JP2023128913A - intake manifold - Google Patents

Abstract

To provide an intake manifold which is compact and excellent in the uniformity of distributing intake air into branch pipes.SOLUTION: The intake manifold as a joint product of a synthetic resin member includes a longitudinal surge tank 6, and a plurality of branch pipes 7, 8, 9, 10 arranged so as to be wound on the outer periphery of the surge tank 6. At a site between the adjacent branch pipes such as between the second branch pipe 8 and the third branch pipe 9, an intake introduction boss part 17 is arranged to which a throttle valve is fixed. Inside the surge tank 6, an intake guide part 23 is provided for jumping part of intake air to fly far. The intake air can be uniformly distributed into the branch pipes 7, 8, 9, 10 without increasing the total length of the intake distribution unit including a throttle valve. The branch pipes 7, 8, 9, 10 wound on the surge tank 6 actualizes smooth flow of the intake air and good inertia supercharging effects.SELECTED DRAWING: Figure 6

Description

The present invention relates to an intake manifold used in a multi-cylinder engine for a vehicle or the like.

The intake manifold of a multi-cylinder engine is equipped with a surge tank and multiple branch pipes that branch out from the surge tank.A throttle body is fixed to the intake inlet provided in the surge tank, and the intake manifold has a flow rate controlled by a throttle valve. is distributed to each branch pipe via a surge tank.

Looking at the arrangement relationship between the surge tank and branch pipes, the surge tank is configured to be long in the longitudinal direction, which is the cylinder row direction (camshaft direction, crankshaft direction), and each branch pipe has its inlet connected to the surge tank. The output of each branch pipe is connected to one flange by winding the outer periphery of the surge tank while opening into the inside of the surge tank.

In this case, the intake inlet is often opened at the front or rear end of the surge tank, or at the outer peripheral surface of an overhang provided at the front or rear end of the surge tank. Therefore, the intake air flows from one end of the surge tank to the other end and is divided into each branch pipe.

On the other hand, Patent Document 1 discloses a four-cylinder intake manifold made by joining a plurality of parts made of injection molded synthetic resin, in which the intake manifold is divided into an upstream part and an upper half that constitute the lower half of the intake manifold. It is disclosed that two branch pipes are connected to the front and rear parts of the surge tank, and an intake inlet is provided in the surge tank. In Patent Document 1, the surge tank is located at the front and rear intermediate portions of the intake manifold. Therefore, the intake inlet port is also arranged at the front and rear intermediate portions of the intake manifold.

JP 2007-162520 (Patent No. 4792955) Publication

When each branch pipe is wound around the outer periphery of the surge tank, the length of each branch pipe can be made as long as possible while simplifying the flow of intake air. Therefore, there is an advantage that a high inertia supercharging effect can be enjoyed while suppressing pressure loss. Another advantage is that the surge tank can be set to the required capacity.

However, since intake air tends to travel straight, if an intake inlet is provided at one end of the surge tank, a large amount of intake air tends to flow into the branch pipe located at the other end. If the intake air inlet is provided on the outer periphery of the cylinder, there is a tendency for a large amount of intake air to flow into the branch pipes near the intake inlet, and in any case, variations in the amount of intake air in each branch pipe (in each cylinder) are likely to occur. Become.

Additionally, if the intake inlet is opened at one end of the surge tank, the throttle valve (throttle body) will protrude significantly from the front or rear of the surge tank, causing the intake distribution unit consisting of the intake manifold and throttle valve to move forward and backward. There is also the problem that it becomes longer (larger). The same applies when the surge tank is provided with a forward or backward projecting portion.

In recent years, hybrid engines have become popular as a means of driving automobiles. However, because hybrid engines include components such as large motors and power control units (PCUs), they have limited capacity in the engine room (engine compartment). It is necessary to make effective use of the space (compartments), and the front and rear length of the intake distribution unit is required to be as short as possible. If the intake air distribution unit becomes longer in the front-rear direction due to the above-mentioned configuration, the design will be difficult. Therefore, there is a strong demand for the front-to-back length of the intake air distribution unit to be as short as possible.

A 4-cylinder engine has the advantage of less vibration because the inertia of the crankshaft and each piston is well balanced, but compared to a 3-cylinder engine with the same displacement, it has a longer front-to-back length, so the front-to-back length of the intake distribution unit It can be said that there is a particularly high demand for shortening and miniaturization of .

