US2234085A - Internal combustion engine - Google Patents

Description

March 4, 1941. RlLEY 2,234,085

INTERNAL COMBUSTION ENGINE Filed March 20, 1959 I 5751717 L. E157 Patented Mar. 4, 1941 UNITED STATES wins FA ENT OFFICE Glenn L. Riley,

Application March 20,

13 Claims.

This invention relates to internal combustion engines, and the present application is a continuation-in-part of my application for patent Ser, No. 140,728, filed May 4, 1937.

The object of the invention is to provide a process and apparatus for the generation of fuel vapor from heavy, that is to say, the less volatile liquid fuels, under optimum conditions of temperature and air exclusion, the mixing of the fuel vapor with air into a correct combustible mixture, and the control of the rate of generation according to the engine demands.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawing the sole figure is a side sectional view showing apparatus embodying the process of the present invention, and through which the process of the invention may be carried out.

Referring now in detail to th drawing, the numeral I represents in general a carburetor which is here shown as being of the down-draft type, having an axially located nozzle 2 and an air inlet 3, the air entering the annular space about the nozzle 2 through spaces between the spider arms 4. The carburetor includes an adjustable metering pin 5 having a tapered end which extends within a tubular extension 6 of the nozzle. The nozzle, together with its tubular extension, is supported by pivoted vanes I, which move responsively to the air draft created by the piston displacement of the engine. When the draft is heavy the vanes draw the tubular 5 extension 5 downwardly with respect to the tapered end of the metering pin, increasing the fuel opening. When the draft is light, the vanes,

together with the tubular extension 6, move upwardly under the urge of the spring 8, closing, more or less, the annular fuel passage between the end of the extension 6 and the tapered end of the metering pin.

The combustible mixture formed in the carburetor passes through "the intake manifold 9 to the engine Ill. The throttle valve II controls the supply of mixture admitted .to the engine. The carburetor is provided with a fuel inlet passage I92 in communication with the tubular extension and nozzle.

All that has above been described is conventional. However, where such carburetors have been used, fuel in liquid form has been admitted through the passage I2 and has been atomized at the nozzle 2. The mixture has consequently beena mixture of air and very finely divided par- New Orleans, La.

1939, Serial No. 263,089

ticles of liquid fuel which are supposed to completely evaporate in the air in the mixing chamber adjacent the end of the nozzle or in the intake manifold on the way to th engine. Such a mode of operation is, of course, quite feasible and well-known where volatile fuel such as gasoline is employed, but it is quite obvious that one could not expect atomized particles of heavier and less volatile liquid fuels to thoroughly evaporate in the air in the manifold.

The present invention sup-plants the liquid fuel supplied to the carburetor by fuel vapor gener ated from the heavier fuels such as kerosene, distillate or even crude oil, through the instrumentality of heat generated preferably by the engine. Heat is supplied by the exhaust from the engine, and the structura1 embodiment by which the invention is herein illustrated provides an exhaust pipe I3 from the engine surrounding that portion of the intake manifold which is adjacent the engine. It is not essential, however, in carrying out the broader aspects of the invention, that the exhaust pipe shall be associated with the intake manifold.

The generating system of the present invention is in the form of a circuit. It consists of a closed receptacle or chamber I4, to which liquid fuel is supplied and preferably maintained at a given level by means such as a float controlled valve 45. From the bottom of th chamber I4 a pipe I6 passes to a heating coil I1. From the heating coil a'pipe I8 communicates with a downpi-pe or Joy-pass It, the lower end of which is open, and dips beneath the level of liquid fuel in the chamber It. coil I I is located within the exhaust pipe I3. For convenience, it is shown wrapped about the intake manifold but it utilizes the intake manifold solely as a means of support.

Liquid fuel from the chamber I4, entering the coil I1 is changed to a vapor, due to the heat of the exhaust, and the vapor passes through the vapor fuel pipe l8 and the down-pipe or Joy-pass I9 back to the bodyof liquid fuel in the chamber I l, where it is both condensed and absorbed. The fuel passage I2 of the carburetor taps into the fuel vapor pipe at its point of juncture with the down-pipe or bypass, and while the engine is running there is a demand for the generated fuel vapor so that only a relatively small portion of the fuel vapor returns by Way of the by-pass to the liquid fuel chamber.

