JP2007056733A - Variable intake system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable intake system for an internal combustion engine capable of improving the efficiency of intake when the internal combustion engine is operated in a low rotational speed zone. <P>SOLUTION: This intake system is provided with a main intake pipe 17 connected with an introduction port of an air cleaner and an auxiliary intake pipe 18 communicated with the introduction port through the main intake pipe 17 and being openable and closable. Cross sectional area of a flow passage of the main intake pipe 17 is equal to cross sectional area of the introduction port of the air cleaner or more. On the other hand, cross sectional area of a flow passage of the auxiliary intake pipe 18 is smaller than cross sectional area of the introduction port. The main intake pipe 17 is composed of a terminal part 17a extending in the direction of opening of the introduction port and a tip part 17b curved at substantially 90° and extending from a tip of the terminal part 17a. The auxiliary intake pipe 18 is extended in the direction of opening of the introduction port of the air cleaner from a peripheral wall on an outer side of a curved part of the main intake pipe 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable intake device that includes a main intake pipe and a sub intake pipe in an internal combustion engine.

  Conventionally, as this type of variable intake device, for example, there is one described in Patent Document 1. In this variable intake device, as shown in FIG. 4, an intake manifold 51, a throttle body 52, and an air cleaner 53 are sequentially connected to an intake port of an engine 50, and an intake pipe 54 is connected to an introduction port of the air cleaner 53. . The intake pipe 54 includes a main intake pipe 55 and a sub intake pipe 56 having an intake passage shorter than the main intake pipe 55. The main intake pipe 55 is an intake pipe for introducing air into the air cleaner 53 in a low rotation range where the engine speed is less than a predetermined value, and the auxiliary intake pipe 56 is a high rotation speed range where the engine speed is a predetermined value or more. The intake pipe is communicated with the air cleaner 53 and introduces more air. An opening / closing valve 57 for opening / closing the auxiliary intake pipe 56 is provided inside the auxiliary intake pipe 56. The open / close valve 57 is driven by an actuator 58 and is closed in a low rotation operation region of the engine 50 where the negative pressure in the intake manifold 51 is low, thereby blocking the communication of the auxiliary intake pipe 56 with the air cleaner 53. The auxiliary intake pipe 56 is communicated with the air cleaner 53 by being opened in a high rotation operation range where the pressure is high.

As shown in FIG. 5, the main intake pipe 55 and the auxiliary intake pipe 56 are connected to the introduction port 59 of the air cleaner 53 substantially in parallel. That is, the intake air flow path entering the air cleaner 53 from the main intake pipe 55 and the intake air flow path entering the air cleaner 53 from the auxiliary intake pipe 56 are substantially separated.
Japanese Patent Application Laid-Open No. 2004-44528 (page 4, FIG. 2)

  In the variable intake device disclosed in Patent Document 1, the main intake pipe 55 and the sub intake pipe 56 are connected in parallel to the introduction port 59 having a limited cross-sectional area corresponding to a predetermined cleaner volume. The cross-sectional area of the main intake pipe 55 is smaller than the cross-sectional area of the introduction port 59. For this reason, the ventilation resistance of the intake device in the low rotation range where intake is performed only from the main intake pipe 55 is higher than that of the intake apparatus that does not perform variable intake that has only one intake pipe. . For this reason, the intake efficiency at the time of driving | running | working in the low rotation area of an engine could not fully be improved.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a variable intake device for an internal combustion engine that can improve intake efficiency when the internal combustion engine is operated in a low-rotation operation region.

  In order to achieve the above object, an invention according to claim 1 is directed to an internal combustion engine including a main intake pipe connected to an inlet of an air cleaner, and an auxiliary intake pipe connected to the inlet and openable / closable. In the engine intake device, the cross-sectional area of the flow path of the main intake pipe is equal to or greater than the cross-sectional area of the inlet of the air cleaner, and the auxiliary intake pipe is communicated with the inlet through the main intake pipe. It is characterized by that.

The invention according to claim 2 is characterized in that, in addition to the invention according to claim 1, the auxiliary intake pipe extends in the opening direction of the inlet of the air cleaner.
According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, an opening / closing valve for blocking communication of the auxiliary intake pipe with the air cleaner is provided inside the auxiliary intake pipe. The opening / closing valve can be accommodated in a recess provided inside the peripheral wall on the opposite side of the main intake pipe inside the auxiliary intake pipe, and disposed on the proximal end side of the auxiliary intake pipe in the recess. It is characterized in that it is rotatably supported by the supported spindle.

