JP2724750B2 - Intake device for multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of the Invention The present invention is to improve the volumetric efficiency of a multi-cylinder internal combustion engine by controlling intake pressure fluctuation in an intake system in the engine. The present invention relates to an improvement of an air intake device in which

(2) Conventional technology In a conventional intake device for a multi-cylinder internal combustion engine, intake pressure fluctuation between cylinders that does not cause intake interference resonates by variably controlling the length and volume of the intake system according to the operating state of the engine. The resonance effect, or the inertial effect utilizing the fact that a negative pressure wave generated at the start of intake in each cylinder is reflected by the volume expansion distribution chamber provided in the intake system and returned to the intake port side, thereby exhibiting an inertia effect from the low speed of the engine. Various intake devices have been already proposed to increase the volumetric efficiency up to a high-speed range (for example, see Japanese Patent Application Laid-Open No. 60-156930).

In the intake device, a distribution pipe connecting each of the cylinders and a volume expansion section provided in an intake system of a multi-cylinder internal combustion engine is provided so as to surround an outer periphery of the volume expansion section, and a middle portion and a volume of the distribution pipe are provided. The enlargement section can be short-circuited via a pipe length switching valve, so that the effective length of the distribution pipe can be switched between long and short. In the low-speed operation range of the engine, the effective length of the distribution pipe is increased to reduce the natural frequency of the intake system, and in the high-speed operation range, the effective length of the distribution pipe is reduced to reduce the natural vibration of the intake system. By increasing the number, the effect of inertia supercharging in a wide operating range of the engine is improved.

(3) Problems to be Solved by the Invention However, the conventional intake device for a multi-cylinder internal combustion engine switches the passage length in an inertial supercharging system between two stages, one for low speed and one for high speed. In order to prevent the torque in the medium speed operation range from decreasing, the valve timing is adjusted in conjunction with the opening / closing control of the pipe length switching valve. For this reason, not only does the structure of the intake system become complicated and large, the cost increases, but also the degree of freedom in laying out the engine in a narrow engine room decreases.

The present invention has been made in view of the above-described circumstances, and provides a compact and simple intake device capable of switching between a resonance supercharging system and an inertia supercharging system and switching an effective pipe length. Aim.

B. Configuration of the Invention (1) Means for Solving the Problems According to the present invention, in order to achieve the above object, the inside of the volume expansion section is partitioned into a pair of resonance chambers, and each resonance chamber has its upstream side open to the outside air. And a plurality of distribution pipes connecting the downstream side thereof to a group of cylinders whose intake strokes are not continuous with each other, and further communicates the two resonance chambers with each other in accordance with the operating state of the engine. Or an intake device for a multi-cylinder internal combustion engine provided with an on-off valve configured to shut off the air, wherein the distribution pipe is disposed so as to surround an outer periphery of the volume expansion section, and the distribution pipe is in contact with the volume expansion section. A pipe length switching valve is provided at an intermediate portion of the pipe, and the intermediate portion of the distribution pipe is short-circuited to the volume expansion section by opening control of the pipe length switching valve.

(2) Operation According to the above feature, by closing both the on-off valve and the pipe length switching valve, communication between the left and right resonance chambers formed in the volume expansion section and communication between the volume expansion section and the distribution pipe are achieved. The two systems are shut off to form a two-system resonance supercharging system, and the volume efficiency in the low-speed operation range of the engine is improved. When the on-off valve is controlled to open, the left and right resonance chambers communicate with each other, thereby canceling the two resonance supercharging systems and newly forming an inertial supercharging system. Volumetric efficiency is improved. Further, when both the on-off valve and the pipe length switching valve are controlled to open, the middle part of the distribution pipe is short-circuited to the volume expansion part, the effective length of which is reduced, and the volume efficiency in the high-speed operation range of the engine is improved.

Each distribution pipe is disposed so as to surround the outer periphery of the volume expansion section connected to the upstream side thereof, and furthermore, since a pipe length switching valve is provided at an intermediate portion of the distribution pipe contacting this volume expansion section, The volume expansion section and the distribution pipe are rationally integrated, and the intake system can be formed compact.