On the other hand, in the intake manifold of Patent Document 1, the intake inlet is arranged in the middle between the front and rear, so that the front-to-back length of the intake distribution unit consisting of the intake manifold and the throttle valve can be set to the minimum length. Furthermore, it is understood that the intake air flowing in from the intake intake port can be divided into two parts, front and rear, and equally distributed to each branch pipe. Therefore, it can be said that it has an excellent uniform distribution function of intake air and is also highly compact.

However, in Patent Document 1, two branch pipes at the front and rear are opened at the front end face and the rear end face of the surge tank, so the front and rear length of the surge tank has to be shortened. There is a concern that it will be difficult to maintain the required capacity. In addition, each branch pipe changes its direction from the front-rear direction and bends around the front-rear longitudinal axis, which increases the flow resistance of intake air, resulting in poor responsiveness and inertia. There is also concern that the effects of the provision of benefits may be diminished.

Furthermore, if two branch pipes are connected to the front end face and rear end face of the surge tank, the connection positions of the two branch pipes will be shifted, and the lengths of the two branch pipes will likely differ. There is also the problem that designing the branch pipes to have equal lengths becomes complicated.

The present invention was made against the background of the current situation, and aims to provide an intake manifold that can simultaneously achieve compactness, equalization of intake air distribution to each branch pipe, and smooth intake air flow. It is something.

The intake manifold of the present invention has a plurality of configurations, which are specified in each claim. Among these, the intake manifold of claim 1 includes:
"It has a surge tank and a plurality of branch pipes arranged side by side in the front-rear direction, which is the cylinder row direction, and each of the branch pipes has an inlet opening inside the surge tank, and the surge tank can be opened from the outside. It is arranged in a coiled manner, and an intake inlet is provided in the surge tank.
This is the basic configuration.

In the above basic configuration,
“The intake inlet is arranged between two adjacent branch pipes on the outer periphery of the surge tank,
an intake guide part that divides the intake air that has flowed in from the intake inlet port back and forth and equalizes the amount of intake air flowing into each of the branch pipes at a portion of the surge tank that is hit by the intake air that has flowed in from the intake inlet port; is being formed.”
It has the following characteristics.

The invention of claim 2 embodies claim 1,
"There are three or more branch pipes, and a plurality of branch pipes are arranged on at least one side of the front and rear sides of the intake guide part, and the intake guide part has a gutter-like shape with raised front and rear sides. It takes the form of
It has the following characteristics. The concave surface (groove surface) of the gutter-shaped intake guide portion can be adopted in various shapes such as an arc shape, a V shape, or a trapezoid having a flat surface and front and rear sloped surfaces.

In claim 2, the gutter-shaped intake guide portion is configured such that the amount of intake air flowing forward and the amount of intake air flowing backward are changed by changing the height of the front end and the rear end or by making the shape of the groove portion symmetrical or asymmetrical. The ratio to the amount of flowing intake air can be made the same or different. This makes it possible to accurately support 3-cylinder engines and 4-cylinder engines.

The intake manifold according to the invention of claim 3 includes:
"It has a surge tank that is long in the front-rear direction, which is the direction of the cylinder row, and a plurality of branch pipes arranged in the front-rear direction, and each of the branch pipes has an inlet opening inside the surge tank, and the surge tank They are arranged one behind the other, wrapping around the tank from the outside.”
In the basic configuration, "an intake inlet is arranged at the front and back midway points on the outer periphery of the surge tank, and the intake air flowing into the surge tank from the intake inlet is directed in the front and rear direction and flows through each of the branch pipes. '
It has the following characteristics.

In each invention of the present application, since the intake inlet to which the throttle valve is attached is arranged between the front end and the rear end of the surge tank, the overall length of the intake manifold does not become long. Therefore, it can be made compact.

In addition, since each branch pipe is designed to wrap around the outer circumference of the surge tank, the intake air that flows into each branch pipe simply flows around the outer circumference of the surge tank, and there is no sudden change in direction. No pressure loss occurs, and the inertial supercharging effect can be improved by lengthening the branch pipe. Moreover, since each branch pipe is wound around the outer periphery of the surge tank in the same manner, it is extremely easy to make each branch pipe equal in length. Therefore, when forming an intake manifold by joining resin molded products, the structure can be simplified and costs can be reduced.

