JPH071006B2 - Internal combustion engine intake system - Google Patents

Description

The present invention relates to an intake system for an internal combustion engine, and more particularly to an intake system for performing resonance supercharging to improve output torque of the internal combustion engine.

<Prior Art> Conventionally, various techniques have been known for increasing the charging efficiency and increasing the output torque of an internal combustion engine by utilizing the intake resonance in the intake passage. However, in such an intake system, effective resonance supercharging is performed only in a specific rotation speed range, and in other speed ranges, the resonance structure of the intake system causes the output torque of the internal combustion engine to change. There was a problem of rather lowering.

Japanese Unexamined Patent Publication (Kokai) No. 62-101820 by the same applicant proposes an intake device which is a combination of resonance supercharging and inertia supercharging. According to this prior art, a high output torque can be generated over a wide range of the engine rotation speed by appropriately combining the torque peaks due to the resonance supercharging and the inertia supercharging. However, the structure of the intake passage becomes relatively complicated, and it may be difficult to apply the structure in some cases, and in reality, it is not always possible to eliminate the variation in the output torque at each rotation speed.

<Problems to be Solved by the Invention> In view of such conventional problems, the main object of the present invention is to
It is an object of the present invention to provide an economical and effective intake device capable of improving output torque by resonance supercharging over a wide range of rotation speed of an internal combustion engine.

[Configuration of the Invention] <Means for Solving the Problems> According to the present invention, a pair of cylinder groups each including a plurality of cylinders and a pair of intake passages leading to the cylinder groups are provided. And a pair of resonance chambers that communicate with each other through a pair of branch passages that branch from each of the intake passages, and a communication passage that communicates the resonance chambers with each other. Opening / closing control of a first opening / closing control valve provided in each of the branch passages, a second opening / closing control valve provided in the communication passage, and the first and second opening / closing control valves according to the rotation speed of the internal combustion engine It is achieved by providing an intake system for an internal combustion engine, characterized in that it comprises a control unit that valves.

<Operation> In this way, the resonance characteristics of the intake device can be selectively set to three different states by appropriately opening / closing the first and second opening / closing control valves.
By setting the most appropriate state of the on-off control valve in each rotation speed range of the internal combustion engine, high output torque can be obtained over a wide speed range of the internal combustion engine.

<Embodiment> Hereinafter, the present invention will be described in detail with reference to a specific embodiment with reference to the accompanying drawings.

1 and 2 show an embodiment in which the intake system according to the present invention is applied to a V-type 6-cylinder engine.

This engine has one cylinder group 1 consisting of the three cylinders on the upper right in FIG. 1 and the other cylinder group 2 consisting of the three cylinders on the lower left. Further, in the intake device of this engine, the intake pipe 3, the air cleaner 4, the intake pipe 5, the surge tank 6, the pair of branched intake pipes 7 and 8 and the intake manifold bodies 9 and 10 are arranged in this order from the upstream side. It is provided and connected to the cylinder head of the engine body 15. In addition, in the lower portions of the intake manifold bodies 9 and 10, the resonance container 11 and
12 are fixed integrally. The resonance vessels 11 and 12 are respectively connected to the downstream ends of the intake pipes 7 and 8 through branch pipes 13 and 14. By holding the resonance vessels 11 and 12 in the V-shaped valley portion of the engine body 15 with a stay (not shown), the intake manifold bodies 9 and 10 are also held at the same time. Therefore, the number of parts is reduced as compared with the case where they are separately fixed.

On the other hand, inside the intake device, as shown in FIG. 2, the intake pipe 3, the air cleaner 4, the intake passage 5a defined by the inside of the intake pipe 5, the inside of the surge tank 6 and the two intake pipes 7 are shown in FIG. , 8 inside the intake passages 7a, 8a, throttle valves 16 and 17 composed of butterfly valves provided at the downstream ends of the intake passages 7a and 8a, which are interlocked with each other, and the intake manifold bodies 9 and 10, respectively. The combustion chambers are communicated with each other through the defined intake chambers 9a, 10a, the intake ports 9b, 10b, and the intake valves 18 provided in each cylinder of the cylinder groups 1 and 2. Also,
Each combustion chamber communicates with exhaust pipes 23, 24 via an exhaust valve 19 and exhaust ports 21, 22, the exhaust pipes are gathered together outside the drawing, and communicate with the atmosphere via a muffler.

