JP2004197656A - Variable intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To meet constraints on an engine room layout, allow the entrainment of inertial effects in the low and high rotation regions of an engine and prevent the deterioration of output performance. <P>SOLUTION: An intake passage for distributing intake air in a collector 3 of a intake manifold 2 into each cylinder is changed over between a short port (L1) constituted by a first port 7 and a long port (L3=L1+L2) constituted by the first port 7 and a second port 8 with the second port 8 connected in series to the upstream side of the first port 7 by the opening/closing of a variable intake valve 9. A passage cross section area B of the second port 8 is smaller than a passage cross section area A of the first port 7. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable intake device for an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a variable intake device for an internal combustion engine, as shown in Patent Document 1, an intake passage for distributing intake air in a collector of an intake manifold to each cylinder in accordance with an engine rotation range is provided by a first variable intake valve. Switch between a short port consisting of a port and a long port consisting of a first port and a second port with a second port connected in series upstream of the first port to change the inertia and pulsation effects It is known that the volumetric efficiency of the engine is improved by performing the above.
[0003]
[Patent Document 1]
JP-A-2002-147299
[Problems to be solved by the invention]
However, in the device described in Patent Literature 1, since the passage cross-sectional areas of the first port and the second port are formed substantially constant, for example, in the case of a V-type engine, a long port (The total path length of the first port and the second port) cannot be sufficiently secured, and the inertia effect cannot be tuned in the low engine speed range. On the other hand, if the passage length of the first port and the second port is reduced and the port length is increased in order to satisfy the layout restriction, the inertia effect can be tuned in the low engine speed range. When switching to the short port (first port) is performed in the range, the pressure loss at the short port increases, and thus a problem has arisen that the output performance decreases.
[0005]
The present invention has been made in view of the above problems, and has as its object to satisfy the constraint conditions of the engine room layout, tune the inertia effect in the low engine speed range and the high engine speed range, and prevent a decrease in output performance. .
[0006]
[Means for Solving the Problems]
Therefore, in the present invention, the passage sectional area of the second port is made smaller than the passage sectional area of the first port.
[0007]
【The invention's effect】
According to the present invention, by switching the variable intake valve, the inertia effect can be tuned in the low engine speed range and the high engine speed range, and the pressure loss at the first port in the high engine speed range and the passage cross-sectional area can be increased. By doing so, it is possible to prevent a decrease in output performance. On the other hand, by reducing the passage cross-sectional area of the second port, the passage length of the second port can be ensured even when the engine room layout is severely restricted. (Total path length with the second port) can be secured, and a tuning effect in a low rotation range can be obtained.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing an intake manifold 2 including a variable intake device 1 for an internal combustion engine according to the first embodiment.
[0009]
An intake manifold 2 extends between banks of a V-type engine (not shown) in the direction of the cylinders, and a collector 3 to which intake air is guided through a throttle valve (not shown). An intake pipe 4 is provided which extends and distributes intake air in the collector 3 to each cylinder. The outlet side flange portion 5 of the intake pipe 4 is fixed to a cylinder head (not shown) to form an intake passage to an intake valve (not shown).
[0010]
Here, an intake passage (collectively including a passage in the intake pipe 4 and a passage in the cylinder head) that distributes intake air in the collector 3 of the intake manifold 2 to each cylinder has a downstream length L1. It has a first port 7 having a cross-sectional area A and a second port 8 having a passage cross-sectional area B having a length L2 on the upstream side. The length L1 of the first port 7 includes the length to the intake valve.
[0011]
The first port 7 and the second port 8 are configured to communicate with the collector 3 at an inlet 7a of the first port 7 and an inlet 8a of the second port 8, which are connecting portions thereof. A variable intake valve (opening / closing valve) 9 that can open and close the inlet 7a and the communicating portion between the collector 3 and the collector 3 is provided. Although the variable intake valve 9 is provided for each cylinder, it is attached to a common rotary shaft 10 arranged in the direction in which the collector 3 extends, and the rotation of the rotary shaft 10 causes the inlet portions 7a of the first ports 7 to rotate. Open and close at the same time. The rotation shaft 10 is rotated by a variable intake control actuator (not shown).
[0012]
Therefore, when the variable intake valve 9 is opened or closed, the intake passage is switched to a short port (passage length L1) constituted by the first port 7 when the variable intake valve 9 is opened, and when the variable intake valve 9 is closed, the intake passage is switched to the first port 7. The second port 8 is connected in series on the upstream side, and can be switched to a long port (passage length L3 = L1 + L2) formed by the first port 7 and the second port 8.
