JP2697513B2 - Intake port structure of 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 port structure of an internal combustion engine, and more particularly, to a stratified intake flow from an intake port having a combustion chamber opening opened and closed by two intake valves. The present invention relates to an intake port structure of an internal combustion engine configured to generate a tumble flow.

[0002]

2. Description of the Related Art In recent years, in order to increase the intake passage area of a combustion chamber of an engine without increasing the size of an intake valve, an internal combustion engine provided with two intake port passages in one combustion chamber has been used. ing. In such an internal combustion engine, 2
One intake port passage is formed so as to branch off from one intake port, and the air-fuel mixture flows from each of these two intake port passages into the combustion chamber (hereinafter, such an internal combustion engine is taken into two intake ports). Port-type internal combustion engine).

As means for improving the combustion of the internal combustion engine, in the intake stroke, for example, a vertical swirling flow in a cylinder as shown in FIGS.
a, Fm) is effective. For example, FIGS. 22 and 23 show the structure of one cylinder of a two-intake-port internal combustion engine that generates the tumble flows Fa and Fm. In the drawings, reference numeral 22 denotes a cylinder block, 24 denotes a cylinder bore, and 26 denotes a cylinder bore. Is a piston, 28 is a cylinder head, and 30 is a combustion chamber. Reference numeral 34 denotes a pent roof formed on the upper wall portion of the combustion chamber 30.
Reference numerals 0 'and 42' denote branch portions of the intake port 44 ', two passage portions of the intake port provided for each cylinder (hereinafter, referred to as intake port portions).
Each of the intake valves 58 is provided.

[0004] The pent roof 34 is provided with each intake port portion 4.
The intake air flows from the intake passages 40 ',
The pentroof 34 is provided with a slope that can be guided downward along the inner wall surface of the cylinder bore 24 on the extension axis of the 2 ′.
Of the tumble flow as indicated by arrows Fa and Fm, respectively.

Further, in order to promote the tumble flow, the shape of the intake port 44 'is important.
2, the intake port 44 'is formed as a straight straight port as shown in FIG. 23, or the intake port 44' is narrowed as shown in FIG. 26 to rectify the flow. . In FIGS. 22 and 26, reference numerals 40F and 42F indicate normal intake ports that are not straight ports.

The cross-sectional shape of such an intake port 44 'is generally formed in a circular shape as shown in FIG. 24, but is formed in an elliptical shape or an oblong shape as shown in FIG. May be formed. Also, in this example,
As shown in FIG. 23, the injector 12 is provided only in one intake passage 42 ′, and the ignition plug 11 is disposed near the intake valve 58 in the intake passage 42 ′ equipped with the injector 12. Therefore, this spark plug 11
, A mixture of the fuel injected from the injector 12 and the intake air flows into the combustion chamber 30 through the intake passage 42 'and the intake port 44' to form a tumble flow Fm of the mixture. . From the intake port 44 'of the intake port portion 40', only air flows into the combustion chamber 3 '.
0, a tumble flow Fa of this air is formed.

As a result, a stratified tumble flow of the tumble flow Fm of the air-fuel mixture and the tumble flow Fa of the air is formed in the combustion chamber 30. The tumble flow (tumble swirl) generated in this manner is effective in increasing the flame propagation speed and the combustion stability. When experimental data on the heat generation amount Q, the in-cylinder pressure P, and the heat generation rate dQ are shown, for example, FIG.
The tumble swirl (when the tumble flow is generated) is larger in the heat generation amount Q, the in-cylinder pressure P, and the heat generation rate dQ than the standard (the general case where the tumble flow is not particularly generated). It can be seen that the cycle fluctuation is small and the combustion stability is good.

Accordingly, the engine can be operated in a stable state even in a state where the fuel concentration of the air-fuel mixture is low, that is, during lean combustion. In the figure, reference numeral 47 denotes an exhaust port communicating with the exhaust passage 60, and 59 denotes an exhaust valve.

[0009]

By the way, in a two-intake-port internal combustion engine which generates such tumble flows Fa and Fm, the ignition plug 11 is equidistant from the centers of the two intake valves 58 and 58. When located (eg, at the center of the top of the combustion chamber), a rich tumble flow of the air-fuel mixture is formed near the spark plug 11 in the combustion chamber 30 (ie, near the center of the combustion chamber 30) to form a stratified intake air. Need to be Further, by stratifying the intake air flow in this way, it is desired to rectify the intake air flow and promote the formation of a tumble flow. However, if the two intake port portions 40 ', 42' are arranged in parallel, it is difficult to stratify the air-fuel mixture sucked from both the intake valves 58, 58, and the engine will not work during lean combustion. There is a problem that the combustion state cannot be maintained in a stable state.

[0010] On the other hand, Japanese Patent Application Laid-Open No.
No. 60-233314 discloses that the intake valve of the intake passage is
A pair of partitions is provided upstream from the
Into a central passage and side passages on both sides of the central passage,
A control valve that closes when the engine load is low is located upstream of the central passage.
And the central passage at the downstream end of the central passage.
Provide a dividing wall that divides into two, and the center between the dividing wall and the control valve
A fuel injection valve is placed in the passage, and the fuel injection valve is
To form a communication opening communicating the central passage and the side passage
What has been proposed. This is for low load operation
Fully closes the central passage with a control valve and
Into the branch passage at the downstream end of the central passage through the passage opening
And mix it with the injected fuel to form a rich mixture around the spark plug.
To ensure ignitability in stratified combustion, and
During operation, the control valve is fully opened to obtain high filling efficiency.
Is what you do. However, with such technology,
During low load operation, fuel is
A strong swirl flow occurred in the firing chamber, causing turbulence
Flow from the communication opening to the center of the combustion chamber through the central passage.
The ignitability may be impaired due to the diffusion of the air-fuel mixture
You. Also, during high load operation, the control valve is fully open
There is a problem that the control valve itself becomes a flow path resistance. further
Is a so-called helicopter whose side passage runs along the cylinder wall
Port so that it flows in from the side passage
Side-effects such that incoming air collides with each other in the combustion chamber.
Whirl, and the intake air flowing from the central passage further increases
Filling efficiency is not good due to collision with horizontal swirl
There are issues. Also, Japanese Utility Model Application No. 61-165660 (Japanese Utility Model Application)
No. 63-71423)
Disclosure of technology with control valve that opens on highway during high load operation
Have been. This control valve is closed during low load operation.
By closing the outer intake port,
Inlet mixture with low interference from port
Generates a vertical swirl and opens the control valve during high-load operation
Opening the outside intake port to increase the charging efficiency
To ensure the required amount of air-fuel mixture at high load.
Things have been suggested. However, such technology
So at the time of low load operation, electrically from inside the intake port
The incoming air-fuel mixture flows into the combustion chamber and creates a powerful vertical swirl.
A stream is formed, but this vertical swirl simply surrounds the spark plug
It only forms an ignitable fuel-air mixture.
The entire combustion chamber is empty because the port is closed by a control valve
There is a problem that the fuel ratio cannot be made lean.
Also, the presence of the control valve itself becomes the flow path resistance,
The vertical swirl of the air-fuel mixture introduced from the intake port and the outside
Filled by collision with horizontal swirl introduced from intake port
There is a problem that efficiency is low. Also, any of the above
In the technology described above, it is necessary to adjust the control valve and the opening of the control valve.
And a cost increase.
is there. The present invention has been made in view of the above problems,
Promotes stratification of the tumble flow of intake air in the cylinder, and thickens the air-fuel ratio of the tumble flow on the ignition means side of the combustion chamber;
It is an object of the present invention to provide an intake port structure of an internal combustion engine in which the air-fuel ratio of a tumble flow on both sides thereof is reduced so that a stable lean combustion state can be maintained even with a fuel mixture having a smaller amount than the stoichiometric air-fuel ratio. I do.