In the vicinity of the downstream side intake chambers 9a, 10a in each intake passage 7a, 8a, the branch passages 13a, 1 formed inside the branch pipes 13, 14 are provided.
One end of 4a is connected to each. These branch passages 13a, 1
The other end of 4a is connected to the internal resonance chambers 11a and 12a of the resonance vessels 11 and 12, respectively. Intake passages 7a, 8a of the branch passages 13a, 14a
First opening / closing control valves 25 and 26 are respectively provided at the openings facing. Further, the resonance chambers 11a and 12a can be selectively communicated with each other by a communication passage 28a of a communication pipe 28 provided with a second opening / closing control valve 27. These first open / close control valves 2
5, 26 and the second opening / closing control valve 27 are respectively connected to the actuator 2
Opening / closing control is performed by the control unit 31 via 9 and 30.

As shown in FIG. 2, the end portions of the intake chambers 9a and 10a and the openings of the branch passages 13a and 14a are arranged close to each other. 9a, 10
This is because the position where the resonance effect is highest with the a end is the position as close as possible to the air cleaner 4 or the ends of the intake chambers 9a and 10a. Actually, with the passage length L1,
The relationship with the distance L2 from each intake chamber 9a, 10a end to each branch passage 13a, 14a opening is L2 <L1 / 4, preferably for each intake chamber 9a, 10a end It is advisable to bring the openings of the branch passages 13a and 14a as close as possible.

Next, the operation procedure of the present invention will be described with reference to FIGS.

In the low speed range of the internal combustion engine, the first opening / closing control valves 25, 26
And the second opening / closing control valve 27 is in a closed state. Therefore, the intake air is exclusively supplied to the cylinder groups 1 and 2 through the intake passages 7a and 8a, and the resonance effect thereof produces a torque curve as shown by a curve I in FIG. 3, which is the lowest. The torque peak in the speed range (first order resonance) is utilized.

Next, when the rotation speed has increased to N1, the second opening / closing control valve 27 is kept closed and the first opening / closing control valves 25 and 26 are simultaneously opened. As a result, the resonance characteristics of the intake passage 7a and the resonance chamber 11a are coupled, the resonance characteristics of the intake passage 8a and the resonance chamber 12a are coupled, and a resonance effect is produced before and after the rotational speed at which vibrations resonate with each other. A torque curve as shown by the increasing curve II is obtained and when the rotation speed is between N1 and N2 (N1 <
N2), torque peak in the lower speed range (first resonance)
Is utilized.

When the rotation speed is between N2 and N3 (N2 <N3), the above-mentioned state is taken again, that is, each open / close control valve 25-
By closing all 27, the intermediate torque peak (secondary resonance) of the torque curve represented by curve I is exploited.

When the rotation speed is between N3 and N4 (N3 <N4), all the open / close control valves 25 to 27 are opened. As a result, a torque curve having an intermediate tendency between the curve I and the curve II as shown by the curve III is obtained, and the torque peak (secondary resonance) in the higher speed range is utilized.

When the rotation speed exceeds N4, all the on-off control valves 25 to 27 are closed again, and the torque peak in the highest speed range of the torque curve represented by the curve I is utilized, resulting in a large output torque even in the high speed rotation range. Obtainable.

In the present embodiment, the valves 25 to 27 are controlled to open and close at four predetermined engine speeds (N1 to N4) to change the resonance characteristics, but the opening and closing control valves do not flutter. In addition, the valves 25 to 27 may be controlled to open and close in order to efficiently utilize the torque curves of the curves (I to III) shown in FIG.

Further, it is desirable that the on-off control valve is opened and closed gradually to reduce shock, and if desired, when the internal combustion engine is idle, when the rotation speed changes abruptly, or when the load is increased. When it is small, the opening / closing of the opening / closing control valve may be prohibited in order to improve the durability of the mechanical movable portion.

Further, as shown in FIG. 4 in which only the intake passage 7a side is enlarged, in this embodiment, the branch passage 13a has a circular cross section and a substantially circular butterfly valve is rotated to rotate the resonance chamber 11a.
Is connected to each intake passage 7a, but in order to prevent the air flow from being disturbed at the opening edge of the branch passage 13a, the throttle valve
It is advisable to rotate 16 in a direction in which the edge portion on the opening side moves away from the opening, as indicated by the imaginary line. For the same reason, the opening / closing control valve 25 is changed by the throttle valve as indicated by the imaginary line. It is advisable to rotate the side edge in a direction away from the opening. This means that the branch passage 14 on the intake passage 8a side
It goes without saying that the same applies to a, the throttle valve 17, and the opening / closing control valve 25.

