CN101560903B - Water-cooled vertical engine and outboard motor equipped therewith - Google Patents

Abstract

The invention provides a water-cooled vertical engine, which comprises: a vertically arranged crankshaft, a camshaft, an engine body and a cover body; an annular transmission part housing chamber formed by connecting the cover body on the upper surface of the engine body; Arranged in the annular transmission part housing chamber, the annular transmission part for transmitting the driving force of the crankshaft to the camshaft; the water cooling jacket formed in the engine body; and the thermostat for controlling the cooling in the water cooling jacket The flow rate of water, the thermostat is arranged in the thermostat mounting seat, and the thermostat mounting seat is formed on the cover at the position above the ring-shaped transmission part; the cooling water channel is used in the water cooling jacket Communication with the thermostat is provided, and the cooling water channel is integrally formed with the cover body.

Description

Water-cooled vertical engine and outboard motor equipped with the water-cooled vertical engine

The present invention is a divisional application of the Chinese invention patent application with the application number 200310100284.3, the application date is October 10, 2003, and the invention title is "water-cooled vertical engine and outboard motor equipped with the water-cooled vertical engine".

technical field

The invention relates to a water-cooled vertical engine having a substantially vertically arranged crankshaft; the invention also relates to an outboard motor equipped with a water-cooled vertical engine.

Background technique

For vertical engines for outboard motors, water-cooled engines are usually used. In a water-cooled engine with an outboard motor disclosed in Japanese Patent Application Laid-Open Publication No. 10-212948, a thermostat for controlling the flow of cooling water in the water-cooling jacket according to the temperature of the cooling water is arranged on the upper part of the engine body , and the timing belt is arranged on the upper part of the engine body, and the camshaft is driven by the crankshaft through the timing belt.

The thermostat thus arranged in the upper part of the engine body can detect the temperature of the cooling water supplied from the bottom end of the water cooling jacket, and perform heat exchange, so that the flow rate of the cooling water can be properly controlled. Also, since the timing belt is arranged on the upper portion of the engine body, assembly and maintenance can be easily performed.

However, in the above structure, since the thermostat is arranged in the cover for covering the upper part of the timing belt, there is a problem that the maintenance of the thermostat requires removal of the cover, so the workability is poor . In order to facilitate the maintenance of the thermostat, it can be considered to arrange the thermostat on the upper surface of the cover used to cover the upper part of the timing belt, but this requires cooling water pipes, which are used in this thermostat A connection is provided between the water cooling jacket arranged in the engine body. This results in an increase in the number of parts and assembly steps.

Moreover, when the thermostat for controlling the cooling water flow rate in the cylinder block cooling jacket and the second thermostat for controlling the cooling water flow rate in the cylinder head cooling water jacket are provided separately, it is necessary to install the two The thermostat is compactly arranged in the limited space above the engine.

Contents of the invention

The present invention takes the above circumstances into consideration, and the first object of the present invention is to provide a water-cooled vertical engine and an outboard motor equipped with the water-cooled vertical engine, wherein the thermostat arranged in the water-cooled jacket of the engine body Repairs can be easily performed.

Moreover, a second object of the present invention is to provide a water-cooled vertical engine and an outboard motor equipped with the water-cooled vertical engine, wherein cooling water can be easily supplied to the thermostat while ensuring that the engine can be easily maintained. thermostat.

Also, a third object of the present invention is to compactly arrange two thermostats in a water-cooled vertical engine or an outboard motor equipped with the water-cooled vertical engine.

In order to achieve the first object of the present invention, the first aspect of the present invention provides a water-cooled vertical engine, which includes: a crankshaft arranged substantially vertically; a camshaft; and an annular transmission member for transferring the driving force of the crankshaft to transmitted to the camshaft, the annular transmission part is arranged on the upper part of the engine so as to rotate along a track; wherein, the engine also includes: a water cooling jacket formed therein, the water cooling jacket has a cooling water outlet, and the cooling water outlet is directed to the engine The upper part is open and located in the rotation track of the annular transmission part; and a thermostat for controlling the flow of cooling water in the water cooling jacket, the thermostat is arranged on the upper part of the engine and has a temperature sensing portion of the component.

According to this structure, since the thermostat for controlling the flow rate of the cooling water in the water jacket of the engine is arranged at the upper part of the engine and higher than the annular transmission member for transmitting the driving force of the crankshaft to the camshaft, therefore, The thermostat is easily accessible from the top of the engine without being obstructed by annular drive members, and the cooling water pipes for draining cooling water from the thermostat are easily accessible.

In order to achieve the first object, according to the second aspect of the present invention, in addition to the first aspect, a water-cooled vertical engine is provided, wherein the endless transmission part is a timing chain, the upper part of the engine is formed by a chain cover, and the chain A cover covers the timing chain, and the chain cover mates with the cylinder head and cylinder block.

According to this structure, since the timing chain is covered by the chain cover fitted with the cylinder head and the cylinder block, and the camshaft is driven by the crankshaft through the timing chain, the timing chain can be well maintained in the lubricating oil environment.

In order to achieve the first object, a third aspect of the present invention provides an outboard motor equipped with a water-cooled vertical engine, which includes: a crankshaft arranged substantially vertically; a camshaft; and an annular transmission member for turning the crankshaft The driving force is transmitted to the camshaft, and the annular transmission part is arranged on the upper part of the engine; wherein, the engine further includes: a water cooling jacket formed therein; a water pump for supplying cooling water to the water cooling jacket; and a thermostat , for controlling the flow of cooling water in the water cooling jacket, the thermostat is arranged on the upper part of the engine and has a temperature sensing part higher than the annular transmission part.

According to this structure, since the thermostat for controlling the flow rate of the cooling water in the water jacket of the engine is arranged at the upper part of the engine and higher than the annular transmission member for transmitting the driving force of the crankshaft to the camshaft, therefore, The thermostat is easily accessible from the top of the engine without being obstructed by annular transmission members, and the cooling water pipes for draining cooling water from the thermostat are easily accessible.

In order to achieve the second purpose, according to a fourth aspect of the present invention, a water-cooled vertical engine is provided, which includes: a crankshaft arranged substantially vertically; a camshaft; an engine body; a cover; an annular transmission component housing chamber, The annular transmission part housing chamber is formed by connecting the cover body on the upper surface of the engine body; the annular transmission part is used to transmit the driving force of the crankshaft to the camshaft, and the annular transmission part is arranged in the annular transmission part housing chamber wherein, the engine also includes: a water cooling jacket formed in the engine body; and a thermostat for controlling the flow of cooling water in the water cooling jacket, and the thermostat is arranged on the thermostat mounting seat Among them, the thermostat mounting seat is formed on the cover at the position above the annular transmission part; the cooling water channel is used to provide communication between the water cooling jacket and the thermostat, and the cooling water channel is connected to the cover The body is formed as a whole.

