JPH02256814A - Catalyst retaining portion cooler for small-sized jet-propelled boat - Google Patents

Abstract

PURPOSE:To cool effectively the perimeter of a catalyst without using a water pump by utilizing cooling water taken in by means of a jet propeller or water discharged after engine cooling, as cooling water cooling a catalyst retaining portion. CONSTITUTION:A hull 1 is propelled as high pressure water generated by turning an impeller 7 through the drive of an engine 3 is jetted into the water through a steering nozzle 9. Hereupon, when the exhaust gas of the engine 3 is exhausted via an exhaust manifold 15, an exhaust muffler 17, it comes into contact with a catalyst 20 and physical/chemical reaction treatments are made, and discharge into atmosphere as a clean gas is made. At this time, part of the high pressure water flows into a water cooling jacket 23 via a hose 27, a cooling water entrance 25, and the catalyst 20 reaction heat exerting effect on perimeter apparatus on the outside is prevented. As a result, a cooling water supplier such as a water pump or the like becomes unnecessary, and a catalyst retaining portion cooler can be obtained at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a cooling device for a catalyst holding part of a small jet propulsion watercraft.

(Conventional technology) CO contained in exhaust gas even in small boat engines.
It is desired that air pollution prevention measures be taken to prevent harmful components such as carbon dioxide and HC from being released into the atmosphere.

As such an engine for a small boat, an outboard motor equipped with an exhaust purification device using a catalyst is known (Japanese Patent Publication No. 18009/1982). In this exhaust purification system, a catalyst is installed in the exhaust gas passage, and the harmful components contained in the exhaust gas are burned and removed by the heat of reaction with the catalyst. A cooling device is provided that cools the catalyst holding section with cooling water so as not to affect the catalyst holding section.

(Problem to be Solved by the Invention) However, in the case of an outboard motor as described in the above publication, cooling water branched from the water pump is supplied to both the engine and the catalyst holding section, respectively. The load on the water pump is heavy, and therefore the pump performance must be improved, which in turn increases costs and has to bear various disadvantages such as changing the mounting part and increasing mechanical loss. Furthermore, there were many inadequacies, such as the inability to objectively grasp the functional status of the catalyst and reliance on visual inspection, making it impossible to apply this technology to the engines of small jet propulsion boats.

This invention makes it possible to effectively cool the area around a catalyst that reacts with and purifies harmful components in the exhaust gas of the engine of a small jet propulsion boat without using a water pump, and also allows the driver to see the functional status of the catalyst. It is an object of the present invention to provide a cooling device for a catalyst holding part of a small jet propulsion boat that can notify the user.

(Structure of the Invention) (Means for Solving the Problems) As a means for solving the problems of the above-mentioned prior art, a catalyst holding part cooling device for a small jet propulsion boat according to the present invention has the following features:
A small jet propulsion boat has a jet propulsion machine that drives an impeller by the rotation of the engine, and propels the boat by injecting high-pressure water generated by the drive of the impeller from a nozzle at the stern.A catalyst is installed inside the exhaust passage of the engine. A water cooling jacket is provided surrounding the installation position of the catalyst via a heat insulating layer, and the cooling water inlet of this water cooling jacket and the jet semi-advancement are communicated through a cooling water intake passage, and the water cooling jacket is cooled. A drainage passage is connected to the water outlet, a temperature sensor is installed in this drainage passage, and this temperature sensor detects the temperature of the catalyst. Il! It is designed to detect the situation.

In addition, in order to solve the above-mentioned problems, the catalyst holding part cooling device for a small jet propulsion boat according to the present invention drives an impeller by the rotation of the engine, and the high-pressure water generated by driving the impeller is sent from a nozzle at the stern. In a small jet propulsion boat having a jet propulsion device that propels the hull by injecting water, a catalyst is installed inside the exhaust passage of the engine, and a water-cooled jet 1 surrounds the installation position of the catalyst via a heat insulating layer.
! A cooling water inlet of the water cooling jacket and a cooling water outlet of the engine are communicated with each other through a cooling water intake passage, and a drainage passage is connected to the cooling water outlet of the water cooling jacket, and a temperature sensor is installed in this drainage passage. A temperature sensor is provided to detect the functional status of the catalyst.