[0013]
The first port 7 has a passage cross-sectional area having an area A as shown in the figure. On the other hand, as shown in the drawing, the second port 8 is formed with an area B whose passage sectional area is smaller than the passage sectional area A of the first port 7. For this reason, even if the size of the engine room is the same, the second port 8 is made longer by making the second port 8 thinner (reducing the passage cross-sectional area B) as compared with the conventional device. Can be. For example, even in a V-type engine in which port layout restrictions are severe or a sporty car engine with a low hood, it is possible to improve low-speed torque in a low engine speed range without deteriorating output performance in a high engine speed range.
[0014]
That is, in a high engine speed region where a large amount of intake air to the cylinder is required, the variable intake valve 9 is opened by a variable intake control actuator (not shown), and the intake air in the collector 3 is supplied to the inlet 7 a of the first port 7. The operation is performed in a state where the air is introduced into the cylinder through the first port 7 and guided to the cylinder. In this operating state, the length of the effective intake port is from the variable intake valve 9 to the intake valve, that is, the length L1 of the first port 7, and this short port provides an intake inertia effect in a higher rotation range. In addition, the torque can be improved (the maximum output can be improved).
[0015]
On the other hand, in an engine low-medium rotation region where a large amount of intake air to the cylinder is not required, the variable intake control actuator closes the variable intake valve 9 and the intake air in the collector 3 is introduced from the inlet 8a of the second port 8, The operation is performed in a state where the gas passes through the first port 7 and is guided to the cylinder. In this operating state, the length of the effective intake port is the total passage length L3 from the inlet 8a of the second port 8 to the intake valve of the engine, that is, the total passage length L3 of the first port 7 and the second port 8, and In addition, an intake inertia effect is obtained in a low-to-medium rotation range, and the intake efficiency is improved, and a high torque is obtained.
[0016]
Further, the passage length L2 of the second port 8 is formed to be 25 to 50% of the total passage length L3 of the first port 7 and the second port 8 (that is, 0.25 ≦ (L2 / L3) ≦ 0. .50). The reason will be described with reference to FIGS.
[0017]
FIG. 2 is a diagram illustrating torque characteristics when a switching operation is performed by the variable intake valve, wherein the horizontal axis indicates the engine speed and the vertical axis indicates the shaft torque. Then, the operation of closing the variable intake valve in the low engine speed region of FIG. 2 and performing intake from the inlet of the long port (total passage length L3) is indicated by TL in the figure, and the variable intake valve 9 is opened in the high engine speed region. The operation of performing suction from the inlet of the short port (first port) is indicated by TH in the figure.
[0018]
FIG. 3 is an experimental result showing the relationship between the ratio of the second port length L2 to the total passage length L3 (L2 / L3 (%)) and the inertial supercharging point engine speed by the apparatus of the present invention ( The passage cross-sectional area ratio B / A is 50%). This figure shows an operation state in which the variable intake valve 9 is closed and air is taken from the inlet 8a of the second port 8.
[0019]
If the ratio of the second port L2 to the total passage length L3 exceeds 50% (that is, (L2 / L3)> 0.50), referring to FIG. 2, the inertia tuning point in the low engine speed range and the high engine speed range The width W with respect to the inertia tuning point becomes too large, and the torque step (illustrated h) becomes large when shifting from low speed to high speed. And, since the intake resistance at low speed becomes too large, it is desirable that this ratio is 50% or less (that is, (L2 / L3) ≦ 0.50).
[0020]
However, as shown in FIG. 3, when the ratio of the second port L2 to the total passage length L3 is less than 25% (that is, (L2 / L3) <0.25), the target rotational speed will obtain the inertia effect. (H in the figure becomes large), and a sufficient inertia effect cannot be obtained, resulting in a decrease in engine output performance. Therefore, this ratio is 25% or more. It is desirable (that is, 0.25 ≦ (L2 / L3)).
[0021]
The tuning rotation of the inertia effect has the following relationship.
