Alcohol Fuel Conversion Apparatus for Internal Combustion Engines

1. Field of the Invention

This invention relates, in general, to apparatus for converting engines utilizing petroleum products as fuel to engines utilizing alcohol, and methanol and ethanol, in particular, as a fuel.

2. Description of the Prior Art

The great useage of the traveling public of motorized vehicles equipped with internal combustion engines is well known. Equally well known and long recognized is the pollutant problem of the internal combustion engine when operated with conventional petroleum fuels. Pollution of the atmosphere, because of the exhaust discharge of carbon monoxide and nitrogren oxides, has been a cause of alarm in many of the world's larger cities. Many devices have been created and many techniques employed in attemping to reduce the pollutants of the petroleum fed internal combustion engines. Conversion units utilizing liquid petroleum gas, propane, have been somewhat successful in lowering pollution but have by no means eliminated the toxic substances produced by burning the petroleum fuels. Furthermore, many of the pollution reducing devices result in a decrease of the thermal efficiency of the engine.

Alcohols, and particularly methanol and ethanol, have received much attention as potential non-polluting fuels. Use of these fuels, have not been satisfactory largely because of low efficiency and poor starting characteristics when used with a cold engine. Several devices, such as those disclosed by Noguchi et al, U.S. Pat.No. 4,230,072 and Alm et al, U.S. Pat. No. 3,749,376 have attempted to utilize methanol as a secondary fuel to supplement the primary petroleum fuels to obtain greater efficiency. The petroleum pollution problem still remains, as does the dependence on oil. Oswald et al, U.S. Pat. No. 4,123,997 has sought to increase efficiency of the alcohols by a device which adjusts the advance of the fuel injection in cooperation with a controlled ignition device. Oswald, as do conventional non-vapor type carburetors, injects atomized droplets of the fuel in an air mixture to the intake ports of the engine.

The present invention comprises, generally, conversion apparatus for the operation of internal combustion engines on lower aliphatic alcohol such as methanol and ethanol. The conversion apparatus includes means for heating liquid alcohol, under pressure, to a temperature in excess of the vaporization temperature at ambient pressure; a converter for vaporizing the alcohol at reduced pressure; and a vapor-type carburetor for mixing the alcohol vapor with a selected proportion of air for proper combustion. A more definite description may be found in the appended claims.

The present invention proposes and has for objects, generally, the nearly complete combustion of alcohol as a fuel for a significant increase in efficiency; the concomitant reduction to near zero of exhaust pollutants; and the use of a readily produceable non-petroleum fuel. More specifically, the present invention proposes and has for objects the complete elimination of toxic hydrocarbons; the utilization of methanol and ethanol in conventional internal combustion engines; the use of high compression engines for high efficiency; and a conversion unit which provides rapid and dependable starting of a cold engine.

Additional objects and advantages will become apparent and a more thorough and comprehensive understanding may be had from the following description taken in conjunction with the accompanying drawings forming a part of this specification.

FIG. 1 is a schematic view of a preferred embodiment of the conversion apparatus of the present invention.

FIG. 2 is a sectional view of the preferred fuel tank of the present invention.

Referring now to FIG. 1, an embodiment to be preferred of alcohol fuel conversion apparatus 10 for internal combustion engines, made according to the present invention, is disclosed. Conversion unit 10 includes, generally, fuel storage tank 20, fuel pump 30, preheater assembly 40, primary heat exchanger 50, converter 60, and carburetor 70.

Fuel storage tank 20 may be conventional in design, however in climates where excessive evaporation due to heat absorbed by the tank is a problem it is contemplated that the tank, as shown in FIG. 2, include an outer container 23 provided with an insulative cover 24 of polyurethane or the like and fluid-tight liner or insert 25 located inside container 23, collapsible upon emptying, manufactured of a material which is non-reactive to the alcohol fuel, and provided with a fluid-tight closure 26 for filling.

Fuel storage means 20 is connected to and in fluid communication with pump 30 by means of appropriate conduit 32. Fuel pump 30 may be located at any appropriate place in the system, but is preferably located adjacent the outlet of the storage tank. The pump must be operable to maintain alcohol fuel in the liquid phase at a temperature in excess of the vaporization temperature of the alcohol at ambient pressure, prior to its injection into converter 60. A pump capable of maintaining pressures of 40-50 psi operated off the electrical system of a vehicle is suitable.

For increased thermal efficiency and to utilize waste heat from engine 80, a pre-heater assembly, designated generally by the numeral 40, is installed between pump 30 and primary heat exchanger 50. The pre-heater assembly includes a heat conductive conduit 42 in fluid communication with the primary heat exchanger and fuel storage tank through pump 30, and waste-heat delivery means 44 for delivering waste heat from engine 80 to conduit 42 for heat transference thereto. Delivery means 44 in a water cooled engine may be a water hose for circulating water from and back to the cooling system as indicated by the arrowns, or may be a direct heat-transferring metallic contact between conduit 42 and heated portion of the engine, as for example the exhaust manifold. On an air-cooled engine, a direct metallic contact is preferred to the heating effect of air as a coolant.

