US1819706A - Carburetor - Google Patents

Description

E. F. GEIGER Aug. 18, 1931.

cmaunmon Filed March 27, 1928 Patented Aug. 18, 1931 EDWARD r. GEIGER,OF IBINGHAIMTON, NEW YORK CARIBURETOR' Application filed March'27, 1928. Serial No. 265,133.

The present invention relates to improvements in carburetors and more particularly relates to a provision of a carburetor which is adapted to provide an automobile engine with the proper quality of fuel mixture at various and all engine speeds and when the engine operates under different power requirements.

More particularly the present invention relates to an improvement and modification of the carburetor disclosed in my copending applications, Serial No. 105,668, filed April 30, 1926 and Serial No. 17 6,097 filed March 17, 1927. I

According to the present invention the quality of the fuel mixture is controlled primarily by the degreeof throttle opening and secondarily by the air speed through the carburetor, so that for low air speeds the mixture will be rich or lean depending upon the extent to which the throttle is opened and with widely open throttle conditions the mixture will be rich or lean dependin upon whether the air speed is low or high. buch ultimately desired results while heretofore obtained with my former constructions necessitated the use of supplementary movable auxiliary valve means which, according to the present invention are dispensed with.

The present invention provides a novel cooperation of parts including a venturi disposed in a. novel manner which parts and .vcnturi cooperate to produce the desired quality of mixture under-varying conditions of engine operation.

Further objects and advantages will be hereinafter set forth in the accompanying specification and claims shown in the drawings, which by wa of illustration show what I now consider to be a preferred embodiment of the invention.

In t 1e drawings:

Figure 1 shows substantially a central vertical sectional view of my carburetor with a sectionalized.

Fig. 2 is a large sectional detail View like Fig. 1 showing the aforesaid tube in central section.

the upper part of 11. certain tube therein shown in full and not Fig. 3 is a detail end view taken on line 3-3 of Fig. 1.

The carburetor comprises the usual well known parts such as manifold-connection 1 having associated therewith a mixture con- 65 duit 2 provided with a throttle valve 3 0perated in the usual manner. This valve 3 has certain novel features of construction which will be hereinafter described The carburetor also includes a convention al constant level float chamber 4 which is supplied with fuel through pipe 5, the flow of fuel being controlled by float valve 4a.

There is furthermore provided an air inlet conduit 6, extending below the throttle and provided with the usual choke Valve 7. Disposed in the conduit 6 intermediate the choke 7 and the extended portion 2a of the mixture conduit 2 at a point below the throttle 3, is a venturi 8 which serves as will hereinafter be described.

Extending substantially centrally through the float chamber 4 is a uel well 9 having a tubular outer wall 9a. This fuel well 9 is supplied with fuel from the float chamber through a calibrated orifice 10. Within the tube 9a is a tubular conduit 11 provided with a plurality of calibrated passages 12 through its wall, which passages establish communication between the fuel well 9 and a space inside of conduit 11. Extending into conduit 11 and closing its lower end preferably by being press fitted therein is another conduit 13. This conduit is open at both ends and serves to conduct air into conduit 11 at a point above the normal level of the fuel therein as shown in Fig. 2. The throttlevalve 3 is slotted as shown at 14, this slot affording an opening from the space 2 to the space 2a below the throttle. A screw adjustment 15 is provided adaptable to be manually manipulated for setting the total effective area of the opening or slot 14. A conduit 16 forms a continuation of conduit 11 and closely fits The conduit 16 extends up towards and al" most reaches the throttle valve 3 when the latter is ina nearly closed position as shown in Fig. 1. The upper end of conduit 16 is fur thermore shaped or bevelled to substantially a special purpose 70 shown. The throat of the Venturi section 8 is in communication with the fuel well 9 at a point above the normal fuel level. Such communication is afforded by passages 17 annular chamber 18, passage 19 and chamber 20. Chamber 20 furthermore can be connected to atmosphere. An opening 21 is provided in the wall of chamber 20 and a screw adjustment 22 is provided which can be set to any desired position to vary the total effective area of opening 21. The Various parts and passages 16, 13, 21, 20 and 9?) all constitute auxiliary air passages and conduits for supplying air additionally to that supplied through the main air conduit 6. All of such auxiliary air finally enters the mixing chamber through conduit 16.

