US2004242A - Carburetor - Google Patents

Description

F-, H. HEITGER CARBURETOR June 11, 1935.

' Filed March :5, 192

2 Sheets-Sheet 1 7 June 11, 1935. ER 2,004,242

CARBURETOR Filed March 3, 1928 2 Sheets-Sheet 2 III Patented June 11, 1935 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

. 8 Claims. ('01. 261-39) This invention relates to carburetors, and particularly to carburetors in which changes in the temperature of the surrounding air detrimentally affects theproportions of fuel and air. Such carburetors 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 automatically adjustable means adapted to adjust itexplosive motors, but such means is also applicable in cases where a device of this character may'be used after the initial starting and warming up, or during the normal running of automotive vehicles.

With reference to initial starting, this requires a variable ratio of fuel to air under difierent temperature conditions; a greater fuel ratio to 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 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. 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 whole; and this being practically the only portion*that 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 suflicient'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 had in the initial starting of a cold motor, or under cold air conditions, and-so that this initial starting fuel feed mayvary or be made to vary when the air temperature varies; and so also that the fuel and air ratio may vary automatically as 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 in connectionwith the accompanying drawings.

Referring to the drawings, a

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 33 of Fig. 1.

Fig. 4 is an enlarged vertical sectional view of a detail, taken on line 44 of Fig. 3.

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

Fig. 6 is a sectional view of a detail, taken on line 6-6 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 88 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 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 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. 0

, The choke valve of the present invention is 3 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- 35 ent 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-5a. 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.

The ends of the shaft are supported in bearings formed 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 clamped 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 I formed on a boss I projecting from the intake.

for instance impart a 180 degree travel to the gear sufiicient to give a rich starting mixture.

A gear segment I 0 is mounted on the case by means of a screw I0 which passes through an areshaped slot H1 in the segment. This construction permits an initial adjustment of the spring 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 l0 meshes with a larger segment III which is integral with a control lever l2. Due to the difierence in the sizes of the toothed segments l0 .and II, the large gear with a given travel multiplies the movement of the small one, and thus causes multiplication also of the movement of the coil or spring 8. degrees travel of l2 may,

l0, etc. The spring 8 is so arranged that operation of the lever l2 in the direction of the arrow, tends to open the valve, and at its limit of travel (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 reference to Fig. 2. Referring to the large gear i I, in that figure, the part I I of this gear is what may be called a double tooth and this prevent-s travel or acts as a stop when engaging a complementary part II) of the small gear. Likewise, at the other extreme of travel (shown engaged), are similar stops I0 and H In this figure, the lever l2, as in Fig. 1, is in position to choke or close valve d tight; closing it first and then putting added tension on the spring, which, by the way, is calibrated 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 6 has only a 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 ill, by its operation and increasing drive 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 revolutions per minute, and the consequent vacuum obtained is Then, if the temperature of the air is colder, that alone tends to wind spring It! further, so when the manual means (connected to l2 and described later) is applied, the valve closes tighter than in warm 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 lever l2 in warm up position (b) instead. of full choked position (0) for cold weather starting.

The lever I2 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 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 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 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 It remains in intermediate position (b).

For the purpose of manipulating the lever l2,

the handle, under the influence of the spring lGc engages the lower edge of the aperture Hid.

In the warm up position of the handle, the lever I2 is latched in position by the notch l6 and spring I60, 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 lfl -l l abut against each other, and the other extreme can be felt when the stops 1 -4 l 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 easing 5 is retained in position by the segment II which overhangs the latter, and this gear is pivotally mounted on a screw l3 which extends into a boss 88. A wire spring or the like [4 is wound around this boss, and one of its ends bears against the lever i2, and the other end against the boss I; this spring acting to urge the lever to cause the valve to open.

As shown in Fig. 3, I preferably adjustably connect the rod it to the lever I2, and this is accomplished by extending the rod through an aperture in a pin carried by the lever, and clamping the rod by a screw H which extends into the pin.

Referring again to the operation, in the intermediate position (b) of the lever 52, the valve 4 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 (1)), at say 40 to 50 miles per hour; less for less speed.

Then, as the motor warms up until the temperthe valve with the lever at (1)) 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.

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 i2 is in 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 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 maytend to unwind more, tending to open the valve beyond its full 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 restrictions.

Referring to the movement multiplying means, it will be noted that the common limit of travel of lever I2 is from about 90 to 100, and by using a 2-1 gear ratio or the like, the travel bf case, 6

or end ofthermo spring may be made to travel twice this, or 180 to 200. For example, a

90 travel, giving case 6 a 180 travel, valve closafter the valve is in closed position, and as the weather grows colder, the valve will have more 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 travel to open it wide. We have, however, to do it in,a surplus of 10. However, by this time, owing to increased temperature, (from warming up), the spring would 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 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 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 inclusive, may be preferred. In this form of the invention, the movement multiplying means is eliminated, and the lever l2a is fixed directly to the side of the casing 6a. I may also modify this form of the invention by arranging a recess la in the boss 1b, and provide the casing with an annular flange 10 which rotates in the recess. The casing may be secured in position by an annular retaining ring Id which overlaps the flange and is fastened in place by suitable fastening means, such as screws 1e.

The outer end of the thermometal spring 8a in this modification, may beadjustably connected to the periphery of the casing, and for this purpose, the casing has a slot 8b to receive a screw 80 which passes through a hole in the spring and engages a nut 8d. When the screw is loosened, it maybe 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 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 February 20, 1928.

In the present application, Ihave 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 changes may be made in the details disclosed without departing from the spirit of the invention as expressed in the following claims.

What I claim and desire to secure by Letters Patent is:

1. In a carburetor, an air intake, a valve arranged in the intake and so mounted as to open by suction, means comprising a thermostatic spring element adapted to oppose the opening of 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 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 interposed between the spring elementand 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 thermostatic 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 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 enclosing 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.

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 opening 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 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 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 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 arranged 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 manually 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 means and said valve in all positions of said valve.

FRANK H. HEITGER.

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