JP5230480B2 - Engine intake device and saddle-ride type vehicle equipped with the same - Google Patents

Description

  The present invention relates to an engine intake device and a saddle-ride type vehicle including the same.

  Conventionally, an intake device for an engine is configured as follows. The air taken in from the air intake is guided to the air cleaner and purified. The purified air is guided to the throttle body via the intake pipe to adjust the intake air amount. The air whose intake air amount has been adjusted is guided to each intake port of the engine via an intake manifold (see, for example, Patent Document 1).

  The air cleaner includes a filter element that captures dust in the air and an air cleaner box that houses the filter element. When the rotational speed of the engine is increased rapidly, it is necessary to take in a lot of air into the engine accordingly. In this case, the air taken into the engine is only the air accumulated in the air cleaner box. Therefore, in order to improve engine performance, it is desirable that the capacity of the air cleaner, that is, the capacity of the air cleaner box located downstream of the filter element is as large as possible.

  On the other hand, it is known that the air flowing in the intake path from the air cleaner to the intake port of the engine is a pressure wave (pulsating flow) having a low air pressure portion and a high air pressure portion. Therefore, when the intake air velocity reaches its maximum (immediately before the intake valve closes), if the high intake air pressure (positive pressure wave) reaches the intake port, the intake inertia effect is maximized and volume efficiency is improved. Can do.

  Here, it is known that the following relationship exists between the length of the intake path (intake path length) and the pulsating flow in the intake path. That is, the longer the intake path length, the longer the wavelength of the pulsating flow, and the shorter the intake path length, the shorter the wavelength of the pulsating flow. Further, it is known that the following relationship exists between the engine speed and the intake path length. That is, if the engine speed increases, the pulsating flow period becomes shorter, and if the engine speed decreases, the pulsating flow period becomes longer. Therefore, it is desirable that the intake path length is long in the low engine speed region, and it is desirable that the intake path length is short in the high engine speed region.

  However, since the intake path length is usually constant, an increase in intake air amount due to the intake inertia effect can be obtained in a specific engine speed region, but no intake inertia effect can be obtained in other engine speed regions. become. As a result, a so-called “torque valley” occurs in which the engine output decreases in an engine speed range where the intake inertia effect cannot be obtained.

  As a technique for improving the output characteristics of the engine by avoiding such “torque valley”, an apparatus that changes the intake path length according to the engine speed has been proposed (for example, Patent Document 2). To 4).

(1) Technology of Patent Document 2 The device described in Patent Document 2 forms an opening at an intermediate height position of the intake pipe, and slidably fits a movable pipe to the intake pipe, and this movable pipe Is slid according to the engine speed to open and close the opening of the intake pipe.

(2) Technology of Patent Document 3 The device described in Patent Document 3 is provided with a plurality of curved intake rods arranged side by side in a surge tank, and auxiliary ports are slidably fitted to these curved intake rods. These auxiliary ports are slid according to the engine speed.

(3) Technology of Patent Document 4 In the device described in Patent Document 4, a plurality of auxiliary manifolds are movably linked to one end side of an intake manifold introduced into a surge tank, and these auxiliary manifolds are connected to an engine speed. It is moved according to.

Japanese Patent No. 3723792 (pages 3-4, FIGS. 3-5) JP 2008-19816 (pages 6-7, FIG. 5 and FIG. 6) JP-A-8-338251 (pages 4-5, FIGS. 1 and 2) Japanese Patent Laid-Open No. 9-222018 (pages 4-5, FIG. 1)

  However, in the case of the technique described in Patent Document 1, since the air cleaner is arranged in a narrow space around the engine, it is difficult to increase the size of the air cleaner. As a result, there is a problem that the capacity of the air cleaner is insufficient and the output of the engine is reduced in a high rotation range. Such a problem is conspicuous in a motorcycle that has many restrictions on the vehicle layout and that frequently starts up the engine speed to a high speed range.

  On the other hand, in the case of the techniques described in Patent Documents 2 to 4, it is difficult to significantly change the intake path length in a limited space such as a surge tank. Therefore, the intake inertia effect cannot be obtained over a wide engine speed range. In particular, since the change in engine speed is large in a motorcycle, the technology described in Patent Documents 2 to 4 is not very effective for a motorcycle in consideration of the necessity of greatly changing the intake path length. I can't say that.

