JPH07139360A - Intake system of v-type engine - Google Patents

Abstract

PURPOSE:To utilize dynamic supercharging to enhance charging efficiency by bending a downstream communicating part against first and second intake gas supply passages, and arranging the downstream communicating part and the first and second intake gas supply passages so as to be piled up and down. CONSTITUTION:First and second intake gas supply passages 6a, 6b of a circular passage 6 are arranged in a space between banks 1, 2 in a way that they extend in parallel in the cylinder arranging direction and are mutually connected on the front and rear sides of an engine main body. The upstream part of the circular passage 6 is bent along the edge of the bank 2 and connected to a common intake passage 7 in the outside part of the bank 2. A downstream communicating part 6c of the circular passage 6 is folded back upward so as to be piled up and down on the first and second intake gas supply passages 6a, 6b. Pressure waves propagating through the circular passage 6 are intensified to exert resonance effect and charging efficiency is enhanced. Since an expansion chamber is eliminated, an intake system is made compact and can be built-in in an engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine, which is designed to enhance intake charging efficiency by a resonance effect.

[0002]

2. Description of the Related Art Conventionally, various engine intake systems have been known which are designed to enhance the charging efficiency by the dynamic effect of intake air. For example, in the device disclosed in Japanese Examined Patent Publication No. 60-14169, in a multi-cylinder engine, two intake passages are respectively connected to a cylinder group of 2 groups in which cylinders whose intake order is not continuous are the same group. And each of the intake passages is configured to include an expansion chamber (a large-volume collecting chamber) to which the upstream end of the intake manifold branch is connected, and a resonance passage extending upstream from the expansion chamber, A switching device capable of interrupting communication between the intake passages is provided in the expansion chamber or the like, and the upstream ends of the intake passages are connected to the upstream collecting chamber. According to this device, when the switching device is in a state of blocking the intake passages from each other,
Due to the intake pressure wave that is inverted and reflected in the upstream side collection chamber,
When the inertial supercharging effect is obtained in the region where the engine speed is relatively low and the switching device is in a state of communicating with the intake passages, the reversal reflection position of the pressure wave should be close to the intake port. As a result, the inertia supercharging effect can be obtained in the region where the engine speed is relatively high.

However, according to this intake device, since the expansion chamber having a large volume is provided in the portion where the intake manifold branch portion is gathered, the intake system becomes large and a large installation space is required when the intake system is installed in an automobile. There is an inconvenience such as the need for space.

Further, in the V-type engine, as shown in, for example, Japanese Patent Laid-Open No. 59-565, in the space between the banks, curved intake passages corresponding to the branch portions and the individual intake passages are provided. There is a structure in which an intake manifold having a space corresponding to an expansion chamber that communicates with a passage is arranged to have an inertia supercharging effect and to be downsized. However, even with this structure, the intake manifold located between both banks is provided with an expansion chamber that communicates with the branch, so it is possible to avoid the intake manifold from protruding a considerable amount above the top of the bank. Therefore, the height of the entire engine becomes large, and it becomes difficult to keep the bonnet height low when the engine is mounted on an automobile.

[0005]

That is, according to the structure in which the intake manifold branch portion is connected to the expansion chamber as in these conventional devices, there is a limit to downsizing (especially height reduction). For this reason, the expansion chamber is abolished and, for example, the cylinders whose intake orders are not consecutive are made the same group 2
Two pipe-shaped intake passages without expansion chambers are connected to each intake port of each cylinder group via short branch pipes, and both intake passages are gathered at appropriate points on the upstream side. It is conceivable to reversely reflect the pressure wave at this portion. However, in this case, there is a difference in the length of the pressure wave propagation path between the intake port and the pressure wave inversion reflection part for each cylinder, and the intake passage is shortened in expectation of the supercharging effect particularly in the high speed range. Then, the difference becomes relatively large, and the action of the pressure wave on each cylinder is unbalanced, so that it becomes difficult to exert a sufficient supercharging effect on each cylinder.

In view of the above circumstances, the present invention provides an engine capable of effectively increasing the charging efficiency while eliminating the need for an expansion chamber, in particular making the intake system sufficiently compact and increasing the dynamic effect. An intake device is provided.

[0007]

The apparatus of the present invention comprises a first intake air supply passage for supplying intake air to the cylinders of one bank and an intake air passage communicating with the intake port of each cylinder of a V-type engine. It is composed of a second intake supply passage for supplying intake air to the cylinders of the bank, and an upstream communication portion and a downstream communication portion that communicate both intake supply passages, and is formed in an annular shape so as to circulate the pressure wave propagating from each intake port. An intake system for a V-type engine having a resonance annular passage, wherein both of the intake supply passages are arranged between the banks so that the passage axial direction is parallel to the cylinder row direction. The downstream side communication portion is bent with respect to the intake air supply passage so that the downstream side communication portion and both intake air supply passages are vertically overlapped.

