JPH0415943Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to an intake system for an internal combustion engine.

[Conventional technology]

A common intake passage is provided for the first intake valve and the second intake valve, which are arranged in parallel to each other, in order to ensure high charging efficiency during engine high-speed, high-load operation and to generate a strong swirling flow during engine low-load operation. , the intake passage is separated into a first intake passage and a second intake passage by a separation wall extending in the upstream direction of the intake passage from between the first intake valve and the second intake valve, and extends downward from the upper wall surface of the intake passage. A partition wall that hangs down from around the stem of the first intake valve and extends in the upstream direction of the intake passage along the axis of the first intake passage, beyond the upstream end of the separation wall, to the center of the common intake passage. An internal combustion engine in which an intake control valve that opens during high-load engine operation is arranged between the common intake passage side wall surface on the second intake passage side and the upstream end of the partition, and only the upstream end of the partition extends to the bottom wall of the intake passage. has already been proposed by the present applicant (see Utility Model Application No. 129035/1983). In this internal combustion engine, when the engine is running at low load, the intake control valve is closed to send intake air into one of the first intake passages divided into two by a partition wall to generate a swirling flow, and when the engine is running at high load The intake control valve is fully opened to send intake air into the first intake passage on both sides of the partition wall and into the entire second intake passage to ensure high filling efficiency.

[Problem that the invention attempts to solve]

As mentioned above, in this internal combustion engine, the upstream end of the partition wall extends to the bottom wall surface of the intake passage, so when the intake control valve is closed, the intake air along the bottom wall surface of the intake passage flows to the lower wall portion of the upstream end of the partition wall. Since the air is guided by the air and fed into one of the first intake passages, a strong swirling flow can be generated. However, if the upstream end of the partition wall is extended to the bottom wall of the intake passage in this way, a wall will be formed in the center of the intake passage that extends from the upper wall to the lower wall of the intake passage, resulting in increased suction resistance. Thus, there is a problem in that the charging efficiency decreases during high-load engine operation when the intake control valve is fully opened.

[Means for solving problems]

In order to solve the above problems, the present invention includes a partition wall that hangs downward from the upper wall surface of the intake passage and extends from around the stem of the intake valve toward the upstream side of the intake passage along the axis of the intake passage. In an internal combustion engine in which an intake control valve that opens during high engine load operation is arranged between the upstream end of the bulkhead and one side wall surface of the intake passage, the axis of the intake passage is located on the bottom wall of the intake passage below the upstream end of the bulkhead. It forms intake air guide ribs extending in the direction.

〔Example〕

Referring to FIGS. 1 to 3, 1 is a combustion chamber;
Reference numeral 2 indicates a first intake valve, 3 indicates a second intake valve, and 4 indicates an intake passage common to the first intake valve 2 and the second intake valve 3, respectively. A separation wall 5 is formed in the intake passage 4 and extends from between the first intake valve 2 and the second intake valve 3 toward the upstream direction of the intake passage 4.
Accordingly, the intake passage 4 is connected to the first intake passage 6 and the second intake passage 4.
It is separated into an intake passage 7. As shown in FIG. 2, the upstream end 5a of the separation wall 5 extends from the upper wall surface of the intake passage 4 to the lower wall surface. On the other hand, the first intake passage 6
A partition wall 8 that hangs downward from the upper wall surface of the first intake passage 6 is formed therein. This partition wall 8 extends from around the stem 2a of the first intake valve 2 along the axis of the first intake passage 6, beyond the upstream end 5a of the separation wall 5, to the center of the intake passage 4 in the upstream direction of the intake passage 4. . The lower wall surface 9 of the partition wall 8 is arranged at a distance from the bottom wall surface of the intake passage 4, so that a circulation space for intake air is formed between the lower wall surface 9 of the partition wall 8 and the bottom wall surface of the intake passage 4. . The first intake passage 6 is divided into two passages by the partition wall 8, with a helical passage 6a formed on the side opposite to the separation wall 5, and a bypass passage 6b formed on the side of the separation wall 5, respectively. An intake control valve 10 in the form of a butterfly valve is disposed between the intake passage side wall surface 4a on the second intake passage 7 side and the upstream end of the partition wall 8. This intake control valve 10 is connected to an actuator 12 via a link mechanism 11, and is fully opened by the actuator 12 as shown by the solid line when the engine is operating at a high load, and fully closed as shown by the broken line when the engine is operating at a low to medium load. It will be done. This actuator 12 can therefore be formed from a diaphragm device in which a diaphragm negative pressure chamber is connected into the intake passage 4 . As shown in FIG. 2, a fuel injection valve 13 is arranged on the upper wall surface of the intake passage 4 upstream of the partition wall 8.

On the other hand, as shown in FIGS. 1 to 3, an intake air guide rib 14 is formed on the bottom wall surface of the intake passage 4 below the upstream end of the partition wall 8. As shown in FIGS. The rib 14 extends substantially in the axial direction of the first intake passage 6 from slightly upstream to downstream of the partition wall 8, and the downstream end of the rib 14 is located upstream of the upstream end 5a of the partition wall 5. . Further, as shown in FIGS. 2 and 3, the height of the rib 14 is low, so that the rib 14 has a low height.
4 and the lower wall surface 9 of the partition wall 8, an intake air circulation space is formed.

