JPH08291714A - Intake passage structure for internal combustion engine - Google Patents

Abstract

PURPOSE: To improve combustion characteristics and prevent blowing-back with a simple structure without deterioration of intake charging efficiency. CONSTITUTION: Intake introduced into an intake passage 16A is supplied to a combustion chamber from an intake port branch part 18 through plural ports 17A, 17B. In such an intake passage structure for an internal combustion engine, the intake passage 16A is bent in respect to the intake ports 17A, 17B immediately before the intake port branch part 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake passage structure for an internal combustion engine.

[0002]

2. Description of the Related Art In an intake multi-valve internal combustion engine, a plurality of independent intake ports for each cylinder are provided in a cylinder head, and one opening of each intake port opens as an intake valve opening in the combustion chamber and the other opening. Is open to the outside of the cylinder head as an intake inlet from the intake passage. Then, the intake air (air mixture) introduced into the intake passage is branched at the intake port branching portion and supplied from each intake port to the combustion chamber.

Generally, in an internal combustion engine, except for restrictions on the space of the vehicle, the intake passage and the intake port are arranged so as not to become an intake resistance to the intake air supplied from the intake passage to the combustion chamber through the intake port. It is set to be straight with each other. Conventionally, in such an intake passage structure, as a method for improving combustion characteristics of an internal combustion engine, a vortex flow (swirl flow around a cylinder center axis,
Alternatively, it is known that a tumble flow around an axis orthogonal to the central axis of the cylinder) is generated to enhance the intake flow to increase the flame propagation speed and accelerate the atomization of the air-fuel mixture.

For example, in Japanese Utility Model Laid-Open No. 1-102435, a swirl control valve is installed in the intake port and the direction of the valve is changed so that the intake port functions as a swirl port or functions as a normal port. In order to improve the engine output and the fuel consumption, the disclosure is made.

Japanese Unexamined Patent Publication (Kokai) No. 5-86875 discloses that a swirl flow is generated in the combustion chamber by changing the cross-sectional shape of the intake port. In addition, JP-A-5-1872
Japanese Patent Publication No. 39 discloses that a tumble flow is generated in the combustion chamber by changing the cross-sectional shape of the intake port.

[0006]

However, the prior art has the following problems. An obstacle for intake is arranged in the intake port, or the shape of the intake port reduces the flow velocity of the intake flow, which increases intake resistance and reduces intake charging efficiency (intake efficiency).

The structure of the intake passage becomes complicated and the cost becomes high.

When the intake valve is opened and the exhaust valve is opened, there is no function of preventing so-called blowback, in which the air-fuel mixture flows back from the combustion chamber to the intake port.

An object of the present invention is to improve combustion characteristics and prevent blowback with a simple structure without lowering intake air charging efficiency.

[0010]

According to the present invention, there is provided an intake passage structure of an internal combustion engine for supplying intake air introduced into an intake passage to a combustion chamber from a plurality of intake ports from an intake port branch portion. It is configured to be bent with respect to the intake port near the port branching portion.

[0011]

In general, the fluid in the pipeline has a property of going straight by an inertial force or a property of keeping the pressure in the pipeline uniform. The property of this fluid is the same in the intake passage of the internal combustion engine. As shown in FIG. 5, when the single cylindrical passage is bent, the passage due to the intake flow having the property of going straight A high pressure portion P is formed in the lower part of the inner bend. The flow of intake air branches left and right due to the nature of the fluid that tries to keep the pressure uniform in the high-pressure portion, and rises upward in the left and right along the wall surface of the passage, and the left and right flows collide with each other (FIG. 5 (B)). As a result, collision loss occurs. At this time, regarding the wall surface resistance of this curved passage, since the wall area per unit length at the passage center line does not change, it does not increase as compared with that in a straight passage. Therefore, it can be understood that most of the loss of the kinetic energy of the intake air in the intake passage curved in a single cylindrical shape is the collision loss. Therefore, it is said that the structure of the intake passage is preferably straight from the intake passage to the intake port in order to prevent the occurrence of the collision loss. Then, in the straight intake passage, the fuel may travel along the wall surface of the intake port and be supplied to the combustion chamber as a liquid film flow (droplet flow), which causes deterioration of combustion characteristics.

