JP3726925B2 - Intake structure of 4-cycle V engine for outboard motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake structure for an engine, and more particularly, to an intake structure for a 4-cycle V-type engine for an outboard motor that is arranged vertically.
[0002]
[Prior art]
A 2-cycle V-type engine has been put to practical use as an outboard motor engine, and a 4-cycle V-type engine is disclosed in Japanese Patent Laid-Open No. 6-264757.
[0003]
According to the publicly known technology described in this publication, in a 4-cycle V-type engine for an outboard motor arranged vertically, an exhaust port is provided inside each bank arranged in a V-shape, and an exhaust passage communicating with the exhaust port is provided in the engine. A compact V-type engine structure is achieved by connecting to the exhaust pipe below and arranging an intake port and an intake system communicating with the outside on each bank.
[0004]
In such outboard motors, starter motors, alternators or engine accessories such as fuel filters, pumps, and vapor separators, which are essential components for driving the engine, are limited in the cowling that houses the engine. It is necessary to store in an extremely compact space. In addition, it is important to improve the reliability of operation, especially due to the special circumstances of operation at sea, and it is important to achieve stable operation at all times by performing uniform combustion control by performing particularly stable air-fuel ratio control for each cylinder. is necessary.
[0005]
[Problems to be solved by the invention]
Accordingly, the object of the present invention is to further improve the V-type engine described in the above publication, to effectively use the space, to effectively store the engine accessories, to obtain a more compact structure, and to obtain a uniform and stable air It is to realize an intake pipe structure of a V-type engine in which combustion is achieved at a fuel ratio.
[0006]
[Means for Solving the Problems]
To achieve the above object, the present invention, a vertical left and right banks inside the exhaust passage of the V-type engine is provided, an intake passage provided in the bank outside left and right surge tank connected to the engine front side to the respective intake passages of the left and right A throttle body facing down is provided at the center of the intake pipe that connects the left and right surge tanks. An alternator is installed in the space above the throttle body, and a heat shield is placed between the alternator and the throttle body. The throttle body is attached to the lower side of the intake pipe via the heat shield plate, and a starter motor is disposed in the upper space of the intake passage. The intake structure of the type engine is provided.
[0007]
In such a configuration, the engine auxiliary equipment can be disposed between the intake surge tanks provided on the left and right 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, if an engine accessory such as an alternator that is particularly heavy and heat-generating is arranged on the front side of the engine, the weight balance will be appropriate when mounted on the stern as an outboard motor, and the shape will also be balanced. . In addition, since the throttle body is attached to the intake pipe via a heat shield, heat from a heat-generating engine accessory such as an alternator provided on the upper side of the intake pipe is blocked to prevent the intake air from becoming hot and empty. It is possible to prevent a decrease in output due to a change in the fuel ratio.
[0008]
In addition, since the engine accessory is arranged in the upper space on the front side of the engine, the waterproof property can be enhanced and the water resistance against the engine accessory can be improved.
[0009]
Further, since the throttle body is provided in the central portion of the intake passage between the left and right surge tanks, the intake pipe length from the intake inlet to both banks becomes equal, and the air-fuel ratio of each cylinder in the bank can be controlled uniformly.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment, an alternator (generator) is disposed in the space above the throttle body.
[0011]
In another preferred embodiment, the surge tank side of the intake pipe that communicates each cylinder of the left and right banks and the surge tank is gathered at the center in the vertical direction and connected to the surge tank.
[0012]
In yet another preferred embodiment, the left and right banks are each composed of a plurality of cylinders, and the intake pipes at the center of the plurality of intake pipes are vertically moved so that the lengths of the intake pipes from each cylinder to the surge tank are equal. It is characterized in that an intake passage route is constructed by inflating outside the intake pipe.
[0013]
【Example】
FIG. 1 is a block diagram of the main part of an outboard motor equipped with a 4-cycle 6-cylinder vertical V-type engine according to an embodiment of the present invention. 2 to 4 are detailed configuration diagrams of an upper portion, a central portion, and a lower portion of the outboard motor of FIG.
[0014]
The outboard motor 1 is clamped to a hull plate 3 at the rear of the hull via a bracket 2 and is mounted rotatably around a tilt shaft 2a by a hydraulic cylinder (not shown) or manually. The outboard motor 1 is further rotatable around the swivel shaft 4 and is mounted so as to be steerable.
The outside of the outboard motor 1 is covered with a cowling 5 including an upper cowling 5a and a lower cowling 5b, which are engine storage portions, and an upper casing 6a and a lower casing 6b below the cowling 5. A 6-cylinder V-type engine 7 is housed in the cowling 5 in a vertically placed manner in which the axis 13 (FIG. 1) of the crankshaft 52 (FIG. 2) is arranged in a substantially vertical direction 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 composed of three vertically arranged cylinders of a six-cylinder V type. Each intake passage 11 branches from a surge tank 10, and an intake pipe 9 communicating with outside air is connected to the surge tank 10.
