JP2779253B2 - Multi-cylinder engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intake device for a multi-cylinder engine,
The present invention relates to a device in which intake air is supercharged by an inertia effect and a resonance effect.

(Prior art) In recent years, in order to improve the output torque of the engine, the intake air supplied to the cylinder of the engine is supercharged by using a dynamic effect such as an inertia effect or a resonance effect, thereby increasing the charging efficiency of the intake air. It has been made to increase.

In the case where the intake air is supercharged by the inertia effect, when a negative pressure wave of the intake air is generated in the intake port at the beginning of the intake stroke of each cylinder with the opening of the intake valve in a predetermined rotation range of the engine (inertia tuning rotation range). The suction negative pressure wave is propagated at a sonic speed in the independent intake passage connected to the intake port toward the upstream side, and the negative pressure wave is inverted into a positive pressure wave in a predetermined volume (volume chamber). Further, this positive pressure wave is propagated at the sonic speed to the downstream side on the same path to reach the intake port of the same cylinder at the end of the intake stroke immediately before the intake valve closes, and the positive pressure wave pushes intake air into the combustion chamber. The filling efficiency is to be improved.

On the other hand, when the intake air is supercharged by the resonance effect, the plurality of cylinders of the engine are divided into cylinders having equal intervals in the intake stroke and grouped into a plurality of cylinder groups, and the independent intake passages of the plurality of cylinders of each cylinder group are formed. At the upstream end, they are gathered in one collective intake passage (resonant intake passage), and a pressure reversing portion composed of a volume portion is provided at a predetermined position in the collective intake passage. Then, the phase of the basic pressure wave of the intake air generated at the intake port of each cylinder of the cylinder group in the resonance tuning rotation range of the engine and the phase of the reflected pressure wave inverted by the pressure inverting unit are made to match, so that the pressure inverting unit and each cylinder The pressure wave of the intake air that reciprocates between and resonates in the collective intake passage. By this resonance, a resonance pressure wave having a large amplitude is generated by the pressure vibration generated individually for each cylinder, and the resonance pressure wave pushes the intake air into the combustion chamber of the cylinder to increase the charging efficiency.

Conventionally, as such an intake device, Japanese Patent Application Laid-Open No. 62-121828
As shown in the publication, independent intake passages connected to each of the plurality of cylinders are respectively connected to two volume chambers defined by partition walls in the surge tank, and the two volume chambers are connected to one end of the surge tank. In addition to providing communication with the main intake passage, providing a communication passage in the partition wall, and arranging an on-off valve in the communication passage, the opening / closing switching of the on-off valve changes the reversal part of the intake pressure wave, thereby widening the rotation of the engine. There is one that can obtain a dynamic effect in a region.

(Problems to be Solved by the Invention) However, in the case of using the surge tank as described above, the length from the upstream passage to the respective independent intake passages in the inside thereof becomes longer as the downstream end cylinder becomes longer. There is a problem that the distribution of intake air and dynamic effects are not uniform.

Therefore, the upstream end of the independent intake passage of each cylinder group is gathered in a collective intake passage extending in the cylinder row direction of each cylinder group, and the combined intake passage is connected to each collective intake passage in such a manner that the downstream ends of the collective intake passages are connected in a ring shape. It is conceivable that a passage is provided to make the distribution of intake air and the dynamic effect uniform for each cylinder, particularly for the cylinder on the downstream side of the collective intake passage. Also according to this one:
The collective intake passage having a narrower cross-sectional area than the surge tank promotes the propagation of the resonance pressure wave, sufficiently eliciting the resonance effect, and the compactness of the intake system can be achieved by eliminating the surge tank.

However, in the above-described configuration, when the engine speed shifts from the resonance tuning speed in the low-speed rotation range to the high-speed rotation range, the charging efficiency of the intake air decreases due to the delay of the resonance pressure wave, and the output torque decreases. Occurs. Therefore, in a fixed intake system in which the inertia effect occurs only if the resonance effect occurs, resonance tuning occurs in a low speed rotation range of the engine, and when inertia tuning occurs in a higher rotation speed range, the resonance tuning occurs in the above inertia tuning rotation speed range. There is a problem that the inertia effect cannot be expected due to the effect of the effect, and a decrease in torque cannot be avoided.

