JPH09303155A - Exhaust structure for v-engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the compactness of a V-engine by providing an exhaust passage of each cylinder toward the inside of a bank arranged in a V type, and forming an exhaust collecting passage integrally with a cylinder head in each bank in the inside thereof. SOLUTION: An exhaust passage 18 from each cylinder, provided toward the inside of a right/left bank of a 4-cycle 6-cylinder vertical V type engine of outboard engine, is made to mutually communicate in an exhaust collecting passage 19 formed in a vertical direction in the inside of the right/left bank. These exhaust passage 18 and exhaust collecting passage 19 are integrally molded with a cylinder head 8 in the inside of the right/left bank, the exhaust collective passage 19 of each right/left bank is provided once toward a cylinder block side in a lower end part of the engine, made to join as the single exhaust passage 18 after bending in a crankshaft direction, made to communicate with the exhaust passage 18 of exhaust guide, to be connected to an exhaust pipe provided in a lower side of the exhaust guide. In this way, with a compact structure, the improvement of engine performance is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe structure for a V-type engine, and more particularly to a V-type engine installed vertically in an outboard motor.
It concerns the type engine.

[0002]

2. Description of the Related Art A two-cycle V-type engine has been put into practical use as an outboard engine, and a four-cycle V-type engine for an outboard motor is disclosed in Japanese Patent Laid-Open No. 6-264757.

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.

Such a V-type engine is mounted in an outboard motor casing composed of a cowling for housing an engine body and an upper casing and a lower casing for housing a lubrication system, a transmission mechanism and the like, and as a stern as an outboard motor. Mounted on. The casing of such an outboard motor expands at the center in the front-rear direction and narrows at the front-rear end to ensure performance such as propulsion efficiency under special conditions such as handling as an outboard motor and use at sea. In particular, the rear end is thin.

In a vertically arranged V-type engine, a vertically arranged crankshaft is arranged on the front side, and cylinder blocks and cylinder heads of each bank are arranged in a V-shape obliquely rearward and housed in a casing (coiling). To be done.

[0006]

However, in the V-type engine for an outboard motor described in the above publication, if the exhaust passage taken out from the cylinder head to the inside of each bank is lowered as it is, an exhaust pipe is provided. Although the exhaust passage is located on the rear side in the casing, in an outboard motor, the casing becomes narrower toward the rear end in terms of propulsion efficiency.Therefore, if the exhaust pipe is installed in the narrow space, sufficient exhaust passage disconnection will occur. The area cannot be taken and the engine performance cannot be improved.

In the technique proposed in the above publication, although the compactness of the engine has been improved, consideration of such a point is unclear, and it is considered that the engine performance cannot be sufficiently exhibited.

An object of the present invention is to provide an exhaust structure for a V-type engine by further improving and developing the conventional technique described in the above publication to enhance the compactness of the V-type engine and improve the engine performance.

[0009]

In order to achieve the above object, in the present invention, an exhaust passage of each cylinder is provided toward the inside of a bank arranged in a V shape, and an exhaust passage from each cylinder is provided for each bank. The exhaust structure of the V-type engine is characterized in that an exhaust collecting passage for collecting the exhaust gas is formed integrally with the cylinder head inside the bank, and the exhaust collecting passages of the banks are directed to the cylinder block side and then merged together. I will provide a.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
The engine is a V-type engine for outboard motors arranged vertically, and a portion where exhaust gas from all cylinders in the bank in the exhaust collecting passage in each bank is formed is formed at a lower end portion of each bank. It is characterized by that.

In another preferred embodiment, the engine is a vertically arranged V-type engine for an outboard motor, and exhaust from all cylinders in a bank is collected in the exhaust collecting passage in each bank. The part is characterized in that it is formed in the middle part of each bank.

[0012] In still another preferred embodiment, a V-type engine having an exhaust guide attached to a lower end portion of the engine, the exhaust collecting passages of the banks are joined on the engine side to form the exhaust guide. The feature is that they are connected.

In still another preferred embodiment, a V-type engine having an exhaust guide attached to a lower end portion of the engine, wherein exhaust collecting passages of each bank are directly connected to the exhaust guide. It is characterized by

A further preferred embodiment is characterized in that an elastic or flexible hose is interposed at the connecting portion between the exhaust collecting passage of each of the banks and the exhaust guide.

