US2501074A - Fuel pump - Google Patents

Description

Mar 21 1950 D. E. MEITZLER 9 19 FUEL rum Filed Jam. 16, 1945 2 Sheets-Sheet 1 FiGE.

INVENTOR March 23, 1950 D. E. MJEITZLER 295019074 FUEL PUM] Filed Jan. 16, 1945 2 Sheets-Sheet 2 i NVENT Patented or. 21, 1950 rust rum "tr Donald E. Meitzler, Manchester, Conn, assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application January 16, 1945, Serial No. 573,108

8 Claims.

The invention relates to a fuel injection device particularly oi' the accumulator type in which fuel under pressure is collected in a chamber and is caused to discharge from the chamber by a drop in pressure in the inlet passage for the chamber.

In prior devices a single accumulator valve has been used in controlling the flow of fuel into and out of the accumulator chamber. This valve is normally held by the pressure of fluid in the in let to the chamber in such a position that fuel will not discharge from the chamber and a drop in pressure in the inlet causes the valve to move for a discharge of fuel. For high speed operation this valve must have the characteristics of rapidly opening and closing and must also provide for a high flow rate in order that the discharge of fuel from the chamber through the nozzle may occur in the desired short space of time. A feature of the invention is the use of two separate valve devices, one of which will control the flow into the chamber and the other will control the discharge from the chamber. By this arrangement it is possible to obtain the desired characteristics in each of the valves.

Another object of the invention is an arrangement by which the valves may be located in a valve body which can be readily machined separate from the ring of the device.

Another feature is the arrangement of the discharge valve so that it is held closed by pressure in the inlet passage for the chambers and is opened by a pressure drop in the inlet passage supplemented by a spring to make the operation more positive.

In addition to the pressure control discharge valve it has been found that a. check valve is advantageous in the discharge so that the flow from the chambers will terminate at a predetermined pressure. A feature of the invention is a control for a check valve in the discharge ring which has a limited lift so that its rate of closing may be rapid. Another feature is a control for the lift of both the inlet check valve and the pressure actuated valve.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a sectional view through the device.

Fig. 2 is a sectional view through a modified form of the device.

As shown in Fig. 1 a casing has a bore l2 in which a plunger l4 reciprocates. An inlet Eli - 2 ciprocatlon ior admitting fuel to the bore and a vent port I8 is uncovered by a groove 20 in the plunger for venting the space at the head of the plunger. Groove 20 is connected with the head of the plunger by passages 22 and 24.

Fuel is accumulated in chambers 26 in the casing being pumped through an inlet passage 28 in a valve body 30. A check valve 32 engages a seat 34 in the passage and is held in position by a spring 36. A plug 38 engages the valve as it opens and limits the extent of valve opening. As shown, valve 32 has an extremely small mass so that it will open and close rapidly. Thus, when the space at the head of the plunger is vented the valve 32 will close quickly and no substantial amount of fuel will flow out of the chambers. The chambers communicate with each other by a cylindrical space 40 surrounding the valve'body 3t.

Fuel in the chambers discharges through a passage 42 in the valve body and past a check valve 44 in a ring it through a discharge passage 48 in a nozzle it. A pressure actuated valve 52 controls the flow through passage d2.

Valve 52 reciprocates in a bore es and is nor= mally moved into open position by a spring 58. The valve has a conical tip engaging a seat 58 and at the other end forms a plunger reciprocating in bore 55. This bore communicates with the space at the end of the pump plunger through a passage 60 in a plate 62 so-that pressure at the end of thepump plunger may act on the valve 52 and hold it closed whil fuel is being forced under pressure into the chambers.

The ring 46 has a central passage 63 having a seat 64 at its upper end engageable by the port it is uncovered by the plunger during re check valve 44, the latter being held against the seat by a coil spring 66. A bar 68 having a head ill with grooves 12 is supported within the spring in a position to limit the opening of valve M.

The grooves 12 permit fuel to flow past the head and through the discharge passage it.

