JP2905930B2 - Engine intake system - Google Patents

Description

The present invention relates to an intake device for a multi-cylinder engine.

(Prior Art) In recent engines, dynamic effects of intake air, particularly inertial supercharging, are increasing. When performing this inertia supercharging, the surge tank and each cylinder are connected by independent independent intake passages, and this surge tank is used as a pressure reversal unit. And
The longer the length of the independent intake passage from each cylinder to the pressure reversing section, the lower the rotational speed at which inertial supercharging is obtained.

Further, as disclosed in Japanese Patent Application Laid-Open No. Sho 62-210219, for example, by switching between a relatively short intake passage and a relatively long intake passage, inertia excess occurs in both the low speed range and the high speed range of the engine. There has also been proposed an intake device that supplies air and thereby obtains a high flat output torque over a wide rotation range. As an example, while providing a volume chamber for communicating the middle part of the independent intake passage with each other,
The length of the intake passage between the intake port and the pressure reversing section is changed by controlling the opening and closing of a shutter valve provided between the volume chamber and each independent intake passage in accordance with the engine speed. ing.

(Object of the Invention) It is an object of the present invention to provide an intake device for an engine that improves the volumetric efficiency of intake air at the time of high rotation when performing the above-described inertial supercharging.

(Structure of the Invention) In the intake device for an engine according to the present invention, the intake air supplied to the surge tank via the centralized intake passage upstream of the surge tank inlet connects the surge tank to the intake port of each cylinder. In the intake device for an engine configured to be supplied to each cylinder via the engine, a mode in which a volume chamber communicating with each independent intake passage downstream of the outlet of the surge tank at the time of high engine rotation partially overlaps with the centralized intake passage is provided. And a bypass passage that directly communicates the centralized intake passage and the volume chamber is provided in the overlapping portion.

In this case, a shutter valve is provided between the independent intake passage and the volume chamber. The shutter valve opens when the engine rotates at a high speed to communicate the independent intake passage with the volume chamber, and at the same time when the engine rotates at a low speed. Further, it is preferable that the independent intake passage be closed at the time of medium rotation so as not to communicate with the volume chamber.

(Effects of the Invention) In the present invention, at the time of high engine rotation, at the output downstream of the surge tank, a bypass passage that directly communicates a volume chamber that forms a pressure reversal part by communicating with each independent intake passage and a centralized intake passage is provided. Since the intake air enters the volume chamber from the centralized intake passage through the bypass passage at the time of high rotation, it is supplied from this volume chamber to the downstream portion of the independent intake passage, and merges with the intake air passing through the surge tank. The volumetric efficiency of the intake air during rotation can be improved.
In addition, in the present invention, since the bypass passage is provided at the overlapping portion of the centralized intake passage and the volume chamber, the length of the bypass passage can be made extremely short, thereby further reducing the intake resistance of the bypass passage. It is possible to reduce the pressure and improve the intake efficiency.

(Embodiment) Hereinafter, an embodiment in which the intake device according to the present invention is applied to a V-type 12-cylinder engine will be described with reference to the drawings.

1 is a partial cross-sectional plan view of the intake manifold assembly, and FIG. 2 is a partial cross-sectional front view showing the intake manifold assembly of FIG.
1L, 1R are the left and right banks of engine E, each bank 1L, 1R
Has six cylinders in series, and the right bank 1R is offset rearward (upward in FIG. 1) by a predetermined dimension with respect to the left bank 1L. The intake manifold assembly 2 has a two-bore throttle body 3 at the most upstream end. The throttle body 3 is disposed substantially at the center between the left and right banks 1L and 1R, and opens forward (downward in FIG. 1) with the rear (upper side in FIG. 1) as an intake outlet. Left bore 4L for bank 1L and right bank 1R
The right bore 4R is provided independently and in parallel.