[0015]

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 ship plate 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.

The outside of the outboard motor 1 is provided with a cowling 5 including an upper cowling 5a and a lower cowling 5b which are engine storage parts, and an upper casing 6 below the cowling 5.
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. In the cylinder head 8 of each cylinder of the engine 7, as described later,
The intake pipe 11 is connected. In FIG. 1, three intake pipes 11 connected to one bank composed of vertically arranged three cylinders in a 6-cylinder V-type arrangement are shown. Each intake pipe 11 is branched from the surge tank 10, and an intake passage 9 communicating with the outside air is connected to the surge tank 10. On the intake passage 9, a throttle body 62 equipped with an intake air amount adjusting butterfly valve and the like is mounted.

At the top of the engine 7, there is a flywheel 12
Is mounted by being fastened and fixed by a nut 51 coaxially with the crankshaft 52. A pulley 58 is attached to the lower portion of the flywheel 12 and is connected to a starter motor (not shown). The top of the flywheel 12 is the flywheel cover 5
7 covered. A chain 60 for driving a valve cam is mounted on the crankshaft 52 below the pulley 58, and an intake valve and an exhaust valve (not shown) of each cylinder are opened and closed in synchronization with the crankshaft. An idler 61, which idles along the chain, is provided in the middle of the chain 60 to smoothly transfer the chain. 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 including a bevel gear, a dog clutch and the like is attached to the lower end portion of the drive shaft 14, and the rotation of the engine is selected in the forward direction or the reverse direction via the transmission mechanism 15 and transmitted to the propeller shaft 16. To be done. 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 toward the inside of the left and right banks, as will be described later. The exhaust passages 18 communicate with each other in an exhaust collecting passage 19 formed in the vertical direction inside the left and right banks. The exhaust passage 18 and the exhaust collecting passage 19 are integrally formed with the cylinder head 8 inside the left and right banks by casting, for example, an aluminum alloy.

The engine 7 is fixed to the upper surface of the upper casing 6a via an exhaust guide 20. Also,
An oil pan 23 is provided on the lower surface of the exhaust guide 20.
Is attached. An exhaust passage 43 is formed substantially at the center of the exhaust guide 20. The above-mentioned exhaust collecting passages 19 of the left and right banks are once directed to the cylinder block side at the lower end of the engine and bent in the crankshaft direction, and then these two exhaust collecting passages 19 merge into one exhaust passage. And communicates with the exhaust passage 43 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. This exhaust pipe 22
It is arranged so as to face the main exhaust chamber 21 in the upper casing 6a. Exhaust gas from the engine is introduced into the main exhaust chamber 21, guided further downward, passes through an annular space around the propeller shaft 16, and is discharged into the water from the rear end portion.

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. An oil pump 50 is attached to the lower end of the crankshaft 52 (the head 53 of the drive shaft 14). The oil in the oil pan 23 is sucked by the oil pump 50 via the oil strainer 24 and is pressure-fed to the engine side through the main oil passage 55. 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 cam shaft and crank shaft inside the engine and around the cylinder block through these branched 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 connected to the drive shaft 14. This cooling water is guided upward as shown by the arrow in the figure, and first, the cooling jacket 4 formed around the exhaust collecting passage 19 is formed.
4, the exhaust collecting passage 19 is cooled from the lower side, and is introduced into the cylinder head from the upper side to cool the periphery of the cylinder. After that, as shown in the figure, it is divided into A and B2 systems, the A system cools the periphery of the oil pan 23 and is discharged into the water, and the B system is discharged into the exhaust gas in the main exhaust chamber through the jacket around the exhaust pipe 22. The exhaust gas is combined with the exhaust gas, passes through the periphery of the propeller shaft 16 and is discharged into the water from the rear end portion together with the exhaust gas.

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 this engine part. The engine 7 includes two banks 3 vertically arranged in three cylinders of V-shape on the left and right sides diagonally behind the crankshaft 52.
Cylinder block 31 is joined to the cylinder head 8 of each cylinder of each bank, and each cylinder block 31 is fixed to a crankcase 74. The crankcase 74 accommodating the crankshaft 52 is assembled and fixed to the V-shaped cylinder block 31 by bolts 75 (only one is shown in the figure) provided at appropriate plural positions. A starter motor 72 for rotating the flywheel 12 at the time of starting and a generator (alternator) 73 rotating with the crankshaft on the opposite side are provided on both outer sides of the crankcase 74.