In the intake passage structure of the present invention, as shown in FIG. 2, the intake air supplied to the intake passage is bent in the vicinity of the intake port branch portion (FIG. 2 (A),
(B)), while branching left and right at the high pressure portion P formed in the lower part near the intake port branching portion (Fig. 2 (C)), while rising up left and right along the wall surface around the intake port branching portion It moves forward (to the combustion chamber side) due to inertia. However, in the present invention, since the intake port is divided into the left and right intake ports at the intake port branch portion, the intake flows that rise upward to the left and right along the wall surface around the intake port branch portion do not collide with each other. , Enters into each of the intake ports and becomes a spiral motion as it is (Fig. 2 (D)), and it is supplied into the combustion chamber by promoting the atomization and homogenization of the fuel (accelerating atomization), and creating a vortex flow in the combustion chamber. Will be generated. That is, according to the present invention, even when the intake passage is bent, (a) since the collision loss of the intake air is not generated, only the intake resistance which is not much different from the straight intake passage is generated, and the intake charging efficiency is reduced. Never. Moreover, (b) the flow of the air-fuel mixture has a swirling motion in the intake port, which prevents fuel from adhering to the wall of the intake port (the swirling flow scrapes off the wall liquid film), and the air-fuel ratio of the air-fuel mixture Optimization and fuel atomization are further promoted. Further, a vortex flow is generated in the combustion chamber, the degree of turbulence of the air-fuel mixture flow in the combustion chamber is increased, the combustion speed is improved, and the combustion characteristics can be improved (engine output can be improved).

Further, in the intake passage structure of the present invention, when the backflow of the air-fuel mixture from the combustion chamber to the intake port occurs when the intake valve opening and the exhaust valve opening overlap, as shown in FIG.
The backflowing gas flow is diverged at the intake port branching portion to form a high pressure portion P below the intake port branching portion (see FIG. 3).
(A) and (B)), the backflow gas flow rises to the upper left and right along the wall surface around the intake port branch at this high pressure portion and collides (FIGS. 3 (C) and (D)). Kinetic energy is attenuated. As a result, the reverse flow of the gas flow from the combustion chamber is suppressed, so-called blowback is prevented, and engine performance is improved.

[0014]

1 is a schematic diagram showing a first embodiment of the present invention, FIG. 2 is a schematic diagram showing the flow of intake air in the intake passage of FIG. 1,
3 is a schematic diagram showing the flow of backflow gas in the intake passage of FIG. 1, FIG. 4 is a schematic diagram showing a second embodiment of the present invention, FIG. 5 is a schematic diagram showing a comparative example of the present invention, and FIG. FIG. 7 is a diagram showing the intake charge performance in the invention example, FIG. 7 is a diagram showing the engine output performance in the invention example, FIG. 8 is a diagram showing the knocking resistance performance in the invention example, and FIG. 9 is a bending angle of the intake passage. FIG. 10 is a schematic diagram showing the relationship with the intake charge performance, FIG. 10 is a schematic diagram showing a third embodiment of the present invention, FIG. 11 is a schematic diagram showing the flow of intake air in the intake passage of FIG. 10, and FIG. 4 is a schematic view showing the fourth embodiment, FIG. 13 is a schematic view showing the flow of intake air in the intake passage of FIG. 12, FIG. 14 is a schematic view showing the fifth embodiment of the present invention, and FIG. 15 is an intake air in the intake passage of FIG. It is a schematic diagram which shows the flow of.

(First Embodiment) (FIGS. 1 to 3 and 6 to 9) In the internal combustion engine 10, as shown in FIG.
2, the cylinder head 13 has an intake valve 14 and an exhaust valve 1
5 is provided. The air introduced and accumulated in the intake collector can be introduced into the intake passage 16A of the intake manifold 16 from the air funnel formed inside the intake collector. The air taken into the intake manifold 16 forms a mixture with the fuel injected from the injector, and this intake air is passed through the intake port 17 and the combustion chamber 1
2 can be supplied.

At this time, the internal combustion engine 10 has one cylinder 1
1 is a two-valve intake type having two intake valves 14, and the intake air introduced into the intake passage 16A of the intake manifold 16 is supplied to the two intake ports 17 from the intake port branch portion 18.
Supply to the combustion chamber 12 via A and 17B (Fig. 1
(B)). In the internal combustion engine 10, the intake passage 1
6A immediately before the intake port branch section 18 and the intake port 17
Bending at a bending angle α with respect to A and 17B (Fig. 1
(A)).

