GB2049805A - Separating Fuel from I.C. Engine Intake Mixtures - Google Patents

Abstract

Fuel in a mixture from a carburettor 10 which impinges on a baffle plate 19 in a separator 16 flows to an outlet 23. The remaining mixture flows through an outlet 22 to a chamber 26 in which it is mixed with the separated fuel which has been vaporised and mixed with secondary air in a heat exchanger 30. The exchanger 30 contains a tube (44), Fig. 2 (not shown), containing a plurality of flow tubes (52), extending within a chamber defined in the engine exhaust manifold (48). The vaporised fuel is introduced into the centre of a venturi (67), Fig. 4 (not shown), in the chamber 26. <IMAGE>

Description

SPECIFICATION System for Obtaining Complete Combustion of Fuel in a Gasoline Engine Background of the Prior Art A fuel vaporizing system of the same general type as the present invention is disclosed in U.S.

Patent 3,1 16,988, which issued in the name of Alfred E. Lauder on January 7, 1964, and which is assigned to the present inventor. The system described in the patent is one in which the air and fuel are separated from the mixture obtained from the carburetor, and in which the fuel is preheated and vaporized, and is then inter-mixed with the relatively cool air in a mixer, before being introduced into the intake manifold of the engine.

In the earlier prior art pre-heating systems, the mixture of air and fuel was pre-heated to a high temperature to vaporize the fuel. However, the air in the mixture, upon being heated, was caused to expand so that a lesser amount of air was fed to the engine than was required for complete combustion. Thus, the fuel was not completely burned within the prior art engine, and on the average of 30% of the unburned fuel was lost out of the tailpipe, with a consequence 30% loss in mileage per gallon, and an average of 25% of the weight of the fuel being emitted as carbon monoxide.

In the system of the present invention, in which the major part of the air is separated out from the fuel in the improved mixture of the invention, and in which the relatively cool air from the separator is subsequently re-mixed with the fuel, after the fuel has been pre-heated and vaporized, assures that adequate amounts of air will be fed into the engine so that complete combustion may be realized.

The system of the invention makes it possible to burn diesel fuel completely in a gasoline engine, with resulting increase in safety and decrease in cost.

The fuel vaporizing system of the invention comprises a carburetor for providing a fuel-air mixture of the proper precisely metered proportions for all engine speeds; a separator chamber which includes a baffle plate and which functions to separate the fuel from the fuel-air mixture received from the carburetor; a heat exchanger for receiving the fuel from the separator to convert the fuel into a dry vapor; and a Venturi-type mixer for remixing the relatively cool, unheated air from the separator and the dry vaporized fuel from the heat exchanger prior to their introduction into the intake manifold.

The present invention provides an improved and simplified separator for use in the fuel vaporizing system, which includes an internal baffle plate against which the air-fuel mixture fed into separator is directed at high velocity and impacted, which impact causes the liquid fuel to be separated from the air and to flow down the baffle plate to an outlet in the bottom of the separator adjacent to the lower end of the baffle plate which feeds the liquid fuel through an appropriate pipeline to the heat exchanger.

Brief Description of the Drawings Figure 1 is a schematic representation, partly in section, of a fuel vaporizing system which incorporates the improved separator of the present invention; Figure 2 is a side section of a heat exchanger used in the system of Figure 1; Figure 3 is a cross-section of the heat exchanger taken along the lines 3-3 of Figure 2; and Figure 4 is a view, partly in section, of a mixing chamber included in the system of Figure 1.

Detailed Description of the Invention With reference to Figure 1 of the drawing, a present-day standard carburetor 10, of any good make, may be used in the fuel vaporizing system.

The carburetor is equipped with a usual air strainer through which the inlet air flows.

Preferably the air strainer is suitably shaped so that it can be mounted in front of the radiator to keep the inlet air as cool as possible and in a relatively compressed state. The carburetor 10 is designed to receive fuel and air in the usual manner so as to provide the desired precisely metered fuel-air mixture at the proper fuel-air ratio as required by the engine at the different engine speeds, and to atomize the fuel. A conventional throttle valve (not shown) is positioned at the outlet of the carburetor, and this throttle valve controls the amount of fuel-air mixture fed to the internal combustion engine to control the speed of the engine.

The carburetor 10 is mounted directly over a separator 1 6 which incorporates the concepts of the present invention, and the carburetor is coupled to the separator through a passageway 1 8. The separator 16, as shown, has a flat baffle plate 1 9 mounted in an inclined position in its interior in a position to extend across the entrance from passageway 1 8. The fuel-air mixture from the carburetor enters the separator at high velocity through the entrance.The baffle plate 1 9 is positioned in the separator chamber 16, in the inclined position shown in Figure 1, so that the fuel-air mixture entering the separator chamber strikes the baffle plate, causing the liquid fuel to be separated out from the mixture and to run down the baffle plate and out through a fuel outlet port 23.

