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Carburetor with fuel shut-off means having a fuel-air ratio adjustment mechanism
US3669083A
United States
- Inventor
Edward F Fort - Current Assignee
- Navistar International Corp
Worldwide applications
1970
US
Application US55804A events
1972-06-13
Application granted
1972-06-13
1989-06-13
Anticipated expiration
Status
Expired - Lifetime
Description
translated from
waited States Patent Fort 51 June 13, 1972 [54] CARBURETOR WITH FUEL SHUT-OFF MEANS HAVING A FUEL-AIR RATIO ADJUSTMENT MECHANISM I [72] Inventor: Edward F. Fort, Naperville, Ill.
[73] Assignee: International Harvester Company, Chicago, Ill.
22 Filed: July17, 1970 21 Appl.No.: 55,804
[52] U.S.Cl "123/97 13, 123/119 D, 123/1 19 DB,
26l/DIG. 19 51 Int. Cl .rozu 9/00, F02n 7/12 58 FieldofSearch ..l23/97B, 119D, 119 DB; 26l/DlG. 19
[5v6] References Cited UNITED STATES PATENTS 3,447,516 6/1969 Bartholomew 123/97 B 2,036,205 4/1936 Ericson ..l23/97 B Primary Examiner-Wendell E. Burns Attomey-Floyd B. Harman [57] ABSTRACT In a carburetor construction for metering liquid fuel for delivery downstream of the throttle valve to a spark-ignition engine, means are provided for remotely controlling the fuelto-air ratio including a rapidly operative mechanism for shutting off the fuel source during periods when the engine or vehicle is decelerating toward a predetermined minimum speed value.
12 Claims, 4 Drawing Figures 40 70 EN G/NE CARBURETOR WITH FUEL SHUT-OFF MEANS HAVING A FUEL-AIR RATIO ADJUSTMENT MECHANISM BACKGROUND OF THE INVENTION This invention relates to a liquid fuel metering system for a spark-ignition internal combustion engine. More in particular this invention relates to a carburetor construction employing a fluidic device for'metering liquid fuel for delivery through nozzle means positioned downstream of the throttle control valve wherein the system singularly is capable of supplying fuel to the engine at a substantially constant fuel-air ratio under normal operating conditions for all loads imposed upon the engine and yet permit the engine to idle under the-same system. However, this invention is principally directed to altering, in a favorable direction, the fuel-air ratio delivered when the engine is under abnormal operating conditions and is an improvement upon the carburetor construction described in copending application Ser. No. 806,645 filed on Mar. 12, 1969, now US. Pat. No..3,544,082 and assigned to the same assignee herein, reference there to being had.
A striking advantage of the present invention is that when a vehicle is decelerating with the engine under closed or nearly closed throttle condition, the 'fuel supply to the engine is completely shut-off but provision is made for smooth restart automatically without attention of the operator. Thus hydrocarbons and products of fuel combustion discharged into the atmosphere during such decelerating periods attendant thereto are eliminated with a corresponding fuel consumption improvement in efficiency. Further, since combustion during decelerating periods'is eliminated the engine functions in a manner similar to an air pump which may effectively be utilized in assisting the braking of the vehicle. This is an important feature because there is a considerable difference between the braking drag of an engine wherein the fuel supply is cut-off as compared with the braking drag of an engine wherein fuel is fed to the engine at idling rate for in the latter case there is combustiontakingplace thus obviously providing some power which appreciably subtracts from the engines braking drag.
SUMMARY OF THE INVENTION An important object of the present invention is to provide a fuel shut-off mechanism in a carburetor which is effective during periods when the associated engine or vehicle is decelerating or when such engine is utilized as a brake upon its load.
Another object of the invention is to provide a fuel shut-off mechanism according to the preceding object wherein the device functions to cut off all fuel supply to the engine automatically when the absolute pressure differential between atmospheric pressure and the pressure downstream of the throttle valve exceeds a predetermined limit.
Still another object of the invention is to provide a fuel shutoff mechanism according to the preceding objects wherein the device is precluded from functioning to cut off fuel supply to the engine when the vehicle speed is below a predetermined value.
Yet a further object of the invention is to provide a fuel shut-off mechanism according to the preceding objects wherein the device is externally adjustable for controlling the fuel-to-air ratio delivered to the engine during normal and abnormal engine operating conditions.
Still a further object of the invention is to provide a fuel shut-off mechanism according to. the immediate preceding object wherein the device is remotely adjustable for controlling the fuel-air ratio delivered to the engine during normal and abnormal engine operating conditions.