The present invention has been made in view of such a point, and an object of the present invention is to utilize the above-described annularly connected collective intake passages, while sufficiently exhibiting a resonance effect in a low-speed rotation range, and using each collective intake passage. In between, a means is provided to reliably eliminate the resonance pressure wave (resonance effect) that can be sent in the inertial tuning rotation range, suppress the torque reduction due to the resonance effect, and exert the inertia effect at high speed rotation well, and the engine output The purpose is to increase the torque.

(Means for Solving the Problems) In order to achieve the above object, a solution of the present invention according to claim 1 is, as an intake device for a multi-cylinder engine, constituted by a plurality of cylinders in which intake steps are equidistant from each other. It is assumed that a multi-cylinder engine including a plurality of cylinder groups is used. Then, the upstream ends of the independent intake passages respectively communicating with the cylinders of the respective cylinder groups are gathered in a collective intake passage for each cylinder group extending in the cylinder row direction. A connection intake passage is provided to connect the downstream ends of the two in a ring. Further, each of the plurality of cylinder groups has a larger cross-sectional area than the connection intake passage so as to connect the independent intake passages to each other in at least one pair of cylinders corresponding to each other in the cylinder row direction of each cylinder group. A communication passage for communicating the independent intake passages between the cylinder groups is provided, and an on-off valve for opening and controlling the communication between the independent intake passages between the cylinder groups in the inertia tuning rotation range of the engine is provided in the communication passage. Things.

Here, in the invention of claim 2, it is assumed that the set of cylinders communicated by the communication passage in claim 1 is the center cylinder in the cylinder row direction of each cylinder group. According to a third aspect of the present invention, a plurality of communication passages according to the first or second aspect are provided, and the sum of the cross-sectional areas of the plurality of communication passages is set to be larger than the cross-sectional area of the connection intake passage. . Further, in the invention according to claim 4, the connection intake passage according to any one of claims 1 to 3 is provided with an on-off valve for opening and closing the communication between the downstream sides of each of the collective intake passages in the middle speed region of the engine. Shall be.

(Operation) With the above configuration, according to the first to fourth aspects of the present invention, the upstream ends of the independent intake passages of the respective cylinder groups are gathered in the collective intake passages of the cylinder groups extending in the cylinder row direction. A connecting intake passage connecting the downstream ends of the collective intake passages in an annular manner to achieve uniform distribution of intake air to each cylinder and downsizing of the intake system, and a narrow cross-sectional area of the collective intake passage. Promotes the propagation of resonant pressure waves,
The resonance effect is sufficiently exerted in the low speed range of the engine.

In this case, the independent intake passages between the cylinder groups connect the independent intake passages between at least one pair of cylinders corresponding to each other in the cylinder row direction by an on-off valve that is controlled to be opened in the inertia tuning rotation range of the engine. As described above, the communication is performed by the communication passage having a larger cross-sectional area than that of the connection intake passage. Therefore, at the time of high-speed rotation of the engine, inertia tuning occurs in which the communication passage is a reverse portion of the intake pressure wave. The filling efficiency can be increased. In this high-speed rotation range, even if a torque reduction effect is to occur due to a resonance effect generated by a communication path connecting the collective intake passages between the cylinder groups, the communication path is communicated by opening the on-off valve, and the Are connected to each other, the resonance effect is suppressed by the communication, the influence can be eliminated, and the inertia effect can be increased. Furthermore,
According to the fourth aspect of the present invention, the connection intake passage is used as the volume in the middle speed region of the engine, and a good resonance effect can be obtained.