Each cylinder block 31 is formed toward the rear of the common crank chamber 32, and the piston 34 slides inside. 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. A fuel injection valve 38 is mounted in the middle of the intake passage 35 of each cylinder so as to face the intake passage, and an intake valve 36 is mounted on the valve seat 71 of the intake port at the end of the intake passage. The intake valve 36 causes the valve lifter 77 at the upper end of its valve shaft to be pressed against the valve guide 76 by a cam (not shown) mounted on the cam shaft 37 rotating in synchronization with the crankshaft 52 against the spring 78. It slides along and opens and closes in synchronization with crank rotation.

Syringa 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.

The exhaust passage 1 is provided in the cylinder head 8 of each cylinder.
8 is formed, and the valve seat 7 of the exhaust port at the end thereof is formed.
An exhaust valve 39 is attached to 1. Similar to the intake valve 36, each exhaust valve 39 is opened / closed at a predetermined timing by a cam attached to the cam shaft 40. A hole 41 for mounting a spark plug is formed in the center of each cylinder head 8. The three exhaust passages 18 of each bank are formed in the cylinder head 8 toward the inside of the left and right banks 30a and 30b, as shown in the figure. Further, an exhaust collecting passage 19 in which three exhaust passages 18 communicate with each bank is formed integrally with the cylinder head 8 inside the V-shaped bank. This exhaust collecting passage 1
A cooling jacket 44 is formed around 9 and, as described above, the cooling water sent from the cooling water pump first passes therethrough to cool the exhaust collecting passage 19 first.

As shown in FIG. 6, both the left and right exhaust collecting passages 19 have a structure in which exhaust from all three cylinders of each bank is collected at the lower end of the exhaust collecting passage 19 for each bank, for example, the right bank 30a. Then, the exhausts of the # 1, # 3, and # 5 cylinders are merged sequentially from the top, and all the exhausts are collected at the lower end. In the left bank 30b, the exhausts of the # 2, # 4, and # 6 cylinders are sequentially merged from the top. Then, all the exhaust gas gathers at the lower end. These collecting portions are bent toward the center side (cylinder block side) in the cylinder head below the engine to form a horizontal passage portion 40, which joins and communicates with the exhaust passage 43 of the exhaust guide 20.

In the vertically arranged V-type engine having the above structure, the exhaust gas collecting passage 19 taken out from the cylinder heads 8 of the left and right banks is temporarily directed to the cylinder block side, and then the left and right exhaust gases are discharged. Since the collecting passages are joined to each other and connected to the exhaust passage 43 of the exhaust guide 20 as one exhaust pipe, the combined exhaust pipe is provided in a wide space in the central portion of the outboard motor casing with a sufficient space. Therefore, the exhaust pipe cross-sectional area can be increased. As a result, it is possible to improve the engine performance with a compact structure.

Further, since the exhaust passage is formed inside the V-shaped bank, the bank included angle can be reduced to reduce the engine width and the length in the front-rear direction, thus making the outboard engine compact. It becomes possible to configure. In this case, since the exhaust pipe (exhaust collecting passage) provided between both banks is integrally molded with the cylinder head, the number of parts is reduced, the complexity of parts management is reduced, the manufacturing process is simplified, and the assembly error is caused. This eliminates the risk of causing a reliable product.

Further, in such a structure, the circulation path of the cooling water is configured such that the periphery of the exhaust gas collecting passage between both banks is first cooled and then the periphery of the cylinder is cooled. The provided exhaust passage is efficiently cooled, and the heat of the exhaust passage does not cause the cylinder block to be excessively thermally affected so as to be deformed or overheated.

Further, in this case, since the cooling water which has once cooled the exhaust collecting passage and has a substantially uniform proper water temperature is sent around the cylinder, the temperature management and control of the engine are properly performed, and stable combustion is obtained. It becomes advantageous in combustion. Especially in the outboard motor, since the circumference of the cylinder is directly cooled by seawater etc., the water temperature may be too low or the temperature fluctuation may be too large, so it is very difficult to control the temperature of the cooling water.
According to the configuration of the present invention, since the cooling water rises to a substantially stable constant temperature due to exhaust heat and then the periphery of the cylinder is cooled, a stable combustion action can be obtained.