(Operation) High-pressure water generated by driving the engine and rotating the impeller is injected into the water from the nozzle, propelling the ship. When exhaust gas from an engine is exhausted through an exhaust passage, it comes into contact with a catalyst, undergoes physical and chemical reactions, and is released into the atmosphere as clean gas. At this time, a portion of the high-pressure water flows into the water-cooling jacket through the cooling water intake passage, preventing the reaction heat of the catalyst from affecting external peripheral equipment. After cooling the catalyst holding part, the cooling water is discharged from the cooling water outlet through the drainage passage, but at this time, the temperature of the cooling water is detected by a temperature sensor, and the driver is informed by a display means such as lighting a lamp or a buzzer. The functional status of the catalyst is informed.

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

1 and 2 show the overall structure of a small jet propulsion boat equipped with the present invention.This small jet propulsion boat has an engine room 2 defined approximately in the center of a hull 1; An engine 3 is installed inside the engine 2.

An impeller shaft 4 is connected to the output shaft of this engine 3 by a coupling 5, and this impeller shaft 4 extends to the rear of the hull 1 through a duct 6, and an impeller 7 is fixed to the tip side thereof. The impeller 7 constitutes a diene propulsion unit 10 including a shroud casing 8 surrounding the impeller 7, a steerable steering nozzle 9 for injecting high-pressure water generated by the rotation of the impeller 7, and the like. In the figure, 11 is an engine cover, 12 is a handle ball of a steering device, 13 is a handle, and 14 is a water intake port opened at the bottom of the hull 1.

On the other hand, an exhaust muffler 16 is connected to the exhaust manifold 15 of the engine 3, and an exhaust pipe 17 connected to the exhaust muffler 16 is guided to the bow of the ship and discharges exhaust gas into the atmosphere through a muffler 18. It has become.

An exhaust gas purifying catalyst 20 is internally installed in the exhaust passage leading to the exhaust muffler 16. For example, as shown in FIG. 3, this catalyst 20 is fitted and held in the inner periphery of a water-cooled jacket member 21 connected between an exhaust manifold 15 and an exhaust muffler 16. This water cooling jacket member 21
constitutes a catalyst holding section cooling device.

The water cooling jacket member 21 has two almost concentric chambers in the circumferential direction, the inner chamber is filled with a heat insulating material 22 to form a heat insulating layer, and the outer chamber is liquid-tight. The water cooling jacket 23 is A gasket 24 seals between the heat insulating layer and the water cooling jacket 23. The heat insulating layer has a mounting surface that keeps the catalyst 20 warm, and the heat insulating layer allows the catalyst to maintain a temperature at which the chemical reaction of the catalyst is promoted, for example from 600°C.
It is designed to be kept at around 800°C.

This water cooling jacket 23 has a cooling water population 25 and an outlet 26.
and is provided. The water cooling jacket 23 cools the heat insulating layer from the outside and prevents the adverse effects of the reaction heat generated by the catalyst 20 from reaching the surrounding area. The cooling water inlet 25 is connected to a hose 27 constituting a cooling intake passage, and this hose 27 is connected to the high pressure side elbow portion 28 of the shroud casing 8 provided in the jet propulsion machine 10. High pressure water is introduced into the water cooling jacket 23 from the water cooling jacket 23. Further, this high-pressure water may be mainly used as engine cooling water. A drain hose 29 constituting a drain passage 29a is connected to the cold W water outlet 26, and a temperature sensor 3o is provided in the drain passage 29a via a mounting plug 31 as shown in FIG. Water is drained through the passageway.

By the way, regarding the WQ installation position of the catalyst and the configuration of the holding portion, the catalyst 2o may be installed inside the joint of the exhaust pipe 16 as shown in FIGS. 5 and 6. Specifically, the first pipe element 1 of the exhaust vibe 16
The catalyst 2o may be internally installed at the joint between the catalyst 6a and the second pipe elm l-16b, the heat insulating material 22 may be placed around the catalyst 2o, and the surrounding area may be used as a water cooling jacket 23 to allow water to flow therethrough.

In addition, without directly guiding the pressure cooling water from the jet propulsion machine 10 to the water cooling jacket 23, as shown in FIG.
A fitting hose 36 is provided on the cylinder head 35 of the engine 3, and a Y-shaped pipe 37 is connected to the fitting hose 36 directly or indirectly. A drainage hose (not shown) is connected to one side of the Y-shaped pipe 37 and water is discharged to the sea, while the other side is connected to the cooling water inlet 25 of the catalyst holder cooling device, and the water is discharged through the cooling water intake passage 38. For example, engine cooling waste water at about 60° C. may be supplied to the water cooling jacket 23 of the catalyst holding portion cooling W device. In this case, cooling water pumped from the jet propulsion device 10 by a cooling water hose is used to cool the engine, and a water pump may be provided in the middle of this cooling water passage, if necessary.

