US2675216A

US2675216A - Carburetor throttle cracker

Info

Publication number: US2675216A
Application number: US229356A
Authority: US
Inventors: Olin J Eickmann
Original assignee: Carter Carburetor Corp
Current assignee: Carter Carburetor Corp
Priority date: 1951-06-01
Filing date: 1951-06-01
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13

Description

April 13, 1954 Filed June 1, 1951 O. J. EICKMANN CARBURETOR THROTTLE CRACKER 4 Sheets-Sheet l INVENTOR. OLIN J. EICKMANN ATTORNEY Ap 13, 1954 o. J. EICKMANN 2,675,216

CARBURETOR THROTTLE CRACKER Filed June 1, 1951 4 Sheets-Sheet 2 JNVENTOR. OLIN *J. EICKMANN ATTORNEY April 1954 o. J. EICKMANN 2,675,216

CARBURETOR THROTTLE'CRACKER Filed June 1, 1951 4 Sheets-Sheet 5 FIGS 33 INVENTOR. OLIN J. EICKMANN k ww ATTORNEY April 1954 o. J. EICKMANN 2,675,216

CARBURETOR THROTTLE CRACKER 4 Sheets-SheetA Filed June 1 1951 INVENTOR. OLIN J. EICKMANN ATTORNEY Patented Apr. I3, 1954 UN ITED STATES PATENT OFFICE.

CARBURETOR THROTTLE CRACKER;

011ml. EickmanniNormandy, Mo., assignor to. Carter Carburetor Corporation, St. Louis, Mo.,. a corporation of Delaware Application June 1, 1951, SerialNm 229,356.

This invention relates to internal. combustion engine carburetors of the anterior throttletype and consists in novel throttle control means therefor, particularly, to facilitate. starting.

It has been foundthat in a downdraft carburetor of the anterior throttle type, fumesv may collectbeneath the throttle valve, particularly, in warm weather, and hinder restartingv of the engine. Another problem in some. carburetors. of this type is-that the-throttle valve, normally manually controlled, must not be opened during starting at very low temperatures.v

Accordingly, the'main object of the present invention is to provide "a novel throttle control mechanism which insures slight opening or cracking of the 'throttle valve, after the engine is stopped, for venting vapors.

Another object is to provide a thermostatic control for such a throttle-cracking device so that the throttle may be returned to substantially fully closed position atlow 'temperatures to facilitate starting.

Another object is to provide stop means for positively preventing opening of the throttle valve, atlow temperatures, until the engine starts to run.

These objects and other more detailed objects hereafter appearing-areattained by the mechanism illustrated in the accompanying drawings in which Fig. 1 is a side view-showinga portion of the manifolding of an internal combustion engine with an anterior throttle carburetor mounted thereon.

Fig. 2 is an enlarged top viewof the carburetor.

Fig. 3 is a vertical, transverse section taken on line 3-3 of Fig. 2.

Fig. 4. is a detail elevation-taken on line 4-4 of Fig. 3. Fig. 5 is a side view of the carburetor show- 'ing the throttle valve and related parts in their fcold cranking-positions, portions being broken away and sectioned for clearer illustration.

weather starting;

Fig. 9 is'a view of thesameparts as in Figs. "7

and 8; but showing" the throttle control parts 8 Claims. (Cl; 261-.39)

during normal operationof. the associated engine.

Fig. 1 shows portions ofv anintake manifold l0 and exhaust manifold .II which join in a hot spot structure 12 upon whichismounted the carburetor, generally indicated at 13. A stove It, mounted on the exhaust manifold, .isconnected by a tube I5 to a thermostat housing Hi, to. be described. An accelerator rod. I]. extends from the driver's compartment and is. connected through a coiled spring l8andznut stops, l9. toa lever so which is loosely mounted about throttle shaft 2! (Fig. 5).

Rigid with throttle shaftll and immediately adjacent lever isa secondlever 22 having a radial extension23 with. an. inturned finger 24. This finger is constantly urged against a radial finger 25, projecting fromthe periphery of loose lever, 20 by a torsion spring. 26 having its ends hooked about

fingers

24 and 25, as shown. An idle adjusting screw 21 is received by. threaded ears 28 on lever 20 and engages a. stop29 on the carburetor body tolimit the closed or normal idling position of the throttle valve.

A butterfly throttle valve 3| is mounted on shaft 2! in the air entrance portion. 32. of the carburetor mixture conduit. Adjacent the mixture conduit, is a constant level chamber 33 within which fuel is maintained at a substantially constant level by a float 34 and needle valve mechanism (not shown). Main fuel, nozzle 35 (Fig. 3) projectsupwardly and inwardly from the lower part of the constant levelchamber and discharges into the throatof primary Venturi tube 36.

