US1811354A - Automatic choke for carburetors - Google Patents

Description

June 23, 1931. JQECK 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet 1 INVENTOR flomtfoeck,

ATTOR N EY June 23, 1931. DJJOECKY 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet 2 INVENTOR flaw/5,3 uzl' 2 7 7 ATTORNEY June 23, 1931. T. D. JOECK 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet s l/ll/ I I l 26 1 30 llllllll/IIIIIIIII INVENTOR fla r n53 fiec';

@ 92. ATTORNEY June 23, 1931. T. D. JOECK 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS v Filed Dec. 14, 1928 4 Sheets-Sheet 4 ATTORNEY Patented an. 23, 1931 STATES PATENT}; OFFICE THOMAS D. JOECK, 0F IBELMAIR, NEW JERSEY AUTOMATIC CI EI IOKE FOR CARBURETORS Application filed December 14, 1928. swarm. 325,992.

ing period; and the invention has reference, I

more particularly, to a construction of automatic choke forcarburetors of internal com-' bustion engines.

One object of the invention is to provide a choke of the above character that automatically varies the supply of air to the internal com-w bustion engine carburetor in accordance with therequirenientsof the engine. tr Another object of the invention lies in the provision of a choke of the above character "that controls the supply of air so that the mixture ofv fuel and air is such as to enable the engine to operate at the maximum of econ- 20 omy.

Still another object of the invention is to provide a choke of the above character that is of simple, strong construction and which is reliable in operation. o

Other objects of this invention, not at this time more particularly enumerated will be clearly understood from the following detailed description of the same.

. V The invention is clearly illustrated in the accompanying drawings; in which Fig. l is a view in side elevation with parts broken'away of an internal combustion engine carburetor equipped *with the novel automatic choke of this invention;

Fig. 2 is a sectional View taken along line 2-2'ofFig1; T

Fig. 3 is an enlarged vertical sectional view of the automatic choke illustrated in Fig. 1, the valve of said choke being illustrated in its closed position; 1 i

Fig. 4 is a view similar to Fig. 3 but is taken at right angles thereto and with the choke valve shown in partly open position;

Fig. 5 is a sectional view taken along line 5 of Fig. 4 looking in the directionof the arrows;

Fig. 6 is a sectional view taken along line 6-6 of Fig. 4; d

Fig. 7 is a view similar to Fig. 1 but illustrates amodified form of control;

Fig. 8 is a fragmentary view illustrating one step in the operation of the automatic choke; and V Fig. 9 is an enlarged sectional view oi a portion of the structure shown in Fig. 7.

Similar characters of reference are employed in all of the hereinabove described views, to indicate corresponding parts.

Referring now to said drawings, the reference character 1 designates an internal co1nbustion engine having a carburetor 2 equipped with the novel automatic choke of this invention. This automatic choke comprises a choke valve casin 3 having a cone shaped air discharge nipp e 4, the outer reduced end ofwhich is truncated and is adaptedto be positioned within the inlet opening of the carburetor air intake pipe 5. Valve casing 3 is illustrated as being of substantially rectangular cross-section and as being made up of a pluralit of plates secured together as by rivets. two flat side plates 6 and 7 riveted to the flange of-channel shaped front and rear plates 8 and 9. The ends of the casing 3 are closed by top and bottom plates 11 and 12, respecs tively. To and bottom plates 11 and 12 are secured to t e remainder of the casing by ver tically extending spacer rivets 10. Valve casing 3 is retained in desired position With re spect to the intake pipe 5 and issupported from this intake pipe by means of a pair of spaced bolts 13 that extend through apertures in the side plate? and in flanges of the front and rear plates 8 and 9 and also through apertures in a clamp 15 secured upon the in- 7 take pipe 5. Clamp 15 comprises upper and lower substantially V-shaped separable portions surrounding the intake pipe 5, which portions are retained" in clamping relation upon this pipe by bolts 14', as especially shown in Fig. 2. The bolts 13 by reason of their tension act to rigidly retain the reduced end portion of the nipple 4 within and in abutting relation to the end of the intake pipefi, thereby preventing leakage of air between these members. 1

