US1902603A - Automatic priming device - Google Patents

Description

w. wlLsoN AUTOMATIC PRIMING` DEVICE March 2l, 1933.

Filed Aug. 29, 1927 mill/lll Patented Mar. 21, 1933 AUNITED STATES PATENT OFFICE WESLEY WILSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT AND MESNE ASSIGN- MENTS, T0 BENDIX AVIATION CORPORATION, OF SOUTH BEND, INDIANA, A COR- PORATION OF DELAWARE AUTOMATIC PRIMING DEVICE Application md August 29,1927. serial No. 216,171.

My'invention relates to improvements in priming devices.

One of the objects of my invention is to automatically enrichen the normal carbureted fuel mixture supplied internal combustion engines to the proper degree for causing the engine to start without dilficulty and thereafter to a lesser degree until the engine temperature is such that it will operate properly on the normal fuel mixture.

Another object is to attain the preceding object by a simple and efficient means.

i Further objects will appear from the description and claims. V

In the drawing, in which an embodiment of my invention is shown,

Figure 1 is a partial vertical sectional view showing my invention combined and built in a carburetor;

Fig. 2 is a partial sectional view taken as indicated by line 2 of Fig. l.

Corresponding numerals in the various views denote the same parts.

Referring to the drawing, the reference numeral indicates the direction of the iow of the carbureted fuel mixture thru the mixwhere it is kept at a constant level by float 11. When the throttle valve 6 is open and the carburetor is in operation', the How of air thru mixing chamber 34 .is suflicient to suck fuel up thru nozzle 4 from oat chamber 10, Where it is atomized and mixed with the air passing thru venturi 3. A portion of the walls of mixing chamber 34 is projected out to form the cover 41 of Chambers 10, 9, 24, and 25. When the throttle valve 6 is closed the internal combustion enginecan operate only at its slowest or idling speed.. The fuel required to keep the engine idling passes thru mixing duct 5 to the intake manifold 36. As the mixing duct5 will admit onl a small volume of air, there will not be su cient suction produced on nozzle 4 to draw fuel from chamber 10, However the suction produced in mixing duct 5 causes fuel to be drawn from chamber 10 thru fuel passage 8 into mixing 'which may be varied in type, design and construction.

When the internal combustion engine has not been operating for some time and has cooled down to the temperature ofthe surrounding atmosphere, difficulty will be encountered, especially in cold weather, in starting, and after startin the engine will not operate properly untll it has become quite warm. The object of my invention is to overcome this dili-culty, which I have done in the following manner.

Chamber 9 is partitioned oil' from float chamber 10 by wall 17. Wick 14 has one end project into the fuel in chamber 10 while the other end projects to the bottom of chamber 9. The fuel levelin chamber 10 is at a level with line 2 of Fig. 1 and is thus at a substantially higher level than the end of wick 14 which is-in the bottom of chamber 9, and therefor, due to the physical action of capillary attraction and gravitation, liquid fuel in chamber 10 will flow thru wick 14 into chamber 9. The rate of flow thru wick 14 will depend upon the height above the fuel level in chamber 10 that the fuel must be drawn by the action of capillary attraction, by the distance wick 14 projects down into and upon the character of the wick itself.

A U shaped metal casing 20, has one end v projecting thru cover 41 into chamber 9 and the other end projecting thru cover 41 into chamber 10, so as to form a housing for w1ck 14 as it passes from one of said chambers to the other said chamber. A thermostatic Vstrip 27 has one end riveted at 37 tov casing 20, while the other end bears down on wick 14 so as to partially compress it in varying degrees depending upon the temperature.

Adjusting screw 26 provides a means for varying the operation of thermostatic element 27. Due to the action of thermostatic strip 27 the rate of flow of fuel thru Wick 14 will vary as the temperature varies. A small hole 40 in casing 20 acts to prevent any siphonic action.

Wall 23 forms a partition between chambers 9 and 24. Suitable messages (not shown in the drawing) located in cover 4 1 provide atmospheric communication for chambers 9, 10 and 24, so as to keep said chambers at atmospheric pressure. A small passage 22 is 1ocated in and near the bottom of wall 23 and furnishes'communication between chambers 9 and 24.v Chamber 25 is within chamber 24 and is cylindrical. The top of chamber 25 is sealed tight with the exception of a small passage 27 which provides communication with'mixing chamber 34 at the entrance of mixing duct 5. The bottom edge of chamber 25 is finished off flat and smooth to form a seat for disc 28 which acts as a valve. )Vhcn disc 28 is away from the bottom edge of chamber 25 it rests on four small lugs 39 (two of which are shown in Fig. 1) that project about l of an inch up from of chamber 24. These lugs hold disc 28A about 15 of an inch from the bottom edge of chamber 25, in which position it is shown in Fig. 1 When disc 28 is away from .the bottom edge of chamber 25 the communication between chambers 24 and 25 is very large. The wall 23 of chamber 24 is thickened at two points 42 so as to act as a guide for disc 28. The wall of chamber 25 is thickened at one side and former is small and extends from the lower the latter is much larger and extends from the lower portion of chamber 24 to mixing duct 5 and has a needle valve 33 for varying the size of passage. When the internal combustion engine is not operating a portion of the fuel flowing into chamber 9 from chamberI 10 by means of wick 14, will flow into chambers 24 and 25 by means of passage 22 and the kpassage around disc 28 respectively. Thus when the carbureter is not operating the liquid fuel in chambers 9, 24 and 25 will continue to rise until it is at the same level as the Afuel in chamber 10. The How of fuel into chambers 9, 24 and 25 is very slow, varying from five to twenty-five drops a minute, depending upon weather conditions and upon the size and type of internal combustion engine connected thereto. It should also be noted that the rate of fuel flow thru wick 14 will vary in equal time intervals as the level of fuel in chamber 9 rises. an advantage as it is the same as the variation in the rate that the internal combustion engine cools to the temperature of the surrounding atmosphere after it has stopped operatmg.

