JPH09125969A - Variable intake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the controllability of engine speed, particularly responsiveness when the engine is in the low speed range, or the like, by reducing relatively the volume of a downstream side intake passage connected to the downstream side of the upstream side intake introducing part of the intake system of the engine. SOLUTION: This variable intake device includes a fixed intake pipe 43 communicated with a combustion chamber; a movable intake pipe 42 which is fitted to the pipe 43 and is continuously movable between a longest intake passage position P1 where its length overlapping with the fixed intake pipe is shortest and a shortest intake passage position P0 where the length is longest; an upstream side intake introducing part which is connected to the upstream end of the movable intake pipe 42 when the movable intake pipe 42 is at the longest intake passage position P1 and to which intake is guided via an air cleaner; and casing members 40, 39 which, when the movable intake pipe 42 is at the longest intake passage position P1, accommodate the movable intake pipe 42 and connect the upstream side intake introducing part to the fixed intake pipe 43 and whose inner surfaces are shaped to extend along a track on which the movable intake pipe 42 moves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable intake system provided in an intake system of an engine, and more particularly, to a fixed intake pipe and a movable intake pipe by varying the amount of superposition of the fixed intake pipe and the movable intake pipe. The present invention relates to a variable intake device that changes the length of a typical intake branch passage.

[0002]

2. Description of the Related Art An intake system of an internal combustion engine is designed to allow intake air from an intake port on the air cleaner side to flow into an intake port of the engine. Usually, the throttle body is provided with an air cleaner, an intake pipe, and a throttle valve for adjusting the intake amount. , A surge tank that interferes with intake pulsation of other cylinders, and an intake system constituent member such as an intake manifold that branches intake air into each cylinder are sequentially connected. The intake path length is determined by sequentially connecting the respective intake system constituent members to each other, and the length is usually constant.

By the way, it is known that the volumetric efficiency of an engine changes depending on the engine speed and the length of the intake pipe, which is considered to be due to the pulsation effect and the inertial effect of the intake pipe. Here, the pulsating effect is caused by the fact that the negative pressure wave generated in the intake port at the time of opening the intake valve reciprocates between this intake port and the atmospheric pressure equivalent part side of the intake pipe and then returns as a positive pressure wave. The inertial effect is caused by the inertia shown by the flow of the air column in the intake pipe. In either case, it is possible to expect the action of pushing the intake air into the cylinder, which can improve the volumetric efficiency.

Further, in a multi-cylinder engine, intake interference may occur between the intake passages of each cylinder, and in order to prevent this, the intake passages of each cylinder are branched from each other until reaching a large capacity surge tank or the like. Has been done. Here, intake interference is
A negative pressure wave generated when the intake valve opens opens through the intake passage and reaches the intake port of another cylinder just before the intake valve closes,
This is a phenomenon that reduces the volumetric efficiency of the cylinder. As described above, when setting the intake system of the engine, an intake pipe line suitable for preventing intake interference and improving engine volume efficiency is set, and in particular, an intake pipe line variable mechanism that can positively use intake pulsation is provided. Proposed.

For example, an intake system for an internal combustion engine shown in FIG. 17 is known. The intake path constituent members of the engine here are the intake ports 1 extending from the respective cylinders, the intake manifolds 2 at their tips, and the housing 3 integrally formed on the upper side of the intake manifolds 2. , A semi-cylindrical rotor 4 that rotates in the housing. The housing 3 includes upper and lower walls 301 and 303, and a suction pipe 3 extending from the upper wall 301.
02 and both side walls 304 and 305. Here, a plurality of variable branch passages r are formed by the outer wall surface of the rotor 4 and a plurality of recessed grooves 305a formed on the side wall 305, and the upstream end of each variable branch passage r communicates with each intake port 1, The downstream end of each variable branch path r communicates with the inner chamber of the housing 3.

