JP7107911B2 - Intake manifold for automotive internal combustion engine - Google Patents

Description

The present invention relates to an intake manifold for an internal combustion engine for automobiles.

2. Description of the Related Art In internal combustion engines such as vehicle internal combustion engines, resin intake manifolds are widely used. In this case, the resin-made intake manifold is composed of a plurality of members in terms of die-cutting, and the members are integrally joined by welding or the like. Further, the intake manifold often has a structure in which a surge tank and a group of branch pipes are integrated.

In the internal combustion engine, the blow-by gas blown into the crank chamber is returned to the intake system, and the exhaust gas (EGR gas) is recirculated to the intake system. There are many. In addition, automobiles use a brake booster that utilizes the negative pressure of the intake air to amplify the braking force, and the negative pressure for operating the brake booster is taken from the surge tank of the intake manifold. many. That is, in many cases, the negative pressure extraction port for the brake booster is opened in the surge tank.

In this way, when the surge tank is provided with the gas inlet and the negative pressure outlet, if the negative pressure outlet and the gas inlet are located close to each other, for example, the moisture contained in the blow-by gas will be removed. It may condense and freeze inside the negative pressure outlet or negative pressure outlet hose, causing malfunction of the brake booster. Regarding this point, it can be said that the negative pressure outlet and the gas inlet should be formed at distant locations, but due to functional restrictions, the negative pressure outlet and the gas inlet must be formed close to each other. may not be.

For example, in a right-hand drive vehicle with a horizontal engine, in order to shorten the length of the tube that connects the brake booster and the surge tank as much as possible, the negative pressure outlet should be placed at the right end of the surge tank as seen from the driver. On the other hand, in providing an oil separator passage for removing oil from the blow-by gas in the head cover, the blow-by gas is provided near the right end of the head cover in order to ensure oil collection by lengthening the oil separator passage. In some cases, an outlet must be provided, and in this case, in order to shorten the PCV passage that connects the head cover and the surge tank and simplify the structure, the PCV passage must be connected to a portion near the right end of the surge tank. , the problem of moisture intrusion into the negative pressure outlet as described above arises.

Regarding this point, Patent Document 1 discloses that a negative pressure outlet is provided in the end plate of one of two overlapping resin members, and a gas inlet is provided in the wall portion (end plate) of the other resin member. In the configuration in which the negative pressure outlet and the gas inlet are open in the same direction (crank axis direction), the negative pressure outlet is formed in a raised portion formed in the wall of one of the resin members and , forming a guide groove on the outer periphery of the ridge to guide the gas away from the negative pressure outlet.

Japanese Patent Application Laid-Open No. 2007-40142

If the negative pressure outlet and the gas inlet are open on the inner surface of the wall of the surge tank, condensed moisture will enter the negative pressure outlet along the inner surface of the wall if no countermeasures are taken. However, in Patent Literature 1, the negative pressure outlet is provided with a raised portion that protrudes in a stepped manner to prevent condensed water from flowing into the negative pressure outlet. Although it can be said that the inflow of condensed water to can be suppressed, it can be said that there is still room for improvement.

For example, since the intake air flows at high speed inside the surge tank, there is a possibility that the condensed water will ride on the intake air and flow into the negative pressure outlet. A measure to prevent condensate from entering the outlet is desired.

The present invention aims at improving such a situation.

The present invention relates to an intake manifold for an internal combustion engine for automobiles.
"A surge tank having an intake inlet formed at one end of both ends facing the crankshaft direction, and a group of branch pipes branched from the surge tank and connected at the tip to the intake port of the cylinder head. The surge tank is formed of two resin members superimposed and joined in a direction orthogonal to the crank axis,
Furthermore, a negative pressure outlet and a gas inlet are formed at the other end of the surge tank opposite to the intake inlet."
It has a basic configuration.

And in the invention of claim 1, in the above basic configuration,
"A pre-chamber is formed in one of the two resin members that constitute the surge tank, and is open in the overlapping direction of the resin members and communicates with the negative pressure outlet,
The gas inlet is formed to open in a direction crossing the opening direction of the auxiliary chamber ,
In addition, a rib plate is formed on the other resin member of the two resin members that constitute the surge tank, and enters into the pre-chamber to divide the pre-chamber into two chambers that are separated in the direction of the crankshaft axis.
configuration is added.