Synchronous rotation speed ∝ 断面 (port cross-sectional area of port / port length)
For this reason, synchronous rotation of the inertia effect is achieved depending on the relationship between the passage cross-sectional area of the port and the port length. As described above, in the low engine speed range, the variable intake valve 9 is closed, and the port length is switched to be longer, and the second port is switched. When the operation is performed by the intake from the inlet portion 8a of the engine 8, the synchronous rotation of the inertia effect can be adjusted to the low engine rotation speed side. On the other hand, in the high engine speed range, when the variable intake valve 9 is opened and the port length is switched to be short, and the operation is performed by the intake from the inlet portion 7a of the first port 7, the tuning speed of the inertia effect is reduced to the high engine speed side. Can be adjusted to
[0022]
The ratio of the length L2 of the second port 8 to the total passage length L3 is in the range of 25% to 50% as described above, and accordingly, the inertia effect is tuned even in the low engine speed range and the high engine speed range. The size of the passage cross-sectional area A of the first port 7 and the passage cross-sectional area B of the second port 8 are appropriately determined (for example, the passage cross-sectional area B with respect to the passage cross-sectional area A is 50 to 80%).
[0023]
Here, FIG. 4 is a diagram showing the torque characteristics of the device of the present invention and the conventional device, in which the horizontal axis shows the engine speed and the vertical axis shows the shaft torque. The torque characteristic of the device of the present invention is shown by a solid line, and the torque characteristic of the conventional device is shown by a broken line.
[0024]
In the device of the present invention, the passage sectional area A of the first port 7 is smaller than the passage sectional area B of the second port 8, and the ratio of the passage length L2 of the second port 8 to the total passage length L3 is 25 to 50%. 4 (see FIGS. 1 to 3), the inertia effect is tuned in the low engine speed range and the high engine speed range, and the variable intake valve 9 is switched, as shown in FIG. Thus, the output performance can be improved in both the low engine speed range and the high engine speed range.
[0025]
According to the present embodiment, the passage cross-sectional area B of the second port 8 is formed smaller than the passage cross-sectional area A of the first port 7. For this reason, by switching the variable intake valve 9, it is possible to properly tune the inertia effect in the low engine speed range and the high engine speed range. That is, in the high rotation range, the variable intake valve 9 is opened, and the operation is performed by the intake from the first port 7 having a large passage cross-sectional area, thereby reducing the pressure loss of the first port 7 and reducing the output performance. Can be prevented. On the other hand, in the low rotation speed range, the variable intake valve 9 is closed, the length of the long port (the total passage length of the first port and the second port) is secured, and the second port 8 having the small passage cross-sectional area is opened. By performing the operation using the intake air, the inertia effect can be synchronized. Further, even when the engine room layout is severely restricted, the passage length L2 of the second port 8 can be secured.
[0026]
According to the present embodiment, the passage length L2 of the second port 8 is 25 to 50% of the total passage length L3 of the first port 7 and the second port 8. For this reason, when the second port 8 is too long with respect to the total passage length L3, the width W (see FIG. 2) of the inertia tuning point in the low engine speed range and the inertia tuning point in the high engine speed range becomes too large, and the low It is possible to prevent the occurrence of a torque step when shifting from rotation to high rotation, and to prevent the intake resistance during low rotation from becoming excessive. On the other hand, when the length L2 of the second port 8 is too short with respect to the total passage length L3, it is possible to prevent a sudden departure from the target rotational speed for obtaining the inertial effect (see FIG. 3).
[0027]
Further, according to the present embodiment, the first port 7 and the second port 8 communicate with the collector 3 at the inlet 7a of the first port 7 and the inlet 8a of the second port 8, which are the connecting portions. The variable intake valve 9 is an opening / closing valve that opens and closes a communication part between the inlet 7 a of the first port 7 and the collector 3. Therefore, by opening and closing the variable intake valve 9, it is possible to switch between the intake from the inlet 7 a of the first port 7 and the intake from the inlet 8 a of the second port 8.
[0028]
Next, a second embodiment will be described.
5A and 5B show an intake manifold 2 provided with a variable intake device 1 for an internal combustion engine according to a second embodiment, wherein FIG. 5A is a cross-sectional view, and FIG. 5B is a line X in a state where the valve element of the variable intake valve is operated. FIG. Note that parts corresponding to the same parts as in the first embodiment are denoted by the same reference numerals or symbols.
[0029]
In the intake manifold 2, the cross section of the intake pipe 4 through which intake air from the collector 3 flows into each cylinder is formed in a substantially rectangular shape (see FIG. 5B), and a part of the passage wall in the circumferential direction is a variable intake valve 11. It consists of a valve element. The variable intake valve 11 uses a swing valve that can perform a projecting / retreating operation by swinging (swinging) the valve body.
