JPH07305641A - Throttle valve device of engine for outboard motor - Google Patents

Abstract

PURPOSE:To lower the manufacturing cost of the throttle valve device of an engine for an outboard motor as well as to simplify the structure thereof with respect to such a matter that a change of intake air quantity relative to the opening change of a throttle valve when the throttle valve is low opened, is lowered. CONSTITUTION:Holes to flow air during an idle operating period are opened to the valve elements 19 of throttle valves 17 at every cylinder. The structure of the throttle valve device of an engine for an outboard motor is built up in such a way that the peripheries of the valve elements 19 are oppositely in contact with the inner walls of intake passes 14 approximately through the whole circumferences thereof when the throttle valve 17 is under fully closing condition. Each pass to flow the air during the idle operation period is not necessary to be provided to each throttle body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve device for an outboard engine used when electronically controlling an outboard engine by determining an intake air amount based on a throttle valve opening. .

[0002]

2. Description of the Related Art Conventionally, in an outboard motor configured so that the engine is electronically controlled, the intake air amount of the engine has been obtained based on the opening of a throttle valve. A butterfly type throttle valve was used. As described above, the throttle valve opening is used to determine the intake air amount, because the outboard motor is required to be small and lightweight. This is because a large and heavy air flow meter cannot be used.

In order to obtain the intake air amount based on the opening of the throttle valve, a method of estimating it from the opening of the throttle valve and the engine speed at that time has been adopted. An intake air amount map in which the intake air amount of the engine is assigned by the throttle valve opening and the engine speed is stored in the electronic control unit, and the intake air amount data at each time is read from this map. There were things.

On the other hand, the throttle valve used in the engine for the outboard motor is opened so that the air required for the idling operation flows between the valve body and the wall surface of the intake passage during the idling operation. It should be noted that this throttle valve was configured such that, in the fully closed state, the angle formed by the plane orthogonal to the flow direction of intake air and the valve body was about 14 °.

[0005]

However, if the intake air amount is calculated based on the opening of the throttle valve as described above, the intake air amount data is inaccurate when the throttle valve opening is low. There was a problem of becoming. This is because during engine operation, the change in the intake air amount with respect to the change in the throttle valve opening is large at low opening compared to at high opening.

FIG. 9 is a graph showing the relationship between the throttle valve opening and the intake air amount of a throttle valve used in a conventional outboard motor. As shown in FIG. It can be seen that, in the low opening range shown by, the intake air amount greatly increases and decreases even if the throttle valve is slightly opened and closed because the intake negative pressure of the engine is large. Therefore, in the low opening range, it is desirable that the opening area obtained by subtracting the projected area of the throttle valve as viewed from the upstream side from the passage cross-sectional area of the intake passage does not greatly change even when the throttle valve is opened and closed.

FIG. 10 is a graph showing the relationship between the throttle valve opening and the intake passage opening area in the low opening range indicated by the symbol A in FIG. 9, and the rate of change of the opening area is indicated by a solid line in the figure. As shown, the larger the throttle valve opening, the larger it becomes. For example, the amount of change in the opening area per 1 ° of the throttle valve opening is larger in the opening B during low-speed traveling than in the idling opening I. That is, the inclination angle of the solid line extending quadratically is θ1 when the opening is 0,
Θ2 when idling opening I, opening B when traveling at low speed
If θ3 is then, then θ1 <θ2 <θ3. The smaller the inclination angle, the smaller the change amount of the opening area corresponding to the change amount of the throttle valve opening, in other words, the smaller the increase / decrease amount of the intake air amount.

However, the throttle valve that has been conventionally used in the outboard motor does not use the opening region where the inclination angle is smaller than the idling opening I because the air required for idling operation flows. I didn't.