Referring to the drawing, it will be noted that there is a check valve 20 in the liquid fuel pipe vI6 between the fuel chamber I4 and the coil This is the circuit. The

H, which prevents back flow from the coil into the liquid fuel chamber. Said check valve is maintained closed by a spring 2! strong enough to hold the body of liquid fuel in the chamber l4 when the engine is not running, at which time conditions are static in the generating circuit. There is a valve 2i in the liquid fuel pipe between the chamber I4 and thecoil H which is manually adjusted at the time the engine demand is heaviest, to permit enough liquid fuel to be discharged into the coil to provide a rateof vapor generation supply in excess of the demands of the engine at that time. There is another valve 22 in the vapor fuel pipe l8 at an intermediate point in said vapor fuel pipe, which may be manually adjusted in order to provide a slight excess of pressure on the coil side of said valve, above that on the carburetor side. This provides a storage of some excess fuel vapor under pressure in the system, to meet the demands of sudden throttle opening after a period of com parative idling, during which the heat of the exhaust manifold may have been reduced to a point low enough to slow up the rate of vapor generation.

The construction and the arrangement of the parts constituting the generating circuit are such as to determine the generation of fuel vapor at a rate which'follows very closely the demands of the engine, being only slightly in excess of the engine demand. It will be understood that there is at all times, while fuel vapor is beinggenerated, a plus pressure in all parts of the circuit and including the fuel passage It. At the time of greatest engine demand, that is to say when the pistons of the engine are creating little vacuum, the plus pressure in the liquid fuel pipe I 6 above the valve 2| is at its maximum excess over the plus pressure in the fuel by-pass l2, and that part of the circuit which is on the coil side of the valve 21 so that the maximum amount of liquid fuel is drawn past the check valve 20 and the valve 2|. This causes the maximum amount of vapor to be generated in the coil l1. When the engine demand decreases, the plus pressure in the fuel passage l2 and the vapor limb of the circuit builds up so that the pressure differential on opposite sides of' the valve 2| diminishes, and less liquid fuel is drawn into the coil ll; thus, less fuel vapor is generated. In this manner, the generation of vapor follows closely the demands of the engine, it being understood that to assure an adequate supply of fuel vapor at all times, the valve 2| is adjusted to permit slightly more vapor to be generated than is to be utilized. the excess being returned to the chamber l4 through the down-pipe or by-pass l9 where it is condensed or reabsorbed into the body of liquid fuel in said chamber. Further close control of the proportion of fuel vapor admitted to the engine is accomplished through the relationship of the tension of the spring 8 to the weight of the liquid column in the lower end of the bypass l9. The spring tension is slightly greater than the weight of the liquid column, so that at low speeds of the engine, when the vanes 1 are not depressed, the excess vapor pressure in the circuit will force down the column of liquid in the Icy-pass, admitting the excess vapor to the chamber I4, rather than force down the nozzle extension 6 against the tension of the spring 8.

In its practical embodiment, the coil may be termed. a flash-type vaporizer instantaneously converting the liquid fuel into vapor. With this end in view, a venturi 23 is inserted at the anterior end of the coil H to increase the velocity of the incoming jet of liquid fuel to throw it as far forward as possible through the convolutions of the coil. The coil is of such length as to superheat the vapor which preferably has a temperature below the cracking point of the oil vapor, but well above its condensation point. Within this high temperature range the fuel vapor would be subject to spontaneous combustion in the presence of oxygen, consequently, it is an important feature of the invention that the fuel vapor in its passage-through the generating circuit .is altogether excluded from air.

In order to prevent the fuel vapor at this high .temperature from bursting into a sooty smoke upon contact with air at the mouth of the nozzle of the carburetor, it is subjected to atmospheric cooling in the fuel vapor pipe l8, and also in the carburetor fuel passage [2, which is in the path of the incoming air. While this cooling lowers the temperature of the fuel vapor to the point below that of spontaneous combustion, it still remains above the point of condensation.

