JP2697514B2 - Intake port structure of stratified combustion 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 a stratified combustion internal combustion engine, and more particularly, to a combustion system in which intake air from an intake port having two combustion chamber openings opened and closed by two intake valves is burned. The present invention relates to an intake port structure of a stratified combustion internal combustion engine configured to have a tumble flow stratified in a room.

[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).

[0003] 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. 21 and 22 show the structure of one cylinder of a two-intake-port internal combustion engine which generates the tumble flows Fa and Fm. In the drawings, reference numeral 22 denotes a cylinder block, reference numeral 24 denotes a cylinder bore, and reference numeral 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 intake flow from each intake port portion 40 ', 42' is provided with a slope which can be guided downward along the inner wall surface of the cylinder bore 24 on the extension axis of 2 '.
With the help of the guidance of No. 4, the vehicle travels in the tumble flow direction 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.
1, the intake port 44 'is formed as a straight straight port as shown in FIG. 22, or the intake port 44' is throttled as shown in FIG. 25 to rectify the flow. . In FIGS. 21 and 25, reference numerals 40F and 42F indicate normal intake ports that are not straight ports.

The cross section of the intake port 44 'is generally formed in a circular shape as shown in FIG. 23, 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. 22, the injector 12 is provided only on one intake port portion 42 ', and the ignition plug 11 is disposed near the intake valve 58 of the intake port portion 42' equipped with the injector 12. . Therefore, in the vicinity of the ignition plug 11, a mixture of fuel injected from the injector 12 and intake air flows into the combustion chamber 30 through the intake port portion 42 'and the intake port 44'. Is formed. Also, from the intake port 44 'of the intake port portion 40',
Only air flows into the combustion chamber 30 to form a tumble flow Fa of the air.

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 generated in this way is effective in increasing the flame propagation speed and combustion stability. Experimental data on the heat generation amount Q, the in-cylinder pressure P, and the heat generation rate dQ are shown in FIG. 26, for example. When the tumble flow is generated as compared with the standard (a general case where the tumble flow is not particularly generated), the cycle variation of the heat generation amount Q, the indicated average effective pressure P, and the heat generation rate dQ is smaller. It can be seen that 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 However, the two intake port portions 40 ', 4
2 'are arranged in parallel, both intake valves 58,
It is difficult to enrich only the central portion of the air-fuel mixture sucked in from 58, and there is a problem that the combustion state of the engine cannot be maintained in a stable state during lean combustion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and promotes stratification of a tumble flow of intake air in a cylinder while enriching an air-fuel ratio near a combustion ignition means at the center top of a combustion chamber. Provided is an intake port structure for a stratified combustion internal combustion engine, in which the air-fuel ratio of a tumble flow in the periphery of a chamber is reduced so that a stable lean-burn state can be maintained even with a fuel mixture having an amount smaller than the stoichiometric air-fuel ratio. With the goal.

[0011]

According to the present invention, there is provided an intake port structure for a stratified combustion internal combustion engine according to the present invention, wherein an 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, ignition means for combustion is provided at a central portion of the top of the combustion chamber, and the intake port Two partition walls are provided extending along the direction of the intake stream line, and bisect the interior of the intake port into a central passage on the ignition means side and side passages on both sides thereof. Fuel injection means for injecting fuel toward the side inner wall is provided at or near the lower surface side inner wall in the intake port, and the tumble flow is configured to be a stratified tumble flow having different fuel concentrations. It is characterized in that.

According to a second aspect of the present invention, there is provided an intake port structure for a stratified combustion internal combustion engine according to the present invention, in addition to the configuration of the first aspect, further comprising a space between the partition wall and an upper side inner wall in the intake port. Is provided. According to a third aspect of the present invention, in the intake port structure for a stratified combustion internal combustion engine of the present invention, in addition to the configuration of the first aspect, the partition wall extends from an upper inner wall to a lower inner wall of the intake port. It is characterized by being extended to.

According to a fourth aspect of the present invention, there is provided an intake port structure for a stratified combustion internal combustion engine having an intake port having two combustion chamber openings opened and closed by two intake valves, respectively. In an internal combustion engine configured such that the intake air flows each become a tumble flow in the combustion chamber, ignition means for combustion is arranged at a central portion of the top of the combustion chamber, and the intake port is provided in the intake port. from the upper surface to the lower surface side, and by an auxiliary partition wall which partitions the two partition walls extending along the intake flow line direction, connecting the lower end portions of both the partition walls of the intake port in the vertical direction, the intake ports
Enclosed by the inner wall on the upper surface side of the
Which is partitioned into a counter-ignition means side than the ignition means side and 該着fire means side, and, a fuel supply means for supplying fuel provided該着fire means side, tumble layered the tumble flow different fuel concentration It is characterized by being configured to flow.

