US3297261A

US3297261A - Fuel injection nozzle valve

Info

Publication number: US3297261A
Application number: US415390A
Authority: US
Inventors: Richard P Heintz
Original assignee: Pneumo Dynamics Corp
Current assignee: Pneumo Dynamics Corp
Priority date: 1964-12-02
Filing date: 1964-12-02
Publication date: 1967-01-10
Anticipated expiration: 1984-01-10
Also published as: GB1055010A

Description

Jan. 10, 1967 R. P. HEINTZ FUEL INJECTION NOZZLE VALVE Filed Deo. 2, 1964 2 Sheets-Sheet 1 PIM... n om wif om M EE NQ N ATTORNEY Jan. 10,` 1967 R, P, HElNTz 3,297,261

FUEL INJECTION NOZZLE VALVE Filed Deo. a, 1964 2 sneetsheet 2 FIG. 2

1 N VENTOR.

RICHARD P. HEINTZ BY W www A T TORNE Y United States Patent O 3,297,261 FUEL INJECTION NOZZLE VALVE Richard P. Heintz, Kalamazoo, Mich., assigner to Pneumo Dynamics Corporation, Cleveland, Ohio, a corporation of Delaware Filed Dec. 2, 1964, Ser. No. 415,390 11 Claims. (Cl. 239-534) The present invention relates to an improved fuel injection nozzle valve for injecting fuel into the combustion chamber of internal combustion engines and the like.

Present fuel injection nozzle valves of the type here concerned are generally characterized by the presence of relatively slidable or movable valve components which require manufacturing to rather close tolerances to satisfactorily provide controlled movement between such components. The diasdvantages inherent in present such valve constructions are well understood by those skilled in the art. Not only are manufacturing costs understandably relatively high, but valve malfunction frequently occurs as a result of improper seating of the relatively movable components due, by way of example, to contaminants in the fuel delivered to the valve interior. Present injector valves are further characterized by relative inilexibility in use in that the injector openings are normally formed in the valve housing to provide a predetermined discharge path of the injected fuel to afford optimum engine operation. Thus, to permit use of the valve with the cylinder heads of different engines, the same discharge opening arrangement must be satisfactory for such different engines, and if not, a different valve must be employed.

An object of the present invention is to provide a fuel injection nozzle valve which is not dependent upon close tolerances in the relatively movable components thereof thereby substantially reducing the cost of manufacture of the valve as well as reducing the likelihood of malfunctioning.

A further object of the present invention is to provide a fuel injection nozzle valve having an improved, simplied means for supplying fuel to the valve interior.

A more specific object of the present invention is to provide a novel flexible sleeve enveloping the valve poppet of the nozzle valve, the pressure of the fuel delivered to the valve resiliently expanding such sleeve to permit the fuel to enter the valve accumulating chamber, with the pressure in the latter during injection tightly closing the flexible sleeve around the poppet to prevent leakage from the accumulator chamber to the fuel supply line.

Yet another object of the invention is to provide a fuel injection valve adapted to accommodate fuel supply lines of varying lengths thereby to facilitate timing of the fuel system.

A still further object of the present invention is to provide a fuel injection valve having a replaceable nozzle to accommodate mounting of the valve for use with variously designed engines.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the yfeatures hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth -in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a longitudinal cross-sectional view of the fuel injection nozzle valve of the present invention;

FIG. 2 is an enlarged fragmentary view of a portion of FIG. l, more :clearly showing the removable nozzle of the injection valve;

FIG. 3 is a sectional view taken on line 3 3 of FIG. 2; and

FIG. 4 is a slightly modified form of fuel injection nozzle valve.

Referring now in detail to the drawings, wherein like parts are designated by like reference numerals, and initially to FIG. 1, the fuel injection nozzle valve of the present invention is generally indicated at 10 and is adapt-ed to be mounted to the cylinder head of an internal combustion engine in any suitable manner, such as, for example, by means of a mounting flange 12. The latter is formed with a plurality of openings commonly desi.,- nated at 14 for such mounting and it will be understood that the forward or nozzle end of the valve extends into the combustion chamber for supplying fuel thereto, all in a well-known manner.

