US1934296A - Fuel injection unit - Google Patents

Description

NW, 7, 19330 H. a. A. BURNER FUEL INJECTION UNIT Filed May 22, 1929 Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE by mesne ents, to'Packard ompany, Michigan Motor Car Detroit, 'Mich, a corporation of Application my 22, 1929. Serial No. 365,094

ZGlaims.

. The invention relates to internal combustion engines of that type generally designated as Diesel and in which the fuel is injected at high pressure into a body of compressed air in the combustion chamber. It is the object of the invention to obtain a construction of fuel in- .iection unit which as such is attachable to the cylinder of the engine and which comprises the nozzle, a pump and a fuel supply connection. It is a further object to obtain a construction of unit so organized as to obtain uniformity in operation with accurate control of the quantity of fuel injected, even where this is exceedingly minute. Still further, it is an object to obtain a construction adapted for commercial manufacture and composed of comparatively few elements of simple construction. With these and other advantages in view, the invention consists in the construction as hereinafter set forth.

In the drawing:

Figure 1 is a section through a portion of the engine cylinder showing my improved fuel injection unit applied thereto and in longitudinal section;

of Figure 1;

Figures 3 and 4 are transverse sections respectively on lines 33 and 4 4 of Figure 1.

In the operation of internal combustion engines of the type above referred to and particularly in connection with cylinders having relatively small piston displacement and designed for high speed engines, it is of the utmost importance first to accurately control the quantity of fuel injected; second, to inject the fuel in a finely divided form orspray; third, to prevent clogging or stoppage in the fuel line, and fourth, to provide for a relatively large range of variation in the quantity of fuel used for correspondingly carrying the power and speed of the engine. My improved fuel injection unit is adapted to fulfill these conditions, first, by a nozzle construction adapted to finely :spray injected fuel while avoiding all danger of clogging; second, in rigidly connecting of discharge, the fuel injection and measuring pump; third, in supplying this pump with fuel which has been freed as far as possible from all clogging impurities as well as from air or gas bubbles. The specific construction of some of these elements has formed the subject matter of other patents taken out by me, including Nos. 1,690,893 of November 6, 1928 and 1,628,657 of May 17, 1928. The present invention, however, relates to the novel combination and organization Figure 2 is a sectional plan view on line 2-2 to this nozzlev and as close as possible to the point of these and other elements as hereinafter described.

Asspecifically shown, A is a rigid casing member adapted to be rigidly secured to the engine cylinder by suitable means such as the laterally 00 extending flanges B and the bolts C for clamping said member to a lug or bearing D on the cylinder. The casing A is boredon an axis perpendicular to the cylinder axis and is counterbored and threaded at its inner end to receive v the nozzle member E projecting through an aperture in the lug D to the interior of the cylinder. I The outer end of the casing A is also counterbored and threaded to receive a threaded plug or bushing F which in turn is bored and threaded to receive an adjustable threaded rod or stop member G. The plug F is fashioned at its inner end to form a, packing fiange surrounding a smooth inwardly projecting shank G of the member G.

The nozzle E is provided at its inner end with a flaring conical mouth portion E within which is arranged a knife edge yieldable sprayer valve H formed at the end of a shank H extending through the nozzle and intov the bore within the member A. The inner end of the shank H is threaded to receive a collar I forming an abutment for one end of a spring J which'is sleeved about said shank, the opposite ends of said spring abutting against a bearing on the nozzle E. A cap nut K engaging the threaded end of the shank H serves to lock the collar I and also forms a bearing for abutting against the stop member G, the arrangementbeing such that by adjustment of the collar I and cap nut K the spring J may be 90 properly tensioned and by adjustment of the stop member G the knife edge H may be arranged in very close proximity to the conical portion E of the nozzle but without actually contacting the same. The angle of the conical nozzle portion E is greater than the angle of the conical portion forming the knife edge H so that these two surfaces are non-parallel and the closest point of proximity is at the knife edge. Thus the liquid fuelwhich is ejected from the nozzle must pass 100 between the knife edge and the conical surface E' which parts are held together by the relatively heavy pressure of. the spring J If, however, the pressure of the liquid fuel is sufiicientand its speed of ejection too fastto pass through this restricted space, the spring J will yield, permitting a wider separation.

Projecting laterally from the casing member A is an integral threaded nipple A through which a tubular casing L may be rigidly attached ,9

to said member A. The member L contains the pump cylinder or barrel M which is inserted therein from the end engaging the nipple and which has a head M engaging a shoulder within the tubular casing. The pump barrel M at its head end is counter-bored to form a conical seat M for a ball check valve N controlling the outlet of the liquid fuel from the barrel. For greater certainty in action I preferably provide a double check valve and to this end there is inserted within the tubular casing L and between the head M and the nipple A a bushing 0 having a conical seat 0 for a second ball check valve N. Springs P and P are arranged to yieldably hold the check valves N and N normally to their respective seats, said springs abutting respectively on the shoulder 0 within the bushing O and a shoulder within the nipple A. A fluid passageway A extends through the nipple to the bore in the member A, thus establishing communication between the pump barrel and the nozzle.