Furthermore, instead of providing the Y-shaped pipe 37, a plurality of fitting hoses 36, for example two fitting hoses 36, are provided in the cylinder head 35 of the engine 3 as shown in FIG. It may also be connected to supply a catalyst holding unit cooling device.

Next, the action will be explained.

When the engine 3 is driven to rotate the impeller 7, water is sucked in from the water intake port 14 of the shroud casing 8, compressed, and injected from the steering nozzle 9 as high-pressure water, and the hull 1 is propelled by the reaction force.

On the other hand, the exhaust gas of the engine 3 is transferred to the exhaust manifold 15.
The exhaust gas is then discharged through the exhaust muffler 16, the exhaust pipe 17, and the muffler 18, but in the meantime, the exhaust gas purifying catalyst 20
Harmful components such as CO and HC contained in the exhaust gas are removed by oxidation reaction, and the exhaust gas is purified by chemical reaction treatment and recovery treatment. At the same time, high-pressure water from the jet propulsion 110 or engine cooling waste water is sent into the water cooling jacket 23 of the catalyst holding part through the cooling water intake passage 38 and cooled, and the heat released by the reaction heat of the catalyst 20 is released from the surrounding area. I try not to have any negative impact on the equipment.

When the cooling water that has cooled the catalyst holding part comes out from the cooling water outlet 26, a temperature sensor 30 in the passage detects the temperature of the cooling water and sends a signal to a display means such as a lamp or buzzer to indicate that the catalyst 20 is normal. informs the driver whether the system is functioning or not.

〔Effect of the invention〕

As described above, according to the present invention, the cooling water taken from the jet propulsion machine or the engine cooling water is used as the cooling water for cooling the catalyst holding part! ! Since we are using J drainage,
A cooling water supply device such as a water pump is not required, and the catalyst holding part can be cooled by HfW at low cost. Also, the piping for the vibrators that make up each passage is simplified, which simplifies the construction. It has great advantages in small boats.
Furthermore, by detecting the temperature of the cooling water using a temperature sensor, the driver is informed of the functional status of the catalyst, which provides a sense of security to the driver and is effective in maintaining the engine. There is.

[Brief explanation of drawings]

FIG. 7 is an overall side view showing a small jet propulsion boat to which the present invention is applied, FIG. 2 is a partially sectional side view showing an embodiment of the present invention, and FIG. 3 is a section A in FIG. 4 is an enlarged sectional view of the temperature sensor section provided in the exhaust passage, FIG. 5 is an external view showing another modification of the catalyst holding section,
FIG. 6 is an enlarged sectional view showing part 8 of FIG. 5, and FIG. 7 is a perspective view of a cylinder head portion of an engine used in a small jet propulsion boat. DESCRIPTION OF SYMBOLS 1... Hull, 2... Engine room, 3... Engine, 10... Jet propulsion machine, 2o... Catalyst, 2
3...Water cooling jacket, 30...Temperature sensor. Figure 3: Applicant's agent Hisashi Hatano Figure 4

Claims (1)

[Scope of Claims] 1. A small jet propulsion boat having a jet propulsion device that drives an impeller by the rotation of the engine, and propels the boat by injecting high-pressure water generated by the drive of the impeller from a nozzle at the stern, A catalyst is installed in the exhaust passage of the engine, a water cooling jacket is provided surrounding the installation position of the catalyst via a heat insulating hole, and the cooling water inlet of the water cooling jacket and the jet propulsion machine are connected to the cooling water intake passage. A small jet propulsion boat characterized in that a drainage passage is connected to the cooling water outlet of the water cooling jacket, a temperature sensor is provided in the drainage passage, and the functional status of the catalyst is detected by the temperature sensor. Catalyst holding part cooling device. 2. In a small jet propulsion boat that has a jet propulsion machine that drives an impeller by the rotation of the engine and propels the boat by injecting high-pressure water generated by the drive of the impeller from a nozzle at the stern, a catalyst is installed in the exhaust passage of the engine. A water cooling jacket is provided surrounding the installation position of the catalyst via a heat insulating layer, and the cooling water inlet of the water cooling jacket and the cooling water discharge outlet of the engine are communicated through a cooling water intake passage. A catalyst holder for a small jet propulsion boat, characterized in that a drainage passage is connected to the cooling water outlet of the water cooling jacket, a temperature sensor is provided in the drainage passage, and the functional status of the catalyst is detected by the temperature sensor. Cooling system.