The valve 10 comprises an elongated valve body 16 which is formed with a shoulder 1S relatively adjacent the outer ends thereof for receiving the mounting flange 12, with the extreme outer end of the body being threaded to receive a jam nut 20 for rigidly securing the valve body to the mounting flange. The valve housing 16 further includes a reduced nozzle end portion 22 which is adapted to receive a replaceable nozzle generally indicated at 24, the details of which will be hereinafter described in detail when particular reference is made to FIGS. 2 and 3. A shielding jacket 26, shown in dashed lines in FIG. 1, is adapted to slip over the valve body 16 to protect the same from the cooling system liquid flowing through the engine cooling passages through which the injector valve extends. The shielding jacket is apertured at its closed end to permit the same to be slipped over the valve body, with a sealing gasket 28 ebeing provided at such closed end for sealing the same. A sealing washer 30 is disposed within an annular groove 32 formed therefor in the exterior of the valve body for sealing the shielding jacket adjacent the open end thereof.

=T he valve body 16 is internally bored and is adapted to receive a poppet generally indicated at 34 and a retainer assembly generally indicated at 36. Referring initially to the latter such assembly, the same comprises a retainer sleeve 3S tbreadedly received in the valve body through an intermediate threaded section 40 which engages a threaded section 42 formed on the interior of the valve body. The retainer sleeve 38 is further formed with stepped shoulders 44 and 46, the former of which is adapted to tightly contact an annular shoulder 48 formed in the valve body for limiting the forward movement of the retainer assembly in the valve body. A pair of sealing rings 50 and 52 are disposed around the retainer sleeve 38 immediately forward of the shoulders 44 and 46 to seal the mounting of the retainer sleeve within the valve body.

The retainer sleeve 38 is formed relatively adjacent the forward end thereof with a plurality of radially directed shoulders commonly designated at 54 the outer ends of which terminate closely adjacent an inwardly directed annular shoulder 56 formed on the interior of the valve body. The shoulders 54 are arcuately spaced around the retainer sleeve and function not only to axially align the retainer sleeve within the valve body but permit flow of the fuel under pressure into the `annular chamber 58 formed between the valve housing bore and the periphery of the retainer sleeve. 'Ihe extreme forward end 60 of the retainer sleeve 38 is of substantially reduced diameter and is adapted to telescopically receive one end of a flexible, metallic sleeve generally indicated at 62, with the latter being preferably adhesively secured to and crimped on such forward end 60 of the retaining sleeve as indicated at 64. The flexible metallic sleeve 62 can be made from any commercially available metal having the required characteristics, and 300 series stainless steel has proved highly satisfactory for this purpose.

Fuel is directed to the interior of the valve by means of flexible, preferably metallic hypodermic tubing 66. The flexible tubing 66 enters the valve interior through a plastic, flexible protective tube or sheath 68 secured within the retainer sleeve at the adjacent end thereof by means of epoxy adhesive or the like. The protective tube 68 extends to the fuel control valve to which the flexible tubing 66 is connected. The forward end of the tubing 66 extends through a longitudinal opening provided therefor in the forward end 60 of the retainer sleeve 38, with suitable adhesive means being provided to secure the tubing in place within such retainer forward end. The tubing 66 is relatively thin-walled and diametrically relatively small, having, by way of example, an outside diameter of .0365 inch andan inside diameter of .0235 inch. The tubing is thereby relatively flexible to facilitate bending thereof if necessary, and the inside diameter is such as to supply the desired fuel quantities to the valve.

In the form shown a portion of the flexible tubing 66 is coiled in the cavity or chamber 69 defined by the intermediate section of the retainer sleeve through which the tubing extends. The use of flexible tubing capable of such bending is a distinct advantage over inflexible fuel lines commonly in use. By coiling the tubing where necessary, the length of tubing for all the injectors of the fuel system can be made the same, with the varying distances of the respective injectors from the fuel control valve being accommodated in each instance by coiling of the tubing within the chamber 69 the required amount. Thus, the injector most distant from the control valve will require little or no coiling of the flexible supply tubing while the injector located nearest the control valve will necessitate considerable coiling of the supply tubing. By employing equal lengths of tubing for each of the several injectors in the fuel system, the timing for the system can be accurately set at the control valve, with the response times for each injector being the same by virtue of the equal tube lengths. It will be apparent that the encased tubing 66 could also be coiled exteriorly of the valve as well.

