US1132284A - Variable-stroke fuel-pump. - Google Patents

Description

0. P. PERSSON.

VARIABLE STROKE FUEL PUMP.

APPLICATION FILED DEC. 30, 1912.

Patented Mar. 16, 1915.

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OTTO F. PERSSON, 0F ERIE, PENNSYLVANIA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

VARIABLE-STROKE FUEL-PUMP.

Specification of Letters Patent.

Patented Mar. 16, 1915.

Application filed December 30, 1912. Serial No. 739,217.

To all whom it may concern:

Be it known that I, om F. PERSSON, a citizen of the United States, residing at Erie, county of Erie, State of Pennsylvania, have invented certain new and useful Improvements in Variable-Stroke Fuel-Pumps, of which the following is a specification The present invention relates to variable stroke fuel pumps for internal combustion engines, and more especially for such engines when working on the high compression constant pressure plan where the fuel has to be injected into the pulverizers or injectors against the relatively high blast pressure utilized to inject fuel such as crude oil' into the cylinder when the fuel valve is opened.

In such engines the quantity of fuel delivered at each working stroke of the pump has to be closely regulated to maintain constant speed of the engine shaft under varying loads. For low engine speeds this problem is relatively much simpler than for high engine speeds because, in the latter case, the pumps fail to work properly due to the fact that the time interval between strokes is so short that the cylinders cannot fill.

I overcome the difficulty above referred to by providing a pump for each engine cylinder or group of cylinders having two plungers. each operating at half the speed which would be required for the ordinary pump under like conditions. The plungers operate in alternation, each having its own suction and discharge valves, a discharge pipe common to both pumps being provided. The

plungers'are attached to a walking beam actuated by any suitable means such as an eccentric on a reduced speed shaft. In the driving connection is a sliding block to change the stroke of the plungers whose position is determined by a speed governor. "he pump is also provided with a by-pass valve on the discharge side which is connected to and actuated by the starting lever of the engine so to prevent fuel from entering the pulverizer or pulverizers and causing dangerous pressures in thecylinder on the first firing stroke after the starting operation. 1* or simplicity I have shown only one engine cylinder with its pump but it is to be understood that the arrangement can be duplicated at will, one governing means sutlicing for all.

In the accompanying drawing which is illustrative of my invention, Figure 1 shows an internal combustion engine equipped with my improved pump; Fig. 2 is a vertical section of the pump; and Fig. 3 is a detailed view showing the means for moving the starting valve lever into operation and the fuel valve lever out of operation.

1 indicates an internal combustion engine of any suitable character; as shown it is provided with two pistons 5 and 6, illustrated in dotted lines, and located in the same cylinder. The engine may have as many cylinders as'is desired.

7 indicates a cam shaft which is driven by the main shaft of the engine through suitable power transmitting means. The shaft 7 in addition to driving the cams also drives the vertical shaft 8 of the speed governor 9. The weights of the governor are connected to and move the sliding collar 10 up and down as the speed of the engine changes. Motion from the collar is transmitted to the controlling member... of the fuel pump by the bell-crank lever 11. Situated on one side of the cylinder is a fuel injector or pulverizer 12 of any suitable construction which is provided with a needle valve 13 for controlling the admission of fuel to the combustion space between the pistons 5 and 6. Located directly opposite the pulverizer isan air starting valve 14, shown in dotted lines. This is opened by the lever 15 and closed by the spring 16. The lever 15 is actuated by a link 17 that is connected to. a lever 18, the latter being mounted on an eccentric carried by the rock shaft 19.

Rigidly secured to the rock shaft is a hand lever 20, by means of which the fuel valve can be cut out of operation and the air starting valve into operation. The lever has three positions, an upright position when the engine is running under normal conditions, a horizontal position when the fuel valv'e'is cut out and the air starting valve is in operation, and a mid-position where both the fuel and 'air startingvalves arefcut out of operation. As will appear hereinafter, when the lever is ,in the starting and mid-positions a bypass valve in the fuel pump is open. to bypass fuel from the pulverizer.v The fuel pump comprises a pair of cylinders 25 and 26.. Thesecan with advantage be formed in the same casting. Each cylinder discharge valve '28. The suction valves receive fuel from a chamber 29. The admission of fuel to this chamber is under the con-- trol of a float 30 and valve 31. Fuel is supplied to the pump from any suitable source by the pipe 32.. Situated midway between the cylinders and rising. vertically is a boss 33 containing a conduit 34, to which both elements of the pump deliver fuel in alternation. The discharge valves 28 are so arranged that when one elementof the pump is active no fuel is permitted to pass from it to the .other element.

