JP2006002680A - Cooling structure of vapor separator for outboard motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a vapor separator for an outboard motor suppressing rise of fuel temperature in a vapor separator tank and securing operability at a time of restart and after start by reducing quantity of vapor produced in the tank. <P>SOLUTION: The vapor separator tank 8 provided near an engine 1, a cover body 9 enclosing the vapor separator tank 8 via a gap, an outer air introducing duct 11 connected to a lower part of the cover body 9 and introducing outer air to the gap, and an exhaust duct 12 connected to an upper part 9 of the cover body and discharging air in the gap to an outside of the cover body 9 are included in a cowling storing the engine 1 of an outboard motor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling structure for a vapor separator for an outboard motor.

  In the outboard motor fuel system, a sub fuel tank called a vapor separator tank is provided in the outboard motor cowling separately from the main fuel tank in the hull. Fuel is supplied from the main fuel tank to the vapor separator tank, and this fuel is pumped to the fuel injection device by a high-pressure fuel pump. Of the fuel pressure-fed to the fuel injection device by the high-pressure fuel pump, the surplus remaining without being injected by the fuel injection device returns to the vapor separator tank via a return passage (see, for example, Patent Document 1).

However, since the conventional vapor separator tank including the vapor separator tank of Patent Document 1 is disposed adjacent to the engine in the outboard motor cowling, the conventional vapor separator tank is likely to receive radiant heat from a high heat engine. Even if the engine is not rotating at high speed, the temperature inside the cowling itself is high during a dead soak in a high temperature period after the engine stops or during a hot hot soak during idle operation. Due to this hot air, the vapor separator tank itself becomes high temperature, and the fuel temperature in the tank rises. Vapor is likely to occur when the fuel temperature rises. As a result, for example, when new fuel is supplied from the main fuel tank to the vapor separator tank at the time of restarting the engine, the new fuel and the high temperature fuel in the vapor separator tank are mixed, and the temperature of the new fuel rises, Increases the amount of vapor. Further, the amount of vapor generated in the tank is further increased by the stirring action in the tank by the return fuel from the return passage. An increase in the amount of vapor generated in the vapor separator tank adversely affects low-speed driving performance during hot soak and restartability and acceleration after dead soak.

JP-A-9-144617

  The present invention considers such a current situation, suppresses an increase in fuel temperature in the vapor separator tank, reduces the amount of vapor generated in the tank, and improves drivability during restart or after starting. An object is to provide a cooling structure for a vapor separator for an outboard motor that ensures the above.

  In order to achieve the above-mentioned object, the invention of claim 1 includes a vapor separator tank provided close to the engine in a cowling that houses the engine of the outboard motor, and the vapor separator tank surrounded by a gap. A cover body that is connected to a lower portion of the cover body and introduces outside air into the gap, and an exhaust duct that is connected to the upper portion of the cover body and discharges air in the gap to the outside of the cover body. An outboard motor vapor separator cooling structure is provided.

  According to a second aspect of the present invention, there is provided a cooling structure for an outboard motor vapor separator according to the first aspect, wherein at least one of the outside air inlet of the outside air introduction duct and the exhaust outlet of the exhaust duct has water from outside the duct. A water repellent filter for preventing intrusion is provided.

  According to a third aspect of the present invention, in the cooling structure for an outboard motor vapor separator according to the first aspect, the exhaust outlet of the exhaust duct is disposed in the vicinity of an intake inlet of a molding air duct provided at the upper portion of the cowling. Features.

  According to a fourth aspect of the present invention, there is provided a cooling structure for an outboard motor vapor separator according to the first aspect, wherein the cover body has a low thermal conductivity lower than that of the material constituting the engine. It is made of a material.

According to a fifth aspect of the present invention, in the cooling structure for an outboard motor vapor separator according to the fourth aspect, the low thermal conductivity material is a resin material.

  According to a sixth aspect of the present invention, in the cooling structure for an outboard motor vapor separator according to the first aspect, the cover body includes an inner cover portion fixed to the engine side, and a vapor separator held by the inner cover portion. It consists of a two-part body of the outer cover that covers the tank.