[0011]

According to a first aspect of the present invention, there is provided an intake port structure for an internal combustion engine including an intake port having two combustion chamber openings which are respectively opened and closed by two intake valves. In an internal combustion engine configured such that an intake air flow from the intake port becomes a tumble flow in the combustion chamber, an ignition means disposed at a central portion of a top portion of the combustion chamber; The intake port is divided into a central passage on the ignition means side and side passages on both sides of the ignition port.
And One of the partition walls, are disposed on the upper surface or near the intake port, the fuel injection means for injecting fuel toward the lower side of the central side passage is provided in the intake port, intake Kipo
The cross-sectional area of the central side passage and the side passage of the
It is characterized in that it is configured to be constant regardless of the operating state .

According to a second aspect of the present invention, an intake port structure for an internal combustion engine according to the present invention has the following features.
The partition wall extends from the lower inner wall of the intake port to the upper inner wall. According to a third aspect of the present invention, in the intake port structure for an internal combustion engine according to the present invention, in addition to the configuration of the first aspect, a space is provided between the partition and the inner wall on the upper surface of the intake port. Features.

[0013]

In the intake port structure for an internal combustion engine according to the first aspect of the present invention, intake air is sent into the combustion chamber from an intake port having two combustion chamber openings opened and closed by two intake valves, and the tumble flow is generated. A flow is formed. At this time, inside the intake port, the partition wall divides the internal intake air into a central passage on the side of the ignition means and side passages on both sides thereof. Also,
Fuel is injected downward from the upper surface side of the central passage by the fuel injection means and mixed with the intake air flow. Therefore, the center
A tumble flow (vertical swirl) of the mixture is formed in the
A substantially tumble flow of air is formed on both sides. Also this
All three tumble flows are directly on the cylinder center axis.
Formed in a laminar tumble flow swirling around intersecting axes
Therefore, the filling efficiency is improved without colliding with each other. Ma
In addition, the passage cross-sectional area of the center side passage and the side passage of the intake port
Is constant regardless of the engine operating state,
The flow path resistance does not change according to the state.

Then, only the air-fuel mixture flows into the central passage and only the air flows into the side passages due to the above-mentioned partition, so that the intake air flowing into the combustion chamber has a relatively high fuel concentration. And a tumble flow of air is formed on both sides of the tumble flow. With such a structure, the combustion state is reliably stabilized by forming a tumble flow of the air-fuel mixture which is lean in the entire combustion chamber as a whole on the ignition means side.

Also, as in the case of the intake port structure for an internal combustion engine according to the present invention, the partition wall is formed from the lower inner wall to the upper inner wall of the intake port. The layer and the layer of air are completely separated and flow into the combustion chamber. Further, as described above, since the fuel is injected from the upper surface side of the intake port toward the lower side of the intake port, the partition wall and the intake port are formed as in the intake port structure of the internal combustion engine according to the third aspect of the present invention. Even in the case where a space is provided between the upper surface of the port and the upper surface of the port, the partition walls stratify the tumble flow between the air-fuel mixture layer and the air layer in the combustion chamber.

[0016]

1 to 6 show an intake port structure of an internal combustion engine according to a first embodiment of the present invention, and FIG. FIG. 2 is a schematic top view showing the configuration, and is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is a schematic partial cross-sectional view showing the configuration. FIG. 4 is a schematic partial cross-sectional view showing the configuration, and is a BB cross-sectional view in FIG. 3, FIG. 5 is a schematic view showing the operation thereof, and FIGS. 6 (a) to 6 (d) show the fuel thereof. FIGS. 7 to 10 are schematic diagrams showing variations in the manner of injection, and FIGS. 7 to 10 are graphs for explaining the operation and effect, respectively.

As shown in FIG. 1, each cylinder of the internal combustion engine having the intake port structure of the first embodiment has a cylinder bore 24 formed in a cylinder block 22 and a piston 2.
6 and the cylinder head 28, a combustion chamber 30 is formed. In the combustion chamber 30, an intake port 46 is provided.
Has been led. The intake port 46 is a siamese port that is divided into two intake port portions 46A and 46B by a port partition (intake port branch portion) 46C on the way.
An intake valve 58 is provided at each of the combustion chamber openings 6B. The exhaust port 47 is also a siamese port, and two exhaust ports are provided in the combustion chamber 30.
Portions 47A and 47B are also guided, and exhaust valves (not shown) are provided.

Each of the intake port portions (hereinafter, this intake port portion is also simply referred to as an intake port) 46A,
Reference numeral 46B is connected to an intake passage (intake manifold) (not shown). Further, in the drawing, 1A and 1B indicate the respective axes of the intake ports 46A and 46B. In addition, the exhaust ports 47A and 47B merge on the downstream side,
It is also connected to a common exhaust passage 47.