These and other'desirable objects inherent in and encompassed by the invention will become more apparent from the ensuing description of a preferred embodiment, the appended claims and the annexed drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view center section taken through the central portion of a carburetor construction showing the arrangement of the fuel shut-off mechanism of the present invention;
FIG. 2 is a center sectional view, partly broken away, illustrating a rotational speed actuated valve which may optionally be included as a component of the fuel shut-off device of FIG. 1;
FIG. 3 is a slightly enlarged sectional view taken on line 3- 3 of FIG. 1 showing a detail of the fuel discharge member component of the present invention; and
FIG. 4 is a slightly enlarged sectional view taken on line 4- 4 of FIG. 1 illustrating a detail of the fluidic device employed in the carburetor construction of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawing the fluidic fuel metering system or carburetor utilized as an environment for the present invention is indicated generally by the numeral 10. The carburetor 10 includes an air-flow conduit 11 having its upper end in communication with the atmosphere, usually through a conventional air filter (not shown), and its lower end in communication with the cylinders through an intake manifold, of an internal combustion engine (not shown). Air flowing through the conduit 1 l is controlled by a conventional throttle valve generally indicated at 12 which is varied by a rotational movement of the throttle valve shaft 13 in a conventionalmanner.
The conduit 11 includes a restriction or venturi portion 14 which reduces the static pressure of air flowing therethrough to create control signal pressures related to the rate of air flow through the conduit 1 l which will be discussed herein more in detail.
The carburetor 10 is provided with a conventional fuel float bowl or float chamber indicated generally at 15. The chamber 15 includes a float 16 connected to an arm 17 pivotally connected at 18 to a side wall 19 of the carburetor 10. The arm 17 is provided with a valve element 20 in cooperative alignment with valve seat 21 in a conventional manner. A source of liquid fuel under pressure above atmospheric is connected to pipe 22 whereby liquid fuel isadmitted into the float chamber .15 via conduit 22 and valve 20,21 until the amount of fuel 23 in the float chamber 15 reaches a predetermined fuel level 24 as indicated in the drawing. The upper portion of the float chamber 15 communicates with the upper portion of the inlet air-flow conduit 1 1 through passage 31 having a port 32 opening into the conduit 11 as shown in FIG. 1'.
The carburetor 10 is provided with a fluidic device generally indicated at 25 which includes an interaction zone 26 having a restriction or inlet nozzle 27, as shown in FIGS. 1 and 4, in communicationwith the float chamber 15 through fuel passage 28. Thus liquid fuel from the float chamber 15 may enter the interaction zone 26 through passage 28 and inlet port or nozzle 27.
The carburetor 10 is provided with a liquid fuel discharge member indicated generally at 29 extending into the air-flow conduit 11 and positioned below the throttle valve 12. The discharge member 29 comprises a tubular element 30 having at least one slit or elongated orifice 33 preferably disposed at right angle with reference to the inlet air-flow conduit 11 as shown in FIGS. 1 and 3, The discharge member 29 communicates with interaction zone 26 of the fluidic device 25 through outlet port 34 and outlet passage 35. Thus liquid fuel from the float chamber 15 is diverted by the nozzle 27 through the interaction zone 26 into port 34 and thereafter conducted to the discharge orifice 33 through outlet passage 35 and discharge member 29.
It will be noted that the float chamber 15 is positioned with respect to the fluidic device 25 whereby the fuel level 24 is maintained at or just slightly below the horizontal plane of the nozzle 27. If the fuel level 24 is above the nozzle 27 liquid fuel from the float chamber 15 will drain into the air-flow conduit 11 during periods when the engine is not operating which would result in loss of fuel and may affect the ability of the engine to start easily. On the other hand, the fuel level 24 should not be substantially below the horizontal plane of nozzle 27 because it would then require an unnecessarily higher pressure difference to cause the liquid fuel to flow through the nozzle 27.
In the drawing it will be observed that the interaction zone 26 of the fluidic device 25 communicates with air-flow conduit 11 through the signal port openings 36 disposed preferably at right angle with respect to the inlet air-flow conduit as indicated in FIGS. 1 and 4. The distance between the nozzle 27 and the signal port opening 36 ideally should be zero. However, practically the distance between the nozzle 27 and pressure signal port opening may be as much as about one-half the total wetted perimeter of the port opening 36. For example a distance of about one-sixteenth inch provides very satisfactory operation. As indicated in FIG. 1, the signal port opening 36 may conveniently be in the form of a slit or elongated aperture which communicates the interaction zone 26 of the fluidic device 25 with the venturi portion 14 of the inlet air-flow conduit 1 1. I
For normal operation of the internal combustion engine served by the carburetor the aggregate cross-sectional area of the orifice 33 in the discharge member 29 is important and should preferably be from one-half to three times the crosssectional area of the nozzle 27. However, as will be apparent later herein, the present invention includes means for adjusting the magnitude of the cross-sectional opening of orifice 33 not only to obtain the optimum size for normal engine operation but also for abnormal engine operating conditions such as, for example, starting a cold engine and subsequent operation thereof until normal engine temperature is reached.
