JP2001115842A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve combustion stability in lean burn control or the like, by making a turn flow of intake air to collide against injection fuel in a combustion chamber. SOLUTION: A cylinder head 4 is provided with an intake port 6 formed with a first/second branch port 7, 8. Inside the first branch port 7 is partitioned into a peripheral wall side intake passage 7A and a center side intake passage 7B by a partition 14. At lean burn control time, the center side intake passage 7B and the second branch port 8 are blocked by a passage switching valve 15, when intake valves 9, 10 are opened in this condition, intake air is made to flow in a turn flow condition into a combustion chamber 5 from the peripheral wall side intake passage 7A. Here, an injection valve 16 injects fuel F toward inside the combustion chamber 5 from an opening location positioned in a side of a peripheral wall 5A of the combustion chamber 5 of the branch port 8. In this way, a flow of the fuel F is made to collide against a turn flow of intake air, atomization of the fuel and mixing performance are enhanced, and a mixture G can be stably formed in the vicinity of a spark plug 17, so that combustion stability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine suitably used, for example, as an automobile engine, and more particularly to an internal combustion engine which performs lean burn control using a lean air-fuel mixture.

[0002]

2. Description of the Related Art Generally, an internal combustion engine such as an automobile engine has a lean mixture (for example, an air-fuel ratio of 20 to 30) in a combustion chamber when the load on the engine becomes relatively small due to, for example, constant speed running of the vehicle. ) Is performed so as to improve fuel efficiency and purify exhaust gas.

A conventional vehicle engine of this kind includes a cylinder, a cylinder head mounted on the cylinder and defining a combustion chamber corresponding to each cylinder of the engine between the cylinder, and a cylinder head of the cylinder head. An intake port provided on the intake side and formed with first and second branch ports respectively opened to the combustion chamber, a first and second intake valve provided on the cylinder head for opening and closing the respective branch ports, An injection valve for injecting fuel into the combustion chamber via an intake port when each of the intake valves is opened, and a spark plug provided on the cylinder head for burning a mixture of intake air and fuel in the combustion chamber. (For example, Japanese Patent Laid-Open No.
No. 69, etc.).

Here, a swirling flow generating device for generating a swirling flow in the intake air for performing lean burn control is provided on the intake side of the cylinder head. The swirl flow generating device includes, for example, a partition that defines a first branch port of the intake port into a peripheral wall-side passage located on the peripheral wall side of the combustion chamber and a center-side passage located on the center side of the combustion chamber. And a passage switching valve for opening and closing the center side intake passage defined by the partition and the second branch port.

During normal operation of the engine, the passage switching valve is kept open, so that when the intake valve is opened during the intake stroke of each cylinder, the intake air flows through the first and second air intake valves.
Into the combustion chamber through all of the branch ports.

When performing the lean burn control,
The passage switching valve is driven to the valve closing side by an engine control control unit or the like, and the center passage of the first branch port and the second branch port are closed. As a result, the intake air flows from the peripheral wall side passage of the first branch port to the peripheral wall side of the combustion chamber, and generates a swirling flow along the peripheral wall.

Thus, when fuel is injected from the injection valve, the injected fuel mixes with the intake air while the atomization is promoted by the swirling intake air in the combustion chamber.
An air-fuel mixture having a ignitable concentration is formed around the spark plug even with a small amount of injected fuel, so that the entire combustion chamber can burn a lean air-fuel mixture.

[0008] In this case, in the prior art, in order to efficiently form an air-fuel mixture for ignition near the ignition plug disposed substantially at the center of the combustion chamber, fuel is directly supplied from the injection valve to the ignition plug. To be injected.

In another prior art described in, for example, Japanese Patent Application Laid-Open No. 11-22470, a two-way injection type injection valve is used, and fuel is directly injected from this injection valve toward a spark plug. At the same time, the fuel is also injected between the ignition plug and the first branch port toward the swirling intake air.

[0010]

In the prior art described in Japanese Patent Application Laid-Open No. H4-1669, the fuel is injected from the injection valve toward the vicinity of the spark plug. However, there is a problem that the fuel injection cannot be promoted, and the injected fuel adheres to the spark plug, which causes smoldering of the plug and misfire.

In addition, the intake air that has flowed into the combustion chamber in a swirling state may swirl the injected fuel, so that the mixture around the ignition plug becomes lean or rich at the time of ignition. There is a problem that the combustion stability of the air-fuel mixture cannot always be improved during the lean burn control.