  According to the first aspect of the invention, by covering the vapor separator tank with the cover body, the temperature increase of the vapor separator tank due to radiant heat from the engine body as a heat source and heat transfer from the surrounding hot air is suppressed, and the vapor separator tank is Can be protected thermally. Further, since there is a gap between the cover body and the vapor separator tank, an air layer is interposed, thereby increasing the heat insulation effect. Since the exhaust duct is connected to the upper part and the outside air introduction duct is connected to the lower part of the cover body, the air in the cover body heated by the heat received by the cover body rises toward the upper exhaust duct by natural convection. As a result, the air taken into the cover body from the outside air introduction duct is efficiently discharged through the exhaust duct. As a result, outside air is always naturally introduced into the cover body to cool the inside. Therefore, the heating of the vapor separator tank and the temperature rise of the fuel in the tank due to hot air from the engine and ambient air are suppressed, and the amount of vapor generated in the vapor separator tank is reduced.

  According to the second aspect of the present invention, the water repellent filter prevents water from entering the outside air introduction duct or the exhaust duct and into the cover body, and can suppress corrosion of these parts.

  According to the invention of claim 3, the duct exhaust passage is efficiently provided in the narrow cowling by installing the exhaust outlet of the exhaust duct in the vicinity of the low-temperature intake inlet of the molding air duct provided at the upper portion of the cowling. With the intake of fresh air into the intake air intake, the air flow of the outside air introduction duct, the cover body, and the exhaust duct by natural convection is promoted, and the cooling action of the cover body itself is improved. In addition, the upper surface of the intake air inlet of the molding air duct has a flood prevention structure that is covered with roofing material, etc., preventing flooding from the exhaust duct outlet without taking special flood prevention measures. can do.

  According to the invention of claim 4, the cover body is formed of a low thermal conductivity material whose thermal conductivity is lower than the thermal conductivity of the material constituting the outboard motor engine, whereby heat insulation from the engine and ambient air is achieved. Increases nature. Moreover, when it fixes to a cover body and an engine or other high temperature members, the heat conduction from an engine etc. can be suppressed low and the temperature rise of the fuel in a tank can be suppressed.

  According to the invention described in claim 5, by using the low thermal conductivity material as a resin, a cover body having a desired shape can be easily obtained by molding, and weight reduction of the outboard motor itself can be achieved.

  According to the sixth aspect of the present invention, when the engine is assembled, the inner cover portion of the cover body divided into two is fixed to the engine, the vapor separator tank is fixed to the inner cover portion, and then the outer cover portion is covered. The cover body can be easily attached. It can also be easily removed during maintenance.

FIG. 1 is a block diagram of an outboard engine fuel supply system according to the present invention.
In the engine 1 of the outboard motor, an injector 6 is provided in an intake port 34 formed in a cylinder head of each cylinder or an intake manifold 33 connected thereto. The fuel tank 3 provided in the hull (not shown) is connected to the vapor separator tank 8 in the outboard motor via the fuel pipe 21. A prime (manual) pump 22, a filter 23 and a low pressure pump 24 are interposed in the fuel pipe 21, and a check valve 25 for preventing fuel backflow is juxtaposed with the low pressure pump 24. The prime pump 22 is provided in the ship, and the filter 23 and the low pressure pump 24 are provided in the outboard motor. Inside the vapor separator tank 8, a float 26 for keeping the fuel in the tank constant and a high-pressure pump 27 for pumping the fuel in the tank to the injector 6 are provided. When the fuel drop is detected by the float 26, the low pressure pump 24 is operated to supply the fuel 20 in the fuel tank 3 to the vapor separator tank 8. The fuel is manually supplied to the vapor separator 8 by the prime pump 22 when the low-pressure pump 24 fails or otherwise. The high pressure pump 27 supplies fuel to each injector 6 (only one injector is shown in the figure) via the fuel pipe 28 and the delivery pipe 30. A plurality of injectors 6 are attached to one linear delivery pipe (fuel rail) 30. A pressure regulator 29 is provided at the downstream (exit side) end of the delivery pipe 30 to keep the fuel injection pressure constant. The fuel that exceeds the specified pressure is returned from the pressure regulator 29 to the vapor separator tank 8 through the return pipe 31. The return pipe 31 is provided with a fuel cooler 32. Cooling water is supplied to the fuel cooler 32 as a heat exchange medium to cool the return fuel.

