JP2024064142A - Throttle device and intake system - Google Patents

Abstract

[Problem] To provide a throttle device and an intake system capable of generating a swirling flow in a combustion chamber by reducing the number of parts, simplifying the structure, reducing costs, reducing passage resistance, etc. [Solution] A throttle body 10 defines a main passage 12 that forms part of a main intake passage and a secondary passage 17 that branches off from the main passage and forms part of a secondary intake passage, and a butterfly valve 30 that rotates about a predetermined axis S to open and close the main passage, the butterfly valve having a first half 31a that moves upstream when the valve is open and a second half 31b that moves downstream to open and close the main passage, and including an opening/closing plate 31 that opens and closes the main passage and a protrusion 32 that protrudes downstream from the first half when the valve is closed, and a branch port 17a of the secondary passage is located downstream of the opening/closing plate in a closed state, and is formed at a position facing the second half when the butterfly valve opens, where the opening area that communicates with the main passage upstream of the opening/closing plate increases according to the opening degree of the butterfly valve until the butterfly valve reaches a predetermined opening degree. [Selected figure] Figure 5

Description

The present invention relates to a throttle device and intake system for an internal combustion engine mounted on a vehicle, such as a motorcycle.

A conventional intake system for an internal combustion engine includes an intake passage that guides air (intake) introduced from the outside into the combustion chamber of the internal combustion engine, an intake valve that opens and closes an intake port that is part of the intake passage, an injector that is located near the intake port and injects fuel, a first throttle valve that is located midway through the intake passage and opens and closes the intake passage, a second throttle valve that is located downstream of the first throttle valve and opens and closes the intake passage, and a sub-passage that branches off from the intake passage between the first throttle valve and the second throttle valve and joins the downstream side of the injector (see, for example, Patent Document 1).

In this intake system, during partial load, the downstream second throttle valve is closed and only the upstream first throttle valve is opened, allowing air introduced from the outside to flow through the secondary passage and into the passage downstream of the injector, where it is mixed with the injected fuel, promoting fuel atomization.

However, in the above intake system, two throttle valves (first throttle valve, second throttle valve) are rotatably mounted on a body that defines the intake passage, and each is designed to open and close. This requires two throttle valves, as well as a mechanism for driving the opening and closing of each throttle valve, resulting in an increase in the number of parts, higher costs, and a more complex structure. In addition, when fully open, the placement of two throttle valves in the passage increases passage resistance compared to the case of a single throttle valve.

Another known intake system is an intake device that includes an inlet pipe that defines an intake passage that guides intake air introduced from the outside into the combustion chamber of the internal combustion engine, an intake valve that opens and closes the intake passage at a position facing the combustion chamber, an injector provided in the inlet pipe to inject fuel midway through the intake passage, a throttle valve provided in the inlet pipe to open and close the intake passage, a partition plate that divides the intake passage into an upper intake passage and a lower intake passage downstream of the throttle valve, and an intake distribution valve provided in the inlet pipe downstream of the throttle valve and adjacent to the upstream edge of the partition plate, and that changes the ratio of air flowing through the upstream intake passage and the downstream intake passage by appropriately rotating the intake distribution valve (see, for example, Patent Document 2).

However, the above intake system requires an intake distribution valve, and a mechanism for driving both the throttle valve and the intake distribution valve is required, resulting in high costs and a complex structure. Furthermore, when the throttle valve is fully open, the intake distribution valve and the shaft supporting the intake distribution valve get in the way of the intake flow, increasing passage resistance.

JP 2002-327665 A Japanese Patent No. 5925878

The present invention was made in consideration of the above circumstances, and its purpose is to provide a throttle device and intake system that can reduce the number of parts, simplify the structure, reduce costs, reduce passage resistance, etc., increase the flow rate of intake air flowing through the auxiliary intake passage, and generate swirling flows such as swirl flows and tumble flows in the combustion chamber.

The throttle device of the present invention is a throttle device applied to the intake system of an internal combustion engine, which includes a main intake passage that guides intake air into a combustion chamber and is opened and closed by an intake valve at a position facing the combustion chamber, and an auxiliary intake passage that branches off from the middle of the main intake passage and joins the main intake passage upstream of the intake valve. The throttle device is equipped with a throttle body that defines a main passage that is a part of the main intake passage and an auxiliary passage that branches off from the main passage and is a part of the auxiliary intake passage, and a butterfly valve that rotates around a predetermined axis to open and close the main passage, The fly valve includes an opening and closing plate having a first half portion that moves upstream when the valve is opened and a second half portion that moves downstream to open and close the main passage, and a protrusion that protrudes downstream from the first half portion when the valve is closed. The branch port of the sub-passage is located downstream of the opening and closing plate in the closed state, and is formed in a position facing the second half portion when the butterfly valve opens, where the opening area communicating with the main passage upstream of the opening and closing plate increases according to the opening of the butterfly valve until the butterfly valve reaches a predetermined opening degree.

In the above throttle device, the protrusion may be a flat back plate fixed to the opening/closing plate with a predetermined gap therebetween.

In the above throttle device, the butterfly valve may be configured so that intake air can pass between the opening and closing plate and the back plate when in a fully open state.

In the above throttle device, the rear plate may be configured to have an outer contour that corresponds to the first half of the opening and closing plate.

In the throttle device, the branch port of the sub-passage may be located downstream of the axis in the main passage.

In the above throttle device, the main passage may have a circular cross section, the sub-passage may have a circular cross section, and the branching port of the sub-passage may have a circular or elliptical shape.

In the above throttle device, the branch port of the sub-passage may be arranged so that its center is located on a plane including the center line of the main passage and the center line of the opening and closing plate perpendicular to the axis.

In the above throttle device, the secondary passage may be configured to extend downstream from the branch port for a predetermined length at a predetermined inclination angle with respect to the center line of the primary passage.

In the above throttle device, the throttle body may have a connector portion that connects the passage members that define the auxiliary intake passage.

In the above throttle device, the throttle body may include a bypass passage that bypasses the butterfly valve, and the branching port of the sub-passage may be located away from the merging port of the bypass passage.

In the above throttle device, the throttle body may include a detection port that detects the pressure in the main passage downstream of the butterfly valve, and the branch port of the sub-passage may be located away from the detection port.