On the other hand, the throttle valve used in the electronically controlled engine for an automobile has a structure in which the intake passage is substantially closed during idling operation in which the throttle valve is fully closed. Then, the air required for the idling operation is configured to flow through the bypass passage that bypasses the valve body of the throttle valve. The bypass passage is formed in the throttle body, and a screw type flow rate adjusting member having a structure for changing the passage cross-sectional area is interposed, and the bypass passage is structured to control the air flow rate during idling operation.

If the throttle valve used in such an electronically controlled engine for an automobile is used in the outboard motor, the throttle valve can be fully closed even during idling operation, and the intake air amount can be changed from 0 when the vehicle is running. Can be weighed. That is, the relationship between the throttle valve opening and the opening area is shown by a chain double-dashed line in FIG. 10, and it is possible to use a region in which the change in the opening area with respect to the change in the throttle valve opening is relatively small during traveling. . With this configuration, when the throttle valve has a low opening, the change in the intake air amount with respect to the change in the opening becomes small, so that the intake air amount can be obtained with high accuracy.

However, if the throttle valve used in the electronic control engine for automobiles is simply diverted to the outboard motor, there is a problem that the structure becomes complicated and the cost becomes high. This is because the engine of the outboard motor often has a throttle valve for each cylinder for performance reasons.

That is, the bypass passage must be provided in the throttle body of the throttle valve for each cylinder, which complicates manufacturing. Furthermore, each throttle valve must be provided with some coupling mechanism to synchronize the bypass passage air flow during idling.

In the prior art, for example, Japanese Patent Laid-Open No. 3-504 is used.
As disclosed in Japanese Patent Publication No. 750, the intake air amount with respect to the opening degree change even when the throttle valve has a low opening degree without adopting a configuration in which the intake passage is closed when the throttle valve is fully closed. There was also a throttle valve device that was designed to reduce the change in. In the throttle valve device disclosed in this publication, the intake passage is divided into a high-speed side and a low-speed side, and a throttle valve is provided in each, and both throttle valves are connected by a link mechanism. And, at low speed, the air intake amount is controlled only by the low speed side throttle valve,
At the time of high rotation, the throttle valve on the low speed side is fully opened, and the air intake amount is controlled by the throttle valve on the high speed side.

However, when a throttle valve device having two throttle valves, one on the high speed side and the other on the low speed side, is installed in a multi-cylinder engine as described above,
An interlocking link mechanism for interlocking a link mechanism that connects two throttle valves per cylinder with a link mechanism of another cylinder is required. That is, since the structure becomes complicated, the outer shape of the intake device becomes large and the cost increases. In addition, there is a fear that the reliability is lowered.

The present invention has been made in order to solve such a problem. In order to reduce the change in the intake air amount with respect to the change in the opening even when the throttle valve has a small opening, The purpose is to prevent the structure from becoming too complicated and too expensive.

[0016]

A throttle valve device for an engine for an outboard motor according to a first aspect of the present invention has an opening area in which a valve body of each throttle valve can secure an intake air amount that is substantially sufficient for idling the engine. Is formed so that the throttle valve is in a fully closed state in the idling state.

In the throttle valve device for an outboard motor engine according to the second aspect of the present invention, when each throttle valve is fully closed, the angle between the plane orthogonal to the flow direction of the intake air and the valve body is approximately 6 degrees. The throttle valve has an idle air passage that connects the upstream side and the downstream side of the throttle valve.

[0018]

According to the first aspect of the invention, the air required for the idling operation is supplied to each cylinder through the hole formed in the valve body of the throttle valve. For this reason, each throttle body does not need to be provided with a passage through which air flows during idling operation.

