JPH09317427A - Engine exhaust structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously hold at an appropriate temperature the engine oil in an outboard motor V-engine provided on the outer periphery of its exhaust collector passage with an exhaust-cooling water passage, by providing an oil- cooling water passage in which cooling oil after cooling the exhaust collector passage flows in adjacent to the main oil passage in the engine. SOLUTION: When an outboard motor 1 is operated, the cooling water is taken in from a water intake 25 by a cooling water pump 26 coupled with a drive shaft 14, is led through an exhaust-cooling water passage 44 while cooling an exhaust collector passage 19 from the lower part to upper part thereof, and is then directed from the upper part to the upper part of an oil- cooling water passage and downward therethrough while cooling a main oil passage 55. The cooling water is also led into the cylinder head and cylinder block to cool the cylinder and therearound. The cooling water is thereafter divided into two A and B systems; the A system cools an oil pan 23 and therearound and is discharged into the water, while the B system flows through jackets around an exhaust pipe 22 to a maim exhaust chamber 21 where it is discharged into exhaust gas, and passes around a propeller shaft 16 together with the exhaust gas to be discharged into the water at the rear end thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust structure of an engine, and more particularly to an exhaust structure of a vertically arranged four-cycle V-type engine for an outboard motor.

[0002]

2. Description of the Related Art A two-cycle V-type engine has been put to practical use as an engine for an outboard motor, and a four-cycle V-type engine has been disclosed in Japanese Patent Application Laid-Open No. Hei 6-264775.

According to the prior art described in this publication, an exhaust port is provided inside each bank arranged in a V-shape in a four-stroke V-type engine for an outboard motor arranged vertically, and an exhaust port communicating with the exhaust port is provided. A compact V-type engine structure is achieved by connecting the passage to an exhaust pipe below the engine and arranging an intake port and an intake system communicating with the intake port outside each bank.

In such an outboard motor, as in a normal engine, lubricating oil for each drive section of the engine is circulated. In order to obtain a good lubricating effect with such oil, it is desirable to always circulate the oil at a substantially constant temperature regardless of the operating state of the engine and the surrounding environmental conditions.

Particularly, the outboard motor has a special use condition that it directly takes in and circulates seawater or the like as engine cooling water, and it is necessary to maintain a particularly reliable operation state for operation at sea. It is necessary to properly manage the oil temperature in order to ensure engine performance.

[0006]

However, in the conventional V-type engine having the above exhaust structure, the oil temperature is easily affected by the engine temperature and the ambient environment temperature, stable temperature control cannot be performed, and proper lubrication action is not achieved. Could not be obtained.

The present invention has been made in view of the above problems, and provides an exhaust structure for a V-type engine capable of effectively controlling the temperature of the engine oil and keeping the engine oil always at an appropriate temperature. The purpose is to

Furthermore, after achieving such oil temperature control, the cooling system is improved to effectively cool the engine and the exhaust system, and the exhaust passage area is expanded to secure stable engine performance. The purpose is to provide the designed V-type engine.

[0009]

In order to achieve the above object, in the present invention, an exhaust collecting passage where the exhaust passages of a plurality of cylinders gather is provided along a parallel cylinder block, and the exhaust collecting passage has an outer circumference. In an exhaust structure of an engine having an exhaust cooling water passage for cooling the same, an oil cooling water passage through which cooling water after cooling the exhaust collecting passage passes is provided adjacent to a main oil passage of the engine. Provide an engine exhaust structure.