The invention of claim 2 is, in claim 1 ,
"The sub-chamber is formed by integrally providing an internal partition surrounding a part of the inner surface of one side wall of the one resin member,
The negative pressure outlet is open to the outside of the one side wall, and the gas inlet is open toward the internal partition wall, while the internal partition wall is exposed to the gas ejected from the gas inlet port. It is inflated in the opposite direction to the negative pressure outlet so that the
It is configured. Note that the word "inflate" can also be rephrased as "protrude" or "protrude."

In constructing a resin intake manifold with a plurality of resin members, if the branch passage is formed so as to wrap around the surge tank, it is necessary to stack three resin members to manufacture the intake manifold. The surge tank is formed of two of these resin members, and which of the two resin members should form the negative pressure outlet, the pre-chamber, and the gas inlet depends on the shape of the two resin members. should be considered and selected.

The negative pressure outlet, the pre-chamber, and the gas inlet may be formed in one resin member, or the pre-chamber and the negative pressure outlet may be formed in one resin member, and the gas flow in the other resin member may be controlled. It is also possible to form an inlet.

Gases that flow into the surge tank include blow-by gas, EGR gas, and vaporized fuel gas. Due to restrictions on the position, it may have to be formed near the negative pressure outlet, so the present invention is preferably configured as blow-by gas inflow suppression means.

In the present invention, since the opening direction of the gas inlet and the opening direction of the pre-chamber are different, the gas ejected from the gas inlet does not directly flow into the pre-chamber. In addition, since the intake inlet is open at one end of the surge tank, the intake air tends to flow from one end to the other end of the surge tank (that is, in the direction of the crankshaft). Since the superposition direction of is perpendicular to the crank axis, the pre-chamber also opens in the direction perpendicular to the crank axis, so that gas such as blow-by gas rides on the intake air and flows directly into the pre-chamber. no.

In this way, it is possible to prevent or significantly suppress the flow of gas such as blow-by gas into the pre-chamber. It can be prevented or greatly suppressed from flowing into the mouth.

Therefore, when the negative pressure outlet is connected to the brake booster, it is possible to ensure the operation of the brake booster even in a low temperature environment, thereby ensuring the safety of the automobile. In addition, if the gas inlet is for blow-by gas, a long oil separator passage is formed in the head cover to maintain high oil collection performance, and the blow-by gas outlet of the head cover and the inlet of the surge tank are separated. The distance can be shortened, the cost can be suppressed, and the flow of blow-by gas can be made smooth.

Also, the two resin members that make up the surge tank are molded using a mold that moves in the direction in which they overlap. , means that the pre-chamber is open in the moving direction of the mold, so that the pre-chamber can be easily formed without providing a slide mold. Therefore, the sub-chamber can be formed without incurring manufacturing problems.

Furthermore, according to the present invention, since the rib plate can further suppress the entry of intake air into the pre-chamber, it is possible to further suppress the entry of moisture into the negative pressure outlet. In addition, if the moisture mixed in the blow-by gas, etc., forms water droplets, the water droplets that fly on the intake air are atomized by hitting the rib plate to atomize the water droplets on the reflected flow of the intake air and into the surge tank. It is also possible to scatter the water, and in this respect as well, the effect of preventing moisture from entering the negative pressure outlet can be improved.

When the structure of claim 2 is adopted, the flow of gas can be diverted to the side opposite to the negative pressure outlet by using the internal partition wall that constitutes the pre-chamber. Absorption into the mouth can be prevented or greatly suppressed without complicating the structure.

As disclosed in Patent Document 1, the negative pressure outlet for the brake booster is often provided on the wall of the surge tank. As a method of preventing entry, instead of providing a pre-chamber, it is also possible to provide a barrier plate in the vicinity of the wall. However, in this case, if the distance between the wall and the barrier plate is narrowed, a thin portion is formed in the mold for molding, resulting in a problem of reduced durability of the mold.

On the other hand, in the present invention, the part of the mold that forms the pre-chamber has a columnar structure, but since the pre-chamber can be made to a certain size, the column-shaped part that forms it can also be thickened. . Therefore, the mold can ensure high durability. This point is also one of the effects of the present invention.

