US2317618A - Fuel injector - Google Patents

Description

April 27, 1943. l F. R. KING FUEL INJECTOR Filed Dec. 23, 1940 1 y?? 7/ QZ/f 24 wwwa Patented Apr. 27, 1943 UNITED STATES PATENT OFFICE FUEL INJECTOR Franklin King, Yelm, Wash. Application December 23, 1940, Serial No. 371,452 2 claims. (c1. a99-107.2)

'I'his invention relates to a fuel injector and more particularly to a cylindrical valve fuel injector for Diesel engines, it being one object of the invention to provide a fuel injector which is automatically adjusted in response to variations in engine speed and resulting pressures, thus causing flow of fuel to the engine to be automatically. increased as engine speed increases and the proper quantity of fuel delivered in accordance with the speed of the engine.

Another object of the invention is to provide a fuel injector wherein the fueljis delivered to the nozzle of the injector through a hollow valve which is yieldably held against sliding movement in one direction and urged in this direction by pressure of the fuel oil so that as engine speed increases and pressure von the fuel also increases, ports of the valve will be progressively and successively moved into registry with discharge ports of the injector to permit progressive increase in the quantity of fuel discharged from the injector.

Another object of the invention is to provide a fuel injector of such construction that u'nder certain conditions fuel under pressure may return to the place of origin by movement through a bypass formed in the injector.

Another object of the invention is to provide a fuel injector which is simple in construction and capable of being easily taken apart and reassembled when cleaning or repair is necessary.

In the accompanying drawing:

Fig. 1 is a sectional view taken longitudinally through the improved fuel injector, the upper portion of the injector being broken off and the valve being in its initial position.

Fig. 2 is a sectional view taken longitudinally through the lower portion of the injector with the valve shifted to low speed position.

Fig. 3 is a view similar to Fig. 2, with the valve in position for second speed.

Fig. 4 is a view similar to Fig. 3; with the valve set for high speed.

Fig. 5 is a sectional view taken transversely through the nozzle of the injector, on the line 5-5 of Fig. 1.

This improved fuel injector has a cylindrica body I which may be of any desired length and leads from a suitable source of fuel under pressure, the pressure being supplied in a conventional manner by the Diesel engine to which the fuel is delivered. The lower end of the body I is reduced to form a shank 2 which isexternally threaded and engages in the internally threaded socket 3 of a nozzle 4. 'I'he main chamber 5 of the body I extends to adjacent the lower end thereof and the shank 2 is formed with a bore 6 leading from the front end of the chamber 5. A channel I extends longitudinally of the chamber 5 at one side thereof and, at the opposite side of the chamber from the channel I are channels 8 and 9 which terminate in spaced relation to each other and are connected by a shallow groove or air Vent I0.

The nozzle 4 is closed at its lower end and about its circumference is formed with spaced orices or outlet ports which become active in a certain order to be hereinafter explained and which, for convenience, have been designated as Ila, IIb, and IIc. These orifices or ports constitute terminals for lower ends of conduits I2 formed in a liner I3 longitudinally thereof, and attention is called to the fact that the conduits leading to the ports IIb are longer than those leading to thcports IIc but shorter than the conduit leading to the port IIa. It is also to be noted that the conduits have inlet openings I4 leading from their upper ends, the conduit leading from the port IIa being provided with a second opening I4a spaced downwardly from its inlet I4. A key I5, which is-driven into registering notches, holds the liner stationary and prevents it from turning in the nozzle.

A pressure controlled valve I6 loperates in the body and the nozzle and has a cylindrical upper portion from which extends a tube Il of a diameter adapting it to fit snugly in the bore 6 and the liner I3. The bore I8 of this tube leads from the lower end of the chamber I9 defined by the cylindrical upper portion of the valve and in spaced relation to its lower end the tube is formed with outlet openings 20 communicating with external' recesses 2| of such dimensions that they may register with the inlet openings of the conduits I2 in a manner to be hereinafter set forth.

