Electromagnetic fuel injector for internal combustion engines

Abstract

The injector (5) has a hollow body (6) having an injection nozzle (8) controlled by a control rod (12) movable axially by a metering valve (23) controlled by an armature (43) of an electromagnet (42). The metering valve (23) has a control chamber (28) having a pressurized-fuel inlet conduit (33) and a surplus fuel drain conduit (34). To reduce the length of the injector (5), the inlet conduit (33) is coaxial with the rod (12) and communicates with a coaxial cavity (19) fed with fuel from the top; the drain conduit (34) is radial with respect to the axis of the rod (12), and the armature (43) is also movable radially; the armature (43) and the electromagnet (42) are housed in an arm (21) which is also radial with respect to the axis of the rod (12); and the cavity (19) has a conical portion (91) in which a bulb-shaped portion (88) of a fitting (87) of a supply conduit (82) is fitted by means of a ring nut (93).

Description

technical field [0001] The invention relates to an electromagnetic fuel injector for an internal combustion engine. Background technique [0002] Numerous forms of electromagnetic fuel injectors are known, one of which has a hollow body with an injection nozzle which can be opened and closed by a rod which moves axially within the hollow body. The rod is in turn controlled by a metering valve controlled by an axially movable armature and comprising a control chamber with a radial inlet and an axial return. The length of this type of injector cannot be changed, so the cylinder head needs to have a suitable height. [0003] On modern engines the injectors are usually connected to a common supply line (rail) which is supplied with high pressure fuel by a pump. With known injectors of the type described above, the common supply pipe must be placed in a transverse position with respect to the injector body and is therefore difficult to arrange and connect. [0004] US 4709679 ...

AI Technical Summary

Problems solved by technology

With known injectors of the type described above, the common supply pipe must be placed in a transverse position with respect to the injector body, making it difficult to arrange and connect

[0004] US 4709679 discloses an electromagnetic fuel injector in which, when the return pipe is opened, the end face of the control rod defining the control chamber closes the input pipe, whereby when the return pipe is closed again, the high pressure fuel in the control chamber is restored some difficulties or delays may occur when

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