JPS6033295Y2 - Exhaust gas purification device for multi-cylinder internal combustion engines - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The invention supplies secondary air to each exhaust port of a multi-cylinder internal combustion engine to effectively oxidize and eliminate unburned harmful components in the exhaust gas. The present invention relates to an exhaust gas purification device for a multi-cylinder internal combustion engine.

(2) Conventional technology A multi-cylinder internal combustion engine, in particular, the multiple cylinders formed in the engine body are arranged separately into two left and right groups, and the exhaust ports communicating with each cylinder are arranged in parallel on the same side of the engine body. In this type of internal combustion engine, a reed valve device is installed independently in the secondary air supply path connected to each exhaust port, and these reed valve devices are opened by exhaust pulsating pressure during engine operation, and each exhaust port A device in which secondary air is introduced is conventionally known.

(3) Problems to be solved by the invention In the conventional system, the secondary air distribution passage branched from the secondary air introduction pipe that opens to the atmosphere is routed through a plurality of parallel cylinders in a complicated manner. Since the secondary air distribution passages are connected to the respective reed valves, the lengths of the secondary air distribution passages are significantly unequal, and the passages themselves are long, so that it is difficult to uniformly distribute a sufficient flow rate of secondary air to each exhaust port. It is difficult to provide a stable supply.

An object of the present invention is to provide an exhaust gas purification device for a multi-cylinder internal combustion engine that can eliminate such problems.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above-mentioned object, the present invention separates and arranges a plurality of cylinders formed in the engine body into two groups, left and right, and each cylinder In an in-line multi-cylinder internal combustion engine, in which exhaust ports that communicate with each other are arranged in parallel on the same side of the engine body, each of the two left and right groups is provided on the cylinder rad cover that is attached to the cylinder head of the engine body. Two groups of left and right reed valve devices for independently supplying secondary air to the cylinders are arranged in parallel, and a pair of left and right first reed valve devices are arranged in parallel along one side of the two groups of left and right reed valve devices. A second secondary air distribution passageway is provided and the first. A second secondary air distribution passageway is connected to the second secondary air distribution passageway, respectively. Each of the independent upstream chambers of the second group of reed valve devices is communicated with each other through a secondary air inlet having a passage cross-sectional area smaller than that of the secondary air distribution passage, and each of the independent upstream chambers of the reed valve devices of the second group The chambers are in communication with their respective exhaust ports, and the first chamber is connected to the exhaust port corresponding to the chamber. The second secondary air distribution passage is characterized in that it gathers at the left and right center portions of the engine body and communicates with one secondary air introduction pipe that opens to the atmosphere.

(2) Two secondary air distribution passages that branch left and right at the center of the engine body from one secondary air introduction pipe that opens to the working atmosphere,
Since it is arranged along one side of the two groups of left and right reed valve devices arranged in parallel on the rad cover to the cylinder, the secondary air distribution passage is connected to each exhaust port parallel to the engine body. The distances between the secondary air passages can be made substantially equal to each other, and the flow resistance of the secondary air flowing through them can be made substantially equal.

Moreover, since each of the secondary air distribution passages can be formed linearly along each arrangement direction of the cylinders and reed valve devices, the distribution passage itself can be made thick and short without interfering with each cylinder, and each lead The distance to the valve device can also be shortened to reduce the flow resistance of secondary air flowing through them.

Furthermore, the secondary air passages from each secondary air inlet having a relatively small passage cross-sectional area branched from each secondary air distribution passage, through each upper and downstream chamber of the reed valve device, to each exhaust port are completely independent from each other. Therefore, the reed valve devices separately installed in these air passages can be accurately opened and closed without interfering with each other at all.

(3) Example Hereinafter, an example in which the present invention is applied to an in-line 6-cylinder internal combustion engine for a motorcycle will be explained with reference to the drawings. In FIG. is supported, and front and rear wheels Wf and Wγ are supported in front and behind it, and in the space surrounded by these, an in-line six-cylinder internal combustion engine E for driving the rear wheel Wγ is mounted on the body frame F. has been done.

