JP7601535B2 - Automotive engine intake manifold - Google Patents

Description

This invention relates to an intake manifold that is formed with a negative pressure outlet port for a brake booster in an automobile engine equipped with a brake booster that operates with intake negative pressure.

In automobiles, the force applied to the brake pedal is amplified by a brake booster, and in passenger cars and small and medium-sized trucks, the brake booster often uses the intake negative pressure. Specifically, a negative pressure extraction port for the brake booster is provided in the surge tank of the intake manifold, and the negative pressure extraction port is connected to the brake booster by a hose.

The problem here is that the intake air, blow-by gas, and EGR gas that flow into the surge tank contain moisture, and if this moisture condenses and freezes in the negative pressure outlet port in a low-temperature environment, it can cause a malfunction in which the brake booster does not work.

Therefore, measures have been taken to prevent moisture from entering the negative pressure outlet port. For example, Patent Document 1 discloses that a recessed step is formed on the outside of the surge tank, and the negative pressure outlet port is opened in this step.

In recent years, intake manifolds are often constructed with a hollow structure by joining multiple synthetic resin shell-shaped members, but Patent Documents 2 and 3 disclose that a partition is provided on the inner surface of one of the multiple shell-shaped members that make up the intake manifold, which has a negative pressure extraction port, so as to surround the negative pressure extraction port.

Furthermore, Patent Document 4 discloses a technology in which a raised portion is formed on the inner surface of one shell-shaped member and a negative pressure outlet port is opened on the side of the raised portion, thereby preventing water droplets that have run down the inner surface of the shell-shaped member from entering the negative pressure outlet port.

JP 2020-037918 A JP 2010-084641 A JP 2013-133723 A JP 2007-40142 A

In each of the patent documents, it is said that the negative pressure extraction port is protected by a step or a partition, so that it is possible to prevent moisture from entering the negative pressure extraction port. However, because the negative pressure extraction port opens directly into the inside of the surge tank, it is thought that this does not adequately prevent water droplets contained in the intake air or blow-by gas from entering the negative pressure extraction port.

The present invention was made to improve this current situation.

The intake manifold of the present invention has the following features:
"A surge tank with one intake inlet and one brake booster negative pressure extraction port, and a plurality of intake outlet passages branching from the surge tank,
The surge tank is formed into a hollow structure by joining two shell-shaped members each having an opening facing each other ,
A partition wall is provided at an edge of the surge tank so as to protrude from the two shell-shaped members so as to face each other, thereby forming a semi-closed space separated from a main chamber to which the intake outlet passage is opened via a gap,
The negative pressure outlet port is formed in one of the two overlapping shell-like members so as to open into the semi-closed space .
In this basic configuration,
" With the axial direction of the camshaft being the front-rear direction, the intake inlet opens at one of the front-rear ends of the surge tank, the semi-closed space is formed at the other of the front-rear ends of the surge tank, and the partition that constitutes the semi-closed space faces the intake inlet. "
It has the following characteristics:

In claim 2 , in the same basic configuration as claim 1,
"The two partitions constituting the semi-closed space are arranged in a generally vertical direction, and a recess (water collection area) where water droplets that flow down from the partition or its vicinity can collect is formed at the base or periphery of the lower partition so as to be exposed to the main chamber."
The structure is as follows.

The shape of the recess can be selected in various ways. One example is a depression as in the embodiment, but other shapes such as slit-like grooves, holes, and gutter-like passages surrounded by ribs can also be used. The number and size can be set as desired. In any case, it is preferable that at least a portion of the recess is exposed to the intake air flow. It is sufficient for the recess to have the function of collecting water and dissipating it with the intake air flow, and it is not necessary for water to accumulate.

Intake manifolds equipped with surge tanks have a variety of intake inlet placements, but they can be roughly divided into two types: one in which the intake inlet opens in a direction that intersects with the cam axis, and one in which the intake inlet opens in the direction of the cam axis. In either case, the position of the recess and the opening direction should be set according to the flow of intake air inside the surge tank.

