JP3965602B2 - Retrofit silencer - Google Patents

Description

  The present invention relates to a rear muffler to which a muffler of an internal combustion engine is attached.

  Conventionally, a muffler of an internal combustion engine provided with a valve that opens and closes by exhaust gas pressure has already been disclosed. For example, an exhaust noise silencer disclosed in Patent Document 1 is provided with a valve that is elastically applied so as to be normally closed at the tip of a muffler tail pipe, and idling between this valve or between this valve and a valve seat. An exhaust passage dedicated to the hour is provided, and the cross-sectional area of the exhaust passage is determined as small as possible within a range where idling operation can be continued.

The silencer of the internal combustion engine disclosed in Patent Document 2 is designed to reduce the noise in the low speed rotation range of the internal combustion engine and maintain the output in the high speed rotation range at the same time. In the case where the rear end is provided with a small-diameter pipe portion, the pipe portion is provided with an exhaust gas flow path adjustment mechanism for adjusting a cross-sectional area of the exhaust gas flow path according to the exhaust gas pressure. .
Japanese Utility Model Publication No. 54-10137 JP-A-10-280939

  However, conventionally, in order to obtain the effects shown in Patent Documents 1 and 2 described above, it was necessary to replace the muffler itself, which caused a problem of increasing costs.

  For this reason, the present invention achieves a sufficient noise reduction in the low-speed rotation range of the internal combustion engine by attaching a muffler of a normal internal combustion engine, and a post-installed muffler that maintains a sufficient output in the high-speed rotation range. Is to provide.

  Therefore, the rear muffler of the present invention includes a mounting holder that is inserted into the tail pipe of the muffler of the internal combustion engine and is fixed to the tail pipe via the fixing means, and an inner tube holder that extends from the holder. An inner tube supported by the inner tube holder; a valve holding portion that is formed integrally with the mounting holder and defines a bypass opening between the inner tube; and the inner tube and the mounting holder. A guide valve that is slidable on the outer periphery of the inner tube and that opens and closes the bypass opening by contacting the valve holding portion, the valve holding portion and the inner An elastic means disposed between the tube holders and pressing the guide valve against the valve holding portion with a predetermined force. There is to be. The inner pipe preferably extends a predetermined length inward of the tail pipe and defines a buffer space between the tail pipe and the tail pipe.

  As a result, the muffler is improved by the buffer space defined between the inner tube and the tail pipe in the low-speed rotation range simply by inserting the rear muffler into the tail pipe of the muffler of the internal combustion engine and fixing it. In addition, the exhaust gas pressure presses the guide valve against the elastic means in the high-speed rotation range, and the bypass opening opens, so that the buffer space and the bypass space communicate with each other, and the inside of the tail pipe Since the exhaust gas is exhausted to the outside air as it is, the output in the high rotation range is maintained without excessively increasing the exhaust resistance.

  Therefore, according to the present invention, it is possible to achieve sufficient noise reduction in the low-speed rotation range of the internal combustion engine and maintain sufficient output in the high-speed rotation range by simply mounting and fixing the rear muffler in the tail pipe of the muffler. Therefore, it is possible to reduce the labor and cost of parts replacement. Also, by changing the size of the mounting holder, it is possible to adapt the muffler of various car models.

  Embodiments of the present invention will be described below with reference to the drawings.

  A retrofit silencer 1 according to an embodiment of the present invention includes, for example, an inner tube 2 having a predetermined length and a tail pipe 11 of the muffler 10 of the internal combustion engine shown in FIGS. A mounting holder 3 mounted in the enlarged diameter end portion 12, an inner tube holder 4 provided between the inner tube 2 and the mounting holder 3, and holding the inner tube 2, and an outer periphery of the inner tube 2 A guide valve 5 slidably disposed on the surface, a valve holding portion 3 a provided to extend from one end of the mounting holder 3, and to which the guide valve 5 abuts, the guide valve 5 and the inner A spring 6 is provided between the tube holder 4 and presses the guide valve 5 against the valve holding portion 3a with a predetermined force.

  As shown in FIG. 2 and FIG. 3, the rear silencer 1 having the above-described configuration is formed by screwing a screw 8 into the screw hole 7 provided in the mounting holder 3 through the tail pipe 11. The rear muffler 1 is attached to the tail pipe 11. As a result, a buffer space 14 is defined between the inner tube 2 of the rear muffler 1 and the tail pipe 11. For example, as shown in FIG. Since the bypass opening 18 (shown in FIG. 3) is closed by contacting the valve holding portion 3a, a part of the exhaust gas discharged from the internal combustion engine collides with the buffer space 14 via the exhaust gas passage 13. Then, since it is discharged to the outside air 16 through the internal space 15 of the inner pipe 2, a great silencing effect can be obtained.

  Further, in the high rotation range of the internal combustion engine, the exhaust gas pressure opposes the pressing force of the spring 6 and pushes the guide valve 6 to the bypass space 17 side, so that the guide valve 6 is bypassed as shown in FIG. Since the opening 18 is opened, the exhaust gas that reaches the buffer space 14 passes through the bypass space 17 via the bypass opening 18 and is discharged to the outside air 16, so that the exhaust resistance of the exhaust gas is reduced. It is possible to suppress a decrease in output in the high rotation range. In addition, this makes it possible to prevent an abnormal increase in exhaust pressure in the high rotation range.

  The diameter and shape of the mounting holder can be changed in accordance with the shape of the tail pipe of the muffler, and the inner tube holder has three radially extending support portions in the above embodiment. Although it is configured, the shape is not particularly specified as long as the inner tube is held and ventilation is appropriately performed.

The structure of the back muffler which concerns on the Example of this invention is shown, (a) is the sectional drawing, (b) is a front view. It is the sectional view showing the state where a back muffler was installed, and showing the state in the low rotation region especially. FIG. 2 is a cross-sectional view showing a state in which a retrofitted silencer is mounted, particularly in a high rotation range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Retrofit muffler 2 Inner tube 3 Mounting holder 3a Valve holding part 4 Inner tube holder 5 Guide valve 6 Spring 7 Screw hole 8 Screw 10 Muffler 11 Tail pipe 12 Expanded end 13 Exhaust gas passage 14 Buffer space 15 Internal space 16 Outside air 17 Bypass space 18 Bypass opening

Claims (2)

A mounting holder inserted into the tail pipe of the muffler of the internal combustion engine and fixed in the tail pipe via fixing means;
An inner tube holder extending from the holder;
An inner tube supported by the inner tube holder;
A valve holding part that is formed integrally with the mounting holder and defines a bypass opening with the inner tube;
A guide valve that is disposed in a bypass space defined between the inner tube and the mounting holder, is slidable on the outer periphery of the inner tube, and opens and closes the bypass opening by contacting the valve holding portion When,
An after-mentioned muffler comprising an elastic means disposed between the valve holding portion and the inner tube holder and pressing the guide valve against the valve holding portion with a predetermined force.   The rear muffler according to claim 1, wherein the inner pipe extends a predetermined length inward of the tail pipe and defines a buffer space between the inner pipe and the tail pipe.

Images