According to this structure, since the thermostat for controlling the flow rate of the cooling water in the water cooling jacket formed in the engine body is arranged in the cover body, which cooperates with the engine body to form the annular transmission member housing chamber, and The water cooling jacket and the thermostat communicate with each other through the cooling water channel formed in the cover body, therefore, not only can the maintenance of the thermostat be easily carried out from the top of the engine, but also the maintenance of the water cooling jacket and the automatic thermostat can be omitted. A dedicated cooling water pipe is provided between the thermostats.

In order to achieve the second object, according to the fifth aspect of the present invention, in addition to the fourth aspect, there is provided a water-cooled vertical engine, wherein the drain pipe for draining the cooling water from the thermostat is separated from the cover parts are formed.

According to this structure, since the drain pipe for draining the cooling water from the thermostat is formed by a member separate from the cover body, it is easy to handle the cooling water pipe.

In order to achieve the second object, according to a sixth aspect of the present invention, there is provided an outboard motor equipped with a water-cooled vertical engine, which includes: a crankshaft arranged substantially vertically; a camshaft; an engine body; a cover; an annular a transmission part housing chamber, the annular transmission part housing chamber is formed by attaching a cover body on the upper surface of the engine body; an annular transmission part for transmitting the driving force of the crankshaft to the camshaft, the annular transmission part is arranged In the housing chamber of the annular transmission part; Wherein, the engine also includes: a water cooling jacket formed in the engine body; a water pump, used to supply cooling water to the water cooling jacket; and a thermostat, used to control the water cooling jacket The flow rate of the cooling water, the thermostat is arranged in the thermostat mounting seat, and the thermostat mounting seat is formed on the cover at the position above the annular transmission part; the cooling water channel is used for water cooling Communication is provided between the sleeve and the thermostat, and the cooling water channel is integrally formed with the cover.

According to this structure, since the thermostat for controlling the flow rate of the cooling water in the water cooling jacket formed in the engine body is arranged in the cover body, which cooperates with the engine body to form the annular transmission member housing chamber, and The water cooling jacket and the thermostat communicate with each other through the cooling water channel formed in the cover body, therefore, not only can the maintenance of the thermostat be easily carried out from the top of the engine, but also the maintenance of the water cooling jacket and the automatic thermostat can be omitted. A dedicated cooling water pipe is provided between the thermostats.

In order to achieve the third object, according to the seventh aspect of the present invention, there is provided a water-cooled vertical engine, which includes: a crankshaft arranged substantially vertically; a first thermostat for controlling The flow rate of cooling water in the cylinder block cooling water jacket; and the second thermostat for controlling the flow rate of cooling water in the cylinder head cooling water jacket formed in the cylinder head; wherein, with the first thermostat The cylinder block cooling water jacket cooling water outlet connected to the thermostat and the cylinder head cooling water jacket cooling water outlet connected to the second thermostat are close to each other, and the parts used to form the thermostat chamber are connected with two cooling water The outlet cylinder block is connected to the cylinder head, and the thermostat chamber houses the first and second thermostats.

According to this structure, since the member for forming the thermostat chamber is connected to the cylinder block and the cylinder head so as to cover the cylinder block cooling water jacket cooling water outlet and the cylinder head cooling water jacket cooling water outlet arranged close to each other, the thermostat The thermostat chamber is equipped with a first thermostat for controlling the flow of cooling water in the cylinder block cooling jacket and a second thermostat for controlling the flow of cooling water in the cylinder head cooling jacket, so the first The first and second thermostats can be arranged compactly, reducing the installation space.

In order to achieve the third object, according to the eighth aspect of the present invention, in addition to the seventh aspect, there is provided a water-cooled vertical engine, wherein an annular transmission part for transmitting the driving force of the crankshaft to the camshaft is arranged on the engine body The upper part of the first and second thermostats are arranged inside the ring transmission part.

According to this structure, since the thermostat is arranged inside the ring-shaped transmission part for transmitting the driving force of the crankshaft to the camshaft and at the upper part of the engine body, the space inside the ring-shaped transmission part can be Effective for compactly arranging the first and second thermostats.

In order to achieve the third aspect, according to the ninth aspect of the present invention, in addition to the seventh aspect, there is provided a water-cooled vertical engine, the crankshaft, and the first and second thermostats have a common cooling water drainage part.

According to this structure, since the common cooling water drain member is used for the first and second thermostats, the number of pipes for draining cooling water can be reduced to one, thereby reducing the number of parts.

In order to achieve the third object, according to the tenth aspect of the present invention, there is provided an outboard motor equipped with a water-cooled vertical engine, which includes: a crankshaft arranged substantially vertically; a first thermostat for controlling A flow rate of cooling water in a cylinder block cooling water jacket formed in the cylinder block; and a second thermostat for controlling a flow rate of cooling water in a cylinder head cooling water jacket formed in the cylinder head; wherein , the cylinder block cooling water jacket cooling water outlet connected to the first thermostat and the cylinder head cooling water jacket cooling water outlet connected to the second thermostat are close to each other and are used to form parts of the thermostat chamber Connected to the cylinder block and cylinder head with two cooling water outlets, the thermostat chamber houses the first and second thermostats.

According to this structure, since the member for forming the thermostat chamber is connected to the cylinder block and the cylinder head so as to cover the cylinder block cooling water jacket cooling water outlet and the cylinder head cooling water jacket cooling water outlet arranged close to each other, the thermostat The thermostat chamber is equipped with a first thermostat for controlling the flow of cooling water in the cylinder block cooling jacket and a second thermostat for controlling the flow of cooling water in the cylinder head cooling jacket, so the first The first and second thermostats can be arranged compactly, reducing the installation space.

The cylinder block 11 and the cylinder head 15 of the embodiment correspond to the engine body of the present invention, the cooling water channels 11i and 15a of the embodiment correspond to the cooling water outlet of the present invention, and the timing chain 30 of the embodiment corresponds to the endless transmission of the present invention Parts, the chain cover 31 of the embodiment corresponds to the cover body of the present invention or a part for forming a thermostat chamber, and the first and second thermostats 84 and 85 of the embodiment correspond to the thermostat of the present invention , The cylinder block cooling water jacket JB and the cylinder head cooling water jacket JH of the embodiment correspond to the water cooling jacket of the present invention, and the pipe joint 87a of the embodiment corresponds to the cooling water drainage part of the present invention. Also, the chain cover 31 of the embodiment forms a part of the engine E. As shown in FIG.

The above objects, other objects, features and advantages of the present invention will be apparent from the description of preferred embodiments, which will be described in detail below with reference to the accompanying drawings.

