US1968870A - Carburetor - Google Patents

Description

' E. v. BEALS Aug. 7, 1934.

CARBURETOR Patented Aug. 7, I934 1,968,870 CARBUBETOR Erl V. Beals, Boston, Mass.

Application September 17, 1928, Serial No. 306,444 Renewed November 30, 1932 Claims. (Cl. 261-50) The main object of this invention is to provide a construction which, when adjusted'prop- V erly to suit the particular engine to which it is applied, will function automatically to supply 5 the engine with a minimum of fuel required for the efficient operation of the engine. The invention also has other objects in view which will appear in the course of the specification.

In the drawing annexed- Fig. 1 is a vertical sectional view of my device;

Fig. 2 is a plan view thereof Fig. 3 is a diagram of one form of electric wiring system for the heater.

Referring to the drawing annexed by refera cam which is provided with a cylindrical surface 13 and an adjoining tangential surface it Bearing upon the face of this cam is a set-screw 15 carried on the end of an arm 16, which arm is afiixed to a shaft 17, which shaft in turn carries an arm 18 whose forked end 19 engages between a pair of flanges 2(l-2l aflixed to a plunger 22, these flanges 20-21 being spaced apart sufficiently to permit a certain amount of play of the fork l9 therebetween. The fork 19 is normally held down on the flange 21 by means of a coil-spring 23 which surrounds an upstanding pin 24 and normally bears down on the top side of said am 18. When in idling position (as shown in Fig.1), the nose of the screw 15 rests on the oblique part 14 of the cam and the fork 19 normally presses down the lower lip 21, and, when the cam is rotated in the direction of the arrow to thus open the throttle, the screw 15 rides up on the circular surface 13 of the cam and thus raises the arm 18, against the action of spring 23, ,to a point between the two flanges 20-21, thus permitting the plunger 22 to have a free play to a limited extent.

To manually raise the arm 18 without opening the throttle 10, I provide an additional shaft 25 which is operable through the medium of a radial arm 26 and which is provided with a cam 2'! located 'under the arm 18, whereby, by rocking shaft 25, the arm 18 may be raised high enough to engage the upper flange 20 and thus raise the plunger 22, for the purpose hereinafter set forth.

The plunger 22 works vertically in a tube 28, and the lower headed .end of the plunger is normally forced downwardly by means of a coilspring 29 housed within the tube 28. This tube 28 screws up and down in a tube 30 and is locked in this position by a nut 31. The tube 30 is in turn screwed into a hole in the top of a disk 32 and is in turn locked by a nut 33. The disk 32 is screwed down into an internallythreaded opening in the top wall of the mixingchamber and is locked in its adjusted position by a nut 34. Thisdisk is hollowed out to form a chamber for a diaphragm 35 which extends entirely across the circular chamber and is clamped in position therein, at the edges of the diaphragm, by meansof a disk 36 screwed up into the ring 32. The disk 32 is provided with holes 3'7 to expose the upper side of the diaphragm to atmospheric pressure at all times, while the disk 36 is provided with holes 22 to expose the lower side of the diaphra to suction pressures in the mining-either.

A disk 39 is located within the diaphragm w chamber, beneath the diaphra, and is normally pressed up against the diaphragm by means of a coil-spring til housed in a central boss formed on the disk 36, this boss being eirtended downwardly in the form of a tube ti to 25 form a guide for a needle-valve 42, the upper end of which is attached to the aforesaid disk 39. The lower pointed end of the needle-valve cooperates with a conical valve-seat formed in a disk 43 which is screwed down into a cavity W in the bottom of the carburetor-casing, just below the usual venturi 42.

To form a heating-chamber for the fuel, the bottom of the mixing-chamber is extended downwardly in the form of a tube 45 which depends through a hole formed in the bottom of the float-chamber 46, the lower end of this tube-45 being externally threaded for the reception of a clamp-nut 47 which clamps the bottom wall of the float-chamber against a flange 48' formed on the depending tube 45.

The disk43 is provided with an annular groove 49, and from this groove extends inwardly a series of passages 50 which deliver air into a central cup 51 formed in the disk t3 around the fuel-opening. Air is supplied to the groove 49 and passages 50 through a passage 52 formed in the lower wall of the carburetor-casing and having its inlet communicating with the intake of the carburetor at a Point outside of the 119 throttle. An adjustable screw 53 governs the amount of air which is permitted to pass down through the passage 52 to the passages 49 and 50.

