KR100534187B1 - Fuel-Air Mixer - Google Patents

Abstract

The fuel-air mixing device 1 has a body 2 adapted to be connected to the air cleaner housing 3 'and the engine inlet manifold 4' via the flange 3. The main body 2 is arranged with a primary air passage 5 having an inlet 6, an adjustable throttle 7, a throat 8 and an outlet 9. When in use, the throttle will be connected to the engine's speed control via a connection 10. The body 2 is also provided with an inlet 14 from the air cleaner housing and an outlet 15 for the primary air passage 5 in the throat 8. Towards the downstream end, a secondary air passage opens to the chamber 16 and the opening 17 is disposed tangentially to the chamber to induce vortex air flow within the chamber. The outlet 15 is installed in the axial direction of the chamber. At the end of the chamber, a nozzle arrangement 21 is provided in the bore 18 of the body. It has a circumferential void 24 in the body. This void has a fuel supply bore 25 in the body 2 and is connected to a continuous fuel pump which opens therein. The fuel inlet 26 is connected from the void to the inner bore of the sleeve 22. A guide 27 is slidably mounted to the sleeve and sealed to the sleeve via the chuck 28. The outer end of the guide supports the compression spring 29 and the end of the guide is closed by a plug 30 that contacts the spring, and the guide is pressed outward. The guide has a bore 31 and a needle 32 is slidably mounted in the bore. When the plug 30 is fully pushed into the body, the device closes the opening 38 and the fuel is supplied to the engine, as in the closing of the throttle, but the force that presses the needle into the opening causes an internal spring. Adjusted by 33. In use, the plug 30 is acted upon by the contact member 4, wherein the contact member can move stepwise with the throttle 7 through the branch path of the connection 10. The connection is designed so that the theoretical amount of fuel required is provided in the throttle opening.

Description

Fuel-air mixing device

The invention relates in particular to a fuel-air mixing device for internal combustion engines.

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 a pressure drop in the throttle of the device to draw fuel into the device, known as a carburettor, Rely on fuel injection into the air as it passes.

In general, conventional devices rely on one stage of fuel and air mixture and are regulated with respect to droplet size and overall vaporization of 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.

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

2 is a cross sectional view along 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 cross sectional view showing a 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 which implements a small amount of unburned or incompletely burned fuel in the exhaust gas.

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

A primary air passage with inlet, adjustable throttle and outlet,

A secondary air passage having an outlet and an inlet for the primary air passage between the adjustable throttle and the outlet,

It includes a nozzle into which the fuel is introduced into the secondary air passageway, whereby the fuel is mixed with the air flowing through the secondary air passageway before being mixed with the air flowing into the primary air passageway during use.

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

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 reduce the pressure at the outlet of the secondary air passage in order to increase the air flow rate in the primary air passage and increase the air flow in the secondary air passage, the outlet of the secondary air passage is fixed to the primary air passage. Is provided in the throat. In one embodiment, the fixed throat is provided with a plurality of outlets from the secondary air passage. The secondary air passage has a branch path surrounding the primary air passage, the outlet being formed from the branch path and spaced around the primary air passage.

In one embodiment, the secondary air passage is formed with a shrinkage for increasing the air induction rate as it passes through the shrinkage, wherein the nozzle is disposed in the shrinkage and the fuel is mixed with air in the region of increased flow rate. . The shrinkage may be formed as an annular space between the ring and the nozzle or the needle. 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 generate turbulence in the air flow to the secondary air passageway and improve 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, creating a vortex of air flow within the chamber. In this embodiment, the nozzle is preferably arranged to introduce fuel into the center of the vortex, from which fuel can be emitted from the nozzle for mixing with the air.

In one embodiment, the nozzles are arranged such that the fuel leaving the orifice impinges on the ultrasonic transducer to crush the fuel into small droplets.

In one embodiment, a connection is provided to connect to an adjustable throttle in the primary air passage for adjustment of the nozzle orifice, whereby 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 in accordance with engine parameters, including the throttle position and / or the composition of the exhaust gas from the engine, whereby the fuel flow from the nozzle is in the two passages. Mixed with air flow.

While it can be expected that the fuel flow from the nozzle is caused by the pressure drop in the device at the nozzle, a pump is generally provided for pumping fuel into the nozzle. Preferably, the pump is configured to deliver fuel to the nozzle at a constant pressure.

It can be expected that the fuel can 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 connected to the air cleaner housing 3 '(only partially shown) via the flange 3 and through the spigot 4 to the engine inlet manifold 4' (only partially). It has a body (2) configured to be connected to). The main body 2 is arranged with a primary air passage 5 with an inlet 6, an adjustable throttle 7, a throat 8 and an outlet 9. The throttle will generally be connected via a connection 10 to an engine (not shown) speed control device, typically an accelerator pedal or a governor of an automobile. The throat is installed in a 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 an upper extension extending as far as the strut 7, which is provided so that the butterfly 12 is encased.