  The present invention has been made in view of such circumstances, and it is possible to increase the capacity of an air cleaner, and to obtain an intake air inertia effect over a wide engine speed range and an engine air intake device therefor An object of the present invention is to provide a saddle-ride type vehicle equipped with a vehicle.

In order to achieve the above object, the present invention has the following configuration.
That is, the engine intake device according to the first aspect of the present invention includes a filter element that purifies the air taken in, an air cleaner box that stores clean air that has passed through the filter element, and the air cleaner box that communicates with the air cleaner box. A box in a frame provided in a space in a vehicle body frame for storing air, an intake pipe having one end communicating with the air cleaner box and the box within the frame, and the other end communicating with an intake port of the engine, and the air cleaner A first valve for controlling an air flow flowing directly from the box to the intake pipe; a second valve for controlling an air flow flowing from the air cleaner box to the intake pipe via the box in the frame; and an operating state of the engine And a controller for controlling the first and second valves according to To have.

  According to the first aspect of the present invention, the control unit controls the first and second valves according to the operating state of the engine, so that the clean air stored in the air cleaner box, the box in the frame, or both boxes is stored. Is sent to the intake port of the engine via the intake manifold. Therefore, according to the first aspect of the present invention, since the box in the frame for storing clean air is provided in the space in the vehicle body frame, it is difficult to increase the capacity of the air cleaner box due to restrictions on the vehicle layout. However, the capacity of the air cleaner (here, the total capacity of the air cleaner box and the box in the frame) can be increased by the capacity of the box in the frame. Further, since the space in the vehicle body frame is relatively large and has room, it is easy to increase the size of the box in the frame. As a result, a sufficient capacity of the air cleaner can be secured, and a high engine output can be obtained even in a high rotation range.

  Further, since the air cleaner box is usually placed in a narrow space around the engine, the intake path from the air cleaner box to the intake port of the engine via the intake manifold is relatively short. On the other hand, when an in-frame box is provided in the space in the vehicle body frame, the intake path from the air cleaner box through the in-frame box to the intake port of the engine via the intake manifold becomes relatively long. Therefore, according to the first aspect of the present invention, the intake path length can be significantly changed by appropriately controlling the first and second valves. As a result, an intake inertia effect can be obtained over a wide engine speed range.

  In the present invention, preferably, a plurality of boxes in the frame are provided (the invention according to claim 2). By providing a plurality of boxes in the frame, the capacity of the air cleaner can be further increased, and the change width of the intake path length can be further increased.

  Preferably, in the present invention, the vehicle body frame includes a pair of main frames extending in a traveling direction, the air cleaner box is disposed between the pair of main frames, and the box in the frame sandwiches the air cleaner box. , And are respectively disposed in the spaces in the pair of main frames (the invention according to claim 3). According to this configuration, the arrangement of the air cleaner box and the pair of frames in the frame can be made compact.

  In the present invention, preferably, a plurality of the in-frame boxes are provided on each of the pair of main frames (the invention according to claim 4). According to this configuration, it is possible to further increase the capacity of the air cleaner and to increase the change width of the intake path length.

  Preferably, in the present invention, the air cleaner box communicates with one end side of the intake pipe at the center of the bottom portion thereof, and communicates with the front side in the running direction of the box in the frame via the first connecting pipe at both side portions thereof. And the running direction rear side of the box in the frame communicates with one end side of the intake pipe via a second connecting pipe (the invention according to claim 5). According to this configuration, the air flowing into the box in the frame flows through the box in the frame from the front side in the running direction to the rear side in the running direction, so that the air flow in the box in the frame becomes smooth.

  In the present invention, the box in the frame is preferably made of rubber (the invention according to claim 6). According to this structure, the vibration and noise by the air which distribute | circulates the box in a flame | frame can be suppressed.

  Preferably, in the present invention, the first valve is disposed at a first outlet of the air cleaner box from which an air flow flows directly from the air cleaner box to the intake pipe, and the second valve is disposed in the air cleaner box. It is arrange | positioned at the 2nd outflow port of the said air cleaner box from which an air flow flows out to the said box in a flame | frame (invention of Claim 7). According to this configuration, by opening the first outlet and closing the second outlet, the air flowing through the air cleaner box can be smoothly led directly to the intake manifold. Moreover, the air which distribute | circulates an air cleaner box can be smoothly guide | induced to the box in a flame | frame by closing a 1st outflow port and opening a 2nd outflow port.

