JP2832041B2 - Engine intake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application >> The present invention relates to a low-speed intake passage having a long path length and a low-speed intake passage for introducing intake air into an intake port of each cylinder in accordance with an operating state of an engine. The present invention relates to an intake device for an automobile engine, which is appropriately switched to a high-speed intake passage having a short length.
In particular, the present invention relates to an intake device for an engine having an improved on-off valve for switching an intake passage.

<< Prior Art >> Conventionally, as this kind of intake device, there is one disclosed in Japanese Patent Application Laid-Open No. 62-162723.

The proposed intake device forms an intake passage for introducing intake air into each cylinder of a multi-cylinder engine into a high-speed intake passage having a short path length and a low-speed intake passage having a long path length. The high-speed intake passage and the low-speed intake passage are integrated and arranged in front of the intake port of each cylinder, and each high-speed intake passage is provided with an on-off valve that closes this passage in the low-speed rotation range of the engine. It becomes.

In the low-speed operation range of the engine, the high-speed intake passage is closed by an on-off valve, and intake air is introduced into the intake port of each cylinder via a long-path low-speed intake passage. In this case, the high-speed intake passage is opened, and the intake air is introduced into each of the intake ports from the low-speed intake passage as well as the high-speed intake port having a short path length. In other words, in this high-speed operation range, most of the intake air amount charged into the cylinder is introduced into the intake port of each cylinder from above one of the banks through the high-speed intake passage, and partly from above the other bank. It is introduced through a low speed intake passage. That is, the intake passage communicating with the intake port is switched in accordance with the operating speed of the engine, whereby the engine operation is optimized.

<< Problems to be Solved by the Invention >> In the above-described intake device, the high-speed intake passage and the low-speed intake passage are integrated before the intake port of each cylinder. Conventionally, there has not been known a suitable opening / closing valve for switching an intake passage for an intake device configured to integrate two intake passages. That is, although the prior art discloses that the on-off valve of the high-speed intake passage is provided on the side of the branch from the low-speed intake passage, when such an on-off valve arrangement structure is applied,
When the high-speed intake passage is closed, the flow passage cross-sectional area of the low-speed intake passage changes abruptly at the integrated portion, and turbulence is generated in the relevant portion, and the smooth flow of intake is hindered. There is a possibility that torque fluctuations may occur in an engine low-speed operation range in which intake is performed via an intake passage.

The present invention has been made in view of such circumstances, and an object thereof is to reduce turbulence generated in an integrated portion with a high-speed intake passage during low-speed operation of an engine in which intake air is introduced from a low-speed intake passage. , The smooth intake can be achieved, the intake efficiency can be further improved, and the occurrence of torque fluctuation due to the turbulence of the intake flow in the low-speed operation range can be prevented as much as possible. An engine intake device is provided.

<< Means for Solving the Problems >> In order to achieve the above object, claim 1 according to the present invention.
In the intake device for an engine described above, a first passage having a short path length through which intake air to be introduced into each cylinder is introduced during high-speed operation, and intake air introduced into each cylinder during low-speed operation, flow through an intake passage of a multi-cylinder engine. It branches into a curved second passage having a long path length, and the first passage and the second passage are integrated and juxtaposed before each cylinder, and the first passage is provided in the first passage portion. An on-off valve that opens in a high-speed rotation range of the engine and closes in a low-speed rotation range is provided. The on-off valve is brought close to an integrated portion with the second passage, and is closed to the second passage when the first passage is closed. The facing side faces are arranged along the streamline direction of the second passage, and the second passage has a two-tiered configuration.

<< Operation >> According to the intake system for an engine according to the present invention, the first passage is closed by the on-off valve in the low-speed operation range of the engine, so that intake air is introduced into each cylinder from the throttle body through the second passage having a long path length. Is done.

At this time, since the side surface of the on-off valve facing the second passage is arranged along the streamline direction of the second passage, the second
The flow path cross-sectional area of the passage does not significantly change at the integrated portion, and turbulence is suppressed as much as possible. Therefore, in the low-speed engine operation region in which intake is performed through the second passage, smooth intake can be achieved, and the intake efficiency can be further improved, so that torque fluctuation can be prevented as much as possible.

On the other hand, in the high-speed operation range, the on-off valve of the first passage is opened,
The on-off valve projects into the second passage. At this time, most of the intake air is introduced into each cylinder through the first passage having a short path length, and part of the intake air is introduced through the second passage. The projecting portion of the on-off valve projecting into the second passage does not particularly hinder the intake.

Further, by forming the second passage in a curved upper and lower two-stage configuration, the length of the second passage can be sufficiently ensured.

<< Example >> Hereinafter, an example of the present invention is described with reference to drawings.

