller. The controller is configured to determine whether a load change on the electric machine is anticipated based at least in part on received data indicative of a load state of the electrical device; in response to whether the load change is anticipated, determine a control command for adjusting an output of at least one of the engine and the electric machine; and cause the controllable device to adjust the output based at least in part on the control command.

Abstract: A monolithic heater body includes a combustor body and an eductor body. The combustor body has an annulus with an outward annular wall and an inward annular wall. The annulus defines a conditioning conduit between the outward annular wall and the inward annular wall, and a combustion chamber circumferentially surrounded by the inward annular wall. A distal portion of the conditioning conduit fluidly communicates with a distal portion of the combustion chamber. The eductor body defines a plurality of eductive pathway couplets circumferentially spaced about a perimeter of the annulus. Respective ones of the eductive pathway couplets have a motive pathway and an eduction pathway respectively oriented oblique to the annulus and fluidly communicating with the conditioning conduit. Respective ones of the plurality of motive pathways are configured to provide a jet of intake air from a corresponding plurality of intake air pathways to the conditioning conduit.

Abstract: 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.

Abstract: An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly, that includes a first heater body and a first engine body. The first heater body may define a first portion of a first monolithic body or at least a portion of a first monolithic body-segment. The first engine body may define a second portion of the first monolithic body or at least a portion of a second monolithic body-segment operably coupled or operably couplable to the first heater body. The engine assembly may include a second heater body and/or a second engine body. The second heater body may define a portion of a second monolithic body or a third monolithic body-segment. The second engine body may define a portion of the second monolithic body or a fourth monolithic body-segment operably coupled or operably couplable to the second heater body and/or the first engine body.

Abstract: A system including a closed cycle engine having a piston body defining a hot side and a cold side and having a piston assembly movable within the piston body. An electric machine is operatively coupled with the piston assembly. A control system includes one or more sensors operable to detect a piston movement characteristic of the piston assembly movable within the piston body. A controller is communicatively coupled with the one or more sensors and a controllable device. The controller is configured to determine a control command based at least in part on data received from the one or more sensors. The control command is selected based at least in part to cause the electric machine operatively coupled with the piston assembly to generate a preselected electrical power output. The controller provides the determined control command to the controllable device. The controllable device is operable to control an input to an engine working fluid disposed within the piston body.

Abstract: Systems and methods for converting energy are provided. In one aspect, the system includes a closed cycle engine defining a cold side. The system also includes a bottoming-cycle loop. A pump is operable to move a working fluid along the bottoming-cycle loop. A cold side heat exchanger is positioned along the bottoming-cycle loop in a heat exchange relationship with the cold side of the closed cycle engine. A constant density heat exchanger is positioned along the bottoming-cycle loop downstream of the cold side heat exchanger and upstream of an expansion device. The constant density heat exchanger is operable to hold a volume of the working fluid flowing therethrough at constant density while increasing, via a heat source, the temperature and pressure of the working fluid. The expansion device receives the working fluid at elevated temperature and pressure and extracts thermal energy from the working fluid to produce work.

Abstract: A monolithic combustor body may provide multi-stage combustion. A combustor body may include a combustion chamber body and a plurality of heating walls that include a heat sink. The combustion chamber body may be disposed annularly about a longitudinal axis and defining a combustion chamber. The plurality of heating walls may include heat sink. The plurality of heating walls may occupy a radially or concentrically outward position relative to the combustion chamber and may define a corresponding plurality of combustion-gas pathways fluidly communicating with at least a proximal portion of the combustion chamber.

Abstract: An engine apparatus, in which each piston assembly includes a piston attached to a connection member at a first end and a second end. Each piston of the piston assembly defines a first chamber and a second chamber separated by the piston. The first chamber and the second chamber are each defined at the first end and at the second end. Each first chamber of one piston assembly is fluidly connected to the second chamber at a different piston assembly. At least one first chamber at the first end is fluidly connected to a respective second chamber at the second end. At least one first chamber at the second end is fluidly connected to a respective second chamber at the first end.

Abstract: 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.

Abstract: A monolithic engine assembly may include an engine body that includes a regenerator body. The engine body and the regenerator body may respectively define at least a portion of a monolithic body, or the engine body may define at least a portion of a first monolithic body-segment and the regenerator body may define at least a portion of a second monolithic body-segment operably coupled or operably couplable to the first monolithic body-segment. The regenerator body may include a regenerator conduit, and a plurality of fin arrays adjacently disposed within the regenerator conduit and respectively supported by the regenerator conduit in spaced relation to one another. The spaced relation of the plurality of fin arrays may define a gap longitudinally separating adjacent ones of the plurality of fin arrays.

Abstract: A monolithic heater body includes a combustor body and an eductor body. The combustor body has an annulus with an outward annular wall and an inward annular wall. The annulus defines a conditioning conduit between the outward annular wall and the inward annular wall, and a combustion chamber circumferentially surrounded by the inward annular wall. A distal portion of the conditioning conduit fluidly communicates with a distal portion of the combustion chamber. The eductor body defines a plurality of eductive pathway couplets circumferentially spaced about a perimeter of the annulus. Respective ones of the eductive pathway couplets have a motive pathway and an eduction pathway respectively oriented oblique to the annulus and fluidly communicating with the conditioning conduit. Respective ones of the plurality of motive pathways are configured to provide a jet of intake air from a corresponding plurality of intake air pathways to the conditioning conduit.

Abstract: A constant density heat exchanger and system for energy conversion is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid as the first flow control device and the second flow control device hold the volume of working fluid at constant density within the chamber.

Abstract: 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.