[0014]

In the intake port structure for a stratified combustion 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. , A tumble flow is formed. At this time,
In the intake port, the partition divides the internal intake air into a central passage on the ignition means side and side passages on both sides thereof.
Further, the fuel is injected upward from the lower surface side of the central passage by the fuel injection means and mixed with the intake air flow.

Since 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, 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.

In the case where a space is provided between the partition and the inner wall on the upper surface side in the intake port, as in the case of the intake port structure of the stratified combustion internal combustion engine according to the present invention, the partition is also provided. Accordingly, the tumble flow between the air-fuel mixture layer and the air layer is stratified in the combustion chamber, and the flow outside the tumble flow near the ignition means is formed by the air-fuel mixture. As a result, the mixture is ignited reliably, and a stable combustion state is achieved.

Further, as in the intake port structure for a stratified combustion internal combustion engine according to the present invention, the partition wall extends from the upper inner wall to the lower inner wall of the intake port. Also, the air-fuel mixture layer and the air layer are completely separated and flow into the combustion chamber. Further, in the intake port structure of the stratified combustion internal combustion engine according to the present invention, a partition extending from the upper surface to the lower surface side in the intake port, and an auxiliary partition connecting the lower ends of both partitions to vertically partition the inside of the intake port. By the above, the intake air flows between the upper inner wall in the intake port and the partition
And the auxiliary partition is divided into the vicinity of the ignition means side surrounded by the auxiliary partition and the anti-ignition means side of the surrounding area, and the air-fuel mixture is supplied only to the ignition means side. Done.

Further, the fuel is isolated by the auxiliary partition wall in the intake port, so that the fuel is prevented from flowing not only laterally in the intake port but also downward in the intake port. As a result, the air-fuel mixture of the flow on the outside of the tumble flow on the ignition means side gathers also in the vicinity of the ignition means side, so that the air-fuel mixture is reliably ignited.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a stratified combustion internal combustion engine according to the present invention; FIG.
1 shows an intake port structure of a stratified combustion internal combustion engine as a first embodiment of the present invention. FIG. 1 is a schematic perspective view showing the structure, and FIG. 2 is a schematic top view showing the structure. 1, FIG. 3 is a schematic partial cross-sectional view showing the configuration, and is a CC cross-sectional view in FIG. 2, and FIG. 4 is a schematic partial cross-sectional view showing the configuration. 6 is a sectional view taken along the line BB in FIG. 5, FIG.
(A) to (d) are schematic diagrams showing variations of the manner of fuel 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 port portions 47A and 47B are also guided into the combustion chamber 30, and exhaust valves (not shown) are provided.

Each intake port portion (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 each of the intake ports 46A and 46B, an injector 12 as a fuel injection means, which will be 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.

The axes 1A and 1B of the intake ports 46A and 46B are two straight lines parallel to each other, as shown in FIGS. 2, 3 and 5. 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 passage on the side of the ignition plug) 4 on the reference surface 3 side of the intake flow and a passage (side passages on both sides of the central passage) 5 outside the reference surface 3 are respectively provided. It is divided into two along the flow direction of the intake air.

As shown in FIGS. 2 and 3, the partition 21 is formed substantially vertically along the axis 1A, 1B of the intake port 46A, 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 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 central passage 4 and a side passage 5. Thus, the flow branched into the central passage 4 and the side passage 5 in the intake ports 46A and 46B is
The air flows into the combustion chamber 30 while being separated from each other while being rectified by the partition 21. Therefore, when the flow of the intake air flows into the combustion chamber 30 as shown in FIG. 5 by the partition 21, the air-fuel mixture layer Fm and the air-only layers Fa and Fa are mixed with air.
Are separated into three layers (a total of three flows of the central passage 4 and the side passages 5 on both sides thereof), that is, a tumble flow is formed in a layered state.

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.

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 coefficient. For this reason, the partition 21 is formed so as to be as thin as possible. Therefore, in this embodiment, as shown in FIG. 2, the thickness of the partition 21 is gradually made substantially equal to the diameter of the valve stem 57 as it approaches the valve stem 57. Thus, the flow of the intake air flow is not disturbed by the valve stem 57, and the intake air flows into the combustion chamber 30 smoothly.