According to the above structure, even if the engine becomes hot due to the thermal energy generated during combustion, the engine oil supplied to each part of the engine cools the exhaust collecting passage in the main oil passage before branching to each portion. It is efficiently and stably cooled by the subsequent cooling water, and is kept at an appropriate temperature evenly. Further, when the temperature of the engine oil is low such as at the time of start-up, the engine oil absorbs heat from the cooling water whose temperature has risen by cooling the exhaust gas collecting passage, quickly raises to an appropriate temperature, and is kept at an appropriate temperature. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
An exhaust passage of each cylinder is formed toward the inside of a bank arranged in a V-shape, and exhaust collecting passages where the exhaust passages gather are provided along a parallel cylinder block, and the exhaust collecting passages are provided on the outer periphery of the exhaust collecting passage. V with exhaust cooling water channel for cooling
It is characterized by being applied to a mold engine.

In a further preferred embodiment, a pressure valve for discharging the cooling water when the pressure exceeds a predetermined pressure is provided at a portion of the exhaust cooling water passage immediately after cooling the exhaust collecting passage.

In another preferred embodiment, the cooling system is provided with a thermostat that shuts off the water passage when the engine temperature falls below a predetermined temperature, and a control valve that adjusts the amount of water according to the water temperature. Characterize.

Further, in another preferred embodiment, the exhaust cooling water passage is provided separately from the cylinder cooling water jacket.

Further, in another preferred embodiment, the cylinder block is constituted by a plating cylinder having a sliding surface plated.

[0016]

FIG. 1 shows a 4-cycle 6 according to an embodiment of the present invention.
FIG. 2 is a main part configuration diagram of an outboard motor equipped with a vertical cylinder V-type engine. FIGS. 2 to 4 are detailed structural diagrams of the upper part, the central part, and the lower part of the outboard motor of FIG.

The outboard motor 1 is clamped to a shipboard 3 at the rear of the hull via a bracket 2 and is rotatably mounted around a tilt shaft 2a by a hydraulic cylinder (not shown) or manually. The outboard motor 1 is further rotatable about the swivel shaft 4 and is steerably mounted.

On the outside of the outboard motor 1, a cowling 5 consisting of an upper cowling 5a and a lower cowling 5b, which are engine storage parts, and an upper casing 6 below the cowling 5 are provided.
a and the lower casing 6b. Cowling 5
Inside, a 6-cylinder V-type engine 7 is housed in a vertical arrangement in which the axis 13 (FIG. 1) of the crankshaft 52 (FIG. 2) is arranged substantially vertically during operation. An intake passage 11, which will be described in detail later, is connected to the cylinder head 8 of each cylinder of the engine 7. FIG. 1 shows three intake passages 11 connected to one bank of three vertically arranged three cylinders in a six-cylinder V-type arrangement. Each intake passage 11 branches off from a surge tank 10, and an intake pipe 9 communicating with the outside air is connected to the surge tank 10. On the intake pipe 9, a throttle body 62 provided with a butterfly valve for adjusting the amount of intake air and the like is mounted.

On the upper part of the engine 7, there is a flywheel 12
Are mounted coaxially with the crankshaft 52 (FIG. 2) by fastening with a nut 51. A pulley 58 (FIG. 2) is mounted below the flywheel 12 and is connected to an alternator (not shown). The upper part of the flywheel 12 is covered with a flywheel cover 57 (FIG. 2). A chain 60 for driving a valve cam is mounted on the crankshaft 52 below the pulley 58, and opens and closes an intake valve and an exhaust valve (not shown) of each cylinder in synchronization with the crankshaft 52. The chain 60 is covered with a chain cover 59.

The head 53 of the drive shaft 14 is fixedly connected to the lower side of the crankshaft 52 below the engine. A transmission mechanism 15 (FIG. 1) composed of a bevel gear, a dog clutch, and the like is attached to the lower end of the drive shaft 14. Via this transmission mechanism 15, the rotation of the engine is selected in the forward or reverse direction, and the propeller is driven. It is transmitted to the shaft 16. A propeller 17 is mounted on the rear end of the propeller shaft 16.

An exhaust passage 18 is provided from each cylinder of the engine 7.
Are provided toward the inside of the left and right banks as described later. Each exhaust passage 18 extends vertically inside the left and right banks,
The cylinders 31 of the engine 7 communicate with each other in an exhaust collecting passage 19 formed downward along the cylinder block 31 (FIG. 5) of each cylinder.

