GB2093910A - Internal combustion engine fuel feed vaporizing system - Google Patents

Abstract

An internal combustion engine feed system comprises an inlet pipe (1) accommodating a throttle (2) and a surface vaporizing element (3) having a heat-supply section (16), and a fuel-supply device (4) associated with a fuel-metering unit (12). The fuel-supply device (4) is provided with a means (7) adapted for delivering fuel in the form of a film to the surface vaporizing element (3) and arranged at an end (5) thereof. The heat-supply section (16) is located on the opposite end (17) of the surface vaporizing element (3). <IMAGE>

Description

SPECIFICATION Internal combustion engine feed system The present invention relates to the engine engineering, and more particularly to internal combustion engine feed systems.

The system can be used for feeding petrol engines of various vehicles.

The present invention can be most advantageously used for large petrol engines installed on vehicles used mainly in big towns.

This is determined by the fact that one of the advantages of the present system is a marked decrease of the exhaust emission toxicity.

The present invention provides an internal combustion engine feed system comprising an inlet pipe fitted with a throttle and with a surface vaporizing element having a heat-supply section, and a fuel-supply device associated with a fuelmetering device, wherein, according to the invention, the fuel-supply device contains a means adapted for delivering the fuel in the form of a film to the surface vaporizing element and located at one end thereof, the heat-supply section being arranged at its opposite end.

In the feed system of the present invention the fuel is supplied in the form of the film to the surface vaporizing element at one end thereof, while the heating of the vaporizing element is performed at the opposite end thereof. This fully protects the air flow passing through the inlet pipe into the engine cylinders from the unvaporized fuel droplets getting into it, a temperature field with a gradual temperature rise being formed along the length of the surface vaporizing element as directed from the fuel supply area toward the heated end thereof. Over the entire length of the droplet travel the temperature varies within boiling temperatures of fuel fractions, whereby the fuel overheating involving raising the temperature up to carbonization temperatures is made impossible.

In this case, the fuel vaporization proceeds at a high speed determined by much higher values of the vaporizing element -- fuel heat transfer ratio, than usual practice. This is achieved by the fact that the temperature at which each fuel fraction vaporizes is close to its boiling temperature, this condition being automatically maintained in case the operating duty is changed over, thus causing a change in the amount of the fuel supplied as well as in the exhaust gas parameters.

It is also desirable that the means for delivering fuel in the form of the film to the surface vaporizing element be provided as an annular chamber embracing the inlet pipe and communicated with the interior cavity thereof through an annular slot provided in the inlet pipe wall.

This assures the uniform spreading of the fuel in the form of the film upon the surface of the vaporizing element, the said means being extremely simple in design.

It is also desirable tht the means for delivering the fuel in the form of the film be made as an impeller mounted within the inlet pipe and having fuel-supply ducts provided in the blades and the shaft thereof.

This provides high degree of uniformity of spreading the fuel in the form of the film over the surface of the vaporizing element, thus making it possible to shorten the length thereof.

It is desirable that the end of the surface vaporizing element with the heat-supply section located thereon be provided with ribs for increasing the heat-receiving surface thereof.

This contributes to a more intensive process of supplying heat to the surface vaporizing element, thus resulting in a shorten length of the heatsupply section.

It is also desirable that the throttle be arranged directly after the end of the surface vaporizing element, which has the heat-supply section provided thereon.

Due to this arrangement the throttle turbulates the fuel-air mixture, thus resulting in the homogeneous composition thereof across the inlet pipe section.

The invention will now be explained in greater detail with reference to specific embodiments, taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a sectional view schematically illustrating an internal combustion engine feed system according to the invention and taken longitudinally along the inlet pipe; FIG. 2 is a sectional view of another embodiment of the internal combustion engine feed system according to the invention, taken longitudinally along the inlet pipe; and FIG. 3 is an enlarged view of an embodiment of the surface vaporizing element.

The internal combustion engine feed system comprises an inlet pipe 1 (FIG. 1) fitted with a throttle 2 and with a surface vaporizing element 3.