Leading upwardly from the mainfuel nozzle is an air bleedductfll which communicates with the mixture conduit adjacent the edge of the throttle valve by means of the vertically spaced, differently sized ports 38"and is-connected by passages 39 and 40 (Fig. 2) to a tube 41 projecting into the mixture conduit.

"a needle valve screw 50. A branch passage 5| connects passage flto the top of 'a constant level chamber 33. A thermostatic, bi-metal coil 52 mounted within housing It has its outer extremity hooked about and arranged to actuate an an gular finger 53 rigid with drum valve 45. The thermostat is heated by warm air from stove l3 and tube [5 to shift the drum valve to increase the effective size of the communication through slot 46 between passages 44 and 4'! connecting the mixture conduit and the space at the top of the fuel bowl. At low temperatures, this efiective communication is reduced to a minimum and a port 54 in the drum valve admits air from housing [6 into the mixture conduit. Much of the above, with the exception of the throttle control parts, is covered in a copending application, Serial No. 164,544, filed May 26, 1950, in my name.

Formed on the outside of the mixture conduit is .a vertical cylinder 58 communicating by means of a passage 51 with the interior of the.

mixture conduit. A piston 58 works in the upper part of this cylinder and normally projects thereabove. The piston is urged upwardly by a compound, coiled, bi-metal spring 59, shown in detail in Fig. 6, which is of the character to extend along its principal axis, upon increase of temperature, to urge piston 58 upwardly.

Figure 8 shows the condition of the parts when the engine is stopped at high temperature with accelerator rod I! fully relaxed to permit maximum clockwise rotation of throttle loose lever 20 by means of return spring 66. Due to the elevation of piston 58, which underlies and interferes with inward finger 24 on rigid lever 23, the throttle valve, if open when the engine stops, can return only to the adjusted position shown in dotted lines, torsion spring 25 flexing to permit this relative movement of the two throttle levers. Ordinarily, the engine is stopped with the throttle closed; however, when suction is not present in cylinder 56, the thermostat spring 59 tends to expand when the engine is hot, which will raise piston 58 to open the throttle 3i from its idle position to its venting position against the resistance of spring 26.

Figure 5 shows piston stop element 58 in its lowered position, as under cold temperatures, permitting tight lever 23 to rotate clockwise suificiently so that the throttle valve may be fully closed under the influence of its return spring, when the accelerator is released, permitting adjusting screw 21 to engage stop 29. Figs. 5 and 3 illustrate the two extreme posi-- tions of the

throttle adjusting device

58 and 59. The tension in actuating spring 59 depends on engine temperature. Accordingly, the force it exerts, tending to open, or tending to resist, throttle closing, as the case may be, will depend upon temperature. It is wholly possible, therefore, for the throttle to assume other positions between these extreme positions as the engine cools or is stopped before reaching full operating temperature.

In the fully closed position of the throttle, a detent 6|, which works in a cylinder 62 and is urged constantly upwardly by a coiled spring 53, enters a recess 64 in the periphery of loose lever 25. As shown in Figure 7, engagement of detent 6| with the inclined shoulder 65 of recess 64 impedes counter-clockwise motion of loose lever 25 and, consequently, opening movement of the throttle valve. If accelerator link i! is actuated in the throttle opening direction, spring I8 is first compressed, as shown, while the throttle remains closed, or opens only slightly. However, upon extreme actuation of the accelerator link in the throttle opening direction, sufficient force will be built up in spring l8 to cause inclined shoulder 66 to ride over detent 6|, permitting opening of the throttle valve, as in case it is necessary to unload excess fuel which may be discharged into the manifold during starting. This latching of the throttle in closed position is desirable at low temperatures in order to facilitate starting. Cylinder 62 is connected by a passage 61 to the interior of the mixture conduit so that when the engine starts to run under its own power, sufiici-en't suction will be created within the mixture conduit to draw detent Bl downwardly, thus releasing the throttle valve for complete opening movement under the influence of accelerator linkage I1. I

The latching of the throttle valve in a partially open position, as in Fig. 8, is desirable in order that any fumes rising from the manifold or from the main'fuel nozzle will not be trapped beneath the throttle valve so as to impede restarting. Granking suction applied to piston 58 will tend to lower the same against the thermostatic spring and, at moderate and high temperatures, the piston stop element will be lowered sufficiently during cranking to permit closing of the throttle valve, by return spring lit, to the desirable position for starting. When the engine is operating normally under its own power, both piston 58 and detent 6| will be drawn downwardly to their non-stopping positions to permit free actuation of the throttle valve under the influence of the accelerator linkage and return spring, as usual.

