JPH09125968A - Variable intake device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an intake inertial effect in the low engine speed range of an engine such as an idle operating range so as to enhance outputs by securing a sufficiently great substantial length of an intake branch line when a movable intake pipe is projected from a fixed intake pipe by a maximum amount. SOLUTION: This variable intake device includes a first fixed intake pipe 43 communicated with an engine combustion chamber; a movable intake pipe 42 which is fitted to the upstream end of the first fixed intake pipe to form at least a part R1 of an intake passage and is continuously movable between a longest intake passage position P1 where its length overlapping with the first fixed intake pipe 43 is shortest and a shortest intake passage position P0 where the overlap length is longest; and a second fixed intake pipe 33 which is communicated at its upstream end with an intake volume chamber such as a surge tank and which is intimately contacted at its downstream end with the upstream end of the movable intake pipe 42 when the movable intake pipe 42 is at the longest intake passage position P1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake device,
In particular, the present invention relates to a variable intake device for an engine that varies a mutual overlapping amount of a fixed intake pipe and a movable intake pipe in an intake passage constituting member of an intake system to change a substantial intake passage length.

[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. 21 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. FIG. 2
In the case of the intake device for an internal combustion engine shown in FIG. 1, the rotor 4 is driven by an actuator shaft 401 directly connected to an actuator (not shown), and the substantial intake branch path length is variably controlled as shown in FIG.

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 substantial intake branch passage length is the longest (L1 + L2), the intake inertia action in the low rotation range can be secured by adding the length of the intake port 1. An intake device provided with such an intake passage variable mechanism is disclosed in Japanese Patent Laid-Open No. 60-91414.

Further, a plurality of movable supply pipes in which a plurality of variable branch passages are completely independent of each other (only one is shown in FIG. 23)
A variable intake system for an engine including the above is disclosed in the specification and drawings of Japanese Patent Application No. 7-143118 by the present inventor.
The variable intake system for this engine, as shown in FIG.
Intake air from the upstream of the intake system is sucked into the surge tank 5, and the storage chamber 10 formed by the lid-shaped casing 6 integrally connected to the side wall of the surge tank 5 and the semicircular casing 12 integrally connected thereto. Intake air is introduced into the movable intake pipe 7 and the fixed intake pipe 8 which are housed inside. 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 fixed intake pipe 8 are
Can swing without interfering with the outer wall of the.

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 shortest intake path length L in the storage chamber 10
It can be maintained at 1, and the intake inertia action in the middle and high engine speed range can be secured. Furthermore, the movable intake pipe 7 is replaced with the fixed intake pipe 8
When the intake air is made to protrude further to the maximum and the intake air is made to flow from the surge tank 5 into the distal end opening 701 of the movable intake pipe 7,
It is possible to keep the intake branch path length in the longest (L1 + L2), and to secure the intake inertia action in the low engine speed range (when the engine is idle, etc.).

[0010]

By the way, in the engine intake device disclosed in FIG. 21 and Japanese Patent Laid-Open No. 60-19914, the inner wall surface between the outer wall surface of the rotor 4 and the concave grooves 305a on the side wall 305. If a predetermined amount of gap is not secured between the rotor 4 and 305b, the rotor 4 will not rotate smoothly, and if this gap is excessively formed, intake interference will occur between adjacent movable branch passages, resulting in a reduction in volumetric efficiency. Cause problems. On the other hand, in the prior art by the applicant shown in FIG. 23, the variable range of the variable intake passage is the length of the movable intake pipe 7 (L2 in FIG. 23), and the length of the movable intake pipe 7 is It is necessary to be substantially the same as the total length of the fixed intake pipe 8 at the shortest time of the variable intake passage (when it is at the P0 position). For this reason, the variation width of the variable intake passage, particularly the maximum length, cannot be sufficiently taken within the variation range of the engine speed, and the effect of inertial supercharging cannot be sufficiently obtained, which is a problem. ing.