A normally-open throttle electrically operated in the closing direction by DC motors 6L and 6R mounted on the left and right outer walls of the throttle body 3 via reduction mechanisms 5 respectively in the bores 4L and 4R of the throttle body 3. The valves 7L and 7R and the normally-closed throttle valves 8L and 8R that are mechanically operated in the opening direction by depressing an accelerator pedal are electrically operated throttle valves 7L and 7R.
Are arranged on the upstream side, respectively (see FIG. 3). The four throttle valves 7L, 7R and 8L, 8R are all rotated about a horizontal axis in the left-right direction. In this case, as is clear from FIG. 1, the mounting positions of the motors 6L, 6R are provided so as to be offset in the front-back direction corresponding to the mutual offset amount and the offset direction of the left and right banks 1L, 1R. Accordingly, the left and right electric throttle valves 7L, 7R are also offset from each other in the front-rear direction. Motors 6L and 6R themselves are also throttle valves.
The throttle body 3 is offset rearward with respect to 7L and 7R, and is located near the center of the throttle body 3 in the front-rear direction. In addition, as shown in FIG. 3, the throttle body 3 has a front portion provided with the electric throttle valves 7L and 7R in a forward and downward direction in accordance with the inclination angle of the bonnet 9 as a countermeasure against a lower bonnet of the vehicle body. Accordingly, the axes of the front portions of the passages 4L and 4R are also inclined forward and downward.

Above the left and right banks 1L, 1R, a pair of left and right elongated surge tanks 10L, 10R extending in the front-rear direction (crankshaft direction).
These surge tanks 10L, 10R are connected to the throttle body 3 by a pair of left and right upstream intake manifolds 11L, 11R derived from the rear end of the throttle body 3.

The left upstream intake manifold 11L forms a collective intake passage 12L that curves leftward from the rear end of the left passage 4L of the throttle body 3, and branch intake passages 13L and 14L that are branched from the collective intake passage 12L. 13L, 14L branch intake passage
The downstream end of the left surge tank 10L communicates with the inside of the left surge tank 10L through openings 15, 16 spaced apart from each other in the front wall of the left surge tank 10L. Similarly, the right upstream intake manifold 11R includes a collective intake passage 12R that curves rightward from the rear end of the right passage 4R of the throttle body 3;
A branch intake passage 13R branched from the collective intake passage 12R,
14R, and the downstream ends of the branch intake passages 13R and 14R are provided with openings 15 and 16 spaced apart in the front-rear direction on the top wall of the right surge tank 10R, respectively. It communicates with the inside. Collective intake passages 12L, 12
Openings 17 for recirculating to the blow-by gas intake system are formed at the bottom of the R, respectively. From the rear ends of the upstream intake manifolds 11L and 11R, a communication volume chamber 25 described later is provided.
The pipes 18 for forming the bypass passages 33L and 33R respectively communicating with L and 25R are respectively led out integrally so as to face the intake and discharge ports of the throttle body 3. The throttle body 3 and the left and right upstream intake manifolds 11L and 11R are integrally formed, and the bifurcated downstream ends of the upstream intake manifolds 11L and 11R can be attached to and detached from the top walls of the left and right surge tanks 10L and 10R, respectively. It can be attached to.

Below the upstream intake manifolds 11L and 11R, there are disposed downstream intake manifolds 19L and 19R integrally formed with the surge tanks 10L and 10R, respectively. The left downstream intake manifold 19L includes six independent intake passages 21a to 21f that respectively connect the intake ports 20L of the six cylinders provided in the left bank 1L and the left surge tank 10L from the front. At the downstream end of the downstream intake manifold 19L, this downstream intake manifold 19L is connected to the cylinder head 2 of the left bank 1L.
A flange portion 23 for fixing to 2L is formed. Of the six independent intake passages 21a to 21f, three forward independent intake passages 21a to 21c are connected to the front part of the left surge tank 10L in close proximity to each other, and three independent independent intake passages on the rear side. 21d to 21f are connected to the rear part of the left surge tank 10L in close proximity to each other, and form a space for accommodating the motor 6L in the form of being dropped in the center. Similarly, the right downstream intake manifold 19R includes six independent intake passages 21g to 21l that respectively connect the intake ports 20R of the six cylinders provided in the right bank 1R and the right surge tank 10R. At the downstream end of the downstream intake manifold 19R, a flange portion 23 for fixing the manifold 19R to the cylinder head 22R of the right bank 1R is formed. The three independent intake passages 21g to 21i on the front side are connected close to each other to the front part of the right surge tank 10R, and the three independent intake passages 21j to 21l on the rear side are connected to the rear part of the right surge tank 10R. To form a space for accommodating the motor 6R in the form of being dropped in the center. Fuel injection valves 24 are attached to the flange portions 23 of the downstream intake manifolds 19L and 19R so as to face the independent intake passages 21a to 21l.