(3) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 6 show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a V-type six-cylinder internal combustion engine equipped with the device of the present invention, and FIG. 2 is a plan view of a cylinder block thereof. , FIG. 3,
FIG. 1 is an enlarged partial plan view along the line III-III, FIG. 4 is an enlarged partial plan view along the line IV-IV in FIG. 1, FIG. 5 is a cross-sectional view along the line VV in FIG. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG.

1 and 2, an engine body E of the six-cylinder internal combustion engine is shown.
Has a pair of left and right engine blocks Bl, Br arranged in a V-shape with each other, and the left and right engine blocks Bl, Br are respectively joined to the cylinder blocks 11l, 1r and the deck surface thereof. The left cylinder block 11 has three left cylinders 3l # formed in series, and the right cylinder block 1r also has three cylinders 3r # formed in series. The three left cylinders 3l # constitute a left cylinder group Cl in which the intake strokes do not continue, that is, the intake valves 10 do not overlap, and the three right cylinders 3r # also have no consecutive intake strokes, that is, the intake valves described later. 10 constitute the right cylinder group Cr that does not overlap.

Pistons 4 are slidably fitted to the left and right cylinders 3l, 3r, respectively, as usual, and these pistons 4 are interlocked with a crankshaft 6 via connecting rods 5.
A combustion chamber 7 facing the piston 4 and intake and exhaust ports 8 and 9 communicating with the combustion chamber 7 are formed in the left and right cylinder heads 21 and 2r, respectively. An intake valve 10 that opens and closes 8 is provided, and each exhaust port 9 is provided with an exhaust valve 11 that opens and closes the port 9. And intake and exhaust valves 10,11
Is opened and closed by a conventionally known valve mechanism 12 at a predetermined timing.

A plurality of intake ports 8 # of the left and right cylinder heads 2l, 2r are connected to an intake system In, which will be described in detail later.
A conventionally known exhaust system (not shown) is connected to the plurality of exhaust ports 9 # of the right cylinder heads 21 and 2r.

Next, the configuration of the intake system In will be described in detail with reference to FIGS. 2 to 6. The intake system In is disposed in the V space C between the left and right engine blocks 11 and 1r, and the air cleaner Ac is provided.
And an intake passage Pi connected to an outlet of the air cleaner Ac.
And a box-shaped volume expansion portion Bg having a pair of left and right resonance chambers Cr-1 and Cr-r connected to the downstream end of the intake passage Pi, and integrally formed on the outer periphery of the volume expansion portion Bg. The left and right resonance chambers Cr are joined to end faces of the left and right cylinder blocks 11l and 1r where the intake ports 8 # are opened.
-L, Cr-r, and an intake manifold Mi that communicates the left and right cylinder groups Cl, Cr, respectively.

The intake passage Pi is provided with an air cleaner as shown in FIG.
A downstream intake passage 16 is integrally connected to a downstream end of the upstream intake passage 14 connected to Ac via a throttle body 15. The upstream intake passage 14 is formed in a hollow cylindrical shape to take in the intake air from the air cleaner Ac, and the throttle body 15 has bolts 17 ‥ and 18 at its axial ends at the upstream intake passage 14 and the downstream intake passage 16 respectively. Throttle valve 20 fixed by ‥ and controlled to open and close by operation unit 19 inside
Is provided.

The downstream side intake passage 16 has a rectangular cross section and extends along the direction of the crankshaft 6 of the engine. The inside of the downstream intake passage 16 is divided into left and right branch resonance passages 22l, 22
It is divided into r. On the left and right sides of the downstream ends of the left and right branch resonance passages 22l and 22r, the resonance chambers Cr-1 and Cr-r are provided.
The left and right communication ports 33l, 33r are respectively opened to communicate with each other, and the open / close valve 23 is provided between the communication ports 33l, 33r. That is, the partition 21 has left and right resonance chambers Cr-l,
A valve holder 25 having an opening 24 communicating with Cr-r is provided, and a valve shaft 26 extending in the axial direction of the downstream intake passage 16 is rotatably supported on the valve holder 25. Valve shaft 26
In addition, a rectangular plate-shaped valve body 27 for opening and closing the valve port 24 is provided with a screw 28.
It is fixed with. One end of the valve shaft 26 is a valve holder 25
Projecting out of the downstream intake passage 16 through the end wall of
A conventionally known actuator 29 is connected to the protruding end. The operation of the actuator 29 is controlled in accordance with the operating state of the engine, and the opening and closing of the on-off valve 23 is controlled. At times, the opening / closing valve 23 is controlled to open.

