JPS5939174Y2 - Internal combustion engine intake system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an intake device for an internal combustion engine used in a motorcycle or the like.

More specifically, a constricted part with a smaller cross-sectional area than other parts is provided in the air passage connecting the fuel supply device such as a carburetor and the air cleaner, and the cross-sectional area of the air passage including this small diameter constricted part is smoothed. The present invention relates to an intake system that improves the output of an internal combustion engine, particularly in the low rotation range.

It is known that it is possible to improve the output of an internal combustion engine by improving its intake efficiency, and one way to do this is to set the total length of the air cleaner, carburetor, and intake pipe that connects them as long as possible. It is known that the pulsation effect of the engine increases the volumetric efficiency and improves the output in the low and medium speed range.

This method requires a long intake pipe, so
This is not optimal for small-sized, small-displacement motorcycles because their length is restricted due to space and appearance issues.

The inventors of the present invention came up with the present invention as a result of various studies in order to effectively improve the output of internal combustion engines such as motorcycles in the low and medium speed ranges.

The purpose of the present invention is to provide a constricted portion with a smaller diameter than other portions in the intake passage connecting the air cleaner and the fuel supply device, and to smoothly change the cross-sectional area of the intake passage including this constricted portion. The present invention provides an intake system for an internal combustion engine.

The purpose of the present invention is to provide an intake system that can improve the intake efficiency of the engine and increase the output due to the inertia effect caused by the presence of the throttle part, and also to provide an intake system that is smaller in size and has a smaller displacement. Even if there are space and design constraints on increasing the length of the intake pipe, such as in motorcycles, it is possible to effectively improve output by using the intake pipe with a limited length. To provide an intake device which achieves the above by forming the middle part of the pipe to a small diameter, and which has a simple structure and can be implemented without making any changes to a conventional intake system.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a side view of the main parts of a motorcycle in which the present invention has been implemented. 1 is the main pipe of the frame, and a head tube 2 is fixedly installed at the front end, which controls the front fork 3 that supports the front wheel. Supports Mukaiji H.

Middle part K of frame main pipe 1 (ri engine 4,
Units such as mission 5 are mounted and supported, and engine 4
The intake port is an intake pipe 6 and a carburetor 7 is a fuel supply device.
connected to the downstream end opening of the

On the other hand, an air cleaner 8 is installed at the front of the main pipe 1 via a bracket or the like, and the suction pipe 8a of the air cleaner 8 and the upstream end 7a of the carburetor 7 form a connecting tube with an air passage formed inside. They are directly connected through an intake pipe 10.

Details of the intake pipe 10 are shown in FIGS. 2 to 6, with FIG. 2 showing a side view of the entire intake pipe.

The intake pipe 10 is made of an elastic material such as rubber to absorb dimensional errors during manufacturing and to prevent the transmission of engine vibrations, which makes the vehicle heavier. has recesses 11a and 12a surrounding it, and one end 11 is fitted into the end of the suction pipe 8a, the other 12 is fitted into the upstream end of the carburetor 7, and a band is inserted into the recess 11a=12a. 9, 9 and tighten and connect.

In this embodiment, the mounting portions 11 and 12 are oriented approximately 90 degrees apart, so that the intake pipe 10 has an elbow shape as a whole.

The lower part of the transfer section 11 on the upstream side has an oval tubular shape as shown in FIG. 4, and thereafter the cross section is circular.

The intermediate portion 13 between the mounting portions 11 and 12 is curved into an L shape, and a plurality of reinforcing ribs 14 for increasing rigidity are provided on the outer periphery.

The most important thing is that the central part of the intermediate part 13 is made smaller in diameter than the other parts, and a substantially constricted part 15 is formed in the central part of the tube that connects with other parts.

The diameter of the small-diameter constricted portion 15 is made to gradually increase toward the upper and downstream ends, and the cross-sectional area of the passage in the intake pipe 10 including the intermediate portion 13 and the upper and downstream ends changes smoothly. Also, the curvature of the intermediate portion 13 is set so that it changes smoothly, reducing the resistance to air flow, and making the air flow smooth.

In this embodiment, the minimum diameter portion is 60φ to 70 mm, which is the maximum diameter cross section of the carburetor side attachment portion.

As a result of the above, the passage connecting the air cleaner 8 and the carburetor 1 has a narrowed portion with a small diameter, and the cross section of the passage smoothly gradually decreases and increases.

In the above, although the existence of the intake pipe 10 can improve the suction efficiency as described above due to the pipe length effect, the intake pipe 10
Since the constriction part 15 is provided in the middle part of the pump, the suction efficiency is improved due to the inertia effect due to the Henchuri action or the like.

In particular, in the same table, two motorcycles with a displacement of 50 cc and a 4-cycle engine are compared, each with an intake system using an intake pipe with the same cross-section and another with a throttle section provided in the middle as in the present invention. Significant increases in output were seen in engines equipped with the intake system devised by Wood.

That is, 400Or − with 5QeC, 4-stroke engine
Under condition F of p - m, the torque of the conventional means is 0.275 kg.
/m, but according to the present invention it is 0.31
It became clear that the torque increased by about 20 kg/m, and the output could be improved in the low and medium rotation range.

Although the illustrated example has been described above as an embodiment applied to an internal combustion engine of a motorcycle, it goes without saying that the present invention can be implemented arbitrarily regardless of the size of the internal combustion engine, and is not limited to use in motorcycles.

As is clear from the above, according to the present invention, a constriction part is provided in the air passage connecting the fuel supply device connected to the intake pipe of the internal combustion engine, that is, the carburetor, and the air cleaner, and the air passage including the constriction part is Since the air passage is formed with a smoothly changing cross-sectional area, it is possible to give an inertial effect to the intake air in the low and medium speed range of the internal combustion engine, and to enhance the pulsation effect caused by opening and closing of the engine's intake port. Therefore, the volumetric efficiency of intake air can be increased, and an output improvement in the low and medium rotation range can be achieved.

Moreover, as described above, inertia force is applied to the intake air itself, and the fuel is mixed downstream, so it is possible to improve the output in the low and medium rotation range without making any changes to the fuel supply system. can be achieved.

As mentioned above, we achieved the above with a simple structure and without increasing the length of the intake passage, and applied it to small and small displacement motorcycles where there are many constraints in terms of space and design. It is possible to improve the output of the engine, and it is possible to obtain a simple and effective means for increasing the output, which is highly practical.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of the main parts of a motorcycle, Fig. 2 is an enlarged side view of the intake pipe, and Figs. It is a sectional view taken from line -3 to line 6-6. In the drawing, 4 is an internal combustion engine, 7 is a carburetor, 8 is an air cleaner, 10 is an intake pipe forming an air passage, and 5 is a constriction portion.

Claims (1)

[Scope of utility model registration request] A constriction part whose cross-sectional area is smaller than other parts is provided in the air passage upstream of the fuel supply device connected to the intake pipe of the internal combustion engine and downstream of the air cleaner, and the cross-sectional area of the air passage including the constriction part is An intake device for an internal combustion engine, characterized in that it is formed by smoothly changing the shape of the air.