Between the left downstream intake manifold 19L and the left bank 1L, there is provided an elongated communication volume chamber 25L formed integrally with the downstream intake manifold 19L and extending in parallel with the surge tank 10L. This volume chamber 25L and each independent intake passage 21a ~
As shown in FIG. 2, each of the communication passages 21f communicates with a corresponding one of the communication passages 21f via a short communication passage 27. Each communication passage 27 is provided with a shutter valve 28. These shutter valves 28
It is attached to a common operating shaft 29L extending over the entire length of L, and is simultaneously rotated by an actuator 30L. As described later, these shutter valves 28
It functions for switching the tuning speed of inertia supercharging. A pipe 31 extends from the rear end of the volume chamber 25L. This pipe 31 is connected via a connecting pipe 32 to a pipe 18 derived from the rear end of the upstream intake manifold 11L, thereby forming a bypass passage 33L for communicating the collective intake passage 12L and the volume chamber 25L. I have.

Similarly, the right downstream intake manifold 19R and the right bank 1
An elongated communication volume chamber 25R formed integrally with the downstream intake manifold 19R and extending in parallel with the surge tank 10R is provided between the surge tank 10R and the downstream intake manifold 19R. The communication tank 25R and each of the independent intake passages 21g to 21l communicate with each other via a short communication passage 27, and a shutter valve 28 is provided in each of the communication passages 27, and is operated by an actuator 30R. Are mounted on the operating shaft 29R and are operated simultaneously. A pipe 31 is also drawn out from the rear end of the communication tank 25R, and this pipe 31 is connected to a pipe 18 drawn out from the rear end of the upstream intake manifold 11R via a connecting pipe 32, whereby the collective intake passage 12R A bypass passage 33R is formed, which communicates with the volume chamber 25R.

On the other hand, in each of the surge tanks 10L and 10R, an opening / closing valve 34 for switching the tuning speed of resonance supercharging operated by an actuator (not shown) is provided at an intermediate portion in the crankshaft direction (front-back direction). I have. And these on-off valves
When the valve 34 is opened, one chamber is formed in the surge tanks 10L and 10R over their entire lengths, whereby the left independent intake passages 21a to 21f communicate with each other in the left surge tank 10L. , And each independent intake passage 2 on the right
1g to 21l communicate with each other in the right surge tank 10R.
On the other hand, when the on-off valve 34 is closed, the surge tank
Two chambers 10a and 10B are defined in 10L and 10R. That is, in the left surge tank 10L, three chambers 10a
The two independent intake passages 21a to 21c communicate with each other and the other chamber 10b
Thus, the three independent intake passages 21d to 21f communicate with each other.
Then, the intake air is supplied to the one chamber 10a thus defined from the branch intake passage 13L through the opening 15, and the intake air is supplied to the other chamber 10b from the branch intake passage 14L through the opening 16. The right surge tank 10R has the same relationship as described above.

Further, a volume chamber 35L is provided below the independent intake passages 21b to 21e and between the left surge tank 10L and the cylinder head 22L of the left bank 1L. The outer wall of this volume chamber 35L is formed integrally with the left surge tank 10L in contact with the inner wall of the left surge tank 10L, and the chambers 10a and 10
b communicate with each other through the volume chamber 35L. Similarly, on the right bank 1R side, a similar volume chamber 35R is provided in a similar relationship.