[0030]
The swing valve 11 is formed in a plate shape, and its tip end (collector 3 side) is bent in a direction opposite to the direction in which the valve 11 enters, and the cross-sectional area and the passage of the second port 8 depend on the swing amount. Change the length. One end of the valve 11 on the cylinder side is fixed to the rotating shaft 10, and the rotation of the shaft 10 allows the tip plate portion 11 a of the swing valve 11 to continuously protrude and retreat from the position indicated by α to the position indicated by γ. . The drawing shows a case where the plate portion 11a is at the position β (neutral position) in the drawing.
[0031]
When the tip plate 11a is at the position indicated by α in the drawing due to the retreating operation of the swing valve 11, the second port 8 is substantially eliminated. The sectional area of the intake passage (intake pipe 4) at this time is the same as the sectional area C of the first port 7 as shown in FIG.
[0032]
When the tip plate portion 11a continuously protrudes from the position indicated by α to the position indicated by γ by the projecting operation of the swing valve 11, the passage cross-sectional area and the passage length of the second port 8 are changed according to the position of the plate portion 11a. Change.
[0033]
When the tip plate portion 11a of the swing valve 11 is at the position of γ in the figure, the second port 8 is constituted by the tip plate portion 11a. At this time, the length L2 in the passage direction from the tip of the tip plate portion 11a on the collector 3 side to the rotary shaft 10 is the length of the second port 8. As shown in FIG. 5B, the cross-sectional area of the intake passage at this time is the cross-sectional area D of the second port 8 and the cross-sectional area C of the first port 7.
[0034]
FIG. 6 is a diagram illustrating torque characteristics of the device according to the present embodiment and the conventional device. The horizontal axis indicates the engine speed, and the vertical axis indicates the shaft torque.
Since the length L2 of the second port 8 and the cross-sectional area D of the passage are continuously changed by changing the swing amount of the swing valve 11 by the rotation of the rotating shaft 10, as shown in FIG. In any of the regions, the output performance is improved.
[0035]
According to the present embodiment, the second port 8 is configured such that a part of the passage wall in the circumferential direction is constituted by the swing valve 11, and the swing valve 11 protrudes to form the passage wall of the second port 8 (FIG. 5 (a), the second port 8 is substantially eliminated by the retreat operation (see, α in FIG. 5 (a)). Therefore, by continuously changing the position of the tip plate portion 11a of the swing valve 11 according to the engine rotation range and continuously changing the length L2 of the second port 8 and the passage cross-sectional area D, Optimal inertia and pulsation effects can be obtained in each rotation range, and smoother output characteristics can be obtained.
[0036]
Further, in the present embodiment, the variable intake valve 9 is configured such that the valve body constituting the passage wall of the second port 8 swings around an axis provided on the downstream side of the second port 8 so that the distal end portion is the second port 8. 8 is a swing valve 11 that protrudes and retreats on the upstream side of the valve 8. This valve 11 has a plate-like shape, the tip of which is bent in the direction opposite to the protruding direction. And the path length. For this reason, the swing amount of the swing valve 11 is determined by the rotating shaft 10, and the passage length L 2 and the passage cross-sectional area D of the second port 8 according to the engine rotation range are determined by the position of the tip plate portion 11 a of the swing valve 11. By doing so, it is possible to obtain an optimal inertial effect and a pulsating effect, and it is possible to obtain smoother output characteristics.
[0037]
Next, a third embodiment will be described.
7A and 7B show an intake manifold 2 provided with a variable intake device 1 for an internal combustion engine according to a third embodiment, wherein FIG. 7A is a cross-sectional view, and FIG. 7B is a line X in a state where the valve element of the variable intake valve is moved. FIG.
[0038]
In the intake manifold 2, a lower portion of a passage wall of an intake passage (intake pipe 4) is configured by a valve body of a variable intake valve 12. The variable intake valve 12 uses a slide valve that allows the valve body to enter and exit. By sliding the slide valve 12, it is possible to continuously protrude and retreat from the position indicated by α ′ to the position indicated by γ ′.
[0039]
The slide valve 12 is a valve body that constitutes or substantially eliminates the passage wall of the second port 8 and moves obliquely toward the upstream side with respect to a direction perpendicular to the virtual axis of the second port 8.
[0040]
When the slide valve 12 is at the position α ′ in the drawing due to the retreat operation, the second port 8 is substantially eliminated.
When the slide valve 12 continuously protrudes from the position α ′ to the position γ ′ in the drawing, the passage cross-sectional area D ′ and the passage length L2 of the second port 8 change according to the amount of movement. .
[0041]
When the slide valve 12 is at the position γ ′ in the figure, the length L2 from the tip of the valve 12 (collector 3 side) to the inlet of the first port 7 is the length of the second port 8.