1 is a schematic plan view of an automobile equipped with an internal combustion engine of an embodiment; FIG. It is the perspective view which looked at the intake manifold of embodiment from the front downward direction. It is the perspective view which looked at the middle piece from the front. It is the perspective view which looked at the middle piece from the back. It is the perspective view which looked at the middle piece from the front. It is the perspective view which looked at the front piece from the back. It is a front view of a middle piece. Fig. 10 is a rear view of the front piece; FIG. 4 is a diagram comparing a front view of the middle piece and a rear view of the front piece;

(1) Outline of Layout Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic representation of an automobile. In the following description, terms such as front, rear, left, and right are used to specify directions, and these directions are based on the orientation of the driver M. As shown in FIG. Therefore, the forward direction of the automobile is the front, the vehicle width is the left-right direction, and the automobile of this embodiment is a right-hand drive vehicle in which the driver's seat and the steering wheel 1 are on the right side. Since the front view is in the direction facing the driver M, the left and right in the front view and the left and right as seen from the driver M are opposite . Directions are indicated in each figure.

An engine room 2 is formed in the front part of the vehicle body, and an engine body 3 constituting an internal combustion engine (an internal combustion engine) is arranged in the engine room 2 with a crank axis 4 extending horizontally. Although the engine body 3 is shown in a simplified manner, it includes a cylinder block, a cylinder head fixed to the upper surface thereof, a head cover 5 fixed to the upper surface of the cylinder head, an oil pan fixed to the lower surface of the cylinder block, and the cylinder block. It consists of a cylinder head and a front cover that overlaps one side of the oil pan.

Needless to say, the front cover covers the timing chain. The head cover 5 also overlaps the upper surface of the front cover. A transmission case 6 is fixed to the left side surfaces of the cylinder block and the oil pan.

The front surface of the cylinder head is an exhaust side surface, and an exhaust system member 7 such as a catalytic converter is connected to the exhaust side surface, while the rear surface is an intake side surface. is fixed. Therefore, the internal combustion engine of the present embodiment is of the horizontal type with front exhaust and rear intake.

A brake pedal 9 is arranged in the lower back part of the driver's seat, and the stepping force of the brake pedal 9 is amplified by a brake booster 10 arranged in the right rear part of the engine room 2 and transmitted to a master cylinder 11. - 特許庁The brake booster 10 is operated by intake negative pressure, and therefore the brake booster 10 and the intake manifold 8 are connected by a negative pressure tube 12 .

1 , the intake manifold 8 includes a front piece 13 overlapping the cylinder head (engine body 3) directly or via a spacer member, and a middle piece 14 overlapping the front piece 13 from behind. and a rear piece 15 overlapping the middle piece 14 from behind, and the negative pressure tube 12 is connected to the right end of the middle piece 14 . At the left end of the middle piece 14, an air intake inlet 16 opens substantially upward.

Needless to say, the front piece 13, the middle piece 14, and the rear piece 15 are examples of the resin members described in the claims, and are integrally joined by welding such as ultrasonic welding or high-frequency welding. . In addition, in the automobile of this embodiment, the engine room 2 is located on the passenger compartment side. Reference numeral 17 in FIG. 1 denotes a radiator.

(2). Basic Structure of Intake Manifold Hereinafter, a specific structure of the intake manifold 8 will be described with reference to FIG. 2 and subsequent drawings.

FIG. 2 is a view of the intake manifold 8 viewed from the front, with the front piece 13 appearing in front. 3 is a view from the same direction as FIG. 2 with the front piece 13 removed, so that the front surface of the middle piece 14 is exposed. As can be understood from the comparison of FIGS. 2 and 3, the middle piece 14 is formed with a recess that opens forward, and this recess serves as a surge tank 20 . More precisely, a surge tank 20 is formed by the middle piece 14 and the front piece 13 by covering the recess of the middle piece 14 with the front piece 13 .

As shown in FIG. 2, the upper portion of the front piece 13 is formed with a flange 21 overlapping the intake side surface (rear surface) of the cylinder head. . Two sets of intake ports are opened in the cylinder head corresponding to the intake outlet holes 22 . The flange 21 is formed with bolt insertion holes 21a for fixing the flange 21 to the cylinder head.

