Not Applicable.
The disclosed invention is related to air and fuel supply systems for internal combustion engines and, particularly, to a fuel injector combined with a carburetor that is modified such that the carburetor provides only air to the engine.
The performance of an internal combustion engine is dependent on a number of factors including the operating cycle (e.g., two-stroke having 360 degrees of crankshaft rotation per cycle, four-stroke having 720 degrees of crankshaft rotation per cycle, or Wankel), the fuel type (e.g., gasoline or diesel) the number and design of combustion chambers, the selection and control of ignition and fuel delivery systems, and the ambient conditions in which the engine operates. Examples of design choices for a combustion chamber are believed to include choosing a compression ratio and choosing the numbers of intake and exhaust valves associated with each chamber.
With regard to fuel delivery systems, carburetors and fuel injection systems are known. Those known systems supply a quantity of fuel, (e.g., gasoline and air), in accordance with the position of the throttle as set by the operator. In the case of carburetors, fuel is often delivered by a system of orficies, known as “jets.” As examples of carburetor operation, an idle jet may supply fuel downstream of a throttle valve at engine idling speeds, and that fuel delivery may be boosted by an accelerator pump to facilitate rapid increases in engine load.
Known fuel injection systems, which can be operated electronically, spray a precisely metered amount of fuel into the intake system or directly into the combustion cylinder. The fuel quantity is typically determined by a controller based on the state of the engine and a data table known as a “map” or “look-up table.” The map typically includes a collection of possible values or “setpoints” for each of at least one independent variable (i.e., a characteristic of the state of the engine), which can be measured by a sensor connected to the controller, and a collection of corresponding control values, for a dependent variable control function, e.g., fuel quantity.
Further, engine performance is substantially dependent on how combustion is accomplished in the ambient conditions. The stoichiometric mass fraction ratio of air to gasoline is approximately 14.7:1. However, it is believed that ratios from about 10:1 to about 20:1 will combust, and that it is often desirable to adjust the air-fuel ratio (“AFR”) to achieve specific engine performance (e.g., a certain level of power output, better fuel economy, or reduced emissions). Properly calibrating the fuel delivery system of the engine to deliver the optimum AFR under all operating conditions is important to optimum engine operation.
Vehicles are commonly manufactured having carburetors. Often, those carburetors provide high quality air flow control through, for example, a butterfly or gate type air valve. Those carburetors, however, may not provide high quality fuel delivery through a float bowl and jets. For example, an amount of fuel supplied through a fuel injector may change more rapidly in response to throttle position than the amount of fuel supplied through a float bowl and jets.
Because the quality of fuel delivery provided by a carburetor is often not as great as fuel injectors, vehicle owners desiring high quality fuel delivery often replace vehicle carburetors with throttle body fuel injectors that deliver both fuel and air to the vehicle engine. Such replacement is, however, typically expensive both in the cost of replacement parts and labor to perform the replacement. The air delivery component of the throttle body fuel injector may, furthermore, constitute a large part of the cost of replacement parts. Thus, there is a need for an apparatus and method that provides fuel injection in a carbureted engine system.
In an embodiment of the present invention, a fuel injector adapter is contemplated. The fuel injector adapter includes a coupling having a first end and a second end and forming a combustion air passageway therethrough. The first end is adapted for coupling adjacent a carburetor combustion air passage 101. The fuel injector adapter also includes a fuel injector mount formed on the coupling and forming a fuel injector passageway passing through the fuel injector mount and coupling and into which a fuel injector may be inserted.
A plate fashioned for attachment to a carburetor to prevent flow of air and fuel through a float bowl is also contemplated.
In an embodiment of the present invention, a throttle and fuel injection device is contemplated. That throttle and fuel injection device includes a carburetor and a fuel injector. The carburetor forms a combustion air passage through which combustion air is provided to the engine and through which fuel is not provided to the engine. The fuel injector is disposed in fluid communication with the combustion air passage and fuel is provided to the engine therethrough.
A method of providing combustion air and fuel to an engine is also contemplated. That method includes metering combustion air flow delivered to the engine through a carburetor and metering fuel delivered to the engine through a fuel injector in fluid communication with the carburetor.