Within the tube 45 is fitted an insulating tube 54, the upper end of this tube being provided with an annular shoulder 55 which rests on an upwardly-facing shoulder formed in the inner wall of the tube 45, below the disk 43. The disk 43 is screwed down onto the top end of the insulating-tube 54, a sealing-gasket being interposed between these two parts to prevent upward escape of the fuel except through the valve-controlled inlet. The tubes 45 and 54 are provided with alined openings 56 to permit liquid fuel to flow from the float-chamber into the interior of the insulating-tube 54.

Within the tube 54 is mounted an electrical heating-unit consisting of an upstanding rod 57 insulatedly supported within .a plug 58 screwed into the lowerrend otthe insulatingtube 54. A nicrome heating-wire 59 is electrically connected to the plug 58 at one end and to the upper end of the rod 5'7 at the other end. To the upstanding end of the rod 57 is connected, in any suitable manner, an electrical conductor 60, and to the plug 58 is connected the other terminal 61 of an electrical circuit,

so that, when current is supplied to the circuit 60-61, the wire 59 will be heated, thus heating the fuel in the chamber formed by theinsulating-tube 54. An insulating washer 62 is arranged between the headed fiange of the plug 58 and the nut 4'7, the lower end of tube 45 and the lower end of tube 54, a suitable sealinggasket being employed to insure against leakage of the liquid fuel. Another insulating washer 63 is desirably employed between the clampnuts 64 and the bottom end of the plug 58. The insulating tube 54 is desirably locked in position by means of a set-screw 65.

The electrical heating-device herein shown and described is substantially the same as the one disclosed in my co-pending application Serial No. 216,264, filed August 29, 1927, which has since matured into Patent No. 1,739,818 dated Dec. 17, 1929. In the present construction, however, I make the tube 54 of heat-insulating material to thus do away with the dead-air space shown in my pending application and to more effectively conserve the heat generated by the electric wire. In this construction, I also form the valve-seat in a separate metal disk fitted into the bottom of the mixing-chamber rather than in the integral top of the inner tube. In this construction, I also screw the closure-plug 58 directly into the insulating tube 54 rather than connect the same' to the lower end of said tube by means of an insulating tube, as in the pending case. The present construction is more eflicient in conserving heat and is more easily manufactured, and, besides, more effectually seals the liquid fuel against escape either downwardly out of the float-chamber or upwardly into the mixing-chamber. In the pending case, I show a series circuit arrangement for controlling the supply of current to the heating-wire, whereas in the present case (in Fig. 3) I show a parallel system of connection. In the present system, the plug 58 is grounded in the carburetor-casing, and I connect the conductor 60 from the generator G to the terminal .57, the battery conductor 67 being connected to this same terminal and provided with a dash-switch S for priming with the battery 68, the other terminal of the battery being grounded. The conductor 6'7 is connected to the generator through a relay cutout R. The other terminal of the generator is connected to ground through a manually-controlled rheostat 69. The relay cutout R (which exists in all battery-charging systems) works to prevent the battery from acting on the heating-unit when the engine is idle and the switch S is open. The dash-switch S, manually controlled, is a plain two-pole switch instead of the grounding switch illustrated in the pending application.

I have shown my metering devices in association with my improved electrical heater arrangement, but it will be understood that my metering arrangement may be used with any other type of carburetor without departing from the scope of my patent.

In Fig. 1, the parts are shown in idling position, in which position the throttle 10 is closed, the adjusting screw 15 resting on the cam-face 14, and the two springs 23 and 29 are combining their strength to force the diaphragm-disk 39 down against the stop-disk 36, thus holding the needle positively in idling position. ,This idling position of the needle is determined by screwing the ring 32 (which carries the entire metering unit) up or down in the wall of the carburetor, the ring being locked in nicely adjusted position by means of the nut 34. The idling air is mostly taken in through the duct 52 which is controlled as heretofore stated, by the adjusting-screw 53. This supply of air is delivered through the radial ducts 50 into the cup 51, close to the point of emission of the fuel, so as to thereby insure a thorough intermingling of the gas and air.

When the engine is to be primed, the shaft 25 is rocked to raise the arm- 18 up against the flange 20, to thus release the diaphragm of the pressure of the two springs 23 and 29, thereby allowing the spring 40 to automatically raise the diaphragm and with it the needle, thereby insuring a rich mixture for starting the engine.

The diaphragm is placed between two opposing springs (the top one adjustable), so as to be able to accommodate or attune its action to the diiferent engines which exert varying suction pressures. The tension of spring 40 is greater than 29, so that the diaphragm and needle would remain in the uppermost position when the engine is stopped and the intake suction ceases, if it were not held down positively by the idling mechanism already described.

