Mechanism for coordinating operation of throttle valves in a carburetor system

Abstract: A mechanism for coordinating the operation of throttle valves (15) in a carburator system is provided. A plurality of carburetors (11) are connected in series and are arranged in parallel with one another so as to position shafts (13) thereof in parallel with one another. The throttle valves (15) are turned on the shafts (13) to open or close passages. Each of the carburetors (11) connected in series shares one shaft (13) which is received in bearings (14) positioned at opposite ends thereof. A link (19) extends between the shafts (13) of the carburetors (11) arranged in parallel and coordinates the operation of the shafts (13) of the carburetors (11).

Description: The present invention relates to a mechanism for coordinating operation of carburetor throttle valves in a multi-cylinder internal combustion engine, for example. Conventional carburetors used in multi-cylinder internal combustion engines employ a mechanism similar to that shown in an example of Figure 3 to coordinate operation of throttle valves. Figure 3 is a plan view of the carburetor arrangement used in a V-type 4 cylinder internal combustion engine. Numeral 1 indicates the top edge of the internal combustion engine. Numeral 3 indicates the carburetors provided on top of each of the cylinders. Numeral 4 indicates throttle valves. These throttle valves 4, supported on the shafts 5 so as to be arranged across the individual carburetors 3, open and close with the rotation of the shafts 5. Also, adjacent pairs of carburetors 3 are arranged in series such that the shafts 5 are coaxial. Furthermore, these carburetors 3 are juxtaposed such that their shafts 5 are parallel to each other. Still, in the case of the above conventional carburetors 3, each shaft 5 is rotatably supported in bearings 6 provided on it's opposite ends. Furthermore, the tips of adjacent shafts 5 protrude from the bearings 6, and are connected to each other by operation coordinating mechanisms 7a and 7b provided at the tips the of shafts 5. Also, to one of these shafts 5 (the lower right shaft in Fig. 3) is attached a drive mechanism 8. The rotation of this shaft (driving shaft) 5 is transmitted, via the link 9 extending between the tips of the shafts 5 protruding from the bearings 6, to the shafts 5 (driven shafts) of the carburetors 3 arranged in parallel to the carburetors on the driving side. That is, in the conventional carburetor 3, when the shaft 5 in the lower right of the figure is rotated by the drive mechanism 8, the rotation is transmitted to the shaft 5 (the upper right shaft in the figure) by the operation coordinating mechanism 7a, and then to one of the driven shafts (the upper left shaft) 5 via the link 9 then, by the operation coordinating mechanism 7b, to the shaft 5 (the lower left shaft). As a result, the shafts 5 rotate together by an equal amount, and open or close the throttle valves 4, thereby controlling the volume of air delivered to each of the cylinders. Carburetor systems of the type mentioned above which comprise a mechanism for coordinating the operation of throttle valves are known from US-A-5 101 792 and GB-A-2 237 900. However, in the above conventional throttle valve operation coordinating device, the link 9 extends between the tips of the shafts 5. Therefore, the link 9 is supported in a cantilever fashion by one end of the shaft 5. Particularly on the driven shafts 5, when rotation is transmitted through the link 9, the shaft 5 is pushed by the link 9 as shown by the arrow M in the figure, causing a swing left or right with the bearings 6 acting as a fulcrum. The possibility exists that the motion of the link 9 would not be converted into the rotation of the shafts 5 correctly. Therefore, in the above conventional throttle valve operation coordinating device, to prevent the swing of the shafts 5 in the driven side carburetor 3 and the nonuniformity of opening and closing amount and opening and closing time of the throttle valves 4 attached to them, despite the high cost, it is necessary to use bearings 6 to hold the shafts 5 firmly. An object of the present invention, taking into account the above situation of the related art, is to provide an inexpensive mechanism for allowing smooth and reliable operation of the throttle valves of the driven side carburetors. The present invention is characterized by the features of claim 1. The object of the present invention is to provide a mechanism for coordinating the operation of throttle valves in a carburetor system in which a plurality of carburetors are connected in series and are then arranged in parallel with one another so as to position shafts thereof in parallel with one another, and throttle valves are turned on the shafts to open or close passages. Each of the carburetors connected in series shares one shaft which is received in bearings positioned at opposite ends thereof, and a link extends between the shafts of the carburetors arranged in parallel and coordinates the operation of the shafts of the carburetors. With this throttle valve operation coordinating mechanism, both ends of the shafts supporting the link are received in their respective bearing, so that the link is supported at its opposite ends and the stability of the shafts can be increased. It follows that, when rotation is transmitted by the link, the driven shafts do not sway left or right even though they are pushed by the link. Further, carburetors arranged in series may be formed as one integral part in order to improve the rigidity and support precision of the shafts. The present invention concerning the throttle valve operation coordinating mechanism will be described below based on the attached drawings. Fig. 1 is a sectional view showing the carburetor throttle valve operation coordinating mechanism according to the invention. Fig. 2 is a partial sectional view of the carburetor throttle valve operation coordinating mechanism, taken along line II-II in Fig. 1. Fig. 3 shows an example of a conventional carburetor throttle valve interlocking mechanism. The throttle valve operation coordinating mechanism shown in Figure 1 and Figure 2 is applied to carburetors used