Pre-heater assembly 40, in the preferred embodiment, also includes a shunt conduit 46 for by-passing heat exchanger, conduit 42, and a control valve 45 for directing fuel flow. Control valve 45 may be either manually or automatically operated and also serves to check backflow of the fuel to pump 30. For automatic operation, the control valve is solenoid operated in its directive capacity and is activated by a temperature sensor 49 which monitors the temperature of the fuel in conduit 42.

The primary heat exchange means, designated by the numeral 50, is in fluid communication with fuel tank 20 through pump 30 and, where pre-heater assembly 40 is made part of the unit, is connected to the fuel outlet of the pre-heater as by conduit 54. It is understood that all conduits in the apparatus on the fuel storage tank side of converter 60 will be of the high pressure type for withstanding pump pressures and the additional pressure which may be caused by the heating of the fuel. The primary heat exchanger is preferably located as close as is physically possible to converter 60 for prevention of heat loss, and may be integral therewith. Primary heat exchanger 50 includes a low capacity conduit 52, made of copper or other highly conductive metal in heat transference contact with a resistive heating element such as heating coil 55 providing the source of the heat. Switch 51 is used to activate the heating coil. It is imperative that the heat source provide and the heat exchanger accept sufficient heat to raise the temperature of fluid delivered by the heat exchanger to a temperature in excess of the vaporization temperature of the alcohol being used as fuel under ambient pressure. As an example, for use on a Volkswagen motor car, a device was constructed in which conduit 52 had a capacity of 25 ml and in which a resistive heating element drawing approximately 23 amperes current off a 12 volt system was employed. Vaporization temperature of ethyl alcohol was reached in less than one minute of time.

To prevent overheating of the alcohol fuel and possible breakdown of the fuel, a temperature sensing device 59 is used to control the temperature of heating element 55 as by an on-off switch 58. The temperature sensing device may be located in or adjacent to the outlet of conduit 52.

Converter 60 receives pressurized and heated fuel from the primary heat exchanger, preferably through a fuel lock valve 65 which permits fuel flow only when the ignition is turned on. The fuel lock valve may also serve as a pressure relief valve. The converter may include two or more stages of regulation to reduce fuel pressure in the vaporization of the alcohol fuel and may be in the nature of propane converters which are conventional in the art. Like propane converters, the converter may be equipped with a heat transfer system utilizing waste heat from the engine. Unlike propane converters, the converter of the present invention may include a heat transfer system providing heat from the electrical system of a motorized vehicle.

From the converter, alcohol vapor is fed directly to a vapor carburetor 70 which may be identical in construction to the propane-type carburetor. In the carburetor, the alcohol vapors are combined with air, which may or may not be pre-heated, to form a gaseous mixture, as opposed to an atomized mixture, proper for combustion purposes. It is contemplated that the gaseous mixture will allow a much leaner mixture of fuel than an atomized mixture resulting in cleaner burning of the fuel, substantially increased efficiency, and substantially decreased pollutants than combustion of an atomized mixture. The gaseous alcohol-air mixture is then delivered directly or by means of an intake manifold to the cylinders of the engine. The intake manifold is preferably well insulated to avoid condensation.

In operation, and assuming sufficient alcohol fuel in the system, switch 51 is flipped to complete the electrical heating circuit between battery 53 and heating element 55. Heat from the element is transferred through conduit 52 to alcohol contained within the conduit raising the temperature of the alcohol in excess of the vaporization temperature of the alcohol at ambient pressure--for ethyl alcohol, somewhat in excess of 180.degree. F. Temperature sensor 59, controlling on-off switch 58 prevents overheating of the alcohol. Sensor 59 may also be used for providing a temperature read-out on a control panel of a motorized vehicle.

Once fuel contained within conduit 52 of heat exchanger 50 has reached proper temperature, the ignition is turned on; fuel lock valve 65 opened; pump 30 activated; and fuel is pumped through conduit 42 of pre-heater 40 forcing the super-heated liquid alcohol from heat exchanger 50 into converter 60 where it is vaporized and into carburetor 70 where a gaseous mixture of alcohol and air is formed for proper combustion. The mixture is then delivered to the cylinders of engine 80, still in gaseous form, where it is ignited to start the engine. Alcohol fuel is either directed through conduit 42 or through shunt conduit 46 of pre-heater assembly 40, depending upon temperatures sensed by sensor 49.

Having thus described in detail a preferred selection of embodiments of the present invention, it is to be appreciated and will be apparent to those skilled in the art that many physical changes could be made in the apparatus without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.