JP2583527B2 - 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 system in which intake air supercharging is performed by causing a resonance phenomenon of intake air in an intake system.

(Prior Art) Conventionally, there have been known various ones in which the filling efficiency is increased by a dynamic effect of intake air taken into a combustion chamber in a cylinder of an engine to increase the output torque of the engine. As one example, in Japanese Patent Publication No. Sho 60-14169, for example, an intake passage in a multi-cylinder engine is connected to cylinder groups in which cylinders in which the intake order (ignition order) is not continuous are the same. Divided into two intake passages, each of which is constituted by an enlarged chamber to which a branch section upstream end of the intake manifold is connected, and a resonance intake passage connected to the enlarged chamber,
The upstream end of the resonance intake passage is communicated with the upstream collecting chamber,
A switching device for switching the two intake passages to a communication state or a communication cutoff state is provided in the enlarged chamber, and when the communication between the intake passages is cut off by the switching device, a negative pressure wave generated in the intake stroke of each cylinder is provided. Is reflected in the upstream collecting chamber and inverted to a positive pressure wave, and the inverted positive pressure wave exerts an inertial supercharging effect of intake air in a relatively low rotation range, while allowing each intake passage to communicate with each other. In such a case, the reverse reflection position of the intake pressure wave is brought closer to the intake port, the natural frequency of the intake pressure vibration is increased, and an inertia supercharging effect is obtained in a high-speed rotation range.

Japanese Patent Application Laid-Open No. 59-565 discloses that when the intake air of a V-type engine is supercharged due to its resonance phenomenon, as a specific structure, an outer wall having a space inside is provided between left and right banks of the engine. A plenum-type intake manifold comprising a plurality of ram pipe-type intake pipes arranged to extend annularly along the outer wall in the space of the outer wall in a substantially vertical plane and having a downstream end communicating with each intake port. By placing
It is disclosed that the intake air is supercharged by a compact intake manifold.

In addition, for example, an intake port of each cylinder in a cylinder group in which the intake sequence is not continuous is connected to a resonance intake passage (intake passage) having no volume expansion chamber such as a surge tank, and the resonance frequency of intake air in the resonance intake passage is connected. By setting the length of the intake passage for resonance so that the intake air reaches a specific rotation range of the engine, the intake air can be supercharged by its resonance effect.

(Problems to be Solved by the Invention) By the way, for example, a resonance intake passage is connected to a plurality of cylinders of an engine, and an upstream end of the resonance intake passage is connected to a pressure reversing portion, and the resonance intake passage is connected to the cylinder. When the intake air is supercharged using the resonance phenomenon of the intake air, the propagation state of the pressure wave of the intake air in the resonance state is different due to the variation in the distance from each cylinder to the pressure reversing part, and the intake charge amount differs between the cylinders. And the effect of the dynamic pressure of the intake air flowing into the intake passage for resonance, the amount of intake charge in the cylinder on the most upstream side near the pressure reversal part is larger than that on the downstream side far from the intake supply passage. Become. Therefore, the air-fuel ratio in the upstream cylinder may be too lean toward the lean side, and knocking may occur.

The present invention has been made in view of such a point, and an object of the present invention is to improve the structure of the above-mentioned resonance intake passage itself to suppress the inflow of intake air into the most upstream cylinder in the intake air flow direction, and to improve the resonance region. It is an object of the present invention to reduce the variation in the intake charge amount between cylinders and to suppress the occurrence of knocking due to an uneven air-fuel ratio.

(Means for Solving the Problems) In order to achieve this object, a solution taken in the present invention is to provide a resonance intake passage in a communication portion with the most upstream side cylinder in the resonance intake passage by connecting the resonance intake passage to the cylinder side and the opposite cylinder. A partition wall is provided on each side of the cylinder to provide resistance to the intake air flowing into the most upstream cylinder.

That is, as described above, the configuration of the present invention includes the resonance intake passage communicated with the plurality of cylinders and supercharges the intake by resonance tuning of the intake air in the resonance intake passage. In contrast, at least a portion of the resonance intake passage that communicates with the cylinder on the most upstream side in the intake air flow direction is provided with a partition wall that extends downstream and partitions into a cylinder-side passage and a non-cylinder-side passage. A pressure reversing section for reversing the pressure wave of the intake air is provided in the intake passage upstream of the cylinder at the most upstream side in the flow direction.