The internal combustion engine of this embodiment has three cylinders, and the front piece 13 is formed with three arc-shaped branch passages 23 bulging forward when viewed from the side. As shown in FIG. 6, the upper part of the branch passage 23 is open to the surge tank 20, and the lower half or more is a hollow passage (a rotary slide type is used for the hollow passage). formed by

As shown in FIGS. 3 and 4, the lower end of the middle piece 14 is formed with three lower communication ports 24 that form branch passages 23 and are opened forward and backward. , three upper communication ports 25, which also form branch passages, are formed to open forward and backward.

As shown in FIG. 4, an intake passage groove 26 communicating with upper and lower communication ports 24 and 25 is formed in the rear surface of the middle piece 14 so as to surround the surge tank 20. is surrounded by a rear piece 15 (see FIG. 1) to form a branch passage. Although the details of the rear piece 15 are not shown in the drawings , the rear piece 15 also has three grooves corresponding to the intake passage grooves 26 .

The intake manifold 8 as a whole has a cylindrical shape elongated in the direction of the crank axis 4, and the branch passage 23 encircles the surge tank 20 for nearly one circumference. It can be said that the intake outlet hole 22 formed in the flange 21 of the front piece 13 also constitutes a branch pipe. It corresponds to the formed intake port.

As clearly shown in FIG. 4, the left end of the middle piece 14 is formed with a throttle body mounting seat 27 protruding leftward from the group of branch pipes. is open. Needless to say, a throttle body containing a throttle valve is fixed to the throttle body mounting seat 27 with bolts. Therefore, the throttle body mounting seat 27 is formed with a bolt insertion hole 28 (or a tapped hole).

As can be understood from FIG. 3, the intake air is ejected downward from the intake inlet 16, flows to the right side inside the surge tank 20, and splits into the branch passage 23 formed in the front piece 13. Around the communication port 24 , the direction is turned upward and goes toward the upper communication port 25 .

(3). Pre-chamber As shown in FIGS. 3, 5 and 7, a pre-chamber 29 is formed at the right end of the middle piece 14 and opens forward, and the interior of the pre-chamber 29 opens to the right. The tubular negative pressure outlet 30 is communicated. The negative pressure outlet 30 protrudes rightward in the left-right direction (in the direction of the crank axis 4), and is connected to the negative pressure tube 12 connected to the brake booster 10. As shown in FIG.

As indicated by an arrow 31 in FIG. 5, the intake air flowing into the surge tank 20 from the throttle body mounting seat 27 flows from left to right inside the surge tank 20 and branches to the branch passages 23. Since the port 29 is open forward, the intake air flowing from left to right does not directly flow into the pre-chamber 29. Moisture (water droplets) on the flow of intake air does not enter directly into the negative pressure outlet 30 .

Therefore, entry of moisture into the negative pressure outlet 30 and the negative pressure tube 12 can be prevented or significantly suppressed. As a result, even when the vehicle is operated in a low-temperature environment, the frozen moisture does not interfere with the intake of the negative pressure to the brake booster 10, and the safety of the vehicle can be ensured. The pre-chamber 29 is open substantially in the front-rear direction, and since this direction is the direction in which the molds (cavity and core) move relative to each other during molding, the pre-chamber 29 is formed in a state in which it can be easily demolded. can.

The auxiliary chamber 29 has a right side wall (one side wall) 32 of the middle piece 14 formed with a bulging portion 32a that bulges rightward, and an internal partition wall 33 that surrounds the bulging portion 32a from the inside. It is formed into a pocket shape by The internal partition wall 33 is formed by an upper inclined portion 33a and a lower inclined portion 33b that are bent in a doglegged shape when viewed from the front. It bulges inward. Therefore, the sub-chamber 29 is roughly pentagonal. A connecting portion between the upper inclined portion 33a and the lower inclined portion 33b is formed with a rib 34 for applying an ejector pin when removing the mold.

When the middle piece 14 is manufactured by injection molding using a mold, the portion of the mold (core) that molds the pre-chamber 29 is a columnar protrusion, and the pre-chamber 29 has a certain size. Therefore, the protrusion of the mold also has a sturdy structure. Therefore, there is no possibility that a weak portion is formed in the mold due to the molding of the pre-chamber 29, and the durability of the mold can be improved. It is also possible to form a cooling water passage in the protrusion.