In the volume chambers 35L and 35R, an on-off valve 36 for switching the tuning speed of resonance supercharging, which is operated by an actuator (not shown), at an intermediate portion in the crankshaft direction (front-back direction).
Are arranged. The lengths of the volume chambers 35L and 35R are shorter than the lengths of the branch intake passages 13L and 14L and 13R and 14R.

Next, the dynamic effect of intake air accompanying the operation of the shutter valve 28 and the opening / closing valves 34 and 36 will be described. However, the ignition order of each cylinder is set under the following conditions. That is, the cylinders connected to the independent intake passages 21a to 21c are not adjacent to each other in the ignition order, and the cylinders connected to the independent intake passages 21d to 21f are not adjacent to each other in the ignition order. The cylinders to which the passages 21g to 21i are connected are not adjacent to each other in the ignition order,
The cylinders connected to the independent intake passages 21i to 21l are not adjacent to each other in the ignition order.

(1) When the engine speed is 3500 rpm or less, each valve 2
8, 34 and 36 are all closed. As a result, resonance supercharging is performed in which the upstream portions of the branch intake passages 13L, 14L and 13R, 14R are pressure reversing portions.

(2) When the engine speed is in the range of 3500-4500 rpm, valve 2
8 and 34 are closed, and only the valve 36 in the chambers 35L, 35R is opened. Thus, resonance supercharging is performed using the volume chambers 35L and 35R as resonance paths.

(3) When the engine speed is in the range of 4500 to 5500 rpm, 12
Only one shutter valve 28 is closed and valves 34 and 36 are opened. As a result, inertial supercharging is performed using the surge tanks 10L and 10R as pressure reversing sections.

(4) When the engine speed exceeds 5500 rpm, all valves 28, 34 and 36 are opened. As a result, inertia supercharging is performed with the volume chambers 25L and 25R as pressure reversing portions, respectively, and the shutter valve 28 is opened, so that the intake air flows from the common intake passages 12L and 12R through the bypass passages 33L and 33R and the volume chambers. After entering 35L and 35R, they are further supplied to the independent intake passages 21a to 21l through the communication passage 27, and the supercharging efficiency is further improved.

As is apparent from the above description, according to the present embodiment, at the time of high-speed rotation (5500 rpm or more), the volume chambers 25L and 25R forming the pressure reversal part by opening the shutter valve 28 and the centralized intake passage 12
Short bypass passages 33L, 33R communicating L and 12R respectively
Is provided, and the pipe 18 for forming the bypass passages 33L and 33R is provided at a position facing the intake discharge port of the throttle body 3, so that when the shutter valve 28 is opened during high-speed rotation, the intake air is From the centralized intake passages 12L and 12R, they directly enter the volume chambers 25L and 25R through the bypass passages 33L and 33R, are supplied to the downstream portions of the respective independent intake passages 21a to 21l, and are merged with the intake air via the surge tanks 10L and 10R. Therefore, it is possible to improve the volumetric efficiency of intake air at the time of high rotation.

In this embodiment, the outlet of the blow-by gas passage for returning the blow-by gas to the intake system is connected to the common intake passage 12.
Openings 17 are provided in L and 12R. Since the blow bath gas contains fuel and oil, there is a demand to distribute the gas evenly to each cylinder in order to prevent variations in the air-fuel ratio when the gas is returned to the intake system. Therefore, by returning the air to the intake system from the openings 17 of the common intake passages 12L and 12R as described above, the distribution of the blow-by gas can be improved. For the same reason, although not shown, it is preferable to provide outlets of the EGR passage for recirculating a part of the exhaust gas to the intake system in the common intake passages 12L and 12R.

Further, in the present embodiment, the left downstream intake manifold 19 is provided.
In L, a space is provided between the front three independent intake passages 21a to 21c and the rear three independent intake passages 21d to 21f,
In the right downstream intake manifold 19R, a space is provided between the three independent intake passages 21g to 21i on the front side and the three independent intake passages 21j to 21l on the rear side, and a motor for driving the throttle valves 7L and 7R is provided. Since the 6L and 6R are attached to the throttle body 3 with offsets corresponding to the offset amounts and the offset directions of the left and right banks 1L and 1R, the ideal arrangement is such that the throttle body 3 is provided substantially at the center between the left and right banks 1L and 1R. While securing the downstream intake manifold
Motor 6L, 6R using the space formed in 19L, 19R
Can be arranged, whereby the intake device can be made compact and the entire engine can be made compact.