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

FIGS. 1 and 2 show a first embodiment of the present invention.
Is a V-type six-cylinder engine having six first to sixth cylinders 2a to 2f. This engine 1 has a first and a second pair of banks 1a and 1b opposed to each other, and a first bank The first bank 1a has three cylinders of a first cylinder 2a, a third cylinder 2c, and a fifth cylinder 2e, and the second bank 1b has three cylinders of a second cylinder 2b, a fourth cylinder 2d, and a sixth cylinder 2f. Have been. The intake stroke of the cylinders 2a to 2f is, for example, such that the intake stroke proceeds in the order of the first cylinder 2a → the sixth cylinder 2f → the third cylinder 2c → the second cylinder 2b → the fifth cylinder 2e → the fourth cylinder d. It has become. In this embodiment, the six cylinders 2a to 2f are divided into two cylinder groups 3 for every three cylinders so that the intake strokes are equally spaced from each other.
a and 3b.

Reference numeral 4 denotes an intake passage that supplies intake air to each of the cylinders 2a to 2f. The intake passage 4 has three downstream ends connected to three first cylinders 2a, 2c, and 2e of the first cylinder group 3a. Independent intake passages 5a, 5c, 5e and three cylinders 2 of which the downstream end is the second cylinder group 3b
three second independent intake passages 5 respectively connected to b, 2d, 2f
, 5d, 5f, a first collective intake passage 7a connected at an upstream end having the same length from the intake ports 6,... of the first independent intake passages 5a, 5c, 5e, and a second independent intake passage 5b. , 5d, 5f intake port
And a second collective intake passage 7b connected at the upstream end having an equal length from 6,. These are the first bank of Engine 1.
1a, the upstream ends of which are connected to the main intake passage 8, respectively. An upstream end of the main intake passage 8 is connected to an air cleaner 9, and an air flow meter 10 for detecting an intake air amount is provided in the middle of the main intake passage 8.

Independent intake passages 5a of the first and second cylinder groups 3a, 3b
5 to 5f are first to sixth upstream-side independent intake passage portions 11a to 11f formed in the engine 1 and each having an upstream end opening through an intake valve (not shown) to each of the cylinders 2a to 2f. It comprises first to sixth downstream independent intake passage portions 12a to 12f connected to the downstream side of the first to sixth upstream independent intake passage portions 11a to 11f and extending outward of the engine 1. In this case, each of the independent intake passages 5a to 5f of the first and second cylinder groups 3a and 3b is divided into three independent intake passages 5 of each of the cylinder groups 3a and 3b by the above-described arrangement structure.
The lengths of a, 5c, 5e (5b, 5d, 5f) are made equal, and the intake air flow resistance is made uniform.

Further, the first and second collective intake passages 7a, 7a,
A communication path 7b connects the third and fourth independent intake passages 5c and 5d of the third and fourth cylinders 2c and 2d corresponding to each other at the center of the first and second cylinder groups 3a and 3b in the cylinder row direction. the by L ₂ substantially matches the path length 1, a second set intake passage 7a, and connecting the intake passage 13 is provided to connect the downstream end each other 7b, the connection intake passage
At one end of 13, a normally closed first butterfly valve 14 is provided as an on-off valve for controlling the communication at the downstream ends of the two combined intake passages 7a and 7b to be open in the middle speed region of the engine 1. In this case, by opening the first butterfly valve 14, the connection intake passage 13 is used as a volume in the middle speed region of the engine 1, and a good resonance effect is obtained.

Then, the first and second independent intake passages 5c and 5d of the third and fourth cylinders 2c and 2d corresponding to each other are located at the center of the first and second cylinder groups 3a and 3b in the cylinder row direction, respectively. A communication path L shorter than a communication path L ₁ (a communication path on the side of the connection intake path 13) connecting the third and fourth independent intake paths 5 c and 5 d to each other at a short distance in the second collective intake paths 7 a and 7 b. ₂ , the third and fourth independent intake passages 5c and 5d are connected to each other, and the communication path L ₁
Third and fourth independent intake passage 5c has a larger cross-sectional area with a large pipe diameter X ₂ than the pipe diameter X _1, it is communicating passage 15 connecting 5d each other are connected to. The first and second communication paths 15
A normally-closed second butterfly valve 16 as an on-off valve for opening and closing the communication between the first and second collective intake passages 6 and 7 between the cylinder groups 3a and 3b in the inertia tuning rotation range (high speed rotation range) of the engine is provided. Is provided.