An intake silencer 2 is connected to the intake manifold 33 via an intake pipe 4 to intake outside air. A throttle body 60 having a throttle valve 35 is provided inside the intake pipe 4. The opening degree of the throttle valve 35 is detected by a throttle sensor 36 and input to an ECU (electronic control unit) 37. An intake pressure / intake temperature sensor 38 for detecting the pressure and temperature of intake air taken in via the silencer 2 is attached to the intake pipe 4, and the detected information is also input to the ECU 37. In the intake passage, an auxiliary intake pipe 39 for intake control during idling opens on the downstream side of the throttle body 60, and an idle speed control (ISC) valve 40 controlled by the ECU 37 is interposed in the intake pipe 39. It controls the intake amount during idling.

The fuel vapor generated in the vapor separator tank 8 is introduced into the silencer 2 and the canister 41. The fuel vapor introduced into the silencer 2 is supplied as intake air to the engine 1 through the intake pipe 4 together with outside air. When idling, fresh air is introduced into the intake pipe 4 from the canister 41 via the ISC 40. In FIG. 1, 42 is a check valve, and 43 is an orifice (throttle). In addition to the various sensors described above, the ECU 37 is connected to a machine temperature sensor 44 that detects the temperature of the engine cooling water, a pulsar coil 45 that detects the engine rotation angle, and the like. The ECU 37 is driven by a power source from the battery 46. Reference numeral 47 denotes an alternator (generator) that charges the battery 46 and is attached to the crankshaft of the engine 1. 48 is a fuse and 49 is a main relay.

The present invention aims at thermal protection of the vapor separator tank 8 in such a fuel supply system.

FIG. 2 is a side view of an outboard motor to which the present invention is applied.
As shown in FIG. 2, the outboard motor 50 is attached to a stern plate of a hull (not shown) by a clamp bracket 51. The outboard motor 50 includes a cowling 52 that houses the engine 1 at an upper portion thereof. The cowling 52 includes a top cowling 53 and a bottom cowling 54. A propulsion device (not shown) is provided below the outboard motor 50. The propulsion device includes a bevel gear mechanism that transmits rotation of a drive shaft connected to a vertically arranged crankshaft (not shown) of the engine 1 to a horizontal propeller shaft (not shown), a forward / reverse switching clutch, and the like. A propeller 56 is attached to the end of the propeller shaft. The lower part of the outboard motor 50 is continuous with the bottom cowling 54 and is covered with an upper casing 57 and a lower casing 58. The top cowling 53 is detachably attached to the bottom cowling 54.

For example, a V-type 6-cylinder engine 1 is accommodated in the cowling 52. The engine 1 is mounted and fixed on a guide exhaust (not shown) covered with a bottom cowling 54.

FIG. 3 is a horizontal sectional view of the cowling portion of the outboard motor.
The intake silencer 2 described above is provided at the front of the engine 1. The intake silencer 2 is provided with three intake pipes 4 on the left and right sides (only one is shown because it is viewed from above), and communicates with the cylinder head 5 of each cylinder. A throttle body 60 is mounted in the middle of each intake pipe 4, and an injector 6 is provided facing the intake manifold 33 on the downstream side.

A drive shaft (not shown) is connected to the lower end of the crankshaft 7 of the engine 1, and the drive shaft extends downward in the upper casing 57 (FIG. 2), via a bevel gear (not shown) in the lower casing 58. Then, the propeller 56 is driven.

As described above, the vapor separator tank 8 is provided in the middle of the fuel supply system connecting the fuel tank 3 (FIG. 1) and the injector 6 in the hull. In this example, the vapor separator tank 8 is attached to the side surface of the left front portion of the crankcase of the engine 1. The vapor separator tank 8 is covered with a cover body 9.

FIG. 4 is a longitudinal sectional view of the engine as seen from the front around the vapor separator tank.
As shown in FIG. 4, the vapor separator tank 8 is covered with a cover body 9 at the lower portion that stores the liquid fuel. The cover body 9 is formed of a material having a low thermal conductivity (for example, a resin material) as compared with an engine constituent material (aluminum alloy) of a cast body, and includes an inner cover member 91 fixed to the engine 1 body, It is a two-part structure composed of an outer cover member 92 attached to the member 91 through fastening means such as bolts (not shown).