On the other hand, in another prior art described in Japanese Patent Application Laid-Open No. 11-22470, although a two-way injection type injection valve is employed, even in this case, fuel is injected toward the vicinity of the ignition plug. As a result, almost the same problem as in the prior art occurs.

Further, in the other prior art, fuel is also injected from the injector to between the spark plug and the first branch port. This injected fuel is separated from the spark plug together with the swirling flow of the intake air. However, there is a problem that the ignition air-fuel mixture cannot be stably formed in the vicinity of the spark plug since the air-fuel mixture is merely formed at the position where the air-fuel mixture is formed.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to promote the atomization of fuel by utilizing a swirling flow of intake air, and to provide an ignition valve near a spark plug. It is an object of the present invention to provide an internal combustion engine capable of stably forming an air-fuel mixture and improving combustion stability during lean burn control.

[0015]

SUMMARY OF THE INVENTION To solve the above-mentioned problems, the present invention provides a cylinder, a cylinder head mounted on the cylinder and defining a combustion chamber between the cylinder, and a cylinder head. An intake port provided on the intake side and formed with first and second branch ports respectively opened to the combustion chamber, a first and second intake valve provided on the cylinder head for opening and closing the respective branch ports, An injection valve for injecting fuel into the combustion chamber via an intake port when each of the intake valves is opened, and a spark plug provided on the cylinder head for burning a mixture of intake air and fuel in the combustion chamber. Applied to internal combustion engines.

The first aspect of the present invention is characterized in that the intake air flows into the combustion chamber from the first branch port on the intake side of the cylinder head, so that the intake air flows into the peripheral wall of the combustion chamber. A swirl flow generating means for generating a swirl flow along the intake air, wherein the injection valve injects fuel from the second branch port toward the combustion chamber to thereby reduce the flow of the injected fuel to the intake air. To form an ignition air-fuel mixture around the ignition plug.

With this configuration, for example, during lean burn control of the internal combustion engine, a swirling flow can be generated in the intake air flowing into the combustion chamber from the first branch port using the swirling flow generating means. Further, the injection valve injects fuel from the second branch port into the combustion chamber, and can form a flow of the injected fuel in the combustion chamber in a direction opposite to a swirling direction of the intake air. As a result, the injected fuel collides with the swirling flow of the intake air along the peripheral wall of the combustion chamber, so that atomization of the fuel can be promoted, and the air-fuel mixture formed by the collision separates from the peripheral wall of the combustion chamber. The mixture flows to the center of the combustion chamber, and an ignition mixture can be formed near the spark plug.

According to the second aspect of the present invention, the swirl flow generating means is provided on the intake side of the cylinder head and is provided between the peripheral wall-side intake passage located in the first branch port on the peripheral wall side of the combustion chamber and the combustion chamber. A partition wall is defined at a center side intake passage located at the center side, and a position is provided at which the center side intake passage defined by the partition wall and the second branch port are opened and closed. And a passage switching valve for allowing the intake air to flow in a swirling state into the combustion chamber only through the peripheral-wall-side intake passage when the valve is closed. It consists of.

Thus, during normal operation of the internal combustion engine,
Since the passage switching valve is kept open, the intake air flows into the combustion chamber through both of the branch ports. At the time of lean burn control of the internal combustion engine, the passage switching valve closes, so that the central intake passage of one branch port and the other branch port are closed, and the intake air is supplied to the peripheral wall intake passage of one branch port. The gas can be swirled into the combustion chamber only through the swirl flow.

According to the third aspect of the present invention, the intake valve includes a valve shaft slidably provided on the cylinder head, and a valve seat provided on the distal end side of the valve shaft on the branch port side in the combustion chamber. The injection valve is configured to inject fuel toward a portion of the second branch port located closer to the peripheral wall of the combustion chamber than the valve shaft of the intake valve.

Thus, the injection valve can inject fuel toward the portion of the second branch port located on the peripheral wall side of the combustion chamber. Therefore, when the intake valve is opened, the injected fuel is caused to flow into the combustion chamber from an opening formed between the valve portion of the intake valve and the valve seat in the vicinity of this portion, so that the injected fuel contains the intake air. And a flow along the peripheral wall of the combustion chamber in a direction opposite to the swirling direction.