  According to a fourth aspect of the present invention, in addition to the third aspect of the present invention, the on-off valve has a cross-sectional shape of a flow path of the main intake pipe through the connection opening of the auxiliary intake pipe in the main intake pipe. By blocking so as not to change, the communication between the auxiliary intake pipe and the main intake pipe is blocked.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the main intake pipe extends in the opening direction of the inlet of the air cleaner and then the direction of the flow path. The auxiliary intake pipe is extended from the peripheral wall outside the curved portion of the main intake pipe in the opening direction of the introduction port.

  According to this invention, the cross-sectional area of the flow path of the main intake pipe is equal to or greater than the cross-sectional area of the air cleaner inlet, and the auxiliary intake pipe communicates with the inlet through the main intake pipe. The flow passage cross-sectional area of the main intake pipe is not limited by the presence of the auxiliary intake pipe. For this reason, in the low rotation operation range of the internal combustion engine that performs intake by the main intake pipe, it is possible to reduce the ventilation resistance of the variable supply device and improve the intake efficiency.

  Moreover, it is preferable to extend the auxiliary intake pipe in the opening direction of the inlet of the air cleaner. In this case, since the ventilation resistance in the auxiliary intake pipe is reduced, it is possible to improve the intake efficiency by reducing the ventilation resistance of the variable intake device in the high speed operation range of the internal combustion engine that performs intake by the auxiliary intake pipe. it can.

  Further, an open / close switching valve is rotatably supported at one end of the auxiliary intake pipe, and the open / close valve is disposed at a closed position forming a part of the peripheral wall of the main intake pipe. It is preferable to do so. In this case, since the flow passage of the auxiliary intake pipe does not open in the peripheral wall of the main intake pipe during intake from the main intake pipe, the ventilation resistance in the main intake pipe is reduced, and the intake efficiency in the low-rotation operation region is further improved. To do.

  Further, it is preferable that a recess is formed in the peripheral wall of the auxiliary intake pipe so that the opening / closing valve disposed at the open position can be accommodated in the recess. In this case, since the opening / closing valve does not become an obstacle to intake during intake from the auxiliary intake pipe, it is difficult for the ventilation resistance to increase, and the intake efficiency in the high rotation operation range is further improved.

  Further, the main intake pipe is bent so as to change the direction of the flow path after extending in the opening direction of the inlet of the air cleaner, and the auxiliary intake pipe is bent from the peripheral wall outside the curved portion of the main intake pipe. It is preferable to extend in the opening direction. In this case, the auxiliary intake pipe is connected to form a more obtuse angle with respect to the main intake pipe, and the opening area of the auxiliary intake pipe in the peripheral wall of the main intake pipe is reduced. The opening / closing valve can be reduced in size compared to the case where it is connected to a part other than the part.

Next, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 2, an intake manifold 11 is connected to an intake port of a gasoline engine (hereinafter simply referred to as an engine) 10 as an internal combustion engine, and the intake manifold 11 is provided with a throttle body 12 in the middle. It is connected to an air cleaner 14 through an intake extension pipe 13. The intake device 16 of this embodiment is connected to the inlet 15 of the air cleaner 14.

  As shown in FIGS. 1A and 1B, the intake device 16 includes a main intake pipe 17 connected to the inlet 15 of the air cleaner 14, and a sub intake pipe 18 connected to the main intake pipe 17. It has. The main intake pipe 17 has a base end portion 17a extending in the opening direction of the introduction port 15, and a front end portion 17b extending by bending approximately 90 ° from the front end side of the base end portion 17a so as to change the direction of the flow path. Consists of. The auxiliary intake pipe 18 extends from the peripheral wall outside the curved portion of the main intake pipe 17 in the opening direction of the introduction port 15. That is, the auxiliary intake pipe 18 communicates with the inlet 15 of the air cleaner 14 via the main intake pipe 17.

  As shown in FIG. 3A, the cross-sectional area in a plane orthogonal to the extension direction of the flow path of the main intake pipe 17 (that is, the cross-sectional area of the flow path) is substantially equal to the cross-sectional area of the inlet 15 having a substantially rectangular shape. It is said that. On the other hand, the cross-sectional area of the flow path of the auxiliary intake pipe 18 is made smaller than the cross-sectional area of the inlet 15.

