JP2004293513A - Air intake device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air intake device for an engine capable of offering a good controllability for opening and closing the communication passage to a sub-tank without hindering the intake flow. <P>SOLUTION: The air intake device of the engine is composed of an intake passage 11 connected with a cylinder of the engine, a surge tank 14 installed in the intake passage, the sub-tank 20 installed between the surge tank and the cylinder through the communication passage, a butterfly valve 22 having a peripheral shape to suit the inside shape of the communication passage and opening and closing the communication passage through a turning shaft 23, and an actuator 24 installed facing the communication passage and actuating the turning shaft, wherein the turning shaft is positioned offset e from the center O of the valve width in the direction perpendicular to the turning shaft of the butterfly valve and passing the valve center G as shown in Fig. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an intake device for an engine, and more particularly, to an intake device for an engine for improving engine output by an intake inertia effect.
[0002]
[Prior art]
As an intake device for an engine, a configuration in which a sub tank is provided between a surge tank and a cylinder is known. With this configuration, the amount of intake air and the volumetric efficiency are increased by utilizing the inertia and the pulsation effect of the intake air.
Specifically, in view of the fact that the negative pressure wave generated by the start of intake propagates to either the surge tank or the sub tank, is reflected at the open end of either of them, and returns to the cylinder side again as a positive pressure wave, The timing of returning to the intake side is synchronized with the approximate closing timing of the intake valve, and the intake air is pushed in with the next opening of the intake valve. Things.
[0003]
FIG. 3 is an enlarged view of the vicinity of a communication passage in a conventional engine intake device utilizing the intake inertia effect.
As shown in FIG. 2A, the sub tank 120 is provided in the intake passage 111 via the communication passage 121, and an actuator 124 is provided on the outer peripheral side of the communication passage 121. The actuator 124 operates a rotation shaft 123 disposed at a center position of the length of the communication path 121 and at the center O of the communication path 121.
[0004]
The rotary shaft 123 passes through the center O of the circular butterfly valve 122, as shown in FIG. 2B when the butterfly valve 122 is viewed from the intake passage 111 side, and is connected by the butterfly valve 122. The passage 121 is opened and closed.
Then, in the low-to-medium speed region of the engine speed, the butterfly valve 122 is closed to disconnect the sub tank 120, and the surge tank 114 is used as an open end to reflect the negative pressure wave of the intake air. On the other hand, in a high engine speed range, the butterfly valve 122 is opened to reflect the negative pressure wave of the intake air with the sub-tank 120 as an open end. By utilizing such an intake inertia effect, the torque can be improved over the entire operation range.
[0005]
Here, since the size of the intake device of the engine having the sub-tank is limited in terms of mounting in an engine room, a technique of an engine intake device for solving this problem has been proposed (for example, see Patent Reference 1).
In this device, a configuration such as a sub tank adjacent to the surge tank is used, and the intake device of the engine is made compact.
[0006]
Further, various similar technologies have been proposed for the intake device of the engine (for example, see Patent Documents 2 and 3).
[0007]
[Patent Document 1]
JP-A-9-264143 (paragraphs 0006, 0013 to 0020, 0025, FIG. 4, FIG. 8, etc.)
[Patent Document 2]
Japanese Utility Model Publication No. 2-47235 (Figs. 1 and 2)
[Patent Document 3]
Japanese Utility Model No. 2507971 (Fig. 1 etc.)
[0008]
[Problems to be solved by the invention]
By the way, in the intake device of the engine, as shown in FIG. 3A, the rotating shaft 123 is disposed at the center of the length of the communication passage 121. This is because the length of the communication passage 121 is limited based on the relationship between the distance from the cylinder to the surge tank 114 and the distance from the cylinder to the sub tank 120 in order to reflect the negative pressure wave, and the engine room This is because there is a limitation based on the mounting on the actuator, and the installation position of the actuator 124 for operating the rotation shaft 123 is recognized only within a range corresponding to the length of the communication path 121.
[0009]
Here, when the butterfly valve 122 is opened, when the butterfly valve 122 is fully opened, the tip end portion 122R of the butterfly valve 122 may protrude toward the intake passage 111. A problem arises that the flow is hindered and the intake inertia effect cannot be fully utilized.
In this case, it is difficult to move the rotation shaft 123 toward the sub tank 120 because the allowable range of the installation position of the actuator 124 is narrow.
[0010]
On the other hand, if the rotating shaft passes through the end of the butterfly valve without passing through the center of the butterfly valve as in the embodiment shown in the above-mentioned prior art, the tip of the butterfly valve faces the intake passage. And the intake air flow is not hindered.
