Carburetor

June 11, 1935. f. h. heitger 2,004,242

CARBURETOR Filed March 3, 1928 2 Sheets-Sheet 1

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June 11, 1935.

F. H. HEITGER

2,004,242

CARBURETOR

Filed March 3, 1928

Sheets-Sheet 2

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Patented June 11, 1935

2,004,242

UNITED STATES PATENT OFFICE

2,004,242

CARBURETOR

Frank H. Heitger, Flint, Mich.; Mattie G. Heitger, Flint, Mich., administratrix of said Frank H. Heitger, deceased, assignor to Bendix Products Corporation, South Bend, Ind., a corporation of Indiana

Application March 3, 1928, Serial No. 258,741

Claims. (Cl. 261—39)

This invention relates to carburetors, and particularly to carburetors in which changes in the temperature of the surrounding air detrimentally affects the proportions of fuel and air. Such car5 buretors are used on automotive vehicles, such as pleasure, commercial and tractor vehicles exposed to atmospheric changes.

The primary object of the invention is to provide such a carburetor with manually and auto10 matically adjustable means adapted to adjust itself in the initial starting and warming up pf explosive motors, but such means is also applicable in cases where a device of this character may be used after the initial starting and warm15 ing up, or during the normal running of automotive vehicles.

With reference to initial starting, this requires a variable ratio of fuel to air under different temperature conditions; a greater fuel ratio to 20 air being required as the weather or temperature of the surrounding air lowers. When the motor is very cold, it requires more of the liquid content of the mixture to obtain a firing or combustible mixture, than would be required after the motor 25 is in a normal running condition or fully warmed up. After the motor is initially started, the ratio of fuel to air can be decreased, and when the motor assumes normal operation, the liquid content may be reduced to an approximate minimum, 30 The fuels generally used at the present time, not being so volatile as in former, years, it requires more of the liquid content under cold weather conditions, due to the fact that the volatile or lightest portion is only a small per cent of the 35 whole; and this being practically the only portionthat is utilized in starting in cold weather. It will, therefore, be appreciated that it is necessary to feed a Considerable amount more of fuel than normal during starting, in order to obtain 40 sufficient of the volatile portion to form an explosive mixture with the cold air admitted to the carburetor.

- It is the purpose of the present invention to provide means whereby this rich fuel feed may be 45 had in the initial starting of a cold motor, dr under cold air conditions, and. so that this initial starting fuel feed may vary or be made to vary when the air temperature varies; and so also that the fuel and air ratio may vary automatically as 50 the motor warms up, and thus automatically feed more air to fuel, or less fuel, as the motor gets warmer, or the air surrounding the carburetor gets warmer.

The invention will now be described in detail 55 in connection with the accompanying drawings.

Referring to the drawings,

Fig. 1 is an elevation of a carburetor partly in vertical section.

Fig. 2 is an elevation of the intake of the carburetor, viewed from the opposite side. 5

Fig. 3 is a transverse vertical sectional view of the intake, taken on line 3—3 of Fig. 1.

Fig. 4 is an enlarged vertical sectional view of a detail, taken on line 4—4 of Fig. 3.

Fig. 5 is a longitudinal sectional view of the ιθ choke valve and its shaft.

Fig. 6 is a sectional view of a detail, taken on line 6—G of Fig. 2.

Fig. 7 is a view similar to Fig. 1, but showing a modification. 15

Fig. 8 is a transverse sectional view taken on line 8—8 of Fig. 7.

Fig. 9 is a sectional view of a detail of the structure shown in Figs. 7 and 8.

Fig. 10 is a vertical sectional view of a detail gg of the modified form of the invention.

In the embodiment of the invention illustrated in Figs. 1 to 6 inclusive, A designates the carburetor generally which may be of the plain tube or Venturi type, provided with the usual air inlet gg B, and the float chamber C.