A spring 22 which is seated in the lower end of chamber 5, urges the valve upwardly and normally holds it in the position shown in Fig. 1, with its upper end abutting the lower end of a sleeve 23 which fits snugly in the body I. This sleeve is plugged by a core or plunger 24 having passages 25 and 26 formed longitudinally therein from its lower end and having their upper ends registering with openings 2l and 28 formed through opposite side portions of the sleeve and communicating with the oil passages 'I and 8. 'Ihe core 24 is a vertically disposed pump plunger or piston of the type shown in Patents Nos.`

2,082,808; 2,096,711; and 2,144,862, and is driven takes piace until the port 21 is again uncovered by the portion 2lb of the groove moving into registry with the port. Since the portion 2lb of the groove 24a has a curved side wall, turning of the plunger to adjusted positions will regulate the time required for uncovering of the port 21 during downward movement of the plunger. The passage 2l is of greater diameter than the passage 26 and, referring to Fig. 1, it will be seen that the lower portion of the core engages in the chamber I9 of the valve IBso that during operation of the injector, the fuel may ow from pasl sage I downwardly through passage 25 into the chamber I8 and a portion of this fuel flows through the bore I8 of tube I'I while surplus fuel enters passage 2,6 and flows upwardly through the same and through the passage 8 back to the source of supply. The vent I0, which establishes Aommunication between the passages 8 and 9, allows air to escape and thus prevent the formation of an air cushion or the accumulation of oil under pressure in the lower portion'of chamber 5, which would prevent proper reciprocating movement of the valve.

When this fuel injector is in use, it is mounted in a conventional manner with its nozzle within the cylinder or casing of a Diesel engine. In the initial position of the valve, the side ports 2l of the stem are located above the side ports Il of the liner and fuel cannot enter the conduits I2. If the fuel is under pressure, it will enter the chamber I9 from passage 25 and then leave by way of passage 26 and return to the source of supply. When the engine is in operation and pressure forces the valve downwardly to the position shown in Fig. 2, the recess registers with the port Il of the conduit leading to the outlet IIa, and fuel will be discharged from this outlet for operation of the motor at low speed. When the throttle is opened wider the increased pressure again forces the valve downward and the recess will register with the side port Ma and, at the same time, register with the inlets of the conduits leading to the outlets IIb and fuel will be disarged from these outlets as well as from the outlet IIa. l 'I'his is shown in Fig. 3. The pressure is again increased when the throttle is fully opened for high speed operation of the motor, and the valve will then be shifted downwardly to the position shown in Fig. 4. 'I'he recess will then register with the inlets of all of the conduits and fuel will be discharged from the outlets IIc in addition to the outlets I Ia and IIb. It will thus be seen that the valve will be successively moved into position to deliver fuel to first the outlet I Ia,

then to the outlets Ila and I ib, and then to the outlets IIa, I Ib and I Ic, and the quantity of fuel delivered will be progressively increased and sumcient fuel delivered to the engine at all times. When the engine is shut oii, the spring 22 returns the valve to its initial position and the now of fuel will be stopped, it being understood that if the throttle is actuated to merely reduce the speed of the engine, instead of shutting it oi! entirely, the quantity of fuel will be reduced proportionately. At all times, surplus fuel will be returned to the source of supply through the passage 26.

Having thus described the invention, what is claimed is:

1. A pressure controlled fuel injector comprising a tubular body having a main chamber and a bore leading from the chamber through the discharge end of the body, a nozzle carried by and extending from the discharge end of said body and having a head at its outer end and discharge ports spaced from each other circumferentially of the nozzle, a liner for the nozzle formed with external grooves extending longitudinally thereof and constituting conduits having their forward ends registering with the ports of the nozzle and their rear ends communicating with inlet openings extending through the walls of the liner, a pressure actuated valve having a hollow cylinder slidable longitudinally in the body and a tubular stem extending forwardly from the cylinder and slidably passing through the bore of the body into the liner, said stem having side ports for registering with the inlet openings of the conduits as the valve is shifted forwardly, and spring means yieldably resisting forward movement of the valve.

2. A pressure controlled fuel injector comprising a tubular body having a main chamber and a bore leading from the chamber through the discharge end of the body, a nozzle carried by and extending from the vdischarge end of said body and having a head at its outer end and discharge ports spaced from each other circumferentially of the nozzle, a liner for the nozzle formed with external grooves extending longitudinally thereof and constituting conduits having their forward ends registering with the ports of the nozzle and their rear ends communicating with inlet openings extending through the walls of the liner, certain of said conduits extending rearwardly along the liner beyond rear ends of other conduits and one of the elongated conduits having its rear end portion communicating with front and rear inlet openings spaced from each other longitudinally cf the liner, a tubular pressure actuated valve slidable longitudinally in the body and including a tubular stern slidable longitudinally in the liner and formed with outlet openings through its sides terminating in grooves extending longitudinally of the stem externally thereof in position to successively register with the inlet openings of the conduits as the valve is shifted forwardly, and spring means for yieldably resisting forward movement of the valve.

FRANICLIN R. KING.

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