In the vicinity of the branch portion 46C of the intake ports 46A and 46B, an injector 12 as a fuel injection means described later is mounted.
Thus, the fuel is injected into the intake ports 46A and 46B. In this embodiment, on the downstream side of the vicinity of the branch portion 46C of the intake ports 46A and 46B,
Each intake port 46A, 46B is formed parallel to each other. Thereby, the intake air from each intake port 46A, 46B flows into the combustion chamber 30 in a state of being parallel to each other.

As shown in FIGS. 2, 3 and 5, the axial lines 1A and 1B of the intake ports 46A and 46B are two straight lines parallel to each other. That is, the intake ports 46A and 46B are formed as straight straight ports parallel to each other. Further, as shown in FIG.
The tumble flow side halves of A and 46B (that is, the upper halves of the intake ports 46A and 46B through which the main component flow forming the tumble flow flows) 46A-1 and 46B-1 block the other half (that is, the tumble flow). Port 4 through which such component flows
6A and 46B are wider than the lower halves 46A-2 and 46B-2, and the intake convergence F1 of the intake ports 46A and 46B is located on the tumble flow side (that is, the intake ports 46A and 46B).
B are eccentric to the upper half 46A-1 and 46B-1). Thus, the intake air flows from the intake ports 46A and 46B easily form a tumble flow in the combustion chamber 30. In the first embodiment, the intake ports 46A, 46
B is formed to have a substantially inverted triangular cross section as shown in FIG.

Further, as shown in FIG.
A concave portion 35 is formed on the top surface of the cylinder so that a space is secured between the cylinder head 28 and the piston 26 when the piston 26 reaches the top dead center. And piston 2
The top surface of 6 is also provided with a protruding portion 39 protruding from the recess 35 in the vicinity of the recess 35. This bump 3
9 is a slope 3 formed between the raised portion 39 and the recess 35.
7, it is smoothly connected to the recess 35.

The recess 35 is formed below an exhaust valve (not shown).
8 is formed below. Therefore, as shown in FIG. 1, the tumble flow side half 4 of the intake ports 46A, 46B is formed.
Intake air flows Fa and Fm flowing from 6A-1 and 46B-1
From the recess 35 to the raised portion 39 via the slope 37, thereby facilitating the formation of a tumble flow.

As shown in FIGS. 1 and 5, a spark plug 11 as ignition means is provided at the center of the top above the combustion chamber 30, and the intake ports 46A, 4
6B on the reference plane 3. Here, the reference plane 3 is an imaginary plane located at the center of both the intake ports 46A and 46B. As shown in FIGS. 1 to 3 and 5, a partition 21 is provided in each of the intake ports 46A and 46B so as to bisect the inside of each of the intake ports 46A and 46B in the left-right direction. In each of the intake ports 46A and 46B, a passage (center side passage on the spark plug side) 4 on the reference surface 3 side of the intake flow and a passage outside the reference surface 3 (side passages on both sides of the center side passage). 5 is divided into two along the flow direction of the intake air.

As shown in FIGS. 2 and 3, the partition wall 21 is formed substantially vertically along the axial lines 1A and 1B of the intake ports 46A and 46B. It extends over the downstream side. Also,
These partition walls 21 and 21 are arranged substantially in parallel with each other, and the intake valve 5 is located downstream of the intake ports 46A and 46B.
8 extends along the axis 2 to the vicinity of the stem portion 57 and the umbrella portion 56 of the intake valve 58. Further, the partition 21 does not contact the umbrella portion 56 or the stem portion 57 of the intake valve 58,
They are formed with an appropriate clearance secured between them, so that the operation of the intake valve 58 is not affected at all.

In the first embodiment, the partition wall 21 is formed from the upper inner wall 8 to the lower inner wall 7 of the intake ports 46A, 46B.
The inside of 6B is divided into a center side passage 4 and a side passage 5. Thereby, the intake ports 46A, 46B
Inside, the flow branched into the central passage 4 and the side passage 5 flows into the combustion chamber 30 while being separated from each other while being rectified by the partition 21. Accordingly, the flow of the intake air flows into the combustion chamber 30 due to the partition wall 21 as shown in FIG. 5, and the air-fuel mixture layer Fm and the air-only layer Fm are mixed with the air.
a and Fa (three flows of the central side passage 4 and the side passages 5 on both sides thereof) in a separated state, that is, a tumble flow is formed in a layered state. I have. Therefore, the present internal combustion engine is configured as a stratified combustion internal combustion engine.

In the intake ports 46A and 46B,
Since the cross-sectional area of the intake ports 46A and 46B is reduced by the cross-sectional integral of the partition 21, the flow coefficient of the intake ports 46A and 46B may be reduced and the fully open engine performance may be reduced. Therefore, the intake ports 46A, 46B
As shown by the hatched portion 13 in FIGS. 2 and 4, the upper half portions 46A-1 and 46B-1 of the substantially inverted triangular cross section are sufficiently large so as to cancel out the cross-sectional integration, and the engine is fully opened. The flow coefficient at the time is secured.

Further, as described above, it is desirable to reduce the cross-sectional area of the partition 21 as much as possible in order to secure a flow rate coefficient. For this reason, the partition 21 is formed so as to be as thin as possible. In the present embodiment, as shown in FIG. 2, the thickness of the partition 21 is equal to the diameter of the valve stem 57,
Or, it is slightly thinner. As a result, the valve stem 5 is secured while ensuring the intake flow rate of the intake port 46.
7 can reduce the intake resistance, and the intake air smoothly flows into the combustion chamber 30.

FIG. 5 shows a modified example of the partition 21. The thickness of the partition 21 is formed as thin as possible on the upstream side of the valve stem 57, and gradually decreases as approaching the valve stem 57. The valve stem 57 may be formed so as to have a thickness substantially equal to the diameter of the valve stem 57.
As a result, the flow of the intake flow near the valve stem 57 can be further adjusted.

In the modified example shown in FIG.
Although the upstream end of the fuel injection valve 1 is formed in the middle of the intake port 46, the partition wall 21 divides the air-fuel mixture and the air into the central passage 4 and the side passage 5, and the fuel mixture injected from the injector 12 is removed. It suffices if diffusion to the side passage 5 can be prevented.
The upstream end of 1 does not necessarily need to extend to the upstream end of the intake port 46 as shown in FIG.