According to the invention of claim 4, the injection valve is constituted by an assist air type injection valve which injects fuel together with assist air supplied from an external pressure source.

Thus, the injection valve can accelerate the flow of the injected fuel while promoting the atomization of the injected fuel by using the assist air, so that the injected fuel more strongly collides with the swirling flow of the intake air, Atomization, atomization, and mixing properties of the particles.

Further, according to the fifth aspect of the present invention, the swirl flow generating means is located in the first and second branch ports on the peripheral wall side intake passage located on the peripheral wall side of the combustion chamber and on the center side of the combustion chamber. First and second partitions defined by a center-side intake passage are provided at positions where the respective central intake passages defined by the first and second partitions are opened and closed. A passage switch that allows air to flow into the combustion chamber through all of the first and second branch ports, and allows the intake air to flow in a swirling flow state into the combustion chamber only through each peripheral wall side intake passage when the valve is closed. And an injection valve configured to inject fuel from a peripheral wall side intake passage of the second branch port into the combustion chamber.

Thus, during normal operation of the internal combustion engine,
Since the passage switching valve is kept open, the intake air flows into the combustion chamber through both of the branch ports. During the lean burn control of the internal combustion engine, the passage switching valve is closed, so that the central intake passage of each branch port is closed, and the intake air flows into the combustion chamber only through the peripheral wall intake passage of each branch port. I do. In this case, a swirling flow can be generated by the intake air flowing into the combustion chamber from the first peripheral wall side intake passage, and the fuel injected from the injection valve is guided toward the combustion chamber by the intake air flowing through the second peripheral wall side intake passage. Accordingly, atomization, atomization and mixing of the injected fuel can be improved.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an internal combustion engine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking a 4-valve engine for an automobile as an example.

FIGS. 1 to 5 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a cylinder block constituting a main body of an engine.
Has a plurality of cylinders 2 corresponding to each cylinder of the engine.
(Only one cylinder is shown), and a piston 3 is slidably inserted into each of the cylinders 2.

Reference numeral 4 denotes a cylinder head mounted on the cylinder block 1. The cylinder head 4 is located between the piston 3 and defines a combustion chamber 5 in each cylinder 2. The peripheral wall of the combustion chamber 5 5A is constituted by the inner peripheral surface of the cylinder 2.

Reference numeral 6 denotes an intake port provided on the intake side of the cylinder head 4 for each cylinder 2.
As shown in FIG. 2, the base end is connected to an intake pipe 12 described later. In addition, a first branch port 7 and a second branch port 8 that are branched to both sides around a spark plug 17 described later are formed at the distal end side of the intake port 6, and the first and second branch ports are formed. Reference numerals 7 and 8 open into the combustion chamber 5 at positions closer to the peripheral wall 5A of the combustion chamber 5 than the ignition plug 17. The branch port 7 is defined by a partition wall 14 described later into a peripheral wall side intake passage 7A and a center side intake passage 7B.

Numerals 9 and 10 denote first and second intake valves provided for each of the branch ports 7 and 8 of the cylinder head 4. The first intake valve 9 slides on the cylinder head 4 as shown in FIG. The branch port 7 is opened by separating and seating on a valve shaft 9A movably provided and a valve seat (not shown) substantially similar to a valve seat 11 described later, which is provided on the distal end side of the valve shaft 9A. , And a substantially disc-shaped valve portion 9B to be closed.

The second intake valve 10 also has a valve shaft 10A and a ring-shaped valve seat 11 provided on the cylinder head 4 at the open end side of the branch port 8 in substantially the same manner as the intake valve 9 (see FIG. 1).
And a substantially disk-shaped valve portion 10B which opens and closes the branch port 8. And the intake valves 9.1
Numeral 0 denotes a valve that opens during the intake stroke of each cylinder, and allows intake air to flow into the combustion chamber 5 through the branch ports 7 and 8.

Reference numeral 12 denotes an intake pipe attached to the cylinder head 4 via a gasket or the like. As shown in FIG. 1, the intake pipe 12 is formed as a branch pipe branched from an intake manifold or the like, and the downstream side thereof is an intake pipe. Connected to port 6. On the upstream side of the intake pipe 12, an air cleaner for purifying intake air from the outside, a throttle valve (not shown) for increasing or decreasing the amount of intake air in accordance with a driver's accelerator operation, and the like are provided. I have. Furthermore, the intake pipe 1
In 2, a passage switching valve 15, an injection valve 16, and the like, which will be described later, are provided.

