US2982277A - Automotive device - Google Patents

Description

United States Patent r"ice AUroMo'rIvE DEVICE Claude H. May and Keith H. Rhodes, Racine, Wis., as-

signors to Walker Manufacturing Company, Racine, Wis., a corporation of Delaware Filed May 3, 1960, ser. No. 26,499 9 Claims. (Cl. 12s-139) It is often required-in pressurized liuid systems, for' example, in a fuel injection system for a conventional internal combustion engine, that the iluid capacity of the system be related, in some predeterminable manner, to fluid pressure in the system. Characteristically, such fluid systems have heretofore employed spring biased pistons,

or thellike, to vary the capacity of the system in response to system pressure. However, this expedient generally requires a fluid sealing lit betweenV thepiston and its supporting cylinder thereby increasing both the complexity and manufacturing cost of the system.

The present invention is directed to a constant stroke variable displacementfuel injector having a novel means for varying displacement in relation to pressure in the fuel system thereby to vary the quantity of fuel injected into a working cylinder of an internal combustion Vengine on each stroke of the fuel injector. v

Accordingly, one object of the present invention is an improved fuel injector for an internal combustion engine.

Another object is a fuel injector having a member that varies in displacement in accordance with fuel pressure in a fuelsupply system.

Another object is a variable displacement member for a fluid system that is compressible to a minimum displacement conditionat a controlled rate.

Another object is a variable displacementl member for a fluid system that is easily fabricated yet relatively impervious to wear due to compression thereof.

Other objects and advantages of the present invention will become apparent from the following description wherein'reference is made to the drawings in which:

Figure l is a sectional side elevation of a fuel Ainjector Fig. 2 is a fragmentary sectional view of the variable y example, a suitable aperture in the cylinder head of a conventional internal combustion engine (not shown).

An upper end portion 16 `of the housing 12 has an internally threaded portion 17 therein for the acceptance `of a .suitably threaded lower Yend portion 18 of aV valve housing 19. `The valve housing 19 extends upwardly from the housing 12 and has .a thr'e'adedbore 20 in an upper 2,982,277. Patented May 2, 1.961

end portion 21 thereof for the acceptance of a conventional conduit locking screw 22. The screw 22 has a. central bore 23 therein for the acceptance of a fuel supply tube 24 that runs from a fuel transfer pump (not shown). Fuel is conducted to the injector 11 through the conduit 24 under a predetermined pressure, variations in pressure effecting control of the quantity of fuel in jected on each stroke of the injector 11, in a manner to be described.

The valve housing 19 has a central bore 30 communicating with the threaded bore 20 therein for the passage of fuel downwardly into a check valve chamber 32. The bore 30 is normally closed by a check valve 34 that is biased against an annular frusto-conical valve seat 36 by a helical compression spring 38. The compression spring 38 is seated against an end face 39 of a counterbore 40 in a downwardly extending tubular shaft mem'- ber 42.

The shaft 42 has a threaded upper end portion 44 that is accepted in a suitably threaded bore 46 in the lower end portion 18 of the valve housing 19. A suitable seal;- ing washer50 is interposed between an upper end face 52 on the shaft 42 and an end face 54 of the bore 46 to effect a lluid seal therebetween. An axial bore 56 in the shaft 42 providesfor the conduction of fuel downwardly from the valve chamber 32 and the counterbore 40 therein into a fuel metering chamber 60.

The housing 12 has a transverse aperture 70 therein that communicates with a peripheral chamber 72 defined by an annular resilient boot 74. The boot 74 has a pair of axially spaced annular beads 76 and 78 thereon that are sealably engaged in complementary annular recesses 80 and S2 inthe valve housing 19 and housing 12,'respec`- tively. An aperture 84 in the boot 74 communicates with the chamber 72 and a nipple 86 that is connectible to a suitable conduit (not shown) for the conduction of leakage fuel to a fuel reservoir.

The housing 12 has a central bore '90 withinthe lower end 14 thereof that communicates with a coaxial a bore 92 of relatively larger internal diameter. The junction of the bores and 92 defines an annular transverse shoulder 94, that functions in a manner to be described.

A cylinder is reciprocable within the bores 90 and 92 and comprises an upper portion 101 and a lower portion 102 that are joined together as by complementary threaded portions 103 and 104, respectively. The upper portion`101 of the cylinder 100 has a pair of axially spaced annular peripheral flanges 105 and 106 for the support of a suitable sealing ring 107, for example an O-ring that is disposed between the flanges 105 and .V106 t0 effect a fluid seal between the cylinder 100 and the housf ing 12. A suitable gasket 10S is interposed between the ilange 106 and an uuper end face 109 of the lower cylinder portion 102 to effect a uid seal therebetween.

