US3570821A

US3570821A - Carburetor

Info

Publication number: US3570821A
Application number: US678967A
Authority: US
Inventors: Brooks Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-10-30
Filing date: 1967-10-30
Publication date: 1971-03-16
Anticipated expiration: 1988-03-16

Abstract

A multibarrel carburetor for an internal combustion engine having an auxiliary carburetor to provide fuel and air to idle, to the intake manifold, when the main throttles are closed at engine-idling speed. The auxiliary carburetor is provided with a throttle valve under the control of a pair of motors and has outlets for conducting idling fuel into a pair of throats of the carburetor. One of the motors is operated by manifold suction, when one of the valves of the carburetor is opened, to open the valve of the auxiliary carburetor. The other motor is operated when the valves of the carburetor are closed and the speed of the engine is above a preselected amount to close the throttle of the auxiliary carburetor.

Description

United States Patent Primary Examiner-Tim R. Miles ABSTRACT: A multibarrel carburetor for an internal combustion engine having an auxiliary carburetor to provide fuel and air to idle, to the intake manifold, when the main throttles are closed at engine-idling speed. The auxiliary carburetor is provided with a throttle valve under the control of a pair of motors and has outlets for conducting idling fuel into a pair of throats of the carburetor. One of the motors is operated by manifold suction, when one of the valves of the carburetor is opened, to open the valve of the auxiliary carburetor. The other motor is operated when the valves of the carburetor are closed and the speed of the engine is above a preselected amount, to close the throttle of the auxiliary carburetor.

caunuuarou The objects of the invention are as stated in the abstract, the mixing of the air and fuel to idle in a very small auxiliary carburetor and dividing such mixed fuel and air to flow into two throats of a multiple throat carburetor.

The use of the suction from the port on the upstream side of the high edge of the butterfly usually used to operate the engine suction-operated spark advance to operate the throttle of the little carburetor to open it automatically when the main throttles are cracked and full manifold suction is developed from said spark advance port.

The use of an engine speed sensor and a throttle closed sensor to control a motor to close the throttle in the little carburetor on closed throttle decelerations above a selected engine speed to reduce total smog-producing elements in the exhaust on such decelerations to provide outside adjustment from the fuel flowing to the little carburetor from the main carburetor bowl for adjustment purposes.

Other objects will be more particularly pointed out in the accompanying specification and claims.

I have illustrated my invention by way of example in the accompanying drawings, in which:

1 16. 1 is a plan view partly cutaway showing one form of the invention.

F16. 2 is a side elevation partly cut away and partly diagrammatic showing the invention shown in FIG. 1.

In these figures I haveshown a four barrel carburetor of conventional design with a smog control for opening the sandwich between the carburetor 9 and the engine 10. The carburetor 9 has two primary barrels 12a and 13a on the lower half (as shown) and two

secondary barrels

20 and 21 in the upper half (as shown). Usually the throttles on the secondary barrels open as the primary throttles are almost open by mechanical and/or spring means of conventional nature not shown here as they are show in US. Pat. No. 2,722,207 to J.O. Sarto, entitled Multiple Stage carburetor, dated Nov. 1955.

Referring to H0. 1 and FIG. 2, thick sandwich 11 has two primary throats 12a and 13a aligned with the primary throats or

barrels

12 and 13 of carburetor 9. These

throats

12 and 13 have throttle valves 17 and 18 mounted on shaft 24 with throttle control arm 25. Link 22 connects arm 25 and unit 23 for controlled motion of throttle butterflies in

throats

21 and 20 by unit 23 as shown in said Sarto reference.

Throttle 30 in small carburetor 35 ismounted on shaft 31 and controlled by arm 32. Suction motor 40, through shaft 41 can move throttle 30 from the idle speed position, possibly as shown, to full open when manifold suction is present in port 42 and lines 43 and 45, andto suction-operated motor 40, as when the edge 18a of throttle 18 moves above port 42 as when substantially above idle operation. This suction from port 42 through tube 450 will also actuate the suction operated spark advance motor 50 to advance breaker plate 52 by arm 51 in the usual manner.