The center side of the intake ports 46A, 46B
The cross-sectional area of the passage 4 and the side passage 5 depends on the operating state of the engine.
It is configured to be constant irrespective of this. That is,
In the central passage 4 and the side passage 5, there are passage cross sections of control valves and the like.
There is no mechanism to change the product,
So that the flow path resistance in the ports 46A and 46B is as small as possible.
Is configured. This is provided with a control valve etc.
And the control valve itself becomes flow resistance, and the flow coefficient decreases.
This is because the intake ports 46A, 4
In order to minimize the flow path resistance in 6B, such a control valve
And the like are omitted. By the way, the injector 12 as the above-described fuel injection means is disposed at an upper portion near the branch portion 46C of the two intake ports 46A and 46B as shown in FIGS. Further, the injector 12 is disposed along a reference plane (center plane) 3 of the intake flow between the two intake ports 46A and 46B.
The fuel is injected toward the lower surface downstream of the intake ports 46A and 46B. Reference numeral 6 in FIGS. 2, 3, and 5 denotes an injector injection axis, which indicates the injection direction of the injector 12.

That is, as shown by the injector injection axis 6, the injector 12 is connected to the intake ports 46A, 4A.
Fuel is injected downward from the upper side between 6B and downstream of the intake ports 46A and 46B. The fuel injected downward is supplied to the intake ports 46A,
The partition walls 21 and 21 provided in the intake port 46B allow air to be taken into the combustion chamber 30 through the central passage 4 in the intake ports 46A and 46B. , Only air flows.

As the injection variations of the injector 12, types shown in FIGS. 6A to 6D can be considered. (A) injects fuel toward the branch 46C of the siamese type intake ports 46A and 46B.
After the fuel is positively collided with the fuel, the diffused fuel is caused to flow to the center side passage 4 in the intake ports 46A and 46B. Branch portion 4 of intake ports 46A, 46B
6C has a surface that is substantially orthogonal to the injection direction of the injector 12, and diffuses fuel that has collided with this surface.

Next, (b) shows a type in which an injector 12 having two fuel injection holes is used. The flow of the two fuels injected from each fuel injection hole is determined by each of the intake ports 46A and 46B. , And flows directly into the central side passage 4. In this case, the intake port 46A,
The branch portion 46C of 46B is formed in a curved surface shape to reduce the intake resistance of the intake flow.

As shown in (c), the fuel is directly injected into the center side passage 4 using the injector 12 having one fuel injection hole so that the fuel does not adhere to the partition walls 21 and 21. Such a type is also conceivable. In this case, the branch portion 46C of the intake ports 46A and 46B is formed at an acute angle so that the fuel is smoothly taken in along with the intake.

In addition, (d) is of the type in which the fuel is actively injected toward the wide angle up to the partition walls 21 and 21, contrary to the above (c). In this case, the branch portion 46C of the intake ports 46A and 46B is rounded in a curved shape as in the above (b) in order to reduce the resistance. In this embodiment, any of the above-described injection variations is used.

The above (a) to (d) show the injection variations of the injector 12, and the arrangement position of the injector 12 and the injection axis 6 are all the same. Since the intake port structure of the internal combustion engine as the first embodiment of the present invention is configured as described above, the intake air is mixed with the fuel injected by the injector 12, and the intake ports 46A and 46B are mixed. , Flows into the combustion chamber 30, is compressed and expanded (exploded) in the combustion chamber 30, and is then discharged from the exhaust ports 47 </ b> A and 47 </ b> B.

Further, in each of the intake ports 46A and 46B, the intake flow components from the tumble flow side halves 46A-1 and 46B-1 are more than the intake flow components from the other halves 46A-2 and 46B-2. Significantly stronger. That is, the intake port 4
6A, 46B tumble flow side half 46A-1, 46B-
The intake flow component from 1 is a flow component forming a tumble flow, and the other half 46A- of the intake ports 46A and 46B.
The intake air flow components from the intake ports 46A and 46B-2 are components that block the tumble flow. Therefore, due to the above-described flow rate imbalance, the overall flow path cross-sectional area of the intake ports 46A and 46B is not reduced.
In other words, it is possible to increase the strength of the tumble flow while keeping the flow rate (flow velocity) of the intake flow in the entire intake port constant.

At this time, at the time of intake, the intake port 46
Only air is sent to the outer passage 5 partitioned by the partition wall 21 of A, 46B, while fuel is supplied to the intake ports 46A, 4B.
Since the fuel and the air are sent only to the central side passage 4 partitioned by the partition 21 of 6B, the fuel and the air are stratified, and as shown in FIG. An air layer Fa is formed on both sides thereof.

This is because the intake ports 46A, 46B and the partition 21 provided therein are disposed substantially in parallel, and as shown in FIG.
A layer Fm of the air-fuel mixture flowing into the combustion chamber 30 from the central passage 4 of B and a layer Fa of air flowing into the combustion chamber 30 from the side passage 5 partitioned by the partition 21 are separated even in the combustion chamber 30. , It is stratified.

Thus, even if an air-fuel mixture containing less fuel is sent to the entire combustion chamber 30, a sufficient amount of fuel for ignition is sent to the vicinity of the ignition plug 11. Since the fuel-fuel mixture flows near the ignition plug 11, the engine can be operated with a fuel mixture having a smaller amount than the stoichiometric air-fuel ratio without deteriorating the ignitability. Also,
By promoting the stratification of the intake air flow in this manner, the formation of the tumble flow in the combustion chamber 30 is also enhanced. In other words, the intake air flow is branched into the central side passage 4 and the side passage 5 of each of the intake ports 46A and 46B, and the branched intake air flows into the combustion chamber 30 while maintaining a parallel state.
The intake flow is rectified, and a tumble flow is easily formed. That is, a layer of the air-fuel mixture formed in the combustion chamber 30
Three layers consisting of Fm and air layers Fa on both sides of Fm
As shown in Fig. 1, the tumble flow of
As they rotate around an axis perpendicular to the central axis, they collide with each other.
And the filling efficiency is improved.

Further, as shown in the graph of FIG. 7, by providing the partition walls 21 at the intake ports 46A and 46B to promote stratification of the air-fuel mixture, the engine can be operated with a leaner air-fuel mixture. Here, the horizontal axis of the graph in FIG. 7 is the air-fuel ratio (A / F), and the vertical axis is the NOx emission amount and Pi (illustrated average effective pressure) fluctuation rate. Line a and line c are
This shows the characteristics of the engine in which the partition 21 is provided at the intake port, and the line b
The line d shows the characteristics of the engine having the normal tumble flow intake port without the partition 21. Lines a and b relate to NOx emission, and lines c and d relate to the Pi fluctuation rate.

