JPH0415945Y2 - - 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]

In order to generate a strong swirling flow in the combustion chamber during low-load engine operation, the intake passage is a bulkhead that hangs downward from the upper wall of the intake passage and extends from around the intake valve stem toward the upstream side of the intake passage along the axis of the intake passage. The intake passage is divided into a first passage for swirl flow generation and a second passage for bypass by this partition, and an intake control valve that closes during low engine load operation is provided in the second passage. Internal combustion engines are known (see, for example, Japanese Patent Laid-Open No. 59-46321). In this internal combustion engine, by closing the intake control valve when the engine is operating at low load, most of the intake air is supplied into the combustion chamber from the second passage for generating swirling flow, thereby generating a strong swirling flow. There is.

On the other hand, an internal combustion engine is also known which is equipped with a second intake passage in addition to the above-mentioned intake passage with a partition wall in order to improve charging efficiency during high-speed, high-load operation of the engine. Or in the 1980s
-Refer to Publication No. 108724).

[Problem that the invention attempts to solve]

However, since the internal combustion engine described in the above-mentioned Japanese Patent Application Laid-open No. 59-46321 has only one intake valve, there is a limit even if attempts are made to increase the filling efficiency. On the other hand, in the internal combustion engine described in the above-mentioned Japanese Utility Model Application No. 60-92733 or No. 60-108724, the structure becomes complicated because the second intake passage must be formed separately. Not only
Since the length of the second intake passage is relatively long, the flow resistance is large, and there is a problem in that it is not possible to sufficiently increase the filling efficiency even though the second intake passage is provided.

[Means for solving problems]

According to the present invention, in order to solve the above problems,
A partition is formed in the intake passage that hangs downward from the upper wall surface of the intake passage and extends from around the intake valve stem toward the upstream side of the intake passage along the axis of the intake passage. In an internal combustion engine, the intake passage is divided into two passages: one passage and a second passage for bypass, and the intake passage is provided with an intake control valve that closes during low engine load operation to restrict the inflow of intake air into the second passage. A second intake valve is disposed within a second passage located between the intake control valve and the intake valve.

〔Example〕

Referring to FIGS. 1 and 2, 1 is a cylinder block, 2 is a piston that reciprocates within the cylinder block 1, 3 is a cylinder head, 4 is a combustion chamber, 5 is a first intake valve, and 6 is a first intake valve. A second intake valve having a slightly smaller diameter than the valve 5, 7 an intake port common to the first intake valve 5 and the second intake valve 6, 8 an exhaust valve, 9 an exhaust port, and 10 an intake manifold branch pipe. Show each. A fuel injection valve 11 is attached to the intake manifold branch pipe 10, and fuel is injected from the fuel injection valve 11 into the intake port 7. A partition wall 12 is formed in the intake port 7, hanging downward from the upper wall surface of the intake port 7, and extending from around the intake valve stem 5a toward the upstream direction of the intake port 7 along the axis of the intake port 7. The lower wall surface of the partition wall 12 is spaced apart from the bottom wall surface of the intake port 7, so that an intake air circulation space is formed between the lower wall surface of the partition wall 12 and the bottom wall surface of the intake port 7.
The inside of the intake port 7 is divided by a partition wall 12 into a first passage 13 for generating swirl flow and a second passage 1 for bypass.
It is divided into two parts. Hereinafter, the first passage 13 will be referred to as a helical passage, and the second passage 14 will be referred to as a bypass passage. Helical passage 1 as shown in FIG.
3 becomes gradually narrower toward the first intake valve 5.
On the other hand, the bypass passage 14 consists of a wide passage part occupying the upstream half and a narrow passage part occupying the downstream half, and the second intake valve 6 is arranged at the downstream end of the wide passage part occupying the upstream half. . That is, the second intake valve 6 is disposed at a longitudinally intermediate portion of the bypass passage 14. An intake control valve 15 is arranged at the entrance of the bypass passage 14 . The intake control valve 15 has a butterfly shape and extends from the upper wall surface of the intake port 7 to the lower wall surface. The intake control valve 15 is connected to an actuator 17 via a link mechanism 16,
The intake control valve 15 is fully opened by the actuator 17 when the engine is operating at a high load, and is closed when the engine is operating at a low to medium load. This actuator 17 can thus be formed from a diaphragm device with a diaphragm load chamber connected into the intake manifold branch 10.

