JPH0573891B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention [Field of Industrial Application] The present invention is directed to a method of dividing a plurality of silencing chambers using a partition plate and communicating each chamber through a connecting pipe. This invention relates to a silencer for internal combustion engines for vehicles that undergo frequent changes.

[Conventional technology]

With the above-described configuration, a sound reduction effect is obtained by combining silencing elements such as expansion, interference, resonance, and sound absorption. In that case, in addition to the internal structure of the silencer, the lengths and ratios of the exhaust inlet pipe, exhaust tail pipe, and silencer interconnection pipe, as well as the mounting position of the silencer in the entire exhaust system, play a major role. (Refer to Japanese Patent Publication No. 59-14603 and Japanese Utility Model Application Publication No. 163422/1983).

[Problem that the invention seeks to solve]

However, with a silencer manufactured based on a design, the length of the sound, the pipe diameter, the mounting position of the silencer, etc. are fixed and cannot be changed.

On the other hand, in vehicles such as automobiles and motorcycles, where the engine speed constantly fluctuates and the exhaust noise conditions change, it is desirable to be able to take noise countermeasures according to the driving conditions. This is not possible with a silencer.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide a muffler that can provide noise countermeasures in accordance with engine operating conditions with a simple configuration.

B. Structure of the Invention [Means for Solving Problems] The present invention provides a muffler for an internal combustion engine which is divided into a plurality of muffling chambers using a partition plate and communicated with each chamber via a connecting pipe. , the joint pipe is a double pipe to form an exhaust passage between the inner and outer pipes, one pipe is fixed to the partition plate or end plate of the muffler body, and the other pipe is extended to the outside of the muffler body. The internal combustion apparatus is characterized in that the movable pipe is movable to close the extension end, and the movable pipe is moved in and out to change the total pipe length of the double pipe, and at the same time, the arrangement interval of the sectional silencing chambers can be substantially changed. It is an engine silencer.

[Effect]

By making the joint pipe in the silencer a double pipe, one of which is fixed and the other of which is movable, inside and outside, and by manually or automatically moving the movable pipe in and out, the total pipe length and the arrangement distance of the sectional sound-muffling chambers are made variable. Noise countermeasures are taken according to engine rotation.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which the exhaust gas entering from the inlet pipe 2 is connected to the first expansion chamber 3 - the connecting outer pipe 4.
→ Inner pipe 5 → Second expansion chamber 6 → Joint pipe 7 → Third expansion chamber 8 → Joint outer pipe 9 → Exhaust tail pipe 10 which is the inner pipe
is discharged from. Note that the double pipe configuration is not limited to the illustrated example, and any combination pipe may be selected.

The above-mentioned joint pipes 4, 5, 9, and 10 constitute a double pipe according to the present invention, and the inner pipe 5 is fixed to the partition plate 12, the tail pipe 10 is fixed to the rear end plate 14, and the inner pipe 5 and the partition are fixed to the rear end plate 14. The outer tube 4 that can be slid on the plate 13 and the rear end plate 14 is led out from the end plate 14 to the outside of the muffler body 1, and the end 4a
occlude. The outer tube 9 of the other double tube is the front end plate 1
1 to the outside of the silencer, and its end plate 11.
It is slidable on the partition plates 12 and 13 and has a closed end 9a.

The outlet ports from the end plates 14, 11 of the movable tubes 4, 9 are covered with heat-resistant silicone rubber 15, for example, as shown in FIG. 2, and are held down with coil spring rings 16 to prevent gas leakage.

FIG. 3 shows the above configuration separately. When the movable tube 4 is moved in and out of the movable tube 5, the total length of the inner tubes 4 and 5 changes, and at the same time, the total length of the inner tubes 4 and 5 changes. The interval L also changes. Also, replace tube 9 with tail tube 1.
Moving it forward or backward relative to 0 will change the length of the tail pipe. Therefore, noise countermeasures can be easily implemented depending on the engine rotational speed, etc.

Note that the connecting pipe 7 and the introduction pipe 2 may also be subjected to a similar double pipe processing, and the selection is made as appropriate depending on the design.

On the closed side of the movable tube, an expansion chamber 22 is formed that widens toward the tip as shown in FIG. 4 to provide an expansion chamber effect, or a tapered chamber 23 is formed as shown in FIG. 5 to provide an orifice effect. be able to. Furthermore, by changing the exhaust gas return distance l (Fig. 2) of the double pipe, it is possible to achieve a throttling effect (≈adjustment of the amount of silencing) according to the rotational speed.

Furthermore, when the length of the exhaust tail pipe is changed using the double pipes 9 and 10, the tone and volume of the muffler are slightly changed, and are adjusted according to the engine speed, temperature, etc.

The forward and backward adjustment of the double pipe described above may be performed manually, but for example, as shown in Fig. 6, the throttle valve 1
Amplifier 20 uses lever 18 and rod 19 to adjust the opening of 7.
The movement of the valve opening is mechanically or electrically amplified in the amplifier 20, and the rod 21 automatically adjusts the movement of the movable tubes 4 and 9 to advance and retreat. Alternatively, the flow rate or temperature of the exhaust gas may be detected by a sensor, and the above automatic adjustment may be performed by electromechanical means responsive to the sensor signal.

C. Effects of the invention Since the movable tube is guided out of the muffler body as a sliding double tube, and the length of the tube is changed by advancing it, the structure is simple and can be adjusted to the rotation of the engine. Matching noise countermeasures can be easily obtained.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is an illustrative view of the gas leak prevention mechanism, Fig. 3 is an isolated view of the configuration of Fig. 1, and Figs. 4 and 5 are movable tubes. FIG. 6 is a schematic diagram of an automatic adjustment mechanism. 4, 5, 9, 10... double tube, 15, 16...
A gas leak prevention mechanism for the end plates 14, 11 of the movable tubes 4, 9, 17...throttle valve.

Claims (1)

[Claims] 1. In a muffler for an internal combustion engine, which is divided into a plurality of muffling chambers using a partition plate and communicated with each chamber via a joint pipe, the joint pipe is made into a double pipe and an inner and outer pipe are used. An exhaust passage is formed between them, one of the pipes is fixed to a partition plate or an end plate of the muffler body, the other pipe is extended to the outside of the muffler body and movable, and the extended end is closed. A muffler for an internal combustion engine, characterized in that the total pipe length of the double pipe can be changed by moving the movable pipe in and out, and at the same time, the arrangement interval of the divided muffler chambers can be substantially changed. 2. The muffler for an internal combustion engine according to claim 1, wherein the movable pipe is manually moved in and out. 3. The muffler for an internal combustion engine according to claim 1, wherein the movable pipe is automatically moved in and out according to the rotational status of the internal combustion engine.