CA1166099A - Compound carburetor - Google Patents
Compound carburetorInfo
- Publication number
- CA1166099A CA1166099A CA000390867A CA390867A CA1166099A CA 1166099 A CA1166099 A CA 1166099A CA 000390867 A CA000390867 A CA 000390867A CA 390867 A CA390867 A CA 390867A CA 1166099 A CA1166099 A CA 1166099A
- Authority
- CA
- Canada
- Prior art keywords
- running
- slow
- cylinders
- primary
- secondary slow
- 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
Abstract
ABSTRACT OF THE DISCLOSURE
A compound carburetor wherein, in order that, in the course of the transit from the primary side to the secondary side, an air-fuel mixture fed to each cylinder may maintain a uniform air-fuel ratio without causing an air lock and the transit may be made smoothly and definitely, an independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes in the course a pipe connected between a carburetor part and manifold part.
A compound carburetor wherein, in order that, in the course of the transit from the primary side to the secondary side, an air-fuel mixture fed to each cylinder may maintain a uniform air-fuel ratio without causing an air lock and the transit may be made smoothly and definitely, an independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes in the course a pipe connected between a carburetor part and manifold part.
Description
~ ~6609~
This invention relates to a compound carburetor for use in an internal combustion engine having a plurali-ty of cylinders.
In a compound carburetor for use in an engine having a plurality of cylinders, a primary air-fuel mixture passes through one throttle valve and is then distributed to respective cylinders, a secondary air-fuel mixture is fed to the respective cylinders through secondary throttle valves arranged for the respective cylinders and a secondary slow-running fuel system for controlling the air-fuel ratio at the beginning of opæ~ing of the secondary throttle valves is prov ided to smooth the tr-ansit from the primary side to the secondary side. Howeverl in this type of conventional cc~ound carburetor, generally, there have been the defect that, as one secondary slow-running fuel system is distributed to the secondary throttle valves of the respective cylinders, due to the fluctuation of the opening of the secondary throttle valve for each cylinder, the fluctuation of the opening area of the secondary bypass hole, the difference in the length and bend of the secondary slow-running mixture path and the air locking phenomenon during the secondary slow-running mixture path likely to occur at a high temperature which are all difficult to technically solve, the air-fuel ratio of the mixture for each cylinder will fluctuate during the transit from the primary side to the secondary side and the transit will no longer be smooth.
This invention relates to a compound carburetor for use in an internal combustion engine having a plurali-ty of cylinders.
In a compound carburetor for use in an engine having a plurality of cylinders, a primary air-fuel mixture passes through one throttle valve and is then distributed to respective cylinders, a secondary air-fuel mixture is fed to the respective cylinders through secondary throttle valves arranged for the respective cylinders and a secondary slow-running fuel system for controlling the air-fuel ratio at the beginning of opæ~ing of the secondary throttle valves is prov ided to smooth the tr-ansit from the primary side to the secondary side. Howeverl in this type of conventional cc~ound carburetor, generally, there have been the defect that, as one secondary slow-running fuel system is distributed to the secondary throttle valves of the respective cylinders, due to the fluctuation of the opening of the secondary throttle valve for each cylinder, the fluctuation of the opening area of the secondary bypass hole, the difference in the length and bend of the secondary slow-running mixture path and the air locking phenomenon during the secondary slow-running mixture path likely to occur at a high temperature which are all difficult to technically solve, the air-fuel ratio of the mixture for each cylinder will fluctuate during the transit from the primary side to the secondary side and the transit will no longer be smooth.
-2-~ ~66~)9~
Further, generally, the carburetor body is divided into a carburetor portion, a manifold portion and a throttle body portion and is formed by a combination thereof. However~ the secondary slow-running fuel system or particularly the secon-dary slow-running mixture path is formed within these respec-tiveportions, is therefore comparatively long in the total length and can not help having many bends. Not only this will be likely to cause an air locking phenomenon when the engine temperature rises as described above but also it will increase the flow resistance to cause the aelay of the transit from the primary side to the secondary side and the unstable jet of the mixture. Therefore, in order to shorten the total length of the secondary slow-running mixture path and to decrease the bends, attempts have been made to arrange the carburetor portion and throttle body portion in the same plane. However, there have been defects that this arrangement will not only increase the useless thickness of the component parts but also require a large space and cause a leakage due to different strains of the respective portion by heat.
