JPH11105792A - Exhaust device for marine engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate various work, such as extracting exhaust gas in a exhaust pipe. SOLUTION: This device is provided with a water jacket in an exhaust pipe 16 with a catalyst disposed in the upstream of an exhaust gas passage, and a temperature sensor for detecting the temperature of an exhaust system. An exhaust gas extraction opening 26 is formed at the exhaust pipe 16, and an exhaust gas extraction pipe for extracting the exhaust gas in the exhaust pipe 16 and plug 40 are selectively-fitted to the exhaust gas extraction opening 26 so as to be detachable. A cover 45 is fitted at the outer surface of the exhaust pipe 16 so as to cover the exhaust gas extraction opening, and at least a part for covering the exhaust gas extraction opening 26 in the cover 45 is formed so as to be capable of being opened and closed. A cooling water delivery opening for delivering the cooling water of an engine 8 directly into the exhaust gas passage of the exhaust pipe 16 is formed at the exhaust pipe 16, and the exhaust gas extraction opening is formed in the upstream of the cooling water discharge opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a ship engine.

[0002]

2. Description of the Related Art Among conventional marine propulsion devices, a water jet propulsion device used for a watercraft is configured to drive a jet pump with a two-cycle engine, and uses water sucked from outside the ship as cooling water as an exhaust pipe. An exhaust device for cooling the device is provided. The cooling water is configured to be pressure-fed to a water jacket of an engine and an exhaust pipe by a pressure of the jet pump from a cooling water inlet opened to a propeller chamber of the jet pump. It is also considered that the catalyst is installed in the exhaust pipe, and the exhaust pipe is cooled by introducing cooling water from the water jacket of the engine between the inner pipe and the outer pipe as a double pipe structure. The cooling water is discharged into an exhaust passage upstream of a water lock provided in an exhaust system.

[0003]

In the above configuration, it is conceivable to employ a configuration in which the exhaust gas in the exhaust pipe is sampled in order to detect the degree of purification of the exhaust gas by the catalyst. In that case, when sampling of the exhaust gas is not performed, it is necessary to attach a plug to the exhaust gas sampling port to prevent the exhaust gas from leaking therefrom. Rust is generated around the plug, which hinders the attachment and detachment of the plug, which may make it difficult to collect exhaust gas.

The present invention has been made to solve such a conventional problem, and provides an exhaust device for a ship engine that can easily perform a work of collecting exhaust gas from an exhaust pipe. Things.

[0005]

According to a first aspect of the present invention, there is provided an exhaust system for a ship engine in which a catalyst is provided in an exhaust pipe, wherein an exhaust gas sampling port is formed in the exhaust pipe downstream of the catalyst. An exhaust gas sampling pipe and a plug for sampling exhaust gas in the exhaust pipe are detachably and selectively attached to the gas sampling port, and a cover is attached to an outer surface of the exhaust pipe so as to cover the exhaust gas sampling port. At least a portion of the cover that covers the exhaust gas sampling port is configured to be openable and closable.

According to the first aspect of the present invention, when collecting exhaust gas, the cover or a part thereof may be opened and closed, and the exhaust gas sampling port is sealed with a plug when not used, and this part is covered with the cover. As a result, rust is prevented from being generated around the plug by seawater or the like, so that the exhaust gas can always be easily collected.

According to a second aspect of the present invention, a water jacket is formed in the exhaust pipe, and a cooling water discharge port for directly discharging cooling water flowing through the water jacket into an exhaust gas passage of the exhaust pipe is formed. The exhaust gas sampling port is formed on the upstream side of the cooling water discharge port.

According to the second aspect of the present invention, since the exhaust gas sampling port is provided on the upstream side of the cooling water discharge port, the cooling water discharged into the exhaust gas from the cooling water discharge port at the time of collecting the exhaust gas can be removed. , And the exhaust gas can be measured accurately.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view of a ship to which the present invention is applied, in which a bottom is cut away, FIG. 2 is a plan view thereof, FIG. 3 is a rear view of a partially cutaway engine, and FIG. 5 is a partial cross-sectional front view of FIG. 4, FIG. 6 is a cross-sectional view taken along line AA of FIG. 5, FIG. 7 is a schematic diagram of an exhaust device, and FIG. FIG. 3 is a diagram illustrating a relationship between a gas temperature and a distance from a catalyst.

