US2155754A

US2155754A - Gas carburetor

Info

Publication number: US2155754A
Application number: US719872A
Authority: US
Inventors: Roy F Ensign
Original assignee: ENSIGN CARBURETER CO Ltd
Current assignee: ENSIGN CARBURETER Co Ltd
Priority date: 1934-04-10
Filing date: 1934-04-10
Publication date: 1939-04-25
Anticipated expiration: 1956-04-25

Description

R. F. ENSIGN GAS CARBURETOR April 25, 1939.

Filed April 10, 1934 Even/qr. Roy. E Erzsyru.

Patented Apr. 25, 1939 UNITED STATES GAS cAnBURE'ro'n Roy F. Ensign, San Marino, CaliL, assignor to Ensign Carburetor 00., Ltd., Huntington Park, Calif., a corporation of California Application April 10, 1934, Serial No. 719,872 '15 Claims. (01. 48-180) This invention relates to gas carburetors; and one of the general objects of the invention is to provide a carburetor so constituted and so functioning that it will be capable of operating when supplied with gas at a normal pressuregless than atmospheric; or less than that at which the carburetor is supplied with air. And it is a general object of the invention to provide a simple mechanism which will accurately proportion the fuel throughout the range of operation and automatically stop the flow of gas whenever the engine stops operation.

In Patent No. 2,073,299, granted March 9, 1937, on Gas carbureting apparatus, I have described a carburetor and gas regulator apparatus of somewhat difierent type and which in general accomplishes the same objects; and in certain broad features the arrangement shown in this present application is similar to that of my prior application. In other particular features, however, and particularly with regard to the arrangement for automatically causing gas flow when the engine is in operation, the present invention provides a difierent specific structure and action for accomplishing the same general purposes. There are also certain novel features in connection with the economizer control which will be explained hereinafter.

30 One of the difliculties encountered in the operation of any carburetor on gas at low pressure lies in the fact-that the motor will not idle at low speeds because the venturi, when large enough to accommodate the air flow for maxi- 35 mum power, is too large to create a sufficient suction at low speeds to draw the required amount of gas from a regulator which has been set to deliver at sufiiciently below atmosphere to insure that its valve will close when the suction 40 on itlgi, outlet ceases. Another difficulty is that the gas pressure at the carburetor gas intake usually varies one hundred per cent or more because of the varying inlet pressures on the regulator. While regulators are known which 45 will deliver a substantially uniform pressure with varying iinitial pressures, the average regulator in'use does not do that, and delivers a varying regulated pressure on account of the varying initial pressure in gas mains, or the varying pres- 50 sures obtainable from the very commonly used tanks of liquid petroleum gasjin which the pressures vary ,greatly with temperature changes. Such changes in the gas pressure supplied to the carburetor make it very difficult to maintain 55 a combustible mixture ratioproperly through v the operating ranges of the engine, and particularly at low speed idling operation.

The present invention overcomes such difilculties by providing an'automatic proportioning means in-connection with the venturi, which will 5 cause the provision of the proper mixture for starting, and idling at low speeds, and for oper-v ation through the other operating ranges, regardless of the varying sub-atmospheric pressure of the gas supply. This is done by so placing a floating air valve that it forms a yielding obstruction in the air flow to the venturi. By utilizing a diaphragm tending to close the floating air valve, and by applying to that diaphragm u the pressure of the gas supplied to the carburetor,

a balance of forces is set up which insures atall times a proper proportioning of the air and the gas supply.

A carburetor in'typical and illustrative embodiment of the present invention, and in association with the gas regulator typical of any gas regulator, but having certain special features hereinafter described, is shown in the accompanying drawing, in which:

Fig. 1 is a view, predominantly in central vertical section, illustrating the carburetor and its association with the regulator;

' Fig. 2 is-a detail cross section of the carburetor taken on line 2-2 of Fig. 1; and I Fig. 3 is a detail cross section of the carburetor taken on line 3-3 of Fig. 1;

The carburetor here illustrated has a suction passage generally indicated by the numeral l0, containing the usual throttle II, a venturi I2 and anair'. inlet Hi, the upper end of the suction passage being adapted to connect with the engine manifold (not shown). These features are all typical; their particular design is of no moment in my invention, and the venturi may be substituted by any device which creates a fuel inspiring depression by reason of air velocity. Formed in the carburetor casting are gas inlets l4 and I5, one of which, I5, is controlled by the adjustment needle Hi; the other two of which M, are threaded and may be plugged, as indicated at Ma, for larger adjustment. controls of the gas inlet, depending upon the B. t.- u. content of the gas being used. These gas inlets are shown as fed by the pipe connection ,l! which leads from the outlet of regulator R; and the inlets feed into a substantially annular passage l8 that surrounds the venturi. The venturi has at its throat the gas inlet orifices l9.