According to the second aspect of the invention, since the opening of the throttle valve during idling is small, the change in the opening area with respect to the change in the opening of the throttle valve is small. Further, the angle at which the throttle valve is opened from the fully closed state to the fully opened state is larger than that in the conventional case where the valve body has a tilt angle of 14 ° and is in the fully closed state. In other words, the change in the intake air amount when the opening degree changes by 1 ° is smaller than that in the conventional case.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention will be described in detail with reference to FIGS. FIG. 1 is a side view of an outboard engine equipped with a throttle valve device according to the first aspect of the present invention, in which the intake system is cut away. FIG. 2 is a plan view of an outboard engine equipped with a throttle valve device according to the first aspect of the present invention, and the line I--I in FIG. 2 shows the broken position in FIG. FIG. 3 is a front view showing the state of the throttle valve device according to the first invention as seen from the upstream side of the intake flow, and FIG. 4 is the throttle valve opening when an idle air hole is formed in the valve body of the throttle valve. It is a graph which shows the relationship of an opening area. Note that, in FIG. 2, the arrow F indicates the traveling direction.

In these drawings, reference numeral 1 is an outboard engine, and 2 is a cowling that covers the engine 1.
The engine 1 is a 2-cycle V-type 6-cylinder engine and is mounted on a hull connecting portion (not shown) with the crankshaft 3 oriented vertically. A flywheel magneto 4 is mounted on the upper end of the crankshaft 3, and the lower end is connected to a drive shaft extending vertically in the upper case and lower case (not shown) of the outboard motor. A propeller is connected to this drive shaft.

Reference numeral 5 denotes a cylinder body of the engine 1. The cylinder body 5 is located on the left side in the traveling direction of the right cylinder row 5.
a and a left cylinder row 5b located on the right side in the traveling direction. A piston 7 connected to the crankshaft 3 via a connecting rod 6 is connected to the left and right cylinder rows 5a and 5b.
Are placed side by side three by three. Reference numeral 8 is an ignition plug attached to the cylinder head 9.

Reference numeral 10 denotes a crankcase of the engine 1. In the crankcase 10, an air-fuel mixture passage 10a for introducing an air-fuel mixture into a combustion chamber (not shown) is formed for each cylinder. The air-fuel mixture passage 10a opens at the rear surface of the crankcase 10, and the reed valve device 11 attached to the crankcase 10 is attached to the opening. The reed valve device 11 has a conventionally known structure including a reed valve 11a for each air-fuel mixture passage 10a.

A throttle valve device 13 according to the present invention is mounted on the upstream side of the intake flow in the reed valve device 11 via an intake manifold 12. The intake manifold 12 is formed so that the intake passages 12a communicating with the respective mixture passages 10a pass through in the front-rear direction, and are supported and fixed to the crankcase 10 via the reed valve device 11. In addition, the intake passage 12
The upstream opening of a is formed by arranging the intake manifold 12 in two rows in the vertical direction when the intake manifold 12 is viewed from the rear. That is,
The intake passages 12a respectively communicating with the three cylinders of the right cylinder row 5a are opened on the right side of the rear surface of the intake manifold in a vertically aligned state, and the intake passages 12a respectively communicated with the three cylinders of the left cylinder row 5b are formed. The openings are arranged on the left side of the rear surface of the intake manifold in a vertically aligned state. In addition, the openings of the intake passages 12a that are adjacent to each other on the left and right are positioned so as to overlap each other in a side view.

The throttle valve device 13 includes three throttle bodies 1 in which intake passages 14 having a circular cross section are formed, which communicate with the intake passages 12a adjacent to each other on the left and right sides.
5 and a fuel injection device 16 attached to the throttle body 15. Each of the throttle bodies 15 is formed by arranging the above-mentioned intake passages 14, 14 side by side, and the downstream end is bolted to the rear surface of the intake manifold 12 with the throttle valve 17 for each cylinder attached. There is. A common intake silencer indicated by reference numeral 18 in FIG. 1 is connected to the upstream side of these three throttle bodies 15, and the intake passage 14 in the throttle body 15 is communicated with the atmosphere via the intake silencer 18. There is.

