US2957685A - Carburetor deicing system - Google Patents

Description

Oct.- 25, 1960 Filed June 21, 1957 F- W. COOK ETAL CARBURETOR DEICING SYSTEM 3 Sheets-Sheet 1 I N VEN TOR.

FORREST W.COOK JAMES E. EBERHARDT @WMW' AT TOR NEY Oct. 25, 1960 F. w. COOK ETAL 2,957,685

i CARBURETOR DEICING SYSTEM Filed June 21 1957 3 Sheets-Sheet 2 INVENTOR.

FORREST W. COOK JAMES E. EBERHARDT ORNEY Oct. 25, 1960 F. w. cooK ETAL CARBURETOR DEICING SYSTEM Filed June 21, 1957 3 Sheets-Sheet 3 54 as T1 .289 86 82 86 7798 77 I 77 '& %''I )Q Q 7.; I ///////1\ 76 e7 INVENTOR.

FIG 8 FORRESTWCOOK BY JAMES E. EBERHARDT fiMm/m ATTORNEY United States Patent 2,957,685 CARBURETOR DEICING SYSTEM Forrest W. 'Cook, and James E. Eberhardt, Trenton, Mich., assignors to ACE Industries, Incorporated, New York, N.Y'., a corporation of New alersey Filed June 21, 19-57, Ser. No. 667,111

1 Claim. (Cl. 261-129)v This invention relates to carburetors for internal combustion engines and, more particularly, to means for reducing or preventing the formation of ice on and around the throttle valve.

During cool, humid weather, the evaporation of gaso line during carburetion causes ice to form on the throttle valve, the mixing conduit, and the idle ports. When the throttle valve is moved to near idleposition, the ice formation bridges the space between the throttle valve and the wall of the mixing conduit, and causes stalling of the engine.

As the formation of'ice in the carburetor usually occurs when the throttle valve is in idle or near idle positions, due to the rapid expansion of the fuel-air mixture posterior to the throttle valve, it is an object of the invention todirect heated air into the mixing conduit adja cent the throttle valve when the latter is in idle or near idle positions to thereby reduce icing and prevent stalling of the engine.

Another object of the invention is to provide means for forming and discharging a heated fuel-air mixture toward the posterior side of a throttle valve when the latter is in slightly open position.

A further object of the invention is to draw heated air from a suction responsive device in an automatic choke control housing into an idling fuel passage to heat the fuel passing therethrough during idling of the engine.

The invention embodies other novel features, details of construction, and arrangement of parts, which are hereinafter set forth in the specification and claim, and illustrated in the accompanying drawings, wherein:

Fig. 1 is an elevation view, partly in section,.illustratin a stove, and a carburetor embodying features of the invention.

Fig. 2 is a fragmentary schematic sectional elevation view taken in the direction of the arrow in Fig. 1.

V Fig. 3 is a fragmentary sectional view takenalongthe line 3-3 ofFig. 2. V

Fig. 4 is a fragmentary sectional view taken along the line 44 of Fig. 3.

Fig. 5 is a schematic view illustrating a modified form of the invention.

Fig. 6 is a fragmentary vertical sectional view.

Fig. 7 is a fragmentary bottom view.

Fig. 8 is a fragmentary sectional view taken along the line 8-8 of Fig. 7.

Referring now to the drawings for a better understanding of the invention and, more particularly, to Figs. 1 to 4 therein, a downdraft carburetor is shown as comprising an air horn section 6, a main body section 7, and an outlet section 8 having a flange 9 for attachment to an intake manifold 11. The air horn section has an air inlet passage 12 communicating with a mixing passage 13 provided in the body section 7 and outlet section 8.

A constant level float bowl 14 on the body section 7 is provided with the usual inlet needle valve 16 controlled by a float 17. A fuel metering orifice 18 controlled by a 2,957,685 Patented Oct. 25, 1960 metering rod 19 leads from the float bowl to main fuel passage 21 having a nozzle 22 disposed to discharge fuel into a primary venturi tube 23.

An idling fuel system is shown as comprising a passage 24 leading upwardly from the main fuel passage 21 and having an idle orifice tube 26 communicating with a passage 27 leading to a vertically elongated idle port 28 and an adjustable idle port 29 having an idling adjustment screw 31. A metering restriction 32 is provided in the passage 27, and an air by-pass 33 leads to the passage intermediate the orifice tube 26 and said restriction.

A choke valve 34 is fixed on a shaft 36 journaled in the horn section 6, one end of said shaft projecting into a choke control housing 37 having a partition 38 and cover 39 secured thereon by means of screws 41. A bifurcated stud 42 is fixed on the cover to receive and engage the inner end of a spirally wound bimetallic thermostat 43, the outer end of the thermostat engaging the end of a crank '44, which is fixed on the shaft 36 and projects through an arcuate slot '46 in the partition 38.

A cylinder 47 is provided in the housing 37 to receive a piston 48 connected to the crank 44 by a link 49. A suction passage 51 leads from the cylinder 47, below the piston 48, to a suction port 52 in the wall of the mixing conduit 13 posterior to the edge of a throttle valve 53 when the latter is in its idle position. A stove 54, having an air inlet 56- and air outlet 57, is mounted on an exhaust manifold 58 to supply heated air through a conduit 59 to a control housing inlet 61 and thence into the chamber between the partition 38 and cover 39. A bypass groove 62 is formed in the wall of the cylinder 47 for the passage of heated air from the housing 37 to the passage 51 when the top of thepiston 48 is in the cylinder 47 far enough to uncover the top of groove 62. An idle bleed branch passage 45, having a restricted orifice 50, leads from the suction passage 51 to the idle passage 27.