However, when the butterfly valve is rotated with reference to the end thereof, since a pressure due to intake air is always generated in the butterfly valve, a large moment is generated in the butterfly valve as it moves away from the rotation axis, and in particular, the butterfly valve Is moved between the fully opened position and the fully closed position, the moment becomes extremely large, and the controllability of opening and closing the communication path is deteriorated.
[0011]
The present invention has been made in view of such a problem, and it is an object of the present invention to provide an intake device for an engine that can improve controllability of opening and closing a communication passage to a sub-tank without obstructing intake air flow. Aim.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an intake device for an engine according to claim 1 includes an intake passage connected to a cylinder of the engine, a surge tank provided in the intake passage, and a communication passage between the surge tank and the cylinder. And a butterfly valve having an outer peripheral shape adapted to the inner peripheral shape of the communication passage, and opening and closing the communication passage via a rotation shaft, and a sub-tank provided in accordance with the communication passage, An actuator for operating the shaft, the rotating shaft is disposed at a position offset from the center of the valve width in a direction orthogonal to the rotating axis of the butterfly valve, and passes through the centroid of the butterfly valve. Features.
[0013]
Therefore, according to the engine intake device of the first aspect, the rotary shaft is disposed at a position offset from the center of the valve width of the butterfly valve in a direction orthogonal to the rotary shaft. Are not projected to the intake flow side of the intake passage, and the intake flow is not hindered.
In addition, since the rotation axis passes through the center of the butterfly valve, even if pressure due to suction is always applied to the butterfly valve, the moment generated at the one end side of the butterfly valve from the rotation axis and the rotation axis Since the moment generated at the other end side portion of the butterfly valve is canceled, the load on the actuator is reduced, and the controllability of opening and closing the communication passage can be improved.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown a system configuration diagram to which an engine intake device according to an embodiment of the present invention is applied. Hereinafter, a configuration of an engine intake device according to the present invention will be described with reference to FIG.
[0015]
The engine 1 is a multi-cylinder engine, and is configured as a spark ignition type in-cylinder injection engine that directly injects fuel into a combustion chamber (not shown). That is, an injector and a spark plug (both not shown) are provided for each cylinder in the cylinder head of the engine 1 facing the combustion chamber defined by the reciprocating motion of the piston. The passage 31 is connected. The ignition plug is connected to an ignition coil.
[0016]
An air cleaner 12 and a throttle valve 13 are disposed in the intake passage 11 in this order from the upstream side, and a surge tank 14 is further provided downstream. As a result, air from the outside passes through the air cleaner 12 and flows into the combustion chamber via the throttle valve 13, the surge tank 14, and the intake passage 11. At this time, the intake air amount is detected by the air flow sensor 15. Further, a throttle position sensor (TPS) 16 is provided, and the TPS 16 detects the opening of the throttle valve 13.
[0017]
The intake passage 11 includes an intake manifold and an intake port, and the intake port is formed in a substantially upright direction in the cylinder head for each cylinder. On the combustion chamber side of the intake port, there is provided an intake valve 17 that communicates and shuts off the intake port and the combustion chamber. An intake manifold is connected to each cylinder upstream of the intake port, and a sub-tank 20 is provided between the surge tank 14 and the cylinder.
[0018]
The sub-tank 20 is provided in the intake manifold via a communication passage 21, and is configured to communicate with each of the cylinders. The communication passage 21 is provided with a butterfly valve 22 that opens and closes via a rotation shaft 23 disposed at the center of the length of the communication passage 21, and a rotation shaft 23 is provided on the outer peripheral side of the communication passage 21. An actuating actuator 24 is provided.
[0019]
The exhaust passage 31 includes an exhaust port and an exhaust manifold. The exhaust port is formed in a substantially horizontal direction in a cylinder head for each cylinder. An exhaust valve 32 is provided on the combustion chamber side of the exhaust port for communicating and shutting off the exhaust port and the combustion chamber.
An ECU (electronic control unit) 30 including an input / output device, a memory (ROM, RAM, nonvolatile RAM, and the like), a CPU, and the like is provided. The ECU 30 controls the engine 1 comprehensively.
[0020]
The input side of the ECU 30 is connected to various sensors such as a crank angle sensor 33 for detecting an engine rotation speed based on a crank angle signal, in addition to the above-described air flow sensor 15 and TPS 16, and detection information from these sensors. Is entered. Then, the operating state of the engine 1 is obtained from the outputs of these sensors, and the main operation amounts of the engine 1 such as the intake air amount, the fuel injection amount, the fuel injection timing, and the ignition timing are optimally calculated.