The vapor separator tank 8 is accommodated in the internal space 93 of these members 91 and 92 in an integrated state. The vapor separator tank 8 is fixed to the boss 95 protruding from the side wall 94 of the inner cover member 91 via a bolt 96 inside the cover body 9. The vapor separator tank 8 fixed to the inner cover member 91 leaves a gap for the outside air circulation described later between the side wall 94 and the vapor separator tank 8. With the vapor separator tank 8 fixed, the outer cover member 92 is attached to cover the vapor separator 8 from the outside. A gap is also formed between the outer cover member 92 and the vapor separator tank 8. A seal member 82 is interposed between the upper end of the cover body 9 and the outer peripheral flange 81 of the vapor separator tank 8 to close the upper end opening of the cover body 9. An outside air introduction port 97 is formed to project downward at the lower part of the inner cover member 91, and an exhaust port 98 is formed to project upward at the upper part.

An outside air introduction duct 11 that guides air outside the cowling 52 to the inside of the cover body 9 is provided in the outside air introduction port 97 provided in the cover body 9, and air inside the cover body 9 is discharged to the outside at the exhaust port 98. The exhaust ducts 12 are connected to each other. In addition, a water repellent filter 13 is attached to the outside air inlet of the outside air introduction duct 11 to prevent water from entering the duct 11. The water repellent filter 13 may be similarly attached to the exhaust outlet at the end of the exhaust duct 12.

FIG. 5 is a cowling side sectional view showing the positional relationship between the above-described outside air introduction duct 11 and exhaust duct 12 and the vapor separator tank 8. FIG. 6 is a cowling plan view showing the same positional relationship. 5 and 6, the water repellent filter 13 attached to the outside air introduction duct 11 is omitted.

As shown in FIG. 5, the inner cover member 91 (FIG. 4) of the cover body 9 is fixed to the engine 1 by four bolts 9a. The vapor separator tank 8 is fixed to the inner cover member 91 by three bolts 96. The outer cover member 92 (FIG. 4) is fixed to the inner cover member 91 by seven bolts 9b. An outside air intake at the end of the outside air introduction duct 11 opens into the bottom cowling 54. Preferably, the bottom cowling is opened at a position below.

On the other hand, the exhaust duct 12 is arranged by bending an auxiliary machine (not shown) on the outer peripheral portion of the engine in the top cowling 53 from the exhaust port 98 of the cover body 9. The exhaust outlet at the end of the exhaust duct 12 is disposed close to the intake intake 15 of the molding air duct 14 disposed in the upper part of the engine 1. The molding air duct 14 has two intake inlets 15 commonly called “ents” and is formed at the upper part of the top cowling 53 to constitute an intake intake into the cowling. As shown in FIG. 6, in this example, the exhaust outlet 12 a at the end of the exhaust duct 12 is disposed below the opening 15 a of one of the inlets (intake intake) 15.

  The exhaust duct 12 is arranged so that there is no lower portion in the middle from the exhaust port 98 to the exhaust port 12a. Thereby, the flow of air becomes smooth and water is prevented from accumulating in the duct.

FIG. 7 is an external perspective view of the molding air duct 14 and the top cowling 53.

As shown in the figure, the molding air duct 14 is attached to the upper inside of the top cowling 53 via a plurality of bolts 16a and nuts 16b (only one is shown in FIG. 7). Two intake intakes 15 are formed on the upper surface of the molding air duct 14. An opening 17 is formed behind the top cowling 53. Outside air flows into the cowling through the opening 17. The upper part of the intake port 15 is covered with a roof cowl 53a integrated with the top cowling 53 (see FIG. 5). Further, the opening 15 a of the intake intake 15 is formed at a position higher than the opening 17 of the top cowling 53. Thereby, the invasion of water from the intake port 15 into the cowling is suppressed. Reference numeral 18 denotes a waterproof packing.

