US2035938A - Charge forming device - Google Patents

Description

arch 31, 1936. s m 2,035,938

CHARGE FORMING DEVICE Filed May 22, 1951 Patented Mar. 31, 1936 UTED STATES PATENT FFICE 2,035,938 CHARGE FORMING DEVICE Fred E. Aseltine, Dayton,

Ohio, assignor, by

ware

Application May 22, 1931, Serial N6. 539,282

11 Claims.

This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this character which comprise a plurality of primary carburetors, each of which delivers a primary mixture of air and fuel to one of a plurality of secondary mixing chambers located adjacent the engineintake ports and in which the primary mixture is mixed with additional air under certain operating conditions.

A device of this character is shownin the copending application of Fred E. Aseltine, et al., Serial No. 288,683, filed June 27, 1928.

It is the object of this invention to provide means to insure a high velocity of flow through the secondary mixing chambers under all operating conditions so that puddling of the fuel in the secondary mixing chambers will be prevented, and which is so constructed that the area of the intake passages will not be sufiicientlyrestricted at any point to materially reduce the engine power. While this invention is more particularly adapted for use with engines of the L-head type; it will be understood that it is also applicable to other types of engines, for by preventing the precipitation of fuel in the secondary mixing,

chambers as above described, it improves the distribution of fuel mixture to the various engine cylinders and by increasing the velocity of flow of the mixture, improves the operation of any type of engine during the acceleration of the engine and other operating conditions. 7

Further objects and advantages of the present invention will be apparent from the following description reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a longitudinal section through a charge forming device constructed in accordance with the present invention.

Fig. 2 and 3 are sections on the lines 2-2 and 33 respectively, of Fig. 4.

Fig. 4 is a longitudinal section through an insert adapted to fit within the outlet branches of the manifold which forms part of the charge forming device.

Fig. 5 is a view similar to modified form of valve.

Thedevice disclosed comprises a main air manifold ll], having three outlet branches, the middle branch l2 being shown herein. Each outlet branch communicates with one of the ports of a multicylinder engine and each is provided with an attaching flange M for securing the manifold Fig. 4, showing a to the engine in the conventional manner, while a flange I6 is provided on the manifold inlet for securing the carburetor unit thereto. Each branchof the manifold is not shown in detail herein as all are alike in construction, one only 5 of such branches being shown for the sake of simplifying the discosure. V e The carburetor unit comprises a main housing l8, having a flange 28 adapted to be secured in any desirable way to theflange 16, while an air 10 inlet coupling 22 is secured in an opening in the housing to admit air thereto. A casting 24, in which the passages for conducting fuel from the fu el bowl to the nozzles are formed, is secured to the bottom wall of the main housing and a sheet 5 metal fuel bowl 26 is held tight against a shoulder 28 on the main housing in any suitable man: ner, Fuel is conducted to the bowl 26 from a main source of supply and a float 30 maintains a substantially constant level in the bowl in the 20 usualway.

Fuel is conducted from the bowl to a plurality of fuel nozzles 32, which project into the primary mixing chambers 34 by means which are fully disclosed in the above mentioned application, but 25 whichhave been omitted herein for the sake of simplifying the disclosure, the structure of the fuel supply passages and the like being entirely immaterial with respect to the present invention. There are three of the nozzles 32 and chambers 30 34, each of the chambers being adapted to communicate with one of three primary mixture passages 36, which passages register with conduits which are adapted to convey the primary mixture to secondary mixing chambers formed in the out- 35 let branches of the manifold as more fully described later. Only one of the conduits referred to is shown herein, namely, that associated with the middle outlet branch of the manifold. This conduit is in the form of a sheet metal tube 38, 40 fixed in position in the manifold anddelivering primary mixture at the point adjacent the bottom of the middle outlet branch of said manifold, as

clearly shown in Fig. 1. v

As indicated in Fig. 1, the primary mizn'ng 45 chambers constitute the enlarged ends of the passages 36 and positioned adiacentthe nozzles and posterior thereto at the posteriorends of the mixing chambers are restrictions 40, these restrictions operating to reduce the velocity of flow past the 50 nozzles to prevent the formation of a substantial velocity head at the nozzles.