The intake system of the present invention includes a main intake passage that guides intake air into the combustion chamber and is opened and closed by an intake valve at a position facing the combustion chamber, a butterfly valve that rotates around a predetermined axis to open and close the main intake passage, an auxiliary intake passage that branches off from the middle of the main intake passage and merges with the main intake passage upstream of the intake valve, and a fuel injection valve that injects fuel into the middle of the main intake passage or into the combustion chamber. The butterfly valve includes an opening and closing plate that has a first half that moves upstream when the valve is open and a second half that moves downstream to open and close the main passage, and a protrusion that protrudes downstream from the first half when the valve is closed. The branch port of the auxiliary intake passage is located downstream of the opening and closing plate in the closed state, and is formed in a position facing the second half when the butterfly valve opens, where the opening area that communicates with the main intake passage upstream of the opening and closing plate increases according to the opening of the butterfly valve until the butterfly valve reaches a predetermined opening.

In the above-mentioned intake system, the protrusion may be a flat back plate fixed to the opening and closing plate with a predetermined gap therebetween.

In the above intake system, the butterfly valve may be configured so that intake air can pass between the opening and closing plate and the back plate when in a fully open state.

In the above-mentioned intake system, the rear panel may be configured to have an outer contour that corresponds to the first half of the opening and closing panel.

In the above intake system, the branch port of the auxiliary intake passage may be located downstream of the axis in the main intake passage.

In the above-mentioned intake system, the main intake passage may have a circular cross section, the auxiliary intake passage may have a circular cross section, and the branching port of the auxiliary intake passage may have a circular or elliptical shape.

In the above-mentioned intake system, the branch port of the auxiliary intake passage may be arranged so that its center is located on a plane including the center line of the main intake passage and the center line of the opening and closing plate perpendicular to the axis.

In the above intake system, the auxiliary intake passage may be configured to extend downstream from the branch port for a predetermined length at a predetermined inclination angle with respect to the center line of the main intake passage.

In the above intake system, the confluence of the auxiliary intake passage may be configured to be oriented upstream of the intake valve in a direction that generates a swirl flow in the combustion chamber.

In the above-mentioned intake system, the confluence of the auxiliary intake passage may be configured to be oriented upstream of the intake valve in a direction that creates a tumble flow in the combustion chamber.

The throttle device and intake system configured as above can reduce the number of parts, simplify the structure, lower costs, and reduce passage resistance, while increasing the flow rate of intake air flowing through the auxiliary intake passage, and can generate swirling flows such as swirl flows and tumble flows in the combustion chamber, thereby contributing to improved combustion efficiency.

1 is a cross-sectional view that shows a schematic diagram of an intake system of an internal combustion engine equipped with a throttle device according to an embodiment of the present invention. 1 is a partial perspective view of an intake system including a throttle device according to an embodiment of the present invention; 1 is a perspective view of a throttle device according to one embodiment, viewed obliquely from the upstream side. FIG. 1 is a perspective view of a throttle device according to one embodiment, viewed obliquely from the downstream side. FIG. 1 is a cross-sectional view of a throttle device according to one embodiment, taken along a plane including a center line of a butterfly valve perpendicular to a center line of a main passage that forms a part of a main intake passage and an axis of a rotary shaft. FIG. 1 is a perspective cross-sectional view of a throttle device according to one embodiment, taken along a plane including a center line of a butterfly valve perpendicular to a center line of a main passage that forms a part of a main intake passage and an axis of a rotary shaft. FIG. 1 is a perspective cross-sectional view of a throttle device according to one embodiment, taken along a plane including a center line of a main passage that forms a part of a main intake passage and an axis line of a rotation shaft. 1 is a perspective cross-sectional view of a rotary shaft and a butterfly valve included in a throttle device according to one embodiment, cut along a plane perpendicular to the axis. 1 is a perspective view of a butterfly valve included in a throttle device according to one embodiment of the present invention; 3 is a cross-sectional view showing a schematic diagram of the positional relationship between a main passage, a sub-passage and a butterfly valve, and the operation of the butterfly valve in the throttle device according to one embodiment. FIG. 4 is a cross-sectional view showing a schematic flow of intake air when a butterfly valve is in a predetermined open angular position in a throttle device according to one embodiment. FIG. 4 is a cross-sectional view illustrating a flow of intake air when a butterfly valve is in a fully open position in the throttle device according to one embodiment. FIG. 4 is a cross-sectional view showing the relationship between an inner diameter of a main passage, an inner diameter of an auxiliary passage, the position of the auxiliary passage from the axis of a rotary shaft, and an inclination angle of the auxiliary passage in a throttle device according to one embodiment. FIG. This shows the results of a simulation of the intake flow in the main intake passage (main passage) and the auxiliary intake passage (auxiliary passage) when the butterfly valve is opened slightly (by about 10 degrees) from the fully closed position in a throttle device according to one embodiment, and is an intake flow diagram in a cross section cut by a plane perpendicular to the axis of the rotating shaft and including the centerlines of the main intake passage (main passage) and the auxiliary intake passage (auxiliary passage). FIG. 11 is an intake flow diagram viewed from a direction perpendicular to the top surface of the piston, showing the results of a simulation of the flow of intake air flowing from the main intake passage and the auxiliary intake passage into the combustion chamber in a throttle device according to one embodiment. 5 is a graph showing the relationship between the opening degree of a butterfly valve and the overall passage flow rate and the auxiliary intake passage flow rate in the main intake passage and the auxiliary intake passage in an intake system including a throttle device of the present invention. FIG. 11 is a cross-sectional view of a throttle device according to another embodiment of the present invention, taken along a plane including a center line of a butterfly valve perpendicular to a center line of a main passage that forms a part of a main intake passage and an axis of a rotary shaft. FIG. 4 is a cross-sectional view showing a schematic diagram of an intake system for an internal combustion engine according to another embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
The throttle device of the present invention is, for example, installed in the intake system of an internal combustion engine mounted on a motorcycle, midway through the intake pipe downstream of an air cleaner.