An object of the present invention is to ensure a sufficiently long substantial intake branch passage length when the movable intake pipe is protruded by the maximum amount with respect to the fixed intake pipe. Variable intake of the engine that secures the sealing property when connecting with the pipe and reliably eliminates the occurrence of short-circuit airflow, obtains the intake inertia effect in the low rotation range such as the idle operation range of the engine, and stabilizes the engine rotation To provide a device.

[0012]

In order to achieve the above object, the invention of claim 1 fits a first fixed intake pipe communicating with an engine combustion chamber and an upstream end of the first fixed intake pipe. To form at least a part of the intake passage and to continuously connect between the longest intake passage position where the overlap length with the first fixed intake pipe is the shortest and the shortest intake passage position where the overlap length is the longest. A movable intake pipe that can move to the upstream side of the movable intake pipe and the upstream end of the movable intake pipe communicates with the intake volume chamber or the atmosphere opening port. Two fixed intake pipes are provided.

According to a second aspect of the present invention, in the variable intake system for an engine according to the first aspect, an air purifying device is arranged upstream of the second fixed intake pipe and the movable intake pipe is built inside. And a casing member that connects the first fixed intake pipe and the second fixed intake pipe so that only air that has passed through the second fixed intake pipe is introduced into the first fixed intake pipe. To do.

According to a third aspect of the present invention, in the variable intake system for an engine according to the first or second aspect, either of the second fixed intake pipe downstream end portion or the movable intake pipe upstream end portion is provided with the above. A resin sealing member (elastic member) is provided which abuts on the other side when the movable intake pipe is at the longest passage position.

According to a fourth aspect of the present invention, in the variable intake system for an engine according to the third aspect, the second portion of the movable intake pipe is provided.
The end on the fixed intake pipe side is formed in a funnel shape, and the end on the movable intake pipe side of the resin seal member is formed with a first lip extending in the axial direction and a second lip extending in the radial direction, and Both the first and second lips are formed so as to abut the end of the movable intake pipe.

The invention of claim 5 is the invention of claims 1 to 3.
In the variable intake system for an engine described above, the fixed intake pipe and the movable intake pipe are formed on an arc having a common center point, and the movable intake pipe swings about the center point. To do.

According to a sixth aspect of the present invention, a casing member isolated from the outside air is provided, and in the casing member, a fixed fixed intake pipe and a position connected to the end of the fixed intake pipe and the end thereof are connected. A movable intake pipe that is movable between the separated positions is provided, and the end portion of one intake pipe is formed in a funnel shape and a resin seal ring is arranged on the other intake pipe. The seal ring has a first lip extending in the axial direction and a second lip extending in the radial direction at the end on the movable intake pipe side, and the end of the movable intake pipe contacts the resin seal ring. To do.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an engine variable intake system as an embodiment of the present invention. The variable intake system for this engine is an in-line 4-cylinder engine (hereinafter simply referred to as engine) 3
It is attached to 0. 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 is sequentially connected to a surge tank 34 via an intake path length varying mechanism A that accommodates a first fixed intake pipe 43 and a movable intake pipe 42, and a second fixed intake pipe 33.

As shown in FIGS. 1, 2 and 3, the surge tank 34 has an intake port 341 formed in its upper portion, and the intake port 341 has a throttle body 35 and an intake pipe 3.
An air cleaner 37 is communicated via 6. The surge tank 34 has a suction port 341 formed on the upstream side wall, and in plan view, as shown in FIG. 2, is provided with an inclined convex portion 342 that reduces the convex amount as it moves away from the suction port 341, and is shown in FIG. As described above, the four openings 343 are formed on the downstream side, and the second fixed intake pipes 33 are formed to extend through these openings. The tip of the second fixed intake pipe 33 has an inlet 401 in the lid-type casing 40 of the intake path length varying mechanism A.
Connect to 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 intake system components such as the air cleaner 37, the intake pipe 36, the throttle body 35, the surge tank 34, the second fixed intake pipe 33, the intake path length variable mechanism A, the intake manifold 32, and the intake port 29 are sequentially connected. As a result, the total intake pipe length, which is the total intake passage length of the engine 30, is determined, and the length is variably adjusted only by the intake passage 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 semicircular casing 39 has a bowl shape so as not to interfere with a movable intake pipe 42, which will be described later, and a flange 391 is formed around the periphery of the semicircular casing 39, which is overlapped with the lid casing 40 and bolted.