Therefore, the present invention provides a compound carburetor for internal combustion engines wherein the transit from the primary side to the secondary side is smoothly made and the air-fuel. ratio of a mixture fed to each cylinder does not fluctuate.
According to the present invention, there is provided an independent secondary slow-running fuel system 1 16609~
for one cylinder or each of two cylinders.
According to the present invention therefore there is provided a compound carburetor comprisiny a primary bore provided therein with a primary throttle valve and branched in the downstream part of said primary throttle valve to be respectively connected to a plurality of cylinders of an engine a secondary bore arranged adjacently to said primary bore and branched in the downstream part to be respectively connected to said plurality of cylinders through secondary throttle valves arranged respectively for said plurality of cylinders, and a plurality of secondary slow-running fuel systems set respectively independently for said plurality of cylinders, opened respectively in the vicinity of said respective secondary throttle valves, and cooperating respectively with said respective secondary throttle valves.
According to a preferred embodiment of the present invention, the mixture path of the secondary slow-running fuel system includes a pipe airtightly fitted between one part and the other part of the carburetor body. Thereby, the length of the mixture path of the secondary slow-running fuel system can be made as short as possible and the above described problems can be solved. The pipe is fitted with an O-ring made of an elastic sealing material or has a rib formed at each end and is rnade preferably of such adiabatic material as a phenol resin.
The present invention will be further illustrated by way of the accompanying drawings in which:
Fig. 1 is a partly sectioned plan view of an em-bodiment of a compound carburetor according to the present inYention;
Fig. 2 is a side view of the compound carburetor shown in Fig. l;
Fig. 3 is a sectional view showing an embodiment of a pipe ~orming a part of a mixture path of a secondary slow-running fueI system; and Fig. 4 is a sectional view showing another embodi-ment of a pipe forming a part of a mixture path of a second-ary slow-n1nning fuel system.
With reference to Figs. 1 and 2, the reference numeral 1 indicates a carburetor body consisting of a car-buretor portion la, manifold portion lb and throttle body poxtion lc, 2 indicates a primary bore and 3 indicates a primary throttle valve provided on the downstream side of a venturi portion (not illustrated).
- 4a -, .. . .
....
6 0 9 ~
The primary bore 2 is branched on the ~own~
stream side of the primary throttle vaive 3 and is con-nected to each cylinder. rrhe reference nurneral 4 indicates a secondary bore whi;ch is branched on the downstream side of the venturi portion (not illustrated) and is connected to each cylinder. The reference numeral 5 inaicates a secondary throttle shaft passing through each branched path 4a of the secondary bore 4 in the direction inter-secting at right angles with the center line of the branch-ed path 4a and 6 indicates a secondary throttle valve secured to the secondary throttle shaft 5 within each branch-ed path 4a. The reference numeral 7 indicates a secondary - bypass hole provided in the inner wall of each branched path 4a and 8 indicates a secondary slow-running jet connected to each secondary bypass hole 7 through each secondary slow-running mixture path 9. A pipe 10 fitted at one end to the carburetor portion la and at the other end to the manifold portion lb is set in each secondary slow-running mixture path 9, that is, between the part positioned in the carbur-etor portion la of the path 9 and the part positioned in the manifold portion lb so as to make the length of the mixture path 9 as short as possible. In connecting so many holes, the pitch and size of the holes will likely fluctuate and problems will likely arise in the concentricity and sealab ility. However, in the case of this embodiment, as shown in Fig. 3, O-rings 11 made of an elastic sealing material are fitted on the outer peripheral portions at both ends of the pipe 10. Also as shown in Fig. 4, the pipe 10 itself may be o ~ ~
molded of an elastic sealing material to have ribs lOa integrally Eormed on the outer peripheral pdrtions a~ both ends. Further, if such adiabatic material, such as a phenol resin, is used for the material of the pipe 10, the pipe will be thermally excellent. The reference numeral 12 in-dicates a secondary slow-running air jet connected to each secondary slow-running jet 8 and 13 indicates a secondary slow-running fuel path connecting each secondary slow-runn-ing air jet 12 with a ~loat chamber 14. The part from the secondary bypass hole 7 to the secondary slow-running fuel path 13 forms a secondary slow-running fuel system and each secondary slow-running jet 8 can have its size freely selected.