  Preferably, in the present invention, the first and second valves are opened and closed by an electric motor so that the opening of the valves can be adjusted (the invention according to claim 8). According to this configuration, by adjusting the opening degree of the first and second valves, the air flows from the air cleaner box directly to the intake manifold, and the air flows from the air cleaner box to the intake manifold through the box in the frame. It is possible to adjust the air flow in a complicated manner, such as adjusting the air flow rate by flowing air through both paths at the same time, as well as the alternative of the intake air flow. Thus, the length of the intake path can be accurately changed.

  Preferably, in the present invention, the control unit executes a normal control mode in a normal operation state of the engine and a special control mode for suppressing a decrease in engine output in a specific engine speed range, and performs the normal control. In the mode, control is performed so that air is circulated through at least the box in the frame (the invention according to claim 9). Since the length of the box in the frame can be secured relatively freely, an optimum intake path length can be easily achieved in the normal control mode if air is passed through the box in the normal control mode. can do.

  In the present invention, preferably, the control unit controls the first and second valves in accordance with the rotational speed of the engine (the invention according to claim 10). The intake inertia effect varies depending on the engine speed, particularly in the engine operating state. Therefore, by changing the intake path length by controlling the first and second valves according to the engine speed, Accurate control can be performed.

  In the present invention, preferably, the control unit further controls the first and second valves in accordance with a throttle opening degree. Since the intake inertia effect is also affected by the throttle opening, more accurate control can be performed by changing the intake path length by controlling the first and second valves according to the throttle opening.

  The engine intake device according to the present invention is preferably mounted on a saddle-ride type vehicle (the invention according to claim 12). A saddle-ride type vehicle has many restrictions on the vehicle layout, and it is difficult to increase the size of the air cleaner or to greatly change the intake path length. Therefore, the saddle-ride type vehicle is suitable as a vehicle equipped with the engine intake device according to the present invention. is there.

  The engine intake device according to the present invention is particularly preferably mounted in a motorcycle, and the box in the frame is formed in a space in a pair of main frames branched in a bifurcated manner from a head pipe through which a steering shaft is inserted. (Invention of claim 13). Since motorcycles often start up the engine speed rapidly to a high speed range, it is desirable to increase the size of the air cleaner and expand the change range of the intake path length. Therefore, a motorcycle is particularly suitable as a vehicle on which the engine intake device according to the present invention is mounted. In the motorcycle, if the intra-frame box is disposed in the space in the pair of main frames branched in a bifurcated manner from the head pipe through which the steering shaft is inserted, the present invention can be implemented easily and suitably.

  According to the present invention, since the box in the frame for storing clean air is provided in the space in the vehicle body frame, even if it is difficult to increase the capacity of the air cleaner box due to restrictions on the vehicle layout, The capacity of the air cleaner can be increased by the capacity. Further, since the space in the vehicle body frame is relatively large and has room, it is easy to increase the size of the box in the frame. As a result, according to the present invention, the capacity of the air cleaner can be sufficiently secured, and a high engine output can be obtained even in a high rotation range.

  Further, since the air cleaner box is usually placed in a narrow space around the engine, the intake path from the air cleaner box to the intake port of the engine via the intake manifold is relatively short. On the other hand, when an in-frame box is provided in the space in the vehicle body frame, the intake path from the air cleaner box through the in-frame box to the intake port of the engine via the intake manifold becomes relatively long. Therefore, according to the present invention, the intake path length can be significantly changed by appropriately controlling the first and second valves. As a result, an intake inertia effect can be obtained over a wide engine speed range, and a good engine output characteristic without so-called torque valleys can be obtained.

1 is a side view showing a schematic configuration of a motorcycle according to a first embodiment. 1 is a perspective view showing a main part configuration of an intake device according to Embodiment 1. FIG. FIG. 3 is a horizontal sectional view of the intake device shown in FIG. 2. FIG. 3 is a longitudinal sectional view of the intake device shown in FIG. 2. FIG. 3 is a block diagram illustrating a configuration of a control system of the intake device according to the first embodiment. It is the figure which showed the relationship between the rotation speed of an engine, and the output characteristic of an engine. It is a schematic diagram of a valve opening degree setting table. 3 is a flowchart showing a control operation of the intake device. FIG. 6 is a horizontal sectional view of an intake device according to Embodiment 2.