As an example of developing claim 2, claim 3 discloses a preferred example applied to a type in which the intake inlet opens in the camshaft direction. That is, the invention of claim 3 is as follows:
" With the axial direction of the camshaft being the front-rear direction, the intake inlet opens at one end of the front-rear ends of the surge tank, and the semi-closed space is formed at the other end of the front-rear ends of the surge tank,
The intake air flowing into the surge tank from the intake inlet flows toward the other end where the semi-closed space is formed, and is changed in direction at the other end to flow toward each of the intake outlet passages,
Furthermore, a curved portion that bulges toward the main chamber when viewed from the overlapping direction of the two shell-shaped members is formed in the shell-shaped member in which the recess is formed, the portion being exposed to the redirected intake air flow, and the recess is formed in the curved portion.
The structure is as follows.

In the present invention, the negative pressure extraction port opens into the semi-closed space of the surge tank, so even if the intake air, blow-by gas, EGR gas, etc. that flows into the surge tank contain moisture, the partition prevents the moisture from directly entering the negative pressure extraction port. Therefore, it is possible to prevent or significantly suppress the moisture from entering the negative pressure extraction port. As a result, the brake booster can be operated even in low temperature environments, improving safety.

The semi-closed space is formed by protruding partitions from each of the two shell-shaped members that make up the surge tank, so the partitions do not protrude too high, preventing vibrations and noise caused by the formation of the partitions. Rather, both shell-shaped members are reinforced by the partitions, which contributes to increasing the strength of the intake manifold.

In claim 2, even if condensed water adheres to the partition wall or its surrounding area, the condensed water can be collected in the recess and dispersed by the intake air flow. In other words, the Venturi effect (or ejector effect) allows the intake air flow to suck out the water that has accumulated in the recess. This effectively prevents moisture from entering the negative pressure outlet port.

Furthermore, when the configuration of claim 3 is adopted, the recess opens sideways to the intake air flow, so that the suction action due to the Venturi effect (or ejector effect) acts strongly on the recess, and the suction action (suction action) toward the main chamber can be significantly improved. This ensures that water droplets that have accumulated in the recess are sucked out and dispersed inside the surge tank. This improves the reliability of the effect of preventing moisture from entering the negative pressure outlet port.

In this case, the recess is formed in the curved portion, but because the curved portion bulges toward the main chamber of the surge tank, the intake air tends to hit the curved portion hard and change direction, so the intake air tends to skim the recess and flow, and the Venturi effect (or ejector effect) of the recess becomes prominent. As a result, the reliability of preventing moisture from entering the negative pressure extraction port can be improved. Furthermore, moisture that is carried by the intake air and diffuses into the main chamber of the surge tank is atomized and discharged into the combustion chamber (cylinder) via each intake outlet passage and intake port.

In claims 1 and 3 , the partition wall that constitutes the semi- closed space can be used to change the direction of the intake air. In this case, the partition wall is always exposed to the strong flow of intake air, so the generation of condensation water can be prevented or significantly suppressed. This contributes to improving the effect of preventing moisture from entering the negative pressure outlet port. In addition, since the gap opens to the main chamber of the surge tank and is exposed to the flow of intake air, when the brake booster is activated, the air in the semi-closed space can be directly sucked in through the gap. This can be said to improve the responsiveness of the brake booster's operation.

FIG. 2 is a diagram showing the intake manifold of the embodiment as viewed from diagonally above perpendicular to the cam axis. 1 is a view showing the first shell-shaped member positioned on the cylinder head side as viewed obliquely from above. FIG. FIG. 2 is a perspective view of the first shell-shaped member as viewed obliquely from above. FIG. 4 is an enlarged view of a main portion of FIG. 3 . 13 is a perspective view of a main portion of the second shell-shaped member when turned over and viewed from below. FIG. FIG. 2 is a view of the intake manifold as viewed from the intake air inflow direction. 1 is a cutaway perspective view of a main portion of a first shell-shaped member and a second shell-shaped member stacked on top of each other, as viewed from the direction of intake air flow. FIG. 5A and 5B are schematic vertical sectional side views showing the arrangement relationship of two partition walls.

Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to an intake manifold for a three-cylinder engine for an automobile. The engine is mounted in the engine room in a horizontal position with the crankshaft facing in the vehicle width direction. The exhaust side of the engine faces the forward direction of the automobile. Therefore, the engine is a sideways, front-exhaust type. The axis of the cylinder bore is tilted forward at a slight angle toward the forward direction of the automobile.

In the following, the terms front-to-rear, outside-inside, and up-down are used to specify directions; the front-to-rear direction is the cam axis direction (crank axis direction), the outside-inside direction is the approximately horizontal direction perpendicular to the cam axis direction, and the up-down direction is the vertical direction. Regarding front and rear, the side of the engine where the timing chain is located is referred to as the front, and the side where the transmission is located is referred to as the rear. Regarding outside and back, the side closer to the cylinder head is referred to as the back, and the side farthest from the cylinder head is referred to as the outside. Directions are clearly indicated in the diagrams as appropriate.

(1) Basic structure of the intake manifold As shown in Fig. 8, the intake manifold comprises three shell-shaped members, a first shell-shaped member 1, a second shell-shaped member 2, and a third shell-shaped member 3, stacked in a substantially vertical direction, and is formed hollow by joining adjacent shell-shaped members by vibration welding, etc. Therefore, each of the shell-shaped members 1 to 3 is an injection-molded product of synthetic resin.

Figure 2 shows the first shell-shaped member 1 in its entirety. In this embodiment, each shell-shaped member 1 to 3 has approximately the same shape when viewed from diagonally above and to the side (overlapping direction). The parts with parallel diagonal lines (hatching) in Figure 2 are the exposed parts of the first shell-shaped member 1, and therefore most of Figure 1 is taken up by the third shell-shaped member 3. The second shell-shaped member 2 is entirely hidden by the third shell-shaped member 3.

Figure 2 shows only the first shell-shaped member 1, and the overlapping surface 4 with the second shell-shaped member 2 is shown by hatching (therefore, the hatching in Figure 2 does not show a cross section. The same applies to Figures 3 to 5). The second shell-shaped member 2 and the third shell-shaped member 3 also have overlapping surfaces 4 of the same shape as the first shell-shaped member 1, and the overlapping overlapping surfaces 4 are joined by welding such as vibration welding. Therefore, the second shell-shaped member 2 has inner and outer overlapping surfaces 4. In Figures 2 and 3, the overlapping surface 4 is shown as a simple flat surface, but in reality, an annular groove 5 is formed in the overlapping surface 4, as shown in Figures 4 and 5.

As can be seen from FIG. 2, the first shell-shaped member 1 opens on the side opposite (outside) the cylinder head (not shown), and the main recess 7 that constitutes the surge tank 6 is formed to bulge toward the cylinder head. In addition, a mounting seat 9 to which a throttle valve (not shown) is fixed is protruded from the rear wall 8 of the first shell-shaped member 1, and an intake inlet 10 opens into the mounting seat 9. Because the intake inlet 10 opens rearward, the intake air is ejected forward from the intake inlet 10.

The main recess 7 of the first shell-shaped member 1 extends downward and outward beyond the intake inlet 10, and the lower exterior of the first shell-shaped member 1 has first to third lower outer grooves 14 to 16 formed therein to form the inlets of the first to third intake outlet passages 11 to 13.