The thermostatic spring may be calibrated to provide for the proper starting position of the throttle valve under various temperatures. Broadly, another type of device responsive to operation of the engine, such as a motor responsive to oil pressure or a magnetic device responsive to generator output, may be .substituted for the

suction motor

56, 58 for counteracting the warm thermostat after the engine is in operation. Moreover, the exact type of thermostat as shown is not essential and other types may be substituted. Some features of the invention are applicable to other types of carburetor mixture conduit valves, other than the anterior throttle, as shown. The exclusive use of all modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In combination with an internal combustion engine, an air supply conduit a throttle valve in said conduit for controlling the flow of air to said engine, a fuel nozzle discharging below said valve, means for moving said valve towards closed position, a part movable with said valve, a device cooperating with said part for adjusting the position of said valve when the engine is at rest to provide for venting vapors from said conduit, said device including a mechanism connected to said-device and responsive to operation of the engine to shift said device to an inactive position with respect to said part.

2. In combination with an internal combustion when the engine is at rest to provide for venting vapors from said conduit, a second conduit for conducting a flow of fluid upon operation of the engine, including a means responsive to fluid fiow in said second conduit to shift the adjusting position of said device with respect to said part.

3. In combination with an internal combustion engine induction conduit, a flow controlling throttle valve therein, a fuel discharge nozzle in said conduit below said valve, manual means to open said valve and spring means for moving said valve toward closed position when said manual means is released, a device cooperating with said part for adjusting the position of said valve when the engine is at rest to provide for venting vapors from said conduit, and means connected to said device and said conduit and responsive to suction in said conduit to shift said device to permit further closing of said valve.

4. In combination with an internal combustion engine, an air supply conduit a valve in said conduit for controlling the flow of air to said engine, a fuel nozzle discharging into said conduit below said valve, manual means to open said valve and means for moving said valve towards closed position whenever said manual means is released, a part movable with said valve, a device cooperating with said part for adjusting the position of said valve when the engine is at rest to provide for venting vapors from said conduit, said device including a mechanism connected to said device and responsive to operation of the engine to shift said device to an inactive position with respect to said part, said device incorporating a thermostat adapted to vary the adjusted position of said part and said throttle when the engine is not in operation.

5. In combination with an internal combustion engine, an air supply conduit, a valve in said conduit for restricting the flow of air to the engine, a fuel nozzle discharging below said valve, means to move said valve towards closed position when the engine is at rest, a part movable with said valve, a throttle adjusting element movably mounted adjacent said part and cooperable therewith to hold said valve at least partly opened when in active position, a second conduit for accommodating a fluid flow incident to actuation of the engine, a fluid motor operatively con nected to said conduit and said adjusting element, for shifting said element upon operation of the engine, to permit further closing of said valve, and a thermostatic spring constantly urging said adjusting element towards its active position, said position being such as to hold said valve partly open at high temperature for venting vapors rising from said nozzle into said air conduit and to permit substantial closing of said valve at low temperatures.

6. In a carburetor for internal combustion engines, a mixture conduit, a manually operable throttle valve in said conduit near the air entrance thereof, a fuel reservoir, a main fuel nozzle extending upwardly from said reservoir and discharging into said conduit posterior to said valve, a lever movable with said valve, a throttle adjusting element cooperable with said lever, a throttle return spring, a thermostat normally urging said element to an active position, at high temperature to position said valve at least partly opened for venting vapors issuing from said nozzle, and a suction motor operatively connected to said conduit and said adjusting element for shifting said element from its active position upon actuation of said motor, said thermostat shifting said element to a position when the temperature is low, to permit closing movement of said valve by said return spring.

7. In a carburetor for internal combustion engines, a mixture conduit, a throttle valve in said conduit near the air entrance thereof, a fuel reservoir, a main fuel nozzle extending upwardly from the reservoir and discharging into said conduit posterior to said valve, a lever movable with said valve, a throttle adjusting element cooperable with said lever, a throttle return spring, a thermostat normally urging said element to an active position, at high temperature, to force said valve at least partly opened for venting vapors issuing from said nozzle, and a suction motor operatively connected to said conduit and said adjusting element for shifting said element from its active position upon actuation of said motor, said thermostat responding to a drop in temperature to reduce its resistance to movement of said adjusting element by said suction motor so that cranking suction in said conduit will shift said adjusting element and permit substantial closing of said valve by said throttle return spring to facilitate starting.

8. In a carburetor, a mixture conduit, an anterior throttle therein, a main fuel nozzle discharging into said conduit posterior to said valve, a manual control yieldingly connected to said throttle for opening the same, a throttle return spring, a thermostatically controlled stop for limiting closing of said valve at high temperatures when said manual control is released, a second stop for limiting opening of said valve,

and suction motor means responsive to suction in said conduit for shifting both of said stops upon operation of the engine, to permit control of said valve by said manual control and said return spring.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,393,290 Chandler Jan. 22, 1946 2,403,720 Hunt July 9, 1946 2,540,607 Boyce Feb. 6, 1951