Here, when the rotor 4 contacts the flat wall 306 below the upper wall 301 by a predetermined amount, the air from the suction pipe 302 passes through the space sandwiched between the upper wall 301 and the flat wall 306. The variable branch passages r formed by the concave groove 303a and the outer wall surface of the rotor 4 branch off and flow into the intake manifolds 2 and the intake ports 1. Figure 1
In the case of the intake device for an internal combustion engine shown in FIG. 7, the rotor 4 is driven by an actuator shaft 401 directly connected to an actuator (not shown), and the substantial length of the intake branch passage is variably controlled.

In particular, when the engine is in the middle-high rotation range, the edge portion 401 of the rotor 4 is held at the shortest intake passage position P0 which is the end portion of the upper wall 303, and the fixed intake air whose actual intake branch passage length is the shortest. By setting the addition value of the path length L1 and the length of the intake port 1, it is possible to secure the intake inertia action in the middle and high speed regions. On the other hand, when the engine is in the low rotation range, the edge portion 401 of the rotor 4 is moved by the actuator (not shown) so that the flat wall 30
6 is held at the longest intake passage position P1 that abuts 6, and the intake inertia action in the low rotation range can be ensured by setting the substantial intake branch passage length (L1 + L2) and the intake port 1 length as an addition value. An intake device provided with such an intake passage variable mechanism is disclosed in Japanese Patent Laid-Open No. 60-91414. Furthermore, a variable intake system for an engine provided with a plurality of movable intake pipes (only one is shown in FIG. 18) in which a plurality of variable branch passages are completely independent from each other is disclosed in Japanese Patent Application No. 7-1431 of the present inventor.
No. 18 specification and drawings.

As shown in FIG. 18, the variable intake system for this engine uses the surge tank 5 to intake the intake air from the upstream side of the intake system.
A movable intake pipe 7 and a fixed intake pipe which are housed in a housing chamber 10 formed by a lid-shaped casing 6 integrally connected to the side wall of the surge tank 5 and a semicircular casing 12 integrally connected to the surge tank 5. Intake air is introduced into the pipe 8. Further, the intake air that has flowed into the fixed intake pipe 8 is allowed to flow into each intake port (not shown) via the intake manifold 9 that is integrally connected downstream of the fixed intake pipe 8. Here, in the variable intake system, the fixed intake pipe 8 is fixed to the lid-shaped casing 6, and the movable intake pipe 7 is integrally coupled to the drive shaft 11 pivotally supported by the lid-shaped casing 6 via the arm 701. The arc center of each movable intake pipe 7 coincides with the center of the drive shaft 11. Therefore, when the movable intake pipe 7 swings around the drive shaft 11, the inner wall of the movable intake pipe 7 and the outer wall of the fixed intake pipe 8 can swing without interfering with each other.

Also here, when the movable intake pipe 7 is held at the shortest intake passage position P0 where the fixed intake pipe 8 is completely overlapped, and the intake air is introduced into the tip openings 701 of the movable intake pipe 7 and the fixed intake pipe 8. The length of the intake branch passage in the accommodation chamber 10 can be maintained at the shortest length L1, and the intake inertia action in the middle-high speed region of the engine can be secured. Further, when the movable intake pipe 7 is projected to the maximum from the fixed intake pipe 8 and the intake air is made to flow into the tip opening 701 of the movable intake pipe 7 from the surge tank 5, the intake branch path length in the accommodation chamber 10 is the longest. It can be maintained at (L1 + L2), and the intake inertia action in the low engine speed range (when idling, etc.) can be secured.

[0010]

By the way, in the engine intake system disclosed in FIG. 17 and Japanese Patent Laid-Open No. 60-19914, the edge portion 401 of the rotor 4 causes the longest intake passage when the engine is in the low speed region. A throttle valve (not shown) on the upstream side of the suction pipe 302, which is held in the position P1
The volume of the inner chamber surrounded by the side wall 304 of the housing 3, the rotor 4, the upper wall 303, and the flat plate portion 306 is added as the downstream volume of the above. Similarly, in the variable intake system for the engine of the prior art by the applicant shown in FIG. 18, when the engine is in the low speed range and the movable intake pipe 7 is held at the longest intake passage position P1, the throttle valve at that time is held. As a downstream volume, it communicates with the surge tank 5 and also has a lid-shaped casing 6
The volume of the storage chamber 10 surrounded by the low wall 601 and the inner wall surface 121 of the semicircular casing 12 is added.

