KR20000016734A - Fuel-air mixture apparatus - Google Patents

Abstract

PURPOSE: A fuel-air mixture apparatus is provided to exist a small amount of not burned or incompletely burned fuel in a discharged gas. CONSTITUTION: Fuel-air mixture apparatus (1) has a body (2) adapted for connection via a flange (3) to an air cleaner housing (3') and to an engine inlet manifold (4'). In the body (2) is arranged a primary air passage (5) having an inlet(6), an adjustable throttle (7), a throat (8) and an outlet (9). The throttle will be connected in use to a speed control device for the engine via a linkage (10). Also provided in the body (2) is a secondary air passage (13) having an inlet (14) from the air cleaner housing and an outlet (15) to the primary air passage (5) at the throat (8). Towards its downstream end, the secondary air passage opens into a chamber (16), with the opening (17) being arranged tangentially to the chamber to induce swirling air flow in the chamber. The outlet (11) is provided axially of the chamber. At the other end of the chamber, in a bore (18) in the body a nozzle device (21) is provided. It has a circumferential void (24) to the body. This void has a fuel supply bore (25) in the body (2) and connected to a continuous fuel pump opening into it. A fuel inlet (26) leads from the void to an internal bore in the sleeve (22). Slidably mounted in the sleeve is a guide (27), sealed to the sleeve via a gland (28). The outside end of the guide carries a compression spring (29) and the end of the guide is closed by a plug (30) providing an abutment for the spring, whereby the guide is urged outwards. The guide has a bore (31) in which a needle (32) is slidably mounted. The arrangement is such that when the plug (30) is pushed fully inwards of the body, as on closure of the throttle, the needle closes the aperture (38) and the fuel supply to the engine, but the force with which the needle is urged into the aperture is regulated by the internal spring (33). In use, the plug (30) is acted on by an abutment member (40), which is movable in step with the throttle (7) via a branch of the linkage (10). The linkage is designed to ensure that the stoichiometrically required amount of fuel is provided for the throttle opening.

Description

Fuel-air mixing device

A fuel-air mixing device, in which fuel is mixed with air before it is introduced into the cylinder of the engine, typically relies on the pressure drop of the throttle in the device to draw fuel into a device known as a vaporizer or when fuel passes through the device. Rely on fuel injection into the air.

In general, conventional devices rely on one stage of the fuel and air mixture and are regulated with respect to droplet size and overall vaporization of the fuel in the air introducing the fuel and air mixture. Inappropriate vaporization and too large droplet sizes result in incomplete combustion of fuel that is not combusted or present in the exhaust gas from the engine.

The invention relates in particular to a fuel-air mixing device of an internal combustion engine.

1 is a side cross-sectional view of a fuel-air mixing device body according to the present invention.

2 is a cross-sectional view taken along the line II-II of FIG. 1 of the mixing chamber in the secondary air passage;

FIG. 3 is a sectional view similar to FIG. 1 of the nozzle device of the fuel-air mixing device shown in a larger view.

4 is a plan view of a secondary fuel-air mixing device according to the present invention.

FIG. 5 is a sectional view similar to FIG. 4 as a variant of the secondary fuel-air mixing device. FIG.

6 is a side cross-sectional view of the throttle in the primary air passage;

7 is a view like that in FIG. 1 of a third fuel-air mixing device according to the invention.

It is an object of the present invention to provide a fuel-air mixing device in which unburned or incompletely burned fuel is present in a small amount of exhaust gas.

The fuel-air mixing device of the present invention is:

Primary air passage with inlet, adjustable throttle and outlet;

A secondary air passage with an outlet and inlet to the primary air passage between the adjustable throttle and the outlet,

And a nozzle for introducing the fuel into the secondary air passage, wherein the fuel is mixed with the air flowing through the secondary air passage before mixing with the air flowing into the primary air passage during use.

It can be seen that the nozzle is a fixed orifice nozzle, but a variable orifice is preferred. In the best embodiment, the nozzle has a needle tapered at its inlet to impart variability by axial movement of the needle. In one embodiment, the needle is a small bead, preferably at its tip, to induce the divergence of the fuel as it flows from the end of the needle or to prevent fuel from flowing into the needle tip and forming a linear drop from the tip. Equipped with a small ball or inverted cone.

Usually, the inlet of the primary air passage will be connected to the air cleaner and the outlet will be connected to the inlet manifold of the internal combustion engine.

The inlet of the secondary air passage may be in the primary air passage between the inlet and the throttle. The inlets of the two air passages may be independent of one another but may also be downstream of the same air cleaner.

