Valve for dosing liquids or gases

A valve for dosing liquids or gases, particularly an injection valve for fuel injection systems of internal combustion engines, such as directly injecting diesel motors and the like, the valve comprising a valve housing having a dosing opening;

• a valve needle which controls said dosing opening;
• a valve closing spring cooperating with said valve needle and withdrawing the latter to a closing position in which said valve needle closes said dosing opening;
• a piezoelectric adjusting member having a piezo stack which is longitudinally changeable under the action of a control voltage, said piezo stack having two ends and being connected by its one end with said valve needle;
• and abutment connected with the other end of said piezo stack, said abutment being displacable in an axial direction of said piezo stack and formed so that during a longitudinal change of the piezo stack caused by the control voltage it is spatially fixed relative to said housing, said abutment being formed as an electromagnetic arresting arrangement which is actively switched on at least during a time of opening of said valve, said electromagnetic arresting arrangement including a bar-shaped armature which is fixedly connected with said piezo stack, an exciting coil which surrounds said armature and has an axial length substantially smaller than that of said armature, and a yoke which is fixed to said housing and received said exciting coil, said yoke surrounding said armature so as to leave a ring-shaped air gap therebetween and being subdivided into a plurality of yoke portions which abut one another in a longitudinal direction and allows supporting against said armature when current is applied to said exciting coil.

A valve for dosing liquids or gases, particularly an injection valve for fuel injection systems of internal combustion engines, such as directly injecting diesel motors and the like, the valve comprising a valve housing having a dosing opening;

• a valve needle which controls said dosing opening;
• a valve closing spring cooperating with said valve needle and withdrawing the latter to a closing position in which said valve needle closes said dosing opening;
• a piezoelectric adjusting member having a piezo stack which is longitudinally changeable under the action of a control voltage, said piezo stack having two ends and being connected by its one end with said valve needle;
• an abutment connected with the other end of said piezo stack, said abutment being displaced in an axial direction of said piezo stack and formed so that during a longitudinal change of the piezo stack caused by the control voltage it is spatially fixed relative to said housing, said abutment being provided with an electromagnetic arresting arrangement having at least one moveable part which is arranged between said abutment and a fix part of said housing and held in permanent contact to said fix part by means of a spring, said moveable part being rigidly coupled to said abutment and said fix part by means of an electrically controlled force at least during a time of opening of said valve, and released after closure of said valve.