(Operation) With the above configuration, according to the present invention, during operation of the engine,
In the resonance intake passage, the positive pressure wave of the intake air which is reversed at the pressure reversing unit and returned to the downstream side is resonantly tuned with the intake air acting on the cylinder, and the intake air is supercharged by the resonance tuned, and the output torque of the engine is increased. Increase.

At this time, a partition wall that partitions the resonance intake passage at that portion into a cylinder-side passage and an anti-cylinder-side passage is provided at least in a portion of the resonance intake passage that communicates with the most upstream cylinder closest to the pressure reversal portion. Therefore, the partition wall receives the resistance of the propagation of the positive pressure wave of the intake air which is reversed at the pressure reversing section and returns to the downstream side, so that the action on the most upstream cylinder is suppressed, and The intake air flow that has flowed into the intake passage is guided downstream by the guide action of the partition wall that extends downstream, and is less likely to flow into the most upstream cylinder. For these reasons, the filling amount of the intake air into the most upstream cylinder is suppressed to be substantially equal to that of the other cylinders, so that the occurrence of knocking due to the variation in the air-fuel ratio between the cylinders can be reduced.

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

FIG. 1 shows an overall configuration of an intake system for an engine according to a first embodiment of the present invention, wherein 1 is a first to fourth units arranged in series.
A fuel injection type four-cylinder engine having four cylinders 2a to 2d, wherein each of the cylinders 2a to 2d is provided with an intake port 3 and an exhaust port (not shown), and each of the intake ports 3 has a capacity expansion chamber such as a surge tank. Is connected to the intake passage 4. The intake passage 4 has an independent intake passage 5, 5,... Having a downstream end connected to the intake port 3 of each of the cylinders 2a to 2d, and a resonance intake passage having an upstream end connected to each of the independent intake passages 5. 6
It is composed of

The downstream end of the resonance intake passage 6 is closed, while the upstream end is connected to an air cleaner 9. The independent intake passage 5 corresponding to the air cleaner 9 and the fourth upstream cylinder 2 d closest to the air cleaner 9. An air flow meter 10 for measuring the amount of intake air, and a throttle valve for restricting the intake passage 4 to a lower side thereof.
11 and are arranged. In addition, the air flow meter 10
The intake passage 6 between the throttle valve 11 and the
In the vicinity of the intake port 3 of each of the cylinders 2a to 2d, a negative pressure wave of the intake air generated at the beginning of the intake stroke of each of the cylinders 2a to 2d is communicated with the resonance intake passage 6 near the intake port 3 of each of the cylinders 2a to 2d. Inside the resonance tank 12, inverts it to a positive pressure wave, and returns the positive pressure wave to the downstream side at the end of the intake stroke of the same cylinder 2a to 2d. By acting, the intake air is inertia-supercharged.

Further, a partition wall 14 extending along the direction of the passage is disposed in the resonance intake passage 6, and the partition wall 14 partially divides the resonance intake passage 6 into the cylinder side passage 7 and the non-cylinder side passage 8. It is divided into. The partition wall 14 is located at the fourth most upstream side from the position immediately downstream of the throttle valve 11.
It extends through the connection to the independent intake passage 5 corresponding to the cylinder 2d to the vicinity of the connection to the independent intake passage 5 corresponding to the second cylinder 2b on the downstream side.

Therefore, in the above-described embodiment, during the operation of the engine 1, each of the cylinders 2 a to 2 d is located near the intake port 3 of each of the cylinders 2 a to 2 d.
The negative pressure wave of the intake air generated at the beginning of the intake stroke of 2a to 2d propagates upstream through the resonance intake passage 6, is reflected by the pressure inverting unit 13 in the middle thereof, and inverts to a positive pressure wave. The positive pressure wave returns to the downstream side, and an inertial supercharging state of the intake air acting at the end of the intake stroke of the same cylinders 2a to 2d occurs, whereby the intake air is supercharged and the output torque of the engine 1 increases.