The mixture of fuel vapor and air in the carburetor is preferably subjected to reheating on its way to the engine, to prevent the possibility of condensation. This reheating is accomplished through the fact that the portion of the intake manifold between the carburetor and engine is jacketed by the exhaust manifold,

When cold, the engine is started with a volatile fuel, such as gasoline, which is supplied to the chamber. l4 through the fitting 24 which leads to a gasoline supply. A valve 25 selectively controls the supply of either gasoline or the heavy fuel. It is contemplated that the driver of an 'auto vehicle in which the present invention is installed, shall, when within a mile or so of the end of his trip, operate the valve 25 to cut oil the heavy fuel and admit the gasoline to the chamber M. By the time he has run to the end of his journey the heavy fuel will all have been depleted from the chamber l4 and been replenished with gasoline. The next morning, for example, the cold engine is started in the customary manner, the carburetor drawing liquid gasoline up the by-pass l9 and through the nozzle 2, the carburetor operating upon an atomized mixture the same as it does in a convention installation. The valve 25 may be immediately shifted to cut off the gasoline and admit the heavy fuel. By the time the gasoline in the float chamber l lhas been depleted, the coil I! will be generating vapor, the pressure of which vapor will have depressed the liquid fuel column in the by-pass l9 so that the carburetor will now be operating upon a mixture of air and fuel vapor.

When starting a cold engine the time required for heating the coil to a vaporization temperature may be shortened by the employment of a wick heater 26, consisting of a gasoline chamber 2! located beneath the coil l1 and provided with a wick which extends part way up on each side of the coil. Gasoline is admitted to said chamber through a tube 28 controlled by a valve 29 which is designed to be closed immediately after enough gasoline has been drawn to supply the wick chamber. A spark plug 30 in the wick chamber connected into the ignition system of the engine ignites the gasoline in the wick chamber.

The portion of the intake manifold directly beneath the nozzle of the carburetor is formed with a well or depression 3|, adapted to catch any drip from the carburetor and to convert it into vapor through heat acquired from the exhaust manifold.

While I have in the above description disclosed what I believe to be a preferred and practical embodiment of my invention, it will be understood to those skilled in the art that the details of construction and the arrangement of parts as shown and described, are merely by way of example and not to be construed as limiting the invention as defined in the appended claims.

What I claim is:

1. In combination an internal combustion engine, a carburetor having an air inlet and a fuel nozzle discharging into a mixing chamber, a heavy fuel vapor generating system comprising a fuel circuit including a liquid fuel chamber, a vaporizer, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said liquid fuel chamber,a pipe connecting said fuel vapor conduit to the nozzle of said carburetor, an adjustable valve in the liquid fuel conduit designed to be set with relation to the variable engine suction, to supply liquid fuel to the vaporizer at a rate to slightly exceed the fuel vapor demand of the engine, and an adjustable valve in said vapor fuel conduit designed to be set to maintain optimum excess vapor pressure in said conduit on the side of said valve toward said Vaporizer.

2. The combination as claimed in claim 1, the elements comprising said fuel circuit being constructed to exclude air from said circuit.

3. The combination as claimed in claim 1, in which the temperature of generation is normally above the point at which the fuel vapor will spontaneously burn, but below the cracking point, the elements comprising said fuel circuit being constructed to exclude air from said circuit to prevent the possibility of spontaneous combustion within said circuit, and means to cool said vapor to a point below that at which it will spontaneously burn, said means being anterior to the point at which the fuel vapor contacts air at the mixing chamber of the carburetor.

