JPH0337325A - Intake device for multicylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain the high volume efficiency in all the speed operation region of an engine by arranging a distribution pipe for connecting a spread capacity part and each cylinder so as to surround the outer periphery of the spread capacity part and permitting the intermediate part of the distribution pipe to be short circuited with the spread capacity part by a pipe length selecting valve. CONSTITUTION:The inside of a spread capacity part Bg in an intake system In is divided into a pair of resonance chambers Cr-l and Cr-r. The resonance chambers Cr-l and Cr-r communicate to a pair of resonance pipes 22l and 22r whose upstream sides communicate to the outside air, and the downstream sides communicate to a plurality of distribution pipes 351 - 356 connected with a pair of cylinder groups in which each suction cycle is not continuous. further, an opening/closing valve 23 which connects and disconnects the resonance chambers Cr-l and Cr-r according to the engine operation state is arranged in the spread capacity part Bg. In this device, each intermediate part of the distribution pipes 351 - 356 which are arranged so as to surround the outer periphery of the spread capacity part Bg is short-circuited by opening a pipe length selecting valve not shown on the figure.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention is directed to improving the volumetric efficiency of a multi-cylinder internal combustion engine by controlling intake pressure fluctuations within the intake system. The present invention relates to an improvement of an intake device.

(2) Conventional technology Conventionally, in the intake system of a multi-cylinder internal combustion engine, the length and volume of the intake system are variably controlled according to the operating state of the engine, so that intake pressure fluctuations between cylinders resonate without causing intake interference. The resonance effect, or the inertia effect that takes advantage of the fact that the negative pressure waves that occur at the start of intake in each cylinder are reflected by the volume expansion distribution chamber provided in the intake system and returned to the intake port side, is used to reduce engine speed from low speeds. Various intake devices have already been proposed that increase volumetric efficiency up to high speed ranges (see, for example, Japanese Patent Laid-Open No. 156930/1983).

In the above-mentioned intake system, a distribution pipe connecting a volume expansion part provided in an intake system of a multi-cylinder internal combustion engine and each cylinder is arranged so as to surround the outer periphery of the volume expansion part, and an intermediate part of the distribution pipe connects a volume expansion part to each cylinder. The expanded portion can be short-circuited via a pipe length switching valve, thereby making it possible to switch the effective length of the distribution pipe to a longer or shorter length. Then, in the low-speed operating 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 operating range, the effective length of the distribution pipe is decreased to reduce the natural frequency of the intake system. The number of engines has been increased to improve the inertial supercharging effect over a wide range of engine operation.

(3) Problems to be Solved by the Invention However, the conventional intake system for the multi-cylinder internal combustion engine described above switches the passage length in the inertial supercharging system into two stages, one for low speed and one for high speed. Torque decreases in the medium-speed operating range, and to prevent this, valve timing is adjusted in conjunction with the opening/closing control of the pipe length switching valve.

This not only makes the structure of the intake system more complicated and larger, increasing costs, but also reduces the degree of freedom in layout of the engine in a narrow engine room.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an intake device that is compact and has a simple structure, which is capable of switching between a resonant supercharging system and an inertial supercharging system, and switching the effective pipe length. purpose.

B0 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 part is divided into a pair of resonance chambers, and each resonance chamber has the following features:
Its upstream side is connected to a resonance pipe that communicates with the outside air, and its downstream side is connected to a plurality of distribution pipes that connect to cylinder groups whose intake strokes are not consecutive. In an intake system for a multi-cylinder internal combustion engine that is provided with an on-off valve that communicates or blocks resonance chambers with each other, the distribution pipe is arranged so as to surround the outer periphery of the volume expansion part, and the volume expansion part A pipe length 5 switching valve is provided at an intermediate portion of the distribution pipe that is in contact with the pipe, and the intermediate portion of the distribution pipe is short-circuited to the volume expansion portion by controlling the opening of the pipe length switching valve.

