JPH029090Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an improvement in an engine intake system.

(Prior art) For example, in a V-type engine, the interior of the surge tank disposed approximately in the center of the two left and right banks is divided into two chambers by a partition wall, and the first chamber of the surge tank and the intake air of the cylinders of one bank are divided into two chambers by a partition wall. A first intake pipe that connects the port and a second intake pipe that connects the second chamber of the surge tank and the intake port of the cylinder of the other bank are crossed below the surge tank between both banks. The present applicant has proposed an intake device in which the air intake device is installed in the air (see Japanese Patent Application No. 59-65624).

This intake device prevents intake air interference at the gathering portion of the intake pipes connected to each cylinder, and also prevents the supercharging effect (hereinafter referred to as resonance supercharging effect) caused by pressure vibrations due to the influence of the intake pipes on the upstream side of the surge tank. )
It was designed to use the .

By the way, the liquid contained in blow-by gas, water, gasoline, EGR gas, etc. may liquefy and accumulate at the bottom of the surge tank, and this liquid is led all at once from the surge tank to the combustion chamber through the passage. This may cause the engine to misfire.

In order to prevent this, a structure can be considered that sequentially drains the accumulated liquefaction. For example, if the surge tank is divided into two chambers as described above, each chamber and the intake passage are connected through a liquid drainage passage. Thus, the liquid content in each chamber can be discharged from each liquid drain passage to the intake passage, and can be configured to be guided from the intake passage to the combustion chamber.

However, since it is necessary to seal two places at the mating surfaces of each liquid drain passage on the surge tank side that communicates with each chamber and each liquid drain passage on the intake manifold side that communicates with the intake passage, the seal structure becomes complicated. There was a problem.

(Purpose of the invention) The present invention was made to solve the above problem, and the purpose of this invention is to simplify the sealing structure by adding innovation to the configuration of the liquid drain passage that communicates each chamber of the surge tank with the intake passage. The purpose is to

(Structure of the invention) For this reason, the present invention provides an intake system for an engine including a surge tank into which intake air is introduced, including a partition wall that divides the inside of the surge tank into two chambers, a first chamber and a second chamber, An intake pipe connecting the first chamber of the surge tank and the intake port of the cylinder is provided, and the intake pipe faces the bottom wall of the surge tank below the surge tank, and has one end connected to the first chamber,
This is characterized by the provision of passages that open in the bottom wall of the second chamber, converge midway on the surge tank side, and open at the other end to the intake pipe.

(Effect of the invention) According to the invention, the first and second chambers of the surge tank
Two passages that communicate with the chambers are combined into one passage midway on the surge tank side, and this one passage is communicated with one passage on the intake pipe side, so the surge tank side Since it is only necessary to seal at one location on the mating surface of the passageway and the passageway on the intake pipe side, the sealing structure becomes simple.

Further, since the passages in each chamber are simply assembled into one passage, the passage structure is simple and liquid can be drained reliably.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a six-cylinder V-type engine 1 has a first cylinder head 3a and a second cylinder head 3b arranged on a cylinder block 2 at an angle. A first bank 1A and a second bank 1B each having cylinders 4a and 4b are formed.

First and second banks 1A and 1B on both sides of the above
An intake passage 5 that supplies intake air to each cylinder 4a, 4b.
is equipped with a surge tank 6 disposed in the upper part between banks 1A and 1B on both sides.

This surge tank 6 and the first and second banks 1
The first and second intake pipes 8A and 8B that connect the intake ports 7a and 7b of the banks A and 1B are connected on the downstream side to the intake port 7a of the first bank 1A on the left side under the surge tank 6. The intersection 9a of the downstream part of the first intake pipe 8A that has been connected to the first intake pipe 8A and the intersection 9b of the downstream part of the second intake pipe 8B whose downstream side is connected to the intake port 7b of the second bank 1B on the right side. They intersect with each other, and the upstream sides of the intersections 9a and 9b are bent into a U-shape, and the U of the first intake pipe 8A
The upstream end of the U-shaped portion 10a is connected to the right side of the surge tank 6, and the upstream end of the U-shaped portion 10b of the second intake pipe 8B is connected to the left side of the surge tank 6.

The internal space of the surge tank 6 is divided into a first chamber 6a that is separated from left to right by a partition wall 11 that extends in the front-rear direction (parallel to the output shaft direction of the engine).
and a second chamber 6b.

A first intake pipe 8A connected to the first bank 1A on the left side communicates with the first chamber 6a on the right side through a communication port 6c opened on the right side surface, and the second chamber 6b on the left side communicates with the first intake pipe 8A connected to the first bank 1A on the left side through a communication port 6c opened on the right side surface. A second intake pipe 8B connected to the second bank 1B on the right side communicates through a communication port 6d opened at the rear end of the surge tank 6 in the longitudinal direction. As shown in , the intake pipe 12 on the inflow side is connected from the engine output shaft direction,
A partition wall extension 12c that is continuous with the partition wall 11 is also provided in the intake pipe 12 on the inflow side, and an independent passage 12a that communicates with the first and second chambers 6a and 6b of the surge tank 6 and supplies intake air. It is divided into 12b. A throttle valve (not shown) is provided in each of the independent passages 12a, 12b, and these throttle valves are operated synchronously to open and close at the same angle.