[0008]

According to this structure, the resonance effect is obtained between the cylinders by the pressure wave propagating through the resonance annular passage. When such an annular passage for resonance is provided, since there is a portion that serves as a propagation path for pressure waves but not as a circulation path for intake air in the annular passage for resonance, the passage area of this portion is set to a relative value. By making the diameter thinner, the resonance annular passage can be made compact and the intake pressure wave can be strengthened without disturbing the flow of intake air.

[0009]

1 and 2 show a device according to the present invention as a V type 6
It shows an example when applied to a cylinder engine,
One bank 1 of the V-type engine is provided with three cylinders 3a, 3b, 3c of No. 1, No. 2, and No. 3, and the other bank 2 is provided with three cylinders No. 4, No. 5, No. Cylinders 3d, 3e,
3f is provided. Ignition order of each cylinder (intake order)
Is, for example, the first cylinder 3a → the fourth cylinder 3d → the second cylinder 3
b → 5th cylinder 3e → 3rd cylinder 3c → 6th cylinder 3f, each cylinder 3a to 3c in one bank 1 constitutes a first cylinder group in which the intake order is not continuous, and the other bank 2 The respective cylinders 3d to 3f in No. 2 constitute a second cylinder group in which the intake order is not continuous. Intake ports 4a to 4f and exhaust port 5a are provided in the cylinders 3a to 3f, respectively.
.. to 5f are provided, and these intake ports 4a to 4f are provided.
The exhaust ports 5a to 5f are opened and closed at predetermined timings by an intake valve and an exhaust valve (not shown).

The intake ports 4a to 4f of the respective cylinders are connected to a resonance annular passage 6 having no expansion chamber, and the resonance annular passage 6 is connected to an air cleaner 8 and a throttle valve 9.
It is connected to a common intake passage 7 for introducing intake air via.

The resonance annular passage 6 is provided in the first cylinder group.
The short branch pipes 10a-10 are attached to the respective intake ports 4a-4c of the pump.
A passage 6a communicating via c and a passage 6b communicating to the intake ports 4d to 4f of the second cylinder group via short branch pipes 10d to 10f extend in two directions, upstream and downstream, respectively. The upstream end and the downstream end connected to the common intake passage 7 are connected to each other to form an annular shape.

The portion of the resonance annular passage 6 other than the intake air flow passage is formed thinner than the portion which becomes the intake air flow passage. That is, in the case of the present embodiment, the resonance annular passage 6
In each of the intake ports 4a-4c of the first cylinder group,
And a portion to which the intake ports 4d to 4f of the second cylinder group are connected, respectively, and a communicating portion between the cylinder groups upstream thereof (a portion where the passages 6a and 6b extend to the upstream side and communicate with each other). Is an intake air flow passage through which the intake air introduced from the common intake air passage 7 into each of the cylinders 3a to 3f passes, but the downstream side communication portion between the cylinder groups (the passages 6a and 6b extend to the downstream side and are connected to each other). The portion 6c is out of the intake air circulation path, and almost no intake air flows. Therefore, the portion serving as the intake air flow passage is formed so as to have the passage area S ₁ required to reduce the intake resistance and secure the intake air flow rate, while the downstream side communication portion 6c is formed in the intake air flow passage. It is formed in the passage area S ₂ smaller than the portion to be.

As shown in FIG. 2, a specific structure for incorporating such an intake system into a V-type engine is such that the resonance annular passage 6 is formed in the space between the banks 1 and 2. 6a and 6b extend in parallel with each other along the cylinder arrangement direction and are arranged so as to be continuous with each other on both front and rear sides of the engine body. The upstream side portion and the downstream side portion of the resonance annular passage 6 are appropriately bent on the front and rear sides of the engine body. For example, the upstream side portion of the resonance annular passage 6 is bent along one end of the bank 2. Bent,
The outer side of the bank 2 is connected to the common intake passage 7, and the downstream communication portion 6c of the resonance annular passage 6 is folded back to the upper side. In this way, the resonance annular passage 6 and the like can be compactly incorporated into the engine body without increasing the overall height of the engine and without significantly protruding in the front-rear direction of the engine. In this case, the resonance annular passage 6 becomes sufficiently compact by forming a thin portion of the resonance annular passage 6 other than the intake air circulation path (the downstream side communication portion 6c).

The operation of the apparatus of this embodiment will be described with reference to FIG.