Referring again to the drawing it will be noted that in the inlet air-flow conduit 11 there are three principal signal pressure regions indicated at X, Y, and Z. The rate of metering of fuel 23 from the float chamberlS through the fluidic device 25 is a function directly related to the composite or integrated effect of the three absolute pressure magnitudes existing in regions X, Y, and Z during any predetermined operating condition of the engine. The absolute pressure at region X has been found to be slightly below atmospheric pressure and varies only slightly under all engine operating conditions at any given elevation with reference to sea level. The absolute pressure in region Y at the venturi portion 14 of the air-flow conduit 11 reaches its lowest value when the throttle 12 is at its maximum open position (i.e. maximum throttle engine operation) and rises progressively to a maximum value somewhat below the absolute pressure value in region X when the throttle 12 is nearly closed (i.e. operation of the engine at idling condition). The range of absolute pressure values in region Z has the widest variation. During operation of the engine at idling condition the absolute pressure value in region 2 is very low, that is to say a pressure value of much lower magnitude than that found in regions X or Y under any engine operating condition. On the other hand, when the throttle 12 is at its wide open position (i.e. engine operating at full load) the absolute pressure value in region Z will be slightly greater than the corresponding pressure value in region Y.
In operation, from the above, it will be apparent that under all engine operating conditions the absolute pressure value in region X will always be greater than at either region Y or region 2. Therefore the air pressure in the float chamber 15 will drive the liquid fuel 23 through the nozzle 27. The nozzle 27 is so positioned that the liquid fuel emanating therefrom is directed toward the outlet port 34 and if the fluidic device is properly arranged all fuel delivered into the conduit 11 will preferably be through the orifice 33 of the discharge member 29 during any engine operating condition. Otherwise at wide open throttle or near wide open throttle engine operating condition some fuel may enter the air-flow conduit 11 through the port opening 36. From this it will be apparent that in general operation no fuel is discharged through port openings 36 but,
to the contrary some air may enter these ports 36 and mix with the fuel directed through the outlet passage 35 The foregoing describes a carburetor construction providing a suitable environment for the invention, now to be explained in detail wherein means are provided for remotely controlling the air-fuel ratio including a rapidly operative mechanism for shutting off the fuel source during periods when the engine speed is decelerating under reduced throttle toward a predetermined speed value. The invention may therefore be considered to be an air-fuel ratio control mechanism capable of regulating the cross-sectional area of the fuel discharge orifice 33 from maximum open position to closed position, as may be desired, with means for automatically closing the fuel discharge orifice 33 when the engine or vehicle is decelerating toward a predetermined minimum speed value or, alternatively, during periods when the engine is being driven by the momentum of its load at a speed above its predetermined minimum speed value such as that which occurs when a vehicle is moving downhill.
Referring to FIG. 1 it will be seen that the spray bar 30 of the fuel discharge member 29 is a tubular structure having one end in communication with the outlet passage 35. Disposed in slidable relation within the spray bar 30 is a movable plunger 37 which is capable of being moved rightwardly in FIG. 1 to an extreme position, indicated by the dotted line 38, which closes communication of the outlet passage 35 with the discharge orifice 33 and leftwardly to an extreme position where the entire discharge orifice 33 is in opencommunication with outlet passage 35. Thus, it will be apparent that movement of the plunger 37 correspondingly regulates the flow of fuel from the outlet passage 35 into the inlet air-flow conduit 11 through the variable size opening of the discharge orifice 33 thereby correspondingly regulating the air-fuel ratio delivered to the engine. Means for controlling the position of the plunger 37 in respect of the discharge orifice 33 will now be described.
The air-fuel ratio control mechanism of this invention includes an actuator device generally indicated at 40, which may be integral with the carburetor 10 as shown in FIG. 1 or constructed as a separate component suitably secured, as by screws, to the casing 41. The plunger 37 includes a stem 42 which passes through a hole 43 in the casing 41 and projects into a room 44 of the actuator device 40. The room 44 is divided into a chamber 45 and a compartment 46 hermetically sealed from each other by a flexible diaphragm 47. The stem 42 extends through the diaphragm 47, by conventional clamping seal indicated at 48, and abuts a bushing assembly indicated at 49. The bushing assembly 49 comprises a bushing 50 joumaled for slidable movement through bore 51 in the wall 52 of the actuator device 40 as may be evident from FIG. 1. The bushing 50 is provided with a cylindrical recess 53 having internal threads therein. Threadedly fit within the recess 53 is a pin 54 having a head 55 forming a cam follower. The leftward end of the bushing 50 may be formed into a hexagonal head 50a suitable for wrench-engaging means. Likewise the head 55 of the pin 54 may be provided with a hexagonal-shaped portion 55a also suitable for wrench-engaging means. Thus it will be apparent that by relative rotational movement between the pin 54 and bushing 50 the distance between the abutment 56 of the bushing 50 relative to the cam follower 55 is adjustable. Suitable locknuts or other conventional means (not shown) may be employed to lock the pin 54 from rotational movement with reference to the bushing 50.
