JP6754631B2 - Intake manifold for multi-cylinder internal combustion engine - Google Patents

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 specifically, to a type of intake manifold in which an auxiliary gas such as a fuel purge gas is introduced into the surge tank. Is.

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

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

Therefore, measures have been taken to distribute the purge gas to each cylinder as evenly as possible. As an example, in Patent Document 1, in an intake manifold in which an intake inlet is provided at one end of a surge tank, an outlet is provided at one end of the surge tank. It is disclosed that an L-shaped introduction member is arranged so as to open toward the other end of the surge tank.

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

Japanese Unexamined Patent Publication No. 2001-152988

In Patent Document 1, the outlet of the purge gas only faces the other end of the surge tank, and the ejection direction of the purge gas coincides with the flow direction of the intake air, so that the purge gas has a straightforward intake flow. It is understood that the purge gas tends to be carried to the other end of the surge tank by riding on it, and it is presumed that a large amount of purge gas flows into the most downstream intake outlet passage located at the other end of the surge tank. Therefore, it is doubtful whether the purpose of even distribution can be sufficiently achieved.

On the other hand, as a modified form of Patent Document 1, it is also possible to adopt a form in which the intake inlet of the surge tank is located at one end of the surge tank and the intake inlet is opened in a direction orthogonal to the longitudinal direction of the surge tank. In this case, since the intake air changes direction at one end of the surge tank, the straightness of the intake air is lowered, and as a result, the dispersion of the intake air to each intake outlet passage is improved.

However, in this case, since the outlet of the purge gas is located at one end of the surge tank, the purge gas can easily get on the flow of intake air toward the most upstream intake outlet passage near the 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 presumed that it is difficult to achieve even distribution in this case as well.

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

The intake manifold of the present invention
"A plurality of surge tanks opened inside the surge tank so that the intake air that has flowed into the surge tank is branched and discharged into a surge tank in which the intake air inlet is opened at one end and the intake air flows from one end to the other end. The intake outlet passages of the above are integrally provided side by side in the front-rear direction connecting the one end and the other end.
In addition, an overhanging portion protruding from the group of the intake outlet passages is formed at one end of the surge tank, and the intake inlet and the fuel purge gas or other auxiliary gas are introduced into the surge tank at the overhanging portion. Auxiliary passages and auxiliary passages are formed to
It is a basic configuration.

And in the above basic configuration
"The surge tank and the overhanging portion are formed hollow by joining one resin member in which the intake inlet is formed and the other resin member in which the auxiliary passage is formed.
While the intake inlet is open toward the other resin member with the space of the overhanging portion interposed therebetween,
The other resin member has a peripheral wall constituting the overhanging portion, and an inwardly facing block portion located on the inner peripheral surface of the peripheral wall with the internal space of the overhanging portion sandwiched between the intake inlet and the intake port. There are formed, the distal end surface facing the member of the one of said block portion, the discharge port of the auxiliary passage is formed in the form of a groove, the groove of the discharge port, the discharge port the as straight and auxiliary gas is ejected toward the side of the other end of the surge tank, the tip pointing in the flow direction ahead of the auxiliary gas and is opened toward the other end of the surge tank "
It has the feature.

The present invention is suitable as a means for introducing a fuel purge gas, 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 is in the form of a groove having two walls and is open toward the other end of the surge tank. Auxiliary gas that has flowed through the passage, a straight flow that goes straight through the discharge port toward the other end of the surge tank, and a direction change that changes direction at the groove and dissipates into the surge tank from between the two walls. Divide into the stream. In fact, as a result of analysis by the inventor of the present application, it was confirmed that the flow was divided into these two flows, and the directional change flow became a whirlpool and the flow velocity was also reduced.

On the other hand, since the intake inlet is located at the overhanging part of the surge tank, the intake air that has flowed into the overhanging part from the intake inlet is branched to the intake outlet passage located at the most upstream part, and the surge tank and other parts. Divided into a flow that goes straight toward the end, the flow that goes straight branches off in the middle and sequentially flows into another intake outlet passage.

Then, of the auxiliary gas, the directional change flow that rises without reaching the tip of the discharge port is exposed to the branch flow toward the intake outlet passage on the most upstream side of the intake flow, and is exposed to the intake outlet passage on the most upstream side. The auxiliary gas that flows straight through the discharge port of the auxiliary passage is protected by a wall against the branch flow toward the intake outlet passage on the most upstream side of the intake air, so that the auxiliary gas flows into the intake branch flow. The straight flow of the auxiliary gas is released into the surge tank as a straight flow without riding, but the straight flow of the auxiliary gas rides on the straight flow of the intake air, mixes with the intake air, and sequentially branches into other intake outlet passages. I will do it. Therefore, the auxiliary gas can be distributed and flowed to each intake outlet passage as evenly as possible.

By the way, in recent years, automobile intake manifolds often use synthetic resin molded products, but in the present invention, the discharge port of the auxiliary passage has a form in which a groove is opened in the die-cutting direction during injection molding. and for which, it can be easily formed without requiring troublesome. Therefore, when applied to a resin intake manifold, it is possible to improve the dispersibility of the auxiliary gas while suppressing the cost with a simple structure.