In the vicinity of each intake port of the same cylinder group whose intake order is not continuous, for example, in the vicinity of each intake port 4a-4c of the first cylinder group, each cylinder of the first cylinder group The basic pressure oscillation that becomes negative pressure during each intake stroke and becomes positive pressure at the end of the intake stroke (line A in Fig. 3).
Occurs. The pressure wave generated in the vicinity of the intake port of a certain cylinder is divided into two directions, that is, the upstream side and the downstream side from the intake port, and propagates so as to circulate around the resonance annular passage 6, respectively, and the resonance annular passage It makes a round around 6 and acts on the intake ports of other cylinders of the same group. In this case, since the resonance annular passage 6 does not have an expansion chamber, the pressure wave propagates without being inverted.

When the time period during which the pressure wave travels around the resonance annular passage 6 substantially coincides with the period τ of the basic pressure oscillation, that is, the entire length L ( When the relationship between the equivalent pipe length (including the influence of branch pipe volume) and the period τ is τ = L / a ...... a: speed of sound, as shown by the arrow in FIG.
The pressure wave generated in a and propagated in the resonance annular passage 6 overlaps with the pressure wave generated in the second cylinder 3b, and similarly, the second cylinder 3
The pressure wave propagated from b overlaps with the pressure wave generated in the third cylinder 3c, and the pressure wave propagated from the third cylinder 3c overlaps the first cylinder 3
It overlaps with the pressure wave generated in a. In this way, the first cylinder group
The pressure waves resonate between the cylinders of the second cylinder group and the pressure vibrations are strengthened as shown by the line B in FIG. 3, and similarly, the resonances of the cylinders of the second cylinder group also generate the pressure vibrations. . Due to this resonance effect, the filling efficiency of each cylinder is enhanced.

Although FIG. 3 shows a basic resonance state in which one pressure wave of the pressure oscillation occurring in the same cylinder group propagates so as to overlap with the next pressure wave, every other pressure wave is shown. A resonance state can be obtained even when propagating so as to overlap with every other two pressure waves. Therefore, a resonance state can be obtained even at an engine speed that is an integral multiple of the engine speed at which the above-described basic resonance state is obtained.

According to the intake device of the present invention which has the resonance effect by the resonance annular passage 6 as described above, the speed is higher than that of the structure having the pressure reversal portion on the upstream side without providing the communication passage on the downstream side. This is advantageous for improving the filling efficiency in the area.

That is, the passage leading to each intake port of the first cylinder group and the passage leading to each intake port of the second cylinder group are extended only on the upstream side. In the case where the collecting part is configured as a pressure reversing part, when the pressure wave reflected by reversing from negative pressure to positive pressure at the collecting part acts on the own cylinder and strengthens the pressure at the end of the intake stroke The filling efficiency is increased, and the relationship between the period τ of pressure oscillation and the passage length L ′ (equivalent pipe length) from the intake port to the collecting portion at this time is: 2 = 2L ′ / a. Since the cycle τ of the pressure oscillation becomes shorter as the engine speed becomes higher, it is necessary to set the passage length short in order to enhance the supercharging effect in the high speed range. There is a difference in the passage length from the passage to the passage collecting portion by the length between the intake ports of the cylinders, and the shorter the passage length to the collecting portion, the larger the difference becomes. Since the imbalance of the pressure wave acting on the cylinder becomes large, it becomes difficult to increase the overall charging efficiency.

On the other hand, according to the apparatus of the present embodiment, the resonance effect is obtained when the above equation is satisfied, and comparing this equation with the equation, if the period τ of pressure oscillation is the same,
The equivalent pipe length L of the entire resonance annular passage 6 is four times the equivalent pipe length L'in the case of the above expression, and the difference in the pressure wave propagation paths for each cylinder is relatively small even in the high speed region, so that it acts on each cylinder. The pressure wave unbalance becomes smaller. Therefore,
The filling efficiency can be effectively increased in the high speed range.

Further, in the resonance annular passage 6, since the downstream side communicating portion 6c, which is a portion other than the intake air circulation passage, is formed thin, the filling efficiency is further enhanced. That is, generally, when a pressure wave propagates through a passage, the pressure wave tends to be intensified as the passage area becomes smaller to some extent. However, in the resonance annular passage 6 through which the pressure wave is propagated, if the portion that also serves as a flow path for intake air is made thin, the intake air flow resistance increases and the introduction of intake air is hindered. Therefore, by thinning the portion other than the intake air flow path, the pressure wave is strengthened without disturbing the flow of the intake air, and the resonance effect is effectively enhanced. Actually, when the average effective pressures at various engine speeds were examined for the case where the downstream side communication portion 6c was thin and the case where the resonance annular passage 6 as a whole had a constant diameter, the resonance annular passage 6 as a whole had a diameter of 50 mm. When the diameter is constant (passage length is about 880 mm), the value connected by the broken line C is shown in FIG. 4, whereas when the diameter of the downstream side communication portion 6c is reduced to 40 mm, it is shown in FIG. The value connected with the solid line was, and the average effective pressure was increased.