I designates the usual throttle valve lever, and 2 a screw for making the usual fuel adjustment for idling or the lowest speed, which fuel is fed posterior of the throttle valve. _so _ The choke valve of the present invention is indicated at 4, and it is used for varying the ratio of the fuel and air mixture, whether for the initial starting or warming up period, or normal running. 5 is the valve shaft which, in the pres- ₃₅ent case, is of cylindrical form, and provided with a longitudinally disposed slot to receive the valve, the latter being secured in position by any suitable means, such as screws 5α. The axis of the shaft is arranged below the axis of the intake, so that the portion of the valve above the shaft will be of greater area than the portion below the same. It will be noted that the slot and screws permit the valve to be inserted or removed through the open end of the intake. 45

The ends of the shaft are supported in bearings ⁴formed in the intake, and one of its ends projects beyond one side of the intake, and is connected to a flat thermometal spring 8 which is formed similar to a clock spring, and, has its inner end ₆₀clamped in the slot of the shaft. A case or drum 6 encloses the spring, and is fastened to the outer end of the latter, and this case is rotatably mounted in an annular flange 7 formed on a boss 7' projecting from the intake. 55

2,004,242

A gear segment 10 is mounted on the case by means of a screw i 0³ which passes through an arcshaped slot IO⁴ in the segment. This construction permits an initial adjustment of the spring 6 to be made while assembling the device, and the adjustment of course will accord with the temperature at the time when the adjustment is made.

Gear 10 meshes with a larger segment I II which 10 is integral with a control lever 12. Due to the difference in the sizes of the toothed segments 10 and 11, the large gear with a given travel multiplies the movement of the small one, and thus causes multiplication also of the movement of 15 the coil or spring 8. 90 degrees travel of 12 may, for instance impart a 180 degree travel to the gear 10, etc. The spring 8 is so arranged that operation of the lever 12 in the direction of the arrow, tends to open the valve, and at its limit of travel 20 (.a), shown by dotted lines, the valve will be practically wide open at a normal air temperature around the motor when the latter is enclosed by the usual hood.

The operation may best be explained by refer25 ence to Fig. 2. Referring to the large gear II, in that figure, the part 11' of this gear is what may be called a “double tooth” and this prevents travel or acts as a stop when engaging a complementary part 10' of the small gear. Likewise, at the other 30 extreme of travel (shown engaged), are similar stops IO² and 11². In this figure, the lever 12, as in Fig. 1, is in position to choke or close valve 4 tight; closing it first and then putting added tension on the spring, which, by the way, is cali35 brated or selected of the proper width, thickness and number of coils to practically effect the desired results. This spring need not be as heavy as would be required for some types of valves, owing to the fact that the valve i has only a 40 small area effective for suction, although the valve is of relatively large diameter. Due to the construction and arrangement of the present valve, the spring is relatively light.

Lever 12, by its operation and increasing drive 45 ratio, is such, however, that the spring can be wound up enough to prevent the valve from opening on an initial start of the motor, as the motor turns somewhat slowly, about 100 revolutions per minute, and the consequent vacuum obtained is 50 sufficient to give a rich starting mixture. Then, if the temperature of the air is colder, that alone tends to wind spring 10 further, so when the manual means (connected to 12 and described later) is applied, the valve closes tighter than in warm 55 weather. I may state here, I have found that in warm weather, the starting mixture for a cold motor can be had, even though the valve opens, or pulsates slightly open or close. In fact under such conditions, the motor will start with the 60 lever 12 in warm up position (b) instead of full choked position (c) for cold weather starting.

The lever 12 is shown at (c) or in its position for starting, as an example, say at temperatures between 32“ to 40° F. When the lever is put in 65 this position, it not alone closes the valve, but winds the spring a definite amount at the existing temperature. On the other hand, if the temperature is, say, zero F„ the valve is held closed tighter, due to the tendency of the spring to wind 70 further at lower temperatures. When the lever is put in “warm up” or intermediate position (b) at zero weather, the valve will open less by suction than at 32“ or 40°, and therefore, a somewhat richer fuel content of mixture will be had, which 75 is essential. Then, as the surrounding air rises in temperature, during the warming up period (owing to the motor heating the air), the tension of spring 8 becomes less, even though the manual means 12 remains in intermediate position (b).