Therefore, when the on-off valve 23 is closed, the left and right branch resonance passages 22l, 22r communicate with the left and right resonance chambers Cr-l, Cr-r independently via the communication ports 33l, 33r, respectively. Two resonance supercharging systems are configured. When the on-off valve 23 is opened, the left and right resonance chambers Cr-1, Cr-r communicate with each other through the valve port 24 and the left and right communication ports 33l, 33r,
In FIGS. 3 and 5, a large-volume inertial supercharging distribution chamber Ch indicated by a two-dot chain line and a diagonal line is formed, and one system of inertia supercharging intake system is formed.

As shown in 1,5 figures, intermediate casing 31 ₁ of volume expanding portion Bg the downstream side intake passage 16 is formed integrally with the upper and lower surfaces open, and the upper casing ₃₁₂ of the lower surface opening positioned above and below by overlapping three members of the lower casing ₃₁₃ of the open top are configured by combining a plurality of bolts 32 ‥.

Inside the volume expansion portion Bg, left and right resonance chambers Cr-1 and Cr-r communicating with the left and right branch resonance passages 22l and 22r of the downstream side intake passage 16 respectively are provided with the three casings 31. _1, 31 is formed over _2, 31 _3. Left, right resonance chamber Cr-l, the Cr-r, the intermediate casing 31 ₁ and the left, respectively forming the three oblong in the coupling portion of the lower casing _313, the right exhaust ports 34l ‥, is 34r ‥ provided (See FIG. 3). And left resonance chamber Cr-1
The three discharge ports 34l ‥ of the outer circumference of the volume expansion portion Bg are approximately 360
Three distribution pipes 35 formed to surround over ゜
₁ , 35 ₃ and 35 ₅ communicate with the three cylinders 3l in which the intake order of the left cylinder block 1l is not continuous, and the three discharge ports 34r # of the right resonance chamber Cr-r share the same outer circumference of the volume expansion portion Bg. communicates with the three cylinders 3r intake order of the right cylinder block 1r is not continuous with the other 3 distributing pipes 35 _2, 35 _4, 35 ₆ formed to surround substantially over 360 °. That is, the intake manifold Mi consisting six distributing pipes 35 ₁ to 35 ₆ disposed to wind around in opposite directions alternately in every other are formed integrally on the outer periphery of the volume expanding portion Bg, therein The pair of resonance chambers Cr
−l, Cr−r are positioned so as to be surrounded.

As shown in FIG. 4 to FIG. 6, the above first to sixth distribution pipes
35 _{1-35 6} and the left and right resonance chambers Cr-l, the boundary between the Cr-r right butterfly type pipe length switching valve 38l, 38r is provided. That is, the intermediate portion of the right resonance chamber Cr-r from the lower casing 31 ₃ and of the intermediate casing 31 three extending through _a distribution tube 35 _2, 35 _4, 35 _6, valve port formed in the upper casing 31 ₂ 39 _2, 39 _4, 39 of the left side ₆ through the resonance chamber C
rl and the left resonance chamber Cr
Distributor pipe 35 ₁ of the three extending through the lower casing 31 ₃ and the intermediate casing 31 from ₁ -l, 35 _3, 35 middle part of the ₅ valve ports 39 ₁ formed in the upper casing 31 _2, 39 _3, 39 ₅ Through the upper portion of the right resonance chamber Cr-r.