The flow of mixture through the primary mixture passages is controlled by a single throttle valve 42 which extends across all of said mixture 55 passages and is provided with grooves 44, which register therewith. The operating mechanism for the throttle is not disclosed herein and is not material to the present invention.

Air is admitted through the coupling 22 and is controlled by a suction operated valve 46, normally held closed by spring 48, received between the valve and the flange 59, projecting from a sleeve 52, slidable on a fixed sleeve 54, which is secured in the housing in any desirable manner and operates as a guide for the valve stem 56. The opening movements of the valve 46 are retarded to insure the correct mixture during the acceleration period by means of a dashpot comprising the cylinder 58, formed in the casting 24, and the piston 60, secured to the end of the valve stem 56. Air passing the valve 46 enters the main air chamber 62, which supplies air to the primary mixing chambers through an opening 64 in the floor of said air chamber and to the secondary mixing chambers in the manifold through a secondary air passage 66, which communicates with the inlet of the manifold ID.

The flow of air through the latter passage is controlled by manual and suction operated valves 68 and Hi respectively, which are secured to shafts I2 and I4 respectively, both of which are journalled in the main housing. The mechanism for operating the valves 68 and 10 is not disclosed herein since this mechanism constitutes no part of the present invention. However, in order to enable a better understanding of the general operation of the device, the operation of these valves will be briefly described and reference may be had to the above mentioned application for the specific disclosure of the operating mechanism. The primary throttle 42 is connected to the valve 68 by a lost motion connection, while the valve 10 is operated entirely by engine suction and begins to operate only after the valve 68 starts to open. The lost motion connection may be varied to cause the valve 68 to begin opening at various engine speeds, but ordinarily is so constructed that this valve starts to open when the engine is running at a speed sufficient to operate the vehicle at substantially 20 to 25 miles per hour on the level. The opening of the Valve 10 is retarded by means not disclosed herein in order to restrict the flow of air temporarily on opening movements of the throttle in order to secure the desired engine operation during the acceleration period.

The primary mixture which is supplied to the secondary mixing chambers formed in the outlet branches of the manifold is mixed with air in these secondary mixing chambers at all speeds above that at which the valve 68 is opened, but at lower speeds, the primary mixture is carried into the cylinders without dilution by additional air which is admitted through the passage 66. At these lower speeds particularly, and when the engine is operating under heavy load with the throttle open to a considerable extent, the velocity of flow through the secondary mixing chambers is so low that fuel tends to collect on the walls of the secondary mixture passages between the outlets of the various primary mixture conduits and the cylinders. The fuel which tends to collect in this manner is picked up irregularly and carried into the engine in rather large drops or particles of varying size so that the supply of fuel to the various cylinders is irregular and uneven. As a result of this irregular supply and uneven distribution of the fuel, the engine runs erratically and it is the primary purpose of this invention to provide means which is effective under all operating conditions to prevent the above described action taking place.

In order to accomplish this purpose, there is provided in each of the outlet branches of the manifold unit comprising a sleeve 9!! adapted to fit tightly within the associated outlet branch and provided with a flange 92 projecting therefrom which, when the device is assembled, is clamped between shoulders 94 and 96 on the manifold and the engine block, respectively. Rotatably journalled in the sleeve 9E3 are two shafts Q8 and E80 to which are secured in any desirable way, butterfly valves I02 and I04, the valve I02 being unbalanced with respect to the shaft 98, while the valve W4 is provided with holes I06 on the lower half of such valve, this construction also unbalancing the valve I94 to some extent, but not as much as is the valve I02. Also if desired, the holes in the valve I04 may be omitted entirely, these holes being provided primarily to permit the passage of the mixture from the conduit 38 and it is obvious that this mixture could flow beheath the valve, since the valve is not as great in area as the area of the passage within the sleeve.