Furthermore, the length of the partition wall extension 12c, that is, the length from the surge tank 6 to the confluence section, is determined by the pressure vibrations generated by the influence of the intake pipe 12 upstream of the surge tank 6 at a desired engine speed. is arbitrarily set so that the resonance supercharging effect due to the phenomenon that affects the intake process of each cylinder 4a, 4b reaches its peak and an output improvement is obtained.

At each intersection 9a, 9b of the intake pipes 8A, 8B downstream of the surge tank 6, fuel injection nozzles 14, 14 are arranged to inject fuel into the intake ports 7a, 7b of each cylinder 4a, 4b. There is. Additionally, in FIG. 1, 15 is an intake valve, and 16 is a piston.

On the other hand, as shown in detail in FIG. 3, on the bottom wall of the surge tank 6, a lower protrusion 20 is formed that protrudes downward from directly below the partition wall 11, and a lower protrusion 20 is formed in the middle of the intake pipe 8A. A protrusion 21 is formed that protrudes upward from the intake pipe 8A,
The lower surface of the lower protrusion 20 and the upper surface of the upper protrusion 21 are mating surfaces.

The bottom wall of each chamber 6a, 6b of the surge tank 6 has two passages 23 inclined toward the lower protrusion 20.
a, 23b are formed, and each passage 23
a and 23b are gathered into one passage in the middle of the lower protrusion 20, and this one passage 23b opens at the lower surface of the lower protrusion 20.

Further, one passage 24a is formed in the upper protrusion 21 of the intake pipe 8A, and the passage 24a opens on the upper surface of the upper protrusion 21 so as to face the passage 23b.

The passage 23b of the lower protrusion 20 and the upper part of the passage 24a of the upper protrusion 21 are formed to have a large diameter, and a tubular pin 25 for positioning is fitted across the large diameter portion of each passage 23b, 24a. A seal ring (O-ring) 26 is provided on the upper surface of the upper protrusion 21 to seal between the tubular pin 25 and the lower surface of the lower protrusion 20 .

If the configuration is as above, bank 1 on both sides
Intake air is supplied to each cylinder 4a, 4b of A, 1B through a throttle valve, and each passage 12a, 4b of the intake pipe 12.
12b to each chamber 6a, 6b of the surge tank 6.
The intake air flowing into the surge tank 6 from the communication ports 6c and 6d on the sides of the surge tank 6 flows into the intake pipes 8A and 8B on both sides, respectively.
flows into the U-shaped portions 10a and 10b, and this U-shaped portion 10
a, 10b to the lower side of the surge tank 6, and then intersect with each other at intersections 9a, 9b to flow into each cylinder head 3a, 3, respectively.
Each cylinder 4a, 4b from the intake port 7a, 7b of
will be supplied to

The liquid accumulated in each chamber 6a, 6b of the surge tank 6 is removed from the passages 23a, 23 of the lower protrusion 20.
After the liquid is drained through the passage 23b and collected in the passage 23b, it is discharged into the intake pipe 8A through the passage 24a of the upper protrusion 21, and is led from the intake pipe 8A to the combustion chamber.

Therefore, two of each chamber 6a, 6b of the surge tank 6
The main passages 23a, 23a are gathered into one passage 23b, and this passage 23b is connected to one passage 24a on the side of the intake pipe 8A.
Only one 6 is required, which simplifies the seal structure.

Furthermore, the tube pin 25 prevents negative pressure within the intake passage from acting on the seal ring 26, thereby maintaining sealing performance.

Note that the passages 23a, 23a, 23b, and 24a communicate cylinder groups with different phases, so there is a risk that the resonance supercharging effect will be reduced.
If the total length of a and 23a is l, the passage diameter is d, the total length of independent passages 12a and 12b is L, and the passage diameter is D, then if the requirement of l>L/α ² (α=D/d) is satisfied. ,
It is possible to prevent the resonance supercharging effect from decreasing.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a V-type engine according to the present invention,
2 is a plan view of FIG. 1, FIG. 3 is an enlarged view of the main part of FIG. 1, and FIG. 4 is a schematic plan view showing the relationship between the surge tank and the intake pipe. 1...V-type engine, 1A, 1B...bank,
4a, 4b...Cylinder, 6...Surge tank, 8
A, 8B, 12...Intake pipe, 11...Partition wall, 2
0...Lower protrusion, 21...Upper protrusion, 23a, 2
3b, 24a... passage, 25... tubular pin, 26... seal ring.

Claims (1)

[Claims for Utility Model Registration] In an engine intake system equipped with a surge tank into which intake air is introduced, a partition wall is provided to divide the interior of the surge tank into two chambers, a first chamber and a second chamber, and the surge tank An intake pipe connecting the first chamber and the intake port of the cylinder is provided, and the intake pipe is located below the surge tank and faces the bottom wall of the surge tank, with one end at the bottom of the first chamber and the bottom of the second chamber. An intake system for an engine, characterized in that passages are provided, each opening in a wall, then converging midway on the surge tank side, and opening at the other end into an intake pipe.