Reference numeral 13 denotes a swirling flow generating device as a swirling flow generating means provided on the engine main body side. The swirling flow generating device 13 includes a partition wall 14 and a passage switching valve 15 described later. I have.

Numeral 14 is a flat partition provided on the intake side of the cylinder head 4. The partition 14 is, as shown in FIG.
A peripheral wall-side intake passage 7A extending in the longitudinal direction inside the first branch port 7 and located on the peripheral wall 5A side of the combustion chamber 5 and a central intake passage 7B located on the center side of the combustion chamber 5 inside the branch port 7
And it is defined. The end of the partition wall 14 extends downstream of the intake pipe 12 together with the intake passages 7A and 7B.

Reference numeral 15 denotes a passage switching valve provided in the intake pipe 12. The passage switching valve 15 is constituted by a butterfly valve or the like having a valve shaft 15A and a valve plate 15B, and receives a signal from a control unit for controlling the engine. By using an electric motor (not shown) or the like, the center side intake passage 7B of the branch port 7 and the branch port 8 are simultaneously opened and closed.

The passage switching valve 15 is held open during normal operation of the engine. In this state, when the intake valves 9 and 10 are opened corresponding to the intake stroke of each cylinder, the intake pipe 1 is opened.
The intake air flowing through the inside 2 flows into the combustion chamber 5 through the entire branch ports 7 and 8.

As shown in FIG. 3, the passage switching valve 15 is closed at the time of lean burn control described later. As a result, when the intake valves 9 and 10 are opened, the intake air flows into the combustion chamber 5 from the peripheral wall side intake passage 7A of the branch port 7 as shown by the arrow A, and the intake air burns as shown by the arrow B. A swirling flow occurs substantially along the peripheral wall 5A of the chamber 5.

Reference numeral 16 denotes an assist air type injection valve provided in the intake pipe 12. As shown in FIG. 3, the injection valve 16 supplies a part of the intake air as assist air from an air pump (not shown) or the like. Accordingly, when the intake valves 9 and 10 are opened, the fuel F is injected together with the assist air, and at this time the fuel flow is accelerated while promoting the atomization of the injected fuel by the assist air. I have.

Here, the injection valve 16 injects the fuel F in the direction of arrow C into the opening of the second branch port 8 when the intake valve 10 is opened as shown in FIG. In advance. Then, the fuel F injected from the injection valve 16 has an annular shape formed between the open end (valve seat 11) of the branch port 8 and the valve shaft 10A of the intake valve 10, as shown in FIGS. Of the opening area S1, a fan-shaped peripheral wall side area S located closer to the peripheral wall 5A of the combustion chamber 5 than the valve shaft 10A.
2 and flows into the combustion chamber 5.

In this case, the peripheral wall side area S2 is defined as a branch port 8 having an angle α of, for example, about 40 to 50 ° with respect to a straight line L-L connecting the centers O1, O2 of the intake valves 9, 10.
It is defined as a fan-shaped range sandwiched between a straight line O2 -L1 and a straight line LL inclined to the side. Then, the fuel F injected from the injection valve 16 flows such that the cross section S3 of the jet trajectory substantially falls within the range of the peripheral wall side area S2, and the valve portion 10B of the intake valve 10 and the valve seat 1
Pass between 1.

Thus, the fuel F flows into the combustion chamber 5 from the branch port 8 substantially along the peripheral wall 5A of the combustion chamber 5,
By flowing in the direction indicated by the arrow D in the combustion chamber 5 in a direction opposite to the swirling direction of the intake air, the air collides with the swirling flow of the intake air at a position close to the peripheral wall 5A of the combustion chamber 5 to promote atomization. Then, the fuel F is mixed with the intake air while flowing in the atomized state while flowing in the radial direction away from the peripheral wall 5A together with the intake air.
A mixture G for ignition is formed as shown in FIG.
Reaches the vicinity of the spark plug 17 at the ignition timing corresponding to the combustion stroke of each cylinder.

Reference numeral 17 denotes an ignition plug provided at the cylinder head 4 at a position substantially at the center of the combustion chamber 5. The ignition plug 17 comprises a fuel F injected from an injection valve 16 and intake air as shown in FIG. The mixture G is burned in the combustion chamber 5.