(2) Effect According to the above feature, by controlling both the on-off valve and the pipe length switching valve to close, the left and right resonance chambers formed in the volume expansion part communicate with each other and the volume expansion part and the distribution pipe communicate with each other. is shut off, forming a two-system resonant supercharging system, improving volumetric efficiency in the low-speed operating range of the engine. When the on-off valve is opened, the left and right resonance chambers communicate with each other, canceling the two resonance supercharging systems and creating a new inertial supercharging system, which allows the engine to operate at medium speed. The volumetric efficiency in the area is improved. Furthermore, 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, its effective length is reduced, and the volumetric efficiency in the high-speed operating range of the engine is improved.

Each distribution pipe is arranged so as to surround the outer periphery of the volume expansion part connected to the upstream side thereof, and a pipe length switching valve is provided in the middle part of the distribution pipe in contact with the volume expansion part. The volume expansion part and the distribution pipe are rationally integrated, making it possible to form the intake system compactly.

(3) Examples Hereinafter, the present invention will be explained in detail with reference to the drawings.

Figures 1 to 6 show an embodiment of the present invention. Figure 1 is a vertical sectional view of the main part of a type 6-cylinder internal combustion engine equipped with the device of the present invention, and Figure 2 is a plan view of its cylinder block. , Figure 3 is
Fig. 1 is an enlarged partial plan view taken along the line m-m;
An enlarged partial plan view taken along the line IV-IV, FIG.
A sectional view taken along the line V-V in Figure 6, and Figure 5 Vl-Vl.
It is a sectional view along a line.

In Figure 1.2, the engine body E of the six-cylinder internal combustion engine
are a pair of lefts arranged in a figure 7 shape with respect to each other.

Right engine block Bj! , Br, left and right engine blocks BI1. ．． Br is the cylinder block IL1r and the cylinder head 2j connected to the deck surface thereof, respectively! , 2r, and the left cylinder block II! ,
Three left cylinders 31... are formed in series in the right cylinder block 1r, and three cylinders 3r... are formed in series in the right cylinder block 1r. The three cylinders w31 on the left side constitute the left cylinder group C2 whose intake strokes are not continuous, that is, the intake valves 10 do not overlap, and the three cylinders 3r on the right side also have non-successive intake strokes, that is, as will be described later. The intake valves 10 constitute a right-hand cylinder group C'' in which the intake valves 10 do not overlap.

Said left cylinder 3I! . . 3r . . . , pistons 4 are slidably fitted as usual, and these pistons 4 are interlocked with a crankshaft 6 via a connecting rod 5. In addition, the left and right cylinder heads 2l and 2r include
A combustion chamber 7 facing the piston 4 and a suction communicating with the combustion chamber 7, respectively.

Exhaust boats 8.9 are formed, each intake boat 8 is provided with an intake valve 10 that opens and closes the boat 8, and each exhaust boat 9 is provided with an exhaust valve 1 that opens and closes the boat 9.
1 are provided respectively. And intake and exhaust valves 10.11
is opened and closed at predetermined timing by a conventionally known valve operating mechanism 12.

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

Next, the configuration of the intake system In will be explained in detail with reference to FIGS. 2 to 6. This intake system In is located at the left side.

Right engine block 11. An air cleaner Ac, an intake passage Pi connected to the outlet of the air cleaner Ac, and a pair of left and right resonance chambers Cr- connected to the downstream end of the intake passage N1pt are arranged in the V space C between lr. l,C
A box-shaped volume expansion part B having rr, and the left and right cylinder blocks 1j, which are integrally formed on the outer periphery of this volume expansion part Bg! , lr, the left and right resonance chambers Cr-
1! .

Cr-r, and an intake manifold Mi that communicates with the left and right cylinder groups Cl and Cr, respectively.

