US3739760A

US3739760A - Enrichment fuel-air supply system

Info

Publication number: US3739760A
Application number: US00239063A
Authority: US
Inventors: W Charron
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1972-03-29
Filing date: 1972-03-29
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19
Also published as: JPS5531304B2; CA965663A; JPS497622A; DE2315718A1; GB1361163A

Abstract

An auxiliary fuel-air supply system for an internal combustion engine which supplements the fuel-air supply from the carburetor during engine warmup and acceleration. The response of the system depends upon the engine coolant temperature and the motion and position of the carburetor throttle plate. A valve governs the flow of this supplemental fuel-air mixture into the intake manifold.

Description

[ June 19, 1973 States Patent 1 Charron 3 %1 92 BN4 8 A12 ENRICHMENT FUEL-AIR SUPPLY SYSTEM [75] Inventor:

Hild

William W. Charron, Orchard Lake, Mich.

Hoppew Nakata....

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

Primary ExaminerA1 Lawrence Smith [22] Fled: 1972 Assistant Examiner-Dennis Toth Attorney- Keith L. Zerschling and Roger Erickson Appl. No.: 239,063

.I n P mpmum uW n a m w. mk mnu m nww m i e mP e e Th d m we T mnnm C m fiew. A W mHS R h e T yp h S mr B pwm m A u d Sh e .m m m mo a ww eue fnlmfl mea mnc e T mn m n M mm U r. H Abfie 8 03 G1D3 11mg 3 23 2 9 112N012 rU -l W 3 2 9 1 19 m 15 8 MH J n ,2M 03 2B F21. 1D9 x9e "9 21 1 6 .MZ m n M m mm "e 0 L1 3 CM l 02 .2 C l S Ld .l U F U H 5 55 engine coolant temperature and the motion and posi- 261/DIG. 18, 39 A, 51

tion of the carburetor throttle plate. A valve governs the flow of this supplemental fuel-air mixture into the intake manifold.

[56] References Cited UNITED STATES PATENTS 2,495,485 1/1950 Schwindler 261/51 11 Claims, 3 Drawing Figures Patented June 19, 1973 3 Sheets-Sheet 1 1 ENRICHMENT FUEL-AIR SUPPLY SYSTEM BACKGROUND AND SUMMARY OF THE INVENTION DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An enrichment fuel-air supply system constructed in Increasingly stringent motor vehicle exhaust emission 5 accordance with this invention includes three principal regulations, coupled with performance and economy requirements, impose difficult demands on todays internal combustion engine components, particularly carburetors. Special problems are encountered during engine warmup. Historically, the solution was to generously enrichen the air-fuel mixture to compensate for the retarding effect that colder than normal operating temperatures have upon fuel vaporization. Such enrichment was simply provided with a conventional choke plate often linked to a thermo-sensitive bimetal springv Under anticipated vehicle exhaust emissions regulations, fueLair mixture enrichment sufficient to initiate and maintain engine combustion in a cold climate may not be achievable with a choke device such as described.

This invention provides apparatus for enriching the combustible mixture under cold starting and engine warmup conditions that is more precisely controllable than the traditional thermostatically controlled choke plate. The invention also provides a response of a measured or limited time duration to transient engine conditions such as acceleration. Furthermore, the invention provides an enrichment fuel-air supply system which is auxiliary or supplementary to the traditional engine carburetor.

An enrichment fuel-air supply system that supple ments the carburetor of an internal combustion engine constructed in accordance with this invention includes a passage or chamber which receives fuel and air for producing a combustible mixture. A valve having a movable member regulates the flow of fuel and air into the passage or chamber. The fuel-air mixture is discharged from the chamber into the intake manifold independently of the engine carburetor. A linkage interconnects the movable member of the valve to a lever displaceable with the carburetor throttle plate. The linkage includes a time delay mechanism which upon actuation of the throttle lever in one direction acts similarly to a solid link and then incrementally lengthens the linkage as a function of time permitting thevalve member controlling entrance of enrichment fuel and air to return to its preactuation position without the necessity of return movement of the throttle lever and plate to its preactuation position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross sectional view of an enrichment fuelair supply system constructed in accordance with the invention showing the relationship of the system elements in a cold, idling engine. The phantom lines represent the position of the elements immediately following an acceleration;

