CA1098391A - Carburetor - Google Patents
CarburetorInfo
- Publication number
- CA1098391A CA1098391A CA317,105A CA317105A CA1098391A CA 1098391 A CA1098391 A CA 1098391A CA 317105 A CA317105 A CA 317105A CA 1098391 A CA1098391 A CA 1098391A
- Authority
- CA
- Canada
- Prior art keywords
- main
- jet
- carburetor
- holes
- nozzle assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Control Of The Air-Fuel Ratio Of Carburetors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A carburetor provided with a butterfly-shaped throttle valve wherein, in order to make it easy to attach and remove a main nozzle, main jet, pilot jet, pilot air jet and others to and from a carburetor body, the main nozzle assembly including the main nozzle and main jet, the pilot jet, pilot air jet and others are made to be able to be attached from above or outside the carburetor body and a cover plate is provided to hold normal positions of attaching the main nozzle assembly and others.
A carburetor provided with a butterfly-shaped throttle valve wherein, in order to make it easy to attach and remove a main nozzle, main jet, pilot jet, pilot air jet and others to and from a carburetor body, the main nozzle assembly including the main nozzle and main jet, the pilot jet, pilot air jet and others are made to be able to be attached from above or outside the carburetor body and a cover plate is provided to hold normal positions of attaching the main nozzle assembly and others.
Description
~83~1 The present invention relates to carburetors for internal combustion engines and more particularly to improvements in a carburetor of a type provided with a butterfly-shaped throttle valve.
The present invention will be illustrated by way the accompanying drawings in which:
Fig. 1 is a vertical sectional view showing a basic structure of a conventional carburetor provided with a butterfly-shaped throttle valve;
Fig. 2 is a vertical sectional view showing a carburetor embodying the present invention;
Fig. 3 is a right side view of Fig. 2 as partly sectioned;
Fig. 4 is an elevational view of a nozzle tube;
Fig. 5 is a top view of a main nozzle assembly; and, Fig. 6 is a vertical sectional view showing another carburetor embodying the present invention.
Fig. 1 shows a basic structure of a carburetor of a type provided with a known butterfly-shaped throttle valve used mostly for internal combustion engines for general purposes. In the drawing reference numeral 1 indicates a carburetor body, 2 indicates a venturi portion, 3 indicates a butterfly-shaped throttle valve, 4 indicates a main nozzle, 5 indicates a main jet, 6 indicates a main air jet, 7 indicates a pilot jet, 8 indicates a pilot air jet, 9 indicates a low speed fuel passage, 10 indicates an idling screw, 11 indicates a float, 12 indicates a cover case for defining a float chamber, 13 indicates a screw for attaching the cover case 12 to the carburetor body 1 and lA indicates a boss portion hanging into the float chamber. As this kind of carburetor is arranged as described above, for example, in case the main jet 5 is to be removed from the boss portion lA so as to be replaced, first the cover case 12 will have to be removed from the carburetor body 1.
As a result, when the carburetor is attached to an engine, a very difficult work will be forced. Further, as the boss portion lA
occupies a comparatively large volume part within the float chamber, 10"83~1 !
effective volume of the float chamber will reduce and therefore the float chamber will have to be comparatively large as a whole.
As the float 11 must also be made to be in such form as will not contact the boss portion lA, there has been a disadvantage that the structure is limited. The same problem as in the case of the main jet S will occur also in the case of replacing the pilot jet 7.
The present invention eliminates the above described defects in a carburetor of the above mentioned type.
According to the present invention, this is attained by suspending a main nozzle assembly including a main jet and main air jet into a float chamber across a venturi portion from the upper portion of a carburetor body and setting a pilot jet in the upper portion of the carburetor body.
The present invention also provides a carburetor wherein such parts as a main nozzle~ main jet and pilot jet are so arranged as to be able to be easily attached to and removed from a carburetor body.
The present invention further provides a small carburetor of a simplified structure.
