ANTISMOG CARBURETOR
United States Patent 3618907
A vacuum-controlled valve is adapted to cut off the admission of fuel to a carburetor idling jet when the motor vehicle is decelerated and vacuum in the intake manifold is high. The engine thus acts as a brake, and when deceleration takes place to a predetermined extent, the drop in vacuum, that is, increase in pressure in the intake manifold, opens the valve to admit fuel to the carburetor to prevent the motor from stalling.
US Patent References:
Fuel-supply device for explosion motors
Hansen-Ellehammer - June 1924 - 1499173
Carburetor
Skoogh - October 1934 - 1933395
Automatic fuel interrupting device for explosion engines
VonHilvety - September 1937 - 2094555
Internal combustion motor system
Jacobs - October 1937 - 2095746
Carburetor device
Read - July 1940 - 2208702
Fuel-supply device for explosion motors
Hansen-Ellehammer - June 1924 - 1499173
Carburetor
Skoogh - October 1934 - 1933395
Automatic fuel interrupting device for explosion engines
VonHilvety - September 1937 - 2094555
Internal combustion motor system
Jacobs - October 1937 - 2095746
Carburetor device
Read - July 1940 - 2208702
Application Number:
04/794604
Publication Date:
11/09/1971
Filing Date:
01/28/1969
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
261/DIG.019, 261/69.100, 123/326
International Classes:
F02M3/05; F02M3/00; F02M7/12
Field of Search:
261/69,39,41,49,51,50.1,41.4 123/97
US Patent References:
| 2320012 | Carburetor | May 1943 | Riall | |
| 2751201 | Coasting economizers | June 1956 | Hettler | |
| 2877997 | Device for controlling the admission of fuel into internal combustion engines | March 1959 | Kane, Jr. et al. | |
| 3265373 | Carburetor having idle fuel control means | August 1966 | Walker et al. | |
| 3284062 | Fuel metering control for a constant metering force carburetor | November 1966 | Obermeyer, Jr. | |
| 3517653 | DEVICE FOR INTERRUPTING IDLE FUEL CIRCUIT OF A CARBURETOR | June 1970 | Ariga et al. |
Primary Examiner:
Miles, Tim R.
Claims:
I claim
1. A carburetor having a mixing passage and a float chamber, an idling jet, a duct connecting said float chamber to said idling jet, means for completely disconnecting said idling jet from said float chamber when intake manifold pressure is below that occurring during normal engine idling, said means including a valve with a vertically extending stem projecting through the top of said float chamber, said valve and said stem being vertically movable only, a cam engaging said stem at its upper end and being movable, and vacuum-responsive means engaging said cam for movement to release said stem downward by gravity, said cam solely horizontally movable and provided with a high point normally having mechanical engagement with said stem to hold said valve in open position.
1. A carburetor having a mixing passage and a float chamber, an idling jet, a duct connecting said float chamber to said idling jet, means for completely disconnecting said idling jet from said float chamber when intake manifold pressure is below that occurring during normal engine idling, said means including a valve with a vertically extending stem projecting through the top of said float chamber, said valve and said stem being vertically movable only, a cam engaging said stem at its upper end and being movable, and vacuum-responsive means engaging said cam for movement to release said stem downward by gravity, said cam solely horizontally movable and provided with a high point normally having mechanical engagement with said stem to hold said valve in open position.
Description:
BACKGROUND OF THE INVENTION
It is well known that carbon monoxide and other noxious gases are discharged from a motor vehicle engine at a relatively high rate when the foot is removed from the accelerator pedal and the vehicle is decelerated. This, of course, is due to the relatively high degree of vacuum in the intake manifold which causes excessive flow of fuel to the vehicle through the idling nozzle of the carburetor, it being impossible for complete combustion to take place in the absence of sufficient air. This causes a high rate of discharge of carbon monoxide and other noxious gases and tends to cause smogging and substantially pollutes the atmosphere.