On the other hand, as shown in FIG. 5, the lid-type casing 40 generally has a rectangular dish shape 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.

A curved space 411 forming a main part of the storage chamber 41 in FIG. 3 is formed between the central projection 402 of the lid-type casing 40 and the inner wall of the semicircular casing 39, and a fixed intake air is provided in the curved space 411. Movable intake pipe 42 fitted onto pipe 43
Can rotate around the center line L0. In particular, here, when the movable intake pipe 42 rotates about the center line L0, the volume of the curved space 411 is narrowed within a range that does not interfere with the central projection 402 of the lid-type casing 40 or the inner wall of the semicircular casing 39. As a result, the volume of the intake passage on the downstream side of the throttle valve 38 is reduced, and the responsiveness of the engine rotation fluctuation due to the opening / closing operation of the throttle valve is improved.

As shown in FIG. 5, the actuator shaft 44
The left and right ends of the lid type casing 4 via bearings 45.
It is pivotally attached to 0, and two left and right arms 27 are integrally connected to two points from the left and right ends. Here, 4 corresponding to each cylinder
The two movable intake pipes 42 are arranged in parallel in the cylinder direction and are integrally connected to each other, and the turning ends of each of the two arms 27 are integrally connected to the left and right ends of the four movable intake pipes 42. Here, the lid-type casing 40 is provided with a laterally long valley 404 recessed in the center of the central projection 402 thereof, and the actuator shaft 44 is accommodated on the lower wall side of the valley 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. This vertical groove 4
Each of the left and right two wheels 07 rotates about the actuator shaft 44.
The book arm 27 can be accommodated without interference.

A DC motor 28, which is an actuator for varying the intake pipe length, is connected to one end of the actuator shaft 44 through a reduction mechanism (not shown). This DC motor 28
Is driven by the controller 47 so that the movable intake pipe 42 slides with respect to the fixed intake pipe 43. 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. To drive. Here, the resin-made first fixed intake pipe 43 is provided with its tip opening 431 at a substantially middle position in the height direction of the accommodation chamber 41, whereby intake air is directly introduced into the tip opening 431 from the intake port 401. In this case, the intake pipe length in the variable intake pipe length mechanism A can be maintained at the shortest LA, and the intake pulsation operation at the maximum output of the engine can be secured.

On the other hand, like the first fixed intake pipe 42, the movable movable intake pipe 42 made of resin is formed to have an inner diameter that is fitted onto each first fixed intake pipe 43 and communicates with the second passage R2. To form. 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. L0
Matches 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 a funnel-shaped tip opening 421 of the movable intake pipe 42 at a maximum intake passage position P1 (position shown by a 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 intake manifold, the intake branch passage length in the intake pipe length varying mechanism A can be held at the longest LA + LM.

Here, the suction port 40 of the lid-type casing 40
A cylindrical seal 45 made of resin is fitted on the inner peripheral wall of the No. 1.
As shown in FIG. 14, the tubular seal 45 has a suction port 401.
Annular protrusion 451 locked in the annular recess 40a of the inner peripheral wall of the
And the second fixed intake pipe 3 formed on the side wall of the annular protrusion 451.
3, a seal ridge 452 for ensuring a sealing property with respect to the tip end portion of No. 3, a bellows portion 453 extending on the opposite side of the annular projection portion 451, and a seal center axis Ls from the tip of the bellows portion 453.
(See FIG. 14) Cylindrical first lip 454 extending in the direction of
And a second lip 455 extending in the seal radial direction B. 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.