In order to induce increased air flow rate within the primary air passage and reduced pressure at the outlet of the secondary air passage for increased air flow within the secondary air passage, the outlet of the secondary air passage is the primary air passage. Is provided on a fixed throttle. In one embodiment, the fixed throttle is provided with a plurality of outlets from the secondary air passage. The secondary air passage has a branch passage surrounding the primary air passage, the outlet being made from the branch passage and spaced around the primary air passage.

In one embodiment, the secondary air passage is provided with a constriction for inducing an increased air flow rate as it passes through the constriction, wherein the nozzle is disposed in the constriction and the fuel is in contact with the air in the region of increased flow rate. Are mixed. The contraction portion is formed as an annular space between the ring and the nozzle or needle at installation. Preferably the ring has upstream and downstream slopes that meet at the edges to induce turbulence.

In another embodiment, a chamber is formed in the secondary air passage and the nozzle is initially arranged to inject fuel into the chamber to mix fuel-air within the chamber. The passageway has shrinkage portions upstream and downstream of the chamber. If at the downstream end, the constriction can be at the outlet from the secondary air passage to the primary air passage.

Preferably, the constriction is configured to induce turbulence in the air flow to the secondary air passageway and increase the mixing of fuel and air by forming a constriction with a pair of inclined surfaces that meet the edges.

Alternatively, a portion of the secondary air passage flow of the chamber approaches the chamber at least in the tangential direction of the flow, inducing a vortex of the air flow within the chamber. In this embodiment, the nozzle is preferably arranged to introduce fuel into the center of the vortex, and the fuel can be emitted from the nozzle for mixing with the air.

The nozzles are arranged such that the fuel out of the orifice impinges on the ultrasonic transducer to break up the fuel into small droplets.

In one embodiment, the linkage is provided for connecting to the adjustment throttle in the primary air passage for nozzle orifice adjustment, and the fuel flow from the nozzle is mixed with the air flow in the two passages.

In another embodiment, the control device is provided for servo control of the nozzle orifice according to engine parameters including the throttle position and the composition of the exhaust gas from the engine, the fuel flow from the nozzle being mixed with the air flow in the two passages. .

It can be seen that the fuel flow from the nozzle is introduced by the reduced pressure at the nozzle, but a pump is usually provided to pump fuel into the nozzle. Preferably, the pump is adapted to deliver fuel to the nozzle at a constant pressure.

It will be appreciated that the fuel may be a gas or a liquid.

Hereinafter, three specific embodiments are described by way of example with reference to the accompanying drawings in order to facilitate understanding of the present invention.

First embodiment

The fuel-air mixing device 1 is adapted to be connected to the air cleaner housing 3 '(only partially shown) via the flange 3 and to the engine inlet manifold 4' via the plug 4. Has (2) The main body 2 is arranged with a primary air passage 5 having an inlet 6, an adjusting throttle 7, a throat 8 and an outlet 9. The throttle will generally be connected via linkage 10 to an engine (not shown) speed control device, typically an accelerator pedal or a governor of an automobile. The throat is installed in the tubular insert 11 and the inner diameter of the throat is selected to match the size of the engine to which the device 1 is fixed. Where the throat is smaller than that shown in FIG. 1, the tubular insert has a top extension that extends farther away, such as the strut 7, and the throttle is provided to cover the butterfly 12.

The body 2 is also provided with a secondary air passage 13 having an inlet 14 from the air cleaner housing and an outlet 15 to the primary air passage 5. This is in the throat 8 and will be described in more detail below. Toward its downstream end, the secondary air passage opens to the chamber 16 and the opening 17 is arranged tangential to the chamber to induce vortex air flow within the chamber. The outlet 14 is provided in the axial direction of the chamber.

At the other end of the chamber, a nozzle arrangement 21 is provided in the bore 18 of the body. The nozzle arrangement comprises a main sleeve 22 with two O-ring grooves 23 for the O-rings 23 'sealing the circumferential voids 24 in the body. This void is connected to a continuous fuel pump (not shown) that has a fuel supply bore 25 in the body 2 and opens to the void. The fuel inlet 26 exits the void and connects to the inner bore in the sleeve 22. The guide 27 is slidably mounted to the sleeve and sealed to the sleeve via the chuck 28. Since the outer end of the guide supports the compression spring 29 and the end of the guide is closed by a plug 30 which abuts the spring, the guide is forced outwards.

The guide has a bore 31 on which the needle 32 is slidably mounted. The spring 33 acts between the plug 30 and the washer 34 acting on the O-ring 34 'against the head 35 of the needle. The latter has a point 36 which supports the small ball 37, which extends through the opening to the standard dimension of the sleeve 22 end.

This arrangement allows the needle to close the opening 38 to supply fuel to the engine when the plug 30 is fully pushed towards the inside of the body, such as when the throttle is closed, but the force that pushes the needle into the opening causes an internal spring. Adjusted by 33.