As shown in FIG. 3, the intake passage pt is constructed by integrally connecting a downstream intake passage 16 via a throttle body 15 to the downstream end of an upstream intake passage 14 connected to the air cleaner Ac. Passage 14 is air cleaner Ac
The throttle body 15 is formed into a hollow cylindrical shape in order to draw intake air from the air, and the throttle body 15 has both ends in the axial direction connected to the upstream intake passage 14 and the downstream intake passage 16 with bolts 17 and 16, respectively.
. . , and a throttle valve 20 whose opening/closing is controlled by an operating section 19 is provided inside the throttle valve 20 .

The downstream intake passages 16 have a rectangular cross section and extend along the direction of the crankshaft 6 of the engine, and their interiors are parallel to each other by a partition wall 21.

Right branch resonance passage 221. It is divided into 22 r.

On both left and right sides of the downstream ends of the left and right branch resonance passages 22l and 22r, the resonance chambers Cr-7! , Cr-r are opened, and an on-off valve 23 is provided between the communication holes 33f and 33r. That is, the partition wall 21 is provided with a valve holder 25 in which a valve port 24 that communicates with the left and right resonance chambers Cr-l and Cr''r is opened. A valve shaft 26 extending along the valve shaft 26 is movably supported, and a rectangular plate-shaped valve body 27 for opening and closing the valve port 24 is fixed to the valve shaft 26 with screws 28.One end of the valve shaft 26 penetrates the end wall of the valve holder 25 and projects out of the downstream intake passage 16, and a conventionally known actuator 29 is connected to the projecting end. The operation is controlled to open and close the on-off valve 23. For example, when the engine is running at low speed, the on-off valve 23 is closed, and when the engine is running at medium or high speed, the on-off valve 23 is opened.

Therefore, when the on-off valve 23 is closed, the left side.

The right branch resonance passages 22ffi and 22r are connected to the left and right resonance chambers Cr-l via the communication holes 33l and 33r, respectively.
, Cr-r, to form a two-system resonance supercharging system. Further, when the on-off valve 23 is opened, the left and right resonance chambers Cr-l and Cr-r communicate with each other via the valve port 24 and the left and right communication holes 332.33r, and the third
In the figure and FIG. 5, an inertial supercharging distribution chamber ch having a large volume shown by two dots, one line, and hatching is constructed to constitute one system of inertial supercharging intake system.

As shown in FIG. 1.5, the volume expansion portion Bg includes an intermediate casing 3L1 with an open upper and lower surface in which the downstream intake passage 16 is integrally formed, and an upper casing 31. and lower casing 31s with open top surface
It is constructed by overlapping three members and connecting them with a plurality of bolts 32.

Inside the volume expansion part BH, there are left and right resonance chambers Cr-1 and Cr-r, which communicate with the downstream of the left and right branch resonance passages 22l and 22r of the downstream side intake passage 16, respectively.
It is formed over three casings 31t, 31g, and 31s. The left and right resonance chambers Cr-l and Cr-r include the intermediate casing 311 and the lower casing 313.
The left and right discharge boats 34j each have three elliptical shapes at the joints! ..., 34r... are provided (see Figure 3), and 3 of the left resonance chamber Cr-1.
The three discharge boats 34L... are formed so as to surround the outer periphery of the volume expansion part Bg over approximately 360 degrees, and the intake order of the left cylinder block 11 is not consecutive due to the three distribution pipes 35+, 35s, and 35s. 3
1 and the right resonance chamber Cr-r.
The intake order of the right cylinder block 1r is not continuous due to the other three distribution pipes 35x, 35m, 35&, which are also formed to surround the outer periphery of the volume expansion part Bg over approximately 360°. It communicates with two cylinders 3r. That is, an intake manifold Mi consisting of six distribution pipes 356 to 35h arranged so as to wrap around every other pipe in opposite directions is integrally formed on the outer periphery of the volume expansion part Bg, and the above-mentioned A pair of resonance chambers Cr-j! , Cr-r are located so as to be surrounded.