Embodiment 1 of the present invention will be described below with reference to the drawings.
Here, a motorcycle will be described as an example of the saddle-ride type vehicle including the engine intake device according to the first embodiment.

(1) Overall Schematic Configuration FIG. 1 is a side view illustrating a schematic configuration of a motorcycle according to a first embodiment. Note that PV in FIG. 1 is a partial view of the periphery of the main frame in plan view.

  The motorcycle 1 has a pair of main frames 4R and 4L bifurcated from a head pipe 3 through which the steering shaft 2 is inserted (hereinafter, the main frames 4R and 4L are denoted by reference numeral “4” unless otherwise distinguished). It has. A steering handle 5 is connected to the upper end portion of the steering shaft 2, and a pair of front forks 6 are connected to the lower end portion thereof. A front wheel 7 is rotatably attached to a lower end portion of the front fork 6. A front end portion of a pair of swing arms 8 is swingably attached to the rear side portion of the main frame 4. A rear wheel 9 is rotatably attached to the rear end portion of the swing arm 8. An engine 10 is mounted on the lower side of the main frame 4. The driving force generated by the engine 10 is transmitted to the rear wheel 9 via the transmission 11, the drive shaft 12, the drive sprocket 13, the chain 14, and the driven sprocket 15. A fuel tank 16 is provided above the engine 10 across the main frame 4, and a seat 17 is provided behind the fuel tank 16.

(2) Configuration of Intake Device The configuration of the intake device provided in the motorcycle 1 will be described with reference to FIGS. 1 and 2 to 4. 2 is a perspective view showing a configuration of a main part of the intake device, FIG. 3 is a horizontal sectional view of the intake device shown in FIG. 2, and FIG. 4 is a longitudinal sectional view of the intake device shown in FIG.

  The intake device 20 includes an air funnel 21 that takes in air, a filter element 22 that filters air taken in from the air funnel 21 (see FIG. 4), an air cleaner box 23 that stores clean air that has passed through the filter element 22, and an air cleaner. Two in-frame boxes 24R and 24L respectively provided in the space in the pair of main frames 4 that communicate with the box 23 and store clean air (hereinafter, the two boxes 24R and 24L are designated by the symbol “ 24 ”). The main frame 4 corresponds to the vehicle body frame in the present invention.

  As shown in FIG. 4, the air funnel 21 includes an opening 21 a that opens toward the traveling direction. A filter element 22 is disposed at a communication portion between the air funnel 21 and the air cleaner box 23. As shown in FIGS. 2 and 3, the air cleaner box 23 is a substantially trapezoidal box in plan view, and is disposed between the pair of main frames 4. As shown in FIGS. 3 and 4, a first outlet 25 from which an air flow flows is formed at the bottom center of the air cleaner box 23 on the rear side in the traveling direction. Further, the second outlets 26R, 26L from which the airflow flows toward the front side of the both sides along the traveling direction of the air cleaner box 23 (hereinafter, the sign “26” is used unless the second outlets 26R, 26L are particularly distinguished). Are attached to each other.

  The configuration of the pair of intra-frame boxes 24 (24R, 24L) will be described. In the following, description will be given by taking the in-frame box 24R on the right side facing the traveling direction as an example. The in-frame box 24R is formed in a form corresponding to the internal space of the main frame 4R, and is a rectangular parallelepiped box in the embodiment. The in-frame box 24R is formed of rubber in order to prevent vibration and noise due to airflow. An air flow inlet 27R is formed on the front side in the running direction of the side facing the air cleaner box 23 of the in-frame box 24R. The second outlet 26R of the air cleaner box 23 is connected to the inlet 27R of the in-frame box 24R via a first rubber connecting pipe 28R. An air flow outlet 29R is formed on the rear side in the running direction of the side surface of the in-frame box 24R facing the air cleaner box 23.

  One end side of the intake pipe 30 is connected to the first outlet 25 of the air cleaner box 23. The other end of the intake pipe 30 is connected to the intake port of the engine 10. In addition, one end of a second rubber connecting pipe 31R is connected to the outlet 29R of the in-frame box 24R. The second connecting pipe 31R is guided to the center along the bottom surface of the air cleaner box 23, and the other end thereof is connected to one end side of the intake pipe 30 in the vicinity of the first outlet 25 of the air cleaner box 23. .