The present invention again provides a carburetor which can be manufactured at a low cost.
According to the present invention there is provided a car-buretor provided with a butterfly-shaped throttle valve, comprising a carburetor body including therein at least a suction bore having a horizontally extending venturi portion and through holes extending vertically across said suction bore and opening in said venturi portion; a float chamber defined below said body; a main nozzle assembly capable of being inserted into said through holes from above said body and including therein a main air jet, at least a nozzle opening in said suction bore and a main jet capable of being positioned in said float chamber; and a cover plate secured removably to the top portion of said body to cover the upper portion of said main nozzle assembly.
" ~.
~Qq83~1 Referring once more to the accompanying drawings, the same corresponding reference numerals are attached to the same parts and portions as in Fig. 1.
First, with reference to Fig. 2, reference numeral 14 indicates a main nozzle assembly including a tubular jet holder 15 air-tightly fitted within a through hole la extending vertically to a boss portion lA and a nozzle tube 16 inserted air-tightly through a hole lb made in the upper portion of a carburetor body 1 coaxially with the through hole la and screwed at the lower end to the upper end of the jet holder 15 within the through hole la. The air-tightness between the through hole la and jet holder 15 is secured by an O-ring 17 interposed between a step portion formed within the through hole la and a flange portion formed in the jet holder 15. The air-tightness between the hole lb and nozzle tube 16 secured by an O-ring 18 interposed between a step c ~
~,Q'~8391 portion formed in the hole lb and a flange portion formed in the nozzle tube 16. A main jet 19 is screwed to the lower end of the jet holder 15. The inlet of the main jet 19 communicates with the interior of a float chamber lB through S a hole lA' made in the side wall of the boss portion lA. A
bleeding pipe 20 is inserted into the nozzle tube 16, extends in the lower end portion to the upper end portion of the jet holder 15 and is connected at the upper end to a main air jet 21 screwed in from the upper open end of the nozzle tube 16. A vertically extended slot-shaped nozzle 16a (Fig. 4) is formed in the middle portion exposed within a suction bore lC of the nozzle tube 16 and is directed toward the downstream side of the suction bore lC, that is, toward the throttle valve 3. In this case, a plurality of nozzles 16a may be provided. The head portion of the nozzle tube 16 is positioned within the large diameter portion of the hole lb and an annular air chamher lD communicating with the suction bore lC is formed b~tween the outer peripheral surface of this head portion and the inner wall surface of the large diameter portion of the hole lb. A diametrally extending groove 16b (Fig. 5) is formed on the top surface of the nozzle tube 16, ~he inlet o~ the main air jet 21 communicates with the a~r chamber lD through the groove 16b.
Further, a flat cut portion 16c (Fig. 5) is provided in the flange portion of the nozzle tube 16. Onl~ when this cut portion 16c meets a corresponding flat cllt portion lb' (Fig. 5) formed on the inner wall of the hole lb, the main nozzle assembly 14 will be abl~ to occupy a correct position 10~8391 ~in which the nozzle 16a is directed toward the throttle valve 3) shown in Fig. 2. The nozzle 16a is directed toward the throttle valve 3, that is, toward the intake manifold side in order to make the outflow of the fuel easy and to prevent the fuel from jetting out to make a too rich ~ L6~
mixture in the case of spitting back. However, it is nccdlco-.,, to say that the direction of the nozzle 16a can be properly changed depending on the kind of the engine. The main nozzle assembly 14 is pressed down on the top surface by a cover plate 23 secured to the carburetor body 1 through a gasket 22 so that the air-tightness between the jet holder 15 and through hole la and between the nozzle tube 16 and hole lb may be secured.
A bottomed cylindrical jet block 24 fitted air-tightly within a hole lc is provided in the upper portion of the carburetor body 1 adjacent to the air chamber lD. A hole 24a communicating with a passage ld the flow volume of the fuel passing through which can be adjusted by an idling screw 10 and another hole 24b are made in the peripheral wall of the jet block 24. Holes 24c communicating with the suction bore lC are made in the bottom wall of the jet block 24.
