JP2018003655A - Intake manifold for multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly distribute an introduced purge gas to each cylinder by a simple structure, in an intake manifold.SOLUTION: An intake manifold has a structure in which two resin-made members 1, 2 are overlapped and joined to each other, and has a surge tank 3 and a plurality of intake outlet passages 4, 5 and 6 which are branched from the surge tank. A purge gas and intake air are introduced into one end part 7 of the surge tank 3. An auxiliary passage 15 for introducing the purge gas has a grooved discharge port 17 which is formed in the surge tank 3. A part of the surge gas is erected while forming a vortex flow 26 at a point of the discharge port 17, rides on a branch flow 24 of the intake air, and flows into the first intake outlet passage 4. Since the purge gas which flows straight in the discharge port 17 is protected by an outer wall 19, the purge gas is discharged from the discharge port 17, rises on a straight flow 23 of the intake air, is branched to the other intake outlet passage, and flows therein. Since the discharge port 17 is integrally formed at the member 1, the structure is simplified, and a cost can be suppressed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a surge tank integrated intake manifold fixed to a cylinder head of a multi-cylinder internal combustion engine, and more particularly to a type of intake manifold in which an auxiliary gas such as a fuel purge gas is introduced into a surge tank. It is.

  In passenger cars, the engine room is generally provided at the front and the fuel tank is provided below the rear vehicle. However, the fuel tank vaporizes, so the vaporized fuel is collected by the canister. Is introduced into the intake system as purge gas.

  When introducing the purge gas into the intake system, it is required to distribute the purge gas as evenly as possible to the cylinders. If the distribution becomes too uneven, the air-fuel ratio will deviate greatly from the set value, which is Exhaust gas components may not comply with the regulation values due to complete combustion, blow-by gas may increase due to fuel covering, and engine stall may occur in extreme cases.

  Therefore, a measure is taken to distribute the purge gas to each cylinder as evenly as possible. As an example, Patent Document 1 discloses an intake manifold having an intake inlet at one end of a surge tank, and an outlet at one end of the surge tank. It is disclosed that an L-shaped introduction member having an opening opened toward the other end of the surge tank is disposed.

  In Patent Document 1, an intake outlet passage for distributing intake air to each cylinder is directed in a direction orthogonal to the longitudinal direction of the surge tank, and an introduction member that discharges purge gas is upstream of the group of intake outlet passages. Is located.

JP 2001-152984 A

  In Patent Document 1, the purge gas outlet is only directed to the other end of the surge tank, and the purge gas ejection direction and the flow direction of the intake air coincide with each other. It is understood that the gas tends to be carried to the other end portion of the surge tank, and it is estimated that a large amount of purge gas flows into the most downstream intake outlet passage located at the other end portion of the surge tank. For this reason, it is doubtful whether the purpose of equal distribution can be sufficiently achieved.

  On the other hand, as a modified form of Patent Document 1, it is possible to adopt a form in which the intake inlet of the surge tank is positioned at one end of the surge tank and the intake inlet is opened in a direction perpendicular to the longitudinal direction of the surge tank. In this case, since the direction of the intake air is changed at one end of the surge tank, the straightness of the intake air is reduced. As a result, it can be said that the dispersibility of the intake air to each intake outlet passage is improved.

  However, in this case, since the purge gas outlet is located at one end of the surge tank, the purge gas is easy to ride the flow of intake air toward the most upstream intake outlet passage near the one end, Therefore, contrary to Patent Document 1, the purge gas tends to flow in a large amount in the intake outlet passage located on the most upstream side, and it is estimated that even distribution is difficult to achieve in this case as well.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an intake manifold capable of distributing auxiliary gas such as fuel purge gas to the intake outlet passage as evenly as possible.

The intake manifold of the present invention is
“A surge tank that opens an intake inlet at one end and the intake air flows from one end to the other end is integrally provided with a plurality of intake outlet passages that diverge and discharge the intake air flowing into the surge tank. And
Each of the intake outlet passages is directed in a direction crossing a line connecting one end and the other end of the surge tank,
With one end of the surge tank facing the other end, the one end of the surge tank protrudes forward from the group of the intake outlet passages, and one end of the surge tank has a fuel purge gas or other An auxiliary passage is formed to introduce auxiliary gas into the surge tank. "
This is the basic configuration.

  In the above basic configuration, the auxiliary passage has a groove-like discharge port that enters the inside of the surge tank, and the discharge port includes an auxiliary gas that travels straight through the discharge port and the other of the surge tank. The tip is opened toward the straight direction of the auxiliary gas so as to eject toward the end.