According to the structure of the above embodiment, the intake air introduced from the common intake passage 7 is supplied to each cylinder through the upstream side portion of the resonance annular passage 6, but as shown in FIG. Most of the resonance annular passage 6 may be formed separately from the intake passage. That is, in this embodiment, the common intake passage 7 and the branch intake passages 7a, 7b branched from the passage 7 constitute a main intake system for introducing intake air, and the downstream ends of the branch intake passages 7a, 7b are formed. The portion is connected to the resonance annular passage 6 near the intake port. According to this structure, intake air introduced from the outside is supplied to each cylinder from the branch intake passages 7a, 7b only through the portion of the resonance annular passage 6 near the intake port. Therefore, neither of the communication portions 6c and 6d on both sides between the cylinder groups in the resonance annular passage 6 serves as a flow path for intake air, and only propagates a pressure wave.
In this case, the both communicating portions 6c and 6d may be formed thin.

FIG. 6 shows still another embodiment of the present invention, in which the passage length of the resonance annular passage 6 is variable. That is, in the downstream side communication portion 6c between the cylinder groups in the resonance annular passage 6, a short circuit communication portion 6e for short-circuiting the middle is provided.
Is provided with a first switching valve 11, and a second switching valve 12 is provided at a communication portion 6c downstream thereof. According to this structure, the first switching valve 11 is closed and the second switching valve 1 is closed.
Since the resonance annular passage 6 is relatively long when 2 is opened, and the substantial length of the resonance annular passage 6 is short when the first switching valve 11 is opened and the second switching valve is closed, Each switching valve 1 is controlled by an external control unit according to the engine speed.
By switching the opening and closing of 1 and 12, the resonance effect can be enhanced in different rotational speed regions. If the passage length is made variable as described above at the downstream side communication portion where the passage diameter is small, such a mechanism can be compactly incorporated.

FIG. 7 shows an embodiment in which the present invention is applied to an in-line three-cylinder engine. In this case, each cylinder 3
The a to 3c are not divided into two groups, and the intake ports 4a to 4c of the cylinders 3a to 3c arranged in series are connected to the resonance annular passage 6. And this resonance annular passage 6
Among them, a portion 6h that does not serve as an intake distribution path is formed thinner than the portions 6f and 6g that serve as a distribution path of intake air introduced from the common intake passage 7 into each of the cylinders 3a to 3c. Also in this case, the resonance effect is obtained between the cylinders by the resonance annular passage 6.

[0025]

As described above, according to the present invention, the intake passage communicating with the intake port of each cylinder does not have an expansion chamber and each intake port is not provided.
Since the resonance annular passage that circulates the pressure wave propagating from the inlet is provided, the pressure wave propagating from each intake port and making a full circle around the resonance annular passage effectively exerts a resonance effect on each cylinder. The filling efficiency can be improved. Moreover, since the expansion chamber is not necessary due to such a structure and the portion of the resonance annular passage other than the intake circulation passage is made thin, the intake system can be compactly incorporated into the engine, and the resonance The pressure wave propagating in the annular passage can be strengthened to enhance the resonance effect.

[Brief description of drawings]

FIG. 1 is a schematic view of an intake device showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a structure in which an intake system is incorporated in a V-type engine.

FIG. 3 is a diagram showing pressure oscillation near an intake port.

FIG. 4 is a graph of data obtained by examining average effective pressures at various engine speeds when the resonance annular passage has a constant diameter and when the portion other than the intake air circulation passage is made thin.

FIG. 5 is a schematic view of an intake device showing another embodiment of the present invention.

FIG. 6 is a schematic view of an intake device showing still another embodiment of the present invention.

FIG. 7 is a schematic view of an air intake device showing still another embodiment of the present invention.

[Explanation of symbols]

 3a to 3f Each cylinder 4a to 4f Intake port 6 Resonance annular passage 6a, 6b Intake supply passage 6c Communication part

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[Procedure amendment]

[Submission date] August 5, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Intake device for V-type engine

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a layout of an intake system for a V-type engine, which has a dynamic effect to enhance intake charging efficiency.

