US1989891A

US1989891A - Fuel injection device

Info

Publication number: US1989891A
Application number: US128077A
Authority: US
Inventors: Carl G Sprado
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1926-08-09
Filing date: 1926-08-09
Publication date: 1935-02-05
Anticipated expiration: 1952-02-05

Description

Feb. 5, 1935.

c. G. SPRADO FUEL INJECTION DEVICE Filed Aug. 9, 1926 2 Sheets-Sheet l Feb. 5, 1935- c. G. SPRADO 1,989,891

FUEL INJECTION DEVICE Filed Aug. 9, 1926 2 Sheets-Sheet 2 Patented Feb. 5, 1935 UNITED STATES PATENT OFFICE.

FUEL INJECTION DEVICE Application August 9, 1926, Serial No. 128,077

1 Claim.

This invention relates in general to improvements in the construction and operation of fuel injection devices, and is especially applicable to internal combustion or oil engines of the direct 5. injection type.

An object of the invention is to provide an improved fuel injection device which is simple in construction and efficient in operation. Another object of the invention is to provide a new and 10 usefulfuel supply pump for internal combustion or oil engines of the direct injection type. A further object .of the invention is to provide a fuel injection pump for multi-cylinder oil engines or the like, wherein uniform supply of fluid is 1.3 insured for all of the individual cylinders. These and other objects of the invention will appear from the following description.

A clear conception of several embodiments of the invention and of the mode of operating fuel 20 injection devices constructed in accordance therewith, may be had by referring to the drawings accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the vari- 25 ous views.

Fig. 1 is a central vertical section through one form'of the improved fuel injection device and through the actuating mechanism therefor.

Fig. 2 is a longitudinal sectional view through another form of the improved fuel injection device especially applicable to multi-cylinder engines.

Fig. 3 is a transverse sectional view through the fuel injection device of Fig. 2, showing a 3 regulator diagrammatically associated therewith. Fig. 4 is a top view of the fuel injection device disclosed in Figs. 2 and 3. I

Referring specifically to the embodiment of the invention illustrated in Fig. 1, the fuel injec- 0 tion device comprises in general a stationary casing forming a displacement chamber 2; a movable member or plunger 4 having an end face constantly exposed to the displacement chamber 2; a reciprocable piston 3 for introducing liquid 5 such asfuel oil, into the chamber 2; an inlet valve 6 operable by the movement of the piston 3 to permit the flow of liquid into the chamber 2; a discharge valve 5 for controlling the delivery of liquid from the chamber 2; mechanism for J actuating the piston 3; and means for varying the pressure tending to urge the plunger 4 toward the chamber 2. The instrumentalities for varying the pressure tending to urge the plunger 4 toward the chamber 2, consist of a pressure 5 chamber 12 having an adjusting piston 13 exposed thereto, and adapted to receive a supply of compressible fluid under pressure past-the adjustable regulating-valve 14. The plunger 4 is constantly urged away. from the displacement chamber 2 by means of a compression spring 11, 5 this spring opposing the pressure acting upon the piston 13 within the chamber 12. The liquid supply piston 3 is reciprocable with respect to the displacement chamber 2 by means of an actuating arm 15 having a roller 18 thereon 00- acting with an actuating cam 'or eccentric 16 associated with a constantly rotating shaft 1'7. The piston 3 is urged away from the displacement chamber 2 by means of a compression spring 10, this spring at all times maintaining the roller 18 in engagement with the peripheral surface of the eccentric 16. The-inlet valve 6 is normally spring pressed against its seating to cut off the flow of fluid from a supply pipe 8 to the displacement chamber 2. An unloading 20 rod 9 cooperates with the inlet valve 6 to maintain this valve open during a predetermined portion' of the pressure stroke of the piston 3, under certain conditions of operation. The unloading rod 9 is connected to one end of a lever 19, the opposite end of which is connected to the arm 15 by a connection 22, and the medial portion of which is fulcrumed upon an eccentric 20. The eccentric 20 is adjustable in position by means of regulating mechanism such as a governor, associated with the connection 21. The discharge valve 5 is formed to control the delivery of liquid from the displacement chamber 2 to the dis charge line 7, the valve 5 being normally spring pressed against-its seating. The discharge line 7 may have a second fuel injection valve of usual form therein, for controlling the delivery of liquid to a source of utilization such as a cylinder of an oil engine.

Referring specifically to the embodiment of the 0 invention illustrated in Figs. 2, 3 and 4, which embodiment is especially applicable to multi-cylinder engines or the like, the fuel injection device comprises, a fuel supply chamber 23 communicating with a common displacement chamber 27formed within a suitable stationary casing, the