[0015]
A throttle body 62 equipped with an intake air amount adjusting butterfly valve or the like is disposed on the intake pipe 9 so as to face downward (with the air intake port facing downward). The throttle body 62 is attached to the intake pipe 9 via a heat shield plate 95. This heat shield plate 95 blocks heat from the alternator 73 provided on the upper side of the intake pipe 9 to prevent the intake air from becoming hot and prevent a decrease in output due to fluctuations in the air-fuel ratio. It functions as a plate.
[0016]
The flywheel 12 is mounted on the upper portion of the engine 7 by being fastened and fixed by a nut 51 coaxially with the crankshaft 52 (FIG. 2). A pulley 58 (FIG. 2) is attached to the lower portion of the flywheel 12 and is connected to an alternator 73 via a belt 98. The upper portion of the flywheel 12 is covered with a flywheel cover 57 (FIG. 2). A valve cam drive chain 60 is attached to the lower crankshaft 52 of 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.
[0017]
A head 53 of the drive shaft 14 is connected and fixed 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, or 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. It is transmitted to the shaft 16. A propeller 17 is attached to the rear end portion 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 and downward along the cylinder block 31 (FIG. 5) of each cylinder of the engine 7.
[0018]
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. An exhaust passage 43 is formed substantially at the center of the exhaust guide 20. The exhaust collecting passages 19 of the left and right banks described above communicate 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 continue to the exhaust passage 43. The exhaust pipe 22 is disposed facing the main exhaust chamber 21 in the upper casing 6a. Exhaust gas from the engine 7 is introduced into the main exhaust chamber 21 through the exhaust passages 18, the exhaust collecting passages 19, the exhaust passages 43, and the exhaust pipes 22, and is further guided downward to form an annular space around the propeller shaft 16. And is discharged into the water from the rear end.
[0019]
An oil pan 23 is provided in the upper casing 6a below the exhaust guide 20, and an oil strainer 24 is provided therein. An oil pump 50 is attached to the lower end of the crankshaft 52 (FIG. 2) (the head 53 of the drive shaft 14). The oil in the oil pan 23 is sucked by the oil pump 50 through the oil strainer 24 and is pumped to the engine side through the main oil passage 55 (FIGS. 1 and 2). A branch oil passage 56 is formed from the main oil passage 55 so as to communicate with each cylinder and the valve camshaft. 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.
[0020]
The cooling water is taken from the water intake 25 by a cooling water pump 26 (FIGS. 1 and 4) connected to the drive shaft 14. As shown by the arrows in the figure, the cooling water is guided upward, and first, the exhaust collecting passage 19 is cooled from the lower side through the exhaust cooling water passage 44 formed around the exhaust collecting passage 19, After being introduced into the upper part of the oil cooling water passage 85 adjacent to the main oil passage 55 from the upper portion and descending to cool the main oil passage 55, it is further introduced into the cylinder head and cylinder block to cool the periphery of the cylinder. Thereafter, the system is divided into A and B2 systems. One system cools the periphery of the oil pan 23 and is discharged into the water, and the other system passes through the jacket around the exhaust pipe 22 and enters the exhaust in the main exhaust chamber 21. It is discharged, merges with the exhaust gas, passes through the periphery of the propeller shaft 16 together with the exhaust gas, and is discharged into the water from its rear end (see FIG. 3). By flowing the cooling water through such a path, not only the exhaust collecting passage 19 and the periphery of the cylinder, but also the main oil passage 55 and the oil pan 23 can be cooled. Even when 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 kept at an appropriate temperature. Further, when 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 keeps it at an appropriate temperature. Be drunk.
[0021]
A pressure valve for discharging the cooling water when the pressure exceeds a predetermined pressure is provided at a portion of the water channel between the exhaust cooling water channel 44 and the oil cooling water channel 85 immediately after the exhaust collecting passage 19 is cooled. Further, at a suitable position of the water channel of such a cooling system, a thermostat that shuts off the water channel including the cooling water channel 85 adjacent to the main oil passage 55 when the temperature of the engine 7 becomes a predetermined temperature or less, and a water flow temperature. A control valve that adjusts the amount of water accordingly is provided.
[0022]
When the engine rotates, as described above, the cooling water pump directly connected to the crankshaft rotates to circulate the cooling water. If the engine temperature is low at this time, the cooling water system is closed by the thermostat while the pump is rotating, and the pressure rises. This pressure rise is released with a pressure valve. By providing this pressure valve at the upper end of the exhaust cooling water passage 44, only the exhaust is always 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.