The engine 7 is fixed to the upper surface of the upper casing 6a via an exhaust guide 20 (FIG. 3). An oil pan 23 is attached to the lower side of the exhaust guide 20. Exhaust guide 20
An exhaust passage 43 is formed substantially at the center. The exhaust collecting passage 19 of each of the left and right banks communicates with the exhaust passage 43 (FIGS. 1 and 2) of the exhaust guide 20. An exhaust pipe 22 is provided below the exhaust guide 20 so as to be continuous with the exhaust passage 43. The exhaust pipe 22 is disposed facing the main exhaust chamber 21 in the upper casing 6a. The exhaust gas from the engine 7 passes through each exhaust passage 18, the exhaust collecting passage 19, the exhaust passage 43, and the exhaust pipe 22, and
1, is guided further downward, passes through the annular space around the propeller shaft 16, and is discharged from the rear end into the water.

An oil pan 23 is provided inside the upper casing 6a below the exhaust guide 20, and an oil strainer 24 is provided inside the oil pan 23. The lower end of the crankshaft 52 (FIG. 2) (the head 53 of the drive shaft 14)
Is equipped with an oil pump 50. The oil in the oil pan 23 is sucked by the oil pump 50 via the oil strainer 24, and is pumped to the engine through the main oil passage 55 (FIGS. 1 and 2). From the main oil passage 55, a branch oil passage 56 communicating with each cylinder and the valve cam shaft is formed. The oil circulates around the camshaft and crankshaft inside the engine and around the cylinder block through these branch oil passages 56, and is returned to the oil pan 23.

The cooling water is taken in through the water intake 25 by the cooling water pump 26 (FIGS. 1 and 4) connected to the drive shaft 14. This cooling water is guided upward as indicated by the arrow in the figure, and first cools the exhaust collecting passage 19 from below through an exhaust cooling water passage 44 formed around the exhaust collecting passage 19, From above, the main oil passage 55
After being introduced into the upper part of the oil cooling water passage 85 adjacent to and cooled down to cool the main oil passage 55, it is further introduced into the cylinder head and the cylinder block to cool around the cylinder. Thereafter, as shown in the figure, the system is divided into two systems, A and B. The system A cools around the oil pan 23 and is discharged into the water. The system B is exhausted in the main exhaust chamber 21 through the jacket around the exhaust pipe 22. The exhaust gas merges with the exhaust gas, passes around the propeller shaft 16 together with the exhaust gas, and is discharged into the water from the rear end. By flowing the cooling water through such a path, not only the exhaust collecting passage 19 and around the cylinder but also the main oil passage 55 and the oil pan 23 can be cooled. Even if the temperature of the engine 7 becomes high, the engine oil is cooled by the cooling water after cooling the exhaust collecting passage 19 and is kept at an appropriate temperature. If the temperature of the engine oil is lower than the temperature of the cooling water after cooling the exhaust collecting passage 19, the engine oil absorbs heat from the cooling water after cooling the exhaust collecting passage 19 and maintains the temperature at an appropriate temperature. Dripping.

As described above, in this embodiment, the cooling water is made to flow in the oil cooling water passage 85 adjacent to the main oil passage 55 from the direction opposite to the oil flow, so that the oil before being branched to the various parts of the engine can be efficiently supplied. Can be cooled to. In this case, the cooling water which directly takes in seawater or the like cools the oil after the exhaust collecting passage 19 is cooled by the exhaust heat and is appropriately heated by the exhaust heat. The oil is warmed by the cooling water, and the rise of the oil temperature at the time of starting or the like is assisted, so that a stable engine operating state can be quickly reached.