Suction-operated motor 60 is supplied with suction from intake manifold by tube 61 to valve V1 which is open when the throttle is closed, then by line 62 to valve V2 which is open above a predetermined engine speed so that on closed throttle deceleration above a selected engine speed suction will flow from intake manifold 8 past said valves and into line 63 to suction motor 60 to pull rod 64 to the right; as viewed in FIG. 2, to close throttle 30 in small carburetor 35 to shut off the air to idle as well as the fuel to idle. Carburetor 35 feeds air to idle and fuel to idle to the engine through elbow 70 attached to sandwich 11 and then by

passages

71, 73 and 72 to

tubes

74 and 75 in passages 12a and 13a of sandwich 11 respectively. The ends 74a and 750 are turned down toward engine 10 and deliver the air and fuel to idle at high velocity near the center of the primary throats 12a and 13a of sandwich 11. to provide better fiiel and air mixing at idle, and low power cruises at various speeds. Fuel to idle is picked up by tube 80 which may have adjustable needle 81 leading to the orifice near the bottom of the float chamber 9a.

Adjustment screw 84 may adjust the air bleed through port 85 to get the correct rich fuel and air ratio going through tube 86 to valve 87. Valve 87 has adjustable needle valve 88 to adjust the rich fuel and air flow from tube 86 to fuel jet tube 59 above venturi 90. Adjustment screws 91 on

motor

40 and 92 on motor 60 adjust the primary tension on the springs in each motor to provide an adjustment of the idle speed by adjusting the position of throttle 30 in carburetor 35 when idling (and there is no suction in line 45 or line 63) to get the desired warm engine idle speed.

The choke shaft can have

choke valves

101 and 102 mounted thereon and operated by arm 103. Arm 103 is connected by link 104 to bell crank 105. Link 106 connects bell crank to arm 107 that is on shaft 108. Choke valve l09is on shaft 108 so that the motion of choke shaft 100 by rod 110 and thermostat T or manual means (not shown) will choke carburetor 35 by choke valve 109 when shaft 100 is moved to the choke position as whenthe engine 10 is cold to choke the primary throats by choke valves 10] and 102.

In operation when idling the throttles 17 and 18 are closed and usual idle fuel port below the throttles is not needed or shown. The air to idle enters past choke valve 109, picks up fuel from nozzle 89 past venturi 90, past throttle 30 which adjusts the idle speed and is delivered to the intake manifold 8 from primary thioats 12a and 13a in sandwich 11 by curved tubes 74a and 75a respectively for improved mixing of the fuel and air to idle. As the throttles 17 and 18 are opened, suction from port 42 opens valve 30 by motor 40 to help the transition. Further power is provided by opening primary throttles 1.7 and 18 until secondary throttles in the throats above

passages

20 and 21 are opened for full power from all five barrels, including carburetor 35. On deceleration at closed throttle the butterflies in the primary and secondary passages are closed and suction flows through line 63 to motor 60 to close throttle 30 in carburetor 35 to close off such air and fuel from carburetor 35. When the throttles l7 and 18 are opened for power valve V1 will close allowing throttle 30 to open to idle or wider position by suction from port 42 with open throttle 18 which will operate motor 40 to open valve 30 by suction from port 42.

As the throttle is left closed .on a deceleration and the engine speed drops below that sensed by the actuator for valve V2, V2 will close to shut off the suction that closed valve 30 on the deceleration and it will assume the position shown to reestablish engine idle before the engine stalls.

While I have shown this invention applied to a four barrel carburetor, it can also be applied to a multiple barrel carburetor of two or three barrels, or even to a single barrel carburetor where a small carburetor is used for an idle fuel and airmixing device with a throat of about one-half the diameterof either of the main throat diameters for admitting the fuel and air to idle and some of the air and fuel for low speed cruises.

