US2148265A

US2148265A - Carburetor and priming device

Info

Publication number: US2148265A
Application number: US703778A
Authority: US
Inventors: Willard B Goodman; Miller Jeptha Mackenzie
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1933-12-23
Filing date: 1933-12-23
Publication date: 1939-02-21
Anticipated expiration: 1956-02-21

Description

2 Sheets-Sheet l JNVENToRs.

A TToRNEx Feb. 21,A 1939. w. B. GOODMAN ET A1.

CARBURETOR AND PRIMING DEVICE Filed Dec. 2s, 195s HS n Feb. 2l, 1939. y w4 B, GOODMAN ET'AL 2,148,265

CARBURETOR ND FRIMTNG DEVICE Filed Dec. 23, 1953 E- Sheets-Sheet 2 I /706 /oo /Ol Q/FTW 5 i O 0,; [96

` 04 /ogrz/ To 86 CYLlNDERS IN V EN TORS.

' Q ATTI'ORNEY.' y

Patented Penal, 1939 e y,UNITED STATES PATENT OFFICE CARBURETOR AND PRIMING DEVICE Willard B. Goodman, Paterson, N. J., and Jeptha Mackenzie Miller, South Bend, Ind., assignors to Bendix Aviation Corporation, South Bend, Ind., a. corporation of Delaware Application December 23, 1933, Serial No. 703,778

4 Claims.

In many of the larger high-compression inter- Y nal-combustion engines it is very diicult to secure a mixture in the cylinders that is sufficiently rich to support combustion when the engine is cold.

An object of this invention is to provide an apparatus whereby liquid fuel may be injected into the cylinders to facilitate starting of the engine.

A further object is to utilize the conventional acceleration pump of the carburetor to supply a priming charge directly to the inlet ports of the engine under certain conditions of operation.

A still further object is to provide a priming device of simplified construction, which may be formed integrally with the body portion of the carburetor.

The above and other useful and novel features of this invention will appear more fully from the following detailed description when taken in connection with the accompanying drawings, in

which:

Figure 1 is an elevation showing the invention applied to anvairplane engine;

Figure 2 is a section showing the construction of the priming device; .1

Figure 3 illustrates a modified form of the invention;`

Figure 4 is an enlarged sectional view showing the valve used in connection with the modication a shown in Figure 3;

Figure 5 is a modification similar to Figure 3 embodying Aa different arrangement;

Figure 6is a section on line 6---6 of Figure 5;

Figure 7 is a section. on line 'I-l of Figure 6v showing the position of the valve when discharging to the fuel nozzle of the carburetor;

Figure 8 is a section similar to Figure 'lv show- Figure 11 is an'exploded'view ofthe severall fparts vconstituting the altitudelmixture control valve.

Referring more particularly to Figure 1, there'v is shown, for the purpose of illustrating this invention, a carbureting device embodying the inventionas used on an airplane engine; A primreservoir 36.

(Cl. D23-187.5)

ing device 58 is associated with the acceleration pump unit 80 of the carburetor and discharges directly to the cylinders of the engine through fuel ducts52 and 56 which are fixed in the intake manifold-54.

Figure 2 shows a carburetor having a body portion I0 forming a main carbureting passage I2 in which are positioned the usual venturi I4 and fuel discharge nozzle I6. A throttle valve I8 of the butterfly type is mounted on shaft 20, which is journaled in the walls of the main carbureting passage I2. lFixed to shaft 20 is a double-armed crank 22, one arm of which connects with rod 24, by means of which the throttle valve I8 is actuated. The other arm of crank 22 connects through link 26 to an acceleration lpump which may be of vany desired construction, but which in the illustrated embodiment comprises a piston rod 28 and-a piston 30 which is slidable in a cylinder 32. Fuel is admitted to cylinder'32 through a check valve 34 which communicates with fuel Piston 30 is slidably mounted on rod 28 and is yieldingly urged downwardly by a compression spring 38, the upper end of which abuts against a washer 40. The pump discharges througlipassage 42 to the fuel nozzle I6, the discharge passage being controlled by a pressureresponsive outlet valve 44 designed to be opened veither by fuel pressure or by flange 46 on the rodv 28 contacting with the projecting stem 48 of the valve 44 (see Figure 10).