  A first valve 32 that controls the air flow flowing from the air cleaner box 23 to the intake pipe 30 is provided at the first outlet 25 of the air cleaner box 23. The first valve 32 is configured to be adjustable in opening by an electric motor 33. Similarly, a second valve 34R for controlling the air flow flowing from the air cleaner box 23 to the in-frame box 24R is provided at the second outlet 26R of the air cleaner box 23. The second valve 34R is configured to be adjustable in opening by an electric motor 35R.

  Since the configuration of the in-frame box 24L on the left side facing the traveling direction and the surrounding configuration are the same as the above-described configuration of the in-frame box 24R and the surrounding configuration, description thereof is omitted here. In the following description, when the left and right frame boxes 24R and 24L are described separately from the surrounding components, the reference numerals are suffixed with “R” or “L”. When not distinguished, the explanation will be made with the subscript omitted.

(3) Configuration of Control System of Intake Device The configuration of the control system of the intake device 20 will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the control system of the intake device 20.

  The intake device 20 includes an ECU (Engine Control Unit) 40 that controls the first valve 32 and the pair of second valves 34 of the air cleaner box 23 according to the operating state of the engine 10. The ECU 40 corresponds to the control unit in the present invention. The ECU 40 is supplied with a detection signal from a throttle opening detection sensor 41 that detects the opening of the throttle valve. Further, the ECU 40 is supplied with a detection signal from a rotation speed detection sensor 42 that detects the rotation speed of the engine 10. The ECU 40 refers to the valve opening setting table stored in advance in the memory 43 based on the detection signals of the throttle opening detection sensor 41 and the rotation speed detection sensor 42, and the first valve 32 and the pair of second valves 34. The opening of each is determined individually.

Here, the relationship between the engine speed and the engine output characteristics will be described with reference to FIG.
As described above, when the intake path length is constant, an increase in intake air amount due to the intake inertia effect can be obtained in a specific engine speed region, but no intake inertia effect can be obtained in other engine speed regions. . As a result, a so-called “torque valley” occurs in which the engine output decreases in an engine speed range where the intake inertia effect cannot be obtained. In FIG. 6, the P1 and P2 regions are “torque valleys”. The P3 region is not a clear “torque valley”, but the increase in output is slow, which is not preferable as engine output characteristics. As shown in the characteristic diagrams of the loads 1 to 3 in FIG. 6, the engine speed region in which the “torque valley” occurs varies depending on the load acting on the engine. The engine load can be detected by the opening of the throttle valve. That is, in order to avoid the “torque valley”, it is preferable to change the intake path length in accordance with the engine speed and the throttle valve opening.

  Therefore, in this embodiment, the valve opening setting tables 43a to 43d as shown in FIG. The tables 43a to 43d are provided for each region of the opening degree θ of the throttle valve, and the opening amounts of the first valve 32 and the pair of second valves 34 are individually set according to the region of the engine speed n. Has been. The first valve 32 and the pair of second valves 34 can be set by simple opening / closing information. However, if the setting is made by opening (angle) information of each valve as in the present embodiment, the air flow is complicated. Since the flow can be adjusted, the substantial length of the intake path can be accurately changed according to the operating state of the engine.

(4) Control Operation of Intake Device The operation of the intake device according to the present embodiment will be described with reference to FIG.
Step S1: The ECU 40 captures the throttle valve opening from the throttle opening detection sensor 41 and the rotation speed of the engine 10 from the rotation speed detection sensor 42, respectively.

  Step S2: The ECU 40 determines whether to adopt the normal control mode or the special control mode based on the throttle opening and the engine speed taken in from each of the sensors 41 and 42. In the present specification, the “normal control mode” means a control mode of the intake device when the engine 10 is in a normal operation state. For example, in FIG. 6, the control mode is in a rotational speed region excluding a specific rotational speed region in which a so-called “torque valley” (regions P1, P2, and P3 in FIG. 6) occurs. The “special control mode” means a control mode for suppressing a decrease in engine output (torque trough) in a specific engine speed range.

