US2074353A - Charge forming device - Google Patents

Description

MgrCh 23, 1937. ASELTlNE 2,074,353

CHARGE FORMING DEVICE Filed July 9, 1931 INVENTOR YQZ LS -41! ATTORNEYS Patented Mar. 23, 1937 PATENT OFFICE CHARGE FORIVIING DEVICE Fred E. Aseltinc, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application July 9, 1931, Serial No. 549,644

a 12 Claims. (Cl. 277-4) This invention relates to charge forming devices for internal combustion engines and is disclosed as embodied in a charge forming device having a plurality of primary carburetors adapted 5 to deliver a primary mixture of fuel and air to a plurality of secondary carburetors in which the primary mixture may be mixed with additional air. In fact, the invention is shown herein as embodied in a carburetor of the above type adapted particularly for an eight cylinder engine and having dual outlet passages adapted to cooperate with a manifold having two conduits formed therein, each of which is adapted to register with one of the carburetor outlets when the device is assembled.

The present invention is particularly adapted to a device of the character disclosed, but it will be understoodthat its use is not limited to such a device and the invention is of general application in any form of charge forming device.

It is the object of the present invention to provide a throttle valve or a plurality of throttle valves, the size of which can be adjusted, so that they can be accurately adjusted to fit the outlet 5 passage or passages of the carburetor.

Throttle valves of this character are particularly effective in a charge forming device having dual outlets and adapted for use with an eight cylinder engine having a plurality of separate 3 passages in the manifold, because it is very difficult to maintain the same suction conditions in each of the two manifold passages and throttles of the type shown can be adjusted to compensate for variations in suction conditions and thus 35 obtain similar mixture proportions in the mixtures delivered to the two manifold passages.

The charge forming device disclosed herein is a of substantially the same general construction as that shown in the application of Fred E. Aseltine 40 et al., Serial No. 370,179, filed June 12, 1929, differing therefrom primarily in the fact that there are four primary mixture passages and two secondary air passages, each of the latter being 4 adapted to register with one of two passages in I 45 the manifold which is not shown herein.

Further objects and advantages of the present inventionwill be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodi- 50 ment of one form of the present invention is.

clearly shown. In the drawing: 7

Fig. 1 is a vertical, longitudinal section through a charge forming device in which the present in- .55 vention is embodied.

Fig. 2 is a horizontal section on the line 2-2 of Fig. 1.

Fig. 3 is a fragmentary vertical section on the line 3-3 of Fig. 1.

Fig. 4 is a detail View.

The carburetor unit disclosed herein comprises a main housing 20, having a flange 22 by which it may be attached to a cooperating flange 24 on themanifold in the usual manner. A valve controlled air inlet coupling 26is secured in position in an opening in the top of the main housing in any desirable way. A casting 28, in which the fuel passages are formed which convey fuel from the fuel reservoir to the nozzles, is secured to the bottom of the main housing in any suitable way and a sheet metal fuel bowl 30 is held tight against an annular shoulder 32 on the main housing by a screw 34. Fuel is supplied to the fuel bowl from a main source of supply in the conventional manner and a constant level of fuel is maintained in the bowl 30 by a float, not shown.

A plurality of primary mixture passages 36 are formed in the lower part of the main housing and register with corresponding passages 31 in the manifold when the device is assembled. Communicating with the primary mixture passages through restricted orifices 38 are primary mixing chambers 40, there being four of these chambers in the device disclosed herein. Fuel is supplied to each of these mixing chambers by two fuel jets 42 and 44 which may be designated low and high speed fuel jets respectively. Fuel is conveyed to these fuel jets from the fuel bowl 30 I by fuel conduits in the casting 28, which are not shown herein and which form no part of the present invention, but which may be of substantially the same construction as disclosed in the earlier application above referred to.

A small quantity of air is admitted to the primary mixing chambers through a slot 46 formed in a partition separating these chambers from a main air chamber 48 to which air is admitted through the coupling 26,.and from the atmosphere through holes 50. A super-rich mixture of fuel and air is formed within the primary mixing chambers and flows through the orifices 38 into the primary mixture passages where it is mixed with additional air supplied through the diagonal air passages 52 from the main air chamber to form a mixture of combustible proportions, which is conveyed to the secondary mixing chambers, in which under certain operating conditions, it may be mixed with additional air.