In FIG. 1, reference numeral 18 denotes an exhaust port provided in the cylinder head 4 and opened into the combustion chamber 5 of each cylinder, and 19 denotes a pair of exhaust valves (only one exhaust valve) for opening and closing each exhaust port 18. In the drawing, the exhaust valves 19 are each opened during the exhaust stroke of each cylinder to discharge the exhaust gas after combustion of the air-fuel mixture G from each exhaust port 18 to the outside.

The four-valve engine according to the present embodiment has the above-described configuration, and its operation will now be described.

First, during normal operation of the engine, the passage switching valve 15 is kept open, and when the intake valves 9 and 10 are opened during the intake stroke of each cylinder, both intake air from the intake pipe 12 is released. Flows into the combustion chamber 5 through the entirety of the branch ports 7 and 8. At this time, when fuel is injected from the injection valve 16, the injected fuel forms a mixture with the intake air, and this mixture is ignited by the ignition plug 17 at the ignition timing of each cylinder, explosively combusts, and Causes the engine to operate normally.

For example, when lean burn control of the engine is performed in accordance with the operating state of the vehicle, the passage switching valve 15 is closed as shown in FIG. 3, and the central intake passage 7B of the branch port 7 and the branch port 8 are connected. Is closed. As a result, when the intake valves 9 and 10 are opened, the intake air flows into the combustion chamber 5 only through the peripheral-wall-side intake passage 7A of the branch port 7 as indicated by the arrow A, while flowing into the peripheral wall 5A of the combustion chamber 5. It turns substantially along arrow B, and a strong swirling flow is generated in the intake air.

At this time, the injection valve 16 is connected to the passage switching valve 15
As a result, the fuel F is injected together with the assist air into the branch port 8 where the flow of the intake air is substantially blocked. When the intake valve 10 is opened, the fuel F flows into the combustion chamber 5 through the peripheral wall opening S2 in FIG.
3 flows in the direction indicated by the arrow D in FIG. 3 in a direction substantially opposite to the swirling direction of the intake air.

As a result, the fuel F collides with the swirling flow of the intake air and atomizes while igniting the fuel-air mixture G with the intake air.
And flows radially toward the periphery of the spark plug 17. Then, the mixture G reaches the vicinity of the ignition plug 17 at the ignition timing of each cylinder, and is burned by the ignition plug 17.

Thus, in the present embodiment, the swirling flow of the intake air is caused to flow in the combustion chamber 5 by using the swirling flow generator 13 to flow the intake air into the combustion chamber 5 from the first branch port 7 side. At the same time, the injection valve 16 is configured to inject the fuel F into the combustion chamber 5 from the second branch port 8 side, so that the fuel F is directed in the combustion chamber 5 in a direction opposite to the swirling direction of the intake air. The flow of the fuel F can collide with the swirling flow of the intake air.

Thus, the atomization of the fuel F can be promoted by the collision with the intake air, and the fuel F is atomized in the intake air to stably form the air-fuel mixture G for ignition. G can be circulated toward the vicinity of the spark plug 17.

In this case, the injection valve 16 includes the valve shaft 1 of the intake valve 10 of the annular opening area S1 formed between the valve portion 10B and the opening of the branch port 8 when the intake valve 10 is opened.
The fuel F is injected toward the peripheral wall side area S2 located closer to the peripheral wall 5A of the combustion chamber 5 than 0A.

Therefore, when the intake valve 10 is opened, the fuel F that has flowed into the combustion chamber 5 from the peripheral wall side area S2 is substantially directed along the peripheral wall 5A of the combustion chamber 5 in a direction opposite to the swirling direction of the intake air. Can be distributed. Then, the fuel F and the intake air collide at a position close to the peripheral wall 5A of the combustion chamber 5,
The mixture G can be radially circulated toward the periphery of the ignition plug 17 so as to be separated from the peripheral wall 5A.

Therefore, according to the present embodiment, a good mixture G can be formed near the ignition plug 17 by mixing the fuel F and the intake air by using the swirling flow of the intake air. Combustion stability during control can be improved.

Further, since the swirling flow generating device 13 includes the partition wall 14 defining the peripheral wall side intake passage 7A and the center side intake passage 7B in the branch port 7, and the passage switching valve 15, the lean burn control is performed. In some cases, the center side intake passage 7B and the branch port 8 can be simultaneously closed by the passage switching valve 15,
The intake air flows from the peripheral wall side intake passage 7A to the peripheral wall 5A of the combustion chamber 5.
And a strong swirling flow can be generated along the peripheral wall 5A.