(5) Normal control mode Step S3: In the present embodiment, in the normal control mode, an air flow is made to flow mainly through the pair of boxes 24 in the frame. Since the space in the main frame 4 has a relatively large space, the length and volume of the pair of in-frame boxes 24 provided in the main frame 4 can be relatively freely secured. Therefore, it is possible to relatively easily realize an optimal intake path length that is unlikely to cause a decrease in engine output. By setting the optimum intake path length in advance, it is possible to suppress the occurrence of a specific rotation speed region in which “torque valley” occurs as much as possible, so the mode shifts to the special control mode (that is, the intake path length is changed). The number of times can be reduced, and the intake device can be easily controlled accordingly. In the normal control mode, the first valve 32 may not be completely closed, but the first valve 32 may be opened slightly to allow the air flow from the air cleaner box 23 to flow directly to the intake pipe 30. Whether to use the pair of in-frame boxes 24 alone or in combination with the air cleaner box 23 is determined in advance by experiments so that the best engine output characteristics can be obtained.

(6) Special control mode Step S4: In the special control mode, the intake path length is changed to suppress the output decrease in the specific rotation speed region that causes the engine output to decrease in the normal control mode. Specifically, the ECU 40 refers to the valve opening setting tables 43a to 43d in the memory 43, and opens the first valve 32 and the second valves 34R and 34L according to the current throttle opening and the engine speed. Is read and the opening of each valve 32, 34R, 34L is adjusted. As a result, the intake path length substantially changes and is set to an optimum intake path length according to the operating state of the engine at that time, so that a decrease in engine output can be suppressed. Note that the usage mode of the pair of in-frame box 24 and the air cleaner box 23 in the special control mode is also experimentally determined. Alternatively, the second valves 34R and 34L may be set at different opening degrees so that the amounts of air flowing through the in-frame boxes 24R and 24L are different from each other.

  As described above, according to the first embodiment, in addition to the air cleaner box 23, the frame inner box 24 is provided in the space in the main frame 4, so the capacity of the air cleaner (here, the air cleaner box 23 and the frame inner box) The sum of the capacities of 24) can be increased. As a result, a sufficient capacity of the air cleaner can be secured, and a high engine output can be obtained even in a high rotation range.

  When the in-frame box 24 is provided, the intake path from the air cleaner box 23 through the in-frame box 24 to the intake port of the engine via the second connecting pipe 31 and the intake rod 30 becomes relatively long. As a result, by appropriately adjusting the opening degree of the first valve 32 and the second valves 34R and 34L, it is possible to change the intake path length over twice as long as compared with the shortest and longest. As a result, an intake inertia effect can be obtained over a wide engine speed range.

An engine intake apparatus according to Embodiment 2 will be described with reference to FIG.
FIG. 9 is a horizontal sectional view of the intake device for the engine according to the second embodiment. In FIG. 9, the parts denoted by the same reference numerals as those shown in FIG. 3 have the same configuration as that of the first embodiment, and thus the description thereof is omitted here.

  The feature of the present embodiment is that each of the pair of main frames 4 is provided with other intra-frame boxes 44R and 44L in addition to the intra-frame boxes 24R and 24L described in the first embodiment. The in-frame box 44R provided in the main frame 4R is connected to the air cleaner box 23 through the first connecting pipe 45R on the front side in the traveling direction. The in-frame box 44R is connected to the intake pipe 30 through the second connecting pipe 46R on the rear side in the traveling direction. A third valve 49R whose opening degree is adjusted by an electric motor 48R is provided at an outlet 47R for flowing an air flow from the air cleaner box 23 to the in-frame box 44R. Similarly, the main frame 4L is provided with an in-frame box 44L, and the in-frame box 44L communicates with the air cleaner box 23 through the first connecting pipe 45L and with the intake pipe 30 through the second connecting pipe 46L. It is connected. A third valve 49L whose opening degree is adjusted by an electric motor 48L is provided at the outlet 47L for flowing an air flow from the air cleaner box 23 to the box 44L in the frame.

  According to the second embodiment, since the two in-frame boxes 24R and 44R (or 24L and 44L) are provided in the pair of main frames 4, respectively, the capacity of the air cleaner can be further increased. Further, by appropriately opening and closing each of the valves 32, 34R, 34L, 49R, 49L, it is possible to further increase the range of change in the intake path length as compared with that of the first embodiment, thereby further widening the engine. An intake inertia effect can be obtained over the rotational speed range.

The present invention is not limited to those of the first and second embodiments, and can be modified as follows.
(1) Each of the pair of main frames 4 may be provided with three or more in-frame boxes.

  (2) In the above embodiment, the intake path length is adjusted according to the throttle opening and the engine speed as the engine operating state, but the intake path length may be adjusted only according to the engine speed.