Description of drawings

1 to 19 show an embodiment of the present invention.

Figure 1 is a general side view of the outboard motor.

FIG. 2 is an enlarged cross-sectional view along line 2-2 in FIG. 1 .

FIG. 3 is an enlarged cross-sectional view along line 3-3 in FIG. 2 .

FIG. 4 is an enlarged view along arrow 4 in FIG. 2 .

FIG. 5 is a view along arrow 5 in FIG. 4 .

Fig. 6 is an enlarged sectional view of a main part in Fig. 1 .

Fig. 7 is an enlarged view along line 7-7 in Fig. 1 (a top view of the mounting case).

Figure 8 is an enlarged view along line 8-8 in Figure 1 (bottom view of the pump body).

Fig. 9 is an enlarged view along line 9-9 in Fig. 1 (bottom view of sub-assemblies of the cylinder block, etc.).

Fig. 10 is an enlarged view of an exhaust manifold.

Fig. 11 is an enlarged view of the connection between the exhaust manifold and the exhaust guide.

Fig. 12 is a view along arrow line 12-12 in Fig. 11 (plan view of the exhaust guide).

Fig. 13 is a cross-sectional view along line 13-13 in Fig. 11 .

FIG. 14 is an enlarged view along arrow line 14-14 in FIG. 1 .

FIG. 15 is an enlarged view along arrow line 15-15 in FIG. 1 .

FIG. 16 is an enlarged cross-sectional view along line 16-16 in FIG. 15 .

FIG. 17 is an enlarged cross-sectional view along line 17-17 in FIG. 16. FIG.

FIG. 18 is a cross-sectional view along line 18-18 in FIG. 16 .

Figure 19 is a circuit diagram of the engine cooling system.

Detailed ways

As shown in FIGS. 1 to 3, the outboard motor O is mounted on the hull so that it can perform steering motions around a steering shaft 96 in left and right directions, and can perform tilting motions around a tilting shaft 97 in a vertical direction. The in-line four-cylinder four-stroke water-cooled vertical engine E installed on the top of the outboard motor O comprises: a cylinder block 11; a base (lower block) 12, which is connected to the front surface of the cylinder block 11; a crankshaft 13, which is Arranged in a substantially vertical direction and supported so that the journal 13a remains between the cylinder block 11 and the base 12; the crankcase 14 is connected to the front surface of the base 12; the cylinder head 15 is connected to the cylinder head 15 The rear surface of the cylinder block 11 is attached; and the end cover 16 is attached to the rear surface of the cylinder head 15 . Four cylinders 17 in the form of sleeves are cast around the cylinder block 11 , and pistons 18 are slidably installed in the cylinders 17 and connected to the crank pin 13 b of the crankshaft 13 through connecting rods 19 .

A combustion chamber 20 is formed in the cylinder head 15 so as to face the top surface of the piston 18, and the combustion chamber is connected to an intake manifold 22 through an intake port 21 and to an engine compartment exhaust passage 24 through an exhaust port 23. , the suction port 21 opens on the left-hand side surface of the cylinder head 15, that is, opens on the left side of the ship when facing the running direction, and the exhaust port 23 opens on the right-hand side of the cylinder head 15. The suction valve 25 for opening and closing the downstream end of the suction port 21 and the exhaust valve 26 for opening and closing the upstream end of the exhaust port 23 are made such that the DOHC type valve installed in the end cover 16 Operating mechanism 27 to open and close. The upstream side of the suction manifold 22 is connected to a throttle valve 29 arranged at the front of the crankcase 14 and fixed on the front surface of the crankcase, and the suction air is supplied to the Suction manifold 22. An injector base 57 in which an injector 58 for injecting fuel into the intake port 21 is arranged is held between the cylinder head 15 and the intake manifold 22 .

The chain cover 31 is connected to the upper surface of the cylinder block 11, the base 12, the crankcase 14 and the cylinder head 15 of the engine E (see FIG. 15), and the chain cover 31 is equipped with a timing chain 30 (see FIG. 14) for The driving force of the crankshaft 13 is transmitted to the valve operating mechanism 27 . The lubricating oil pump body 34 is connected to the bottom surfaces of the cylinder block 11 , the base 12 and the crankcase 14 . The installation housing 35 , the lubricating oil tank 36 , the extension housing 37 and the gear box 38 are sequentially connected to the bottom surface of the lubricating oil pump body 34 .

The lubricating oil pump body 34 has a lubricating oil pump 33 installed between the bottom surface of the lubricating oil pump body 34 and the upper surface of the mounting case 35, and the lubricating oil pump body 34 has a flywheel 32 etc. on the opposite side, and the flywheel 32 Arranged between this lubricating oil pump body 34 and the bottom surface of the cylinder block 11 . The lubricating oil pump body 34 defines the flywheel chamber and the lubricating oil pump chamber. The oil tank 36, the mounting case 35 and the bottom side surrounding parts of the engine E are all covered with a synthetic resin bottom cover 39, and the upper part of the engine E is covered with a synthetic resin engine cover 40 connected to the upper surface of the bottom cover 39.

The drive shaft 41 is connected to the bottom end of the crankshaft 13, extends through the pump body 34, the mounting housing 35 and the lubricating oil tank 36, and extends downwards into the extension housing 37, and is connected with the forward/backward operation conversion mechanism 45. The front end of the propeller shaft 44 having the propeller 43 at its rear end and supported by the gear box 38 in the longitudinal direction is connected, and the forward/reverse running switching mechanism 45 is operated by a switching lever 52 . The cooling water pump 46 is arranged on the drive shaft 41 and is connected to a bottom water supply passage 48 extending upward from a filter arranged in the gear case 38 . The upper water supply pipe 49 extends upward from the cooling water pump 46 and is connected to the cooling water passage 36b (see FIG. 6 ) arranged in the lubricating oil tank 36 .

As shown in FIG. 6 , a cooling water supply hole 36 a is formed in a bottom surface 36L of the oil tank 36 and is connected to an upper end of an upper water supply pipe 49 . A cooling water passage 36b communicating with this cooling water supply hole 36a is formed in the upper surface 36U of the oil tank 36 so as to surround a part of the exhaust pipe portion 36c integrally formed with the oil tank 36 . The cooling water passage 35a is formed around a part of the exhaust passage 35b extending through the mounting case 35, and the cooling water passage 35a has the same shape as the cooling water passage 36b in the upper surface 36U of the oil tank 36. The upper surface 36U of the oil tank 36 is connected to the bottom surface 35L of the mounting case 35 .

