JPS5848747B2 - Torch ignition engine exhaust purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the combustion chamber is composed of a main chamber above the piston, and a sub-chamber that communicates with the main chamber through a torch nozzle and has an ignition plug inside. It includes a sub-intake passage that supplies a rich air-fuel mixture and a main intake passage that supplies a lean air-fuel mixture from the main carburetor to the main chamber, and heats the bottom of the main sub-intake passage branch pipe collection section by heat released from the engine. The present invention relates to an exhaust purification device for a torch ignition engine that naturally purifies unburned gas in an exhaust path.

In a torch ignition engine, the air-fuel ratio is made leaner than the theoretical air-fuel ratio, and the air-fuel mixture is combusted as completely and stably as possible in the main chamber, and the unburned gas generated is ejected into the exhaust passage before being released to the atmosphere. It is desired that the dehog be completely purified by self-combustion.

On the other hand, since the rich air-fuel mixture is supplied to the pre-chamber, this is sufficiently promoted to vaporize.At the same time, when the engine is compressed, the lean air-fuel mixture in the main chamber flows back into the sub-chamber, so this lean mixture is also sufficiently vaporized and stabilized. It is desired to obtain a torch that is

However, in conventional torch ignition engines, each cylinder is provided with an independent exhaust passage, and the heat insulation device for the exhaust passage is only partially implemented, and the insulation means is a branch pipe. Emphasis was placed on the gathering area.

Therefore, the unburned gas discharged from the exhaust port is cooled down before reaching the exhaust path branch pipe collection section, and is not able to fully combust within the branch pipe collection section and is released into the atmosphere, causing air pollution even though it is a torch-ignited engine. There was a drawback.

The present invention solves the above problems and maintains the temperature of the entire exhaust passage from the main chamber exhaust port to the branch pipe collection part as high as possible, thereby providing a torch ignition engine that satisfies the above-mentioned requirements. To provide an exhaust purification device for a torch ignition engine that is simple, highly productive and durable, and can reduce weight.

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

In Fig. 1, 1 is the first cylinder, 2 is the lth cylinder 1
3 is the exhaust port of the second cylinder, 4 is the exhaust port of the second cylinder, and the exhaust ports 2 and 4 are arranged adjacent to each other.

The exhaust ports 6 and 8 of the third and fourth cylinders 5 and 7 are also adjacent to each other and are symmetrical with the first and second cylinders 1 and 3.

Therefore, the description will focus on the first and second cylinders.

High-temperature exhaust gas discharged from the exhaust ports 2 and 4 of the main chamber merges immediately after the exhaust ports 2 and 4, becomes a single stream, and flows through the exhaust path 9.

This exhaust path 9 has a space layer io on each back side as shown in FIG.
.

This is because the exhaust passage 9 has curved parts and a complicated shape, so the inner cylinder 12 cannot be inserted into the exhaust passage 9, and casting is the best way to keep the entire exhaust passage 9 sufficiently warm.

In order to support the inner cylinder 12, the exhaust inlet of the inner cylinder 12 is provided with an end 14 that abuts or is embedded in the outer wall 15, and the outer wall 15 of the exhaust passage 9 is further provided with a convex portion 16. .

A space layer 11 is provided on the back surface of the inner cylinder 12.
1 is formed by removing casting sand.

As a result, the contact area between the cylinder head 13 and the inner cylinder 12 can be minimized, and the exhaust temperature can be further improved.

In addition, the inner part label 12' and the outer member 12'/ of the inner cylinder 12 are fixed to each other at the valve guide hole part 18 and the open end 19, and the casting sand is applied to the member 1.
This prevents it from entering 2' and 1r.

Note that the convex portion may be provided on the inner cylinder 12 side. Also, in FIG. 2, the outer inner cylinder 1 of the inner cylinder 12? A space layer 11 is provided between the outer wall 15 and the outer wall 15, but as shown in FIG.
It may be cast so that the two holes are in contact.

In this case as well, the valve guide hole 18 and the opening end 19 of the inner cylinder 12
The molding sand is fixed to prevent it from entering the inner and outer cylinders 12', 12'%'i.

This is to increase the strength of the throat inner cylinder 12, which prevents the casting sand from vibrating due to engine vibrations and producing abnormal noises, or from entering the combustion chamber and damaging piston rings, cylinders, etc.

