JP3926894B2 - Vaporizer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carburetor used for supplying fuel to an engine, and more particularly to a carburetor having an electromagnetically driven shut-off valve that closes a fuel passage when a key switch is turned off to stop the engine.
[0002]
[Prior art]
In a carburetor installed in the intake line of the engine and sucking fuel into the intake line by engine intake negative pressure and supplying it to the engine, fuel continues to be supplied even after the key switch is turned off and the engine continues to rotate It is widely known to have means for preventing the Gisele phenomenon.
[0003]
As is known from Japanese Patent Application Laid-Open No. Sho 55-62034, many of the measures against diesel fueling prevent the fuel from being sucked from the idle port by shutting off the fuel using an electromagnetic valve, or downstream of the throttle valve. By introducing air and lowering the negative suction pressure of the engine, fuel suction from the idle port is prevented.
[0004]
It is also known to prevent fuel from being sucked from an idle port or a main nozzle by closing a main fuel passage using an electromagnetic valve when the key switch is turned off.
[0005]
For example, Japanese Utility Model Publication No. 52-21404 discloses a technique for providing a solenoid valve that opens and closes an inlet portion of a main fuel passage from a float type constant fuel chamber to a main nozzle, and controls the fuel flow rate according to the engine operating state. This suggests that the main fuel passage can be closed when the engine is stopped, thus preventing the dieseling phenomenon.
[0006]
FIG. 8 shows a conventional carburetor in which an electromagnetically driven shut-off valve is installed at the inlet portion of the main fuel passage, and when the key switch is turned off, the shut-off valve closes the main fuel passage to prevent the dieseling phenomenon. It is the figure which showed the example, This is the twin-boiler carburetor provided with one constant fuel chamber and two intake passages used for the fuel supply of a two-cylinder engine.
[0007]
Referring to FIG. 8, two intake passages 73, 73 extend in the horizontal direction in parallel with each other above the floating constant fuel chamber 72, and a block member 74 protruding downward from the lower surface of the carburetor main body 71 is formed. Built in the center of the constant fuel chamber 72. A main jet 75 is installed laterally below the block member 74, and the fuel in the constant fuel chamber 72 that enters the valve passage 76 extending in the vertical direction from the main jet 75 is supplied to the two main passages for the two intake passages 73, 73. The fuel is sent to the main nozzles 78 and 78 through the fuel passages 77 and 77.
[0008]
The main fuel passages 77 and 77 extend in the vertical direction from the block member 74 to the carburetor main body 71 in parallel with each other, and the low speed fuel passages 79 and 79 branch from near the lower ends thereof. The lower end of the block member 74 is fixed to the valve body 82 of the shutoff valve 81 fixed to the bottom of the bowl-shaped fuel container 80 forming the constant fuel chamber 72, and the main jet 75 is connected to the valve body 82. Installed.
[0009]
The shut-off valve 81 is electromagnetically driven, and the valve body 85 at the tip of the plunger 84 that retreats when the solenoid actuator 83 is energized and moves forward when the solenoid actuator 83 is de-energized cooperates with the valve seat 86 of the valve passage 76 to main fuel passages 77, 77. And the constant fuel chamber 72 are communicated or blocked.
[0010]
[Problems to be solved by the invention]
The actuator 83 is fixedly protruded and fixed to the bottom of the fuel container 80 by screwing the valve body 82 through the fuel container 80 with the mounting cylinder 87 passing through the fuel container 80. , 77 is seated on the valve seat 86 so that the valve body 85 is completely closed, and the plunger 84 is swingable and loosely penetrates the through-hole 88 of the cylinder 87, so that the valve body 85 and the valve seat 86 are connected to each other. Even if it is eccentric, it can be seated on the entire circumference.
[0011]
The actuator 83 is energized when the engine is in operation, sucks the plunger 84 and holds it in the retracted position, and feeds fuel in the constant fuel chamber 72 from the valve passage 76 to the main fuel passages 77 and 77 and the low speed fuel passages 79 and 79. Send to. At this time, the behavior that a part of the fuel flows into the gap between the through-hole 88 and the plunger 84 and then flows out from this is repeated.