A convenient means for engaging the cam follower 55 for adjustably moving the bushing assembly 49 and its abutment 56 may comprise a cam 57 mounted for rotational movement on a shaft 58. A compression spring 59 anchored on the casing 41 and seated on the clamping seal 48 urges the plunger 37 and bushing assembly 49 leftwardly as viewed in FIG. 1 so that the cam follower 55 is urged against the cam lobe 57a. The cam 57 is moved rotatively about the axis of its shaft 58 either by applying sufficient torque to the shaft 58 or by appropriate movement remotely of lever 60 connected to the cam 57. Thus it will be apparent that by proper selection of the curvature of cam lobe 57a the position of the plunger 37 with reference to the elongated orifice 33 varies correspondingly the size of the opening 33 for discharging fuel into the inlet air-flow conduit. From this it will be apparent that the air-fuel ratio may be selectively altered such as for starting and operating a cold engine or changing the air-fuel ratio corresponding to variations in atmospheric pressure such as that which oc curs by reason of changes in altitude.
From the foregoing it will be seen that the bushing assembly 49 and its associated cam 57 provides an operative adjustable stop means for limiting the leftward movement of the plunger 37 as viewed in FIG. 1 and thereby controlling the size of the discharge orifice. It will be obvious to those skilled in the art that an ordinary bolt threadedly fit into bore 51 could be substituted for the bushing assembly 49 and cam 57 thereby providing a stationary abutment 56 thus fixing the maximum size of the discharge orifice 33.
Means will now be described for energizing the actuator device 40 wherein the plunger 37 is moved rightwardly to its extreme position wherein the discharge orifice 33 is closed and thus no fuel is discharged into the inlet air-flow conduit 1 1 from the outlet passage 35. Broadly speaking, this entails communicating the inlet air-flow conduit 11 at signal pressure re gion Z (downstream of the throttle valve 12) with chamber 45 during periods of engine operation when fuel cut-off is desired. 7
The actuator device 40 may be operated by means such as a pressure sensing valve indicated generally at 61 in FIG. 1. The valve'means 61 may comprise a valve housing 62 having axially aligned bores 63, 64 and 65 as shown in FIG. Disposed in the bore 64 for axial movement therein is a valve spool in dicated' generally at 66. Valve spool 66 is provided with lands 67, 68 forming a circumferential groove 69 therebetween. Extending leftwardly from the land 67 the valve spool 66 is provided with a shoulder 70 which serves to limit the leftward movement of the spool 66. Vent 71 in the valve housing 62 is provided to vent the formed compartment 72.
Disposed in compartment 73 formed in bore 64 rightwardly of land 68 is a compression spring 74 which urges the valve spool 66 leftwardly to abut the'shoulder 70 against the valve housing 62 as is evident from FIG. 1. Vent 75 in the valve housing 62 is provided to vent the compartment 73. Port 76 communicates with chamber 45 of actuator device 40 through pipe 77. Port 78 in the valve housing 62 is positioned for continuous communication with circumferential groove 69 irrespective of the axial position of the valve spool 66 in the bore 64. i i
In order to actuate axial movement of the valve spool 66 against the urging of spring 74, the valve means 61 includes a cylinder indicated at 82. Disposed within the bore 63 of cylinder 82 in slidable relation is a piston 79 having the face 80 thereof exposed to the atmosphere as shown in FIG. 1. Piston 79 includes a piston rod 81 slidably disposed in the bore 65 which rod may be, but not necessarily, integral with shoulder 70 of the valve spool 66. The piston 79 in the bore 63 of the housing 62 forms a cylinder cavity 83 communicatively connected to port 78 through pipes 84 and 85. Pipe 85 communicates with signal pressure region 2 of carburetor through pipe 86, shut-off valve (in open position) 87, pipes 88 and 89 and port 90 positioned in casing 41 downstream of the throttle valve 12.
In the arrangement just described it will be seen that when the throttle valve 12 is open to a degree such as that which occurs when the engine is driving a load, the absolute pressure value (i.e. a vacuum) in the cavity 83 of the pressure sensitive valve means 61 will be substantially equal to the absolute pressure value of the signal pressure region Z but the pressure differential then existing between cavity 83 and the atmosphere will be insufficient to move the piston 79 against the urging of the spring 74.- Thus the valve spool 66 of the valve means 61 will remain in the position shown in FIG. 1 and the chamber 45 of the actuator device 40 is in communication with the atmosphere through pipe 77, port 76, compartment 73 and vent 75. Under such operating condition the position of the plunger 37 with reference to the discharge orifice 33 remains under control through manual (or otherwise) operation of the cam 57.
