JPH0216004Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a blow-by gas treatment device for an engine in which a surge tank and each cylinder in the engine body are connected via an intake manifold.

(Prior art) Some engines have a surge tank and each cylinder of the engine connected via an intake manifold, and in order to obtain dynamic effects of intake air, especially inertial supercharging, an intake passage is constructed within a limited engine room space. In order to make the length as long as possible, it has been proposed that an independent intake passage connected to each cylinder from the surge tank be arranged so as to surround the surge tank.
58-20333).

By the way, blow-by gas from the engine body can be returned to the intake passage, that is, to each cylinder.
Conventionally, this blow-by gas was introduced into a surge tank and distributed from the surge tank to each cylinder via each independent intake passage.

(Problem to be solved by the invention) However, when the blow-by gas is returned to the surge tank as in the above-mentioned conventional method, the liquefied blow-by gas tends to remain on the bottom wall of the surge tank, which causes corrosion of the surge tank. This tends to cause problems such as a large amount of liquefied blow-by gas being suddenly supplied to each cylinder during engine transients or the like.

In addition, blow-by gas is easily cooled, that is, it tends to cause icing, and some kind of measure is desired to prevent this icing.

Therefore, the purpose of the present invention is to prevent blow-by gas from accumulating in the middle of the intake passage, and
An object of the present invention is to provide a blow-by gas treatment device for an engine which can also prevent icing.

(Means and actions for solving the problem) In order to achieve the above-mentioned object, the present invention provides blow-by gas to a surge tank whose bottom wall has a large area and where blow-by gas tends to accumulate. Focusing on the fact that the engine body side part of the intake manifold that connects this surge tank and each cylinder in the engine body is easily heated, the intake manifold near the engine body is Blow-by gas is refluxed from the section. Specifically, in an engine in which a surge tank and each cylinder of the engine body are connected via an intake manifold, the surge tank is located above the intake manifold, and each independent intake passage in the intake manifold is connected to the surge tank. and a bottom wall surface of the surge tank, a thick part is provided in the vicinity of the engine body, a blow-by gas distribution hole extending in the cylinder arrangement direction is formed in the thick part, and a blow-by gas distribution hole is formed in each of the independent intake passages. In contrast, a branch port extending downward from the distribution hole is opened, and a common introduction port for introducing blowby gas from the engine main body is opened to the distribution hole. It is configured as a processing device.

With this configuration, not only does blow-by gas not accumulate in the surge tank at all, but the distribution hole in the thick part is as close to the engine body as possible, so this distribution hole can be easily removed from the engine body. The blow-by gas passage leading up to this can be absolutely shortened, and icing and blow-by gas retention in this period can also be prevented.
In addition, the above-mentioned thick portion easily receives heat from the engine body and is sufficiently warmed, while the thick portion around the distribution hole prevents the heat retained in the blow-by gas from radiating to the outside as much as possible. It turns out. For this reason,
This also prevents icing.

Moreover, since the above-mentioned thick part is provided between each independent intake passage and the bottom wall surface of the surge tank, blow-by gas is transferred to the upstream side of the engine body (of course, from the surge tank) to each independent intake passage. Compared to the case where blow-by gas is introduced into the intake passage by forming a distribution hole in the thick part of the engine body, it is possible to introduce blow-by gas from the introduction point to the intake valve. This means that the distance can be increased. Therefore, by ensuring this distance, blow-by gas can be mixed appropriately.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIG. 1, reference numeral 1 denotes an engine body, which in this embodiment has a main combustion chamber 5 defined by a cylinder block 2, a cylinder head 3, and a piston 4 fitted into the cylinder block 2. This is a sub-chamber type four-cylinder diesel engine which has a sub-chamber 7 in the cylinder head 2 which communicates with a main combustion chamber 5 through a nozzle 6. In the main combustion chamber 5,
An intake port 9, which is opened and closed at a known timing by an intake valve 8, is opened, and an intake passage member A, which will be described later, is opened.
Intake air is supplied to the intake port 9 through the intake port 9.

The above-mentioned intake passage member A is divided into two parts, and the surge tank A1 located on the upper side and the intake manifold A2 located on the lower side are fixed via an elastic member 10. Member A connects intake manifold A2 with bolts 11.
By fixing it to the engine body 1 (cylinder head 3) by means of the above, it is fixed and held to the engine body 1.

As shown in FIGS. 2 and 3, the surge tank A1 is arranged in the cylinder arrangement direction (direction perpendicular to the plane of the paper in FIG. 1).
The tank part 13 extends long to define the intake expansion chamber 12 inside, and this tank part 13 (intake expansion chamber 1
2) It has upstream side independent intake pipe portions 15A forming upstream side independent intake passages 14A that extend individually and independently. In addition, the intake manifold A2 constitutes a downstream independent intake pipe section 15B which has therein a downstream independent intake passage 14B that is connected to the upstream independent intake passage 14A, and as will be described later, when coupled to the surge tank A1. , which constitutes the tank portion 13, that is, the bottom wall of the intake expansion chamber 12.