In general use, the plug 30 is acted upon by the contact member 40 and the contact member 40 is stepwise movable with the throttle 7 through the branch path of the linkage 10. The device is to gradually open the throttle 7 so that the contact member is retracted gradually so that the needle point 36 is retracted from the opening 38. This allows more fuel to flow through the bore 25, the inlet 26 and the opening 38. The linkage is designed to ensure that the theoretically required amount of fuel is supplied to the throttle opening.

Much of the air flowing into the engine flows through the primary air passage 5. A small amount of air flows into the secondary air passage 13. As noted above, this air flow enters the chamber 16 and generates a vortex air flow therein. The fuel leaving the nozzle apparatus 21 on the chamber axis spreads radially in this air stream and mixes with the air. Fuel is induced to leave the needle point 36 in the ball 37 in small droplets, where the ball enhances the evaporation of the fuel. The fuel and air leave the chamber at the constriction 40 in the insert 11, the constriction being formed as a pair of upstream and downstream opposing inclined surfaces 41, 42 defining an edge 43, the edge being fuel When encountering a primary air stream, turbulence is introduced into the secondary air stream. This flow is also turbulent downstream of the throttle 7. The result is a mixture of fuel and air before introduction into the engine. It should be noted that the fuel flows continuously from the nozzle arrangement and first mixes with the secondary air stream and then with the primary air stream.

Second embodiment

Referring again to FIG. 4, in the second embodiment, since the nozzle device 121 is arranged tangentially to the primary air passage 105 and has a simpler configuration, the plug 130 is removed from the stepper motor 151. Is driven by an electronic actuator, which is linearly controllable under the control of the threaded shaft output (not shown) or from the engine operating computer 153, the programming of the engine operating computer being performed by a person skilled in the art. The description thereof is omitted. The computer 153 also controls a second stepper motor 152 coupled to the throttle to adjust the position. In addition to controlling the needle 132 with a computer, this embodiment includes a transducer 154 into which fuel from the needle is introduced into its face 155. This has the effect of decomposing fuel droplets for their vaporization in the swirling secondary air stream. In this respect, this embodiment is similar to the embodiment of FIG.

Modification of the second embodiment

5 and 6 show a variant of the second embodiment, in which the secondary air passage has two branch passages 161, 162 connected to two chambers 163, 164. The first chamber 163 connected to the first branch path is similar to the chamber 16 of the first embodiment, where the needles 165 are housed. The needle extends through a retraction 166 similar to the contact member of the first embodiment, and the needle has a small inverted cone 167 at its end. The cone is installed to provide sharp edges where fuel droplets flow into the air stream through the constriction. The air from the second branch passage 162 is supplied to the second chamber 164. Two secondary air streams meet in the sonde 168 region of the ultrasonic transducer 169. Fuel droplets from the needles collide on the sonde and break up from each other. Fuel mixed secondary air flow exits the second chamber and enters the annular passage 170 behind the fixed throttle insert 171. The insert has two rows of holes 172, 173 spaced apart at an angle around it. The upper of these holes 172 is at the minimum diameter portion of the throttle and directs the secondary air stream through the throttle to the primary air stream. The lower hole 173 is the outlet from the groove 174 on the insert, which is directed downward to discharge fuel liquid that may accumulate therein into the primary air passage 105. Note the longer flow path from the second chamber 164, the holes from this chamber are larger in order to arrange the flow through each of the upper holes 172 as uniform as possible.

Third embodiment

Referring to FIG. 7, the third embodiment shown in FIG. 7 is different from the first and second embodiments that do not have a chamber in the secondary air passage 213. Rather, the nozzle device 221 incorporates a nose 261 mounted with the device in the bore 218 of the body 202. The nose has a transverse inlet 262 for secondary airflow that impinges on the tip 263 of the needle sleeve 222 and is accelerated when the secondary airflow flows through the inclined outlet 264 of the nose. It also has an inclined portion 265 facing the inclined outlet 264 which forms a constriction 266 and causes turbulent flow when secondary air leaves the nose. The constriction is arranged to be the outlet of the secondary air passage. The fuel introduction orifice between the nozzle arrangement 221 and the needle 232 is close to the retraction and the needle actually extends to the retraction. The device induces vaporization of fuel in the secondary air and formation of fine fuel droplets when the fuel is mixed with the primary air stream.

The engine operating computer can thicken the fuel-air mixture to allow it to start in cold conditions, but it should be understood that the thickening is lower than that required by conventional carburetors.

The invention is not intended to be limited by the foregoing detailed description. For example, the engine operating computer may include additional features that allow the device to be properly matched with the type of fuel, the grade of fuel and the driving attitude of the vehicle in which the device is installed.

