JP3482107B2 - Intake device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine in which a swirl is formed in a combustion chamber, and more particularly to an intake system in which an intake port has directivity.

[0002]

2. Description of the Related Art In an internal combustion engine, if a swirl flow of intake air, that is, a swirl is formed in a combustion chamber,
It is known that combustibility can be improved by promoting fuel mixing and flame propagation.
Therefore, various means for forming the swirl have been considered. As one of such means, the portion of the intake port adjacent to the combustion chamber is curved toward the outer peripheral side of the combustion chamber, and the intake air flowing into the combustion chamber from the intake port is directed in a direction eccentric from the center of the combustion chamber. There is such a method (see, for example, Japanese Patent Publication No. 63-26259).

According to the intake system for an internal combustion engine having such an intake port, the intake air that has flowed into the combustion chamber from the intake port is guided by the outer peripheral surface of the combustion chamber and swirls, so that the combustion chamber is rotated. A swirl is formed on. That is, the intake port becomes a swirl intake port.

[0004]

However, the conventional intake port for swirl generation has a purpose only to give directivity to the intake air flowing into the combustion chamber as described above, and to generate the swirl more strongly. No consideration was given to the shape of the port for the purpose.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain an intake device for an internal combustion engine having an intake port capable of generating a stronger swirl. .

[0006]

In order to achieve this object, the present invention is provided with a throttle portion in the intake port. That is, the intake device for an internal combustion engine according to the present invention has a sidewall surface on the intake direction side of the swirl generation intake port that directs the intake air flowing into the combustion chamber.
The intake valve that opens and closes the intake port is narrowed down to a position where it comes into contact with the counterbore for press-fitting, and the side wall surface adjacent to the combustion chamber is an inclined surface that is inclined in the intake direction. Is characterized by.

With this structure, the intake air flowing through the swirl generating intake port is throttled by the throttle of the intake port, so that the flow velocity thereof becomes large. Moreover, since the portion of the intake port adjacent to the combustion chamber is inclined toward the outer peripheral side of the combustion chamber,
The intake air flowing from the intake port into the combustion chamber is directed in a direction eccentric to the center of the combustion chamber. As a result, a strong swirl is formed in the combustion chamber.

The internal combustion engine has an intake two-port internal combustion engine having a first intake port having a first intake valve that is always operated and a second intake port having a second intake valve that is inactive when the load is low. It can be an institution. In that case, the first intake port is set as the swirl generation intake port. Then, a communication passage directed to the valve center of the first intake valve is formed in the partition wall between the first and second intake ports. By doing so, at the time of low load when the second intake valve is deactivated, the intake air flowing through the second intake port also joins the intake air flowing through the first intake port and flows into the combustion chamber, so a stronger swirl is achieved. Will be formed. Further, the communication passage between the first and second intake ports reduces the increase in intake resistance due to the restriction of the first intake port, so that the output can be prevented from lowering.

In this case, it is desirable that the portion of the narrowed side wall surface of the first intake port adjacent to the combustion chamber be formed substantially parallel to the directing direction of the communication passage between the first and second intake ports. Further, the side wall surface portion may be arranged substantially on the same plane as the upstream end surface of the partition wall facing the communication passage between the first and second intake ports. By doing so, the directivity of the intake air flowing into the combustion chamber becomes clearer, and the swirl generated can be further strengthened. In addition, a portion of the first intake port or the swirl-producing intake port adjacent to the combustion chamber is a downstream side,
That is, it is desirable to form the funnel shape so that the passage diameter increases toward the combustion chamber side. By doing so, an increase in suction resistance due to the throttle of the suction port is reduced, and a decrease in output is prevented.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an intake system for an internal combustion engine according to the present invention. FIG. 1 is a plan sectional view of an intake port provided in a cylinder head of the internal combustion engine, and FIG. 2 is a vertical sectional view of the internal combustion engine. .