As shown in Fig. 4 to Fig. 6, the above-mentioned first to sixth distribution pipes 3
51-35 & left and right resonance chambers Cr-l, Cr-
Right and left butterfly-type pipe length switching valves 38 are installed at the boundary with r.
1.38r is provided. That is, from the right resonance chamber Cr-r to the lower casing 31. and three distribution pipes 35l, 354, extending through the intermediate casing 311.
The middle part of 356 has valve ports 3L, 39. formed in the wood of the upper casing 31. ．． 39. via the left resonance chamber C
r-j! from the left resonance chamber Cr-1 to the upper part of the lower casing 31. and three distribution pipes 356,353 extending through the intermediate casing 311,
The middle part of 355 is a valve port 39 formed in the upper casing 31g. ．． 393°39, right resonance chamber C
It communicates with the upper part of rr.

A pair of left and right valve shafts 40l, 4 of pipe length switching valves 38l, 38r are rotatably supported through the upper casing 31t.
0r are the three valve ports 39l and 39.0r on the left side, respectively. ．． 3
94 and the three valve ports 39 on the right side. 393.39s, and at that position each valve port 391-39. Valve bodies 411-41. The end of the valve shaft 401.4Or, which is fixed with a screw 42, protruding from the upper casing 31 is connected to an actuator 43 to control the opening and closing of the pipe length switching valves 38Il and 38r.
For example, below the medium speed rotation range of the engine, the pipe length switching valve 38L
38r is controlled to close and the on-off valve 23 is controlled to open.
1 and 38r are controlled to open. Then, when the pair of pipe length switching valves 381 and 38r are controlled to open, each distribution pipe 35
1 to 35, the middle part is a common inertial supercharging distribution chamber ch
Pipe length switching is performed so that the effective lengths of the distribution pipes 351 to 356 are reduced.

As shown in FIG. 1, fuel injection nozzles 44 are provided on the earth walls at the downstream ends of the first to sixth distribution pipes 351 to 35, respectively.

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

Two actuators 29.4 depending on the operating state of the engine
3 is actuated and, for example, in its low-speed operating state, the fifth
As shown in the figure, the on-off valve 23 and the left and right pipe length switching valves 38N,
38r are both controlled to close. Then, communication between the left and right resonance chambers Cr-l and Cr-r is cut off, and the intake system includes branch resonance passages 22N and 22r for each cylinder group, and a left resonance chamber for each cylinder group.

Right resonance chambers Cr-l, Cr-r, left cylinder group-specific,
Right distribution pipe 351.35! , 353.35°35s, 35
Two intake systems consisting of 6, i.e. 3 cylinders each
I1. ..., 3r... to the upstream of the intake passage Pi, two resonant supercharging systems are constructed in which there is no intake air interference, and this resonant supercharging system has a relatively long passage length and its natural frequency. can be made to substantially match the opening/closing period of each intake valve 10 in the low speed rotation range of the engine, and the resonance supercharging effect can be effectively exerted, thereby increasing the volumetric efficiency in the low speed rotation range of the engine.

When the engine is in a medium speed operating 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 and Cr-r communicate with each other to form a large volume inertial supercharging distribution chamber ch shown by diagonal double-dashed lines in FIG. are commonly communicated with. In this state, the two resonant supercharging systems are cancelled, and the negative pressure wave generated during the engine intake stroke is reflected by the large volume inertial supercharging distribution chamber channel.
This is reversed and the positive pressure waves are propagated to the intake boats 8 of each cylinder 31..., 3r... to form an inertial supercharging system, and the length of the passage through which the negative pressure waves and positive pressure waves propagate is shortened. Intake valve 10 when the intake pressure cycle is medium speed engine operation...
The volumetric efficiency in the medium speed operating range is increased in accordance with the opening/closing period.

Furthermore, when the engine reaches high-speed operation, the pipe length switching valve 38
C38r is controlled to open as shown by the chain line in FIG. 5, and the distribution pipe 351.356s extends from the resonance chamber Cr-1.
+ 35s is short-circuited to the inertial supercharging distribution chamber Ch via the pipe length switching valve 3.8r, and the distribution pipe a5s, 356, 3 extends from the resonance chamber Cr-r.
56 is short-circuited to the inertial supercharging distribution chamber ch via a pipe length switching valve 381. Therefore, the inertial supercharging distribution chamber ch and the left and right cylinder groups Cl, Cr are connected to the valve ports 39. of the distribution pipes 3Fz to 356. ~396 is connected via the downstream part to form an inertial supercharging system with the shortest passage length and large natural frequency, and the intake pressure cycle is changed to the intake valve 10 during high-speed operation of the engine. The volumetric efficiency in the operating range can be increased by matching the opening/closing period of the opening/closing period.