Plate 62, valve body 30, ring 46 and nozzle 56 are all clamped within the casing by a clamping ring 14. As shown, this ring engages gaskets it resting against a conical surface 18 on the nozzle. The nozzle'and the ring 46 are held against relative rotation by a pin and the lower end of ring 46 engages the valve body. By this arrangement, the valve body, with the seats formed therein, and the valves also mounted therein, may be assembled within the casing structure and beheld within the casing by the same clamping ring that holds the nozzle.

In operation, with the plunger in the position shown and moving upwardly on the pumping stroke, fuel continues to be forced into the chambers 26 until passage I8 is uncovered. When this occurs, valve 32 is closed by spring 36 and the drop in the pressure at the head of the plunger resulting from the uncovering of port I8 causes the pressure actuated valve to move down until it engages plate 62, this latter plate limiting the opening of the valve. The pressure actuated valve may be dimensioned to assure an adequate rate of flow from the chambers either by controlling the lift or the seat area.

With the pressure actuated valve open fuel accumulated in the chambers discharges through passage 42 past the check valve 44 which is opened by the fuel pressure and through groove I2 to be discharged through passage 40.

As the plunger begins its downward stroke valve 34 remains seated and fluid connection between the chambers and the space at the head of the plunger is cut off by the plunger part of the pressure actuated valve. After port I6 is uncovered the space at the head of the plunger fills and the plunger begins its upward movement for again forcing fuel into the plungers.

By the arrangement shown, the accurate machine work required on the casing I is minimized. being limited to the bore I2, the larger bore 82 which guides the nozzle 50 and ring 46, and the surface 84 with which plate 62 engages.

With reference to Fig. 2, the casing 86 has a bore 88 in which a plunger 90 reciorocates. An inlet port 92 is uncovered by the plunger during reciprocation for admitting fuel to the bore and a vent port 94 is uncovered by a groove 96 in the plunger as the latter reaches the upper end of its stroke for ventin the space 08 at the head of the plunger. Groove 96 is connected with the head of a lunger by a passage I00 and a cross passage I02. I

Fuel is accumulated in an annular chamber I04 in the casing, being pumped through an inlet passage I06 in valve body I08. A check valve IIO en ages a seat in the passage and is held in posit on by a spring I I2. The valve H0 is similar to valve 32 and has an extremely small mass. A lateral port I I4 in the valve body I 08 connects the check valve with the annular chamber I04.

Fuel from the chamber I04 discharges through a port IIS into a bore H0 in the valve body and past a valve I20 into a passage I22 in the valve body and an ali ned passa e I24 in the nozzle bodv I26. A check' valve I28 adjacent the end of passage I24 terminates the discharge of fuel through apassage I30 in a nozzle tip I32 when the pressure in passage I 24 is reduced to a predetermined amount;

Valve I20 has an integral plunger I32 which is exposed to the pressure in space 98 by a communicating passage I34 in a plate I36 which also limits the lift of valve I20. Thus, with a drop in pressure in space 98 the spring I38 assisted by the pressure within bore II8 moves the plunger I32 down to open valve I20.

Check valve I 28 is located adjacent to the passage I30 to minimize the space between the check valve and the end of the passage, thereby reducing the amount of fuel that will dribble from the passage after the check valve closes. As shown, the check valve engages a seat I40 in a ring I42 located within the nozzle tip I32. A coil spring I44 holds the check valve closed and the ring is held in place by the tip which may be threaded to cooperate with corresponding threads on the nozzle body.

In assembly of the device, the plate I30 and the valve body I08 with the valves therein may be placed in position with a pin I40 located in the bore I48 for check valve I I 0 projecting beyond the end of the bore to index a plate I 50 having a passage I52 in line with passage I22 and also to index the nozzle body I26. A threaded clamping ring I54 engages packing I55 for sealing the device and for holding the assembled elements within the casing.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

plunger, a casing having a bore in which the plunger reciprocates, a chamber into which fuel is pumped and in which fuel is accumulated under pressure, a discharge passage from the chamber, a connection from the chamber to the bore, a valve body through which said connection is made and through which the discharge passage extends, said casing having a recess for the valve body, a check valve positioned in said body and located in the connection between the chamber and the bore, and a pressure actuated valve mounted in said valve body and located in the discharge passage, and means for holding said body in the casing.