Rotatably supported pipe length switching valve 38l through the upper casing _312, a pair of left and right valve shaft 40l of 38r, 40r includes three valve ports 39 ₂ of the left side, respectively, 39 _4, 39 ₆ and right 3 valve openings 3
9 ₁ , 39 ₃ , 39 ₅ Cross the center of ₅ and at that position each valve port 39
The valve body 41 _{1-41 6} for opening and closing the _{1-39 6} is secured with a screw 42. Ryobenjiku 40 l, end which projects from the upper casing 31 _{and second} 40r is connected to the actuator 43 by pipe length switching valve 38l, 38r
For example, the pipe length switching valves 38l and 38r are controlled to be closed below the medium speed rotation range of the engine, and the pipe length is controlled in a high speed rotation range where the opening and closing valve 23 is controlled to be opened. The switching valves 38l, 38r are controlled to open. When the pair of pipe length switching valves 38l and 38r are controlled to open,
Each intermediate portion of the distribution pipe 35 _{1-35 6} pipe length switching as effective length of the distribution pipe 35 _{1-35 6} communicates with a common inertial supercharging distribution chamber Ch is reduced is performed.

Each fuel injection nozzle 44 in the upper wall of the downstream end of the first to sixth of the pipe 35 ₁ to 35 ₆ ‥ is provided as shown in Figure 1.

 Next, the operation of the embodiment of the present invention will be described.

Two actuators 29, 43 according to the operating state of the engine
For example, in the low-speed operation state, both the on-off valve 23 and the left and right pipe length switching valves 38l, 38r are controlled to close as shown in FIG. Then left and right resonance chambers Cr-1 and Cr
-R is disconnected from each other, the branch resonance passages 22l and 22r for each cylinder group as the intake system, and the left and right resonance chambers C for each cylinder group.
r−l, Cr−r and left and right distribution pipes 35 ₁ , 35 ₂ , 35 ₃ , 3
Two intake systems consisting of 5 ₄ , 35 ₅ , and 35 ₆ , that is, two resonance supercharging systems that do not cause intake interference from the three cylinders 3 l ‥ and 3 r 上流 to the upstream of the intake passage Pi are configured. Moreover, this resonance supercharging system has a relatively long passage length, and its natural frequency can be made substantially coincident with the opening / closing cycle of each intake valve 10 ° in the low-speed rotation range of the engine, so that the resonance supercharging effect is effective. To increase the volumetric efficiency in the low-speed rotation range of the engine.

When the engine is in the medium speed operation state, the on-off valve 23 is controlled to open as shown by the chain line in FIG. 5, and the left and right resonance chambers Cr-1,
Cr-r communicates with each other to form a large-volume inertial supercharging distribution chamber Ch shown by a two-dot chain line in FIG. 5, and the chamber Ch is shared by the left and right cylinders 3l ‥ and 3r ‥. Communicated. In this state, the two resonance supercharging systems are cancelled, the negative pressure wave generated in the engine intake stroke is reflected and inverted by the large-volume inertial supercharging distribution chamber Ch, and the positive pressure waves are converted into the respective cylinders 3l ‥, 3r. The inertia supercharging system is constituted by being propagated to the intake port 8 of ‥, and the length of the passage through which the negative pressure wave and the positive pressure wave propagate is shortened. The volume efficiency in the medium speed operation range is increased in accordance with the opening / closing cycle of 高 め.

Further, when the engine reaches a high-speed operation state, the pipe length switching valve 38 is further increased.
l, 38r is in the valve opening control as shown in FIG. 5 chain lines, the distribution pipe 35 ₁ which extends from the resonance chamber Cr-l, 35 _3, 35 ₅ of the intermediate portion is the inertia supercharging via a pipe length changeover valve 38r Distribution chamber Ch
Both shorted to the intermediate portion of the distribution pipe 35 _2, 35 _4, 35 ₆ extending from the resonant chamber Cr-r is shorted to the inertia supercharging distribution chamber Ch via a pipe length changeover valve 38l. Therefore, the inertial supercharging distribution chamber Ch and the left and right cylinder groups Cl and Cr are connected to the distribution pipe 35 _1.
35 ₆ is the shortest the valve ports 39 ₁ to 39 ₆ is connected via a downstream portion than in passage length of, and will be larger inertial supercharging system natural frequency is configured, the intake pressure cycle Can be matched with the opening / closing cycle of the intake valve 10 at the time of high-speed operation of the engine, and the volumetric efficiency in the operating region can be increased.