FIG. 5 shows a modified example of the partition wall 21. In this way, the thickness of the partition wall 21 is formed as thin as possible on the upstream side of the valve stem 57, and gradually becomes smaller 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 modification shown in FIG. 5, the partition 2
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.

As shown in FIGS. 1 and 5, the injector 12 as the above-mentioned fuel injection means is disposed below the branch portion 46C of the two intake ports 46A and 46B. The injector 12 serves as a reference plane (center plane) of the intake air flow between the two intake ports 46A and 46B.
3, and the intake ports 46A, 46B
The fuel is injected toward the upper surface downstream of. Reference numeral 6 in FIGS. 3 and 5 indicates an injector injection axis, which indicates the injection direction of the injector 12.

That is, as shown by the injector injection axis 6 in FIGS.
6A, 46B, these intake ports 46A,
Fuel is injected obliquely upward on the downstream side of 46B. And the fuel injected diagonally upward is
Partition walls 21 and 21 provided at intake ports 46A and 46B
As a result, air is sucked into the combustion chamber 30 through the central passage 4 in the intake ports 46A and 46B, and only air flows through the side passages 5 on both sides of the ignition plug. .

Since the fuel is injected along the injector injection axis 6 toward the inner wall 8 on the upper surface side, in the tumble flow Fm of the air-fuel mixture formed near the ignition plug 11, the fuel tumble flow Fm The flow outside the vicinity of the spark plug 11 becomes richer than the flow, and the ignition is reliably ignited in the combustion chamber 30. In addition, as the injection variation of the injector 12, types shown in FIGS.

(A) is a siamese type intake port 46.
A fuel is injected toward the branch portion 46C of each of the intake ports 46A and 46B.
It is made to flow to. This intake port 46A,
The branch portion 46C of 46B 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 using an injector 12 having two fuel injection holes, and 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 FIG. 3C, the fuel is directly injected into the central passage 4 by 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.

(D) is of the type in which the fuel is actively injected toward the wide angle up to each of 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 stratified combustion 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 is supplied from each intake port 46A, 46B to the combustion chamber 3A.
After being introduced into the combustion chamber 30 and compressed / expanded (exploded) in the combustion chamber 30, the exhaust gas is discharged from each of the exhaust ports 47A and 47B.

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 smaller 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.

That is, since the intake ports 46A and 46B and the partition 21 provided therein are arranged substantially in parallel, as shown in FIG.
The layer Fm of the air-fuel mixture flowing into the combustion chamber 30 from the central passage 4 of B is separated from the layer Fa of air flowing into the combustion chamber 30 from the outer passage 5 partitioned by the partition 21 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.

Thus, even if an air-fuel mixture with a small amount of 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 on the center side of the combustion chamber 30. Therefore, the engine can be operated with a fuel mixture of an amount smaller than the stoichiometric air-fuel ratio without deteriorating the ignitability. Further, since the fuel is injected upward (in the direction of the upper side inner wall 8) along the injector injection axis 6 by the injector 12, the tumble flow Fm of the air-fuel mixture formed near the ignition plug 11 (see FIG. 1). Then, the flow outside the vicinity of the ignition plug 11 becomes richer than the flow inside the tumble flow Fm, whereby the air-fuel mixture is ignited reliably in the combustion chamber 30 and a stable lean combustion state is established. Can be kept.

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 high, combustion of the engine is not stabilized, and an uncomfortable operation state accompanied by 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 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, this structure makes it possible to realize an engine that has extremely low fuel consumption and hardly emits NOx. 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, the average tumble ratio, and the 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 provided with 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 walls 21 in 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, and 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 partitions 21 and 21 are provided at the intake ports 46A and 46B, and the intake ports 46A and 4B are provided.
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 only on the upstream side of the axis 2 of the intake valve 58, the manufacturing process can be simplified.
Manufacturing costs can also 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, an intake port structure of a stratified combustion internal combustion engine according to a second embodiment of the present invention will be described.
FIG. 3 is a schematic partial cross-sectional view showing the configuration and corresponds to FIG. 3 (a cross-sectional view taken along line CC in FIG. 2) in the first embodiment. 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. That is, similar to the first embodiment shown in FIGS. 3 and 5, the injector 12 is provided with the branch portion 4 of the two intake ports 46A and 46B.
Around 6C, it is arranged along the reference plane 3 of the intake air flow, and injects fuel downstream of the intake ports 46A, 46B. Moreover, as shown by the injector injection axis 6 in FIG. 3, the injector 12 is connected to the intake ports 4A from the lower side between the intake ports 46A and 46B.
Fuel is injected upward on the downstream side of 6A and 46B.

