JP3668445B2 - Multi-cylinder engine intake system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for a multi-cylinder engine, and more particularly to an intake device in which an EGR gas distribution passage and a blow-by gas distribution passage are integrally formed on an upper surface of an intake manifold.
[0002]
[Prior art]
Reducing the blow-by gas in the crankcase to the intake passage to relieve pressure pulsation in the crankcase and prevent deterioration of the lubricating oil in a closed loop, or reduce NOx by reducing the combustion temperature Therefore, an EGR device is known in which a part of the inert exhaust gas is recirculated to the intake passage.
[0003]
Japanese Utility Model Publication No. 4-15977 includes a plurality of intake pipes arranged in parallel to each other as a method for relatively easily forming a blow-by gas distribution passage for distributing the blow-by gas to each cylinder. between the intake pipes to each other to form integrally a seat across the direction of the row of cylinders to the upper surface of the intake manifold, and recessed a plurality of grooves in parallel to the base, and the opening surface of the groove is covered with a flat plate-like cover A structure relating to a negative pressure sampling port is disclosed. According to this prior art, any one of the plurality of grooves can function as a reflux path for blow-by gas.
[0004]
[Problems to be solved by the invention]
However, as in the structure disclosed in the above publication, when blow-by gas is introduced to the intake upstream side of a negative pressure sampling port such as a throttle bypass passage, the oil mist in the blow-by gas is connected to the other cylinder connected to the other negative pressure sampling port. It is inevitable to enter the aisle. Similarly, when the EGR gas is recirculated to the intake passage in order to reduce the NOx by reducing the combustion temperature, the introduction of the blow-by gas to the intake upstream side is aimed at the discharge port of the EGR gas to the intake passage. This is not preferable because it causes clogging.
[0005]
The present invention has been devised to solve such problems of the prior art, and its main purpose is to prevent carbon from adhering around the EGR gas outlet opening in the intake passage. It is another object of the present invention to provide an improved intake device for a multi-cylinder engine.
[0006]
[Means for Solving the Problems]
To achieve the above objects, the present onset Ming, the top surfaces of the plurality of branch pipes connected to intake ports of each cylinder (2 a to 2 d), extending in the cylinder row direction across the inter-branch adjacent to each other And two pedestals (11, 12) having grooves (14, 15) each having an open top surface, and two grooves (25, 26) corresponding to the grooves are formed on the inner surface. a lid member (27) forms the shape of the blow-by gas distribution passage (29) individually independent EGR gas distribution passage (30) by sticking to the upper surface of the pedestal was, to each branch tube of the EGR gas distribution passage The discharge passage holes (24a to 24d) are arranged on the upstream side of the intake passages (22a to 22d) into the branch pipes of the blow-by gas distribution passage, and the upper surface of the branch pipe, the pedestal, and the lid Parts and An air intake device for a multi-cylinder engine is provided, which is provided with a gap (13) for forming an air layer between them.
[0007]
Thus, if blow-by gas is discharged to the intake downstream side of the EGR gas discharge port, carbon can be prevented from adhering around the EGR gas discharge port. It can be maintained for a long time. In addition, since an air layer is formed between the EGR gas distribution passage and the blow-by gas distribution passage, the heat of the relatively high temperature EGR gas transmitted to the blow-by gas is mitigated through the air layer. Even if the EGR gas passage and the blow-by gas passage are provided in parallel, the oil mist in the blow-by gas can be prevented from carbonizing and the passage can be prevented from being clogged.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0009]
FIG. 1 shows an entire intake system to which the present invention is applied. This intake system is provided on a surface facing forward when mounted on the engine body (not shown), and an intake manifold 2 connected to an intake port (not shown) provided in the cylinder head, An intake chamber 3 with a resonator connected to the intake upstream end of the manifold 2, a throttle body 4 connected to an intake inlet opening at the upper surface of the right end of the intake chamber 3, and an end of the intake manifold 2 on the side opposite to the throttle body And an EGR valve 6 for controlling the exhaust gas recirculation amount.
[0010]
The intake manifold 2 is formed, for example, by casting an aluminum alloy. As shown in FIG. 2, the intake manifold 2 has four elbow-shaped curves so as to connect the upper surface of the intake chamber 3 and the front surface of the cylinder head. It consists of branch pipes 2a to 2d.
[0011]
On the upper surface of the four branch pipes 2a to 2d, two pedestals 11 and 12 extending in the cylinder row direction across the adjacent branch pipes are provided in the front-rear direction with a gap 13 therebetween. They are formed in parallel. These two bases 11 and 12 are formed with grooves 14 and 15 having open upper surfaces, respectively.
[0012]
A mounting seat 16 for the EGR valve 6 is formed at a position adjacent to the left ends of the bases 11 and 12. On the upper surface of the EGR valve mounting seat 16, there are an EGR inlet passage 17 for introducing a part of exhaust gas into an EGR valve 6 from an exhaust port (not shown) through the cylinder head, and an intake manifold joint surface 1 a of the cylinder head 1. EGR outlet passages 19 connected to the recessed grooves 18 (see FIGS. 4 and 6) are opened.
[0013]