FIG. 2 is a cross sectional view of the enrichment fuel-air supply system showing the relationship of the system elements in a partially warmed, idling engine. The phantom lines represent the position of the elements immediately following an acceleration;

FIG. 3 of the drawing is a cross sectional view of the enrichment fuel-air supply system showing a relationship of the elements in a fully warmed idling engine. The phantom lines represent the position of the elements immediately following an acceleration.

components. The first is a valve assembly 1 l which regulates flow of enrichment fuel and air to the intake manifold 13. The second is a time delay linkage assembly l5 interconnecting the valve assembly and the carburetor throttle lever 17. The linkage assembly includes a dual diaphragm vacuum decay device 19 which acts similar to a solid link upon throttle advance and which progressively lengthens following throttle actuation to release linkage tension, thereby permitting the movable elements of the valve assembly 11 to return to their preactuation positions. The third principal component is a thermostatically controlled valve element abutment assembly 21 responsive to coolant temperatures within the engine block 23. With the exception of the throttle plate 25 and throttle lever 17 pivotally mounted to carburetor housing 27 all of the above components and elements are auxiliary or external to the components of a conventional internal combustion carburetor.

The valve assembly 11 includes a housing 29 in which two calibrated orifices 31 and 33 are formed. Fuel enters the housing through inlet 35 and passes through the orifice 31 into a first passage or chamber portion 37 where it is mixed with air entering into the chamber from inlet 39. The mixture passes through orifice 33 into a second passage or chamber portion 41 where it is further mixed and conducted into the intake manifold 13 through conduit 43. A movable valve element 45 is received within the housing and has upper and lower

tapered portions

47 and 49 which cooperate with orifices 31 and 33, respectively, to vary the restriction or effective openings thereof.

Valve portions

47 and 49 are relatively adjustable by means of a threaded connection 50. The movable valve element 45 has an end portion 51 extending downwardly from the lower tapered portion 49 which is engageable with lever 53 of abutment assembly 21. The lever 53 is pivotally mounted to the housing 29 and pin joined to movable piston element 55 of the thermostat 57. The upper end 59 of the movable valve element 45 is engageable with a portion 61 of the housing to form an abutment limiting the upward travel of the movable valve element and defining a maximum opening for orifices 31 and 33.

The linkage assembly 15 includes in addition to the dual diaphragm vacuum decay device 19, a motion transfer lever 63 pivotally connected to housing 29 and a tension spring 65. The lever 63 interconnects the vac- .uum decay device 19 and the movable valve element 45. The spring 65 interconnects the throttle lever 17 and the valve element 45.

The dual diaphragm vacuum decay device 19 includes an outer housing 67 having two flexible diaphragms 69 and 71 extending across its major diameter and forming a pneumatic chamber 73. A rod 75 is connected to diaphragm '69 and is joined at its protruding end to lever 63 with a pin-and-slot connection. Rod 75 is biased by compression spring 79 toward a maximum protracted position or leftwardly as viewed in FIG. 1. An oppositely directed rod 77 is connected to diaphragm 71 and is joined at its protruding end to spring 65. Rod 77 includes a check valve assembly 81 which closes a passage to the pneumatic chamber-73 when the chamber is under tension, as during opening of throttle plate 25. The check valve assembly opens when the chamber is under compression between the

armatures

75 and 77, as during throttle closing, to permit a rapid reduction in chamber volume. A small bleed hole 83 continuously vents the chamber 73 to the atmosphere and permits a controlled passage of air. The vent provides the vacuum decay function of the device 19, which will be explained later in greater detail.

The thermostatic abutment assembly 21 includes a conventional thermostat assembly 57 mounted within a wall 87 of the engine block 23. The thermostat includes a movable piston element 55 which increasingly extends or protrudes from the remainder of the thermostat as the temperature of the coolant within the engine block rises. The movable thermostat element is biased by spring 91 toward a retracted or minimum extending position. The movable piston element is pinjoined to lever assembly 53, a portion of which provides an abutment for the end 51 of the movable valve element 45. When the engine is cold the thermostat element 55 is fully protracted and the abutment of lever assembly 53 is in its uppermost position.