The upper opening of this jet block 24 is closed by the cover plate 23 through the gasket 22. Particularly with reference to Fig. 3, a fuel passage le opened at one end in the float chamber lB and connected at the other end to the hole 24b of the jet block 24 is provided within the carburetor body 1. In the course of this fuel passage le, there are provided a pilot jet 25 screwed from above into the carburetor 10~83~1 body 1 and a pilot air jet 26 also screwed from above into the carburetor body 1. The pilot air jet 26 communicates with a chamber lE closed by the cover plate 23 through the gasket 22 and communicating with the air chamber lD. ~eference numeral 27 indicates a bolt screwed to the lower end of the boss portion lA to liquid-tightly attach the cover case 12 to the carburetor body 1.
As evident from the above description, the main nozzle assembly 14 forms a main fuel system and the fuel passage le, pilot jet 25, pilot air jet 26 and jet block 24 form a low speed fuel system.
Another carburetor embodying the present invention is shown Fig. 6. In this embodiment, the main nozzle assembly 14 is further simplified. That is to say, the nozzle tube and jet holder are formed integrally with each other and the main air jet 21 and main jet 19 are screwed respectively in the upper portion and lower portion. Further, the main nozzle assembly 14 is attached to the carburetor body 1 by screwing as illustrated and no boss portion lA is present It is needless to say that, in this case, the bleeding pipe may be inserted into the main nozzle assembly 14 in the same manner as ir. the embodiment shown in Fig. 2. Further, in this embodi-ment, the pilot jet 25 is below th~ pilot air jet 26 and these are arranged concentrically with each other.
As the carburetor according to the present invention is formed as described above, when the component parts of the main nozzle assembly 14 must be replaced, the object of replacing them will be able to be attained simply by only lOq8391 removing the cover plate ~3. In the same manner, also in the case of attachin~ the main nozzle assembly 14 to the carburetor body l, the necessary work will be able to be completed by only inserting the main nozzle assembly 14 pre-assembled in advance into the holes la and lb and securing the cover plate 23 to the carburetor body l. Thus, the above mentioned work can be made very simple while the carburetor body is attached to the engine. This advantage ~ill be developed also in the case of replacing the pilot jet 25 and pilot air jet 26.
As the boss portion lA projecting into the float chamber lB can be made to be of a shape smaller and simpler than of the conventional one, the reduction of the effective volume of the float chamber lB will be able to be reduced and the freedom of the selection of the structure and attaching position of the float ll will become larger. As a result, the size of the entire float chamber will be able to be made smaller and it will be possible to make the size of the entire carburetor smaller. Further, if the cover case 12 is to be attached to the lower end of the boss port1on lA with the bolt 27 from outside as in the embodiment shown in Fig. 2, the cover case will be able to be made by pressing a plate without being cast such as being diecast and therefore the cost of the manufacture of the entire carburetor will be able to be reduced.
A proper amount of a mixture obtained from a fuel sucked
The present invention will be illustrated by way the accompanying drawings in which:
Fig. 1 is a vertical sectional view showing a basic structure of a conventional carburetor provided with a butterfly-shaped throttle valve;
Fig. 2 is a vertical sectional view showing a carburetor embodying the present invention;
Fig. 3 is a right side view of Fig. 2 as partly sectioned;
Fig. 4 is an elevational view of a nozzle tube;
Fig. 5 is a top view of a main nozzle assembly; and, Fig. 6 is a vertical sectional view showing another carburetor embodying the present invention.