On the other hand, since the assist air type injection valve 16 is used, the flow of the injected fuel can be accelerated while promoting the atomization of the injected fuel using the assist air. Even when the flow of intake air is substantially blocked at the side, the fuel injected into the branch port 8 can be satisfactorily mixed with the intake air by flowing into the combustion chamber 5 while atomizing by the assist air. .

Next, FIG. 6 shows a second embodiment according to the present invention. The feature of this embodiment lies in that a partition wall of the swirling flow generating means is provided in both intake ports. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 31 denotes a cylinder head of the engine according to this embodiment. The cylinder head 31 is provided with an intake port 32 corresponding to each cylinder 2 in substantially the same manner as in the first embodiment. The intake port 32 is formed with a first branch port 33 and a second branch port 34 that open into the combustion chamber 5, respectively, and has an intake pipe 35 attached thereto.

Numeral 36 denotes a swirling flow generating device as a swirling flow generating means provided on the engine body side. The swirling flow generating device 36 includes first and second partition walls 37 and 38, which will be described later, and a passage switching valve. 39.

Reference numeral 37 denotes a first partition provided in the first branch port 33. The partition 37 has a peripheral wall formed in the first branch port 33 in substantially the same manner as the partition 14 according to the first embodiment. The side intake passage 33A and the center side intake passage 33B are defined.

Numeral 38 denotes a second partition provided in the second branch port 34. The partition 38 is provided with the second branch port 34.
The inside is defined as a peripheral wall side intake passage 34A and a center side intake passage 34B. Further, the second peripheral wall side intake passage 34A is
Compared to the first peripheral wall side intake passage 33A, for example, 1/4
Formed with a small channel area of about 1/3,
Of the first central side intake passage 33.
B has a larger flow area than B.

Reference numeral 39 denotes a passage switching valve provided in the intake pipe 35, such as a butterfly valve, and the like.
Almost in the same manner as the passage switching valve 15 described in the above embodiment, the passage switching valve 15 includes a valve shaft 39A and a valve plate 39B, and the valve plate 39B is driven in the valve opening direction via the valve shaft 39A during lean burn control.

However, the passage switching valve 39 is connected to the branch port 3
The central side intake passages 33B and 34B of the three and 34 are simultaneously opened,
It is closed. When the passage switching valve 39 is closed for performing the lean burn control, when the intake valves 9 and 10 are opened during the intake stroke of each cylinder, a part of the intake air is supplied from the peripheral wall side intake passage 33A to the arrow A. ′ Flows into the combustion chamber 5. At this time, the intake air is supplied to the peripheral wall side intake passage 34A.
From the peripheral wall-side intake passage 3.
4A has a smaller flow area than the peripheral-wall-side intake passage 33A, so that a swirling flow is generated in the intake air in the combustion chamber 5 as indicated by an arrow B '.

Reference numeral 40 denotes an injection valve provided on the cylinder head 31. The injection valve 40 is a normal specification injection valve for injecting fuel without using assist air or the like. , Partition wall 38 located on the combustion chamber 5 side
The fuel F 'is injected in the direction indicated by the arrow C' toward the tip of the fuel cell.

During the lean burn control, the fuel F 'injected from the injection valve 40 in the direction of arrow C' is guided to the combustion chamber 5 by the intake air in the direction of arrow E flowing through the peripheral wall side intake passage 34A. . As a result, the fuel F 'flows into the peripheral wall 5A side of the combustion chamber 5 while being atomized by the intake air in the peripheral wall side intake passage 34A, and flows along the peripheral wall 5A substantially as indicated by an arrow D'. The gas flows in the direction opposite to the swirling flow and collides with the swirling flow to form an air-fuel mixture G '.

Thus, also in the present embodiment configured as described above, it is possible to obtain substantially the same operation and effect as in the first embodiment. And especially in this embodiment,
By providing the partition walls 37 and 38 at the branch ports 33 and 34, respectively, when the passage switching valve 39 is opened, the swirling flow is caused by the intake air in the arrow A 'direction flowing into the combustion chamber 5 from the peripheral wall side intake passage 33A into the combustion chamber 5. The peripheral wall side intake passage 34
The fuel F 'is injected from the injection valve 40 into the intake air in the direction of the arrow E flowing through A.