OPERATION The enrichment fuel-air supply system described above functions to supplement or replace the choke system, the fast idling system and/or the power valve system of a typical internal combustion engine carburetor so that vehicle emissions are more precisely controllable.

During engine idle and under a partially warmed coolant temperature, the flexible diaphragm 69 is positioned as shown by solid lines in FIG. 2 of the drawings.

Diaphragm 71 is in the unloaded or unstressed position also shown by solid lines in FIG. 2.

When the throttle plate is opened to the position shown in phantom lines designated 25', the flexible diaphragm 71 moves rightwardly to the position 71'. Upon initial rightward displacement of diaphragm 71, the check valve 81 closes and chamber 73 is substantially sealed (except for air bleed hole 83). A partial vacuum is created within chamber 73 causing atmospheric pressure to displace diaphragm 69 rightwardly to the position 69 and to lift the valve assembly 45 to a less restricted position shown in phantom as 45'. The decrease in restriction causes increased fuel and air flow through conduit 43 to enrichen the overall combustible mixture being delivered to the combustion chambers. Immediately following throttle opening when the system elements have assumed the positions shown in phantom in FIG. 2, the vacuum decay device 19 is under tension between

springs

65 and 79. Air bleeds into chamber 73 through passage 83 to relieve the partial vacuum until diaphragm 69 and valve assembly 45 have assumed their preactuation positions as shown by their solid line representations in FIG. 2. The air bleed passage 83 is calibrated to give a desired vacuum decay period. When the throttle blade 25 is once again closed, the check valve 81 opens to permit relatively unrestricted collapse of the chamber 73 as diaphragm 71 returns from its phantom line position 71 to its preactuation position shown by the solid line representation. A lightweight spring (not shown) may be provided to assist the return diaphragm 71 and rod 77 to its preactuation position.

Prior to the throttle actuation described in the preceding paragraph, enrichment fuel was being provided to intake manifold 13 during engine warmup to supplement that provided by the carburetor 27. Immediately following throttle actuation the enrichment flow through conduit 43 is increased by the change in position of valve 45 to supplement or replace the accelerator pump and/or power valve systems of the conventional carburetor. The valve then slowly returns to its preactuation position even though the throttle plate retains its open position 25.

FIG. 3 of the drawings shows the relationship of the system elements during engine idle when the coolant within block 23 is fully warmed. The thermostat piston 55 is fully protracted and the valve assembly 45 is in its lowermost position with the orifices 31 and 33 fully restricted. No enrichment fuel or a minimum of fuel is being provided to supplement the carburetor. Upon throttle actuation from the closed position to the open position 25 shown in FIG. 3, the system functions as described previously with reference to FIG. 2 and the system elements assume the phantom line positions designated 71, 69' and 45. Enrichment fuel is then provided to intake manifold 13 through conduit 43 to supplement that provided by the carburetor. Chamber 73 is under tension and enlarges as air is bled through passage 83 to relieve the partial vacuum therein until the valve assembly 45 again reaches its preactuation, closed (solid line) position.

FIG. 1 of the drawings shows the relationship of the system elements during engine idle when the coolant within block 23 is cold. The thermostat piston 55 is fully retracted and valve assembly 45 is fully raised by abutment lever 53 resulting in maximum fuel and air flow through orifices 31 and 33. Opening the throttle plate 25 to position 25 results in a very limited movement of the diaphragm 69 and 71 to position 69 and 71', respectively, because the valve assembly 45 at idle is in its fully raised position engaging abutment 71. Thus, when the engine is cold the enrichment fuel system provides maximum enrichment at idle and during acceleration.

Modifications and alterations will occur to those skilled in the art which are included within the scope of the following claims.