First, the line a and the line b show the relationship between the A / F and the NOx emission amount. As shown in this figure, in the engine provided with the partition 21 (see the line a), The NOx emission peaks on the lean (thinner) side of the A / F value as compared to the engine using the normal tumble flow (see line b). The lines c and d show the relationship between the A / F and the Pi fluctuation rate. Here, the Pi fluctuation rate is a measure for judging the combustion stability of the engine. If the Pi fluctuation rate is too low, the combustion of the engine is not stabilized, and an uncomfortable operation state accompanied by a torque fluctuation is caused. . In addition, the reference line e in the figure is a Pi fluctuation rate of the combustion stability limit that can be operated without any discomfort.

As shown in this figure, the engine provided with the partition 21 (see the line c) uses a normal tumble flow against the limit value of the Pi fluctuation rate at which a stable combustion state in the cylinder is obtained. A / on the leaner side than the institution (see line d)
The engine can be operated at F, and the emission of NOx at this time can also be significantly reduced. In other words, it shows that a stable combustion state can be obtained even with a leaner A / F, and the A / F at the combustion limit can be improved.

Therefore, an engine which has extremely low fuel consumption and hardly emits NOx can be realized by this structure. Also, as shown in FIGS. 8 and 9, the upper half portions 46A-1 and 46B-1 of the substantially inverted triangular cross sections of the intake ports 46A and 46B are sufficiently large to secure a flow coefficient when the engine is fully opened. can do.

FIG. 8 shows the relationship between the port cross-sectional area and the average tumble ratio and average flow coefficient. Here, the line a shows the relationship between the port cross-sectional area and the average tumble ratio, and the line b shows the relationship between the port cross-sectional area and the average flow coefficient. 8 indicate the average tumble ratio of the engine having the normal tumble flow intake port, and the Δ marks indicate the upper half portions 46A-1 and 46B- of the cross sections of the intake ports 46A and 46B. 1 shows the average tumble ratio of an engine having an intake port sufficiently large.

○ indicates the average flow coefficient of the engine having the normal tumble flow intake port.
Is the upper half 46A of the cross section of the intake ports 46A and 46B.
It shows the average flow coefficient of an engine having an intake port having a sufficiently large value of 1,46B-1. In the intake ports 46A and 46B of the present invention, the upper half 46A-
1, 46B-1 is made sufficiently large to secure the port cross-sectional area, so that the average tumble ratio,
Both average flow coefficient can be improved.

As a result, the relationship between the tumble ratio and the flow coefficient is as shown in FIG. In FIG. 9, the mark “△” indicates an engine using a conventional tumble flow, and the mark “☆” indicates that the partition 21 is provided.
6A and 46B, the cross-sectional area of the engine is reduced, and ★ indicates the engine having this structure, and the intake ports 46A and 46B
The upper half portions 46A-1 and 46B-1 of the cross section of FIG.

That is, as shown in FIG. 9, simply providing the partition 21 at the intake ports 46A and 46B will reduce the flow coefficient even if the stratification of the intake air flow is promoted, and it is considered that the full opening performance is reduced. Can be Here, as shown by the ★ mark,
Upper half 46A of the cross section of the intake ports 46A, 46B-
By making 1,46B-1 sufficiently large, the tumble ratio and the flow coefficient can be improved. Therefore, the intake ports 46A, 4
The decrease in the cross-sectional area of 6B can be compensated for, and the fully open performance of the engine can be ensured.

FIG. 10 shows the rotational speed, the torque and the output of the engine. In the figure, lines a and c are graphs showing the characteristics of the engine having this structure, lines b and d.
Is a graph showing characteristics of an engine having a conventional intake port structure. First, the lines a and b show the relationship between the rotational speed and the torque of the engine. There is almost no difference between the two curves, and the engine equipped with this structure is operated with a leaner mixture than before. This shows that torque equivalent to that of a conventional engine is realized.

Lines c and d show the relationship between the rotational speed of the engine and the output.
As with the torque characteristics described above, there is almost no difference between the two, indicating that the engine and the conventional engine can obtain an output even when operated with a leaner air-fuel mixture. Therefore, as shown in FIG. 10, the engine having the present structure can increase the tumble ratio and the flow coefficient of the intake ports 46A and 46B so that the partition walls 21 and 21 are provided in the intake ports 46A and 46B. Thus, an internal combustion engine having the same torque and output characteristics as those of the other engines can be realized.

As described above, the partition walls 21, 21 are provided in the intake ports 46A, 46B, and the intake ports 46A, 46
Upper half portions 46A-1 and 46B of a substantially inverted triangular cross section of 6B
By making -1 sufficiently large, it is possible to maintain a stable combustion state with a mixture leaner than the conventional internal combustion engine without lowering the torque and the output as compared with the conventional internal combustion engine, and reduce NOx. be able to. At the same time, fuel efficiency can be improved.

Further, as shown in FIG. 3, by forming the downstream end of the partition 21 upstream of the axis 2 of the intake valve 58, the manufacturing process can be simplified and the manufacturing cost can be reduced. It can be kept low. The first embodiment can be similarly applied to a three-valve internal combustion engine having two intake ports 46A and 46B and one exhaust port 47.

Next, a description will be given of an intake port structure of an internal combustion engine according to a second embodiment of the present invention. FIG. 11 is a schematic partial sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). The second embodiment is different from the first embodiment only in the shape of the partition wall 21, and the other structure is the same as that of the first embodiment.

In the second embodiment, as shown in FIG. 11, the partition 21A is formed from the upper inner wall 8 to the lower inner wall 7 of the intake ports 46A and 46B.
In particular, a partition 21B is also provided at the tip of the stem 57 of the intake valve 58 in the intake ports 46A and 46B. Thereby, the center side passage 4 and the side passage 5 are completely separated. The valve stem 57 of the intake valve 58 is provided to penetrate the partition walls 21A and 21B in the vertical direction.