A groove 18 formed in the intake manifold joint surface 1a of the cylinder head 1 extends between the second cylinder and the third cylinder as shown in FIGS. 4 and 6, and the intake manifold It connects with the inlet 20a of the connection path 20 provided in the center part of 2 cylinder row direction.
[0014]
As shown in FIGS. 2 and 5, the branch pipes 2 a to 2 d are provided between the groove 14 recessed in the base 11 near the cylinder head 1 and the cylinder head joint surface 21 of the intake manifold 2. Blow-by gas discharge passage holes 22a to 22d are formed. These blow-by gas discharge passage holes 22 a to 22 d communicate with each intake port through a recess 23 formed in the intake manifold joint surface 1 a of the cylinder head 1.
[0015]
As shown in FIGS. 2, 5, and 6, EGR gas discharge penetrating inside the branch pipes 2a to 2d is provided at the bottom of the groove 15 recessed in the base 12 far from the cylinder head 1. Passage holes 24a to 24d are formed.
[0016]
A lid member 27 formed on the inner surface with two grooves 25 and 26 corresponding to the grooves 14 and 15 formed on the pedestals 11 and 12 is sandwiched between the two pedestals 11 with a common gasket 28 interposed therebetween. By adhering to the upper surface of 12, as shown in FIGS. 4 and 5, there are two passages 29 and 30 that extend in the cylinder row direction independently with a gap 13 therebetween. It is formed.
[0017]
A hose port 31 for communicating with the inside of the blow-by gas distribution passage 29 is fixed to the lid member 27 and communicates with the inside of the crankcase via a hose (not shown) connected thereto. The blowby gas is introduced into the blowby gas distribution passage 29.
[0018]
According to this, the EGR gas that has passed through the EGR valve 6 passes through the groove 18 on the joint surface between the intake manifold 2 and the cylinder head 1 and from the connecting passage 20 in the center of the intake manifold 2 in the cylinder row direction to the center hole 32 of the gasket 28. Through the end hole 33 of the gasket 28 provided between the first and second cylinders and between the third and fourth cylinders. Into the groove 15 on the side of the pedestal 12 and thus discharged into the branch pipes 2a to 2d from the EGR gas discharge passage holes 24a to 24d provided in the intermediate portions in the axial direction of the branch pipes 2a to 2d corresponding to the cylinders. Is done.
[0019]
On the other hand, the blow-by gas that has flowed into the blow-by gas distribution passage 29 is discharged through the blow-by gas discharge passage holes 22a to 22d and the recess 23 in the vicinity of the opening of the intake port corresponding to each cylinder of the cylinder head 1.
[0020]
The portion between the two grooves 25 and 26 in the lid member 27 and the portion corresponding to this of the gasket 28 are opened so as to open the gap 13 formed between the two bases 11 and 12 upward. You may let them. If it does in this way, since it becomes easy to distribute | circulate air through the space | gap 13, the relaxation effect | action that the heat | fever of EGR gas is transmitted to blow-by gas can be improved further.
[0021]
【The invention's effect】
As described in detail above, according to the configuration of the first aspect of the present invention, the EGR gas distribution passage and the blow-by gas distribution passage are integrally formed on the upper surface of the intake manifold, and the EGR gas is discharged from the discharge port into each intake pipe. Since the blow-by gas is discharged to the downstream side of the intake air, it is possible to prevent carbon from adhering around the EGR gas outlet, and to maintain low-pollution and fuel-efficient performance over a long period of time. Has a great effect. In addition, since the air layer formed between the EGR gas distribution passage and the blow-by gas distribution passage reduces the heat of the relatively high-temperature EGR gas to the blow-by gas with a simple structure. Further, it is possible to suppress carbonization of the oil mist in the blow-by gas, and to obtain a further effect in preventing clogging of the passage.
[Brief description of the drawings]
FIG. 1 is a perspective view of an intake system to which the present invention is applied. FIG. 2 is a top view of an intake manifold according to the present invention. FIG. 3 is an end view of a joint surface of the intake manifold shown in FIG. 2 is a sectional view taken along line IV-IV in FIG. 2 with the member attached. FIG. 5 is a sectional view taken along line V-V in FIG. 2 with the lid member attached. Sectional view along line VI-VI in Fig. 2 in the state [Explanation of symbols]
2 Intake manifolds 2a to 2d Branch pipes 11 and 12 Base 13 Air gaps 14 and 15 Grooves 22a to 22d Blow-by gas discharge passage holes 24a to 24d EGR gas discharge passage holes 25 and 26 Groove 27 Lid member 29 Blow-by gas distribution passage 30 EGR gas distribution aisle

Claims (1)

An intake device for a multi-cylinder engine,
On the upper surface of the plurality of branch pipes connected to the intake port of each cylinder, two pedestals are provided that have grooves extending in the cylinder row direction across the adjacent branch pipes and having open upper surfaces. A lid member having two grooves corresponding to each of the grooves formed on the inner surface is fixed to the upper surfaces of the two pedestals to form individually independent EGR gas distribution passages and blow-by gas distribution passages;
Discharge passage holes into the branch pipes of the EGR gas distribution passage are arranged on the intake upstream side of the discharge passage holes into the branch pipes of the blow-by gas distribution passage, and an upper surface of the branch pipe, the pedestal, and the An air intake apparatus for a multi-cylinder engine, wherein a gap for forming an air layer is provided between the lid member and the lid member .

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