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. Thus, the central passage 4 and the side passage 5 are completely separated. Further, the valve stem 5 of the intake valve 58
7 is provided so as to penetrate the partition walls 21A and 21B in the vertical direction.

Thus, the flow of the intake air branched into the central passage 4 and the side passages 5 in the intake ports 46A and 46B is maintained until the air flows from the intake valve 58 into the combustion chamber 30.
They are kept completely separate. Due to the partition walls 21A and 21B, even after the flow flows into the combustion chamber 30, the three layers of the air-fuel mixture layer Fm and the air layers Fa and Fa (the central passage 4 and the side passages 5 on both sides thereof) are formed. (A total of three flows), that is, a layered state can be maintained.

Since the intake port structure of the stratified combustion 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. Stream stratification can be further promoted.
That is, the partition 21A is provided at the tip of the stem 57 of the intake valve 58.
With the simple configuration of adding the partition 21B along the extension of the above, the intake air flow branched in the intake ports 46A and 46B is completely separated, and the stratification of the air-fuel mixture in the combustion chamber 30 is more reliably realized. can do. Thus, the lean air-fuel mixture can be reliably burned.

Next, an intake port structure of a stratified combustion internal combustion engine as a third embodiment of the present invention will be described.
Is a schematic partial cross-sectional view showing the configuration thereof, and is a view corresponding to FIG. 3 (CC cross-sectional view in FIG. 2) of the first embodiment, and FIG. 13 is a schematic partial cross-sectional view showing the internal shape thereof. FIG. 13 is a sectional view taken along line EE in FIG. 12. Also in the third embodiment, as in the second embodiment, only the shapes of the partition walls 21 and 21 in the above-described first embodiment are different.
Other structures are the same as those in the first and second embodiments. That is, similar to the first embodiment shown in FIG. 3 and FIG.
Around the diverging portion 46C of the intake ports 46A and 46B, it is arranged along the reference plane 3 of the intake air flow, and injects fuel toward the downstream of the intake ports 46A and 46B. Moreover,
As shown by the injector injection axis 6 in FIG. 3, the injector 12 injects fuel upward from inside the intake ports 46A, 46B from the lower side between the intake ports 46A, 46B.

The partition 21C of the third embodiment is similar to that of FIG.
As shown in FIG. 13, the intake ports 46A and 46B are formed parallel to each other on the upper half side, and only the upper half is vertically bisected. Therefore, in the lower half of each intake port 46A, 46B, the central passage 4 and the side passage 5 are not partitioned, and these two passages 4, 5 are not divided.
Are formed as one passage.

That is, as shown in FIG. 3, since the fuel is injected upward along the injector injection axis 6, only the upper half of the intake ports 46A and 46B is partitioned. This stratifies the intake air flow. In the third embodiment, the partition 21
Configurations other than C are configured similarly to the first embodiment.

Since the intake port structure of the stratified combustion 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. The intake airflow can be sufficiently stratified while reducing the weight of the ports 46A and 46B. Further, in the present embodiment, similarly to the first embodiment, the injector 12 is disposed below the intake passage near the branch portion 46C of the two intake ports 46A and 46B, and extends from the lower surface side inner wall 7 of the intake passage to the intake port. Since the fuel is injected upward from above the intake ports 46A and 46B, the partition 21C is
By dividing only the upper half side in A and 46B into two, the intake air flow can be sufficiently stratified. The partition 21C of the third embodiment can reduce the manufacturing cost of the lower half by omitting the lower half of the partition 21 of the second embodiment, and further, the intake ports 46A and 46B. Weight can be reduced. Further, the intake port 46A,
It can also contribute to an increase in the flow coefficient within 46B.