The operation of the above described compound car-buretor is explained as follows.
~ uring the operation of the engine, if a pedal (not illustrated) is pressed down for the acceleration, first the primary throttle valve will open and then the 2~ secondary throttle valve will open to gradually feed a large amount of a thick air-fuel mixture to each cylinder~ In this case, during the transit from the primary side to the secondary side, at the initiation of the opening of the secondary throttle valve ~, each secondary slow-running fuel system will act independently on each cylinder. There-fore, even if the opening of the secondary throttle valve 6 for each cylinder and the opening area of the secondary by-pass hole 7 fluctuate and the length and bend of the seco-ndary slow-running mixture path are different, by individ-ually adjusting the size of each secondary slow-running jet 8, the fluctuation of the air-fuel ratio for each cylinder during the above mentioned transit will be able to be reduced. Further, as the secondary slow-running fuel systems for the respective cylinders are independent so as not to interfere with each other, the size of the second-ary slow-running jet 8 for each cylinder can be freely g ~
selected and, as a xesult, the air fuel ratio for each cylinder during the above mentioned transit can be made opti~lum by taking the thermal factors and vibration cond-itions into consiaera*ion. Fr~m the above, according-to the compound carburetor of the present invention, the transit from the primary side to the secondary side can be made very smooth Furthex, the length of the sPcondary slow-running mixture path 9 is so short that substantially no air locking phenomenon will be generated byl:the temperature rise or the like. Therefore, the total volume of the secondary slow-running fuel systems can be made so small and the number of bends of the secondary slow-running mixture path 9 can be made so few that the passage resistance will reduce, the transit delay and unstable jetting of the mixture will be eliminated and, a~ a result, the response characteristic will improve. Further, as the secondary slow-running mixture path g is connected through the pipe 10 in the course, the freedom of the equipment will increase.
In the above mentioned embodiment, the secondary slow-running fuel systems are provided independently for the respective cylinders. However, even if one secondary slow-running fuel system is provided independently for two cylinders so as to serve the two cylinders, the same effect will be able to be obtained. This formation is very advantageous as to the cost.
.
Further, generally, the carburetor body is divided into a carburetor portion, a manifold portion and a throttle body portion and is formed by a combination thereof. However~ the secondary slow-running fuel system or particularly the secon-dary slow-running mixture path is formed within these respec-tiveportions, is therefore comparatively long in the total length and can not help having many bends. Not only this will be likely to cause an air locking phenomenon when the engine temperature rises as described above but also it will increase the flow resistance to cause the aelay of the transit from the primary side to the secondary side and the unstable jet of the mixture. Therefore, in order to shorten the total length of the secondary slow-running mixture path and to decrease the bends, attempts have been made to arrange the carburetor portion and throttle body portion in the same plane. However, there have been defects that this arrangement will not only increase the useless thickness of the component parts but also require a large space and cause a leakage due to different strains of the respective portion by heat.
Therefore, the present invention provides a compound carburetor for internal combustion engines wherein the transit from the primary side to the secondary side is smoothly made and the air-fuel. ratio of a mixture fed to each cylinder does not fluctuate.
According to the present invention, there is provided an independent secondary slow-running fuel system 1 16609~
for one cylinder or each of two cylinders.
According to the present invention therefore there is provided a compound carburetor comprisiny a primary bore provided therein with a primary throttle valve and branched in the downstream part of said primary throttle valve to be respectively connected to a plurality of cylinders of an engine a secondary bore arranged adjacently to said primary bore and branched in the downstream part to be respectively connected to said plurality of cylinders through secondary throttle valves arranged respectively for said plurality of cylinders, and a plurality of secondary slow-running fuel systems set respectively independently for said plurality of cylinders, opened respectively in the vicinity of said respective secondary throttle valves, and cooperating respectively with said respective secondary throttle valves.