The valve casing 3 is provided with a circular air inlet opening 16 extending through the bottom plate 12. The inner marginal ese plates comprise 1 edge portion of the bottom plate 12 surrounding the inlet opening 16 provides a valve seat 17 for a choke valve 18. Choke valve 18 is secured as by a pin 20 to a vertically extending plunger rod 21. The valve seat 17 is surrounded by an annular upwardly and outwardly flared airbaflie 22. Air baflle 22 is attached in fixed position upon the bottom plate 12 by means of oppositely arranged clips 23 (Fig. 8) that are soldered or otherwise secured to the outer surface of the bafiie and are'also riveted by spacer rivets 24 to the bottom plate. Spacer rivets 24 extend downwardly from the bottom plate and carry a cross-plate 25 at their lower ends. Crossplate 25 is centrally apertured to receive and support a dash-pot 26 extending downwardly from this cross-plate. A screw cap 27 is threadedv upon the upper open end of the dash-pot 26 and abuts the upper surface of the cross-plate 25, causing the lowersurface of this plate to abut an annular shoulder formed on the dash-pot 26, thereby effecting a rigid connection between the cross-plate and dash-pot.

The lower portion of plunger rod 21 extends through a central aperture in the screw-cap 27 and has a loose fitting check piston 28 threaded upon its lower end. Check piston 28 is provided with a plurality of apertures 30 extending therethrough, which apertures are normally closed by a relief valve 31 that is slidably mounted upon a sleeve 32 surrounding the plunger 21. A washer 33 is supported upon the top of sleeve 32 and carries a compression spring 34 that bears at its upper end against a washer 35 and tends to urge thecheck piston clownwa'rdly and also'actsto check the upward movement of the check piston '28 as this piston approaches the top of the dash-pot. The dash-pot 26 is filled with a suitable liquid such ,as lubricating oil and a felt washer 36 is positioned between screw-cap 27 and washer 35 for retaining this liquid within-- the dash-pot.

A piston 37 having a piston ring 38 is formed upon the upper end of the plunger rod 21. Piston 37 is adapted to reciprocate within a pneumatic cylinder 40 that has its lower open end portion extending through an aperture in the top platell. A nut 41 is threaded upon the cylinder 40 and abuts the lower side of the top plate 11 causing the upper sideof this plate to abut an annular shoulder formed on pneumatic cylinder 40, thereby rigidly securing this cylinder to the top plate. A cylinder head 42 is threaded upon the upper end of cylinder 40. Cylinder head 42 has a port 43 extending from the interior of the pneumatic cylinder through a nipple 44 to a'pipe or tube 45 that is connected to the intake manifold 46 of the internal combustion engine 1. A felt lubrieating washer 47 is mounted upon the plunger rod 21 adjacent the piston 37: Washer 47 isadapted to supply suitable lubricant to the inner walls of cylinder 40.

The front plate 8 of valve casing 3 is provided with a substantially square opening or window 49 that is adapted to be closed by a gate valve 50. Gate valve 50 is provided with a rectangular aperture 51 throughwhich acatch 52 is adapted to Extend. Catch 52 has substantially the shape of a sector and is provided with a pair of spaced recesses 53 and 54 in its upper arcuate edge. The outer portion of this arcuate edge is knurled at 55 and the inner portion is extended to form a catch-finger 56. Catch 52 is fixedly mounted, at substantially the geometrical axis of its arcuate edge, upon the free end of a coil spring 57. Coil spring 57 is wound around a pin 58 protruding from the gate valve and has its other end fixed to the gate valve as by'extending through an aperture therein. Spring 57 urges the catch 52 upwardly and normally holds either recess 53 or recess 54 in cooperating engagement with the upper wall of aperture 51 as especially .shown in Fig. 4.

By suitably pressing down as with the thumb upon the knurled portion 55, the

catch 52 may be turned so as to cause either recess 53 or recess 54 to engage the upper 'wall of aperture 51 as desired. With, the

gatevalve 50 closed as illustrated in Fig. 4, when recess 54 engages the upper wall of aperture 51, the catch finger 56 projects into the vertical path of movement of the choke valve 18 at a'certain height above the air inlet opening 16, and when the catch 52 is moved so that the recess 53 engages the up per wallet aperture 51 then this catch finger is out of the path of movement of the choke valve and is positioned as shown by dotted lines in Fig. 4. p