A throttle device M according to one embodiment is applied to an intake system that guides intake air to a combustion chamber C of an internal combustion engine E, as shown in FIG.
The internal combustion engine E includes a cylinder block 1, a piston 2, a cylinder head 3, an intake valve 4a, an exhaust valve 4b, an exhaust pipe 5, an intake system IS, and the like.
The cylinder head 3 cooperates with the upper surface of the piston 2 to define a combustion chamber C, and has an intake port 3a which forms part of the main intake passage, a secondary port 3b which forms part of the secondary intake passage, and an exhaust port 3c. It also houses a drive mechanism (not shown) which opens and closes the intake valve 4a and the exhaust valve 4b, an ignition plug (not shown), etc.

The auxiliary port 3b is formed to merge with the intake port 3a immediately upstream of the intake valve 4a. That is, the auxiliary intake passage (auxiliary port 3b) has a merging port _3b1 that merges with the main intake passage (intake port 3a) upstream of the intake valve 4a.
The joining port _3b1 of the auxiliary port 3b is oriented in a direction that generates a swirl flow (horizontal vortex) in the combustion chamber C. Specifically, as shown in Figure 15, the joining port _3b1 of the auxiliary port 3b is formed so that it joins the intake port 3a from an oblique direction and the intake air flows in a tangential direction to the inner wall surface of the combustion chamber C.

The intake system IS includes an intake port 3a and an auxiliary port 3b in the cylinder head 3, an air cleaner 6 that draws in outside air, an intake pipe 7 as a passage member, an auxiliary intake pipe 8 as a passage member, a fuel injection valve 9 arranged midway through the intake pipe 7, and a throttle device M arranged midway through the intake pipe 7 upstream of the fuel injection valve 9.

The intake pipe 7 is formed from a metal or resin material, etc., and defines a main intake passage 7a having a circular cross-section through which the intake air sucked in by the air cleaner 6 passes, and is positioned so as to be interposed between the air cleaner 6 and the intake port 3a of the cylinder head 3.
The auxiliary intake pipe 8 is formed from a metal, resin, or rubber material, etc., and defines an auxiliary intake passage 8a with a circular cross-section for allowing intake air to pass through, and is positioned so as to be interposed between the throttle device M and the auxiliary port 3b of the cylinder head 3.
The fuel injection valve 9 is disposed in the intake pipe 7 and injects fuel into the main intake passage 7a near the intake port 3a.

As shown in Figures 2 to 7, the throttle device M includes a throttle body 10, a rotating shaft 20 centered on an axis S, a butterfly valve 30, a drive unit 40 that drives the butterfly valve 30 to open and close, an adjustment valve 50, and a sensor unit U. Here, the sensor unit U includes an angle position sensor 60, a pressure sensor 70, and a temperature sensor 80.

The throttle body 10 is made of a metal material such as aluminum or a resin material, and includes an upstream connection portion 11a, a downstream connection portion 11b, a main passage 12, a shaft hole 13 through which the rotating shaft 20 passes, a bypass passage 14, a housing portion 15 that houses the adjustment valve 50, a detection port 16, a sub-passage 17, and a connector portion 18.

The upstream connection portion 11 a is connected to the upstream intake pipe 7 which is connected to the air cleaner 6 .
The downstream connection portion 11b is connected to a downstream intake pipe 7 that is connected to an intake port 3a of a cylinder head 3 of the internal combustion engine E.

The main passage 12 functions as a part of the main intake passage that guides the intake air to the combustion chamber C, and is formed in a cylindrical shape that has a circular cross section centered on a center line L perpendicular to the axis S and extends in the direction of the center line L. As shown in Fig. 5, the main passage 12 is formed in a conical shape whose passage area increases from a predetermined region where the butterfly valve 30 is rotatably disposed toward the upstream connecting portion 11a and the downstream connecting portion 11b.
As shown in Figure 7, the shaft hole 13 is formed as a circular hole so that the rotating shaft 20 can be passed through freely rotatably around the axis S, and an annular recess 13a is formed on the outside in the direction of the axis S into which a lip-type seal Rs is fitted.

As shown in FIGS. 5 to 7 , the bypass passage 14 is made up of an upstream passage 14 a branching off from the main passage 12 upstream of the butterfly valve 30, a downstream passage 14 b joining the main passage 12 downstream of the butterfly valve 30, and a communicating passage (not shown) interposed between the upstream passage 14 a and the downstream passage 14 b and whose passage area is adjusted by an adjustment valve 50.
That is, the bypass passage 14 branches off from the main passage 12 at a branch port _14a1 located upstream of the butterfly valve 30 to introduce the intake air, and then bypasses the butterfly valve 30 and discharges the intake air to the main passage 12 at a junction port _14b1 located downstream of the butterfly valve 30.

As shown in FIGS. 5 and 6, the accommodation portion 15 is an area that accommodates a valve body 51 of the adjustment valve 50 so that the valve body 51 can freely reciprocate, and also functions as a communication passage that communicates between the upstream passage 14a and the downstream passage 14b.
As shown in FIG. 7 , the detection port 16 opens into the main passage 12 downstream of the butterfly valve 30 and is formed so that a pressure sensor 70 provided in the sensor unit U is exposed to the intake air in the main passage 12.

The sub-passage 17 is a part of the sub-intake passage, and as shown in Figures 5 and 6, it branches off from the main passage 12 downstream of the butterfly valve 30 and extends downstream at a predetermined inclination angle with respect to the center line L of the main passage 12 for a predetermined length from the branch port 17a, which is the starting point of the sub-passage 17. Specifically, the sub-passage 17 is formed as a cylindrical hole that has a circular cross section centered on the center line L2 that forms an angle β with the center line L of the main passage 12 and extends in the direction of the center line L2. Therefore, the branch port 17a of the sub-passage 17 is an ellipse that is elongated in the direction of the center line L of the main passage 12.

As shown in FIG. 10 , the branch port 17 a of the sub-passage 17 is disposed in the main passage 12 so as to be located a distance ΔL downstream of the axis S of the rotating shaft 20, and so as to have its center (center line L2) located on a plane (the cross section shown in FIGS. 5 and 10 ) including the center line L of the main passage 12 and the center line L3 of the butterfly valve 30 perpendicular to the axis S of the rotating shaft 20.
In this way, since the branch port 17a is disposed in the center of the main passage 12 and the butterfly valve 30 in the direction of the axis S, the intake air can be efficiently guided toward the sub-passage 17.
As shown in FIG. 7, the branch port 17a of the sub passage 17 is disposed at a position away from the junction port _14b1 of the bypass passage 14 and away from the detection port 16.
In this way, since the branch port 17a is disposed at a position away from the merging port _14b1 and the detection port 16, mutual influence can be prevented and each can perform its respective functions.

