Abstract: A hydraulic control system for a work implement is provided. The hydraulic control system includes first hydraulic circuit and second hydraulic circuit. The first hydraulic circuit includes a selector valve and a pair of hydraulic cylinder assembly. Each hydraulic cylinder assembly includes a head end, a rod end, a cylinder, and a rod. The selector valve is configured to operate in neutral position and at least one operating position to selectively connect either the head end or the rod end to a fluid source, and the other of the head end or the rod end to fluid tank. The second hydraulic circuit includes a counterbalance valve and a shuttle valve. The counterbalance valve selectively connects the head end to the fluid tank. The shuttle valve is configured to maintain predefined pressure at relief side pressure port of the counterbalance valve to maintain a threshold pressure at the head end.

Abstract: A hydraulic system includes an engine; at least one hydraulic pump operatively coupled to the engine for transfer of mechanical power therebetween; and a controller operatively coupled to the engine and the at least one hydraulic pump. The controller is configured to determine a lug speed error as a difference between a target lug speed value and a speed of the engine, set at least one closed-loop gain to zero when the speed of the engine is greater than or equal to the target lug speed value, set the at least one closed-loop gain to a non-zero value when the speed of the engine is less than the target lug speed value, generate a pump control signal by scaling the lug speed error by the at least one closed-loop gain.

Abstract: A hydraulic system includes an engine; at least one hydraulic pump operatively coupled to the engine for transfer of mechanical power therebetween; and a controller operatively coupled to the engine and the at least one hydraulic pump. The controller is configured to determine a lug speed error as a difference between a target lug speed value and a speed of the engine, set at least one closed-loop gain to zero when the speed of the engine is greater than or equal to the target lug speed value, set the at least one closed-loop gain to a non-zero value when the speed of the engine is less than the target lug speed value, generate a pump control signal by scaling the lug speed error by the at least one closed-loop gain.

Abstract: A hydraulic control system for a work implement is provided. The hydraulic control system includes first hydraulic circuit and second hydraulic circuit. The first hydraulic circuit includes a selector valve and a pair of hydraulic cylinder assembly. Each hydraulic cylinder assembly includes a head end, a rod end, a cylinder, and a rod. The selector valve is configured to operate in neutral position and at least one operating position to selectively connect either the head end or the rod end to a fluid source, and the other of the head end or the rod end to fluid tank. The second hydraulic circuit includes a counterbalance valve and a shuttle valve. The counterbalance valve selectively connects the head end to the fluid tank. The shuttle valve is configured to maintain predefined pressure at relief side pressure port of the counterbalance valve to maintain a threshold pressure at the head end.

Abstract: A method for estimating a remaining useful life of a filter is provided. The method includes determining, at a processor of a machine, a scaled delta pressure of the filter in the machine based on an input from a plurality of sensors. The method includes determining a plugging parameter of the filter based upon a non-linear relationship between the scaled delta pressure and the plugging parameter of the filter. The method includes estimating the remaining useful life of the filter at a time instant based upon a contamination rate estimate, the contamination rate estimate being determined based upon the determined plugging parameter. The method includes controlling, using a signal, a flow of a fluid entering the filter based on the plugging parameter, and outputting the estimated remaining useful life of the filter on a display.

Abstract: A hydraulic system is disclosed that has first and second passages connecting a pump to an actuator in closed-loop manner, and first and second load-holding valves within the first and second passages. The hydraulic system may also have a regeneration valve connected to the first and second passages between the actuator and the first and second load-holding valves to selectively connect the first and second passages. The hydraulic system may further have a controller configured to cause a control valve to simultaneous move the first and second load-holding valves toward flow-blocking positions when pump displacement is about zero. The controller may also be configured to selectively cause the regeneration valve to connect the first and second passages when pump displacement is non-zero, and to cause only one of the first and second load-holding valves to move to its flow-blocking position when the regeneration valve connects the first and second passages.