The body 2 is also provided with a secondary air passage 13 having an outlet 15 for the primary air passage 5 and an inlet 14 from the air cleaner housing. This is in the throat 8 and will be described in more detail below. Toward its downstream end, a secondary air passage opens into the chamber 16 and the opening 17 is arranged tangential to the chamber to generate a vortex air flow in 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 having two O-ring grooves 23 for the O-rings 23 'sealing the circumferential voids 24 of the body. This void has a fuel supply bore 25 in the body 2 and is connected to a continuous fuel pump (not shown) which opens to the void. The fuel inlet 26 exits the void and is guided to the inner bore in the sleeve 22. A guide 27 is slidably mounted to the sleeve and sealed to the sleeve via a gland 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 in contact with 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 washer 34 and the plug 30 acting on the O-ring 34 'in contact with the head of the needle. The latter has a tip 36 extending through an opening to fit the standard dimension of the end of the sleeve 22 supporting the small ball 37. Such a device has a needle closing the opening 38 to supply fuel to the engine when the plug 30 is fully pushed toward the inside of the body, but the force that presses the needle into the opening causes the internal spring ( 33).

In use, the plug 30 is acted upon by the contact member 40 which is stepwise movable with the throttle 7 through the branch path of the connection 10. The device is configured to retract the needle tip 36 from the opening 38 by gradually retracting the contact member when the throttle 7 is gradually opened. This allows more fuel to flow through the bore 25, the inlet 26 and the opening 38. The connection is designed so that the theoretically required amount of fuel is supplied to the throttle opening.

Much of the air entering 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 diffuses radially in this air flow and mixes with the air. The fuel is directed to leave the needle tip 36 in the form of droplets that can enhance the evaporation of the fuel in the ball 37. The fuel and air leave the chamber at the constriction 40 in the insert 11, and The constriction is formed as a pair of upstream and downstream opposed inclined surfaces 41, 42 that define an edge 43 that generates turbulence in the secondary air flow when the fuel meets the primary air flow. This flow is also turbulent downstream of the throttle 7. The result is a mixture of fuel and air before being introduced into the engine. It should be noted that the fuel flows continuously from the nozzle arrangement, firstly mixed with the secondary air flow and then with the primary air flow.

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. Driven by an electromagnetic actuator, which is linearly controllable by a threaded shaft output (not shown) or under control from the engine operating computer 153, the programming of the engine operating computer is available to those skilled in the art. The description thereof will be omitted since it can be performed by. The computer 153 also controls a second stepper motor 152 coupled to the throttle to adjust the position. In addition to computer controlled needle 132, the present embodiment includes a transducer 154 where fuel from the needle is introduced towards face 155. This has the effect of dispersing fuel droplets for their vaporization in the swirling secondary air flow. 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 passages have two branch passages 161, 162 where they are guided to two chambers 163, 164. The first chamber 163 through which the first branch path 161 is guided is similar to the chamber 16 of the first embodiment in that the first chamber 163 houses the needle 165, the needle being the contact member 40 of the first embodiment. And extends through the contraction 166, which 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 perforations 172 and 173 spaced equidistantly around it. The upper perforation 172 of these is at the minimum diameter portion of the throttle and directs the secondary air flow through the throttle to the primary air flow. Lower perforation 173 is the outlet from groove 174 behind the insert, which is directed downward to discharge fuel liquid that may accumulate therein into primary air passage 105. In view of the longer flow path from the second chamber 164, the perforations from this chamber are larger to place the flow through each of the upper perforations 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 impingement of secondary air flow over the tip 263 of the needle sleeve 222 and is accelerated when the secondary air flow flows through the tapered outlet 264 of the nose. It further has a taper 265 facing the tapered outlet 264 which forms a constriction 266, causing the secondary air to become turbulent when leaving 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, with the needle actually extending into the retraction. The device vaporizes fuel in secondary air and forms fine fuel droplets when the fuel is mixed with the primary air flow.

The engine operating computer may enrich the fuel-air mixture to allow it to start up in a cold state, but it should be understood that the richness is lower than that required by a conventional carburetor.

The invention is not limited by the detailed description of the invention described above. For example, the engine operating computer may include additional features that allow the device to be properly matched according to the type of fuel, the grade of the fuel and the driving attitude of the vehicle in which the device is installed. In addition, the present invention can be applied differently from the internal combustion engine. For example, it can be used in boilers.