The end of the poppet 34 disposed adjacent the forward end of the retainer sleeve 38 is adapted to telescopically receive the flexible sleeve 62 for relative movement under conditions to be hereinafter described. The flexible sleeve and the telescoping fit thereof around the poppet provide a distinct advantage in terms of manufacturing costs. The inside diameter of the sleeve and the outside diameter of the poppet can be manufactured with rather wide tolerances, with the subsequent collapsing and expanding of the sleeve during operation automatically effecting the desired tightness of t. Further, it will be apparent that the sleeve 62 serves to support the trailing end of the poppet and thus align the poppet in the housing and guide the movement thereof. A spacer 70 is provided within the flexible sleeve 62 at the end of the poppet to regulate and limit the rearward movement of the poppet during injection.

The poppet 34 further includes a relatively enlarged intermediate portion 72 having a forward, flat surface 73 and a curved rear surface 74, the latter forming a seat for a spring retaining member 76. A helical compression spring 78 seats at one end against such retainer and at its other end against an annular shoulder 80 formed on the retainer sleeve 38 immediately forward of the radial shoulders 54. The force of the helical compression spring 78 biases the forward end of the poppet valve to a seating position to prevent injection of the fuel from the nozzle 24, and during the injection period the spring is compressed, as will be hereinafter described.

As best seen in FIGS. 2 and 3, the forward end 82 of .the poppet 34 loosely fits within the forwardmost end portion 22 of the valve housing whereby fuel can be delivered through the annular chamber 83 formed therebetween to the forward end of the poppet. The poppet at such forward end 82 is further formed with a plurality of longitudinally extending grooves 84 to facilitate the delivery of the fuel to the forward end of the poppet. The extreme forward end of the poppet is conical shaped as indicated at 86 and is adapted to engage an annular edge 88 formed on the nozzle 24. Such edge contact, as well as the annular space between the poppet end 82 and the housing end 22, permits manufacturing without particular regard to close manufacturing tolerances, while at the same time providing highly satisfactory valve operation.

The nozzle 24 is internally threaded as indicated at 90 for mounting the nozzle on the exteriorly threaded forward end 22 of the valve housing. A passage 94, the inner end of which is defined by the edge 88, is formed in the nozzle, with the forward or outer end of such passage communicating with injector openings commonly designated at 96, the number and size of which can be varied as desired to achieve optimum fuel delivery to the combustion chamber. The nozzle 24 is further formed with an annular flat face 98 which is adapted to engage the adjacent end of the valve body thereby to accurately position and limit the mounting of the nozzle 24 on the forward end of the valve housing. As noted above, the particular design of the engine may require, for optimum operation, a nozzle having a particular injector opening arrangement, and the quick assembly and disassembly of the nozzle without necessitating replacement of the entire valve is an obvious advantage over present valve designs wherein the injector openings are formed in the valve body or in members which effectively constitute the valve body.

The valve housing, in the regions surrounding the poppet 34 and the flexible sleeve 62, defines an accumulator chamber comprising a main section 100 and a forward, relatively smaller section 102 in both of which the pressurized fuel accumulates prior to injection, as will be presently explained.

The operation of the fuel injection valve just described is as follows. Assuming the poppet is seated following injection, fuel is delivered to the valve through the flexible supply tube 66 at operating pressures ranging up to 20,000 p.s.i. The fuel emanates from the end of the tube 66 into the area defined by the leading end of the retainer sleeve 38 and the adjacently disposed end of the spacer 70, with the flexible sleeve 62 defining the radially outer limits of such area. The fuel entering the described area, being at control line pressure substantially higher than the pressure in the accumulator following injection, will act outwardly against the relatively thin wall of the flexible sleeve 62 thereby expanding the same away from the periphery of the spacer 70 and poppet 34 sufficiently to permit the pressurized fuel to flow along the thus formed annular opening into the accumulator chamber. The entire accumulator chamber and adjoining

passages

58 and 83 will eventually become filled or charged with fuel at control line pressure. The poppet remains seated against the annular edge or shoulder S8 during charging due to the combined forces of the spring 78 and the control line pressure.