As is apparent from these figures, this internal combustion engine is an intake 2-port / exhaust 2-port internal combustion engine, and has a roof type combustion chamber 1. That is, the combustion chamber 1 includes a bottom surface of a cylinder head 3 assembled on the cylinder block 2, an inner surface of a cylinder bore 4 provided in the cylinder block 2, and a piston 5 slidably fitted in the cylinder bore 4. A cylinder head 3 which is formed between the top surface and the top surface of the combustion chamber 1
At a position facing the cylinder bore 4 on the bottom surface of the roof, a pair of roof surfaces 3a, 3b inclined in the left-right direction, respectively.
Are formed. The first intake port 61 and the second intake port 62 are arranged in parallel on one roof surface 3a, and the pair of exhaust ports 71, 72 are arranged in parallel on the other roof surface 3b.

The first and second intake ports 61 and 62 are
The first and second intake valves 81 and 82 are opened and closed, respectively. Those valves 81, 82
Valve shafts 81a and 82a extend in parallel to each other in a direction orthogonal to the axis of the cam shaft of a valve mechanism (not shown), and are slidable by valve guides 91 and 92 attached to the cylinder head 3. It is supported. The valve guides 91 and 92 are press-fitted into the spot facings 101 and 102 provided on the cylinder head 3. The spot facings 101 and 102 are provided with valve guides 91 and 92.
This is a flat surface portion that is pre-machined in order to accurately machine the hole for press-fitting. Those first and second intake valves 8
1, 82 are adapted to be driven by a valve mechanism (not shown). In that case, the first intake valve 81
Normally operates like a normal valve, but the second intake valve 82 is made to pause when the load is low. The exhaust ports 71, 72 are similarly supported by the cylinder head 3 and driven by the valve operating mechanism.
It is adapted to be opened and closed by 112.

As shown in FIG. 1, the cylinder head 3 has a first intake port 12 connected to a first intake port 61.
1 and a second intake port 122 connected to the second intake port 62 are provided. Those first and second intake ports 12
The space between 1 and 122 is partitioned by a partition wall 13. Then, the partition wall 13 is provided with the first and second intake ports 12
A communication passage 14 that communicates between the first and the second 122 is provided. The communication passage 14 is directed to the valve center of the first intake valve 81. That is, the upstream end surface 13 a and the downstream end surface 13 b of the partition wall 13 facing the communication passage 14 are both inclined surfaces that are inclined toward the first intake port 61. The inclination angle is smaller on the end surface 13b on the downstream side than the axis of the cam shaft of the valve mechanism, that is, the straight line in the vertical direction in FIG. Therefore, the intake air flowing through the communication passage 14 is
It is designed to be narrowed toward the intake port 61. In this way, when the second intake valve 82 is at rest, the intake air flowing through the second intake port 122 is guided to the first intake port 121 side and flows into the combustion chamber 1 from the first intake port 61.

The second intake port 1 of the first intake port 121
The side wall surface 15 on the side opposite to 22 is narrowed down to a position in contact with the spot facing portion 101 into which the valve guide 91 of the first intake valve 81 is press fitted. That is, the first intake port 121 is narrowed down to the maximum extent possible. The portion of the side wall surface 15 adjacent to the combustion chamber 1, that is, the portion 15a continuous with the first intake port 61, is
It is an inclined surface that inclines toward the outer peripheral side of the combustion chamber 1. The inclination direction of the side wall surface portion 15a is the first and second directions.
It is substantially parallel to the directing direction of the communication passage 14 provided in the partition wall 13 between the intake ports 121, 122. That is, the side wall surface portion 15 a is formed substantially parallel to the upstream end surface 13 a of the partition wall 13 facing the communication passage 14. The distance r between the side wall surface portion 15a and the extended surface of the partition wall end surface 13a is 0 to 15 mm.

Further, the combustion chamber 1 of the first intake port 121
The portion adjacent to is formed in a funnel shape in which the passage diameter increases toward the downstream side, that is, the combustion chamber 1 side.
Such a shape can be obtained by molding the cylinder head 3 as shown in FIG.
As shown in FIG. 5, a conical port cutter p is inserted from the side of the first intake port 61, and the hatched portion a in FIG.