These valves are connected together by a link Hi8 pivotally connected to lugs H and H2 projecting from the valves Hi2 and I04, respectively, the link passing through a slot in the valve IE2. The valves are held in the position shown in Fig. 4 by a spring IE4, surrounding the shaft 68 and having one end extending over a rod I I6 mounted in the sleeve and the other end engaging the face of the valve IE2. As the valves are opened by engine suction, the spring will be tensioned so that on reduction of suction, the spring is effective to move the valves toward closed position.

The operation of this device should be obvious. As the engine is operating at low speed with the valves 68 and I'll closed, the valves I02 and IE4 restrict the area of the passage through the secondary mixing chamber to such an extent that the velocity of flow therethrough is relatively high and any fuel which tends to precipitate out of the mixture and collect on the walls will be carried through the mixing chamber so rapidly by the high velocity of flow that the precipitation as described, is substantially prevented. It is necessary that this restriction be reduced as the throttle and valves and M are opened or the volumetric efficiency of the engine will be materially cut down. Therefore, the valves 32 and I04 are adapted to operate automatically to vary the area of the passage through the secondary mixing chamber in accordance with the variations in engine suction. Since the valve m2 is unbalanced, the blast of air passing through the secondary mixing chamber will move said valve toward open position and the valve I J4 which is movable therewith through the medium of link I08, being more nearly a balanced valve than the valve I02, acts as a brake to prevent rapid fluttering of the valve I925. If the valve 7 I02 were not provided with this means to retard its motion, it would flutter so rapidly because of rapid changes in suction which occur in engine pulsations that the device would soon be worn out. It will be obvious that the size of the holes I06 in valve IE4 may be varied if desired. This device is substantially effective to prevent any accumulation of fuel by puddling at points posterior to the outlet of the mixture conduit 38 with a resultant increase ineiiiciency of engine operation.

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. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches adapted to communicate with said intake ports, fuel supply conduits discharging fuel into such outlet branch and valves in said branches controlling the velocity of flow therethrough past the discharge end of the fuel supply conduit, and means for cushioning the movement of said valves.

2. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches adapted to communicate with said intake ports, fuel supply conduits discharging fuel into such outlet branch and valves in said branches controlling the velocity of flow therethrough past the discharge end of the fuel supply, conduit, and means for retarding the opening and closing movement of said valves.

3. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches adapted to communicate with said intake ports, an unbalanced suction operated valve in each of said outlet branch s and a balanced Valve connected to each of said unbalanced valves, whereby the movements of the latter are retarded.

4. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, Comprising a plurality of outlet branches adapted to communicate with said intake ports, conduits adapted to supply fuel to the manifold branches, a valve in each of said branches adapted to regulate the velocity of flow past the end of the conduit associated therewith, and means for cushioning both the opening and closing movements of the valves.

5. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing chamber for accelerating the flow therethrough, said means comprising a plurality of suction operated valves, one of which is constructed to operate as a brake to retard the opening movements of the other.

6. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing chamber for accelerating the flow therethrough, said means including an unbalanced valve operated by engine suction, and another valve effective to retard the opening movements of the first valve.

'7. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing cham ber for accelerating the flow therethrough, said means including an unbalanced valve operated by engine suction, and another valve connected to the first valve, said last named valve being effective to retard the opening movements of the first valve.

8. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing chamber for accelerating the flow therethrough, said means including two valves unbalanced to different degrees and operable by engine suction.

9. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing chamber for accelerating the flow therethrough, said means including two valves unbalanced to different degrees operable, and means for connecting said valves whereby one valve operates as a brake upon the other.

10. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air to said primary mixture passage, a secondary mixing chamber to which the primary mixture passage is adapted to supply a primary mixture of fuel and air, means in said secondary mixing chamber for accelerating the flow therethrough, said means including a plurality of valves, one of which is located adjacent the outlet of the primary mixture passage to accelerate the flow past said outlet.

11. A charge forming device for internal combustion engines provided with means for forming a primary mixture of fuel and air, means adapted to convey this primary mixture to a plurality of secondary mixing chambers, means in the secondary mixing chambers adapted to accelerate the fiow therethrough, said means comprising a plurality of suction operated valves, one of which is constructed to retard the opening movement of the other.

FRED E. ASELTINE.

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