When the throttle valve 12 is substantially closed, and the engine speed is near that which occurs when the engine is permitted to idle under a no-load idling condition, the absolute pressure in the signal pressure region Z communicated to the cavity 83 of the valve means 61 reaches a relatively low value. However, this value is still such that atmospheric pressure on the face 80 of the piston 79 will be insufficient to move the piston 79 such that the land 68 of the valve spool 66 will move toward port 76. Thus when the engine idles .normally the chamber 45 of the actuator device is not yet in communication with signal pressure region Z and therefore the position of the plunger 37 with reference to the discharge orifice 33 remains under control through operation of the cam 57. From this it will be apparent that the size of the piston 79 and the characteristics of the spring 74 should be chosen such that the absolute pressure value in the signal pressure region Z during normal engine idling is barely high enough so that the valve spool 66 will not move sufficiently to communicate port 76 with circumferential groove 69.
When the speed of the engine is elevated under no-load or low load and the throttle 12 is moved into idling position the absolute pressure in the pressure region Z drops to values below the above described normal values because the engine is being driven principally by its own momentum or kinetic energy until its speed reduces or approaches idling speed. A similar drop in the absolute pressure in the pressure region Z occurs also when the throttle 12 is moved substantially to idle position during periods when the engine is being driven by the kinetic energy of its load such as that which occurs when an engine driven vehicle is moving downhill while in gear. Under either of these conditions the resulting absolute pressure value in the pressure region Z being lower than the value obtained under normal engine idling or power producing conditions creates a differential pressure between cavity 83 and the atmosphere so that. the piston 79 moves the valve spool 66 rightwardly such that port 78 communicates with port 76 through circumferential groove 69 thereby communicating the pressure existing in pressure region 2 with chamber of the actuator device 40. The drop in pressure within the chamber 45 permits atmospheric pressure in compartment 46 through vent 91 to overcome spring 59 and drive rightwardly the flexible diaphragm 47, clamping seal assembly 48, stem 42 and plunger 37 to the dotted line 38 thereby closing the discharge orifice 33. Thus all fuel flow is shut off and therefore fuel delivery to the engine is terminated, i.e. zero fuel-air ratio. Under such conditions at least three distinct advantages occur. First, since no fuel is delivered to the engine there can be no combustion and thus the engine functions entirely as a pump. The engine may thus function much more efficiently as a speed retarder than when combustion is permitted to take place if idling air-fuel ratio mixture is delivered to the engine. Second, there is obviously an improved fuel economy. Third, the shutting off of the fuel flow during such periods of operation serves to minimize unwanted engine emissions into the atmosphere.
During periods when the fuel is shut off as above described any air which may have entered into the outlet passage 35 through the apertures 36 will rise thus leaving a column of liquid fuel in the passage 35 which is immediately available for restarting engine combustion. Engine restart commences automatically when the engine speed reduces to some preset value above idling speed at which time the absolute pressure in the signal pressure region Z rises to the restart pressure value. When the pressure in the signal pressure region Z rises to the restart pressure value then the spring 74 of the pressure sensitive valve means overcomes the atmospheric pressure acting on the piston .79 permitting the'chamber 45 to re- 77, port 76, compartment 73 and vent 75. Thus the spring 59 moves the plunger 37 with its associated stem 42 and clamping seal assembly 48 back into abutting relation with abutment 56 of the bushing assembly 49 as shown in FIG. 1. When this occurs the column of liquid fuel (free of air bubbles) in the outlet passage 35 is available for immediate discharge into the inlet air-flow conduit 1 1 through the fuel discharge orifice 33. Since the column of liquid fuel in the passage 35 is at that time temporarily free of air bubbles the initial rate of fuel flow through discharge orifice results in a, temporarily enriched airfuel ratio delivered by the carburetor to the engine.
If desired optionally the actuator device 40 may be rendered inoperative to shut off the fuel flow when the vehicle speed is below a predetermined minimum speed by simply interposing a vehicle speed sensitive valve mechanism, indicated generally at 92 in FIGS. 1 and 2, communicatively connected to pipes 85 and 89 and either closing valve 87 or eliminating valve 87 and associated pipes 86 and 88. The speed sensitive valve 92 merely communicates pipe 85 with pipe 89 during periods when the speed of the vehicle exceeds a predetermined value thus rendering the actuator device 40 operative and, to the contrary, renders the actuator device 40 inoperative when the vehicle speed is at or below the aforesaid predetermined value. One form of speed sensitive valve mechanism is illustrated in FIG. 2 which will now be described.