The exhaust cooling water passage 44 and the oil cooling water passage 8
A pressure valve that discharges the cooling water when the pressure becomes equal to or higher than a predetermined pressure is provided in a portion of the water passage between the first and second water passages immediately after cooling the exhaust collecting passage 19. Further, at a suitable position of the water passage of such a cooling system (for example, near the crank chamber), a thermostat for shutting off the water passage including the cooling water passage 85 adjacent to the main oil passage 55 when the temperature of the engine 7 becomes a predetermined temperature or less. And a control valve that adjusts the amount of water according to the water temperature.

When the engine rotates, the cooling water pump directly connected to the crankshaft rotates to circulate the cooling water as described above. At this time, if the engine temperature is low, the cooling water passage is closed by the thermostat while the pump is rotating, and the pressure increases. This pressure increase is released by the pressure valve. By providing this pressure valve at the upper end of the exhaust cooling water passage 44, only the exhaust is constantly cooled even when the circulation of the cooling water in the engine is stopped by the thermostat, so that an appropriate engine operating state is maintained.

Further, by the action of the control valve,
When the thermostat is opened, it is possible to prevent rapid cooling of the engine by rapidly circulating a large amount of cooling water at a low temperature, thereby preventing unstable combustion due to a rapid temperature change. This control valve controls the flow rate according to the valve opening area of the thermostat and the water temperature.

The arrangement of such a pressure valve, thermostat and control valve is shown in FIG. As shown, the pressure valve 300 is provided at the upper end of the exhaust cooling passage 44. This pressure valve 3
The outlet of 00 is connected to the cooling pipe before branching to the above-mentioned A system and B system at the most downstream part of the cooling pipe around the cylinder via the pressure valve return passage. By providing the pressure valve 300 at the upper end of the exhaust cooling passage 44, as described above, the area around the exhaust is always reliably cooled,
Thermal distortion of the cylinder and the like can be prevented.

The thermostat 302 is provided on the cooling pipe after cooling around the cylinder. This makes it possible to cool the entire area around the cylinder at an appropriate temperature. Further, the control valve 301 is provided in the exhaust guide 20 on the cooling water passage before the cylinder is cooled or immediately before the cylinder is cooled as shown in the drawing. Thereby, the cooling control of the cylinder is reliably performed, a large amount of low-temperature cooling water is prevented from flowing at a time, and appropriate temperature management of the cylinder is achieved. In this case, if a control valve is installed on the cooling water passage just before the cylinder after cooling around the exhaust,
Only the cylinder is controlled to be cooled by the cooling water of the flow rate appropriately reduced, and the exhaust gas is always cooled by the entire cooling water amount before the flow rate is reduced by the control valve, thereby achieving a reliable exhaust cooling action.

FIG. 11 shows such a cooling water circulation path. As described above, the cooling water is sent from the water pump 26, passes through the control valve 301, flows around the exhaust gas,
Around the cylinder and the head are cooled at the same time, or around the exhaust is cooled first, and after the cylinder and the head are cooled, they are discharged through the thermostat 302.

FIG. 5 is a horizontal sectional view of the main part of the engine portion in the cowling of the above embodiment, where F is the front side and R is the rear side. FIG. 6 is a rear view of the engine.
The engine 7 is composed of two banks 30a and 30b, which are vertically arranged in three cylinders of V-shape on both left and right sides diagonally rearward from the crankshaft 52. The cylinder head 31 of each cylinder of each bank includes a cylinder block 31. Are joined together, and each cylinder block 31 is fixed to the crankcase 74. Crank case 74 that accommodates this crank shaft 52
Are assembled and fixed to the V-shaped cylinder block 31 by bolts 75 (only one is shown in the figure) provided at appropriate plural locations. A starter motor 72 for rotating the flywheel 12 at startup and a generator (alternator) 73 rotating with the crankshaft 52 on the opposite side are provided on both outer sides of the crankcase 74.
Is provided. Further, on the front side of the crankcase 74, a vapor separator 81 having a high-pressure pump and a regulator is provided. This vapor separator 8
1 is a state in which the fuel introduced from the fuel tank placed in the hull by the low-pressure pump 86 through the filter 87 is made high in pressure by the high-pressure pump, and is supplied to the engine of the engine through the horizontally extending supply passage 88. A fuel passage 89 extending upward along the right bank 30a is raised to supply it to the injector 38 provided in each cylinder head 8, and a fuel passage 83 extending downward along the left bank 30b via a communication passage 90. Is lowered and supplied to the injector 38 provided in each cylinder head 8, and then circulated through the return passage 82 extending in the horizontal direction.

