Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A variable displacement hydraulic unit with a housing in which a rotating group is housed, wherein the displacement volume of the rotating group is variably adjustable by means of a swivel element able to tilt around a tilt axis perpendicular to the rotational axis of the rotating group. The swivel element can be actuated by at least one servo unit including a servo cylinder integrated in the housing and a servo piston moveably within the servo cylinder. The head of the servo piston can be pressurized in the servo cylinder such that a movement of the servo piston coupled to the swivel element via a servo piston shaft tilts the swivel element; wherein the servo unit is located within the housing on that side of the swivel element on which no rotating group is located, and follow a working direction substantially parallel to the rotational axis of the rotating group.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A system includes a pump. The pump includes a piston configured to axially reciprocate within a body. The axial movement of the piston activates a first chamber valve and a second chamber valve. The system also includes a main valve configured to direct a flow to the pump to facilitate the axial movement which then transfers a fluid from a reservoir to a spray applicator. The system includes a runaway valve system fluidly coupled to the main valve and configured to detect a runaway state of the pump. The runaway valve system is configured to direct the main valve to stop operation of the pump in response to detection of the runaway state.

A linear compressor includes: a piston configured to reciprocate along an axial direction of the linear compressor; a resonance spring configured to elastically support the piston along the axial direction; a motor assembly configured to provide a driving force to the piston, the motor assembly including a magnet that is disposed radially outside the piston; and a supporter configured to be coupled to the piston, the magnet, and the resonance spring. The supporter includes: a piston coupler coupled with the piston; a magnet coupler coupled with the magnet; and a spring coupler coupled with the resonance spring. The piston coupler, the magnet coupler, and the spring coupler are integrally formed by aluminum die casting.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A fuel supply device includes: a linear actuator; a reciprocating pump having a boosting piston driven by the linear actuator and configured to reciprocate in an axial direction, the reciprocating pump being configured to suck the fuel when the boosting piston moves in a first direction and configured to boost and eject the fuel when the boosting piston moves in a second direction; and a controller configured to control driving of the linear actuator so as to adjust an amount of the fuel ejected from a boosting cylinder per reciprocating time by adjusting a ratio of a fuel ejection time and a fuel suction time of the reciprocating pump without changing the reciprocating time of the boosting piston in accordance with a load of the internal combustion engine. The adjustment adjusts a stroke length of the boosting piston and a moving speed of the boosting piston in the second direction.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

Methods and systems for controlling the timing of a fluid driven positive displacement pump (FDPDP) are disclosed using pump inlet pressure, flow rate and time domain control. Pressure is thus controlled at various flow rates of fluids to be pumped in subsea environments. The FDPDP includes a plurality of pressure vessels connected by piping, each vessel having two chambers. One chamber is connected to a source of fluid to be pumped and the other chamber is connected to a source of driving fluid. The methods synchronize pumping chambers that have no mechanical means to control timing between each pumping chamber. The control methods described utilize algorithms which receive feedback from the pumping system to control the pumping sequence and adapt to any parameter changes to maintain a constant range of desired pressure.

Methods and systems for controlling the timing of a fluid driven positive displacement pump (FDPDP) are disclosed using pump inlet pressure, flow rate and time domain control. Pressure is thus controlled at various flow rates of fluids to be pumped in subsea environments. The FDPDP includes a plurality of pressure vessels connected by piping, each vessel having two chambers. One chamber is connected to a source of fluid to be pumped and the other chamber is connected to a source of driving fluid. The methods synchronize pumping chambers that have no mechanical means to control timing between each pumping chamber. The control methods described utilize algorithms which receive feedback from the pumping system to control the pumping sequence and adapt to any parameter changes to maintain a constant range of desired pressure.