A flat portion 16 which forms a squish zone when the piston 5 reaches the top dead center is provided on the bottom surface of the cylinder head 3 in the upper surface of the peripheral portion of the combustion chamber 1. However, such a flat portion is not provided between the first intake port 61 and the exhaust port 71 facing it.

Next, the operation of the intake system for an internal combustion engine constructed as above will be described. When the internal combustion engine has a high load, both the first and second intake valves 81 and 82 are operated. Therefore, the intake air flows through the first and second intake ports 12
1, 122, and flows into the combustion chamber 1 from both the first and second intake ports 61, 62. Then, a large amount of intake air thus sucked into the combustion chamber 1 produces a high output.

On the other hand, when the internal combustion engine has a low load, the second intake valve 82 is deactivated and only the first intake valve 81 operates. Therefore, the intake air flows into the combustion chamber 1 only from the first intake port 61. However, at that time, the intake air flowing through the second intake port 122 receives the communication passage 14
Through the first intake port 121 side through
Also, the intake air flowing through any of the second intake ports 121 and 122 is sucked into the combustion chamber 1. Then, as described above, the first intake port 121 is narrowed down by forming the outer side wall surface 15 so as to contact the press-fitting counterbore portion 101 of the valve guide 91, and the communication passage 14 also extends downstream. Since it is throttled, the flow velocity of the intake air flowing through the first intake port 121 and the communication passage 14 becomes high. Further, the first intake port 61 is curved toward the outer periphery of the combustion chamber 1 because the portion 15a of the side wall surface 15 adjacent to the combustion chamber 1 is an inclined surface facing outward, and the communication passage 14 Is also directed toward the center of the first intake port, the intake air flowing into the combustion chamber 1 from the first intake port 61 is directed in a direction eccentric from the center of the combustion chamber 1. As a result, a very strong swirl is formed in the combustion chamber 1. That is, in this example, the first
The intake port 121 is a swirl generation intake port.

In this case, the upstream end surface 13a of the partition wall 13 facing the communication passage 14 is the side wall surface 1 of the first intake port 121.
5 is formed parallel to the portion 15a adjacent to the combustion chamber 1, the direction of the intake flow flowing through the communication passage 14 and the direction of the intake flow flowing through the first intake port 61 are substantially parallel to each other. The inspiratory flow will be directed in the same direction and the swirl produced will be stronger. In particular, those partition wall end faces 13
When a and the side wall surface portion 15a are located on the same plane, the intake air flowing through the communication passage 14 and the first intake port 61
The swirl generated becomes even stronger because the directivity direction of the intake air flowing through the air flow direction completely matches. However, if the distance r between the side wall surface portion 15a and the extended surface of the partition wall end surface 13a is less than 0 mm, that is, negative,
The intake flow that flows through the communication passage 14 is further throttled, the intake resistance increases, the flow velocity decreases, and the swirl that is generated weakens. In addition, the interval r is set to 1
If the size exceeds 5 mm, the directivity of the intake flow becomes unclear and the swirl weakens. Therefore, the distance r is set to 0 to 15 mm as described above. In the illustrated example, the interval r is 5 mm.

If the first intake port 121 is narrowed down in this manner, there is a concern that the intake resistance through the port 121 will increase and the output will decrease. However, in the case of this intake device, the intake port 121 Since the communication passage 14 is provided in the immediate vicinity of the first intake port 61, which is the outlet, an increase in suction resistance is prevented. In addition, the fact that the vicinity of the first intake port 61 has a funnel shape also reduces the increase in suction resistance. And a strong swirl is generated, and the combustibility is remarkably improved,
The output rather rises.