As a result, the flow of the intake air branched into the center side passage 4 and the side passage 5 in the intake ports 46A and 46B is completely separated until the air flows from the intake valve 58 into the combustion chamber 30. Is kept. Due to such partition walls 21A and 21B, this flow is generated by the combustion chamber 3
0, the air-fuel mixture layer Fm and the air layers Fa, F
a (the center passage 4 and the side passages 5 on both sides thereof)
(A total of three flows), that is, a layered state can be maintained. Therefore, the present internal combustion engine is configured as a stratified combustion internal combustion engine.

Since the intake port structure of the internal combustion engine according to the second embodiment of the present invention is constructed as described above, the same effects as those of the first embodiment can be obtained. Layering can be further promoted. That is,
With a simple configuration in which a partition 21B is added to the tip of the stem portion 57 of the intake valve 58 along the extension of the partition 21A, the intake flow branched in the intake ports 46A and 46B is completely separated, and the combustion chamber is separated. The stratification of the air-fuel mixture can be realized more reliably in the inside 30. Thus, the lean air-fuel mixture can be reliably burned.

Next, an intake port structure of an internal combustion engine according to a third embodiment of the present invention will be described. FIG. 12 is a schematic partial cross-sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). In the third embodiment, as in the second embodiment,
Only the shape of the partition walls 21 and 21 in the above-described first embodiment is different, and the other structure is the same as that of the above-described first and second embodiments. This internal combustion engine is also configured as a stratified combustion internal combustion engine.

In this embodiment, as shown in FIG. 12, the partition 21C is formed on the lower half side of the intake ports 46A and 46B in parallel with each other, and only this lower half is vertically bisected. It has become. Therefore, in the upper half of each of the intake ports 46A and 46B, the center passage 4 and the side passage 5 are not partitioned, and the two passages 4 and 5 are formed as one passage.

Since the intake port structure of the internal combustion engine according to the third embodiment of the present invention is constructed as described above, the same effects as those of the first embodiment can be obtained. As in the example, the manufacturing cost can be reduced.
That is, in the present embodiment, as described in the first embodiment,
The injector 12 is disposed above the intake passage near the branch 46C between the two intake ports 46A and 46B, and injects fuel from the upper side of the intake passage downward of the intake ports 46A and 46B. Since the partition 21C provided in the intake ports 46A and 46B partitions only the lower half, the intake can be sufficiently stratified. In the partition 21C of the third embodiment, the manufacturing cost of the upper half can be reduced by omitting the upper half of the partition 21 of the second embodiment, and the intake ports 46A and 46B. Weight can be reduced.

Next, the structure of an intake port of an internal combustion engine according to a fourth embodiment of the present invention will be described. FIG. 13 is a schematic partial sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). This internal combustion engine is also configured as a stratified combustion internal combustion engine. The partition 21D in the fourth embodiment is also the first partition.
Like the embodiment, the intake ports 46A, 46B are formed in parallel from the upper surface side inner wall 8 to the lower surface side inner wall 7, and are provided so as to bisect the intake ports 46A, 46B in the left-right direction. And these partition walls 21D, 21D
Accordingly, the inside of each intake port 46A, 46B is divided into a spark plug side (center side) passage 4 and a non-spark plug side (outside) passage 5 along the flow direction of intake air.

Then, as shown in FIG.
1D extends from the upstream side of the intake ports 46A and 46B to a position just before the umbrella portion 56 of the intake valve 58, and is formed by omitting a portion near the umbrella portion 56 from the partition 21B of the second embodiment. Have been. Since the intake port structure of the internal combustion engine as the fourth embodiment of the present invention is configured as described above, the same effects as those of the first embodiment can be obtained, and the number of manufacturing steps can be reduced. Can be. That is, the partition 2
By omitting the portion of the intake valve 58 near the umbrella portion 56 of the intake valve 58, the intake ports 46A and 46B can be formed without requiring a highly accurate manufacturing technique.

Next, the structure of an intake port of an internal combustion engine according to a fifth embodiment of the present invention will be described. FIG. 14 is a schematic partial cross-sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). This internal combustion engine is also configured as a stratified combustion internal combustion engine. The partition 21E according to the fifth embodiment is provided in the same manner as the partition 21D according to the fourth embodiment except that a portion near the stem 57 of the intake valve 58 is omitted. That is, as shown in the figure, the end of the partition 21E is connected to the stem 5 of the intake valve 58.
7, and the end of the partition 21E is formed in a straight line. In addition, this intake valve 5
If the gap between the stem portion 57 of FIG. 8 and the end of the partition wall 21E is too large, the flow of the intake air in the intake ports 46A and 46B may be disturbed. Therefore, the gap is provided so as not to be too large. I have.

Since the intake port structure of the internal combustion engine according to the fifth embodiment of the present invention is configured as described above, the same effects as those of the first embodiment can be obtained.
Since the shape of the partition 21E is also simple, the manufacturing cost and the number of steps can be reduced. Next, an intake port structure of an internal combustion engine as a sixth embodiment of the present invention will be described. FIGS. 15 to 21 show an intake port structure of an internal combustion engine as a sixth embodiment of the present invention. 16 is a schematic partial longitudinal sectional view thereof, FIG. 17 is a schematic sectional view of a surface orthogonal to the flow direction, and FIGS. 18 to 20 are sectional shapes of surfaces orthogonal to the flow direction, respectively. FIG. 2 is a schematic cross-sectional view showing various examples of FIG.
FIG. 1 is a schematic plan view showing a modification example corresponding to FIG.

The internal combustion engine is also configured as a stratified combustion internal combustion engine. As shown in FIGS. 15 and 16, each cylinder of the internal combustion engine having the intake port structure according to the first embodiment has a cylinder bore 24, a piston 26, and a cylinder head 2 formed in a cylinder block 22.
8 to form a combustion chamber 30 and the combustion chamber 3
The two intake ports 46A and 46B are guided inside the cylinder 0, and the intake valves 58 are respectively installed. In addition, two exhaust ports 47A and 47B are also guided into the combustion chamber 30, and exhaust valves are provided respectively.

The intake ports 46A and 46B join at the upstream side and are connected to the common intake passage 43, and the exhaust ports 47A and 47B join at the downstream side and communicate with the common exhaust passage 60. It is connected. A spark plug 1 as an ignition means is provided at the center of the cylinder 25.
1 is located between the intake ports 46A and 46B.