Each cylinder block 31 is formed toward the rear of the common crank chamber 32, and the inside of the piston 34
Slides. Each piston 34 and the crankshaft 52 are connected via the connecting rod 33 at a predetermined crank phase difference angle.

An intake surge tank 10 and an intake passage 11 are provided in each of the left and right banks 30a and 30b, and communicate with the intake passage 35 of each cylinder. In the middle of the intake passage 35 of each cylinder, the injector 38
, And an intake valve 36 is attached to an intake port at the end of the intake passage. The intake valve 36 includes a cam (not shown) in which a valve lifter 77 at the upper end of the valve shaft is mounted on a cam shaft 37 that rotates in synchronization with the crank shaft 52.
8, it slides along the valve guide 76, and opens and closes in synchronization with the rotation of the crankshaft 52.

Cylinder block 31 made of aluminum alloy
A cylinder sleeve 70 made of cast iron or the like is press-fitted into the inner surface of the cylinder for smooth sliding operation of the piston 34.

An exhaust passage 18 is formed in the cylinder head 8 of each cylinder, and an exhaust valve 39 is provided at the end of the exhaust passage 18.
Is attached. Each exhaust valve 39 is opened and closed at a predetermined timing by a cam mounted on a camshaft 40 similarly to the intake valve 36. A hole for mounting a spark plug is formed in the center of each cylinder head 8. As shown in the figure, the three exhaust passages 18 of each bank are formed inside the left and right banks 30a, 30b in the cylinder head 8 obliquely forward. An exhaust cooling water passage 44 is formed around the exhaust collecting passage 19 in which the six exhaust passages 18 of both banks are gathered. As described above, the cooling water sent from the cooling water pump 26 passes first, This exhaust passage 19 is first cooled.

The exhaust collecting passage 19 is, as shown in FIG.
At the lower end, exhaust of all six cylinders of both banks is gathered. For example, # 1 of the right bank, # 1 of the left bank
2, # 3 in the right bank, # 4 in the left bank, # in the right bank
5. The exhaust of the cylinder # 6 in the left bank merges sequentially from the top, and all the exhaust gather at the lower end. The collected exhaust gas communicates with the exhaust passage 43 of the exhaust guide 20.

In the vertically arranged V-type engine having the above-mentioned structure, as described above, the temperature of the engine oil can be appropriately controlled to maintain stable operation and improve the engine performance. Since it is formed inside the bank, the angle between the banks can be reduced to reduce the engine width and the length in the front-rear direction.
The outboard motor engine can be made compact.

Further, in such a configuration, the circulation path of the cooling water is initially the exhaust collecting passage 19 inside both banks.
Is cooled, then the main oil passage 55 is cooled, and then the cooling around the cylinder is performed. Therefore, the exhaust collecting passage 19 provided inside both banks is efficiently cooled, The cylinder block 31 is not excessively affected by the heat of the collecting passage 19 and is not deformed or overheated.

Further, in this case, the cooling water which cools the exhaust collecting passage 19 and further cools the main oil passage 55 and has a substantially uniform proper temperature is sent around the cylinder, so that the engine temperature management and control are proper. The stable combustion is obtained, which is advantageous in combustion. Especially in the case of outboard motors, the surroundings of the cylinders are cooled directly by seawater, etc., so the water temperature may be too low or the temperature fluctuations may be too large, making it very difficult to control the temperature of the cooling water. Cooling around the cylinder after the temperature has risen to a substantially stable constant temperature provides a stable combustion action.

