JP3504388B2 - Cooling system for marine engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for a marine engine having an exhaust system provided with a catalyst.

[0002]

2. Description of the Related Art A cooling system for a marine engine supplies cooling water to a cylinder block, flows the supplied cooling water from a cooling jacket around a cylinder bore to a cooling jacket around a combustion chamber of a cylinder head, and from there, cools an exhaust system. It is generally configured to supply near the upstream end of the jacket and to drain into the exhaust pipe from near the downstream end of the expansion chamber (expansion chamber).

[0003]

By the way, recently, in order to purify exhaust gas, it has been considered to dispose a catalyst in the expansion chamber of the exhaust system. When this type of catalyst is provided, the temperature in the vicinity of the chamber is expected to be higher than before. However, in the case of the conventional cooling device, since the catalyst installation site where the temperature rise is expected to be located near the most downstream of the cooling system, for example, the cooling of the cooling water passage is clogged to sufficiently cool the surroundings of the catalyst. There is a possibility that it will not occur.

The present invention has been made in view of the above circumstances, and provides a cooling device for a marine engine which can prevent an exhaust system from abnormally rising in temperature when a cooling water passage is clogged when a catalyst is provided. The purpose is to do.

[0005]

The invention according to claim 1 is exhaust gas
In a cooling device configured to supply cooling water to an engine cooling jacket of a marine engine equipped with a catalyst in a system,
The pressure generation chamber of the propulsion unit that generates propulsive force by pressurizing the water sucked from the bottom of the ship and ejecting it from the stern is connected to the engine cooling jacket to supply cooling water to the engine cooling jacket. A first cooling system for cooling the engine cooling jacket and then draining it is connected to the pressure generating chamber and the exhaust system cooling jacket to supply cooling water to the exhaust system cooling jacket, and the cooling water is supplied to the exhaust system cooling jacket. A second cooling system that cools and then mixes with the exhaust gas and drains the exhaust gas is provided.

According to a second aspect of the present invention, in the first aspect, there is provided an overheat detecting means for detecting an overheat state of the exhaust system, and the second cooling system communicates the pressure generating chamber with the exhaust system cooling jacket. It is characterized in that it is provided with a detachable water supply passage, and has an informing means for informing the outside of the necessity of installing the water supply passage when an overheated state is detected.

According to a third aspect of the present invention, in a cooling device of a marine engine equipped with a catalyst in an exhaust system, the cooling water that has passed through the engine cooling jacket is supplied to an exhaust system cooling jacket. A first cooling that connects a pressure generating chamber of a propulsion unit that generates a propulsive force by pressurizing and ejecting from the stern with an engine cooling jacket, and cools a portion of the exhaust system cooling jacket upstream of the catalyst from the engine cooling jacket. The system, the pressure generating chamber and the exhaust system cooling jacket in the vicinity of the catalyst are communicated,
A second cooling system for cooling the downstream side portion from the vicinity of the catalyst of the exhaust system jacket is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 are views for explaining a cooling device for a marine engine according to a first embodiment of the invention of claims 1 and 2, and FIG. 1 is a partial cross-sectional view of a watercraft equipped with the engine. Left side view, Figure 2 is its plan view,
FIG. 3 is a cross-sectional right side view of the cooling device.

In the figure, a watercraft 1 comprises a hull 2 and
An engine 3 housed and mounted in the hull 2 and a propulsion unit 4 driven by the engine 2 are provided.

The hull 2 is a box-like structure in which a so-called bathtub-shaped hull 5 is mounted with a lid-plate-shaped deck 6 and both are hermetically joined by a gunnel 7. A steering handle 8 is arranged above the front part of the engine 3 of the deck 6, and a saddle type seat 9 is mounted behind the handle 8.

The engine 3 is a water-cooled two-cycle parallel three-cylinder engine, which is constructed by sequentially mounting a cylinder block 11, a cylinder head 12, and a head cover 13 on a crankcase 10.