Furthermore, as shown in FIG. 10, the branch port 17a of the sub-passage 17 is located downstream of the butterfly valve 30 in the closed state, and is formed at a position where the opening area A communicating with the main passage 12 upstream of the butterfly valve 30 increases according to the opening degree of the butterfly valve 30 until the butterfly valve 30 reaches a predetermined opening degree θ.

Specifically, when the butterfly valve 30 rotates clockwise from the fully closed position in FIG. 10, the opening area A of the branch port 17a that communicates with the main passage 12 upstream of the second half 31b of the opening/closing plate 31 of the butterfly valve 30 gradually increases as the butterfly valve 30 rotates, as shown in FIG. 10 and FIG. 11, until the opening area A of the branch port 17a becomes maximum when the butterfly valve 30 rotates to the predetermined opening angle θ.

In this rotation region, as shown in FIG. 11, the intake air flowing in from the main passage 12 upstream of the butterfly valve 30 is guided along the opening/closing plate 31 of the butterfly valve 30, particularly to the second half portion 31b which is inclined toward the downstream side, and is actively directed toward the branch port 17a and flows into the sub-passage 17.
On the other hand, the intake air flowing from the main passage 12 upstream of the butterfly valve 30 and flowing around the first half portion 31a flows behind the back plate 32 and is disturbed, weakening the flow of intake air through the main passage 12. Therefore, the flow rate of the intake air flowing into the secondary passage 17 increases relatively compared to when the back plate 32 is not present.

In the region where the butterfly valve 30 rotates from the predetermined opening angle θ to the fully open position, there is no change in the opening area of the branch port 17, and the butterfly valve 30 becomes parallel to the center line L of the main passage 12 (horizontal in FIG. 12). Therefore, the intake air flowing through the main passage 12 is no longer directed toward the sub-passage 17 by the butterfly valve 30 (opening/closing plate 31), as shown in FIG. 12, and flows downstream within the main passage 12.
In particular, the butterfly valve 30 has a gap between the opening/closing plate 31 and the back plate 32, allowing the intake air to flow between them. Therefore, even with the back plate 32, the intake air flows smoothly.

In this way, the branch port 17a of the secondary passage 17 is arranged to face the second half 31b, which moves downstream (inclines toward the downstream side) when the butterfly valve 30 opens, and the guiding action of the butterfly valve 30 actively guides the intake air in the main passage 12 to flow into the secondary passage 17 until it reaches the predetermined opening angle θ. In particular, the back plate 32, which acts as a protrusion protruding from the rear of the first half 31a, disrupts the flow of intake air in the main passage 121 that has flowed downstream of the first half 31a, weakening the intake air flow in the main passage 12, thereby relatively increasing the flow rate of intake air flowing into the secondary passage 17.

The connector portion 18 is formed of a metallic cylindrical pipe, and is press-fitted into the throttle body 10 so as to communicate with the auxiliary passage 17. The connector portion 18 is connected to the upstream end of the auxiliary intake pipe 8, which serves as a passage member.
Here, an example has been shown in which the connector portion 18 is formed as a separate member, but it may be formed integrally with the throttle body 10 .

The rotating shaft 20 is made of a metal material or the like and is formed to have a circular cross section extending in the direction of the axis S, and as shown in Figure 7, is provided with a slit 21 and two screw holes 22 in the central region for fitting the butterfly valve 30, a connecting portion 23 at one end for connecting the drive unit 40, and a bottomed cylindrical portion 24 at the other end. In addition, a two-face width portion 21a is formed on the outer periphery of the slit 21 region in order to reduce passage resistance in the main passage 12.
The connecting portion 23 has a two-face width portion into which the drum 41 of the drive unit 40 is fitted so as to rotate integrally therewith.
The bottomed cylindrical portion 24 is provided with a permanent magnet 24a on its inner circumferential surface, and is formed to accommodate the cylindrical angular position sensor 60 of the sensor unit U therein in a non-contact manner.

The rotating shaft 20 is inserted through the shaft hole 13 of the throttle body 10, and the butterfly valve 30 is fitted into the slit 21 and fastened with a screw b2, thereby holding the butterfly valve 30 openable and closable. The outer circumferential surface of the rotating shaft 20 is sealed by a lip seal Rs on the outside of the shaft hole 13 in the direction of the axis S.

As shown in FIGS. 5 to 9, the butterfly valve 30 includes an opening/closing plate 31, a back plate 32 as a protruding portion, and two connecting portions 33.
The opening/closing plate 31 opens and closes the main passage 12, is formed in an approximately circular plate shape, and has a first half portion 31a that moves upstream when the valve is opened, a second half portion 31b that moves downstream when the valve is opened, and two circular holes 31c through which the screws b2 pass.
The rear plate 32 is disposed with a predetermined gap between it and the opening/closing plate 31, and is fixed to the opening/closing plate 31 by two connecting portions 33. The rear plate 32 has an outer contour corresponding to the first half portion 31a of the opening/closing plate 31, i.e., is formed in a semicircular shape.
The two connecting portions 33 are formed between the opening/closing plate 31 and the rear plate 32 so that intake air can pass through when fully open, and so that the projected area in the flow direction is as small as possible so as not to increase passage resistance.
Here, the butterfly valve 30 may have the opening/closing plate 21, the back plate 32, and the connecting portion 33 integrally formed from a resin material or the like, or may be formed from a metal material or the like and fastened to each other with screws or the like.

The butterfly valve 30 having the above-mentioned configuration is arranged so that after the rotating shaft 20 is passed through the shaft hole 13, the opening/closing plate 31 is passed through the slit 21 and the back plate 32 is fixed to the rotating shaft 20 by the screw b2 so that in the closed valve state, the back plate 32 is positioned downstream of the first half body portion 31a (i.e., protrudes downstream from the first half body portion 31a), thereby opening and closing the main passage 12.
When the butterfly valve 30 is driven by the drive unit 40 to open, i.e., when it moves from the fully closed position to the fully open position, as shown in Figure 10, the first half portion 31a changes its posture so that it becomes horizontal while inclining toward the upstream side of the main passage 12, and the second half portion 31b changes its posture so that it becomes horizontal while inclining toward the downstream side of the main passage 12.