Note that 17 indicates a main chamber, and 17' indicates a sub-chamber.

In this way, in the present invention, the exhaust ports are adjacent to each other, and the exhaust paths are merged into a single exhaust path immediately after the exhaust ports, so that the frequency of exhaust gas passing through the exhaust path can be reduced compared to the exhaust path provided independently for each cylinder. This makes it possible to maintain the exhaust path, which used to be prone to cold, at a constant high temperature, and the surface area of the exhaust path can be reduced to about 20% compared to an exhaust path provided independently for each cylinder, reducing the exhaust path temperature. can be made even higher.

In addition to this structure, at least a double inner cylinder made of metal with poor thermal conductivity such as stainless steel with a space layer interposed in the exhaust passage is provided, so that the exhaust from the exhaust port of the main chamber is kept almost cool. Even within this exhaust path, the self-combustion effect of unburned gas can be greatly improved.

Next, the high-temperature exhaust gas in the exhaust passage 9 of the cylinder head 13 flows to the branch pipe collection part 22 via the branch pipe part 21 of the exhaust passage 20 corresponding to the exhaust passage 9, as shown in FIG.

The branch pipes 21 and the branch pipe gathering section 22 are provided with at least a double metal inner cylinder 23 having a space layer on each back surface and having poor thermal conductivity such as stainless steel, and these are housed in an outer wall 24 made of cast iron. .

The inner cylinder 23 and the outer wall 24 are divided into two parts so that it is easy to manufacture products with complicated shapes.
3" and the outer wall 24.

The inner and outer cylinders 23', 23'' are connected to the upper members 25', 25''.
and lower members 26' and 26'', and these upper and lower members are fixed to each other to form an exhaust passage.

The outer wall 24 of the exhaust passage 20 is joined to the intake passage side via a gasket 27, and the upper and lower outer walls 24', 27t'' are connected with bolts 2.
It is formed by binding with 8.

The inner tubes 23' and 23'' are fixed to each other along the circumference near the open end 29 of the branch pipe 21, but a space layer 30 is interposed between the inner tubes 23' and 2γ in the outer branch pipe portion 21. .

A space layer 31 is also interposed between the outer wall 24 of the outer inner cylinder 23'h.

In this way, the branch pipe 21 forms a triple structure with the inner tubes 23', 23'' and the outer wall 24, so the heat retention effect can be further improved.
Unburnt gas can self-combust even while passing through this branch pipe section 21.

Furthermore, the high-temperature exhaust gas is guided to the branch pipe collecting portion 22 whose passage cross-sectional area gradually increases while being kept warm, and is discharged from the inner inner cylinder 23' having an opening 32 on the upper surface into the outer inner cylinder 23''.

This exhaust gas hits the outer inner cylinder 23f and flows in the direction of the arrow in FIG. 5, that is, in the counterclockwise direction.

Also, some exhaust gas flows as shown by the broken line.

In the branch pipe collection part 22, the inner and outer cylinders 23' and 23r are relatively widely separated, so the exhaust flow velocity can be slowed down, and the opening of the inner cylinder 2r is relatively far away in the opposite direction to the discharge port 33. 32, the residence time of the exhaust gas inside the branch pipe collecting section 22 can be lengthened, and the self-combustion effect of unburned gas can be greatly improved.

On the other hand, the upper surface of the outer inner cylinder 2" is provided relatively close to the bottoms 37 and 38 of the intake passage, and the upper outer wall 24 of the exhaust passage 20 constitutes the subchamber bottom 38, so that the heat of the entire outer wall 24 is not wasted. The bottom portions 37 and 38 can be formed with a large heat capacity.

The upper sub-intake passages 34 and 35 are led out from the branch pipe gathering part at the front and rear of the engine as shown in Fig. 17
The distances to the pre-chambers 17' of the odd-numbered cylinders and the pre-chambers 17' of the even-numbered cylinders are approximately equal.
Since the branch communication, so-called main and sub-intake passages 34 and 35, are arranged in a tournament shape so that the distances to the main and sub-intake passages 34 and 35 are approximately equal in length, the main and sub-air mixtures can be easily and uniformly distributed.