The separator 1 6 has an air outlet port adjacent to its top, and a tubular pipeline 24 is coupled to the air outlet port. The pipeline 24 couples the air outlet port to a Venturi mixing chamber 26. The details of mixing chamber 26 are shown in Figure 4. The outlet of the mixing chamber is coupled to the intake manifold 28 of the internal combustion engine.

The fuel outlet port 23 is formed in the bottom of the separator chamber 1 6 at the lower end of baffle plate 19, and this outlet port is coupled through a pipeline 20 to a heat exchanger 30.

Details of the heat exchanger 30 are shown in Figures 2 and 3.

As best shown in Figure 2, an atomizing unit 29 has an L-shaped tubular configuration, and it is threadably attached to the lower end of separator chamber 1 6 by a suitably threaded fluid-tight coupling 34. The atomizing unit 29 has a first internal passage 36 which extends down from the outlet port of the separator chamber 1 6 into the atomizing unit. The atomizing unit also includes a second internal passageway 38 which extends at right angles to the passageway 36 to the outlet end of the atomizing unit. The passageway 38, as shown in Figure 2, intersects the passageway 36.

A nozzle tip 42 is threaded into the passageway 38 at the outlet end of the atomizing unit 29, as shown in Figure 2. A nozzle tube 40 is mounted in the atomizing unit coaxial relationship with the passageway 38, as shown. The righthand end of tube 40 in Figure 2 may be open to the atmosphere. The tubular member 41 is coupled to the right-hand end of the tube 40 by means of an appropriate fitting 43. The left-hand end of the tube 40 and the tip 42 form a nozzle at the outlet end of the atomizing unit 29.

The vacuum pressure in the intake manifold of the internal combustion engine creates a suction pressure at the outlet end of the atomizing unit 29.

When the throttle is closed; and the engine is idling, this suction pressure causes air to flow in through the tube 40 in the atomizing unit.

Therefore, any liquid fuel that may enter the atomizing unit under these conditions is quickly drawn into a spray by the suction pressure and by the action of the air through the tube 40.

As the throttle is opened, more fuel is supplied down into the atomizing unit 29 together with a iimited amount of air. This fuel-air mixture passes through the passageway 38 and is drawn by the vacuum pressure of the intake manifold through the outlet end of the atomizing unit 29. The fuel, therefore, emerges as a spray at the nozzle tip 42.

The air passing in through the tubular member 41, and in through the separator chamber 16, acts in a differential manner, so that there is always sufficient air at the nozzle tip 42 to create a spray of the liquid fuel at that point, regardless of the position of the throttle.

The left-hand end of the atomizing unit 29 in Figure 2 extends into a first end of the heat exchanger 30. The heat exchanger 30 includes an inner tubular member 44, and the outlet end of the atomizing unit 29 is coupled into the end of the tubular member 44. This coupling is achieved by threading the tubular member 44 into the threaded end of the atomizing unit 29. The tubular member 44 is mounted in a semi-circular tubular member 46 in coaxial relationship therewith. The semi-circular tubular member 46 is welded or otherwise mounted on the exhaust manifold 31 of the associated internal combustion engine.

The opening portion of the tubular member 46 faces an elongated opening in the exhaust manifold 31, which opening is enclosed by the tubular member 46, as best shown in Figure 3.

The tubular member 46 is welded to the exhaust manifold, as shown by the weld seam 50. This enables the tubular member 44 supported within the semi-circular tubular member 46 to be disposed in intimate engagement with the hot exhaust gases passing through the manifold. The outer surface of the tubular member 44, and the inner surface of the tubular member 46, are radially spaced from one another to form an annular chamber for receiving the hot exhaust gases.

It will be evident that the resulting configuration of the heat exchanger assembly 30 is extremely compact, and the assembly adds virtually nothing to the overall size of the exhaust manifold of the associated internal combustion engine.

A plurality of smaller tubes 52 are supported adjacent one another within the tubular member 44 by brackets 54 and 56. The right-hand ends of the latter tubes are spaced, for example, a particular distance from the end of the tubular member 44 and, as shown in Figure 2, the smaller tubes 52 are shorter than the tubular member 44.This provides a space in the tubular member 44 between the nozzle formed at the outlet end of the atomizing unit 29 and the right-hand ends of the tubes 52. This permits the sprayed fuel from the atomizer to pass through the tubes 52 in iritimate engagement with the walls of these tubes for complete vaporization of the fuel.

In a constructed embodiment of the invention, the side of the exhaust manifold of a usual internal combustion engine was cut to form a longitudinal slot therein, and a one and onequarter inch pipe was formed into a semi-circular trough to form the tubular member 46. This trough was welded to the exhaust manifold by welds, such as the weld seams 50 in Figure 3.

