US2221179A - Fuel injection pump - Google Patents

Description

Nov. 12, 1940. w. E. BUTTLE 2,221,179

FUEL INJECTION PUMP Filed Oqt. 29, 1936 2 Sheets-Sheet l MWQW 6m WOW i 0 M WU Nov. 12, 1940. w BUTTLE n 2,221,179

FUEL INJECTION PUMP Filed 001;. 29, 1936 i 2 Sheets-Sheet 2 Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE Walter E Buttle, Chicago, Ill., assigno1'-, by mesneq assignments, to :The New .York iTrustlCompany Application October 29, 1936; sen-arm. maize 2 Claims (01; 103 -38).

This invention has to dowith fuel injection pumps of the type used on Diesel engines.

The object of the invention is to provide a pump unit of improved desigmwhich will deliver extremely small yet accurately: metered quantities of solid fuel to the cylinders of-the engine, quickly-producing the requisite injection pressure at the nozfle in each cylinder and as quickly reducing the pressure at the end of the injection period, which is dependable" in operation, giving trouble free service over long periods of time under severe operating conditions, andwhich is aboveall characterized by its simplicity and accessibility, the design requiring but comparatively few parts, which parts can be made and fitted together with great accuracy, and the relative arrangement of the parts enabling the same to-be easily taken apart and reassembled for purposes of cleaning and repairing.

While the foregoing statement is indicative in a general way of the nature of the invention, other more specific objects and advantages will be apparent to those skilled in the art upon a full understanding of the construction, arrangement and operation of the parts combined to'form this improved pump unit. 1 I

A preferred embodiment of the invention is presented herein for the purpose of exemplifica tion, but it will of course be appreciated that the invention is susceptible of embodiment in other. structurally modified forms coming equally within the scope of the appended claims.

In the accompanying drawings: I

Fig. 1 is a partially sectional side View of the pump unit, sectioned on the line ll of Fig. 2 j

Fig. 2 is a vertical transverse section throughthe unit, taken on the line 2-2 of Fig. 1j and Fig. 3 is a side View of the unit, with certain of the main parts shown separated from eachother in order to illustrate the simplicity and accessibility of the plungers, barrels and valves;

Pumps of much the same general character have been manufactured and used before, but their cost of manufacture has been objectionably high because of the complicity of the design employed', and their use has been limited not only because of their cost but because of the difiiculties and inconveniences encountered in quickly getting at certain of the parts for the purpose of cleaning or repairing the same. The present invention resides in an improved design which is distinguished by thesimplicity and accessibility of its few parts. l

. The device shown in the drawings is a fourpump unit for application to a four-cylinder engine, but it will of course lee-understood that the device can be made up with any desired number; of individual pumps-in the unit. The casing of the unit is composed of three readily separable parts-namely, a housing IE! which forms the base, a body I I which, rests on top of the housing, and a fuel inlet manifold i2 which rests on top ofthebody. V I v v The body H is a solid horizontally elongated block of rather'flat rectangular cross section. It contains a rowof four upright cylindrical bores l3 in the top near the front ed ge and; a row of four inclinedcylindrical-bores M in the topnear the rear edge, which inclined bores I4 extend downwardly and forwardly through the bottom and are connected with the corresponding upright bores [3 by means of L-sha'ped fuel passages [5; The passages I5 lead from the front sides'of the bores I4'forwardlyjandupwardlyinto the bottoms of the bores !3. Just below thelevel of the passages IS the bores M are provided with annular shoulders l6 which divide the same into upper large diameter portions l1 and lower small diame ter portions l8.

Each of the upright bores l3 contains a downwardly spring-pressed discharge valve IQ which coactswith a seat '26 formed in"the"bot'tom of a cup-shapedcage 2!. The seat 20 in the cage clamps the cage tightly in position. The nipple 22 is connected at its upper endto one of the 'fuellines 23 of the associatedengine by means of a coupling nut 24. v n

, Each of the inclined bores IA contains a plunger barrel 2 5,'a valve cage 26 and a sleeve'nut 21, in

- theorder named. The barrel 25 is positioned in the lower small diameter portion iii of the bore and projects downwardly and forwardly from the bottom of the body for some distance. it is held against downward movement by'an annular rib 28 at its upper end which occupies the-lower end of the enlarged portion l!- of the bore and'rest's upon the shoulder '16. I The barrel 25 is counter-I bored at its upper end for a shortdistance, and

the annular rib 28 on the outside of thebarrel is.

provided with a groove 2Q which registers with the endiof the passage-lain the side of the bore l4 and isvconnected with-the counterbored portion of the barrel by means of several small'radialand projects a short distance from the lower end of the same.