The throttle valve 53 is fixed on a shaft 63 journaled at its ends in the outlet section 8, and is connected through a suitable link and lever arrangement to a manually operable accelerator pedal.

In the operation of an internal combustion engine provided with a carburetor of the type thus shown and described, the thermostat 43 acts through the crank 44 to yieldably resist opening movement of the choke valve 34 when the engine is cold, and permits free opening moven'ientof the choke valve when the engine attains its proper operating" temperature.

Upon starting of a cold engine, engine suction is applied through the suction port 52 and the idle ports 28 and 29 to create a suction in passage Sland cylinder 47, drawing the piston 48 into the cylinder until the top of the piston has uncovered the top of groove 62, thus effecting the initial opening or pull-01f of choke valve 34. As the engine warms up, heated air from stove 54 is drawn across the thermostat '43 causing it to expand, the piston 48 is constantly urged downwardly by suction, and the choke valve gradually moves to its full open position.

When the throttle valve 53 is in idle position, as shown in Figs. 1 and 4, intake manifold suction draws heated air from the stove 54 into the choke housing 37 and through the bypass groove 62 into the suction passage 51. Some of the heated air is discharged through the port 52 into the mixing conduit 13 posterior to the throttle valve, and the remainder of the heated air passes from the suction conduit 51 through the idle bleed branch passage 45 and restricted orifice 50 into the idle passage 27 to mix with and heat the idle fuel passing therethrough for discharge through the idle ports 28 and 29. By employing the heated air passing from the choke housing to heat the idle fuel and throttle valve, icing of said valve and the mixing conduit is materially reduced or prevented.

Figs. 5 through 8 illustrate two primary mixing conduits of a two-stage, four barrel carburetor embodying a modified form of the invention. The carburetor is shown as comprising an air horn section 66 and a body section 67, the latter having two primary mixing conduits 68 provided with venturi tubes 69 to receive fuel from main fuel nozzles 71. A choke valve 72, provided in the air horn section 66, is operatively connected to an automatic choke control mechanism 73 by a suitable conventional linkage (not shown). Primary throttle valves 74 are disposed in their respective mixing conduits 68 and fixed on a common shaft 75 adapted to be manually operated from an accelerator pedal.

Each primary mixing conduit 68 is provided with an idling fuel system comprising an idle passage 76 leading from a fuel bowl to idle ports 77 and 78, the port 78 being provided with an adjustment screw 79. The body. section 67 is adapted to be secured to an intake manifold 11 to form a plurality of hot air chambers 81, 82 and 83 interconnected by passages 84 and 85, for warming the walls of the mixing conduits 68. Each idle passage '76 is connected to the chamber 82 by a hot air idle bleed passage 86.

An automatic choke control mechanism 73 of the type heretofore described is shown as comprising a choke housing 87 having an inlet 88 to receive heated air from a stove on an exhaust manifold. When the throttle valves 74 are in idle or near idle positions, all the heated air is drawn from the choke housing 87 through a passage 89 and restricted orifice 91 into the hot air chambers 81, 82 and 83 for discharge through the passages 86 into their respective idle passages 76 to mix with and heat the fuel passing therethrough. By discharging a heated idling fuel mixture through the idle ports 77 and 78 into the mixing conduits adjacent the throttle valves, it has been found that engine failure due to icing is prevented.

An important feature of the present invention is to pro vide a carburetor choke control arrangement in which the drawing of heated air from the choke control mechanism into the idle fuel system and the mixing conduit to reduce icing does not adversely affect the operation of the piston inopening the choke valve when the throttle is in idling tion actingon the choke piston, plus the additional quan; tity of heated air drawn across the choke thermostat, permits the choke valve to open slightly more, providing additional air for fast or off idle operation, as fully described above.

Another important feature of the invention resides in a carburetion system adapted to provide a smooth, stable idling operation of an engine by bleeding heated air into theidling fuel system to maintain a more uniform tem: perature.

While the invention has been shown in but two forms, it is obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departingfrom the scope of the invention as defined in the claim.

We claim:

A charge forming device for an internal combustion v engine comprising a body'portion having a mixture con- 3 connected to said choke valve and tending to close said choke valve with a force that decreases with increase in engine temperature; a suction device in said body portion responsive to engine vacuum operatively connected to said choke valve tending to open said choke valve when said engine is running; a remote source of engine heat; a

heat passage connecting said remote source of engine heat, said housing, and said suction responsive device and discharging into said mixture conduit at a point posteror said throttle valve; an idle fuel system in said body portion for-supplying regulated amounts of fuel from said main position, due to the increase in suction posterior to the throttle during idling. When the throttle is moved from idle toward open position, the idle ports are unrestricted by the throttle to therebyincrease the suction within the suction passage leading to the choke housing cylinder below the suction piston therein, and increase the quantity i 2 of heated air drawn into the mixing conduit through the idle ports, rather than reducing the quantity of heated air drawn into the mixing conduit, as occurs with a conventional choke control suction line discharging posterior to the throttle valve. Therefore, additional heated air is provided when icing is most likely to occur, that is, at fast or on idle operation, and obviously the increased sucfuel supplyto said mixture conduit to a vertically elongated port adjacent said throttle valve and to an adjustable idle port spaced from said first port and generally laterally of said heat passage discharge in said mixture conduit; and a passageway in said body portion connecting said continuous passageway and said idle fuel system for-supplying heated air to said idle fuel system, said lastnamed ,passageway having a restricted orifice formed therein, whereby additional heated air is provided during fast idle operation.

- References Cited in the file of this patent UNITED STATES PATENTS 2,269,706 Brown Jan. 3, 1942 2,429,781 Udale Oct. 28, 1947 2,684,058 Boyce July 20, 1954 Sutton, Oct. 4, 1955

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