In addition, when the thermostat is opened by the action of the control valve, a large amount of low-temperature cooling water circulates suddenly to prevent the engine from being cooled rapidly and to prevent unstable combustion due to sudden temperature changes. can do. This control valve controls the flow rate according to the valve opening area of the thermostat and the water temperature.
[0023]
FIG. 5 is a horizontal cross-sectional view of the 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 portion. The engine 7 is composed of two banks 30a and 30b which are arranged vertically by three cylinders provided in a V shape on both left and right sides obliquely rearward from the crankshaft 52, and a cylinder block 31 is provided in the cylinder head 8 of each cylinder of each bank. Are joined, and each cylinder block 31 is fixed to the crankcase 74. A crankcase 74 that accommodates the crankshaft 52 is assembled and fixed to the cylinder block 31 in a V-shaped arrangement by bolts 75 (only one is shown in the figure) provided at appropriate multiple locations. A starter motor 72 for rotating the flywheel 12 at the start is provided on the left outer side (lower side in the drawing) of the crankcase 74. A generator (alternator) 73 that rotates together with the crankshaft 52 is provided above the intake pipe 9 between the left and right surge tanks 10.
[0024]
In the space between the left and right banks on the back side of the engine, a vapor separator 81 having a high pressure pump and a regulator, a low pressure pump 86 and a filter 87 (FIG. 6) are provided. The vapor separator 81 is configured such that 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 to the left and right banks of the engine via a supply path 88. A fuel passage (delivery pipe) 89 extending upward along the line is raised and supplied to an injector 38 provided in each cylinder head 8. The left and right fuel passages 89 are connected to the horizontal communication passages 90 at the upper ends, and the left and right communication passages 90 merge at the center and are connected to the vapor separator 81 via the return passage 92. A pressure regulator (relief valve) 91 is provided at this joining position.
[0025]
In this embodiment, the fuel is supplied from the lower side of each bank as two separate pipes from the high pressure pump of the vapor separator 81 to the left and right banks, and after passing through the injectors 38 of each bank, the fuel joins at the upper side of the bank. One system is returned to the vapor separator 81 via the pressure regulator 91.
As described above, a filter, a low pressure pump, a vapor separator, a fuel pipe, and the like disposed in the space between the V banks on the rear side of the engine may be assembled in advance to form a module to form an integrated fuel system unit. By constructing a module of such an integrated unit and laying it out, the assemblability is improved, maintenance and maintenance can be facilitated, and parts management is facilitated.
[0026]
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. The injector 38 is mounted in the middle of the intake passage 35 of each cylinder, and an intake valve 36 is mounted on the intake port at the end of the intake passage. The intake valve 36 has a valve lifter 77 at the upper end of the valve shaft that is pressed against a spring 78 by a cam (not shown) mounted on a cam shaft 37 that rotates in synchronization with the crankshaft 52. And opens and closes in synchronization with the rotation of the crankshaft 52.
[0027]
A cylinder sleeve 70 made of cast iron or the like is press-fitted into the inner surface of the cylinder block 31 made of aluminum alloy in order to make the piston 34 slide smoothly. An exhaust passage 18 is formed in the cylinder head 8 of each cylinder, and an exhaust valve 39 is attached to the exhaust port at the end thereof. Each exhaust valve 39 is opened and closed at a predetermined timing by a cam mounted on the cam shaft 40 in the same manner as the intake valve 36. A hole for attaching a spark plug is formed at the center of each cylinder head 8. As shown in the figure, the three exhaust passages 18 of each bank are formed in the cylinder head 8 obliquely forward inside the left and right banks 30a and 30b. An exhaust cooling water passage 44 is formed around the exhaust collecting passage 19 where the six exhaust passages 18 of both banks gather. As described above, the cooling water sent from the cooling water pump 26 passes first, The exhaust collecting passage 19 is first cooled.
[0028]
As shown in FIG. 6, the exhaust collecting passage 19 has a configuration in which exhausts of all six cylinders of both banks gather at the lower end thereof, for example, # 1 in the right bank, # 2 in the left bank, and # 3 in the right bank. The exhausts of the left bank # 4, the right bank # 5, and the left bank # 6 are joined sequentially from the top, and all exhausts are collected at the lower end. The collected exhaust communicates with the exhaust passage 43 of the exhaust guide 20.
[0029]
7 and 8 are a side view and a front view, respectively, showing the intake system portion of the above embodiment. As shown in the drawing, two intake surge tanks 10 and 10 are provided corresponding to the left and right banks, and an intake pipe 9 is connected to the upper part of both surge tanks 10. As described above, the throttle body 62 for adjusting the intake air amount is attached to the lower side of the center portion of the intake pipe 9 via the heat shield plate 95. Three intake passages 11 are branched from each surge tank 10 and connected to intake passages 35 (FIG. 5) of three cylinders arranged vertically in each bank. The three intake passages 11 connecting the surge tank 10 and each cylinder have a central intake passage in order to equalize the intake passage length and equalize the air-fuel ratio in each cylinder to uniformly control the combustion state. Is inflated outward. That is, the intake passage 11 shown in the hatched cross section of FIG. 5 shows two upper and lower intake passages, and the outward intake passage 11 shown in the white cross section without hatching shows the central intake passage. With such a configuration, the length of the intake passage 11 for each cylinder is equalized, and the air-fuel ratio in each cylinder is made equal to obtain a uniform combustion action.