On the other hand, a longitudinal flange 17 is formed in the upper inner part of the first shell-shaped member 1, located on the opposite side of the main recess 7 from the lower outer grooves 14-16, and overlaps with the intake side of the cylinder head. Three pairs of intake outlet holes, the first to third, 18-20 are opened into the flange 17. The intake outlet holes 18-20 are divided into front and rear by partition walls 18a-20a, respectively, which corresponds to the fact that the intake ports of the cylinder head are separated into pairs.

As shown in FIG. 1, the third shell-shaped member 3 has first to third outer trough-shaped portions 21 to 23 for forming the first to third intake outlet passages 11 to 13, which bulge out on the side opposite the main recess 7.

As shown by dotted lines in FIG. 1 and dashed lines in FIG. 2, the lower part of the second shell-like member 2 is formed with the lower outer grooves 14-16 of the first shell-like member 1 and the first to third lower external communication holes 24-26 that overlap with the lower parts of the outer trough-shaped portions 21-23 of the third shell-like member 3. In addition, although not shown, the upper inner part of the second shell-like member 2 is formed with three upper inner communication holes that overlap with the intake outlet holes 18-19 of the first shell-like member 1 and the upper parts of the outer trough-shaped portions 21-23 of the third shell-like member 3.

Furthermore, between the upper inner communication hole and the lower outer communication holes 24-26 of the second shell-shaped member 2, a first inner gutter-shaped portion 27 (see FIG. 5) that covers the outer gutter-shaped portions 21-23 of the third shell-shaped member 3 from the inside and second and third inner gutter-shaped portions are formed. In FIG. 5, a portion of the first inner gutter-shaped portion 27 is shown as seen from the surge tank 6 side. The second and third inner gutter-shaped portions are not shown.

As can be seen from the dotted arrows in Figure 2, the intake and outlet passages 11 to 13 are located on the front side of the page in Figure 2, and intake air enters the intake and outlet passages 11 to 13 from below and exits from above when viewed from the page.

As shown in Figures 1 and 2, the first shell-shaped member 1 has a plurality of flange-shaped portions 28 for fixing the intake manifold to the cylinder head. In addition, an EGR gas distribution passage 29 is formed on the overlapping surface 4 of the upper part of the first shell-shaped member 1 and the second shell-shaped member 2. The EGR gas distribution passage 29 has a main passage 29a extending from the rear to the front, and two branch passages 29b and 29c branching from the main passage 29a. The end of the main passage 29a is connected to the end of the first intake outlet passage 11, the branch passage 29c located at the rear end is connected to the end of the third intake outlet passage 13, and the branch passage 29b located at the midpoint between the front and rear is connected to the end of the second intake outlet passage 12.

As shown in Figures 2 and 3, a PCV return passage 30 for returning blow-by gas is formed in a longitudinal position on the overlapping surface 4 at the upper back of the first shell-shaped member 1 and the second shell-shaped member 2. The outlet 30a of the PCV passage 30 opens downward toward approximately the middle of the front and rear of the surge tank 6. On the other hand, the inlet 30b of the PCV return passage 30 opens in a portion of the flange 17 of the first shell-shaped member 1 between the first intake outlet hole 18 and the second intake outlet hole 19.

The inlet 30b of the PCV passage 30 is connected to the end of the PCV intermediate passage formed in the cylinder head. Therefore, the PCV intermediate passage formed in the cylinder head opens to the intake side of the cylinder head where the flange 17 overlaps.

1, a cylindrical negative pressure output port 32 for operating the negative pressure brake booster is formed in the front wall of the second shell-shaped member 2, located on the opposite side of the surge tank 6 from the intake inlet 10, so as to protrude forward. The structure related to this negative pressure output port 32 will be described next.

As shown in Figures 2 and 3, the surge tank 6 (and the main recess 7 that constitutes it) is rectangular with the front and rear long sides when viewed from the overlapping direction of the shell-shaped members 1 to 3 (roughly diagonally from the upper side). Therefore, the surge tank 6 has four corners when viewed from the overlapping direction of the shell-shaped members 1 to 3, but as shown in Figures 2 and 3, the negative pressure extraction port 32 is positioned so that it communicates from the front toward the area near the rear front corner 33 of the surge tank 6.