4. In combination an internal combustion engine, a carburetor'having an air inlet, said carburetor being of that type having a metering pine and a fuel nozzle tube movable away from said metering pin responsive to engine suction to increase the fuel content of the combustible mixture, in which the opening movement is resisted by the pressure of a spring, a heavy fuel vapor generating system comprising a fuel circuit including a liquid fuel chamber, a vaporizer, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said liquid fuel chamber, apipe connecting said fuel vapor conduit to the nozzle of said carburetor, a valve between said liquid fuel chamber and said vaporizer to determine the supply of liquid fuel to said vaporizer, a valve in the vapor fuel conduit intermediate said vaporizer and carburetor for maintaining a superior fuel vapor pressure in that part of said vapor fuel conduit on the side of said valve toward said vaporizer, the tension of said carburetor spring being slightly greater than the weight of the column of liquid standing above the open end of said vapor fuel conduit within said liquid fuel chamber, whereby under low vacuum conditions the excess fuel vapor will selectively displace the liquid column in said fuel vapor pipe and flow to said liquid fuel chamber, rather than depress the fuel nozzle tube and unduly enrich the mixture in the carburetor,

5. In combination an internal combustion engine including an exhaust pipe, a carburetor having an air inlet and a fuel nozzle discharging into a mixing chamber, a heavy fuel vapor generating system comprising a fuel circuit, including a liquid fuel chamber, a vaporizer, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said fuel chamber, a pipe connecting said-fuel vapor conduit to the nozzle of said carburetor, an adjustable valve in the liquid fuel conduit designed to be set, with relation to the variable engine suction, to supply liquid fuel to the vaporizer at a rate to slightly exceed the fuel vapor demand of the engine, said vaporizer being within said exhaust pipe and heated by the exhaust from the engine.

6. In combination an internal combustion engine, including an exhaust pipe, a carburetor having an air inlet, and a fuel nozzle discharging into a mixing chamber, a heavy fuel vapor generating system comprising a fuel circuit including a liquid fuel chamber, a vaporizer located within said exhaust pipe and heated by the exhaust from the engine, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said fuel chamber, a pipe connecting said fuel vapor conduit to the nozzle of said carburetor, a spring closed check valve in said liquid fuel conduit to prevent back flow of liquid fuel into said liquid fuel chamber and to prevent flow of liquid fuel from said liquid fuel chamber to said vaporizer when there is no pressure differential in said circuit, an adjustable valve in said liquid fuel conduit designed to be set With relation to the variable engine suction, to supply liquid fuel to the vaporizer at a rate to slightly exceed the fuel vapor demand of the engine, the excess fuel vapor passing through the open end of said vapor fuel conduit into said liquid fuel chamber.

7. In combination an internal combustion engine including an exhaust pipe, a carburetor having an air inlet, and a fuel nozzle discharging into a mixing chamber, an intake pipe leading from said mixing chamber to said engine, a heavy fuel vapor generating system comprising a fuel circuit including a liquid fuel chamber, a vaporizer, said exhaust pipe enclosing said vaporizer and jacketing said intake manifold, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said fuel chamber, a pipe connecting said fuel vapor conduit to the nozzle of said carburetor, an adjustable valve in the liquid fuel conduit designed to be set with relation to the variable engine suction, to supply liquid fuel to the vaporizer at a rate to slightly exceed the fuel vapor demand of the engine, said excess fuel vapor being returned to the liquid fuel chamber through the open end of said vapor fuel conduit, the elements compris ing said fuel circuit being constructed to exclude air from said circuit, the portion of said vapor fuel conduit adjacent said carburetor, and including the pipe which connects said fuel vapor conduit to the nozzle of said carburetor being exposed to atmospheric cooling to prevent spontaneous combustion of the fuel vapor at the mixing chamber of the carburetor, the mixture from said carburetor passing through the exhaust pipe jacketed intake pipe on its way to the engine.

8. Process for preparing combustible mixture for an internal combustion engine employing the vapor of heavy hydrocarbon oils as a fuel constituent comprising, conducting the fuel in a circuit in the course of which heavyliquid fuel is vaporized at a rate proportional to engine demands and in slight excess of said demands, and the excess vapor returned to the body of liquid fuel in said circuit, carrying out the vaporization at a temperature sufficiently above the condensation point of the vapor to ensure against condensation of the vapor in said circuit up tothe point at which said excess vapor enters the body of liquid fuel, excluding the fuel throughout said circuit from air, conducting fuel vapor from said circuit to a carburetor, cooling the thus conducted vapor prior to its reaching the mixing chamber of the carburetor sufficiently to prevent spontaneous combustion, but not sufficiently to cause condensation and mixing the thus cooled vapor with air.