Fig. 1 shows a basic structure of a carburetor of a type provided with a known butterfly-shaped throttle valve used mostly for internal combustion engines for general purposes. In the drawing reference numeral 1 indicates a carburetor body, 2 indicates a venturi portion, 3 indicates a butterfly-shaped throttle valve, 4 indicates a main nozzle, 5 indicates a main jet, 6 indicates a main air jet, 7 indicates a pilot jet, 8 indicates a pilot air jet, 9 indicates a low speed fuel passage, 10 indicates an idling screw, 11 indicates a float, 12 indicates a cover case for defining a float chamber, 13 indicates a screw for attaching the cover case 12 to the carburetor body 1 and lA indicates a boss portion hanging into the float chamber. As this kind of carburetor is arranged as described above, for example, in case the main jet 5 is to be removed from the boss portion lA so as to be replaced, first the cover case 12 will have to be removed from the carburetor body 1.
As a result, when the carburetor is attached to an engine, a very difficult work will be forced. Further, as the boss portion lA
occupies a comparatively large volume part within the float chamber, 10"83~1 !
effective volume of the float chamber will reduce and therefore the float chamber will have to be comparatively large as a whole.
As the float 11 must also be made to be in such form as will not contact the boss portion lA, there has been a disadvantage that the structure is limited. The same problem as in the case of the main jet S will occur also in the case of replacing the pilot jet 7.
The present invention eliminates the above described defects in a carburetor of the above mentioned type.
According to the present invention, this is attained by suspending a main nozzle assembly including a main jet and main air jet into a float chamber across a venturi portion from the upper portion of a carburetor body and setting a pilot jet in the upper portion of the carburetor body.
The present invention also provides a carburetor wherein such parts as a main nozzle~ main jet and pilot jet are so arranged as to be able to be easily attached to and removed from a carburetor body.
The present invention further provides a small carburetor of a simplified structure.
The present invention again provides a carburetor which can be manufactured at a low cost.
According to the present invention there is provided a car-buretor provided with a butterfly-shaped throttle valve, comprising a carburetor body including therein at least a suction bore having a horizontally extending venturi portion and through holes extending vertically across said suction bore and opening in said venturi portion; a float chamber defined below said body; a main nozzle assembly capable of being inserted into said through holes from above said body and including therein a main air jet, at least a nozzle opening in said suction bore and a main jet capable of being positioned in said float chamber; and a cover plate secured removably to the top portion of said body to cover the upper portion of said main nozzle assembly.
" ~.
~Qq83~1 Referring once more to the accompanying drawings, the same corresponding reference numerals are attached to the same parts and portions as in Fig. 1.
First, with reference to Fig. 2, reference numeral 14 indicates a main nozzle assembly including a tubular jet holder 15 air-tightly fitted within a through hole la extending vertically to a boss portion lA and a nozzle tube 16 inserted air-tightly through a hole lb made in the upper portion of a carburetor body 1 coaxially with the through hole la and screwed at the lower end to the upper end of the jet holder 15 within the through hole la. The air-tightness between the through hole la and jet holder 15 is secured by an O-ring 17 interposed between a step portion formed within the through hole la and a flange portion formed in the jet holder 15. The air-tightness between the hole lb and nozzle tube 16 secured by an O-ring 18 interposed between a step c ~
~,Q'~8391 portion formed in the hole lb and a flange portion formed in the nozzle tube 16. A main jet 19 is screwed to the lower end of the jet holder 15. The inlet of the main jet 19 communicates with the interior of a float chamber lB through S a hole lA' made in the side wall of the boss portion lA. A
bleeding pipe 20 is inserted into the nozzle tube 16, extends in the lower end portion to the upper end portion of the jet holder 15 and is connected at the upper end to a main air jet 21 screwed in from the upper open end of the nozzle tube 16. A vertically extended slot-shaped nozzle 16a (Fig. 4) is formed in the middle portion exposed within a suction bore lC of the nozzle tube 16 and is directed toward the downstream side of the suction bore lC, that is, toward the throttle valve 3. In this case, a plurality of nozzles 16a may be provided. The head portion of the nozzle tube 16 is positioned within the large diameter portion of the hole lb and an annular air chamher lD communicating with the suction bore lC is formed b~tween the outer peripheral surface of this head portion and the inner wall surface of the large diameter portion of the hole lb. A diametrally extending groove 16b (Fig. 5) is formed on the top surface of the nozzle tube 16, ~he inlet o~ the main air jet 21 communicates with the a~r chamber lD through the groove 16b.