In operation, the action of the carburetor is different with different degrees of throttle opening. \Vhen the throttle is in a nearly closed position the suction of the engine produces a considerable depression or lowering of the pressure in the mixture conduit 2 above the throttle. There is, accordingly, a resultant high air speed through the opening 14. Due to the location and arrangement of conduit 16 this high air speed brings about a depression of pressure within conduit 16. the effect of which is to produce a rush of air up through conduit 13, through 11 and into 16. A pressure differential is also created between the inside of tube 11 and the space 9?) outside of such tube. This pressure differential causes air to pass through the upper openings 12 above the fuel level in well 9 into the interior of tube 11. The pressure differential will also cause fuel to flow through the lower submerged openings 12 into 11. As such fuel flow proceeds through these openings, the withdrawal of fuel will cause the level of the fuel in well 9 to fall uncovering more of the openings 12 and causing the air passing through such uncovered openings to mix with the fuel in annular space 30. This fuel or mixture upon passing upwardly beyond the top of tube 13 becomes commingled and atomized with the air which flows up through 13. The atomized fuel and air is carried along through conduit 11 through 16 and opening 14 into the mixture chamber 2 where the mixture is commingled with any air which may pass the edges of the throttle provided the throttle is very slightly opened. In this way the fuel mixture is formed for the engine when the latter is idling or running with a nearly closed throttle.

As previously stated. air is drawn through some of the upper openings 12. i There is ac cordinglv, a lowering of the pressure in chamber 20 which chamber is in communication with the space 9!). On account of this lowering of pressure, air flows into chainber 20 through opening 21. Furthermore, because under nearly closed throttle conditions, there is a relatively small movement of air through the main air intake 6, the pressure at the throat of the venturi 8 is practically atmospheric pressure and consequently under this condition air also may flow into chamber 20 through the passage 19 from the interior of the venturi. This flow of air into chamber 20 through passage 19 and opening 21 is sufficient to keep the lowering of pressure in chamber 2 0 and consequently in the fuel Well space 96 very small, so that under these operating conditions very little fuel will be caused to flow into the fuel well 9 through passage 10 due to the depression in pressure in 9?). As fuel is drawn out of the fuel well 9 through passages 12 the fuel level in the well 9 will be lowered until sufficient gravity head is established between the fuel level in 9 and in the float chamber 4 to cause fuel to flow into 9 through the calibrated orifice Operation under wide open throttle conditions at low engine speeds Vith the throttle in wide open position, the full suction induced by the engine is thrown directly upon the main intake 6 and upon tube 16. The strong rush of 'air induced through 6 produces a considerable drop of pressure at the throat of the venturi 8. Such drop is communicated through passages 17, 18 and 19 to chamber 20 and thus acts to modify the pressure conditions therein. 'The pressure conditions in this chamber are also controlled by the port opening 21. The ultimate resulting depressed pressure conditions in chamber 20 are communicated to space 96 and there act to cause the drawing into the fuel well 9 of fuel at a rate which is coordinated to the air speed through the venturi.

It will be remembered that under the previously described operating conditions there was practically no depression of pressure in 9/) and accordingly the fuel is supplied to the well 9 at a comparatively more rapid rate through duct 10 when there is a greater depression of the pressure in 91) than when there is practically no depression of pres sure in such space 97). However, it must be remembered that there is a comparativelyrclatively greater depression of pressure in space 30. The effect of this is notwithstanding the relatively greater flow of fuel to well 9. to remove the fuel more rapidly therefrom and to lower the fuel level in space 9 to a relatively loWer point. The ultimate result is that the fuel gravity head is available in addition to the suction .in space 96, to induce the fuel flow through 10 into the well and ultimately secure a relatively rich mixture for running with wide open throttle at ,low engine speeds.