If the internal combustion engine connected to the intake manifold 36 has been-inoperative for a length of time sufficient for it to have cooled to approximately the temperature of the surrounding atmosphere, cham- This variation is bers 9, 24 and 25 will have become filled with liquid fuel to the same level as the fuel in chamber 10. To start the engine under these y conditions the throttle valve 6 is first closed so that the fuel mixture is obliged to flow thru mixing duct 5. The engine is then turned over by a starter, by handor any other desired means, whereupon a partial vacuum is produced in intake manifold 36, which in turn produces a partial vacuum in mixing duct 5, which in turn causes fuel to be forced thru passage 31 from chamber 24 into mixing duct 5 at 32 by means of atmospheric pressure. Atmospheric pressure will also force fuel from chamber 10 thru passage 8 into mixing duct 5 at 7. The suction or partial vacuum in manifold 36 will also cause air to enter mixing duct 5 from chamber 34 where it will strike the liquid fuel issuing in jets at 7 and 32, and both atomize and vaporize it. At the same time the partial vacuum at the mouth of mixing duct 5, acting thru passage 27 produces a partial vacuum above the surface of the liquid fuel in chamber 25, which in turn causes the atmospheric pressure in chamber 24 (acting thru the liquid fuel) to force valve disc 28 to rise and seat on the bottom surface of chamber 25. lthereby closing the communication between chambers 24 and 25. As passage 29 enters at 30 near the middle of mixing duct 5, while passage 27 enters at the mouth of mixing duct 5, there will be a greater partial vacuum produced in passage 29 than that producedin passage 27, and is due to the friction and eddy currents along the walls of mixing duct 5. Due to this difference in vacuum, fuel will be drawn or forced thru passage 29 from chamber 24 into mixing duct 5 at 30v where it will be atomized and vaporized in a manner similar to the fuel enteringat 7 and 32. As passage 29 is small and the difference in partial vacuum between passage 27 and 29 is not great, the amount of fuel flowing thru passage 29 will be small, so that chamber 25 will empty very slowly when the engine is running.

If for any reason the en'gine should cease to operate very soon after it has emptied chamber 24 of Yits fuel, great diiiiculty would be encountered in immediately restarting, if it were not that the partial vacuum above the surface of the fuel in chamber 25 would immediately be relieved (when the engine stops) by the air at atmospheric pressure flowing into chamber 34, thru passage 27 into chamber 25, which in turn causes ydisc 28 to fall to the bottom of chamber 2,4 thereby allowing the fuel in chamber'25 to flow into CTI Vwill be encountered in immediately restarting the engine.

Needle valve 33 is so adjusted that the combined fuel entering mixing duct 5 at 7, 30 and 32 will be sufficient to produce a mixture with the air that will .cause the engine to operate properly at the time of starting, but` as chamber 24 is small this mixture will only be supplied for a short time so as to avoid the danger of flooding the engine. However, after chamber 24 is emptied, fuel will continue to flow thru passage 22 to chamber 24. As chambers 9 and 24 are both open to the atmosphere and passage 22 is small, the amount of fuel flowing into chamber 24 lwill be small and unaffected by the engine speed. As passage 31 will draw the fuel from chamber 24 as fast as it flows in, it is obvious that the greatest tendency toward enrichening the fuelmixture will be produced when the engine is running at its slowest speed.