  As shown in FIGS. 1A and 1B, a recess 19 is provided on the inner side of the auxiliary intake pipe 18 on the side opposite to the main intake pipe 17, and the auxiliary intake pipe 18 is provided in the recess 19. An opening / closing valve 20 for opening and closing is rotatably supported by a support shaft 21 at one end thereof. The on-off valve 20 is disposed at a position in the recess 19 and a position protruding outward from the recess 19. As shown in FIG. 1 (b), the opening / closing valve 20 is accommodated in the recess 19 so that it can be disposed at an open position where the flow path of the auxiliary intake pipe 18 is opened. Further, as shown in FIG. 1A, the opening / closing valve 20 closes the flow path of the auxiliary intake pipe 18 and forms a part of the peripheral wall of the main intake pipe 17 by projecting outside the recess 19. It can be placed at the position. The recess 19 and the opening / closing valve 20 are both substantially rectangular.

  Further, a negative pressure actuator 22 is provided outside the bottom wall of the recess 19 in the auxiliary intake pipe 18 for rotating the open / close valve 20 from the closed position to switch to the open position. As shown in FIG. 2, the negative pressure actuator 22 is connected to a negative pressure tank 25 via a three-way switching valve 24, and the negative pressure tank 25 is connected to the intake manifold 11 via a check valve 26. The three-way switching valve 24 bypasses the negative pressure tank 25 and the check valve 26 and is connected to the intake manifold 11. Negative pressure is introduced into the negative pressure tank 25 from the intake manifold 11 via a check valve 26. The three-way switching valve 24 operates in response to an operation signal from the control device 27, and introduces a negative pressure from the negative pressure tank 25 to the negative pressure actuator 22 and releases a negative pressure of the negative pressure actuator 22.

  As shown in FIGS. 1 (a) and 1 (b), the negative pressure actuator 22 includes an operating shaft 23 that passes through the bottom wall of the recess 19 and is connected to the open / close valve 20, and has an internal return spring (not shown). The open / close valve 20 is switched from the open position to the closed position by causing the operating shaft 23 to protrude by force.

  The control device 27 releases the negative pressure of the negative pressure actuator 22 when the engine speed is less than a predetermined speed. Accordingly, the control device 27 arranges the opening / closing valve 20 in the closed position as shown in FIG. 1A when the engine 10 is operating in the low-rotation operation region and when the engine 10 is stopped. The communication of the auxiliary intake pipe 18 to the air cleaner 14 via the intake pipe 17 is blocked. Further, the control device 27 causes the negative pressure actuator 22 to introduce a negative pressure when the engine speed is equal to or higher than a predetermined speed. As a result, the control device 27 arranges the opening / closing valve 20 at the open position and operates the auxiliary intake air via the main intake pipe 17 as shown in FIG. The pipe 18 is communicated with the air cleaner 14.

  In the intake device 16 configured as described above, since no negative pressure is introduced into the negative pressure actuator 22 when the engine 10 is stopped, the open / close valve 20 is held in the closed position by the urging force of the return spring. For this reason, when the engine 10 is stopped, the auxiliary intake pipe 18 is in a closed state, and dust, water, or the like does not enter the engine 10 side through the auxiliary intake pipe 18 from the outside.

  Further, since the negative pressure is not introduced into the negative pressure actuator 22 even when the engine 10 is operated in the low speed operation region, the on-off valve 20 is held in the closed position. Then, air is sucked into the engine 10 through the main intake pipe 17 in the low speed operation region of the engine 10. At this time, since the cross-sectional area of the flow path of the main intake pipe 17 is substantially equal to the cross-sectional area of the inlet 15 of the air cleaner 14, the ventilation resistance of the main intake pipe 17 is reduced as compared with the conventional configuration, and the engine 10 Intake efficiency is improved during operation in the low-speed operation range. In addition, since the opening / closing valve 20 disposed at the closed position forms a part of the peripheral wall of the main intake pipe 17, the flow path of the auxiliary intake pipe 18 on the peripheral wall of the main intake pipe 17 during intake from the main intake pipe 17. Does not open. For this reason, the ventilation resistance in the main intake pipe 17 is reduced, and the intake efficiency in the low rotation operation region is further improved.

  When the engine 10 is operating in the high speed operation region, negative pressure is introduced into the negative pressure actuator 22 by the control device 27, so that the open / close valve 20 is switched from the closed position to the open position by the operation of the negative pressure actuator 22. . Then, air is sucked into the engine 10 through the auxiliary intake pipe 18 in the high speed operation region of the engine 10. At this time, since the auxiliary intake pipe 18 extends in the opening direction of the inlet 15 of the air cleaner 14, the ventilation resistance in the auxiliary intake pipe 18 is reduced, and the air intake efficiency is further improved. Furthermore, since the opening / closing valve 20 disposed in the open position is accommodated in the recess 19 of the auxiliary intake pipe 18 and retracts from the flow path of the auxiliary intake pipe 18, the ventilation resistance in the auxiliary intake pipe 18 hardly increases. For this reason, the intake efficiency in the high speed operation region is further improved.