chambers

23, 27 being connected by passages or conduits 41 each having a discharge valve 40 therein; a common member or plunger 26 constantly movable toward and away from the displacement chamher 27 to establish a predetermined pressure therein; and a series of reciprocable pistons 28 for introducing definite quantities of liquid into .the displacement chamber 27 from the supply chamber 23 through the passages 41. The chamher 23 has a supply line 24 communicating therewith, and is also provided with a vent passage 44 for permitting the escape of air. The displacement chamber 27 communicates with a discharge line 25 which normally conducts the fuel oil to the injection devices or valves at the engine, these valves being of well known construction and being formed to permit delivery of oil from the discharge line 25 to each cylinder at predetermined intervals. The plunger 26 is constantly urged toward the chamber 2'7 by means of a compression spring 38 the tension of which is variable by means of an adjusting screw 39. Each of the pistons 28 is provided with a compression spring 37 for urging the piston away from the adjacent conduit 41, against an actuating eccentric 30. The actuating eccentrics are carried by a common shaft which is supported at the medial portions of a pair of adjusting arms 31, the corresponding ends of which are secured to a common pivot shaft 42, and the opposite corresponding ends of which are associated with a cross-rod 32. The eccentrics 30 are constantly rotatable by means of gearing 33 and an actuating shaft 34 which is driven by the engine. The cross-rod 32 is connected to a governor 36 or other means-for varying the position of the arms 31 with respect to the pivot 42, by means of connections 35. Each of the discharge valves 40 is spring pressed toward its seating and is accessible by virtue of a removable cap 43 associated with the main casing of the injection device.

During normal operation. of the injection device illustrated in Fig. 1, the shaft 17 is being rotated thereby causing the eccentric 16 to reciprocate the piston 3 through the roller18 and the arm 15. As the piston 3 is withdrawn from the displacement chamber 2, the discharge valve 5 remains closed and the inlet valve 6 is opened by the suction due to the withdrawal movement of the piston to admit a full quantity of liquid to the chamber 2 from the supply line 8. 'If the unloading rod is withdrawn so as not to engage the valve 6, then this valve will engage its seating when the piston 3 has reached its lowermost position and will remain seated during the entire upward stroke of the piston 3. If the injection valve at the engine is open, when the piston 3 moves upwardly, liquid is discharged from the displacement chamber 2 past the valve 5 by the action of the plunger 4. If the injection valve is closed when the piston 3 moves upwardly, then the oil in the chamber 2 merely causes the plunger 4 to move away from this chamber. The moment the injection valve of the engine is open, the plunger 4 immediately becomes effective to urge oil through the discharge line 7 to the engine at a predetermined constant pressure and independently of the motion of the piston 3. If the pressure in the chamber 12 is varied, the plunger 4 will assume a new position in accordance with such variation of the pressure in the chamber 12. When the rod 9 is adjusted to engage the inlet valve 6 during a portion of the upward stroke of the piston 3, some of the oil within the displacement chamber 2 is returned to the supply line 8, and such return of liquid is immediately stopped when the rod 9 is withdrawn from the valve 6,. By varying the timing of the eccentric 16 the timing of the reciprocation of the piston 3 is also varied, anu such variation in the time of movement of the eccentric 16, is a well known expedient in the art. v

During normal operation of the modified fuel injection device disclosed in Figs. 2, 3 and 4, the

eccentrics 30 are being constantly rotated to reciprocate the pistons 28.. Due to the angular position of the eccentrics 30, the pistons 28 act successively to urge oil from the supply chamber 23 through the displacement conduits 41 and past the valves 40 to the common displacement chamber27. The plunger 26' is constantly movable toward and away from the displacement chamber 27 due to variation in the quantity of oil being delivered to the chamber 2'7 by the pistons 28 and also due to the successive opening of the fuel injection valves. The spring 38 however acts to maintain a constant pressure within the displacement chamber 27 regardless of the quantity of oil being supplied .by the pistons or the quantity of oil discharged, and this constant pressure may be conveniently varied by adjusting the set,

screw 39. As the pistons 28 supply oil to the chamber 27, the plunger 26 recedes from this chamber, and as the injection valves at the en- --gine are opened to admit fuel to the cylinders,

the plunger 26 becomes effective to urge the oil through these injection valves. The governor 36 Y operates to automatically adjust the arms 31 to vary the effective strokes of the piston 28 in an obvious manner, and the discharge valves 40 merely serve as check valves for preventing re- .turn of oil from the chamber 27 to the chamber 23.

From the foregoing description it will be apparent that the constantly movable plunger .serves to deliver oil at a predetermined pressure insures an abundant supply of fuel at the desired pressure regardless of the number of cylinders embodied in the engine to which the device is applied. i

It should be understood that it is not desired to limit the invention to the exact details of construction and operation herein shownand de-. scribed, for various modifications within the scope of the claim may occur to persons vskilled in the art.

It is claimed and desired to secure by Letters Patent:

A fuel injection pump for an internal combustion engine, comprising a casing forming a displacement chamber and a plurality of cylinders, a plurality of pistons disposed to reciprocate within said cylinders to displace fuel from said cham- Y her, a shaft having a plurality of eccentrics adapted respectively to engage the ends of said pistons, a pair of arms pivotally mounted on said casing and positioned to rotatably support said eccentric shaft in position to actuate said pistons, means for drivingsaid eccentric shaft including a rigidly mounted driving worm meshing with agear wheel on said eccentric shaft, and means responsive to changes in the speed of the engine for pivoting said arms to move said eccentric shaft relative to said casing and longitudinally CARL G. SPRADO.