US 2763285 A
Description (OCR text may contain errors)
United States Patent This invention relates tothe carburetor ofV an internal combustion engine.
In a carburetor of an internal combustion engine, there isa barrel portion providing a conduit through,` which the atomized` fuel and air ilow tothe intake manifold. In this conduit or duct there is athrottle valve to control the passage of the gas therethrough. Along theY barrel portion there is a channel for conducting fuelv and air mixed to the conduit. Openings from this channel through the barrel provide for passage` of the mixture vduring the slow running of the engine, and a solid screw isusually provided to control the passage of the mixture `into the barrel.
One of the objects of this invention is to provide a valve which may be substituted for the usual adjusting screw 'for the slow running control: ofthe carburetor.
Another object of the invention is to provide for admitting air to the slow running fuel supply channel automatically at times when the relative pressure in the intake manifold is low.
Another object of the invention is to provide an arrangement by which greater economy of fuel may be provided.
Another object of the invention is to control rough running of the engine under slow running conditions.
Another object of the invention is to make starting of the engine easier.
Another object of the invention is to assist in overcoming the inertia of the fuel at times of acceleration so that greater acceleration may be had.
With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.
In the accompanying drawings:
Figure 1 is a sectional view of the lower portion of a carburetor as connected to the engine manifold which is in elevation;
Figure 2 is a side elevation of my device on a larger scale than that shown in Figure 1 and separate from installation; and
Figure 3 is a sectional view on line 3-3 of Figure 2.
In proceeding with this invention I have provided a screw which may be substituted for the slow running adjusting screw usually a part of the carburetor. I have provided an axial bore through this screw with an arrangement so that a valve may control the passage of air through the screw, and I have connected this device to the intake manifold so that when the pressure is reduced in the manifold, such as during deceleration of the engine, the air valve may be opened to permit the passage of a greater amount of air into the slow running fuel supply channel, thus increasing the relative proportion of air to fuel in the slow running channel and using less fuel than would otherwise pass into the main conduit.
With reference to the drawings, 10 designates the intake manifold of an internal combustion engine. 11 is the lower barrel portion of a carburetor mounted by means of abutting anges on the manifold and having a, conduit 12 therethrough for the passage of, av mixture of fuel and; air'to the interior 13 of the intake manifold forfsupplying fuel to the different cylinders.` The passage of this fuelmixture is indicated by the arrows. A channel 114 on the barrel portion is connected to the -slow running mixture supply for furnishing fuel mixture through ducts 15 and 16 tothe fuel mixture conduit 512, whileV a boss 17' having a threaded bore 18 therethrough usually receives a solid screw having a conical end for controlling the amount of fuel mixture which may pass through the duct 16. I remove this solid*` screw which is usually present in the threaded opening 18 and substitute;V the devicedesignated generally 20 and shown lay-itselfv in Figure 2. A
This devicecomprises a body. portion 21 which has Va hollow chamber or cylinder as at 22 lengthwisel thereof. t This body is reduced at one end as-at 23 and threaded along its'outer surface as at-24 to thread into the threads 18 of the; boss 17. It i's provided with aconical end '25 and hasl an axial bore 26 along this reduced portion extending from the chamber 22 of the body to the coni- Cal end whereV the bore branches outwardly as at 2'7 and 28 for discharge into the channel 14. An opening 29: is provided in the wall30, of the, body 21 and a valve 31 of a generally cupl shape is slidable in the chamber or cylinderv 22 of the body and: pressed by springl 323 so Vas to close the opening- 29in l this 'wall 30. A plug 33 -is threaded onlitsA outer surfacer 34' to; engage threads 35 on the inner surface of the chamber to be threaded to different positions axially of the body to provide a variable abutment for the spring 32 so that its pressure may be varied as desired. An opening 36 extends through this plug. A nipple 37 also engages these threads and extends beyond the end of the body 21. A flexible tube 38 may be slid over the end of this nipple 37 to be connected to a nipple 39 extending from the-manifold 10.