SUMMARY OF THE INVENTION
Fuel is admitted from the float chamber of the carburetor both to a carburetor running jet and to an idling jet just beneath the throttle valve. A vertically movable valve stem has a valve at the bottom thereof and is movable downwardly to close communication between the float chamber and the idling nozzle. The valve stem projects upwardly through the float chamber and is provided with a roller at the top thereof engageable by a cam to be normally held open. This cam is connected to the diaphragm of a vacuum motor having a chamber communicating with the intake manifold to be influenced by the degree of vacuum therein. During deceleration of the vehicle with the accelerator pedal released, vacuum in the intake manifold increases to a substantial extend, for example, to 221/2 inches of mercury. Under such conditions, the diaphragm of the vacuum motor moves the cam to drop the valve to closed position. This completely cuts off the admission of fuel to the carburetor through the idling jet and the vehicle engine accordingly acts as a brake. When the vehicle has decelerated to a predetermined extent, there will be a drop in vacuum in the intake manifold, that is, an increase in pressure, in which case the diaphragm returns to normal position and opens the valve referred to to admit fuel through the idling jet, thus preventing motor stalling and providing sufficient fuel for idling.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a sectional view through a carburetor, substantially simplified for the purpose of illustration, parts being shown in elevation;
FIG. 2 is a section on line 2--2 of FIG. 1, and
FIG. 3 is a section on line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the numeral 10 designates a downdraft carburetor as a whole having a mixing passage 12 in the upper end of which is mounted the usual choke valve 14. Passage of air and fuel downwardly through the carburetor is controlled by a conventional throttle 14' mounted on a pivot shaft 16 to which is connected a crank arm 18, the lower end of which is pivotally connected to a rod 20 conventionally leading to the usual accelerator pedal. Depression of such pedal swings the crank arm 18 to a clockwise direction to open the throttle valve 14'.
The carburetor is enlarged at tone side as at 22 to provide a float chamber 24 having a float 26 therein conventionally connected to an inlet valve (not shown) to control the admission of liquid fuel into the float chamber through an intake pipe 30.
The float chamber is provided with an outlet 32 leading in turn to a running jet 34 opening into the mixing passage 12, the passage 32 also being connected to a passage 36 leading to an idling jet 38 opening into the passage 12 just below the adjacent edge of the choke valve 14. The upper end of the passage 36 is provided with a valve seat 40.
A vertically slidable valve 42 is movable downwardly as described below to close the valve seat 40 and thus close the passage 36. Two of the valves 42 and associated elements are employed with a two-barrel carburetor, and the valve 42 in FIG. 1 may be considered to be one of such valves. The two valves for such a carburetor are shown in FIG. 3.
Assuming that the device is used on a two-barrel carburetor, each valve 42 will be provided with an upwardly extending stem 44 tied together as at 46. The stems 44 project upwardly through the cover plate 48 of the float chamber and then inwardly at their upward extremities as at 50 to engage in an axial opening in a roller 52 for which they form supporting shafts.
The roller 52 engages the top of a cam, indicated as a whole by the numeral 54, having a horizontal high portion 56, and the cam slopes downwardly towards it right-hand extremity in FIG. 1 as at 58. The right hand extremity of the cam is flattened as at 60 and slides over a rib 62 formed on the cover 48 of the float chamber.
The cam 54 is provided with a straight shank 64, as shown in FIGS. 1 and 2, and is connected at its extremity to a flexible diaphragm 68 of a vacuum motor 70. The vacuum motor 70 comprises a pair of casing members 72 and 74 in the latter of which is arranged a spring 76 biasing the diaphragm 68 to the right in FIG. 2 and is limited by a stop 78 to normally position the cam surface 56 as shown in FIG. 1. The casing 74 communicates through a nipple 80 with a flexible hose 82, the other end of which is connected to the intake manifold.
OPERATION
As stated, the cam surface 56 is normally positioned as shown in FIG. 1, holding the valves 42 in their upper or open position. Liquid fuel accordingly may flow to both jet nozzles 34 and 38, the latter of which primarily functions when the throttle valve 14' is in idling position. When the vehicle is being driven, the vacuum in the intake manifold will be relatively low and differential pressure acting on opposite sides of the diaphragm 68 will not be sufficient to overcome the loading of the spring 76.
