JPS5898621A - Exhaust gas purifying device of internal combustion engine - Google Patents

Abstract

PURPOSE:To suppress the lowering of the temperature of exhaust gas due to the introduction of cool secondary air by coating an assembled connecting pipe and a part of the outer periphery of a rear exhaust pipe, and communicating an opening of the secondary air supply pipe with the inside of an exhaust gas passage. CONSTITUTION:An exhaust pipe Ex comprises a plurality of front exhaust pipes 9 communicated and connected respectively to a plurality of exhaust ports 8, a single rear exhaust pipe 10 connected with an exhaust muffler and the assembled connecting pipe 11 communicated and connected with a plurality of exhaust pipes 9 and a single rear exhaust pipe 10. The assembled connecting pipe 11 and at least a part of the outer periphery of the rear exhaust pipe 10 are encircled by a heat-resisting, heat insulating material 12, and further the outer periphery of the heat insulating material 12 is coated with the outer cylinder 13 divided into two parts. The forward end of the outer cylinder 13 is welded and bonded to the rear ends of the two front exhaust pipes 9. The opening end part of the secondary air supply pipe 17 is communicated within the exhaust passage the temperature of which is maintained by the heat insulating material 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas purification device for an internal combustion engine for supplying secondary air for exhaust purification into an exhaust pipe connected to an exhaust boat of the internal combustion engine.

Conventionally, it is known that secondary air is supplied into the exhaust pipe of an internal combustion engine to promote the combustion of unburned components in the exhaust gas flowing there, but in such an engine, the temperature of the exhaust gas flowing inside the exhaust pipe is It is desirable to maintain the exhaust gas at a high temperature so that the exhaust gas temperature does not drop suddenly even when cold secondary air is introduced, and to evenly mix the secondary air and exhaust gas to promote the exhaust gas purification reaction ~1° SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide an exhaust gas purification device for an internal combustion engine with a simple structure, which achieves the above-mentioned object.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, an internal combustion engine E for running the motorcycle is mounted on a body frame F of the motorcycle, and an intake boat 5.5 is opened at the back of the cylinder head 3 of the engine body 1. 5 is connected to a capretor 6 and an air cleaner 7 extending behind the vehicle body frame F. Further, two exhaust boats 8.8 are opened at the front of the cylinder head 3 of the engine body 1, and an exhaust pipe Ex is connected to these exhaust ports 8.8.

Next, the specific structure of the exhaust pipe Ex will be explained. It is composed of two front exhaust pipes 9, 9, one rear exhaust pipe 10, and a collective connecting pipe 11 that connects them together. has been done. The two front exhaust pipes 9.9 are curved from the front to the side of the engine body 1, and their front open ends are connected to the exhaust port 8.8 of the engine body 1, and The rear open ends thereof are gathered together and welded to the front end of the collective connection pipe 11, and the rear exhaust pipe 10 is welded to the rear end of the collective connection pipe 11.At least of the collective connection pipe 11 and the rear exhaust pipe 10. A part of the outer periphery is surrounded by a heat-resistant heat insulating material 12, and the outer periphery of the heat insulating material 12 is further covered by an outer cylinder 13 divided into two parts, and the front end of this outer cylinder 13 is connected to two front exhaust pipes 9, The rear end of the rear exhaust pipe 9 is welded to the rear end of the rear exhaust pipe 10 . An exhaust muffler M is connected to the rear end of the rear exhaust pipe 10, and a catalytic converter is built in the exhaust muffler M as required. In addition, a protector 1 is provided on the outside of the front packing outer cylinder 13 so as to cover the outer half thereof.
4 is provided.

A mounting hole 15 is formed in the joint surface of the two-part outer cylinder 13, and an insertion hole 16 is formed in the rear exhaust pipe 10 corresponding to the mounting hole 15. A secondary air supply pipe 17 runs longitudinally on the outer cylinder 13, the open end of which is curved, passes through the mounting hole 15, is welded thereto in an airtight manner, and then passes through the heat insulating material 12. It passes through the insertion hole 16 and opens into the exhaust passage of the exhaust pipe Eχ. An annular gap C is formed between the open end of the secondary air supply pipe 17 and the insertion hole 16. In the middle of the secondary air supply pipe 17 is the outer cylinder 13.
The other end is connected via a flexible hose 21 to an outlet port 253 of an exhaust pulsating pressure valve, ie, a reed valve, which will be described later.