A forward opening groove 36a forming a PCV introduction path 36 is formed in the upper portion of the front piece 13 of the middle piece 14, and overlaps the forward opening groove 36a of the middle piece 14 as shown in FIGS. A rearward opening groove 36 b is formed, and the upper end of the rearward opening groove 36 b communicates with a PCV inlet 37 formed in the flange 21 .

As shown in FIG. 2, the PCV inlet 37 opens in front of the flange 21 . When the flange 21 is fixed over the intake side surface of the cylinder head, a PCV passage through which the PCV inlet 37 flows is formed in the cylinder head, and the PCV inlet 37 is connected to the PCV passage. On the other hand, when the flange 21 is fixed to the cylinder head via a spacer, a joint hole is formed in the spacer and the PCV tube is connected to the inlet port of the joint hole.

For example, the right side wall 38 of the front piece 13 also has a bulging portion 38a that overlaps the bulging portion 32a of the middle piece 14, as can be clearly understood from the comparative view of FIG. Further, the PCV introduction path 36 formed by the forward opening groove 36a and the rearward opening groove 36b is positioned above the internal partition wall 33 that constitutes the auxiliary chamber 29 and is opened downward, thereby constituting the auxiliary chamber 29. The internal partition wall 33 bulges (protrudes) in a direction crossing the flow of the blow-by gas. Therefore, the blow-by gas and water droplets ejected substantially downward from the PCV introduction passage 36 are guided by the upper inclined portion 33a of the internal partition wall 33, guided into the surge tank 20, and do not enter the negative pressure outlet.

Further, as shown in FIGS. 6, 8 and 9, the front piece 13 is provided with a rib plate 39 which enters the interior of the sub-chamber 29 to divide the sub-chamber 29 into right and left sides and protrudes rearward. There is a certain amount of space between the pre-chamber 29 and the front piece 13 for taking in the intake air. Since the inflow into 29 is greatly suppressed, it is possible to prevent moisture from flowing into the auxiliary chamber 29 along with the intake air.

Also, even if water droplets ride on the intake air and scatter toward the pre-chamber 29, the water droplets collide with the rib plate 39 and atomize. Since the water is returned, water droplets can be prevented from entering the negative pressure outlet 30 .

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways.

The present invention can be embodied in an intake manifold for an automotive internal combustion engine.

1 Handle 2 Engine Room 3 Engine Body 4 Crank Axis 5 Head Cover 8 Intake Manifold 9 Brake Pedal 10 Brake Booster 12 Negative Pressure Tube 13 Front Piece (the other resin member)
14 Middle piece (one resin member)
15 Rear piece 16 Intake inlet 20 Surge tank 27 Throttle body mounting seat 29 Pre-chamber 30 Negative pressure outlet 32 Right side wall (one side wall) of middle piece 14
32a bulging portion 33 internal partition wall 33a upper inclined surface of the internal partition wall 36 PCV introduction path 38 right side wall of the front piece 38a bulging portion 39 rib plate

Claims (2)

It has a surge tank with an intake inlet formed at one end of both ends facing the crankshaft direction, and a group of branch pipes branched from the surge tank and connected at the tip to the intake port of the cylinder head. , the surge tank is formed of two resin members superimposed and joined in a direction orthogonal to the crank axis,
Further, a negative pressure outlet and a gas inlet are formed at the other end of the surge tank opposite to the intake inlet,
One of the two resin members forming the surge tank is formed with a pre-chamber that opens in a direction in which the resin members are superimposed and communicates with the negative pressure outlet,
The gas inlet is formed to open in a direction crossing the opening direction of the auxiliary chamber ,
Further, a rib plate is formed on the other resin member of the two resin members that constitute the surge tank, and enters into the pre-chamber to partition the pre-chamber into two chambers that are separated in the crank axial direction.
Intake manifold for automotive internal combustion engines. The auxiliary chamber is formed by integrally providing an internal partition surrounding a part of the inner surface of one side wall of the one resin member,
The negative pressure outlet is open to the outside of the one side wall, and the gas inlet is open toward the internal partition wall, while the internal partition wall is exposed to the gas ejected from the gas inlet port. is inflated in the direction opposite to the negative pressure outlet so that the
An intake manifold for an automotive internal combustion engine according to claim 1.

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