In the propulsion unit 4, a propulsion duct 14 having a suction port 14a opening toward the ship bottom is disposed in an arrangement space 2a formed in a tunnel shape at the rear of the hull 2, and the rear of the propulsion duct 14 is arranged. The steering nozzle 15 is attached to the discharge port 14b opened to the left and right so as to be swingable right and left around the vertical axis, and the impeller 16 is arranged in the middle of the propulsion duct 14. The steering nozzle 15 is rotated based on the steering operation of the steering handle 8 to change the jetting direction and adjust the traveling direction of the ship. Also, the above impeller 1
6 is fixed to a propulsion shaft 17, and the propulsion shaft 17 is rotationally driven by the crankshaft of the engine 3. In addition,
The rear end portion of the propulsion shaft 17 is supported by a support portion 14c of the propulsion duct 14 via a bearing 18.

The exhaust port of each cylinder of the engine 3 is 1
The two exhaust passages 3a communicate with one common exhaust passage 3a.
The exhaust system 19 is connected to the external connection opening 11b opening at the front end of the. The exhaust system 19 includes an exhaust pipe 20 connected to the external connection opening, an expansion chamber 21 following the pipe 20, and the chamber 21.
The exhaust pipe 23 is connected to the exhaust pipe 23 via the elastic joint 22, and the water lock 24 is provided in the middle of the exhaust pipe 23. The downstream end of the exhaust pipe 23 is open in the arrangement space 2a.

And the expansion chamber 21 described above.
Is divided into front and rear chambers 21a and 21b,
A catalyst 25 is arranged in the vicinity of the divided portion. The catalyst 25 includes a catalyst body 25a and a support plate 25b for positioning the catalyst body 25a at a predetermined position in the chamber 21.
The support plate 25b is sandwiched between the front and rear chambers 21a and 21b. In the vicinity of the downstream side of the catalyst 25, a thermosensor 3 for detecting the temperature of the expansion chamber 21 on the downstream side of the catalyst.
6 are provided.

The exhaust pipe 20 and the expansion chamber 21 have a double pipe structure, and the gap portion of the double pipe serves as an exhaust cooling jacket A. The exhaust cooling jacket A is composed of a jacket A1 on the upstream side and a jacket A2 on the downstream side of the connection mating surface between the exhaust pipe 20 and the expansion chamber 21. The downstream end of the downstream jacket A2 communicates with the elastic joint 22, and the cooling water cools the joint 22 before the exhaust pipe 2
3 through the front portion 23a, the water lock 24, and the rear portion 23b of the exhaust pipe 23 for drainage.

A waste water outlet 21d is formed near the downstream end of the expansion chamber 21.
The waste water hose 28b connected to the outlet 21d extends to a predetermined waste water inspection position.

A main cooling water outlet 14d is formed in the propulsion duct 14 so as to open into the pressure generating chamber B which is a portion downstream of the impeller 16. This outlet 14d is connected by a main water supply hose 27 to an inlet 11a formed so as to communicate with the cylinder bore cooling jacket from the cooling jacket around the common exhaust passage 3a of the cylinder block 11. In addition, the propulsion duct 14 and the exhaust cooling jacket A are provided with an abnormal cooling water outlet 14e and a water supply port 21c, respectively, in the pressure generating chamber B,
It is provided so as to open to the downstream jacket A2. When an abnormal temperature rise of the exhaust system is notified by a warning lamp or the like, the water supply hose (removable water supply passage) 39 separately prepared by the operator or the like is used to connect the pressure generating chamber B of the propulsion unit 4 to the pressure generating chamber B. The downstream jacket A2 is directly connected for communication. The cooling water outlet 14e and the water supply port 21c are normally closed by plugs.

The cylinder bore cooling jacket of the cylinder block 11 communicates from the combustion chamber cooling jacket of the cylinder head 12 to the cooling water outlet 13a of the head cover 13, and the outlet 13a is upstream of the upstream jacket A1 by a cooling hose (not shown). It is connected to the end A1 '.