The first shell-shaped member 1 constituting the surge tank 6 has a main step 34a and an auxiliary step 34b that rises diagonally upward and outward from the main step 34a at the rear front corner 33 of the surge tank 6, and a first bulkhead 35 that is roughly U-shaped and protrudes toward the second shell-shaped member 2 is integrally formed with the auxiliary step 34b. Therefore, the surge tank 6 has a first quasi-closed space 36 surrounded by the first bulkhead 35.

The first partition 35 is arranged to surround the outlet of the negative pressure extraction port 32 in a side view. The first partition 35 is also set to be at approximately the same height as the overlapping surface 4 of the first shell-shaped member 1. The first partition 35 does not reach the inner surface 37 of the front wall of the first shell-shaped member 1. Therefore, a gap 38 through which intake air passes is provided between the first partition 35 and the inner surface 37 of the front wall.

The main step 34a is formed in such a way that the rear front corner of the main recess 7 is cut at an angle. Therefore, the intake air that is ejected from the intake inlet 10 and flows forward is guided by the side surface 39 of the main step 34a and changes direction so that it flows downward to the outside, but the side surface 39 of the main step 34a forms a curved portion 39a that bulges generally in the diagonal direction of the main recess 7 in a side view. Therefore, the intake air hits the curved portion 39a strongly.

Then, in the portion of the main step 34a corresponding to the curved portion 39a, a depression (step-shaped depression) 40 that opens diagonally and upwardly to the main depression 7 is formed as an example of a depression described in the claims. The depression 40 reaches the base of the first partition 35. As shown in FIG. 4, the first partition 35 protrudes in an oblique direction that intersects with the vertical line (up-down direction). Therefore, water droplets 41 adhering to the outer surface of the first partition 35 can be collected in the depression 40. As shown in FIG. 4, an upper step 40a is formed in the depression 40. Therefore, the depression 40 has two steps.

As mentioned above, the engine is placed in the engine room in an inclined position with the exhaust side tilted forward, and the intake side of the cylinder head to which the flange 17 of the intake manifold is fixed is inclined so that it approaches the cylinder bore as it goes up. For this reason, Figures 2 and 3 are seen from diagonally above, and Figure 4 is a perspective view seen from a direction close to a side view.

As shown in FIG. 5, a second partition 42 is formed at the rear front corner 33 of the surge tank 6 of the second shell-shaped member 2, thereby forming a second semi-closed space 43. The second partition 42 is connected to two intersecting inner surfaces 44a, 44b of the second shell-shaped member 2. Therefore, the second semi-closed space 43 is open only substantially downward (toward the first semi-closed space 36). The negative pressure output port 32 opens into the second semi-closed space 43, but as shown in FIG. 5, the opening edge of the negative pressure output port 32 is surrounded by a tunnel-shaped enclosure 32a protruding from the inner surface 44a of the side wall.

In this embodiment, the second partition 42 is positioned offset toward the inside of the surge tank 6 from the first partition 35, and as can be seen from Figures 6 and 7, the first partition 35 is covered from the inside by the second partition 42. Therefore, the labyrinth shape of Figure 8 (A) is formed. As also shown in Figure 7, a gap 45 through which intake air passes is formed between the two partitions 35, 42. The first semi-closed space 36 and the second semi-closed space 43 form the semi-closed space described in the claims. In addition, the part of the surge tank 6 excluding the semi-closed spaces 36, 43 is the main chamber. Therefore, it can be said that the main recess 7 is almost the main chamber.

The relationship between the first bulkhead 35 and the second bulkhead 42 can be such that the second bulkhead 42 and the first bulkhead 36 face each other as shown in FIG. 8(B), or the first bulkhead 35 can be closer to the center of the surge tank 6 than the second bulkhead 42 as shown in FIG. 8(C). When the two bulkheads 35, 42 are offset as shown in FIG. 8(A) and (C), in either case, one bulkhead can cover the other bulkhead as shown in (A), or they can be set to the same height as shown in (C).

