초록 ▼

The invention relates to a control unit (4) for controlling the pressure buildup in a pump unit (2), with a control valve (5) and a valve actuation unit (6) connected to it, wherein the control valve (5) is embodied as an I-valve that opens inward in the flow direction, which has a valve body (11) t

The invention relates to a control unit (4) for controlling the pressure buildup in a pump unit (2), with a control valve (5) and a valve actuation unit (6) connected to it, wherein the control valve (5) is embodied as an I-valve that opens inward in the flow direction, which has a valve body (11) that is supported so that it can move axially in a housing (12) of the control unit (4) and rests against a valve seat (13) of the control valve (5) from the inside when the control valve (5) is closed. In order to produce a control unit (4) whose control valve (5) requires lower valve actuation forces and has short switching times, the invention proposes a control unit (4) which is characterized by means of an axially effective surface of the valve body (11) which surface is embodied in such a way that the forces, which act on the valve body (11) when the control valve (5) is closed and are due to the pressure present in the pump unit (2), cancel each other out.

대표청구항 ▼

1. A control unit (4) for controlling a pressure buildup in a pump unit (2) of a fuel delivery system, the pump unit (2) comprising a control valve (5) and a valve actuation unit (6) connected to the control valve (5), the control valve (5) has an inlet (26a) and an outlet (26b) wherein fuel flows t

1. A control unit (4) for controlling a pressure buildup in a pump unit (2) of a fuel delivery system, the pump unit (2) comprising a control valve (5) and a valve actuation unit (6) connected to the control valve (5), the control valve (5) has an inlet (26a) and an outlet (26b) wherein fuel flows through the control valve (5) in a direction from the inlet (26a) to the outlet (26b) when the control valve (5) is open, the control valve (5) has a valve body (11) that is supported so that the valve body (11) moves axially in a housing (12) of the control unit (4) and rests against a valve seat (13) of the control valve (5) when the control valve (5) is closed, the control valve (5) opens by movement of the valve body (11) in a direction opposite to the direction of fuel flow through the control valve (5), wherein axially effective surfaces (11a, 11b) of the valve body (11) are embodied in such a way that, when the control valve (5) is closed, applied forces, which act on the axially effective surfaces (11a, 11b) of the valve body (11) due to pressure present in the pump unit (2) cancel each other out, the valve body (11) has a circular cross-section and on one side has a first guide element (14) which is supported so that the valve body (11) can move axially in the housing (12), the valve seat (13) has an annular course, and an outer diameter of the first guide element (14) is equal to an outer diameter of the valve seat (13), the valve body (11) on a second side has a second guide element (15) which is supported so that the valve body (11) can move axially in the housing (12), wherein the valve actuation unit (6) is a piezoelectric actuator, the housing (12) is constructed of a first housing part (12a) and a second housing part (12b), the first housing part (12a) having a first axial bore (12c) for receiving the first guide element (14) and a second bore (12d) which is coaxial to the first axial bore (12c), has a larger diameter, and is positioned with respect to the first bore (12c) generally in the direction of fuel flow through the control valve (5), wherein the inlet (26a) leads into the second bore (12d), the second housing part (12b) is disposed in the second bore (12d) with an end face of the second housing part (12b) spaced apart from a bottom of the second bore (12d), and the valve seat (13) is embodied on said end face of the second housing part (12b), the two axially effective surfaces (11a, 11b) are formed on an enlarged diameter portion of valve body (11), said enlarged diameter portion having a diameter (d2) which is greater than the diameter (d1) of the first guide element (14), and said enlarged diameter portion being movable within the second bore (12d) in a space defined by the bottom of the second bore and the valve seat (13) on the end face of the second housing part. 2. A control unit (4) to claim 1, in which the second housing part (12b) is press-fitted or shrink-fitted into the second bore (12d). 3. A control unit (4) according to claim 1, in which the second housing part (12b) is embodied as a bushing, which has a third bore (12e) for receiving the second guide element (15). 4. A control unit (4) according to claim 1, in which a small amount of play is embodied between the first guide element (14) and the first bore (12c) and a larger amount of play is embodied between the second guide element (15) and the third bore (12e). 5. A control unit (4) according to claim 4, in which a play of approximately 2 to 4×10-6m is embodied between the first guide element (14) and the first bore (12c) and a play of approximately 8 to 10×10-6m is embodied between the second guide element (15) and the third bore (12e).