In FIGS. 2 and 3, a cylinder block 1 of the engine body of an in-line six-cylinder internal combustion engine includes a plurality of cylinders C1, C2, C3, and C4, C5, C6, which are separated into two groups, and a central camshaft transmission section. They are arranged in series with the two sides in between.

A piston 3 is slidably fitted into each cylinder.

A cylinder head 2 is superimposed and fixed on the cylinder block 1 , and a combustion chamber 4 is formed in the cylinder head 2 above each piston 3 .

Intake ports 5 communicating with each combustion chamber 4 are arranged on the rear side of the cylinder head 2, and the cylinder head 2
Exhaust ports 6 communicating with each combustion chamber 4 are arranged on the front side of the engine.

Each of the intake ports 5 opens to the rear surface of the internal combustion engine E, and each exhaust port 6 opens to the front surface of the internal combustion engine E.

An intake system such as a carburetor 7 and an air cleaner 8 disposed at the rear of the internal combustion engine E is connected to the intake port 5, and an exhaust system such as an exhaust pipe 9 and a muffler 10 is connected to the exhaust port 6. An exhaust gas purifying catalytic converter 11 is interposed in the middle of the exhaust gas.

In addition, the cylinder head 2 has intake and exhaust valves 1 which open and close the open ends of the combustion chamber 4 side of the intake and exhaust ports 5 and 6 as usual.
2.13 are provided, which include the valve spring 14 and the valve drive cam 1.
It is opened and closed by cooperation with the rotation of 5.

Although not shown, the central camshaft transmission portion D of the main body of the internal combustion engine E accommodates a chain transmission mechanism that interlocks the crankshaft and the valve drive cam 15.

A heat insulating elastic packing material 1 is provided on the upper part of the cylinder head 2.
A rad cover 17 is attached to the cylinder via 6.

The cylinder rad cover 17 has cylinders C□, C2, C3 and "tt C5!" of the two left and right groups on the left and right upper surfaces thereof.
Corresponding to C6, two groups of left and right exhaust pulsation reaction type reed valve devices L□, L2. L3. and L4. L=,, L8
are arranged in parallel, and these reed valve devices L1. L2.
L3 and Tori.

The cylinders C1, C2, C3 and C4 of Lis, Le
, C6, and the relative positions with respect to C6 are approximately the same.

The reed valve devices I, I, L and Rui.

Since L, ,, L all have the same structure, one of them L
1, the specific structure thereof will be explained with reference to FIG. 3. The valve surface 18 of the reed valve device includes a valve surface portion 181 integrally formed on the upper surface of the rad cover 17 to the cylinder,
On top of this, a plurality of mounting bolts 20 are inserted through the packing 19.
The reed valve chamber A is formed inside the cover integrally 18□, which is fixed to the cover 18□.

In the reed valve chamber A, a reed valve 23 is fixed onto the valve surface portion 18□ with a set screw 24 via a heat-resistant elastic packing material 21 and a mounting plate 22.
3, the reed valve chamber A has an upstream chamber a1 and a downstream chamber a2.
The upstream chamber a□ and the downstream chamber a2 communicate with each other through a valve port 25 opened to the reed valve 23.

The reed valve 23 has a reed 26 that can open and close the valve port 25 on the lower surface facing the downstream chamber a2, and a reed 26 for opening and closing the valve port 25.
A lead stopper 27 that limits the opening degree of the lead stopper 27 is overlapped and fixed by a set screw 28.

As clearly shown in FIG.
And on the left and right front side of the cover, extending 18 degrees, there are two groups of cylinders, C2, C3 and C4 = C5y.
Secondary air distribution passages 30, 31 are formed along C6, and one secondary air distribution passage 30 is connected to reed valve devices L□, L2. Through a secondary air inlet 32 formed integrally with the cover of L3 at an angle of 18 degrees and having a smaller passage cross-sectional area than the passage 30, it is communicated with each of the independent upstream chambers a1, and the other secondary air distribution passage 31 is also communicated. , reed valve device mounting t t's, is connected to each of these independent upstream chambers a□ through a secondary air inlet 32 formed in the cover 18□ of L3 and having a passage cross-sectional area smaller than that of the passage 31. .

