US2584408A - Injection pump for internalcombustion engines - Google Patents

Description

Feb. 5, 1952 J. E.-WlTZKY INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES INVENTOR JUL/US E. W/TZKY ATTORNEYS 0AM TRAVEL PLUNGER LIFT EVELOCITY Filed June 5, 1948 Patented Feb. 5, 1952 INJECTION PUMP FOR INTERNAL- COMBUSTION ENGINES Julius E. Witzky, Royal Oak, Mich., assignor to the United States of America as represented by the Secretary of the Navy Application June 5, 1948, Serial No. 31,232

Claims. (Cl. 299107.2)

This invention relates to new and useful improvements in fuel injector pumps for internal combustion engines. An object of the invention is to provide an in jector wherein only that part of the cam curve which has the highest velocity will be utilized for the injection of the fuel.

A further object of the invention is to provide a combined injection pump and injection nozzle.

Another object of the invention is to locate the combined I injection pump and nozzle in the cylinder head.

A further object of the invention resides in the provision of an injection pump actuated by the camshaft which operates the intakeand exhaust valves. An additional cam on said camshaft has therefore been provided.

Still another object of the invention is to provide an injector wherein the rocker arm which actuates the plunger operates on the, same shaft with the rocker arm which operates the valves.

Another object of the invention is to provide an injector wherein the beginning of the injection can be varied by changing the position of the eccentric.

I A further object of the invention is to cool the injector system by splashing fuel through the injection unit.

, The invention will be more readily understood from the following specification in connection with the accompanying drawings in which an example of the invention is shown. In these drawings,

Figure 1 is a vertical sectional view of the fuel pump unit and associated parts.

Figure 2 is a vertical sectional view of the fuel pump unit and associated parts taken on the line 2-2 of Figure 1 looking in the direction of the arrows. I

Figure 3 is a transverse horizontal section taken on line S3 of Figure 1 as viewed in the direction indicated by the arrows.

Figure 4 is a transverse horizontal section takenon line 4-4 of Figure 1 as viewed in the direction indicated by the arrows.

Figure 5 is a curve illustrating the relation of plunger lift and velocity.

In the drawings the numeral It designates the camshaft which actuates the plunger H of the injection pump. The same camshaft operates the intake and exhaust valves, not shown in the drawing. An additional cam I? therefore has to be provided. A rocker arm 13 actuating the plunger H is mounted on the common, rocker rm ha t This rocker arm shaft has an eccentric. l5 to control the amount of fuel injection- Only that part ofv the cam lift curve, which has the highest velocity, will be utilized for the injection of the fuel asis illustrated in Figure 5. A compensating piston i5 is provided for this purpose. the plunger H of the injection pump travels downward, the compensating piston travels upward until it reaches its stop ll. At this moment the actual injection will start and it will be terminated when the ring groove l8 of the plunger H reaches the port [9 of the barrel 2:). The ring groove :8 is connected by bores 2| and 22 with the space 23 beneath the plunger .H The rest of the fuel delivered by the upward stroke of the plunger will be spilled through the bores 2i and 22, the groove 3 and port 19, thus ending the actual injection.

Fuel is supplied through the suction valve 24 when the plunger H travels upward, .as isbest shown in Figure 2, which (valve) receives fuel from a suitable source of storage. Between barrel 2i] and the nozzle 25 an adapter plate '26 is provided. The adapter plate 26 has -a ring groove Z'l which connects the suction valve 24, the space 23 and the space beneath the compensating piston It. The barrel 20,- adapter plate 26 and nozzle 25 are fastened togetherby anassembly nut 28. V V 1 The rocker arm i3 actuating the plunger II is mounted on an eccentric l5 of the common rocker arm shaft 14 in order to control the injection amount of fuel. When this shaft 14 is turned, the position of the ring groove 18 is varied with respect to the port I9 in thevbarrel 20. Figure 1 shows the injection pump with plunger ll ina position approximately at the upper limit of its stroke. The dotted line indicates a position for full load. By this means, theamount injected of fuel may be variedand the speed ofthe engine controlled.

.By turning of the eccentric !5 from the posi-' tion 29 to the position 30; the roller 3| travels from position 32 to the position 33, the beginning of the injection may be varied togetherwith the variation of the amount of injection, depending on the original position of the eccentric IS.

The whole system is cooled by the flow of fuel therethrough under pressure. This flow is caused by the fuel supply pump, not shown in the drawings. If the cam l2 has a shape as shownin Figural, the ring groove l8 covers the port 49 when the plunger His at, the lower .limit of its stroke and. an amount of fuel flashes through the pump back tothetank. The runeer H is returned by a coiled spring 34, the compensating piston I6 is returned by a coiled spring 35. The metering valve 58 in the nozzle 25 is loaded by means of coil spring 36 and the suction valve 24 by a coil spring 31.

Any liquid fuel which may seep between the plunger and the surface of the bore'is collected in the groove 38, and goes back through the duct 39 together with the surplus fuel to the storage tank. The numeral 40 is the fuel inlet from storagetank, and 4| surplus fuel outlet to the storage tank. The unit injector is conveniently and securely fastened in place by means of a flange 42 and is readily removable when necessary.