In FIG. 2 the mechanism 92 comprises a stationary hollow housing 93 forming a first compartment 94 communicatively connected to signal pressure region Z of the carburetor 10 through pipe 89. Disposed within the compartment 94 in journaled relation is a hollow rotor 95 forming a second compartment 96 therewithin. The rotor 95 is provided with an externally protruding shaft 97 suitably connected in driven relation with the vehicle such as from the speedometer cable. The housing 93 is provided with an internal circumferential groove 98 communicatively connected to pipe 85 through port 99. Disposed within the shaft 97 is a passage 100 continuously communicating circumferential groove 98 with the second compartment 96. Positioned at the periphery of the rotor 95 is a poppet valve assembly indicated generally at 101. As shown in FIG. 2 the poppet valve 101 is in open position which occurs when the rotor 95 is rotating above a predetermined speed value thereby communicating the first compartment 94 with the second compartment 96 in which case the pipe 85 is in communication with the pipe 89. Thus the condition exists where the valve means 61 and actuator device 40 is rendered operative as previously described. If the rotational speed of the rotor 95 decreases to a predetermined value then the tension spring 102 will overcome the centrifugal force of the valve body 103 and thus the valve assembly 101 will close. When the valve assembly 101 closes communication between pipe 89 and pipe 85 is terminated. In this condition the valve means 61 is rendered inoperative and the actuator device 40 cannot function to close the discharge orifice 33 in response to the absolute pressure existing in the signal pressure region Z. In order to prevent the possibility of having the chamber 45 under sub-atmospheric pressure when the poppet valve assembly 101 closes a means for automatically venting the chamber 45 to the atmosphere under such condition will now be described.
Disposed within the shaft 97 is a second passage 104 which is in continuous communication with a circumferential groove 105 positioned in the stationary housing 93 as shown in FIG. 2. The circumferential groove 105 is in communication with the atmosphere through the port 106. The second passage 104 also communicates with the second compartment 96 through port 107. The valve body 103 is provided with a valve element 108 positioned such that when the poppet valve assembly 101 is in open position the valve element 108 closes the port 107 thereby precluding communication between the second compartment 96 and the atmosphere when the rotational speed of the valve mechanism 92 is above a predetermined minimum rotational speed value. Under such condition the actuator device 40 is operatively connected to function as hereinbefore described. However, when the speed of the vehicle is below a predetermined value, the poppet valve assembly 101 closes thus terminating communication between pipes and 89 and at the same time opens the valve element 108 thereby venting the second compartment 96 with the atmosphere through port 107, second passage 104 and port 106. In the latter condition the chamber 45 is also vented to the atmosphere because the cylinder cavity 83 is thereby vented to the atmosphere and the pressure sensitive valve means 61 will move to the position shown in FIG. 1 which communicates the pipe 77 with the atmosphere through vent 75. Thus when the speed of the vehicle is below a predetermined value set by the speed sensitive valve mechanism 92 the actuator device 40 is deactivated in which condition fuel is supplied to the engine in an air-fuel ratio consistent with the position of the cam 57.
Although the invention has been described in considerable detail with particular reference to certain proposed embodiments thereof, variations and modifications may be efiected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.
What is claimed is:
1. For a spark-ignition internal combustion engine carburetor having an air-fuel conduit and a throttle valve positioned therein, a fuel-to-air ratio regulating means, comprising,
a. a fuel discharge member including an elongated, generally tubular bar extending normally with respect to the longitudinal axis of said air-fuel conduit and having fuel discharge orifice means formed therethrough disposed downstream of said throttle valve providing communication between the interior of said tubular bar and said conduit downstream of said throttle valve, substantially all of the liquid fuel required by the engine to said conduit being introduced through said discharge orifice means;
b. a movable element associated with said tubular bar and cooperable with said fuel discharge orifice means, the effective cross sectional area of said orifice means being directly dependent upon the position of said movable element with respect to said tubular bar and continually varying in accordance with movement of the movable element with respect to said tubular bar, said movable element being movable between a closed position wherein communication between the interior of said tubular bar and said conduit is precluded and fully open position wherein a pre-established effective cross sectional area of said discharge orifice means affords maximum communication for the flow of liquid fuel between the interior of said tubular bar and said conduit;
0. biasing means yieldably urging said movable element in one direction toward its fully open position;
d. stop means operatively engageable with said movable element to limit movement of said movable element in said one direction and thereby establish the fully open position of said movable element; and
e. actuating means for moving said movable element toward its fully closed position against the resilient action of said biasing means, said actuating means being responsive to the absolute pressure value in said conduit downstream of said throttle valve and being effective to rapidly move said movable element to its closed position and to maintain such closed position when said absolute pressure value in said conduit downstream of said throttle valve is below a predetermined value, said biasing means being effective to rapidly move said movable element in said one direction and into operative engagement with said stop means when the absolute pressure value in said conduit downstream of said throttle valve rises to a value at least equal to said predetermined value.
2. A fuel-to-air ratio regulating means as set forth in claim 1, wherein said discharge orifice means is partially defined by an elongated slit formed through the wall of said tubular bar, the longitudinal axis of said slit being substantially parallel to the longitudinal axis of said tubular bar, and said movable element includes a plunger mounted within said tubular bar for sliding movement along the longitudinal axis of said tubular bar.