Moreover, since the main and sub-intake passages 34 and 35 are branched outside the cylinder head 13, where the bending radius can be made gentle, a more uniform air-fuel mixture can be easily supplied to each cylinder, and combustion variations between cylinders can be reduced.

Further, when heating the air-fuel mixture strongly, the upper surface of the upper inner cylinder 25'' of the outer inner cylinder 23'' may be opened.

With this configuration, the rich mixture in the sub-intake passage 35 and the lean mixture in the main intake passage 34 can be sufficiently vaporized by the heat released from the engine, and a stable torch can be obtained.

In addition, the inner and outer cylinders 23', 2γ are fixed to each other by lower members 26', 2σ', and these are further attached to the lower outer wall 24'' by bolts 3.
9 and nuts 40 in a self-supporting manner.

Since the inner cylinders 23' and 23'' are self-supporting in this way, they are supported near the center of gravity and have a stable posture, which has the advantage of excellent durability.

In this way, the present invention arranges the exhaust ports of odd-numbered cylinders and the exhaust ports of even-numbered cylinders adjacent to each other, unifies the exhaust path downstream of the exhaust port, and uses stainless steel with an air layer interposed in this exhaust path. At least two inner tubes with poor heat conductivity such as stainless steel are cast, and the branch pipe section and branch pipe collection section corresponding to this exhaust path are made of at least two inner tubes with poor heat conduction such as stainless steel having a space layer on the outer wall and outer back surface. Since it is constructed with a heavy inner cylinder, the temperature of the entire exhaust path from the exhaust port of the main chamber to the branch pipe gathering part can be maintained at a very high temperature.

Further improvement of the heat retention effect can be achieved by making the inner cylinders triple or quadruple.

It goes without saying that the present invention can also be applied to a cross-shaped engine.

As described above, according to the present invention, the engine overall air-fuel ratio is made leaner than the theoretical air-fuel ratio, the air-fuel mixture is combusted as completely and stably as possible in the main chamber, and the unburned gas generated can maintain the temperature of the entire exhaust passage. This is effective in keeping the exhaust gas as high as possible for self-combustion purification, thereby completely disposing of harmful components in the exhaust passage.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention, in which Fig. 1 is a plan view of the cylinder head, Figs. 2 and 3 are cross-sectional views of the exhaust passage (A-A cross section in Fig. 1), and Fig. 4 is a plan view of the cylinder head. FIG. 5 is a partial cross-sectional view of the exhaust passage taken along the line CC in FIG. 1, and FIG. 1...First cylinder, 2...First cylinder exhaust port, 3.゜゛...Second cylinder, 4゜゜゜.゛Second cylinder exhaust port, 5... ...Third cylinder, 6...Third cylinder exhaust port, 7...
...4th cylinder, 8...4th cylinder exhaust port, 9...exhaust path, 10, 11...
Spatial layer, 12...Double inner cylinder, 13...
Cylinder head, 14... end, 15...
...Outer wall, 16...Protrusion, 18...Valve guide hole, 17...Main chamber, 17'...Sub-chamber, 19... , open end, 20...exhaust path, 2
1...Exhaust path branch pipe section, 22...-Exhaust path gathering section, 23...Double inner cylinder, 24...
Outer wall, 25, 25'... Upper member, 26', l'
...lower member, 27... gasket soto, 2
8... Bolt, 29... Open end, 30
, 31... Spatial layer, 32... Opening,
33...Exhaust port, 34...Main intake path,
35...Sub-intake passage, 36...Collecting part (branch pipe), 37, 38...Bottom, 39...
...Bolt, 40...Nut.

Claims (1)

[Claims] 1. A sub-intake passage that supplies a rich air-fuel mixture from the sub-vaporizer to the auxiliary chamber, and a main intake passage that supplies a lean air-fuel mixture from the main carburetor to the main chamber; In a torch ignition engine, the bottom of which is heated by the heat released from the engine,
The exhaust ports of the odd-numbered cylinders and the exhaust ports of the even-numbered cylinders are arranged adjacent to each other, and one exhaust path is formed downstream of these exhaust ports.
A torch ignition engine characterized in that the exhaust passage is formed by casting a double inner cylinder with a space layer interposed therebetween, and the valve guide hole and opening end of the inner and outer cylinders are fixed to each other. Exhaust purification device.