The flow of mixture through the primary mixture passages is controlled by a primary throttle valve 54, which extends across all of the passages and is provided with grooves 56, which register with the passages. This throttle may be operated by means such as shown in the above earlier application, or by other suitable mechanism.

The air admitted to the carburetor through the coupling 26 is controlled by a spring held suction operated air valve 58 of the same construction and controlled in the same way as in the earlier application. This valve admits air directly to the main air chamber 48, from which it flows to the primary mixing chambers and mixture passages in the manner previously described, and also flows to the secondarymixing chambers in the manifold through two secondary air passages 60, best shown in Fig. 2. Each of these secondary air passages is controlled by a manually operable air throttle 62, both of which are mounted on the same shaft 64, journalled in the housing, and by one of two suction operated air valves 66, both of which are secured to a shaft 68 also journalled in the housing, so that both valves 62 and both valves 66 are operated simultaneously. The passages 60 communicate with two passages 19, one of. which is shown in Fig. 1.

The operating mechanism for the valves 62 is not shown herein as it forms no part of the present invention. However, in order that the present invention may be more clearly understood, it may be said herein that the operating connections between the throttle valve and the valves 62 areso constructed that the throttle may make a predetermined movement without any corresponding movement of the valves 62, this movement being such as to permit the vehicle on which the carburetor is used to be operated at a speed .of approximately twenty miles per hour on a level before the valves 62 begin to open. Of course, no movementof the valves 66 can take place until the valves 62 make some opening movement. At speeds higher than that above referred to, air is supplied through the secondary air passages 60 to the secondary mixing chambers in the manifold to be mixed therein with the primary mixture.

The opening movement of the air valve 58 is retarded to some extent by a dash pot comprising a cylinder 12 formed in the casting 28 and a cooperating piston 14 slidable in the cylinder and secured to the lower end of the air valve stem 16. This dash pot effects some retardation of the opening movement of the air valve following any opening movement of the throttle for the purpose of preventing fluttering of the valve and to assist in the formation of a mixture of the desired proportions to properly operate the engine during the acceleration period which immediately follows any opening movement of the throttle.

All of the mechanism described above, with the exception of the provision of four primary mixing chambers and the dual arrangement of secondary air passages cooperating with separate passages in the manifold is of substantially the same construction as that shown in the earlier application above referred to.

As indicated previously, in a carburetor or charge forming device of. this character for an eight cylinder engine in'which a manifold having two separate passages, each of which communicates with four engine cylinders, is provided, it is diflicult to maintain the same suction conditions in the two manifold passages. If unequal suctions are present in thesetwo passages and no compensating means is provided to correct such conditions, unequal suctions' will be maintained at the fuel jets supplying different engine cylinders, resulting in unequal fuel distribution and unsatisfactory engine operation. The novel form of throttle valve disclosed herein was provided primarily to overcome the difficulty described, but as the size of such valve is variable, it may be adjusted to secure a very accurate fit in any passage it is employed to control and, therefore, is useful in any type of carburetor to overcome difficulties due to inaccuracy of construction, warping of the parts, or wear. In the type of device disclosed herein, the two valves 62 may be differently adjusted so as to close the passages 60 to a slightly difierent degree for any given position of the shaft 64, thus permitting slightly different amounts of air to flow through the two passages 60 and in this way, the suction effective on the jets in the different primary mixing chambers can be equalized and substantially uniform fuel distribution to the different'groups of engine cylinders served by the two passages 60 can be effected.

In order to secure these results, each of the valves 62 is formed of two separate disks and 82, which are received in slots 84 in the shaft 64, and are held in position in such slots by machine screws 86, projecting through slots 88 in the disks, whereby the disks may be adjusted relative to said shaft and to each other. Obviously,,by this arrangement, the total area of each valve 62, as well as the degree to which each of these valves closes its associated passage 60 in any given position of the shaft 64 may be varied as desired. This will vary the opening through which air flows in one passage relative to the air opening of the other passage and thus makes possible the equalization of suction above referred to. It is equally obvious that a throttle valve of this construction could be employed in the single outlet passage of a carburetor of conventional type.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a carburetor, a throttle valve comprising a rotatably mounted valve supporting shaft, a slot in said shaft, a plurality of disks received within said slot and adjustable relatively to the shaft, whereby the throttling effect of said valve for any given position of said shaft may be varied.