When the vehicle is to be decelerated, the operator will remove his foot from the accelerator pedal in which case the throttle valve 14' moves to the idling position, shown in FIG. 1. Therefore, the relatively high vacuum in the intake manifold, communicating with the lower end of the mixing passage 12, causes too rapid a flow of fuel through the nozzle 38, atmospheric pressure being present above the level of the fuel in the float chamber 24. The relatively high vacuum in the intake manifold communicated to the casing 74 of the vacuum motor 70, will now cause the diaphragm 68 to be subjected to atmospheric pressure at its right side in FIG. 2 and the diaphragm will move against the spring 76 to move the cam 54 to the left in FIG. 1. The sloping portion 58 of the cam will now move beneath the roller 52, permitting this roller to drop together with the stems 44 and valves 42. No liquid fuel accordingly will be admitted to the passage 36 and accordingly the engine will be used as a brake without the admission of fuel to the intake manifold and engine cylinders. It is under such conditions that excess fuel is fed to the engine and lack of air prevents complete combustion of the fuel with the resultant discharge of noxious gases from the engine exhaust pipe. With the present device, no fuel is supplied to the engine, hence there will be no noxious fumes discharged through the exhaust pipe.
When vehicle deceleration has taken place to a predetermined point so that there is a drop of vacuum in the intake manifold below, for example 211/2 inches of mercury, the differential pressures affecting the diaphragm 68 will no longer be sufficient to compress the spring 76, and the latter will move the diaphragm 68 and cam 54 back to its normal position, shown in FIG. 1, whereupon the idling jet 38, or jets in the case of a multibarrel carburetor, will be opened to admit fuel to the passage 12. This prevents the stalling of the engine and restores normal operation of the vehicle engine.
As is well known, an appreciable waste of liquid fuel occurs during deceleration of a vehicle. With regular carburetors, there is a substantial rate of flow of fuel into the mixing passage, which not only results in exhausting noxious fumes, as stated, but performs no useful function. With the present carburetor, the idling jet is completely cut off during vehicle deceleration, thus resulting in an appreciable saving of fuel.
From the foregoing it will now be seen that there is herein provided an improved antismog carburetor which accomplishes all of the objects of this invention and others, including many advantages of great practical utility and commercial importance.
As various embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.
It is well known that carbon monoxide and other noxious gases are discharged from a motor vehicle engine at a relatively high rate when the foot is removed from the accelerator pedal and the vehicle is decelerated. This, of course, is due to the relatively high degree of vacuum in the intake manifold which causes excessive flow of fuel to the vehicle through the idling nozzle of the carburetor, it being impossible for complete combustion to take place in the absence of sufficient air. This causes a high rate of discharge of carbon monoxide and other noxious gases and tends to cause smogging and substantially pollutes the atmosphere.
SUMMARY OF THE INVENTION
Fuel is admitted from the float chamber of the carburetor both to a carburetor running jet and to an idling jet just beneath the throttle valve. A vertically movable valve stem has a valve at the bottom thereof and is movable downwardly to close communication between the float chamber and the idling nozzle. The valve stem projects upwardly through the float chamber and is provided with a roller at the top thereof engageable by a cam to be normally held open. This cam is connected to the diaphragm of a vacuum motor having a chamber communicating with the intake manifold to be influenced by the degree of vacuum therein. During deceleration of the vehicle with the accelerator pedal released, vacuum in the intake manifold increases to a substantial extend, for example, to 221/2 inches of mercury. Under such conditions, the diaphragm of the vacuum motor moves the cam to drop the valve to closed position. This completely cuts off the admission of fuel to the carburetor through the idling jet and the vehicle engine accordingly acts as a brake. When the vehicle has decelerated to a predetermined extent, there will be a drop in vacuum in the intake manifold, that is, an increase in pressure, in which case the diaphragm returns to normal position and opens the valve referred to to admit fuel through the idling jet, thus preventing motor stalling and providing sufficient fuel for idling.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a sectional view through a carburetor, substantially simplified for the purpose of illustration, parts being shown in elevation;
FIG. 2 is a section on line 2--2 of FIG. 1, and
FIG. 3 is a section on line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the numeral 10 designates a downdraft carburetor as a whole having a mixing passage 12 in the upper end of which is mounted the usual choke valve 14. Passage of air and fuel downwardly through the carburetor is controlled by a conventional throttle 14' mounted on a pivot shaft 16 to which is connected a crank arm 18, the lower end of which is pivotally connected to a rod 20 conventionally leading to the usual accelerator pedal. Depression of such pedal swings the crank arm 18 to a clockwise direction to open the throttle valve 14'.
The carburetor is enlarged at tone side as at 22 to provide a float chamber 24 having a float 26 therein conventionally connected to an inlet valve (not shown) to control the admission of liquid fuel into the float chamber through an intake pipe 30.
