Caterpillar Inc.

Shin Caterpillar Mitsubishi Ltd.

Caterpillar Sarl

Michael Schwab

Jiao Zhang

Pengfei Ma

Tonglin Shang

Kalpesh Patel

Douglas W Koehler

A hydraulic apparatus and a method of operating the hydraulic apparatus are disclosed. The hydraulic apparatus includes a flow control module, a first pump fluidly coupled to the flow control module via a first conduit, a first rotating group fluidly coupled to the flow control module via a second conduit, a first actuator fluidly coupled to the flow control module, a second actuator fluidly coupled to a second pump, a first accumulator, and a controller operatively coupled to the flow control module, the first charge valve, and the discharge valve. The first rotating group is configured to perform a pumping function and a motor function. The first accumulator is in selective fluid communication with the first actuator via a third conduit and a first charge valve, the second actuator via a fourth conduit and the first charge valve, and the first rotating group via a discharge valve.

Hybrid apparatus and method for hydraulic systems

This disclosure relates to a hydraulic system and method that converts the kinetic energy generated by the operation of a swing motor into hydraulic potential energy and reuses the hydraulic potential energy for swing motor acceleration. An accumulator can be provided for storing exit oil from the swing motor that is pressurized by the inertia torque applied on the moving motor via movement of an upper structure of a machine. The pressurized oil in the accumulator can be reused to accelerate the swing motor by supplying pressurized oil to the swing motor.

Control system for recovering swing motor kinetic energy

A hydraulic system for a work machine is disclosed. The hydraulic system has a reservoir configured to hold a supply of fluid and a source configured to pressurize the fluid. The hydraulic system also has a fluid actuator, a first valve, and a second valve. The first valve is configured to selectively fluidly communicate the source with the fluid actuator to facilitate movement of the fluid actuator in a first direction. The second valve is configured to selectively fluidly communicate the fluid actuator with the reservoir to facilitate movement of the fluid actuator in the first direction. The hydraulic system further has a proportional pressure compensating valve configured to control a pressure of a fluid directed between the fluid actuator and the reservoir.

Hydraulic system having a post-pressure compensator

A hydraulic system may include a hydraulic actuator. The hydraulic system may also include a pump having a pump inlet and a pump outlet, and the pump may be configured to supply fluid to the hydraulic actuator. The hydraulic system may further include an energy recovery system operatively connected between the hydraulic actuator and the pump. The energy recovery system may be configured to store fluid from the hydraulic actuator under an overrunning load condition, and the stored fluid may be directed through the pump inlet and into the hydraulic actuator.

Hydraulic system for recovering potential energy

A pressure compensator for use in a control system for an electro hydraulic-implemented work element being operated through the use of operator input control mechanisms generating operator input signals upon the application thereof, the control system including an actuator coupled thereto for controlling the operation thereof, the pressure compensator determining a pressure compensator coefficient to be applied to an operator input signal to compensate for changes of pressure drop across a valve in communication with the actuator. The pressure compensator coefficient is used to produce an input flow control signal for inputting to the valve to control the amount of hydraulic fluid that flows therethrough to the actuator so that a desired velocity of the actuator is achieved.

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Crest Hill, IL, United States of America

Michael Schwab