Abstract: A hydraulic system hydraulic system includes a variable displacement pump, and a variable displacement first travel motor selectively fluidly connected to the pump in a closed-loop manner. The system also includes a first switching valve associated with the first travel motor and configured to selectively switch a flow direction of fluid passing through the first travel motor from the pump. The system further includes a variable displacement second travel motor selectively fluidly connected to the pump in a closed-loop manner. The system also includes a second switching valve associated with the second travel motor and configured to selectively switch a flow direction of fluid passing through the second travel motor from the pump.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a rotary actuator, a linear actuator, and a closed-loop circuit fluidly connecting the pump to the rotary and linear actuators. The hydraulic system may also have at least one valve configured to switch fluid flow direction from the pump through the linear actuator during fluid flow in a single direction through the rotary actuator.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a first actuator, and a meterless circuit connecting the first actuator to the pump. The hydraulic system may also have a second actuator connected to the meterless circuit in parallel with the first actuator. The second actuator may be a variable-area linear actuator.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A hydraulic system is disclosed. The hydraulic system may have an over-center, variable-displacement pump, an actuator, and first and second passages that create a closed-loop circuit. The hydraulic system may also have first and second check valves disposed in the first and second passages, respectively, to allow flow only from the pump to the actuator. The hydraulic system may further have a first bypass line connecting the first passage at a location between the actuator and the first check valve to the first passage at a location between the first check valve and the pump, and a second bypass line connecting the second passage at a location between the actuator and the second check valve to the second passage at a location between the second check valve and the pump. The hydraulic system may additionally have a valve configured to control flow through the first and second bypass lines.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a primary pump, a hydraulic actuator, and first and second passages fluidly connecting the primary pump to the hydraulic actuator in a closed-loop manner. The hydraulic system may also have a charge circuit, a makeup valve movable to selectively allow charge fluid from the charge circuit to enter the first or second passages, and at least one restricted pilot passage configured to direct pilot fluid to the makeup valve to move the makeup valve and allow the charge fluid into the first and second passages.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a tank, a displacement actuator having first and second chambers, a regeneration valve, and a load-holding valve. The hydraulic system may also have a displacement control valve including a valve element, and a stationary cage portion at least partially forming a high-pressure passage fluidly connecting the pump and valve element, a low-pressure passage fluidly connecting the valve element and tank, a first displacement actuator passage fluidly connecting the valve element and first chamber, a second displacement actuator passage fluidly connecting the valve element and second chamber, a load-holding control passage fluidly connecting the valve element and load-holding valve, and a regeneration control passage fluidly connecting the valve element and regeneration valve.

Abstract: A hydraulic system includes a first pump, a first actuator fluidly connected to the first pump via a first closed-loop circuit, a second pump, and a second actuator fluidly connected to the second pump via a second closed-loop circuit. The system also includes a third pump, a third actuator fluidly connected to the third pump via a third closed-loop circuit, a fourth pump, and a fourth actuator fluidly connected to the fourth pump via a fourth closed-loop circuit. The system further includes a first combining valve configured to combine fluid from the first and second circuits, a second combining valve configured to combine fluid from the second and third circuits, and a third combining valve configured to combine fluid from the third and fourth circuits. The system also includes a fourth combining valve configured to combine fluid from the first and fourth circuits.

Abstract: A method of controlling a hydraulic system includes providing fluid to a first actuator with a first pump via a first closed-loop circuit of a machine, and providing fluid to a second actuator with a second pump via a second closed-loop circuit of the machine. The method also includes providing fluid to a third actuator with a third pump via a third closed-loop circuit of the machine, and providing fluid to a fourth actuator with a fourth pump via a fourth closed-loop circuit of the machine. The method further includes forming a combined flow of fluid including fluid from the first circuit and fluid from at least one of the second, third, and fourth circuits, and directing the combined flow to the first actuator while providing fluid to the actuator of the at least one of the second, third, and fourth circuits.

Abstract: 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.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a hydraulic actuator, and first and second passages fluidly connecting the pump to the hydraulic actuator in a closed-loop. The hydraulic system may also have a control valve, and a load-holding valve configured to selectively lock movement of the hydraulic actuator. The load-holding valve may include a valve block at least partially defining a pump passage, an actuator passage, a control passage, a restricted passage connecting the actuator passage and the control passage, and a bypass passage connecting the actuator passage and the control passage. The load-holding valve may also include a valve element movable between a first position at which flow between the pump and the hydraulic actuator is blocked, and a second position at which fluid is allowed to flow between the pump and the hydraulic actuator, the valve element being spring-biased toward the first position.

Abstract: A hydraulic system includes an actuator, a pump, rod side and cap side fluid connections between the pump and the rod and cap side chambers, respectively, at least one selectively actuatable regeneration valve that selectively provides flow from the cap side fluid connection to the rod side fluid connection, and a controller. The controller controls the pump to selectively vary the flow rate of the pump in response to a commanded motion to control movement of the piston. The controller actuates the regeneration valve during a retraction of the piston into the cylinder when pump is acting as a motor.