When the intake manifold is made of resin, the molding die is basically composed of a so-called cavity and a core, and holes are formed in the auxiliary passage by, for example, a slide pin provided in the cavity. If the tip is merely opened as a round hole, the opening area of the tip may be 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. , The dissipative property of the auxiliary gas varies.

On the other hand, if the discharge port of the auxiliary passage is formed in the form of a groove on the tip surface of the block portion 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 by eliminating the variation of each.

In the case of an internal combustion engine equipped with a turbocharger, the pressure inside the surge tank is positive in the supercharged state, so when introducing purge gas or PCV gas, for example, in the deceleration region or idling region. Since it must be performed in a region where the turbocharger is not supercharged, a large amount of purge gas or PCV gas tends to be introduced at once, and a problem when the distribution is uneven appears prominently. 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), so that it can be said that it is 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 perspective view of the main part, (B) is a plan view of the main part as seen from the inflow direction of the intake air, and (C) is an enlarged view of the main part of (B).

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

The intake manifold of this embodiment is for three cylinders, and the intake manifold is directly fixed to a cylinder head (not shown). Therefore, the shape is long in the cylinder row direction. Therefore, in order to show the direction, as clearly shown in FIGS. 1, 2, and 3 (A), for convenience, the longitudinal direction connecting one end and the other end of the intake manifold is called the front-rear direction, and the intake air of the cylinder head is called. The direction orthogonal to the side surface is called the left-right direction.

The intake manifold has a surge tank 3 long in the front-rear direction and first to third intake outlet passages 4, 5 and 6 branched from the surge tank 3. As a matter of course, the surge tank 3 and the intake outlet passages 4, 5 and 6 are formed by superimposing and joining the upper and lower members 1 and 2, and the intake outlet passages 4, 5 and 6 are terminated. It is divided into two outlet holes near the section.

One end (front end) of the surge tank 3 is an overhanging portion 7 protruding toward the front of the group of intake outlet passages 4, 5 and 6, and a throttle body (shown) is provided on the overhanging portion 7 of the upper member 2. The throttle receiving seat 8 to which the throttle receiving seat 8 is fixed is projected substantially upward, and the intake inlet 9 is opened in the throttle receiving seat 8. Therefore, in the present embodiment, in relation to the claims, the upper member 2 corresponds to one resin member, and the lower member 1 corresponds to the other resin member.
The overhanging portion 7 of the surge tank 3 has a rounded shape in both a plan view and a side view, but as shown in FIG. 4B, the intake inlet 9 has a shape with respect to the overhanging portion 7 of the surge tank 3. Therefore, it is displaced in the direction 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 outlet holes of the intake outlet passages 4, 5 and 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 overhanging portion (one end portion) 7. As shown in FIG. 1, between the first intake outlet passage 4 and the second intake outlet passage 5, a protruding portion 12 is provided so as to project slightly toward the surge tank 3 from the start end thereof. Therefore, the protruding portion 12 is curved when viewed from the plane direction, and has a guide function for inviting the intake air into the first intake outlet passage 4.

As described above, the overhanging portion 7 of the lower member 1 has a rounded shape in a substantially plan view, and the inner portion 14a of the peripheral wall 14 constituting the overhanging portion 7 is closer to the cylinder head side. , An auxiliary passage 15 for introducing a purge gas as an example of the auxiliary gas is formed. Since the auxiliary passage 15 is formed in the overhanging portion 7 of the lower member 1 while the intake inlet 9 is formed in the overhanging portion 7 of the upper member 2, the auxiliary passage 15 takes in air with the space of the overhanging portion 7 in between. It is located on the opposite side of the entrance 9.
The auxiliary passage 15 has a joint cylinder 16 projecting to the outside of 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 circumference and the bottom of the lower member 1, and is a groove that opens substantially upward . Therefore, the discharge port 17 has left and right walls 19 and 20. The base end 17a of the discharge port 17 enters the inside of the surge tank 3 by a size slightly larger than the peripheral wall 14 of the lower member 1, and the base end 17a has a hole 21 forming a gas passage. Further, the tip end (front end facing the flow direction of the purge gas) 17b of the discharge port 17 is also open toward the rear end of the surge tank 3.

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

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

The block portion 18 is stepped down slightly lower than the end face of the peripheral wall 14. Further, the tip portion of the block portion 18 that has entered the inside of the surge tank 3 is an inclined surface 18a whose height decreases in the direction in which the purge gas is ejected. 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 opens in the die cutting direction (mold opening direction) 22 shown in FIG. 4 (A).

(2). Operation of the Embodiment In the present embodiment, since the intake inlet 9 opens in a direction orthogonal to the longitudinal direction of the surge tank 3, the intake air that has flowed into the overhanging portion 7 of the surge tank 3 from the intake inlet 9 Is changed in the direction of approximately 90 ° inside the overhanging portion 7, and basically, as shown by the arrow of reference numeral 23 in FIG. 4B, from the overhanging portion 7 to the other end portion (rear end portion) . It becomes a straight flow flowing toward, and is divided toward each intake outlet passages 4, 5 and 6.