The gate valve 50 is hingedl a pin 60 supported at its ends by the flanges of the front plate 8. An operating pin or lever .61 is secured at its inner end to the gate valve 50 and has its outer end connected to a link 62. Upward movement of link 62 causes gate valve 50 to turn about its hinge pin 60 opening the window 49 and permitting air to enter the valve casing through this window. Movement of link 62 is obtained in the structure shown in Fig. 1 by connectingthe upper end of this link to a crank 63 which in turn is connected to a suitable push-pull handle mounted on the dash by a link' 64. In the form of the invention shown in Fig. 7, link 62 is connected to one arm of a bell crank lever 65 that is fulcrumed upon a thermostatic bellows casing 66. The other arm of the bell crank lever 65 engages the bottom of a recess 67 formed in the outer end of a plunger 68. Plunger 68 extends inwardly of the casing 66 and has a disk shaped inner end retained in engagement with a thermostatic bellows 70 by. a compression mounted on spring 71. Two such thermostatic bellows 70 are illustrated as arranged in series in the casing 66 but it is obvious that. any number of these bellows may be employed as desired. These thermostatic bellows contain a suitable volatile liquid and are adapted to expand upon the heating of engine land effect through movementof bell crank lever and link 62 the opening of the gate valve 50.

In operation, when the engine 1 is dead, the choke valve 18 is in engagement with its valve seat 17,.thereby closing the air inlet opening '16 of the choke valve casing 3. As soon as the engine 1 starts to turn over, however the suction developed in the intake manifold 46 creates a region of reduced air pressure within the choke valve casing 3 and above the closed choke valve 18, and also in the pneumatic cylinder 40 above the piston 37. Choke valve 18 and piston 37 thereupon move upwardly owing to the action of the unbalanced air pressure on their under surfaces. As these members commence to move upwardly, the plunger rod 21 moves upwardlytogether with check piston 28. The relief valve 31 acts to close the apertures 30 of the check piston 28 during this upward movement, making it necessary for the liquid in dash-pot 26 in. order to pass the loose fitting check piston, to flow between this piston and the walls of the dash-pot, thereby causing the plunger rod to have 'a relative slow upward movement. This results in a gradual upward movement of choke valve 18 away from its seat 17 cansing a gradual increase in the volume of air supplied through choke valve casing 3 to the carburetor by way of intake pipe 5. .This is desirable as it prevents a to rapid inflow of air just at the starting of the engine which would tend to stall the same owing tothe presence of too lean a mixture. Just as the choke valve leaves its seat, the relatively small volume of air admitted results in an extremely rich mixture supplied the engine which is desired in starting. The bafie 22 coperates with the choke valve 18 in restricting the rate of increase in the inflow of air to a desired value. Were this baflle not present, a maximum inflow of air would take place almost immediately upon the opening of the choke valve. The continued upward movement of the plunger rod 21 is soon arrested by the choke valve 18 contacting with the catch finger 56 of the catch 52. Catch finger 56 stops the upward movement of the choke valve, thereby causing the engine to operate under a partially choked cbndition. As the engine becomes warm, the thermostatic bellows expand and effect the opening of gate valve 50. As gate valve 50 commences to open, the catch finger 56 is withdrawn from engagement with the choke valve, thereby permitting this valve to continue its upward movement and ending the choking action thereof. Choke valve 18 and plunger 21 continue their upward movement resulting from the suction in pneumatic cylinder 40 until compression spring '34 in dash-pot 26 checks the same thereby gradually bringing these members to rest. The removal of the choke valve from the vicinityof the bathe-22 and the opening of gate valve 50 automatically ends the choking action of the choke valve.

Should the engine 1 for any reason tend to stall after the choke valve is partially or completely open, the suction in the pneumatic cylinder 40 will fail and the choke valve and plunger rod will fall sufficiently under the action of spring 34 and gravity to check this tendency by increasing the choking action of the automatic choke, resulting in a richer mixture and the continued operation and pick-upof the engine. The upper surface of catch finger 56 is beveled so as not to prevent the free downward movement of the choke valve. \Vhen the downwardly moving choke valve strikes the beveled upper surface of the catch finger, the catch 52 is forced outwardly opening the gate valve 50 slightly during the passing of the choke valve. After the passage of the choke valve, the gate valve closes under the action of gravity which closing action may be assisted by a spring, if desired.