In the high-speed operation range, the left and right resonance chambers Cr-l and Cr-r (i.e., pipe length switching chamber Ch) are used as volume expansion parts in which the intermediate portions of the distribution pipes 356 to 356 communicate with each other in order to switch the pipe length. Therefore, there is no need to provide a special volume expansion section for switching the pipe length, and the intake system can be made compact in size. In addition, the distribution pipes 351 to 356 are connected to the left and right resonance chambers Cr-
1. It is arranged so as to surround the outer periphery of Cr-r,
This resonance chamber Cr-j! , Pipe length switching valves 3Bl and 38 are installed in the middle of distribution pipes 35+ to 35 in contact with Cr-r.
Since r is provided, the entire intake system can be formed more compactly.

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

For example, instead of communicating the middle portion of a distribution pipe extending from one resonance chamber with the other resonance chamber, it may communicate with the resonance chambers on the same side.

C0 Effects of the Invention As described above, according to the present invention, the volume expansion section is provided with a pair of resonance chambers that can be communicated with each other by an on-off valve, and the distribution pipes connecting the volume expansion section and each cylinder are connected to the above-mentioned distribution pipes. It is arranged so as to surround the outer periphery of the volume expansion part, and the middle part of this distribution pipe can be short-circuited to the volume expansion part using a pipe length switching valve, making it possible to switch between the resonant supercharging system and the inertial supercharging system. In addition, the effective pipe length of the inertial supercharging system can be further switched into two stages.

Therefore, it is possible to obtain high volumetric efficiency in all operating ranges of low speed, medium speed, and high speed of the engine. Moreover, the volume expansion section and the distribution pipe are rationally integrated, and the on-off valve and pipe length switching valve are provided in this volume expansion section, so the overall dimensions of the intake system can be made extremely compact, allowing for tight spaces. It becomes possible to increase the degree of freedom in the layout of the internal combustion engine.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention, in which FIG. 1 is a vertical cross-sectional view of a main part of a V-type 6-cylinder internal combustion engine equipped with the device of the present invention, and FIG. 2 is a plan view of its cylinder block. , Fig. 3 is an enlarged partial plan view taken along line ■-■ in Fig. 1, Fig. 4 is an enlarged partial plan view taken along line IV-IV in Fig. 1, and Fig. 5 is an enlarged partial plan view taken along line v-v in Fig. 4. FIG. 6 is a cross-sectional view taken along the line ■--■ in FIG. Bg...Volume expansion part, Cr-l, Cr-r...Left.

Claims (1)

[Claims] A pair of resonance chambers (Cr-
Cr-l, Cr-r), and each resonance chamber (Cr-l, Cr-r).
Cr-r) is a resonance pipe (22) whose upstream side communicates with the outside air.
1, 22r), and a plurality of distribution pipes (35_1
~35_6), and further communicates with the volume expansion part (Bg)
In this case, both resonance chambers (C
r-l, Cr-r) In an intake system for a multi-cylinder internal combustion engine that is provided with on-off valves (23) that communicate or block each other, the distribution pipes (35_1 to 35_6) are connected to the volume expansion part (
The distribution pipes (35_1-3
A pipe length switching valve (38l, 38r) is provided in the middle part of the distribution pipe (35_1 to 35_6), and by controlling the opening of the pipe length switching valve (38l, 38r), the middle part of the distribution pipe (35_1 to 35_6) is connected to the volume expansion part ( An intake system for a multi-cylinder internal combustion engine, characterized in that it is short-circuited to Bg).