As shown in Figures 3, 4 and 7, the drive unit 40 drives the rotating shaft 20 to rotate around the axis S, and includes a drum 41 that is connected and fixed to the connecting portion 23 of the rotating shaft 20, and a coil spring 42 that is arranged around the rotating shaft 20 between the drum 41 and the throttle body 10.
The drum 41 has a locking hole 41a to which a wire connected to the throttle grip is locked, a locking portion 41b to which a coil spring 42 is locked, and a contact lever 41c.
As shown in FIG. 3, one end 42a of the coil spring 42 is engaged with a locking portion 41b of the drum 41, and the other end is engaged with a locking portion (not shown) of the throttle body 10, and exerts a rotational biasing force in a direction in which the butterfly valve 30 closes.
3, the contact lever 41c is brought into contact with an adjustment screw 11c provided on the throttle body 10 by the rotational biasing force of the coil spring 42. Therefore, by appropriately adjusting the extension amount of the adjustment screw 11c, the valve opening degree of the butterfly valve 30 in the stop position can be set to a desired position.

As shown in Figures 3 to 6, the adjustment valve 50 includes a valve body 51, an electromagnetic actuator 52 equipped with a lead screw that drives the valve body 51 so that it can move back and forth in a direction parallel to the axis S, and a retaining member 53 that fixes the electromagnetic actuator 52 to the throttle body 10.
The adjusting valve 50 adjusts the flow rate of the intake air flowing through the bypass passage 14 by increasing or decreasing the passage area of the bypass passage 14 (communication passage) when the engine is in the idle operating range.

As shown in FIG. 7 , the angular position sensor 60 is provided in a sensor unit U, is formed into a cylindrical shape with a Hall element embedded therein, and detects the rotation angle of the rotating shaft 20 in cooperation with a permanent magnet 24 a disposed in a bottomed cylindrical portion 24 connected to the rotating shaft 20.
7, the pressure sensor 70 is provided in a sensor unit U and includes a pressure receiving portion, such as a diaphragm equipped with a semiconductor strain gauge, a protective cover, etc. The pressure sensor 70 detects the pressure of the intake air through a detection port 16 communicating with the main passage 12.
Here, since the detection port 16 is formed at a position away from the branch port 17a of the auxiliary passage 17 in the direction of the center line L and in the circumferential direction around the center line L, the intake pressure can be detected without being affected by the intake flow in the vicinity of the branch port 17a.
7, the temperature sensor 80 is a reed-type sensor that is provided in the sensor unit U and includes a temperature-sensing element 81 such as a thermistor. The temperature sensor 80 is housed in a cylindrical portion 82 that protrudes from the body of the sensor unit U and is disposed so as to protrude into the main passage 12 upstream of the butterfly valve 30, and detects the temperature of the intake air.

In the above-described configuration, as shown in FIG. 13 , the inner diameter φD1 of the main passage 12, the inner diameter φD2 of the sub-passage 17, the distance H from the axis S of the rotating shaft 20 to the upstream edge of the branch port 17a in the direction of the center line L, and the inclination angle (angle β) of the center line L2 of the sub-passage 17 with respect to the center line L have the following tendencies.
(1) The inner diameter φD1 of the main passage 12 has a small effect on the flow rate of the sub passage 17.
(2) As the inner diameter φD2 of the bypass passage 17 increases, the proportion of the flow rate through the bypass passage 17 tends to increase.
(3) As the distance H becomes smaller, the proportion of the flow rate through the sub passage 17 tends to increase.
(4) As the angle β becomes smaller, that is, when the angle β extends downstream at an incline rather than perpendicular to the center line L of the main passage 12, the flow rate of the sub passage 17 tends to increase.

For these reasons, it is preferable that the branch port 17a of the secondary passage 17 is located downstream of the axis S of the rotating shaft 20 and immediately downstream of the axis S. It is also preferable that the secondary passage 17 is formed so as to extend downstream at a small inclination angle (angle β) with respect to the center line L of the main passage 12. Furthermore, if it is desired to increase the proportion of the flow rate flowing through the secondary passage 17 in the region where the opening degree of the butterfly valve 30 is small, it is preferable to set the inner diameter φD2 of the secondary passage 17 to a large value. Therefore, it is preferable to set various parameters (φD1, φD2, H, β) so that the intake flow rate flowing through the secondary passage 17 is set according to the specifications of the internal combustion engine E based on the above characteristics.

In the intake system IS configured as described above, a main intake passage 7a defined by the intake pipe 7 between the air cleaner 6 and the throttle device M, a main passage 12 defined by the throttle device M, the main intake passage 7a defined by the intake pipe 7 between the throttle device M and the intake port 3a, and the intake port 3a defined by the cylinder head 3 form a main intake passage that guides intake air to the combustion chamber C and is opened and closed by the intake valve 4a at a position facing the combustion chamber C.
In addition, an auxiliary intake passage is formed by the auxiliary passage 17 defined by the throttle device M, the auxiliary intake passage 8a defined by the auxiliary intake pipe 8 between the throttle device M and the auxiliary port 3b, and the auxiliary port 3b defined by the cylinder head 3, which branches off midway through the main intake passage (main passage 12) and joins the main intake passage (intake port 3a) upstream of the intake valve 4a.

Next, the operation of the internal combustion engine E equipped with the above-mentioned intake system IS will be described.
First, when the internal combustion engine E is in the idle operating range, the butterfly valve 30 is in a closed state with the main passage 12 closed, and the intake air sucked in from the air cleaner 6 flows through the main intake passage 7a and the main passage (main intake passage) 12, flows through the bypass passage 14 so as to bypass the butterfly valve 30, and flows again into the downstream main passage (main intake passage) 12, and together with the fuel injected by the fuel injection valve 9 in the main intake passage 7a, forms an air-fuel mixture and flows into the combustion chamber C via the main intake passage 7a and the intake port (main intake passage) 3a.
In this state, the regulating valve 50 adjusts the passage area of the bypass passage 14 (communication passage) to maintain the idle operation of the internal combustion engine E in a stable state.

