Internal-combustion engines – Charge forming device – Charge-mixing device in intake
Reexamination Certificate
1999-03-01
2001-05-08
Solis, Erick (Department: 3747)
Internal-combustion engines
Charge forming device
Charge-mixing device in intake
C123S592000, C261S079100
Reexamination Certificate
active
06227185
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to atomization and mixture of liquid fuels with air and more particularly to an improved intake for a venturi and method for combining liquid fuels with air.
2. Background
A variety of devices are employed as fuel metering devices for internal combustion engines. Most often, fuel metering devices include an air intake, a fuel supply and a means for effecting the proper fuel to air mixture for combustion.
A carburetor supplies a liquid fuel, commonly gasoline, and an air mixture to an internal combustion engine in a manner which is most often variable and metered. The process of carburetion employs a negative pressure which is provided by the pistons which draws air through the intake valves and the attached carburetor. A carburetor typically includes a venturi which is employed in the liquid fuel and air mixture process. Air is drawn through an intake of the carburetor past a venturi section, through a throttle valve to the engine for combustion. As air is drawn past the venturi, the velocity of the air increases and the pressure decreases. Fuel is introduced into the carburetor, typically just above the venturi, for atomization in a generally laminar and accelerating flow of air through the intake and venturi. The venturi creates a region of lower pressure providing an advantageous site for atomization of liquid fuel into the passing air. The liquid fuel to be atomized is to drawn to the tip of a tube or other means for dispensing the liquid fuel, which feeds fuel above the venturi. The air stream which flows across the tip of the tube or other dispensing means draws the liquid from the dispensing means spreading it as a film along the walls of the venturi, the air flow eventually lifting away the liquid fuel in the form of atomized droplets.
An air intake may be configured including a primary duct having a secondary duct including a venturi positioned within the passage of the primary duct. The secondary duct including a venturi may be supported and positioned relative to the primary duct by support members.
In U.S. Pat. No. 2,746,802 to Feis, entitled Atomizer for Liquids, a secondary duct including a venturi is shown disposed and supported within a primary duct or venturi. In this case, a secondary duct including a venturi is supported by a fuel line or fuel lines which extend into the interior of the primary duct attaching to and passing through the side wall of the secondary duct. The patent to Feis also teaches the use of aerodynamically shaped structural components placed within an air intake passage for limiting turbulence and increasing laminar flow. In particular, Feis teaches the use of a symmetrically shaped airfoil section or duct through which a fuel supply line passes. Configuring structural components which are placed within an air intake passage to include streamlined or airfoil cross sectional configurations, has been employed to reduce the tendency for s disturbed air flow and a turbulent wake at the downstream edge of structural components that extend within an air flow. In such applications it is generally recognized that paralleling the flow of air and atomized fuel mixture is considered advantageous to the consistency of the results obtained in combustion.
It is also generally recognized that air flow beyond the venturi becomes increasingly turbulent, particularly as the air flow encounters the throttle valve. Depending upon engine load, the throttle valve may be positioned at any angle between zero degrees, (0°), (closed), and ninety degrees, (90°), (open). It is generally recognized that air flowing through an inlet upstream from the throttle valve must divide in order to flow past a partially open throttle valve. This phenomenon results in lateral air movement within the air inlet to provide for a division of the air stream upstream from the throttle valve. It is also recognized that liquid fuel that has not fully atomized has a tendency to localize towards a center portion of the intake flow ultimately being affected by the throttle valve. It is also generally recognized that the reaction of the air flow relative to the throttle valve results in less than optimal fuel distribution downstream from the throttle valve.
What is needed is a device that provides a controlled and even flow of air through the air intake of a fuel metering device such as a carburetor.
What is also needed is a device that provides for a controlled, even and substantially inclined circular or cyclonic flow of air through the air intake of a fuel metering device such as a carburetor. Such a device should provide a more consistent and even mixture of air to atomized fuel and should, in addition, diminish the tendency for increased turbulence, particularly as the air flow encounters the throttle valve.
Additionally, what is needed is a device that provides for a controlled and even flow of air through the air intake of a fuel metering device such as a carburetor thereby optimizing atomization and diminishing the presence of liquid fuel at or near the center portion of the intake flow.
It would similarly be of advantage to provide an air intake conduit that permits an engine to run cooler with increased power output and with the fuel to air mixture ratio leaner than that which is typically required. In addition, it would similarly be of advantage to provide an air intake conduit that permits an engine to operate at increased r.p.m. with more consistent exhaust gas temperatures across the various cylinders of the engine than is currently achievable.
SUMMARY OF THE INVENTION
Accordingly, these and other objectives are achieved by an air intake conduit for a fuel metering device, for instance a carburetor, the air intake conduit including an air inlet passage. In one embodiment of the invention, the air intake conduit includes a primary duct including a passage which permits the flow of air through the primary duct. The primary duct is configured so as to be attachable to the fuel metering device permitting fluid communication of air through the primary duct to the fuel metering device. In one embodiment of the invention, the primary duct includes a venturi section.
An air flow directing vane extends across the passage of the primary duct typically at the upstream end of the primary duct and is configured having a relatively narrow cross section which is oriented in relation to the air flow in such a manner that the air flow directing vane presents a leading edge and a trailing edge to the air flow. The air flow directing vane is also configured and oriented to impart a controlled and substantially inclined circular air flow within the air inlet passage.
The preferred embodiment of the invention includes a plurality of air flow directing vanes attached near the upper or upstream end of the primary duct, extending axially from the sides of the primary duct towards the center region of the air inlet passage. A secondary duct, including a venturi, is attached at the second end of each of the plurality of air flow directing vanes, the secondary duct being positioned for fluid communication of air through the secondary duct into the air inlet passage. Means for dispensing liquid fuel in the region of the venturi for atomization in the air flow is provided.
In one embodiment of the invention, the air flow directing vane is configured as an asymmetrical airfoil including a leading edge and trailing edge. The asymmetrical airfoil is configured such that a first side includes both a leading angle and a trailing angle and a surface having a width greater than the width of the second side of the asymmetrical airfoil. In addition, the second side of the asymmetrical airfoil may be configured having a relatively flat surf ace.
This configuration creates an air flow over the first side of the asymmetrical airfoil that has a velocity which is greater than the flow of air across the second side of the asymmetrical airfoil. As the air passing over the first side of the asymmetrical airfoil converges with the flow
Holland Joseph W.
Solis Erick
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