[0002]

2. Description of the Related Art Conventionally, various engine intake systems have been known which are designed to enhance the charging efficiency by the dynamic effect of intake air. For example, in a V-type engine, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 565, inertial supercharging is achieved by disposing an intake manifold having curved individual intake passages corresponding to branch portions and a space corresponding to an expansion chamber communicating with the individual intake passages. There is one that has an effect and enhances the filling efficiency. In addition, in the structure disclosed in this publication, the intake system is laid out between both banks of the V-type engine to reduce the overall size.

On the other hand, as a means of the dynamic effect, there is a method of increasing the filling efficiency by the resonance effect in addition to the above-mentioned inertial effect. For example, as shown in Japanese Patent Application Laid-Open No. 61-241418, the intake order is adjacent. There is a system in which a surge tank of two cylinder groups that do not match is formed with an annular intake passage that communicates with each other on the upstream side and the downstream side to perform resonance supercharging.

[0004]

According to the one disclosed in Japanese Patent Laid-Open No. 59-565, the intake manifold is laid out in the V bank to make it compact.
In order to have a resonance effect instead of the intake system, Japanese Patent Laid-Open No. Sho 61
The intake system as shown in Japanese Patent No. 241418 is V
When it is arranged between both banks of the type engine, the upstream and downstream communication pipes are lengthened, so that the protrusion amount in the engine cylinder row direction is significantly increased, which causes interference with other parts in the engine room. There was a problem that it could not contribute to the required compactness of the engine room.

In view of the above circumstances, the present invention makes it possible to effectively increase the charging efficiency by utilizing the dynamic supercharging, and at the same time, it is possible to lay out the intake system in a sufficiently compact intake system for a V-type engine. Is provided.

[0006]

The apparatus of the present invention is provided with a first intake supply passage for supplying intake air to a cylinder of one bank and an intake passage of the other bank for an intake passage communicating with an intake port of each cylinder of a V-type engine. An intake device for a V-type engine having an annular passage formed of a second intake supply passage that supplies intake air to a cylinder, an upstream communication portion that communicates both intake supply passages, and a downstream communication portion. The intake air supply passages are arranged between the banks so that the passage axial direction is substantially parallel to the cylinder row direction, and the downstream communication portion is bent with respect to the intake air supply passages. The downstream communication portion and both intake supply passages are arranged so as to vertically overlap with each other. An intake device for a V-type engine, which is characterized in that

[0007]

According to the above construction, the resonance effect is obtained between the cylinders by the pressure wave propagating through the annular passage. This annular passage is provided between both banks of the V-type engine, and the space between both banks is effectively used. In particular, since this annular passage has a downstream side communication portion that serves as a pressure wave propagation path but does not serve as an intake air circulation path, the downstream side communication portion is bent and the intake air passage and By arranging them so as to overlap with each other in the vertical direction, it is possible to obtain a compact structure while ensuring the output and avoiding the annular passage from largely protruding in the engine cylinder column direction.

[0008]

1 and 2 show an embodiment in which the device of the present invention is applied to a V-type 6-cylinder engine. 3 of 3
One cylinder 3a, 3b, 3c is provided, and the other bank 2
Has three cylinders 3d, 3e, 3f of No. 4, No. 5, No. 6
Is provided. The ignition order (intake order) of each cylinder is
For example, the first cylinder 3a, the fourth cylinder 3d, the second cylinder 3b,
The fifth cylinder 3e, the third cylinder 3c, and the sixth cylinder 3f are arranged in this order, and the cylinders 3a to 3c in one bank 1 constitute a first cylinder group in which the intake order is not continuous, and each cylinder in the other bank 2 The cylinders 3d to 3f form a second cylinder group in which the intake order is not continuous. Intake ports 4a to 4f and exhaust port 5a are provided in the cylinders 3a to 3f, respectively.
~ 5f are provided, and these intake ports 4a to 4f
The exhaust ports 5a to 5f are opened and closed at predetermined timings by an intake valve and an exhaust valve (not shown).

The intake ports 4a to 4f of each cylinder are connected to an annular passage 6 having no expansion chamber.
Is connected to a common intake passage 7 for introducing intake air through an air cleaner 8 and a throttle valve 9.

The annular passage 6 is connected to the intake ports 4a to 4c of one bank 1 via short branch pipes 10a to 10c to form a first intake supply passage 6a for supplying intake air to each cylinder of the bank 1. , Each intake port 4d of the other bank 2 ~
4f through the short branch pipes 10d to 10f, and the second intake supply passage 6b for supplying intake air to each cylinder of the bank 2.
And an upstream communication portion 6d and a downstream communication portion 6c.

Both of the intake air supply passages 6a and 6b extend in two directions, that is, an upstream side and a downstream side, and are connected to each other through the upstream side communicating portion 6d and the downstream communicating portion 6c on both sides thereof to form an annular shape. The upstream side communication portion 6d is connected to the common intake passage 7.