The two left and right secondary air distribution passages 30, 31 are both formed to have a large diameter (approximately 2-diameter) so as to reduce passage resistance, and are also formed to have the same diameter over their entire length.

In addition, the upstream ends of the two secondary air distribution passages 30, 31, that is, the ends located near the central camshaft transmission section, are gathered together and connected to one secondary air introduction pipe 34 via the connecting pipe 33. The secondary air introduction pipe 34 is connected to the air cleaning chamber of the air cleaner 8 through an air control valve (2) in the middle thereof.

The air control valve V is conventionally known and is opened and closed in response to intake negative pressure within the intake system when the internal combustion engine E is operating.

The downstream chamber a2 of the reed valve device pile ~L6 includes a secondary air passage 35 formed in the rad cover 17 and another secondary air passage 36 formed in the cylinder head 2, respectively.
The exhaust port 6 is connected to the exhaust port 6 through the exhaust port 6.

The secondary air passages 35 and 36 are connected to each other via a connecting joint J, which will be described later, when the cylinder head 2 and the head cover 17 are coupled.

The connection joint J is constructed by applying a heat-resistant and acid-resistant coating 40 such as a dacro coating to the entire surface of a hollow cylindrical connection body 39 made of iron, with the upper half having a small diameter and the lower half having a large diameter. formed into a diameter.

The lower half of the large diameter of the connection joint J is connected to the cylinder head 2.
The upper half of the small diameter of the connection joint J is airtightly fitted into the open end of the secondary air passage 36 on the head cover 17 side via an O-ring 37.
6 through an O-ring 38 in an airtight manner.

9. The connecting joint J also serves as a guide member when assembling the head cover 17 to the cylinder head 2.

Next, the operation of one embodiment of the present invention constructed as described above will be explained.

When the internal combustion engine is now operated, exhaust pulsating pressure is generated in each exhaust port 6, and this pulsating pressure is transmitted to the secondary air passage 36, 35.
When the air control valve V is opened by the operation of the engine E, a part of the clean air in the air cleaner 8 passes through the secondary air introduction pipe 34 to the two reed valves 23 and opens the reed valves 23. It is divided into the main secondary air distribution passages 30, 31 and guided to the upstream chamber a□ in each valve face 18, and further flows into the downstream chamber through the valve port 25 of each reed valve 23, from where the secondary air Air is introduced into each exhaust port 6 through passages 35,36.

The secondary air introduced into the exhaust port 6 mixes into the exhaust gas, and oxidizes unburned harmful components such as HC and CO mixed in the exhaust gas in the exhaust port 6 and the exhaust pipe 9.

Furthermore, the exhaust gas mixed with secondary air flows into the muffler 10, promotes the reaction of the catalytic converter 11 built therein, and finally purifies the unburned harmful components therein before being released into the atmosphere.