Further, a pent roof 34 is formed on the upper wall portion of the combustion chamber 30.
The intake port 46A, 46B is provided with a slope which can guide the intake air flow downward along the inner wall surface of the cylinder bore 24 on the extension axis of each intake port 46A, 46B. The guidance of the pent roof 34 also promotes the generation of the tumble flow.

Further, each intake port 46 of this internal combustion engine
A and 46B are formed in a straight straight port as shown in FIG. 16, and the cross-sectional shape of the straight port is, as shown in FIG.
The tumble flow side halves of A and 46B (that is, the upper halves of the intake ports 46A and 46B through which the main component flow forming the tumble flow flows) 46A-1 and 46B-1 block the other half (that is, the tumble flow). Port 4 through which such component flows
6A, 46B, which are wider than the lower halves 46A-2, 46B-2, so that the intake convergence of the intake ports 46A, 46B is on the tumble flow side (that is, the upper half 46A-1 of the intake ports 46A, 46B). , 46B-1).
Thus, the intake air flows from the intake ports 46A and 46B easily form a tumble flow in the combustion chamber 30.

In the sixth embodiment, the intake ports 46A and 46B are formed to have a substantially inverted triangular cross section. A partition 21 is provided in each of the intake ports 46A and 46B so as to bisect the intake ports 46A and 46B in the left-right direction. ) And the anti-spark plug side (outside) along the flow direction of the air-fuel mixture.

An injector 12 as a fuel injection means is mounted near the junction of the intake ports 46A and 46B, and the injector 12 is connected to the intake ports 46A and 46B.
The fuel is sent to the center side partitioned by the partition wall 21 of 46B (see FIGS. 15 and 17). In addition, the intake valve 5
The eighth valve stem 57 penetrates the partition 21 in the vertical direction.

Also, the intake port 46A with the partition 21 is provided.
46B, its tumble flow side half 46A-1,4
The cross-sectional shape of 6B-1 to be wider than the other halves 46A-2 and 46B-2 is, as shown in FIG. 17, a baseball home base shape as shown in FIG. 19, the other half 46A-2, 4 as shown in FIG.
20B-2 having a round shape and a tongue shape.
As shown in FIG. 5, various types of intake ports, each of which is partitioned by a partition 21 and formed into a baseball home base shape, can be considered.

With this configuration, the intake air is mixed with the fuel injected by the injector 12 and
A and 46B flow into the combustion chamber 30 and this air-fuel mixture is compressed and expanded (exploded) in the combustion chamber 30 and then discharged from each of the exhaust ports 47A and 47B to the exhaust passage 60. Only the air is sent to the outside of the intake ports 46A and 46B partitioned by the partition 21, and the fuel is sent only to the central side partitioned by the partition 21 of the intake ports 46A and 46B. The ignition plug 11 is supplied with an air-fuel mixture in a rich fuel layer. For this reason, an air-fuel mixture containing less fuel is sent to the entire combustion chamber 30,
A sufficient amount of fuel is supplied to the ignition plug 11 for ignition.
Therefore, since a location where fuel is rich can be formed near the ignition plug 11, the engine can be operated with a fuel mixture of an amount smaller than the stoichiometric air-fuel ratio without deteriorating ignitability.

Further, the intake flow components from the tumble flow-side halves 46A-1 and 46B-1 of the intake ports 46A and 46B are much larger than the intake flow components from the other halves 46A-2 and 46B-2. Become stronger. That is, the intake ports 46A, 4
The intake flow components from the tumble flow side halves 46A-1 and 46B-1 of 6B are the components of the flow forming the tumble flow,
The other half 46A-2, 46B of the intake ports 46A, 46B
Since the intake flow component from -2 is a component that prevents the tumble flow, the above-described flow rate imbalance does not reduce the cross-sectional area of the entire flow passage of the intake port. This makes it possible to increase the strength of the tumble flow while keeping the flow rate (flow velocity) constant.

In the sixth embodiment, as shown in FIG. 21, two intake ports 46A and 46B and two exhaust ports
7 can be similarly applied to a three-valve internal combustion engine having one.

[0074]

As described in detail above, according to the intake port structure of the internal combustion engine of the present invention, the intake port having two combustion chamber openings opened and closed by two intake valves is provided. In addition, in an internal combustion engine configured such that the intake flow from the intake port becomes a tumble flow in the combustion chamber, an ignition means disposed at a central portion of the top of the combustion chamber; and a lower surface side in the intake port. Two partition walls extending on the inner wall along the direction of the intake stream line, and partitioning the intake port into a central passage on the side of the ignition means and side passages on both sides thereof; arranged near a fuel injection means for injecting fuel toward the lower side of the central side passage is provided in the intake port, the intake
The passage cross-sectional area of the central passage and the side passage of the port is
In this configuration, the air-fuel mixture in the intake port and the air (or lean
Aeration) can be separated from the flow, and the tumble flow of the air-fuel mixture layer is formed on the ignition means side at the center of the top of the combustion chamber, and the tumble flow of the air-only layer is formed on the anti-ignition means side be able to. As a result, a stable combustion state can be obtained even with a lean mixture, and an extremely fuel-efficient internal combustion engine can be realized. In the combustion chamber,
A laminar tumbler consisting of a tumble flow of air on both sides
Flow is formed, but these three tumble flows are
The displacement also turns in layers around an axis perpendicular to the cylinder center axis.
Therefore, filling efficiency is improved without collision with each other
There is an advantage. Further, according to the present invention, the intake port
The control valve for changing the cross-sectional area of the flow path is
Determine the cross-sectional area of the central side passage and side passage of the air port by the engine.
By making the configuration constant regardless of the operation state, the intake port
The flow resistance in the port is minimized and the flow coefficient is improved.
It also has the advantage of In addition, the above
Since no control valve is used, the control valve itself and the opening of the control valve
No mechanism for adjusting the pressure is required, and the cost is reduced.
There are advantages that can be.

Further, if the partition extends from the lower inner wall of the intake port to the upper inner wall of the intake port, the flow of the air-fuel mixture in the intake port and the air are increased. Of the mixture can be completely separated, and the stratification of the air-fuel mixture layer and the air-only layer can be enhanced. Further, even when a space is provided between the partition and the inner wall on the upper surface of the intake port, the flow of the air-fuel mixture in the intake port and the flow of air are separated. And the weight of the intake port can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an intake port structure of an internal combustion engine as a first embodiment of the present invention.