The operation of the cooling structure of the vapor separator tank configured as described above will be described with reference to FIGS. 4 to 6 again.

As described above, according to this embodiment, the vapor separator tank 8 is protected from the engine 1 by the cover body 9. As a result, heat radiation from the engine 1 (heat source) and heat transfer from the high-temperature air in the cowling are blocked by the cover body 9 during dead soak and hot soak, and heat transfer to the vapor separator tank 8 is suppressed. At this time, since the inner cover member 91 of the cover body 9 is directly fixed to the engine 1 in this embodiment, the heat of the engine 1 is directly transferred to the inner cover member 91. However, since the cover body 9 is made of resin, the thermal conductivity is small, and the cover body 9 does not heat up significantly. Further, an air layer is interposed between the vapor separator tank 8 and the side wall 94 of the inner cover member 91 as described above. This air layer acts as a heat insulating material, and the temperature rise of the vapor separator tank 8 is suppressed. Furthermore, a convection action is obtained by this air layer, and the vapor separator tank 8 is efficiently cooled in combination with the action of the outside air introduction duct 11 and the exhaust duct 12 described above. That is, the heated heat from the inner cover member 91 is transmitted to the air layer and warms the air layer around the vapor separator tank 8. The air layer becomes lighter due to the decrease in specific gravity accompanying the temperature rise, rises inside the cover body 9 by convection, flows into the exhaust duct 12 through the exhaust port 98, and finally reaches the top cowling from the vicinity of the molding air duct 14. 53 is discharged to the outside. As a result, natural convection (upward airflow) as indicated by an arrow in the figure is generated in the cover body 9, and the cowling 52 passes through the outside air introduction duct 11 attached to the lower side of the cover body 9 with the occurrence of this convection. External cold air is introduced into the cover body 9. As a result, the air whose temperature is constantly increased in the cover body 9 is replaced with newly introduced cold air, and the rise in the fuel temperature in the vapor separator tank 8 and the tank is suppressed. Furthermore, in the present embodiment, the tip of the exhaust duct 12 serving as the outlet of the heated air in the cover body 9 is disposed close to the intake air intake 15 of the molding air duct 14. Along with the intake of air, a large negative pressure acts on the outlet of the exhaust duct 12 to promote the air flow in the exhaust duct 12 (see arrow in FIG. 6). Thereby, in the vapor separator cooling structure, the air flow of the outside air introduction duct 11 → the cover body 9 → the exhaust duct 12 is promoted, and the cooling action of the cover body 9 to the vapor separator tank 8 is improved.

Thus, according to the present embodiment, in addition to protecting the vapor separator tank 8 with the cover body 9 through the air layer, the vapor separator tank 8 can be protected by always introducing outside air into the cover body 9. The increase in the fuel temperature inside the tank 8 can be suppressed, and the amount of vapor generated in the tank 8 can be kept low during engine restart, acceleration after restart, hot soak, and the like. Further, the vapor separator cooling structure of the present embodiment is provided with an outside air inlet at the lower side of the cover body 9 and an exhaust port at the upper side, utilizing the rising air flow generated inside the cover body 9 to heat the vapor separator tank 8. Since it suppresses and does not depend on mechanical / electrical driving means such as a forced fan, the structure is simple and the manufacturing cost can be kept low.

Further, in this embodiment, since the water repellent filter 13 is attached to the outside air introduction duct 11, it is possible to prevent water from entering the inside of the duct 11 and the inner space of the cover body 9, and corrosion of the internal parts of the cowling due to seawater or the like can be prevented. Can be prevented. Further, the water repellent filter 13 may be attached to the exhaust outlet on the exhaust duct 12 side.

Although the present invention has been described above, the cooling structure of the outboard motor vapor separator according to the present invention is not limited to the illustrated embodiment. For example, although the cover body 9 has been described as covering the lower half of the vapor separator tank 8 in the embodiment, the shape may be complicated, but the entire tank may be covered. In the case of this embodiment cover body 9 covering the lower half, the cover shape is simple and mass production is easy as compared to the case of covering the whole. In addition, since the tank portion covered with the cover body 9 is a portion where the liquid fuel is accumulated, an effect of sufficiently suppressing heat transfer to the internal fuel can be expected without covering the whole.

