A piston expander and transfer valve for the controlled metering of a pressurised working fluid into an expansion chamber as part of an energy conversion device, and in particular as part of a heat to power conversion device employing a rankine thermodynamic cycle. The piston expander comprising a cylinder having an inlet manifold connected to an aperture in the cylinder's inlet aperture, a piston movable within the cylinder, and a transfer valve assembly movable under the action of changing gas pressure in the main chamber of the piston expander.

Improved multi-section slide valves for internal combustion engines for improved aspiration comprise spaced apart, continuously pressurized, annular oil confinement zones that are defined between select groups of arrays of piston rings. The oil confinement zones are axially spaced along the length of the slide valve and continuously pressured by oil flow passageways communicating between spaced apart arrays of piston rings. During slide valve movement these pressurized oil confinement zones tend to stabilize the slide valve, preventing metal-to-metal contact such as that associated with rocking, tipping, chafing or scrubbing.

Aspiration and multi-section slide valves (24) for internal combustion engines (11). The slide valves (24) include a central, reduced diameter neck (103) connecting separate cylindrical valve sections (104, 105), which have multiple spaced-apart ring groove arrays seating multiple rings. Slide valves (24) utilize spaced apart, continuously pressurized, annular oil confinement zones (101) that are defined between the slide valve exterior and its sleeve (27) between groups of piston ring arrays. The oil zones are axially spaced along the length of the slide valve and continuously pressured by oil flow passageways (106). During slide valve movement these pressurized oil zones tend to stabilize the slide valve (24), preventing metal-to-metal contact such as that associated with rocking, tipping, chafing or scrubbing. When appropriately displaced, the slide valve neck (103) facilitates transverse fluid flow through the slide valve and its confining sleeve between cylinder gas pathways (139, 141).

Improved multi-section slide valves for internal combustion engines for improved aspiration comprise spaced apart, continuously pressurized, annular oil confinement zones that are defined between select groups of arrays of piston rings. The oil confinement zones are axially spaced along the length of the slide valve and continuously pressured by oil flow passageways communicating between spaced apart arrays of piston rings. During slide valve movement these pressurized oil confinement zones tend to stabilize the slide valve, preventing metal-to-metal contact such as that associated with rocking, tipping, chafing or scrubbing.

A split-cycle internal combustion engine (ICE) is provided, comprising a compression cylinder, an expansion cylinder and a crossover valve having a valve cylinder housing inside a shuttle and a combustion chamber structure defining a combustion chamber. The shuttle is configured to perform reciprocating motion inside the valve cylinder synchronously with a compression piston and an expansion piston, thereby alternatingly fluidly coupling and decoupling the combustion chamber with the compression cylinder and with the expansion cylinder, selectively. Sealing rings positioned between the valve cylinder and the shuttle prevent gas leaks between them during the reciprocating motion. In some embodiments, a phase shift between the pistons may be set or varied by a piston phase transmission gear. A bi-directional fluid flow split-cycle internal combustion engine (ICE) is also provided having a first cylinder, a second cylinder, a combustion chamber and a single crossover valve fluidly communicating them.

A split-cycle internal combustion engine (ICE) is provided, comprising a compression cylinder, an expansion cylinder and a crossover valve having a valve cylinder housing inside a shuttle and a combustion chamber structure defining a combustion chamber. The shuttle is configured to perform reciprocating motion inside the valve cylinder synchronously with a compression piston and an expansion piston, thereby alternatingly fluidly coupling and decoupling the combustion chamber with the compression cylinder and with the expansion cylinder, selectively. Sealing rings positioned between the valve cylinder and the shuttle prevent gas leaks between them during the reciprocating motion. In some embodiments, a phase shift between the pistons may be set or varied by a piston phase transmission gear. A bi-directional fluid flow split-cycle internal combustion engine (ICE) is also provided having a first cylinder, a second cylinder, a combustion chamber and a single crossover valve fluidly communicating them. A three-cylinders split-cycle internal combustion engine (ICE) is also provided, having a compression cylinder and a combustion chamber, wherein a single crossover valve alternatingly fluidly couples the combustion chamber to two or more expansion cylinders.