As shown in FIG. 3, the throttle valve 17 is a butterfly type valve body 19 which is interposed in the intake passage 14.
And a single valve shaft 20 penetrating left and right through the throttle body 15 and rotatably supported by the throttle body 15 and connecting the valve bodies 19 in the left and right intake passages 14 and supporting the valve body 19. It consists of and. And the valve shaft 2
An end portion of 0 of the throttle body 15 that protrudes to the right when viewed from the traveling direction of the throttle body 15 is connected to a valve shaft 20 of another throttle body 15 via a link mechanism 21. This link mechanism 21 is used for the valve shafts 20 of the three throttle bodies 15.
Are simultaneously rotated in the same direction so that the driver can manually operate them. Further, the link mechanism 21 includes a valve body rotation stopper 21.
The valve body rotation stopper 21a is configured to stop the valve body 19 at a slightly opened position of 1 to 2 ° when fully closed.

A return spring 22 made of a torsion spring is attached to a portion of each valve shaft 20 projecting to the right of the throttle body 15, and the return spring 22 rotates in the direction in which the valve body 19 is closed, that is, counterclockwise in FIG. Rotationally energized. Therefore, the six valve elements 19 are moved to the slightly open position of 1 to 2 ° by the rotational force of the valve shaft 20 by the spring force of the return spring 22 unless the driver performs the opening operation. It will be stopped, and it will be in a substantially closed state. In addition, the peripheral edge of the valve body 19 may be in contact with the inner wall of the intake passage 14 over substantially the entire circumference, instead of being kept in the slightly opened state of 1 to 2 °.

Further, the valve body 19 is provided with one idle air hole 23 at a position above the connecting portion with the valve shaft 20 so as to penetrate the front and back sides thereof. In the fully closed state, six pieces are provided. Both are configured to have the same inclination angle. The idle air hole 23 has a circular opening shape,
The opening area is set so that an intake air amount sufficient to make the engine 1 idle can be secured.

The fuel injection device 16 includes an injector 2 attached to the throttle body 15 for each intake passage 14.
4 and a fuel pipe member 25 for supplying the fuel to the injector 24 and returning the excess fuel from the injector 24 to the suction side of a fuel pump (not shown).

In the throttle valve device 13 configured as described above, the throttle valve 17 is fully closed and the engine 1
Is idling. At this time, almost all of the air sucked from the intake silencer 18 into the intake passage 14 of the throttle body 15 flows into the intake passage 12a of the intake manifold 12 through the idle air holes 23 provided in the valve body 19. Then, while passing through the reed valve device 11 while being mixed with the fuel injected from the fuel injection device 16,
From here, it will be supplied to the combustion chamber of each cylinder via the mixture passage 10a.

When the throttle valve 17 is opened, the link mechanism 21 rotates the valve shafts 20 of the three throttle bodies 15 clockwise in FIG. 1 to open the valve body 19. When the valve body 19 is opened, the opening area of the intake passage 14 increases according to the opening degree. The manner in which the opening area changes is shown by a chain double-dashed line in FIGS. 4 and 10. As shown in these figures, the opening area of the intake passage 14 is
When the opening 9 is in the fully closed state and the opening is 0 to 2 °, S corresponding to the opening area of the idle air hole 23 becomes S, and the valve body 19
As S.sub.2 opens, the S increases with the same change rate as the conventional open area change curve shown by the solid line in FIG.

That is, when the cruise is started, the inclination angle of the opening area change curve (two-dot chain line) is θ1. Therefore, during low-speed traveling with a small throttle valve opening, it is possible to use an opening area in which the change in the opening area with respect to the change in the throttle valve opening is relatively small. In other words, conventionally, the vehicle could not travel at a lower opening than the idling opening indicated by I in FIG. 10, but in the device of the present embodiment, the idling opening is substantially when the throttle valve opening is 0 °. become. As a result, when the throttle valve 17 has a low opening, the change in the intake air amount with respect to the change in the opening becomes small, so that the intake air amount can be obtained with high accuracy.

