US 4,232,830 A · Electromagnetic fuel injector

Abstract

A high flow rate electromagnetic injector valve with a rapid response time is disclosed for utilization in a single point fuel injection system. Centrally bored end caps are fixed at the front and rear ends of a tubular injector body and a coil wound on a bobbin is disposed inside the body chamber between the end caps. The front end cap receives within its bore a valve assembly including a valve housing and a needle valve with attached armature reciprocally movable against a valve seat to obturate a metering orifice in the valve housing. The valve housing contains fuel inlets for the pressurized entry of fuel into the injector and the needle valve is ported to provide fluid communication to the armature to relieve pressure build-up. The rear end cap mounts within its bore a core member acting as a stator which extends through a central bobbin bore to form a controllable air gap adjacent the armature: the core member further contains internally an adjustment screw and ball member. The ball member and adjustment screw cooperate with a recessed closure spring positioned substantially within the armature to controllably bias the needle valve against the valve seat. Because of its recessed position, the force of the closure spring is applied substantially along the central axis of the injector valve and the ball member prevents torsional windup forces from being generated by the spring. O-ring seals for the bobbin bore are provided in compression between recesses in the bobbin and the slower contracting material of the front end cap and core member to produce extended cold temperature operation.

Claims16

Dependent claims

An electromagnetic fuel injector valve comprising:

a tubular injector body forming an inner chamber between its ends with a centrally bored front end cap fixed to one end and a centrally bored rear end cap fixed to the other;
a bobbin, wound with a coil, disposed in said inner chamber between said end caps and having a longitudinal bobbin bore substantially aligned with the central bore of each end cap;
means for electrically connecting said coil to a source of an injection signal;
a valve assembly including a valve housing and needle valve, said needle valve reciprocally mounted within a centrally located valve housing bore which terminates in a metering orifice, said needle valve operable to open and close the metering orifice, said front end cap bore being singly stepped to form a shoulder that separates said front end cap bore into a mounting bore and an armature guide bore, said valve housing positioned in the mounting bore to where it abuts said shoulder and said valve needle extending into the armature bore where it is attached to an armature movable in said armature guide bore;
first means for communicating fuel from a pressurized source to said valve housing bore;
a core member mounted through said rear end cap bore that extends into said bobbin bore to where it is adjacent said armature and forms an air gap therebetween;
and
a closure spring under compression disposed such that a force is applied to the needle valve to cause a closing of the metering orifice;
wherein said coil sets up a magnetic force across said air gap when said injection signal is present that overcomes the closure spring force to open the metering orifice by lifting the armature and valve needle to where it abuts said core member.

6 more elements

Dependencies are inferred from the claim text.

Electromagnetic fuel injector

Life of this patent

Electromagnetic fuel injector

Life of this patent

Abstract

Claims16