, The economizer arrangement includes a balance passage 26 communicating with air inlet l3 through, a calibrated bore 2|. In the construction as-here shown a screw plug 22 holds throttle controlled suction in the main suction passage below the throttle.

A sliding valve 21 occupies valve bore 25, this valve having a hollow interior 28 which, v'ia port 29, is always in communication with port 26. A light spring 21a holds the valve normally in the position shown in Fig. 3, and in this

position passages

20 and 24 are in open communication with port 26. Valve bore 25 extends to the right of passage 24, as illustrated at 250; so that when valve 21 is moved over to the right in Fig. 3 it gradually and then finally cuts off communication of

passages

26 and 24 with port 26.

Valve 21 has a projecting stein 36 which is engaged by lug 3| mounted on throttle shaft 32, when the throttle is moved toward and to wide open position. Thus, as the throttle approaches and then finally reaches wide open position, valve 21 is moved to cut off communication of port 26 with

passages

24 and 20. 7

Leading off from

passages

20 and 24 is a tube 35 that goes to the upper chamber 36 of regulator R, above its diaphragm 31. Passage 28 and the interconnecting pipe 35 form a balance connection between the air intake of the carburetor and a the reference pressure chamber ofregulator R.

idling operation when the depression (the amount by which the pressure is below atmospheric) is slight, the economizermay have little influence 'upon the reference pressure placed upon the regulator diaphragm. In order to prevent that slight depression from drawing air from the balance passage, spring seated :valve 26a may be inserted in passage 26; the spring 26b being strong enough to keep the valve seated against slight epressions but allowing the valve to open when the depression in the suction passage grows greater as medium running ranges are appreached. But as the throttle H opens'increasing the depression in the suction passagebelowthe throttle, an increasing depression is placed upon the balance passage from port 26 the effect of that depression in lowering the pressure in connection 35 being modified .by the inflow of air at the calibrated orifice 2 I. Then, as the throttle comes to full open position, movement of valve 21 cuts off the depression from port 26, so as again to put full intake pressure on the regulator diaphragm.

In the regulator here illustrated it will be noted that increase of the reference, pressure in chamber 36 tends to lower the diaphragm and to open the pressure controlling valve 40. The spring 4|,

adjustable in pressure by the regulation of plug 42, or by substitution of other springs, tends to close valve 40. This spring also, through the medium of the interconnecting arm 4211. supports the weight of diaphragm 31 and the interconnected parts. In normal operation spring 4| will be so set as to cause valve 40 to close surely and tightly .when atmospheric pressure is present in the regulator outlet; the outlet being connected via passage 43 with chamber 44 under diaphragm 31. Assuming that operation of the engine now applies suction to the outlet, pressure in chamber 44 is reduced, and the reference pressure in chamber 36 above the diaphragm opens the regulator valve 46. Under these conditions, variation in the reference pressure in chamber 36 will vary the pressure of gas delivery at the regulator outlet; and the action of the economizer in lowering the reference pressurethroughout the medium of running ranges of the engine (throughout medium throttle positions) will cause valve 40 relatively to close andthus relatively to decrease the delivery pressure of the outlet, and thus relatively to thin the mixture formed by the carburetor throughout medium operating ranges. As noted, this action of the economizer is slight at closed position of the throttle, so that the economizer In the lower part of the mainsuction passage there is a valve seat 50, and above it is a flare 5| in the passage wall; so that the valve 52 which seats downwardly, or nearly seats, on seat 50,

can rise into the flared part of the passage, and thus increase, proportionately as it rises, the air passage around the valve. In its uppermost position, shown in dotted-lines in Fig. 1, the valve strikes the stop pin 53 at its position of widest opening.