Claims (24)

A primary air passage (5) having an inlet (6), an adjusting throttle (7) for controlling air flow in the primary air passage and an outlet (9); A secondary air passage 13 having an outlet 15 and an inlet 14 for the primary air passage between the adjustable throttle and the outlet; And A fuel-air mixing device comprising a nozzle 21 opening into a secondary air passage for introducing fuel, Arranged coaxially with a nozzle having a small diameter tip 36 extending at least normally from the orifice into the secondary air passage, to provide variability of the orifice of the nozzle and to control fuel flow through the nozzle An axially movable needle; Further includes a mechanical connection 10 connecting the position of the needle 32 directly to the position of the adjustable throttle 7 of the primary air passage for adjustment of the orifice of the nozzle, During use, the fuel flow from the nozzle matches the position of the adjustable throttle, and the fuel flowing from the orifice toward the small diameter end of the needle mixes with the air flowing through the secondary air passage before mixing with the air flowing into the primary air passage. A fuel-air mixing device configured to be. The method of claim 1, The needle has a small bead 37, a small ball, or reversal at its tip to prevent fuel flow to the tip of the needle and the formation of a linear drop from the tip, or to induce the divergence of fuel when the fuel flows from the end of the needle. Air-fuel mixing device having a cone. The method according to claim 1 or 2, The inlet of the primary air passage is configured to be connected to an air cleaner (3 ') and the outlet of the primary air passage is configured to allow the internal combustion engine to be connected to the inlet manifold (4'). The method according to claim 1 or 2, The inlet (14) of the secondary air passage is formed from the primary air passage between the inlet and the throttle. The method according to claim 1 or 2, The inlet (4,14) of the two air passages may be independent of each other, but located downstream of the same air cleaner. The method according to claim 1 or 2, The outlet of the secondary air passage is provided in a fixed throat 8 of the primary air passage, which fixes the air flow rate in the primary air passage and increases the air flow in the secondary air passage. To reduce the pressure at the outlet of the secondary air passage. The method of claim 6, The fixed throat (8) is provided with a plurality of outlets (172) from the secondary air passages. The method of claim 7, wherein Said secondary air passage having an atmosphere (170) surrounding said primary air passage, said outlet formed from a branch passage and spaced around said primary air passage. The method according to claim 1 or 2, The secondary air passage has a constriction 38 for increasing the air flow rate as it passes through, and the nozzle is disposed in the constriction, whereby the fuel is mixed with air in the region where the flow rate is increased. -Air mixing device. The method of claim 9, And the constriction is formed as an annular space between the ring and the nozzle or needle. The method of claim 10, Said ring having upstream and downstream bevels that meet at an edge to induce turbulence. The method according to claim 1 or 2, The secondary air passage has a chamber (16) and the nozzle is arranged to inject fuel into the chamber to initially mix fuel-air within the chamber. The method of claim 12, And the passageway has a constriction at an upstream or downstream end of the chamber. The method of claim 13, The contraction portion is located at an outlet from the secondary air passage to the primary air passage. The method according to claim 13 or 14, The contraction portion being configured to generate turbulence in the air flow in the secondary air passage so as to increase the mixing of fuel and air by forming a contraction portion having a pair of inclined surfaces 41 and 42 that meet the edges; Air mixing device. The method of claim 15, And a portion of the chamber upstream of the secondary air passage approaches the chamber at least in the tangential direction of the flow, inducing a swirl of air flow within the chamber. The method of claim 16, And the nozzle is arranged to introduce fuel at the center of the vortex, from which fuel can be spun for mixing with air. The method of claim 17, The nozzle is arranged to cause fuel out of the orifice to impinge on the ultrasonic transducer (154) to crush the fuel into small droplets. The method according to claim 1 or 2, The apparatus is configured and arranged to cause fuel flow from the nozzle to occur by pressure reduction at the nozzle. The method according to claim 1 or 2, A sleeve 22 opening into the secondary air passage and providing a nozzle with a bore; A guide 27 movably mounted to the bore, having a bore on its own, and the needle movably mounted; Pedestal 35 between the sleeve and the needle for limiting the size of the needle from the sleeve toward the secondary air passage; And A spring 33 for urging a needle against the pedestal outwardly from the nozzle, Upon closing of the throttle, the needle closes the nozzle with a finite force provided by a spring, and upon opening of the throttle, the needle and sleeve are in contact, whereby the needle and sleeve are positioned at the position of the throttle And a fuel-air mixing device that moves together to retract the needle from the nozzle as needed to coincide with it. The method according to claim 1 or 2, A fuel-air mixing device coupled with a provided pump to pump fuel into the nozzle. The method of claim 21, The pump is configured to deliver fuel to the nozzle at a constant pressure. The method of claim 1, The needle prevents the formation of a linear drop from the tip and fuel flow to the tip of the needle, and a small bead 37, a small ball or reversal at the tip to induce the divergence of the fuel as the fuel flows from the end of the needle. Air-fuel mixing device having a cone. The method of claim 12, And the passageway has a constriction at the upstream and downstream ends of the chamber.