As described above, in any of the conventional devices, the volume downstream of the throttle valve becomes relatively large when the movable intake pipe 7 is held at the longest intake passage position P1 in the low speed region of the engine. Therefore, in the case of any of the conventional devices, there is a problem that the air accumulated on the downstream side of the throttle valve at the time of engine start tends to excessively flow into the combustion chamber side, and the engine speed excessively increases. Further, even after the start, since the volume downstream of the slot valve is large, there is a problem that the responsiveness at the time of switching the throttle valve and the intake throttle means is relatively low, and the controllability in the idling or low rotation range is low.

An object of the present invention is to reduce the volume of the downstream side intake passage connected to the upstream side intake introducing portion of the intake system in an operating range where the movable intake pipe is held at the longest intake passage position, for example, a low rotation range. The purpose of this is to make it relatively low and improve the controllability of engine rotation, especially the responsiveness.

[0013]

In order to achieve the above-mentioned object, the invention of claim 1 is such that a fixed intake pipe communicating with an engine combustion chamber and an intake passage fitted to an upstream end of the fixed intake pipe. Of at least a part of the movable intake air which forms at least a part thereof and is continuously movable between the longest intake passage position where the overlap length with the fixed intake pipe is the shortest and the shortest intake passage position where the overlap length is the longest. Pipe, an upstream intake port for introducing intake air through an air cleaner, and a movable intake pipe located at an upstream side position of the movable intake pipe, and the movable intake pipe at least at the longest intake passage position. And a casing member that accommodates the movable intake pipe at a certain time to airtightly connect the upstream intake introduction portion and the fixed intake pipe and has an inner surface shape along a locus along which the movable intake pipe moves. Is characterized by.

According to a second aspect of the present invention, in the variable intake system according to the first aspect, the fixed intake pipe is fitted inside the movable intake pipe, and the overlap length of the fixed intake pipe and the movable intake pipe is the longest. And a casing member for accommodating the movable intake pipe inside at the shortest intake passage position.

According to a third aspect of the present invention, in the variable intake system according to the first or second aspect, the fixed intake pipe and the movable intake pipe are formed on an arc having a common center point and the movable intake pipe is formed. The pipe is configured to be supported by the arm member and swing about a swing axis including the center point, and the casing member has a storage chamber for storing the arm member.

According to a fourth aspect of the present invention, in the variable intake system according to the third aspect, the engine has a plurality of cylinders, and the movable intake pipes are arranged in parallel in the cylinder direction corresponding to each cylinder and fixed to each other. The arm members are fixed to both ends in the cylinder side direction.

According to a fifth aspect of the present invention, in the variable intake system according to the fourth aspect, the arm member is located on the swing axis and is connected to a drive mechanism so that the arm member is fixed to the crawler member. Is rotated integrally with the arm member.

According to a sixth aspect of the present invention, in the variable intake system according to the fifth aspect, the casing member has a shaft accommodating portion extending along an axis for accommodating the shaft member between the arm members. Is characterized by.

[0019]

1 to 3 show a variable intake system as one embodiment of the present invention. This variable intake system is installed in an in-line four-cylinder engine (hereinafter simply referred to as engine) 30. Here, the engine 30 has an intake manifold 32 and an exhaust manifold (not shown) integrally connected to the left and right walls of its cylinder head 31. Each tip of the intake manifold 32 passes through the first fixed intake pipe 43 made of resin and the variable intake path length mechanism A for accommodating the movable intake pipe 42 made of resin, and the second fixed intake pipe 33 to the surge tank 34 in order. It is connected.

As shown in FIGS. 1 and 2, the surge tank 3
4 has an intake port 341 formed in the upper part thereof, and the intake port 3
An air cleaner 37 is connected to 41 via a throttle body 35 and an intake pipe 36. Surge tank 34
Has an intake port 341 formed in the side wall of the upstream portion.
As shown in FIG. 4, the inclined convex portion 342 that reduces the convex amount with increasing distance from the suction port 341 is provided, and four openings 343 are formed on the downstream side, and the second fixed intake pipes 33 extend to these openings. It is formed. The tip of the second fixed intake pipe 33 is connected to the intake port 401 in the lid-type casing 40 of the intake path length varying mechanism A. The throttle body 35 is a cylindrical body made of aluminum die-cast, and a throttle valve 38 for variably adjusting the intake air amount is arranged inside thereof.