7 and 8 are a side view and a front view showing the intake system portion of the above embodiment, respectively. As shown in the figure, two intake surge tanks 10 and 10 are provided corresponding to each of the left and right banks, and an intake passage 9 is connected to upper portions of both surge tanks 10. A throttle body 62 for adjusting the amount of intake air is provided above the center of the intake passage 9. Three intake passages 11 are branched from each surge tank 10 and are vertically arranged in each bank.
It is connected to each intake passage 35 (FIG. 5) of one cylinder. The three intake passages 11 connecting the surge tank 10 and each cylinder have their central intake passages bulged outward in order to equalize the intake passage length and make the combustion state in each cylinder uniform. That is, the intake passage 1 shown by the hatched cross section in FIG.
Reference numeral 1 denotes two upper and lower intake passages, and an intake passage 11 expanded to the outside and shown in a white cross section without hatching shows a central intake passage. With such a configuration, the lengths of the intake passages 11 for the respective cylinders become equal, and a uniform combustion action can be obtained.

FIG. 9 is a horizontal sectional view of an essential part of an engine portion in a cowling according to another embodiment of the present invention, where F is the front side and R is the front side.
Indicates the rear side. In the example of FIG. 5, the exhaust cooling water passage 44, which is the cooling water passage around the exhaust collecting passage 19, and the cooling water passage 45 around the cylinder are formed separately, but in this embodiment,
Both were formed integrally. According to this, not only can the engine oil be heated to an appropriate temperature as in the above-described embodiment, but the cross-sectional area of the exhaust collecting passage 19 can be increased by the amount that the cooling water passage is integrated from a separate body. Therefore, the exhaust efficiency can be improved.

FIG. 10 is a horizontal sectional view of an essential part of an engine portion in a cowling according to still another embodiment of the present invention, where F is the front side and R is the rear side. In the example of FIG. 5, the cylinder block 31 has a structure in which the cylinder sleeve 70 is press-fitted to the inner surface of the cylinder block 31 in order to make the sliding motion of the piston 34 smooth. It is composed of a plating cylinder for plating the inner surface. According to this, the engine oil can be made to have an appropriate temperature by the cooling water passage, as in the two embodiments described above.
By making the cylinder wall thinner by making the cylinder sleeve plated, the cross-sectional area of the exhaust collecting passage 19 can be made larger and the exhaust efficiency can be improved.

[0044]

As described above, in the present invention, since the cooling water passage after cooling the exhaust collecting passage is provided adjacent to the engine oil passage, the engine is heated to a high temperature due to the thermal energy generated during combustion. Even if it becomes, the engine oil can be efficiently cooled by the cooling water of an appropriate temperature after cooling the exhaust collecting passage, and conversely, when the engine is at a low temperature, the oil temperature is raised by the cooling water that is appropriately warmed by the exhaust gas. Therefore, the engine oil can always be kept at an appropriate temperature, a stable operating state can be maintained, and engine performance can be improved. Further, if the structure around the cylinder is also cooled when the exhaust collecting passage is cooled, the area of the exhaust collecting passage can be increased and the exhaust efficiency can be improved. Further, if the cylinder block is composed of a plated cylinder, the cylinder wall can be made thinner than the cylinder block in which the sleeve is press-fitted into the inner surface, and the exhaust collecting passage area can be correspondingly increased to improve the exhaust efficiency. be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of an outboard motor to which the present invention is applied.

2 is a detailed view of an upper portion of the outboard motor of FIG. 1. FIG.