A helical compression spring 110 extends between a lower end face 1127on the valve housing 19 and an upper face 114 on the flange 105. The spring 110 normally biases the cylinder 100 downwardly with respect `to the housing 12, a transverse shoulder 116 on the lower end portion V102 thereof engaging the shoulder 94 on the housing 12 to define a'lowermost position for the cylinder 100 with respect thereto.

The shaft 42 extendsV downwardly through a central bore 120 in the upper end portion 101 of the cylinder 100, the cylinder 100 being slidable in telescoping relation V- longitudinally thereof within the housing 12.

vA lower end portion 124 .of the shaft 42 has a counterbore 126 ltherein which, in combination with a portion of the bore 120 inthe upper end portion 101 of the cylinder' 100, defines a section of the fuel metering chamber 60. The lower end portion 102 of the cylinder 100 has an upwardly extending threaded central bore 130 for the acceptance of a complementary threaded upper end portion Y 132 of a nozzle 134. A lower end face -136 of the nozzle 134 extends into a combustion chamber (not shown), and is therefore subject to fluid pressure within the working cylinder of an internal combustion engine. A suitable sealing washer 138 is interposed between the nozzle 134 and the lower end portion 102 of the cylinder 100- to eifect'a fluid seal therebetween.'

The nozzle 134 has a downwardly extending threaded central bore 140 for the acceptance of a suitably threaded lower end portion 142 of a nozzle spring retainer 144. The nozzle spring retainer 144 has aradial flange 146 with a counterbore 148 therein for the acceptance of a plurality of nozzle springs 150. Thenozzle` springs .150 comprise a plurality of dished Belleville'was'hers that are suitably stacked tofform a compression spring. The Belleville washers 150 extend between an end'face 152 of the counterbore 14S and a spring retainerv 154 that is seated in a suitable groove 156 in a valve '160'.

The valve 160 extends downwardly through central bores 162 and 164 in the spring retainer 144 and nozzle 134, respectively. The valve 160 has a truncated upwardly convergent conical lower end portion 170 that is normally seated in a complementary upwardly convergent valve seat 172 in the nozzle 134. The valve 160 is normally biased to the closed position, wherein the end portion 170 thereof is seated against the seat 172, by the Belleville washers 150. An upper end face 174 of the valve 160 extends into and communicates with the interior of the fuel metering chamber 60 thereby rendering the valve 160 responsive to fuel pressure within the fuel metering chamber 60.

-In accordance with the present invention, fuel metering is accomplished by the variable displacement member which is disposed within the fuel metering charnber 60. The member 10 is preferably made from resilient material, for example, a plastic material sold under the trade name Durometer, and comprises complementary radially spaced oppositely opening annular members 202 and 2 04. The radially inwardly opening member 202 comprises an axially extending side wall 203 having a pair of radially inwardly extending end flanges 206 and 208 that are engageable, in overlapping relationship with a pair of radially outwardly extending llanges 210 and 212, respectively, on the inner member 204. The inner member 204 has an axially extending annular wall portion 213. The flanges 206 and 208 are sealed with respect towtheir complementary flanges 210 and 212, respectively, as by vulcanizing, thereby to define an annular sealed chamber 220.

The side walls 203 and 213 are normally maintained in the axially extended condition to maximize the volume ofthe chamber 220. This is accomplished by a plurality of dished Belleville washers 224, 226 and 22S that are stacked in reversed relationship concentrically with respect to an annular spring support member 230.

' Thespring support member 230 is disposed within the chamber 220 for the positioning and support of the springs 224, 226 and 228 and comprises an axially extending bushing portion 232 having a centrally located radially outwardly extending flange 234 thereon that, in conjunction with the bushing 232, defines a pair of axially spaced shoulders 236 and 238 for the support of the springs 226 and 228, respectively.

lA pair of annular pressure plates 240 and 242 are disposed in axially spaced relationship against the radially extending anges 206-210 and 208-212, respectively, to evenly distribute and transmit the normal axial bias of the springs 224, 226 and 228 to the anges 206-210 and 20S- 212. A

The members 240 and 242 have axially extending annular flanges 244 and 246 on the outer peripheral edge thereof that are engageable upon axial compression of the member 10 to define an index or minimum volume condition thereof. It is to be noted that the inner end 4y Y portions 250 and 252 of the members 240 and 242, respectively, are engageable with the bushing portion 232 of the annular member 230 to thereby support the members 240 and 242 at two radially spaced points upon compression of the member 10 to its minimum volume condition.