Here, the funnel-shaped tip opening 421 of the movable intake pipe is timely swung and held at the longest intake passage position P1 by the DC motor 28 via the arm 27 and the actuator shaft 44. Longest intake passage position P
No. 1 tip opening 421 and first and second cylindrical seal 45
The pressure contact state with the lips 454 and 455 is relatively large.
In the case as shown in FIG. 5, conversely, even in the case where the pressed state is relatively small, as shown in FIG.
3 work together, and the first and second lips 4 of the tubular seal 45 together.
54,455 and tip opening 421 can contact reliably.
In this case, when the tip opening 421 reaches the longest intake passage position P1 shown in FIG. 15 at the time of switching, the tip opening 421 is shown in FIG. 16 due to rattling between the actuator shaft 44 and the DC motor 28. Even if the position is deviated, the amount of the deviation is absorbed by the bellows portion 453, and the first and second lips 454, 455 and the tip end opening portion 421 can surely come into contact with each other.

Further, when the intake pipe internal pressure becomes negative after the tip opening 421 reaches the longest intake passage position P1 and the accommodation chamber 41 side outside the intake pipe becomes positive pressure, as shown in FIG. The second lip 455 extending in the seal radial direction B is displaced so as to come into pressure contact with the tip opening 421 to ensure the sealing performance inside and outside the intake pipe, and conversely, the internal pressure of the intake pipe becomes positive and the outside of the intake pipe is accommodated. When the pressure on the chamber 41 side becomes negative, as shown in FIG. 18, the cylindrical first lip 45 extending in the direction of the seal central axis Ls (see FIG. 14) is displaced so as to come into pressure contact with the tip opening 421, and the intake air is sucked. It is possible to secure the sealing property inside and outside the pipe. As shown in FIG. 19, 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.

On the other hand, an annular projecting portion 432 is formed at the tip of the first fixed intake pipe 43, and the small diameter portion 43 is connected to the annular projecting portion 432 and the small diameter portion 433 forming a sliding contact surface.
A tapered portion 434 having a diameter that gradually changes from 3 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 contact the annular protrusion 432 in an airtight manner, and the gap between both intake system pipes can be ensured by the pressure difference between the inside and outside of the movable intake pipe. It is possible to seal in, and the intake inertia effect in the low speed range can be obtained stably. 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 seal ring 46 may be made of a material having a low friction coefficient, and is made of NBR resin here. The seal ring 46 may be made of Teflon resin or metal having a low coefficient of friction. When such an intake device of the engine is driven, the controller 47 drives the movable intake pipe 42 around the rotation shaft 44 through the DC motor 46 in the low rotation range including the idle operation of the engine, and the movable intake pipe 42 is longest. Move to the intake passage position P1. In this case, the funnel-shaped tip opening 422 of the movable intake pipe 42 is in pressure contact with the tubular seal 45, the seal ring 46 can reliably seal between the movable intake pipe 42 and the annular protrusion 432, and the accommodation chamber 41 side and the intake passage The inside can be sealed. When the intake air is introduced from the surge tank 34 side, the intake pipe length in the intake pipe length varying mechanism A can be held at the addition value (LA + LM) of the first fixed intake passage length LA and the movable intake pipe length LM, Moreover, the second fixed intake path length LB formed by the flow path of the second fixed intake pipe 33 (shown by hatching in FIG. 3) is continuously added (see FIG. 4).

Therefore, if the intake passage length of the intake manifold 32 and the intake port 29 is LP, the substantial intake branch passage length L _T of each cylinder of the engine is the longest, (LP + LA +
LM + LB), and at this time, it is possible to sufficiently secure the intake inertia action in the low rotation range such as when the engine is idle.
In addition, the volume of the intake chamber on the downstream side of the throttle valve 38 does not include the volume of the accommodation chamber 41, so that 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 is stabilized. it can. On the other hand, when the engine reaches the high speed region, the controller 47 drives the movable intake pipe 42 around the actuator shaft 44 via the DC motor 28, and moves the tip opening 422 of the movable intake pipe 42 to the shortest intake passage position P0.