On the other hand, when the internal combustion engine E is in an operating range other than the idle operating range (low load to medium load to high load), the butterfly valve 30 opens to open the main passage 12 .
Therefore, the intake air flowing through the main passage 12 flows through the main passage 12 or the sub-passage 17 and is drawn into the combustion chamber C without passing through the bypass passage 14.

In other words, in the low to medium load operating range in which the butterfly valve 30 opens from the fully closed position to a predetermined opening angle θ, the opening area A of the branch port 17a communicating with the main passage 12 upstream of the second half portion 31b of the butterfly valve 30 gradually increases as the butterfly valve 30 rotates.
Therefore, the intake air flowing in from the main passage 12 upstream of the butterfly valve 30 is guided by the second half portion 31b, which is inclined toward the downstream side of the butterfly valve 30, as shown in Figures 11 and 14, and is actively directed toward the branch port 17a and flows into the sub-passage 17.
Here, the intake air flowing from the main passage 12 upstream of the butterfly valve 30 and flowing around the first half portion 31a flows behind the back plate 32 and is disturbed, weakening the flow of intake air through the main passage 12. Therefore, compared to the case where the back plate 32 is not present, the flow rate of the intake air flowing into the secondary passage 17 increases relatively.
As a result, the amount of intake air flowing through the auxiliary intake passage (the auxiliary intake passage 17, the auxiliary intake passage 8a, and the auxiliary port 13b) increases, and a swirl flow (horizontal vortex) is generated in the mixture flowing into the combustion chamber C, as shown in Fig. 15. This swirl flow promotes atomization of the fuel and homogenization of the mixture of intake air and fuel, improving combustion efficiency.

In the high-load operating range where the butterfly valve 30 rotates from the predetermined opening angle θ to the fully open position, the opening area of the branch port 17 does not change, and the butterfly valve 30 becomes parallel to the center line L of the main passage 12. Therefore, as shown in FIG. 12, the intake air flowing through the main passage 12 is almost not directed toward the sub-passage 17 by the butterfly valve 30, and flows downstream in the main passage 12. In particular, since a gap is formed between the opening/closing plate 31 and the back plate 32 of the butterfly valve 30, the intake air flows downstream not only around the butterfly valve 30 but also through the gap. As a result, in the high-load operating range, the amount of intake air flowing through the main intake passage (main intake passage 7a, main passage 12, main intake passage 7a, intake port 3a) increases, the combustion speed increases, and efficient combustion is promoted.

16, when the butterfly valve 30 opens from the fully closed position to the fully open position, the proportion of intake air flowing through the auxiliary intake passage (auxiliary intake passage 17, auxiliary intake passage 8a, auxiliary port 13b) increases in the low to medium load operating range. Also, in the medium to high load operating range, the proportion of intake air flowing through the auxiliary intake passage (auxiliary intake passage 17, auxiliary intake passage 8a, auxiliary port 13b) decreases, and the proportion of intake air flowing through the main intake passage (main intake passage 7a, main passage 12, main intake passage 7a, intake port 3a) increases.
Therefore, in the low to medium load operating range, a swirl flow can be generated in the combustion chamber C, improving combustion efficiency, and in the high load operating range, the high-speed intake air flow rate that mainly flows through the main passage 12 increases, increasing the combustion speed and promoting efficient combustion.

In the throttle device M of the above embodiment, the bypass passage 17 extends in a direction forming an inclination angle (angle β) with respect to the main passage 12. However, as shown in FIG. 17, a bypass passage 117 may be employed which branches perpendicularly to the main passage 12 and then extends downstream.
In this embodiment, as described above, the branch port 117a of the sub-passage 117 is located downstream of the opening/closing plate 31 in the closed state, at a position facing the second half 31b when the butterfly valve 30 opens, and is formed at a position where the opening area A communicating with the main passage 12 upstream of the opening/closing plate 31 increases in accordance with the opening of the butterfly valve 30 until the butterfly valve 30 reaches the predetermined opening angle θ. The branch port 117a of the sub-passage 117 opens into the main passage 12 in a circular shape.

In the intake system IS equipped with the throttle device M according to the embodiment described above, the confluence port _3b1 of the auxiliary intake passage (auxiliary port 3b) is oriented in a direction that generates a swirl flow in the combustion chamber C upstream of the intake valve 4a. However, as shown in FIG. 18, a configuration may be adopted in which the fuel injection valve 9 is disposed so as to inject fuel directly into the combustion chamber C, and the confluence port _113b1 of the auxiliary intake passage (auxiliary port 113b) is oriented in a direction that generates a tumble flow (vertical vortex) in the combustion chamber C upstream of the intake valve 4a.

As described above, the throttle device M of the present invention is applied to an intake system IS of an internal combustion engine E, which includes a main intake passage (7a, 3a) that guides intake air into a combustion chamber C and is opened and closed by an intake valve 4a at a position facing the combustion chamber C, and an auxiliary intake passage (8a, 3b) that branches off from the middle of the main intake passage and merges with the main intake passage (3a) upstream of the intake valve 4a. The throttle device M includes a throttle body 10 that defines a main passage 12 that forms a part of the main intake passage and an auxiliary passage 17 that branches off from the main passage 12 and forms a part of the auxiliary intake passage, and a butterfly valve 3 that rotates about a predetermined axis S to open and close the main passage 12. 0, the butterfly valve 30 has an opening/closing plate 31 having a first half body portion 31a that moves upstream and a second half body portion 31b that moves downstream when the valve is opened, and opens and closes the main passage 12, and a protrusion (in this embodiment, a back plate 32) that protrudes downstream from the first half body portion 31a when the valve is closed, and the branch port 17a of the sub-passage 17 is located downstream of the opening/closing plate 31 in the closed state, and is formed in a position facing the second half body portion 31b when the butterfly valve 30 opens, where an opening area A communicating with the main passage 12 upstream of the opening/closing plate 31 increases in accordance with the opening degree of the butterfly valve 30 until the butterfly valve 30 reaches a predetermined opening degree θ.
According to this, while achieving reduction in the number of parts, simplification of the structure, reduction in cost, reduction in passage resistance, etc., in the low-load to medium-load operating range corresponding to the predetermined opening degree θ, the intake air flowing through the main passage 12 can be guided by the second half 31b of the butterfly valve 30 to actively flow into the secondary passage 17. This increases the flow rate of the intake air flowing through the secondary intake passages (17, 8a, 3b), and actively generates a swirling flow (swirl flow or tumble flow) in the combustion chamber C. In particular, since a protruding portion protruding downstream from the first half 31a is provided, the flow of the intake air flowing behind the first half 31a is disturbed by the protruding portion, and the flow of the intake air flowing through the main passage 12 is weakened. Therefore, the flow rate of the intake air flowing into the secondary passage 17 can be relatively increased.

