US1684902A - Mixture-forming means for internal-combustion engines - Google Patents

Description

Sept 18 N28, 1,684,902

L. M. WOOLSON MIXTURE FORMING MEANS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 9 1920 2 Sheets-Sheet 1 IZ 57 ay O O O 0 an ua ufoz l'liolwbJallbalo'om E k $13 I u I (1 Ho: 1N a q Sept. 18, 1928. 1,684,902

L. M. WOOLSON MIXTURE FORMING MEANS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 9, 1920 2 Sheets-Sheet 2 Patented Sept. 18, 1928.

UNITED STATES PATENT OFFICE.

LIONEL m. wooLsoN, or DETROIT, MICHIGAN, AssIenoR To PACKARD moron CAR COMPANY, or DETROIT, MICHIGAN, A CORPORATION or MICHIGAN.

MIXTURE-FORMING MEANS FOR INTERNALC OMBUSTION ENGINES.

Applicaton filed December 9, 1920. Serial No. 429,587.

This invention relates to mixture forming means for internal combustion engines, and particularly to means for controlling the proportion of air and liquid fuel.

In internal combustion engines as used on airplanes, the carburetor is usually provided with some sort of mixture proportion control or means for lessening the feed of the liquid fuel so that the most nearly correct proportion of air and liquid fuel may be maintained when the air pressure drops as it does at the higher altitudes reached by the airplane.

\Vith the use of combustion heaters, particularly of the suction type. such as shown in Patent No. 1,448,651,dated March 13,1923, on airplane engines, it was found that the mixture for the combustion heaters, if fed by separate carburetors must also be weakened but not necessarily to the same extent as the mixture for the main carburetor. It is one of the objects of the present invention therefore to provide mixture proportion control means for such auxiliary carburetors as Well as for the main carburetor, preferably with interconnecting means for simultaneously operating the controls. B this arrangement the degree of change in t e mixture can be different in the main and auxiliary carburetors respectively and yet the mechanism may be operated in unison by a single lever.

It has also been found that a mixture control involving means for imposing a partial. vacuum on the float chamber is rather delicate in adjustment or operation and one of the objects of the present invention is to definitely limit the amount of depression which may be imposed on the float chamber in such a mixture control mechanism.

In the use of a suction operated combustion heater such as above referred to, the suction on the heater is greatest and consequently the suction on the auxiliary carburetor is greatest when the throttle valve of the engine is in nearly closed or idling position and at this time the suction is practically nothing below the throttle valve. For this reason the mixture proportion control can not be obtained for the auxiliary carburetor if variations in the float chamber depression of the main carburetor is depended upon for the purpose. It is one of the objects of the present invention to obviate this trouble by providing independently operating mixture proportion control means but which may be brought into operation simultaneously with the mixture proportion control means of the main carburetor.

Other objects of the invention Will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:

Fig. 1 is a vertical section though the intake pipe of an internal combustion engine and mixture forming and feedingmeans embodying this invention;

Fig. 2 is ahorizontal section on the line 2-2 of Fig. 1;

Fig. 3 is a section on both of the lines 33 of Fig. 1, through the caps and upper ends of the valves of the float chambers;

Fig. 4 is a section similar to Fig. 1, illustrating another form of the invention; and

Fig. 5 is a horizontal section on the line 55 of Fig. 4.

Referring particularly to Figs. 1, 2 and 3 of the drawings, 10 represents the intake pipe of an internal combustion engine and 11 is a carburetor connected to the intake pipe with the upper part forming a continuation of the intake pipe. A throttle valve 12 is arranged at a suitable point in the intake pa ssage above the mixing chamber of the carburetor.

The carburetor 11 has a float chamber 13 with a float 14 and valve 15 of the usual type and operating in the well known manner to maintain the level of liquid in the float chamber at the desired height. The liquidfuel is fed from the float chamber 13 through a conduit 16 to a nozzle 17 which is arranged in a Venturi tube 18. The main air intake 19 of the carburetor feeds the Venturi tube and an auxiliary air intake 20 feeds additional air above the Venturi tube, thus producing the desired mixture for operating the engine.