The valve cage 26 in each of the bores I4 is positioned on top of the barrel 25 in that bore and contains an upwardly spring-pressed inlet valve 32. The valve 32 acts against a seat 33 which is formed on the lower edge of a hollow boss 34 on the bottom of the cage 26. The boss 34 projects down into the counterbored upper end of the bar-. rel 25. The stem 35 of the valve 32 is mounted in another boss 35 of smaller diameter on the top of the cage. The space surrounding the upper boss 36 is connected to the chamber in the lower boss 34 by means of several small ducts 31.

The sleeve nut 21 in each of the bores I4 is screwed into the upper end of the bore, into tight- 1y clamped engagement with a small packing ring 38 on the top of the cage 26 in that bore, with the inner wall of the nut in radially spaced relation to the boss 36 on the top of the cage. The nut 21 holds both the barrel 25 and the cage 26 in place, and projects just far enough from the top of the body H to be engaged conveniently by a wrench.

The plunger 3| in the barrel in eachof the bores I4 is provided at its lower end with a collar 39, and a coil spring 43 is compressed between the collar 39 and a seat 4| which is formed in the bottom of the body about the lower end of the bore. The barrel 25 is encircled by the spring and serves as a guide for the same. The collar is held against axial movement on the plunger by engagement with a small shoulder 42 on the latter, and is provided with a radial slot 43 which permits its ready removal.

The fuel inlet manifold I2 is U-shaped in cross section and is cupped over all of the inlet valve retaining sleeve nuts 2! on the top of the body behind the discharge valve retaining nipples 32. The manifold I2 is clamped to the top of the body in fluid tight association with the latter by means of a plurality of cap screws 44 and is provided at one end with an opening 45 which is adapted to be connected with the main fuel line.

The body II is clamped to the top of the housing ll! by means of two studs 43 which project upwardly from the ends of the housing through holes in the ends of the body and are engaged at their upper ends by nuts 41. The housing H] is hollow and is divided by a horizontal partition 48 into an upper section 4!! and a lower section 50. The upper section 49 is occupied by those parts of the pump mechanisms which project downwardly from the body; the lower section contains a horizontally disposed cam shaft 5| and forms a chamber for the oil used in lubricating the cam shaft; and the partition 43 provides a support for a row of cam actuated tappet mechanisms 52 and also a support for a horizontally disposed control shaft 53. The cam shaft 5| is adapted to be connected in any suitable manner with the crank shaft of the associated engine, and is located with its axis intersecting the inclined axes of the plungers 3|. The tappet mechanisms 52 are located in axial alignment with the plungers 3| above earns 54 formed on the cam shaft 5|.

Each of the tappet mechanisms 52 consists of a solid cylindrical body 55, a sleeve 55 about the body, a hollow tappet rod 51 screwed into the upper end of the body, an oil shield'58 cupped over the body and sleeve, a jam nut 59 screwed on the rod 51 above the shield, and a cam following roller 60 journaled in the lower end of the body in vertically spaced relation to the lower end f the rod 51. Each of these tappet mechanisms slides up and down in a guideway 6| which is formed in the partition 48 beneath each of the pump assemblies. The control shaft 53 extends through vertically elongated openings in the sides of all of the tappet mechanisms, in the spaces present between the rods 51 and the roller 6!). The shaft 53 is provided at the locations of each tappet rod 51 with a flattened cam face 62 which engages the rod during the downstroke of the latter and determines its lowermost position. The line contact resulting from the hollow character of the lower end of the rod 51 enables a fine adjustment to be obtained.