FIG. 2 is a schematic top view showing a configuration of an intake port structure of the internal combustion engine as a first embodiment of the present invention, and is a view as seen from an arrow A in FIG.

FIG. 3 is a schematic partial sectional view showing a configuration of an intake port structure of an internal combustion engine as a first embodiment of the present invention, and FIG.
10 is a sectional view taken along line CC in FIG.

FIG. 4 is a schematic partial cross-sectional view showing a configuration of an intake port structure of an internal combustion engine as a first embodiment of the present invention, and FIG.
It is BB sectional drawing in.

FIG. 5 is a schematic view showing the operation of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 6 is a schematic view showing a variation of a fuel injection method in an intake port structure of an internal combustion engine as a first embodiment of the present invention.

FIG. 7 is a graph showing the effect of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 8 is a graph showing the effect of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 9 is a graph showing the effect of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 10 is a graph showing the effect of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 11 is a schematic partial sectional view showing a configuration of an intake port structure of an internal combustion engine as a second embodiment of the present invention, which is shown in FIG. 3 (a sectional view taken along line CC in FIG. 2) in the first embodiment; Corresponding figure

FIG. 12 is a schematic partial sectional view showing a configuration of an intake port structure of an internal combustion engine as a third embodiment of the present invention, which is shown in FIG. 3 (a sectional view taken along line CC in FIG. 2) in the first embodiment; It is a corresponding figure.

FIG. 13 is a schematic partial sectional view showing a configuration of an intake port structure of an internal combustion engine as a fourth embodiment of the present invention, which is shown in FIG. 3 (a sectional view taken along line CC in FIG. 2) in the first embodiment. It is a corresponding figure.

FIG. 14 is a schematic partial sectional view showing a configuration of an intake port structure of an internal combustion engine as a fifth embodiment of the present invention, which is shown in FIG. 3 (a sectional view taken along line CC in FIG. 2) of the first embodiment; It is a corresponding figure.

FIG. 15 is a schematic plan view of an intake port structure of an internal combustion engine as a sixth embodiment of the present invention.

FIG. 16 is a schematic partial longitudinal sectional view of an intake port structure of an internal combustion engine as a sixth embodiment of the present invention.

FIG. 17 is a schematic sectional view of a plane orthogonal to a flow direction of an intake port structure of an internal combustion engine as a sixth embodiment of the present invention.

FIG. 18 is a schematic sectional view corresponding to FIG. 3, showing another example of a sectional shape of a surface orthogonal to the flow direction in an intake port structure of an internal combustion engine as a sixth embodiment of the present invention.

FIG. 19 is a schematic sectional view showing another example of a sectional shape of a surface orthogonal to the flow direction in an intake port structure of an internal combustion engine as a sixth embodiment of the present invention, corresponding to FIG.

20 is a schematic cross-sectional view showing another example of the cross-sectional shape of a surface orthogonal to the flow direction in the intake port structure of the internal combustion engine as the sixth embodiment of the present invention, corresponding to FIG.

FIG. 21 is a schematic plan view showing a modification of the intake port structure of the internal combustion engine as the sixth embodiment of the present invention, corresponding to FIG.

FIG. 22 is a schematic longitudinal sectional view showing a conventional intake port structure of an internal combustion engine together with around a combustion chamber.

FIG. 23 is a schematic perspective view showing a conventional intake port structure of an internal combustion engine together with around a combustion chamber.

24 is a schematic cross-sectional view of a surface of the conventional intake port structure of an internal combustion engine, which is perpendicular to the flow direction of intake air (D-D in FIG. 22).
FIG.

FIG. 25 is a cross-sectional view (a view corresponding to a cross section taken along the line DD in FIG. 22) showing another example of a schematic cross section of a surface of the conventional intake port structure of the conventional internal combustion engine, which is perpendicular to the flow direction of the intake air. is there.

FIG. 26 is a schematic longitudinal sectional view showing another example of a conventional intake port structure of an internal combustion engine.

FIG. 27 is a graph showing an effect of a tumble flow in an internal combustion engine using a conventional tumble flow.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A, 1B Intake port axis 2 Intake valve axis 3 Intake port reference plane 4 Center side passage 5 Side passage 6 Injector injection axis 7 Intake port lower side inner wall 8 Intake port upper side inner wall 11 Ignition plug as ignition means 12 Fuel Injector 13 as injection means 13 Intake port oblique portion 21, 21A to 21E Partition wall 22 Cylinder block 24 Cylinder bore 25 Cylinder 26 Piston 28 Cylinder head 30 Combustion chamber 34 Pent roof 35 Recess 37 Slope 39 Raised portion 46, 44 ', 40F, 42F Intake Ports 40 ', 42', 46A, 46B Intake port portion 46A-1, 46B-1 Upper half of intake port 46A-2, 46B-2 Lower half of intake port 46C Port partition or port branch 47 Exhaust Port 47A, 47B Exhaust port 5 6 Valve head 57 Valve stem 58 Intake valve 59 Exhaust valve 60 Exhaust passage Fa Tumble flow of air Fm Tumble flow of mixture F1 Flow core in intake port

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuki Tamura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Michihiro Hata 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Shunsuke Matsuo 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP-A-60-147537 (JP, A) JP-A Showa 60-233314 (JP, A) Actually open Showa 63-71423 (JP, U)

Claims (3)

(57) [Claims] An internal combustion engine having an intake port having two combustion chamber openings opened and closed by two intake valves, respectively, and configured so that an intake flow from the intake port becomes a tumble flow in the combustion chamber. An ignition means disposed at a central portion of a top portion of the combustion chamber, and extending along an intake stream line direction on an inner wall on a lower surface side in the intake port, and a center of the ignition port on the side of the ignition means. Two partition walls partitioning into a side passage and side passages on both sides thereof; a fuel disposed at or near an upper surface of the intake port, for injecting fuel downward in the intake port below the central passage. and injection means are provided, the passage cross section of the center side passage and said side lateral passages of the intake port
An intake port structure for an internal combustion engine, wherein a product is configured to be constant regardless of an engine operating state . 2. The intake port structure for an internal combustion engine according to claim 1, wherein the partition wall extends from a lower inner wall of the intake port to an upper inner wall. 3. The intake port structure for an internal combustion engine according to claim 1, wherein a space is provided between the partition and the inner wall on the upper surface of the intake port.