Effects of the C design As described above, according to the present invention, the plurality of cylinders C□ to C6 formed in the engine body are arranged separately into two left and right groups, and the exhaust port is connected to each cylinder C□ to C6. 6 are arranged in parallel on the same side of the engine body, each cylinder of the two left and right groups is placed on the cylinder cover 1 cover attached to the cylinder head 2 of the engine body. C0 to C3; two groups of left and right reed valve devices L1 to L3 for independently supplying secondary air to C2 to C6;
L, ~L6 are arranged in parallel, and two groups of left and right reed valve devices are installed ~Ls; Second secondary air distribution passage 30,3
1, and those 1st. Second secondary air distribution passage 30.
31 respectively to said first . 2nd group glued valve device L□
~L3; communicates with each independent upstream chamber a0 of L4 to L6 via a secondary air inlet 32 having a passage cross-sectional area smaller than that of the secondary air distribution passage 30.31, and also communicates with L1 of those reed valve devices. ~L3; L4~Fuku's independent downstream chambers a2
are communicated with the corresponding exhaust ports 6, and the first. The second secondary air distribution passages 30 and 31 gather at the left and right center portions of the engine body and open to the atmosphere.
Since it communicates with the main secondary air introduction pipe 34, the secondary air distribution passage 3 disposed along one side of the left and right two groups of reed valve devices L1 to L on the cylinder head cover 17;
0.31 means that the distances of the secondary air passages from the secondary air distribution passage 30.31 to the exhaust ports 6 parallel to the engine main body side can be made approximately equal to each other, and the secondary air flowing through them can be made approximately equal. The air flow resistance can be made approximately equal, and each secondary air distribution passage 30, 31 can be formed linearly along the arrangement direction of the cylinders C1 to C6 and the reed valve devices L1 to L6. The air distribution passage 30.31 itself can be formed thick and short without interfering with each cylinder C1 to C6 or reed valve device L□ to L6, and each reed valve device I
, -1, can be shortened to reduce the flow resistance of the secondary air flowing through them, and each branched from each secondary air distribution passage 30, 31 has a relatively small passage cross-sectional area. From the secondary air inlet 32 to the reed valve device ~L
6, each upper and downstream chamber a1. The secondary air passages leading to each exhaust port 6 via a2 can be made completely independent from each other,
Reed valve devices L□~ installed separately in those air passages
L6 can be opened and closed accurately without any interference with each other, and as a result of the above, it is possible to uniformly and stably supply a necessary and sufficient amount of secondary air to each exhaust port 6 as a whole, especially to the cylinders. This effect becomes more noticeable in internal combustion engines, which are used in large numbers.

[Brief explanation of the drawing]

Fig. 1 is a side view of a motorcycle equipped with a multi-cylinder internal combustion engine equipped with the device of the present invention, Fig. 2 is a partially cutaway plan view thereof, and Fig. 3 is a vertical sectional side view taken along the line ■-■ in Fig. 2. . C1, C2? C3, C4, C5, Ce-...
Cylinder, L□. Lz, L3t Let I/, t t,...
Reed valve device, a-work...upstream chamber, a2...
...Downstream chamber, 2...Cylinder head, 6...
...Exhaust port, 17...Rad cover to cylinder, 30...Secondary air distribution passage, 31...
...Secondary air distribution passage, 32...Secondary air introduction port, 34...Secondary air introduction pipe.

Claims (1)

[Scope of utility model registration request] A series type engine in which a plurality of cylinders C1 to C6 formed in the engine body are arranged separately into two left and right groups, and exhaust ports 6 communicating with each cylinder C to C6 are arranged in parallel on the same side of the engine body. In a multi-cylinder internal combustion engine, on the cylinder cover 1 which is attached to the cylinder head 2 of the engine main body, two cylinders are provided independently for each of the cylinders C□ to C3; C, to C6 of the two left and right groups. Next, two groups of left and right reed valve devices for supplying air Lt-La; L4 ~ arrange rice in parallel, and reed valve devices for these two groups of left and right ~ L3; L4 ~ 1.
A pair of left and right first . A second secondary air distribution passage 30,31 is provided, and a second secondary air distribution passage 30,31 is provided. A second secondary air distribution passage 30, 31 is connected to each independent upstream chamber a□ of the reed valve devices L1 to L3; L4 to L6 of the first and second groups from the secondary air distribution passage 30, 31, respectively. It also communicates through the secondary air inlet 32 with a small passage cross-sectional area, and also communicates each independent downstream chamber a2 of the reed valve device ~L3; L4~L6 with the corresponding exhaust port 6. Furthermore, the above-mentioned No. 1. The second secondary air distribution passages 30, 31 are assembled at the left and right center of the engine body,
An exhaust gas purification device for a multi-cylinder internal combustion engine, which communicates with one secondary air introduction pipe 34 that opens to the atmosphere.