As mentioned above, each of the shell-shaped members 1 to 3 is an injection molded product, and the partitions 35 and 42 protrude in the direction in which the shell-shaped members 1 and 2 are removed from the mold. Therefore, there are no particular problems in manufacturing.

(3) Summary With the above-described configuration of this embodiment, the main flow of intake air flows from the rear to the front inside the surge tank 6 as shown by the arrow 46 in Fig. 3, but since the main step 34a and the partitions 35, 42 are arranged at the rear front corner 33 in such a manner as to cut the rear front corner 33 diagonally, the intake air is redirected by the main step 34a and the partitions 35, 42 and flows toward the inlets of the intake outlet passages 11-12. Also, a portion of the intake air branches off from the main flow 46 and flows toward the inlets of the second intake outlet passage 12 and the third intake outlet passage 13 as shown by the dotted arrow 47 in Fig. 3.

The negative pressure outlet port 32, which is connected to the brake booster, opens into the semi-closed spaces 36, 43 separated by the partitions 35, 42, so even if moisture is contained in the intake air or blow-by gas, the moisture will not enter the negative pressure outlet port 32 directly.

In this case, the second semi-closed space 43, into which the negative pressure outlet port 32 is directly open, opens only downward and is located above the first semi-closed space 36, so even if moisture-containing intake air enters the first semi-closed space 36, it is difficult for it to enter the second semi-closed space 43. Therefore, moisture can be prevented or significantly suppressed from flying into the negative pressure outlet port 32 and turning into water droplets.

In addition, when operating in a low-temperature environment, for example as shown in FIG. 4, moisture contained in the intake air or blow-by gas may condense on the side of the first partition 36 and grow into water droplets 41. In this case, the water droplets 41 flow down into the recesses 40 and accumulate there.

Then, when the intake air hits the side surface 39 of the step 33 of the first shell-shaped member 1, it changes direction and flows outward, but because the strong flow of intake air passes through the opening edge of the recess 40, a suction force acts on the recess 40 due to the Venturi effect (or ejector effect), which sucks out the accumulated water. The sucked-out water is finely atomized by collisions with the inner surface of the surge tank 6, and is sent to the cylinder via the intake outlet passages 11-13 and the intake port. This prevents water from entering the negative pressure extraction port 32, and prevents the brake booster from operating imperfectly due to the negative pressure extraction port 32 being blocked by freezing.

In particular, a curved portion 39a is formed on the side surface 39 of the main step 34a, and a recess 40 is formed at the curved portion 39a. This allows the intake air to strongly strike the curved portion 39a, increasing the suction effect on the recess 40. This improves the water suction effect, and significantly improves the prevention of water splashing on the negative pressure outlet port 32.

When the brake booster is activated, air is sucked out of the negative pressure outlet port 32 as shown by the arrow in FIG. 8. However, the intake air also passes through the gap 45 between the partitions 35 and 42, providing a high sucking effect on the negative pressure outlet port 32. This results in excellent responsiveness of the brake booster.

As in this embodiment, when the outlet 30a of the PCV return passage 30 is located in the middle between the front and rear of the surge tank 6, the blow-by gas rides on the main intake flow 46 and collides with the side 39 of the main step 34a and the partitions 35, 42, which has the advantage of improving the dispersion of the blow-by gas in the intake air.

As shown by the dashed line in FIG. 4, a slit 34c can be provided in the main step 34a below the first bulkhead 35 as an example of a recess as described in the claims. In this case, water droplets 41 can be collected in the slit 34c and sucked out by the intake air flow. The slit 34c can be formed instead of the depression 40, or the depression 40 and the slit 34c can be provided together.