  In the present invention, in order to increase the dispersibility of the intake air, it is preferable to suppress the straightness within the surge tank as much as possible.To that end, the intake air is directed in a direction perpendicular to the longitudinal direction of the surge tank. It is preferable to change the direction at one end of the surge tank. In this case, the discharge port of the auxiliary passage is preferably arranged so that the intake air hits after the direction is changed.

  The present invention is suitable as a fuel purge gas introduction means, but can also be applied to the introduction of blow-by gas (PCV gas) or EGR gas.

  The auxiliary gas is dissipated from the discharge port of the auxiliary passage to the surge tank, but the discharge port has a groove shape having two walls and the tip is opened toward the straight direction of the auxiliary gas. Auxiliary gas that has flowed, a straight flow that goes straight through the discharge port toward the other end of the surge tank, and a direction change flow that changes direction at the groove and is diffused into the surge tank from between the two walls. Divide into Actually, the inventor of the present application analyzed that it was confirmed that the flow was divided into these two flows, and the direction change flow was a vortex and the flow velocity was also reduced.

  On the other hand, since the intake inlet is located at one end of the surge tank, the intake air flowing in from the intake inlet flows to the intake outlet passage located at the most upstream part and the other end of the surge tank. It is divided into a flow straight ahead and the straight flow branches in the middle and sequentially flows into other intake outlet passages.

  Of the auxiliary gas, the direction change flow rising without reaching the tip of the discharge port is exposed to the branch flow toward the most upstream intake outlet passage in the intake flow, and the most upstream intake outlet passage The auxiliary gas that travels straight through the discharge port of the auxiliary passage is protected by the wall against the branch flow toward the intake outlet passage on the most upstream side of the intake air. Without going on, it is released as a straight flow into the surge tank, but this straight flow of the auxiliary gas rides on the straight flow of the intake air and mixes with the intake air, and then branches into other intake outlet passages and flows in. I will do it. Therefore, the auxiliary gas can be distributed as evenly as possible to the intake and outlet passages.

  Nowadays, the intake manifold for automobiles often adopts a molded product of synthetic resin, but the discharge port of the auxiliary passage is troublesome by forming a groove in the die cutting direction at the time of injection molding. It can be formed easily without requiring. Therefore, when applied to a resin intake manifold, the dispersibility of the auxiliary gas can be improved while the cost is reduced with a simple structure.

  When the intake manifold is made of resin, the mold for molding has a so-called cavity and core as a basic structure, and the auxiliary passage is formed with a hole by, for example, a slide pin provided in the cabinet. If the tip is only open as a round hole, the opening area of the tip may become uneven due to the formation of a burr-like film on the edge due to the contact condition of the tip of the slide pin, etc. In addition, dispersion of auxiliary gas dispersibility occurs.

  On the other hand, if the tip of the auxiliary passage is formed in a groove-like discharge port as in the present invention, the opening area of the discharge port can be made constant regardless of the movement error of the slide pin. There is also an advantage that the quality can be stabilized.

  In the case of an internal combustion engine equipped with a turbocharger, the surge tank has a positive pressure in a supercharged state. Therefore, when introducing purge gas or PCV gas, for example, in a deceleration region or an idling region. Therefore, a large amount of purge gas or PCV gas tends to be introduced at once, and a problem in the case of non-uniform distribution appears significantly. Then, even if the amount of auxiliary gas such as purge gas or PCV gas is large, it can be evenly distributed to each intake outlet passage (each cylinder), and thus it can be said to be particularly valuable in an internal combustion engine equipped with a turbocharger.

It is a perspective view of the lower member of the intake manifold which concerns on embodiment. It is a perspective view of the upper member of the intake manifold which concerns on embodiment. (A) is a partial plan view of the intake manifold as seen from the inflow direction of intake air, and (B) is a side view of the intake manifold. (A) is a principal part perspective view, (B) is a top view of the principal part seen from the inflow direction of intake air, (C) is a principal part enlarged view of (B).

(1) Structure of Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to an intake manifold in which purge gas introducing means is embodied. The intake manifold is made of synthetic resin, and has a hollow structure formed by overlapping the lower member 1 shown in FIG. 1 and the upper member 2 shown in FIG. Therefore, the upper and lower members 1 and 2 have a shell structure that is recessed in the facing direction.

  The intake manifold of this embodiment is for three cylinders, and the intake manifold is directly fixed to a cylinder head (not shown). For this reason, it is long in the cylinder row direction. Therefore, in order to indicate the direction, as shown in FIGS. 1, 2, and 3A, for convenience, the longitudinal direction of the intake manifold is called the front-rear direction, and the direction orthogonal to the intake side of the cylinder head is It will be called a direction.