2. A fuel injection system including a pump plunger, a casing having a bore in which the plunger reciprocates, a chamber into which fuel is pumped and in which fuel is accumulated under pressure, a discharge passage from the chamber, a connection from the chamber to the bore, a valve body through which said connection is made, said casing having a recess for the valve body, a check valve positioned in said body and located in the connection between the chamber and the bore, a pressure actuated valve mounted in said valve body and located in the discharge passage, and means for holding said body in the casing.

3. A fuel injection system including a pump plunger, a casing having a bore in which the plunger reciprocates, a chamber into which fuel is pumped and in which fuel is accumulated under pressure, a discharge passage from the chamber, a connection from the chamber to the bore, a valve body through which said connection is made and through which the discharge passage extends, said casing having a recess for the valve body, a check valve positioned in said body and located in the connection between the chamber and the bore, a pressure actuated valve mounted in said valve body and located in the discharge passage, and means for holding said body in the casing including a ring for holding the valve body in position.

4. A fuel injection system including a casing having an inlet passage, a chamber in which fuel is accumulated under pressure, a connection from said passage to said chamber, a check valve in said connection to prevent flow of fuel from the chamber to the passage, a discharge passage from the chamber, and a pressure actuated valve in said last passage, said pressure actuated valve including a plunger, a cylinder in which the plunger slides, and a connection between said cylinder and said inlet passage to cause said valve to move in response to changes in pressure in said inlet passage.

5. A fuel injection system including a casing having an inlet passage, a chamber in which fuel is accumulated under pressure, a connection from said passage to said chamber, a. check valve in said connection to prevent flow of fuel from the chamber to the passage, a discharge passage from the chamber, and a pressure actuated valve in said passage, said pressure actuated valve including a plunger, a cylinder in which the plunger slides, a connection between said cylinder and said inlet passage to cause said valve to move in response to changes in pressure in said inlet passage. and a spring acting on said pressure actuated valve for opening it.

6. A fuel injection system including a casing having an inlet passage, a chamber in which fuel is accumulated under pressure, a connection from said passage to said chamber, and a discharge passage from the chamber, in combination with a valve body through which said fuel connection is made and through which the discharge passage extends, said casing having a recess for the valve body, a check valve located in the valve body in the connection from the inlet passage to the chamber, a pressure actuated valve located in the discharge passage and positioned in the valve body, and means for holding said body in the casing.

7. A fuel injection system including a casing having an inlet passage, a chamber in which fuel is accumulated under pressure, a connection from said passage to said chamber, and discharge passage from the chamber, in combination with a valve body through which said fuel connections are made, said casing having a recess for the valve body, a check valve located in the valve body in the connection from the inlet passage to the chamber, a pressure actuated valve located in the discharge passage and positioned in the valve body, said valve body having a fluid connection between the inlet passage and the pressure actuated valve to cause said valve to move in response to changes in pressure in said inlet passage, and means for holding said body in the casing.

8. A fuel injection system including a plunger, a casing having a bore in which the plunger resaid pressure actuated valve having associated therewith a plunger, a cylinder within which said plunger is slidable, and a connection from the cylinder to said bore so arranged that pressure from said bore transmitted to said chamber will hold said pressure actuated valve closed and a drop in pressure in said bore will allow the pressure actuated valve to be opened by the pressure in said chamber.

DONALD E. MEITZLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 415,497 Cavallaro Nov. 19, 1889 1,553,768 Gleason Sept. 15, 1925 1,585,277 Bell May 18, 1926 1,701,089 Von Salis Feb. 5, 1929 1,707,912 Heindorf Apr. 2, 1929 1,967,987 Broege July 24, 1934 2,075,949 Lemon Apr. 6, 1937 2,121,102 Scott June 21, 1938 2,147,031 Hastings et a1. Feb. 14, 1939 2,283,725 Eichelberg May 19, 1942 2,380,148 Camner July 10, 1945 2,420,431 Kalitinsky May 13, 1947 2,420,432 Kalitinsky May 13, 1947 FOREIGN PATENTS Number Country Date 146,072 Switzerland Mar. 31, 1931 491,150 Germany Jan. 23, 1930

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