A control arrangement for a variable displacement pump includes a pressure control unit and a separate mechanical control unit, each mounted on a housing of the variable displacement pump. The pressure control unit provides pressure control for the variable displacement pump and the mechanical control unit provides rotary feedback control for the variable displacement pump.

Pump, in particular a high-pressure fuel pump, having at least one pump element (10) which has a pump piston (12) which is driven in a reciprocating movement by way of a drive shaft (14) with at least one cam (16; 160) and delimits a pump working chamber (24) which can be filled with delivery medium via an inlet valve (26) during the suction stroke of the pump piston (12). The at least one cam (60; 160) of the drive shaft (14) is a multiple cam with a plurality of cam delivery regions (16a, 16b) for the delivery strokes of the pump piston (12), or a plurality of single or multiple cams (160) with in each case at least one cam delivery region (160a, 160b) for the delivery strokes of the pump piston (12) are provided which are arranged next to one another in the direction of the rotational axis (15) of the drive shaft (14). The cam profiles of the cam delivery regions (16a, 16b) of the at least one multiple cam (16) or the cam profiles of the cam delivery regions (160a, 160b) of the single cams (160) are of different configuration.

The invention relates to a pump unit that can be driven by an electric motor, in particular for providing vacuum for a pneumatic brake booster, including a pump housing that can be closed by a working-chamber cover and at least one elastic displacement element, wherein a working chamber is bounded between the displacement element and the working-chamber cover and wherein inlet valves and outlet valves and inlet channels and outlet channels associated with the valves are associated with the working chamber. According to the invention, in order to reduce noise emissions, devices for reducing a contact surface between the working-chamber cover and the pump housing are provided.

A pump system is disclosed. The pump system includes a cavity (102) comprising one or more inlet check valves (120, 122) and one or more outlet check valves (124, 126). A piston (104) having an enlargement (106) at a substantially middle portion of the piston (104). The piston (104) is capable of moving within the cavity (102) for forming a first chamber (116) and a second chamber (118), wherein up movement of the piston (104) the volume in the first chamber (112) is increased and simultaneously the volume in the second chamber (118) is decreased and vice versa.

A control device for a fuel injection system includes a CPU which generates a drive signal for instructing execution of compression by a feel pump; a fuel pump drive circuit which controls application of electric power to a solenoid of the feel pump based on the drive signal; a boost circuit provided with a capacitor for storing electric power to be used for driving an injector; a charging circuit which leads a current generated when the application of electric power to the solenoid is stopped to the capacitor; and an excess electric power consumption circuit which consumes excess electric power of the capacitor. While feel injection from the injector is stopped, the CPU counts the number of times the feel pump is driven and turns off the drive signal so as to stop driving the feel pump as soon as the drive count has exceeded a predetermined count value.

The present disclosure provides a high-pressure fuel pump including a barrel unit, a plunger, and a camshaft assembly having an eccentric cam lobe including a surface of the lobe. A follower is provided between the plunger and the surface of the lobe of the camshaft assembly to facilitate translation between the rotational movement of the camshaft assembly to axial movement of the plunger. The follower includes arcuate surfaces configured to mate with corresponding arcuate surfaces of the lobe of the cam shaft assembly and the plunger, respectively.

A prime mover and a plurality of hydraulic actuators, a hydraulic machine having a rotatable shaft in driven engagement with the prime mover and comprising working chambers, a hydraulic circuit between working chambers of the hydraulic machine and the hydraulic actuators, each working chamber of the hydraulic machine comprising a low-pressure and high-pressure valves regulating the flow of hydraulic fluid between the working chamber and a corresponding low-pressure manifold and a high-pressure manifold. The hydraulic machine being configured to actively control the low-pressure valves of the working chambers to select the net displacement of hydraulic fluid by each working chamber on each cycle of working chamber volume, and thereby the net displacement of hydraulic fluid by the working chambers, responsive to a demand signal, wherein the apparatus further comprises a controller configured to calculate the demand signal in response to a measured property of the hydraulic circuit or actuators.

Embodiments of the invention provide a pump assembly for a hydraulic tool. The pump assembly can include a reciprocating element that is configured to move between a retracted position and an extended position, a cam surface in the reciprocating element that can engage cam followers, a rotating element that can receive rotational input, and a base that can at least partially surrounds the rotating element. Movement of the cam followers along the cam surface can move the reciprocating element from the retracted position to the extended position.

A reciprocating pump capable of reducing its overall size by suppressing the size of an entire drive unit. A plurality of piston parts move in the same direction and draw fluid into a plurality of pump chambers and discharge the fluid. The pump chambers are adjacent to each other. A motor has a drive shaft between the centers of piston parts located at both ends in the installation direction of the pump chambers and oriented in a direction substantially orthogonal to the installation direction of the pump chambers and substantially orthogonal to the moving direction of the piston parts. A plurality of cams are aligned adjacent each other in the axial direction on the motor drive shaft. The cams are linked to the piston parts so that the cams cause the reciprocal movement of the piston parts.

A pump includes a pair of valves, coupled to a camshaft that selectively opens and closes the valves such that when one valve opens the other valve closes. The valves are in fluid communication with a piston chamber. A crankshaft operates a piston in a piston cylinder with the opening and closing of the valves such that as the piston is drawn from the piston chamber, the inlet valve is open and the outlet valve is closed and when the piston is forced into the chamber, the outlet valve is open and the inlet valve is closed. The camshaft and crankshaft are coupled together to cause synchronous operation of the valves and piston.