In this embodiment, the present invention is applied to a vertical V-type six-cylinder engine. FIG. 1 is a front view of the V-type six-cylinder engine, and FIG. 2 is a plan view thereof.

In the intake system for an engine according to the present invention, a first passage (high-speed intake passage 10) having a short path length through which intake air to be introduced into each cylinder during high-speed operation is introduced through an intake passage of a multi-cylinder engine.
And a second passage (the communication passage 11 and the low-speed intake passage 12) having a long path length through which the intake air introduced into each cylinder flows at the time of low-speed operation. The first passage portion is provided with an on-off valve 14 for opening the first passage in a high-speed rotation region and closing the low-speed rotation region in the first passage portion. The valve 14 is basically arranged such that the side surface facing the second passage side when the first passage is closed is arranged along the streamline direction of the second passage when the valve 14 is close to the integrated portion with the second passage. Configuration.

More specifically, the engine body 1 has three cylinders 4 in each of the banks 2 and 3 facing left and right in a V-shape.
An intake port 7 of each cylinder is formed in each of the cylinder heads 5, 6 on the opposing surface side of each of the banks 2, 3. Above the right bank 5 of the engine body 1, a long first surge tank 8 is provided along the cylinder arrangement direction, and above the left bank 3, the cylinders are arranged to face the first surge tank 8. An elongated second surge tank 9 along the arrangement direction is provided.

The first surge tank 8 is connected to the throttle body 15 and is mainly used for a high-speed operation range. That is, the first surge tank 8 is communicated with the intake port 7 of each cylinder 4 via a high-speed intake passage 10 having a short path length as a first passage. The first surge tank 8 is connected to the left and right banks 2,
The first surge tank 9 is communicated with the second surge tank 9 by a single communication passage 11 formed across the space between the three and forming a part of the second passage. The pipes forming the communication passage 11 are provided on the rear sides of the surge tanks 8 and 9 so as to be offset.

On the other hand, the second surge tank 9 is mainly used for a medium-to-low speed operation range, and is provided in each of the intake ports 7 of the six cylinders 4 with a curved low-speed intake passage 12 having a long path length and forming a part of the second passage. Are communicated through. Further, the low-speed intake passage 12 is connected to the second surge tank 9 at a lower position below the communication passage 11, and the second passage is arranged in a two-stage configuration in a vertical direction as a whole. In addition, the second passage is formed into a curved upper and lower two-stage configuration, so that the passage length can be sufficiently ensured.

The tip of the high-speed intake passage 10 is connected to the low-speed intake passage 12.
The high-speed intake passage 10 and the low-speed intake passage 12 are connected in parallel to each other at the center between the banks 2 and 3. In addition, a branch pipe 13 having a bifurcated appearance is provided in the integrated portion, and communicates with each intake port 7. That is, as shown by the broken lines in FIG. 1, the branch pipe 13 has two independent passages respectively communicating with the two intake ports 7 formed to be shifted to the left and right banks 2 and 3 in the front and rear directions. In this case, the flange portion on the upper end portion side is made common and integrally formed to achieve compactness and space saving.

The high-speed intake passage 10 is provided with an on-off valve 14 that opens the high-speed intake passage 10 in a high-speed rotation range of the engine and closes the low-speed intake passage in a low-speed rotation range. It is located in the integrated portion of 10, 10 and is arranged as close as possible to the low-speed intake passage 12 side. Further, when the high-speed intake passage 10 is closed, the on-off valve 14 has a valve body surface 14 on the side facing the low-speed intake passage 12.
a is along the streamline direction of the low-speed intake passage 12, and when the high-speed intake passage 10 is opened, the valve opening angle is
It is set to follow the flow direction of the intake air from the side.

Accordingly, in the engine intake device constructed in this manner, in the low-speed operation range of the engine, the high-speed intake passage 10 as the first passage is closed by the on-off valve 14, so that the intake air flows from the throttle body 15 to the first surge tank 8 , Connecting passage
11, the second surge tank 9 and the low-speed air supply passage 12 having a long path length sequentially flow down, and the banks 2, 3 are passed through the second passage.
Is introduced into each of the cylinders 4.

At this time, the low-speed intake passage 12 and the high-speed intake passage 10
An opening / closing valve 14 provided in an integrated portion of the low-speed intake passage 12 has a valve body surface 14 a facing the low-speed intake passage 12.
The low-speed intake passage is arranged as close as possible to the low-speed intake passage 12 along the streamline direction of the low-speed intake passage 12.
The flow path cross-sectional area of the twelve does not drastically change in the integrated part, and turbulence generated in the part is suppressed as much as possible. Therefore, the flow of the intake air in the low-speed motion region of the engine, in which the intake air is introduced through the low-speed intake passage (second passage) 12, is made as smooth as possible, and the intake efficiency can be further improved. As a result, it is possible to prevent the occurrence of torque fluctuation due to the disturbance of the motor as much as possible.