After starting the engine the throttle valve 6 may be partially opened so as to speed itup. With-the throttle valve 6 in this position enou h suction is produced in venturi 3 to cause gliel to be forced from chamber 10 thru nozzle 4, and from chamber 9' thru nozzles 19 and 21, into venturi 3 by means of atmospheric pressure. As stated before,

v the rate of flow thru nozzle 4 is suc-l1 as to produce an elicient fuel mixture when the engine is running at its normal operating temperature and chambers 9, 24 and 25 are empty. The rate of fuel flow thru nozzle 19 is the same as that of nozzle 21, and their combined flow plus the flow thru passage 22 is such as to make the engine operate properly before it has heated to its normal operating temperature. As stated before the amount of fuel flowing thru wick 14 is very small, and therefore the fuel level in chamber 9 will fall quite fast when the engine is operating. As the level of fuel in chamber 9 falls, the rateof How thru passage 22 will decrease in direct proportion. There will also be a slight reduction in the flow thru nozzles 19 and 21. However, as the engine will heatl up as the fuel level in chamber 9 falls', there would still be a tendency to excessively enrichen the fuel mixture if nozzles 19 and 21 were both allowed to supply fuel until chamber 9 had become practically empty. By having nozzle 21 extend only about half way to the bottom of chamber 9 this tendency is overcome, as that nozzle becomes inoperative when the fuel level drops below its entrance. Nozzle 19 will continue to sup ly fuel tothe mixing chamber 34 until chamber 9 is nearly empty, the remaining fuel flowing thru passage 22. The .internal combustion engine should by thistimebeheated sufliciently to operate properly on the normal carbureted fuel mixture. Also at this time (when chamber 9 has just become empty) chamber 25 will still have a considerable supply of fuel and should not become empty until the engine has become quite hot. i

If the engine should be restarted at a time when chambers 9, 24 and 25 have become only partially filled with fuel, no difficulty will be encountered in restarting, inasmuch as the amount that the internal combustion engine will have cooled will be proportional to the amount that chambers 9, 24 and 25 .will have filled with fuel.

Thus one of the fundamental dilferences between my invention and other priming devices employing storage chambers, is the rate at which the llquid fuel is supplied tothe storage chambers. By supplying the fuel at a very slow rate I am able to employ large storage chambers and also a large passage 'before it has had time to cool. For example it will take much greater than five minutes of time for the chambers 9, 24 and 25 to become filled with fuel when the engine is not operating, while other devices fill in a fraction of this time.

Needle valve 33 is shown on the drawing as l installation of the priming device needlevalve 33 should be of such length and so arranged that it can be adjusted from the proximity of the throttle lever. Thus if the priming device is installed on the engine of an automobile vehicle, needle valve 33 should be so arranged that it can -be operated from the dashboard or steering post.

It should be noted that to obtain the maximum elliciency from the device as described, the size of chambers 9, 24 and 25, and the rate of fuel flow thru wick 14, will all vary with different sizes and types of engines.

Also it should be noted that for clarity on the drawing no means are shown whereby passages 5, 19, 21, 22, 27, and 29 can be individually adjusted as to size, although such means are desirable under certain conditions.

It should further be noted that while no means is shown on the drawing for choking the carburetor, such a means Willbe desirable although it should very seldom have to be used.

1t should further be noted that in Fig. 1 of the attached drawing passage 8 is shown crossed by passages 19, 21 and 27, and it must be understood that there isno communication A embodiments of my .invent-ion, it is to be vunderstood that it is capable of many modifications. Changes therefor in the construction and arrangement may be made without departing from'the spirit and scope of this invent-ion as4 defined by the following` claims.

I claim:

1. The combination with an internal combustion engine, carburetor and throttle, of a means for automatically supplying additional fuel to the` fuel mixture of said cai'- buretorA whenI the engine is being started, the total quantity of said additional fuel to vary as the time interval between said starting and the last stopping of theengine previous to said starting varies, and a thermostatic means for controlling the action of -said automatic means of supplying additional fuel.

2. A carburetor pr'ovided'with a starting reservoir in which liquid fuel slowly collects when the engine ceases to operate, a means thru which fuel is drawn from said starting reservoir when the engine is operating, a second reservoir, a means for supplying fuel to said starting and said second. reservoirs when the engine is not operating, a communicating means between said starting reservoir and said second reservoir, and a means for preventing fuel in said second reservoir, from flowing thru said communicating means into said starting reservoir when the engine is operating.

3. In combination with a carburetor, a means operated by capillary attraction and gravity for causing liquid fuel to flow from a constant level fuel chamber to a second chamber, and a thermostatic means for controlling the action of said'gravity'and capillary operated means. y

4. In combination with an internal combustion engine, ay carburetor provided with a constant level fuel chamber, a plurality'of additional chambers, meansoperated by capillary attraction and gravitation for causing fuel to flow from said constant level fuel chamber to said additional chambers when the engine is lot operating, a means thru which fuel is drawn from said additional chambers when the engine is operating, and a thermostatic means for controlling the action of saidl gravity operated means.

5. The combination With a fuel intake of an internal combustion engine and carburet- I ing means for supplying, fuel thereto, or means to-facilitate starting the engine after it has been idle 'for a period,.comprising a fuel feeding means for supplying an additional amount of fuel to said fuel intake which amount is greater for a long period of idleness than for a short period, said fuel 4feeding means comprising a fuel reservoir from which fuel is supplied to said intake,

and means for causing fuel to accumulate passage, which amount is greater for a long` period of idleness than for a short period.

In witness whereof, I have hereunto subscribed my name. WESLEY WILSON.

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