The protruding portion protruding from the first half portion 31a toward the downstream side is a flat back plate 32 fixed to the opening/closing plate 31 with a predetermined gap therebetween.
This allows the butterfly valve 30 to be lighter in weight than when the protrusion is a solid shape such as a ridge or protuberance, and also improves moldability and manufacturability.

Moreover, the butterfly valve 30 is formed so that intake air can pass between the opening/closing plate 31 and the back plate 32 when in a fully open state.
According to this, when in the fully open state, the intake air can pass between the opening/closing plate 31 and the rear plate 32, thereby reducing the passage resistance compared to when the space between the two is formed as a closed solid member.

The rear plate 32 is formed to have an outer contour corresponding to the first half portion 31 a of the opening/closing plate 31 .
According to this, when the butterfly valve 30 opens from a fully closed state, it is possible to obtain the effect of disturbing the flow of intake air downstream to a predetermined opening range, thereby relatively increasing the flow rate of intake air flowing into the secondary passage 17.

Further, the branch port 17 a of the sub-passage 17 is disposed so as to be located downstream of the axis S in the main passage 12 .
According to this, when the butterfly valve 30 rotates around the axis S and the opening/closing plate 31 opens, the branch port 17a can be easily positioned so that it faces the second half portion 31b moving downstream, and the second half portion 31b of the opening/closing plate 31, which is inclined toward the downstream side, can be effectively used as a guide member for the intake air to guide the intake air to the secondary passage 17.

Further, the main passage 12 has a circular cross section, the sub-passage 17 has a circular cross section, and the branch port 17a of the sub-passage 17 is formed to have a circular or elliptical shape.
According to this, by adopting a passage having an easy-to-machine shape, it is possible to reduce costs and also reduce the passage resistance of the passage through which the intake air flows.

In addition, the branch port 17 a of the sub-passage 17 is disposed so that its center L 2 is located on a plane including the center line L of the main passage 12 and the center line L 3 of the butterfly valve 30 perpendicular to the axis S of the rotating shaft 20 .
According to this, the branch port 17 a is disposed in the center of the main passage 12 and the butterfly valve 30 in the direction of the axis S, so that the intake air can be efficiently guided toward the sub-passage 17 .

The sub-passage 17 is formed so as to extend downstream from the branch port 17 a over a predetermined length at a predetermined inclination angle (angle β) with respect to the center line L of the main passage 12 .
This makes it possible to guide the intake air flowing through the main passage 12 to the sub passage 17 while reducing passage resistance due to bending loss.

The throttle body 10 also has a connector portion 18 that connects a passage member (auxiliary intake pipe 8) that defines the auxiliary intake passage 8a.
According to this, when the throttle device M is disposed midway through the intake system IS, the passage member (auxiliary intake pipe 8) that defines the auxiliary intake passage 8a can be easily assembled, improving workability.

The throttle body 10 also includes a bypass passage 14 that bypasses the butterfly valve 30, and a branch port 17a of the secondary passage 17 is disposed at a position separated from a joining port _14b1 of the bypass passage 14. The throttle body 10 also includes a detection port 16 that detects the pressure in the main passage 12 downstream of the butterfly valve 30, and the branch port 17a of the secondary passage 17 is disposed at a position separated from the detection port 16.
According to this, since the branch port 17a is disposed at a position away from the merging port _14b1 and the detection port 16, mutual influence can be prevented and each can perform its respective functions.

In the intake system IS according to the above embodiment, a configuration has been shown in which a throttle device M equipped with a throttle body 10 is arranged midway through the intake pipe 7, but rather than providing a dedicated throttle body, an intake system may also be configured in which a butterfly valve is arranged in a passage member that defines the main intake passage, and a fuel injection valve is arranged to inject midway through the main intake passage or to inject directly into the combustion chamber.
That is, the intake system may be one comprising a main intake passage, a butterfly valve, an auxiliary intake passage, and a fuel injection valve, in which the butterfly valve has a first half that moves upstream when opened and a second half that moves downstream, and an opening/closing plate that opens and closes the main passage, and a protrusion that protrudes downstream from the first half when closed, and in which the branch port of the auxiliary intake passage is located downstream of the opening/closing plate in the closed state, and is formed in a position facing the second half when the butterfly valve opens, where the opening area communicating with the main intake passage upstream of the opening/closing plate increases in accordance with the opening of the butterfly valve until the butterfly valve reaches a predetermined opening degree.

In the above embodiment, a butterfly valve 30 is shown that employs a back plate 32 as a protrusion that protrudes downstream from the first half 31a in the closed state, but this is not limited to this. A solid ridge or protuberance that protrudes downstream from the first half 31a, or a protrusion of any other shape may be used as long as it acts to disturb the intake air flowing behind the first half 31a.

In the above embodiment, the main intake passage (main passage) and the auxiliary intake passage (auxiliary passage) have a circular cross section, and the branch port of the auxiliary intake passage (auxiliary passage) has a circular or elliptical cross section, but this is not limited to this, and main intake passage (main passage), auxiliary intake passage (auxiliary passage), and branch port having other shapes may be used.

In the above embodiment, the vehicle equipped with the internal combustion engine to which the throttle device and intake system of the present invention are applied is a motorcycle, but the present invention is not limited to this and may be applied to an internal combustion engine installed in an automobile, etc.

As described above, the throttle device and intake system of the present invention can increase the flow rate of intake air flowing through the auxiliary intake passage while achieving a reduction in the number of parts, a simplified structure, lower costs, and reduced passage resistance, and therefore can generate swirling flows such as swirl flows and tumble flows in the combustion chamber, contributing to improved combustion efficiency. Therefore, it is not only applicable to internal combustion engines mounted on motorcycles, but is also useful in internal combustion engines mounted on automobiles or internal combustion engines mounted on other vehicles.