A fuel-supply device 4 is arranged at an end 5 of the surface vaporizing element 3 and is provided with electro-magnetic fuel-metering devices 6 as well as a means 7 adapted for delivering the fuel in the form of a film 8 onto the surface vaporizing element 3. A duct 9 communicates the electromagnetic fuel-metering devices 6 with a fuel pump 10 and a fuel tank 1 The electro-magnetic fuel-metering devices are controlled by a conventional electronic fuel metering unit 1 2 having its input connected to engine operating duty sensors 13. The means 7 is an annular chamber 14 embracing the inlet pipe 1 and communicated with the end 5 of the surface vaporizing element 3 through an annular slot 1 5 provided in the inlet pipe wall.A heat-supply section 16 is located near an end 1 7 of the surface vaporizing element 3, which is opposite to the end 5. Exhaust gases passing through the outlet pipe (not shown) give up their latent heat. The throttle 2 is located directly after the end 1 7 of the surface vaporizing element 3. However, the throttle 2 may be positioned before the fuel-supply device 4 as well, which is indicated by the dash line in the drawing.

FIG. 2 is a view of another embodiment of the means 7 for delivering the fuel in the form of the film 8 to the surface vaporizing element 3.

Said means 7 is an impeller 1 8 comprising blades 19 fixed on a shaft 20. The shaft 20 of the impeller 1 8 is supported in bearings 21 of the hub 22 of a connecting strap 23. The connecting strap 23 is located in the inlet pipe 1 in such a manner that the blades 19 of the impeller 18 are on the level of the end 5 of the surface vaporizing element 3. Through ports 24 are provided in the blades 19, the ports 24 being in communication with the electronic metering devices 6 via a part 25 made in the shaft 20 and ports 26 made in the connecting strap 23.

The heat-supply section 1 6 located at the end 17 of the surface vaporizing element 3 may have an even surface (as shown in FIGS. 1 and 2). But it may have ribs 27 (FIG. 3) serving to increase the heat-receiving area of the section 1 6.

This contributes to a more intensive process of supplying heat to the surface vaporizing element 3, thus resulting in a shorter length of the heatsupply section 1 6. To attain the maximum efficiency of the proposed feed system the vaporizing element 3 must be made of a high heat conductivity material, e.g. copper.

The proposed internal combustion engine feed system operates as follows.

With the engine in operation, the fuel (FIG. 1) is forced from the fuel tank 11 to the electromagnetic fuel-metering devices 6 by means of the fuel pump 10 via the duct 9. The electro-magnetic fuel-metering devices 6 have their out!ets being in communication with the annular chamber 14 associated with the end 5 of the surface vaporizing element 3 via the annular slot 1 5 provided in the wall of the inlet pipe 1. At the same time, due to the throttle being open, the air enters the inlet pipe 1. The fuel supply control is accomplished by means of varying the duration of the driving pulses received from the electronic metering unit 12, the shaping of the said pulses being performed depending upon the signals from the engine operating duty sensors 13.The metered amount of the fuel enters the annular chamber 14 wherefrom it passes through the annular slot 1 5 to the end 5 of the surface vaporizing element 3, and, being acted upon by the air flow and surface tension forces, spreads over the surface thereof in the form of the film 8.

As heat to the surface vaporizing element 3 is supplied on the section 1 6 arranged at the end 17 opposite to the location of the means 7, the heat flow from the heat-supply section 16 spreads over the surface vaporizing element 3 against the spreading of the fuel film 8. In this case, a building-up temperature field is produced in the surface vaporizing element 3 which results in heating and vaporizing of the moving fuel film 8 in accordance with the fuel fractional distillation curve. At a preset temperature of the fuel-supply section 1 6 of the surface vaporizing element 3 each fraction of the fuel moving in the form of the film 8, being gradually heated, finally reaches a zone providing most favourable conditions for vaporizing thereof, i.e. the zone wherein the temperature of the surface vaporizing element 3 is near the boiling temperature of the fraction in question.The wide range temperature field produced in the surface vaporizing element 3, as well as the rapid increase of the heat-exchange coefficient resulting from the thinning of the fuel film 8 due to spreading and vaporizing thereof, automatically provide the setting-up of the vaporization zone for each fuel fraction in that very spot where the heat exchange conditions are at their optimum. Therefore, no temperature control of the surface vaporizing element 3 is required at all operating duties of the engine. The fuel vapours thus obtained, get mixed with the air, thus forming the homogeneous fuel-air mixture of controlled composition.The arrangement of the throttle 2 in the inlet pipe 1 directly after the end 1 7 of the surface vaporizing element 3 performs the tu rbulation of the fuel-air mixture flow, thus producing the homogeneous composition across the inlet pipe 1.