In FIG. 1 to FIG. 3, a steering handle 4 is provided at the upper part of the hull 2 of the watercraft 1 at a position slightly forward of the center and on the hull center line. A seat 3 is provided, and foot steps 2a are formed on both sides thereof.

The interior of the hull 2 is partitioned forward and backward by a bulkhead 5 rising from the bottom 2b. An engine room 6 is formed at the front of the bulkhead 5, and a pump room 7 is formed at the rear. An engine 8 is installed in the engine room 6 below the seat 3 and at the center of the hull 2 in the left-right direction, and a fuel tank 9 is arranged in front of the engine 8.
The seat 3 is detachably attached to the hull, and is configured to cover and close the maintenance opening 2c of the engine 8 from above with the seat 3.

The engine 8 is a water-cooled, two-cycle, two-cylinder engine having two cylinders arranged in the front-rear direction of the hull 2 and connected to drive a jet pump 10 provided at the rear of the hull 2. A water jet propulsion device that drives the watercraft 1 together with the jet pump 10 is configured. The engine 8 is configured to draw water outside the hull from the propeller chamber 10a of the jet pump 10 and use it as engine cooling water. The pressure for guiding the engine cooling water to the engine 8 is controlled by the propeller chamber 10a.
Utilizes the pressure inside.

The engine 8 has an intake device 11 extending upward from the crankcase 8a to the starboard side of the hull, and an exhaust device 12 to the cylinder body 8b on the port side of the hull. The intake device 11 includes a carburetor 11a, an intake silencer 11b, and the like. Further, the ignition system of the engine 8 stops supplying power to a not-shown spark plug when the engine 8 is in an overrev state due to a remarkable increase in the engine speed, causing the engine 8 to misfire and the rotation to rise further. It is configured to prevent

The exhaust device 12 is connected to an exhaust port on the port side of the hull of the cylinder body 8 and connects the exhaust passage to the engine
An exhaust manifold 13 extending forward of the exhaust manifold 13; an exhaust chamber 14 connected to the downstream end of the exhaust manifold 13 and extending in the stern direction above the crankcase 8a;
An exhaust pipe 16 connected to the rear end of the exhaust chamber 14 and extending to the lower right when viewed from the front of the hull behind the engine; and a water connected to the rear end of the exhaust pipe 16 via a rubber communication hose 17. Lock 18 and this water lock 18
And a discharge pipe 19 extending upward from the upper portion of the jet pump, traversing above the jet pump 10, and extending downward on the starboard side and connected to the side wall of the jet pump storage chamber. A catalyst 20, which will be described later, is disposed inside a connection portion between the exhaust chamber 14 and the exhaust pipe 16.

Since the exhaust device 12 is housed in the hull 2 and cannot be expected to be cooled by wind when the ship is running,
A structure for cooling with engine cooling water is employed. That is, the exhaust manifold 13, the exhaust chamber 14, and the exhaust pipe 16 are integrally formed in a double pipe structure by casting, and a space formed between an inner pipe and an outer pipe of the double pipe is formed in a cooling water passage. The engine cooling water flows through the water jacket.

4 to 6, the exhaust pipe 16 has a water jacket formed by a double pipe composed of an inner pipe 16a and an outer pipe 16b, and has an annular shape formed between the inner pipe and the outer pipe. The cooling water passage W is formed by the gap, and the inner pipe 16
An exhaust passage S is formed inside a. Similarly, the exhaust chamber 14 is formed as a double pipe including an inner pipe and an outer pipe. Similarly, the exhaust manifold 13 is formed as a double pipe by an inner pipe and an outer pipe, and a cooling water passage W is formed by a gap between these pipes. A catalyst holding flange 15 is interposed between the exhaust chamber 14 and the exhaust pipe 16, and a cooling water passage W that connects the exhaust chamber 14 and the cooling water passage of the exhaust pipe 16 is formed in the flange 15.