In order to adapt'the acceleration pump just v described to be used as a priming pump, a second discharge passage 50 leads from the cylinder 32 and connects by a duct 52 and manifold 54 to a plurality of ducts 56 leading to the intake manifold of the engine adjacent the respective inlet ports of the cylinders. p y

The passage 52 is controlled by a pressureresponsive valve mechanism which comprises a shell 58 forming a chamber 60 in which piston 62, having a valve point 64, is yieldingly urged tothe lower extremity of chamber 160v by spring 66,

which is hrld in chamber 6 0 by a cap screw 68. A vent 10 is located in the upper `portion of shell 58 to prevent air lock in'chamber `Ill when piston 62 slides therein.

To prime and tart the engine the operator will actuate the th ottlelever 16, thus operating the acceleration pump by means ofthe above-described mechanism. A portionof the acceleration fuel will thereupon be ejected through fuel nozzle I6, but due to the factthat passage 42 is restricted by valve 44,"a larger portion of thel fuel will pass through duct 5II 'to chamber I2 where the resulting pressure will force piston 62 upwardlyin cylinder 80, compressing spring 66 and opening passage 52 so that fuel will be forced to the inlet ports of the cylinders.

When the priming operation has been completed, the operator sets the throttle in the proper position and starts the engine. When the engine starts, suction will be transmitted through duct 52 which, together with the force of spring 66, will hold valve point 64 in contact with valve seat 14 and prevent the further flow of fuel through said valve. 1f the acceleration pump is then actuated, it will discharge to the fuel discharge nozzle I6 of the carburetor through check valve 44 and fuel duct 42.

Figure 3 illustrates a modification of an acceleration pump which is actuated by the throttle mechanism through a linkage consisting of rod double-armed crank |00 and rod |04, the upper portion of which is made of flexible material such as a flexible cable wound circumferentially by a tight coiled spring, giving an appearance similar to a conventional Bowden conduit.

'I'he acceleration pump 80 discharges to a fuel duct 82 leading to valve member-84, which is of the type shown in Figure 4. An arm 98, fixed to valve member-84 in such a manner as to actuate it, is pivotally connected with arm 86 by link 88. Arm 86 .is flxed to the shaft 80 of a conventional mixture control mechanism and is actuated by arm 92 and rod 93, which is manually operated through suitable control mechanism at the operators position. Two offset stops 81, formed on the lever 86 are engaged by arm 92 to move valve 84 when rod 93 is actuated. The operation of this device is as follows. When it is desired to prime the engine, the operator moves the mixture control rod 93 to lean position, thereby rotating arm 86 in the clockwise direction, and through the link 88, rotating arm 98 in a counterclockwise direction 5to move the valve 84 to the position shown in dotted lines on Figure 4, thereby opening the fuel duct 94 and closing oil the fuel duct 96. Duct 94 leads, through connections similar to those shown in Figure 2, to a plurality of jets in the intake manifold adjacent the inlet prts of the engine. The operator will then open the throttle valve, thereby operating the acceleration pump by means of the connecting mechanism and pumping fuel through check valve I I2 and fuel duct 82 to valve 84 where it is directed through the passage shown in dotted lines on Figure 4 to fuel line 94 leading to the inlet ports of the engine.

