US2730342A - Fuel injector - Google Patents

Description

Jan. l0, 1956 Filed Sept. 19, 1951 R. C. LEE

FUEL INJECTOR 2 Sheets-Sheet 1 `lan.. 10, 1956 2 Sheets-Sheet 2 Filed Sept. 19, 1951 III m w w ,j 1 y A d 4M Mv cu M 1/3 @91 w |l|- M ML JNVENTOR. Ray f. ec

FUEL INJECTOR Roy C. Lee, Irvington,N. I. Application September 19, 1951,*Serial No. 247,231 1 Claim. (Cl. 261,-.-4-1) This invention relates to a fuel injector and it is one object of the invention to provide a fuel injector having an improved arrangement of valves for controlling delivery of liquid fuel into the mixing chamber of the fuel injector, the valves being so arranged that as the speed of the engine to which the fuel injector is applied is increased the quantity of fue! delivered will be automatically increased and likewise reduced when the speed of the engine is reduced.

Another object of the invention is to cause ow of liquid fuel through a plurality of valves to be successively started and also successively cut off in accordance with the speed of the engine without adjustment of the valves and thus eliminate moving parts which would be yliable to become stuck and interfere with proper operation yof the fuel injector.

Another object of the invention is to provide a fuel injector wherein liquid fuel is delivered from a supply pipe into a chamber or reservoir and thus create a supply of fuel which is withdrawn from the chamber as the engine speed is increased from idling or low speed to intermediate speed and then to high speed.

Another object of the invention is to provide means for preventing overflowing of fuel from the supply chamber and thus prevent the fuel injector from becoming flooded.

Still another object of the invention is to provide a fuel injector having a small mixing chamber through which a portion of the fuel passes before reaching the main mixing chamber and thus provide a sufficient quantity of mixed fuel and air for operation of the engine at idling speed.

A further object of the invention is to provide a fuel injector which is simple in construction and may be very accurately set.

The invention is illustrated in the accompanying drawings, wherein;

Figure l is a view looking down upon the improved fuel injector from one side thereof;

Figure 2 is a View looking at the right side of the fuel injector with portions shown in section along the line 2-2 of Figure 1;

Figure 3 is a view similar to Figure l, but loo-king down upon the fuel injector from the other side thereof;

Figure 4 is a view looking at the left side of the fuel injector, the View Vbeing taken along the line 4-4 of Figure 3.

Figure 5 is a vertical sectional view taken along the line S-S of Figure 4; and 4 Figure 6 is a fragmentary view in elevation, looking towards outer ends of the valves controlling flow of liqid fuel.

With continued reference to the drawing the fuel injector of this invention may well include an elongated vertically disposed hollow body 1, providing interiorly thereof a primary mixing chamber 2. Air` may ilow downwardly from an inlet chamber 4 communicating with 2,730,342 Patented Jan. 10, `1956 a conventional air cleaner and silencer and through a throat l3 and into the mixing chamber 2, to belmixed with fuel in a manner to be presently described. Flow of `air through the primary mixing chamber 2 may be controlled by a conventional butterfly throttle valve 5' mounted on a shaft 5 provided with an actuating lever 6. The fuel mixture flows downwardly from the primary mixing chamber 2 into the conventional intake manifold of an internal combustion engine.

A fuel chamber 7 is mounted vertically adjacent the lower portion of the body in parallel relation thereto and betweenthis chamber and lthe body is an auxiliary mixing chamber S from which extends an upwardly projecting air inlet tube 9 having its upper portion bent transversely and entering the primary mixing chamber 2 and spaced downwardly from the throat 3 above the throttle valve 5. The auxiliary mixing chamber 8 communicates with the primary mixing chamber 2 below the throttle valve 5 through a jet 8. The upper end or top of the fuel chamber 7 is closed by a cap 16 which serves as a support for valves 11, 12 and 13. The valve 11 controls flow of liquid fuel to the auxiliary chamber 8 at idling or low speed, the valve 12 is a medium speed valve, and valve 13 is a high speed valve. A nipple 14 which is passed upwardly through the cap 10 firmly secures the valve 1l in place upon the cap and at its upper end, the nipple is formed with a small opening or perforation i5 adapted to be closed by a needle 16 which is slidable vertically in the bore 17 of the nipple and having a downwardly extending stem i8.

The lower end of the stem 18 rests upon a float 19 housed in the chamber 7 and movable vertically therein in response to variations in the level of liquid fuel in the chamber. A fuel supply pipe is connected with the valve 11 by a nipple 2l screwed to an opening 22 formed through a side portion of the valve and a portion of the incoming liquid fuel flows through the bore 17 of the nipple 14 and into the fuel chamber 7. As the quantity of fuel in the chamber increases, the float rises until the upper surface of the iloat engages the lower end of the stem 1S and moves the needle 16 upwardly to a closed position. A fuel feeding tube 23 extends from the front end of the valve 11 and downwardly therefrom and has its lower end portion bent inwardly and communicating with a side opening formed in the auxiliary chamber 8. A needle 24 which is screwed into the valve 11 through the rear end thereof, and has a turning head 25 at its rear end, extends longitudinally in the bore 26 of the valve 11 and when this needle is screwed inwardly its full extent, flow of fuel through the reduced front end portion 27 of the bore will be shut off and iiow of fuel through tube Z3 prevented when so desired. By properly adjusting the needle 24, ilow of fuel to auxiliary mixing chamber S sufficient for idling and low speed will be permitted.