[0012]
On the other hand, the actuator 83 generates heat by energization when sucking the plunger 84, and the fuel flowing into the gap is evaporated by this heat to generate bubbles. This bubble has a considerable size, and ascends as it is from the valve passage 76 to the main fuel passages 77 and 77 and the low-speed fuel passages 79 and 79, and acts as a resistance to the fuel flow in these passages to reduce the fuel flow rate. Let Further, intermittently generated bubbles irregularly flow out from the main nozzles 78, 78 and the like into the intake passages 73, 73, discontinuing the suction of fuel, and the air-fuel mixture supplied to the engine is diluted thereby causing engine operation. May be upset.
[0013]
The present invention provides an electromagnetically driven shut-off valve that closes the main fuel passage when the engine key switch is turned off at the entrance of the main fuel passage that feeds fuel in the constant fuel chamber to the main nozzle. It has a valve body provided at the tip of the plunger that moves backward when the actuator is excited and moves forward when it is not excited, and a valve seat that is provided at the inlet portion. There is a carburetor equipped with measures to prevent jellyling, which is configured to loosely penetrate the through-hole, and the gas mixture may be diluted when the engine is operating to dilute the air-fuel mixture and cause the engine to malfunction. It was invented for the purpose of eliminating the disadvantages.
[0014]
[Means for Solving the Problems]
That is, according to the present invention, the plunger is provided with a closing member that closes the open end to the entrance portion of the gap with the plunger of the through hole when the actuator is excited.
[0015]
When the engine is in operation, the actuator is energized, sucks the plunger and holds it in the retracted position, and at the same time, the closing member closes the open end of the gap so that fuel does not flow into the gap. In addition, even if large bubbles are generated inside the gap, the release to the main fuel passage is prevented, and the problem of diluting the air-fuel mixture and causing the engine to malfunction is eliminated.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a twin-boiler carburetor used for supplying fuel to an outboard motor or a stationary two-cylinder engine will be described with reference to the drawings.
[0017]
The twin-boiler carburetor has one constant fuel chamber and two intake passages. Particularly, a double-bottle side flow carburetor in which the intake passages extend in the horizontal direction in parallel with each other is disclosed in, for example, US Pat. It has been known for a long time as disclosed in US Pat. No. 3,188,060. Further, this carburetor can be used for a two-cylinder engine without considering fuel distribution to each fuel chamber.
[0018]
1 to 5, a bowl-shaped fuel container 3 is liquid-tightly attached to the lower surface of a carburetor main body 1 in which two intake passages 2 and 2 are formed in parallel and in a horizontal direction. A constant fuel chamber 6 having a built-in floating element 5 is formed.
[0019]
The two intake passages 2, 2 form an inlet passage portion 7 common to the inlet portion of the air sucked into the engine, and the inlet passage portion 7 is provided with one choke valve 8. Further, a venturi 10 and a throttle valve 11 are provided in each intake passage 2 and 2 downstream thereof, and the choke valve 8 and the two throttle valves 11 each have a single choke valve shaft 9 penetrating the carburetor body 1 and a throttle. It is attached to the valve shaft 12 and opens and closes simultaneously.
[0020]
In the central portion of the constant fuel chamber 6, a prismatic block member 14 is built in which the upper end surface is overlapped with the lower surface of the carburetor main body 1 and is detachably fixed by a set screw 13. Further, the upper end portion of the valve body 49 of the shutoff valve 41 is fitted into a recess 14 a formed at the lower end portion of the block member 14.
[0021]
On the other hand, a prismatic block piece 16 is inserted in the inlet passage portion 7 between the two intake passages 2 and 2. The block piece 16 has a bracket 16a projecting in a right-angle direction at the back end, and a set screw 17 inserted through the bracket 16a is connected to the inlets of the two intake passages 2 and 2, that is, the venturis 10 and 10. The block piece 16 is detachably fixed to the carburetor body 1 by being screwed into the carburetor body 1 near the inlet.