The engine body 1 is located near the exhaust valves 19 and 19 of the two exhaust ports 8 and 8 formed in the cylinder head 3 of the engine body 1.
The secondary air passages 23, 23 formed across the cylinder block 2 and the cylinder head 3 communicate with each other, and these passages 23, 23 are opened on the outer surface of the cylinder block 2, and the opening ends thereof are provided with: A secondary air supply pipe 18.18 is connected via the joint 24.24. The secondary air supply pipe 18.18 is connected via a flexible hose 22.22 to the two outlet bows of the exhaust pulsating pressure valve, i.e. the reed valve) 25. ．． 25. connected to. Further, the other outlet port 253 of the reed valve is communicated with the other secondary air supply pipe 17 which is communicated with the exhaust pipe Ex as described above.

One end of a secondary air supply main pipe 27 is communicated with the inlet boat 26 of the reed valve, and the main pipe 27 is communicated with the air cleaning chamber of the air cleaner 7 via an air control valve 28 on its way.

The reed valve valve is mounted on the crankcase 4 of the engine body 1 in a space surrounded by the cylinder block 2, exhaust pipe Ex, and air cleaner 7 of the engine body 1, and the air control valve 28 is of a conventionally known type. , the valve is controlled to be closed when the introduction of secondary air into the exhaust system is unnecessary.

Inside the valve chamber 30 of the reed valve are the three outlet boats 25t, 252 and 25. The reed valve bodies 31. ．． 31□ and 31° are provided, and their reed valve bodies 31. ．． 312.

313 is constructed by attaching a lead 34 for opening and closing the valve hole 32 onto a valve seat body 33 with the valve hole 32 open.

When exhaust pulsating pressure occurs in the exhaust system due to the operation of engine E,
This acts on the reed valve body 31. through the three secondary air supply pipes 18.18 and 1T. ．． 31
By opening the □ and 31° leads 34 intermittently, the secondary air from the secondary air supply main pipe 27 can be introduced into the exhaust boats 8, 8 and the exhaust pipe Ex.

Next, the operation of the embodiment of the present invention will be explained.

Now, due to the operation of the internal combustion engine E, the exhaust port of the exhaust system)8.
8 and the exhaust pulsating pressure generated in the exhaust pipe Ex is transmitted through the secondary air passage 23.23, the secondary air supply pipe 18.18 and the hose 22.22, or the secondary air passage 23.23. and the reed valve body 31 through the hose 21 and act on the reed valve valve 17.
．． ．． Each lead 34 of 31□ and 313 is opened intermittently,
The clean air inside the air cleaner 7 is supplied to the secondary air supply main pipe 27
Pass through and enter the reed valve, and from there exhaust boat 8,8
It is introduced into the rear exhaust pipe 10 of the exhaust pipe Ex to purify and remove unburned components in the exhaust system a.

As described above, according to the present invention, the exhaust pipe is connected to a plurality of front intake pipes connected to the exhaust port of the engine body, a rear exhaust pipe connected to the exhaust muffler, and a collective connecting pipe that communicates and connects them. At least part of the outer periphery of the collective connection pipe and the rear exhaust pipe is covered with a heat insulating material, and the open end of the secondary air supply pipe is communicated with the exhaust passage kept warm by the heat insulating material. Therefore, the exhaust gas flowing through the multiple front exhaust pipes is kept warm by the heat insulating material, and the concentrated flow in the exhaust passage whose capacity has been increased increases, and it not only mixes well with the secondary air introduced into the exhaust passage. The exhaust gas purification efficiency can be greatly improved by suppressing the temperature drop in the exhaust gas due to the introduction of cold secondary air.

[Brief explanation of drawings]

Fig. 1 is a side view of a motorcycle equipped with an internal combustion engine equipped with the bag device of the present invention, Fig. 2 is a vertical sectional side view of the main part of the internal combustion engine, Fig. 3 is a sectional view taken along the line ■-■ in Fig. 2, 4 is a sectional view taken along the line IV-IV in FIG. 2, FIG. 5 is a plan view of the exhaust pipe, FIG. 6 is a side view thereof, FIG. The figures are a sectional view taken along line VI-vnts in FIG. 6, and FIG. 9 is a sectional view taken along line IX-IX in FIG. α. E... Internal combustion engine, Ex... Exhaust pipe, M... Exhaust muffler, 1... Engine body, 8-' exhaust port, 9...
Front exhaust pipe, 10...Rear exhaust pipe, 12...Insulating material, 17...Secondary air supply pipe Patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] A plurality of front exhaust pipes (9, 9) each connected to a plurality of exhaust ports (8, 8) opened in the engine body (1) of the internal combustion engine (E), and an exhaust muffler l. ), and a collective connecting pipe (11) that communicates and connects the plurality of front exhaust pipes (9, 9) and the single rear exhaust pipe (10). and constitute an exhaust pipe (Ex), and at least part of the outer periphery of the collective connection pipe (11) and the rear exhaust pipe (10) is covered with a heat insulating material (12),
An exhaust purification device for an internal combustion engine, in which the open end of a secondary air supply pipe (17) is communicated with the exhaust passage kept warm by the heat insulating material (12).