Pilot controlled solenoid valve

Abstract

A pilot controlled solenoid valve () includes a housing () having an inlet () and an outlet (), a valve seat () between inlet () and outlet (), a valve element () cooperating with the valve seat (), and a solenoid arrangement () having a coil () and a moveable armature (), wherein the valve element () is arranged between an inlet chamber () connected to the inlet () and a pilot pressure chamber () and includes a pilot channel () extending from the pilot pressure chamber () to the outlet (), wherein the moveable armature () opens and closes an opening of the pilot channel () into the pilot pressure chamber () depending on magnetic forces produced by the coil (). In such a valve noise should be kept small. To this end, pressure decreasing means are provided decreasing a pressure in the pilot pressure chamber () below a pressure downstream the valve seat () when the valve element () is lifted off from the valve seat ()), wherein the pressure decreasing means are driven by a flow of a fluid from the inlet () to the outlet () controlled by the valve and are in form of a flow restriction () in fluid connection with the pilot pressure chamber (), wherein the flow restriction () is provided in addition to a flow restriction formed between valve element () and valve seat (), wherein the flow restriction () includes a protrusion () of the valve element () protruding into the valve seat () when the valve element () is lifted off the valve seat () and a ring gap between the protrusion () and an inner wall of the outlet () is smaller than a distance between valve element () and valve seat () in a fully open condition of the valve, so that the area through which the fluid controlled by the valve () can pass is the smallest one on the way from the inlet () to the outlet ().