The intake air that flows into the surge tank from the intake inlet changes its direction back and forth inside the surge tank before flowing into each branch pipe, so if the intake air is provided at the front or rear end of the surge tank, In comparison, it has an excellent ability to evenly distribute intake air to each branch pipe. That is, the distribution function of the surge tank can improve the uniformity of distribution of intake air to each branch pipe. Further, since each branch pipe can be made to have the same length and the flow of intake air can be made smooth, inertial supercharging using intake pulsation can be equally achieved in each cylinder. As a result, it can contribute to improved output.

In particular, when the intake guide part is provided as in claim 1, even if a plurality of branch pipes are arranged on one or both of the front and rear sides of the intake inlet, the intake air can be controlled by the rectifying action of the intake guide part. Can be distributed evenly to each branch pipe. As a result, it is possible to improve the uniformity of the air-fuel ratio in each cylinder to ensure stable operation, and it is also possible to improve the function of preventing deterioration of exhaust gas components.

EGR gas and blow-by gas are returned to the intake system, and fuel evaporated in the fuel tank (purge gas) is sent to the intake system, but in the present invention, the intake air to each branch pipe is Excellent in equalizing distribution, by arranging the discharge ports for these auxiliary gases such as EGR gas, blow-by gas, and purge gas near the intake inlet or near the intake guide, the auxiliary gases can be distributed evenly to each branch pipe. It also becomes easier to distribute.

It is also possible to adjust the inflow amount by arranging a rib or the like at the inlet of each branch pipe as the intake guide part, but if the intake guide part is formed in the shape of a gutter as in claim 3, it is possible to adjust the inflow amount from the intake inlet. The intake air heading towards the intake guide part jumps and changes its direction in the front and back direction by the intake guide part, so it prevents a large amount of intake air from flowing into the branch pipes near the intake inlet, and reduces the flow of intake air to each branch pipe. It is possible to ensure uniformity of distribution amount.

Therefore, with a simple structure, the amount of intake air distributed to each branch pipe (to each cylinder) can be made uniform. In particular, it is preferable to form the intake guide portion into a curved concave surface, since this allows smooth direction change of the intake air.

FIG. 2 is an external perspective view of the embodiment. FIG. 2 is a side view of the embodiment. FIG. 3 is a sectional view taken along III-III in FIG. 2; FIG. 3 is a cutaway perspective view of main parts. FIG. 4 is a sectional view taken along line V-V in FIG. 3 (the cut surface is slightly inclined with respect to the cam axis in plan view). FIG. 4 is a cutaway perspective view from which the inner member is omitted when viewed from the VI-VI viewing direction in FIG. 3; FIG. 7 is a diagram schematically displaying another embodiment.

Next, embodiments of the present invention will be described based on the drawings. This embodiment is applied to an intake manifold of a four-cylinder automobile engine. The engine is placed in the engine compartment with its crank axis extending in the vehicle width direction, with the exhaust side facing forward and the intake side facing rearward as the vehicle moves forward. Therefore, the intake manifold of the embodiment overlaps the intake side surface of the cylinder head from the rear facing the forward direction of the automobile.

In the following, words such as "front and rear" and "left and right" are used to specify directions, but as defined in the claims, the front and rear direction is the cylinder row direction (cam axis direction and crank axis direction), and the left and right direction is This is a direction perpendicular to the crank axis and the cylinder bore axis (a direction substantially perpendicular to the intake side of the cylinder head). In the left-right direction, the side closer to the cylinder head 1 is called the inside, and the side farther from the cylinder head 1 is called the outside. A side view is a state seen from the left and right directions, and a front view and a rear view are states seen from the front and rear directions.

Regarding the front and rear, the side where the timing chain is placed is the front, and the side where the transmission case is placed is the back. The cylinder bore axis of the engine may be slightly slanted so that the exhaust side leans forward a little, but since it is basically a vertical engine, the vertical direction is the same as the vertical direction. Each direction is appropriately indicated in each figure.