Further, a flat cut portion 16c (Fig. 5) is provided in the flange portion of the nozzle tube 16. Onl~ when this cut portion 16c meets a corresponding flat cllt portion lb' (Fig. 5) formed on the inner wall of the hole lb, the main nozzle assembly 14 will be abl~ to occupy a correct position 10~8391 ~in which the nozzle 16a is directed toward the throttle valve 3) shown in Fig. 2. The nozzle 16a is directed toward the throttle valve 3, that is, toward the intake manifold side in order to make the outflow of the fuel easy and to prevent the fuel from jetting out to make a too rich ~ L6~
mixture in the case of spitting back. However, it is nccdlco-.,, to say that the direction of the nozzle 16a can be properly changed depending on the kind of the engine. The main nozzle assembly 14 is pressed down on the top surface by a cover plate 23 secured to the carburetor body 1 through a gasket 22 so that the air-tightness between the jet holder 15 and through hole la and between the nozzle tube 16 and hole lb may be secured.
A bottomed cylindrical jet block 24 fitted air-tightly within a hole lc is provided in the upper portion of the carburetor body 1 adjacent to the air chamber lD. A hole 24a communicating with a passage ld the flow volume of the fuel passing through which can be adjusted by an idling screw 10 and another hole 24b are made in the peripheral wall of the jet block 24. Holes 24c communicating with the suction bore lC are made in the bottom wall of the jet block 24.
The upper opening of this jet block 24 is closed by the cover plate 23 through the gasket 22. Particularly with reference to Fig. 3, a fuel passage le opened at one end in the float chamber lB and connected at the other end to the hole 24b of the jet block 24 is provided within the carburetor body 1. In the course of this fuel passage le, there are provided a pilot jet 25 screwed from above into the carburetor 10~83~1 body 1 and a pilot air jet 26 also screwed from above into the carburetor body 1. The pilot air jet 26 communicates with a chamber lE closed by the cover plate 23 through the gasket 22 and communicating with the air chamber lD. ~eference numeral 27 indicates a bolt screwed to the lower end of the boss portion lA to liquid-tightly attach the cover case 12 to the carburetor body 1.
As evident from the above description, the main nozzle assembly 14 forms a main fuel system and the fuel passage le, pilot jet 25, pilot air jet 26 and jet block 24 form a low speed fuel system.
Another carburetor embodying the present invention is shown Fig. 6. In this embodiment, the main nozzle assembly 14 is further simplified. That is to say, the nozzle tube and jet holder are formed integrally with each other and the main air jet 21 and main jet 19 are screwed respectively in the upper portion and lower portion. Further, the main nozzle assembly 14 is attached to the carburetor body 1 by screwing as illustrated and no boss portion lA is present It is needless to say that, in this case, the bleeding pipe may be inserted into the main nozzle assembly 14 in the same manner as ir. the embodiment shown in Fig. 2. Further, in this embodi-ment, the pilot jet 25 is below th~ pilot air jet 26 and these are arranged concentrically with each other.
As the carburetor according to the present invention is formed as described above, when the component parts of the main nozzle assembly 14 must be replaced, the object of replacing them will be able to be attained simply by only lOq8391 removing the cover plate ~3. In the same manner, also in the case of attachin~ the main nozzle assembly 14 to the carburetor body l, the necessary work will be able to be completed by only inserting the main nozzle assembly 14 pre-assembled in advance into the holes la and lb and securing the cover plate 23 to the carburetor body l. Thus, the above mentioned work can be made very simple while the carburetor body is attached to the engine. This advantage ~ill be developed also in the case of replacing the pilot jet 25 and pilot air jet 26.