  Therefore, according to this embodiment, unlike the conventional intake device, the cross-sectional area of the flow path of the main intake pipe 17 is not limited by the presence of the auxiliary intake pipe 18, so that the long intake passage in the low speed operation region of the engine 10 The intake efficiency of the main intake pipe 17 having the above can be improved.

  Further, the main intake pipe 17 is curved after extending in the opening direction of the inlet 15 of the air cleaner 14, and the auxiliary intake pipe 18 is bent from the peripheral wall outside the curved portion of the main intake pipe 17 in the opening direction of the inlet 15. It was extended. For this reason, the auxiliary intake pipe 18 is connected to form a more obtuse angle with respect to the main intake pipe 17, and the opening area of the auxiliary intake pipe 18 in the peripheral wall of the main intake pipe 17 is reduced. As indicated by the dotted line, the opening / closing valve 20 can be made smaller than when the auxiliary intake pipe 18 is connected to a portion of the main intake pipe 17 other than the curved portion.

In addition, this embodiment can also be changed and embodied as follows.
As shown in FIG. 3B, the shape of the inlet 15 of the air cleaner 14 and the cross-sectional shape of the flow path of the main intake pipe 17 are both circular. Or it is made into an ellipse.

As shown by a two-dot chain line in FIG. 1B, the opening / closing valve 20 is supported by a support shaft 21 provided at the center in the width direction of the flow path of the auxiliary intake pipe 18.
As shown by a two-dot chain line in FIG. 1B, the auxiliary intake pipe 18 extends from the peripheral wall outside the curved portion of the main intake pipe 17 so as to bend from the opening direction of the inlet 15 of the air cleaner 14. Let

  -Instead of the negative pressure actuator 22, a step motor of a type that directly moves the operating shaft is provided. In this case, instead of the operating shaft 23 of the negative pressure actuator 22, the open / close valve 20 is opened / closed by advance / retreat of the operating shaft of the step motor. Alternatively, an ordinary stepping motor of a type that rotates the shaft is provided, and the opening / closing valve 20 is opened and closed by rotating the support shaft 21.

(A) is a plane sectional view showing an intake pipe of an intake device of one embodiment, and (b) is a plane sectional view showing an intake pipe similarly. The schematic diagram which shows the engine system provided with the variable intake device. (A) is the sectional view on the aa line in FIG. 2, (b) is the sectional view equivalent to the aa line which shows a modification. The schematic diagram which shows the engine system provided with the conventional intake device. Bb sectional view taken on the line in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Gasoline engine as an internal combustion engine, 14 ... Air cleaner, 15 ... Inlet, 16 ... Intake device, 17 ... Main intake pipe, 17a ... Connection part opening, 18 ... Sub-intake pipe, 19 ... Recessed part, 20 ... Open / close valve, 21 ... support shaft.

Claims (5)

In a variable intake device for an internal combustion engine comprising a main intake pipe connected to an inlet of an air cleaner, and an auxiliary intake pipe communicated with the inlet and openable and closable,
The cross-sectional area of the flow path of the main intake pipe is equal to or larger than the cross-sectional area of the inlet of the air cleaner, and the auxiliary intake pipe communicates with the inlet through the main intake pipe. A variable intake system for an internal combustion engine.   The variable intake device for an internal combustion engine according to claim 1, wherein the auxiliary intake pipe extends in an opening direction of the inlet of the air cleaner.   An open / close switching valve is rotatably supported at one end of the auxiliary intake pipe, and the open / close valve is disposed at a closed position forming a part of the peripheral wall of the main intake pipe. The variable intake device for an internal combustion engine according to claim 1 or 2, wherein the variable intake device is configured as described above.   The recessed part is formed in the surrounding wall of the said sub intake pipe, The opening-and-closing valve arrange | positioned in the open position was accommodated in the recessed part, The Claim 1 characterized by the above-mentioned. Variable intake device for internal combustion engine.   The main intake pipe is bent so as to change the direction of the flow path after extending in the opening direction of the inlet of the air cleaner, and the auxiliary intake pipe is introduced from the peripheral wall outside the curved portion of the main intake pipe. The variable intake device for an internal combustion engine according to any one of claims 1 to 4, wherein the variable intake device is extended in an opening direction of the mouth.

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