The tubular member 44 in the constructed embodiment had an outer diameter of one inch.

The tubular member was supported within the trough 46 in a coaxial manner to provide clearance between the two members so as to permit the hot exhaust gases to circulate around the tubular member 44.

The small tubes 52 in the constructed embodiment had an outer diameter of 3/1 6 of an inch, and a plurality of the order of thirteen or fourteen of these tubes were supported in the tubular member 44. The tubes 52 in the constructed embodiment were spaced a distance of two inches from the nozzle at the outlet end of the atomizing unit 29. The above dimensions are set forth, of course, merely by way of an -illustrative example, and they are not intended to limit the invention in any way.

The heat exchanger 30 uses the heat from the exhaust gases to raise the temperature of the atomized fuel passing through it from the atomizer. As mentioned above, when the throttle 1 2 is closed, air for atomizing the fuel is supplied through the tubular member 41 in the atomizing unit. Then, as the throttle is opened, this auxiliary air through the tubular member 41 drops off and air from the separator chamber 1 6 serves to provide the desired spray effect of the fuel at the outlet end of the atomizing unit.

The cooperative differential action of the air through the tubular member 41 and from the separator chamber 16 in conjunction with the suction pressure exerted by the intake manifold of the engine. assures that adequate fuel atomization will occur at the nozzle tip 42 for all engine speeds and at all positions of the throttle 12, so that at all times the fuel enters the heat exchanger 32 in the form of a fine spray.

The outlet of the heat exchanger 32 is coupled by a fitting 58 (Figure 2) to a pipeline 64 which extends to the mixing chamber 26 of Figure 4.

The pipeline 64 terminates in the mixing chamber in a nozzle 65 as shown in Figure 4.

The threaded joint 58 threadably engages the left-hand end of the tubular member 44 in Figure 2, drawing that member into a firm assembled coaxial relationship with the tubular member 46.

Gaskets 60 and 62 may be provided at the ends of the tubular members 44 and 46, as shown, to assure a fluid-tight assembly.

As mentioned above, the pipeline 24 is also coupled to the mixing chamber 26, and this latter pipeline introduces the air from the separator chamber 1 6 into a portion of the mixing chamber 26 surrounding the nozzle 65, as best shown in Figure 4. A Venturi tube 67 is positioned in the mixing chamber 26 in co-axial relationship with the nozzle 65, and this Venturi tube defines an annular passage through the mixing chamber 26 for air from the pipeline 24 and for the gaseous fuel from the nozzle 65. The diameter of the nozzle 65 may, for example, be three-eighths of an inch, and the minimum diameter of the Venturi tube 67 may, for example, be of the order of one inch to one and one-half inches.

It is well known that a fast moving stream of fluid flowing, for example, through a restricted area, such as a Venturi tube, will produce a high vacuum in a nozzle extending into the Venturi tube.

For example, if a nozzle, coupled to a fuel line, is positioned to extend coaxially into a Venturi tube: and if fluid, such as air, is passed through the Venturi tube, the passage of the fluid will, by aspirating effect, create a suction pressure in the nozzle which will serve to draw fuel through the fuel line and into the air stream.

The principle outlined above is, per se, known to the art, and is used as a basis for many types of vacuum pumps.

The purpose of the Venturi tubes 67 in the mixing chamber 26 is to provide an aspirating effect on the gaseous fuel drawn through the line 64. The effect of the Venturi tube 67 in its cooperation with the nozzle 65 is to create a greater suction in the heat exchanger 32 than exists in the separator chamber 16.

That is, the system, due to the aspirator action in the mixing chamber 26. provides for more vacuum in the heat exchanger 32 from the vacuum pressure of the intake manifold of the associated internal combustion engine, than in the separator chamber 18. This creates the desirable condition of no fuel build-up in the separator 1 6 or in the heat exchanger 32. The resulting vacuum pressure differential renders it impossible for any liquid fuel to build up in the separator chamber 16, in the atomizing unit 30, or in the heat exchanger 32.

The dimensions of the Venturi tube 67 in the mixing chamber 26 can be selected for any particular application to be such that the correct vacuum pressure differential relationship is achieved to provide that for no accumulation of fuel in any part of the fuel vaporizing assembly of the invention at any engine speed.

Therefore, under low speed and idling conditions, the above discussed vacuum pressure differential, in conjunction with the auxiliary air drawn in through the tube 41 in the atomizing unit 30, assures that all liquid fuel in the separator chamber 16 will be drawn into the heat exchanger 32 and passed through the mixing chamber 26 to the intake manifold of the engine in gaseous form. Then, as the throttle 12 is opened, the vacumm pressure differential, in conjunction with the air drawn in through the separator chamber 16, assures that all the liquid fuel will be drawn in spray form through the atomizing unit into the heat exchanger 32 to be passed as a dry vapor to the intake manifold of the engine.