In the annular passage 6, a downstream side communication portion 6b which is a portion other than the intake air flow passage is formed thinner than a portion which becomes the intake air flow passage. That is, in the case of the present embodiment, in the annular passage 6, a portion to which each of the intake ports 4a to 4c of the one bank 1 and each of the intake ports 4d to 4f of the other bank 2 are respectively connected and an upstream communication portion (passage). A portion 6d where 6a and 6b extend to the upstream side and are continuous with each other is an intake passage through which intake air introduced from the common intake passage 7 into each of the cylinders 3a to 3f passes, but a downstream side communication portion (passage 6a, The portion 6c where 6b extends to the downstream side and is continuous with each other is out of the intake flow path, and almost no intake air flows. Therefore, the portion serving as the intake air flow passage is formed so as to have the passage area S ₁ required to reduce the intake resistance and secure the intake air flow rate, while the downstream side communication portion 6c is formed in the intake air flow passage. It is formed in the passage area S ₂ smaller than the portion to be.

By the way, although the passage structure of the intake system is schematically shown in FIG. 1, the actual layout incorporated in the V-type engine is as shown in FIG. In both the intake passages 6 of the annular passage 6,
a and 6b extend parallel to each other along the cylinder arrangement direction and are arranged so as to be continuous with each other on both front and rear sides of the engine body. The upstream side portion and the downstream side portion of the annular passage 6 are appropriately bent on both front and rear sides of the engine body. For example, the upstream side portion of the annular passage 6 is a bank 2 on one side.
Is connected to the common intake passage 7 at the outer side of the bank 2 by being bent along the end of the bank. On the other hand, the downstream communication portion 6c of the annular passage 6 is folded back upward so as to vertically overlap the intake air supply passages 6a and 6b.

According to the intake device of this embodiment,
The annular passage 6 has a resonance effect as will be described later, and the engine output is increased. In addition, the annular passage 6 and the like can be compactly incorporated into the engine body without increasing the overall height of the engine and significantly protruding in the front-rear direction of the engine.

That is, the annular passage 6 is disposed between the banks 1 and 2 and both intake supply passages 6a and 6b are provided.
Extend in parallel to the cylinder row direction, but the downstream side communication portion 6c is folded back so as to vertically overlap with the intake air supply passages 6a and 6b, so that the annular passage is outward in the cylinder row direction of the engine. The end portion of 6 is prevented from significantly protruding. Further, since the downstream side communication portion 6c is bent in a folded shape, it does not significantly project upward. Further, as in this embodiment, the downstream side communication portion 6c
If it is formed into a thin shape, it can be made more compact in the up-down direction in the bent state as described above.

The downstream side communication portion 6c serves as a pressure wave propagation path but not as an intake air flow path. Therefore, even if it is bent as described above, the intake resistance is not increased. Absent. Therefore, the annular passage 6 is provided in the space between the banks 1 and 2 while ensuring the engine output.
Will be laid out compactly. It should be noted that the intake air supply passages 6 do not have an intake expansion chamber, so that the intake air can be made compact.

Next, the operation of improving the output by the resonance effect in the case of the apparatus of this embodiment will be described with reference to FIG.

In the vicinity of each intake port of the same cylinder group in which the intake order is not continuous, for example, near each intake port 4a to 4c of the first cylinder group, a negative pressure occurs in the middle of each intake stroke due to the operation of each cylinder of the first cylinder group. A basic pressure oscillation (line A in FIG. 3) that becomes a positive pressure at the end of the intake stroke is generated. The pressure wave generated near the intake port of a cylinder is
It propagates so as to circulate around the annular passage 6 separately from the intake port in two directions, that is, upstream and downstream, and travels around the annular passage 6 substantially to act on the intake ports of other cylinders in the same group. In this case, since the annular passage 6 has no expansion chamber, the pressure wave propagates without inversion.

When the time when the pressure wave travels around the annular passage 6 substantially coincides with the period τ of the basic pressure oscillation, that is, the entire length L of the annular passage 6 (such as the branch pipe volume). (Equivalent pipe length in consideration of the influence of the above) and the above-mentioned period τ is τ = L / a ... a: when the sound velocity is reached, as shown by the arrow in FIG.
, The pressure wave that has propagated through the annular passage 6 overlaps with the pressure wave that has occurred in the second cylinder 3b, and the pressure wave that has similarly propagated from the second cylinder 3b overlaps with the pressure wave that has generated in the third cylinder 3c.
The pressure wave propagated from the third cylinder 3c overlaps with the pressure wave generated in the first cylinder 3a. In this way, the pressure waves resonate between the cylinders of the first cylinder group and the pressure vibrations are intensified as shown by the line B in FIG. 3, and similarly, the resonances also occur between the cylinders of the second cylinder group and the pressure vibrations occur. Be strengthened. Due to this resonance effect, the filling efficiency of each cylinder is enhanced.