(1).Basic structure The intake manifold has the shape of a rugby ball or an egg when viewed from the front and back, and roughly has the shape of a slightly distorted square when viewed from the side. As can be understood from FIG. 3, the intake manifold includes an inner member 2 (first piece) located closer to the cylinder head 1, and an outer member 3 (second piece) located farther from the cylinder head 1. and an intermediate member 4 (third piece) sandwiched between the two to form a hollow structure.

The overlapping members 2, 3, and 4 are joined together by vibration welding using high frequency or ultrasonic waves. In FIG. 3, the boundaries of members are indicated by thick lines. For example, as shown in FIGS. 1, 2, and 6, a flange 5 is formed at the joint (welded part) of overlapping members.

As can be understood from FIG. 3, the inner member 2 and the intermediate member 4 have recesses that are open to face each other, and therefore, the inner member 2 and the intermediate member 4 are mainly located inside the intake manifold. A surge tank 6 that is long in the front-rear direction is formed by these. For example, as shown in FIGS. 1 and 3, four branch pipes 7, 8, 9, and 10 are arranged in order from the front so as to wrap around the outer periphery of the surge tank 6. As can be understood from FIG. 3 and FIGS. 5 and 6, the surge tank 6 has a cross-sectional shape close to a rectangular shape, in which the vertical width is slightly larger than the horizontal width (circular, oval, etc. can also be adopted).

In FIG. 6, the upper part of each branch pipe 7, 8, 9, 10 is shown as a cross section formed by the outer member 3 and the intermediate member 4. On the other hand, in FIG. 6, the portions below the branch pipes 7, 8, 9, and 10 shown as cylinders are hatched to represent the inner end face of the intermediate member 4, which is a cross-sectional representation. isn't it.

As shown in FIG. 3, each branch pipe 7, 8, 9, 10 has an inlet (upstream end) 11 connected to the upper part of the surge tank 6 near the cylinder head 1, and winds the surge tank 6 downward. The outlet 12 faces the cylinder head 1 , oriented upwardly from the cylinder head 1 . Therefore, the surge tank 6 is wrapped around approximately one turn. The outlet of each branch pipe 7, 8, 9, 10 is connected to the longitudinal upper flange 13. As shown in FIGS. 1 and 2, the upper flange 13 has a bolt insertion hole 14 for fastening to the cylinder head 1.

Each intake port (not shown) of the cylinder head 1 is comprised of a pair of front and rear ports. Therefore, as shown in FIG. 5, the outlet 12 of each branch pipe 7, 8, 9, 10 is partitioned into the front and back by a partition wall 12a.

As shown in FIGS. 1 and 2, an air intake introduction boss portion 17 with an air intake port 16 opened at a portion of the outer member 3 constituting the surge tank 6 between the second branch pipe 8 and the third branch pipe 9 are integrally formed. The intake air introduction boss portion 17 is connected to the upper part of the surge tank 6, and although it basically faces upward, it is inclined upward and away from the cylinder head 1 when viewed in the front-rear direction (front view or rear view). ing.

Each branch pipe 7, 8, 9, 10 is formed in the inner member 2 from the inlet 11 to the lower end. This structure can be manufactured using a mold with a pivoting core. The region from the lower end to the upper flange 13 is formed by joining the outer member 3 and the intermediate member 4.

The upper end of the intake air introduction boss portion 17 is a receiving seat (flange portion) 17a for fixing a throttle body (not shown), and the receiving seat 17a has three tapped holes 18 for fastening the throttle body. Some places are formed. As shown in FIGS. 3 and 4, a gasket 19 is attached to the top surface of the receiving seat 17a.

By interposing the intake air introduction boss portion 17 between the second branch pipe 8 and the third branch pipe 9, the second branch pipe 8 and the third branch pipe 9 are spaced apart from each other on the left and right except for the outlet 12. is expanding. The widening interval is largest at the location where the intake air introduction boss portion 17 is arranged. Therefore, the second branch pipe 8 and the third branch pipe 9 meander slightly in the front-rear direction.

The longitudinal width of the intake manifold is determined by the pitch of the intake ports in the cylinder head 1, but as shown in FIG. 2, the pitch of each branch pipe 7, 8, 9, 10 is constant at the outlet 12. Therefore, even if the intake introduction boss portion 17 is disposed between the second branch pipe 8 and the third branch pipe 9, the total length of the intake manifold does not become longer. Therefore, the intake manifold has the minimum necessary length from front to back.