Next, the structure of an intake port of a stratified combustion internal combustion engine according to a fourth embodiment of the present invention will be described with reference to FIG.
Is a schematic partial cross-sectional view showing the configuration thereof, corresponding to FIG. 3 (CC cross-sectional view in FIG. 2) in the first embodiment, and FIG. 15 is a schematic partial cross-sectional view showing the internal shape thereof. FIG. 15 is a sectional view taken along line FF in FIG. 14. This fourth
In the embodiment, the intake ports 46A, 46A of the first embodiment are described.
The structure in B is different, and the other structures are the same as those in the first embodiment.
It has the same configuration as the third to third embodiments. That is, the injector 12 is similar to the first embodiment shown in FIGS.
Around the branch portion 46C of the two intake ports 46A, 46B, it is arranged along the reference plane 3 of the intake flow, and is configured to inject fuel downstream of the intake ports 46A, 46B. Moreover, the injector injection axis 6 shown in FIG.
As shown in FIG.
A, 46B, from the lower side between these intake ports 46A, 4B.
The fuel is injected upward on the downstream side of 6B.

As shown in FIGS. 14 and 15, a partition 21C is provided in the intake port 46A, 46B in the vertical direction in the same manner as in the third embodiment.
A, 46B are bisected in the left-right direction. A substantially horizontal partition 21F as an auxiliary partition is provided along the lower side of the partition 21C so as to vertically divide the intake ports 46A, 46B into two. Therefore, this partition 2
1F, the upper half 4
6A-1, 46B-1 and lower half 46A-2, 46B-2
And the upper half 46A
-1, 46B-1 are divided into a center side (spark plug side) passage 4 and a side (anti-spark plug side) passage 5 by a partition 21C.

The substantially horizontal partition wall 21F extends downstream from the position where the injector 12 is provided.
As a result, the fuel injected from the injector 12 is supplied to the upper halves 46A-1, 46B in the intake ports 46A, 46B.
-1. Since the intake port structure of the stratified combustion internal combustion engine according to the fourth embodiment of the present invention is configured as described above, the fuel injected toward the upper inner wall 8 along the injector injection axis 6 is separated from the partition wall. 2
1F, the upper half side 46 of the intake ports 46A, 46B.
A-1 and 46B-1. The injected fuel is supplied to the upper half 46A-1, 46A by the partition 21C.
It flows into the central passage 4 of B-1.

Therefore, similarly to the first embodiment,
The fuel and air are stratified by the substantially vertical partition wall 21C. As shown in FIG. 1, a tumble flow Fm of the air-fuel mixture due to the air-fuel mixture flowing into the central passage 4 is formed near the ignition plug 11, and a tumble flow Fa due to the air flowing into the side passage 5 is formed on both sides thereof. Is formed. Further, only the air flows into the lower halves 46A-2, 46B-2 of the intake ports 46A, 46B by the substantially horizontal partition 21F, so that the outside of the tumble flow Fm of the air-fuel mixture is mixed from the central passage 4 The inside of the tumble flow is formed by air from the lower halves 46A-2 and 46B-2.

As a result, the mixture outside the tumble flow Fm of the mixture becomes a mixture having a high fuel concentration, which is concentrated near the spark plug 11. Thereby, the air-fuel mixture becomes 3 in the combustion chamber.
At 0, ignition and combustion can be ensured, and a stable combustion state can be obtained even with a fuel leaner than before. Next, an intake port structure of a stratified combustion internal combustion engine as a fifth embodiment of the present invention will be described. FIG. 16 is a schematic perspective view showing the structure, corresponding to FIG. 1, and FIG. FIG. 18 is a schematic partial cross-sectional view taken along the line XX in FIG. 16, and FIG. 18 is a schematic partial cross-sectional view taken along the line VV in FIG.

The fifth embodiment differs from the fourth embodiment in that the position of the injector 12 and the intake ports 46A,
Only the structure corresponding to the auxiliary partition 21F in 46B is different, and the other structure is the same as that of the above-described fourth embodiment. That is, in this embodiment, the intake port 4
A partition 21C is provided in the vertical direction in 6A, 46B, and divides the intake ports 46A, 46B into two in the left-right direction. A substantially horizontal partition 21G as an auxiliary partition is provided so as to connect the lower side of the partition 21C.

In the fifth embodiment, the injector 12 is connected to the branch 4 of the two intake ports 46A and 46B.
It is arranged in the upper part near 6C. The injector 12 is disposed along the reference plane 3 of the intake flow between the two intake ports 46A and 46B.
Numeral 2 injects fuel from a lower side between the intake ports 46A and 46B toward a lower side downstream of the intake ports 46A and 46B.