5 to 8 show a modified embodiment of the above embodiment. When butterfly valves are used for the first opening / closing control valves 25 and 26 as in the above embodiment, the valve body and the imaginary line A are formed in the portion of the branch passage 13a that opens to the intake passage 7a when the valves are closed. It is conceivable that the airflow will be disturbed due to the formation of voids between the and (Fig. 4). Therefore, as shown in FIG.
The branch passage 33a communicating with 11a has a semicircular cross section, and the first opening / closing control valve 35 cantilevered by providing a rotating shaft 35a in a straight portion of a valve body along the passage so that the passage is opened and closed. By doing so, as well shown in FIG. 6, no air gap is unnecessarily generated in the valve closed state, and there is no fear of disturbing the air flow in the intake passage 7a. At this time, the branch passage 33a may be formed so that the rotating shaft 35a is located on the upstream side of the intake passage 7a.

Further, as shown in FIG. 7, the branch passage 43a has a substantially elliptical cross-sectional shape, and a rotary shaft 45a is provided at a position where a curved portion and a straight portion of the valve body along the passage intersect. If the first opening / closing control valve 45 is used to open and close the passage, as shown in FIG. 8, the unnecessary air gap can be made as small as possible in the closed state, and the intake passage 7a There is no fear of disturbing the air flow. At this time, the rotary shaft 45a is connected to the intake passage 7a.
It is advisable to form the branch passage 43a on the upstream side of the.
Needless to say, the branch passage shape and the structure of the first opening / closing control valve can be similarly applied to the other first passage and the first opening / closing control valve.

The present invention is suitable for an internal combustion engine having one cylinder group and three cylinders or less. However, when it is one cylinder group and three cylinders or less, the intake valve opening timing period between the cylinders in each cylinder group This is because a particularly remarkable effect of resonance supercharging can be obtained due to the absence of the overlap. However, 1
In an internal combustion engine in which the opening timing of the intake valve is variable according to the rotation speed and the like even in the four-cylinder group, there are cases where the opening timing of the intake valve does not overlap between the cylinders during low speed rotation or idle rotation. It is easy to apply the present invention to such an internal combustion engine.

[Effects of the Invention] As described above, according to the present invention, a large output torque can be obtained over a wide range of the rotation speed of the internal combustion engine with a relatively simple structure, so that the effects are extremely large. is there.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing the outline of an intake device according to the present invention. FIG. 2 is a schematic configuration diagram showing an outline of the intake device according to the present invention. FIG. 3 is a graph showing the output torque characteristics obtained by the embodiment shown in FIGS. 1 and 2. FIG. 4 is an enlarged view of a main part of FIG. FIG. 5 to FIG. 8 are schematic diagrams of a pipeline and an opening / closing control valve showing a modified example of the embodiment shown in FIGS. 1 to 4. 1, 2 ... Cylinder group, 3 ... Intake pipe 4 ... Air cleaner, 5 ... Intake pipe 5a ... Intake passage, 6 ... Surge tank 7, 8 ... Intake pipe, 7a, 8a ... Intake passage 9 , 10 ... Intake manifold body 9a, 10a ... Intake chamber, 9b, 10b ... Intake port 11, 12 ... Resonance vessel, 11a, 12a ... Resonance chamber 13, 14 ... Branch pipe 13a, 14a .. Passage 15 …… Engine body, 16, 17 …… Throttle valve 18 …… Intake valve, 19 …… Exhaust valve 21,22 …… Exhaust port 23,24 …… Exhaust pipe 25,26 …… First opening / closing control valve 27 ...... Second open / close control valve, 28 ...... Communication pipe 28a ...... Communication passage 29,30 ...... Actuator 31 ...... Control unit, 33a ...... Branch passage 35 ...... First open / close control valve, 35a ...... Rotating shaft 43a …… Branch passage, 45 …… First opening / closing control valve 45a …… Rotating shaft

Claims (1)

[Claims] 1. A pair of cylinder groups each comprising a plurality of cylinders,
An intake system for an internal combustion engine, comprising: a pair of intake passages reaching each of the cylinder groups; a pair of resonance chambers communicating with each other through a pair of branch passages branching from the intake passages; A communication passage that connects the resonance chambers to each other; a first opening / closing control valve provided in each of the branch passages; a second opening / closing control valve provided in the communication passage; and the first and second opening / closing control valves. An intake system for an internal combustion engine, comprising: a control unit that performs opening / closing control according to a rotation speed of the internal combustion engine.