The throttle valve 38 is a link 38.
1 is connected to a throttle actuator (not shown). Here, the upstream side intake introducing portion including the air cleaner 37, the intake pipe 36, the throttle body 35, the surge tank 34, and the second fixed intake pipe 33, and the intake path length varying mechanism A, the intake manifold 32, and the intake port The total intake pipe length LI, which is the total intake path of the engine 30 (see FIG.
(See reference) is determined, and the length is variably adjusted only by the intake path length varying mechanism A. As shown in FIGS. 1 to 3, the intake path length varying mechanism A forms an outer frame with a bowl-shaped semicircular casing 39 and a lid-shaped lid-type casing 40 integrally connected to the bowl-shaped semi-circular casing 39. The accommodation chamber 41 is sealed. The semi-circular casing 39 has a bowl shape so as not to interfere with a movable intake pipe 42, which will be described later, and has a lid-type casing 40 around the periphery thereof.
To form a flange 391 which is superposed on and bolted to.

On the other hand, as shown in FIG. 5, the lid-type casing 40 is generally in the shape of a rectangular dish having a central protrusion 402.
A flange 403 which overlaps with the semi-circular casing 39 and is bolted is formed on the periphery thereof. The lid-type casing 40 has four intake ports 401 formed on the upstream side wall, and the movable intake pipe 42 is provided at an intermediate position in the height direction (vertical direction of the drawing).
An actuator shaft 44 for swinging the shaft is pivotally supported, and four downstream openings 408 are formed in the side wall on the downstream side. The fixed intake pipe 4 is integrally formed at each downstream opening 408 of the lid-type casing 40.
Four of the fixed intake pipes 43 are arranged side by side, and each of the fixed intake pipes 43 is formed to have an arcuate cross-section in the longitudinal direction, and the arcuate center is formed to coincide with the center line L0 of the actuator shaft 44.

The curved space 4 forming the main part of the storage chamber 41
11 is formed between the central projection 402 of the lid-type casing 40 and the inner wall of the semi-circular casing 39, and the curved space 411.
The movable intake pipe 42 fitted inside the fixed intake pipe 43 can be rotated around the center line L0. In particular, here, the movable intake pipe 42
Is rotated around the center line L0, the lid-type casing 40
The volume of the curved space 411 is narrowed within a range where it does not interfere with the central protrusion 402 of the above and the inner wall of the semicircular casing 39, that is,
The movable intake pipe 42 is formed so as to have an inner surface shape along the moving trajectory of the movable intake pipe 42, thereby reducing the volume of the intake passage on the downstream side of the throttle valve 38, and responding to engine speed fluctuations associated with the opening / closing operation of the throttle valve. Is improving. As shown in FIG. 5, the actuator shaft 44 has its left and right ends pivotally attached to the lid-type casing 40 via bearings 45.
Two left and right arms 27 are integrally connected to two points from the left and right ends. Here, the four movable intake pipes 42 corresponding to each cylinder are arranged in parallel in the cylinder direction and are integrally coupled to each other, and the two movable arms 27 are respectively connected to the left and right ends of the four movable intake pipes 42. The moving ends are integrally connected.

Here, the lid-type casing 40 has a valley portion 404 as a laterally long shaft accommodating portion at the center of the central projecting portion 402.
Is recessed, and the actuator shaft 44 is housed on the lower wall side of the valley portion 404. Further, upright walls 405 are formed at the left and right ends of the central protrusion 402, and a vertical groove 407 is formed between the upright wall 405 and the side wall 406 of the lid-type casing 40. The vertical groove 407 can accommodate two left and right arms 27 that rotate around the actuator shaft 44 without interfering with each other. A direct-current motor 28, which is an actuator for varying the intake pipe length, is connected to one end of the actuator shaft 44 via a reduction mechanism (not shown). In this DC motor 28, the movable intake pipe 42 slides with respect to the fixed intake pipe 43,
It is driven by the controller 47. The controller 47 drives the movable intake pipe 42 fitted onto the first fixed intake pipe 43, and holds the movable intake pipe 42 at a predetermined position in the axial direction position of the second passage R2 formed by the first fixed intake pipe 43. Drive to do it.