  (3) The operating state of the engine is not limited to the throttle opening and the engine speed, and for example, the mixture ratio of gasoline and air may be detected, and the intake path length may be adjusted in consideration of the mixture ratio. .

  (4) Further, as the engine operating state, the intake path length may be adjusted in consideration of the ignition timing of the engine.

  (5) In the above embodiment, the box in the frame is formed of rubber, but a closed space may be formed by a metal inner wall in the main frame, and this may be used as the box in the frame.

  (6) In the above embodiment, the example in which the engine intake device according to the present invention is mounted on a motorcycle has been described. However, the engine intake device according to the present invention may be a vehicle having a body frame having an internal space. For example, the present invention can be applied to other saddle-ride type vehicles and automobiles.

4 (4R, 4L) ... Main frame 20 ... Intake device 21 ... Air funnel 23 ... Air cleaner box 24 (24R, 24L) ... Frame inner box 25 ... First outlet 26 (26R, 26L) ... Second outlet 27 ( 27R, 27L) ... Inlet 28 (28R, 28L) ... First connecting pipe 29 (29R, 29L) ... Outlet 30 ... Intake pipe 31 (31R, 31L) ... Second connecting pipe 32 ... First valve 33 ... Electric Motor 34 (34R, 34L) ... Second valve 35 (35R, 35L) ... Electric motor 40 ... ECU
41 ... Throttle opening detection sensor 42 ... Rotation speed detection sensor 43 ... Memory 44 (44R, 44L) ... In-frame box

Claims (13)

A filter element for purifying the air taken in;
An air cleaner box for storing clean air that has passed through the filter element;
An in-frame box provided in a space in a vehicle body frame for storing the clean air in communication with the air cleaner box;
An intake pipe having one end communicating with the air cleaner box and the box within the frame and the other end communicating with an intake port of the engine;
A first valve for controlling an air flow flowing directly from the air cleaner box to the intake pipe;
A second valve for controlling an air flow from the air cleaner box to the intake pipe via the box in the frame;
An engine intake device comprising: a control unit that controls the first and second valves in accordance with an operating state of the engine. The engine intake device according to claim 1,
The in-frame box has a plurality of engine intake devices The engine intake device according to claim 2,
The vehicle body frame includes a pair of main frames extending in the traveling direction,
The air cleaner box is disposed between the pair of main frames,
The in-frame box is an engine intake device that is disposed in a space in the pair of main frames with the air cleaner box interposed therebetween. The engine intake device according to claim 3,
A plurality of the in-frame boxes are engine intake devices provided on each of the pair of main frames. The engine intake device according to claim 3 or 4,
The air cleaner box communicates with one end side of the intake pipe at the bottom center portion thereof, and communicates with the front side in the running direction of the box in the frame via the first connecting pipe on both side portions thereof,
An intake device for an engine, wherein a rear side in the traveling direction of the box in the frame communicates with one end side of the intake pipe via a second connecting pipe. The engine intake device according to any one of claims 1 to 5,
The box in the frame is an engine intake device made of rubber. The engine intake device according to claim 1,
The first valve is disposed at a first outlet of the air cleaner box, in which an air flow flows directly from the air cleaner box to the intake pipe,
The second valve is an intake device for an engine disposed at a second outlet of the air cleaner box through which an air flow flows from the air cleaner box to the box in the frame. The engine intake device according to claim 7,
The first and second valves are engine intake devices that are opened and closed by an electric motor so that the opening of the valves can be adjusted. The engine intake device according to claim 1,
The control unit executes a normal control mode in a normal operating state of the engine and a special control mode for suppressing a decrease in engine output in a specific engine speed range, and in the normal control mode, at least the frame Engine intake system that performs control by circulating air through the inner box. The engine intake device according to claim 1,
The control unit is an engine intake device that controls the first and second valves in accordance with the rotational speed of the engine. The engine intake device according to claim 10,
The control unit is an engine intake device that further controls the first and second valves in accordance with a throttle opening.   A saddle-ride type vehicle comprising the engine intake device according to any one of claims 1 to 10. The saddle-ride type vehicle according to claim 12,
The saddle riding type vehicle is a motorcycle,
The in-frame box is a saddle-ride type vehicle disposed in a space in a pair of main frames branched from a head pipe through which a steering shaft is inserted.

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