The valve 12 at the left side of the fuel injector supplies liquid fuel by syphon action to auxiliary mixing chamber 8 for intermediate speed and is similar in construction to the valve 1l. This valve is secured upon the cap l0 by a nipple 28, corresponding to the nipple 14, and from its front end extends a fuel feeding tube 29 corresponding to tube 2.3 and extending downwardly and having its lower end portion bent inwardly and extending into the auxiliary chamber ZB through the opposite side thereof from the tube 23. The nipple 2.3 differs from the nipple ifi in that it is not provided with a needle corresponding to needle 16. This nipple 2S carries an inlet tube 30 which extends downwardly there- 0 from in the chamber 7 and through an opening 3l formed vertically through the oat and has its lower end disposed near the bottom of the chamber 7 so that fuel may be drawn upwardly through the tube 30 into the bore 31 of the valve 12 through which it flows into the tube 29. A needle 32 having a turning head 33 at its rear end controls flow of fuel through this valve and its tube 29 into the auxiliary chamber 8. When the engine is idling or running at low speed, fuel is only delivered through the valve 11, but when the speed of the engine is increased, suction draws fuel from the chamber 7 through tube 30, so that it is delivered through tube 29 into the auxiliary mixing chamber 8 and a greater quantity of fuel is thus supplied to the primary mixing chamber 2 to compensate for the increased ow of air into primary chamber 2.

When the engine is running at high speed, a still greater quantity of liquid fuel is needed. This additional fuel is obtained by syphon action through the high speed valve 13 and delivered directly into the primary mixing chamber 2 through an inlet nipple or high speed jet 34 instead of through the auxiliary chamber 8. This valve 13 is mounted upon a carriage or cradle 35 which is slidable along a track or bracket 36 projecting from the body 1. A feed tube 37 extends downwardly from the valve 13 and through an opening 38 formed vertically through the center of the float 19 so that liquid fuel may be drawn upwardly through this tube into the bore 39 of the valve from which the fuel passes into the nipple 34. A needle 40 having a turning head 41 at its rear end is screwed into the bore of the valve 13 and controls the quantity of fuel delivered from the valve. An adjusting screw 42 which is threaded longitudinally through the carriage 35 and swiveled at its front end to the attached end 36' of the track 36 is provided for shifting the carriage and the valve longitudinally along the track and thus move the valve towards or away from the nipple 34 and allow a desired quantity of air to be drawn inwardly through the nipple and mix with liquid fuel. An auxiliary supply of atomized fuel is thus delivered into the throat 3 of the body and mixed with the air passing downwardly through the primary mixing chamber 2 of the fuel injector.

The fuel injector of this invention, as described above, operates very efficiently to supply fuel to the primary mixing chamber 2 at low, intermediate and high speeds. With the throttle valve 5' in closed position, as shown in dotted lines in Fig. 2, the relatively high vacuum below the throttle valve 5 induces a vacuum in the auxiliary mixing chamber 8 through the low and intermediate speed jet 8 and since the auxiliary mixing chamber 8 communicates with the primary mixing chamber 2 above the throttle valve 5' through the air inlet tube 9, air is drawn through such tube 9 to substantially destroy the vacuum in auxiliary mixing chamber 8.

When the engine is running at idling speed, fuel under pressure is supplied through the valve 11 and fuel feeding tube 23 to the auxiliary mixing chamber 8, where the same is mixed with air supplied through the air inlet tube 9 and discharged into the primary mixing chamber 2 below the throttle valve 5 through the low and intermediate speed jet 8'. It is to be noted, that even though under these conditions, there is substantially no vacuum present in the auxiliary mixing chamber 8, fuel will be `supplied to such mixing chamber, due to the fact, that the fuel is supplied under pressure from the fuel pump to the valve 11 and is conducted directly to the auxiliary mixing chamber 8 through the fuel feeding tube 23. At the same time, the oat valve 16 operates to maintain a pre-determined level of fuel in the fuel chamber 7.

The auxiliary mixing chamber S also communicates through a fuel feeding tube 29, valve 12 and tube 30 with the fuel chamber 7, but since, under idling conditions, there is substantially no vacuum present in the auxiliary mixing chamber 8, fuel will not flow thereto through the fuel feeding tube 29, since flow through such tube results from a siphon action induced by a vacuum in the auxiliary mixing chamber 8. Consequently, the sole fuel supply during idling conditions is under pressure from the valve 11 through the fuel feeding tube 23 to the auxiliary mixing chamber 8 and through the low and intermediate speed jet 8 into the primary mixing chamber 2.