3. A fuel-to-air. regulating'means as set forth in claim 2, wherein said actuating means includes an actuating device operatively connected to said plunger, and passageway means extending and providing communication between said conduit downstream of said throttle valve and said actuating device, and a speed responsive valve mechanism interposed in said passageway means, said valve mechanism being responsive to the rotational speed of the engine and being effective to disrupt communication between said conduit downstream of said throttle valve and said actuating device only when the rotational speed of the engine is at and below a predetermined rotational speed to thereby renderthe actuating means ineffective to move said movable element toward its fully closed position against the resilient action of said biasing means.
4. A fuel-to-air ratio regulating means'as set forth in claim 3, wherein said movable element includes an elongated stem having one end fixed to one end of said plunger, and said stop means includes an abutment disposed in the path of movement of said stem, the end of said stem opposite the end fixed to said plunger abutting said abutment when said movable element is in its fully open position and therebylimiting movement of said movable element in said one direction.
5. A fuel-to-air ratio regulating means as set forth in claim 1, further including manually operable adjustment means for said stop means, said adjustment means being manually operable to selectively vary the preestablished effective cross sectional area of said discharge orifice means affording maximum communication for the flow of liquid fuel between the interior x movement of said plunger with respect to said slit.
8. A fuel-to-air ratio regulating means as set forth in claim ,7, wherein said manually. operable adjustment means includes a rotatable cam having a cam surface formed thereon, and a cam follower operatively engaging said cam surface and connected to said abutment for cojoint movement along an axis coincident with the movement axis of said plunger, said cam and cam follower being effective upon rotation of said cam to vary the position of said abutment along the path of movement of said plunger with respect to said slit.
9. A fuel-to-air ratio regulating means asset forth in claim 8, further including remote control means for rotating said cam remotely of the carburetor.
10. A fuel-to-air ratio regulating means as set forth in claim 1, further including a liquid fuel reservoir; passageway means extending between" and' providing fluid communication between said fuel reservoir and said tubular bar; and a fluidic device formed within a section of said passageway means between said fuel reservoir andsaid'tubular bar, said fluidic device being responsive to the absolute pressure magnitudes existing in certain regions of said conduit spaced along the longitudinal axis thereof and being effective to control the fuel of said tubular bar and said conduit when said movable element is in its fully open position.
6. A fuel-to-air ratio regulating means as set forth in claim 5, wherein said discharge orifice means is partially defined by an elongated slit formed through the wall of said tubular bar, the
longitudinal axis of said slit being substantially parallel to the longitudinal axis of said tubular bar, said movable element includes a plunger mounted within said tubular bar for sliding movement along the longitudinal axis of said tubular bar.
7. A fuel-to-air ratio regulating means as set forth in claim 4, further including manually operable adjustment means for said stop means, said adjustment means being operable to selectively vary the position of said abutment along the path of flow rate through said passageway means.
11. A fuel-to-air ratio regulating means as set forth in claim 10, wherein said air-fuel conduit is formed with a reduceddiameter venturi portion upstream of said throttle valve and said fluidic device is disposed within said conduit at said venturi portion, said fluidic device including a wall section of said passageway means partially defining an interaction zone, said fluidic device including a restricted fuel inlet nozzle providing fluid communication between said fuel reservoir and said interaction zone, a signal pressure port for subjecting said interaction zone to the absolute pressure magnitude existing in said conduit at said venturi portion, and an outlet port; said fuel reservoir being subjected tothe absolute pressure magnitude existing in said air-fuel conduit upstream of said venturi portion.
12. A fuel-to-air ratio regulating means as set forth in claim 11, wherein said fluidic device is vertically spaced above said tubular bar, and said passageway means extending between said fluidic device and said tubular bar being capable of serving as means for storing fuel trapped when said movable element is moved to its closed position
Claims (12)
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Claims (12)
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1. For a spark-ignition internal combustion engine carburetor having an air-fuel conduit and a throttle valve positioned therein, a fuel-to-air ratio regulating means, comprising, a. a fuel discharge member including an elongated, generally tubular bar extending normally with respect to the longitudinal axis of said air-fuel conduit and having fuel discharge orifice means formed therethrough disposed downstream of said tHrottle valve providing communication between the interior of said tubular bar and said conduit downstream of said throttle valve, substantially all of the liquid fuel required by the engine to said conduit being introduced through said discharge orifice means; b. a movable element associated with said tubular bar and cooperable with said fuel discharge orifice means, the effective cross sectional area of said orifice means being directly dependent upon the position of said movable element with respect to said tubular bar and continually varying in accordance with movement of the movable element with respect to said tubular bar, said movable element being movable between a closed position wherein communication between the interior of said tubular bar and said conduit is precluded and fully open position wherein a pre-established effective cross sectional area of said discharge orifice means affords maximum communication for the flow of liquid fuel between the interior of said tubular bar and said conduit; c. biasing means yieldably urging said movable element in one direction toward its fully open position; d. stop means operatively engageable with said movable element to limit movement of said movable element in said one direction and thereby establish the fully open position of said movable element; and e. actuating means for moving said movable element toward its fully closed position against the resilient action of said biasing means, said actuating means being responsive to the absolute pressure value in said conduit downstream of said throttle valve and being effective to rapidly move said movable element to its closed position and to maintain such closed position when said absolute pressure value in said conduit downstream of said throttle valve is below a predetermined value, said biasing means being effective to rapidly move said movable element in said one direction and into operative engagement with said stop means when the absolute pressure value in said conduit downstream of said throttle valve rises to a value at least equal to said predetermined value.