As shown in FIGS. 1 to 3, the intake air introduction boss portion 17 is provided with a purge gas introduction port 20. The purge gas introduction port 20 is arranged slightly toward the upper end of the intake air introduction boss portion 17 and protrudes toward the side opposite to the cylinder head 1 . Therefore, the hose can be easily connected (inserted).

As shown in FIGS. 1 to 3, a PCV gas introduction port 21 is provided in a portion of the surge tank 6 below the intake air introduction boss portion 17. The PCV gas introduction port 21 also projects toward the side opposite to the cylinder head 1. As shown in FIG. 1, a pin 22 for positioning the throttle body is provided on the upper surface of the downstream portion of the second branch pipe 8 to protrude upward.

(2).Intake and PCV gas guide structure As can be understood from FIGS. 4 to 6, the inlet 11 of each branch pipe 7, 8, 9, 10 is located on the opposite side of the cylinder head 1 toward the inside of the surge tank 6. It is open outward. Then, the intake air flows into the surge tank 6 in a direction that crosses the surge tank 6 due to the guiding action of the intake air introduction boss portion 17, and then hits the inner surface of the surge tank 6 and changes its direction to flow in the front-rear direction. Then, it turns inward, which is the direction across the surge tank 6, and flows into the inlet 11 of each branch pipe 7, 8, 9, 10.

In this embodiment, an intake guide section 23 that is continuous with the lower end of the intake introduction boss section 17 is provided at the front and rear middle portion of the bottom of the surge tank 6 . As can be understood from FIG. 3, the intake guide portion 23 is formed on the intermediate member 4, and has a gutter-like shape with both front and rear ends raised and a concave surface recessed downward. As shown in FIG. 3, the intake air introduction boss portion 17 and the intake guide portion 23 intersect at an obtuse angle when viewed from the front (rear view), and the intersection angle θ is approximately 120°.

Also, as shown in FIG. 3, a second branch pipe 8 and a third branch pipe 9 are provided on the inner surface of the surge tank 6 on the side opposite to the intake introduction boss part 17 with the intake guide part 23 in between. There is a center back plate 24 located in between. The lower part of the center back plate 24 is a sloped part 24a that becomes lower toward the outside (toward the lower end of the air intake inlet 16).

As can be understood from FIG. 6, the longitudinal width of the intake guide portion 23 is set to be approximately the same as the inner diameter of the intake air introduction port 16. Therefore, most of the intake air flowing in from the intake air introduction boss section 17 heads toward the intake guide section 23, and then collides with the center back plate 24 and is divided back and forth. There is a certain amount of clearance between the intake guide part 23 and the center back plate 24.

As clearly shown in FIG. 6, the intake guide portion 23 is formed by providing an M-shaped guide rib 25 on the bottom of the surge tank 6. That is, the upper plate of the M-shaped guide rib 25 constitutes the intake guide portion 23. Therefore, the foot plates 26 forming the guide ribs 25 are connected to both the front and rear ends of the intake guide part 23, and the intake guide part 23 and the foot plates 26 are connected to (are in contact with) the intake introduction boss part 17. .

Therefore, as shown in FIG. 6, the area surrounded by the guide ribs 25 and the surge tank 6 is a PCV gas distribution passage 27 that opens inward. It is vertically continuous with the PCV gas introduction passage 28 which communicates with the PCV gas introduction passage 28 .

The middle part 23a of the outer end of the intake guide part 23, which is painted black in FIG. The side portions 23b on both sides and the foot plates 26 of the guide ribs 25 form free ends that are not in contact with the inner member 2. Therefore, the PCV gas distribution passage 27 opens outward into the surge tank 6 at its front and rear sides. As a result, as shown by dotted arrows in FIG. 6, the PCV gas is sucked into the intake air flow and distributed equally to each of the branch pipes 7 to 10 due to the venturi action (ejector action) caused by the intake air flow.

As shown in FIGS. 3 and 4, a buffer portion 28a is formed in the PCV gas introduction passage 28 and extends inside the guide rib 25. As shown in FIGS. The buffer portion 28a is formed on the inner member 2 and has approximately the same depth as the center back plate 24. A diversion protrusion 29 for dividing intake air into front and rear parts is formed in about half of the PCV gas introduction passage 28 on the back side. The upper surface of the diversion ridge 29 is inclined so that the height increases toward the back.

