US1842475A - Carburetor - Google Patents

Description

Jan. 26, 1932.

Filed Aug 2 Sheets-Sheet l I i: 4o 3 i P52 ..39 5 I X\ 13 6 i l l 9' 6 ll fffi- 7 5h11' '::::::i/ 1 l l i l l l 2s g kas 2023 I l 3o FRED A. KOMMER INVENTOR ATTORNEY Jan. 26, .1932. F A KOVIMER 1,842,475I

GARBURETOR Filed Aug. 9, 1929 2 Sheets-Sheet 2 FRED A. KOMMER INVENTQR ATTORNEY .a to be concentrated on the i'uel jets.

Patented Jan. 26, 193

w: n. una, or sr. hours,

anni, assren'on ro marron, or sfr. nrs, Massenet, a eonrorron or a s i.

TER UBUTR COF'- UBURETR application led linguist t, W29. Serial No. 384,572..

'llhis invention relates to improvements in carburetors,.and particularly to the provision of means in a carburetor for producing a rich mixture suitable for starting and warminge up purposes.

llt is very desirable in the use ot automotive engines to provide a carburetor having alr How passages ot fixed area for normal op eration, tor the provision of an open valve la operated by suction necessarily causes a drag le in extreme low speed operation., for the air tends to pass through the carburetorw without `lifting any tuel at all., it the rate of How is low enough.

lt 'is customary in plain tube carburetors 2o to provide a How restricting valve to be-located near the air inlet to cause the suction This valve is usually manually operated and used only for starting. its soon as the engine starts to run under its own power, the valve must be slightly open to permit the engine to warm up properly. @wing to the considerable change in speed from the starting speed to running speed, or, in other words, the change from the speed at whichthe engine is operated by the starter and that at which it is operated under its own power, considerable difficulty is eX- perienced in adjusting the valve in such a manner that a sufficient flow restriction will be presented at cranking speed without overand warming up, the throttle valve must be adjusted to a slightly open position when the choke valve is closed, and this involves 'delicate adjustments and expensive connections between the choke and throttle.

llt is an object of this invention to provide a carburetor of the plain tube type as far as normal operation is concerned, having a single manually operated choke valve to be used in starting and having means to automatical- 0 ly adjust the amount of air which is permitted to enter without the necessity of manually changing the position of the choke valve.

lt is a further-object of this invention to produce a carburetor having a choke valve for restricting the admissionof air for starting purposes and having means independent of the choke valve for permitting entrance ot additional air as soon as the engine begins to run under its own power.

llt is a further object of this invention to produce a carburetor having means tor adyustmentf to produce a suitable mixture for starting and also having means to permit the warming up of the engine after it starts to run under its own power, the warming up means being independent of the position of the throttle valve. f

llt is a further object of this invention to produce a carburetor having a 'choke valve and having means operated by said choke valve and independent of the throttle valve for producing. a starting and warming-up mlxture.

llt is a further object of this invention to produce a carburetor in which the necessity ot connecting the throttle and choke will be obviated.

@ther objects of the invention will appear from the following specification and the accompanying drawings, referring to which:

Figure l is a sectional elevation of a carburetor having my invention applied thereto.I

Figure 2 is an elevation of the opposite side ofthe carburetor showing Figure l, with parts broken away for clearer illustration of others.

Figure 3l is an end view of the carburetor shown in Figures l and 2, with parts broken away for better illustration of others.

Figure 4 is a plan view ot the carburetor shown in Figures 1, 2, and 3.

The reference numeral 1 indicates a casting forming the main body of the carburetor.

ternal combustion engine. The `body/memf ber l is formed with a seat 5 having a bore 6 from the air chamber 8 and receiving a mixture of fuel and air from a standpipe forming a primary mixing chamber 14. At the side of the air chamber, opposite the main f inlet 9, an opening 16 leading from the air chamber to the atmosphere is formed. This opening is controlled by a suction operated valve 17v seating on an annular surface 18 in they main body member. The valve is carried on a stem 19 which is slidably carried by the supporting member 20. A coiled spring 21 is provided forv seating the valve and this is retained by suitable means, such as a wash er, which is held in place by a cotter pin 22 0r other suitable ,means The supporting member is provided with flanges 23 and is retained in position by screws 24. These screws also serve to hold a suitable shield 25 to prevent the entrance of large particles of foreign matter to the carburetor.

The standpipe 15 is provided with a flange 26 which is threaded into a depression or well 27 in the lower part of the air chamber. The standpipe 15 comprises the mixing chamber 14 which, in the present instance, is formed as a cylindrical passageway, and the primary venturi 28 at the lower end of the primary mixing chamber, and one or more air ports 29 to permit air to enter from the air chamber at the lower end of the venturi 28. A small bleed port 30 permits the passage of air from the air chamber through the flange 26 to the accelerating well 31.

The fuel for the main supply under normal operating conditions is supplied from the float bowl 32 which is attached to the carburetor by a nut 33. The fuel is supplied to this chamber by any suitable means (not shown) and maintained at a suitable level by the usual float and float valve construction. This is very well known in the art and is not shown. The fuel enters the Vport 35 from the float chamber, the bore 34 being plugged, as shown. A main nozzle 36 is threaded into the body member and arranged to receive fuel from the port 35, as shown.

The fuel from the port 35 enters the accelerating well which surrounds the main nozzle and also flows to the chamber 37 which supplies the idling tube 38. This idling tube delivers fuel to a bore 39 in the member 2. An adjusting screw 40 having an air admission port 41 controls the admission of `air to v the upper part of the bore-39, and the`mixture is discharged at the port 42 in the passagemeagre way 10 adjacent the edge of the throttle 11 when it is in closed position.

