JPH09324653A - Intake structure of four cycle v type engine for outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attempt to effectively use space and house effectively engine auxiliary device to provide a compact structure and to attain uniform and stable combustion. SOLUTION: Inside right and left banks of a vertically installed V-type engine, an exhaust system is provided, an intake pipe is provided outside banks. And a surge tank 10 which is communicated to each of the right and the left intake pipes is provided separately right and left in front of the engine 10. Then, on a central part of an intake passage 9 to which the right and the left surge tanks are connected, an upward throttle body 62 is provided, and a engine auxiliary devices 81, 86 and 87 are provided between right and left surge tanks on the lower side of this throttle body.

Description

Detailed Description of the Invention

[0001]

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

[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.

[0004] In such an outboard motor, engine accessories such as a starter motor, an alternator or a fuel system filter, a pump, and a vapor separator, which are essential components for driving the engine, are provided inside a cowling for housing the engine. It needs to be stored extremely compactly in a limited space. In addition, it is important to improve the reliability of operation, especially from the special situation of operation at sea, and it is necessary to perform uniform combustion control for each cylinder and always achieve stable operation.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to further improve the V-type engine described in the above publication, to effectively utilize the space, and to effectively house the engine auxiliary equipment to make it more compact. The object is to realize an intake pipe structure of a V-type engine that obtains a structure and achieves uniform and stable combustion.

[0006]

In order to achieve the above object, in the present invention, exhaust pipes are provided inside the left and right banks of a vertically installed V-type engine, intake pipes are provided outside the banks, and each of the left and right intake pipes is provided. Surge tanks that communicate with each other are provided on the left and right sides of the front of the engine, and an upward throttle body is provided at the center of the intake passage that connects the left and right surge tanks. Provided is an intake structure for a four-cycle V-type engine for an outboard motor, which is provided.

In such a configuration, engine accessories can be arranged between the intake surge tanks provided on the left and right sides of the front side of the engine, so that the space can be effectively used and a compact structure can be obtained. In this case, since the auxiliary machine is arranged on the front side of the engine, the weight balance becomes appropriate when the outboard machine is mounted on the stern, and the shape is also arranged in a well-balanced manner. Also, since the left and right banks are separate units, they can be controlled independently, and combustion control such as exhaust gas recirculation (EGR) to the intake side, fuel injection timing, air-fuel ratio control, etc. can be performed for each cylinder. In addition to the above, the intake system can be controlled more finely by performing each bank.

Further, since the throttle body is provided in the center of the intake passage between the left and right surge tanks, the intake pipe lengths from the intake inlet to both banks are equal, and the air-fuel ratio of each cylinder in the bank is controlled uniformly. You can

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
A fuel supply system filter, a pump, and a vapor separator are provided between the left and right surge tanks below the throttle body.

Another preferred embodiment is characterized in that the surge tank side of the intake pipe that connects the cylinders of the left and right banks to the surge tank is connected to the surge tank by gathering in the central portion in the vertical direction. There is.

In still another preferred embodiment, the left and right banks are each composed of a plurality of cylinders, and the intake pipes in the central portion of the intake pipes are arranged so that the intake pipes from each cylinder to the surge tank have the same length. The feature is that the pipe is inflated to the outside of the upper and lower intake pipes to form an intake passage path.

[0012]

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 hull 3 at the rear of the hull via a bracket 2, and is mounted rotatably about 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.

The outer side of the outboard motor 1 is provided with a cowling 5 comprising an upper cowling 5a and a lower cowling 5b, which are engine storage portions, and an upper casing 6 below the cowling.
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.

A flywheel 12 is provided above the engine 7.
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 at the lower part of 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.

From each cylinder of the engine 7, an exhaust passage 18 is provided.
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.

Cooling water is taken in from a water inlet 25 by a 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.

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 an appropriate position of such a cooling system water passage, a thermostat that shuts off a water passage including a cooling water passage 85 adjacent to the main oil passage 55 when the temperature of the engine 7 falls below a predetermined temperature; And a control valve for adjusting the amount of water accordingly.

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. 5 is a horizontal cross-sectional view of a main part of the engine portion in the cowling of the embodiment, where F indicates the front side and R indicates 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 fuel introduced from a fuel tank placed in the hull by a low-pressure pump 86 through a filter 87 is made high-pressure by a high-pressure pump, and is supplied through a horizontally extending supply passage 88 to the engine. An upwardly extending fuel passage 89 extending along the right bank 30a is supplied to the injectors 38 provided in the cylinder heads 8, and furthermore, a downwardly extending fuel passage 83 extending along the left bank 30b via the communication passage 90. Is supplied to the injectors 38 provided in the cylinder heads 8 and then returned to the high-pressure pump via the pressure regulator 91 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 in the exhaust port at the end thereof.
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.