FIG. 7 is a view of the mounting case 35 as seen from above. An oil tank 36 is connected to the bottom surface of the mounting case 35 . The outer periphery of the exhaust passage 35b is surrounded by a cooling water supply passage 35c and a cooling water discharge passage 35d. In detail, the cooling water passage 35a is formed to open downward on the bottom surface 35L of the mounting case 35, and the cooling water supply passage 35c (see FIG. 6 ) communicating with the cooling water passage 35a is formed to open upward to the mounting case. On the upper surface 35U of the body 35 and in a region outside the cylinder block mounting surface, and extend along the outer periphery of the cylindrical exhaust passage 35b. In this embodiment, there are three cooling water supply passages 35c which are arcuate and separated from each other by a wall 35h connected to the outer wall of the exhaust passage 35b. Also, an arc-shaped cooling water discharge passage 35d formed by forming the cooling water supply passage 35c is formed in the outer region of the region where the cooling water supply passage 35c is arranged around the outer periphery of the cylindrical exhaust passage 35b. Determined by the wall 35i of the outer wall.

The cooling water supply passage 35e is formed in the upper surface 35U of the mounting case 35, and is in the shape of a channel having a U-shaped cross-section. Extending left and right so as to bridge the center of the cylinder 17 in plan view (see FIG. 6 ), the upper surface 35U of the mounting housing 35 is connected to the cylinder block subassembly containing the lubricating oil pump body 34 , which will be described later. The above-mentioned cooling water passage 35a extends upward and communicates with the cooling water passage 35e. On the upper surface 35U of the mounting case 35 is provided a release valve 51 which is opened to release cooling water when the pressure of the cooling water passage 35a reaches a predetermined value or higher (see FIGS. 4 and 7 ).

The cooling water discharge passage 35d communicates with the exhaust chamber 63 formed in the oil tank 36, the extension case 37, through the opening 36e (see FIG. and gearbox 38. The gasket is sandwiched between the bottom surface 35L of the mounting case 35 and the upper surface 36U of the oil tank 36 . A punching hole 55a and a punching hole 55b are provided in the gasket 55, and the cooling water dripping from the cooling water discharge channel 35d (see FIG. 7) of the mounting case 35 will pass through the punching hole 55a, while the punching hole 55b defines the exhaust gas. Part of the chamber 63, and has a sound-absorbing effect (see Figures 6 and 7).

The structure of the engine compartment exhaust passage 24 will be described below with reference to FIGS. 4 to 6 and FIGS. 10 to 13 .

The exhaust duct arrangement is roughly divided into a nacelle exhaust duct 24 section and an exhaust chamber section separate from the nacelle. The engine compartment exhaust passage 24 is connected to the right side of the cylinder head 15, as described below, and includes an exhaust manifold 61 and an exhaust guide 62 connected to the exhaust manifold 61, And direct the exhaust gases away from the engine nacelle. The exhaust manifold 61 includes: a single-pipe portion 61a for guiding exhaust gas from each combustion chamber 20; and a combined portion 61b in a downstream region of these single-pipe portions 61a.

As best seen in FIG. 6 , the exhaust guide 62 is connected to the upper surface 35U of the mounting housing 35 , which forms the nacelle partition, and communicates with the exhaust passage 35 b extending through the mounting housing 35 . The exhaust passage 35 b communicates with an exhaust pipe portion 36 c integrally formed with the oil tank 36 and communicates with the exhaust chamber 63 . In the present embodiment, the oil tank 36 forms the outer wall portion of the exhaust chamber 63 and also forms the exhaust duct portion 36c, while in another structure, the exhaust duct portion 36c may be formed as a separate passage. The exhaust duct arrangement may be arranged such that its components are joined in one piece, but it is also possible to have the nacelle exhaust duct 24 formed separately from its outer passages, making assembly of the parts easier and maintaining the sealing characteristics of the exhaust chamber 63 .

The upper part of the exhaust chamber 63 communicates with the outside of the bottom cover 39 through the exhaust outlet pipe 64 arranged in the oil tank 36, so that when the engine E operates at a low load, exhaust gas is discharged to the into the atmosphere, not into the water.

The exhaust manifold 61 has: four single-pipe portions 61a connected to the four exhaust ports 23; and a combined portion 61b at which the single-pipe portions 61a are combined together . Most of the combined portion 61b is in close contact with the side surface of the cylinder head 15, but is bent near the bottom end portion of the combined portion 61b so that its center line is separated from the side surface of the cylinder head 15 by a distance α (see FIG. 10). The exhaust guide 62 is bent in an S shape, and the outer circumference of the bottom end of the exhaust manifold 61 is fitted into the inner circumference of the larger-diameter connection portion 62a at the upper end of the exhaust guide 62 through a pair of O-rings 53 and 54 .

Thus, only the vicinity of the bottom end portion of the exhaust manifold 61 is bent away from the side surface of the cylinder head 15 , while the remaining upper half of the exhaust manifold 61 is connected along the side surface of the cylinder head 15 . Therefore, it is possible to prevent the larger-diameter connecting portion 62a from interfering with the cylinder head 15 while minimizing the space for arranging the nacelle exhaust passage 24 . In particular, since the bent portion of the exhaust manifold 61 is lower than the lowest combustion chamber 20, an unbalanced effect on the flow of exhaust gas from a plurality of combustion chambers 20 arranged in the vertical direction can be prevented, thereby improving exhaust efficiency. reduce to a minimum.

Moreover, since the connecting portion 62a of the exhaust manifold 61 and the exhaust guide 62 has such a structure that they are fitted together through the O-rings 53 and 54, it is possible not only to connect the exhaust manifold 61 and the exhaust The guide 62 is easy to operate, and the dimensional error of the engine compartment exhaust passage 24 in the vertical direction can be absorbed by the connecting portion 62a, thereby making assembly easier. Also, since the upper end portion of the first exhaust guide cooling jacket JM1 and the bottom end portion of the exhaust manifold cooling jacket JM2 are arranged near the O-rings 53 and 54, it is possible to prevent the O-rings 53 and 54 from being damaged due to heat. and damaged.

The exhaust guide 62 has a flange 62b formed at its bottom end. Three bolt holes 62c, three cooling water inlets 62e and one cooling water outlet 62f are formed in the flange, and the three cooling water inlets 62e are arc-shaped and surround the exhaust passage 62d. When the flange 62b of the exhaust guide 62 is bolted to the mounting seat 35f (see FIG. 7 ) on the upper surface 35U of the installation housing 35, the cooling water inlet 62e of the exhaust guide 62 is connected to the mounting housing 35. The cooling water supply passage 35c communicates, and the cooling water outlet 62f communicates with the cooling water discharge passage 35d of the mounting case 35 . With respect to the bottom surface 35L of the mounting seat 35f of the mounting case 35, in the outer wall forming the cooling water discharge passage 35d, the side portion opposite to the discharge passage 35b is held at a slightly higher position than the gasket surface, and the cooling water passes through the outer wall. The gap between the bottom surface and the gasket surface is drained onto the gasket 55.