9. Process for preparing combustible mixture for an internal combustion engine comprising vaporizing a relatively non-volatile hydrocarbon fuel constituent by application of heat thereto at a range of temperature below the cracking point but above the oxidizing point of the hydrocarbon, with exclusion of air, conducting the vapor toward a mixing point, successively at the temperature range at which it was generated, with exclusion of air, then prior to its reaching the mixing point, cooling it to a temperature above its point of condensation but below its oxidizing temperature, the cooling being done with exclusion of air, mixing the thus cooled vapor with air at the mixing point, and conducting the mixture to an internal combustion engine while maintaining its temperature above the condensation point of the hydrocarbon constituent.

10. In combination, an internal combustion engine, a carburetor having an air inlet, a conduit fuel supply and having a portion thereof formed as a coil around said conduit, and connected at its other end to the air intake of said carburetor, a pipe connected to the exhaust of said engine and enclosing said coil and the part of said conduit encircled thereby, said pipe being provided with a slot directly below said coil, a receptacle closing said slot, a wick in said receptacle, valve controlled means for connecting said receptacle to said source of fuel supply, and means for igniting the fuel saturated wick in said receptacle to apply a priming heat to said coil and that part of the conduit encircled thereby.

11. In combination, an internal combustion engine, a carburetor having an air inlet, a conduit adapted to connect the outlet of said carburetor to the intake of an internal combustion engine, a source of liquid fuel supply, a pipe connected at one end adjacent said outlet to said source of fuel supply and having a portion thereof formed as a coil around said conduit, and connected at its other end to the air intake of said carburetor, a pipe connected to the exhaust of said engine and enclosing said coil and the part of said conduit encircled thereby, said pipe being provided with a slot directly below said coil, and means connected to said source of fuel supply and operable through said slot to apply a priming heat to said coil and that part of the conduit encircled thereby. g

12. In combination with a carburetor having an air inlet and a fuel nozzle discharging into a mixing chamber, a heavy fuel vapor generating system comp-rising a fuel circuit including a liquid fuel chamber, a vaporizer, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said liquid fuel chamber, a. pipe connecting said fuel vapor conduit to the nozzle of said carburetor, an adjustable valve in the liquid fuel conduit designed to be set with relation to variable air flow through said carburetor air inlet to supply liquid fuel to the vaporizer at a rate to slightly exceed the demand of said carburetor and an adjustable valve in said vapor fuel conduit designed to be set to maintain optimum excess vapor pressure in said conduit on the side of said valve toward said vaporizer.

13. In combination with a carburetor having an air inlet, said carburetor being of that type having a metering pin and a fuel nozzle tube movable away from said metering pin responsive to variable air flow through said air inlet to increase the fuel content of the combustible mixture, in which the opening movement is resisted by the pressure of a spring, a heavy fuel vapor generatingsystem comprising a fuel circuit including a liquid fuel chamber, a vaporizer, a liquid fuel conduit connecting the lower part of said liquid fuel chamber with said vaporizer, a vapor fuel conduit connected to said vaporizer and having an open end dipping below the liquid level in said liquid fuel chamber, a pipe connecting said fuel vapor conduit to the nozzle of said carburetor, a valve between said liquid fuel chamber and said vaporizer to determine the supply of liquid fuel to said vaporizer, a valve in the vapor fuel conduit intermediate said vaporizer and carburetor for maintaining a superior fuel vapor pressure in that part of said vapor fuel conduit on the side of said valve toward said vaporizer, the tension of said carburetor spring being slightly greater than the weight of the column of liquid standing above the open end of said vapor fuel conduit within said liquid fuel chamber, whereby under low air flow conditions in the carburetor, the excess fuelvapor will selectively displace the liquid column in said fuel vapor pipe and flow to said liquid fuel chamber, rather than depress the fuel nozzle tube and unduly enrich the mixture in the carburetor.

GLENN L. RILEY.

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