Thus, the flow of the fuel F 'can be accelerated while promoting the atomization of the fuel F' injected from the injection valve 40 by using the intake air flowing in the direction indicated by the arrow E flowing in the peripheral wall side intake passage 34A. This fuel F 'can strongly collide with the swirling flow of the intake air in the combustion chamber 5 without using an assist air type injection valve or the like, and the atomization and mixing properties can be improved.

In the first embodiment, the inside of the branch port 7 is formed by using the flat partition wall 14 to form the peripheral-wall-side intake passage 7.
A and the center side intake passage 7B are defined, but the present invention is not limited to this. For example, a pipe is provided in the intake port, and one of the spaces inside and outside the pipe is defined as the peripheral wall side intake passage. And the other space may be used as the center side intake passage,
Further, the peripheral wall side intake passage or the center side intake passage may be formed using an auxiliary passage provided separately from the intake port for the cylinder head. Further, in the second embodiment, by forming the partition walls 37 and 38 using a pipe material or the like, the opening and closing operations of the passage switching valve 39 can be stabilized.

[0068]

As described in detail above, according to the first aspect of the present invention, the swirling flow generating means swirls the intake air by flowing the intake air into the combustion chamber from the first branch port of the intake ports. A flow is generated, and the injection valve is configured to inject fuel from the second branch port to the combustion chamber side and collide with the swirl flow of the intake air, so that the injected fuel flows in a direction opposite to the swirl flow of the intake air. Thus, the injected fuel can collide with the swirling flow at a position close to the peripheral wall of the combustion chamber. As a result, the atomization of the injected fuel can be promoted, the mixing property between the injected fuel and the intake air can be improved, and the mixture can be circulated toward the vicinity of the ignition plug so as to be away from the peripheral wall of the combustion chamber. it can. Therefore, a favorable ignition air-fuel mixture can be formed in the vicinity of the ignition plug using the swirling flow of the intake air, and for example, combustion stability during lean burn control can be improved.

According to the second aspect of the present invention, the swirl flow generating means includes a partition that defines the inside of the first branch port into a peripheral-wall-side intake passage and a central-side intake passage; Since the second branch port and the passage switching valve for opening and closing the second branch port are configured, for example, at the time of the lean burn control, the passage switching valve can close the center side intake passage and the second branch port, and the intake air is removed from the first branch port. Can flow into the peripheral wall side of the combustion chamber only through the peripheral wall side intake passage of the branch port, and generate a strong swirling flow along the peripheral wall of the combustion chamber.

Further, according to the third aspect of the invention, the injection valve is configured to inject fuel toward a portion of the second branch port which is located closer to the peripheral wall of the combustion chamber than the valve shaft of the intake valve. Therefore, when the intake valve is opened, the injected fuel can flow into the combustion chamber from an opening formed between the valve portion and the valve seat of the intake valve on the peripheral wall side of the combustion chamber, and thereby the injected fuel On the other hand, a flow substantially along the peripheral wall of the combustion chamber in a direction opposite to the swirling direction of the intake air can be given.

According to the fourth aspect of the present invention, since the assist air type injection valve is used, the injection valve can accelerate the flow of the injected fuel while promoting the atomization of the injected fuel by using the assist air. In addition, the injected fuel can more strongly collide with the swirling flow of the intake air, and the atomization and mixing of the injected fuel can be improved.

Further, according to the fifth aspect of the present invention, the swirling flow generating means defines the first and second branch ports as a peripheral wall side intake passage and a center side intake passage, respectively. The injection valve includes a partition wall and a passage switching valve that opens and closes a central intake passage of each branch port. The injection valve has a flow passage area smaller than that of the first peripheral wall intake passage. Since the fuel is injected from the intake passage into the combustion chamber, a swirling flow can be formed in the combustion chamber by the intake air flowing through the first peripheral wall side intake passage, and the intake air flowing through the second peripheral wall side intake passage can be formed. Using air, the flow of the injected fuel can be accelerated while promoting atomization of the fuel injected from the injection valve. This makes it possible to cause the injected fuel to strongly collide with the swirling flow of the intake air in the combustion chamber without using, for example, an assist air type injection valve or the like, thereby further improving the atomization and mixing properties.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an automobile engine according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a cylinder head and the like of an automobile engine from the direction of arrows II-II in FIG.