The float chamber is provided with an outlet 32 leading in turn to a running jet 34 opening into the mixing passage 12, the passage 32 also being connected to a passage 36 leading to an idling jet 38 opening into the passage 12 just below the adjacent edge of the choke valve 14. The upper end of the passage 36 is provided with a valve seat 40.
A vertically slidable valve 42 is movable downwardly as described below to close the valve seat 40 and thus close the passage 36. Two of the valves 42 and associated elements are employed with a two-barrel carburetor, and the valve 42 in FIG. 1 may be considered to be one of such valves. The two valves for such a carburetor are shown in FIG. 3.
Assuming that the device is used on a two-barrel carburetor, each valve 42 will be provided with an upwardly extending stem 44 tied together as at 46. The stems 44 project upwardly through the cover plate 48 of the float chamber and then inwardly at their upward extremities as at 50 to engage in an axial opening in a roller 52 for which they form supporting shafts.
The roller 52 engages the top of a cam, indicated as a whole by the numeral 54, having a horizontal high portion 56, and the cam slopes downwardly towards it right-hand extremity in FIG. 1 as at 58. The right hand extremity of the cam is flattened as at 60 and slides over a rib 62 formed on the cover 48 of the float chamber.
The cam 54 is provided with a straight shank 64, as shown in FIGS. 1 and 2, and is connected at its extremity to a flexible diaphragm 68 of a vacuum motor 70. The vacuum motor 70 comprises a pair of casing members 72 and 74 in the latter of which is arranged a spring 76 biasing the diaphragm 68 to the right in FIG. 2 and is limited by a stop 78 to normally position the cam surface 56 as shown in FIG. 1. The casing 74 communicates through a nipple 80 with a flexible hose 82, the other end of which is connected to the intake manifold.
OPERATION
As stated, the cam surface 56 is normally positioned as shown in FIG. 1, holding the valves 42 in their upper or open position. Liquid fuel accordingly may flow to both jet nozzles 34 and 38, the latter of which primarily functions when the throttle valve 14' is in idling position. When the vehicle is being driven, the vacuum in the intake manifold will be relatively low and differential pressure acting on opposite sides of the diaphragm 68 will not be sufficient to overcome the loading of the spring 76.
When the vehicle is to be decelerated, the operator will remove his foot from the accelerator pedal in which case the throttle valve 14' moves to the idling position, shown in FIG. 1. Therefore, the relatively high vacuum in the intake manifold, communicating with the lower end of the mixing passage 12, causes too rapid a flow of fuel through the nozzle 38, atmospheric pressure being present above the level of the fuel in the float chamber 24. The relatively high vacuum in the intake manifold communicated to the casing 74 of the vacuum motor 70, will now cause the diaphragm 68 to be subjected to atmospheric pressure at its right side in FIG. 2 and the diaphragm will move against the spring 76 to move the cam 54 to the left in FIG. 1. The sloping portion 58 of the cam will now move beneath the roller 52, permitting this roller to drop together with the stems 44 and valves 42. No liquid fuel accordingly will be admitted to the passage 36 and accordingly the engine will be used as a brake without the admission of fuel to the intake manifold and engine cylinders. It is under such conditions that excess fuel is fed to the engine and lack of air prevents complete combustion of the fuel with the resultant discharge of noxious gases from the engine exhaust pipe. With the present device, no fuel is supplied to the engine, hence there will be no noxious fumes discharged through the exhaust pipe.
When vehicle deceleration has taken place to a predetermined point so that there is a drop of vacuum in the intake manifold below, for example 211/2 inches of mercury, the differential pressures affecting the diaphragm 68 will no longer be sufficient to compress the spring 76, and the latter will move the diaphragm 68 and cam 54 back to its normal position, shown in FIG. 1, whereupon the idling jet 38, or jets in the case of a multibarrel carburetor, will be opened to admit fuel to the passage 12. This prevents the stalling of the engine and restores normal operation of the vehicle engine.
As is well known, an appreciable waste of liquid fuel occurs during deceleration of a vehicle. With regular carburetors, there is a substantial rate of flow of fuel into the mixing passage, which not only results in exhausting noxious fumes, as stated, but performs no useful function. With the present carburetor, the idling jet is completely cut off during vehicle deceleration, thus resulting in an appreciable saving of fuel.
From the foregoing it will now be seen that there is herein provided an improved antismog carburetor which accomplishes all of the objects of this invention and others, including many advantages of great practical utility and commercial importance.
As various embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.