[0022]
Two main fuel passages 19, 19 for the two intake passages 2, 2 are vertically parallel to each other from the lower end portion of the block member 14 to the portion between the two intake passages 2, 2 of the carburetor body 1. It is formed in the direction. The lower ends of the main fuel passages 19 and 19 are open to the recess 14a, and the emulsion tubes 20 and 20 are inserted from the upper end portion to the lower end portion so that almost the whole is made into the emulsion chambers 19a and 19a.
Horizontal passage portions 19b and 19b extending in the horizontal direction from the upper end portions of the emulsion chambers 19a and 19a are provided from the vaporizer body 1 to the bracket 16a. The horizontal passage portions 19b and 19b are main nozzles fixed to the bracket 16a. 21 and 21 are connected to form part of the main fuel passages 19 and 19. The main nozzles 21 and 21 protrude from the narrowest portions of the two venturis 10 and 10, respectively.
[0024]
Further, from the bottom of the emulsion chambers 19a and 19a, which are vertical passage portions of the two main fuel passages 19 and 19, low speeds for the respective intake passages 2 and 2 to which the main fuel from the main fuel passages 19 and 19 is supplied. The fuel passages 23 and 23 are branched. The two low-speed fuel passages 23 and 23 extend from the lower end portion of the block member 14 in the vertical direction in parallel with the emulsion chambers 19a and 19a, and the vertical passage portions 23a and 23a having the upper end opened on the upper surface of the vaporizer body 1; It consists of groove-like lateral passage portions 23b, 23b that extend in the direction of the outlet of the intake passages 2, 2 along the upper surface of the main body 1 and reach the port chambers 23c, 23c. An idle port 25 and a slow port 26 are provided toward 2.
[0025]
A low speed jet 24 is provided in a portion of the vertical passage portions 23a, 23a penetrating the inside of the carburetor body 1. Further, a flat cover member 28 is overlapped on the upper surface of the vaporizer body 1 with a gasket 27 interposed therebetween, and is fixed to the vaporizer body 1 by a set screw 29. These cover the side passage portions 23b and 23b and the port chambers 23c and 23c and are airtight.
[0026]
Next, the two intake passages 2 extend from the upstream end surface of the inlet passage portion 7 of the block piece 16 inserted in the inlet passage portion 7 to the portion between the two venturis 10, 10 of the carburetor body 1. , 2, two sets of main air bleed passages 30, 30 and low speed air bleed passages 32, 32 for the main fuel passages 19, 19, and the low speed fuel passages 23, 23 are parallel to each other in the direction of the central axis of the intake passage 2. Is formed. These are connected to the upper end of the vertical passage portion of the main fuel passage 19 and to the downstream side of the low speed jet 24 of the vertical passage portion 23a of the low speed fuel passage 23, respectively. A main air bleed jet 31 and a low speed air bleed jet 33 are provided at the inlets of the main air bleed passages 30 and the low speed air bleed passage 32.
[0027]
A shut-off valve 41 is provided at the bottom of the fuel container 3 to prevent the diesel phenomenon that occurs when the key switch is turned off to stop the engine.
[0028]
The shut-off valve 41 is electromagnetically driven, and an end face cover body 43 forming a part of a housing of a well-known solenoid type actuator 42 including an electromagnet, a movable iron core, and a spring has a nut 43a and an outer peripheral surface at the center. And a mounting cylinder 44 provided with a male screw 44a. The mounting cylinder 44 has a through hole 45 extending from the tip surface to the inside of the nut 43a, and a plunger 46 that is swingably coupled to the tip of the movable iron core loosens the through hole 45, that is, has a gap around it. It has 47 and penetrates.
[0029]
The mounting cylinder 44 passes through the bottom of the fuel container 3 and is inserted into the constant fuel chamber 6, and the penetrating portion is made liquid-tight by a packing 48 sandwiched between the nut 43 a and the fuel container 3.
[0030]
The shut-off valve 41 has a cylindrical valve body 49. The valve body 49 has an upper end fitted into a recess 14a at the lower end of the block member 14 attached to the lower surface of the carburetor body 1, and has a circumferential surface. The gap is made liquid-tight by the O-ring 50. Further, a female thread 51a is provided at the lower end portion of the valve passage 51 extending in the vertical direction inside the valve body 49, and the male screw 44a of the mounting cylinder 44 is screwed into the female thread 51a, whereby the block member 14 is fitted. The valve body 49 and the actuator 42 are coupled to each other and arranged on the same central axis. It can be seen that the lower end of the valve body 49 is in contact with the bottom of the fuel container 3 and the actuator 42 is suspended.
