US3823699A

US3823699A - Deceleration fuel flow and emission control for internal combustion engines

Info

Publication number: US3823699A
Application number: US00299460A
Authority: US
Inventors: P Adair
Original assignee: Aerodex Inc
Current assignee: Aerodex Inc
Priority date: 1972-10-20
Filing date: 1972-10-20
Publication date: 1974-07-16
Anticipated expiration: 1991-07-16

Abstract

A control for the idling carbureted mixture of fuel and air of a vehicle-propelling internal combustion engine to reduce the fuel to air ratio when the vehicle is decelerating and is coupled to the engine. Engine intake manifold pressure and throttle valve setting govern the control which preferably leans the mixture sufficiently so it is not combustible in the engine.

Description

Adair DECELERATION FUEL FLOW AND EMISSION CONTROL FOR INTERNAL 1111 3,823,699 1451 July 16, 1974 FOREIGN PATENTS OR APPLICATIONS 223,758 10/1924 Great Britain.. l23/l 19 DB COMBUSTION ENGINES 1,217,948 1/1971 Great Britain 123/97 B Inventor: Paul F. Adair Miami France B 1,179,765 3/1961 Germany 23/97 B [73] Assignee: Aerodex, Incorporated, M1am1, Fla. I

[22] Filed: Oct. 20, 1972 Primary Examiner-Wendell E.-Burns' [211 pp No: 299,460 Attorney, Agent, 0r FtrmCushman, Darby &

Cushman 1 [52] US. Cl 123/119 DB, 123/97 B, 123/124 R 4 I 51 1111.01. F02m 23/04 [571 AB a Field of arch l23/97 B, 124 R, 119 DB A control for the idling carbureted mixture of fuel and r air of a vehicle propelling internal combustion engine References Clted to reduce the fuel to air ratio when the vehicle is de- UNITED STATES PATENTS celerating and is coupled to the engine. Engine intake 2 439 57 4/19 Mallory 123/97 B manifold pressure and throttle valve setting govern the 2:443:562 6/1948 Hilger et al. .L 123/97 B Centre! which Preferably leans the mixture sufficiently 2,453,125 ll/l948 Flint 123/97 B so it is not combustible in the engine, 2,957,463 lO/l960 Schnabel 123/97 B 3,677,526 7/1972 Perlot 125/97 B 4 l 2 Drawmg Flgms 0 Z 4/ L I4 7 2 r32 K I $0 W T 'm 62 5 #5 ill ll. .2 Z //fi f6 54 11% //Z A /fl/ 65 w aa 54/ a2 DECELERATION FUEL FLOW AND EMISSION CONTROL FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION This invention relates to an arrangement for reducing the normal fuel to air ratio of the idle carbureted mixture of a vehicle-propelling internal combustion engine during deceleration of the vehicle when it is coupled to, and to some extent driving, the engine. More especially, this invention relates to an improved arrangement of the foregoing type for reducing the idle fuel to air ratio in-response to predetermined negative intake manifold pressure. By negative pressure is meant pressure below atmospheric.

During normal operation of a conventional automobile propelled by an internal combustion engine, the engine intake manifold vacuum, when the engine is idling with no appreciable load, will be around 19 inches of mercury. When the engine is driving the vehicle the manifold. vacuum will vary between and 19 inches of mercury, i.e., between about 19 inches when the engine is idling to about 0 inches when the engine is in fast acceleration. When the vehicle is rapidly decelerated, however, and the engine remains connected to the driving wheels so that the engine is being driven to some extent by the vehicle, the manifold vacuum may rise to as much as 21 to 28 inches of mercury, depending upon the speed of the vehicle and the rate of deceleration.

During such deceleration, the higher manifold vacuum draws an above normal amount of the fuel air mixture through the idling duct into the engine. The abnorma] amount of fuel being thus used during deceleration is wasted. Moreover, since the engine is developing power from the fuel and air mixture being drawn thereinto through the idle jet by the higher manifold vacuum, the engine is not being used to its full capacity to retard or brake the vehicle, so that the vehicle brakes must be usedto an unnecessary extent to decelerate the vehicle.

Accordingly, it is an object of this invention to provide an improved arrangement which will greatly reduce the fuel to air ratio, preferably below that necessary to support combustion, of the idle fuel and air mixture of a vehicle-impelling internal combustion engine during deceleration of the vehicle when the vehicle wheels are connected to the engine.

It is another object of this invention to provide an improved arrangement of the foregoing type which will reduce fuel consumption, will decrease exhaust and smoke emissions, and will decrease brake wear of a vehicle driven by an internal combustion engine.

It is another object of this invention to provide an improved arrangement of the type described that is readily adapted to be attached to a conventional internal combustion engine which drives a conventional vehicle.

Other objects and advantages of the invention will become apparent from the following description and accompanying drawing.

DESCRIPTION or THE DRAWING FIG. 1 is a schematic fragmentary sectional view showing the application of this invention to a conventional internal combustion engine.

FIG.2 is an enlarged fragmentary view of a portion of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawing, there is shown a conventional downflow carburetor barrel 10 for conduct- 7 ing a carbureted mixture of fuel, usually gasoline, and

-20 of the idle duct 18 is controlled by .an adjustable needle valve (not shown).