Therefore, according to this embodiment, the air required for the idling operation is supplied to each cylinder through the idle air hole 23 formed in the valve body 19 of the throttle valve 17. Therefore, each throttle body 15 does not need to have a passage through which air flows during idling operation.

Next, an embodiment of the second invention will be described with reference to FIGS. FIG. 5 is an enlarged cross-sectional view showing a main part of a throttle valve device according to a second aspect of the invention, and FIG. 6 is a front view showing the state of the throttle valve device according to the second aspect of the invention as seen from the upstream side of the intake flow. FIG. 7 is a graph showing the relationship between the throttle valve opening and the opening area in the throttle valve device according to the second invention. FIG. 7A shows the change in the opening area until it reaches the maximum. Figure (b) shows a throttle valve opening of 20 °
It shows the change of the opening area until. In these figures, the same or equivalent members as those described in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

The throttle valve 17 shown in FIG. 5 is constructed so that when fully closed, the angle α between the valve element 19 and the plane orthogonal to the direction of intake air flow is 6 °. ing. The valve body 19 is not provided with the idle air holes shown in the embodiments of FIGS. Therefore, when the engine is idling, the throttle valve 17 is slightly opened to allow the necessary air to flow.

The thickness of the valve body 19 is set to about 1.5 mm to 2 mm from the viewpoint of manufacturing and performance. That is, if the thickness is made thicker or thinner than this range, it becomes difficult to punch and form the valve body 19 with a press. Furthermore, if the valve body 19 is formed thinner than the above thickness range, the rigidity of the valve body 19 is reduced, and the valve body 19 is apt to bend due to the negative pressure of the intake air when the opening is small. It is easy to get stuck. On the contrary, if it is formed thick, the opening area at the time of full opening becomes small and the inclination angle α at the time of fully closing becomes large.

That is, the inclination angle α is set to 6 ° when the thickness of the valve body 19 is set to the above-mentioned dimension.
This is because when the inclination angle is 6 °, the intake passage 14 can be smoothly opened and closed without being bitten. In order to increase the area of the contact portion between the peripheral edge of the valve body 19 and the inner wall of the intake passage 14 at an inclination angle of 6 °, the peripheral surface of the valve body 19 is slightly moved along the inner wall in this embodiment. It is tilted.

The throttle valve device 13 is constructed by using the throttle valve 17, and the valve body rotation stopper 2 provided in the link mechanism 21 is used to hold the throttle valve device 13 in the slightly opened state during the idling operation as described above.
1a is used. That is, this valve body rotation stopper 21a
By restricting the amount of rotation of the valve shaft 20 by this, the valve body 19 can be held at the idling opening degree in the state where the opening operation is not performed.

In the throttle valve 17 constructed as described above, the opening area is shown in FIGS. 7 (a) and 7 (b) with respect to changes in the opening.
It changes as shown in. In the figure, the alternate long and two short dashes line indicates the throttle valve of the present embodiment, and the solid line indicates the throttle valve in which the valve body in the fully closed state used in the conventional outboard motor has an inclination angle of 14 °. As shown in the figure, it can be seen that the slope of the curve extending like a quadratic function is smaller in this embodiment than in the conventional case. This is because the angle when the throttle valve 17 is opened from the fully closed state to the fully opened state is larger than that in the conventional case where the valve body has a tilt angle of 14 ° and is in the fully closed state. That is, the change in the opening area when the throttle valve opening changes by 1 ° is smaller in this embodiment.

Therefore, even if the air required for the idling operation is supplied to the cylinder by opening the throttle valve 17 to the idling opening, the throttle valve 1
When the opening amount of 7 is low, the change of the intake air amount due to the change of the opening amount becomes small, and the intake air amount can be obtained with high accuracy.

Although the valve body 19 is not provided with an idle air hole in the above embodiment, the valve body 19 of the throttle valve 17 shown in FIGS. 5 to 7 is shown in FIGS. 1 to 4. Idle air holes 23 can also be drilled. In the case of such a configuration, the valve body rotation stopper 2 of the link mechanism 21
The opening degree of the valve body 19 is set to be fully closed or 1 to 2 ° by the idling operation 1a.

