JPS6336014A - Purifier for exhaust from marine propeller - Google Patents

Abstract

PURPOSE:To prevent an engine body from an adverse effect due to catalyzer heat by forming a sub-exhaust path for discharging exhaust to the atmosphere and a main exhaust path for discharging exhaust in the water respectively from separate members to house the catalyzer in the sub-exchaust path. CONSTITUTION:In an outboard engine mounting a 2-cycle 2-cylinder engine 16, the leading end of a main exhaust path 38 is formed to communicate directly to an exhaust port 33 of each cylinder. This main exhaust path 38 has one side surface defined by an inner cover 40 of engine 16 to communicate to an exhaust pipe 20. While an outer cover 44 is attached to the outside of inner cover 40, a portion of the inner cover 40 projects to the outside beyond the outer cover 44 to provide a branch port 46. And this branch port 46 is a leading end of a sub-exhaust path 48 made of a pipe path 50 and a catalyzer 54 is received in the pipe path 50 while the base end side of pipe path 50 communicates to the atmosphere through a through hole 58, an expansion chamber 23 and an idle relief hole 24.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exhaust purification device for marine propulsion devices such as outboard motors and inboard/outboard motors, and in particular, the present invention relates to an exhaust purification device for marine propulsion devices such as outboard motors and inboard/outboard motors. This invention relates to an exhaust gas purification device for ship thrusters.

[Conventional technology]

As a conventional exhaust system for a 4-liter vessel, exhaust gas is discharged into the atmosphere through a muffler, etc., as described in Japanese Utility Model Application Publications No. 19082/1982 and No. 19083/1983. Things to do 1 For example, JP-A-50-10043
There are those that discharge the exhaust gas into water as shown in Japanese Utility Model Publication No. 1987-45199, and those that discharge the exhaust gas into both water and the atmosphere as shown in Japanese Utility Model Publication No. 58-45199.

In these conventional marine propulsion systems, especially those that discharge exhaust only into the atmosphere, it is necessary to prevent air pollution caused by CO and HC in the exhaust, and to remove white smoke and bad odors caused by these harmful components. However, it has been proposed to install a catalyst in the exhaust passage for the purpose of
Regarding the type of exhaust gases that emit into the atmosphere, there are no catalysts installed to purify the exhaust gas.

Therefore, the applicant first installed a catalyst in a position facing the exhaust port of the engine in a type of marine thruster that discharges exhaust gas both into the water and into the atmosphere, so that part of the exhaust gas passes through this catalyst. We proposed an exhaust purification system in which the remaining part is discharged into the atmosphere, and the remaining part is discharged into water. (Special application No. 61-4342
No. 4, filing date February 28, 1986).

[Problem to be solved by the invention] In the proposal of this applicant, since the catalyst is placed opposite to the exhaust port of the engine, it has the advantage that the reaction temperature of the catalyst can be raised sufficiently, but on the contrary, the exhaust gas There is a risk that the temperature of the catalyst will rise due to this, causing problems. In other words, since this catalyst is located opposite the exhaust port, it must be supported by an inner cover that constitutes the engine body, or it will become extremely high temperature due to heat transfer from the inner cover or the catalyst, resulting in ripe distortion. This may cause problems such as cooling water leakage.

The present invention has been developed in view of this point, and its purpose is to prevent the heat from the catalyst from being directly transmitted to the members constituting the engine body, thereby suppressing distortion of the members due to heat as much as possible. An object of the present invention is to provide an exhaust purification device for a ship propulsion device that prevents leakage of cooling water.

[Means to solve the problem]

The present invention includes a main exhaust passage for discharging engine exhaust into water and a sub-exhaust passage for discharging the exhaust into the atmosphere, and the main exhaust passage is provided in direct communication with an exhaust port of the engine and one side thereof. In a marine propulsion device partitioned by an inner cover of an engine, a branch port is provided in a part of the inner cover, and the sub-exhaust passage is branched from the branch port, and the sub-exhaust passage is separated from the inner cover. It is made of a material, and a catalyst is disposed within the sub-exhaust passage.

[Effect]

In the exhaust purification system with the above configuration, part of the exhaust gas discharged from the exhaust port of the engine cylinder is discharged into the water via the main exhaust passage, and the rest passes through the catalyst through the auxiliary exhaust passage. Here, it is thoroughly purified and discharged into the atmosphere. Here, when the ship is at low or medium speed, the back pressure in the main exhaust passage that opens into the water is high, and therefore most of the exhaust gas is discharged into the atmosphere from the sub-exhaust passage. On the other hand, when a ship is propelled at high speed, the back pressure at the underwater opening of the main exhaust passage becomes low, and most of the exhaust gas is discharged into the water from the main exhaust passage and also into the atmosphere from the auxiliary exhaust passage. Ru.

The auxiliary exhaust passage is branched from the main exhaust passage and is made of a separate member from the inner cover, which is part of the engine body, so the heat from the catalyst in the auxiliary exhaust passage is not directly transmitted to the inner cover. Therefore, there is not much aging distortion in the engine body.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIG. 2 is a sectional view of a main part of an exhaust section of a marine propulsion device showing an embodiment of the present invention.

An extrauterine engine 12 is attached to the hull 11 as a ship propulsion device. The extrauterine motor 12 includes a clamp flaket 13 that is rotated by the hull 11, a swivel bracket 14 that is held by the clamp flaket 13 in a vertically tiltable manner, and a horizontal direction with respect to the swivel bracket 14. It has a casing 15 which is held in rotation.