  The intake manifold includes a surge tank 3 that is long in the front-rear direction, and first to third intake outlet passages 4, 5, and 6 branched from the surge tank 3. Of course, the surge tank 3 and the intake outlet passages 4, 5 and 6 are configured by overlapping and joining the upper and lower members 1 and 2, and the intake outlet passages 4, 5, and 6 are terminated. Each is divided into two exit holes near the section.

  One end portion (front end portion) 7 of the surge tank 3 is a protruding portion that projects forward from the group of intake outlet passages 4, 5, 6, and a throttle body (not shown) is formed at one end portion of the upper member 2. ) Is fixed to protrude upward substantially, and an intake inlet 9 is opened in the throttle receiving seat 8. One end portion 7 of the surge tank 3 is rounded in plan view and side view, but the intake inlet 9 is connected to one end portion of the surge tank 3 as shown in FIG. , It is displaced away from the cylinder head.

  As shown in FIG. 1, the lower member 1 is formed with a flange 10 fixed to the cylinder head, and the outlet holes of the intake outlet passages 4, 5, 6 are formed in the flange 10. A plurality of bolt insertion holes 11 are formed in the flange 10.

  The intake outlet passages 4, 5, and 6 are referred to as a first intake outlet passage 4, a second intake outlet passage 5, and a third intake outlet passage 6 in order from the one closest to the one end portion 7, as shown in FIG. Between the first intake outlet passage 4 and the second intake outlet passage 5, there is provided a protruding portion 12 that protrudes slightly toward the surge tank 3 from the starting end thereof. Therefore, the protrusion 12 is curved when viewed from the plane direction, and has a guide function for guiding the intake air into the first intake outlet passage 4.

  As described above, the one end portion 7 of the lower member 1 is a protruding portion that is rounded in a substantially plan view. Of the peripheral wall 14 that constitutes the one end portion 7, the inner portion 14a that is closer to the cylinder head side. In addition, an auxiliary passage 15 for introducing a purge gas as an example of the auxiliary gas is formed. The auxiliary passage 15 has a joint cylinder 16 protruding outside the lower member 1 and a discharge port 17 exposed inside the surge tank 3, and a hose is connected to the joint cylinder 16.

  On the other hand, the discharge port 17 is formed on the upper surface of the block portion 18 connected to the inner periphery and the bottom of the lower member 1, has a groove shape opened substantially upward, and the tip thereof is the surge tank 3. Open to the inside. Accordingly, the discharge port 17 has left and right walls 19 and 20. A base end 17a of the discharge port 17 enters the inside of the surge tank 3 by a slightly smaller size than the peripheral wall 14 of the lower member 1, and a hole 21 constituting a gas passage is formed in the base end 17a. Further, the tip of the discharge port 17 opens toward the inside of the surge tank 3.

  As can be easily understood from FIG. 1, the auxiliary passage 15 has a shape that is long in the front-rear direction as a whole, but the longitudinal direction of the auxiliary passage 15 (so that the purge gas is jetted slightly obliquely toward the surge tank 3 ( Alternatively, the direction of the discharge port 17 is slightly inclined with respect to the longitudinal direction of the surge tank 3 in plan view.

  The discharge port 17 is composed of two walls 19 and 20. For convenience, the one far from the cylinder head is called the outer wall 19, and the one near the cylinder head is called the inner wall 20. The inner wall 20 can be integrated with the peripheral wall 14 of the lower member 1 (the discharge port 17 is formed between the peripheral wall 14 and the outer wall 19).

  The block portion 18 is stepped slightly lower than the end face of the peripheral wall 14. Moreover, the front-end | tip part which has entered the inside of the surge tank 3 among the block parts 18 has an inclined surface 18a whose height decreases in the purge gas ejection direction. The block portion 18 and the discharge port 17 are integrally formed when the lower member 1 is manufactured by an injection molding method. Therefore, the discharge port 17 is opened in the direction of the mold drawing direction (mold opening direction) 22 shown in FIG.

(2) Operation of Embodiment In this embodiment, since the intake inlet 9 is opened in a direction orthogonal to the longitudinal direction of the surge tank 3, the intake air flowing into the surge tank 3 from the intake inlet 9 is at one end 7. As shown by the arrow 23 in FIG. 4 (B), the air flow is converted into a straight flow that flows from one end 7 toward the other end. Divide toward 4, 5 and 6.