Also, in the high-speed operation range, the on-off valve 14 of the high-speed intake passage 10 is opened, and almost half of the on-off valve 14 projects into the low-speed intake passage 12. Most of the gas is introduced into each cylinder through a high-speed intake passage (first passage) 10 having a short path length and a part of the gas is introduced through a low-speed intake passage 12, so that particularly large turbulent flow is generated in the integrated portion. In addition to preventing the intake air from being generated, the intake air is not obstructed, but also promotes the intake air through the high-speed intake passage 10, so that the intake efficiency can be further improved.

The first surge tank 8 is located closer to the center between the banks than the second surge tank 9 is. This allows
The length of the high-speed intake passage 8 is set as short as possible, and a space is formed above the right bank 4.
A throttle body 15 is provided in a space above the right bank 4, and the throttle body 15 is connected to the outside of the first surge tank 8. 15a is a pipe to an air cleaner detachably connected to the throttle body 15, and 15b is an idle speed controller.

Here, the one first surge tank 8 is arranged near the center between the banks, and the throttle body 15 is connected to the first surge tank 8 and arranged in a space formed above the right bank 2 on the outside thereof. As a result, the length of the air supply pipe system including the throttle body 15 and the air cleaner on the upstream side of the first surge tank 8 can be made as short as possible to form a compact intake system. The pipe system can be easily managed, and the appearance in the engine room and the ease of assembly and maintenance can be improved.

Also, since the length of the intake pipe system on the upstream side of the first surge tank 8 can be made as short as possible, the length of the high-speed intake passage 8 itself is set as short as possible. For example, the airflow resistance in a high-speed operation region in which intake air is introduced from the high-speed air supply passage 8 is reduced.
The intake efficiency in the high-speed operation range can be improved as much as possible.

The first surge tank 8 has a shape whose cross-sectional area gradually expands toward the downstream side from the intake port on the throttle body 15 side along the streamline of intake air. Thereby, the intake distribution at the time of high-speed operation is improved.

Further, a pipe constituting a communication path 11 between the first surge tank 8 and the second surge tank 9 is provided to be offset to the rear side of both surge tanks 8 and 9. Thereby, since the communication passage 11 having the highest height in the intake system is arranged on the rear side, the hood line of the vehicle which is normally inclined forward (the virtual line in FIG. 2 and FIG. 3). The height relationship is the same as that of the line a), so that the requirement for lowering the hood line is met.

<< Effects of the Invention >> As described in detail above, according to the engine intake device of the present invention, when the first passage (high-speed intake passage) is closed by the on-off valve in the low-speed operation range of the engine, In this on-off valve, the valve body surface facing the second passage (low-speed intake passage) is in a state of being close to the second passage and along the streamline direction, so that the flow passage cross-sectional area of the second passage Does not significantly change at the integrated portion with the first passage, and the occurrence of turbulence is suppressed as much as possible. Therefore, in the low-speed engine operation region in which intake is performed through the second passage, smooth intake can be achieved and the intake efficiency can be further improved, so that torque fluctuation can be prevented as much as possible. This is an excellent effect.

Further, by forming the second passage in a curved upper and lower two-stage configuration, the length of the second passage can be sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of an intake device for an engine according to the present invention, and FIG. 2 is a plan view thereof. DESCRIPTION OF SYMBOLS 1 ... Engine body, 4 ... Cylinder 7 ... Intake port, 10 ... High-speed supply passage (first passage) 11 ... Communication passage (second passage), 12 ... Low-speed intake passage (second passage) Passage) 14 ... On-off valve

────────────────────────────────────────────────── (5) References JP-A-63-266158 (JP, A) JP-A-61-255215 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02B 27/02 F02M 35/116

Claims (1)

(57) [Claims] An intake passage of a multi-cylinder engine is provided with a first passage having a short path length through which intake air to be introduced into each cylinder during high-speed operation is introduced.
The first passage and the second passage are branched into a passage and a curved second passage having a long path length through which intake air introduced into each cylinder flows during low-speed operation, and the first passage and the second passage are integrated and arranged in front of each cylinder. An on-off valve for opening the first passage in a high-speed rotation region of the engine and closing the first passage in a low-speed rotation region, and the on-off valve is integrated with the second passage in the first passage portion. , The side surface facing the second passage side when the first passage is closed is arranged along the streamline direction of the second passage, and the second passage has an upper and lower two-stage configuration. Characteristic engine intake device.