I claim:

1. In an internal combustion engine including:

a carburetor having a pivotable throttle plate and a lever displaceable with the throttle plate,

an intake manifold,

a source of fuel,

a source of air,

an enrichment fuel-air supply system supplementary to said carburetor, chamber means receiving said fuel and air for intermixing therein,

valve means having a movable member regulating flow of fuel and air from said sources to said chamber means,

conduit means interconnecting said chamber means and said intake manifold,

linkage means interconnecting the movable element of said valve means to the lever displaceable with said throttle plate,

said linkage means including a time delay mechanism which upon opening actuation of the throttle lever acts similarly to a solid link and which following actuation incrementally lengthens as a function of time permitting the movable valve element to return to its prior position without return movement of the throttle lever and plate to its position prior to the opening actuation.

2. In an internal combustion engine including:

an intake manifold,

a source of fuel,

a source of air,

an enrichment fuel-air supply system supplementary to said carburetor,

chamber means receiving fuel and air for intermixing therein,

valve means having an element movable to increase and decrease flow of fuel and air from said sources to said chamber means,

conduit means interconnecting said chamber means and said intake manifold,

said linkage means including a vacuum decay component which progressively lengthens following throttle opening actuation to return the movable member of said valve means to its preactuation position.

3. An enrichment fuel-air supply system'according to claim 2,

said vacuum decay component including a housing,

a pair of movable elements forming a variable volume substantially sealed air chamber within the housing,

check valve means closeable to prevent entry of air into said chamber and openable to permit escape of air from said chamber,

an air bleed passage from the atmosphere to said chamber permitting limited entry of air into said chamber when the pressure within the chamber is less than atmospheric.

4. An enrichment fuel-air supply system according to claim 2,

means to vary the position of the movable element of said valve means in response to changes in engine temperature.

5. An enrichment fuel-air supply system according to claim 3,

means to vary the position of the movable element of I said valve means in response to changes in engine temperature.

6. An enrichment fuel-air supply system according to claim 2,

a thermostat sensing the coolant temperature of the engine,

said thermostat including an element movable in response to changes in coolant temperatures,

variable position abutment means limiting the range of displacement of the movable element of said valve means,

said abutment means being connected to said movable thermostat element.

7. An enrichment fuel-air supply system according to claim 3,

a thermostat sensing the coolant temperature of the engine,

said abutment means being connected to said movable thermostat element.

8. An enrichment fuel-air supply system according to claim 2,

said vacuum decay component including a housing,

a pair of flexible diaphragms forming a variable volume substantially sealed air chamber within said housing,

first rod means secured to one of said diaphragms extending in a given direction,

second rod means secured to the other of said diaphragm extending in the opposite direction,

said vacuum decay component connected to the remainder of said linkage means by said rod means,

a check valve being closeable to prevent entry of atmospheric air into said chamber and openable to permit escape of compressed air from said chamber,

an air bleed passage from the atmosphere to said chamber permitted limited and controlled entry of air into said chamber when the pressure within said chamber is less than atmospheric.

9. An enrichment fuel-air supply system according to claim 4,

said vacuum decay component including a housing,

an air'bleed passage from the atmosphere to said chamber permitted limited and controlled entry of air into said chamber when the pressure within said chamber is less than atmospheric.

10. An enrichment fuel-air supply system according to claim 6,

said vacuum decay component including a housing,

acheck valve being closeable to prevent entry of atmospheric air into said chamber and openable to permit escape of compressed air from said chamber,

3,739,760 7 8 an air bleed passage from the atmosphere to said 11. An enrichment fuel-air supply system according chamber permitted limited and controlled entry of to claim 10, said linkage means including a spring loadair into said chamber when the pressure within said able in tension. chamber is less than atmospheric.

Claims

1. In an internal combustion engine including: a carburetor having a pivotable throttle plate and a lever displaceable with the throttle plate, an intake manifold, a source of fuel, a source of air, an enrichment fuel-air supply system supplementary to said carburetor, chamber means receiving said fuel and air for intermixing therein, valve means having a movable member regulating flow of fuel and air from said sources to said chamber means, conduit means interconnecting said chamber means and said intake manifold, linkage means interconnecting the movable element of said valve means to the lever displaceable with said throttle plate, said linkage means including a time delay mechanism which upon opening actuation of the throttle lever acts similarly to a solid link and which following actuation incrementally lengthens as a function of time permitting the movable valve element to return to its prior position without return movement of the throttle lever and plate to its position prior to the opening actuation.