A valve stem 54 carries valve 52 and slides vertically in the stem guide 55. The lower end of stem 54 rests on the head 56 of the bolt that secures the two plates 51 to diaphragm 58. Diaphragm 58 has above it chamber 59 in constant communication with the intake air pressure .via port 66; and below it the diaphragm has a chamber 6| which is in constant communication with the gas pressure at the carburetor inlet, via passage 62, tube 63, and port 64. The spring 65 supports diaphragm 58, the supporting pressure of the spring being adjustable by means of the adjusting screw 66. Spring 65 is in practice so adjusted that it practically balances the weight of the valve and the weight of the diaphragm, leaving only a suflicient unbalanced downward force that the valve will return to its normal lowermost position, seating or almost seating on valve seat 50, when the motor is not in operation. When the motor is cranked for starting, the

valve 52 rises and, assisted by the spring pressed diaphragm 56, floats on the air stream, and by checking the air stream reduces the pressure in the suction passage above the valve. This reduced pressure will of course be immediately communicated to the gas intake of the carburetor and thence, via port 64, connecting tube 63 and main passage; resulting in an increased depression in the passage above the valve, and again resulting in further downward movement of diaphragm 58'. The cycle of actions is thus cumulative; so that very quickly after the motor starts to turn over the pressure in the carburetor gas inlet will be reduced to-the pressure at or below that at which the regulator discharges. As soon as this condition has been reached, the regulatorvalve opens to feed in gas 'to' maintain the pressure at the carburetor inlet at an equilibrium point. The carburetor then begins to take gas through the Venturi ports, and the floating valve 52 continues to play its part in maintaining, at the Venturi throat, even during idling operation, the reduced pressure which is essential to drawing the gas into the throat. Immediately upon receiving the mixture the engine starts. During this condition of operation, at or near idling, valve 204 in the passage 20 prevents the depression above valve 52 from being passed on to the balance system and the regulator, where it would undesirably tend to affect the regulator action to lower the delivered gas pressure during idling.

As the throttle is opened to increase the-flow through the carburetor, valve 52 rises. So long as the engine is operating at idling or at low speeds, diaphragm 58 follows the valve upwardly; so that at all low speeds the valve is under the diaphragm control described. However, as the speed phragm, floating on the air current, until the air' valve strikes the limiting stop 53, which it does at moderate air velocities through the carburetor; and in this position it remains throughout the higher operating ranges. The upward movement of diaphragm 58 is limited, in this particular design, by the bolt head 56 striking the upper wall of the diaphragm chamber. The valve and stem must of course be sufficiently heavy to put the required restriction on the air stream to reduce the pressure as described. I find that the valve may be well made'of aluminum, the valve stem of steel; and the whole valve and diaphragm system operate nicely in equilibrium when the effective diaphragm area is equal to the horizontal area of valve 52.-

Whenever during the operation of the motor it is throttled down to low speed or idling, valve 52 lowers until it'again comes in contact with the diaphragm and comes again under diaphragmcontrol. With the motor warmed up screw 56 may be adjusted to adjust the idling mixture for the engine, and when this adjustment is made valve 52 will then stand in coring' at any time in the carburetor air intake,

and thus compensates the diaphragm action, just as balance port 2| compensates for the regula-' tor and economizer action, for any change in the intake pressure due to air resistance that may be caused by a heater or cleaner, or the like; p

It will be understood that in referring to at 75 mospheric andsub-atmospheric pressures-in the that the carburetor is being fed with air at at- 'mospheric pressure. If the air feed is at a different pressure, say a higher pressure, then the gas pressure at the carburetor will be correspondingly different, but always below the air pressure. The term atmospheric may thus be taken as meaning whatever air pressure the carburetor-is operating under. It is the relative difference in these pressures that concerns that part of the invention which causes lowering of pressure in the carburetor. The economizer arrangement, however, is operative regardless of whether the gas 'feed to the carburetor is at a pressure less-than that of the air feed, although in practice the gas feed pressure may always be less. I s

I claim:

1. A gas carburetor system for engines, embodying a carburetor having a suction passage with a suction outlet-and an air inlet and a throttle in the passage, means including a pressure regulator for feeding gaseous fuel to the passage at a point at the inlet side of the throttle and at a pressure less than that in the air inlet, a valvular obstruction in the suction passage tending normally to close the passage and capable of opening movement'by the air current flowing through thesuction passage, a diaphragm on the upper face of which the valvular obstruc- .tion rests, and gas pressure communication between the lower face of the diaphragm and the fuel feed.

-2. A gas carburetor system forengines, embodying a carburetor having a suction passage with a suction outlet and an air inlet and a throttle and a venturi in the passage, the throttle being toward the outlet from the venturi, means for feeding gaseous fuel to -the Venturi throat at a pressure less than that in the air inlet, a valvular obstruction in the suction passage at the inlet side of the venturi, tending normally to close the passage and capable of opening movement by the air current flowing through the suction passage, a diaphragm on the upper face of which the valvular obstruction rests, and a gas pressure communication between the lower face of the diaphragm and the fuel feed.