[0021]
On the other hand, on the output side of the ECU 30, various output devices such as an actuator 24 for opening and closing the butterfly valve 22 are connected in addition to the above-described injector and spark plug, and the fuel injection amount calculated in the ECU 30 is opened. The pulse signal is converted to a pulse signal and sent to the injector. An ignition plug drive signal is sent to the ignition coil based on the calculated ignition timing, and a drive signal based on the calculated opening is sent to the actuator 24.
[0022]
The fuel injected from the injector is mixed with the conditioned air from the intake passage 11 to form an air-fuel mixture in the combustion chamber. The air-fuel mixture is generated by a spark generated from a spark plug at a predetermined ignition timing. And the combustion pressure drives the engine 1. Exhaust gas after the explosion is sent to an exhaust purification catalytic converter (not shown) through an exhaust passage 31.
[0023]
FIG. 2 is an enlarged view of the vicinity of a communication passage in the intake device of the engine.
As described above, in the intake device of the engine of the present embodiment, the sub-tank 20 is provided in the intake passage 11 between the surge tank 14 and the cylinder via the communication passage 21. In order to reflect the negative pressure wave of the intake air, it is determined based on a comparison between the distance from the cylinder to the surge tank 14 and the distance from the cylinder to the sub-tank 20.
[0024]
The communication path 21 has a predetermined length in the installation direction of the sub-tank 20, as shown in FIG. 3A, and is formed using a mold. The length of the communication passage 21 is also determined in consideration of the mounting in the engine room and the installation position of the sub tank 20.
The communication passage 21 has a rotating shaft 23 arranged at the center of the length of the communication passage 21 and an outer peripheral shape adapted to the inner peripheral shape of the communicating passage 21. A butterfly valve 22 for opening and closing the communication passage 21 is provided.
[0025]
In the present embodiment, for example, in the present embodiment, the rotary shaft 23 is moved toward the actuator 24 side along the flow direction of the intake air from the surge tank 14 at the center position of the length of the communication passage 21. Of the valve width in a direction orthogonal to the rotation shaft 23 of the first rotation axis.
The butterfly valve 22 has a side portion (one end side portion) 22R facing the actuator 24 side as shown in FIG. 2B as viewed from the intake passage 11 side in addition to FIG. It has a triangular shape having a vertex portion (the other end side portion) 22L opposed to the one end side portion 22R with the rotating shaft 23 interposed therebetween, and the position of the centroid G of the triangle is set to the offset position described above. To this end, the amount of eccentricity e from the center O of the communication passage 21 is determined.
[0026]
That is, since the rotating shaft 23 passes through the triangular centroid G, which is the outer shape of the butterfly valve 22, the first moment of area of the butterfly valve 22 with respect to the rotating shaft 23 is made zero.
When the actuator 24 is actuated based on the output signal from the ECU 30 to which the detection signal of the crank angle sensor 33 is inputted, the butterfly valve 22 moves the other end side portion 22L around the rotation shaft 23 to the sub tank. 20 between the fully open position toward the side 20 and the fully closed position in which the one end side portion 22R and the other end side portion 22L are arranged in parallel with the intake air flow direction. Open and close. Note that the inner peripheral shape of the communication passage 21 also has a triangular shape in which one side of the communication passage 21 is opposed at the installation position of the actuator 24.
[0027]
Next, the operation of the intake device for the engine of the present embodiment will be described.
The intake device of the engine closes the butterfly valve 22 to the fully closed position as shown by the solid line in FIG. 11 and the sub tank 20 are not communicated with each other, and the surge tank 14 is set to the open end to increase the length of the pipeline. The negative pressure wave generated by the opening of the intake valve 17 propagates to the surge tank 14 and reflects the negative pressure wave as a positive pressure wave toward the cylinder. By synchronizing the timing at which the wave due to the reflection returns to the cylinder side again with the substantially closing timing of the intake valve 17, the intake air is pushed into the combustion chamber with the next opening of the intake valve 17.
[0028]
On the other hand, in the high engine speed range, the butterfly valve 22 is opened to the fully opened position as indicated by the dotted line in FIG. I do. Then, the negative pressure wave generated by the opening of the intake valve 17 does not propagate to the surge tank 14 but propagates to the sub-tank 20, and reflects the negative pressure wave as a positive pressure wave to the cylinder side. By synchronizing the timing at which the wave due to the reflection returns to the cylinder side again with the substantially closing timing of the intake valve 17, the intake air is pushed into the combustion chamber with the next opening of the intake valve 17.
[0029]
As described above, in the present invention, the butterfly valve 22 has a triangular shape including the one end side portion 22R facing the actuator 24 side and the other end side portion 22L facing the one end side portion 22R with the rotation shaft 23 interposed therebetween. And the rotary shaft 23 is disposed at a position offset from the center O of the valve width in the direction orthogonal to the rotary shaft 23 of the butterfly valve 22 by an eccentric amount e toward the actuator 24 side. When the valve 22 is fully opened, the other end side portion 22 </ b> L is turned toward the sub tank 20.