The operation is as follows:

When the engine is operating, the injection pump will be actuated by the camshaft It). Upon rotation of camshaft H), the cam l2 lifts the roller 3| and the rocker arm I3 pushes the plunger ll of the injection pump downward. The compensating piston l6 travels upward until it reaches its stop l1. At this moment the plunger H has traveled to the point 44 of the lift curve, shown in Figure 5. That means the plunger H has a high velocity which is important for a fast injection. At this position in the stroke of plunger H the fuel oil under relatively high pressure is forced around through groove 21, down through channels 50, around groove 52, down through channel 54 to the underface of metering valve 58 which is thereby lifted from its seat against the biasing action of spring 36 and the fuel oil is injected at relative- 1y high velocity and pressure thence through nozzle 25 into the cylinder of the motor. The actual injection will be terminated when the ring groove l8 of the plunger ll reaches the port IS). The rest of the fuel taken in by the upward stroke of the plunger ll will be spilled through this port l9, thus ending the actual iniection.

Fuel is supplied through a suction valve 24 when the plunger II travels upward. The rocker arm l3 acutating the plunger H is mounted on an eccentric of the rocker arm shaft N. If the rocker arm shaft I4 is turned, the position of the ring groove I8 is varied with respect to the port I9, that means the amount of fuel per injector stroke will be varied and the speed of the engine controlled.

By turning the eccentric [5, the quantity of fuel injected and the beginning of the injection may be varied simultaneously, depending on the original position of the eccentric.

Various changes in the size and shape of the different parts, as well as modification and alteration may be made within the scope of the appended claims.

Having illustrated and described a preferred form of the invention, what I claim is:

1. A fuel injection pump structure for high velocity injection of fuel into an internal combustion engine having a camshaft and a rocker arm shaft, said pump structure mounted on the cylinder head of said engine, comprising a pump body, an injection nozzle depending from said pump body and projecting through said cylinder head, a spring biased valve for control of fuel flow through said nozzle, a fuel inlet conduit in said pump body, a spring biased check valve for the control of fuel flow through said inlet conduit, a fuel outlet conduit in said pump body, spaced chambers in said pump body, an adapter plate provided with an annular groove in its top surface, said plate positioned in said pump body below said inlet conduit and said spaced chambers so that said annular groove provides fuel flow communication therebetween, a spring biased plunger in one of said chambers, a rocker arm rotatably mounted on said rocker arm shaft, one end thereof bearing on the external end of said plunger, a cam mounted on said cam shaft bearing on the other end of said rocker arm, said cam contoured for a relatively rapid thrust, a relatively long period of dwell at the maximum thrust and a relatively rapid return to the low position, a spring biased compensating plunger in the other of said chambers, adjustable stop means in said other chamber to limit the movement of said compensating plunger and a duct in said pump body communicating with said fuel outlet conduit and through ducts in said plunger with the space therebeneath whereby when said plunger is at the position of maximum thrust the injection of fuel through said nozzle is terminated and fuel oil under pressure flows from said inlet conduit through the ducts in said plunger, through the said duct in said pump body to said fuel outlet conduit to thereby effect a cooling of said pump body. 1

2. The structure as defined in claim 1 which comprises an adapter plate having a body portion, an annular groove in the top surface of said body portion and a plurality of ducts extending normally from said groove through said body portion.

3. The structure as defined in claim 1 which comprises an injection nozzle havinga cylindrical body portion and an enlarged head portion in close contact with the under surface of said adapter plate, a valve seat and spring biased valve in said body portion, an axially positioned duct communicating with said valve seat and with a discharge orifice in the lower surface of said body portion, an annular groove in the top surface of said head portion in alignment with the ducts in said adapter plate and a duct in said head portion connecting said annular groove with the upstream side of said valve seat, whereby, as the pressure on said fuel oil is increased by said plunger, said fuel oil flows through said adapter, through the duct in said head portion to said valve seat, lifts said valve and discharges at high velocity through said orifice into space in said cylinder head.

4. The structure as defiined in claim 1 which comprises a spring biased plunger having a cylindical body extending into and adapted to be reciprocated in said one chamber, an annular groove positioned in the lateral surface of said plunger to be in alignment with said duct in said pump body when said plunger is at the limit of inward travel, a diametrically transverse duct in said plunger communicating at both ends with said annular groove and an axial duct in said plunger communicating -with said transverse duct and with the lower surface of said plunger.

5. The structure as defined in claim 1 which comprises a rocker arm having an arm rotatably mounted at about its midpoint on an eccentric securely attached to said rocker arm shaft, one end of said arm in contact with the external end of said plunger and the other end of said arm provided with a roller held in contact with the cam on said camshaft whereby rotation of said rocker arm shaft moves the roller in contact with said cam forward or backward with respect thereto thereby increasing or decreasing the 5 amount of fuel oil drawn into said one chamber Number by said plunger during the return stroke. 2,144,861 JULIUS E. WITZKY. 2,260,414 2,296,357 REFERENCES CITED 5 2,301,435 The following references are of record in the 2,313,264 file of this patent: 3 283 333 UNITED STATES PATENTS Number Name Date 10 1,867,383 Sass July 12, 1931 Number 1,993,369 Goldberg Mar. 5, 1935 25,331 2,071,237 Rupprecht Feb. 16, 1937 562, 6

Name Date Truxell, Jr Jan. 24, 1939 Thaheld Oct. 28, 1941 Links et a1 Sept. 22, 1942 1V Iercier Nov. 10, 1942 Reggio Mar. 9, 1943 Davidson Feb. 12, 1946 Bremser Sept. 24, 1946 FOREIGN PATENTS Country Date Netherlands 1931 Great Britain 1944

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