2. In a carburetor, a throttle valve comprising a rotatably mounted valve supporting shaft,

a slot in said shaft, a plurality of disks received within said slot and adjustable relatively to the shaft, whereby the throttling effect of said'valve for any given position of said shaft may be varied and means for retaining said disks in any adjusted position insaid slot.

3. In a carburetor, a throttle valve comprising a rotatably mounted valve supporting shaft, a

slot in said shaft, a plurality of disks received within said slot and being provided with adjusting slots and retaining screws projecting through said slots for retaining said disks in any adjusted position.

4. In a carburetor having an intakepa s'sage adapted to supply combustible mixture to an'fe'n gine intake port, a throttle valve therein for controlling the flow of fuel mixture through the intake passage, a rotatable shaft for variably positioning the valve as a unit to control the mixture flow and supporting said throttle valve,"s aid valve being formed by a plurality of members tween itself and the wall of the intake passage when in such position and means for retaining the adjustable members in any desired adjusted position on said shaft.

5. In a carburetor having an intake passage adapted to supply combustible mixture to an engine intake port, a throttle valve within said passage comprising a support and a plurality of members adjustable relative to the support and to each other to vary the size of the throttle valve with respect to' the intake passage, means for maintaining said members in any adjusted position on said support and operating means for variably positioning the support to operate the throttle valve, as a unit.

6. In a carburetor having an intake passage adapted to supply combustible mixture to an engine intake port, a throttle valve within said passage, a supporting shaft therefor, said valve comprising a plurality of discs adjustable relative to the support and to each other to vary the size of the throttle valve with respect to the intake passage, operating means for variably positioning the shaft to operate the throttle valve as a unit to variably control the flow of mixture,

and means for retaining the adjustable discs in any desired position.

'7. In a carburetor having an intake passage adapted to supply combustible mixture to an engine intake'port, a throttle valve positioned within said intake passage to control the flow of mixture therethrough, said throttle valve comprising a plurality of discs adjustable relative to each other to regulate the total area of the valve, means for retaining the discs in adjusted position, and means for operating the valve as a unit to regulate flow of fluid through the intake passage.

8. In a carburetor having a plurality of separate intake passages, a throttle valve positioned within each intake passage to control the flow therethrough, a single supporting shaft for said plurality of valves, each of said valves comprising a plurality of members adjustable on the shaft and relative to each other to regulate the area' of said valves, and means for operating said shaft to variably position each of said valves as a unit in its respective intake passage.

9. In a carburetor, a throttle valve therefor comprising a plurality of disks slidably adjustable relative to each other whereby the total area of the valve may be varied for controlling the effect of said valve in closed position, an operating shaft for said valve, means for securing the disks on said shaft in adjusted position and means for operating the shaft to move the valve as a unit.

10. In a carburetor, a throttle valve for controlling flow of a fluid comprising a rotatably mounted valve supporting shaft, a plurality of disks mounted on said shaft and slidably movable relative thereto, whereby the total area of the valve may be adjusted to vary the throttling effect of the valve, means for retaining the disks in any adjusted position, and means for rotating the shaft to move the valve as a unit to variably regulate fluid flow.

11. In a carburetor having an intake passage adapted to supply combustible mixture to an engine intake port, a throttle valve therein formed by a plurality of adjustable members positioned within the intake passage and capable of adjustment relative to each other to so regulate the area of said valve that it fully closes the intake passage when in closed position or permits a flow of mixture between itself and the wall of the intake passage when in such position, means for retaining the adjustable members in any ad justed position and operating means for variably positioning the throttle valve as a unit to variably regulate the flow through the intake passage.

12. In a carburetor having two separate intake passages, a throttle valve positioned within each intake passage to control the flow therethrough, a single supporting shaft for said valves, one of said valves comprising a plurality of members adjustable relative to each other to regulate the area of said valve, and means for operating said shaft to variably position each of said valves as a unit in its respective intake passage.

FRED E. ASEL'I'INE.

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