The internal combustion engine feed system in accordance with the embodiment depicted in FIG.

2 operates as follows.

With the engine in operation, the throttle 2 is open, and the air flow passes via the inlet pipe 1 into the engine cylinders. In the course of its travel the air flow streams over the blades 19 of the impeller i 8, thus causing the latter to rotate. The more is the air consumption, i.e. the more open is the throttle 2, the higher is the rotation speed-of the impeller 1 8, and vice versa. At the same time with the air supply the metered amount of fuel is delivered into the engine cylinders by the electromagnetic metering devices 6.Via the ducts 26 in the connecting strap 23, the duct 25 in the shaft 20 of the impeller 18 the fuel passes into the ducts 24 cf the impeller blades 1 9. From the ducts 24 the fuel flows to the end 5 of the surface vaporizing element 3 and spreads over its surface in the form of the film 8. The impeller 1 8 provides a hig' degree of uniformity when spreading the fuel fi!m 8 over the surface vaporizing element 3, thus making it possible to shorten the length thereof. The vaporization of the fuel film 8 is accomplished in a manner similar to that in the embodiment of the system described above.

While particular embodiments of the invention have been shown and described, various modifications thereof will be apparent to those skilled in the art and therefore it is not intended that the invention be limited to the disclosed embodiments or to the details thereof and the departures may be made therefrom within the spirit and scope of the invention as defined herein.

The present invention prevents the thermal decomposition of the fuel in the process of vaporization thereof and eliminates the possibility of the unvaporized fuel in the liquid phase getting into the engine cylinders. The system provides the complete vaporization of the liquid fuel and a thorough mixing thereof with the air at all operating duties of the engine, no special temperature control of the surface vaporizing element being necessary. The system provides the homogenity of the fuel-air mixture entering the engine cylinders in all operating duties of the engine.

The system provides: - high efficiency of the fuel combustion process on account of only the vapour phase of the fuel present in the cylinders; - marked decrease of the exhaust emission toxicity in all pollutant components thereof, and improvement of the economic parameters of the engine; - reduction of the non-uniformity of the fuelair mixture between cylinders and from cycle to cycle; - the decrease of the engine parts wear arising from outwash of the oil from the cylinder walls by unvaporized fuel.

Claims (6)

1. An internal combustion engine feed system comprising an inlet pipe provided with a throttle and with a surface vaporizing element having a heat-supply section, a fuel-supply device associated with a fuel-metering unit, the fuelsupply device being provided with a means adapted for delivering fuel in the form of a film to the surface vaporizing element and arranged at one end thereof, and the heat-supply section supplying heat to the surface vaporizing element being arranged on the opposite end thereof.

2. An internal combustion engine feed system according to Claim 1, wherein the means for delivering fuel in the form of a film to the surface vaporizing element is an annular chamber embracing the inlet pipe and communicated with its interior cavity through an annular slot provided in the inlet pipe wall.

3. An internal combustion engine feed system according to Claim 1, wherein the means for delivering fuel in the form of a film to the surface vaporizing element is an impeller mounted in the inlet pipe and having fuel ducts provided in the impeller blades and shaft.

4. An internal combustion engine feed system according to any of Claims 1 through 3, wherein the end of the surface vaporizing element, on which the heat-supply section is arranged, is provided with ribs for increasing its heat-receiving surface.

5. An internal combustion engine feed system according to any of Claims 1 through 4, wherein the throttle is arranged immediately after that end of the surface vaporizing element, on which the heat-supply section is located.

6. An internal combustion engine feed system substantially as hereinbefore described with reference to the accompanying drawings.