US1798388A - Carburetor - Google Patents

Description

March 31, 1931. w w s co -r 1,798,388

CARBURETOR Filed Sept. 4. 1929 2 Sheets-Shem l 75 Gave/"Her I J3 9 J7 INVE TOR March 31, 1931.

B. w. WESTCOTT 1,798,388

CARBURETOR Filed Sept. 4, 1929 2 Sheets-Sheet 2 Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE BRAYTON' W. WESTGOTT, F DETROIT, MICHIGAN, ASSIGNOR T0 ZENITH DETROIT GOR- IPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN of the character referred to,

GARBURETOR Application filed September 4, 1929. Serial No. 390,247.

The present invention relates broadlyto the art of carburetion and more particularly to an improved carburetor construction for internal 'combustion engines insuring normal or ordinary operation thereof with maximum fuel economy while enabling the obtaining of maximum power when the engine iis i:called upon to perform an extra heavy u y. p 8 It has heretofore been proposed in the art to which the present invention relates to provide carburetors having normal and auxiliary fuel passages in which the auxiliary fuel passages were controlled by pressure conditions on the engine side of the carburetor throttle. that such constructions are extremely objectionable when used in connection with an automatic governor throttle controlled independently of the hand throttle. It not infrequently happens, with the construction that the driver has the carburetor throttle wide open while the motor is actually being throttled by the governor. In such cases, where the auxiliary fuel passage is controlled by pressure conditions above the throttle, the mixture is enrichened, although the operating conditions of the engine as determined by the governor throttle do not require such an enrichment.

The present invention provides an improved construction in which the proportion of fuel to air is determined'in accordance with the requirements of the engine governor, irrespective of the position of the normal throttle. I

In the accompanying drawings I have shown for purposes of illustration only, certain preferred embodiments of the present invention.

In the drawings Figure 1 is a vertical sectional view through one form of carburetor constructed in accordance with the present invention,

certain of the parts being shown in elevation, and

Figure 2 is a detail view illustrating a fuel control valve of modified construction.

With the ordinary throttle controlled internal combustion engine, the proper mix- I have found, however,

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ture ratio of fuel and gas for purposes of maximum economy is not constant with varying load conditions. As the load or Work being done varies, the quantity of the mixture must be varied, as well as the quality or richness thereof. If a carburetor 'is so adjusted as to give maximum fuel economy over its normal range of operation, it does not enable the engine to develop its maximum power. On the other hand, if the carburetor is set so rich as to insure the development of maximum power by the engine, there is a very appreciable loss of eificiency with respect to fuel consumption throughout the major period of engine operation.

In accordance with the present invention, there is provided a construction by means of which the normal mixture ratio may be automatically enrichened when the load conditions on the engine require such a condition.

In the illustrated embodiment of the invention there is provided a carburetor comprising an air inlet 2 delivering to a mixing chamber 3, within which is positioned a suitable ven- 4. For controlling the flow from the carburetor, there may be provided the usual hand throttle 5.

Cooperating with the mixing chamber 3 and constituting a continuation thereof intermediate the carburetor and the engine which it services, is a chamber 6, within which is positioned a governor controlled throttle 7 of anyv suitable construction. It will be understood that this throttle is of the automatically operated type and therefore has its position determined entirely by the conditions of operation of the motor serviced by the carburetor in connection with which the governor is utilized.

For delivering fuel to the mixing chamber, there may be provided a suitable nozzle system 8, in communication with afuel reservoir 9 of the constant level type, bymeans of a calibrated opening 10 in the metering lug 11, which in turn delivers into a cham er 12. This chamber has leading therefrom a passageway 13 in communication with the nozzle system. 1

. With the construction as thus explained, during normal operation of the engine serviced by the carburetor, fuel for motive purposes will be delivered to the nozzle system entirely through the metering orifice 10, and thus under such accurate control as to give the desired efiiciency of operation.

Extending into the chamber 12 is a valve stem 14, carrying a valve 15, adapted to cooperate with a seat 16 formed in the upper portion of the chamber 12. This valve is herein illustrated as resiliently carried by the valve stem through the medium of a suitable compression spring 17 surrounding such stem and abutting against a suitable removable shoulder 18 on the lower end thereof.

At its upper portion, the stem is enlarged in such manner as to provide in effect one or more piston portions 19 cooperating with the walls of the chamber 12 as a cylinder. The extreme upper end of this chamber is in communication by means of a passageway 20 with-a conduit 21, opening at 22 into the chamber 6 at such a position relative to the governor controlled throttle 7 as to be subject to the pressure conditions in the chamber 6 intermediate the governor throttle and the engine, irrespective of pressure conditions intermediate the-throttles 5 and 7 or in the mixing chamber orair intake below the throttle 5.