As the boss portion lA projecting into the float chamber lB can be made to be of a shape smaller and simpler than of the conventional one, the reduction of the effective volume of the float chamber lB will be able to be reduced and the freedom of the selection of the structure and attaching position of the float ll will become larger. As a result, the size of the entire float chamber will be able to be made smaller and it will be possible to make the size of the entire carburetor smaller. Further, if the cover case 12 is to be attached to the lower end of the boss port1on lA with the bolt 27 from outside as in the embodiment shown in Fig. 2, the cover case will be able to be made by pressing a plate without being cast such as being diecast and therefore the cost of the manufacture of the entire carburetor will be able to be reduced.
A proper amount of a mixture obtained from a fuel sucked
2~ in through the main jet l9 and air sucked in through the main air jet will be jetted out through the nozzle 16a depending on the opened degree of the throttle valve 3.
However, the operation of the carburetor according to ~l~n8391 the present invention is the same as of the conventional carburetor this kind and therefore shall not be explained in detail.
By the way, it is needless to say that, in Fig. 2, the main nozzle assembly 16 can be secured to the carburetor body 1 by being screwed into the through holes la and/or lb in the same manner as in the embodiment in Fig. 6. In such case, it will be preferable to use at least a gasket instead of the O-ring 18.
However, the operation of the carburetor according to ~l~n8391 the present invention is the same as of the conventional carburetor this kind and therefore shall not be explained in detail.
By the way, it is needless to say that, in Fig. 2, the main nozzle assembly 16 can be secured to the carburetor body 1 by being screwed into the through holes la and/or lb in the same manner as in the embodiment in Fig. 6. In such case, it will be preferable to use at least a gasket instead of the O-ring 18.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A carburetor provided with a butterfly-shaped throttle valve, comprising a carburetor body including therein at least a suction bore having a horizontally extending verturi portion and through holes extending vertically across said suction bore and opening in said venturi portion; a float chamber defined below said body; a main nozzle assembly capable of being inserted into said through holes from above said body and including therein a main air jet, at least a nozzle opening in said suction bore and a main jet capable of being positioned in said float chamber; and a cover plate secured removably to the top portion of said body to cover the upper portion of said main nozzle assembly.
2. A carburetor according to claim 1 wherein said main nozzle assembly includes a nozzle tube capable of being sealably fitted within said through holes and having respectively said main jet at the lower end, at least one said nozzle in the inter-mediate portion, said main air jet in the upper end portion and a bleed pipe connected to said main air jet within it.
3. A carburetor according to claim 2 wherein said nozzle tube has a means capable of determining a correct position of inserting said main nozzle assembly into said through holes in cooperation with said body and is held in a predetermined position within said through holes by said cover plate.
4. A carburetor according to claim 1 wherein said nozzle is directed toward the downstream side of said suction bore.
5. A carburetor according to claim 1 wherein said carburetor further comprises a pilot jet capable of being screwed from outside said body and a pilot air jet covered by said cover plate and capable of being screwed vertically downward from above said body.
6. A carburetor according to claim 1 wherein said body further includes a boss portion extending into said float chamber and including said through holes therein and a cover case for defining said float chamber is detachably secured to the lower end of said boss portion.
7. A carburetor according to claim 1 wherein said main nozzle assembly is held in a predetermined position within said through holes by screw means.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA317,105A CA1098391A (en) | 1978-11-29 | 1978-11-29 | Carburetor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA317,105A CA1098391A (en) | 1978-11-29 | 1978-11-29 | Carburetor |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1098391A true CA1098391A (en) | 1981-03-31 |
Family
ID=4113038
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA317,105A Expired CA1098391A (en) | 1978-11-29 | 1978-11-29 | Carburetor |
Country Status (1)
Country | Link |
---|---|
CA (1) | CA1098391A (en) |
-
1978
- 1978-11-29 CA CA317,105A patent/CA1098391A/en not_active Expired
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Legal Events
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