As shown in FIGS. 17 and 18, the upstream end of the auxiliary partition 21G is provided up to the vicinity of the position where the injector 12 is provided, similarly to the partition 21C in the vertical direction. The fuel injected from the injector 12 is prevented from diffusing downward in the intake port 46. In other words, on the upstream side of the branch portion 46C of the intake ports 46A, 46B, the intake ports 46A, 46B
For example, a central side passage 4 having a rectangular cross section as shown in FIG. 17 is provided at the upper part of the inside, and is bisected from the side passage 5. Further, on the downstream side of the branch portion 46C, the center side passage 4 is formed in an upper portion of each of the intake ports 46A and 46B on the reference surface 3 side.

Since the intake port structure of the stratified combustion internal combustion engine according to the fifth embodiment of the present invention is constructed as described above, the fuel injected downward to the intake ports 46A and 46B is supplied to the intake port. The horizontal partition 21G provided in 46A, 46B prevents the inflow to the side passage 5. And the injected fuel is the upper half 46A-1, 46A.
The air flows into the central passage 4 of B-1, and only air flows into the side passage 5.

Therefore, as in the first to fourth embodiments, the fuel and air are stratified by the substantially vertical partition 21C. As shown in FIG. 1, a tumble flow Fm of the air-fuel mixture due to the air-fuel mixture flowing into the central passage 4 is formed near the ignition plug 11, and a tumble flow Fa due to the air flowing into the side passage 5 is formed on both sides thereof. Is formed. Since the partition 21G extends from the upstream side to the downstream side from the position where the injector 12 is provided, the upper half portions 46A-1, 46B- of the intake ports 46A, 46B can be surely supplied with fuel.
1 into the central passage 4,
The outside of the tumble flow Fm near the ignition plug 11 is formed by the air-fuel mixture from the central passage 4, and the inside of the tumble flow is formed by air from the lower halves 46A-2, 46B-2 of the side passage 5. You.

Therefore, outside the tumble flow Fm of the air-fuel mixture, the air-fuel mixture having a high fuel concentration is concentrated near the spark plug 11. Thereby, the air-fuel mixture becomes 3 in the combustion chamber.
At 0, ignition and combustion can be ensured, and a stable combustion state can be obtained even with a fuel leaner than before. Next, an intake port structure of a stratified combustion internal combustion engine according to a sixth embodiment of the present invention will be described. FIG. 19 is a schematic partial cross-sectional view showing the structure, and FIG.
FIG. 3 is a view corresponding to (a sectional view taken along line CC in FIG. 2).

The partition 21D in the sixth embodiment is also formed from the upper inner wall 8 to the lower inner wall 7 of the intake ports 46A, 46B in the same manner as in the first embodiment, and the respective intake ports 46A, 46B are formed. It is provided so as to be bisected in the left-right direction. The partition walls 21D, 21D divide the interior of each intake port 46A, 46B into a center side (spark plug side) passage 4 and a side (anti-spark plug side) passage 5 along the flow direction of intake air. It has become.

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. The injector 12 has two intake ports 46 as in the first embodiment shown in FIGS.
Around the diverging portion 46C of the intake ports 46A and 46B, it is arranged along the reference plane 3 of the intake air flow, and injects fuel toward the downstream of the intake ports 46A and 46B. Moreover,
As shown by the injector injection axis 6 in FIG. 3, the injector 12 is configured to inject fuel from a lower portion between the intake ports 46A and 46B toward an upper portion downstream of the intake ports 46A and 46B. Then, the fuel injected upward is supplied to the intake port 46A, together with the intake air.
The air is guided into the combustion chamber 30 through the central passage 4 in the intake ports 46A and 46B by being guided by the partition walls 21D and 21D provided in the 46B.

Since the intake port structure of the stratified combustion internal combustion engine according to the sixth embodiment of the present invention is configured as described above, the same effects as those of the first embodiment can be obtained. That is, the fuel flows along the injector injection axis 6,
Since the fuel is injected upward, in the tumble flow Fm of the mixture formed near the spark plug 11, the flow outside the vicinity of the ignition plug 11 becomes richer than the flow inside the tumble flow Fm. In the combustion chamber 30, the ignition is ensured.

Further, the partition 21D is attached to the umbrella 56 of the intake valve 58.
By omitting the parts in the vicinity, the intake ports 46A, 4A can be formed without requiring a highly accurate manufacturing technique.
6B can be formed, and the number of manufacturing steps can be reduced. Next, an intake port structure of a stratified combustion internal combustion engine according to a seventh embodiment of the present invention will be described. FIG. 20 is a schematic partial cross-sectional view showing the structure, and FIG. 10 is a diagram corresponding to (CC cross-sectional view).