The catalyst 20 held by the catalyst holding flange 15 is formed by fixing a carrier 20a made of alumina or the like having a honeycomb cross section supporting a catalyst metal inside a metal holding cylinder 20b. The metal holding cylinder 20b is fixed to the catalyst holding flange 15. A temperature sensor 21 for exhaust gas flowing inside and a temperature sensor 22 for exhaust pipe are attached to the exhaust pipe 16 on the downstream side of the catalyst 20. The temperature sensor 21 for the exhaust gas has a center Ec of the exhaust passage S whose tip end of the temperature detecting portion 21a is close to the outlet side of the catalyst 20.
It is attached to be located in. The exhaust pipe temperature sensor 22 is mounted on the pipe wall of the exhaust pipe 16 located on an extension of the center Ec of the exhaust passage S. These mounting positions are preferable for detecting the temperature of the exhaust gas immediately after passing through the catalyst 20 and the temperature of the pipe wall, and the mounting position of the temperature sensor 22 for the exhaust pipe is preferably in the downstream part of the exhaust pipe 16. It may be.

The upper side of the engine 8 is shown in FIGS.
As shown in FIG. 2, a maintenance opening 2c which can be opened and closed by the seat 3 is formed, and a person checks the engine 8 through this opening 2c.
It is preferable that the reference numerals 1 and 22 are arranged so as to face upward through the opening 2c, that is, such that the upper side is not covered by other engine parts and is located inside the periphery of the opening 2c.

As shown in FIG. 5, the exhaust pipe 16 is formed with a drain port 16c of a cooling water passage W, from which a part of the cooling water is discharged as pilot water to the outside of the ship through a water distribution pipe (not shown). And thereby the exhaust system 12
The driver can confirm that the engine cooling water is flowing through the vehicle. At the rear end of the exhaust pipe 16, an orifice member 24 formed in a metal annular shape is provided with a screw 24.
The throttle member 24 is formed in a shape that covers the cooling water outlet 23 of the cooling water passage W, and the cooling water from the cooling water passage W is connected to the upper and lower two places by the communication hose 17.
A cooling water hole 24a to be discharged into is formed.

Since the communication hose 17 is disposed substantially horizontally, the engine cooling water flowing into the communication hose 17 mainly flows below the communication hose 17. For this reason,
The upper part of the communication hose 17 is easily heated by the exhaust gas. In order to prevent this, an inner tube 25 made of an aluminum alloy is inserted into the inner surface of the communication hose 17 by insert molding so as to cover the inner surface over the entire circumference, thereby transmitting heat given to the upper portion to the lower portion. The heat is absorbed by the engine cooling water flowing through the lower part.

As shown in FIGS. 4 and 5, a cooling water discharge port 27 for discharging engine cooling water from the engine 8 directly into the exhaust pipe 16 is formed at an intermediate portion of the exhaust pipe 16. The cooling water outlet 27 and the cooling water hole 24
An exhaust gas sampling port 26 is formed on the upstream side of a, and an exhaust gas sampling pipe 33 is screwed into a screw formed in the exhaust gas sampling port 26, and the exhaust gas in the exhaust passage S is sampled therefrom. Like that. Although the exhaust gas passing through the catalyst 20 has a high temperature immediately after the catalyst 20 as shown in FIG. 8, the temperature rapidly decreases thereafter, the combustion ends, the gas temperature decreases, and the gas components are stabilized. An exhaust gas sampling port 26 is provided in an area (farther than the point P in the figure). When this gas sampling is not performed, the exhaust gas sampling pipe 33 is removed from the exhaust gas sampling port 26, and the plug 40 is screwed in as shown in FIG. 3 to close the exhaust gas sampling port 26 with a seal structure. .

The exhaust gas sampling port 26 is connected to the cooling water hole 24.
a and the cooling water discharge port 27 are provided upstream so that the cooling water discharged from the cooling water hole 24a and the cooling water discharge port 27 is not collected together with the gas when the exhaust gas is collected, Thus, the measurement of the exhaust gas can be performed accurately. Further, the cooling water discharge port 27 is formed toward the downstream side for the same purpose.

A cover 45 made of an aluminum alloy is attached to the outer surface of the exhaust pipe 16 so as to cover the exhaust gas sampling port 26, and a high-temperature portion of the exhaust pipe 16, that is, a portion immediately after the rear end of the catalyst 20, is external. Not to be exposed. As the attachment means, as shown in FIG. 5, a boss 160 is provided at an appropriate position of the exhaust pipe 16 so as to protrude therefrom, and the boss 160 may be fixed by tightening the screw 41 through the cover 45. And the exhaust gas sampling pipe 3
When attaching the screw 3 to the exhaust gas sampling port 26,
By removing the cover 1, the cover 45 may be removed.
The portion of the exhaust gas sampling port 26 is formed by forming a concave portion 42 in a cover 45 as shown in FIG.
Instead of forming the concave portion 42 integrally with the cover 45 in this manner, an openable / detachable small cover constituted by a member separate from the cover 45 is attached to a portion corresponding to the concave portion 42, and the small cover is opened / closed or detached. By doing so, the plug 40 and the exhaust gas sampling pipe 33 may be attached and detached. In this case, the cover 45 need not be attached or detached, and only the small cover needs to be opened and closed or detached, so that the work can be easily performed.