As the throttle valve 5 is opened to increase the engine speed to an intermediate range, the ow of air into and through the primary mixing chamber 2 will increase thereby reducing the vacuum below the throttle valve 5 and the velocity of such air will, at the same time, induce a vacuum in the auxiliary mixing chamber 8 through the air inlet tube 9. As a consequence, during intermediate speed conditions, there will be a sufficient vacuum present in the auxiliary mixing chamber 8 to create a Siphon action in the fuel feeding tube 29 and tube 30, resulting in ow of fuel from the fuel chamber 7 through the tube 30, the valve 12, fuel feeding tube 29 and into the auxiliary mixing chamber 8. This fuel is in addition to that being supplied under pressure through the fuel feeding tube 23 from the valve 11.

The quantity of fuel delivered from the valve 11 to the auxiliary mixing chamber 8 is controlled by the needle valve 24 having a finger engaging knob 25 and the quantity of fuel delivered to the auxiliary mixing chamber 8 through the fuel feeding tube 29 from the valve 12 is controlled by a needle valve 32 having a finger engaging knob 33. Thus, for idling and intermediate speeds, the fuel for forming a combustible mixture in the primary mixing chamber 2 is supplied through the low and intermediate speed jet 8' from the auxiliary mixing chamber S, the fuel being supplied through the fuel feeding tube 23 at idling speed and through this tube and the fuel feeding tube 29 at intermediate speed.

As throttle valve 5' is opened to the high speed range, the vacuum exerted on low speed jet 8 decreases and, at the same time, the vacuum exerted on the high speed jet 34 increases and consequently, fuel is supplied to the primary mixing chamber 2 in the high speed range from the valve 13 through the high speed jet 34. The quantity of this fuel is controlled by a needle valve 40 having a finger engaging knob 41 and furthermore, this fuel is atomized and mixed with air prior to entry into the jet 34, the quantity of air mixing with the atomized fuel flowing through high speed jet 34 being determined by the horizontal position of valve 13 relative to high speed jet 34, this position being controlled by the adjusting screw 42.

As the throttle valve 5' is moved toward closed position, the vacuum exerted on high speed jet 34 will decrease while the vacuum exerted on low speed jet 8 will increase and this low speed jet will gradually take over the operation of supplying a combustible mixture to the primary mixing chamber 2 until idling speed is again reached where the operation will be as described above.

It is to be noted, that the auxiliary mixing chamber 8 provides for a pre-mixing of the fuel with the air prior to introduction of the same into the primary mixing chamber 2 thus providing a better dispersion of the fuel particles in the air and promoting higher etiiciency of the internal combustion engine supplied with a combustible mixture by the fuel injector of this invention.

From the foregoing description of my improved fuel injector, the construction and operation thereof will be readily understood and it will be seen that I have provided a comparatively simple, inexpensive and efficient means for carrying out the various objects of the invention.

While I have particularly described the elements best adapted to perform the functions set forth, it is apparent that various changes in form, proportion and in the minor details of construction may be resorted to, without departing froml the spirit or sacrilicing any of the principles of the invention.

Having thus described my invention, what is claimed 1s:

A downdraft fuel injector for internal combustion engines comprising an elongated hollow body providing a primary mixing chamber, a throttle valve in said primary mixing chamber, an auxiliary mixing chamber communicating with said primary mixing chamber through a low and intermediate speed jet disposed below said throttle valve, an air inlet tube communicating with said auxiliary mixing chamber and with said primary mixing chamber above said throttle valve, a fuel chamber secured to said body, a fitting communicating with said auxiliary mixing chamber and said fuel chamber, a fuel inlet in said fitting for receiving fuel under pressure, a low speed valve for controlling flow of fuel under pressure from said fitting to said auxiliary mixing chamber, a float valve in said fitting, a float in said fuel chamber for actuating said oat valve to control flow of fuel from said fitting to said fuel chamber, a second fitting communicating with said auxiliary mixing chamber and the lower portion of said fuel chamber, an intermediate speed valve for controlling iiow of fuel from said fuel chamber to said auxiliary mixing chamber, a high speed jet communicating with said primary mixing chamber above said throttle valve, means for supplying fuel from said fuel chamber to said high speed jet and a high speed valve for controlling iiow of fuel to said high speed jet whereby with said throttle valve closed or partially open air will be drawn into said auxiliary mixing chamber through said air inlet tube and mixed with fuel supplied from said first fitting at low speed and from said first fitting and said second fitting at intermediate speed to discharge a combustible mixture at low and intermediate speed jet into said primary mixing chamber, said high speed jet Serving to spread fuel to said primary mixing chamber at high speed.

References Cited in the file of this patent UNITED STATES PATENTS 1,444,222 Trego Feb. 6, 1923 1,753,235 Du Apr. 8, 1930 1,956,992 Mallory May l, 1934

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