The upstream and downstream independent intake passages 14A,
Independent intake passage 14 consisting of 14B (both intake pipe parts 1
In the embodiment, the independent intake pipe portion 15) consisting of 5A and 15B is configured to be as long as possible, so the upstream independent intake passage 14A is formed in a substantially semicircular arc shape with the axis extending in the cylinder arrangement direction as the center. has been done.
That is, the upstream independent intake passage 14A is led out from the side surface of the engine body 1 of the tank portion 13 and once rises upward, and then runs along the upper wall of the surge tank portion 13, and then extends from the side of the engine body 1 of the tank portion 13. It extends downward along the opposite side wall and is finally opened downward. A downstream independent intake passage 14B is connected to the upstream independent intake passage 14A that is open downward, and extends to the intake port 9 through the lower part of the tank portion 13.
Note that the elastic member 10 has the above-mentioned independent intake passage 14.
Notch 10a or communication port 1 connected to A, 14B
0b is formed (see Figure 5).

The independent intake pipe section 15 itself that constitutes the above-mentioned independent intake passage 14 therein, on the surge tank A1 side, that is, on the upstream independent intake pipe section 15A side, is connected to the engine body 1 side and the opposite side of the tank section 13, as well as the upper wall surface. This wall is also used as one wall of the intake pipe 15 (this wall that also serves as a wall is shown as a partition wall 16). Further, the upper wall surface of the intake manifold A2 is connected to the tank portion 13.
It constitutes the bottom wall surface of the (intake expansion chamber 12), and
It is configured as an integrally molded branch pipe having an independent intake passage 14 inside, and there is a wall between the bottom wall surface and each independent intake passage 14 in the vicinity of the engine body 1, as shown in FIG. A thick portion P is provided. In this way, surge tank A1
is the intake expansion chamber 12 and the upstream independent intake passage 1
While both parts of 4A are greatly released downward,
The intake manifold A2 has a large open upper surface corresponding to the intake expansion chamber 12 and the upstream independent intake passage 14A (see FIG. 4).

In this way, since the intake passage member A is divided into the surge tank A1 or the intake manifold A2 which is largely opened upward or downward, the entire periphery is closed inside both A1 and A2. There are no closed spaces, and manufacturing (generally casting) is easy. The surge tank A1, which constitutes most of the surface area of the tank portion 13 excluding only the bottom wall portion, is located at the engine main body 1.
On the other hand, vibrations of the engine body 1 are effectively prevented from being transmitted to the surge tank A1, particularly the tank portion 13, through the elastic member 10 having a sufficient wall thickness (elasticity).

Here, the surge tank A is inserted through the elastic member 10.
FIG. 6 shows an enlarged view of the joining area between the intake manifold A2 and the intake manifold A2. That is, as shown in FIG. 4, a plurality of screw holes 17 (12 in the embodiment) are formed in the fixing flange of the intake manifold A2, and bolts passing through the fixing flange of the surge tank A1 are formed. 18 into the screw hole 17, the surge tank A1 and the intake manifold A2 are fixed.

In addition, 19 and 20 in FIG. 6 are sleeves,
The sleeve 19 is located on the outer peripheral surface of the bolt 18 and is located in the positioning hole 2 formed in the elastic member 10.
1 to prevent displacement of the elastic member 10, and similarly, the sleeve 20 is
It is designed to be fitted into the positioning hole 22 of the surge tank A1 for positioning. Also, the 6th
31 in the figure is a washer.

Next, the blowby gas recirculation passage will be explained. This blowby gas is supplied to the intake passages 14 and 14B in the intake manifold A2. To explain this point in detail, the thick part P of the intake manifold A2 has an engine main body 1.
A distribution hole 23 extending in the cylinder arrangement direction is formed by drilling, for example, in the vicinity of the cylinder arrangement direction (see Fig. 4), and a branch port 24 leading from the upper end surface of the intake manifold A2 through this distribution hole 23 to the intake passage 14 is formed.
However, the number of holes corresponding to the number of cylinders is formed by drilling. The opening toward the upper end surface of the intake manifold A2 due to the formation of the branch port 24 is closed by the elastic member 10.
On the other hand, in locations where the elastic member 10 is not located,
In the intake manifold A2, one common inlet 25 extending from the upper end surface to the distribution hole 23 is formed by drilling, and an L-shaped connecting pipe is connected to the pipe 26 fitted to the inlet 25. A blow-by gas outlet 29 extending from the cylinder head cover 28 is connected through the cylinder head cover 27 .