It will be noted that the dash-pot 26 does not restrict the free downward movement of the choke valve and plunger rod in accordance with pressure variations in cylinder 40, for during such downward movement, the relief valve 31 is open as shown in Fig. 4 permitting liquid to flow readilythrough the apertures inrheck piston 28. In other words, when the automatic choke of this invention is employed, the choking of the engine is varied automatically in accordance with the requirements thereof, thereby eliminating possible stalling and consequent restarting thereof.

In the event that the gate valve 50 is operated manually from the dash instead of using the thermostatic bellows, it is merely necessary to operate this valve after the engine at either of two positions by use of the recesses 53 and 54, the temporary partial open ing of the choke valve, effected when recess 54 is used and while the engine is warming up, can be "eliminated in warm weather, if desired, by using the recess 53. The catch 52 may be eliminated altogether if desired, in which case the automatic action of piston 37 and the choke valve 18 will sufiice to automatically choke the engine. In such case it will be apparent that when the engine starts, the choke valve will rise gradually under the restrictive action of the dash-pot until the valve is completely open. If the engine should tend to stall during the starting operation, the choke valve will drop sufl'iciently to correct such tendency. In the event that the catch 52 is not" employed, the gate valve 50 will still serve the function .of relieving excess pressure developed-in the choke valve casing such as that caused by back fir- 1n Inasmuch as the novel automatic choke of this invention supplies just the amount of air necessary for the most efficient operation of the engine, both at starting and under continued' working conditions, it will be apparent that the employement of the device of this invention eliminates flooded carburetors and prevents waste of fuel and dilution of crank-case oil.

As many changes could be made in the above construction and many apparently widely diflerent embodiments of this invention could be made Without departing from the scopethereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limitin sense.

Vl hat is claimed'is 1. In combination with a carburetor, choking means for regulating the supply of air to said carburetor, said choking means comprising asyalve automatically operated in response to variations, in the Vacuum applied to said carburetor, and dash-pot means for retarding any decrease in the choking effect of said valve, but offering substantially no resistance to an increase in the choking efiect. thereof.

2. In .combination with a carburetor, a choke comprising, a choke v'alve, a casing having an air lnlet opening controlled by said choke valve and an air outlet opening connected to said carburetor, a plunger connected in driving relation to said choke valve, a pneumatic cylinder communicating with the vacuum applied to said corburetor, a piston operating in said pneumatic cylinder and connected to said plunger, said piston being actuated in accordance with the degree of vacuum applied to said carburetor for effecting the operation of said choke valve, a gate valve connected to said casing and thermal means for effecting the opening of said gate valve valve.

3. In combination with a carburetor for an internal combustion engine, a choke comprising, a'choke valve, a casing having an air inlet opening controlled bysaid choke valve and an air outlet opening connected to said carburetor, a plunger carrying saiid choke valve, a pneumatic cylinder communicating with thevacuum applied to said carburetor, a piston operable in said pneumatic cylinder and connected to said plunger for effecting the operation of said choke valve in accordance with \the degree of vacuum applied to to thereby by-passsaid choke said carburetor, a gate valve mounted on said casing for closing an opening adapted to by pass said choke valve, and a catch carried by said gate valve and adapted to r%trict the opening of said choke valve.

4. In combination with a carburetor for an internal combustion engine, a choke comprising, a choke valve, a casing having an air inlet opening controlled by said choke valve and an air outlet opening connected to said carburetor, a plunger carrying said choke valve, a pneumatic cylinder communicating with the vacuum applied to said carburetor,

a piston operable in said pneumatic cylinder and connected to said plunger for effecting the operation of said choke valve in accordance with the degree of vacuum applied to .said carburetor, a gate valve mounted on said casing for closing an opening adapted to by-pass said choke valve, and a catch carried by said gate valve and adapted to restrict the opening of said choke valve, and means for opening said gatevalve to thereby remove said catch from operable connection with said choke valve so as to permit the full opening of the latter. a

5. In combination with a carburetor, a choke comprising, a choke valve, a casing having anair inlet opening controlled by said choke valve and an air outlet opening connected to said carburetor, and pneumatic means connected with said-choke valve and actuated in accordance with the degree of vacuum applied to said carburetor for effecting the operation of said choke valve and a liquid dash-pot connected to said choke valve for retarding the opening movement of

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