Therefore, in this embodiment, the upstream ends of the independent intake passages 5a to 5f for each of the cylinder groups 3a and 3b are gathered in the first and second aggregate intake passages 7a and 7b extending in the cylinder row direction for each of the cylinder groups 3a and 3b. In each of the collective intake passages 7a and 7b, a connection intake passage 13 that connects the downstream ends of the collective intake passages 7a and 7b in an annular manner is provided, so that the distribution of intake air to the cylinders 2a to 2f is uniform and the intake air is uniform. In addition to reducing the size of the system, the propagation of resonance pressure waves is promoted by the collective intake passages 7a and 7b whose cross-sectional area is narrower than that of a surge tank, etc., and resonance occurs in the low and medium speed rotation range of the engine 1. The effect is fully demonstrated.

In this case, the second butterfly valve 16 that is opened in the inertia tuning rotation range (high-speed rotation range) of the engine 1 connects the first and second collective intake passages 7a and 7b of each cylinder group 3a and 3b with each cylinder. Third and fourth cylinders 2c, 2 corresponding to each other at the center of the groups 3a, 3b in the cylinder row direction.
third and fourth independent intake passage 5c of d, connected by a short communication paths L ₂ than the communicating path L ₁ connecting the 5d each other over a short distance, and communication path L ₁ of the larger pipe diameter X ₂ than the tube diameter X ₁ Therefore, when the engine 1 rotates at a high speed, inertia tuning occurs in which the communication path 15 is a reverse portion of the intake pressure wave, and the inertia effect enhances the charging efficiency of the intake air. be able to. In this high speed range, the first and second cylinder groups
Communication path L ₁ connecting first and second collective intake passages 7a and 7b between 3a and 3b
When the second butterfly valve 16 is opened, the communication path 15 is communicated, and the independent intake passage 5a between the first and second cylinder groups 3a, 3b is caused. 5f are communicated with each other, the resonance effect is suppressed by this communication, the influence can be eliminated, and the inertia effect can be increased.

With this effect, a high resonance effect can be obtained in the low / medium speed rotation range of the engine 1, while a high inertia effect can be obtained in the high speed rotation range without the influence of the resonance effect.

(Other Embodiments) FIG. 3 shows a second embodiment (in the following embodiments, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. ), The communication path is changed.

In this embodiment, the upstream ends of the third and fourth independent intake passages 5c, 5d of the third and fourth cylinders 2c, 2d corresponding to each other at the center of the first and second cylinder groups 3a, 3b in the cylinder row direction are arranged. the first and second set intake passage 7a but correspond respectively to 7b, the third and fourth independent intake passage 5c, third and a short communication paths L ₂ than the communicating path L ₁ connecting the 5d each other at a short distance Two communication passages 21, 21 connecting the fourth independent intake passages 5c, 5b are connected. The sum of the cross-sectional areas of both the communication passage 21, tube diameter X ₁ of the communication path L ₁
Is set larger than the cross-sectional area of. In addition, the communication passage 21 has a normally closed state in which the communication between the first and second collective intake passages 6 and 7 between the first and second cylinder groups 3a and 3b is controlled to be open in the inertia tuning rotation range of the engine. The second butterfly valves 22 and 22 (open / close valves) are provided.

Therefore, in this embodiment, the communication paths 21 and 21 are communicated by opening the second butterfly valves 22 in the high-speed rotation range, and the first and second butterfly valves 22 are opened.
Since the cylinder groups 3a, each independent intake passage 5a~5f each other between 3b communicated, first, second cylinder group 3a, a first inter-3b, the second set intake passage 7a, the communicating path L ₁ connecting 7b Thus, the effect of reducing the torque due to the resonance effect caused by the above can be suppressed to eliminate the effect, and the inertia effect can be increased. In this embodiment, effects similar to those of the above embodiment can be obtained.

