JPH10115215A - Catalyst exhausting system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst exhausting system for an internal combustion engine which can improve silencing effect while reducing exhaust resistance of a muffler and improve exhaust emission control efficiency while making exhaust gas flow through an entire catalyst. SOLUTION: A muffler 10 is connected to an exhaust pipe of an engine. An inlet pipe 15 and an outlet pipe 33 are arranged in the muffler 10. The inner space is divided into a resonance chamber 16, a catalyst housing chamber 17 provided with an exhaust emission controlling catalyst, and a muffle chamber 18 sequentially from an upstream side of exhaust, by means of plurality of partition walls 19a, 19b. The partition wall 19a of the resonance chamber 16 lead to the catalyst housing chamber 17 is conically formed for connecting the inlet pipe 15 to a small diameter portion 20. The catalyst housing chamber 17 is connected to a large diameter portion 23 of the partition wall 19a. Small holes 22 are properly formed on a tapered portion 21 of the partition wall 19a. An introduction pipe 29 of the muffler chamber 18 is arranged around an outlet pipe 33, in the vicinity of an outer periphery and on a downstream side of the catalyst housing chamber 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic exhaust system for an internal combustion engine, for example.

[0002]

2. Description of the Related Art Conventionally, mounting a catalyst on a muffler has been widely adopted as an exhaust purification measure. However, in order to muffle sound by this muffler and purify the exhaust gas by the catalyst, exhaust gas must be supplied to the entire catalyst. It is required to pass.

FIG. 2 shows a conventional catalytic exhaust system of an internal combustion engine. In this catalytic exhaust system, exhaust gas introduced from an exhaust pipe of the engine enters an muffler 2 through an inlet pipe 1 and a part of the exhaust gas is introduced. The exhaust gas flows into the catalyst 4 from the outlet 3 of the inlet pipe 1 as it is, and the other exhaust gas enters the expansion chamber 6 through the small hole 5 provided in the inlet pipe 1 and passes through the outlet 8 of the isolation wall 7. To catalyst 4. The exhaust gas purified by the catalyst 4 is
The gas enters the expansion chamber 11 through the small hole 10 on the upstream side of the outlet pipe 9, and is discharged from the outlet 13 of the outlet pipe 9 through the small hole 12 on the downstream side of the outlet pipe 9.

[0004]

However, in the catalytic exhaust system for an internal combustion engine having the above-described structure, the flow path is complicated because exhaust gas flows through the entire catalyst, and the exhaust resistance increases. The engine output may decrease.
From this fact, it is conceivable to increase the size of the muffler to increase the size of the catalyst and reduce the exhaust resistance. However, such a method requires a large amount of an expensive catalyst and increases the cost.

The present invention solves the above problems,
An object of the present invention is to provide a catalytic exhaust device for an internal combustion engine that can reduce exhaust resistance of a muffler, increase a noise reduction effect, and improve exhaust gas purification efficiency by allowing exhaust gas to flow through the entire catalyst. Is to do.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a muffler connected to an exhaust pipe of an engine, an inlet pipe and an outlet pipe provided in the muffler, and the inside of the exhaust pipe is provided with a plurality of partition walls. In order from the side, a resonance chamber, a catalyst accommodating chamber in which a catalyst for purifying exhaust gas is mounted, and a muffling chamber are partitioned, and the isolation wall of the resonance chamber that reaches the catalyst accommodating chamber has a substantially conical shape, and an inlet pipe is connected to a small diameter portion. The catalyst accommodating chamber is provided by connecting to the large diameter portion of the isolation wall, a small hole is appropriately provided in the inclined portion of the isolation wall, and the introduction pipe of the muffling chamber is provided near the outer periphery on the downstream side of the catalyst accommodating chamber. The outlet pipe is arranged at the periphery and at the center.