The tip end opening 431 of the first fixed intake pipe 43 is arranged at a substantially intermediate position in the height direction of the accommodation chamber 41, so that the intake air is directly introduced into the tip end opening 431 from the intake port 401. If the intake pipe length variable mechanism A
It is set so that the intake branch path length in the inside can be held at the shortest LA and the intake pulsation operation at the maximum output of the engine can be secured. On the other hand, the movable intake pipe 42 is formed to have an inner diameter that fits over each of the first fixed intake pipes 43 and the second passage R2.
To form a first passage R1. Here, each of the four movable intake pipes 42 arranged in parallel in the cylinder direction and fixed to each other corresponding to each cylinder is formed in an arc shape in its longitudinal cross-section, and the arc center is the center line of the actuator shaft 44. Match L0. Therefore, the four movable intake pipes 42 can be simultaneously swung about the actuator shaft 44.

As shown in FIG. 3, the movable intake pipe 42 has the maximum intake passage position P1 (the position shown by the solid line in FIG. 3) at which the movable intake pipe 42 protrudes the maximum from the fixed intake pipe 43.
When the intake air is made to flow into the funnel-shaped front end opening 421 of No. 2, the intake branch path length in the intake pipe length variable mechanism A can be held at the longest LA + LM. Here, a resin cylindrical seal 45 is fitted on the inner peripheral wall of the suction port 401 of the lid-type casing 40. As shown in FIG. 14, the tubular seal 4
Reference numeral 5 denotes an annular projection 451 that is locked in the annular recess 40a on the inner peripheral wall of the suction port 401, and a sealing property with respect to the tip of the second fixed intake pipe 33 that is formed on the side wall of the annular projection 451. A seal projection 452, a bellows portion 453 extending to the opposite side of the annular projection 451, a tubular first lip 454 extending from the tip of the bellows portion 453 in the direction of the seal center axis Ls (see FIG. 14), Second extending in the radial direction B of the seal
And a lip 455. Moreover, the first and second lips 454, 455 of the tubular seal 45 are formed so as to contact the inner wall surface of the funnel-shaped tip opening 421.

The funnel-shaped front end opening 421 of the movable intake pipe is the first and second lips 45 of the tubular seal 45.
Even if the pressure contact state with 4,455 is slightly increased or decreased, the bellows part 4
53 works, and the first and second lips 454, 455 and the front end opening 421 can surely come into contact with each other. Therefore, even if the tip opening 421 is displaced due to rattling in the rotary drive system between the actuator shaft 44 and the DC motor 28, the bellows 453 can absorb the displacement. Moreover, when the internal pressure of the intake pipe becomes negative, the second lip 455 extending in the seal radial direction B comes into pressure contact with the tip opening 421, and conversely,
When the pressure in the accommodation chamber 41 side outside the intake pipe becomes negative, the cylindrical first lip 45 extending in the seal central axis Ls direction can be pressed against the tip opening 421 to ensure the sealing performance inside and outside the intake pipe. As shown in FIG. 16, a recess 423 is formed at the rear end of the movable intake pipe 42, and a seal ring 46 is fitted in the recess 423.

Here, an annular protruding portion 432 is formed at the tip of the first fixed intake pipe 43, and the small diameter portion 4 is connected to the annular protruding portion 432 and the small diameter portion 433 forming a sliding contact surface.
A tapered portion 434 whose diameter gradually changes from 33 to the annular protrusion 432 is provided. Therefore, the seal ring 32 of the elastic body can be slidably contacted with the outer peripheral surface of the small diameter portion 433 of the other fixed intake pipe 43 to smoothly slide, and the sliding resistance is reduced to improve the responsiveness of the variable intake mechanism portion. Can be secured. Further, only when the movable intake pipe is at the longest intake passage position P1, the seal ring 46 can come into air-tight contact with the annular protrusion 432, and the gap between both intake system pipes can be reliably sealed, so that the low rotational speed range is achieved. A stable intake inertia effect can be obtained. Further, the accuracy error between the movable intake pipe 42 and the fixed intake pipe 43 can be absorbed, and the deterioration of controllability due to the occurrence of a short-circuit airflow can be prevented. The assembling accuracy of the first and second intake passage pipes may be relatively low. Cost can be reduced.