A throttle valve 40 is mounted on a shaft 41 in the conduit 12 to control the supply of fuel mixture therethrough.
In operation the throttle valve 40 is used for controlling the speed of the engine. When the engine is running at slow speed, the amount of fuel mixture supplied through the slow running ducts 15 and 16 becomes important. Should the throttle be suddenly opened, the pressure in the manifold 10 would be increased relative to atmospheric pressure. Therefore, the valve 31 would be moved to closed position by the spring 32, thus cutting off the supply of air to channel 14, thus assisting to overcome the inertia of the fuel which is moving through the conduit 12 and resulting in greater acceleration. If deceleration suddenly occurs, then the pressure in the manifold 10 will be suddenly reduced and suction on the valve 31 will cause it to open against the action of the spring, permitting air to pass into the channel 14 and with the fuel mixture therein then into the conduit 12, cutting down the relative amount of fuel which will be passed into the manifold and saving fuel by breaking down the fuel mixture to decrease the relative amount of fuel in the mixture.
This automatic control also serves to control the roughness of the engine under slow running conditions by this automatic admission of air during slow running conditions or quick deceleration. The amount of opening of the valve 31 will depend upon the differential pressure, thus making the supply of air proportional to the differential pressure or slow running conditions which are encountered.
This valve also operates economically to save fuel the same in descending a hill because of the less relative pressure which opens the air valve and causes a greater proportion of air to be drawn in. The over-running causes much less relative pressure than-under ordinary slow running condition, and thus a greater fuel saving than would occur under normal slow running conditions.
It will be noted that the slot 29 is of a narrow, elongated characterY and that the spring 32 is relatively long and flexible and thus one which permits an extended movement of the cup 31. In the slow running of an engine the variation in vacuum pressure is slight, and therefore the long movement of the cup and elongated slot permit regulation during this slow running of the engine where the vacuum variation is small, and thus a balanced differential of air and fuel mixture under slow running conditions may be provided.
1. In a fuel supply system for an internal combustion engine having an intake manifold where the pressure may be less than atmospheric pressure, a carburetor having a conduit to said manifold, a slow running fuel supply channel having a xed open passage to said conduit with a valve seat at the supply channel end thereof, a boss on a wall of the channel with a threaded opening therethrough in axial alignment with said passage, that improvement which comprises a device installed in said threaded opening and provided at one end with an integral valve to be moved by rotation of said device toward and from said valve seat, said device having an axially extending air conduit therethrough connecting said supply channel with atmospheric pressure, a valve movably mounted in said device controlling said air conduit,
a spring in said device urging the valve to close the air conduit, and a tube directly connected to the intake manil fold and subjecting the valve to the reduced pressure of said manifold to operate the valve against the action of said spring to open the air conduit upon a pressure differential to permit air to enter the slow running fuel supply channel.
2. In a fuel supply system as in claim 1 wherein the air conduit in said device is a bore extending axially therethrough and is provided with an elongated laterally extending slot opening to the atmosphere, and said valve is movably mounted in said bore and is slidable to close said slot.
3. In a system as in claim l wherein the air conduit comprises a tube with an elongated slot therein and said valve is in the tube and closes said slot and uncovers said slot gradually as the valve moves along said tube toward open position, said slot being open when the engine is slow running.
References Cited in the tile of this patent UNITED STATES PATENTS 1,102,303 Sly July 7, 1914 1,477,989 Amori Dec. 18, 1923 1,678,459 Bowland July 24, 1928 2,036,205 Ericson Apr. 7, 1936 2,112,602 Loebs Mar. 29, 1938 2,152,028 Church Mar. 28, 1939 2,453,125 Flint Nov. 9, 1948 2,506,511 Mallory May 2, 1950 2,621,911 Lindsteadt Dec. 16, 1952 2,626,790 Betcher Ian. 27, 1953 FOREIGN PATENTS v 405,346 Great Britain Feb. 8, 1934