FIG. 3 is a detailed view of a central portion of the outboard motor of FIG. 1;

FIG. 4 is a detailed view of a lower portion of the outboard motor of FIG. 1;

FIG. 5 is a horizontal sectional view of a main part of the outboard motor of FIG. 1;

FIG. 6 is a rear view of an engine portion of the outboard motor of FIG. 1;

FIG. 7 is a side view of an intake system of the outboard motor of FIG. 1;

FIG. 8 is a front view of an intake system of the outboard motor of FIG. 1;

FIG. 9 is a horizontal sectional view of a main part of another embodiment of an outboard motor to which the present invention is applied.

FIG. 10 is a horizontal cross-sectional view of a main part of still another embodiment of the outboard motor to which the present invention is applied.

FIG. 11 is a route diagram showing a cooling water circulation flow of the present invention.

[Explanation of symbols]

1: outboard motor, 2: bracket, 2a: tilt shaft, 3: boat plate, 4: swivel shaft, 5: cowling, 5a: upper cowling, 5b: lower cowling, 6a: upper casing, 6b: lower casing, 7 : Engine, 8: cylinder head, 9: intake pipe, 10: surge tank, 11:
Intake passage, 12: flywheel, 13: shaft, 14: drive shaft, 15: transmission mechanism, 16: propeller shaft, 17: propeller, 18: exhaust passage, 19: exhaust collecting passage, 20: exhaust guide, 21: Main exhaust chamber, 22: exhaust pipe, 2
3: oil pan, 24: oil strainer, 26: cooling water pump, 30a, 30b: bank, 31: cylinder block, 32: crank chamber, 33: connecting rod, 34:
Piston, 35: intake passage, 36: intake valve, 37: camshaft, 38: injector, 40: camshaft, 43: exhaust passage, 44: exhaust cooling water passage, 50: oil pump, 51:
Nut, 52: crankshaft, 53: head, 55: main oil passage, 56: branch oil passage, 57: flywheel cover, 58: pulley, 59: chain cover, 6
0: chain, 62: throttle body, 70: cylinder sleeve, 72: starter motor, 73: generator,
74: crankcase, 75: bolt, 76: valve guide, 77: valve lifter, 78: spring, 81:
Vapor separator, 82: Return passage, 85: Oil cooling water passage, 86: Low pressure pump, 87: Filter, 88: Supply passage, 89: Fuel passage, 90: Communication passage, 300: Pressure valve, 301: Control valve, 302: thermostat

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02B 67/00 F02B 67/00 ML

Claims (6)

[Claims] 1. An exhaust structure for an engine, wherein an exhaust collecting passage for collecting exhaust passages of a plurality of cylinders is provided along a parallel cylinder block, and an exhaust cooling water passage for cooling the exhaust collecting passage is provided on an outer periphery of the exhaust collecting passage. An engine exhaust structure, wherein an oil cooling water passage through which cooling water after cooling the exhaust collecting passage passes is provided adjacent to a main oil passage of the engine. 2. An exhaust passage of each cylinder is formed toward the inside of a bank arranged in a V shape, and an exhaust collecting passage where the exhaust passages are gathered is provided along a parallel cylinder block, and the exhaust collecting passage is provided. The exhaust structure for an engine according to claim 1, wherein the exhaust structure is applied to a V-type engine provided with an exhaust cooling water channel for cooling the same on the outer periphery thereof. 3. The engine according to claim 1, wherein a pressure valve that discharges the cooling water when the pressure exceeds a predetermined pressure is provided in a portion of the exhaust cooling water passage immediately after cooling the exhaust collecting passage. Exhaust structure. 4. The cooling system is provided with a thermostat that shuts off the water passage when the engine temperature falls below a predetermined temperature, and a control valve that adjusts the amount of water according to the water temperature. Exhaust structure of the engine described. 5. The exhaust structure for an engine according to claim 1, wherein the exhaust cooling water passage is provided separately from a cylinder cooling water jacket. 6. The exhaust structure for an engine according to claim 1, wherein the cylinder block is composed of a plated cylinder whose sliding surface is plated.