The above-mentioned cylindrical seal 45 and seal ring 4
6 may be made of a material having a low friction coefficient, and is made of NBR resin here. The tubular seal 45 and the seal ring 46 may be made of Teflon resin or metal having a low friction coefficient. When such a variable intake device is driven, the controller 47 drives the movable intake pipe 42 around the rotation axis 44 via the DC motor 46 in the low rotation range including the idle operation of the engine 30, so that the movable intake pipe 42 has the longest length. Move to the intake passage position P1.

In this case, the tip opening 42 of the movable intake pipe 42
2 is pressed against the tubular seal 45, and the seal ring 46 can reliably seal between the movable intake pipe 42 and the annular protruding portion 432.
It is possible to seal between the accommodation chamber 41 side and the inside of the intake passage. When the intake air is introduced from the upstream intake introduction portion side including the air cleaner 37 to the second fixed intake pipe 33, the intake branch path length in the intake pipe length variable mechanism A is defined as the first fixed intake path length LA. The second fixed intake passage length LB, which can be maintained at the addition value (LA + LM) of the movable intake pipe length LM, and which is formed by the flow passage of the second fixed intake pipe 33 (shown by hatching in FIG. 3) is continuously added. (See FIG. 4).

Therefore, as shown in FIG. 15, assuming that the intake path length of the intake manifold 32 and the intake port 29 is LP, the substantial intake branch path length L _T of each cylinder of the engine is the longest. LP + LA + LM + LB), where
It is possible to sufficiently secure the intake inertia action in the low speed range such as when the engine is idle. Moreover, at this time, the throttle valve 3
Since the volume of the intake chamber on the downstream side of 8 does not include the volume of the accommodation chamber 41, the responsiveness of the engine rotation fluctuation due to the opening / closing operation of the throttle valve can be improved, and the engine rotation in the low rotation range can be stabilized.

On the other hand, when the engine reaches the high speed range, the controller 47 causes the movable intake pipe 42 to move through the DC motor 28.
Is driven around the actuator shaft 44 to move the movable intake pipe 42.
The front end opening 422 of the above is moved to the shortest intake passage position P0.
The substantial intake branch path length L _T of each cylinder of the engine in this high rotation range is (LP + LA), and is maintained at the shortest length,
The pressure wave in each intake branch passage is inverted in the accommodation chamber 41, and it is possible to secure the intake pulsation operation at the maximum output of the engine and contribute to the output improvement. Note that, in FIG. 15, reference numeral LI indicates the entire intake passage of the engine 30.

As described above, according to the variable intake system of FIG. 1 to which the present invention is applied, since the casing members 40 and 39 have an inner surface shape along the locus along which the movable intake pipe 42 moves, the casing volumes are compared. The air cleaner 37 and the second fixed intake pipe 33 are provided when the operating range is such that the movable intake pipe 42 can be made smaller and the movable intake pipe 42 is kept at the longest intake passage position P1, for example, when the engine is in a low rotation range such as an idle operating range. It is possible to relatively reduce the volume of the downstream intake passage connected to the upstream intake introduction portion, improve the engine responsiveness associated with intake air amount control (control by the throttle valve 38, etc.), and improve engine controllability. improves.

