JP2961978B2 - Outboard exhaust purification system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust purification system for an outboard motor.

[0002]

2. Description of the Related Art An internal combustion engine for a vehicle is provided with an exhaust gas purifying apparatus using a catalyst for purifying unburned components contained in exhaust gas by reburning them and releasing them into the atmosphere. In an internal combustion engine of an automobile, a muffler containing a catalyst body in which a catalyst component is attached to a honeycomb-shaped carrier made of ceramics is connected inside an exhaust pipe connected to an exhaust port of the internal combustion engine. When an exhaust gas passes through, an oxidation reaction is caused to reburn and purify unburned components contained in the exhaust gas.
In a small internal combustion engine such as a motorcycle, a catalyst body obtained by attaching a catalyst component to a medium such as glass wool is lined with an inner surface of an exhaust pipe connected to an exhaust port of the internal combustion engine, fastened with a holding piece, and flows through the exhaust pipe. The exhaust gas is brought into contact with the catalyst body to reburn and purify unburned components.

[0003]

However, in the case of a catalyst using a honeycomb-shaped carrier as described above, since the exhaust gas passes through a large number of honeycomb-shaped small holes, the flow path area decreases and the resistance increases. As a result, the output of the engine is reduced, and especially in a small internal combustion engine, the performance disadvantage caused by the reduced output is large. In addition, the catalyst body using the honeycomb carrier has a large volume and a large weight, and accordingly, the exhaust pipe itself has a large volume. On the other hand, a catalyst body made of glass wool or the like is lined on the inner peripheral surface of the exhaust pipe, so that the installation is complicated, the cost is high, and there is a problem in durability.

It is desirable to take exhaust gas purification measures also for an outboard motor, but the outboard motor itself has a small internal combustion engine,
Further, since the exhaust passage is provided in a narrow space in the drive shaft housing, the above-described existing exhaust gas purifying apparatus for a car or a motorcycle cannot be applied. Will be.

The present invention has been made in view of the above problems, and provides an outboard motor exhaust gas purifying apparatus which is compact and easy to install, has good exhaust gas purifying efficiency, and has high durability. The purpose is to:

[0006]

According to the present invention, there is provided an exhaust purification system for an outboard motor, comprising: a catalyst member provided in an exhaust passage of an internal combustion engine; One side of the metal plate bent so as to have two sides is a catalyst side and the other side is a fixed side. A large number of small holes are provided in the catalyst side, and a catalyst component is supported on the front and back thereof. Is fixed inside the exhaust passage near the exhaust port,
One or several catalyst sides are arranged parallel to the exhaust gas flow inside the exhaust passage and upright toward the exhaust port.

[0007]

With this configuration, the volume of the catalyst body is reduced, the exhaust gas purifying device is made very compact, and the exhaust gas purifying device is easily installed in the exhaust passage.

[0008] Exhaust gas emitted from the exhaust port of the internal combustion engine contacts the front and back of the catalyst side standing up to the exhaust port, so that unburned components in the exhaust gas are carried on the front and back of the catalyst side. The exhaust gas is efficiently purified since the catalyst component is sufficiently contacted and oxidized.

Further, since the catalyst body is formed of a metal plate, high durability is provided.

[0010]

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

An outboard motor 1 has an internal combustion engine 4 (a two-stroke two-cylinder in the figure) covered with an engine cover 3 on an upper part of a drive shaft housing 2 as shown in a longitudinal section in FIG. 1 and a plane section in FIG. Engine). The reciprocating motion of the piston 6 that slides in the cylinder 5 of the internal combustion engine 4 is converted by the connecting rod 7 into the rotational motion of the crankshaft 8, and the rotation of the crankshaft 8 is transmitted to the propeller shaft 11 through the drive shaft 9.
The thrust is generated by driving the propeller 12.

An exhaust passage of the internal combustion engine 4 includes an exhaust collective chamber 15 formed by an exhaust cover 14 that covers the exhaust port 13 of the cylinder 5, an exhaust pipe 16 connected to the exhaust collective chamber 15 and extending downward, and a drive shaft. And an exhaust expansion chamber 17 formed inside the housing 2. The exhaust pipe 16 opens downward in the exhaust expansion chamber 17, and the exhaust expansion chamber 17 extends downward to
It is open to the water along 1

For this reason, the exhaust port 13
The exhaust gas that has flowed into the exhaust collecting chamber 15 through the exhaust gas purification device 18 described below purifies unburned components, passes through the exhaust pipe 16 to the exhaust expansion chamber 17, expands, and is discharged into water. You.

FIG. 3 is an enlarged view of a portion III in FIG. 2, and FIG. 4 is a cross-sectional view along the line IV-IV in FIG.

Outboard motor exhaust gas purifying apparatus 18 according to the present invention
Is disposed inside the exhaust gas collecting chamber 15 which is an exhaust passage near the exhaust port 13 and includes one to several metal plates 19 serving as a catalyst.

The metal plate 19 is bent so as to have two sides, one side being a catalyst side 19a and the other side being a fixed side 19b. The catalyst side 19a is wider than the fixed side 19b, and is provided with a large number of small holes 21. As shown in FIG. 5 (a), non-toxic metal, ceramics, cermet or the like is sprayed on the front and back of the catalyst side 19a. A carrier layer 22 having fine irregularities is formed on the surface, and a catalyst solution 23 containing a catalyst component and a catalyst carrier 24 are formed on the surface of the carrier layer 22.
5 is adhered by coating or the like, and is dried and fired to fix the catalyst carrier 24 containing the catalyst component on the surface of the support layer 22 as shown in FIG.