As mentioned above, when the engine is operating at a low to medium load, the intake control valve 15 is closed as shown in FIGS. 1 and 2. At this time, most of the intake air flows into the helical passage 13. This intake air is accelerated in the helical passage 13, and then flows into the combustion chamber 4 via the first intake valve 5 while swirling along the curved side wall surface around the first intake valve stem 5a. As a result, a strong swirling flow is generated within the combustion chamber 4.

On the other hand, during high engine load operation, the intake control valve 15 is fully opened as shown by the broken line in FIG. Therefore, at this time, most of the intake air flows into the combustion chamber 4 from the second intake valve 6 and the first intake valve 5 through the bypass passage 14 with small flow resistance, and the remaining intake air flows through the bypass passage 13. The air then flows into the combustion chamber 4 from the first intake valve 5. As shown in FIG. 1, the second intake valve 6 is disposed in the middle of the bypass passage 14, so the distance from the upstream end of the partition wall 12 to the second intake valve 6 is short.
The passage resistance from the inlet portion of No. 4 to the second intake valve 6 is extremely small. In this way, high charging efficiency can be obtained during high engine load operation. Further, the swirling flow flowing in from the helical passage 13 and swirling around the first intake valve stem 5a collides head-on with the intake air flowing from the bypass passage 14 toward the first intake valve 5, and as a result, the swirling flow is further weakened. Filling efficiency is increased.

Another embodiment is shown in FIGS. 3 to 4. In this embodiment, an intake control valve 15 having a width approximately equal to the wide passage portion of the bypass passage 14 is arranged at a distance from the upstream end of the partition wall 12 to the upstream side, and when the intake control valve 15 is closed, the intake control valve 15 bypasses the bypass passage 14. Passage 1
It is eccentrically arranged on the bypass passage 14 side so as to restrict the inflow of intake air into the bypass passage 14 . On the other hand, the fuel injection valve 11 is arranged between the side wall surface of the intake port 7 on the side of the helical passage 13 and the intake control valve 15. This fuel injection valve 11 has a pair of injection holes 18a and 18b,
Fuel is injected toward the helical passage 13 from one nozzle hole 18a, and fuel is injected toward the inside of the bypass passage 14 from the other nozzle hole 18b.

In this embodiment as well, the intake control valve 15 is closed when the engine is operating at low and medium loads. At this time, most of the intake air, which is deflected along one side wall surface of the intake port 7 by the intake control valve 15, flows into the helical passage 13, and thus a strong swirl is created in the combustion chamber 4. A flow is generated. On the other hand, when the engine is operated under high load, the intake control valve 15 is fully opened, so that high filling efficiency can be obtained. Further, in this embodiment, the fuel injected from the fuel injection valve 11 is supplied into the combustion chamber 2 via the first intake valve 5 and the second intake valve 6 without colliding with the intake control valve 15 and the partition wall 12. Therefore, the responsiveness of the engine to the fuel injection action can be improved.

[Effect of idea]

By arranging the second intake valve within the bypass passage from the upstream end of the partition wall to the first intake valve, the length of the passage from the bypass passage inlet to the second intake valve is shortened. As a result, the passage resistance between the bypass passage inlet and the second intake valve can be reduced, so that high filling efficiency can be obtained during high engine load operation when the intake control valve is fully open.

[Brief explanation of the drawing]

Fig. 1 is a plan sectional view of the cylinder head, Fig. 2 is a side sectional view of Fig. 1, Fig. 3 is a plan sectional view of the cylinder head showing another embodiment, and Fig. 4 is a side sectional view of Fig. 3. It is a diagram. 4... Combustion chamber, 5... First intake valve, 6... Second
Intake valve, 7... Intake port, 12... Bulkhead, 14
... Helical passage, 14 ... Bypass passage, 15
...Intake control valve.

Claims (1)

[Scope of utility model registration request] A partition is formed in the intake passage that hangs downward from the upper wall surface of the intake passage and extends from around the intake valve stem toward the upstream side of the intake passage along the axis of the intake passage. In an internal combustion engine, the intake passage is divided into two passages: a first passage and a second passage for bypass, and the intake passage is provided with an intake control valve that closes during low engine load operation to restrict the inflow of intake air into the second passage. . An intake system for an internal combustion engine, wherein a second intake valve is disposed in a second passage located between the intake control valve and the intake valve.