The operation of this embodiment will be described below. In the intake passage structure of the present embodiment, as shown in FIG. 2, the intake air supplied to the intake passage 16A is bent because the intake passage 16A is bent immediately before the intake port branch portion 18 (see FIG. 2).
(A) and (B), the high pressure portion P formed in the immediately lower portion of the intake port branch portion 18 is branched left and right (see FIG. 2).
(C)) While going up to the left and right along the wall surface around the intake port branching portion 18, it advances forward (to the combustion chamber 12 side) due to inertia. However, in the present invention, in the intake port branch portion 18, the intake ports 17 are the left and right intake ports 17A,
By being divided into 17B, the intake flows that rise upward in the left and right along the wall surface around the intake port branching portion 18 do not collide with each other, and
Each of A and 17B enters into a spiral motion as it is (FIG. 2 (D)), and the atomization and homogenization of fuel is promoted (atomization is promoted) to be supplied into the combustion chamber 12 and then to the combustion chamber 12. It will generate a vortex. That is, according to the present embodiment, even when the intake passage is bent, (a) since the collision loss of the intake air is not generated, only the intake resistance which is not much different from the straight intake passage is generated, and the intake charging efficiency is reduced. There is nothing to do. Moreover, (b) in the intake ports 17A and 17B, since the flow of the air-fuel mixture becomes a swirling motion,
Fuel is prevented from adhering to the wall surfaces of the intake ports 17A and 17B (the swirling flow scrapes off the wall liquid film), and the air-fuel ratio of the air-fuel mixture is optimized and the atomization of the fuel is further promoted. In addition, a vortex flow is generated in the combustion chamber 12, the degree of turbulence of the air-fuel mixture flow in the combustion chamber 12 is increased, and the combustion speed is improved.
Combustion characteristics can be improved (engine output can be improved).

Further, in the intake passage structure of this embodiment, when the intake valve 14 and the exhaust valve 15 are overlapped with each other, a backflow of the air-fuel mixture from the inside of the combustion chamber 12 to the intake ports 17A and 17B occurs. As shown in FIG. 3, the backflow gas flow is branched at the intake port branch portion 18, and a high pressure portion P is formed immediately below the intake port branch portion 18 (FIG. 3A).
(B)), and the backflow gas flow rises upward and leftward along the wall surface around the intake port branching portion 18 at the high pressure portion and collides (FIGS. 3C and 3D), and the kinetic energy of the backflow is generated. Attenuated. As a result, the reverse flow of the gas flow from the combustion chamber 12 is suppressed, so-called blowback is prevented, and engine performance is improved.

FIG. 6 is a diagram showing the intake charge performance in the internal combustion engine 10, in which the horizontal axis represents the valve lift amount L of the intake valve 14 and the vertical axis represents the intake air amount A. The example of the present invention (α = 10 degrees) does not lower the intake charging efficiency as compared with the comparative example (α = 0 degrees).

FIG. 7 is a diagram showing the engine output performance of the internal combustion engine 10, with the horizontal axis representing the engine speed N and the vertical axis representing the horsepower PS and torque T. Example of the present invention (α = 10
The degree of horsepower and torque are improved and the combustion characteristics are improved as compared with the comparative example (α = 0 degree).

FIG. 8 is a diagram showing the anti-knocking performance of the internal combustion engine 10. The horizontal axis represents the engine speed N, and the vertical axis represents the knocking occurrence ignition timing ADV (the higher the ADV, the less the knocking occurs). It is a thing. Example of the present invention (α
= 10 degrees) also improves the knocking resistance as compared with the comparative example (α = 0 degrees).

FIG. 9 is a diagram showing the relationship between the bending angle α of the intake passage 16A and the intake air amount A. Bending angle α is 5
The intake filling efficiency can be improved in the range of up to 30 degrees. However, in the present invention, the bending angle α may be 30 degrees or more as long as the main purpose is not to improve the intake charge efficiency but to improve the combustion characteristics due to the generation of vortex flow.