The left as the volume expanding portion of the intermediate portion of each distribution tube 35 _{1-35 6} for the pipe length switching in the high speed operating range are communicated,
Since the right resonance chambers Cr-1 and Cr-r (that is, the tube length switching chamber Ch) are used, it is not necessary to provide a specially enlarged volume for the tube length switching, and the dimensions of the intake system are made compact. It becomes possible. In addition, distribution pipe 35
_{1-35 6} left, right resonance chamber Cr-l, is disposed so as to surround the outer periphery of the Cr-r, the resonance chamber Cr-l, Cr
Pipe length switching valve 38l in the middle portion of the distributor pipe 35 _{1-35 6} in contact with -r,
Since the 38r is provided, the entire intake system is formed more compactly.

As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various small design changes can be made without departing from the present invention described in the claims. Is possible.

For example, instead of connecting the middle part of the distribution pipe extending from one resonance chamber to the other resonance chamber, it may be connected to the resonance chamber on the same side.

C. Effects of the Invention As described above, according to the present invention, a volume expansion section is provided that forms a pair of resonance chambers that can communicate with each other by an on-off valve, and a distribution pipe that connects the volume expansion section to each cylinder is provided. It is arranged so as to surround the outer periphery of the volume expansion section, and the middle part of the distribution pipe can be short-circuited to the volume expansion section by the pipe length switching valve, so that it is possible to switch between the resonance supercharging system and the inertia supercharging system. Not only that, the effective pipe length of the inertial supercharging system can be further switched to two stages. Therefore, high volumetric efficiency can be obtained in all operating ranges of the engine at low, medium, and high speeds. In addition, the volume expansion portion and the distribution pipe are rationally integrated, and the opening / closing valve and the pipe length switching valve are provided in the volume expansion portion. , It is possible to increase the degree of freedom of the layout of the internal combustion engine with respect to.

[Brief description of the drawings]

1 to 6 show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a V-type six-cylinder internal combustion engine equipped with the device of the present invention, and FIG. 2 is a plan view of a cylinder block thereof. FIG. 3 is an enlarged partial plan view along the line III-III in FIG. 1, FIG. 4 is an enlarged partial plan view along the line IV-IV in FIG. 1, and FIG. 5 is a line VV in FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. Bg: Volume expansion part, Cr-1, Cr-r: Left and right resonance chambers, Cl, Cr: Cylinder groups 22l, 22r: Resonance tubes, 23: On-off valve, 35 _{1 to} 35 ₆ ... Distribution pipe, 38l, 38r …… Pipe length switching valve

Claims (1)

(57) [Claims] The interior of a volume expansion section (Bg) is partitioned into a pair of resonance chambers (Cr-1, Cr-r), and each of the resonance chambers (Cr-1, Cr-r) is partitioned.
-R) is a resonance tube (221, 22) communicating with the outside air on the upstream side.
r), a cylinder group (Cl,
Communicating with the plurality of distribution pipes (35 ₁ to 35 ₆₎ connected to Cr), and more the volume expanding portion (Bg), in response to said operating state of the engine both resonance chambers (Cr-l, Cr-r ) Communicate with each other,
Or in the intake system of a multi-cylinder internal combustion engine Blocked way opening and closing valve (23) is provided, said distribution pipe (35 ₁ to 35 ₆₎ is arranged as surrounding an outer periphery of the volume expanding portion (Bg) with, pipe length changeover valve in an intermediate portion (38l, 38r) is provided in the volume expanding portion and the distribution pipe in contact with the _{(Bg) (35 1 ~35 6} ), tube length switching valve (38l, 38
said distribution pipe by opening control r) (35 ₁ ~35 ₆₎
An intake device for a multi-cylinder internal combustion engine, wherein an intermediate portion of the internal combustion engine is short-circuited to the volume expansion portion (Bg).