In this case, the seal ring 46 can smoothly slide on the outer peripheral surface of the small diameter portion 433 of the first fixed intake pipe 43, and the rotation resistance at that time is relatively small, and the switching operation with good responsiveness can be performed. The substantial intake branch path length L _T of each cylinder of the engine in this high engine speed range is (LP + LA), which is maintained at the shortest length, and the intake pulsation operation at the maximum output of the engine can be secured, which contributes to the improvement of output. . FIG.
Reference numeral 0 indicates a variable intake system for an engine as a second embodiment of the present invention. The variable intake path length mechanism A1 used by the variable intake system for this engine is installed in the intake system of a four-cylinder engine (not shown). Here, although the intake system of only one cylinder is shown in FIG. 20, since the intake systems of the other cylinders have the same configuration, the intake system of only one cylinder will be mainly described below.

An intake pipe 52, an intake path length varying mechanism A1, and an intake manifold 53 are sequentially connected between the air cleaner 50 and an intake port 51 of an engine (not shown). A throttle valve 54 is provided in the intake manifold 53, and an intake path length varying mechanism A1 is provided upstream thereof. The intake passage length varying mechanism A1 includes a surge tank 55 and a curved first intake pipe 56 that communicates with through holes formed in upper and lower side walls of the surge tank 55.
A movable intake pipe 58 whose inner and outer wall surfaces are in sliding contact with the lower through hole 57 and the straight portion 561 of the first intake pipe 56;
8 of the intake manifold 53, which the funnel-shaped tip opening 581 of FIG.
And a movable intake pipe drive device 60 that is operated to approach and separate with respect to. A cylindrical seal 45 similar to that described with reference to FIGS. 14 to 18 is fitted to the inner peripheral wall of the distal end of the extending portion 59.

Here, the movable intake pipe drive device 60 is held by the control means (not shown) at the connection position Pa at the time of low rotation and is switched and held at the retracted position Pb at the time of high rotation.
When such a variable intake device of the engine is driven, the movable intake pipe 42 is held at the connection position Pa by the movable intake pipe drive device 60 in the low rotation range including the idle operation of the engine. In this case, the funnel-shaped tip opening 581 of the movable intake pipe 58 is in pressure contact with the tubular seal 45, and the inside of the surge tank 55 and the inside of the intake passage can be sealed. When intake air is introduced from the air cleaner 50 side, the intake pipe length in the intake passage length variable mechanism A1 can be maintained at Lm, and if the intake pipe lengths of the intake manifold 53 and the intake port 51 are set to Ln, The substantial intake branch path length L _T of each cylinder of
It can be secured as the longest pipe line consisting of (Ln + Lm). At this time, the tubular seal 45 can reliably prevent a short-circuit flow between the movable intake pipe 58 and the extending portion 59, and can sufficiently secure the intake inertia action in the low rotation range such as when the engine is idle and at the low rotation speed. The engine rotation in the range can be stabilized.

On the other hand, when the engine reaches the high speed region, the funnel-shaped tip opening 581 of the movable intake pipe 58 is switched and held at the retracted position Pb, and the substantial intake air branch of each cylinder of the engine in the high speed region. The path length L _T becomes (Ln), which is maintained at the shortest length, the intake pulse operation for the maximum output of the engine can be secured, and the output can be improved. As described above, according to the variable intake system for the engine of FIG. 1 to which the present invention is applied, the substantial intake branch path length L _T can be secured sufficiently long, and inertial supercharging is achieved by the action of the branch path part. The effect is sufficiently enhanced and the output can be improved in the low engine speed range. In particular, the casing members 39, 40 having the movable intake pipe 42 inside are fixed to the first fixed intake pipe 43 so that only the air that has passed through the air cleaner 37 and the second fixed intake pipe 33 is introduced into the first fixed intake pipe 43. The intake pipe 43 and the second fixed intake pipe 33 may be connected. In this case, the first fixed intake pipe 43
The inflow path of the intake air introduced into (1) does not largely change depending on the connection mode of the movable intake pipe 42, and the switching shock due to the switching of the movable intake pipe 42 can be eliminated.