Operating with wide open throttle with high engine speeds With high engine speeds, the foregoing operating conditions and effects are modified in this manner. The fuel gravity head remains. as before because the fuel level in well 9 cannot be lowered any further or beyond the lowermost opening 12. \Vith such gravity head remaining constant, the increase in fuel flow is brought about only by the increase in Venturi suction. The dimensions of the venturi 8 are such that suchventuri acting alone will not produce the required richness of mixture and the suction produced by this venturi must be supplemented by the head of the fuel in constant level of the fuel reservoir 4. At relatively lower air speeds the fuel head from 4 is dominant with respect to the suction head which is available from the venturi but as air speeds increase the suction from the venturi becomes pre-dominant while the'fuel head from 4 remains fixed. The ultimate action is thus to provide a relatively leaning out of the mixture as air speeds increase. To further explain this leaning out action, reference will be made to an illustrative example. For purposes of illustration and explanation only assume that the fuel head in 4 to be 1 inches of water and that the suction produced by the venturi 8 for a certain air speed to be 2 inchesof Water. Accordingly, the result of the total head which is available for the flow of fuel is that of the sum of tWo or 3 inches 'of water. Now assume that the air speed through 8 is doubled, thus producing for example, a Venturi created suction of 4 inches of water. The fuel head from 4 remains constant at 1 inches. The sum of 4 plus 1 inches equals 5% inches which lacks 1% inches of being double in the initial total head Whichwas previously available, i. e. 3.5 times 2 equals 7 which equals 5 plus 1 Thus the 1 inches of water represents relatively the amount of leaning out of the mixture which is obtained as the air speed increases. The ultimate result is a progressive leaning out of the mixture as the engine speed increases with the throttle in wide open position.

It will be understood that the su'tion produced by the venturi in space 97) should not be permitted to reach the suction produced in tube 11. If such an effect took place the fuel-level in 9 would-rise until it discharged fuel into chambcrQO. Such undesired action is prevented by the port 21 which insures Operating with throttle in intermediate po.si

tions and normal running speeds" It will be assumed that valve 3 is open say 20%. Under these conditions the rush of airpast the throttle will be mostly around the edges of the throttle which points are somewhat remote from the end of conduit- 16. Under these conditions also the slot 14 will be so far displaced from the end of the conduit 16 as to have'its effect of inducing air flow through the conduit 16 much reduced. The ultimate result is to induce a relatively less depression of pressure in 16 than would be induced therein with the same air speed through the carburetor and with the throttle valve in wide open position. Under wide open conditions as before explained the full suction of the engine is effective upon the tube 16 and the velocity of the air as it rushes past the tube at its periphery augments this suction. Accordingly the depression in 16 is relatively less with relatively closed throttle positions.

The ultimate pressure in chamber 20 and 9?) depends upon the action of the venturi and the Withdrawal of air from the chamber through ports 12. lVith the relatively less depression of pressure in 16 and 11 relatively less air will be withdrawn through the ports 12 from 96 and 20. tively less effective suction in 9b and accordingly relatively less rapid withdrawal of fuelfrom 4 through 10 into 9. Accordingly the fuel mixture which is produced under these conditions is relatively lean.

If the engine speed varies under the foregoing conditions the venturi will cooperate to vary the amount of fuel which is supplied.

Sun'imarizing it may be mentioned that the present carburetor is of the so-called plain tube type and it is also incorporates a Venturi device disposed in a novel location.

\Vhat I claim is:

1. A carburetor having therein an air intake passage. avcnturi, a mixing chamber.

This will result in relabeing disposed in the air intake at a point ahead of all of the fuel supplying means.

2. A carburetor of the straight tube type and including in combination with fuel supplying tube parts of the carburetor, an air intake, a venturi disposed remote from said fuel supplying tube parts and in the air intake, and means'including passages leading into the venturi and connected with the tube parts for modifying the fuel supplying action of'said tube parts by varying the pressure conditions therein in accordance with the air speed through the main air intake and said venturi.

A carburetor with a mixture outlet and an air intake, a venturi therein, a fuel well subject to the suction of said venturi and connected to the mixture outlet at a point entirely beyond the venturi so as to supply all the fuel mixture at such point, a throttle valve, and means for modifying the suction etfect of the venturi upon the fuel well in accordance with the degree of throttle opening, said mentioned means including a passage for the fuel from the fuel well to the mixture outlet of the carburetor.

