Impact or ram-effect type electro-magnetic valve for automobile fuel injection system

摘要

The valve has a fuel input (3) and output (4). It houses an electro-magnetic winding (5) associated with a magnetic piece (6) and a plunger (7) having aligned contact surfaces (6a,7b). The plunger is connected to means (8) which close or open the output of the body (2) when the plunger is displaced by the magnetic piece and it comes into contact with the contact surface (6a) of the latter. At least one of the contact surfaces of the piece and/or the plunger include projecting and hollow parts designed so as to reduce the surface areas which press against each other, when the plunger is in position for opening the valves body. The valves supply control means (5a) for the electro-magnet (5) is designed to apply a current (I) having a feeding phase (A) and a maintaining phase (M). The current at the end of the feeding phase has a slope (A2) which is reduced with respect to that at (A1) so as to reduce the impact of the plunger on the magnetic piece when opening the valves output and thus reduce the risk of wear on these pieces.