In addition, an article of manufacture is contemplated. The article of manufacture includes a computer readable medium having instructions stored thereon. The instructions cause a processor to control combustion air flow through a carburetor and control fuel delivery through a fuel injector in fluid communication with the carburetor when executed.
The accompanying drawings, which are incorporated herein and constitute part of this specification, include one or more embodiments of the invention and, together with the background given above and the detailed description given below, serve to disclose principles of the invention in accordance with a best mode contemplated for carrying out the invention.
Reference will now be made to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. It is to be understood that the figures and descriptions of the present invention included herein illustrate and describe elements that are of particular relevance to the present invention, while eliminating, for purpose of clarity, other elements found in typical engines, carburetors and fuel injectors. It is also to be understood that the preferred embodiments described herein are not exhaustive of embodiments of the invention, but are provided as examples of configurations and uses of the invention.
The throttle and fuel injection devices and techniques described herein provide solutions to the shortcomings of certain fuel delivery systems. Those of ordinary skill in engine control technology will readily appreciate that the devices and techniques, while described in connection with certain engines and fuel delivery systems, are equally applicable to other engine and fuel delivery systems, wherein air and fuel are delivered to the engine. Other details, features, and advantages of the throttle and fuel injection devices and techniques and the user interface will become further apparent in the following detailed description of the embodiments.
Any reference in the specification to “one embodiment,” “a certain embodiment,” or a similar reference to an embodiment is intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such terms in various places in the specification are not necessarily all referring to the same embodiment. References to “or” are furthermore intended as inclusive so “or” may indicate one or the other ored terms or more than one ored term.
An embodiment of the present invention includes a throttle and fuel injection apparatus and method that provides combustion air for an internal combustion engine through a carburetor and for providing fuel to that internal combustion engine through a fuel injector. The method includes blocking all fuel passages leading into the carburetor and adding a fuel injector to the carburetor. Combustion air is thereby directed into the internal combustion engine through the carburetor while fuel is directed into the internal combustion engine through the fuel injector.
A float bowl 108 regulates the amount of fuel flow from a fuel tank (not shown) into the carburetor 100. The float bowl in the depicted embodiment attaches to the carburetor 100 by way of bolts 109 and may be sealed to the carburetor 100 utilizing a gasket 121 compressed between the carburetor 100 and float bowl 108. Fuel flows into the float bowl 108 through a fuel inlet 110. A float 122 is attached to the float bowl 108 by way of a float pin 123, and may be raised and lowered by the level of the fuel in the float bowl 108 to permit or prevent fuel from flowing into the float bowl 108 as desired. From the float bowl 108, a needle valve 124 operates in conjunction with one or more jets, such as an idle jet 125 and a main jet 126 to regulate the flow of fuel into the combustion air stream that flows through the carburetor 100. A spacer 128 may also be utilized. A throttle position sensor (not shown) may be attached to the depicted carburetor 100 and may be used to communicate the desired load that the operator wishes to impose upon the engine to the carburetor 100 such that appropriate fuel and air will be permitted to flow through the carburetor 100 and into the engine. The throttle position sensor may also communicate the desired load to the engine control unit 460 illustrated in FIG. 11.
The carburetor 100 is an analog device used to regulate air and fuel flow into an engine. To regulate the fuel flow accurately, the carburetor 100 may require atmospheric pressure to be present at various locations 117. Tubes 118 may be attached to the carburetor 100 at a throttle connection 132 to assure that atmospheric pressure is present at each of those locations 117. Those tubes 118 may be attached to ports 120 at the desired locations 117 by way of clamps 119.
A choke 112 is also depicted on the carburetor 100. The choke 112 may be manipulated to enrich the fuel to facilitate, for example, cold engine starts. A hot start may also be provided at 114 to regulate fuel or air flow to facilitate engine starts when the engine is hot.