(3).Summary In this embodiment, since each branch pipe 7, 8, 9, 10 is wrapped around the surge tank 6, the surge tank 6 can ensure sufficient length to ensure the necessary capacity. In addition, since the branch pipes 7, 8, 9, and 10 are basically long in the circumferential direction, even though they meander somewhat, the flow of intake air is smooth and no pressure loss occurs, and the inertia is high. The length is ensured to realize the effect of supply.

In addition, the surge tank 6 has a wide structure that is long and wide in the front and back to the extent that it spans all cylinders (or all intake ports), and branch pipes 7, 8, 9, and 10 are connected in parallel, and the intake The inlet port 16 (and throttle valve) is located at the front and rear center, but the surge tank 6 The front-back symmetry of the internal structure of the branch pipes 7, 8, 9, and 10 can be ensured, and the arrangement of air intake to the branch pipes 7, 8, 9, and 10 can be improved.

Furthermore, since the intake introduction boss portion 17 to which the throttle valve is attached is located halfway between the front and rear, the intake distribution unit including the intake manifold and the throttle valve only needs to be as long as possible. Therefore, even when there is not enough space in the engine room, such as in a hybrid vehicle, design freedom can be improved.

Further, as already mentioned, the intake air flowing into the intake air introduction boss portion 17 from the intake air introduction port 16 passes through the intake guide portion 23 and hits the center back plate 24, and its direction is changed in the front-back direction due to the collision with the center back plate 24. , and then turns inward and flows into each branch pipe 7, 8, 9, 10.

Since the intake guide portion 23 has a downwardly recessed concave surface, when the intake air changes its direction in the front-rear direction, it receives a jumping action that causes the intake air to move diagonally upward as shown by the arrow in FIG. Therefore, a strong flow of intake air toward the first branch pipe 7 and the fourth branch pipe 10 can be formed. This prevents a large amount of intake air from flowing into the second branch pipe 8 and the third branch pipe 9, and improves the function of evenly distributing the intake air to each branch pipe 7, 8, 9, and 10. As a result, it is possible to equalize the air-fuel ratio of each cylinder and ensure stable operation.

It is preferable to set the intersection angle θ between the intake air introduction boss portion 17 and the intake air guide portion 23 to be an obtuse angle as in the embodiment, since the flow of intake air from the intake air introduction boss portion 17 to the intake air guide portion 23 can be made smooth. . Furthermore, if the inclined portion 24a is formed at the lower part of the center back plate 24, the intake air tends to change its direction in the front-rear direction while swirling, which is preferable because the direction change of the intake air can be made even smoother.

In the embodiment, the intake air introduction boss 17 and the inlet 11 of each branch pipe 7 , 8 , 9 , 10 are located on the left and right sides opposite to each other across the axis of the surge tank 6 . , 8, 9, and 10, the directionality of the flow (inward directionality) imparted by the intake air introduction boss portion 17 remains. Therefore, the flow of intake air can be made smoother, and a high inertial supercharging effect can be achieved.

When the guide ribs 25 are used to form the PCV gas distribution passage 27 as in the embodiment, the PCV gas can be uniformly distributed to the branch pipes 7, 8, 9, and 10. That is, as shown by the dotted line arrow in FIG. Since the inflow of intake air is made uniform, the PCV gas can also be equally distributed to each of the branch pipes 7, 8, 9, and 10. Furthermore, since the guide ribs 25 have both the function of guiding intake air and the function of distributing PCV gas, the structure can be simplified accordingly, which is preferable.

In this embodiment, the longitudinal width of the intake guide part 23 is approximately the same as the longitudinal width of the center back plate 24, but the longitudinal width of the intake guide part 23 (the longitudinal width of the guide rib 25) is the longitudinal width of the center back plate 24. It is also possible to make it smaller than the width, or conversely make it larger. When the front-to-back width of the intake guide part 23 is made larger than the front-to-back width of the center back plate 24, the intake guide part 23 partially overlaps the second branch pipe 8 and the third branch pipe 9 in a side view.