(Second Embodiment) (FIG. 4) The present invention can be applied to an intake multi-valve internal combustion engine other than the intake two-valve internal combustion engine. For example, FIG. 4 shows one cylinder 1
The present invention is applied to an intake three-valve system in which one intake valve 14 is provided with three intake valves 14. That is, the intake manifold 16
When supplying the intake air introduced into the intake passage 16A to the combustion chamber 12 from the intake port branch portion 18 through the three intake ports 17A to 17C, the intake passage 16A is provided immediately before the intake port branch portion 18 on both side intake ports 17A. , 17B,
Bending at a bending angle α. The intake air supplied to the intake passage 16A forms a high pressure portion P in the lower portion of the intake port branch portion 18 and rises upward in the left and right directions. The intake air flow that rises upward in the left and right directions is split into the intake air ports 17A and 17B on both sides to form a spiral flow, which creates a vortex flow in the combustion chamber 12 and improves combustion characteristics. Further, the intake air flows that have risen upward in the left and right directions from the high pressure portion P below the intake port branching portion 18 do not collide with each other and there is no loss of kinetic energy, so that the intake charging efficiency is not reduced.
The blowback prevention is also the same as in the above embodiment.

(Third Embodiment) (FIGS. 10 and 11) The internal combustion engine 20 of FIG. 10 is the internal combustion engine 10 of the first embodiment.
The difference is that the position where the intake passage 16A is bent at the bending angle α with respect to the intake ports 17A and 17B is set before the intake port branch portion 18.

The intake air supplied to the intake passage 16A forms a high pressure portion P at the lower front side of the intake port branch portion 18 (see FIG. 1).
1 (A) to (C)), while going up the wall surface around the intake port branching portion 18 to the upper left and right, it moves forward (to the combustion chamber 12 side) due to inertia. The intake air flows that rise upward in the left and right directions do not collide with each other, and the intake ports 17 on both sides
Each of A and 17B enters separately and becomes a spiral flow as it is (FIG. 11D), and a vortex flow is generated in the combustion chamber 12. As a result, the combustion characteristics are improved without reducing the intake charge efficiency.

Further, when the intake valve 14 and the exhaust valve 15 are overlapped with each other, the intake port 17A from the inside of the combustion chamber 12
The backflow gas flows flowing into 17B merge at the intake port branch portion 18 to form a high pressure portion in the front lower part of the intake port branch portion 18, and the backflow gas flows on the wall surface around the intake port branch portion 18 at this high pressure portion. The kinetic energy of the backflow is attenuated as it rises to the upper left and right and collides. This prevents blowback.

In the present embodiment, the bending position of the intake passage 16A with respect to the intake port branch portion 18 is set so that the intake air that advances forward while moving up and down the wall surface around the intake port branch portion 18 is around the intake port branch portion 18. Of the intake passage 16 so that the intake port branching portion 18 is located closer to the bent position of the intake passage 16A than to the lower layer position where they collide with each other above
It is necessary to set the bending position of A.

(Fourth Embodiment) (FIGS. 12 and 13) The internal combustion engine 30 of FIG. 12 corresponds to the internal combustion engine 10 of the first embodiment.
Is that the intake passage 16A is bent in an R shape with respect to the intake ports 17A and 17B in the vicinity of the intake port branching portion 18 (bending angle α).

The intake air supplied to the intake passage 16A forms a high pressure portion P below the intake port branch portion 18 (see FIG. 1).
3 (A) to (C)), while going up the wall surface around the intake port branching portion 18 to the upper left and right, it moves forward (to the combustion chamber 12 side) due to inertia. The intake air flows that have risen upward in the left and right directions do not collide with each other, and both side intake ports 17A,
17B, each of which separates and enters into a spiral flow (FIG. 13D), and a vortex flow is generated in the combustion chamber 12. As a result, without reducing the intake charging efficiency,
Improves combustion characteristics.

When the intake valve 14 and the exhaust valve 15 are overlapped with each other, the intake port 17A from the inside of the combustion chamber 12
The backflow gas flows flowing into 17B merge at the intake port branch portion 18 to form a high pressure portion near the intake port branch portion 18, and the backflow gas flows on the wall surface around the intake port branch portion 18 at this high pressure portion. The kinetic energy of the backflow is attenuated as it rises to the upper left and right and collides. This prevents blowback.