To inject fuel from the valve, the control valve (not shown) functions to cut o the fuel supply to the supply line 66 thereby producing a drop in control line pressure. The pressure in the accumulator chamber and adjoining passages acting against the conical surface 86 and the forward end 73 of the intermediate portion 72 of the poppet is then sufficient to force the poppet rearwardly unseating the same and permitting injection of the fuel outwardly of the valve through passage 94 and injector openings 96. When the control line pressure at the beginning of the injection period drops olf, the pressure in the accumulator chamber forces the flexible sleeve 62 around the 'poppet but yet permits relative movement therebetween to effect unseating of the poppet. However,

additional drops in control line pressure cause the sleeve to tightly contract around the poppet thereby -to form a seal therewith to prevent leakage of the fuel from the accumulator chamber back through the supply line 66. The rearward movement of the poppet 34 compresses the spring 78 against the shoulder 80 of the retainer sleeve. The degree of movement of the poppet and the compression of the spring 78 are controlled by the length of the spacer 70. To provide more reliable sealing of the flexible sleeve 62, the sealing is desirably limited to the interface between the sleeve and the poppet, and not to the adjacent faces of the spacer 70 and the forward end 60 of the retainer sleeve. To preclude sealing in the latter area during injection, a slot 70u is formed in such adjacent face of the spacer.

As the fuel is injected into the combustion chamber through the injection openings 96, a progressive pressure drop occurs within the accumulator chamber due to the expansion of the fuel remaining therein. The force on the poppet due to the pressure within the accumulator chamber during the injection eventually becomes less than the compressive force of the spring 78, at which time the spring moves the poppet back to a position wherein the conical forward end 86 thereof seats on the annular shoulder 88 of the nozzle thereby terminating injection. The accumulator chamber is subsequently recharged as described to complete the cycle. It will be apparent that the quantity of fuel injected is dependent upon the injection pressure, i.e., the pressure in the accumulator at the beginning of the injection period, and the force of the spring 78 which controls the pressure in the accumulator at the termination of the injection period. The reseating of the poppet to terminate the injection period can also be controlled by reapplication of the control line pressure as regulated by the control valve.

It will be noted that the described valve construction is novel in many respects when compared to present injection valves of this general type. The fuel is delivered to the valve interior through a flexible fuel supply line and is supplied to the accumulator chamber through an annular opening provided by a resiliently distensible sleeve which is adapted to expand when subjected to the relatively high control line pressures. The employment of a flexible fuel supply line permits the same to be coiled within the retainer sleeve or exteriorly of the valve in the described manner thereby to allow use of supply lines of equal length. The valve is of simple construction and eliminates complemental mating surfaces requiring close manufacturing tolerances thereby providing substantial cost reduction.

There is illustrated in FIG. 4 a slightly modified valve construction. In this valve form the poppet generally indicated at 110 is formed with a further relatively enlarged portion 112 presenting a conical surface 114 adapted to engage the leading end of the flexible sleeve 116. The remainder of the valveV construction is generally similar, with the poppet 110 further comprising an intermediate, diametrically enlarged portion 118 adapted to contact and retain a spring retaining member 120. A helical compression spring 122 is disposed between the retainer 120 and an annular shoulder 124 formed on the retainer sleeve 126 relatively adjacent the forward end thereof. The reduced forward end 128 of the retainer sleeve 126 is adapted to receive the flexible sleeve 116 which is crimped thereto as indicated at 130. In the FIG. 4 form the valve nozzle has been integrally formed with the valve body, providing a flat annular shoulder 132 against which the forward conical end 134 of the poppet is adapted to seat. The pressurized fuel is adapted to enter the forward portion of the valve body adjacent the nozzle end thereof through a plurality of grooves commonly designated at 136 formed in the leading end 138 of the poppet.

