A combustion driven fastener hand tool is disclosed having a fuel system subassembly including a fuel nozzle and a metering valve, disposed in a common bore of the combustion driven fastener apparatus. The metering valve comprises a hollow cylindrical housing having a cap at each end and a central dual valve stem therebetween. Movement of the dual central valve stem closes an inlet valve at one end and opens an outlet valve at an opposite end in a coordinated manner to release a metered amount of fuel through the outlet valve while preventing additional fuel through the inlet valve. The combustion driven fastener hand tool includes numerous other features affording improvements over the prior art.

A combustion driven fastener hand tool is disclosed having a fuel system subassembly including a fuel nozzle and a metering valve, disposed in a common bore of the combustion driven fastener apparatus. The metering valve comprises a hollow cylindrical housing having a cap at each end and a central dual valve stem therebetween. Movement of the dual central valve stem closes an inlet valve at one end and opens an outlet valve at an opposite end in a coordinated manner to release a metered amount of fuel through the outlet valve while preventing additional fuel through the inlet valve. The combustion driven fastener hand tool includes numerous other features affording improvements over the prior art.

A free piston apparatus includes a piston receptacle in which a piston device having a piston is reciprocable along an axis. The piston receptacle includes a combustion chamber delimited by a wall arrangement forming an inlet opening for the supply of fresh gas and an outlet opening for the removal of exhaust gas. The free piston apparatus includes an inflow device, which has the inlet opening and is configured such that fresh gas flowing into the combustion chamber is directed to an incident flow region in the combustion chamber arranged offset axially to the inlet opening, which incident flow region is arranged off-center relative to the axis. A method for operating a free piston apparatus includes operating an inflow device which has an inlet opening configured such that fresh gas is directed to an incident flow region in a combustion chamber offset axially to the inlet opening.

A free piston apparatus includes a piston receptacle in which a piston device having a piston is reciprocable along an axis. The piston receptacle includes a combustion chamber delimited by a wall arrangement forming an inlet opening for the supply of fresh gas and an outlet opening for the removal of exhaust gas. The free piston apparatus includes an inflow device, which has the inlet opening and is configured such that fresh gas flowing into the combustion chamber is directed to an incident flow region in the combustion chamber arranged offset axially to the inlet opening, which incident flow region is arranged off-center relative to the axis. A method for operating a free piston apparatus includes operating an inflow device which has an inlet opening configured such that fresh gas is directed to an incident flow region in a combustion chamber offset axially to the inlet opening.

A free piston apparatus includes a piston receptacle in which a piston device having a piston is linearly reciprocable. The piston receptacle includes or forms a combustion chamber delimited by a wall arrangement forming a first opening and a second opening. The openings include an inlet opening for the supply of fresh gas and an outlet opening for the removal of exhaust gas for a uniflow scavenging of the combustion chamber. Movement of the piston device is controllable by a control device. The bottom dead center of the piston can be adjustable such that when the piston adopts the bottom dead center, the first opening is partially unblocked and partially blocked for adjusting a free cross sectional area of the first opening. An opening duration can also be adjustable. A method for operating a free piston apparatus includes controlling movement of a piston device with a control device.

A free piston apparatus includes a piston receptacle in which a piston device having a piston is linearly reciprocable. The piston receptacle includes or forms a combustion chamber delimited by a wall arrangement forming a first opening and a second opening. The openings include an inlet opening for the supply of fresh gas and an outlet opening for the removal of exhaust gas for a uniflow scavenging of the combustion chamber. Movement of the piston device is controllable by a control device. The bottom dead center of the piston can be adjustable such that when the piston adopts the bottom dead center, the first opening is partially unblocked and partially blocked for adjusting a free cross sectional area of the first opening. An opening duration can also be adjustable. A method for operating a free piston apparatus includes controlling movement of a piston device with a control device.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a work stroke from one end to another. The work stroke may include an expansion stroke portion, a momentum stroke portion, and a compression stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and a location outside the cylinder.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a work stroke from one end to another. The work stroke may include an expansion stroke portion, a momentum stroke portion, and a compression stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and a location outside the cylinder.

Multiphase electromagnetic machines, such as free-piston engines or compressors, may require, or supply, a pulsed power profile from or to a DC bus, respectively. The pulsed power profile may include relatively large fluctuations in instantaneous power. Sourcing, sinking, or otherwise exchanging power with an AC grid, via an inverter, may be accomplished by using an energy storage device and a DC-DC converter coupled to a DC bus. The energy storage device may aid in smoothing the pulsed power profile, while the DC-DC converter may aid in reducing fluctuations in voltage across a DC bus due to energy storage in the energy storage device.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a work stroke from one end to another. The work stroke may include an expansion stroke portion and a non-expansion stroke portion. The non-expansion stroke portion may include a momentum stroke portion, and a compression stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and other locations.