Further, in the present embodiment, the inside of the cover body 9 is structured to communicate with the outside air via the outside air introduction duct 11 and the exhaust duct 12, but as a modification, the duct bodies 11 and 12 are eliminated and the cover body is removed. As a closed structure, heat from a high temperature field in the cowling may be insulated by an air layer in the sealed space by a so-called thermos effect, and an increase in fuel temperature in the vapor separator tank 8 may be suppressed.

  As an application example of the present invention, it can be effectively applied as a cooling structure not only to an outboard motor but also to an engine having a vapor separator tank.

The block diagram of the fuel supply system of an outboard motor. 1 is a side external view of an outboard motor according to an embodiment of the present invention. 1 is a cross-sectional view of an outboard motor according to an embodiment of the present invention. The longitudinal cross-sectional view seen from the vapor separator tank and cover body which concern on the Example of this invention. The longitudinal cross-sectional view of the outboard motor which shows the vapor separator cooling structure by this invention. FIG. 6 is a cross-sectional view of the outboard motor showing the vapor separator cooling structure of FIG. 5. The exploded perspective view of a top cowling part.

Explanation of symbols

1: engine, 2: intake silencer, 3: fuel tank, 4: intake pipe,
5: Cylinder head, 6: Injector, 7: Crankshaft,
8: vapor separator tank, 9: cover body, 9a, 9b: bolt,
11: Outside air introduction duct, 12: Exhaust duct, 12a: Exhaust outlet,
13: Water repellent filter, 14: Molding air duct,
15: intake port, 15a: opening, 16: bolt,
17: Opening, 18: Waterproof packing, 20: Fuel,
21: Fuel pipe, 22: Prime (manual) pump, 23: Filter,
24: low pressure pump, 25: check valve, 26: float,
27: high pressure pump, 28: fuel pipe, 29: pressure regulator,
30: Delivery pipe, 31: Return pipe, 32: Fuel cooler,
33: intake manifold, 35: throttle valve,
36: Throttle sensor, 37: ECU, 38: Intake pressure / intake temperature sensor,
39: Intake pipe, 40: Idle speed control (ISC) valve,
41: canister, 42: check valve, 43: orifice,
44: Machine temperature sensor, 45: Pulsar coil, 46: Battery,
47: Alternator, 48: Fuse, 49: Main relay,
50: Outboard motor, 51: Clamp bracket, 52: Cowling,
53: Top cowling, 54: Bottom cowling, 55: Propulsion device,
56: Propeller, 57: Upper casing, 58: Lower casing,
81: outer peripheral flange, 82: seal member, 91: inner cover member,
92: Outer cover member, 93: Space, 94: Side wall, 95: Boss,
96: Bolt, 97: Outside air introduction port, 98: Exhaust port.

Claims (6)

A vapor separator tank provided close to the engine in the cowling that houses the engine of the outboard motor;
A cover body surrounding the vapor separator tank via a gap;
An outside air introduction duct connected to the lower part of the cover body and introducing outside air into the gap;
A cooling structure for a vapor separator for an outboard motor, comprising an exhaust duct connected to an upper portion of the cover body and exhausting the air in the gap to the outside of the cover body. 2. The outboard motor according to claim 1, wherein a water repellent filter for preventing water from entering from outside the duct is provided at least one of an outside air inlet of the outside air introduction duct and an outlet of the exhaust duct. Cooling structure for vapor separator.   2. The cooling structure for an outboard motor vapor separator according to claim 1, wherein an exhaust outlet of the exhaust duct is disposed in the vicinity of an intake inlet of a molding air duct provided at an upper portion of the cowling.   2. The cooling structure for an outboard motor vapor separator according to claim 1, wherein the cover body is formed of a low thermal conductivity material whose thermal conductivity is lower than that of a material constituting the engine. .   5. The cooling structure for an outboard motor vapor separator according to claim 4, wherein the low thermal conductivity material is a resin material. 2. The ship according to claim 1, wherein the cover body is composed of a two-part body comprising an inner cover portion fixed to the engine side and an outer cover portion covering the vapor separator tank held by the inner cover portion. Cooling structure of vapor separator for external machine.

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