The operation of the PIG. 4 form of injection valve is generally similar to that described above. In this form,

however, when the poppet is unseated during injection, the conical section 114 of the poppet contacts the leading curved edge of the flexible sleeve 116 thereby providing a tight seal and preventing fuel leakage back through the area between the end of the poppet and the flexible sleeve 116 to the supply tubing 140. At substantially the same time as the conical section 114 of thepoppet engages the curved leading end of the flexible sleeve, the bottom of the poppet will engage the leading end of the retainer, and thus the force moving the poppet rearwardly will not be absorbed completely by the leading edge of the retaining sleeve.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A fuel injection nozzle valve comprising a valve body having an outlet portion defining injector opening means, a poppet within said body having a forward end portion adapted to close said opening means, spring means biasing said poppet to a closed position, said poppet and said body defining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, means for supplying fuel under pressure to said valve, and flexible sleeve means telescopically disposed around the trailing end of said poppet, said sleeve being expanded by said pressurized fuel during valve pressurization to provide an annular passage between said sleeve and said poppet to permit delivery of said fuel to said accumulator chamber prior to injection, said sleeve being collapsed tightly around said trailing end of said poppet by the pressure in the accumulator chamber during injection thereby to prevent leakage of fuel from said accumulator chamber to said supply means.

2. The combination of claim 1 wherein said flexible sleeve means is of metallic material.

3. The combination of claim 1 wherein said means for supplying fuel under pressure to said valve comprises a metallic tube the leading end of which terminates within said flexible sleeve adjacent the trailing end of said poppet.

4. A fuel injection nozzle valve comprising a valve body having an outlet portion defining injector opening means, a retainer sleeve within said body and secured thereto, a poppet within said body forwardly of said retainer sleeve having a forward end portion adapted to close said opening means, spring means biasing said poppet to a closed position, said poppet and said body defining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, means for supplying fuel under pressure to said valve, and flexible sleeve means telescopically disposed closely around the trailing end of said poppet and secured to said retainer sleeve, said sleeve being expanded by said pressurized fuel during valve pressurization to provide an annular passage between said sleeve and said poppet to permit delivery of said fuel to said accumulator chamber prior to injection, said sleeve being collapsed tightly around said trailing end of said poppet by the pressure in the accumulator chamber during injection thereby to prevent leakage of fuel from said accumulator chamber to said supply means.

5. The combination of claim 4 wherein said flexible sleeve means is metallic and wherein said means for supplying fuel to said valve comprises a flexible metallic tube extending through said retainer sleeve and terminating within said flexible sleeve adjacent the trailing end of said poppet.

6. A fuel injection nozzle valve comprising a valve body having an outlet portion defining injector opening means, an axially movable poppet within said body having a forward end portion adapted to close said opening means, an elongated, axially fixed retainer sleeve within said body and secured thereto and having a reduced forward end portion of relatively the same diameter as said poppet and disposed adjacent to the trailing end thereof, spring means interposed between said retainer sleeve and said poppet for biasing said poppet to a closed position, said poppet and said body delining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, means for supplying fuel under pressure to said valve, and flexible metallic sleeve means telescopically disposed within said spring and around the trailing end of said poppet and the reduced forward end of said retainer sleeve and secured to `the latter, said sleeve thus serving as a means of support for said poppet, said sleeve being expanded by said pressurized fuel during valve pressurization to provide an annular passage between said sleeve and said poppet to permit delivery of said fuel to said accumulator chamber prior to injection, said sleeve being collapsed relatively tightly around said trailing end of said poppet by the pressure in the accumulator chamber during injection thereby to prevent leakage of fuel from said accumulator chamber to said supply means.

7. The combination of claim 6 wherein said means for supplying fuel to said valve comprises a flexible metallic tube having an outer end exteriorly of the valve for communication with a controlled source of fuel and an inner end extending through and secured to the forward end of said retainer sleeve.