An engine 16 is located in the upper part of the casing 15, and a lower casing 18 that rotatably holds a propeller 17 is attached to the lower part. engine 16
A transmission device 21 for transmitting power is provided between the propeller 17 and the propeller 17.
The power generated by the engine 16 is transmitted to the propeller 17 via the transmission device 19, and the propeller 17 propels the boat.

Exhaust gas from the engine 16 is led into a first expansion chamber 21 formed in the casing 15 through a part of the exhaust pipe 20, and is discharged into the water through a main exhaust passage 22 formed in the lower casing 18. . That is, this exhaust pipe 20, the first
The expansion chamber 21 and the main exhaust passage 22 constitute a part of the main exhaust passage for discharging the exhaust gas into the water.

The other part of the exhaust gas is led to a second expansion chamber 23 formed integrally with the casing 15 and from there to the casing 15.
It is designed to be discharged into the atmosphere through an idle relief hole 24 formed in the hole. That is, the second expansion chamber 23 and the idle relief hole 24 constitute a part of the sub-exhaust passage.

Incidentally, reference numeral 25 is a cooling water pump driven by the transmission device 19, which sends cooling water to the engine 16 through a cooling water pipe 26.

A cross-sectional view of an engine 16 is shown in FIG. 1, and this embodiment uses a two-stroke, two-cylinder engine.

Here, the cylinder block 30 that integrally constitutes two cylinders has a scavenging port 32 and an exhaust port 33 for each cylinder.
has. Exhaust gas is discharged from the exhaust port 33, or the starting end of a main exhaust passage 38 is formed in a state where the exhaust port 33 directly communicates with the exhaust port 33, and one side of the main exhaust passage 38 is partitioned by the inner cover 40 of the engine 16. It is formed and extends, and is connected to the exhaust pipe 20 after being slightly bent between the cylinder block 30 and the cylinder block 30 .

An outer cover 44 is attached to the outside of the inner cover 40 via a gasket 42, or a portion of the inner cover 40 protrudes outward beyond the outer cover 44 to form a branch port 46. This branch port 46
is the starting end of the sub-exhaust passage 48, and is connected to the branch port 46 via a gasket 52 or a conduit 50 constructed of a separate member from the inner cover 40. A catalyst 54 is housed within the conduit 50, and the sides of the catalyst 54 are covered with a mat 56 made of a well-known heat-expandable ceramic material. The proximal end side of this conduit 50 is communicated with the second expansion chamber 23 provided in the casing 15 described above through a t″V through hole 58 formed in the cylinder block 30, and this second expansion chamber Exhaust from 23 or idle relief hole 21
1 to the atmosphere.

In addition, the code|symbol 60 in a figure is a bottom cowling.

62 is a seal, 64 is an upper case sink, and 66 is a water jacket. Preferably, the conduit 50 containing the 111th infiltrator 54 is protected by a protective cover 68.

According to the above configuration, the exhaust gas coming out of the exhaust port 33 of the engine is divided into two directions from the main exhaust passage 38, and one side goes to the exhaust pipe 20, the first expansion chamber 21, and the lower exhaust passage 22. You will be guided along the path that will lead you there. The other one enters the auxiliary exhaust passage 48 from the branch port 46 of the inner cover 40, is purified by the catalyst 54, and then enters the through hole 58. It is guided to a path leading to the second expansion chamber 23 and the idle relief hole 24.

However, when a ship is propelled at low or medium speeds, the exhaust gas contains a large amount of CO and HC due to incomplete combustion. However, in this case, the back pressure at the opening of the main exhaust passage under water is high, so that no exhaust gas flows into the main exhaust passage, and most of the exhaust gas is led to the auxiliary exhaust passage 48, purified by the catalyst 54, and then released into the atmosphere. is discharged.

On the other hand, when the ship is moving at high speed, the back pressure in the water is low and the exhaust gas is mainly discharged into the water through the north exhaust passage due to the suction effect of the propeller 17.

In this case, the right three components of the exhaust itself have been removed and reduced by complete combustion at high speeds, so there is no problem.
In reality, some exhaust gas is also discharged into the fire from the auxiliary exhaust passage.

Note that the sub-exhaust passage 48. In particular, the catalyst 54 is substantially separated from the engine body, i.e., the cylinder block 3
0. Since the engine 7, which is composed of an inner cover 40 and an outer cover 44, is placed outside the body, even if the catalyst 54 reaches a very high temperature, the heat will not be directly transmitted to the inner cover 4.
0 and the outer cover 44, therefore, problems such as leakage of cooling water due to thermal distortion are prevented.

[Effect of the invention] As shown in I-hi, according to Thu: A'11, it is possible to dispose the catalyst substantially separated from the engine body and to directly transmit the heat from the catalyst to the engine body. This has an excellent effect in that it can eliminate problems such as leakage of cooling water caused by distortion due to heat.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of an embodiment of the exhaust gas purification device for a marine thruster according to the present invention, and FIG. 2 is a partially cutaway front view showing an outboard motor to which the same embodiment is applied. It is. 16... Engine 33... Exhaust port 38... Main exhaust passage 40... Inner cover 46... Branch port 48... Sub-exhaust passage 50... Pipe line 54... Catalyst agent Patent Attorney Yoshiyuki Inako Figure 1

Claims (1)

[Claims] The main exhaust passage includes a main exhaust passage for discharging engine exhaust into water and a sub-exhaust passage for discharging the exhaust into the atmosphere.
In a marine propulsion device, which is provided in direct communication with an exhaust port of an engine and whose one side is partitioned by an inner cover of the engine, a branch port is provided in a part of the inner cover, and the branch port is connected to the auxiliary exhaust passage. An exhaust gas purification device in which the sub-exhaust passage is formed by a separate member from the inner cover, and a catalyst is disposed within the sub-exhaust passage.