Upon the occurrence of suitable conditions, to be described, during each cycle of ak pistonlnot shown), fuel pressure within the the conduit 24 dislodges the inlet check valve 34 from its seat 36, thereby prassingfuel downwardly into the metering chamber 6,0. The fuel exerts a pressure against the exterior of the member y10 thereby compressing the member 10 to a volume directly related to the pressure of the fuel. When the external pressure of the fuel on the member 10 isl balanced by outward bias of the springs 224, 226 and 228, the member 10 is stabilized at a metering volume. Obviously, higher fuel pressures compress the member 10 to relatively smaller volumes and displacements therebyl enlarging the fuel capacity of the metering chamber 60.

vAs the piston of the engine (not shown) progresses on a compression stroke, compression pressure within the working cylinder (not shown) is exerted on the `lower end face 136 of the nozzle 134 tending to drive the nozzle 134 and cylinder 100 upwardly with respect to the housing 12 against the downward bias of the spring l110. This upward movement of the nozzle 134 and cylinder 100 with respect to the shaft 42 tends to increase the fuel pressure within the metering chamber 60, thus compressing the member 10 to its minimum volume condition wherein the flanges 244 and 246 abut o ne another and the end portions 250 and 252 of the pressure plates 240 and 242, respectively, engage the spring support 230. Because the fuel within the metering chamber 60 is relatively incompressible, the volume of the metering chamber 60 remains relatively constant from the time that the inlet valve 34 closes and the cylinder 100 commences its upward movement until the member 10 is compressed to its minimum volume condition.

As engine compression pressure continues to rise in the'working cylinder (not shown) the fuel pressure in the kmetering chamber 60 continues to rise until the pressure, effective on'the upper end face 174 of the valve 160 is suicient to bias the valve 160 downwardly with respect to its seat 172 in the nozzle 134 whereupon fuel is forced past the conical portion 170 of the valve 160 into theworking cylinder of the engine (not shown). When the valve 160 opens, the nozzle 134 and cylinder y1.00 move upwardly with respect to the shaft 42 until the cylinder strikes its datum point against the upper end 44 of the shaft 42. When this condition obtains, the volume of the metering chamber 60 is minimized, and the injection of fuel is terminated.

It will be noted that the commencement of injection can be controlled bythe preloading of the nozzle springs as related to the preloading of the springs 224, 226 and 228 of the member 10.

As pressure in the working cylinder (not shown) decreases, due to retraction of the piston on the power stroke, the cylinder 100 is biased downwardly by the spring 110. When the pressure of the fuel remaining in the metering chamber 60 is lowered sufficiently to create a pressure differential on opposite sides of the valve 34, fuel ows past the valve 34 into the metering chamber 60 and compresses the member 10 until a pressure balance occurs between the outward bias of the springs 224, 226 and 228 and the pressure of the fuel on the exterior sur- -faces of the member 10. The volume of the member 10 at which the balance condition occurs is therefore determined by the pressure of the fuel in the conduit 24. In this manner the capacity of the metering chamber 60 and therefore the quantity of f uel injected by the injector 11 on'each stroke thereof` is relatively easily regulated by controlling the upstream pressure of the fuel as by mnventenal means (nat shown).

Referring to Fig. 4, a modified compressible member 400 comprises an annular chamber 402 defined by a cupshaped member 404 having a radially extending annular top wall 405 and a pair of radially spaced annular side walls 406 and 408. The outer side wall 408 has a radially outwardly extending peripheral fiange 410 thereon and the inner side wall 406 has a radially extending center portion 412 that are bonded to a substantially fiat bottom member 414, by any suitable means.

The compressible member 40@ is normally expanded axially, thereby to maximize the volume of the chamber 402, by a plurality of dished Belleville washers, 424, 42e and 428 that are stacked in opposed relationship coaxially about an annular spring support member 436. The spring support member 430 comprises an axially extending bushing portion 432 having a centrally located radially outwardly extending flange 434 thereon that defines a pair of axially spaced shoulders 436 and 438 for the support of the springs 424 and 426, respectively.

