A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. The pump body closes the pressure chamber on a side opposite to a plunger. The plunger reciprocates within the cylinder to vary a volume of the pressure chamber. The large-diameter portion provided at an end of the plunger on a side protruding to the pressure chamber has an outside diameter larger than an inside diameter of the cylinder and smaller than an inside diameter of the pressure chamber. In this case, the large-diameter portion is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

A high-pressure fuel pump includes a pump housing which defines a pumping chamber, a fuel inlet which allows low-pressure fuel into the pumping chamber, a fuel outlet which allows high-pressure fuel out of the pumping chamber, and a plunger bore which extends along an axis and opens into the pumping chamber. The high-pressure fuel pump also includes a pumping plunger which reciprocates within the plunger bore along the axis such that reciprocation of the pumping plunger within the plunger bore increase and decreases a volume of the pumping chamber. The pumping plunger includes a sealing ring groove which is concentric with the plunger bore, the sealing ring groove including a sealing ring therein which engages the plunger bore in an interference fit. A diametric clearance greater than 12 microns is provided between the pumping plunger and the plunger bore.

A multi piston machine includes a rotor, pistons, a first control valve, and a second control valve. The pistons abut against a cam surface with multiple lobes. The machine is switchable between at least three non-zero displacement volumes using the first and the second control valves. The first control valve is connected to a first and a third fluid chamber. The second control valve is connected to a second and a fourth fluid chamber. The first and the second control valve are connected to first and the second working port respectively. A third number of second control openings is twice a second number of the lobes. There is a first and a second group of the second control openings. Adjacent second control openings belong to a different first or second group. The second control openings of the first group are either connected to the first or the second fluid chamber.

The invention relates to a method of venting a synthetically commutated hydraulic pump (2). The connecting fluid conduits (8, 16), connecting said synthetically commutated hydraulic pump (2) with a fluid reservoir (7) is vented at least on start-up of the synthetically commutated hydraulic pump (2), using a fluid intake device (14, 17, 20) that connects to a fixed displacement pump (3).

A power piston in a power cylinder borehole of a hydraulic block of a hydraulic power unit of a hydraulic power vehicle braking system is only guided radially in an axially delimited guide section. The power cylinder borehole is configured with a larger diameter axially outside the guide section. A brake fluid channel extends through the guide section up to an opening of a brake fluid line.

A suction valve of a high-pressure fuel pump for a vehicle includes a housing having an inlet through which a fuel is introduced and a pump chamber configured to press the fuel, a valve installation space arranged between the inlet and the pump chamber, and a solenoid part provided with a rod for performing a linear reciprocal motion, and further includes a valve sleeve inserted into the valve installation space and formed with a flow hole, a valve spring seated on the valve sleeve, a valve plate elastically supported by the valve spring, and moving in conjunction with the rod, and a valve sheet formed with an introduction hole opened and closed by the valve plate, in which the valve sleeve is slid and inserted into the valve installation space, and the valve sheet is fitted into and fastened to the valve installation space to support the valve sleeve.

A micro-pneumatic control unit comprising a plurality of control channels for generating the control pressures in a pneumatically actuated multi-channel coating head for coating components with a coating agent, a control channel being characterized by a valve element comprising a valve bore in a valve plate and a diaphragm layer which is below the valve plate and is configured as a diaphragm closing element in the region of the valve bore, the shape of which diaphragm closing element defined by recesses positioned laterally with respect to the valve bore, by a micro-actuator having a plunger that actuates the diaphragm closing element through the valve bore such that the valve element opens, by a second micro-pneumatic element connected in series with the valve element, the control pressure developing and a cavity located at the connection node thereof, which cavity is connected to at least one pneumatically operated coating agent ejector, and by a pneumatic pressurization of the micro-pneumatic control unit, which is directed such that, with respect to the valve element, there is a pressure gradient from the diaphragm closing element to the valve bore in the valve plate.

A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

A planar micromechanical actuator suspended on opposing suspension zones including a neutral axis between the opposing suspension zones, first to fourth segments into which the planar micromechanical actuator is segmented between the opposing suspension zones, each including a first electrode and a second electrode which form a capacitor and are isolatedly affixed to each other at opposite ends of the respective segment along a direction between the opposing suspension zones so as to form a gap between the first and second electrode along a thickness direction, the gap being offset to the neutral axis along the thickness direction, and wherein the first to fourth segments are configured such that the planar micromechanical actuator deflects into the thickness direction by the first and fourth segment bending into the thickness direction and the second and third segments bending contrary to the thickness direction upon a voltage being applied to the first and second electrodes of the first to fourth segments.

An electronically commutated hydraulic machine is coupled to a drivetrain. Working chambers of the hydraulic machine are connected to low and high pressure manifold through electronically controlled valves. The phase of opening and closing of the valves has a default. In order to avoid cycle failure due to acceleration events, for example due to backlash in the drivetrain, the phase of opening or closing of the electronically controlled valves is temporarily advanced or retarded from the default timing.