Note that FIG. 3 shows a basic resonance state in which one pressure wave of pressure oscillation generated in the same cylinder group propagates so as to overlap with the next pressure wave.
A resonance state is obtained even when propagating so as to overlap with every other pressure wave or every two pressure waves. Therefore, a resonance state can be obtained even at an engine speed that is an integral multiple of the engine speed at which the above basic resonance state is obtained. To be

According to the intake device having the resonance effect by the annular passage 6 as described above, the filling efficiency in the high speed region is higher than that in the structure having the pressure reversal portion on the upstream side without providing the downstream communication path. It is advantageous for improvement.

That is, with the passage leading to each intake port of the first cylinder group and the passage leading to each intake port of the second cylinder group extending only upstream, the collective portion of these two passages serves as a pressure reversal portion. In the case of the structure, the charging efficiency is increased when the pressure wave reflected by reversing from the negative pressure to the positive pressure at the collecting portion acts on the own cylinder to strengthen the pressure at the end of the intake stroke. At this time, the relationship between the period τ of pressure oscillation and the passage length L ′ (equivalent pipe length) from the intake port to the collecting portion is τ / 2 = 2L ′ / a. Since the cycle τ of the pressure oscillation becomes shorter as the engine speed becomes higher, it is necessary to set the passage length short in order to enhance the supercharging effect in the high speed range. The passage length to the gathering portion has a difference corresponding to the length between the intake ports of the cylinders. The shorter the passage length to the gathering portion is, the larger the difference becomes, and the difference acts on each cylinder. Since the imbalance of the pressure wave becomes large, it becomes difficult to increase the overall filling efficiency.

On the other hand, according to the apparatus of the present embodiment, the resonance effect is obtained when the above equation is satisfied, and comparing this equation with the equation, if the period τ of pressure oscillation is the same,
The equivalent pipe length L of the entire annular passage 6 is four times the equivalent pipe length L ′ in the case of the above equation, and the difference in the pressure wave propagation paths for each cylinder is relatively small even in the high speed range, so that the pressure wave acting on each cylinder is The unbalance of is reduced. Therefore, the filling efficiency can be effectively increased in the high speed range.

Further, in the annular passage 6, the downstream side communicating portion 6c, which is a portion other than the intake air flow passage, is formed thin, so that the filling efficiency is further enhanced. That is, generally, when a pressure wave propagates through a passage, the pressure wave tends to be intensified as the passage area becomes smaller to some extent. However, in the annular passage 6 through which the pressure wave is propagated, if the portion that also serves as the intake air passage is made thin, the intake air flow resistance increases and the intake air is blocked. Therefore, by thinning the portion other than the intake air flow path, the pressure wave is strengthened without disturbing the flow of the intake air, and the resonance effect is effectively enhanced.
Actually, when the average effective pressure at various engine speeds was examined for the case where the downstream side communication portion 6c is thin and the case where the entire annular passage 6 has a constant diameter, the entire annular passage 6 has a constant diameter of 50 mm (passage). When the length is set to about 880 mm), the value is connected by the broken line C in FIG. 4, whereas when the downstream side communication portion 6c is thinned to a diameter of 40 mm, it is connected by a solid line in FIG. The average effective pressure was increased.

According to the structure of the above embodiment, the intake air introduced from the common intake passage 7 is supplied to each cylinder through the upstream portion of the annular passage 6, but as shown in FIG.
Type first engine, first and second intake air supply passages 6a, 6b for supplying intake air to the cylinders of each bank 1, 2 and communication portions 6 on both sides thereof
Most of the annular passage 6 composed of c and 6c ′ may be formed independently of the passage for introducing the intake air. That is, in this embodiment, the common intake passage 7 and the passages 7 to 2
A main intake system for introducing intake air is constituted by the branch intake passages 7a and 7b that are branched off.
Is connected to the annular passage 6 near the intake port. According to this structure, the intake air introduced from the outside,
It is supplied to each cylinder from the branch intake passages 7a and 7b only through the portion of the annular passage 6 near the intake port. Therefore, neither of the communicating portions 6c, 6c 'on both sides between the cylinder groups in the annular passage 6 serves as a flow path for intake air, and only propagates the pressure wave.