in a V-type 4 cylinder internal combustion engine. Figure 1 is a cross section of the carburetors, depicted assuming that the axes thereof extend in parallel to the plane of Figure 1. Numeral 11 indicates the carburetors provided at the top of each of their respective cylinders (not shown). These carburetors 11 are cylindrical and the adjacent pair of carburetors 11 are arranged in series similar to the above mentioned conventional carburetors 3. Also, adjacent carburetors 11 are coupled together via pairs of stays 12a and 12b. Each of shafts 13 extends through carburetors connected in series, and is rotatably supported at its end in a bearing 14 provided at one end of one of carburetors connected in series. A pair of carburetors 11 are connected in series with the shaft partially exposed therebetween. Throttle valves 15 are supported by shafts 13 inside the carburetors 11 similarly to the above conventional throttle valves 4, and open or close in response to the rotation of the shafts 13. Also, the above pairs of carburetors 11, similarly to the above conventional carburetors 3, are juxtaposed such that the shafts 13 are parallel to each other. Collars 16 are mounted on the exposed parts of the shafts 13 between the adjacent carburetors 11. The collars 16 are fixed onto the shafts 13 by screws 17 etc. Connecting tabs 16a extend radially from the collars 16. Pins 18 parallel to the shafts 13 are fixed to the connecting tabs 16a. Further, a link 19 extends between the pins 18 of the juxtaposed carburetors 11. A drive mechanism 20 is connected to one of the shafts 13 (i.e. the driving shaft at the right side in the figure) of the carburetor in order to rotate the shaft 13. In the foregoing carburetor 11, if the shafts 13 on the right side of the figure are rotated by the drive mechanism 20, the throttle valves 15 on the right side of the figure turn on the shaft 13 to open and close a passage. The rotation of the shaft 13 is transmitted via the connecting tabs 16a, pins 18, and link 19 to the driven shaft 13 in the carburetor 11 on the left side in the figure. As a result, this throttle valve operation coordinating mechanism also rotates the shaft 13 on each of the carburetors 11 and the throttle valves 15 open or close the passages by equal amounts, thereby controlling the volume of air delivered to each of the cylinders. In the throttle valve operation coordinating mechanism of the present invention, ends of the shafts 13 are supported in the respective bearings 14 formed in the carburetors 11. Furthermore, the link 19 extends between the longitudinal centers of the shafts 13 and the link 19 becomes supported at its opposite ends, so that the stability of the shafts 13 is improved. It follows that, when rotation is transmitted by the link 19, the driven shaft 13 will not swing left or right even though it is pushed by the link 19. As a result, even without providing new bearings etc., the motion of the link 19 is correctly converted into the rotational force for the driven shaft 13. The throttle valves in the driven carburetors 11 can be realized at a low cost, and assure smooth and precise operation. Furthermore, the carburetors 11 include the stays 12a and 12b as integral parts, so that the rigidity of the carburetors 11 and the positional precision of the bearings 14 can be increased, and the operation of the throttle valves 15 also becomes more accurate. According to the present invention, in the throttle valve operation coordinating mechanism, both tips of the shaft supporting the link are supported in their respective bearings. The link is supported at its ends by the shafts, so that the stability of the shaft is improved. It follows that, when rotation is transmitted by the link, the driven shaft will not swing left or right even though it is pushed by the link. As a result, even without providing new bearing etc., the link reliably converts its motion to the rotational force for the driven shaft. The throttle valves in the driven carburetors can be produced at a reduced cost, and can assure smooth and precise operation. Also, when carburetors to be connected in series are formed as an integral part, the rigidity of the carburetors and the support precision of the shafts can be improved, and the operation of the throttle valves becomes more accurate. A mechanism for coordinating the operation of throttle valves (15) in a carburator system is provided. A plurality of carburetors (11) are connected in series and are arranged in parallel with one another so as to position shafts (13) thereof in parallel with one another. The throttle valves (15) are turned on the shafts (13) to open or close passages. Each of the carburetors (11) connected in series shares one shaft (13) which is received in bearings (14) positioned at opposite ends thereof. A link (19) extends between the shafts (13) of the carburetors (11) arranged in parallel and coordinates the operation of the shafts (13) of the carburetors (11).

Claims: A carburetor system comprising a first and a second plurality of carburetors (11) connected in series and a mechanism (16, 19) for coordinating the operation of throttle valves (15) of said pluralities of carburetors (11), wherein each of said carburetors (11) connected in series shares one common shaft (13) which is received in bearings (14) positioned at opposite ends thereof, and the throttle valves (15) are turned on said shaft (13) to open or close passages, wherein the first and second pluralities of carburetors (11) are arranged in parallel with one another so as to position said shafts (13) in parallel, and wherein a link (19) extends between said shafts (13) of said first and second pluralities of carburetors (11) arranged in parallel and coordinates the operation of said shafts (13) of said carburetors (11), characterized in that said link (19) extends between the longitudinal centers of said shafts (13). The carburetor system of claim 1, wherein said carburetors (11) connected in series are formed as an integral member.

Inventors: AKAGI TAKASHI, IWAO SUMINARI, AKAGI, TAKASHI, IWAO, SUMINARI
Applicants: HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 1998
Main classification: F02M13
IPC codes: F02D9, F02M13, F02M35