JPS599089Y2 - Air cleaner device for internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake pipe attached to an air cleaner of an internal combustion engine.

More specifically, the intake pipe has an inlet part and an outlet part that open to the inside and outside of the air cleaner case, and the diameter of the approximately central part is made small so that the inlet part and the outlet part are continuous in a curved line.
By providing a small-diameter constricted part between the outlet parts, the flow resistance during air introduction is reduced, thereby increasing the amount of intake air, improving intake efficiency, and increasing the output of the internal combustion engine. Regarding a cleaner device.

Conventional intake pipes attached to air cleaners of internal combustion engines have generally been straight pipes with a trumpet-like opening at the tip end and continuous lengthwise diameters of approximately the same diameter.

In conventional air intake pipes, when air flows and is taken into the air cleaner, there is pipe wall resistance, so the calculated opening cross-sectional area and the effective opening cross-sectional area through which the air actually flows are large. It makes a difference.

This difference increases as the length of the intake pipe increases, and as the flow resistance increases, it is not always possible to obtain the expected amount of intake air.

If the amount of intake air decreases, the output of the internal combustion engine will naturally decrease, and the amount of air that can be taken in through the intake pipe will affect the performance of the internal combustion engine itself.

On the other hand, in order to increase the amount of air flowing through the intake pipe, it is possible to increase the diameter of the intake pipe and increase the opening cross-sectional area. If the cross-sectional area of the opening is increased, the intake noise becomes louder, which causes problems in terms of noise countermeasures.

The inventor of the present invention has developed the present invention in order to effectively solve the problems in conventional intake pipes as described above.

The purpose of the present invention is to change the shape of the intake pipe attached to the air cleaner case into a nozzle shape by reducing the inner diameter of the approximately central portion between the inlet and the outlet so as to reduce the flow resistance during air circulation. A constricted part is provided between the inlet and outlet parts, and this constricted part with a small diameter is connected to the inlet and outlet parts with a large diameter by a curved inner peripheral wall, thereby reducing pipe wall resistance and flow resistance. To provide an air cleaner device for an internal combustion engine, which aims to increase the amount of intake air and improve the output of the internal combustion engine, and achieves the above without increasing the cross-sectional area of the opening, thereby exhibiting a muffling effect on intake noise. do.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

The drawing shows a cross-sectional view of a part of the air cleaner and a part of the carburetor.A cylindrical element holder 2 is built into the air cleaner case 1 with one end protruding from the case 1. An air cleaner element 3 for removing dust and the like from the air is attached to the air cleaner element 3.

A connector tube 6 that connects the case 1 to the carburetor 5 connected to the internal combustion engine 40 is fitted to the front part 2b of the element holder 2, which is tightly sealed to the cleaner case 1 by the dust seal 4. The chew 116 is fastened to the protruding front portion 2b of the holder 2 and the carburetor 5.

After dust and the like are removed from the air in the cleaner case 1 by the air cleaner element 3, the air enters the element holder 2 through the hole 2C and is fed to the carburetor 5 via the tube 6.

An intake pipe 8 for introducing outside air into the inner chamber of the case 1 is attached to the air cleaner case 1, and a flange 8a formed on the outer circumferential surface of the central portion in the longitudinal direction is fitted and locked to the case 1 to form an inlet section. 9 is made to protrude to the outside of the case 1, and the outlet part 10 is made to face the inside of the case 1.

The inner diameter dimension d at the inlet part 9 of this intake pipe 8 and the outlet part 1
The inner diameter dimension d2 at 0 is approximately equal, and these 9
, 10, the inner diameter of the intake pipe 8 is reduced approximately at the center of the intake pipe 8.

By doing this, a constricted part 11 with a narrowed diameter is provided approximately at the center, and from the constricted part 11 to the inlet part 9 and the outlet part 1.
The diameter is gradually increased toward the 0 side, and the shape expands symmetrically to the artificial part 9 and the outlet part 10 with the constricted part 11 as a boundary, and the curved inner peripheral wall 8b allows the inlet part 9, the constricted part 11, and the outlet part 10 to be expanded. are connected, and the inner circumferential wall 8b of the intake pipe 8 is made into a curved surface.