2. In an internal combustion engine including: a carburetor having a pivotable throttle plate and a lever displaceable with the throttle plate, an intake manifold, a source of fuel, a source of air, an enrichment fuel-air supply system supplementary to said carburetor, chamber means receiving fuel and air for intermixing therein, valve means having an element movable to increase and decrease flow of fuel and air from said sources to said chamber means, conduit means interconnecting said chamber means and said intake manifold, linkage means interconnecting the movable element of said valve means to the lever displaceable with said throttle plate, said linkage means including a vacuum decay component which progressively lengthens following throttle opening actuation to return the movable member of said valve means to its preactuation position.

3. An enrichment fuel-air supply system according to claim 2, said vacuum decay component including a housing, a pair of movable elements forming a variable volume substantially sealed air chamber within the housing, check valve means closeable to prevent entry of air into said chamber and openable to permit escape of air from said chamber, an air bleed passage from the atmosphere to said chamber permitting limited entry of air into said chamber when the pressure within the chamber is less than atmospheric.

4. An enrichment fuel-air supply system according to claim 2, means to vary the position of the movable element of said valve means in response to changes in engine temperature.

5. An enrichment fuel-air supply system according to claim 3, means to vary the position of the movable element of said valve means in response to changes in engine temperature.

6. An enrichment fuel-air supply system according to claim 2, a thermostat sensing the coolant temperature of the engine, said thermostat including an element movable in response to changes in coolant temperatures, variable position abutment means limiting the range of displacement of the movable element of said valve means, said abutment means being connected to said movable thermostat element.

7. An enrichment fuel-air supply system according to claim 3, a thermostat sensing the coolant temperature of the engine, said thermostat including an element movable in response to changes in coolant temperatures, variable position abutment means limiting the range of displacement of the movable element of said valve means, said abutment means being connected to said movable thermostat element.

8. An enrichment fuel-air supply system according to claim 2, said vacuum decay component including a housing, a pair of flexible diaphragms forming a variable volume substantially sealed air chamber within said housing, first rod means secured to one of said diaphragms extending in a given direction, second rod means secured to the other of said diaphragm extending in the opposite direction, said vacuum decay component connected to the remainder of said linkage means by said rod means, a check valve being closeable to prevent entry of atmospheric air into said chamber and openable to permit escape of compressed air from said chamber, an air bleed passage from the atmosphere to said chamber permitted limited and controlled entry of air into said chamber when the pressure within said chamber is less than atmospheric.

9. An enrichment fuel-air supply system according to claim 4, said vacuum decay component including a housing, a pair of flexible diaphragms forming a variable volume substantially sealed air chamber within said housing, first rod means secured to one of said diaphragms extending in a given direction, second rod means secured to the other of said diaphragm extending in the opposite direction, said vacuum decay component connected to the remainder of said linkage means by said rod means, a check valve being closeable to prevent entry of atmospheric air into said chamber and openable to permit escape of compressed air from said chamber, an air bleed passage from the atmosphere to said chamber permitted limited and controlled entry of air into said chamber when the pressure within said chamber is less than atmospheric.

10. An enrichment fuel-air supply system according to claim 6, said vacuum decay component including a housing, a pair of flexible diaphragms forming a variable volume substantially sealed air chamber within said housing, first rod means secured to one of said diaphragms extending in a given direction, second rod means secured to the other of said diaphragm extending in the opposite direction, said vacuum decay component connected to the remainder of said linkage means by said rod means, a check valve being closeable to prevent entry of atmospheric air into said chamber and openable to permit escape of compressed air from said chamber, an air bleed passage from the atmosphere to said chamber permitted limited and controlled entry of air into said chamber when the pressure within said chamber is less than atmospheric.

11. An enrichment fuel-air supply system according to claim 10, said linkage means including a spring loadable in tension.