When the priming operation has been completed, the operator moves the mixture control lever on the instrument board (not shown) to full rich position, thereby rotating arm 86 in the counter-clockwise direction and rotating crank 98 in the clockwise direction through link 88, to move the valve 84 to the position shown in full lines on Figure 4, closing fuel duct 94 and opening fuel duct 96. The acceleration pump 80 will then discharge to the fuel discharge nozzle 91 through fuel duct 96. A

Figures 5-9 illustrate a valve mechanism riperable in conjunction with the altitude mixture control mechanism of an aircraft carburetor for selectively opening and closing a plurality of ports v in a fuel line leading from the acceleration pump.

annular groove |34 is cut in the valve member |22 for approximately three-quarters of the circumference, to permit fuel to enter said passage from the acceleration pump discharge duct |36,

and discharge through either of two ports |40 and |42 leading to the main carbureting passage or the cylinders lof the engine;

When therotatable portion |54 of the valve member |56 is moved to a position to close the communication with atmosphere, the fuel reservoir is subjected to the variations of fluid pressure existent in theinduction passage of the carburetor. The pressure to which the fuel in the float chamber is subjected is therefore decreased, whereupon less fuel will be supplied to the induction passage. The pressure in the induction passage isv dependent, in part, on the barometric pressure of the atmosphere -in which the device is operating, and since the quantity of fuel supplied is dependent in part on the pressure in the induction passage, the fuel to air yratio of the mixture supplied by the carburetor is controlled in accordance with variations in barometric pressure. An altitude mixture control is thus effected.

The operation of this device is as follows. To prime the engine the operator rotates the shaft |24 by means of arm |31 and other mechanism (not shown), to move the altitude mixture control mechanism to lean position, thereby moving the valve member |22 to the position shown in Figure 8, to close the duct |40 and open the duct |42. It is thus apparent that when the acceleration pump is actuated by movement of the throttle lever it will discharge fuel directly to the inlet ports of the engine, thereby producing a rich mixture for starting purposes.

'When the priming operation has been completed, the operator moves the altitude mixture control to the rich" position, thereby rotating the shaft |24 in the counter-clockwise direction and rotating the valve member |22 to the position shown in Figure 7, to close the duct |42 and to open the duct |40. The acceleration pump will then discharge to the fuel nozzle of the carburetor. The appropriate throttle valve setting is then made and the engine started.

With the devices illustrated and described it is possible to pump liquid fuel direct to the engine to obtain a mixture that is sufficiently rich to start the engine.

It is expressly understood that the scope of this invention is tol be restricted by nothing appearing herein except the appended claims.

We claim:

1. In an internal combustion engine, a .plurality of cylinders and a carburetor having a manually actuated acceleration pump, a chamber communicating with the acceleration pump, connecting means between said chamber and cylinders, and pressure responsive means in said chamber adapted to normally close said connecting means and to interconnect .said acceleration pump and cylinders when a predetermined pressure is established in the acceleration pump.

2. In an aircraft engine, an intake manifold, a carburetor having a main carbureting passage, means including a fuel nozzle for supplying fuel to the carbureting passage, acceleration means for supplying an increased quantity of fuel to the carbureting passage under certain conditions of operation, connecting means between the acceleration means and' the intake manifold, and

v pressure responsive means controlling the connecting means to supply fuel directly to the intake manifold from the acceleration means under certain conditions of operation.

3. In combination with a carburetor including a fuel reservoir, means forming a main induction passage and a discharge nozzle for a multicylinder internal combustion engine, an altitude mixture control Vmechanism including a shaft and means to subject the fuel reservoir to iiuid pressures existent in the main induction passage, an acceleration pump, a. priming device mounted on said shaft and comprising means to selectively supply fuel from the acceleration pump to the cylinders of the engine and to the discharge nozzle, and manually operable means to actuate said shaft to control the priming device and the altitude mixture control mechanism.

4. In combination with an aircraft carburetor, including a fuel reservoir, a throttle, and means forming an induction passage for a multi-cylinder engine, an altitude mixture control mechanism comprising manual means to selectively subject the fuel reservoir to variations in uid pressure in the induction passage o r to atmospheric pressure, a manually operable acceleration pump operated in accordance With throttle position, and a priming device associated with and dependent on the position of the altitude mixture control mechanism to ydeliver fuel from the accelerationpump to the cylinders of the engine or to the induction passage of the carburetor.

WILLIARD B. GOODMAN.- -JEPTHA MACKENZIE MILLER.