2. A fuel-to-air ratio regulating means as set forth in claim 1, wherein said discharge orifice means is partially defined by an elongated slit formed through the wall of said tubular bar, the longitudinal axis of said slit being substantially parallel to the longitudinal axis of said tubular bar, and said movable element includes a plunger mounted within said tubular bar for sliding movement along the longitudinal axis of said tubular bar.
3. A fuel-to-air regulating means as set forth in claim 2, wherein said actuating means includes an actuating device operatively connected to said plunger, and passageway means extending and providing communication between said conduit downstream of said throttle valve and said actuating device, and a speed responsive valve mechanism interposed in said passageway means, said valve mechanism being responsive to the rotational speed of the engine and being effective to disrupt communication between said conduit downstream of said throttle valve and said actuating device only when the rotational speed of the engine is at and below a predetermined rotational speed to thereby render the actuating means ineffective to move said movable element toward its fully closed position against the resilient action of said biasing means.
4. A fuel-to-air ratio regulating means as set forth in claim 3, wherein said movable element includes an elongated stem having one end fixed to one end of said plunger, and said stop means includes an abutment disposed in the path of movement of said stem, the end of said stem opposite the end fixed to said plunger abutting said abutment when said movable element is in its fully open position and thereby limiting movement of said movable element in said one direction.
5. A fuel-to-air ratio regulating means as set forth in claim 1, further including manually operable adjustment means for said stop means, said adjustment means Being manually operable to selectively vary the preestablished effective cross sectional area of said discharge orifice means affording maximum communication for the flow of liquid fuel between the interior of said tubular bar and said conduit when said movable element is in its fully open position.
6. A fuel-to-air ratio regulating means as set forth in claim 5, wherein said discharge orifice means is partially defined by an elongated slit formed through the wall of said tubular bar, the longitudinal axis of said slit being substantially parallel to the longitudinal axis of said tubular bar, said movable element includes a plunger mounted within said tubular bar for sliding movement along the longitudinal axis of said tubular bar.
7. A fuel-to-air ratio regulating means as set forth in claim 4, further including manually operable adjustment means for said stop means, said adjustment means being operable to selectively vary the position of said abutment along the path of movement of said plunger with respect to said slit.
8. A fuel-to-air ratio regulating means as set forth in claim 7, wherein said manually operable adjustment means includes a rotatable cam having a cam surface formed thereon, and a cam follower operatively engaging said cam surface and connected to said abutment for cojoint movement along an axis coincident with the movement axis of said plunger, said cam and cam follower being effective upon rotation of said cam to vary the position of said abutment along the path of movement of said plunger with respect to said slit.
9. A fuel-to-air ratio regulating means as set forth in claim 8, further including remote control means for rotating said cam remotely of the carburetor.
10. A fuel-to-air ratio regulating means as set forth in claim 1, further including a liquid fuel reservoir; passageway means extending between and providing fluid communication between said fuel reservoir and said tubular bar; and a fluidic device formed within a section of said passageway means between said fuel reservoir and said tubular bar, said fluidic device being responsive to the absolute pressure magnitudes existing in certain regions of said conduit spaced along the longitudinal axis thereof and being effective to control the fuel flow rate through said passageway means.
11. A fuel-to-air ratio regulating means as set forth in claim 10, wherein said air-fuel conduit is formed with a reduced-diameter venturi portion upstream of said throttle valve and said fluidic device is disposed within said conduit at said venturi portion, said fluidic device including a wall section of said passageway means partially defining an interaction zone, said fluidic device including a restricted fuel inlet nozzle providing fluid communication between said fuel reservoir and said interaction zone, a signal pressure port for subjecting said interaction zone to the absolute pressure magnitude existing in said conduit at said venturi portion, and an outlet port; said fuel reservoir being subjected to the absolute pressure magnitude existing in said air-fuel conduit upstream of said venturi portion.
12. A fuel-to-air ratio regulating means as set forth in claim 11, wherein said fluidic device is vertically spaced above said tubular bar, and said passageway means extending between said fluidic device and said tubular bar being capable of serving as means for storing fuel trapped when said movable element is moved to its closed position