As the invention is illustrated in Fig. 1, the mixture forming means is adapted for use in an airplane or dirigible engine or other machine that is intended to operate at altitudes considerably above sea level. It is also intended for use with a combustion heatsingle combustion heater is used only one of such auxiliary carburetors would be ordinarily required. Only one of them will consequcntly be described and it is understood float chamber 22 which is shown as cast integral with the main carburetor 11, but it may be separately formed if desired. The usual float 23 and valve 24 are shown for maintaining the liquid level and an air vent 25 is shown in the cap 26 for maintaining atmospheric pressure in the float chamber. The upper end of the valve 24 is flattened as at 27 to permit the air to enter the float chamber. This is more clearly shown in Fig. 3.

' The main body piece 28 of the carburetor 21 is threaded into a boss 29 formed in the cover of the float chamber, and its lower end extends into the gasoline or other liquid fuel inthe float chamber. This lower end forms a well 30 fed by a restricted opening 31 and cross channels 32, as well as by air openings 33 at the upper part of the well. A central mixture channel 34 extends upwardly through the body and terminates 1n cross channels 35 near the upper pointed end of.

the body.' A sleeve 36. surrounds the upper part of the body and is somewhat contracted adjacent the crossrchannels 35 and terminates at its upper end in a connection 37 for a pipe 38 which conveys the mixture formed by the carburetor to the combustion heater device above referred to (not shown). Air ports 39 and vertical channels 40 supply air to the sleeve 36, which air is added to the emulsion brought up by suction through thechannel 34 to form the desired mixture for the normal operation of the combustion heater device at sea level.

It will be understood that the main carburetor 11 and the auxiliary carburetor 21, as hereinabove described, are not new in themselves and are not claimed per seherein.

Other forms of carburetors for accom lish- 'ing the same purpose may besubstituted and used with the combinations of elements hereinafter described and claimed.

For the purpose of obtaining mixture proportion control of the main carburetor 11 under various atmospheric conditions, that is, for instance, for restricting the liquid fuel feed as the air becomes less-dense, a valved connection is providedbetween the float the mixture. A valve 44'is provided in the plpe 41 to control the connection, the operation of this valve to be either automatic by y a sultable altitude device or manual by the izing the suction at the nozzle: 17. A small vent 45 is made in the cap 42 to somewhat modify the suction but even with this vent it has been found diflicult to properly control the suction and in some cases the depression in the float chamber becomes so great that too little gasoline or liquid fuel is fed to the carburetor. To ofiset this possibility and def initelyelimit the amount of depression which may imposed on the float chamber 13, a

submerged vent is provided for the float chamber. This is shown in the form of a parallel chamber 46 drilled vertically in the casting forming the float chamber, connected near its lower end with the float chamber by a port 47' and .open to the atmosphere at its upper end as through the ports 48. This is on the principle of a U-tube and it will be seen that the depression in the upper part of the float chamber will tend to lower the level of the liquidin the chamber 46 until the oint is reached when the ort 47 is uncovere and thereafter air will chamber thereby preventing further depresdrawn into the float sion therein. In this manner the maximum depression in the float chamber may be fixed without the use of minute and accurately sized orifices communicating with the atmosphere, such as are sometimes employed for this purpose.

The auxiliary carburetors 21, it is under stood, operate at, their-maximum when the main carburetor 11 is operating at its minimum, because of the greater pull on the suction operated combustion devlce at that time.

These carburetors 21 therefore are'provided with a separate mixture proportion control means, in the form of an additional air inlet 49 for each of them. These air inlets are fed by pipes 50 and a pipe 51, the intake end of the latter being controlled by a valve 52. As

shown, the valve '52-is closed which is the ground or sea level position of this altitude control device. ,As the valve 52 is gradually opened air in the desired quantities is fed to the additional air intake 49 then consequently -to the carburetor 21, thus making a leaner mixture.