In particular, either one of the downstream end portion of the second fixed intake pipe 33 or the upstream end portion of the movable intake pipe 42 may be provided with a cylindrical seal 45 that abuts on the other side. In this case, the sealability between the downstream end of the second fixed intake pipe and the upstream end of the movable intake pipe can be ensured, and the substantial intake branch path length can be prevented from becoming unstable due to the short-circuit flow. Rotational stability at low speeds can be secured. In particular, the end of the movable intake pipe 42 on the side of the second fixed intake pipe 33 is a funnel-shaped opening end 4.
21. A first lip 454 that extends in the axial direction and a second lip 455 that extends in the radial direction are formed at the end of the tubular seal 45 on the movable intake pipe side, and both the first and second lips are formed. It may be formed so as to contact the end of the movable intake pipe.

In this case, the first and second lips 454, 4
When 55 is brought into contact with the end of the movable intake pipe 42, the first lip 454 extending in the axial direction can be elastically displaced so as to be pressed into the funnel-shaped opening end 421 by receiving positive pressure in the intake passage, and the radial direction. The second lip 455 extending in the direction can be elastically displaced so as to be pressed against the funnel-shaped opening end 421 by receiving the positive pressure outside the intake passage. In any case, the second fixed intake pipe 33 and the movable intake pipe 42 have upstream ends. It is possible to secure the sealability between the parts. In particular, the first fixed intake pipe 43 and the movable intake pipe 42
May be formed on an arc having a common center point, and the movable intake pipe 42 may swing around the center point. 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.

[0038]

EFFECTS OF THE INVENTION A movable intake pipe that can be continuously moved between a longest intake passage position where the overlap length with the first fixed intake pipe is shortest and a shortest intake passage position where the overlap length is longest is provided. ,
When the movable intake pipe is at the longest intake passage position, the second fixed intake pipe is brought into close contact with the upstream end of the movable intake pipe,
The intake path length at this time can be ensured by the second fixed intake pipe having a tubular shape, the movable intake pipe, and the first fixed intake pipe communicating with the engine combustion chamber. Therefore, the substantial intake branch passage length can be secured sufficiently long, the effect of inertial supercharging is sufficiently enhanced by the action of the branch passage portion, and the output in the low engine speed region can be improved.

According to a sixth aspect of the present invention, a casing member isolated from the outside air is provided, and in the casing member, a fixed fixed intake pipe and a position connected to the end of the fixed intake pipe and the end thereof are connected. A movable intake pipe that is movable between the separated positions is provided, and the end portion of one intake pipe is formed in a funnel shape and a resin seal ring is arranged on the other intake pipe. The seal ring has a first lip extending in the axial direction and a second lip extending in the radial direction at the end on the movable port side, and the end of the movable port contacts the resinous seal ring. Therefore, when both the first and second lips contact the end of the movable port, the first lip extending in the axial direction can be elastically displaced so as to receive positive pressure in the intake passage and be pressed against the funnel-shaped end. The second lip extending in the radial direction can be elastically displaced so as to be pressed against the funnel-shaped end portion by receiving positive pressure outside the intake passage, and in any case, sealing performance between the fixed intake pipe and the movable intake pipe upstream end portion Can be ensured, the substantial intake branch path length can be prevented from becoming unstable due to the short-circuit flow, and rotational stability at low speed can be ensured.

[Brief description of the drawings]

FIG. 1 is a partially cutaway schematic side view of a variable intake system for an engine as an embodiment of the present invention.