In this case, the resonance intake passage 6 extends along the passage direction from the position immediately downstream of the throttle valve 11 to the vicinity of the connection to the downstream second cylinder 2b via the connection to the fourth upstream cylinder 2d. The partition wall 14 extends so that a part of the positive pressure wave of the intake air that is reversed by the pressure reversing unit 13 and returned to the downstream side is defined by the partition wall 14. Propagating through the non-cylinder side passage 8, the second cylinder
The action of the pressure wave on the second cylinder 4d to the fourth cylinder 2d is suppressed. In addition, since the intake air flowing from the air cleaner 10 into the resonance intake passage 6 is directed downstream by the guide action of the partition wall 14, it is difficult to flow into the three upstream cylinders 2b to 2d. As a result, the amount of intake air charged to these three cylinders 2b to 2d is suppressed, and becomes equal to that of the first downstream cylinder 2a which is originally difficult to flow structurally.
It is possible to reduce the occurrence of knocking due to the variation of the air-fuel ratio between 2 and 2d.

Further, since such a knocking suppression effect can be obtained only by providing the partition wall 14 in the resonance intake passage 6,
The layout of the intake system does not need to be changed significantly, and the structure can be simplified.

FIG. 2 shows a second embodiment (note that the same parts as in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted), and a range of a partition wall 14 disposed in the resonance intake passage 6 is shown. To
The range is from the connection to the independent intake passage 5 corresponding to the fourth cylinder 2d on the most upstream side to the position immediately upstream of the connection to the independent intake passage 5 corresponding to the third cylinder 2c.

In the case of this embodiment, it is possible to reduce only the intake charge amount to the fourth cylinder 2d on the most upstream side. Therefore, similarly to the first embodiment, the occurrence of knocking of the engine 1 can be suppressed.

FIG. 3 shows a third embodiment, which is applied to a V-type six-cylinder engine.

That is, in this embodiment, the engine 1 'is a V-type six-cylinder engine having six first to sixth cylinders 2'a to 2'f arranged in a V-type, and these six cylinders 2'a ~
The ignition order of 2'f is the same as that of the first cylinder 2'a ~
The order is set in the order of the sixth cylinder 2'f. The six cylinders 2'a to 2'f are composed of three first, third, and fifth cylinders 2'a, 2'c, 2'e, which are not continuous in ignition order, and second, fourth, and fourth cylinders. It is divided into two cylinder groups each composed of three cylinders of six cylinders 2'b, 2'd, 2'f, and one of the three cylinders 2'a, 2'c, 2'e is an engine. The three cylinders 2'b, 2'd, 2'f of the other cylinder group are sequentially formed in the other bank 1'a. I have.

An intake passage 4 'connected to the intake port 3 of each of the cylinders 2'a to 2'f includes an independent intake passage 5, 5,..., A resonance intake passage 6', and an intake supply passage 15. The resonance intake passage 6 'connects a pair of communication passages 6'a, 6'a which are closed at the downstream end and extends linearly, and respective upstream ends of the communication passages 6'a, 6'a. Upstream communication passages 6'b which communicate with the cylinders 2'a, 2'c, 2'e (or 2'b, 2'd of each cylinder group). , 2'f), the upstream ends of three independent intake passages 5, 5, ... are connected.

Further, the intake supply passage 15 has a downstream end connected to a central portion, that is, an upstream end of an upstream communication passage 6'b of the resonance intake passage 6 '. The junction with the supply passage 15 is a pressure reversal section. An upstream end of the intake supply passage 15 is connected to an air cleaner 9, and an air flow meter 10 and a throttle valve 11 are provided in the middle thereof.

The first and second partition walls 14'a and 14'b are disposed in the resonance intake passage 6 '. The first
The partition wall 14'a is located at the most upstream side of one of the cylinder groups in one of the communication passages 6'a from the vicinity of the junction with the intake supply passage 15 in the upstream communication passage 6'b of the resonance intake passage 6 '. It extends to the vicinity of the connection to the third cylinder 2'c downstream from the connection to the fifth cylinder 2'e. On the other hand, similarly, the second partition wall 14'b is connected to the upstream communication path 6'b from the vicinity of the junction with the intake supply path 15 from the other communication path 6'a.
At the most upstream side of the other cylinder group.
It extends to the vicinity of the connection to the fourth cylinder 2'd on the downstream side via the connection to f.