8. A fuel injection nozzle valve comprising a valve body having a reduced forward end portion, a nozzle removably secured to such forward end portion, said nozzle being formed with injector openings and a passage cornmunicating such openings with the interior of said valve, a poppet within said body having a forward end portion disposed within and spaced from said reduced forward end of said valve body, said poppet being adapted to close said passage, spring means biasing said poppet to a closed position, an accumulator chamber defined by said body in which pressurized fuel collects during valve pressurization, means for supplying fuel under pressure to said valve, and exible sleeve means telescopically disposed around the trailing end of said poppet, said sleeve being expanded by said pressurized fuel during valve pressurization to provide an annular passage between said sleeve and said poppet to permit delivery of said fuel to said accumulator chamber prior to injection, said sleeve being collapsed tightly around said trailing end of said poppet by the pressure in the accumulator chamber during injection thereby to prevent leakage of fuel from said -accumulator chamber to said supply means.

9. A fuel injection nozzle valve comprising a valve body having an outlet portion defining injector opening means, a poppet within said body having a forward end portion adapted to close said opening means, spring means biasing said poppet to a closed position, said poppet and said body defining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, said poppethaving an intermediate, enlarged portion presenting a rearwardly directed conical surface, means for supplying fuel under pressure to said valve, and flexible sleeve means telescopically disposed around the trailing end of said poppet, said sleeve being expanded by said pressurized fuel during valve pressurization to provide an annular passage between said sleeve and said poppet to permit delivery of said fuel to said accumulator chamber prior to injection, said sleeve being formed with a curved leading edge adjacent said conical surface of said enlarged portion of said poppet, said conical surface tightly contacting said curved edge substantially simultaneously with injection responsive to a drop in pressure in said .fuel supply means, thereby preventing leakage of fuel from said accumulator chamber to said fuel supply means.

10. A fuel injection nozzle valve comprising a valve body having an outlet portion defining injector opening means, a retainer sleeve within said body and secured thereto, a poppet within said body forwardly of said retainer sleeve having a forward end portion adapted to close said opening means, spring means biasing said poppet to a closed position, said poppet and said body defining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, flexible tube means for supplying fuel under pressure to said valve, said retainer sleeve being constructed and arranged to provide a chamber through which said flexible supply tube extends, said chamber being of a transverse dimension substantially in excess of the diameter of said supply tube thereby to accommodate coiling thereof, and means intercommunicating said exible supply tube and said accumulator for supplying fuel thereto.

11. A fuel injection nozzle Valve comprising a valve body having an outlet portion defining injector opening means, a poppet within said body having a forward end portion adapted to close said opening means, spring means biasing said poppet to a closed position, said poppet and said body defining therebetween an accumulator chamber in which pressurized fuel collects during valve pressurization, means for supplying fuel under pressure to said valve, axially fixed sleeve means telescopically disposed around and supporting the trailing end of said poppet, said sleeve means thereby serving to align said poppet in said housing, said sleeve and said poppet being spaced when fuel under pressure is supplied to said sleeve to dene an annular passage for supplying such fuel to said accumulator chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,746,856 2/1930 French 239534 1,967,987 7/1934 Broege 239-96 2,534,874 12/1950 Mettler 239-534 EVERETT W. KIRBY, Primary Examiner.

Claims

11. A FUEL INJECTION NOZZLE VALVE COMPRISING A VALVE BODY HAVING AN OUTLET PORTION DEFINING INJECTOR OPENING MEANS, A POPPET WITHIN SAID BODY HAVING A FORWARD END PORTION ADAPTED TO CLOSE SAID OPENING MEANS, SPRING MEANS BIASING SAID POPPET TO A CLOSED POSITION, SAID POPPET AND SAID BODY DEFINING THEREBETWEEN AN ACCUMULATOR CHAMBER IN WHICH PRESSURIZED FUEL COLLECTS DURING VALVE PRESSURIZATION, MEANS FOR SUPPLYING FUEL UNDER PRESSURE TO SAID VALVE, AXIALLY FIXED SLEEVE MEANS TELESCOPICALLY DISPOSED AROUND AND SUPPORTING THE TRAILING END OF SAID POPPET, SAID SLEEVE MEANS THEREBY SERVING TO ALIGN SAID POPPET IN SAID HOUSING, SAID SLEEVE AND SAID POPPET BEING SPACED WHEN FUEL UNDER PRESSURE IS SUPPLIED TO SAID SLEEVE TO DEFINE AN ANNULAR PASSAGE FOR SUPPLYING SUCH FUEL TO SAID ACCUMULATOR CHAMBER.