Also, the electric throttle valves 7L and 7R driven by the motors 6L and 6R are arranged upstream of the mechanical throttle valves 8L and 8R, so that the downstream end of the throttle body 3 is connected to the left and right surge tanks 10L and 10R. Collective intake passages 12L, 12R and branch intake passages 13L, 13R, 14L, 14R
The motors 6L and 6R can be arranged with a sufficient space without being hindered by the space.

Furthermore, according to the present embodiment, the heavy motors 6L and 6R are disposed so as to be deviated toward the center of the throttle body 3 in the front-rear direction with respect to the throttle valves 7L and 7R, so that the center of gravity of the throttle body 3 is set at the center. Part can be approached,
Thereby, mechanical support of the throttle body 3 can be facilitated, and reliability of the throttle body 3 can be improved.

Further, according to the present embodiment, as is apparent from FIG. 3, the portion where the electric throttle valves 7L and 7R of the throttle body 3 are disposed is inclined forward and downward, so that the bonnet of the vehicle body is reduced. Becomes easier.

Further, in the present embodiment, the volume chambers 35L and 35R each provided with the on-off valve 36 for switching the tuning speed of the resonance supercharging are provided below the independent intake passages 21a to 21f and 21g to 21l, respectively, and in the surge tank.
Between 10L and cylinder head 22L and surge tank 10R
And the cylinder head 22R, the space can be effectively used, and the vibration of the intake system can be suppressed.

Although not shown in the drawings, by further providing a communication path for communicating the left and right volume chambers 25L and 25R serving as pressure inversion portions at a central portion thereof at the time of high-speed rotation, the intake air when the shutter valve 28 is opened is provided. Reduced resistance and left and right banks
The variation of the air-fuel ratio between 1L and 1R can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional plan view showing an intake manifold assembly according to one embodiment of the present invention, FIG. 2 is a partial cross-sectional front view showing the intake manifold assembly of FIG. 1 attached to an engine, and FIG. FIG. 3 is a sectional view of a throttle body. 1L, 1R… left and right bank 2… intake manifold assembly 3… throttle body 4L, 4R… throttle body bore 6L, 6R… motor 7L, 7R… electric throttle valve 8L, 8R… mechanical throttle Valve 10L, 10R …… Surge tank 11L, 11R …… Upstream intake manifold 12L, 12R …… Combined intake passage 13L, 13R, 14L, 14R… Branch intake passage 19L, 19R …… Downstream intake manifold 21a-21l …… Independent Inlet passage 25L, 25R… Volume chamber 28… Shutter valve 33L, 33R… Bypass passage 34, 36… On-off valve 35L, 35R… Volume chamber

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Moto Aoki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Pref. Inside Mazda Co., Ltd. (56) References Japanese Utility Model Application Sho 63-191239 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) F02B 27/02 F02M 35/104

Claims (2)

(57) [Claims] An intake air supplied to the surge tank via a centralized intake passage upstream of a surge tank inlet is supplied to each cylinder via an independent intake passage connecting the surge tank to an intake port of each cylinder. In the intake device for an engine configured as described above, a volume chamber communicating with each independent intake passage downstream of the outlet of the surge tank at the time of high engine rotation is arranged close to the centralized intake passage so as to partially overlap with the centralized intake passage. An intake device for an engine, wherein a bypass passage that directly communicates the centralized intake passage and the volume chamber is provided in the overlapping portion. 2. A shutter valve is provided between the independent intake passage and the volume chamber. The shutter valve opens when the engine rotates at a high speed to communicate the independent intake passage with the volume chamber. 2. The intake system for an engine according to claim 1, wherein the intake system is configured to be closed at the time of rotation and medium rotation so as not to communicate the independent intake passage with the volume chamber.