The valve 44 of the main carburetor and the valve 52 of the auxiliary carburetors, are interconnected by a rod 53, and a rod 54 is provided for automatic or manual adjustment of these valves so that the control means of both carburetors may be simultaneously operated as the machine reaches the higher alti- 17, Venturi tube 18, main air intake 19and' The auxiliary carauxiliary air intake 20. buretors 21 are also'exuctly the same in 0011- struction and function. So far as maintaining the liquid level for the auxiliary carburetors 21 is concerned,the float chamber 23,

the float 23 and the valve 24 are also the same.

as in Fig. 1, and the connections and pip- ing 37 and 38 respectively, from the carburetors 21 are the same. 1

1 The mixture proportion control. for the main carburetor 11 is also substantially the same as that of Fig. 1, since there is a pipe' 41 leading from the cap 42 of the float chamber 13 to the intake pipe 10 through a restricts ed opening 43. A vent 45 is also provided in the cap 42. However, instead of breaking the connection formed by the pipe 41 for ground operation of the device, a valve is used for admitting atmospheric pressure to the pipe, as will be hereinafter described.

The float chamber 13 of the main carburetor is provided with the same submerged vent as in Fig. 1, comprising the chamber 46, port 47 and air port 48.

For the float chamber 22 there is also an air vent 25 in the cap 26 similar to Fig. 1, but instead of the control for the carburetors 21 shown in Fig. 1, this form of the invention provides a suction connection from the cap 26 to the intake pipe 10 above the throttle. This connection is in the form of a pipe connected at one end to the cap 26 and at the other end to the intake pipe 10 through a restricted opening 61. Thus the suction or depression in the intake pipe 10 above the throttle, is communicated to the upper part of the float chamber 22 in the same manner that the depression in the intake pipe 10 below the throttle valve 12 is communicated to the upper part of the float chamber 13.

With this construction, the float chamber 22 is also provided with a submerged vent for the purpose of definitely limiting the amount of depression which may be imposed on the float chamber. This submerged vent is shown in the form of a'chamber 62, a port 63 communicating with the float chamber 22 below the level of the liquid therein, and an atmosphere port 64 at its upper end. It will be seen that the submerged port.63 is somewhat lower than the corresponding port 47 of the float chamber 13 as it is frequently desirable to have a higher limit for the depression in the auxiliary carburetor float chamber than in the main carburetor float chamber.

It will be obvious that if the pipes 41 and 60 are 0 ened tothe atmosphere their efiect. on the' oat chambers 13 and 22 will be nul-' .lified and in that event said float chambers are fed normally as is desired for ground or sea-level operation. For accomplishing this channels 67 and 68 which commumc'ate respectively with the pipes 41 and .60. ,Thevalve is operated by a rod 69 either automatically or manually by the operator .a valve 65 is (provided, this valve having an" air port 66 an and as it is turned it gradually vents the pipes 41 and 60 until it is fully opened when the operation .of the suction in those pipes is entirely nullified.

An engine such, for instance, as that shown in Patent No. 1,448,651, when equipped with this invention, will have certain advantages that are of considerable importance. Thus, suppose an engine so equipped is used in an airplane operating at a ten thousand foot altitude and it is desired to glide down with the engine running idle. Under these conditions it is preferable to idle the engine during the glide rather than shut it off entirely because .under the latter condition there would be the uncertainty of starting the engine when nearing the ground and that is when it is most needed. On this glide downwardly the throttle would be nearly closed and there would be considerable suction above the throttle and practically none below it. The combustion heater is subject to the suction above the throttle valve and under these conditions, therefore, it would be operating at its maximum and this would keep the intake passages and the gas being fed to the engine at their maximum heat and the engine would not stall as its throttle is opened when nearing the ground. At the same time the engine would be getting a richer mixture from the main carburetor because of the altitude and because of the fact that there would be little suction below the throttle and consequently slight depression in the float cham-' ber. That is the kind of mixture the engine needs for idling. But the combustion heater does not require a rich mixture under these conditions because it'is operating at its maximum. If the auxiliary carburetor. that is the carburetor used for the combustion heater, operated similarly to the main carburetor, the same rich mixture would go to the 'com bustion heater and probably it would be too rich to burn and stalling of the engine just at the time the aviator needed it most. that is when nearing the ground, would probably result. With applicants invention the auxiliary carburetor is automatically controlled to give the proper mixture under these conditions and the fatal result above referred to is avoided. With applicants invention the maximum operation of the combustion heater is assured and a desirable rich mixture for the engine results, when those two conditions are most needed in the operation of an airplane.