In the above embodiment, an example of the intake two-port internal combustion engine in which one intake valve 82 is completely stopped at the time of low load has been described, but the internal combustion engine is the same when the intake valve 82 is at rest. The intake valve 82 may be slightly lifted even when the load is low in order to prevent the accumulation of the fuel in the.
Further, the present invention is not limited to the intake two-port internal combustion engine in which one intake valve 82 is substantially stopped as described above, but is also applied to an internal combustion engine in which both intake valves 81 and 82 are always operated, for example. be able to. In that case, the first and second intake ports 121 and 122 may be formed so as to be oriented in the same direction. Alternatively, the first intake port 121 and the second intake port 122 may be completely independent, and the second intake port 122 may be closed when the load is low. Furthermore, the present invention can be applied to an intake 1-port internal combustion engine having only a swirl intake port.

[0022]

As is apparent from the above description, according to the present invention, the side wall surface of the swirl generating intake port is narrowed to the maximum extent, so that the flow velocity of the intake air flowing through the intake port is increased. You can Further, since the portion of the intake port adjacent to the combustion chamber is inclined, the intake air flowing from the intake port into the combustion chamber can be directed in a direction eccentric from the center of the combustion chamber. Therefore, a strong swirl can be generated in the combustion chamber, and the efficiency of the internal combustion engine can be improved.

[Brief description of drawings]

FIG. 1 shows an example of an internal combustion engine provided with an intake device according to the present invention, and is a plan sectional view of an intake port portion provided in a cylinder head of the internal combustion engine.

FIG. 2 is a longitudinal sectional view of the internal combustion engine taken along the line II-II in FIG.

FIG. 3 is a view for explaining a processing state of a first intake port, which is an intake port for swirl generation of the internal combustion engine, of FIG.
It is sectional drawing which follows the III-III line.

[Explanation of symbols]

1 Combustion chamber 61 1st intake port 62 2nd intake ports 71, 72 Exhaust port 81 1st intake valve 82 2nd intake valve 91, 92 Valve guide 101, 102 Valve guide press fitting counterbore part 111, 112 Exhaust valve 121 1st Intake port (swirl generating intake port) 122 Second intake port 13 Partition wall 13a Upstream end face 1
3b Downstream end face 14 Communication passage 15 First intake port side wall surface 15a Side wall surface adjacent to combustion chamber

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Arito Hayashi, 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Toru Amemiya 1-4-1 Chuo, Wako-shi, Saitama Incorporated in Honda R & D Co., Ltd. (72) Inventor Taro Endo 1-4-1 Chuo, Wako-shi, Saitama In R & D Co., Ltd. (56) Reference JP-A-11-36876 (JP, A) JP-A-7 −97971 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F02B 31/02 F02B 29/00 F02F 1/42

Claims (5)

(57) [Claims] 1. An intake device for an internal combustion engine, comprising: an intake port for swirl generation, which directs intake air supplied into a combustion chamber in a direction eccentric from a center of the combustion chamber; The side wall surface on the directional side of the intake air is narrowed down to a position in contact with the counterbore for press-fitting the valve guide of the intake valve that opens and closes the intake port, and the side wall surface is adjacent to the combustion chamber. Is an inclined surface that is inclined in the directing direction of the intake air. 2. The internal combustion engine has a first intake port having a first intake valve that is constantly operated, and a second intake port having a second intake valve that is substantially stopped when the load is low. An intake two-port internal combustion engine, the first intake port of which is used as the swirl generation intake port, and is directed to a partition wall between the first and second intake ports and to a valve center of the first intake valve. The intake device for an internal combustion engine according to claim 1, wherein a communication passage is formed. 3. The internal combustion engine according to claim 2, wherein a portion of a side wall surface of the first intake port adjacent to the combustion chamber is formed substantially parallel to a directing direction of the communication passage. Intake device. 4. A portion of a side wall surface of the first intake port adjacent to the combustion chamber is arranged substantially flush with an upstream end surface of the partition wall facing the communication passage. The intake system for an internal combustion engine according to claim 3. 5. The portion of the intake port for swirl generation adjacent to the combustion chamber is formed in a funnel shape whose passage diameter increases toward the combustion chamber side. 4. An intake system for an internal combustion engine according to any one of 4 above.