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 intake air amount 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 the upper and lower intake passages, and the intake passage 11 expanded to the outside and shown in a white cross 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 a uniform combustion action can be obtained.

FIG. 9 is a configuration diagram of an exhaust collecting passage according to another embodiment of the present invention. In this embodiment, the exhaust gas of all the cylinders (three cylinders) in the bank of the exhaust collecting passage 19 in each bank is gathered at an intermediate portion in the vertical direction of each bank and is directed from the gathering portion of these exhaust collecting passages 19 toward the center side. Horizontal passages 40 are formed, and the horizontal passages 40 from both banks join to form a vertical exhaust passage 40 ', which is the exhaust guide 2
0 to the exhaust passage 43. Other configurations and operational effects are similar to those of the above-mentioned embodiment.

10 and 11 show another embodiment of the present invention. FIG. 10 is a side view of the exhaust collecting passage according to this embodiment, and FIG. 11 is a rear view of the engine. It is a figure. In this embodiment, the exhaust collecting passage 19 formed integrally with the cylinder head formed inside the V bank is not bent toward the center at the lower end thereof as in the structure of the first embodiment shown in FIGS. Directly communicates with the exhaust guide 20 as it is, and bends toward the center side (cylinder block side) below the exhaust guide 20,
These merge to form the exhaust pipe 22, and the exhaust pipe 22
Passing through the central part of the casing and passing through the main exhaust chamber 21 (Fig. 1)
It is configured to communicate with. Therefore, in this example, two exhaust passages 43 of the exhaust guide 20 are provided corresponding to the exhaust collecting passages 19 from each bank. in this way,
By directly connecting the exhaust collecting passage 19 to the exhaust guide 20 without bending the inside of the cylinder head, the structure of the cylinder head is simplified, which is advantageous for mold production and other casting. Other configurations and operational effects are similar to those of the above-mentioned embodiment.

12A and 12B show still another embodiment of the present invention, in which FIG. 12A is a longitudinal sectional view of an essential part thereof, and FIG. 12B is a rear view of the engine. This embodiment relates to the improvement of the joint between the exhaust collecting passage 19 and the exhaust guide 20 in the embodiment of FIGS. 10 and 11.
In this example, the lower ends of the two exhaust collecting passages 19 are connected to the exhaust passage 43 of the exhaust guide 20 and fitted into a jointed or integrally formed collar 61, and the two are connected via a rubber hose 62. It is a thing. The rubber hose 62 is hermetically attached by a tightening band 69 having a fixture 63. Further, the cooling jacket 44 on the outer circumference of the exhaust collecting passage 19 is also connected to a collar 66, which is communicated with or integrally formed with the cooling water passage 65 provided in the exhaust guide 20, through a rubber hose 67. The rubber hose 67 is hermetically fixed by a tightening band 69 having a fixture 68.

In such a structure, the cooling water pump 2
The cooling water pressure-fed from 6 (see FIG. 1) is supplied to the cooling water passage 6
5, the jacket 44 on the outer periphery of the exhaust collecting passage 19 is first circulated as described above.

As described above, by connecting the exhaust collecting passage 19 and the exhaust guide 20 via the rubber hose, the face-to-face error of the joint portion is absorbed, and a reliable sealed connection is achieved. Therefore, it is not necessary for the joint surface of the mold to have high processing accuracy, and the processing and assembly can be facilitated. Instead of the rubber hose, another elastic member made of resin or the like or a flexible member may be used. Other configurations and operational effects are the same as those of the embodiment shown in FIGS.

[0040]

As described above, according to the present invention, in the vertically arranged V-type engine, the collecting portion in each bank of the exhaust collecting passage 19 taken out from the cylinder head of each of the left and right banks is temporarily provided on the cylinder block side. After that, the left and right exhaust collecting passages are joined together to form one exhaust pipe, which is connected to the exhaust guide or the exhaust passage in the casing. Therefore, the combined exhaust pipe is located at the center of the outboard motor casing. Since it is arranged in a wide area with a space, a large exhaust pipe cross-sectional area can be secured. As a result, it is possible to improve the engine performance with a compact structure.