Each member 2, 3, 4 is manufactured using a molding device that uses molds (cavity and core) that move toward and away from each other in the left and right direction in the state shown in FIG. type is added). Since the guide ribs 25 are oriented in the direction of relative movement of the molds, they can be easily manufactured using a molding device with a simple structure. This point is also an advantage of this embodiment.

(4).Other Embodiments FIG. 7 shows another example of the gutter-shaped intake guide portion 23. In the example shown in (A), the intake guide portion 23 is formed in the shape of a gutter having a V-shaped recess. In the example shown in (B), the intake guide portion 23 is formed in the shape of an arcuate gutter, and one foot plate 26 is formed at the front and rear intermediate portions. Therefore, the guide rib 25 is approximately Y-shaped. In this example as well, the intake guide portion 23 can be formed into a V-shape as in (A).

In the example shown in (C), the intake guide portion 23 is formed in a trapezoidal shape with a flat portion, and the foot plates 26 are provided at two bent portions in the front and back. In either example, since the front and rear ends of the intake guide portion 23 are both high, the intake air can be evenly distributed to the branch pipes 7, 8, 9, and 10 due to the jump action of the intake air.

In the example shown in FIG. 7D, the intake guide portion 23 is formed in the shape of a gutter with an arcuate surface, and has different heights at the front and rear. Therefore, more intake air flows toward the lower height side. For example, in the case of an intake manifold for a three-cylinder engine, it would be placed between the first branch pipe 7 and the second branch pipe 8, or between the second branch pipe 8 and the third branch pipe 9. By changing the front and rear heights of the intake guide part 23 as in this example, the amount of intake air to the area where two branch pipes are increased is increased, and the two branches are sent far away by the jumping action. The amount of air taken into the tube can be equalized.

In the example shown in (E), the intake guide portion 23 is formed in a W shape with a peak at the front and rear middle portions. In this example, it is understood that the function of dividing the intake air into front and rear parts is enhanced. The height of the peak in the middle portion may be the same as the height of both the front and rear ends. Note that the example (D) can be combined with other examples.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, in the embodiment, the intake guide portion is formed on a guide rib having a foot plate, but it is also possible to provide it directly on the bottom surface of the surge tank. Further, it is also possible to provide an intake guide portion such as a warp plate at each location of each branch pipe. Furthermore, it is also possible to form a concave groove in a portion of the bottom of the surge tank corresponding to the intake inlet to serve as an intake guide portion. It is also possible to use concave grooves and ribs (or protrusions) together.

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

1 Cylinder head 2 Inner member 3 Outer member 4 Intermediate member 6 Surge tank 7, 8, 9, 10 Branch pipe 13 Upper flange 16 Intake inlet 17 Intake inlet boss portion 17a Seat to which the throttle valve is fixed 21 PCV gas inlet port 23 Intake guide section 24 Center back plate 25 Guide rib 26 Foot plate 27 PCV gas distribution passage

Claims (3)

It has a surge tank and a plurality of branch pipes arranged side by side in the front-rear direction, which is the cylinder row direction, and each of the branch pipes has an inlet opening inside the surge tank and winds the surge tank from the outside. An intake manifold arranged in such a manner that the surge tank is provided with an intake inlet,
The intake inlet port is disposed between two adjacent branch pipes on the outer periphery of the surge tank,
an intake guide part that divides the intake air that has flowed in from the intake inlet port back and forth and equalizes the amount of intake air flowing into each of the branch pipes at a portion of the surge tank that is hit by the intake air that has flowed in from the intake inlet port; is formed,
intake manifold. There are three or more branch pipes, and a plurality of branch pipes are arranged on at least one side of the front and rear sides of the intake guide part, and the intake guide part has a gutter-like structure with raised front and rear sides. takes the form of
An intake manifold according to claim 1. It has a surge tank that is long in the front-rear direction, which is the direction of the cylinder row, and a plurality of branch pipes arranged in the front-rear direction, and each of the branch pipes has an inlet opening into the inside of the surge tank. It is an intake manifold arranged in front and back so as to wrap from the outside,
An intake inlet is disposed at a front and back middle part of the outer periphery of the surge tank, and the intake air that flows into the surge tank from the intake inlet changes its direction in the front and back direction and flows into each of the branch pipes.
intake manifold.

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