A choke valve 43 is attached to a shaft 44 which is pivoted in suitable bearings in the air inlet passageway 9. This shaft is manually operable by any suitable means, such as the crank 45, which may be attached to a Bowden wire, or other device, so that it may be operated from the dash of the car. By opening and closing the valve 43, the admission of air through the main air inlet to the air chamber can be governed.

A passageway 46 is formed in the main body member in such a manner as to communicate with the fuel in the bowl 32 and with a transverselyv extending passageway 47 which, in turn, communicates through a second upwardly extending passageway 48 with a second transverse passage 49. From the end of the passage 49 a third upwardly extending passage 50 extends to the seat 5 where it is considerably enlarged as at 51. The body member 2 is provided with an angular upwardly extending passage 52 having an enlarged portion 53 at its lower end to communicate with the opening 51. The pasl sageway 52 terminates in an outlet port 54 above the throttle 11.

The shaft 44 of the choke valve 43 is provided with a transverse passageway 55 registering with the bore 49, as shown in Figure A2. This passageway 55 comprises a valve for turning on oro the flow of fluid from the fuel bowl to the suction chamber in the passageway 10 above the throttle. Suitable plugs 56, 57, and 58 being provided to close the ends of the passageways 48, 49, and 47 respectively. A direct communication between the suction chamber and the float chamber is established by closing the choke valve 43 so that raw fuel will be drawn into the suction chamber. It will be understood that there may be some leakage of air into this passageway, especially around the shaft 44, without seriously interfering with the conveyance of the fuel to the suction chamber.

i It will be understood that when the choke valve 43 is openthe valve 55 will be closed, and vice Versa.

' The operation of the device is as follows:

The carburetor being attached to the intake manifold of an internal combustion engine, and it being desired to start the engine, the valve 43 is closed, thereby opening the Valve 55. The throttle of the engine is en-V tirely closed, except for such leakage as may occur around the port 42, or which may occur through auch clearances as may be present in the normal idling position of the throttle. Thus, there is a double closure against the admission of air to the suction chamber when the engine is rotated by the starter, the throttle valve providing one closure, and the valves 43 and 17' providing another. Atmospheric pressure exists above 1 'lll the level of the fuel in the float'chamber, a

vent 59 being provided for that purpose.v

When the engine is operated by the cranking means, the suction produced in the suction chamber will thus draw raw fuel through the passageway 46-52 from the fuel bowl to the suction chamber. This raw fuel will mix with such air as enters by leakage and form a suitable mixture for starting the engine at low temperatures.

As soon as the engine starts to run under its own power, the requirements for air are increased and the leakage around the throttle Valve, particularly at the port 42, from the air chamber, produce a reduced pressure in the air chamber which opens valve'17 ,permitting the entrance of additional air to the carburetor. This air leaks around the throttle valve into the suction chamber along with air entering the ports 4l and thus forms a mixture suitable for operating the engine at a speed suitable for warming up. When the engine has become sufficiently warm, the choke valve 43 is opened, thereby closing the valve 55 and preventing the How of any more fuel to the tube 4654 in the suction chamber after which the carburetor continues to operate in the usual manner by drawing fuel from the main nozzle 36 and/or the idling port 42, ac-

cording to the speeds and loads at which the engine is operating.

l claim:

l. lna plain tube carburetor, means forming a mixing conduit, a throttle valve and a choke valve in said conduit, means operable by closing said choke valve to conduct raw fuel to saidL conduit at the suction side of said throttle., and a relief valve mounted in a wall of said conduit and adapted to open bv suction to permit air to flow into said conduit between said throttleand said choke, said relief valve being held in closed position at all times, except when said choke valve is closed.

2. ln a carburetor, means forming a mixing conduit,.said conduit being adapted for attachment to the intake manifold of an internal combustion engine, a throttle valve adjacent the outlet end of said conduit, and a choke valve adjacent the inlet end, a fuel chamber, a passageway leading from said fuel chamber to a point in said conduit between the throttle and the outlet, a valve in said passageway, a connection for simultaneously operating said last named valve and said choke valve, and a relief valve between the choke and the throttle for admitting Iair only when said choke valve is closed.

3. lln a carburetor, a throttle valve, a choke valve, means operated by said choke valve for supplying raw fuel to said carburetor at the suction side of the throttle valve, and a relief valve operated by suction to permit the entrance of air into said carburetor, said relief valve being held in closed position at all times, except when said choke valve is closed. f

In a carburetor, means forming an a1r,

4. chamber, means forming an outlet for said air chamber, comprising a mixingI conduit, a Vnormally open main airinlet of sufficient size to supply all the air necessary to operate said carburetor at maximum capacity, and a normally closed auxiliary inlet for said air chamber, means for supplying fuel to said passageway at a point outside of the throttle, a valve for controlling said main air inlet, and means connected to said valve to central said fuel supply conduit.

5. ln a carburetor, a main air inlet of sufficient capacity to supply all the air necessary to operate-said carburetor at maximum capacity, an auxiliary air inlet,'a mixture outlet, a throttle controlling the passage of mixture through said outlet, a fuel bowl, means comprising valves for controlling said air inlets, a connection from said fuel bowl to the mixture outlet, and means operated by one of-said valves for controlling said connection.

ln testimony whereof, ll aix my signature this 2ndvday of July, 1929..

FRED A. KMMER.

' ico

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