3. A gas carburetor system for engines, embodying a carburetor having a suction' passage with a suction outlet and an air inlet and a throttle and a venturi in the passage, the throttle being toward the outlet from the venturi, means for feeding gaseous fuel to the Venturi. throat. at a pressure less than that in the air inlet, the suction passage having therein an enlarge ment at the inlet side of the venturi, with a valve seat at the inlet end of the enlargement, a floating air valve adapted to seat upon said seat and adapted to be raised into the passage enlargement by the air stream flowing through the suction passage, a diaphragm 'on which the air valve rests when in closed position, a chamberat the upper side of said diaphragm communicating with air in the air inlet, and a chambar at the lower side of said diaphragm communicating with the fuel feed for transmitting the pressure of the fuel feed to the lower side of said diaphragm, and adjustable means for balancing the valve and diaphragm.

4. A gas carburetor system for engines, embodying a carburetor having a suction passage with a suction outlet and an air inlet. and a throttle in the passage, pressure regulator means for feeding gaseous fuel to the suction passage at apoint at foregoing specific descriptions, I have assumedthe inlet side of the throttle and at a regulated pressure less than that existent in the air inlet, means in the suction passage at the inlet side of the point of fuel feed acting to reduce the air pressure in the suction passage to a point below that of fuel delivery, said regulator including a pressure regulating valve, an actuating diaphragm and a reference pressure chamber at one side of the diaphragm, and means to transmit to said 10 reference pressure chamber the air pressure existent in the air inlet of the suction passage.

' 5. A gas carburetor system for engines, em-

bodying a carburetor having a' suction passage witha suction outlet and an air inlet and a throt- 15 tie in the passage, pressure regulator means for feeding gaseous fuel to the suction passage at a point at the inlet side of the throttle and at a regulated pressure less than that existent in the air inlet, means in the suction passage at the 20 inlet side of the point of fuel feed acting to rehe the air pressure in the suction passage to a int below that of fuel delivery, said regulator including a pressure regulating valve, an actuating diaphragm and a reference pressure chamber one side of the diaphragm, means to transmit so said reference pressure chamber the air pressure existent in the air inlet of the suction passage, and means for modifying that pressure'by suction from the suction passage. so 6. A gm carburetor system for engines, embodyin; a carburetor having a suction passage with a suction outlet and an air inlet and a throttle in the passage, pressure regulator means for feeding gaseous fuel to the suction passage at a ti? point at the inlet side of the throttle and at a regulated pressure less than that existent in the air inlet, means in the suction passage at the inlet side of the point of fuel feed acting to reduce the air pressure in the suction passage to 4,9 a point below that of fuel delivery, said regulator including a pressure regulating valve, an actuating diaphragm and a reference pressure cham- I ber at one side of the diaphragm, a pressure transmitting passage extending between the suctier: passage inlet and said reference pressure chamber, and a branch passage from said pressure transmitting passage communicating with the suction passage to apply suction to the pressure transmitting passage.

7. A gas carburetor system for engines, em-

cocsing a carburetor having a suction passage with a suction outlet and an air inlet and a throttie in the passage, pressure regulator means for feeding gaseous fuel to the suction passage at a 55 point at the inlet side of the throttle and at a regaciaed pressure less than that existent in the air inlet, means in the suction passage at the inlet side of the point of fuel feed acting to reduce the airpressure in the suction passage to as a point below that of fuel delivery, said regulator including a pressure regulating valve, an actuatdiaphragm and a reference pressure chamher at one side of the diaphragm, and a pressure communicating passage extending between the suction passage and the reference pressure chamer to apply suction to said chamber.

a. A gas carburetor system for engines, embodying a carburetor having a suction passage .with a suction outlet and an air inlet and a throt- 70 tie in the passage, pressure regulator means for feeding gaseous fuel to the suction passage at a point at the inlet side of the throttle and 'at a regulated pressure less than that existent in the air inlet, means in the suction passage at the 75 inlet side of the point of fuel feed acting to reduce the air pressure in the suction passage to a point below that of fuel delivery, said regulator including a pressure regulating valve, an actuating diaphragm and a reference pressure chamber at one side of the diaphragm, a pressure com- 5 municating passage extending between the reference pressure chamber and the suction passage at a point therein on the inlet side of the throttle, and valvular means actuated by throttle movement to control said passage.

