US2074729A - Carburetor - Google Patents

Description

Mmhzs, 41937.

\ s. F. HUNT 2,074,729

CRBURETOR Filed Jan. l`6, 1933 IN VEN TOR.

. 5m# E Hum Patented Mar. 23, 1937 V `uNlTlzl) sTATlzs PATENT ol-"Flce CARBURETOB Scott F. Hunt, Detroit, Mich., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware npplieauonuanuary 16, 1933, serial Nassau `4 claims. (ci. 12a- 119i This invention relates to carburetors, more es- Figures 3 and 4 `are views similar to Figure2 pecially to automatic choke valve control mecha# but showing modified forms of the invention; `nisms therefor, and has for its principal object and i l the provision of an improved thermostat control Figure 5 is a detaiiview of a spacing collar. 5 for amechanism of this kind. i l l Referring now to the drawing in more detail, 5 Internal combustion engines using liquid fuel Vthe carburetor ill is a down draft plain` tube carrequire a richer mixture when the engine is cold i buretor having a choke valve i2 located in the air than when it is hot. Carburetors for forming l intake horn I3, and a throttle Il controlling the this fuel mixturev are provided with a control mixing chamberli. The casing is flanged at i6 l valve, usually an `air supply regulating valve or to facilitate mounting the carburetor on the in- 10 l choke, which is adjustable to regulate the richtake manifold i1 of the engine. The choke valve ness of the mixture. Certain prior art devices, of control mechanism, indicated generally at 20, which the copending application of S. F. Hunt, is iixed upon the manifold adjacent to thercar- `Serial No. 653,518, filed January 25, 1933, is an buretor.` It is to be understood that the specific l example, provide a control mechanism for addiarrangement shown is shown by way of example 15 `tion to or incorporation in the carburetor to autoonly as the invention may be applied to other maticaily control the choke valve to produce a types of carburetors and the control mechanism mixture varying in richness inversely as the enmay be incorporated in the carburetor structure, l h gine temperature. Thiscontrol is regulated by a within the` teachings of the present invention. thermo-stat which is usually mounted in juxta- The choke valve I2 is mounted by a Shaft 22 20 position to the exhaust manifold of the i engine which carries a lever 24 through which the choke and heated thereby. The automatic control deis moved. Thefree endof the lever 24 carries a vice may be locked in operated position when the' rod 26, pvtally `Sllled thereto, and the other `engine is at normal operating temperature, so end of this rod is pivoted to a. lever 28 `that is that the mixture then delivered to the engine is fixed upon a thermostat shaft 30. `The choke 25 regulated by the carburetor adjustments rather valve I2 is of the unbalanced type, that is to say, than by the choke valve, f `pressure `,difference between its faces tends to In certain instances the thermostat will be open the valve. This movement. of the valve is heated too rapidly by heat radiated directly from opposed by the Ytension of the thermostat 32, 30 the manifold when the engine isy started,` with which tension decreases as the temperature in- 30 the result that the richness of the mixture will CTBRSGS- The throttle lever lllmay, if desired. be be graded down too rapidly. The exhaust manioonoeotedrto the control unit 20 by a rod 33, fold, being composed of relatively thin metal, .as 'disclosed in the Hunt application above recools down rapidly and the thermostat may also ferred to. h cool down too rapidly when the `engine is stopped` The thermostat 32 is fixed at one end to the 35 or run at idling speed, with the result that, when `shaft 3U and at the other endto a casing 34 by the engine is restarted before it has had time to pin 35- The Casing 34 iS 013911 faced and is get cold or is brought up to a high speed after mounted concentrically of the shaft 30 on a boss idling, the mixture delivered `to it will be too rich. 3B which proieots from the housing ofthe con 40 The present invention teaches improving the `trol unit 20. The casing 34 is rotatable upon the 40 operation of the prior art devices by absorbing boss to adjust the tension of the thermostat, and a quantity of heat from the manifold during the is held in place by a suitable clamp and screw warming up period of the engine and dissipating indicated at l0. l

that heat during the cooling down period to alter The control mechanism is located so as to the operations of the thermostat, and provides bring the Openrface 0f the (5851118 u Opposite 45 `means for accomplishing this result. the exhaust manifold 42, but at some distance My invention will be best understood from the therefrom. The intervening space is filled by accompanying detailed descriptionof axpreferred a heat absorbing medium 44 shown as a block embodiment of it, reference being had to the of metal secured to the manifold by bolts 46.

accompanying drawing in which: A soft metal gasket 48, preferably copper, is in- Figure l is an elevational view of a carburetor terposed between the block M and the manifold, and control mechanism therefor; and as the bolts are drawn up tight, the soft Figure 2 is an end elevational view of Figure-l, gasket will be forced into the irregularities of partly in section along the line 2--2 of Figure 1, the surfaces with which it is in contact to form looking in the direction of the arrows; a good heat conducting connection between the 55 of the block M and serves with it thermostat. The block u is preiquantlty o! heat.

In the operation o! the device, hot gases pass- 42 heat the is restarted before it has d a chance to cool down to atmospheric temperature, the thermostat will be above atmospheric temperatureand the mixture will be maintained at more nearly correct richness. By properly proportioning the of the thermothe material from which the The gasket 48, specified as a heat insulation between the thermostat.

tion and convection.

In the modiilcation shown in Figures 4 and 5, somewhat the same type of heat reservoir is4 tions may be made.

I claim:

2. The combination with an internal combustion engine having

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