It is the pressure differential created by the Venturi in the mixing chamber 26 in conjunction with the auxiliary air inlet tube 41 which assures a circulation of fuel through the assembly of the invention at all engine speeds; and these elements acting in conjunction with the described construction of the heat exchanger 32 assure that the fuel will be fully and completely vaporized in the heat exchanger at all times.

The heat exchanger 30 uses the heat from the exhaust gases from exhaust manifold 31 to raise the temperature of the liquid fuel from separator 1 6 as it passes through the heat exchanger. The outlet of the heat exchanger 30 is coupled to a fitting 58 to a pipeline 64 which extends to the mixing chamber 26. As mentioned above, the pipeline 24 is also coupled to the mixing chamber 26, and this latter pipeline introduces the air from the separator 1 6 into the mixing chamber.

The heat exchanger 30 is also connected to the exhaust pipe 70 of the internal combustion engine, so that exhaust gases pass from the exhaust manifold 31 through the heat exchanger to the exhaust pipe. A temperature controlled bypass 72 is coupled from the exhaust manifold 31 directly to the exhaust pipe 70, so that after a certain temperature threshold in mixing chamber 26 is reached, the exhaust gases are by-passed around the heat exchanger until the threshold drops to a predetermined lower level.

In the operation of the system, after the fuel is metered and atomized by the carburetor 10, it enters the separator 1 6. When the fuel-air mixture from the carburetor enters the passageway 1 8 to the separator 16, it is drawn into the separator chamber at a high velocity, and the fuel-air mixture strikes against the baffle plate 14, causing the liquid fuel to separate out from the mixture and to run down the baffle plate to the outlet 23 of the separator chamber and through pipeline 20 into the heat exchanger unit 30.

The fuel with about 3%5% of the air, for example, is directed to the heat exchanger to be vaporized therein at a high temperature, whereas the remaining 95%-97% of the air is by-passed at cool ambient temperature through the pipline 24 to the mixing chamber 26. The fuel from the separator 1 6 and, for example, about 3% of the air, are drawn into the heat exchanger 30 to be completely vaporized in the heat exchanger and transformed to a dry vapor state.

The dry vapor fuel from the heat exchanger is then passed through pipline 64 into the mixing chamber 26. The suction pressure of the engine intake manifold 28, to which the mixing chamber is coupled, causes the vaporized fuel to be drawn from the mixing chamber, and also causes the air from the separator chamber 1 6 to be drawn through the pipeline 24 and through the mixing chamber 26. The resulting aspirating effect of the air as it is drawn through a Venturi in the mixing chamber 26 provides an increased suction effect on the fuel passing through the pipeline 64 from the heat exchanger 30. This creates a desired vacuum pressure differential which assures circuiation of the fuel through the system, and prevents any build-up of fuel in any of the components of the system.

The present invention provides, therefore, a fuel vaporizing system for obtaining complete combustion in a gasoline engine and which includes an improved separator for use in the fuel vaporizing system, the separator being simple in its construction, and achieving the desired separation of liquid fuel from the fuel-air mixture from the carburetor by the provision of an inclined baffle plate at the entrance of the separator, against which the incoming fuel-air mixture strikes, causing the liquid fuel to separate and run down the baffle plate into the liquid fuel outlet in the bottom of the separator.

It should be noted that the fuel vaporizing system of the invention permits the use of diesel fuel in gasoline engines. When used with diesel fuel, the engines may be started by winding a battery-energized heating coil around the fuel line, and including a thermostat in the energizing circuit for the coil to de-energize the coil when operating temperature for the diesel fuel is reached.

It will be appreciated that although a particular embodiment of the separator of the invention has been shown and described, modifications may be made. It is intended in the claims to cover the modifications which come within the true spirit and scope of the invention.

Claims (5)

Claims

1. A separator for use with a fuel vaporizing assembly in an internal combustion engine which includes carburetor means for producing a metered mixture of air and atomized fuel, said separator coupled to said carburetor means and having an entrance for receiving the metered mixture of air and atomized fuel therefrom, and for separating the fuel from the air in the mixture, said separator including a baffle plate mounted therein and positioned at the entrance thereof in the path of the mixture of air and atomized fuel from said carburator means to be struck thereby so as to separate the fuel from the air in the mixture and to cause the fuel to run along the baffle plate.

2. The separator as claimed in Claim 1, wherein said baffle plate is mounted in said separator in an inclined position with respect to the path of the air and fuel mixture.

3. The separator as claimed in Claim 2, including fuel outlet means positioned in the bottom thereof adjacent to the lower end of the baffle plate.

4. The separator as claimed in Claim 3, including air outlet means positioned in the top thereof.

5. A separator as claimed in any preceding claim, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.