As described above, the opening cross-sectional area of the throttle part 11 can be minimized, and the inner diameter of the throttle part 11 is desirably about 0.65 to 0.85 times the inner diameter dimensions d1 and d2 of the inlet part 9 and the outlet part 10.

When the intake pipe 8 introduces air into the air cleaner case 1, since the small-diameter ridged part 11 is provided approximately in the center and the overall shape is nozzle-like, the pipe wall resistance of the inner circumferential wall 8b is reduced, and the intake pipe 8 Smooth circulation of air within the pipe 8 is ensured,
The difference between the calculated opening cross-sectional area and the effective opening cross-sectional area is small;
Therefore, a large amount of air can be sucked into the case 1, and the suction efficiency is improved.

By the way, if we change our point of view and consider the pressure in the inner chamber of the air cleaner case 1, we will see that due to the opening and closing operations of the intake valve of the internal combustion engine 40, the pressure in the case 1 remains constant until the next intake valve opening operation. , pulsating alternately between negative and positive pressure.

On the other hand, when viewed from the internal combustion engine 40 side, it is desirable that the pressure inside the case 1 be the same as atmospheric pressure or positive when the intake valve is opened. ．． Generally, the pressure inside the case 1 is negative pressure.

In such a case, when the intake pipe 8 according to the present invention is used, the inflow resistance inside and outside the case 1 is small, so the negative pressure is quickly attenuated, and the pressure inside the case 1 approaches atmospheric pressure. When the intake valve is opened, the pressure inside the case 1 is more likely to return to a state that can contribute to improving the suction efficiency compared to the conventional intake pipe, so the suction efficiency can be improved and the output can be increased.

As described above, an internal combustion engine driving test was conducted using the intake pipe 8 in which the opening areas of the inlet part 9 and the outlet part 10 were made approximately equal, and the throttle part 11 was provided approximately at the center of the length l. 1
Values of 7.8 Ps and torque 1.57 kg-m were obtained,
Output 17.4Ps and torque 1.53 obtained when a straight pipe type conventional intake pipe is installed on the same internal combustion engine.
The experimental value was better than that of kg-m, proving the excellence of the present invention.

In this case, the aperture cross-sectional area in the aperture portion 11 is 14.5
cm', the opening cross-sectional area of the conventional intake pipe was 16.5 cm''.

In this way, even if the opening area is made smaller than before, it is possible to improve the output of the internal combustion engine, increase the amount of air introduced into the air cleaner case 1, and reduce the intake noise when air is introduced by reducing the opening area. It is possible to more effectively reduce the amount of noise, thereby simultaneously improving the intake efficiency and the noise reduction effect imposed on the intake pipe, and is also effective in noise countermeasures.

As is clear from the above explanation, according to the present invention, a constricted portion with an inner diameter smaller than these is provided approximately at the center of the inlet and outlet portions of the intake pipe, so that the wall resistance of air flowing through the intake pipe is reduced. As a result, the amount of air taken into the air cleaner can be increased, improving intake efficiency and contributing to an increase in the output of the internal combustion engine.

Furthermore, since the above is not achieved by increasing the opening area of the intake pipe, it is possible to exert a muffling effect on the intake noise generated when air flows through the intake pipe, and the intake pipe according to the present invention Since the opening cross-sectional area of the tube can be made smaller than before, it is possible to improve the silencing effect of intake noise, and it exhibits various features such as improving intake efficiency and being advantageous in terms of noise countermeasures.

[Brief explanation of drawings]

The drawing is a sectional view of a portion of the air cleaner case and carburetor. In the drawing, 1 is the air cleaner case, 8 is the intake pipe, and 9 is the air cleaner case.
10 is an inlet portion, 10 is an outlet portion, and 11 is a constriction portion.

Claims (2)

[Scope of utility model registration request] (1) A diaphragm that opens inside and outside the air cleaner case, has an inlet and an outlet with approximately equal opening diameters, and has an inner diameter relatively smaller than the opening diameter approximately in the center between the opening and the outlet. 1. An air cleaner device for an internal combustion engine, comprising an intake pipe having a constricted portion, an inlet portion, and an outlet portion connected to each other by an inner circumferential wall having a curved surface. (2) The air cleaner device for an internal combustion engine according to claim 1, wherein the inner diameter of the throttle portion is 0.65 to 0.85 times the opening diameter of the inlet and outlet portions.