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 of the cylinders are provided with a central intake passage in order to make the intake passage length equal to make the air-fuel ratio in each cylinder equal and to control the combustion state uniformly. Is bulging outward. That is, the intake passage 11 shown by the hatched section in FIG. 5 shows two upper and lower intake paths, and the outwardly extending intake passage 11 shown by the open section without hatching shows the central intake passage. With such a configuration, the lengths of the intake passages 11 for the respective cylinders become equal, and the air-fuel ratios in the respective cylinders are made equal to obtain a uniform combustion action.

As shown in the figure, the three intake passages 11 of the three cylinders of each bank are connected to the surge tank 10 by gathering in the central portion in the vertical direction. With such a configuration, spaces are formed above and below the intake passage, and various engine accessories can be arranged in these spaces. In the above embodiment,
A starter motor 72 and an alternator 73 are laid out in the upper space. In this upper space,
Further, a vapor separator or the like can be laid out. It is also possible to lay out filters and pumps in the lower space.

Further, by thus gathering the intake passages 11 of the three cylinders in the center and connecting them to the surge tank 10, the surge tank outlet positions (connection positions) for the respective cylinders.
Is almost the same position for each cylinder, and the throttle body 62
And the distance between the cylinders becomes equal, the difference in air-fuel ratio between cylinders disappears, and uniform and stable operation control is achieved.

In the present embodiment, the above-mentioned separate surge tanks 10 on the left and right sides have the same shape, and the parts can be commonly used, which is advantageous in terms of manufacturing and cost.

The engine accessories provided above and below the intake passage of the central assembly layout of the above configuration, the engine accessories provided between the left and right surge tanks, and the like can be laid out as pre-modularized integrated unit parts. Such modularization improves assemblability, facilitates maintenance and maintenance, and facilitates parts management.

[0038]

As described above, according to the present invention, the exhaust pipes are provided inside the left and right banks of the vertical V-type engine, the intake pipes are provided outside the banks, and the surge tanks communicating with the left and right intake pipes are provided. Installed separately on the left and right of the front of the engine,
An upward throttle body is provided in the center of the intake passage that connects the left and right surge tanks, and an engine accessory is installed between the left and right surge tanks on the lower side of this throttle body. An engine auxiliary device can be arranged between the tanks, the space can be effectively used, and a compact structure can be obtained. In this case, since the auxiliary machine is arranged on the front side of the engine, the weight balance becomes appropriate when the outboard machine is mounted on the stern, and the shape is also arranged in a well-balanced manner. Also, since the left and right banks are separate units, they can be controlled independently, and combustion control such as exhaust gas recirculation (EGR) to the intake side, fuel injection timing, air-fuel ratio control, etc. can be performed for each cylinder. In addition to the above, the intake system can be controlled more finely by performing each bank.

Further, since the throttle body is provided in the center of the intake passage between the left and right surge tanks, the intake pipe lengths from the intake inlet to both banks are equal, and the air-fuel ratio of each cylinder in the bank is controlled uniformly. You can

Further, by collecting the three intake passages of the three cylinders of each bank, which communicate with the surge tank, at the central portion in the vertical direction and connecting them to the surge tank, a space is provided above and below this central collective intake passage. Once formed, various engine accessories can be placed in this space, and the space can be effectively used.

[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;

[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,

Claims (4)

[Claims] 1. An exhaust pipe is provided inside the left and right banks of a vertical V-type engine, intake pipes are provided outside the bank, and surge tanks communicating with the left and right intake pipes are provided separately on the left and right sides of the front of the engine. A four-cycle V for outboard motors characterized in that an upward throttle body is provided in the center of the intake passage communicating with the surge tank of the above, and an engine auxiliary device is provided between the left and right surge tanks below the throttle body.
-Type engine intake structure. 2. A four-cycle V-type engine for an outboard motor according to claim 1, further comprising a fuel supply system filter, a pump and a vapor separator provided between the left and right surge tanks below the throttle body. Intake structure. 3. The surge tank according to claim 1, wherein the surge tank side of the intake pipe for connecting the cylinders of the left and right banks to the surge tank is connected to the surge tank in a central portion in the vertical direction. An intake structure of the described 4-cycle V-type engine for an outboard motor. 4. The left and right banks are each composed of a plurality of cylinders, and the central intake pipe of the plurality of intake pipes is located outside the upper and lower intake pipes so that the length of the intake pipe from each cylinder to the surge tank is equal. The intake structure of a four-stroke V-type engine for an outboard motor according to claim 3, wherein the intake passage is formed by inflating the intake passage.