The control shaft 53 can be operated by hand or can be connected with a governor of any suitable character, such as one which is responsive to variations in the vacuum present in the inlet manifold of the associated engine, to permit the supply of fuel to the engine to be accurately regulated by the control shaft in accordance with the engine requirements. The control shaft is shown in its full load position in Fig. 2. In this position the four pumps in the unit will deliver their maximum charges of fuel to the injector nozzles in the cylinders of the engine. By turning the control shaft in either direction the working strokes of the plungers will be progressively shortened until a point is reached at about 90 where theplungers will not move at all and no fuel will be delivered.

The upper section 49 of the housing I0 is provided with a removable cover plate 63, for access to the tappet rods 51 in adjusting the same, and

is also provided with a removable screw plug 64 or other connection for draining out any fuel oil which may accumulate in time on the partition 48. The lower section 50 of the housing, which is adapted to. contain lubricating oil for the cam shaft 5|, is provided with an inlet for the oil into which a screw plug 65 equipped with a gauge blade 66 is screwed. V

It will be observed in Fig. 2 that the low parts of the cams 54 are quite short with respect to the high parts of the same, with the result that the control shaft 53 is relieved from the spring pressure of all the pumps with the exception of the one actually pumping at any particular instant, thereby reducing and equalizing the force required to operate the control shaft.

In operation, the plungers 3| are moved up and down in the barrels 25 by means of the cam shaft 5|, the interposed tappet rods 51 and the springs 40. The fuel oil which enters the inlet manifold |2 is drawn down past the inlet valves 32 by the plungers 3| during their spring-actuated downstrokes and is forced out past the discharge valves |9 into the fuel lines 23 by the plungers 3 I during their cam-actuated upstrokes.

The pump of this invention is a substantial improvement over earlier pumps in the simple arrangement of the bores l3 and I4 in the body the inclined positioning of the bores l4 which makes this arrangement possible, the shouldered support forthe plunger barrels 25 in the bores l4, and the stacked arrangement of the barrels 25, inlet valve cages 26 and sleeve nuts 2'! in the bores l4 beneath the fuel inlet manifold |2 in fixedly clamped but readily removable association.

With the construction described a positive control is had over the fuel fed to the engine, an equal quantity of fuel being injected into each cylinder, and such delivery being maintained uniform without the need of any adjustment other than the initial clearance adjustment between the tappets and the control shaft. This construction eliminates any need for the heretofore commonly used spill valve or by-pass valve openings, most of which have required a periodical readjustment due to the seemingly unavoidable uneven wear in the spill valve holes and other passages.

I claim:

1. In a pump of the character described, a body containing a cylindrical bore, which bore is provided intermediate its ends with an annular shoulder dividing the bore into, an upper large diameter portion and a lower small diameter portion, a plunger barrel in the small diameter portion of the bore projecting from the bottom of the body and having an annular rib in clamped engagement with the shoulder, a self-contained inlet valve unit in the large diameter portion of the bore in clamped engagement with the barrel, and a sleeve nut threaded into the large diameter portion of the bore in axially clamped engagement with but radially spaced relation to the valve unit, whereby to provide an annular fuel passage therebetween, said unit and barrel being withdrawable from the top of the body upon removal of the sleeve nut.

2. In a pump of the character described, a body containing a cylindrical bore, which bore is provided intermediate its ends with an annular shoulder dividing the bore into an upper large eter portion of the bore in clamped engagement with the valve unit, said unit including a cage which projects downwardly into the barrel and upwardly into the sleeve nut and is characterized intermediate its ends by a relatively thin annular clamping rib which overlies the top of the barrel and underlies the bottom of the sleeve nut, said unit also including a vertically reciprocating valve which seats against the bottom of the cage within the top of the barrel and is provided with a stem which extends upwardly through the cage to a point beyond the top of the latter, and a coil spring which surrounds the aforesaid upwardly projecting portion of the cage and is compressed between the top of the stem and the aforesaid clamping rib, in inwardly spaced relation to the inside of the sleeve nut, whereby to provide an annular fuel passage therebetween, and said unit and barrel being withdrawable from the top of the body upon removal of the sleeve nut.

WALTER E. BUTTLE.

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