and 36 indicate the pump plungers which are connected by links 37 to the actuator 38, the latter being made in the .form

, of a walking beam and supported by a pivot 39 carried by the post, or support 40. The actuator is provided with a rectangular slot 41, in which is-located a sliding block 42. This block is connected to,the eccentric rod 43. Reciprocating motion is imparted to this rod by the eccentric 44, thatis mounted tending arm of the bell-crank lever 11 is connected by a link 46 to the eccentric rod 43. In this manner the position of the sliding block 42, which transmits power from the reduced speed shaft 44 to the pump actuator 38, is adjusted. As the block 42 is moved to the right the length of. each plunger stroke is decreased, and when moved to the left is increased.

During the period that the engine is being started and also whenit is desired to quickly stop the engine, it is important to prevent fuel from passing from the pump to the pulverizer. To accomplish this, a by-pass valve 47 is providedas shown in Fig. 2. The valve is provided witha central port 48, and is so arranged that when in the position shown both elements of the pump deliver all their fuel to the conduit 34. On the other hand, when the valve is rotated through approximately 90, the fuel instead of passing through the conduit 34 to the engine, is discharged through the port49 into the supply chamber 29. In order to insure the proper --actuation-of the by-pass valve an'arm 50 is mounted on itsspindle and said arm is connected by the rod 51 to an arm 52 carried by the rock shaft 19, which is moved by the handle 20. The partsare so arranged that when the handle 20 is in the mid' and horizontal positions. the by-pass valve 47. is fi sz aand-whenin the upright position is c Referring to Fig. 3, 19 indicates the rock shaft and mounted thereon are two eccentrics 53 and 54, the latter being shown in dotted lines. Mounted on the eccentric 53 is a lever 55 for actuating the fuel valve, and mounted on the eccentric54 is the lever 18- for actuating the air starting valve. These levers are actuated by cams carried on the shaft 7. By moving the-handle 20 the positions of the levers 55 and 18 are changed, one leverbeing moved into operation with its cam while the otherlever is moved out of operation.

By reason of my improved constructionv the pump can be operated at one-half the speed of the main shaft for a two-cycle en- 'ne and at one-fourth of the engine speed or a four-cycle engine. By thus decreasing the speed of the pump. ample opportunity is provided for the fuel to flow into the c linders on'the suction strokes and there ore the engine can be operated at very high speed with the certainty that the pumps will operate properly. Reducing the speed of the pump also reduces the wear thereon and renders it less liable to get out of order. This is of especialiimportance where a num: ber of pumps are driven as a unit, each supplying its own cylinder, since the partial failure of one pump, as by reason of excess leakage, will produce irregularities in the operation of the engine.*

In accordance with the provisions ofv the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative,an'd that the invention canbe carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is.-

1. The combination of an internal combus-J tion engine, a starting means, a fuel injector,

a pump having alternately acting plungers,

an actuator common to both, a conduit receiving highpressure fuel from allof the 'pump plungers and'conveying it 'to' the injector, a by-pass valve in the conduit, means for varying the stroke 'of the pump, and a lever for moving the starting means to operative position and simultaneously therewith moving the by-pass valve to a position where it by-passes fuel from the injector.

2. The combination with an internal combustion engine having an air starting means,

and a fuel injector, of a fuel pump comprising a pair of cylinders, alternately acting plungers mounted therein, a fuel supply chamber, a pivotally supported actuator for the plungers, a shaft'operated by the 'engine for driving the actuator, a common discharge ipe for the cylindersconnected to the fue injector, a by-pass connecting the discharge conduit to said fuel supply chamber, a valve therein, and a single lever for moving the air starting means to operative position and opening the valve in said bypass.

3. The combination With an internal combustion engine having fuel admission means, of a pump for supplying fuel thereto comprising a casing containing a fuel chamber, a single casting therein carrying a pair of cylinders, plunger-s in the cylinders, separate suction and discharge valves for each cylinder, a common delivery pipe therefor connected to the fuel admission means, a Walking beam having an elongated slot located on one side of its pivot, links connecting said beam to the plungers, a member adapted to slide in said slot, a speed reduction shaft, an eccentric thereon, means connecting the member to the eccentric for operating the pump plungers, and means for sliding said member in said slot to vary the efi ective stroke of the pump.

In witness whereof, I have hereunto set my hand this 26 day of Dec, 1912.

OTTO F, PERSSON.

Witnesses:

HERMANN LEMP, L. V. STOELTZLEN.

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