A first exhaust guide cooling water jacket JM1 and a second exhaust guide cooling water jacket JM3 surrounding the exhaust passage 62 d are formed in the exhaust guide 62 . The first exhaust guide cooling water jacket JM1 covers half of the outer circumference on the upper surface side, and the second exhaust guide cooling water jacket JM3 covers half of the outer circumference on the bottom surface side. A portion of the first exhaust guide cooling water jacket JM1 in the circumferential direction protrudes at the upper end portion of the exhaust guide 62 so as to form a protruding portion 62g.

The exhaust manifold cooling jacket JM2 is formed to surround the exhaust manifold 61, and a through hole 61c extending in the circumferential direction is formed at the bottom end of the exhaust manifold cooling jacket JM2. Therefore, when the bottom end of the exhaust manifold 61 fits into the inner peripheral portion of the connecting portion 62a of the exhaust guide 62, the exhaust manifold cooling jacket JM2 of the exhaust manifold 61 and the exhaust guide 62 The first exhaust guide cooling jacket JM1 communicates with each other through the through hole 61c of the exhaust manifold 61 and the protruding portion 62g of the exhaust guide 62 (see FIG. 13 ).

As clearly shown in FIGS. 4 and 5 , in the upper part of the exhaust manifold cooling water jacket JM2, there are pipe joints 61d for distributing part of the cooling water to the cylinder block 11, and for supplying part of the cooling water to the cylinder block 11 through a hose 65. A pipe joint 61e of a water check outlet 66 (see FIG. 2 ) and a cooling water temperature sensor 67 for detecting the temperature of the cooling water.

Next, the structure of the cooling water system of the cylinder block 11 will be described with reference to FIGS. 3 to 5 .

The cooling water cools the engine compartment exhaust passage 24 while passing through the first exhaust guide cooling water jacket JM1 of the exhaust guide 62 and the exhaust manifold cooling water jacket JM2 of the exhaust manifold 61, after which its temperature rises, The cooling water is supplied to the T-shaped tee joint or branch member 69 through the water supply pipe 68 from the pipe joint 61d arranged at the upper end of the exhaust manifold cooling water jacket JM2 of the exhaust manifold 61, and branched to two water supply pipes 70 and within 71. A cylinder block cooling jacket JB surrounding four cylinders 17 is formed in the cylinder block 11 . The pipe joints 11a and 11b are arranged near the upper end of the cylinder block cooling water jacket JB (on the side of the second tallest combustion chamber 20) and near the bottom end of the cylinder block cooling water jacket JB (on the side of the lowest combustion chamber 20 the side). The water supply pipe 70 on the upper side is connected to the pipe connection 11 a on the upper side, and the water supply pipe 71 on the bottom side is connected to the pipe connection 11 b on the bottom side. Thus, since the exhaust manifold cooling jacket JM2 and the cylinder block cooling jacket JB are connected through the water supply pipes 68, 70, and 71, compared with the case where the cooling water supply passages are formed in the cylinder block 11 and the cylinder head 15, mechanical Processing is easier.

A slot-shaped cooling water passage 34a (see FIG. 8 ) formed to extend through the pump body 34 communicates with a slot-shaped cooling water passage 35e (see FIG. 7 ) formed to extend through the mounting case 35, and the cooling water passage 34a Also communicates with the cooling water passage 11c (see FIG. 9 ) formed in the bottom surface of the cylinder block 11, which has the same mating surface shape as the cooling water passage 35e, and extends in the left-right direction so as to bridge the cylinder 17 In the middle along the left-right width direction. As shown in FIGS. 3 and 9, the cooling water passage 11c of the cylinder block 11 has a downwardly open channel shape, and is connected to the cylinder block 11 through two through holes 11d and 11e extending through the upper wall of the channel. The bottom end of the cylinder block cooling water jacket JB is connected.

As clearly shown in FIG. 3, after flowing through the cylinder block cooling water jacket JB of the cylinder block 11, the cooling water is supplied to a thermostat described later through a cooling water passage 11f formed in the upper left portion of the cylinder block 11. .

The structure of the cooling system of the cylinder head 15 will be described below with reference to FIGS. 3 , 6 and 9 .

Two short cooling water passages 11 g and 11 h branch toward the cylinder head 15 from the side wall of the slot-shaped cooling water passage 11 c formed in the bottom surface of the cylinder block 11 . These cooling water passages 11 g and 11 h communicate with the cylinder head cooling water jacket JH of the cylinder head 15 through the gasket 56 arranged between the cylinder block 11 and the cylinder head 15 . The cylinder block cooling jacket JB surrounding the cylinders 17 of the cylinder block 11 is isolated from the cylinder head cooling jacket JH of the cylinder head 15 by a gasket 56 arranged between the mating surfaces of the cylinder block 11 and the cylinder head 15 (see FIGS. 2 and 15 ). 6).

The thermostat arranged in the cooling water circulation system will be described below.

As shown in FIG. 14 , the timing chain 30 is wound around a cam drive sprocket 72 disposed at the upper end of the crankshaft 13 and around a cam follower sprocket 75 disposed at the rear of the cylinder head 15 . On a pair of camshafts 73 and 74. The hydraulic chain tensioner 76a abuts against the slack side of the timing chain 30 and the chain guide 76b abuts against the opposite side of the timing chain 30 . The cam drive sprocket 72 has half the number of teeth of the cam follower sprocket 75 , and therefore, the rotational speed of the camshafts 73 and 74 is half that of the crankshaft 13 .

The balancer 77 is installed in the crank case 14 . The endless chain 82 is wound on the balancer driving sprocket 81 arranged on the crankshaft 13 and on the balancer driven sprocket 80 arranged on the two balancer shafts 78 of the balancer 77 and one of 79. The chain tensioner 83a abuts against the slack side of the endless chain 82 and the chain guide 83b abuts against the opposite side of the endless chain 82 . The number of teeth of the balancer drive sprocket 81 is twice that of the balancer driven sprocket 80 , and therefore, the rotational speed of the balancer shafts 78 and 79 is twice that of the crankshaft 13 .

As clearly shown in FIGS. 15 to 18, the upper surfaces of the cylinder block 11 and the cylinder head 15 are covered by a chain cover 31 in which the timing chain 30 is housed. In order to lubricate the timing chain 30 , an oil environment is maintained inside the chain cover 31 . A thermostat mount 31 a is formed on the chain cover 31 so as to bridge the mating surfaces of the cylinder block 11 and the cylinder head 15 . The bottom surface of the thermostat mount 31 a abuts against the upper surfaces of the cylinder block 11 and the cylinder head 15 , and the upper surface is stepped higher than the upper surface of the main body portion of the chain cover 31 . An engine rotation speed sensor 59 for detecting the rotation speed of the crankshaft 13 is arranged on the chain cover 31 (see FIG. 15 ).