FIG. 7 is a schematic diagram of a control unit of the exhaust device.
The detection signals from the temperature sensors 21 and 22 are input to the control unit 50, a predetermined warning display is displayed on the meter 51 by the signal from the control unit 50, and a predetermined warning sound is emitted by the buzzer 52. These displays are used to identify and display each abnormal state such as a first warning temperature (preliminary warning temperature), a second warning temperature, and other system failures, so that the driver can know what abnormality is present by the display. Have to be able to. The engine 8 is configured to start and stop based on a signal from the control unit 50. Note that the temperature sensor 22 may be provided downstream of the exhaust pipe 16 as indicated by a virtual line.

In the above configuration, since the high temperature portion of the exhaust pipe 16 which is heated by the exhaust gas is covered with the cover 45, the inspection work of the engine 8 and the like can be easily performed. 45 or a part thereof may be opened and closed or detached. Further, the exhaust gas sampling port 26 is sealed with a plug 40 when not in use, and since this part is covered with the cover 45, it is exposed to seawater or the like to prevent the plug from being plugged. It is also possible to prevent the generation of rust around, and it is possible to easily collect the exhaust gas at all times.

[0026]

According to the first aspect of the invention, the exhaust gas may be collected by opening and closing the cover or a part of the cover, and the exhaust gas sampling port is sealed by a plug when not in use. Because of this, it is possible to prevent rust around the plug due to splashing with seawater and the like, so that the exhaust gas can always be easily collected.

According to the second aspect of the present invention, since the exhaust gas sampling port is provided on the upstream side of the cooling water discharge port, the cooling water discharged from the cooling water discharge port into the exhaust gas at the time of collecting the exhaust gas is subjected to gas discharge. , And the exhaust gas can be measured accurately.

[Brief description of the drawings]

FIG. 1 is a side view of a ship to which the present invention is applied, in which a bottom portion is cut away.

FIG. 2 is a plan view of FIG.

FIG. 3 is a partially cutaway rear view of the engine of FIG. 2;

FIG. 4 is a longitudinal sectional view of the exhaust pipe with a cover removed.

FIG. 5 is a partial sectional front view of FIG. 4;

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a schematic diagram of a control unit of the exhaust device.

FIG. 8 is a diagram showing a relationship between an exhaust gas temperature in an exhaust pipe and a distance from a catalyst.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Watercraft 3 Straddle type seat 4 Steering handle 6 Engine room 7 Pump room 10 Jet pump 10a Propeller room 11 Intake device 12 Exhaust device 13 Exhaust manifold 14 Exhaust chamber 15 Catalyst holding flange 16 Exhaust pipe 17 Communication hose 18 Water lock Reference Signs List 20 catalyst 21 temperature sensor for exhaust gas 22 temperature sensor for exhaust pipe 26 exhaust gas sampling port 27 cooling water discharge port 33 exhaust gas sampling pipe 40 plug 45 cover 50 control unit 51 meter (display device) 52 buzzer (display device) W cooling water Passage S Exhaust gas passage

Claims (2)

[Claims] In an exhaust system for a ship engine having a catalyst installed in an exhaust pipe, an exhaust gas sampling port is formed in an exhaust pipe downstream of the catalyst, and the exhaust gas sampling port has an exhaust gas in the exhaust pipe. An exhaust gas sampling pipe and a plug for collecting the gas are selectively attached detachably, and a cover is attached to an outer surface of the exhaust pipe so as to cover the exhaust gas sampling port,
An exhaust device for a ship engine, wherein at least a portion of the cover that covers the exhaust gas sampling port is configured to be openable and closable. 2. A water jacket is formed in the exhaust pipe, a cooling water discharge port for discharging cooling water flowing through the water jacket directly into an exhaust gas passage of the exhaust pipe is formed, and the exhaust gas sampling port is provided. The exhaust device for a ship engine according to claim 1, wherein the exhaust device is formed upstream of the cooling water discharge port.