However, the overhanging portion 7 and the first intake outlet passage 4 are close to each other, and the intake inlet 9 is displaced to the side far from the cylinder head with respect to the overhanging portion 7 , so that the intake air is closer to the cylinder head side. As shown by the arrow of reference numeral 24 in FIG. 4B, it also becomes a branch flow that flows into the first intake outlet passage 4 by flowing into the overhanging portion 7 .

That is, the intake air that has flowed into the one end 7 from the intake inlet 9 is divided into a straight flow 23 toward the other end of the surge tank 3 and a branch flow 24 toward the first intake outlet passage 4 at the one end 7. Shows a tendency.

Then, the branch flow 24 toward the first intake outlet passage 4 tends to flow (guided) along the inner portion 14a of the peripheral wall 14 in the lower member 1, while the auxiliary passage 15 tends to flow along the inner portion 14a of the peripheral wall 14. If the auxiliary passage 15 is merely opened to the inner portion 14a of the peripheral wall because it is provided at the location, most of the purge gas rides on the branch flow 24 and flows into the first intake outlet passage 4, and the first There is a high possibility that the fuel will be excessively rich in one cylinder.

On the other hand, in the present embodiment, since the auxiliary passage 15 has a groove shape having an outer wall 19, the purge gas traveling straight inside the auxiliary passage 15 is protected by the outer wall 19 and surges without riding on the branch flow 24. It becomes the straight flow 25 discharged into the tank 3 and rides on the straight flow 23 of the intake air, thereby making the distribution of the purge gas uniform to the second intake outlet passage 5 and the third intake outlet passage 6. Can be improved.

On the other hand, since the discharge port 17 has a groove shape, a part of the purge gas becomes a whirlpool as shown by arrows 26 in FIGS. 4 (B) and 4 (C) 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 rising as the whirlpool 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 groove-shaped discharge port 17, a part of the purge gas can be raised as a whirlpool 26, and the other part can be made to go straight and put on the straight flow 23 of the intake air. It can be distributed as evenly as possible to the intake outlet passages 4, 5 and 6, and 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 adversely affect the exhaust component deterioration. Can be prevented.

In the internal combustion engine to which the present embodiment is applied, as shown by the alternate long and short dash line in FIG. 4B, the valve 27 of the throttle valve rotates around the axial center of the front-rear longitudinal direction. Therefore, intake air, exhibits a tendency toward the inside portion 14a of the peripheral wall 14 of the overhanging portion 7 will be generally redirecting smoothly in overhanging portion 7 a rounded, the discharge port 17 has an outer wall 19 Therefore, even if the intake air is directed toward the discharge port 17, the purge gas that travels straight inside the groove can be put on the straight flow 23 of the intake air. Therefore, the distributability of the purge gas can be improved without impairing the smoothness of the intake flow.

Although the above embodiment has been applied to the distribution of purge gas, it can also be applied to the distribution of other auxiliary gases such as PCV gas and EGR gas. Further, although not to mention dare, the present invention can be applied to other multi-cylinder internal combustion engines having two or four cylinders or more. 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.

1 Resin lower member (the other resin member) that constitutes the intake manifold
2 Resin upper member (one resin member) that constitutes the intake manifold
3 Surge tank 4 to 6 Intake outlet passage 7 Overhang (one end)
9 Intake inlet 10 Flange 14 Peripheral wall 15 Auxiliary passage 16 Joint cylinder 17 Discharge port 17a Base end of discharge port
17b Tip of discharge port 18 Block 19 Outer wall of discharge port 20 Inner wall of discharge port 23 Straight flow of intake air 24 Branch flow of intake water 25 Straight flow of purge gas 26 Direction change flow of purge gas (vortex flow)

Claims (1)

A plurality of surge tanks opened inside the surge tank so that the intake air that has flowed into the surge tank is branched and discharged into a surge tank in which the intake air inlet is opened at one end and the intake air flows from one end to the other end. The intake outlet passages are integrally provided side by side in the front-rear direction connecting the one end and the other end.
In addition, an overhanging portion protruding from the group of the intake outlet passages is formed at one end of the surge tank, and the intake inlet and the fuel purge gas or other auxiliary gas are introduced into the surge tank at the overhanging portion. It is a configuration in which an auxiliary passage is formed.
The surge tank and the overhanging portion are formed hollow by joining one resin member in which the intake inlet is formed and the other resin member in which the auxiliary passage is formed.
While the intake inlet is open toward the other resin member with the space of the overhanging portion interposed therebetween,
The other resin member has a peripheral wall constituting the overhanging portion, and an inwardly facing block portion located on the inner peripheral surface of the peripheral wall with the internal space of the overhanging portion sandwiched between the intake inlet and the intake port. There are formed, the distal end surface facing the member of the one of said block portion, the discharge port of the auxiliary passage is formed in the form of a groove, the groove of the discharge port, the discharge port straight the auxiliary gas is to ejected toward the side of the other end of the surge tank, and a distal end facing the flow direction ahead of the auxiliary gas is opened toward the other end of the surge tank,
Intake manifold for multi-cylinder internal combustion engine.

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