Further, the main watercraft 1 is provided with a control unit 35, which judges that the exhaust system is overheated when the temperature detected by the thermosensor 36 on the downstream side of the catalyst exceeds a predetermined overheat temperature, and the engine is rotated. The engine speed is set to a predetermined speed (for example, 200
The minimum number of revolutions that can return to the port is 0 to 3000 rpm)
A warning lamp or warning buzzer is used to notify the outside of abnormal temperature rise in the exhaust system. The engine speed is regulated by ignition timing control and throttle opening control.

Next, the function and effect will be described. Main watercraft 1
In the cooling device of No. 2, the pressure generating chamber B is
Water in the cylinder block 1 passes through the main hose 27.
1 is supplied. This supply water is supplied to the upstream end A1 'of the exhaust system cooling jacket A from the cooling jacket around the common exhaust passage and the cylinder jacket, the cooling jacket around the combustion chamber and the head cover 13, and the upstream jacket A1 to the downstream jacket A2. Cooling the elastic joint 2
It is drained from 2 through the exhaust pipe 23.

Then, due to clogging of any of the cooling paths from the propulsion unit 4 to the main hose 27, the engine cooling jacket, the upstream jacket A1 of the exhaust system, and the downstream cooling jacket A2, the downstream side of the downstream jacket A2 is downstream of the catalyst. When the temperature of the part exceeds the overheat temperature and rises, the control unit regulates the engine speed to a predetermined speed or less and turns on a warning lamp. In this case, the pressure generating chamber B of the propulsion unit 4 and the downstream jacket A are provided by a water supply hose (removable water supply passage) 39 separately prepared by the operator or the like.
Directly connect 2 and. As a result, a large amount of seawater is supplied to the downstream cooling jacket A2, and the abnormal temperature rise is eliminated.

As described above, in the main watercraft 1, the catalyst 25
When the temperature of the exhaust system on the downstream side abnormally rises, the water is supplied to the upstream side of the catalyst 25 of the exhaust system cooling jacket A by the water supply hose 39, so that the cooling water path passing through the engine cooling jacket is blocked. Even if there is, abnormal temperature rise in the vicinity of the catalyst and its downstream side can be prevented and damage to the exhaust system can be prevented.

Further, during the period until the above abnormal temperature rise is eliminated, the engine speed is regulated to a predetermined value or less at which it is possible to return to the port, so that it is possible to return to the port and minimize damage to the engine. Further, since the alarm lamp is used to notify the outside, it is possible to know that the abnormal temperature rise state has occurred in the exhaust system.

In the above embodiment, the pressure supply chamber B and the downstream jacket A2 are always connected by the water supply hose 39, and a switching valve is provided in the middle of the water supply hose 39 to activate the above-mentioned notifying means. In that case, the switching valve may be opened.

FIG. 4 is a diagram for explaining a second embodiment according to the invention of claims 1 and 3, and in the figure, the same reference numerals as those in FIG. 3 indicate the same or corresponding portions. In this embodiment, the pressure generating chamber B and the engine cooling jacket are connected to the main hose 27.
And a second cooling system which constantly connects the pressure generating chamber B and the downstream jacket A2 of the exhaust system with a water supply hose 39 '.

When the first and second cooling systems are provided in this way, the exhaust system cooling jacket A is connected to the upstream jacket A1.
And a gasket 26 that defines the downstream jacket A2 and the expansion chamber 21 and the exhaust pipe 2.
The drainage port 20a is provided at the downstream end of the upstream jacket A1 and is connected to the connection surface with 0, and the drainage hose 28a is connected to the drainage port 20a to drain the water of the first cooling system to a predetermined position. It is desirable to configure it.

In this embodiment, since the pressure generating chamber B is directly connected to the downstream jacket A2 of the exhaust system cooling jacket A, the possibility of clogging of the cooling water supply path to the downstream jacket A2 is reduced. It is possible to reliably prevent abnormal temperature rise due to clogging. In the present embodiment, the first
Since the second cooling system is separate and independent, adjustment of the amount of water supplied to each cooling system is easy and reliable.

In the above embodiment, the case of a two-cycle engine has been described, but the present invention can be applied to a four-cycle engine.