4. A carburetor with an air intake, a venturi disposed therein, a fuel well subject to the depression produced by said venturi, a throttle valve, a conduit adjacent said throttle valve and disposed so that the depression produced in said conduit by the suction of the engine is varied by the degree of opening-of the throttle, means for supplying fuel through the conduit which extends adjacent the throttle for all running condiions including wide open throttle conditions, means for communicating said depression in said conduit to the fuel well and for modifying the depression therein induced by the aforesaid venturi.

.3. A carburetor with a fuel well from which fuel is supplied to a mixture outlet, said fuel well being adapted to supply all fuel through said outlet which is required for all the various operating conditions of the carburetor, and means for subjecting said fuel to various offsetting pressure effects, said means including a venturi in the carburetor air intake to provide one pressure effect and a conduit extending adjacent the throttle for providing another pressure effect.

6. A carburetor with a main mixture conduit, and an auxiliary air conduit leading thereinto. and means for supplying fuel to the auxiliary air conduit, a throttle valve in the main mixture conduit and cooperating with said auxiliary air conduit to cause the flow of air through the main mixture conduit by its velocity heads to supplement the depression of pressure induced in the auxiliary ai-r conduitby the suction of the engine.

I. A carburetor provided with a mixture outlet, an air intake, a venturi disposed therein, a throttle valve, a supplemental conduit adjacent said throttle valve, said throttle valve cooperating with the end of said sup plemental conduit so that an increase in the degree of throttle opening will cause the engine suction and the velocity head induced by the rush of air from the air intake past the supplemental conduit to produce an increase in the depression in said supplemental conduit, a fuel well associated with the aforesaid supplemental conduit and in communication with the venturi so as to be subject to the depression induced as aforesaid in said supplemental conduit and induced in the venturi, and means admitting fuel from the fuel well through said conduit to the mixture outlet of the carburetor.

8. A carburetor of the straight tube type with an associated fuel well, an auxiliary air conduit opening at one end directly to the atmosphere and receiving the fuel, and a supplementary means for controlling the fuel supplying action from said well, said means comprising a venturi capable of receiving air only disposed in the air intake conduit of the carburetor and having passages connected to the fuel well to adjust the pressure therein according to the flow of air through the venturi, the aforesaid auxiliary air conduit of the carburetor being disposed at a point beyond the venturi.

9. A carburetor having an air intake, a venturi in said intake adapted to receive air only, a fuel well connected to deliver fuel mixture entirely beyond the venturi and passages connecting the throat of the venturi t0 the fuel well for the purpose described.

10. The invention set forth in claim 9 in which a controlled port is provided from the atmosphere to said passages for modifying the suction induced by the venturi.

11. A carburetor having a mixing chamber, an air intake, a throttle valve, and provided with a fuel well with means for deli vering from the fuel well into the mixing chamher all of the fuel mixture which is required for all operating conditions of the carburetor and including in combination, cooperating suction inducing means which produce an ultimatesuction upon the fuel in the well which is the resultant of several suction effects, such suction inducing means including a venturi in the air intake for inducing one suction effect upon the fuel in the Well in accordance with the air speed through the air intake and into which venturi air only can flow, said suction inducing means also including a conduit extending in proximity to the throttle for inducing another suction effect upon the fuel in the Well in accordance with the degree of throttle opening.

12. A carburetor having therein an air intake passage, a venturi, a mixing chamber which is in unrestricted communication with the open end of the venturi, means for supplying fuel and air to said mixing chamber, a passage connecting the venturi with the aforesaid means to properly proportion the fuel and air which is supplied to the mixing chamber, said venturi being disposed in the air intake at a point ahead of all of the fuel supplying means.-

13. A carburetor having therein an air intake passage, a mixing chamber, a 'venturi having one end opening into communication with said mixing chamber through a main air passage, means ,for supplying fuel and air to the said mixing chamber, and passages supplemental to the main passage connecting the venturi with the mixing chamber Which connect the venturi With the aforesaid last mentioned means to properly proportion the fuel and air which is supplied to the mixing chamber, said venturi being disposed in the air intake at a point ahead of all of the fuel supplying means.

11 testimony whereof I hereto aflix my signature.

EDVVAR-D F. GEIGER.

Images