In addition, in this embodiment, a gap 38 is provided between the first partition 35 and the inner surface 37 of the front wall. Providing the gap 38 in this manner has the advantage that water droplets 41 generated in the first semi-closed space 36 can be dropped through the gap 38. In other words, there is an advantage that the gap 38 can be used as a water droplet suction space.

The above describes an embodiment of the present invention, but the present invention can be embodied in various other ways. For example, the embodiment is a three-part system, but a two-part system is also possible. Also, in the case of the embodiment, it is possible to form a negative pressure extraction port in the first shell-shaped member.

As an example of a recess, for example, a rib parallel to the inner surface 37 of the front wall can be formed in the lower portion of the first bulkhead 35 of the main step 34a shown in FIG. 4, and a gutter-shaped passage between the rib and the inner surface 37 can be used as a recess for collecting water.

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

REFERENCE SIGNS LIST 1 First shell-shaped member 2 Second shell-shaped member 3 Third shell-shaped member 4 Overlapping surface 6 Surge tank 7 Main recess 8 Rear wall 9 Throttle body mounting seat 10 Intake inlet 11-13 Intake outlet passage (branch passage)
21 to 23 Outer gutter-shaped portion constituting intake outlet passage 29 EGR gas distribution passage 30 PCV return passage 32 Negative pressure take-off port 33 Inner front corner portion 34a Main step portion 34b Auxiliary step portion 35 First partition wall 36 First semi-closed space 39 Side surface of step portion 39a Curved portion 40 Depression as an example of a recess 42 Second partition wall 43 Second semi-closed space 45 Gap as claimed

Claims (3)

The system includes a surge tank having one intake inlet and one brake booster negative pressure output port, and a plurality of intake outlet passages branching from the surge tank.
The surge tank is formed into a hollow structure by joining two shell-shaped members each having an opening facing each other ,
A partition wall is provided at an edge of the surge tank so as to protrude from the two shell-shaped members so as to face each other, thereby forming a semi-closed space separated from a main chamber to which the intake outlet passage is opened via a gap,
an intake manifold, the negative pressure outlet port being formed in one of the two overlapping shell-like members so as to open into the semi-closed space,
With the axial direction of the camshaft being the front-rear direction, the intake inlet opens at one end of the front-rear ends of the surge tank, the semi-closed space is formed at the other end of the front-rear ends of the surge tank, and the partition wall constituting the semi-closed space faces the intake inlet side.
An intake manifold for an automobile engine. .
The system includes a surge tank having one intake inlet and one brake booster negative pressure output port, and a plurality of intake outlet passages branching from the surge tank.
The surge tank is formed into a hollow structure by joining two shell-shaped members each having an opening facing each other,
A partition wall is provided at the edge of the surge tank so as to protrude from the two shell-shaped members so as to face each other, thereby forming a semi-closed space separated from a main chamber to which the intake outlet passage is opened via a gap,
an intake manifold, the negative pressure outlet port being formed in one of the two overlapping shell-like members so as to open into the semi-closed space,
The two partition walls constituting the semi-closed space are arranged in a generally vertical direction, and a recess in which water droplets that have flowed down from the partition wall or its vicinity can collect is formed at the base or periphery of the lower partition wall so as to be exposed to the main chamber.
An intake manifold for an automobile engine. the axial direction of a camshaft is a front-rear direction, the intake inlet opens at one end of the front-rear ends of the surge tank, and the semi-closed space is formed at the other end of the front-rear ends of the surge tank,
The intake air flowing into the surge tank from the intake inlet flows toward the other end where the semi-closed space is formed, and is changed in direction at the other end to flow toward each of the intake outlet passages,
Furthermore, a curved portion that bulges toward the main chamber when viewed from the overlapping direction of the two shell-shaped members is formed in a portion of the shell-shaped member in which the recess is formed and that is exposed to the redirected flow of intake air, and the recess is formed in the curved portion.
3. An intake manifold for an automobile engine according to claim 2.

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