The fuel injector coupling 204 forms an inlet passageway 208. The inlet passageway 208 may be a smooth unobstructed airtight passageway through which air or fuel and air may pass. The inlet passageway 208 may also be of approximately the same cross-sectional area as the combustion air passage 101 to minimize the restriction of airflow through the fuel injector coupling 204. The fuel injector coupling 204 and fuel injector mount 202 may be fabricated from nylon such that they form a rigid airtight connection to the carburetor 100 when coupled to the carburetor 100. Alternately, the fuel injector coupling 204 and fuel injector mount 202 may be fabricated from a metal, plastic, rubber or another rigid or semi-rigid material. Where one end of the fuel injector coupling 204 is attached to the carburetor outlet 106, the opposite end of the fuel injector coupling 204 may be attached to the intake port of the engine. Where one end of the fuel injector coupling 204 is attached to the carburetor inlet 102, the other end of the fuel injector coupling 204 may be attached to an air cleaner or may be exposed directly to the atmosphere. Other configurations including, for example, connection of the inlet connector to tubes leading to an engine inlet or combustion air source are also contemplated.
As may be seen in
The present invention may be utilized with any known carburetor. Where a slide-type carburetor is utilized, the invention retains the beneficial opening characteristics of the slide throttle and the superior wide open flow characteristics of the slide throttle. It has also been found that positioning the fuel injector 216 at the bottom of the fuel injector adapter 200 and thus targeting injected fuel into the bottom of the airstream is beneficial when utilizing the present invention with a slide throttle. That bottom positioning has been found to create less stratification of fuel in the combustion airstream and better distribution of fuel in the airstream. That may be due to the normal operation of a slide throttle, which permits combustion air to flow through the bottom of the combustion air passage 101 as it opens from a closed position, thus creating better mixture of fuel injected at the bottom of the fuel injector adapter 200 with the combustion air entering at the bottom of the combustion air passage 101. Fuel injection timing, which may be controlled by an engine control unit 460 as illustrated in
In
The modified carburetor 401 may include an inlet connector (not shown), that differs in length from a stock inlet connector that may have attached the carburetor 100 in stock form to a combustion air source such as an air cleaner. The fuel injector adapter 200 in the illustrated embodiment has been lengthened from the length of the original outlet connector (not shown) that attached the carburetor 100 to the engine intake port (not shown). Accordingly, the length of the inlet connector may be reduced by an amount equal to the amount by which the fuel injector adapter 200 has been lengthened over the stock outlet connector so that the throttle and fuel injector assembly 400 will fit in the same space that the carburetor 100 and its connectors originally occupied.
The throttle of the modified carburetor 401 may be operated to open and close in the same manner as the throttle of the unmodified carburetor 100. Thus, airflow in the throttle and fuel injector assembly 400 is controlled in a manner like air flow is controlled in the carburetor 100, while fuel in the throttle and fuel injector assembly 400 is provided by the fuel injector 116.
In one embodiment, the engine control unit 460 receives inputs from sensors that indicate engine desired load and engine speed. In the embodiment illustrated in
The engine control unit 460 includes a processor and memory. Program instructions and maps may be stored in the memory. The program instructions may be in the form of software loaded into the engine control unit 460 from, for example, a disk 462. Those instructions may furthermore determine from the sensed desired load and engine speed the amount of fuel and combustion air to be provided to the engine through the throttle and, if desired, the fuel injector assembly 400. The engine control unit 460 may then operate the fuel injector 216 and the modified carburetor 401 to provide the desired quantities of fuel and combustion air.
While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.
This application claims benefit of U.S. Provisional No. 60/357,427 filed Feb. 15, 2002.
Number | Name | Date | Kind |
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4829966 | D'Angelo et al. | May 1989 | A |
5887574 | Smith | Mar 1999 | A |
6250261 | Santarossa | Jun 2001 | B1 |
6467465 | Lorts | Oct 2002 | B1 |
Number | Date | Country |
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3200550 | Jul 1989 | DE |
0723073 | Jul 1996 | EP |
57091372 | Jun 1982 | JP |
57153963 | Sep 1982 | JP |
02055840 | Feb 1990 | JP |
Number | Date | Country | |
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20030154962 A1 | Aug 2003 | US |
Number | Date | Country | |
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60357427 | Feb 2002 | US |