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

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

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

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

FIG. 10 is a sectional view taken along line AA of FIG. 5;

FIG. 11 is a sectional view taken along line BB of FIG. 5;

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 an operation diagram of the bellows portion when switching the tubular seal of FIG. 14;

FIG. 16 is an operation explanatory diagram of the bellows portion after switching the tubular seal of FIG. 14;

FIG. 17 is a diagram for explaining the lip operation of the tubular seal of FIG. 14 when the intake passage has a negative pressure.

18 is an explanatory diagram of the lip operation of the tubular seal of FIG. 14 when the intake passage has a positive pressure.

19 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. 20 is a sectional view of an intake path length varying mechanism used by a variable intake system for an engine as another embodiment of the present invention.

FIG. 21 is a sectional view of a main part of a conventional variable intake system for an engine.

22 is an explanatory diagram of operating characteristics of the variable intake system in FIG.

FIG. 23 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 type casing 41 Storage chamber 42 Movable intake pipe 43 First fixed intake pipe 44 Actuator shaft 45 Cylindrical Seal 453 Bellows portion 454 First lip 455 Second lip 46 Seal ring A, A1 Intake pipe length variable mechanism R1 Fixed intake passage R2 Movable intake passage P0 Shortest intake passage position P1 Longest intake passage position L0 Intake manifold and intake passage Length LA 1st fixed intake pipe length LB 2nd fixed intake passage length LM Movable intake pipe length Ln Intake manifold and intake port intake passage length Lm Intake pipe length in variable intake passage length mechanism L _T Intake branch passage Long

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Kumagai 5-3-8 Shiba, Minato-ku, Tokyo, Mitsubishi Motors Corporation (72) Inventor Hirofumi Higashi 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 first fixed intake pipe communicating with an engine combustion chamber, and a first fixed intake pipe fitted to an upstream end of the first fixed intake pipe to form at least a part of an intake passage. A movable intake pipe that can continuously move between the longest intake passage position where the overlap length is the shortest and the shortest intake passage position where the overlap length is the longest, and the upstream end is the intake volume chamber or the atmosphere opening port. A variable intake system for an engine, comprising: a second fixed intake pipe which is communicated with the movable intake pipe and whose downstream end is in close contact with the upstream end of the movable intake pipe when the movable intake pipe is at the longest intake passage position. 2. The variable intake system for an engine according to claim 1, wherein an air purifying device is arranged upstream of the second fixed intake pipe, and the movable intake pipe is built in the inside of the second fixed intake device. The first fixed intake pipe and the second fixed intake pipe are arranged so that only the air passing through the intake pipe is introduced into the first fixed intake pipe.
A variable intake system for an engine, comprising a casing member for connecting a fixed intake pipe. 3. The variable intake system for an engine according to claim 1 or 2, wherein the movable intake pipe has the longest length at either one of the second fixed intake pipe downstream end or the movable intake pipe upstream end. A variable intake device for an engine, comprising a resin seal member (elastic member) arranged to come into contact with the other side when in the passage position. 4. The variable intake system for an engine according to claim 3, wherein the end of the movable intake pipe on the side of the second fixed intake pipe is formed in a funnel shape, and the end of the resin seal member on the side of the movable intake pipe is formed. A first lip extending in the axial direction and a second lip extending in the radial direction are formed at the end portions, and both the first and second lips are formed so as to contact the end portion of the movable intake pipe. Movable intake device for the engine. 5. The variable intake system for an engine according to claim 1, 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 A variable intake system for an engine, which swings about a center point. 6. A casing member isolated from the outside air is provided,
In the casing member, a fixed fixed intake pipe and a movable intake pipe movable between a position connected to the end of the fixed intake pipe and a position separated from the end are provided. The end portion of the intake pipe is formed in a funnel shape, and a resin seal ring is arranged on the other intake pipe, and the resin seal ring has a radius and a first lip extending in the axial direction at the end portion on the movable intake pipe side. A variable intake device for an engine, comprising a second lip extending in a direction, wherein an end of the movable intake pipe abuts on the resin seal ring.