This disclosure relates to a construction machine utilizing battery and hydraulic power and comprising an electronic power unit comprising a battery and an electric motor, a hydraulic pump driven by the electronic power unit and discharging hydraulic fluid, a hydraulic line through which the hydraulic fluid discharged from the hydraulic pump moves, a main control valve installed on the hydraulic line and controlling the supply of the hydraulic fluid to at least one of propulsion devices or various working devices requiring hydraulic power, a bypass cut valve installed downstream of the main control valve on the hydraulic line and configured to open and close the hydraulic line, and a controller initiating a warm-up mode to increase the output of the electronic power unit and open the bypass cut valve.

The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controller 6 includes a target pump pressure setting unit 32 which calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detector 20A/20B based on the operation amount signal and a pump flow rate upper limit setting unit 33 which calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal. The tilt amount of the hydraulic pump 2 is controlled based on the target pump delivery pressure calculated by the target pump pressure setting unit 32, the pump flow rate upper limit calculated by the pump flow rate upper limit setting unit 33, and the delivery pressure of the hydraulic pump 2 detected by a pressure detector 21.

A refuse vehicle includes a chassis and a vehicle body. A variable displacement pump is positioned within the vehicle body and is configured to pump hydraulic fluid from a hydraulic fluid reservoir into a high pressure line of a hydraulic circuit. A lifting system on the vehicle includes at least one actuator in fluid communication with the variable displacement pump, which delivers pressurized hydraulic fluid from the hydraulic fluid reservoir to the actuator through the high pressure line to adjust a position of the actuator. A valve is positioned downstream of the variable displacement pump. In a first valve position, the valve restricts flow outward from the high pressure line. In a second valve position, the valve directs fluid from the high pressure line into a lower pressure line to reduce a hydraulic pressure within the high pressure line and adjust an output parameter of the variable displacement pump.

A hydraulic circuit architecture for a work vehicle includes a pump, a work circuit, a propel circuit, and a circuit selector. The work circuit is connected to an actuator for driving a work component of the work vehicle. The propel circuit includes a motor that is adapted to be connected to a drive train of the work vehicle. The propel circuit also includes an accumulator. The circuit selector selectively connects the pump to the work circuit and the propel circuit. The hydraulic circuit architecture is operable in a first mode and a second mode. In the first mode, the propel circuit is connected to the pump and the work circuit is disconnected from the pump. In the second mode, the work circuit is connected to the pump and the propel circuit is disconnected from the pump. When the hydraulic circuit architecture is in the second mode, stored energy from the accumulator can be used to drive the motor to cause propulsion of the work vehicle.

The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.

A hydraulic system comprises: a hydraulic pump that includes an swash plate; an swash plate angle sensor for measuring the angle of the swash plate; an swash plate driving piston for moving the swash plate of the hydraulic pump in response to changes in pressure applied to a large diameter section; an swash plate control hydraulic line for supplying the large diameter section with a portion of the hydraulic oil discharged by the hydraulic pump; a control valve that controls the flow rate of the hydraulic oil that is following into and out of the large diameter section; an electro-proportional pressure reducing valve for producing pilot pressure that is to be transmitted to one side of the control valve; and a control device for controlling the electro-proportional pressure reducing valve according to an operation signal of an operation device and the angle information from the swash plate angle sensor.

An electrohydraulic control device for an adjustable hydraulic pump system includes a valve device, an electronic control unit and a first fluid sensor. The valve device includes a pressure inlet, a tank outlet and a first electromagnetically actuated valve. An outlet pressure of the first adjustable hydraulic pump system is applied to the pressure inlet. The first fluid sensor detects an actual value of a fluid parameter of the first adjustable hydraulic pump system and transmits it to the electronic control unit. The electronic control unit includes computer-based modeling of the dynamics of the first adjustable hydraulic pump system, and actuates the first electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

A control system includes a cylinder pressure data acquisition unit that acquires cylinder pressure data indicating a pressure of operating oil of a hydraulic cylinder; an operation amount data acquisition unit that acquires operation amount data of an operating device; a pump flow rate calculation unit that calculates a first pump flow rate indicating a flow rate of the operating oil discharged from a first hydraulic pump and a second pump flow rate indicating a flow rate of the operating oil discharged from a second hydraulic pump in a splitting state in which a passage is closed based on the cylinder pressure data and the operation amount data; and a pump control unit that controls the first hydraulic pump and the second hydraulic pump based on the first pump flow rate and the second pump flow rate.

A hydraulic excavator 1 includes an engine 16, a main hydraulic pump 17 driven by the engine 16, a plurality of hydraulic actuators driven with pressure oil discharged from the main hydraulic pump 17, a plurality of flow rate control valves adapted to control the flow rate of pressure oil to be supplied from the main hydraulic pump 17 to the respective hydraulic actuators, a pilot hydraulic pump 18 adapted to supply pressure oil for driving the flow rate control valves, and a controller 15 configured to control the discharge flow rate of the pilot hydraulic pump 18. The controller 15 controls the discharge flow rate of the pilot hydraulic pump 18 such that it becomes equal to the sum of requested pilot flow rates determined in accordance with control commands for the respective flow rate control valves and a preset standby flow rate.

A hydraulic control system for a machine is provided. The hydraulic control system includes a fluid reservoir and a pump motor. The pump motor is fluidly coupled to the fluid reservoir. The pump motor is configured to provide pressurized fluid and to receive fluid to provide a power output to the shaft. The hydraulic control system further includes an actuator and an accumulator fluidly coupled to the pump motor and the actuator. The hydraulic control system further includes an accumulator valve and a controller. The accumulator valve is fluidly coupled between the accumulator and the pump motor. The controller is in communication with the pump motor and the accumulator valve. The controller is configured to detect an operator command to operate the power source; determine pressure at the accumulator; and selectively move the accumulator valve to fluidly connect the accumulator with the pump motor.