[0029]

According to the cooling device of the first aspect of the invention, since the second cooling system for the exhaust system cooling jacket is provided separately from the first cooling system for the engine cooling jacket, for example, cooling is performed. Even if dust etc. is clogged in the cooling path from the water pump to the cylinder bore cooling jacket,
There is an effect that abnormal temperature rise near the expansion chamber of the exhaust system can be prevented and damage to the exhaust system can be avoided.

According to the second aspect of the invention, a detachable water supply passage is provided for communicating the pressure generating chamber of the propulsion unit with the cooling jacket, and informing means for informing the necessity of mounting the water supply passage when the temperature rises abnormally. With the provision of the exhaust system, when the temperature rises abnormally, the ship operator, etc. can connect the pressure generation chamber and the exhaust system cooling jacket through the detachable water supply passage so that the exhaust system can be cooled in the event of an abnormality. There is an effect that damage prevention can be realized at low cost.

According to the third aspect of the present invention, the first cooling system for communicating the pressure generating chamber of the propulsion unit with the engine cooling jacket and the pressure generating chamber with the vicinity of the catalyst in the exhaust system cooling jacket are communicated with each other. With the second cooling system, the exhaust system cooling jacket near the catalyst is directly connected to the propulsion unit that functions as a cooling water pump, reducing the possibility of clogging of the cooling water path to the exhaust system cooling jacket itself. Therefore, there is an effect that the damage due to the abnormal temperature rise of the exhaust system can be prevented without providing a special detection mechanism or the like and without performing a special operation.

[Brief description of drawings]

FIG. 1 is a left side view of a partial cross section of a marine vessel according to a first embodiment of the present invention.

FIG. 2 is a plan view of the above-described water-based traveling ship according to the first embodiment.

FIG. 3 is a cross-sectional right side view of the cooling device of the first embodiment.

FIG. 4 is a sectional right side view of a cooling device according to a second embodiment of the invention of claims 1 and 3.

[Explanation of symbols]

1 Watercraft (ship) 3 engine 4 Propulsion unit (jet propulsion machine) 19 Exhaust system 25 catalyst 27 Main hose (first cooling system) 36 Thermosensor (overheat detection means) 39 Abnormal water supply hose (detachable cooling water passage) 39 'water supply hose (second cooling system) 40 Cooling water supply means A exhaust system cooling jacket A1 upstream jacket A2 Downstream jacket B Pressure generation chamber

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-27707 (JP, A) JP-A-2-256814 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01P 3/20 F01N 3/02

Claims (3)

(57) [Claims] In a cooling device for supplying cooling water to an engine cooling jacket of a marine engine having an exhaust system equipped with a catalyst, water sucked from the bottom of the ship is pressurized and jetted from the stern. A pressure generating chamber of a propulsion unit for generating propulsion force by connecting the engine cooling jacket to the engine cooling jacket, and discharging the cooling water after cooling the engine cooling jacket. A second cooling for connecting the pressure generating chamber and the exhaust system cooling jacket to supply cooling water to the exhaust system cooling jacket, cooling the exhaust system cooling jacket, mixing the cooling water with exhaust gas, and discharging the mixture. A cooling system for a marine engine, which is provided with a system. 2. The removable water supply system according to claim 1, further comprising an overheat detecting means for detecting an overheated state of the exhaust system, wherein the second cooling system communicates between the pressure generating chamber and a cooling jacket of the exhaust system. A cooling device for a marine engine, which is provided with a passage and is provided with an informing means for informing the outside of the necessity of mounting the water supply passage when an overheated state is detected. 3. A cooling device for a marine engine having an exhaust system equipped with a catalyst, wherein cooling water is supplied to an exhaust system cooling jacket through the engine cooling jacket. A first cooling system that connects a pressure generating chamber of a propulsion unit that generates a propulsive force by jetting with an engine cooling jacket, and cools a portion of the exhaust system cooling jacket upstream of the catalyst from the engine cooling jacket; A cooling device for a marine engine, comprising: a second cooling system that communicates the generation chamber with a portion of the exhaust system cooling jacket in the vicinity of the catalyst and cools a downstream side portion of the exhaust system jacket from the vicinity of the catalyst.