Patent Application
20080264387
1. Field of the Invention
The present invention relates to systems for the controlled combusting of fuels, and, more particularly, to internal combustion engine system fuel injector systems configured to operate on multiple types of fuel.
In an internal combustion engine fuel is ignited and burned in a combustion chamber, wherein an exothermic reaction of the fuel with an oxidizer creates gases of high temperature and pressure. The pressure of the expanding gases directly act upon and cause a corresponding movement of pistons, rotors, or other elements, which are operationally engaged by a one or transmission systems to translate the element movement into working or motive forces.
The most common and important application of the internal combustion engine is the automobile, and due to its high energy density, relative availability and fully developed supply infrastructure, the most common fuels used in automobile engines in the United States of America and throughout the world are petroleum-based fuels, namely, gasoline and diesel fuel blends; however, a reliance upon petroleum-based fuels generates carbon dioxide, and the operation of millions of automobiles world-wide results in the release of a significant total amount of carbon dioxide into the atmosphere, wherein the scale of the amount generated is believed to contribute to global warning.
The petroleum acquisition and transportation operations associated with producing automotive fuels for the world also result in significant social and environmental impacts. For example, petroleum drilling and transportation discharges and by-products frequently cause significant harm to natural resources. The limited and unequal geographic distribution of significant sources of petroleum within a relatively small number of nations renders large consuming nations (such as the United States) net-importers dependent upon nations and sources outside of domestic political control, which has exasperated or directly resulted in international conflicts, social unrest and even warfare in many regions of the world.
One solution is to reduce the conventional automobile's reliance on petroleum-based fuel by substituting one or more economically and socially feasible alternative fuels, energy sources or motive energy systems. Many types of alternative fuels are available or have been proposed for use with internal combustion engines, including gasoline-type biofuels such as E85 (a blend of 15% gasoline and 85% ethanol) and P-series fuels, and diesel-type biofuels such as hempseed oil fuel or other vegetable oils. Alternative power systems (illustrative but not exhaustive examples include hydrogen combustion or fuel-cell systems, compressed or liquefied natural gas or propane gas systems, and electric motor systems) may also replace an internal combustion engine or be used in combination therewith in a “hybrid” system.
However, conventional internal combustion gasoline or diesel engines are designed to operate on fuel specifications that severely limit the possibilities of using alternative fuels. Since alternative fuel blends diverge greatly from conventional petroleum-based fuel specifications, merely substituting an alternative fuel typically results in poor performance of even in violations of governmental emissions requirements.
A long need is thus felt for a method or a system that addresses the problems discussed above. A need is felt for a system that enables a conventional automobile to efficiently use both conventional petroleum fuel blends and alternative fuels.
The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
wherein the drawings are not necessarily to scale. The drawings are merely schematic representations not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore they should not be considered as limiting the scope.
Referring now to
The pulse width signals and fuel pump 102 fuel pressure determines the amount and rate of fuel injected into each engine combustion chamber, to thereby control the combustion chamber air-fuel ratio (AFR). The AFR is the mass ratio of air to fuel present during combustion. When all the fuel is combined with all the free oxygen within the combustion chamber, the mixture is chemically balanced and this AFR is called the stoichiometric mixture, which is ignited by the automobile ignition system in a timing coordination with cylinder head positioning and anticipated time of ignition and combustion. Each fuel has a preferred AFR or range of AFRs which will achieve optimal fuel combustion when ignited, and which is dependent in part on the amount of hydrogen and carbon found in a given amount of fuel. AFRs below preferred value(s) result in a rich mixture, wherein unburned fuel is left over after combustion and exhausted, wasting fuel and creating pollution. Alternatively, AFRs above preferred value(s) result in a lean mixture having excess oxygen, which tends to produce more nitrogen-oxide pollutants and can cause poor performance and even engine damage.
An engine control unit (ECU) (not shown) typically determines and provides pulse width signals to the fuel injection element 104 appropriate for engine operating conditions and dependent upon expected fuel pump 102 pressures and fuel characteristics. The ECU commonly receives AFR signals from an oxygen sensor located in a vehicle exhaust pipe to monitor the amount of oxygen in the exhaust and uses one or more formula(s) and a large number of lookup tables to determine an appropriate pulse width for a given operating condition, thereby avoiding too-rich and too-lean AFRs by increasing or decreasing fuel injector 104 pulse widths in real-time in a closed-loop control system. The ECU generally computes more than 100 parameters, each having its own lookup table. Some of the parameters even change over time in order to compensate for changes in the performance of engine components, s.a., e.g., a catalytic converter. Depending on the engine speed, the ECU performs these calculations over one hundred times per second.
Problems arise if these same pulse widths and fuel pump 102 pressures are used with alternative fuels. For example, E85 combustion generates lower energy as measured in British Thermal Units (BTUs) than gasoline fuel blends. More E85 fuel must be combusted to provide comparable petroleum fuel blend engine performances under similar operating parameters. One solution is to expand pulse widths, to thereby increase the amount of fuel provided to the fuel injection element 104; however, the computational demands on the ECU to provide multiple pulse width determinations for multiple fuels may exceed its computational capacity. A throttle body injection element 104 at full throttle is commonly open for 100% of a fuel supply period. It is therefore not possible to widen a pulse width or otherwise add more time to the period that the throttle body injector 104 is held open in order to allow more fuel to flow into the engine.
The secondary fuel pump 206 may be programmed or otherwise configured by a manufacturer, an after-market retailer or installer, or by some other service provider. It may be subsequently reprogrammed, as required, to provide optimal fuel injector settings for one or more specified alternative fuels.
The secondary fuel pump 206 and/or also covariable power element 360 are each further in communication with a switch 212 and/or 312, respectively, that toggle each of the secondary fuel pump 206 and/or variable power element 360 into active or inactive states. The switches 212, 312 thus enable use of a conventional fuel by placing the pump/element 206/360 into inactive states, as well as the use of at least one alternative fuel by switching each into an active state. The switch 214 may be manually operated by a user, or ti may be configured to detect a fuel type being used and automatically select between active and inactive states accordingly.
The foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive nor to limit the invention to the precise forms disclosed and, obviously, many modifications and variations are possible in light of the above teaching. For example, alternative fuels practiced by the present invention are not limited to E85 fuels, and other alternative fuels may be practiced. Illustrative examples include P-series fuels, diesel-type biofuels such as hempseed oil fuel or other vegetable oils, liquified natural gas, hydrogen fuels, though others may be appropriate as understood by those in the art. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims.
The present application is a Continuation-in-Part of U.S. Ser. No. 60/914,454 and it claims a priority to the provisional's Apr. 27, 2007 filing date. The present application incorporates the subject matter disclosed in ('454) as if it is fully rewritten herein.
| Number | Date | Country | |
|---|---|---|---|
| 60914454 | Apr 2007 | US |