(Fifth Embodiment) (FIGS. 14 and 15) The internal combustion engine 40 of FIG. 14 is the internal combustion engine 10 of the first embodiment.
The difference is that the intake passage 16A is bent with respect to the intake ports 17A and 17B immediately after the intake port branching portion 18 (bending angle α).

The intake air supplied to the intake passage 16A enters the intake ports 17A and 17B from the intake port branching portion 18, but the intake ports 17A and 17B are V to the intake passage 16A.
Since they are bent and bent in a timely manner, those intake ports 17
A high pressure portion P is formed in the lower inside of A and 17B (see FIG. 1).
5 (A) to (C)). The high pressure portion tries to go straight due to inertia, but since the intake ports 17A and 17B are branched and bent further ahead, the high pressure portion moves forward while climbing up the wall surface of each intake port 17A and 17B to the upper left or right. As a result, the intake air supplied to the intake passage 16A separates into both side intake ports 17A and 17B and becomes a spiral flow without colliding with each other (FIGS. 15 (D) and (E)), and enters the combustion chamber 12. Generate a vortex. As a result, the combustion characteristics are improved without reducing the intake charge efficiency.

When the intake valve 14 and the exhaust valve 15 are open, the intake ports 17A, 1A, 1
The backflow gas flow of the mixer flowing into 7B forms a high pressure portion at the lower part of each intake port 17A, 17B near the intake port branch portion 18, and the backflow gas flows in each intake port 17A, 17B at this high pressure portion. While going up to the left or right along the wall surface, it advances forward (to the side of the anti-combustion chamber 12) due to inertia, and then collides on the wall surface around the intake port branch portion 18,
The backflow kinetic energy is attenuated. This prevents blowback.

The present invention can be applied not only to the intake multi-valve internal combustion engine but also to the intake single-valve multi-cylinder internal combustion engine. That is, in a multi-cylinder internal combustion engine having a single intake port in each cylinder, the intake air introduced into a single intake passage is burned in each cylinder from the intake port branch section through the intake ports of each of the cylinders. When supplying to the chamber, the intake passage may be bent with respect to the intake port immediately before the intake port branch portion.

In the internal combustion engine to which the present invention is applied, only combustion air is supplied to the combustion chamber from the intake passage of the present invention, and fuel is directly or indirectly supplied to the combustion chamber from a system different from the intake passage. It may be one that does.

[0036]

As described above, according to the present invention, the combustion characteristics can be improved and the blowback can be prevented with a simple structure without lowering the intake charging efficiency.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing the flow of intake air in the intake passage of FIG.

FIG. 3 is a schematic diagram showing a flow of backflow gas in an intake passage.

FIG. 4 is a schematic diagram showing a second embodiment of the present invention.

FIG. 5 is a schematic view showing a comparative example of the present invention.

FIG. 6 is a diagram showing the intake filling performance in the example of the present invention.

FIG. 7 is a diagram showing engine output performance in an example of the present invention.

FIG. 8 is a diagram showing anti-knocking performance in an example of the present invention.

FIG. 9 is a diagram showing a relationship between a bending angle of an intake passage and intake charge performance.

FIG. 10 is a schematic diagram showing a third embodiment of the present invention.

11 is a schematic diagram showing a flow of intake air in the intake passage of FIG.

FIG. 12 is a schematic diagram showing a fourth embodiment of the present invention.

13 is a schematic diagram showing the flow of intake air in the intake passage of FIG.

FIG. 14 is a schematic diagram showing a fifth embodiment of the present invention.

15 is a schematic diagram showing the flow of intake air in the intake passage of FIG.

[Explanation of symbols]

 10, 20, 30, 40 Internal combustion engine 12 Combustion chamber 17, 17A, 17B, 17C Intake port 18 Intake port branch section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumihiko Sato, 2266, Uide, Fujinomiya-shi, Shizuoka Prefecture, Inc., K-S Co., Ltd. (72) Naotake Fujita, 2266, Uide, Fujinomiya-shi, Shizuoka Prefecture, Etc. In K-S

Claims (1)

[Claims] 1. In an intake passage structure of an internal combustion engine for supplying intake air introduced into an intake passage to a combustion chamber from an intake port branch portion through a plurality of intake ports, the intake passage has an intake port near the intake port branch portion. An intake passage structure for an internal combustion engine, characterized in that the intake passage structure is bent.