In particular, the first fixed intake pipe 43 is the movable intake pipe 4
2 and the lid type casing 40 and the semicircular type casing 39 which accommodate the movable intake pipe inside when the fixed intake pipe and the movable intake pipe are at the shortest intake passage position P0 where the overlap length of the movable intake pipe is the longest. The casing member may be provided.
In this case, when the movable intake pipe 42 is located at the shortest intake passage position P0, the movable intake pipe 42 is airtightly connected to the upstream intake introduction portion (surge tank 34 side) inside the casing members 40 and 39, so The change in the volume of the intake passage at the time of switching between when the movable intake pipe 42 is in contact with the intake passage position P0 and when it is not is relatively small, and the fluctuation of the engine rotation at the time of switching can be relatively reduced.

In particular, the first fixed intake pipe 43 and the movable intake pipe 4
2 is formed on an arc having a common center point L0, the movable intake pipe 42 is supported by the arm member 27, and the arm member 27 is centered on the center point L0 while being housed in the housing chamber 41 of the casing member. You may swing to. In this case, there is an advantage that it is relatively easy to adjust the interference when the movable intake pipe 42 swings with respect to the first fixed intake pipe 43.
In particular, the engine 30 may have a plurality of cylinders, the movable intake pipes may be arranged in parallel in the cylinder direction and fixed to each other, and the arm members 27 may be fixed to both ends in the cylinder side direction. . In this case, even if the engine has a plurality of cylinders, the first
There is an advantage that it is relatively easy to adjust interference when the movable intake pipes 42 swing with respect to the fixed intake pipe 43.

In particular, the arm member 27 is on the swing axis (L0
The arm member 27 may be located on the upper side and connected to the DC motor 28, the arm member 27 may be fixed to the actuator shaft 44, and the actuator shaft 44 may rotate integrally with the arm member. In this case, the arm member 27 integrated with the actuator shaft 44 connected to the DC motor 28 can simultaneously swing the movable intake pipes 42 corresponding to the cylinders. In particular, the casing members 40, 39 may have valleys 404 extending along the axis to accommodate the actuator shaft 44 between the arm members 27. In this case, the actuator shaft 4 between the arm members 27 is excluded by eliminating an excessively large space.
4 is formed, the volume of the storage chamber 41 can be made relatively small also in this respect, and the volume of the downstream intake passage connected to the upstream intake introduction portion of the intake system can be relatively reduced. Therefore, it is possible to improve the responsiveness of the engine rotation due to the intake air amount control, and the engine controllability is improved.

[0037]

EFFECTS OF THE INVENTION A movable intake pipe fitted to a fixed intake pipe communicating with an engine combustion chamber and capable of continuously moving between a longest intake passage position and a shortest intake passage position, and intake air through an air cleaner. The movable intake pipe has a shortest overlap length with the fixed intake pipe, and includes an upstream intake air introduction part to be guided and a casing member that accommodates the movable intake pipe and airtightly connects the upstream intake air intake part and the fixed intake pipe. At the longest intake passage position, the upstream intake passage, the movable intake pipe, and the fixed intake pipe are airtightly connected.

Therefore, since the casing member has an inner surface shape along the locus along which the movable intake pipe moves, the volume of the casing can be made relatively small, and the operating range in which the movable intake pipe is held at the longest intake passage position, For example, when the engine is in a low rotation range such as an idle operation range, the volume of the downstream intake passage connected to the upstream intake introduction section of the intake system can be relatively reduced, and the response of the engine rotation accompanying the intake amount control can be reduced. It is possible to improve the engine controllability.

[Brief description of the drawings]

FIG. 1 is a partially cutaway schematic side sectional view of a variable intake device according to an embodiment of the present invention.

2 is a partially cutaway schematic plan sectional view of the variable intake device in FIG. 1. FIG.

FIG. 3 is an enlarged cutaway sectional view of a variable intake path length mechanism in the variable intake device of FIG.

FIG. 4 is an operation characteristic explanatory diagram of an intake path length varying mechanism in the variable intake device of FIG.

5 is an enlarged plan view of a lid-type casing of the variable intake pipe length mechanism in the variable intake device of FIG. 1. FIG.

6 is a side view of a lid-type casing of the variable intake pipe length mechanism in the variable intake device of FIG.

7 is a side view of the lid-type casing in the direction of arrow E in FIG.

8 is a side view of the lid-type casing in the direction of arrow F in FIG.