According to a preferred embodiment of the present invention, the mixture path of the secondary slow-running fuel system includes a pipe airtightly fitted between one part and the other part of the carburetor body. Thereby, the length of the mixture path of the secondary slow-running fuel system can be made as short as possible and the above described problems can be solved. The pipe is fitted with an O-ring made of an elastic sealing material or has a rib formed at each end and is rnade preferably of such adiabatic material as a phenol resin.
The present invention will be further illustrated by way of the accompanying drawings in which:
Fig. 1 is a partly sectioned plan view of an em-bodiment of a compound carburetor according to the present inYention;
Fig. 2 is a side view of the compound carburetor shown in Fig. l;
Fig. 3 is a sectional view showing an embodiment of a pipe ~orming a part of a mixture path of a secondary slow-running fueI system; and Fig. 4 is a sectional view showing another embodi-ment of a pipe forming a part of a mixture path of a second-ary slow-n1nning fuel system.
With reference to Figs. 1 and 2, the reference numeral 1 indicates a carburetor body consisting of a car-buretor portion la, manifold portion lb and throttle body poxtion lc, 2 indicates a primary bore and 3 indicates a primary throttle valve provided on the downstream side of a venturi portion (not illustrated).
- 4a -, .. . .
....
6 0 9 ~
The primary bore 2 is branched on the ~own~
stream side of the primary throttle vaive 3 and is con-nected to each cylinder. rrhe reference nurneral 4 indicates a secondary bore whi;ch is branched on the downstream side of the venturi portion (not illustrated) and is connected to each cylinder. The reference numeral 5 inaicates a secondary throttle shaft passing through each branched path 4a of the secondary bore 4 in the direction inter-secting at right angles with the center line of the branch-ed path 4a and 6 indicates a secondary throttle valve secured to the secondary throttle shaft 5 within each branch-ed path 4a. The reference numeral 7 indicates a secondary - bypass hole provided in the inner wall of each branched path 4a and 8 indicates a secondary slow-running jet connected to each secondary bypass hole 7 through each secondary slow-running mixture path 9. A pipe 10 fitted at one end to the carburetor portion la and at the other end to the manifold portion lb is set in each secondary slow-running mixture path 9, that is, between the part positioned in the carbur-etor portion la of the path 9 and the part positioned in the manifold portion lb so as to make the length of the mixture path 9 as short as possible. In connecting so many holes, the pitch and size of the holes will likely fluctuate and problems will likely arise in the concentricity and sealab ility. However, in the case of this embodiment, as shown in Fig. 3, O-rings 11 made of an elastic sealing material are fitted on the outer peripheral portions at both ends of the pipe 10. Also as shown in Fig. 4, the pipe 10 itself may be o ~ ~
molded of an elastic sealing material to have ribs lOa integrally Eormed on the outer peripheral pdrtions a~ both ends. Further, if such adiabatic material, such as a phenol resin, is used for the material of the pipe 10, the pipe will be thermally excellent. The reference numeral 12 in-dicates a secondary slow-running air jet connected to each secondary slow-running jet 8 and 13 indicates a secondary slow-running fuel path connecting each secondary slow-runn-ing air jet 12 with a ~loat chamber 14. The part from the secondary bypass hole 7 to the secondary slow-running fuel path 13 forms a secondary slow-running fuel system and each secondary slow-running jet 8 can have its size freely selected.
The operation of the above described compound car-buretor is explained as follows.