Cooling water passages 31b and 31c and cooling water passages 31d and 31e that branch upward from the cylinder block cooling jacket JB of the cylinder block 11 are formed in the thermostat mount 31a of the chain cover 31. The cooling water passage 11f communicates, and the cooling water passages 31d and 31e communicate with the cooling water passage 15a branched from the cylinder head cooling jacket JH of the cylinder head 15 . The first thermostat 84 on the cylinder block 11 side is installed in the cooling water passage 31c, and the second thermostat 85 on the cylinder head 15 side is installed in the cooling water passage 31e. The first thermostat 84 with valve body 84a and the second thermostat 85 with valve body 85a are installed in thermostat chambers 94 and 95 respectively, and are fixed on the thermostat chamber by three bolts 86. common thermostat cover 87 on the upper surface of thermostat mount 31a. The pipe joint 87a arranged on the thermostat cover 87 is connected to the second exhaust guide cooling water jacket JM3 through the drain pipe 88 and the pipe joint 62h arranged on the exhaust guide 62 .

The cooling water temperature sensor 89 is arranged in the cooling water passage 31e of the chain cover 31, which faces the second thermostat on the side of the cylinder head cooling water jacket JH.

As mentioned above, the gas in the combustion chamber 20 is cut off by the intake valve 25, the exhaust valve 26 is the first heat source, the exhaust gas flowing to the outside through the engine compartment exhaust passage 24 is the second heat source, and the cylinder head cooling water jacket JH and the cylinder block cooling jacket JB correspond to the first cooling means for cooling the first heat source, while the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 correspond to the second cooling means, which The second heat source is cooled after exchanging heat with the first cooling device.

The structure of the lubricating system of the engine E will be described below with reference to FIGS. 3 , 4 and 6 to 9 .

The oil tank 36 is provided with an integrated oil pan 36d in which a suction pipe 92 having an oil strainer 91 is installed. In the oil pump 33, an oil suction passage 33a, an oil discharge passage 33b, and an oil release passage 33c are provided. The lubricating oil suction passage 33 a is connected to a suction pipe 92 . The oil discharge passage 33b is connected to various parts of the engine E to be lubricated through an oil supply hole 11m (see FIG. 9 ) formed in the bottom surface of the cylinder block 11 . The oil release passage 33c discharges the oil returned from the oil pump 33 into the oil pan 36d.

A part of lubricating oil returns from the valve operating mechanism 27 arranged in the cylinder head 15 and the end cover 16 , and this part of lubricating oil extends through the pipe joint 16 a arranged on the end cover 16 , the lubricating oil hose 93 and through the installation housing 35 The lubricating oil returns to the channel 35g (see Figure 7) and returns to the lubricating oil pan 36d. Another part of the lubricating oil returned from the valve operating mechanism 27 passes through the lubricating oil return passage 15b (see FIG. 9 ) formed in the cylinder head 15, the lubricating oil return passage 11j ( 9), an oil return passage 11k extending through the cylinder block 11 (see FIG. 9), an oil return passage 34b extending through the pump body 34 (see FIG. The oil returns to passage 35g (see FIG. 7) and returns to oil pan 36d. The lubricating oil return passage 11j opens on the surface of the gasket between the cylinder block 11 and the cylinder head 15, and the lubricating oil return passage 11j is arranged between the two cooling water passages 11g and 11h opened on the gasket 56 (see FIG. 3 ) .

Oil returning from the crankcase 14 returns to the oil pan 36d through an oil return passage (not shown) extending through the pump body 34 and through an oil return passage 35g (see FIG. 7 ) extending through the mounting housing 35 .

The operation of the embodiment of the present invention having the above structure will be described below mainly with reference to the cooling water circuit shown in FIG.

When the drive shaft 41 connected to the crankshaft 13 rotates according to the operation of the engine E, the cooling water pump 46 arranged on the drive shaft 41 operates to supply cooling water which is sucked up through the strainer 47 and supplied through the bottom The passage 48 and the upper water supply passage 49 lead to the cooling water supply hole 36 a on the bottom surface of the lubricating oil tank 36 . The cooling water passing through the cooling water supply hole 36a flows into the cooling water passage 36b in the upper surface 36U of the oil tank 36 and the cooling water passage 35a in the bottom surface 35L of the mounting case 35 . A part of the cooling water thus branched is supplied to the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 formed in the exhaust manifold 61, the first exhaust guide cooling water jacket JM1 forming In the exhaust guide 62 of the engine compartment exhaust duct 24 . The exhaust gas discharged from the combustion chamber 20 of the cylinder head 15 passes through the single-pipe portion 61a and combined portion 61b of the exhaust manifold 61, the exhaust passage 62d of the exhaust guide 62, the exhaust passage 35b of the mounting case 35, and the slide The exhaust pipe portion 36c of the oil tank 36 is discharged into the exhaust chamber 63 . The engine compartment exhaust passage 24, which is heated by the exhaust gas during this process, is heated by the cooling water flowing through the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2. to cool off.

The temperature of the cooling water slightly increases after flowing upward through the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 , and the cooling water passes through the water supply pipe 68 and the branch member 69 from the exhaust manifold 61 The pipe joint 61d at the upper end branches into the flow-through water supply pipes 70 and 71, and flows into the bottom and upper part of the side surface of the block cooling water jacket JB through the pipe joints 11a and 11b arranged on the cylinder block 11. During this process, part of the low-temperature cooling water in the cooling water channels 36b, 35a flows into the bottom end of the cylinder block cooling water jacket JB through the two through holes 11d, 11e, which are opened in the cylinder block 11 In the cooling water channel 11c at the bottom. Also, part of the low-temperature cooling water of the cooling water passages 36b, 35a flows into the bottom end of the cylinder head cooling water jacket JH from the cooling water passage 11c at the bottom end of the cylinder block 11 through the two cooling water passages 11g, 11h.

When the engine E is warming up, the first thermostat 84 connected to the upper end of the cylinder block cooling water jacket JB and the second thermostat 85 connected to the upper end of the cylinder head cooling water jacket JH are all closed, The cooling water in the exhaust guide cooling water jacket JM1 , the exhaust manifold cooling water jacket JM2 , the cylinder block cooling water jacket JB and the cylinder head cooling water jacket JH is kept stagnant, thereby promoting the warming up of the engine E. At this time, the cooling water pump 46 continues to rotate, but since the cooling water leaks from around the rubber impeller of the cooling water pump 46, the cooling water pump 46 runs almost idly.