As a result, the blow-by gas inside the cylinder head cover 29 is transferred to the connecting pipe 27 and the common inlet 2.
5 to the distribution hole 23, and this distribution hole 2
3 and is distributed and supplied to each independent intake passage 14 from each branch port 24. In this case, since the intake manifold A2 itself is fixed to the engine body 1 only via a normal gasket 30, it receives enough heat from the engine body 1 to warm up, thereby preventing blow-by. Gas icing is effectively prevented. Moreover, since the distribution hole 23 is formed in the thick wall portion P, the thickness of the peripheral edge of the distribution hole 23 can be increased, and the heat retained in the blow-by gas in the distribution hole 23 is radiated to the outside. This can be prevented as much as possible.
Therefore, also from this point of view, it is possible to prevent icing. In addition, in the blow-by gas passage, a bottom wall with a large area (especially a recessed bottom wall) where stagnation occurs in the middle
Since there is no special formation of water, it is always smoothly distributed and supplied to each cylinder. Furthermore, since the distribution hole 23 and each branch port 24 are formed in the thick portion P, each branch port 24 is connected to each independent intake passage 14.
On the other hand, the opening can be made upstream of the engine body and downstream of the surge tank A1, and mixing of blowby gas and intake air can be achieved while avoiding retention of blowby gas in the surge tank A1. Therefore, the branch port 24
This means that the distance from the intake valve 8 to the intake valve 8 can be appropriately set.

FIG. 8 shows a second embodiment of the present invention, in which the same components as in the previous embodiment are given the same reference numerals and their explanations are omitted (this also applies to other embodiments below). ) In this embodiment, the distribution hole 23 for blow-by gas distribution formed in the intake manifold A2 is configured in the form of a "groove" that opens at the upper end surface of the intake manifold A2, that is, the dividing surface with respect to the surge tank A1. The upper opening of the groove-shaped distribution hole 23 is hermetically closed by the elastic member 10.

FIG. 9 shows a third embodiment of the present invention, in which the blow-by gas distribution hole 23 is of the groove type similar to that shown in FIG.
3 and each independent intake passage 14 are communicated through a pipe 24' forming a branch port 24.
By using such a pipe 24', it becomes possible to reduce the thickness below the distribution hole 23, which is advantageous in making the intake manifold A2 as light as possible. Furthermore, in this embodiment, the common introduction port 25
is formed within the wall of the surge tank A1.

Although the embodiment has been described above, in order to make the distribution from the distribution hole 23 to each branch port 24 as good as possible, the bottom wall of the distribution hole 23 is gradually lowered as it moves away from the common inlet 25. You may do so. In this case, if the distribution hole 23 is formed by drilling as shown in FIGS. 1 and 7,
It is sufficient to machine the intake manifold A2 by cutting it so as to gradually increase its height from each end in the cylinder arrangement direction toward the common introduction port 25.

(Effects of the invention) As described above, the present invention can prevent blow-by gas from accumulating in the middle of the intake passage, and
Icing can also be effectively prevented, and blow-by gas can be mixed appropriately in the intake system.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a sectional view taken along the line shown in FIG. 2. FIG. 2 is a top view of the intake passage member (surge tank). FIG. 3 is a side view of the intake passage members (surge tank and intake manifold) seen from the side where they are attached to the engine body. FIG. 4 is a top view of the intake manifold. FIG. 5 is a top view of the elastic member. FIG. 6 is an enlarged sectional view showing a joint portion between a surge tank, an intake manifold, and an elastic member. FIG. 7 is an enlarged sectional view showing the blow-by gas introduction part. FIGS. 8 and 9 each show another embodiment of the present invention, and are enlarged sectional views of portions corresponding to FIG. 7. A: Intake passage member, A1: Surge tank, A
2: intake manifold, 1: engine body, 9: intake port, 10: elastic member, 12: intake expansion chamber,
13: Tank part, 14: Independent intake passage, 14A:
Upstream independent intake passage, 14B: Downstream independent intake passage, 15: Independent intake pipe, 15A: Upstream independent intake pipe section, 15B: Downstream independent intake pipe section, 23: Distribution hole, 24: Branch port, 25: 27: Connection pipe, 29: Blow-by gas outlet.

Claims (1)

[Claims for Utility Model Registration] In an engine in which a surge tank and each cylinder of the engine body are connected via an intake manifold, the surge tank is located above the intake manifold, and each cylinder in the intake manifold A thick wall portion is provided near the engine body between the independent intake passage and the bottom wall surface of the surge tank, a blow-by gas distribution hole extending in the cylinder arrangement direction is formed in the thick wall portion, and each independent An engine characterized in that a branch port extending downward from the distribution hole is opened to the intake passage, and a common inlet port for introducing blow-by gas from the engine body is opened to the distribution hole. blow-by gas treatment equipment.