US2392474A - Fuel injector - Google Patents

Description

Patented Jan, 8, 1946 FUEL mmc'ron l' Harry F. Haines, Canton, Ohio, assigner to .The

Timken RollerBeai-ing Company, Canton, Ohio, a corporation of Ohio Application January 31, 1944, serial No. 529,567

Claims.

This invention relates principally to fuel injectors for compression ignition engines, and more particularly to fuel injectors of the type having a valve that is opened hydraulically by the fuel pressure. The invention has for its principal object to devise a simple and economical fuel injector of the above type that will provide a small quantity of finely atomized fuel at the start of i injection, followed by delivery of the major part of the fuel in increasing or decreasing quantity, depending on the injection characteristic desired. The invention consists in the fuel injector and in the construction, combinations and arrangements of parts hereinafter described and claimed.

In the accompanying drawing, which forms4 part of this specification and wherein like symbols refer to like parts wherever they occur,

the fuel in the annular fuel chamber 4 acts on the conical portion 8 'of the plunger I above the valve seat I and forces said plunger upwardly, thereby lifting said conical portion off said valve seat and permitting flow of the fuel into the -chamber I0 and the escape of a small quantity of well atomized fuel through the primary annular yfuel discharge orifice 9. The fuel pressure then acts'V on the entire conical portion 8 of the valve plunger I to fully open the valve without increasing the quantity of fuel discharge through the annular primary fuel discharge orifice 9.

Fig. 1 is a central longitudinal sectional view Figs. 3 and 4 are views similar to Fig. 2, sho

ing two modified forms of the invention.

My fuel injector comprises a cylindrical plunger that is reciprocable in an axial bore provided therefor in a cylindrical nozzle member 2 and terminates at its lower end in a reduced pin or pintle portion 3 that normally projects beyond the lower or discharge end of said nozzle member. The axial bore of the nozzle member 2 has an annular groove therein that cooperates with 'the plunger I to form an annular chamber 4, which is supplied with fuel under pressure through one or more fuel inlet passageways that lead downwardly from an annular fuel inlet groove 6 in the upper or inlet end ofsaid nozzle member and opens into said chamber through the side thereof.

'I'he portion of the axial 'bore of the nozzle member 2 below the fuel chamber 4 therein is tapered inwardly and downwardly to provide a conical valve seat 1. The plunger has a portion 8 that tapers downwardly from a point above the bottom of the chamber 4 to the pin 3 located therebelow and forms aconical valve element for cooperation with the conical valve seat I located between said bottom of said chamber and the lower or discharge end of the plunger supporting bore. The outer or discharge end of the plunger supporting bore of the nozzle 2 is further reduced to form with said plunger an annular primary fuel discharge orifice 3 and an annular fuel chamber Il) between the valve seat 8 and said discharge orice.

By thearrangement described, the pressure of -ing the opening lift of the valve.

The primary discharge of 'fuel through the nardischarge of the major part of the fuel through a separate main fuel discharge passageway in the pintle end 3 of the plunger I. As shown in Figs. l and 2, this main fuel discharge passageway comprises a diametral cross bore or passageway I I in the pin 3 and an axial discharge passageway I2 that leads downwardly from said diametral passageway and opens through'the outer or lower end face of said pin. The location of the diametral passageway I I is such that it is not brought into direct communication with the fuel chamber II) until after the tapered portion 8 of the plunger I is lifted oil the valve seat 1 and a small quantity of finely divided fuel has escaped through the primary discharge orifice 9. After this primary discharge of the fuel, continued opening movement of the plunger I brings the diametral passageway II therein into direct communication with the chamber III, thus permitting the discharge of the major portion of the fuel injection a through the axial discharge passageway I2.

. As shown in Fig., 2, the axial fuel discharge passageway I2 in the pin I may be counterbored, as at I3, to any desired diameter and depth to vary the shape andl power of penetration of the main fuel jet. The cross-sectional shape of the diametral fuel passageway I I may be changed to vary the quantity of the main fuel injection dur- Thus, the passageway may be of circ-ular cross-section, as shown in Fig. 2, or with downwardly diverging side walls Ila, 'asfshown in Fig. 3, whereby the cross-section of said passageway is opened gradually as it ymoves upwardly across the control edge IIla formed'by the bottom of the fuel chamber I0 and the quantity of fuel discharged `of the main fuel injection is a maximum at rst, followed by a gradual decrease in fuel delivery formance. valve brings the main fuel discharge passage- ,as the valve opens.

as the valve completes its opening movement.

By the arrangement described, the annular fuel must lead the main injection for best; per- Continued opening movement'l of the way II, I2 in the pin or pintle 3 of the plunger I `into communication with the annular fuel cham.- ber I0, whereby the major portion of the fuel is discharged through the outlet end I2 of said axial discharge passageway. This discharge of the main or major portion of the fuel injection `through the axial discharge passageway l2 may `be controlled, as shown in Fig. 3, to provide a gradual increase in the quantity of fuel delivery 3as the valve opens, or, as shown in Fig. 4, to `provide a decrease in the fuel quantity delivery As shown in Fig. 2, thel lmouth I3 of the axial discharge passageway I2 may be shaped to vary the spray characteristics `of the main fuel jet.

What I claim is: l. A fuel injector comprising a nozzle having `a bore opening through the outer end of said nozzle, an inwardly facing valve seat in said bore adjacent to the outer end thereof and a `fuel supply passageway opening into said bore inwardly of said valve seat, and a plunger reiciprocable in said b'ore and having a valve element cooperating with said valve seat and portions cooperating with said bore to form therewith an annular fuel discharge orifice at the router end thereof, and an annular fuel chamber extending from said valve seat to said annular discharge orifice and in continuous communication'with the latter, said plunger having a fuel discharge passageway with an inlet end located in the side face of said plunger and a discharge end opening through the outer end thereof, said inlet end of said discharge passageway opening into said annular discharge' orice in the closed position of said valve andbeing movable inwardly of said annular discharge orifice into direct communication with said annular fuel chamber after an initial discharge of fuel through said annular discharge, orifice at the beginning of the valve opening stroke of said plunger.

2. The combination as set forth in claim 1, wherein the width of said inlet end of said discharge passageway is varied in the direction of the plunger axis to vary the quantity of. fuel discharged through said dischargepassageway after such initial discharge of fuel through said annular discharge orifice.

3. 'Ihe combination as set forth in claim l, wherein said inlet end of said discharge passageway increases in width from the inner towards the outer end of s aid plunger to increase the quantity of fuel dischargedfrom said discharge passageway after such initial discharge of fuel through said annular discharge orifice.

4. The combination as set forth in claim 1, wherein said inlet end of said discharge passage- Way decreases in width from the inner towards the outer end of said plunger to decrease the quantity of fuel delivered from saidA discharge passageway alter such initial discharge of fuel through said annular discharge orifice.

5. The'combination as set forth in claim l, in which said discharge passageway is enlarged at the discharge end thereof.

HARRY F. H AINES.

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