Abstract: A linear electrical machine (LEM) comprising a stator mounted in a housing, the housing and stator defining a working cylinder, a central core within the working cylinder and defining a cylindrical stator bore cavity therebetween, a hollow translator axially movable within the working cylinder, extending into the stator bore cavity and forming an exterior magnetic circuit airgap between the translator and the stator, at least one fluid bearing between the central core and the translator providing a bearing gap, wherein the central core is axially fixed in relation to the stator, wherein the at least one fluid bearing provides coaxial location of the translator and central core.

Abstract: A linear electro-mechanical system comprising: a stator including at least first and second stator electronic circuits or groups of circuits; a free piston mover movable in a reciprocating motion relative to the stator, the free piston including: a piston surface; a translator configured so that an electromagnetic force may be applied on the free piston mover by one or more of the stator electronic circuits or groups of circuits; and one or more translator electronic circuits, the system further comprising a switching device for each of the first and second stator electronic circuits or groups of circuits such that the current in each of the first and second stator electronic circuits or groups of circuits is independently controllable, and wherein at least one of the translator electronic circuits is configured to receive power from at least one of the independently controlled stator electronic circuits or groups of circuits during at least part of the stroke of the free piston mover.

Abstract: An actuator comprising a linear electrical machine (LEM) having a stator with a stator bore and a translator axially movable within the stator bore and defining a magnetic circuit airgap therebetween, at least one fluid bearing journal formed on the translator, at least one fluid bearing providing a bearing gap adjacent the translator to allow the translator to move axially within the stator bore, a preload chamber for applying a preload force to the translator, wherein the preload chamber is defined by a side wall, a first end wall and a second end wall at least part of which is movable with the translator, and wherein the bearing gap and the magnetic circuit airgap are coaxial.

Abstract: Adaptive control of a Free Piston Mover (1, 19), wherein a Control Parameter Set (COPS?) for closed loop control of a Target Control Variable (CVt) is adapted using a Future-Stroke Controller (20) to respond to Input Demand (21) signals whilst ensuring a sufficient current control margin and compensating for system changes over time. The Control Parameter Set (COPS?) is transmitted to an In-Stroke Controller (23) in advance of the start of a stroke to be controlled, and the In-Stroke Controller (23) transmits a Current Demand (Qt) to a Current Controller (25) of the Free Piston Mover (119).

Abstract: A linear electrical machine (LEM) comprising: at least onestator mounted in a housing, the housing and stator defining a working cylinder; a two-section central core within the working cylinder, wherein the two sections of the core are co-axial, separate and cantilever mounted within the working cylinder; a cylindrical stator bore cavity between the working cylinder and the two central core sections; and one or more hollow translators, each translator being axially movable within the stator bore cavity, such that each section of the central core is traversed by part of the one or more translators, thereby forming an exterior magnetic circuit airgap between the respective translator and stator.

Abstract: An actuator comprising a linear electrical machine (LEM) having a stator with a stator bore and a translator axially movable within the stator bore and defining a magnetic circuit airgap therebetween, at least one fluid bearing journal formed on the translator, at least one fluid bearing providing a bearing gap adjacent the translator to allow the translator to move axially within the stator bore, a preload chamber for applying a preload force to the translator, wherein the preload chamber is defined by a side wall, a first end wall and a second end wall at least part of which is movable with the translator, and wherein the bearing gap and the magnetic circuit airgap are coaxial.

Abstract: A linear electrical machine (LEM) comprising a stator mounted in a housing, the housing and stator defining a working cylinder, a central core within the working cylinder and defining a cylindrical stator bore cavity therebetween, a hollow translator axially movable within the working cylinder, extending into the stator bore cavity and forming an exterior magnetic circuit airgap between the translator and the stator, at least one fluid bearing between the central core and the translator providing a bearing gap, wherein the central core is axially fixed in relation to the stator, wherein the at least one fluid bearing provides coaxial location of the translator and central core.

Abstract: A linear electrical machine comprising a movable piston, an axially segmented cylinder having least one magnetically permeable segment and a bore configured to allow the piston to move within the cylinder, a cylinder housing having a bore for receiving the segmented cylinder, and means for securing the segmented cylinder in place within the cylinder housing. This arrangement permits the construction of it free piston engine linear with improved piston position control, more consistent combustion and improved electrical conversion efficiency.

Abstract: 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.

Abstract: A piston for a free piston engine generator, comprising one or more elements arranged coaxially along a piston shaft wherein the length of the piston is at least five times its maximum diameter, wherein at least one of the elements is formed from a magnetically permeable composite material having isotropic electrical resistivity at least twice that of electrical steel this arrangement providing improved free piston position control, more consistent combustion and improved electrical conversion efficiency.

Abstract: A free-piston engine has an engine cylinder and a single piston member. The single piston member has a double-ended piston that moves within the cylinder, and the piston member partitions the cylinder into two separate chambers, each of which are supplied with a compressible working fluid from one or more intake means. The piston moves over and past the intake means during each stroke such that the fluid is replenished within one chamber while the piston compresses the fluid held in the other chamber.

Abstract: A piston for a free piston engine generator, comprising one or more elements arranged coaxially along a piston shaft wherein the length of the piston is at least five times its maximum diameter, wherein at least one of the elements is formed from a magnetically permeable composite material having isotropic electrical resistivity at least twice that of electrical steel this arrangement providing improved free piston position control, more consistent combustion and improved electrical conversion efficiency.

Abstract: A free-piston engine comprising an engine cylinder and a single piston member comprising a double-ended piston configured to move within the cylinder, wherein the piston member partitions the cylinder into two separate chambers, each of which are supplied with a compressible working fluid from one or more intake means, the piston being arranged to move over and past the intake means during each stroke such that the fluid is replenished within one chamber while the piston compresses the fluid held in the other chamber.

Abstract: A combustion management system for a combustion engine having at least one cylinder with an intake means comprising a sliding port valve and an intake solenoid poppet valve arranged in series and provided at a distance from the cylinder ends, and an exhaust solenoid poppet valve provided at each of the cylinder ends, the system comprising: a valve control means for controlling the intake solenoid poppet valve and the exhaust solenoid poppet valve independently of the position of the piston moving within the cylinder to control the compression and expansion ratios, wherein the piston moves over and past the intake means during each stroke.

Abstract: A piston for an engine generator, comprising alternating laminated core elements and non-magnetising spacer elements arranged along a piston shaft and secured such that contact is maintained between neighbouring elements, wherein the length of the piston is at least at least five times its maximum diameter.