FIG. 3 is a cross-sectional view showing a state where intake air and injected fuel are being supplied to an intake valve of an automobile engine, at a position substantially similar to FIG. 2;

FIG. 4 is an enlarged view of a main part in FIG. 3 showing a direction of fuel injection by an injection valve.

FIG. 5 is an explanatory diagram showing a relationship between an intake valve and a fuel injection direction as viewed from a front direction of the intake valve.

FIG. 6 is a cross-sectional view showing an automobile engine according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 cylinder block 2 cylinder 3 piston 4, 31 cylinder head 5 combustion chamber 5A peripheral wall 6, 32 intake port 7, 33 first branch port 7A, 33A, 34A peripheral wall side intake path 7B, 33B, 34B central side intake path 8, 34 Second branch port 9,10 Intake valve 9A, 10A Valve shaft 9B, 10B Valve portion 11 Valve seat 12,35 Intake pipe 13,36 Swirl flow generating device (Swirl flow generating means) 14,37,38 Partition wall 15, 39 passage switching valve 16,40 injection valve 17 spark plug

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 69/00 360 F02M 69/00 360C 69/04 69/04 GR (72) Inventor Takao Noguchi Kanagawa 1370 Onna, Atsugi-shi, inside Unisia Gex Co., Ltd. (72) Inventor Tsuyoshi Kobayashi 1370 Onna, Atsugi-shi, Kanagawa Prefecture, Japan F-term 3G023 AA07 AB01 AC02 AD03 AD05 AD07 AD09 AG02

Claims (5)

[Claims] A cylinder head mounted on the cylinder and defining a combustion chamber between the cylinder and the cylinder;
An intake port provided on the intake side of the cylinder head and having first and second branch ports opened to the combustion chamber, and a first and a second port provided on the cylinder head for opening and closing the respective branch ports. A second intake valve, an injection valve that injects fuel into the combustion chamber via an intake port when each of the intake valves is opened, and a mixture of the intake air and fuel provided in the cylinder head. An internal combustion engine comprising: a spark plug that burns in the combustion chamber; wherein, on the intake side of the cylinder head, intake air flows into the combustion chamber from the first branch port along the peripheral wall of the combustion chamber. A swirling flow generating means for generating a swirling flow in the intake air; wherein the injection valve injects fuel from the second branch port toward the combustion chamber to thereby flow the injected fuel. Internal combustion engine, characterized in that the arrangement for forming a mixture for ignition around the spark plug collides with swirling flow of the intake air. 2. The swirling flow generating means is provided on an intake side of the cylinder head, and is located in the first branch port on a peripheral wall side intake passage located on a peripheral wall side of a combustion chamber and on a center side of the combustion chamber. A partition defined by the center-side intake passage, and a center-side intake passage defined by the partition and the second branch port are provided at positions for opening and closing. A passage switching valve that permits the air to flow into the combustion chamber through all of the second branch ports and, when the valve is closed, allows the intake air to flow in a swirling state into the combustion chamber only through the peripheral-wall-side intake passage. The internal combustion engine according to claim 1, comprising: 3. An intake valve, comprising: a valve shaft slidably provided on the cylinder head; and a valve portion provided on a distal end side of the valve shaft and detachably seated on a valve seat on a branch port side in the combustion chamber. 3. The injection valve according to claim 1, wherein the injection valve is configured to inject fuel toward a portion of the second branch port that is located closer to a peripheral wall of the combustion chamber than a valve shaft of the intake valve. 4. Internal combustion engine. 4. The internal combustion engine according to claim 1, wherein said injection valve comprises an assist air type injection valve for injecting fuel together with assist air supplied from an external compressed air source. 5. The method according to claim 1, wherein the swirling flow generating means is configured to control the first, second, and
A first and a second partition walls defining a peripheral wall side intake passage located on the peripheral wall side of the combustion chamber and a central side intake passage located on the central side of the combustion chamber, respectively, within the branch port of The central side intake passage defined by the two partition walls is provided at a position to open and close, and when the valve is opened, it prevents the intake air from flowing into the combustion chamber through all of the first and second branch ports. And a passage switching valve for allowing the intake air to flow into the combustion chamber in a swirling state only through each of the peripheral wall side intake passages when the valve is closed, wherein the injection valve is a peripheral wall side intake passage of the second branch port. The internal combustion engine according to claim 1, wherein fuel is injected into the combustion chamber from the fuel cell.