Patent ID: 6425539
Filing Date: 2002-07-30
Classification: F02M,F04B

Abstract:
A control unit for controlling a pressure buildup by a pump unit in a fuel injection system, in which the control unit includes a control valve (1) and a valve actuation unit connected to the control valve (1) in order to selectively actuate the control valve (1), the control valve (1) has a first valve body (3) disposed between an inlet (8) and an outlet (9) of the control valve (1) and supported within a housing (2) of the control unit so that the first valve body moves axially in the housing (2), the first valve body (3) controls a flow through the control valve (1) in a direction (14) from the inlet (8) to the outlet (9), the control valve (1) is embodied as an inlet valve with the first valve body (3) that rests on a valve seat (4) of the control valve (1) from an inside of the control valve (1) when the control valve (1) is closed to prevent any flow through the control valve (1) and opens in a direction approximately opposite to the flow direction (14), the control valve (1) further has a throttle device (5) disposed between the inlet (8) and the outlet (9) and making part of the first valve body (3), the throttle device (5) throttles the flow through the control valve (1) when the control valve (1) is opened by a small stroke (ssmall) and allows an unrestricted flow through the control valve (1) when the first valve body (3) is opened beyond the small stroke (ssmall), the throttle device (5) includes a second valve body (6) which is disposed between the first valve body (3) and the outlet (9), the second valve body (6) has at least one throttle bore (7) which communicates with the inlet (8) and the outlet (9) when the control valve (1) is open by the small stroke (ssmall) and allows an unrestricted air flow through the control valve (1) when the first valve body (3) is opened beyond the small stroke (ssmall), the second valve body (6) is supported within the first valve body (3) so that the second valve body (6) moves axially in the first valve body (3) and the second valve body (6) rests on a second valve seat (10) of the control valve (1) from the inside of the control valve (1) as long as the stroke (s) by which the first valve body (3) is opened does not go beyond the small stroke (ssmall).