When the engine E is warmed up and the temperature of the cooling water rises, the first and second thermostats 84 and 85 are opened, and the cooling water in the cylinder block cooling water jacket JB and the cooling water in the cylinder head cooling water jacket JH Cooling water flows into the second exhaust guide cooling water jacket JM3 from the common pipe joint 87a of the thermostat cover 87 through the drain pipe 88 and the pipe joint 62h of the exhaust guide 62 . The cooling water cools the exhaust guide 62 when flowing through the second exhaust guide cooling water jacket JM3 , and is discharged into the exhaust chamber 63 after passing through the installation housing 35 and the lubricating oil tank 36 from top to bottom. When the rotational speed of the engine E increases and the internal pressure of the cooling water passages 36b and 35a reaches a predetermined value or higher, the release valve 51 is opened, and excess cooling water is discharged into the discharge chamber 63 .

The pipe joint 61e is arranged on the upper end of the exhaust manifold cooling water jacket JM2 of the exhaust manifold 61. The pipe joint 61e is connected to the water inspection outlet 66 through the hose 65, and the cooling water circulation can be achieved by spraying water from the water inspection outlet 66. to guarantee. Since the pipe joint 61e connected to the water check outlet 66 is arranged at the upper end of the exhaust manifold cooling jacket JM2, the air existing in the exhaust manifold cooling jacket JM2 can be discharged from the water check outlet 66 together with the cooling water. In this way, since the air in the exhaust manifold cooling water jacket JM2 is exhausted using the water check outlet 66, there is no need to provide a dedicated pipe or a dedicated air outlet for exhausting the air, thereby contributing to reducing the number of parts and the number of assembly steps .

Moreover, since the exhaust manifold 61 and the water inspection outlet 66 are arranged on the left and right sides of the outboard motor O, even if the water inspection outlet 66 is arranged lower than the exhaust manifold 61, the exhaust manifold 61 and the water inspection outlet 66 The increase of the distance between them can reduce the descending slope, thereby smoothly pushing the air in the exhaust manifold 61 to the water inspection outlet 66 .

In this embodiment, the exhaust manifold cooling water jacket JM2 communicates with the cylinder block cooling water jacket JB, and flows through the first exhaust guide cooling water jacket JM1, the exhaust manifold cooling water jacket JM2 and the cylinder block cooling water The flow of the cooling water of the jacket JB is controlled by the first thermostat 84 . When the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 are not in communication with the cylinder block cooling water jacket JB, but are closed ends, it will be necessary to increase the diameter of the water inspection outlet 66 in order to All cooling water from the exhaust manifold cooling water jacket JM2 is drained, or a cooling water outlet is provided in addition to the water check outlet 66 to drain the cooling water, but this will generate an increased cooling water flow rate and an increased load on the cooling water pump 46 The problem. However, according to the present embodiment, since the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 communicate with the cylinder block cooling water jacket JB, there is no need to wastefully divert the exhaust air flowing through the first exhaust guide. The cooling water of the cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 is discharged, thereby reducing the load of the cooling water pump 46 .

Moreover, the cylinder block cooling water jacket JB and the cylinder head cooling water jacket JH are independent of each other; the low-temperature cooling water is directly supplied to the cylinder head cooling water jacket JH which is prone to overheating during the operation of the engine E; The cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2 are then heated up, and the cooling water is supplied to the cylinder block cooling water jacket JB, which is prone to overcooling during the operation of the engine E. Therefore, the cylinder head 15 and the cylinder block 11 can be cooled to their proper temperatures in order to optimize the performance of the engine E. As shown in FIG. Moreover, since the thermostats 84 and 85 are arranged in the cylinder block cooling jacket JB and the cylinder head cooling jacket JH, respectively, changing the settings of the thermostats 84 and 85 alone can affect the cylinder block cooling jacket JB and the cylinder head cooling jacket JH. The temperature of the cooling water in the cylinder head cooling water jacket JH is suitably independently controlled.

When the cooling water supplied from the bottom end of the vertically extending cylinder block cooling water jacket JB is discharged from its upper end, the temperature of the cooling water will be lower at the bottom and higher at the upper part, which may cause the cylinder block cooling water jacket JB The cooling performance is not uniform along the vertical direction. However, according to the present embodiment, the cooling water flowing from the exhaust manifold cooling jacket JM2 is supplied to the cylinder block cooling jacket JB at two positions separated from each other in the vertical direction, and therefore, the cooling performance of the cylinder block cooling jacket JB can be uniform in the vertical direction.

Even when fresh cooling water is supplied as the engine speed increases rapidly, after the cooling water increases in temperature while passing through the first exhaust guide cooling water jacket JM1 and the exhaust manifold cooling water jacket JM2, the cooling water is supplied to Cylinder block cooling water jacket JB. Therefore, rapid changes in temperature around the combustion chamber 20 can be reduced.

Also, supplying the supplementary cooling water to the bottom end of the block cooling water jacket JB through the two through holes 11d, 11e will prevent the cooling water from staying in the block cooling water jacket JB and further promote uniform cooling performance. Also, since the through holes 11d, 11e are arranged at the bottom end of the cylinder block cooling water jacket JB, it is easy to dispose of the water remaining when the engine is stopped.

Moreover, since the supply of cooling water from the cooling water passages 36b and 35a to the cylinder head cooling water jacket JH is not performed through the external pipe, but through the cooling water passages 11g and 11h formed in the cylinder block 11 and between the cylinder block 11 and The gasket 56 between the cylinder heads 15, therefore, not only does not need to specially assemble the cooling water passages 11g and 11h, but also the number of parts can be reduced by omitting the external pipe. Also, since the cooling water passages 11g and 11h can be sealed by using the gasket 56 sandwiched between the cylinder block 11 and the cylinder head 15, dedicated seals are not required, thereby reducing the number of parts. Also, since the cooling water passages 11g and 11h are arranged at the bottom end of the cylinder head cooling water jacket JH, it is easy to dispose of the water remaining when the engine is stopped.

In particular, since the two cooling water passages 11g and 11h for supplying cooling water from the cylinder block cooling water jacket JB to the cylinder head cooling water jacket JH are arranged to be divided in the right and left direction, the cooling water can be uniformly supplied to the cylinders Cover the left and right sides of the cooling water jacket JH, thereby improving the cooling effect. Also, since the oil return passage 11j for guiding the return oil from the cylinder head 15 is arranged between the two cooling water passages 11g and 11h, the cooling water passages 11g and 11h arranged at the bottommost part of the cam chamber and the sliding The oil return passage 11j can be compactly arranged in a limited space while preventing flow imbalance of cooling water flowing through the two cooling water passages 11g and 11h.

Furthermore, since the through holes 11d and 11e communicating with the cylinder block cooling jacket JB and the cooling water passages 11g and 11h communicating with the cylinder head cooling jacket JH branch in the cooling water passage 11c formed in the cylinder The branch parts in the body 11, therefore, no special seals need to be provided in the branch parts, thereby reducing the number of parts.