FIG. 9 is a sectional view taken along line DD of FIG. 5;

10 is a sectional view taken along line BB of FIG.

11 is a cross-sectional view taken along the line AA of FIG.

12 is a sectional view taken along line GG of FIG.

13 is a cross-sectional view taken along the line CC of FIG.

FIG. 14 is an enlarged cross-sectional view of a tubular seal in the variable intake pipe length mechanism of the variable intake device in FIG.

FIG. 15 is a schematic diagram for explaining the switching operation of the intake passage of the variable intake device of FIG.

16 is an enlarged cross-sectional view of a seal portion between a first fixed intake pipe and a movable intake pipe in the intake pipe length varying mechanism of the variable intake device in FIG.

FIG. 17 is a sectional view of a main part of a conventional variable intake system for an engine.

FIG. 18 is a sectional view of a main part of another conventional variable intake system for an engine.

[Explanation of symbols]

28 DC motor 30 Engine 32 Intake manifold 33 Second fixed intake pipe 34 Surge tank 35 Throttle body 37 Air cleaner 39 Semi-circular casing 40 Lid casing 401 Intake port 402 Center protrusion 404 Valley 405 Upright wall 406 Side wall 407 Vertical groove 41 Storage chamber 42 Movable intake pipe 421 Tip opening 43 First fixed intake pipe 44 Actuator shaft 45 Cylindrical seal 453 Bellows 454 First lip 455 Second lip A Intake pipe length variable mechanism R1 Fixed intake passage R2 Movable intake passage P0 Shortest intake passage position P1 longest intake passage position LP intake passage length LA first stationary intake pipe length LB second stationary intake passage length LM movable intake pipe length L _T branch intake passage length of the intake manifold and the intake port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Kumagai 5-3-8 Shiba, Minato-ku, Tokyo, Mitsubishi Motors Corporation (72) Inventor Hideo Nakai 5-33-8 Shiba, Minato-ku, Tokyo・ Inside Mitsubishi Motors Corporation (72) Inventor Hiroyuki Kiuchi 4-21-1, Shimomaruko, Ota-ku, Tokyo ・ Inside Mitsubishi Motors Engineering Co., Ltd.

Claims (6)

[Claims] 1. A fixed intake pipe communicating with an engine combustion chamber,
The fixed intake pipe is fitted to the upstream end to form at least a part of the intake passage, and the longest intake passage position where the overlap length with the fixed intake pipe is the shortest and the shortest intake pipe where the overlap length is the longest. A movable intake pipe that can be continuously moved to and from the passage position, and a throttle valve that is located at an upstream position of the movable intake pipe, and upstream intake air introduction that guides intake air through an air cleaner. Part and the movable intake pipe at least at the longest intake passage position, the movable intake pipe is accommodated to airtightly connect the upstream intake introduction part and the fixed intake pipe and the locus of movement of the movable intake pipe. And a casing member having an inner surface shape along the variable intake device. 2. The variable intake system according to claim 1, wherein the fixed intake pipe is fitted inside the movable intake pipe, and the fixed intake pipe and the movable intake pipe have a longest overlap length. A variable intake device comprising a casing member that accommodates the movable intake pipe inside when in the position. 3. The variable intake system according to claim 1 or 2, wherein the fixed intake pipe and the movable intake pipe are formed on an arc having a common center point, and the movable intake pipe is an arm member. A variable intake device, which is configured to be supported and swing about a swing axis including the center point, and wherein the casing member has a storage chamber for storing the arm member. 4. The variable intake system according to claim 3, wherein the engine has a plurality of cylinders, and the movable intake pipes are arranged in parallel in the cylinder direction so as to correspond to the respective cylinders and fixed to each other. A movable intake device, wherein the arm members are fixed to both ends in the direction. 5. The variable intake system according to claim 4, wherein the arm member is located on a swing axis and is connected to a drive mechanism, the arm member is fixed to the shaft member, and the shaft member is the arm member. A variable intake device that rotates together with the variable intake device. 6. The variable intake system according to claim 5, wherein the casing member has a shaft accommodating portion extending along an axis for accommodating the shaft member between the arm members. Inhaler.