Caterpillar Inc.

Randal Peterson

Pengfei Ma

Jiao Zhang

Tonglin Shang

Peter Spring

Rustu Cesur

Dayao Chen

Aleksandar M Egelja

Bryan Jacob Hillman

Lawrence J Tognetti

John Ferraz, Jr

Salik Abdul Syed

Mike T Verkuilen

A hydraulic system for a machine is disclosed. The system may have a pump and a motor driven by pressurized fluid from the pump. An accumulator is configured to receive fluid discharged from the motor and to discharge fluid to the motor. The system may include a first valve to selectively communicate the higher pressure of conduits coupled between the pump and motor to the accumulator. A second valve and a third valve can be used to facilitate charging and discharging of the accumulator. The system may include a controller configured to implement a plurality of modes of operation, which each mode of operation may include a different combination of motor deceleration and motor acceleration segments during which the accumulator receives and discharges fluid, respectively. An input may be used to determine the segment of the work cycle.

Hydraulic system having energy recovery

A hydraulic control system for a machine is disclosed. The hydraulic control system may have a tank, a pump configured to draw fluid from the tank and pressurize the fluid, an actuator, and a control valve configured to direct fluid from the pump to the actuator and from the actuator to the tank to move the actuator. The hydraulic system may also have a main relief valve movable away from a closed position to pass pressurized fluid to the tank when a pressure of the fluid directed to the actuator exceeds a first threshold pressure, and a controller in communication with the pump. The controller may be configured to selectively reduce a displacement of the pump after the main relief valve has moved away from the closed position when the pressure of the fluid directed to the actuator exceeds a second threshold pressure.

Hydraulic control system having over-pressure protection

A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, a swing motor, and at least one control valve configured to control fluid flow between the pump, the swing motor, and the tank. The hydraulic system may also have an accumulator configured to selectively receive pressurized fluid discharged from the swing motor and selectively supply pressurized fluid to the swing motor, at least one accumulator valve, and a controller. The controller may be configured to receive input indicative of a difference between desired and actual speeds of the swing motor, and determine if the swing motor is accelerating or decelerating based on the difference. The controller may also be configured to control the at least one accumulator valve to cause the accumulator to selectively receive or supply pressurized fluid only when the swing motor is accelerating or decelerating.

Hydraulic control system having swing motor recovery

A hydraulic control system for a machine is disclosed. The hydraulic control system may have a work tool movable to perform an excavation cycle having a plurality of segments, a motor configured to swing the work tool during the excavation cycle, and a pump configured to pressurize fluid directed to drive the motor. The hydraulic control system may also have at least one accumulator configured to selectively receive fluid discharged from the motor and to discharge fluid to the motor during the plurality of segments, and a controller configured to implement a plurality of modes of operation. Each of the plurality of modes of operation includes a different combination of segments during which the at least one accumulator receives and discharges fluid.

Hydraulic control system having swing motor energy recovery

An energy recovery retrofit kit for a hydraulic control system is disclosed. The energy recover retrofit kit may have a first accumulator and a second accumulator. The energy recover retrofit kit may also have a recovery valve block fluidly connectable between an existing pump and an existing motor of the hydraulic system. The recovery valve block may be configured to selectively fluidly communicate the first and second accumulators with the existing motor.

Hydraulic control system having energy recovery kit

A hydraulic control system for a machine is disclosed. The hydraulic control system may have a work tool movable through segments of an excavation cycle, a motor configured to swing the work tool during the excavation cycle, at least one accumulator configured to selectively receive fluid discharged from the motor and to discharge fluid to the motor during the excavation cycle, and a controller. The controller may be configured to receive input regarding a current excavation cycle of the work tool, and make a determination based on the input that the current excavation cycle is associated with one of a set of known modes of operation. The controller may be further configured to cause the at least one accumulator to receive fluid and discharge fluid during different segments of the excavation cycle based on the determination.

A method of operating a hydraulic system is disclosed. The method includes holding an implement configuration in an orientation. The method also includes sensing a pressure within a chamber of a hydraulic actuator associated with the implement configuration when the implement configuration is in the orientation and comparing a first signal indicative of the first sensed pressure with a first pressure value. The method further includes selecting a first functional relationship from among a plurality of stored functional relationships if the first signal is greater than the first pressure value and selecting a second functional relationship from among the plurality of stored functional relationships if the first signal is less than the first pressure value. The method includes controlling the hydraulic actuator based on the selected functional relationship.

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Peoria, IL, United States of America

Randal Peterson