  However, the one end portion 7 and the first intake outlet passage 4 are close to each other, and the intake inlet 9 is shifted away from the cylinder head with respect to the one end portion 7, so that the intake air is closer to the cylinder head side. By flowing into the one end portion 7 as shown in FIG. 4B, a branch flow flows into the first intake outlet passage 4 as indicated by an arrow 24 in FIG.

  That is, the intake air flowing into the one end portion 7 from the intake inlet 9 is divided into a straight flow 23 toward the other end portion of the surge tank 3 and a branch flow 24 toward the first intake outlet passage 4 at the one end portion 7. Show a trend.

  The branch flow 24 toward the first intake outlet passage 4 tends to flow (guided) along the inner portion 14 a of the peripheral wall 14 in the lower member 1, but the auxiliary passage 15 has a tendency to flow in the inner portion 14 a of the peripheral wall 14. Therefore, when the auxiliary passage 15 is merely open to the inner portion 14a of the peripheral wall, most of the purge gas rides on the branch flow 24 and flows into the first intake outlet passage 4, There is a high risk that the fuel will be excessively rich in one cylinder.

  On the other hand, in this embodiment, since the auxiliary passage 15 has a groove shape having the outer wall 19, the purge gas that travels straight inside the auxiliary passage 15 is protected by the outer wall 19, and does not enter the branch flow 24. It becomes a straight flow 25 discharged into the tank 3 and rides on the straight flow 23 of the intake air, so that the distribution of the purge gas to the second intake outlet passage 5 and the third intake outlet passage 6 is made uniform. It can be improved.

  On the other hand, since the discharge port 17 has a groove shape, a part of the purge gas becomes a vortex as shown by an arrow 26 in FIGS. 4B and 4C due to the expansion action when the purge gas is ejected from the hole 21. A phenomenon of rising upward from the discharge port 17 has occurred, and the purge gas that has risen as the vortex flow 26 rides on the branch flow 24 of the intake air and flows into the first intake outlet passage 4.

  In this way, at the location of the groove-like discharge port 17, a part of the purge gas can rise as a vortex 26 and the other part can go straight and be placed on the straight flow 23 of the intake air. As a result, even if the amount of purge gas is large, it is possible to prevent the fuel from becoming rich in a specific cylinder and to adversely affect exhaust component deterioration. Can be prevented.

  In the internal combustion engine to which the present embodiment is applied, the valve 27 of the throttle valve rotates about the longitudinal longitudinal axis as shown by a one-dot chain line in FIG. For this reason, the intake air tends to be directed toward the inner portion 14 a of the peripheral wall 14 of the one end portion 7, and the direction is smoothly changed at the rounded one end portion 7, but the discharge port 17 has the outer wall 19. Therefore, even when the intake air is directed toward the discharge port 17, the purge gas that goes straight inside the groove can be put on the straight flow 23 of the intake air. Accordingly, it is possible to improve the distribution of the purge gas without impairing the smoothness of the intake air flow.

  Although the above embodiment is applied to the distribution of the purge gas, it can also be applied to the distribution of other auxiliary gases such as PCV gas and EGR gas. Further, although not so much as described, the present invention can be applied to other multi-cylinder internal combustion engines having two cylinders or four or more cylinders. The intake inlet can be opened downward, for example. The intake manifold may have a structure in which three or more members are stacked and joined.

  The present invention can be embodied in an intake manifold. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Plastic lower member which comprises an intake manifold 2 Plastic upper member which comprises an intake manifold 3 Surge tank 4-6 Intake outlet channel | path 7 One end part 9 Intake inlet 10 Flange 14 Perimeter wall 15 Auxiliary channel | path 16 Joint pipe | tube 17 Discharge port 17a Base end 18 Block portion 19 Outlet wall outer wall 20 Outlet port inner wall 23 Intake straight flow 24 Intake branch flow 25 Purge gas straight flow 26 Purge gas direction change flow (vortex flow)

Claims (1)

A plurality of intake outlet passages for branching and discharging intake air flowing into the surge tank are integrally provided in a surge tank in which an intake inlet is opened at one end portion and intake air flows from one end portion toward the other end portion. And
Each of the intake outlet passages is directed in a direction crossing a line connecting one end and the other end of the surge tank,
With one end of the surge tank facing the other end, the one end of the surge tank protrudes forward from the group of the intake outlet passages, and one end of the surge tank has a fuel purge gas or other An auxiliary passage for introducing auxiliary gas into the surge tank is formed,
The auxiliary passage has a groove-like discharge port that has entered the inside of the surge tank, and the discharge port discharges auxiliary gas that has traveled straight through the discharge port toward the other end of the surge tank. The tip is open toward the straight direction of the auxiliary gas,
Intake manifold for multi-cylinder internal combustion engines.

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