Claims (26)

Primary air passage with inlet, adjustable throttle and outlet; A secondary air passage with an outlet and inlet to the primary air passage between the adjustable throttle and the outlet, And a nozzle for introducing fuel into the secondary air passage, wherein the fuel is mixed with the air flowing through the secondary air passage before being mixed with the air flowing into the primary air passage during use. The fuel-air mixing device of claim 1, wherein the nozzle is a fixed orifice nozzle. The fuel-air mixing device of claim 1, wherein the nozzle is a variable orifice. 4. The fuel-air mixing device of claim 3 wherein the nozzle has a needle tapered at its inlet to impart variability by axial movement of the needle. 5. The needle according to claim 4, wherein the needle has a small bead, preferably a small ball at its tip, to prevent fuel from flowing into the needle tip and form a linear drop from the tip or to induce the divergence of the fuel when the fuel flows from the end of the needle. Or a fuel-air mixing device with an inverted cone. 6. Fuel-air according to any of the preceding claims, wherein the inlet of the primary air passage is adapted to be connected to an air cleaner and the outlet of the primary air passage is adapted to be connected to the inlet manifold of the internal combustion engine. Mixing device. 7. The fuel-air mixing device of claim 1 wherein the inlet of the secondary air passage is in the primary air passage between the inlet and the throttle. 7. A fuel-air mixing device according to any of the preceding claims, wherein the inlets of the two air passages can be independent of one another but are preferably downstream of the same air cleaner. 9. The secondary air passage of claim 1, wherein the outlet of the secondary air passage is provided in a fixed throttle of the primary air passage, the fixed throttle being increased in air flow rate and secondary in the primary air passage. A fuel-air mixing device inducing a reduced pressure at the outlet of the secondary air passage for increased air flow in the air passage. 10. The fuel-air mixing device of claim 9, wherein the fixed throttle is provided with a plurality of outlets from the secondary air passage. 11. The fuel-air mixing device of claim 10 wherein the secondary air passage has a branch passage surrounding the primary air passage and the outlet is made from the branch passage and spaced about the primary air passage. 12. The secondary air passage according to any one of claims 1 to 11, wherein the secondary air passage is formed with a contraction portion for inducing an increased air flow rate when passing through the contraction portion, wherein the nozzle is disposed in the contraction portion and the fuel is A fuel-air mixing device that mixes with air in areas with increased flow rates. 13. The fuel-air mixing device of claim 12 wherein the retracted portion is formed as an annular space between the ring and the nozzle or needle when installed. 14. The fuel-air mixing device of claim 13 wherein the ring has upstream and downstream inclined surfaces that meet at edges to induce turbulence. 15. A fuel cell as claimed in any preceding claim, wherein a chamber is formed in the secondary air passage and the nozzle is initially arranged to inject fuel into the chamber to mix fuel-air within the chamber. Air mixing device. 16. The fuel-air mixing device of claim 15 wherein the passage has a constriction at the upstream and downstream ends of the chamber. 17. The fuel-air mixing apparatus of claim 16 wherein the retracted portion is at an outlet from the secondary air passage to the primary air passage. 18. The method of claim 16 or 17, wherein the shrinkage portion is configured to induce turbulence in the air flow to the secondary air passageway and increase the mixing of fuel and air by forming a shrinkage portion having a pair of inclined surfaces that meet the edges. Fuel-air mixing device. 19. A fuel-air mixing device according to any one of claims 15 to 18, wherein a portion of the secondary air passage flow of the chamber approaches the chamber at least in the tangential direction of the flow, leading to vortexing of the air flow within the chamber. . 20. The fuel-air mixing device of claim 19, wherein the nozzle is disposed to introduce fuel to the center of the vortex, and the fuel can be emitted from the nozzle for mixing with air. 21. The fuel-air mixing device of claim 20, wherein the nozzle is arranged such that fuel leaving the orifice impinges on the ultrasonic transducer to crush the fuel into small droplets. 22. The linkage according to any one of claims 4 or 5 or 6 to 21, wherein the linkage is provided for connecting to the adjustment throttle in the primary air passage for nozzle orifice adjustment and the fuel flow from the nozzle A fuel-air mixing device mixed with air flow in two passages. 22. An engine parameter according to any one of claims 4 or 5 or 4 or 5, wherein the control device comprises an engine parameter comprising a throttle position and a composition of the exhaust gas from the engine. And a fuel flow from the nozzle is mixed with the air flow in the two passages. 24. A fuel-air mixing device according to any one of the preceding claims wherein the device is adapted and arranged such that fuel flow from the nozzle is introduced by the reduced pressure at the nozzle. 24. A fuel-air mixing device according to any one of the preceding claims wherein a pump provided for pumping fuel into the nozzle is combined. 27. The fuel-air mixing device of claim 25 wherein the pump is adapted to direct fuel to the nozzle at a constant pressure.