In the application of this invention to a standard type carburetor, as above described, the conventional idle needle valve is replaced by an adjustable needle valve 22 of substantially the same construction but having a longitudinal duct 24 therein open at its outer end and terminating at its inner end in one or more radial orifices 26 which open into the idle duct 18 upstream of the outlet port 20. A conduit 28, e.g., a flexible hose,

has one end thereof connected to the outer end of the needle valve 22, in communication with itsduct 24, and the other end connected to a valve device 30. The latter 30 is arranged to communicate the needle valve duct 24, and consequently the idle duct 18, with the atmosphere to thus greatly decrease the fuel to air ratio of the idle mixture admitted to the engine manifold 12 under certain conditions. Preferably this ratio is decreased to such an extent that the mixture will not support combustion. The valve device 30 is arranged to be responsive to both manifold pressure and the position of the throttle valve 14 in such a way that when the throttle valve is closed and the manifold vacuum exceeds a predetermined amount, such as normal idle manifold vacuum, the idle duct 18 is in communication with the atmosphere and the idle mixture is leaned as aforesaid.

The valve device 30includes a housing 32, preferably in two

parts

34 and 36, having an interior valve chamber 38 provided with one or more air inlet ports 40, in the housing part 34, communicating with ,the atmosphere. The chamber 38 also is provided with at least one outlet port 42 in the housing part 34 having a valve seat 44 at its inner end normally closed by a valve disc 46 guided for reciprocation by a pin 48 coaxially fixed thereto and sliding in a bore 50 in the housing part 34. The outer end of the outlet port 42 is provided with an appropriate fitting 52 to which the conduit 28 is connected. It will be seen that when the disc 46 is unseated the inlet ports 40 are in unobstructed communication with the outlet port 42.

The valve disc 46 is normally urged against its seat 44 by a coil compression spring 54 interposed between a nut 56, threaded onto a central stud 58 on the disc opposite the pin 48, and an enlarged inner head 60 on an adjustment screw 62 engaged in and extending through a tapped opening 64 in the wall of the housing part 36. The screw 62 is sealed to the housing part36 by an O- ring 66 disposed in a circumferential groove in the enlarged head 60 and engaged with the smooth wall of an interior cylindrical countersink 68 for the opening 64.

A lock nut 70 preferably is threaded onto the outer end of the screw 62.

The housing 32 also is provided with an interior pressure chamber 72 having a common wall with the valve chamber 38 formed by a pressure responsive diaphragm 74. The central portion of the diaphragm 74 is clamped in sealing engagement with the rear of the valve disc 46 by an enlarged washer 76 beneath the nut 56, while the periphery of the disphragm is clamped between the two

parts

34 and 36 of the valve housing 32.

The pressure chamber 72 is connected to the engine intake manifold 12 by a conduit 78, e.g., a flexible hose, having one end thereof connected to an appropriate fitting 80 on the intake manifold and the other end thereof connected toxa fitting 82 on the valve housing part 36. The fitting 82 communicates with a housing port 84 provided, on its inner end, with a valve seat 86 normally engaged by the pointed end of a cylindrical valve member 88 reciprocal in a'housing bore 90. The valve member 88 is provided with a plurality of longitudinal grooves 92, terminating at their rearward end at a reduced extension 94 providing an annular space 96 communicating at all times with a port 98 opening to the pressure chamber 72. The other end of the housing bore 90 communicates with atmosphere by a reduced bore 100 in the housing part 34 and an aligned opening 102 in the periphery of the diaphragm 74. When the valve member 88 is seated against its seat 86, pressure chamber 72 communicates with atmosphere via port 98, annular space 96, opening 102, and bore 100. The communication is interrupted, however, when valve member 88 is pulled off its seat 86 and its rear end seats against the marginal edges of the diaphragm 74 surrounding the opening 102.

The arrangement is such that the manifold vacuum normally retains the valve member 88 seated against its seat 86. If the valve member 88 is moved off its seat 86, however, as later descirbed, the manifold vacuum will be communicated to the pressure chamber 72. via the conduit 78, the port 84, the longitudinal grooves 92, the annular space 96, and'the port 98. At the same time the rear end of the valve member 88 seats against the marginal edges of the diaphragm 74 about the opening 102 to seal off the space 96 from atmosphere. When, as aforesaid, such vacuum exceeds a predetermined amount, normally 19 inches of mercury, atmospheric pressure in the valve chamber 38 will move the diaphragm 74 toward the pressure chamber 72 against the action of the spring 54 and unseat the valve disc 46. Manifestly, the spring force can be adjusted, by the screw 62, to enable the valve disc 46 to be unseated by any selected predetermined manifold vacuum.