A pair of annular pressures plates 440 and 442 are disposed in axially spaced relationship against the top wall 405 and bottom plate 414 of the member 400 to evenly distribute and transmit the iiuid pressure within the chamber 60 to the springs 424, 426 and 428. The members 440 and 442 have axially extending peripheral iianges 444 and 446 on the outer peripheral edges thereof, respectively, that are engageable upon axial movement of the members 440 and 442 toward one another to define the index or minimum volume position of thev volume absorber 400. The inner end portions 450 and 452 of the members 440 and 447, respectively, are engageable with the bushing portion 432 of the annular spring support 430 to thereby support the members 440 and 442 at two radially spaced points upon compression of the member 400 to its minimum volume condition. The variable displacement member functions in the manner described hereinbefore with respect to the member 10.

From the foregoing description it should be obvious that the compressible member described hereinbefore has utility in dissipating shock in fluid systems as well as absorbing fluid capacity therein and therefore has utility in fluid systems other than the system disclosed.

It should also be apparent that the fuel injector 11 wherein the variable displacement members have particular utility to effect metering, presents a material step forward in the fuel injector art.

While it will be apparent that the embodiments of the invention herein disclosed are well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A fuel injector for an internal combustion engine comprising means defining a fuel metering chamber, and compressible means within said chamber for. varying the fuel capacity thereof in response to fuel pressure therein comprising a sealed hollow member of deformable material, resilient means within said member for normally biasing said member to a first volume, and means within said member establishing a predetermined minimum volume for said member.

2. A fuel injector for an internal combustion engine comprising relatively movable cylinder and shaft defining a fuel metering chamber, and compressible means within said chamber for maintaining the fuel capacity thereof constant through finite relative movement between said cylinder and shaft comprising a sealed hollow member of deformable material, spring means within said member for normally biasing said member to a first volume, and

Ameans within said member establishing a predetermined minimum volume for said member.

3 A fuel injector for an internal combustion engine comprising a housing, a cylinder movable within said housing, a shaft fixedly supported by said housing and slidable within said cylinder, said shaft and cylinder defining a portion of a fuel metering chamber, and compressible means within said chamber for Varying the fuel capacity thereof in response to inlet fuel pressure into said chamber comprising a sealed hollow member of deformable material, spring means within said member for normally biasing said member to a first volume, and means within said member establishing a predetermined minimum volume therefor.

4. A fiel injector for an internal combustion engine comprising means defining a fuel metering chamber, a fuel inlet valve into said metering chamber, and compres- -sible means within said chamber for varying the fuel capacity thereof in response to the fuel pressure in said chamber when said inlet Valve is in the open condition comprising a sealed hollow member of deformable material, means within said member for normally biasing said member to a first volume, and means within said member establishing a predetermined minimum Volume of said member.

5. A fuel injector for an internal combustion engine comprising means defining a fuel metering chamber, and compressible means within said chamber for varying the fuel capacity thereof in response to the fuel pressure therein comprising a sealed annular member of deformable material, an annular spring support within said member, a plurality of dished washers supported by said spring support for biasing said member to a first volume and means within said member engageable with said spring support for establishing a predetermined minimum volume for said member.

6. A compressible member for varying the iiuid capacity of a system in relation to fluid pressure therein comprising a sealed annular member of deformable material, an

' annular spring support within said member, a plurality of dished washers supported by said spring support for biasing said member to a first volume, and means within said member engageable with said spring support for establishing a predetermined minimum volume for said member.

7. A compressible member for Varying the fluid capacity of a system in relation to fluid pressure therein comprising a sealed annular member of deformable material, a spring support within said member having a pair of annular axially spaced shoulders for the support of a plurality of axially spaced oppositely directed dished washers for biasing said member of a first volume, and a pair of annular washers engageable with each other and said spring support for establishing a predetermined minimum volume for said member.

8. A compressible member for varying the fluid capacity of a system in relation to fluid pressure therein comprising a sealed member of deformable material defining an annular chamber, a pair of annular washers within said chamber in juxtaposed relation against opposite transverse end walls thereof, an annular spring support within said member, a plurality of dished washers extending between said washers and said spring support for biasing said member to a first volume, and a pair of peripheral axially extending anges on said washers engageable upon contraction of said member for establishing a predetermined minimum volume for said member.

9. A compressible member for varying the uid capacity of a system in relation to fluid pressure therein comprising a sealed hollow member of deformable ma- `terial, resilient means within said member for normally biasing said member to a rst volume, and means within said member establishing a predetermined minimum v01- ume for said member.

No references cited.

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