For the purpose of manipulating the lever 12, 5 I have provided a control rod 16 pivotally connected at its lower end 15, to 12. The upper end of the rod - is provided with a handle 16α having a longitudinal slot 16b in which a wire spring 16c operates. The handle slides in an aperture I6d 10 arranged in the dash or instrument board 16e. When the handle is half way in, a notch 16/ on the handle, under the influence of the spring 16c engages the lower edge of the aperture 16d.

In the “warm up” position of the handle, the 15 lever 12 is latched in position by the notch 16/ and spring 16c, so the driver can “feel” when it is in this position. The full off or wide open position is felt by the operator when the stops IO¹— 11¹abut against each other, and the other extreme 20 can be felt when the stops IO²—11² on the gears come into engagement. Of course, any other suitable means may be substituted to accomplish the same purpose.

It may be mentioned at this point that the cas- 25 ing S is retained in position by the segment 11 which overhangs the latter, and this gear is pivotally mounted on a screw 13 which extends into a boss 18. A wire spring or the like 14 is wound around this boss, and one of its ends bears against .30 the lever 12, and the other end against the boss Ί'; this spring acting to urge the lever to cause the valve to open.

As shown in Fig. 3,1 preferably adjustably connect the rod 16 to the lever 12, and this is accom- 35 plished by extending the rod through an aperture in a pin carried by the lever, and clamping the rod by a screw Π which extends into the pin.

Referring again to the operation, in the intermediate position (b) of the lever 12, the valve 4 49 should just close, say at a 60“ temperature, and during the warm up period, its maximum opening by suction would be at about the point (b'), at say 40 to 50 miles per hour; less for less speed. Then, as the motor warms up until the temperature becomes, say 100“ within the engine hood, the valve with the lever at (b) would have less resistance, and open wider under the same speed conditions, and consequently, the ratio of air to liquid will become greater, which is essential. 59

If, when starting the “warm up” period, the air temperature is, say 32“ instead of 70“, the spring 8 will have more tension on it than at 70°, whereby a somewhat richer mixture will be had which is desirable. When the lever 12 is in 55 the position (a), the valve 8 is in its full wide open position, and abutting against stop 50 at normal operating temperature. This may vary some as the outside temperature varies. The temperature under the hood varies also, but the device 99 is so designed and calibrated that this variation in temperature does not materially affect the mixture at wide open position (a). At some temperatures, the spring may tend to unwind more, tending to open the valve beyond its full 95 open position, or at some lower temperature, may tend to close the valve somewhat from a wide open position; a limited degree of which would offer no objection, as the intake bore is usually designed with a surplus area, to be sure of no 70 restrictions.

Referring to the movement multiplying means, it will be noted that the common limit of travel of lever 12 is from about 90 to 100°, and by using a 2-1 gear ratio or the like, the travel of case. 6 75 ,242 3 the valve by suction, manual means cooperating with said thermostatic spring element to operate the valve, and means to latch said manual means in adjusted position.

2. In a carburetor, an air intake, a pivotally 5 mounted valve arranged in the intake opened by suction, a thermo spring element adapted to oppose the opening by suction, manually operated means for varying the tension of said thermo spring element, and movement multiplying means 10 interposed between the spring element’and said manually operated means.

3. In a carburetor, an air Intake, a valve arranged in the intake and so mounted as to open under certain conditions due to suction, a thermo- 15 static spring element opposing the opening of the valve by suction, manual means controlled from a remote point for varying the tension of said spring element, and movement multiplying mechanism interposed between the manual means 20 and said spring element.