FIG. 4 shows a third embodiment. In this embodiment, the first and second cylinders 2a, 2a at the both ends in the cylinder row direction of the first and second cylinder groups 3a, 3b are shown.
The upstream ends of the first and second independent intake passages 5a and 5b of the second cylinder 2b, and the fifth and sixth independent intake passages 5e and 5e of the fifth and sixth cylinders 2e and 2f.
The upstream ends of 5f correspond to the first and second collective intake passages 7a, 7b respectively corresponding to the fifth and sixth independent intake passages 5e, 5e.
Connecting the intake passage 13 side connecting 5f together over a short distance (both collectively intake passage 7a, 7b downstream) the first communication path L ₁ and both the set intake passage 7a in shorter than the second communication path L ₃ in 7b upstream _Two communication paths 31, 31 connecting the fifth and sixth independent intake paths 5e, 5f are connected to each other through a communication path L2. The sum of the cross-sectional areas of both the communication passage 31 is set to be larger than the cross-sectional area of the pipe diameter X ₁ of the first communication path L _1. The two-way passage 31 is normally closed so that the communication between the first and second collective intake passages 6 and 7 between the first and second cylinder groups 3a and 3b is controlled to be open in an engine inertia tuning rotation range. Are provided.

Accordingly, in this embodiment, the communication paths 31, 31 are communicated by opening the second butterfly valves 32 in the high-speed rotation range, and the first and second butterfly valves 32 are opened.
Since the cylinder groups 3a, each independent intake passage 5a~5f each other between 3b communicated, first, second cylinder group 3a, a first inter-3b, the second set intake passage 7a, the communicating path L ₁ connecting 7b Thus, the effect of reducing the torque due to the resonance effect caused by the above can be suppressed to eliminate the effect, and the inertia effect can be increased. In this embodiment, effects similar to those of the above embodiment can be obtained.

FIG. 5 shows a fourth embodiment in which the connection of the main intake passage 8 to both the combined intake passages 7a and 7b is changed. That is, in this embodiment, in addition to the configuration of the third embodiment, first and second end portions of the first and second collective intake passages 7a and 7b are provided.
Third and third cylinder groups 3a and 3b corresponding to each other at the center in the cylinder row direction.
The third and fourth independent intake passages 5c and 5d of the fourth cylinders 2c and 2d have a path length substantially matching each other, and the first and second collective intake passages 7 have the same length.
Connection intake passages 41, 41 are provided to connect a and 7b in a ring shape. Also,
One end of one of the connection intake passages 41 (the right side in the figure) is connected to one end of the connection intake passage 41 so as to open and close the communication between the two combined intake passages 7a and 7b in the middle speed region of the engine. One butterfly valve 42 is provided. Then, the first and second cylinder groups 3a, 3b
Third and fourth cylinders 2c, 2 located at the center of each other in the cylinder row direction
In the first and second collective intake passages 7a and 7b where the upstream ends of the third and fourth independent intake passages 5c and 5d are located,
The two downstream ends of the main intake passage 8 are connected to each other.

Accordingly, in this embodiment, the communication paths 31, 31 are communicated by opening the second butterfly valves 32 in the high-speed rotation range, and the first and second butterfly valves 32 are opened.
Since the respective independent intake passages 5a to 5f between the cylinder groups 3a and 3b are communicated with each other, connection intake that connects the first and second collective intake passages 7a and 7b between the first and second cylinder groups 3a and 3b in a ring shape. The torque reduction effect due to the resonance effect generated by the communication path via the passage 41 is suppressed to eliminate the effect, and the inertia effect can be increased. In this embodiment, effects similar to those of the above embodiment can be obtained.

In each of the above embodiments, the first and second cylinder groups 3a and 3b
1, the second set intake passage 7a, in 7b, the third and fourth independent intake passages 5c, and 5d together with short communication paths L ₂ than the communicating path L ₁ connecting a short distance, and tubing communicating path L ₁ first with larger cross-sectional area than the cross-sectional area of the diameter X _1, second set intake passage 7a, but the communication path 15,21,31 connecting 7b together respectively connected, first, the first every second cylinder group A communication path connecting the first and second collection intake paths to the second collection intake path with a communication path shorter than a communication path connecting the third and fourth independent intake paths with each other at a short distance; The communication path connecting the first and second collective intake paths may be connected with a cross-sectional area larger than the cross-sectional area of the pipe diameter of the communication path connecting the four independent intake paths at a short distance.