As shown in Figures 1 and 3, the portion of the tubular casing L surrounding the upper portion of the barrel M is formed externally with conical seats Q, Q separated by an annular recess Q These seats are adapted to receive corresponding conical bearings on an annular member R which may be sleeved upon the member L and clamped to its seat by a nut S. Thus there is formed between members L and R an annular channel surrounding the barrel M and communicating therewith through registering ports L M The annular member R has an annular recess between the portions engaging the bearings Q Q within which is arranged an annular screen T. The screen T is of a diameter somewhat greater than that of the conical bearing Q so as to permit of being sleeved over said bearing with the member R. There are also gaskets T T at opposite ends of the screen which bear against the member R and form a sealing contact therewith leaving an annular space '1 therebetween. On one side of the member R is a transversely extending open ended channel R intersecting the annular space T so as to be in free communication therewith. At opposite ends of the channel R are hollow fittings U which are clamped to the member R by a central rod V threaded at its opposite end to engage clamping nuts V. Gaskets U are arranged to seal between the fitting U and the member R and also between said fittings and clamping nuts V. The fittings U are connected to conduits W which lead from the source of supply for the liquid fuel and also between diflerent cylinders of a multi-cylinder unit. Thus the fuel which is supplied bya low pressure pump (not shown) will pass through the channels R of each fuel injection unit of a multi-cylinder engine, while the fuel used by each unit will enter by way of the annular passage 1' through the screen T and annular recess in the member R and then through the ports L M into the pump barrel. This will avoid carrying clogging impurities which may be in suspension in the liqud fuel into each unit and in the same manner will avoid the forcing of air bubbles with the fuel into the high pressure pump barrel.

Within the pump barrel M is the pump plunger X which is attached at its outer end to a head X slidable within the casing L and actuated by suitable mechanism such as a tappet X. A spring Y sleeved around the barrel M and between the same and the casing L abuts at one end against a shoulder in the member L thereby forming a means for returning the plunger in the barrel.

With the construction as above described in operation the actuation of the tappet X will move the plunger X inwardly in the barrel M and as the end of said plunger passes the ports W will force the fiuid within the barrel past the check valves N and N and through the passage A into the casing A from which it will be expelled through the restricted space between the annular knife edge H and the flaring nozzle E. Assuming that all of the space between the barrel and the discharge end of the nozzle has once been completely filled with the liquid fuel, it is evident that the quantity of liquid discharged from the nozzle will correspond exactly to the displacement of the plunger after the ports M are closed. This is primarily due to the fact that the structure between the nozzle and the plunger is rigid and of such strength that the high hydraulic pressure on the liquid cannot produce any distortion. Also the presence of the double check valves N N' insures the cutting off of communication between the nozzle and the pump barrel prior to the retraction of the plunger. As before stated, the supply of fuel to the several cylinders is by way of the lateral channels R in each succeeding unit and this tends to carry away any air bubbles or other in suspension instead of forcing them into the pump barrel.

What I claim as my invention is:

1. A rigid fuel injection unit for an internal combustion engine comprising a rigid casing member carrying a nozzle, means for imposing a high resistance to the passage of fuel throughv said nozzle, a second rigid casing member can!- ing a ported pump barrel and a plunger reciprocable past the port, a bushing in the second casing, one-way valve means located in the end of the bushing nearest the first casing member and closing against said bushing, a second oneway valve located in the end of the pump barrel and closing thereagainst, said first mentioned 120 casing member being rigidly secured to but detachable from said second mentioned casin member and firmly clamping the bushing against the barrel, said bushing and first mentioned casing member together forming an inextensible passageway for the fuel from said barrel to said nozzle.

2. A rigid fuel injection unit foran internal combustion engine comprising a rigid casing member carrying a nozzle, means for imposing a m high resistance to the passage of fuel through said nozzle, 9. second rigid casing member carrying a ported .pump barrel and a plunger reciprocable past the port, a bushing in the second casing, one-way valve means located in the end of the bushing nearest the first casing member and closing against said bushing, a second one way valve located in the end of the pump barrel and closing thereagainst, said first mentioned casing member being rigidly secured to but detachable from said second mentioned casing member and firmly clamping the bushing against the barrel, said bushing and'first mentioned casing member together forming an inextensible passageway for the fuel from said barrel to said 145 nozzle, and said passageway having relatively short length and relatively small cross section.

impurities held 105

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