According to the catalytic exhaust system for an internal combustion engine having the above structure, the exhaust gas introduced into the muffler from the exhaust pipe of the engine via the inlet pipe flows through the conical isolation wall, so that the exhaust resistance is reduced. Moreover, the exhaust gas spreads in the conical shape and flows toward the entire catalyst. In addition, since the inlet pipe of the silencing chamber is disposed around the outer periphery of the downstream side of the catalyst accommodating chamber, the exhaust gas is easily guided to the outer peripheral surface of the catalyst. Efficiency can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an assembled sectional view of a catalytic exhaust system for an internal combustion engine according to the present invention. In the figure, a muffler 12 connected to an exhaust pipe of an engine (not shown) has a cylindrical casing 11 having both ends closed by disks 12 and 13, and the disk 12 is provided with an inlet pipe 11 having a flange 10. The interior of the casing 11 is partitioned into three chambers, a resonance chamber 16, a catalyst storage chamber 17, and a silencing chamber 18, in this order from the upstream side.
The resonance chamber 16, the catalyst storage chamber 17, and the silencing chamber 18
Are formed by partitions 19a and 19b. The partition wall 19a in the resonance chamber 16 reaching the catalyst storage chamber 17 has a conical shape, and the small diameter portion 20 of the partition wall 19a is
The inclined portion 21 is provided with a small hole 22 as appropriate.

In the above-mentioned catalyst accommodating chamber 17, catalyst holders 24 and 25 are attached to the casing 11 at the front and rear.
The catalyst 27 is held via the cushion material 26.

A partition wall 19b is attached to the casing 11 downstream of the catalyst accommodating chamber 17, and three to five inlet pipes 29 having small holes 28 of the muffling chamber 18 are provided around the inner periphery of the casing 11 of the partition wall 19b. And is supported by a support plate 30 at the rear of the introduction tube 29. An outlet pipe 33 having an inflow port 31 and a sound absorbing port 32 is provided at the center of the introduction pipe 29 so that the disc 13 of the casing 11 is provided.
The sound absorbing member 34 is provided around the sound absorbing opening 36 and is held by a holding tube 35 on the outer periphery thereof.

In the catalytic exhaust system configured as described above, the exhaust gas introduced from the inlet pipe 15 is supplied to the resonance chamber 16.
The sound is muffled between the small hole 22 provided in the inclined portion 21 of the partition wall 19a and spreads in the conical partition wall 19a, flows without receiving resistance, and reaches almost the entire surface of the catalyst 27, but in the partition wall 19a. Although a large amount of exhaust gas still flows near the center, the silencing chamber 18 on the outlet side of the catalyst 27
Is disposed near the outer peripheral surface, the exhaust gas can be guided in the outer peripheral direction and can flow uniformly over the entire surface of the catalyst 27, and the flow in the silencing chamber 18 forms a simple flow. As a result, an increase in resistance can be prevented, and a noise reduction effect can be obtained by expansion and sound absorption.

[0012]

As described in detail in the above embodiment, in the catalytic exhaust system for an internal combustion engine according to the present invention, the exhaust gas introduced from the inlet pipe is silenced by the small hole in the inclined portion of the partition wall in the resonance chamber. The exhaust gas spreads through the conical partition wall and flows without resistance, reaches almost the entire surface of the catalyst, and the exhaust gas is guided in the outer peripheral direction to the introduction pipe near the outer peripheral surface of the silencing chamber on the outlet side of the catalyst. As a result, purification efficiency can be improved, and the flow in the silencing chamber forms a simple flow, which has the effect of preventing an increase in resistance.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing a catalytic exhaust device for an internal combustion engine according to the present invention.

FIG. 2 is an overall sectional view showing a conventional catalytic exhaust device of an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Casing 15 Inlet pipe 16 Resonance room 18 Silence room 19a Partition wall 29 Introducing pipe

Claims (1)

[Claims] 1. A muffler is connected to an exhaust pipe of an engine,
The muffler is provided with an inlet pipe and an outlet pipe, and the inside is partitioned into a resonance chamber, a catalyst housing chamber in which a catalyst for exhaust gas purification is mounted, and a silencing chamber in order from the exhaust upstream side by a plurality of partitions, and reaches the catalyst housing chamber. The isolation wall of the resonance chamber is formed in a substantially conical shape, the inlet pipe is connected to the small diameter portion, and the catalyst storage chamber is connected to the large diameter portion of the isolation wall, and the small hole is appropriately provided in the inclined portion of the isolation wall. A catalytic exhaust device for an internal combustion engine, wherein an introduction pipe of the muffling chamber is arranged around an outer periphery of a downstream side of the catalyst accommodating chamber, and the outlet pipe is arranged at the center.