When the engine is running, this idling restraint is automatically cut out by action of the cam 13, as already stated, leaving the diaphragm, as adjusted, free to move up or down according to the absolute pressures of the manifold. In fact, the diaphragm and needle float upon the intake vacuum. Since the butterfly is in the position of a choke, the, suction decreases as it is opened, and, vice versa, increases as the butterfiy is closed. Dynamometer tests show that, with the throttle wide open, the vacuum is as low as two inches of mercury; and, with the butterfly closed (as during the idling period) as high as seventeen inches of mercury. From these facts, it will readily be seen that the absolute pressures are utilized in this invention as a measure of the amount of air passing, and that the diaphragm, controlled by such pressures, automatically positions the needle settings in accordance therewith to. maintain the air-fuel ratio. Now, since there is no buretors.

damper of any sort between the manifold and the fuel-orifice, the suction of the engine has a direct pull on the fuel, which pull is intensified as the throttleis being closed, so that the fuelorifice is much more minute than in jet car- For instance, the orifice for idling purposes is but little more than that of a fith inch drill. This extreme smallness of the orifice acts beneficially in breaking up the fuel more finely due to its extra high velocity. This fact, coupled with the extra volatility given to the fuel by the electric heat unit, is the means of obtaining a homogeneity of mixture far in excess of any jet or wet mixture device. This diaphragm-controlled needle is in fact equivalent to an infinite number of jets brought into play successively and automatically in accordance with engine requirements.

The engine is started with the butterfly closed. This puts the whole suction of the engine on the fuel, the same as closing the choke with the jet carburetor; The suction also brings down the diaphragm and the needle to the idling position, where they are held positively by the forked arm 18, as described. When the engine is cold and only then, the arm 18 is raised as described and in turn raises plunger 20 so as to take away entirely the function of spring 29. This act leaves spring 40 unopposed and its tension is sufficient then to overcome the downward suction of the diaphragm. The needle finds itself in the uppermost position under these circumstances and gives the required orificeopening for the proper richness of mixture to insure prompt and sure starting under all weather conditions. As soon. as the butterfly is opened for running conditions, arm 18 is manually (through arm 26) dropped down to .neutral position and held there by the cam mechanism described and spring 29 is again brought into functional relation with the diaphragm, and the needle can then be seen to be fluctuating with the draughts of the engine.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus which I now considerto represent the best embodiments thereof, but I desire to have it understood that the apparatus disclosed is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combinations and relations described, some of these may be altered and others omitted and some of the features of each modification may be embodied in the others without interfering with the more general results outlined, and the invention extends to such use.

What I claim as new is:

1. In a carburetor for internal-combustion engines, a throttle arranged in the air-intake, and means whereby idling air is taken from in front of the throttle and delivered to the mixingchamber, adjacent the fuel-inlet, the delivery means at the fuel-inlet consisting of a cupshaped disk in the bottom of which the inlet is formed, said disk being provided with a plurality of radial ports delivering air into said cup.

2. A carburetor embodying a needle-fuel-feed and devices for adjusting the, idling position of the needle, a throttle in the intake-side of the carburetor, and means whereby when said throttle is open the needle will be released from idling position and become subject to the pressure in the intake-manifold, said means embodying a diaphragm and counter-balancing springs on opposite sides thereof.

3. A carburetor embodying a needle fuel-feed and devices for adjusting the idling position of the needle, a throttle in the intake-side of the carburetor, and means whereby when said throttle is open the needle will be released from idling position and become subject to the pressure in the intake-manifold, said means embodying a bodily-adjustable diaphragm open at one side to the atmosphere and at the other side to suction, and counter-balancing springs on opposite sides of the diaphragm.

4. A carburetor embodying a needle fuel-feed and devices for adjusting the idling position of diaphragm is bodily adjustable together with.

the needle, a spring pressing the needle toward the diaphragm, and a counter-balancing spring arranged at the other side of the diaphragm.

5. In a carburetor, a mixing chamber having a main air inlet and a fuel inlet, a valve in said air inlet, a fuel valve in said fuel inlet, a diaphragm connected to said fuel valve for operation thereof, said diaphragm being exposed on one side to pressure conditions within said chamber and on the other side to the atmosphere, the arrangement being such that pressures in the chamber lower than atmospheric pressure tend to actuate the diaphragm to close said fuel valve, spring means tending to press said diaphragm outwardly against atmospheric pressure, an outer spring tending to press the diaphragm inwardly, and accessible means for adjusting the outer spring.

ERL V. BEALS.

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