When the engine is operating at a low to medium load, the intake control valve 10 is closed as described above. At this time, the intake air flow flowing along the bottom wall surface of the intake passage 4 is caused by the rib 14.
The air flows into the helical passage 6a as shown by arrow K, and then turns along the curved side wall surface of the first intake passage 6a around the intake valve stem 2a. On the other hand, the intake air flowing through the intermediate height position and upper position of the intake passage 4 is guided by the partition wall 8 into the helical passage 6a as shown by arrow K, and then into the first intake passage 6a around the intake valve stem 2a. Turns along the curved side wall. In this way, when the engine is operating at low to medium load, most of the intake air flows into the helical passage 6a, and then this intake air flows into the helical passage 6a while rotating along the curved side wall surface of the first intake passage 6a around the intake valve stem 2a. 1 combustion chamber 1 through intake valve 2
As the fuel flows into the combustion chamber 1, a strong swirling flow is generated within the combustion chamber 1. If the rib 14 were not provided, the intake air flowing along the bottom wall surface of the intake passage 4 would pass below the partition wall 8 as shown by arrow L and flow into the bypass passage 6b. This intake air collides head-on with the swirling intake airflow that swirls along the curved side wall surface of the first intake passage 6, and as a result, the swirling force of the swirling intake airflow is weakened, creating a strong swirling flow inside the combustion chamber 1. difficult to generate. In this way, the flow path of the intake air flowing along the bottom wall surface of the intake passage 4 has a great influence on the strength of the swirling flow, and therefore, in the present invention, the rib 14 is used to make the flow path of the intake air the strongest. The aim is to direct the flow in a direction that can generate a swirling flow.

On the other hand, when the engine is operated under high load, the intake control valve 10 is fully opened as described above, so that the intake air also flows into the combustion chamber 1 through the second intake passage 7, which has low flow resistance, and as a result, the charging efficiency is increased. . At this time, intake air also flows in from the bypass passage 6b. This intake air enters from the helical passage 6a and collides head-on with the swirling intake air, so that the swirling flow is weakened, and thus the flow path resistance to the intake air flow flowing through the first intake passage 6 is reduced. As a result, the filling efficiency is further improved. In addition, as shown in FIGS. 2 and 3, the rib 1
4 and the lower wall surface of the partition wall 8, the flow resistance of the intake passage 4 is reduced, thus achieving high filling efficiency during high engine load operation when the intake control valve 10 is fully opened. Obtainable.

Another embodiment is shown in FIGS. 4 and 5. Fourth
5 and 5, 20 is a combustion chamber, 2
Reference numeral 1 indicates an intake valve, and reference numeral 22 indicates an intake passage. A partition wall 23 is formed within the intake passage 22 and hangs downward from the upper wall surface of the intake passage 22. This partition 23 extends from around the stem 21a of the intake valve 21 along the axis of the intake passage 22 toward the upstream direction of the intake passage 22, and the lower wall surface 24 of the partition wall 23 is spaced apart from the bottom wall surface of the intake passage 22. It is located. The intake passage 22 is divided into a helical passage 22a and a bypass passage 22b by a partition wall 23, and an intake control valve 25 that opens during high-load operation is disposed at the entrance of the bypass passage 22b. An intake air guide rib 26 extending in the axial direction of the intake passage 4 is formed on the bottom wall surface of the intake passage 22 below the upstream end of the partition wall 23.
A circulation space for intake air is formed between the rib 26 and the lower wall surface 24 of the partition wall 23. Also in this embodiment, when the engine is operated at low to medium load with the intake control valve 25 closed, the intake air flowing along the bottom wall surface of the intake passage 22 is guided into the helical passage 22a by the rib 26, and is thus A swirling flow can be generated. On the other hand, since an intake air circulation space is formed between the rib 26 and the lower wall surface 24 of the partition wall 23, high filling efficiency can be obtained during high engine load operation when the intake control valve 25 is fully opened.

[Effect of idea]

By forming intake air guide ribs on the bottom wall of the intake passage below the upstream end of the partition, a strong swirling flow can be generated, and a circulation space for intake air is formed between the intake air guide ribs and the bottom wall of the partition. This makes it possible to increase the charging efficiency during high engine load operation.

[Brief explanation of drawings]

Fig. 1 is a sectional plan view of the intake passage, Fig. 2 is a side sectional view of the intake passage, Fig. 3 is a sectional view taken along the - line in Fig. 1, and Fig. 4 is an intake passage showing another embodiment. A sectional plan view of the passageway, FIG. 5 is a sectional view taken along the - line in FIG. 4. 2...First intake valve, 3...Second intake valve, 4,2
2... Intake passage, 5... Separation wall, 6... First intake passage, 7... Second intake passage, 8, 23... Partition wall,
10, 25... Intake control valve, 13... Fuel injection valve, 14, 26... Rib.

Claims (1)

[Scope of utility model registration request] A partition is formed in the intake passage that hangs downward from the upper wall of the intake passage and extends from around the stem of the intake valve toward the upstream side of the intake passage along the axis of the intake passage, and the valve opens during high engine load operation. An internal combustion engine in which a control valve is disposed between an upstream end of a partition wall and one side wall surface of an intake passage, wherein an intake air guide rib extending in the axial direction of the intake passage is formed on a bottom wall surface of the intake passage below the upstream end of the partition wall. intake device.