Caterpillar Inc.

Purdue Research Foundation

Lawrence J Tognetti

Jiao Zhang

Pengfei Ma

Bryan Jacob Hillman

Tonglin Shang

Dayao Chen

Patrick Opdenbosch

Rustu Cesur

Peter Spring

Tetsuya Yoshino

Jeffrey Lee Kuehn

Brad Allen Edler

Jason Brinkman

John Ferraz, Jr

Christopher Alan Williamson

Bryan A Johnson

Randal Peterson

Viral S Mehta

Chris R Cesur

A hydraulic control system is disclosed for use in a machine. The hydraulic control system may have a work tool, a motor configured to swing the work tool, a tank, a pump configured to draw fluid from the tank and pressurize the fluid, and a control valve operable to control fluid flow from the pump to the motor and from the motor to the tank via first and second chamber passages to affect motion of the motor. The hydraulic control system may also have an accumulator, and an accumulator circuit configured to selectively direct fluid discharged from the motor to the accumulator for storage and to direct stored fluid from the accumulator to the motor to assist the motor. The hydraulic control system may further have a selector valve configured to selectively connect a higher pressure one of the first and second chamber passages with the accumulator, and a single pressure relief valve disposed within the accumulator circuit and configured to relief pressure from opposing sides of the motor.

Hydraulic control system having swing motor energy recovery

A hydraulic control system for a machine is disclosed. The hydraulic control system may have a tank, a pump, and a fluid actuator. The hydraulic control system may further have an accumulator configured to selectively receive pressurized fluid discharged from the fluid actuator and selectively supply pressurized fluid to the fluid actuator. The hydraulic control system may also have a pressure sensor configured to generate a signal indicative of a pressure of the accumulator, a charge valve, a discharge valve, and a controller in communication with the control valve, the charge valve, and the discharge valve. The controller may be configured to detect stall of the fluid actuator, to make a comparison of the pressure of the accumulator with a threshold pressure, and to selectively move the charge valve to charge the accumulator or move the discharge valve to discharge the accumulator during the stall based on the comparison.

Hydraulic control system having swing energy recovery

A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, an actuator, and a control valve configured to direct fluid from the pump to the actuator and from the actuator to the tank. The hydraulic control system may also have a pressure sensor to generate a first signal indicative of a pressure differential across the control valve, an operator input device to generate a second signal indicative of a desired movement of the actuator, and a controller. The controller may be configured to make a first determination of an opening amount of the control valve based on the second signal, and to make a second determination based on the first signal of whether the opening amount will result in overspeeding of the actuator. The controller may also be configured to reduce the opening amount based on the second determination.

Hydraulic control system having electronic flow limiting

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 system includes a variable-displacement first pump, an over-center variable-displacement first travel motor selectively connected to receive fluid pressurized by the first pump in a closed loop manner, and an over-center variable-displacement second travel motor selectively connected to receive fluid pressurized by the first pump in parallel with the first travel motor in a closed loop manner. The hydraulic system also includes a linear actuator selectively connected to receive fluid pressurized by the first pump in parallel with the first and second travel motors in a closed loop manner.

Meterless hydraulic system having flow sharing and combining functionality

A hydraulic system includes a variable-displacement first pump, a variable-displacement second pump, and a first actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner. The hydraulic system also includes a second actuator selectively connected either to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner. The hydraulic system further includes a variable-displacement rotary actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner.

A hydraulic system includes a variable-displacement first pump and a variable-displacement second pump. The hydraulic system also includes a first actuator selectively connected either to the first pump in a closed loop manner and not the second pump, to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner. The hydraulic system further includes a second actuator and a variable-displacement rotary actuator that are each selectively connected either to the first pump in a closed loop manner and not the second pump, to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner.

A method for overpressure control in a hydraulic system having multiple hydraulic pumps, with each hydraulic pump being connected by a respective hydraulic circuit for actuating a single respective hydraulic actuator, includes actuating a first variable displacement hydraulic pump, the first hydraulic pump being fluidly linked by a first hydraulic circuit to a first hydraulic actuator for powering the first hydraulic actuator. Upon detecting a pressure that exceeds a predetermined threshold pressure, the flow rate of the first hydraulic pump is electronically modified to a second flow rate lower than the first flow rate whereby the pressure in the first hydraulic circuit is reduced to a pressure that is below the predetermined threshold pressure.

Electronic high hydraulic pressure cutoff to improve system efficiency

A swing energy recovery system for a machine is disclosed. The swing energy recovery system may have a pump configured to pressurize fluid, a motor driven by a flow of pressurized fluid from the pump, and an energy recovery arrangement configured to receive pressurized fluid discharged from the motor and selectively supply pressurized fluid to the motor. The swing energy recovery system may also have a pressure relief valve associated with the motor, and a controller in communication with the energy recovery arrangement and the pressure relief valve. The controller may be configured to selectively adjust a setting of the pressure relief valve based on an operating condition of the energy recovery arrangement.

Energy recovery system having accumulator and variable relief

A hydraulic system for a machine is disclosed. The hydraulic system may have a first pump with variable displacement and being load-sense controlled, and a first hydraulic circuit associated with the first pump. The hydraulic system may also have a second pump with variable displacement and being electro-hydraulically controlled, and a second hydraulic circuit associated with the second pump. The hydraulic system may further have a flow-sharing valve arrangement configured to selectively share fluid flow between the first and second hydraulic circuits.

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Peoria, IL, United States of America

Lawrence J Tognetti