Further, in the present invention, in the multi-cylinder V-type engine, since the exhaust passage integrated with the cylinder head is formed inside the banks, the bank included angle is reduced to reduce the engine width and the longitudinal length. The size of the outboard engine can be reduced, and the outboard engine can be made compact. In this case, since the exhaust pipe (exhaust collecting passage) provided between both banks is integrally molded with the cylinder head, the number of parts is reduced, the complexity of parts management is reduced, the manufacturing process is simplified, and the assembly error is caused. This eliminates the risk of causing a reliable product.

Further, in such a structure, the cooling water circulation path is provided inside the bank by first cooling the periphery of the exhaust collecting passage between both banks and then cooling the periphery of the cylinder. The exhaust passage is efficiently cooled, and the heat of the exhaust passage does not cause the cylinder block to be excessively thermally affected and deformed or overheated.

Further, in this case, since the cooling water which has once cooled the exhaust collecting passage and has a substantially uniform proper water temperature is sent around the cylinder, the temperature management and control of the engine are properly performed, and stable combustion is obtained. It becomes advantageous in combustion. Especially in the outboard motor, since the circumference of the cylinder is directly cooled by seawater etc., the water temperature may be too low or the temperature fluctuation may be too large, so it is very difficult to control the temperature of the cooling water.
According to the configuration of the present invention, since the cooling water rises to a substantially stable constant temperature due to exhaust heat and then the periphery of the cylinder is cooled, a stable combustion action can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram of an embodiment of the present invention.

2 is a detailed view of the upper portion of the embodiment of FIG.

FIG. 3 is a detailed view of the central portion of the embodiment of FIG.

FIG. 4 is a detailed view of the lower portion of the embodiment of FIG.

5 is a horizontal sectional view of a main part of the embodiment of FIG.

FIG. 6 is a rear view of the engine portion of the embodiment of FIG.

FIG. 7 is a side view of the intake system of the embodiment of FIG.

FIG. 8 is a front view of the intake system of the embodiment of FIG.

FIG. 9 is a rear view of the engine portion of another embodiment of the present invention.

FIG. 10 is an explanatory diagram of a main part configuration of still another embodiment of the present invention.

11 is a rear view of the engine portion of the embodiment of FIG.

12A and 12B are a longitudinal sectional view and a rear view of a main part of still another embodiment of the present invention.

[Explanation of symbols]

 1: Outboard motor 7: Engine 8: Cylinder head 10: Surge tank 11: Intake passage 18: Exhaust passage 19: Exhaust collecting passage 20: Exhaust guide 22: Exhaust pipe 23: Oil pan 24: Oil strainer 26: Cooling water pump 30a, 30b: Bank 44: Cooling jacket 50: Oil pump

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F02F 1/42 B63H 21/26 E

Claims (6)

[Claims] 1. An exhaust passage of each cylinder is provided toward the inside of a bank arranged in a V shape, and an exhaust collecting passage where the exhaust passages from each cylinder are gathered for each bank is integrated with the cylinder head inside the bank. The exhaust structure of the V-type engine is characterized in that the exhaust collecting passages of each bank are directed to the cylinder block side and then these are joined. 2. The engine is a V-type engine for outboard motors, which is vertically arranged, and a portion where exhaust from all cylinders in a bank in the exhaust collecting passage in each bank is collected,
The exhaust structure for a V-type engine according to claim 1, wherein the exhaust structure is formed at a lower end portion of each bank. 3. The engine is a V-type engine for an outboard motor, which is vertically arranged, and a portion where exhaust from all cylinders in a bank in the exhaust collecting passage in each bank is gathered,
The exhaust structure for a V-type engine according to claim 1, wherein the exhaust structure is formed in an intermediate portion of each bank. 4. A V-type engine in which an exhaust guide is attached to a lower end portion of the engine, wherein exhaust collecting passages of the banks are joined on the engine side and connected to the exhaust guide. An exhaust structure for a V-type engine according to claim 2 or 3. 5. A V-type engine having an exhaust guide attached to a lower end portion of the engine, wherein exhaust collecting passages of each bank are directly connected to the exhaust guide. Alternatively, the exhaust structure of the V-type engine according to Item 3. 6. The exhaust structure for a V-type engine according to claim 5, wherein a hose having elasticity or flexibility is interposed at a connecting portion between the exhaust collecting passage of each bank and the exhaust guide. .