[0031]
The valve passage 51 has a valve seat 52 at an intermediate portion thereof. The distal end portion of the plunger 46 protrudes in a region below the valve seat 52 of the valve passage 51, and a conical valve body 53 is formed at the distal end.
[0032]
A main jet 34 that regulates the maximum flow rate of the fuel is attached to a portion of the valve body 49 below the valve seat 52 by screwing. The fuel in the constant fuel chamber 6 flows into the valve passage 51 through the main jet 34, and from there, the main fuel passages 19, 19 and the low-speed fuel passages 23, 23 are in the emulsion state by bleed air. The air is sucked into the intake passages 2 and 2 from the nozzle 21, idle port 25 and slow port 26.
[0033]
The electromagnet of the actuator 42 energizes the solenoid when the engine key switch is turned on to generate magnetic force, and retracts the plunger 46 by attracting the movable iron core. Therefore, while the engine is operated, the valve body 53 is separated from the valve seat 52 and the fuel continuously passes through the shutoff valve 41.
[0034]
When the key switch of the engine is turned off, the solenoid is not energized and the movable iron core moves in the direction in which the plunger 46 is advanced by the force of the spring. Accordingly, while the engine is stopped, the valve body 53 is seated on the valve seat 52 and the main fuel passages 19, 19 are closed at their inlet portions.
[0035]
The plunger 46 is swingable. Therefore, even if the valve body 53 and the valve seat 52 are eccentric due to manufacturing errors or assembly errors, the conical valve body 53 is seated on the valve seat 52 on the entire circumferential surface. The constant fuel chamber 6 and the main fuel passages 19 and 19 are completely shut off. For this reason, after the key switch is turned off, the fuel is not supplied and the occurrence of the dieseling phenomenon can be reliably prevented.
[0036]
The clearance 47 that is inevitably provided in the through hole 45 so that the plunger 46 can be swung is kept open in the valve passage 51 of the shutoff valve 41 due to heat generated when the solenoid is energized. The fuel that has flowed into the gap 47 is heated and evaporated to generate bubbles, which enter the main fuel passages 19 and 19 as they are, and as described above, the engine operation may be disturbed.
[0037]
According to the present invention, referring to FIGS. 5A and 5B, the closing member 55 made of a hard flat washer is fixed to the plunger 46 by press fitting. The closing member 55 is attached to the plunger 46 at a position that closes the open end of the gap 47 to the valve passage 51 as shown in FIG. 5A when the solenoid 46 is energized to retract the plunger 46.
[0038]
When the closing member 55 closes the gap 47, the fuel repeatedly flows into the gap 47 and then flows out from the gap 47, and bubbles generated by evaporating at least a part of the injected fuel remain as they are. The phenomenon of being released to 19, 19 is avoided.
[0039]
When the closing member 55 is in contact with the front end surface of the mounting cylinder 44 and completely closes the gap 47 and encloses the fuel, the fuel is not discharged into the main fuel passages 19 and 19 even if bubbles are generated.
[0040]
When the closing member 55 does not completely close the gap 47 and has a narrow gap between the front end surface of the mounting cylinder 44, the bubbles generated by the fuel in the gap 47 are narrow gaps. When passing through the fuel, it is refined and becomes microbubbles that are discharged into the main fuel passages 19 and 19. The microbubbles do not become a resistance to the fuel flow, and do not make the fuel suction into the intake passages 2 and 2 discontinuous. Furthermore, since the closing member 55 does not collide with the mounting cylinder 44 when the plunger 46 is retracted from the advanced position, there is no fear of being damaged.
[0041]
Therefore, when the plunger 46 is retracted, the closing member 55 incompletely closes the gap 47 is one of the preferred modes for carrying out the present invention. In addition, since the object of the present invention can be achieved by making the bubbles generated in the gap 47 fine and discharging, the closing member 55 can also be formed of a porous plate member such as a wire mesh.