It may well happen during operation of a carburetor of the character herein described, thatthe operator intentionally, or by reason of his inability to properly coordinate the mechanical parts of the carburetor with the actual requirements of the engine under particular load conditions, will move the hand operated throttle 5 into its fully open position, as illustrated in Figure 1. At such time, the governor, over whose operation when once set the operator has no control, may position the governor throttle 7 in a partly. open position, as also illustrated in Figure 1. At this time it will be obvious that the load conditions on the engine are not such as to require a mixture richer than normal, since the engine is actually operating only on part open throttle. During such times, the vacuum existing in the chamber 6 above the governor throttle 7 will be transmitted by way of the conduit 21 and the passageway 20 into the upper portion of the chamber 12, whereby the valve stem 14 and its valve 15 will, due to the operation of the piston portions, be held in elevated position, as illustrated in Figure 1. If, however, the load on the engine is increased in such manner that the governor moves the throttle 7 to its wide open position, as illustrated in dotted lines in Figure 1, the absolute pressure conditions existing within the chamber 6 above the governor throttle will more nearly approach the pressure conditions below such throttle. The vacuum will not then be such as to maintain the valve 15 in its elevated position against the action of gravity, and it will dropaway from the seat 16.

At such times, fuel will be free to flow from the constant level chamber through an alternative passage 23 into the chamber 12 and thence by way of passageway 13 into the 'nozzle system 8. This alternative fuel passageway may be of any suitable dimensions such that the flow therethrough will be greater than the metered flow through the metering orifice 10. Thus, when the valve moves to this lower position, in accordance with conditions of operation of the engine and its corresponding requirements, the quantity of fuel delivered to the nozzle system and thence to the mixing chamber Will be increased. While this represents a sacrifice in operating efiiciency, it effects an increase in power, as required for the then existing conditions.

As soon as the load requirements of the engine have decreased to such a point that the governor returns the throttle 7 to its full line position, the higher vacuum conditions above this throttle will be transmitted to the valve mechanism in such manner as to close the alternative fuel system and thus reestablish normal operating conditions through the metering orifice 10.

It will "be apparent from the foregoing that the quality of the fuel mixture delivered by the carburetor is directly responsive to the actual engine requirements, irrespective of whether the position of the hand operated throttle 5, or the position of the mechanically operated throttle 7, controls the amount of explosive mixture required by the motor.

In Figure 2 of the drawings there is illustrated a slightly modified embodiment of the invention with respect to the control valve. In accordance with this embodiment, the fuel reservoir 9"normally delivers fuel to a nozzle system 8 by means of a passageway 25 leading into a chamber 26. This chamber in turn communicates with the nozzle system through a passageway 13'.

During conditions of operation of partly open throttle as determined by the governor, the suction transmitted through the conduit 21 and passageway 20' to the upper portion of the valve stem 14 is such as to maintain this valve stem in its elevated position, as illustrated in Figure 2, whereby the valve 15 will be held in engagement with the seat 16. At such times, fuel Will be compelled to pass from the float chamber through the passageway 25 into the cross channel 27 in the valve stem, and thence by way of the longitudinal channel 28 into the calibrated opening through the metering plug 29. From this opening it will pass by way of the lower part of the chamber 26 into the passageway 13, and thence to the nozzle system.

When the governor throttle is moved to its wide open position, the valve stem 14 will drop, as described before, thereby moving the valve 15' away from its seat 16 and permeans mitting the fuel to flow directly from the float chamber to the nozzle system by way of the passages 25 and 13 connected by the intermediate chamber 26 therebetween.

This construction is advantageous in certain cases where it is desired to provide a single fuel passageway which at times is partially throttled by means of the valve 15, and which at other times is in wide open condition. Such a construction eliminates the necessity of providing a plurality of fuel passageways from the float chamber, as will be apparent.

Ihe present invention provides a carburetor which may be adjusted to satisfactorily meet all normal requirements of the engine serviced thereby with respect to normal power requirements and maximum efliciency, and automatically controlled by the governor in such manner that only during periods of tem, a valve cooperating with one of said passages, and pressure transmitting connections intermediate said valve and said air system at a point inwardly of said innermost control means.

5. In a carburetor, an air system, a fuel system delivering fuel thereto said fuel system including alternative fuel passages, a plurality of control means in series in said air system, governor operated means for actuating one of said control means, a valve cooperating with one of said passages, and pressure transmitting connections intermediate said valve and said air system at a point inwardly of the said innermost control means.

In testimony whereof I have hereunto set my hand.

BRAY'ION W. WES'IGOT'I.

actual requirement, as determined by such governor, are the characteristics of the mixture so modified as to give increased power with a corresponding decrease in fuel efi ciency.

While I have shown and described certain preferred embodiments of my invention, it is to be understood that the scope of my invention is not to be limited thereto, and that changes in the construction and operation may be made without departing from the scope of the following claims or the spirit of the invention.

I claim z.-

1. In a carburetor having an air intake passage and mixing chamber, throttle means cooperating therewith, a governor controlled means inwardly beyond said throttle means, a fuel system for delivering fuel to said mixing chamber, an alternative fuel supply for said system, a valve controlling said alternative fuel supply system, and means operated by the pressure in the intake passage inwardly beyond the governor controlled means for controlling said valve.

2. In a carburetor, an air system including a hand operated throttle, and a governor controlled means inwardly thereof, a fuel system delivering into said air system, and means controlled by pressure conditions in said air system inwardly of said governor controlled means for changing the mixture delivered by said fuel system.

3. In a carburetor, an air system, a'fuel sys-.

tem delivering fuel thereto, a plurality of control means in series in said air system, one of said control means being governor operated and means controlled by the pressure in said air system inwardly of said last mentioned means for modifying the fuel delivery of said fuel system.

' l. In a carburetor, an air system, a fuel sys- 4 tem delivering fuel thereto, said fuel system including alternative fuel passages, a plurality of control means in series in said air svs-

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