The fixed side 19b of the metal plate 19 is fixed to the inside of the exhaust cover 14 by, for example, rivets 26 or welding, and one to several (three in this embodiment) catalyst sides 19a are connected to the exhaust collecting chamber. 15 and is arranged so as to stand parallel to the exhaust gas flow g inside and toward the exhaust port 13.

At this time, as shown in FIG. 3, the fixed side 19b serves as a spacer which comes into contact with the adjacent metal plate 19, so that it is easy to provide a fixed space between the catalyst sides 19a.

The small holes 21 provided on the catalyst side 19a are:
Since there is no problem even if the metal plate 19 is provided on the fixed side 19b side, a punching plate or the like can be used as the metal plate 19 as it is.

FIGS. 6A to 6M show examples of the shape of the metal plate 19, and FIG.
a is wider than the fixed side 19b, and FIGS. 6B to 6E show the fixed side 1 with respect to the catalyst side 19a.
9b is a non-perpendicular angle, and the catalyst side 19a is a non-flat surface. 6 (F) and 6 (G) show a case where a fold 27 is formed at the center in the longitudinal direction of the catalyst side 19a, and FIGS. 14 shows a modification of the shape. Further, FIG.
(M) is an example in which the catalyst side 19a has a zigzag shape and a wavy shape. As described above, the angle of the catalyst side 19a and the method of forming the fold can be arbitrarily selected.

As described above, the exhaust gas purifying device 18 arranges the catalyst side 19 a having the catalyst component fixed on the front and back so as to rise up toward the exhaust port 13 in parallel with the exhaust gas flow inside the exhaust collecting chamber 15. As a result, the exhaust gas discharged from the exhaust port 13 of the cylinder 5 contacts the entire front and back surfaces of the catalyst side 19a without obstructing the flow thereof, and the unburned components in the exhaust gas are sufficiently converted into the catalyst components. Since the oxidation reaction occurs when touched, the exhaust gas is efficiently purified.

The exhaust gas purifying device 18 has a small volume of the catalyst body and is very compact. Therefore, the exhaust gas purifying device 18 can be accommodated in the internal space of the exhaust gas collecting chamber 15 with a sufficient margin. Can be easily performed, and since the catalyst body is made of a metal plate, it has high durability.

[0023]

As described above, the exhaust gas purification apparatus for an outboard motor according to the present invention has two sides in the exhaust gas purification apparatus for an outboard motor in which the catalyst is provided in the exhaust passage of the internal combustion engine. One side of the bent metal plate is a catalyst side, and the other side is a fixed side. A large number of small holes are provided in the catalyst side, catalyst components are supported on the front and back, and the fixed side is near the exhaust port. It is fixed inside the exhaust passage, and one or several catalyst sides are arranged parallel to the exhaust gas flow inside the exhaust passage and so as to rise toward the exhaust port.

Therefore, the exhaust gas discharged from the exhaust port of the internal combustion engine contacts all over the front and back surfaces of the catalyst side without obstructing the flow, and the unburned components in the exhaust gas undergo an oxidation reaction so that the exhaust gas is decomposed. Purified efficiently.

Further, since the volume of the catalyst body is reduced and the exhaust gas purifying device can be made very compact, even if the internal volume is small as in the exhaust passage of an outboard motor, it can be accommodated without any problem. At the same time, the installation can be performed extremely easily, and the catalyst body is made of a metal plate, so that it has high durability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an outboard motor to which the present invention is applied.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged view of a part III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

5A is a cross-sectional view of a catalyst side showing a state where a slurry of a carrier layer is applied, and FIG. 5B is a cross-sectional view of a catalyst side showing a state after the slurry is dried and fired.

FIGS. 6A to 6M are perspective views each showing an example of a shape of a metal plate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Outboard motor 2 Drive shaft housing 4 Internal combustion engine 5 Cylinder 13 Exhaust port 14 Exhaust cover 15 Exhaust collecting chamber 16 Exhaust pipe 18 Exhaust purification device 19 Metal plate 19a Catalyst side 19b Fixed side 21 Small hole 24 Catalyst carrier 26 Rivet g Exhaust gas Flow

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-85316 (JP, A) JP-A-63-36014 (JP, A) JP-A-61-283713 (JP, A) JP-A-55-1985 14977 (JP, A) Utility model registration 2517030 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 3/00-3/38 B01J 35/02 311

Claims (1)

(57) [Claims] 1. An exhaust purification system for an outboard motor provided with a catalyst body in an exhaust passage of an internal combustion engine, wherein one side of a metal plate bent to have two sides is fixed to a catalyst side and the other side is fixed. A large number of small holes are provided in the catalyst side, and catalyst components are supported on the front and back thereof, and the fixed side is fixed inside the exhaust passage near the exhaust port. One to several catalyst sides are inside the exhaust passage. An exhaust purification system for an outboard motor, wherein the exhaust purification system is arranged so as to be parallel to an exhaust gas flow and to stand toward an exhaust port.