~ uring the operation of the engine, if a pedal (not illustrated) is pressed down for the acceleration, first the primary throttle valve will open and then the 2~ secondary throttle valve will open to gradually feed a large amount of a thick air-fuel mixture to each cylinder~ In this case, during the transit from the primary side to the secondary side, at the initiation of the opening of the secondary throttle valve ~, each secondary slow-running fuel system will act independently on each cylinder. There-fore, even if the opening of the secondary throttle valve 6 for each cylinder and the opening area of the secondary by-pass hole 7 fluctuate and the length and bend of the seco-ndary slow-running mixture path are different, by individ-ually adjusting the size of each secondary slow-running jet 8, the fluctuation of the air-fuel ratio for each cylinder during the above mentioned transit will be able to be reduced. Further, as the secondary slow-running fuel systems for the respective cylinders are independent so as not to interfere with each other, the size of the second-ary slow-running jet 8 for each cylinder can be freely g ~
selected and, as a xesult, the air fuel ratio for each cylinder during the above mentioned transit can be made opti~lum by taking the thermal factors and vibration cond-itions into consiaera*ion. Fr~m the above, according-to the compound carburetor of the present invention, the transit from the primary side to the secondary side can be made very smooth Furthex, the length of the sPcondary slow-running mixture path 9 is so short that substantially no air locking phenomenon will be generated byl:the temperature rise or the like. Therefore, the total volume of the secondary slow-running fuel systems can be made so small and the number of bends of the secondary slow-running mixture path 9 can be made so few that the passage resistance will reduce, the transit delay and unstable jetting of the mixture will be eliminated and, a~ a result, the response characteristic will improve. Further, as the secondary slow-running mixture path g is connected through the pipe 10 in the course, the freedom of the equipment will increase.
In the above mentioned embodiment, the secondary slow-running fuel systems are provided independently for the respective cylinders. However, even if one secondary slow-running fuel system is provided independently for two cylinders so as to serve the two cylinders, the same effect will be able to be obtained. This formation is very advantageous as to the cost.
.
Claims (7)
1. A compound carburetor comprising a primary bore provided therein with a primary throttle valve and branched in the downstream part of said primary throttle valve to be respectively connected to a plurality of cylinders of an engine, a secondary bore arranged adjacently to said primary bore and branched in the downstream part to be respectively connected to said plurality of cylinders through secondary throttle valves arranged respectively for said plurality of cylinders, and a plurality of secondary slow-running fuel systems set respectively independently for said plurality of cylinders, opened respectively in the vicinity of said respective secondary throttle valves, and cooperating res-pectively with said respective secondary throttle valves.
2. A compound carburetor comprising a primary bore provided therein with a primary throttle valve and branched in the downstream part of said primary throttle valve to be respectively connected to a plurality of cylinders of an en-gine, a secondary bore arranged adjacently to said primary bore and branched in the downstream part to be respectively connected to said plurality of cylinders through secondary throttle valves arranged respectively for said plurality of cylinders, and a plurality of secondary slow-running fuel systems set respectively independently for a pair of cylinders among said plurality of cylinders, opened respec-tively in the vicinity of said respective secondary throttle valves, and cooperating respectively with said respective secondary throttle valves.
3. A compound carburetor according to claim 1, wherein said secondary slow-running fuel system comprises a secondary slow-running fuel path, a secondary slow-running jet set in said secondary slow-running fuel path, a secondary slow-running air jet set in connection with said secondary slow-running jet, and a secondary slow-running mixture path communicating with said secondary slow-running jet and secondary slow-running air jet and opened within said cylinder adjacently to said secondary throttle valve.
4. A compound carburetor according to claim 3 wherein said secondary slow-running mixture path includes a pipe airtightly fitted at one end to one part of the carburetor body and at the other end to the other part.
5. A compound carburetor according to claim 4 wherein said pipe includes O-rings made of an elastic sealing material and fitted respectively to both ends.
6. A compound carburetor according to claim 4 wherein said pipe is made of an elastic sealing material and has ribs respectively at both ends.
7. A compound carburetor according to claim 4 wherein said pipe is made of an adiabatic material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000390867A CA1166099A (en) | 1981-11-25 | 1981-11-25 | Compound carburetor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000390867A CA1166099A (en) | 1981-11-25 | 1981-11-25 | Compound carburetor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1166099A true CA1166099A (en) | 1984-04-24 |
Family
ID=4121494
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000390867A Expired CA1166099A (en) | 1981-11-25 | 1981-11-25 | Compound carburetor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1166099A (en) |
-
1981
- 1981-11-25 CA CA000390867A patent/CA1166099A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |