US1872555A - Carburetor - Google Patents

Description

F. 0. BALL ET AL CARBURETOR Filed April 18, 1930 Aug.'v16, 1932.

INVENTOR FEEDER/CK 0. BALL THOMAS M. BALL.

6 E ATTORNEY Patented Aug. 1 6, 1932 UNlTED STATES PATENT OFFICE FREDERICK 0. BALL AND THOMAS M. BALL, OF DETROIT, MICHIGAN CARIBURETOR Application filed April 18, 1930. Serial No. 445,502.

This invention relates tofuel level regulating apparatus for carburetors.

Heretofore, in carburetors of the type used -'in internal combustion engines, the level of the fuel in the reservoir wlth which the fuel nozzle communicates has been maintained at a substantially constant elevation considerably below the outlet orifice of the nozzle so as to prevent the fuel from spilling out of the nozzle and to obviate uneven feeding of fuel to the mixin chamber of the carburetor. A fuel level in the nozzle which is low with respect to the discharge orifice thereof is advantageous during all conditions of operation when the vacuum in the manifold is relatively high. Such a level, however, is a material detriment when the manifold vacuum is low, as for example, at low speed, wide open throttle operating conditions, for under these conditions the vacuum is insufficient to both lift the fuel to the orifice of the nozzle and feed it properly so as to maintain a normal mixture ratio. As a result, low speed, wide open throttle engine operation is faulty when the fuel level in the nozzle is low with respect to the orifice thereof and operation at a high-manifold vacuum is faulty when the fuel level is high.

The main objects of this invention are to 99 provide an improved carburetor in which the level of the fuel in the nozzle is automatically controlled so as to retain fuel in closer proximity to thedischarge orifice of the nozzle at stages of; felatively lower manifold vacuum than at stages of higher manifold vacuum; to provide means of this kind which will produce rapid changes in the elevation of the 'fuel in a fuel reservoir and communieating nozzle of a carburetor; and to provide a device of this kind which is susceptible of I operation by manipulation of the throttle of the carburetor.

' An illustrative embodiment of our invention is shown in the accompanying drawing, 15 in which: i

Fig. 1 is a side elevation of an internal combustion engine embodying our invention.

Fig. 2 is a vertical central section'of a carburetor having an improved fuel level reg-.

ulating apparatus.

Fig. 3 isa fragmentary elevation, partly in section, of a carburetor embodying a modified form of our invention.

In the form shown, the invention is illustrated in connection with an internal combustion engine 1 of the type used in motor vehicles, having an intake manifold 2 on which a carburetor 3 is mounted. The carburetor 3 includes a cast metal body part having upper and lower sections 4 and 5 in which communicating passages 6 and 6 respectively are provided. The passage in the lowersection 5 has an air inlet 7 in which a choke valve 8 ismounted and the passage 6 in the upper section 4 has a fuel mixture outlet 9 in which a 66 throttle valve 10 is mounted on a shaft 11, the mixture outlet 9 being in communication with the intake manifold 2. These passages together form a mixing chamber in which mixtures of fuel and air are formed of suitable 10 proportions for proper combustion in the cylinders of the engine. 7

A fuel reservoir 12 is located in-the lower section 5 of the body part of the. carburetor and is substantially covered by a wall 13 on 76 the upper section 4. An inlet 14 formed in the wall 13 and communicating with the interior of the reservoir 12 admits fuel thereinto. The inlet 14 is connected with a fuel supply system, not shown, and it has a valve seat 15 and a valve guide 16 in which a vertically shiftable valve 17 having a valve stem 17 is mounted.

Pivoted ona bracket 18 on the upper section of the carburetor is a lever 19 which has 5 a float 20 on its outer end located in the fuel reservoir 12, The lower end of the valve stem 17 normally rests upon the lever 19 which holds the valve 17 in a closed position when the fuel level in the reservoir is at a predetermined elevation.

A cylinder 21 is provided on the upper section 4 of the body part of the carburetor having its lower end in communication with the interior of the reservoir 12 and located directly above the float 20, and its other end communicating through a passage 22 with the mixture outlet 9betweenthe throttle 11 and the manifold 2. Slidably mounted in the cylinder 21 is a plunger 23 which has a piston 23 closely fitting the inner walls of the cylinder. The plunger 23 is held in the upper full line position, shown in Fig. 2, out of engagement with the float 20 by the manifold suction when the manifold vacuum is relatively high.

A fuel nozzle 24 is mounted on the bottom wall of the lower section 5 of the carburetor and is connected by a passage 25 with the interior of the reservoir 12. The nozzle 24 is of the air bled type and is surrounded by a casing 2% having an annulus or well 26 which communicates with the atmosphere through a passage 25. Communicating with the lower end ofthe aunulus 26 is a by-pass passage 27 which opens at 27 into the mixture outlet 9 of the carburetor. The fuel flows from the reservoirinto the nozzle and seeks a level of the same elevation therein as the level of the fuel in the reservoir. Thus the float 20 retains the fuel in the nozzle and in the reservoir at substantially the same elevation.

In the form shown in Fig. 3, the carburetor has a mixing chamber having a fuel mixture outlet 9, in which a throttle 10 is mounted on a shaft 11. A. fuel reservoir 12- is provided in the lower section 5 of the carburetor having an inlet 14 through which fuel is fed to the interior of the reservoir. Formed in the inlet is a valve seat 15 upon which a valve 17 is seated. The valve 17 is normally held in a closed position when the fuel level in the reservoir is at a predetermined elevation by a float 20' which is pivotally mounted on a bracket 18 on the upper section 4' of the carburetor by a lever 19'.

Slidably mounted in a tubular guide 28 formed on the upper section 4' is a plunger 29 having a head 30 at its outer end. The inner end of the plunger registers with the float 20. The plunger 29 is normally held In its upper position shown in Fig. 3 by a lever 31 which is pivotally mounted on a bracket 32 on the wall of the mixing chamber. The right end of the lever 31 engages the lower side of the head 30 and the left end of the lever 31 engages a cam member 33 on a lever 34 which is rigidly clamped on the shaft 11 of the throttle 10 by a screw 35.

When the throttle is in a substantially closed position the cam 33 tilts the left end of the lever 31 downwardly thereby holding the plunger 29 in an elevated position, and as the throttle 10' is rotated to a substantially open position by the lever 34, the cam 33 is rotated in a clockwise direction permitting the plunger 29 to move downwardly and bear upon the float 20 under its own weight. This action of the plunger 29 decreases the buoyancy of the float 20 and in so doing raises the level of the fuel in the reservoir 12. r

In operation, when the throttle 10 of the carburetor shown in Fig. 2 is closed to any position which causes a relatively high vacuum in the manifold during operation of the engine, it is necessary to retain the fuel level in the nozzle substantially below the outlet orifice 36 thereof to secure proper functioning and satisfactory mixture ratios.

lVith the plunger 23 in the elevated posit'on shown in full lines in Fig. 2, the float 20 maintains a fuel level substantially at the elevation indicated by dotted line 37. When the manifold vacuum is decreased by rotation of the throttle 10 to a substantially open position the plunger 23 falls and rests upon the float 20. This action causes the float to be immersed to a further degree in the fuel of the reservoir 12 and substantially instantaneously raises the level of the fuel in both the reservoir and nozzle to the elevation indicated by the dotted line 38 where the fuel is slightly below or slightly above the outlet orifice 36 of the nozzle. The level of the fuel remains at its higher elevation until the manifold vacuum is again built up by rotation of the throttle 10 to a relatively closed position;

lVith the above fuel level regulating apparatus, the level of the fuel in the nozzle is retained at a substantital distance below the outlet orifice thereof when the manifold vacuum is relatively high. When the vacuum in the manifold is relatively low the level of the fuel in the nozzle is raised so as to cause substantially instantaneous feeding of fuel through the outlet orifice 36 thereby providing the necessary fuel supply to enrich the quantity of air supplied to the intake manifold. In this manner, a fuel mixture of sufliciently high fuel richness is supplied to the engine during the low speed, open throttle stage of operation.

The provision of a low fuel level in the nozzle at conditions of relatively high manifold vacuum causes feeding of fuel from the nozzle to be delayed or held back until the air passage through the carburetor is at a relatively high velocity, thereby preventing an excessive increase in the mixture ratio when the idling by-pass ceases to be the dominant fuel feeding factor at the beginning of the nozzle feeding stage.

In the form of our invention shown in Fig. 3, the same operating cycle occurs under mechanical control of the throttle actuating lever and cam 34 and 33 respectively.

Although but two specific embodiments of this invention have herein been shown and described, .it will be understood that various changes including the size, shape and ar rangement of parts may be made without departing from the spirit of our invention and it is not our intention to limit its scope other than by the terms of the appended claims.

We claim 1, In a Carburetor having a throttle, a fuel reservoir having an inlet, a nozzle communieating with said reservoir, a valve in said reservoir, valve actuating means including a float for maintaining a predetermined fuel head in said reservoir and on said nozzle when said throttle is substantially closed during operation of said carburetor, a member shiftably mounted on said carburetor and engageable with said float for substantially submerging said float in the fuel of said reservoir so as to rapidly raise the. fuel level therein and increase the fuel head on said nozzle by displacement of fuel at substantially open throttle operation of said carburetor, and means for holding said member in spaced relation to said float when said throttle is closed, said means being adapted to release said member when said throttle is opened.

2; A carburetor having a mixing chamber therein, a throttle at one end of said mixing chamber, a fuel reservoir in said carburetor having an inlet, a cylinder communicating at one end with said reservoir and at its other end with said mixingchamber on the suction side of said throttle, valve mechanism including a float for predetermining the fuel level of said reservoir, and a plunger slidably mounted in said cylinder and engageable with said float for raising said fuel level, said plunger being normally held out of engagement with said float by the vacuum in said mixing chamber when said vacuum is high.

3. In an internal combustion engine having an intake manifold, a carburetor communicating with said manifold and having a fuel reservoir, a valvein said reservoir for controlling the feeding of fuel thereto, valve actuating mechanism including a float for predetermining the fuel level in said reservoir, a cylinder communicating with said intake manifold and said reservoir, a piston in said cylinder in registration with said float normady held from contacting therewith when the manifold vacuum is high and adapt ed to bear down upon said float when the manifold vacuum is low for raising the level of the fuel in said reservoir.

4. In an internal combustion engine having an intake manifold, a carburetor communicating with said. manifold and having a fuel reservoir, a fuel nozzle in said carburetor, a valve in said reservoir for controlling the feeding of fuel thereto, valve actuating mechanism including means for predetermining the fuel level in said reservoir and the head of fuel on said nozzle, a cylinder communicating with said intake manifold and said reservoir, a piston in said cylinder engageable with said mechanism and adapted to bear down thereon when the manifold vacuum is low for raising the level of the fuel in said reservoir to increase the head of fuel on said nozzle, said piston being normally held from engaging said mechanism by the suction in said cylinder when the manifold suction is high.

5. A carburetor including a throttle valve, a fuel reservoir having a fuel inlet, afuel valvein said inlet, mechanism for controlhng said fuclwalve including means for maintaining a predetermined fuel level in said reservoir, a member movably mounted on said carburetor engageable with said mechanism for raising said fuel level, and means normally holding said member out of engagement with said mechanism when said throttle is closed during operation of said carburetor and adapted to release said member when said throttle is opened toa predetermined position.

6. A carburetor having a fuel mixture passage, 'a throttle valve in said passage, apparatus for controlling said throttle, a fuel reservoir having a fuel inlet, a fuel valve in said inlet, mechanism for controlling said fuel valve including means for maintaining a predetermined fuel level in said reservoir, a member movably mounted on said carburetor and engageable withsai-d fuel valve controlling mechanism for raising said fuel level, and means operable by said throttle control apparatus normally holding said member out of engagement with said fuel valve controlling mechanism when said throttle is closed and adapted to release said memher when said throttle is opened to a predetermined position.

7. A carburetor having a fuel mixture passage, a throttle valve in said passage, a fuel reservoir having a fuel inlet, a fuel valve-in said inlet, mechanism for controlling said fuel valve including means for maintaining a predetermined fuel level in said reservoir, :1 cylinder communicating with said fuel mixture passage between said throttle and the outlet end of said passage, and a plunger slidably mounted in said cylinder engageable with said mechanism for raising the fuel level in said reservoir, said plunger being normally held out of engagement with said mechanism when said throttle is closed by the suction in said passage.

8. A carburetor including a fuel mixture passage, a throttle valve in said passage, a fuel reservoir having an inlet, a fuel nozzle in said passage communicating with said reservoir, a fuel valve in the inlet of said reservior, mechanism for controiling said fuel valveincluding means for maintaining a predetermined fuel level in said reservoir and apredetermined head of fuel on said nozzle, a 1 member movablymounted on said carburetor engageable with said mechanism for raising the fuel level in said reservoir and increasing the head of fuel on said nozzle, and means normally holding said member out of engagement with said mechanism when said throttle is closed during operation of said engine and adapted to release said member when said throttle is opened to a predetermined position.

9. In a'carburetor having a. throttle, a fuel reservoir having an inlet, a nozzle communicating with said reservoir, a valve in said reservoir, valve actuating means including a float for maintaining a predetermined fixed head in said reservoir and on said nozzle when said throttle is substantially closed dur ing operation of said carburetor, a member for lowering said float when said throttle is substantially open so as to increase the fuel head on said nozzle, and means normally holding said member from engaging said float when said throttle is closed.

FREDERICK 0. BALL, THOMAS W. BALL.

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