[0042]
The gap closing means shown in FIG. 6 is configured such that a closing member 57 made of a hard flat washer is fitted to the plunger 46 so as to be movable in the axial direction, and a snap ring 58 is attached and fixed to the plunger 46.
[0043]
The snap ring 58 is attached to the plunger 46 at a position where it overlaps the closing member 57 and closes the open end of the gap 47 when the plunger 46 is retracted. Even in this configuration, the gap 47 may be completely closed or incompletely closed.
[0044]
The gap closing means shown in FIG. 7 is configured such that an abacus ball-like closing member 59 made of an oil-resistant elastic material such as butyl rubber is fixed to the plunger 46 by press fitting. When the plunger 46 is retracted, the closing member 59 is partly pushed into the open end of the gap 47 so as to come into strong contact with the distal end surface of the mounting cylinder 44 and is attached to the plunger 46 at a position where it is completely closed.
[0045]
Each of the three gap closing means has a structure in which the closing members 55, 57, 59 are made separately from the plunger 46, and the flange 46 is integrally formed on the plunger 46 by forging, for example. It is also possible to use this as a closing member.
[0046]
In the carburetor shown in the drawing, the shut-off valve 41 is placed vertically upward, and the main fuel passages 19, 19 and the low-speed fuel passages 23, 23 branched therefrom extend vertically. ing. Further, these passages reach the main nozzle 21, the idle port 25, and the slow port 26 with a very small number of direction changes. Thus, the present invention is extremely effective for a carburetor having a structure in which air bubbles rise as a large lump and easily flow out to the intake passages 2 and 2.
[0047]
The vaporizer shown in the drawing uses a block member 14 and a block piece 16 which are separate from the vaporizer main body 1, the emulsion tube 20 is inserted into the former, and the main nozzle 21 and the main air bleed jet 31 are inserted into the latter. , A low-speed air bleed jet 33 is provided, and a main jet 34 is provided in a valve main body 49 which is separate from these. Therefore, there is an advantage that these parts can be easily assembled and inspected and can be easily adapted to changes in specifications.
[0048]
【The invention's effect】
As described above, according to the present invention, air bubbles generated by the heat of the solenoid are caused by a very simple means of providing a closing member for closing the clearance around the plunger provided with the valve body of the shut-off valve for measures against diesel. Thus, the dilution of the air-fuel mixture and the discontinuity of the fuel are eliminated, and the engine can be operated stably.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line XX in FIG.
3 is a cross-sectional view taken along line YY in FIG.
4 is a plan view obtained by cutting a part of FIG. 1. FIG.
FIG. 5 is an enlarged partial view of FIG. 2;
FIG. 6 is a partial longitudinal sectional view showing a different embodiment of the present invention.
FIG. 7 is a partial longitudinal sectional view showing still another embodiment of the present invention.
FIG. 8 is a partial longitudinal sectional view showing a conventional example.
[Explanation of symbols]
1 carburetor body, 2 intake passages, 6 constant fuel chambers, 19 main fuel passages, 21 main nozzles, 23 low speed fuel passages, 41 shutoff valves, 42 actuators, 44 mounting cylinders, 45 through holes, 46 plungers, 47 gaps , 49 valve body, 51 valve passage, 52 valve seat, 53 valve body, 55, 57, 59 closing member,

Claims (3)

There is an electromagnetically driven shut-off valve that opens and closes the inlet portion of the main fuel passage that sends fuel in the constant fuel chamber to the main nozzle. The valve body provided at the tip and the valve seat provided at the inlet portion, and the plunger is swingable and loosely penetrates the through hole of the actuator mounting cylinder. A carburetor configured to close the main fuel passage by moving the plunger forward when the key switch is turned off and the valve body seated on the valve seat;
A closing member is provided on the plunger for closing an open end to the inlet portion of the clearance between the through hole and the plunger when the actuator is excited;
A vaporizer characterized by that. The carburetor according to claim 1, wherein the closing member completely closes an open end of the gap at a retracted position of the plunger. The carburetor according to claim 1, wherein the closing member incompletely closes the open end of the gap at the retracted position of the plunger.

Images