The air that enters the small idling carburetor may be heated by an exhaust or hot water heat exchanger and flow through line 121 to carburetor 35 so as to heat the air to idle much hotter than the air entering the

main throats

12 and 13 at full power operation. This extra heat to the idle carburetor may result in better mixing of the fuel and air, better distribution between cylinders of a 'multicylinder engine on which such multibarrel carburetors are used and still not cut down on the volumetric efficiency and power at full throttle. If the small idle carburetor is used on a single barrel carburetor, the throat and venturi may be still further reduced to have about the same breathing capacity proportionally to the single main throat that it has to the breathing capacity of the two primary throats of the multijet carburetor, as shown. I have illustrated my invention in these various forms; however, many other variations may be possible within the scope of this invention.

Iclaim:

1. A carburetor comprising a plurality of main throats each having a throttle valve therein and an outlet for supplying a combustible mixture to an intake mainfold of an internal combustion engine for idling power, an auxiliary carburetor comprising a throat having a throttle valve therein and an outlet for supplying a combustible mixture to the engine for idling power, conduit means connecting the outlet of the auxiliary carburetor into the outlets of at least a pair of outlets of the main throats adjacent the ends thereof, means for closing the throttle valve of the auxiliary carburetor when the throttle valves in the throats of said at least one pair of outlets are closed and the speed of the engine is Above a predetermined amount, and means for partially opening the throttle valve of the auxiliary carburetor for supplying a mixture for idling power when the throttle valves in the throats of said at least one pair of outlets are closed and the speed of the engine is below said predetermined amount, wherein the means for closing the throttle valve of the auxiliary carburetor comprises a suction-operated motor, conduit means connected to said motor and intake manifold, valve means in said conduit for opening and closing flow of fluid therethrough, and means for opening said valve means when the throttles of said at least one pair of outlets are ,closed and the speed of the engine is above said predetermined amount.

2. A carburetor as defined in claim 1 further including means for fully opening the throttle valve of said auxiliary carburetor when the throttle valves in the throats of said least one pair of outlets are slightly opened.

3. A carburetor as defined in claim 2 wherein said last mentioned means comprises a suction motor, a port extending through the wall of one of said main throats adjacent the upstream side of one of said last-mentioned throttle valves when said throttle valve is closed, and conduit means connecting said port and said last-mentioned suction motor.

4. A carburetor as defined in claim 3 wherein the means for partially opening the throttle valve of the auxiliary carburetor comprises means connecting both suction motors to said lastmentioned valve, and spring means in said motors for urging said last-mentioned valve into the partially opened position.

Claims

1. A carburetor comprising a plurality of main throats each having a throttle valve therein and an outlet for supplying a combustible mixture to an intake mainfold of an internal combustion engine for idling power, an auxiliary carburetor comprising a throat having a throttle valve therein and an outlet for supplying a combustible mixture to the engine for idling power, conduit means connecting the outlet of the auxiliary carburetor into the outlets of at least a pair of outlets of the main throats adjacent the ends thereof, means for closing the throttle valve of the auxiliary carburetor when the throttle valves in the throats of said at least one pair of outlets are closed and the speed of the engine is Above a predetermined amount, and means for partially opening the throttle valve of the auxiliary carburetor for supplying a mixture for idling power when the throttle valves in the throats of said at least one pair of outlets are closed and the speed of the engine is below said predetermined amount, wherein the means for closing the throttle valve of the auxiliary carburetor comprises a suction-operated motor, conduit means connected to said motor and intake manifold, valve means in said conduit for opening and closing flow of fluid therethrough, and means for opening said valve means when the throttles of said at least one pair of outlets are closed and the speed of the engine is above said predetermined amount.

4. A carburetor as defined in claim 3 wherein the means for partially opening the throttle valve of the auxiliary carburetor comprises means connecting both suction motors to said last-mentioned valve, and spring means in said motors for urging said Last-mentioned valve into the partially opened position.