Therefore, in this embodiment, during the operation of the engine 1 ', the inertial supercharging of the intake air is performed for each of the cylinders 2'a to 2'f of each cylinder group. That is, each cylinder 2'a,
Each cylinder 2'a, 2'c, 2'e (or 2'b, 2'd) is located near the intake port 3 of 2'c, 2'e (or 2'b, 2'd, 2'f). , 2 ′
The negative pressure wave of the intake air generated in the early stage of the intake stroke of f) propagates to the upstream side through the communication passage 6'a of the resonance intake passage 6 'and the negative pressure wave from the intake passage 15 of the upstream communication passage 6'b. The reflection at the merging section (pressure reversal section) reverses the pressure to a positive pressure wave, and this positive pressure wave propagates downstream to the same cylinder 2′a, 2′c, 2′e (or 2′b, An inertia supercharging state of the intake air occurs at the end of the intake stroke of 2'd, 2'f).

Also in this embodiment, the amount of intake air for the third and fifth cylinders 2'c, 2'e and the fourth and sixth cylinders 2'd, 2'f on the upstream side in each cylinder group is determined by the partition wall 14 respectively. 'A, 14'b, and thus the engine 1'
Knocking can be reduced.

FIGS. 4 and 5 show a fourth and a fifth embodiment of the present invention, respectively.
The cylinder-side passages 7, 7 'defined by 4'a, 14'b are controlled to be opened and closed by on-off valves.

That is, in the fourth embodiment shown in FIG. 4, in the configuration of the first embodiment (see FIG. 1), the resonance intake passage 6
An on-off valve 16 composed of a butterfly valve for opening and closing the passage 7 is disposed in the cylinder-side passage 7. Further, in the fifth embodiment shown in FIG. 5, in the configuration of the third embodiment (see FIG. 3), an on-off valve 1 is provided in each cylinder side passage 7 'of the resonance intake passage 6'.
6 'is provided.

Therefore, in the case of these embodiments, the on-off valves 16, 16 '
Is opened, the same state as in the first and third embodiments is obtained, and the same operation and effect can be obtained.

On the other hand, when the on-off valves 16, 16 'are closed, the cylinder side passages 7, 7' of the resonance intake passages 6, 6 'are closed, so that the positive pressure wave and the intake air flow which are reflected and return to the downstream side are All of them pass through the non-cylinder side passages 8, 8 ', so that the intake charge amount to the most upstream cylinder can be further reduced, and the occurrence of knocking of the engine 1, 1' can be more effectively suppressed.

It is needless to say that the present invention can be applied to engines other than the in-line four-cylinder and V-type six-cylinder as in the above embodiment.

(Effects of the Invention) As described above, according to the present invention, when a resonance intake passage is connected to a cylinder of an engine and air is supercharged by resonance tuning of intake air in the resonance intake passage,
A partition wall is provided between the cylinder-side passage and the counter-cylinder-side passage in a portion of the resonance intake passage that communicates with the most upstream cylinder, and for inversion of the intake pressure wave in the intake passage upstream of the most upstream cylinder. The pressure reversal part of the cylinder allows the amount of intake air to be charged to the cylinder at the most upstream side by the partition wall to be equal to that of other cylinders, thus effectively preventing the occurrence of knocking due to the variation in air-fuel ratio between cylinders. It can be suppressed.

[Brief description of the drawings]

1 to 5 are schematic plan views showing the entire structure of the first to fifth embodiments of the present invention, respectively. 1,1 '... engine, 2a-2d, 2'a-2'f ... cylinder,
6,6 '… Resonance intake passage, 13… Pressure reversal part, 14,14'
a, 14'b: Partition wall.

Claims (1)

(57) [Claims] 1. An intake system for an engine, comprising: a resonance intake passage communicated with a plurality of cylinders, wherein the intake air is supercharged by resonance tuning of the intake air in the resonance intake passage. A partition wall extending downstream and dividing the resonance intake passage into a cylinder-side passage and a counter-cylinder-side passage is provided at least in a communication portion of the intake passage with a cylinder on the most upstream side in the intake flow direction. An intake system for an engine, further comprising a pressure reversing unit for reversing a pressure wave of intake air in an intake passage upstream of a cylinder on a side of the engine.