[0030]
Therefore, even when the butterfly valve 22 is fully opened, the one end edge portion 22R having a shorter distance from the rotating shaft 23 to the edge portion than the other end edge portion 22L protrudes toward the intake flow side of the intake passage 11. As in the present embodiment, the allowable range of the installation position is narrow due to the restriction of the length of the communication path 21, and the configuration of the existing actuator and the configuration of the communication path having a drive shaft to the rotating shaft 23 in the center portion are provided. Thus, the problem of obstructing the flow of intake air from the surge tank 14 in the related art can be solved.
[0031]
Further, since the rotating shaft 23 is configured to pass through the centroid G of the butterfly valve 22, pressure due to the intake air flow is always generated in the butterfly valve 22, and particularly, the opening degree when the butterfly valve 22 is fully opened and the opening degree when the butterfly valve 22 is fully opened. Also when moving between the opening degree at the time of closing, the moment generated at the one end edge side portion 22R and the moment at the other end edge side portion 22L can be offset, and the load on the actuator can be reduced to open and close the communication passage 21. Controllability can be improved.
[0032]
Therefore, according to the above-described engine intake device, the configuration for offsetting the rotary shaft 23 and the configuration for passing the rotary shaft 23 through the centroid G of the butterfly valve 22 combine to maximize the intake inertia effect. , And the torque can be appropriately improved in the entire operation range from low speed to high speed.
The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.
[0033]
For example, in the above embodiment, the butterfly valve 22 has a triangular shape, but is not necessarily limited to this shape. For example, a configuration in which the rotation axis is offset and the center of the butterfly valve passes through The shape may be a trapezoidal shape or a fan shape, and the same effect as in the above embodiment can be obtained by adjusting the inner peripheral shape of the communication passage to the outer peripheral shape of the butterfly valve.
[0034]
The eccentricity e is also arranged at a position offset by the eccentricity e from the center O of the valve width in the direction orthogonal to the rotation axis 23 of the butterfly valve 22 along the direction of intake air flow from the surge tank 14. In this case, the butterfly valve 22 is arranged toward the actuator 24 from the center O of the valve width in the direction orthogonal to the rotation axis 23 of the butterfly valve 22 as in the above embodiment, and is arranged in a direction away from the actuator 24. May be performed. In this case, in the butterfly valve, the longer distance from the rotation shaft to the edge portion is set to the opening degree when fully opened toward the sub-tank side, but also in this case, similarly to the above-described embodiment. Thus, the effect of improving the controllability of opening and closing the communication passage without obstructing the intake air flow can be achieved. Further, the eccentricity e may be offset in a direction perpendicular to the intake flow, in addition to the case where the eccentric amount e is offset in the direction along the intake flow as in the above-described embodiment. The axis is arranged in a direction along the intake flow.
[0035]
【The invention's effect】
As can be understood from the above description, according to the engine intake device of the first aspect of the present invention, the rotation axis is offset from the center of the valve width of the butterfly valve in a direction orthogonal to the rotation axis. Since the butterfly valve is disposed at the position, the butterfly valve does not protrude toward the intake flow side of the intake passage, thereby preventing the intake flow from being obstructed.
[0036]
In addition, since the rotation axis passes through the center of the butterfly valve, even if pressure due to intake air is always applied to the butterfly valve, the moment generated from the rotation axis to one end side of the butterfly valve and the rotation axis Since the moment generated at the other end side portion of the butterfly valve is canceled, the load on the actuator is reduced, and the controllability of opening and closing the communication passage can be improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an engine system to which an intake device for an engine according to an embodiment of the present invention is applied.
FIG. 2 is an enlarged view of the vicinity of a communication passage in the intake device of the engine of FIG. 1;
FIG. 3 is an enlarged view of the vicinity of a communication passage in a conventional engine intake device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 11 Intake passage 14 Surge tank 17 Intake valve 20 Subtank 21 Communication passage 22 Butterfly valve 23 Rotating shaft 24 Actuator

Claims (1)

An intake passage connected to the cylinder of the engine,
A surge tank provided in the intake passage;
A sub tank provided between the surge tank and the cylinder via a communication passage;
A butterfly valve having an outer peripheral shape that matches the inner peripheral shape of the communication passage, and opening and closing the communication passage via a rotating shaft;
An actuator that is provided along the communication path and that operates the rotation shaft;
The rotary shaft is arranged at a position offset from a center of a valve width of the butterfly valve in a direction orthogonal to the rotary shaft, and passes through a center of the butterfly valve. apparatus.

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