9. In a gas carbureting system for engines, a carburetor having a suction passage with a suction outlet and an air inlet and a throttle valve in the passage, pressure controlling means for feeding gaseous fuel to the suction passage, and means for controllably varying the pressure upon the fuel feed to the suction passage; said means including a passage communicating with the suction passage at a point' at the air inlet side of the throttle and communicating with the fuel pressure controlling means to apply pressure thereto, a spring seated valve in said communicating passage and adapted to open the passage upon the' application of apredetermined amount of suction thereto from the suction passage, and a controlling valve in said communication passage adapted to be actuated by throttle movement to close said passage as the throttle approaches open position. 1

10. In a gas carbureting system for engines, a carburetorhaving a suction passage with a suction outlet and an air inlet and a throttle valve in the passage, pressure controlled means for feeding gaseous fuel to the suction passage at a controlled pressure less than the air pressure existent in the air inlet, means in the suction passage at the inlet side of the point of fuel feed acting to reduce the air pressure in the suction passage to a pressure below that of the fuel feed, means for controllably varying the pressure upon thefuel 40 feed to the suction passage, said means including a passage communicating with the suction passage at a point at the air inlet side of the throttle and communicating with the fuel pressure controlling means to apply suction thereto, and a valve in said passage adapted to open when a predetermined amount of suction is applied thereto from the suction passage.

-11. In a gas carburetor for,engines, a body having vertically extending suction passage therethrough with an upper suction outlet and a lower air inlet and with a throttle valve and a venturi in the passage, the throttle valve being toward the outlet from the venturi, a fuel feed passage leading to the Venturi throat, an enlargement in the 5 suction passage below the venturi and a valve seat at the base of said enlargement, a vertically movingair valve adapted to seat on said valve seat and to float on the air stream passing through the suction passage, 'a valve controlling diaphragm mounted in the body below the air valve and'having diaphragm chambers above and below the diaphragm, the upper diaphragm chamber communicating with the air inlet, an adjustable supporting spring beneath the diaphragm, andcom- 5 munication between the lower diaphragm chamber and the fuel feed.

12. In a gas carburetor for engines, a body having vertically extending suction passage therethrough with an upper suction outlet and a lower moving air valve adapted to seat on said valve seat and to float on theair stream passing through the suction passage; ax diaphragm mounted in the body below the air valve and on which diaphragm the air valve freely rests, and said diaphragm having a limited upward movement less than the upward movement of the air valve, a chamber in the body above the diaphragm and in communication with the air inlet, a chamber in the body below the diaphragm and in communication with the fuel feed, andan adjustable supporting springbelow the diaphragm tending to support the diaphragm and valve.

13. A gas carburetor system, embodying a carburetor having a suction passage with a suction outlet and an air inlet and a throttle in the passage, means for feeding fuel to the passage at a point at the inlet side of the throttle and at a pressure less than that in the air inlet, a valvular obstruction in the suction passage at the'air inlet side of the point of fuel feed tending normally to close the passage and capable of opening movement by the air current flowing through the suction passage, and means, independent of the air current movement of the obstruction,whereby the pressure existent atthe fuel feed tends to move the obstruction in opening movement direction.

14. A gas carburetor system, embodying a carburetor having a suction passage with a suction outlet and an air inlet and a throttle in the passage. means for feeding fuel to the passage at a point at the inlet side of the throttle and at a pressure less than that in the air inlet, a valvular choke means positioned in the suction passage at the air inlet side of the point of fuel feed, said valvular choke means adapted to be opened by decrease 'of pressure in the suction passage between said choke means and the throttle, and

means, acting independently of said last mentioned choke opening actuated by the pressure of the fuel at the point of fuel feed and tending to open said choke means witha force which is a function of the fuel feed pressure.

15. In a gas carbureting system for engines, a

- carburetor having a suction passage with a suction outlet and an air inlet' and a throttle valve in the passage, pressure controlled means for feeding gaseous fuel to the suction passage, and means for controllably varying the pressure upon the fuel feed to the suction passage, said means including a passage communicating with the fuel pressure controlling means to apply thereto a pressure substantially equal to that existent at the air inlet, and including also a passage communicating with the suction passage. at a point at the air inlet side of theithrottle and communicating with the fuel pressure controlling means to apply suction thereto, and a controlling valve in said last mentioned communication passage adapted to be actuated by throttle movement to close said passage as'the throttle approaches open position. so

ROY I". ENBIGN.