Also in the case of this embodiment, the passage structure is schematically shown in FIG. 5, but the layout when incorporated in a V-type engine is such that the intake air supply passages 6a and 6b are provided between the banks 1 and 2. Are arranged in parallel with the cylinder row direction, and the communicating portions that do not serve as the intake passage are folded back so as to vertically overlap the intake supply passages 6a and 6b. For example, both the communicating portions 6c and 6c 'on both sides are both supplied to the intake air. It may be folded back on the passages 6a and 6b. Furthermore, the above-mentioned both-side communicating portions 6c and 6d may be formed thin.

With this layout, the engine can be made compact in the front-rear direction and the up-down direction, as in the first embodiment.

FIG. 6 shows still another embodiment of the present invention,
In this embodiment, the passage length of the annular passage 6 is variable. That is, the intake supply passage 6a in the annular passage 6,
A downstream side communication portion 6c that communicates the downstream side of 6b is provided with a short-circuit communication portion 6e that short-circuits the middle thereof. The short-circuit communication portion 6e is provided with a first switching valve 11 and a communication portion 6c downstream thereof. The second switching valve 12 is provided in the. According to this structure, the annular passage 6 is relatively long when the first switching valve 11 is closed and the second switching valve 12 is opened, and the annular passage 6 is annular when the first switching valve 11 is opened and the second switching valve 12 is closed. Since the substantial length of the passage 6 is shortened, the control valve (not shown) controls the switching valves 1 according to the engine speed.
By switching the opening and closing of 1 and 12, the resonance effect can be enhanced in different rotational speed regions.

Also in the case of this embodiment, the passage structure is schematically shown in FIG. 6, but the layout when incorporated in the V-type engine is such that the intake air supply passages 6a and 6b are provided between the banks 1 and 2. Are arranged in parallel to the cylinder row direction, and the downstream side communication portion 6c is connected to the intake supply passage 6
By being folded back so as to vertically overlap with a and 6b, the compactness of the engine front-rear direction and the up-down direction can be achieved. Furthermore, the passage diameter of the downstream side communication portion 6c is reduced,
If the passage length is made variable in this part as described above,
A mechanism for changing the passage length can be compactly incorporated.

In the above embodiment, the annular passage 6 does not have the expansion chamber, but it may be applied to the annular passage having the expansion chamber.

Further, in the above embodiment, the passage area of the downstream side communication portion 6c of the annular passage 6 which is bent in a folded shape is made smaller than the passage areas of the other portions, but the downstream side communication is made. The part may have the same passage area as other parts.

[0032]

As described above, according to the present invention, since the intake passage communicating with the intake port of each cylinder is provided with the annular passage, the filling efficiency can be enhanced by the resonance effect. Moreover,
Such an intake system is arranged between both banks of the V-type engine, and in particular, the downstream side communication portion of the annular passage, which does not serve as an intake passage, is laid out so as to be vertically overlapped with the intake supply passage. Therefore, while securing the output, it is possible to prevent the annular passage from significantly protruding outward in the cylinder column direction, and to obtain a compact intake device.

[Brief description of drawings]

FIG. 1 is a schematic view of an intake device showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a structure in which an intake system is incorporated in a V-type engine.

FIG. 3 is a diagram showing pressure oscillation near an intake port.

FIG. 4 is a graph showing data obtained by examining average effective pressures at various engine speeds when the annular passage has a constant diameter and when the portion other than the intake air flow passage is made thin.

FIG. 5 is a schematic view of an intake device showing another embodiment of the present invention.

FIG. 6 is a schematic view of an intake device showing still another embodiment of the present invention.

[Explanation of Codes] 3a to 3f Each cylinder 4a to 4f Intake port 6 Annular passages 6a and 6b Intake supply passage 6c Communication part

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─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location F02M 35/116 (72) Inventor Yasuhiro Yuzuka Shinchi Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation Within

Claims (3)

[Claims] 1. A first intake supply passage for supplying intake air to a cylinder of one bank and an intake passage for supplying intake air to a cylinder of the other bank to an intake passage communicating with an intake port of each cylinder of a V-type engine. A resonance annular passage, which is formed of an intake air supply passage and an upstream communication portion and a downstream communication portion that connect the intake air supply passages to each other, is formed in an annular shape so as to circulate a pressure wave propagating from each intake port. An intake device for a type engine, wherein the both intake supply passages are arranged between both banks so that the passage axial direction is parallel to the cylinder row direction, and the downstream side communication is performed with respect to the both intake supply passages. An intake device for a V-type engine, characterized in that the portion is bent so that the downstream communication portion and both intake supply passages are vertically overlapped. 2. The intake system for a V-type engine according to claim 1, wherein both of the intake supply passages have no intake expansion chamber. 3. The downstream side communicating portion is formed to be thinner than both of the intake air supply passages, and this portion is bent.
Alternatively, the intake device for the V-type engine according to item 2.