4. In a carburetor, an air intake, a valve arranged in the intake and adapted to open under suction influence, a yielding element opposing the opening of the valve by suction, a case en- 25 closing the yielding element and in operative engagement therewith, and means to rotatably move said case for increasing the opposition of the yielding element to the opening movement of the valve. ³⁰

5. In a carburetor, an air intake, a valve arranged in the intake and adapted to open under suction influence in the intake, a shaft on which said valve is mounted, a resilient thermostatic element connected to the shaft and opposing the ³⁵opening of the valve by suction, an oscillating member connected to one end of said thermostatic element, a second oscillating member having a driving connection with the first mentioned oscillating member, and control means operatively 40 connected to said last mentioned oscillating member, and adapted to be actuated by the operator for varying the tension of the element.

6. In a carburetor, an air intake, a pivotally mounted shaft extending across the intake, a 45 choke valve mounted on the shaft within the intake, a thermometal coiled spring having one of its ends connected to the shaft, a casing for the spring rotatably mounted on the intake and connected to the other end of the spring, and a 50 lever for actuating said casing.

7. In a carburetor as claimed in claim 6, means operatively connected to the lever for latching the same in an intermediate position.

8. In a carburetor, an air intake, a valve ar- 55 ranged in the air intake and mounted to open by suction, a coiled thermostatic spring element having a connection with said valve for normally holding said valve in closed position, manually operated means and means connecting said ⁶⁰manually operated means to said thermostatic spring element for adjusting the tension of said thermostatic spring element and for opening said valve, said last mentioned means forming a yielding connection between said manually controlled 65 means and said valve in all positions of said valve.

FRANK H. HEITGER.

2,004 or end of thermo spring may be made to travel twice this, or 180° to 200°. For example, a 90° travel, giving case 6 a 180° travel, valve closing 10° from vertical, in intermediate position, 5 would be, say half open, or 40° travel from onehalf open to just closed position (travel by suction). Then we have 90° to tension spring 8 after the valve is in closed position, and as the weather grows colder, the valve will have more 10 pressure on it, due to the extra tension of spring 8. Likewise, with the valve just closed, and the lever at (b), it would require 80° travel to open it wide. We have, however, 90° to do it in, a surplus of 10°. However, by this time, owing to 15 increased temperature, (from warming up), the spring w'ould unwind to some extent tending to allow the valve to open more, so that when the lever is put in normal running position, the spring will hold the valve wide open under some reverse 20 tension, due to the surplus 10° of travel, plus the increased opening tension of spring 8, brought aboutby increased temperature at the end of the warming up period.

The embodiment of the invention illustrated in 25 Figs. 1 to 6 inclusive, is of special advantage, in places where the carburetor is subjected to wide variations in temperature, but in locations where the temperatures does not vary to any great degree, the structure illustrated in Figs. 7 to 10 30 inclusive, may be preferred. In this form of the invention, the movement multiplying means is eliminated, and the lever 12α is fixed directly to the side of the casing 6α. I may also modify this form of the invention by arranging a recess 7 α 35 in the boss 7b, and provide the casing with an annular flange 7 c which rotates in the recess. The casing may be secured in position by an annular retaining ring 7d which overlaps the flange and is fastened in place by suitable fastening 40 means, such as screws 7e.

The outer end of the thermometal spring 8α in this modification, may be adjustably connected to the periphery of the casing, and for this purpose, the casing has a slot 8b to receive a screw 45 8c which passes through a hole in the spring and engages a nut 8d. When the screw is loosened, it may be shifted along the slot 8b, and it will carry the end of the spring along, and after it has been moved to the desired point, it may be tightened 50 to fix the parts together.

Instead of using the specific movement multiplying means disclosed herein, I may employ mechanism of the character shown and described in my application H, Serial No. 255,821, filed 55 February 20, 1928.

In the present application, I have disclosed preferred embodiments of my invention in such manner that they may be readily understood by those skilled in the art, but it is obvious that 60 changes may be made in the details disclosed without departing from the spirit of the invention as expressed in the following claims.