[0042]
FIG. 6 showing the torque characteristics of the device according to the present embodiment and the conventional device is the same as that of the second embodiment. In this case, the slide valve 12 is moved to tune the inertia effect appropriately. Thus, it is possible to prevent a decrease in output performance in a wide engine rotation range.
[0043]
According to the present embodiment, the variable intake valve is a slide in which the valve body forming the passage wall of the second port 8 moves obliquely toward the upstream side with respect to a direction perpendicular to the virtual axis of the second port 8. The valve 12 changes a passage cross-sectional area and a passage length of the second port 8 according to a movement amount. For this reason, when the second port 8 substantially disappears due to the movement amount (position) of the slide valve 12 and the intake by the first port 7 is performed (see α ′ in FIG. 7A), the second The switching can be performed when the length L2 of the port 8 and the cross-sectional area D ′ of the passage change (see γ ′ in FIG. 7A). Further, output performance can be ensured in a wide rotation range from the low rotation range to the high rotation range of the engine. Then, by continuously changing the slide position by the slide valve 12, the passage cross-sectional area and the port length can be changed, and the optimum inertia effect and pulsation effect can be obtained in each engine rotation range, and the smoothness can be obtained. Output characteristics can be obtained.
[0044]
Although the slide valve 12 is inclined toward the upstream side with respect to the direction perpendicular to the virtual axis of the second port 8, the slide valve 12 is directed toward the direction perpendicular to the virtual axis, that is, the flow path of the intake passage 4. Alternatively, only the cross-sectional area C ′ of the passage may be changed by sliding in the direction perpendicular to the direction.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an intake manifold including a variable intake device of an internal combustion engine according to a first embodiment; FIG. 2 is a torque characteristic diagram when a switching operation is performed by a variable intake valve; FIG. FIG. 4 is a diagram showing the relationship between the ratio of the port length and the rotational speed of the inertia supercharging point engine. FIG. 4 is a diagram showing the torque characteristics of the present invention and the conventional device. FIG. 6 is a cross-sectional view of an intake manifold provided. FIG. 6 is a torque characteristic diagram of an apparatus according to a second embodiment and a conventional apparatus. FIG. [Explanation of symbols]
REFERENCE SIGNS LIST 1 Variable intake device of internal combustion engine 2 Intake manifold 3 Collector 4 Intake pipe 5 Outlet flange 7 First port 7a Inlet 8 Second port 8a Inlet 9 Variable intake valve 10 Rotary shaft 11 Swing valve 11a Tip plate 12 Slide valve

Claims (6)

An intake passage for distributing intake air in the collector of the intake manifold to each cylinder is connected to a short port constituted by a first port by a variable intake valve and a second port connected in series upstream of the first port. In a variable intake device for an internal combustion engine switchable to a long port constituted by a first port and a second port,
A variable intake device for an internal combustion engine, wherein a cross-sectional area of a passage of the second port is smaller than a cross-sectional area of a passage of the first port. The variable intake device for an internal combustion engine according to claim 1, wherein a passage length of the second port is 25 to 50% of a total passage length of the first port and the second port. The first port and the second port are configured to communicate with the collector at an inlet of the first port and an inlet of the second port, which are connecting portions thereof.
3. The variable intake device for an internal combustion engine according to claim 1, wherein the variable intake valve is an opening / closing valve that opens and closes a communication portion between an inlet of the first port and the collector. The second port has a structure in which a part of the passage wall in a circumferential direction is configured by a valve body of the variable intake valve.
2. The variable intake valve according to claim 1, wherein the valve body constitutes a passage wall of the second port by a projecting operation of the valve body, and the second port is substantially eliminated by a retreat operation. A variable intake device for an internal combustion engine according to claim 2. In the variable intake valve, a valve body constituting a passage wall of the second port swings around an axis provided on a downstream side of the second port so that a distal end portion protrudes into an upstream side of the second port. A reversing swing valve, wherein the valve element is plate-shaped, and the distal end side is bent to the opposite side to the rush direction, and the cross-sectional area and the path length of the second port change depending on the swing amount. The variable intake device for an internal combustion engine according to claim 4, wherein: The variable intake valve is a slide valve in which a valve body forming a passage wall of the second port moves obliquely toward an upstream side with respect to a direction perpendicular to an imaginary axis line of the second port. 5. The variable intake device for an internal combustion engine according to claim 4, wherein a passage cross-sectional area and a passage length of the second port change according to the condition.

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