The valve member 88 is connected to the throttle valve 14 by any appropriate mechanical arrangement, such as a wire or nyloncord 104 having one end connected to the rear end of the valve member 88 and the other end to a lever 106 on'an outer end of the throttle valve shaft 16. The arrangement is such that when the throttle valve I4 is closed (open is'shown in the drawings) the lever 106 and wire or nylon cord 104 pull the valve member 88 off its seat 86 and against the marginal edges of the diaphragm 74 about the opening 102, and so communicates the manifold vacuum with the pressure chamber 72. In the event that the vehicle driven by the engine decelerates, with the throttle valve 14 closed, to such an extent as to increase the manifold vacuum above a normal idle vacuum, e.g. about 19 inches of mercury, the valve disc 46'will unseat and thus communicate the carburetor idle duct 18 with the atmosphere at a location slightly upstream of the idle duct outlet port 20. This communication will, of course,greatly decrease the fuel to air ratio of the mixture being drawninto the engine manifold 12 through the idle duct 18. Preferably the ratio is reduced to the extent that the mixture will not be combustible in the engine. This will, in turn, decrease the fuel consumption of the engine and consequently reduce exhaust and smoke emissions therefrom during such deceleration. Further, since the fuel supply to the engine will be reduced the power developed by the engine will also be reduced and preferably none developed, so the engine will have greater drag resistance to slow the vehicle. Such greater engine drag resistance will result in less necessity for application of the vehicle brakes and thus decrease wear on the latter.

It readily will be seen that the foregoing arrangement can be manufactured in separate components for application to conventional internal combustion engines of conventional vehicles. The pressure responsive valve device 30 can be constructed as a single unit, while the usual idle needle valve of the carburetor need only be replaced by the tubular needle valve 22 illustrated in the drawings. The only other modification necessary is that of providing a fitting in the engine intake manifold 12 for connection of the conduit 78. Frequently, however, a suitable fitting already is installed on engine intake manifolds of conventional automobiles.

- Instead of replacing the standard idling needle valve of the carburetor with the tubular needle valve 22 shown in the drawings, the carburetor could be modified by tapping into the idle duct 18 at location above the needle valve and providing a fixture 118, as shown in dotted lines, at this point for connection of the conduit 28. Further, in the event that the carburetor has more than one barrel, the valve chamber 38 can be provided with another outlet port 110 terminating inan inner seat engageable by the valve disc 46, and such port can be provided with a fixture 112 for connection of another conduit thereto to be connecected to the other barrel of the carburetor in exactly the same manner as illustrated for the barrel 10. It further will be realized that the entire arrangement can be manufactured integrally with a carburetor, instead of being manufactured as an attachment. There are some carburetor designs wherein the idle discharge port 20 is a fixed orifice and idle mixture is changed by an adjustable air bleed into idle duct 18. Attachment of valve device 30 to a carburetor of this type and use of the hollow special design adjustable needle valve 22 will work in the same manner for this type carburetor as for the one illustrated in FIG. 1.

It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the specific embodiment shown and described is susceptible to modification without What is claimed is: '7 V A g I 1. In a vehicle-propelling internal combustion engine having a duct for admitting a carbureted mixture of air and fuel toan intake manifold, a throttle valve in said duct, and an idle duct by-passing said valve, the combination of an idle mixture control comprising:

self-contained separate component means connected by passageway means to said manifold and to said idle duct and including means responsive to a predetermined negative pressure in said manifold for communicating said idle duct with the atmosphere to decrease the flow of fuel therethrough and therefor decrease the ratio of fuel to air in the mixture admitted therefrom to said manifold and valve means controlling communication between said responsive means and said manifold; and mechanical means connected to said valve means and to said throttle valve for opening said valve means when said throttle valve is closed.

2. The control defined in claim 1 including an adjustable needle valve controlling the outlet of the idle duct, said needle valve having a duct therein terminating in an outlet upstream of said ilde duct outlet, and conduit means communicating said needle valve duct with the pressure responsive means.

3. The control defined in claim 1 in which the pressure responsive means includes valve means, adjustable means urging'said valve means to closed position, and diaphragm means having one side thereof exposed to atmospheric pressure and the other side thereof exposable to manifold pressure for urging said valve means to open position.

4. The control defined in claim 1 in which the ratio of fuel to air in the mixture admitted from the idle duct is descreased to the extent where the mixture is not ge u tib s in h is s-v

Claims

1. In a vehicle-propelling internal combustion engine having a duct for admitting a carbureted mixture of air and fuel to an intake manifold, a throttle valve in said duct, and an idle duct by-passing said valve, the combination of an idle mixture control comprising: self-contained separate component means connected by passageway means to said manifold and to said idle duct and including means responsive to a predetermined negative pressure in said manifold for communicating said idle duct with the atmosphere to decrease the flow of fuel therethrough and therefor decrease the ratio of fuel to air in the mixture admitted therefrom to said manifold and valve means controlling communication between said responsive means and said manifold; and mechanical means connected to said valve means and to said throttle valve for opening said valve means when said throttle valve is closed.

3. The control defined in claim 1 in which the pressure responsive means includes valve means, adjustable means urging said valve means to closed position, and diaphragm means having one side thereof exposed to atmospheric pressure and The other side thereof exposable to manifold pressure for urging said valve means to open position.

4. The control defined in claim 1 in which the ratio of fuel to air in the mixture admitted from the idle duct is descreased to the extent where the mixture is not combustible in the engine.