The above-described embodiment is an example in which the present invention is applied to a V-type six-cylinder engine 1. However, the present invention also includes an in-line four-cylinder, six-cylinder and eight-cylinder engine, a V-type eight-cylinder and a twelve-cylinder. It can also be applied to engines such as engines. For example,
In the case of a V-type 12-cylinder engine, the intake strokes are equally spaced 6
In addition to grouping two cylinder groups for each cylinder, three cylinders can be grouped and divided into four cylinder groups.

(Effects of the Invention) As described above, according to the intake device for a multi-cylinder engine according to the first to fourth aspects of the present invention, the collective intake passage for each cylinder group extends in the cylinder row direction at the upstream end of the independent intake passage for each cylinder group. And the connecting intake passages connecting the downstream ends of each of the collective intake passages in a ring shape to reduce the size of the intake system. The propagation of the resonance pressure wave is promoted by the collective intake passage with a narrow cross-sectional area. Thus, a high resonance effect can be obtained in the low-speed rotation range of the engine, while the on-off valve connects the independent intake passages between at least one pair of corresponding cylinders in the cylinder row direction of each cylinder group. A communication passage having a larger cross-sectional area than the intake passage allows communication between the collective intake passages of each cylinder group in the inertial tuning rotation range of the engine, thereby producing inertial tuning in which the communication passage is a reverse portion of the intake pressure wave. In the event of kinking, the effect of the resonance effect is eliminated, and a high inertia effect can be obtained in the high-speed rotation range of the engine.

[Brief description of the drawings]

1 and 2 show a first embodiment of the present invention.
FIG. 2 is a plan view of the engine and the intake system, and FIG. 2 is a schematic plan view of the same. 3 to 5 are views corresponding to FIG. 1 showing other embodiments. 1 ... Engines 2a-2f ... Cylinders 3a, 3b ... Cylinder group 4 ... Intake passages 5a-5f ... Independent intake passages 7a, 7b ... Collective intake passages 13,41 ... Connection intake passages 15,21, 31 ...... communication passage 16,22,32 ...... second butterfly valve (on-off valve) L _1, L ₃ communicating path ...... connecting the intake passage side communicating path L ₂ ...... communicating passage side

Claims (4)

(57) [Claims] 1. A multi-cylinder engine including a plurality of cylinder groups each of which has a plurality of cylinders whose intake strokes are equally spaced from each other, wherein an upstream end of an independent intake passage communicating with the cylinders of each of the cylinder groups. Are gathered in a collective intake passage for each cylinder group extending in the cylinder row direction, and the collective intake passage for each cylinder group is provided with a connection intake passage that connects the downstream ends of the collective intake passages in a ring shape, Between the collective intake passages of the cylinder groups, at least one of the cylinder groups corresponding to each other in the cylinder row direction of the cylinder groups.
A communication passage is provided for connecting the independent intake passages between the cylinder groups with a larger sectional area than the connection intake passage so as to connect the independent intake passages between the pairs of cylinders, and the communication passage includes: An intake device for a multi-cylinder engine, comprising: an on-off valve for opening and closing communication between independent intake passages between respective cylinder groups in an inertia tuning rotation range of the engine. 2. A set of cylinders communicated by a communication passage,
2. The intake device for a multi-cylinder engine according to claim 1, wherein each of the cylinder groups is a center cylinder in a cylinder row direction. 3. The intake device for a multi-cylinder engine according to claim 1, wherein a plurality of communication passages are provided, and a total of the cross-sectional areas of the plurality of communication passages is set to be larger than a cross-sectional area of the connection intake passage. 4. The multi-cylinder according to claim 1, wherein the connecting intake passage is provided with an on-off valve for opening and closing the communication between the downstream ends of each of the collective intake passages in a middle speed region of the engine. Engine intake device.