As described above, when the valve body 19 provided with the idle air hole 23 is configured so that the inclination angle is 6 ° in the fully closed state, the relationship between the throttle valve opening and the opening area of the intake passage is shown in FIG. 8 (a) and 8 (b). FIG. 8 is a graph showing a relationship between a throttle valve opening and an opening area in a throttle valve device configured such that a tilt angle of a valve body provided with an idle air hole is 6 ° in a fully closed state. FIG. 7A shows the change in the opening area until it becomes maximum, and FIG. 7B shows the change in the opening area until the throttle valve opening becomes 30 °. Also in this figure, the chain double-dashed line indicates the throttle valve of this embodiment, and the solid line indicates that the tilt angle of the valve body in the fully closed state, which is conventionally used in outboard motors, is 14 degrees.
Indicates a throttle valve that is °.

With this configuration, as shown in FIG.
As is apparent from (b), the inclination angle of the two-dot chain line extending in a quadratic function is smaller than the solid line, and moreover, the inclination angle of the valve body 19 during the idling operation by the opening area S of the idle air hole 23. Can be made smaller. Therefore, as compared with the case where the idle air hole 23 is not provided, it is possible to use the opening area in which the change in the opening area with respect to the change in the throttle valve opening is small during traveling. In other words,
In FIG. 7, for example, if the idling opening is 10 °, it was not possible to travel at a lower opening, but in the device of this embodiment, the idling opening is substantially effective when the throttle valve opening is 0 °. It becomes degree. As a result, when the throttle valve 17 has a low opening, the change in the intake air amount with respect to the change in the opening becomes small, so that the intake air amount can be obtained with high accuracy.

That is, in order to increase the opening area by ΔS from the idling opening in FIG. 8 (b), the throttle valve 17 is conventionally opened by the opening indicated by a in the figure. Then, the opening b which is about twice the opening a
Since it is necessary to open the throttle valve 17 only, the change in the opening area with respect to the change in the opening degree of the throttle valve 17 is about 1/2 in this embodiment.

In this embodiment, the valve body 1 in the fully closed state
Although the opening degree of 9 is set to 6 °, the same effect can be obtained in the opening range of 5 to 7 °.

[0046]

As described above, in the throttle valve device for an engine for an outboard motor according to the first aspect of the invention, the valve body of each throttle valve has an opening capable of ensuring an intake air amount that is substantially sufficient for idling the engine. Since a hole with an area is drilled and this throttle valve is configured to be in a fully closed state in the idling state, the air required for idling operation is supplied to each cylinder through the hole drilled in the valve body of the throttle valve. Supplied.

Therefore, it is not necessary to provide each throttle body with a passage through which air flows during idling operation. Therefore, even when the throttle valve has a low opening, the structure can be simplified and the manufacturing cost can be kept low in order to reduce the change in the intake air amount with respect to the opening change.

In the throttle valve device for an outboard engine according to the second aspect of the present invention, when each throttle valve is fully closed, the angle between the plane orthogonal to the flow direction of the intake air and the valve body is about 6. Since the idle air passage that connects the upstream side and the downstream side of the throttle valve is provided, most of the air required for idling operation is supplied through this idle air passage. It

Therefore, the throttle valve in the idling state can be kept in a substantially fully closed state, and the throttle opening from the idling state to the fully open state is increased, and the intake air amount when the opening changes by 1 °. It is possible to reduce the change in the opening area of the intake passage even when the throttle valve is opened and closed in the idling region. That is, the angle when the throttle valve is opened from the fully closed state to the fully opened state is larger than that in the conventional case where the valve body has a tilt angle of 14 ° and is in the fully closed state.
For example, the change in the intake air amount when the opening degree changes by 1 ° is smaller than in the conventional case.