E Internal combustion engine IS Intake system 3a Intake port (main intake passage)
3b, 113b Secondary port (secondary intake passage)
3b ₁ , 113b ₁ Auxiliary intake passage junction 4a Intake valve 7 Intake pipe 7a Main intake passage 8 Auxiliary intake pipe (passage member)
8a: auxiliary intake passage 9: fuel injection valve M: throttle device 10: throttle body 12: main passage (main intake passage)
L: center line of main passage 14; bypass passage 14b _; junction of bypass passage 16; detection port 17, 117; auxiliary passage (auxiliary intake passage)
17a, 117a Branching opening β of sub-passage Angle (inclination angle)
L2 Center line of sub-passage 18 Connector portion 20 Rotation axis S Axis line θ Predetermined opening degree 30 Butterfly valve 31 Opening and closing plate 31a First half portion 31b Second half portion 32 Back plate (protruding portion)
33 Connection L3 Center line of butterfly valve

Claims (21)

A throttle device applied to an intake system of an internal combustion engine including a main intake passage which guides intake air into a combustion chamber and which is opened and closed by an intake valve at a position facing the combustion chamber, and an auxiliary intake passage which branches off from the main intake passage midway and joins the main intake passage upstream of the intake valve, the throttle device comprising: a throttle body which defines a main passage which is a part of the main intake passage and an auxiliary passage which branches off from the main passage and is a part of the auxiliary intake passage; and a butterfly valve which rotates about a predetermined axis to open and close the main passage,
the butterfly valve includes an opening/closing plate having a first half portion that moves upstream and a second half portion that moves downstream when the valve is opened, and that opens and closes the main passage; and a protrusion that protrudes downstream from the first half portion when the valve is closed,
a branch port of the sub-passage is located downstream of the opening/closing plate when the butterfly valve is in a closed state, and faces the second half when the butterfly valve is opened, and is formed at a position where an opening area of the branch port communicating with the main passage upstream of the opening/closing plate increases according to an opening degree of the butterfly valve until the butterfly valve reaches a predetermined opening degree.
A throttle device characterized by: The protruding portion is a flat back plate fixed to the opening/closing plate with a predetermined gap therebetween.
2. The throttle device according to claim 1, wherein the throttle device is a throttle valve. The butterfly valve is formed so that intake air can pass between the opening and closing plate and the back plate when the butterfly valve is in a fully open state.
3. The throttle device according to claim 2. The back panel has an outer contour corresponding to the first half of the opening and closing panel.
3. The throttle device according to claim 2. The branch port of the sub-passage is located downstream of the axis in the main passage.
2. The throttle device according to claim 1, wherein the throttle device is a throttle valve. The main passage has a circular cross section,
The sub-passage has a circular cross section,
The branching port of the sub-passage is circular or elliptical.
2. The throttle device according to claim 1, wherein the throttle device is a throttle valve. The branch port of the sub-passage is disposed so that its center is located on a plane including a center line of the main passage and a center line of the opening and closing plate perpendicular to the axis.
7. The throttle device according to claim 1, wherein the throttle device is a throttle valve. The sub-passage is formed so as to extend downstream from the branch port over a predetermined length at a predetermined inclination angle with respect to a center line of the main passage.
7. The throttle device according to claim 1, wherein the throttle device is a throttle valve. The throttle body has a connector portion that connects a passage member that defines the auxiliary intake passage.
7. The throttle device according to claim 1, wherein the throttle device is a throttle valve. the throttle body includes a bypass passage that bypasses the butterfly valve,
The branch port of the sub-passage is disposed at a position away from the junction port of the bypass passage.
7. The throttle device according to claim 1, wherein the throttle device is a throttle valve. the throttle body includes a detection port that detects a pressure in the main passage downstream of the butterfly valve,
The branch port of the sub-passage is disposed at a position away from the detection port.
7. The throttle device according to claim 1, wherein the throttle device is a throttle valve. a main intake passage that introduces intake air into a combustion chamber and is opened and closed by an intake valve at a position facing the combustion chamber;
a butterfly valve that rotates about a predetermined axis to open and close the main intake passage;
an auxiliary intake passage that branches off from the main intake passage and joins the main intake passage upstream of the intake valve;
a fuel injection valve that injects fuel into the main intake passage or into the combustion chamber,
the butterfly valve includes an opening/closing plate having a first half portion that moves upstream and a second half portion that moves downstream when the valve is opened, and that opens and closes the main passage; and a protrusion that protrudes downstream from the first half portion when the valve is closed,
a branch port of the auxiliary intake passage located downstream of the opening/closing plate when the butterfly valve is in a closed state, facing the second half when the butterfly valve is open, and positioned such that an opening area communicating with the main intake passage upstream of the opening/closing plate increases in accordance with the opening of the butterfly valve until the butterfly valve reaches a predetermined opening degree.
An intake system characterized by: The protruding portion is a flat back plate fixed to the opening/closing plate with a predetermined gap therebetween.
13. The air intake system of claim 12. The butterfly valve is formed so that intake air can pass between the opening and closing plate and the back plate when the butterfly valve is in a fully open state.
14. An air intake system as claimed in claim 13. The back panel has an outer contour corresponding to the first half of the opening and closing panel.
14. An air intake system as claimed in claim 13. a branch port of the auxiliary intake passage is located downstream of the axis in the main intake passage;
13. The air intake system of claim 12. The main intake passage has a circular cross section,
The auxiliary air intake passage has a circular cross section,
The branch port of the auxiliary air intake passage is circular or elliptical.
13. The air intake system of claim 12. The branch port of the auxiliary air intake passage is disposed so that its center is located on a plane including a center line of the main air intake passage and a center line of the opening and closing plate perpendicular to the axis.
18. An air intake system according to any one of claims 12 to 17. The auxiliary air intake passage is formed so as to extend downstream from the branch port over a predetermined length at a predetermined inclination angle with respect to a center line of the main air intake passage.
18. An air intake system according to any one of claims 12 to 17. A joining port of the auxiliary intake passage is oriented in a direction that generates a swirl flow in the combustion chamber, upstream of the intake valve.
18. An air intake system according to any one of claims 12 to 17. A joining port of the auxiliary intake passage is oriented in a direction that generates a tumble flow in the combustion chamber, upstream of the intake valve.
18. An air intake system according to any one of claims 12 to 17.

Images