[0030]
As shown in the figure, the three intake passages 11 of the three cylinders of each bank are gathered at the center in the vertical direction and connected to the surge tank 10. With this configuration, a space is formed above and below the intake passage, and various engine accessories can be arranged in this space. In the embodiment, the starter motor 72 is laid out in the upper space. It is also possible to appropriately lay out relays, vapor separators, and other engine accessories in the upper space and the lower space.
In addition, by collecting the three-cylinder intake passages 11 in the center and connecting them to the surge tank 10 in this way, the surge tank outlet position (connection position) for each cylinder becomes substantially the same for each cylinder, and the throttle body 62 As the distances become equal, there is no air-fuel ratio difference between cylinders, and uniform and stable operation control is achieved.
[0031]
【The invention's effect】
As described above, in the present invention, exhaust pipes are provided inside the left and right banks of the vertical V-type engine, intake pipes are provided outside the banks, and surge tanks communicating with the left and right intake pipes are provided on the left and right sides of the front side of the engine. Provided separately, a downward throttle body is provided below the center of the intake passage communicating with the left and right surge tanks. An engine accessory is provided in the space above the throttle body, and the engine accessory and the throttle body are shielded. Because the heat plate is installed, engine auxiliary equipment can be placed between the intake surge tanks provided on the left and right of the front side of the engine, space is effectively used, a compact structure is obtained, and the throttle body is also a heat shield plate 95, it is attached to the intake pipe 9 through the heat sink, so that heat from the exothermic engine auxiliary equipment such as an alternator provided on the upper side of the intake pipe is cut off. To prevent high temperature of the intake air can be prevented output reduction due to fluctuations in the air-fuel ratio. In this case, if a heavy engine accessory such as an alternator is disposed on the front side of the engine, the weight balance becomes appropriate when mounted on the stern as an outboard motor, and the shape is also well balanced. In addition, since the engine accessory is arranged in the upper space on the front side of the engine, the waterproof property can be enhanced and the water resistance against the engine accessory can be improved.
[0032]
Further, since the throttle body is provided in the central portion of the intake passage between the left and right surge tanks, the intake pipe length from the intake inlet to both banks becomes equal, and the air-fuel ratio of each cylinder in the bank can be controlled uniformly.
[Brief description of the drawings]
FIG. 1 is a configuration explanatory diagram of an example of an outboard motor to which the present invention is applied.
FIG. 2 is a detailed view of an upper portion of the outboard motor of FIG.
FIG. 3 is a detailed view of a central portion of the outboard motor of FIG.
4 is a detailed view of a lower portion of the outboard motor of FIG. 1. FIG.
5 is a horizontal cross-sectional view of a main part of the outboard motor of FIG. 1. FIG.
6 is a rear view of the 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.
[Explanation of symbols]
1: Outboard motor, 2: Bracket, 2a: Tilt shaft, 3: Ship 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: Axle, 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, 23: 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: Cam shaft, 38: Inji Kuta, 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, 60: Chain, 62: Throttle body, 70: Cylinder sleeve, 72: Starter motor, 73: Alternator, 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, 95 :Heat shield plate

Claims (3)

Vertical provided left and right banks inside the exhaust passage of the V-type engine is provided with a suction passage to the bank outside, respectively separately provided surge tank connected to the left and right engine front to each intake passage of the left and right, communicating the left and right surge tanks A throttle body facing downward is provided at the center of the intake pipe, an alternator is provided in the space above the throttle body, and a heat shield is disposed between the alternator and the throttle body ,
The throttle body is attached to the lower side of the intake pipe via the heat shield plate,
An intake structure for an outboard motor 4-cycle V-type engine, wherein a starter motor is disposed in an upper space of the intake passage . 2. The outboard motor 4 according to claim 1 , wherein the surge tank side of the intake passage connecting the cylinders of the left and right banks and the surge tank is gathered at a central portion in the vertical direction and connected to the surge tank. Cycle V engine intake structure. Left and right banks is made a plurality of cylinders, so that the length of the intake passage from each cylinder to the surge tank equals the intake passage inflatable outwardly to an intake passage of the central portion from the upper and lower intake passages of the plurality of intake passages 3. The intake structure for an outboard motor for a 4-cycle V-type engine according to claim 2, wherein a path is formed.

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