Therefore, while adopting a construction in which the air required for idling operation is supplied to the cylinder by opening the throttle valve to the idling opening degree, the intake air with respect to the opening degree change even when the throttle valve is at a low opening degree. In order to reduce the change in the amount, it is not necessary to adopt a configuration in which a throttle valve is provided in each of the high speed side intake passage and the low speed side intake passage and both throttle valves are connected by a link mechanism, so the structure is simple. In addition, the manufacturing cost can be kept low.

A throttle valve device according to a third aspect of the present invention is the throttle valve device according to the second aspect of the invention, in which an idle air passage is formed in the throttle valve, and an intake air amount that is substantially sufficient for idling operation of the engine is secured. Since it is formed of holes having an opening area that can be realized, it can be realized at a very low cost with a simple structure.

Further, in the throttle valve device according to the first to third inventions, since it can be implemented mainly by changing the structure of the valve body as compared with the conventional one, there is almost no additional mechanism and the reliability is high. There is also an effect.

[Brief description of drawings]

FIG. 1 is a side view of an outboard engine equipped with a throttle valve device according to a first aspect of the present invention, in which the intake system is cut away.

FIG. 2 is a plan view of an outboard engine equipped with a throttle valve device according to a first aspect of the present invention.

FIG. 3 is a front view showing a state in which the throttle valve device according to the first invention is viewed from the upstream side of the intake flow.

FIG. 4 is a graph showing a relationship between a throttle valve opening and an opening area when an idle air hole is formed in a valve body of the throttle valve.

FIG. 5 is an enlarged sectional view showing a main part of a throttle valve device according to a second invention.

FIG. 6 is a front view showing a state of the throttle valve device according to the second invention as seen from the upstream side of the intake flow.

FIG. 7 is a graph showing a relationship between a throttle valve opening and an opening area in the throttle valve device according to the second invention.

FIG. 8 is a graph showing a relationship between a throttle valve opening and an opening area in a throttle valve device configured such that a valve body provided with an idle air hole has a tilt angle of 6 ° in a fully closed state. .

FIG. 9 is a graph showing a relationship between a throttle valve opening of a throttle valve used in a conventional outboard motor and an intake air amount.

FIG. 10 is a graph showing the relationship between the throttle valve opening and the intake passage opening area.

[Explanation of Codes] 1 ... Engine, 12 ... Intake manifold, 13 ... Throttle valve device, 14 ... Intake passage, 15 ... Throttle body, 16 ... Fuel injection device, 17 ... Throttle valve, 19 ...
Valve body, 20 ... Valve shaft, 23 ... Idle air hole.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 9/02 J // B63H 20/00

Claims (3)

[Claims] 1. A throttle valve device for an engine for an outboard motor, wherein a plurality of throttle valves are provided in a valve body of each throttle valve, the intake air amount of a multi-cylinder engine being obtained based on the opening of a butterfly type throttle valve. An outboard engine characterized in that a hole having an opening area capable of securing an intake air amount that is substantially sufficient for idling the engine is provided, and the throttle valve is configured to be substantially fully closed in an idling state. Throttle valve device. 2. A throttle valve device for an outboard engine, wherein a plurality of throttle valves are provided, and each throttle valve is in a fully closed state, in which an intake air amount of a multi-cylinder engine is determined based on the opening of a butterfly type throttle valve. The angle formed by the valve body and the plane orthogonal to the flow direction of intake air is approximately 6 °
A throttle valve device for an outboard engine, which is configured to be (5 to 7 °), and is provided with an idle air passage that connects the upstream side and the downstream side of the throttle valve. 3. The throttle valve device for an outboard engine according to claim 2, wherein the idle air passage has an opening area formed in the throttle valve and capable of securing an intake air amount that is substantially sufficient for idling the engine. A throttle valve device for an engine for an outboard motor, which is configured by a hole.