When the temperature of the cooling water rises abnormally during the operation of the engine E, a warning that the engine E may be overheated may be issued. In this embodiment, the cooling water temperature sensor 67 for the cooling system is arranged on the upper end of the exhaust manifold cooling water jacket JM2, and the cooling system includes the first exhaust guide cooling water jacket JM1, the exhaust manifold cooling water The jacket JM2 and the cylinder block cooling water jacket JB, while the cooling water temperature sensor 89 for the cooling system including the cylinder head cooling water jacket JH is arranged near the second thermostat 85 .

In this way, all four water cooling jackets, namely, the first exhaust guide cooling water jacket JM1, the exhaust manifold cooling water jacket JM2, the cylinder block cooling water jacket JB and the cylinder head cooling water jacket JH are divided into two systems. Therefore, only one cooling water temperature sensor 67 needs to be provided for the first exhaust guide cooling water jacket JM1 , the exhaust manifold cooling water jacket JM2 and the cylinder block cooling water jacket JB. Therefore, the number of components can be reduced compared to the case where each of the four water cooling jackets is provided with a cooling water temperature sensor.

In particular, because in the first exhaust guide cooling water jacket JM1, the exhaust manifold cooling water jacket JM2, and the cylinder block cooling water jacket JB, the cooling water temperature sensor 67 is arranged in the exhaust gas upstream of the cylinder block cooling water jacket JB. Manifold cooling water jacket JM2, therefore, an abnormal increase in cooling water temperature can be quickly detected. Moreover, because the cooling water temperature sensor 67 of the exhaust manifold cooling water jacket JM2 is arranged near the pipe joint 61e connected to the water inspection outlet 66, the cooling water flow to the water inspection outlet 66 can prevent the cooling water from staying at the cooling water temperature sensor 67. Nearby, thus providing the accuracy of cooling water temperature detection.

The first thermostat 84 is used to control the discharge of cooling water from the cylinder block cooling water jacket, the second thermostat 85 is used to control the discharge of cooling water from the cylinder head cooling water jacket JH, the first thermostat 84 and the second thermostat Two thermostats 85 are arranged on the upper wall of the chain cover 31 covering the timing chain 30 which provides the connection between the crankshaft 13 and the cam 73 on the upper surface of the engine E . Therefore, the first and second thermostats 84 and 85 can be easily serviced from above by removing only the engine cover 40 without being obstructed by the chain cover 31 or the timing chain 30 .

In addition, since the cooling water passages 31b and 31c providing connection between the cylinder block cooling water jacket JB and the first thermostat 84 and the cooling water passages 31b and 31c providing connection between the cylinder head cooling water jacket JH and the second thermostat 85 The cooling water passages 31d and 31e are formed in the chain cover 31, and therefore, the number of parts can be reduced compared to the case of connecting by external pipes. Moreover, since the outlet sides of the first and second thermostats 84 and 85 are connected to the second exhaust guide member cooling water jacket JM3 through the common drain pipe 88, it is not only unnecessary to form cooling water inside the engine E The passage of the discharge can be easily machined, and only one drain pipe 88 is required, thereby reducing the number of parts.

Also, since the first thermostat 84 on the cylinder block 11 side and the second thermostat 85 on the cylinder head 15 side are arranged close to each other, and the first and second thermostats 84 and 85 are installed in On the chain cover 31, which connects the cylinder block 11 and the cylinder head 15 through a common gasket surface, it is possible to compactly install the first and second thermostats 84 and 85 in a limited space. In particular, since the thermostat chambers 94 and 95 housing the first and second thermostats 84 and 85 are arranged above the rotation plane of the timing chain 30, mutual interference can be avoided, thereby preventing an increase in size, and obtain a compact structure. Also, the cooling water passages 31b and 31d communicating with the thermostat chambers 94 and 95 are arranged within the loop of the timing chain 30, so the dead space can be effectively used to prevent size increase, so as to obtain compact structure. Also, since the cooling water is discharged from the highest portion of the cylinder block cooling water jacket JB and the highest portion of the cylinder head cooling water jacket JH, the cooling water is easily discharged.

Furthermore, since the upper side pipe joint 11a for supplying cooling water to the cylinder block cooling water jacket JB is arranged not at the side of the tallest combustion chamber 20 but at the side of the second tallest combustion chamber 20, It is therefore possible to prevent the first thermostat 84 from being improperly operated due to the low-temperature cooling water supplied from the pipe joint 11a acting on the first thermostat. Furthermore, for the proper functioning of the first thermostat 84 , the nipple 11 a will be arranged at least below the vertical middle position of the uppermost combustion chamber 20 .

One embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the subject matter of the present invention.

For example, in the present embodiment, a multi-cylinder engine E is shown, but the present invention can also be applied to a single-cylinder engine.

Claims (3)

1. water-cooled vertical engine comprises:

Bent axle, this bent axle is arranged vertically substantially;

Camshaft;

Engine body;

Lid;

Annular transmission part shell chamber, this annular transmission part shell chamber is by forming on the upper surface that lid is connected engine body;

The annular transmission part is used for the driving force of bent axle is passed to camshaft, and this annular transmission part is arranged in the annular transmission part shell chamber;

Wherein, this motor also comprises:

Be formed at the water jacket in the engine body; And

Thermostat is used for being controlled at the flow of the cooling water of water jacket, and this thermostat is arranged in the thermostat fitting seat, and the position of this thermostat fitting seat above described annular transmission part is formed on the lid;

Cooling water passage is used for providing connection between water jacket and thermostat, and this cooling water passage and this lid are integrally formed.

2. water-cooled vertical engine according to claim 1 is characterized in that: it also comprises waste pipe, is used for discharging cooling water from thermostat, and this waste pipe is and this lid separated components.

3. outboard motor that is equipped with water-cooled vertical engine comprises:

Bent axle, this bent axle is arranged vertically substantially;

Camshaft;

Engine body;

Lid;

Annular transmission part shell chamber, this annular transmission part shell chamber is by forming on the upper surface that lid is connected engine body;

The annular transmission part is used for the driving force of bent axle is passed to camshaft, and this annular transmission part is arranged in the annular transmission part shell chamber;

Wherein, this motor also comprises:

Be formed at the water jacket in the engine body;

Water pump is used for supplying with cooling water to described water jacket; And

Thermostat is used for being controlled at the flow of the cooling water of water jacket, and this thermostat arranges that the position of this thermostat fitting seat above described annular transmission part is formed on the lid in thermostat fitting seat;

Cooling water passage is used for providing connection between water jacket and thermostat, and this cooling water passage and this lid are integrally formed.

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