It will' be understood that various forms other than those described herein. ma be used without departing from the spirit or sco of the invention.

aving thus described my invention, what I claim and desire to secure by Letters Patcut is:

1. In an internal combustion engine the combination with two float chambers and two carburetors connected thereto respectively, mixture proportion control means connected to both of said float chambers and a single valve for operating said control means to vary the mixture proportions.

2. In an internal combustion engine, the combination with an engine intake pipe having a throttle valve therein, a carburetor connected to said pipe to supply mixture thereto and having a float chamber, a second float chamber, a carburetor fed by said second float chamber, a pipe connection between one of said float chambers and the intake pipe below the throttle valve, and a pipe connection between the other said float chamber and the intake pipe above said throttle valve.

3. In an internal combustion engine, the combination with an engine intake pi e having a throttle valve therein, and a car uretor connected to said intake pipe and having a float chamber. a carburetor adapted to suply a combustion heater having a float chamer, a pipe connection from the main carburetor float chamber to the intake pipe below the throttle valve. and a pipe connection from the second named carburetor float chamber to the intake pipe above the throttle valve.

4. In an internal combustion engine, the combination with an engine intake pipe having a throttle valve therein, and a carbu- 7 retor connected to said intake pipe and having a float chamber, a carburetor adapted to supply a combustion heater having a float chamber, a pipe connection from the main carburetor float chamber to the'intake pipe below the throttle valve, a pipe connection from the second named carburetor float chamber to the intake ipe above the throttle valve, and valve contro led means for breaking the suction in both of said pipe connections.

5. In an internal "combustion engine,-the combination with the intake pipe thereof having a throttle valve, of a carburetor connected to said intakepipe and having a vented float chamber, a pipe connecting the upper part of said float chamber to the intake pipe below the throttle valve, a valve in said pipe, and a submerged vent means for the float chamber.

6. In an internal combustion engine, the' combination with the intake pipe thereof havin a throttle valve, of a carburetor connecte to said intake pipe and having a vented float chamber, a pipe connecting the up er part of said float chamber to the intake plpe elow the throttle valve, a valve in said pipe, 55

one of said float chambers with said intake pipe below the throttle valve thereof, means connecting the upper part of the other said float chamber with the intake pipe above the throttle valve thereof, and submerged vent' means for each of said float chambers.

8. In an internal combustion engine, the

combination with the engine intake pipe, of

mixture forming means comprising two float chambers, means connecting the upper part of one of said float chambers with sald intake pipe below the throttle valve thereof, means connecting the upper part of the other said float chamber with the intake pipe above the throttle valve thereof, and submerged vent means for each of said float chambers, the

submerged vent of one of said submerged vent means being lower than that of the other.

9. In an internal combustion engine, the combination with the engine intake pipe, of

mixture forming means comprising two float chambers, means connecting the upper part of one of said float chambers with said intake pipe below the throttle valve thereof, means connecting the upper part of the other said float chamber with the intake pipe above the throttle valve thereof, and submerged vent means for each of said float chambers, the submerged vent means of the last mentioned float chamber being lower than the other submerged vent means.

In testimony whereof I afiix my signature.

LIONEL M. WOOLSON.

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