The partition 21E of the seventh embodiment is provided with respect to the partition 21D of the sixth embodiment by omitting a portion near the stem portion 57 of the intake valve 58. That is, as shown in the drawing, the end of the partition 21E is formed substantially parallel to the stem 57 of the intake valve 58, whereby the end of the partition 21E is formed in a straight line. If the gap between the stem 57 of the intake valve 58 and the end of the partition 21E is too large, the flow of intake air in the intake ports 46A and 46B may be disturbed, so that the gap is not too large. It is provided as follows.

Then, the injector 12 is connected to each of FIGS.
As in the first embodiment shown in FIG.
Around the branch portion 46C of 46B, it is disposed along the reference plane 3 of the intake air flow, and is configured to inject fuel downstream of the intake ports 46A, 46B. Moreover, FIG.
As shown by the injector injection axis 6, the injector 12 injects fuel from the lower side between the intake ports 46A and 46B toward the upper part on the downstream side of the intake ports 46A and 46B. Then, the fuel injected upward is supplied to the intake port 46A,
The air is guided into the combustion chamber 30 through the central passage 4 in the intake ports 46A, 46B by being guided by the partition walls 21E, 21E provided in the 46B.

Since the intake port structure of the stratified combustion internal combustion engine according to the seventh 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,
Manufacturing costs and man-hours can be reduced. Although the first to seventh embodiments mainly show the intake port 46A, the intake port 46A and the intake port 46B in each embodiment have substantially the same configuration.

[0084]

As described above in detail, according to the intake port structure of the stratified combustion internal combustion engine according to the first aspect,
In an internal combustion engine having an intake port having two combustion chamber openings respectively opened and closed by two intake valves, and configured so that an intake flow from the intake port becomes a tumble flow in the combustion chamber, the combustion chamber The ignition means for combustion is arranged at the center of the intake port, and is extended along the direction of the intake stream line on the upper surface of the intake port. Two partition walls are provided to divide the tumble flow into the central passage, and fuel injection means for injecting fuel toward the upper inner wall of the central passage is provided at or near the lower inner wall in the intake port. Is configured to be a stratified tumble flow having different fuel concentrations, so that the intake air taken from each intake port can be stratified into a layer of air and a layer of air-fuel mixture. Than the inner flow of tumble flow can be a rich mixture towards the outside of the flow of the ignition means near, it can be made reliable ignition in the combustion chamber.

Further, when a space is provided between the partition and the upper inner wall in the intake port, the flow of the air-fuel mixture in the intake port and the flow of air are reduced. Separation can promote stratification of the tumble flow of the mixture and the tumble flow of air. Thus, there is an advantage that the fuel efficiency can be improved and the exhaust gas can be reduced more reliably while maintaining a stable combustion state even with a lean mixture. Another advantage is that the weight of the intake port can be reduced.

Further, when the partition wall extends from the upper inner wall to the lower inner wall of the intake port, the flow of the air-fuel mixture in the intake port and the air The flow can be completely separated and the stratification of the mixture and the air-only layers can be further enhanced. Therefore, there is an advantage that the fuel consumption can be improved and the exhaust gas can be reduced more reliably while maintaining a stable combustion state even with a lean mixture.

[0087] As described in claim 4, an intake port having two combustion chamber openings which are respectively opened and closed by two intake valves is provided, and the intake flow from the intake port becomes a tumble flow in the combustion chamber. In the internal combustion engine configured as described above, ignition means for combustion is disposed at the center of the top of the combustion chamber, and the intake port moves from the upper surface to the lower surface in the intake port, Two partition walls extending along the line direction, and an auxiliary partition wall connecting the lower ends of both partition walls and vertically dividing the inside of the intake port, the upper inner wall in the intake port, the partition wall, and the auxiliary partition.
Fuel supply means is provided which is divided into an ignition means side surrounded by a wall and a non -ignition means side other than the ignition means side, and which supplies fuel to the ignition means side. By being configured to be a different stratified tumble flow, the intake flow sucked from each intake port is
A tumble flow stratified into layers of air and mixture
Mixture of less than stoichiometric air-fuel ratio
Has the advantage that a stable lean burn state can be obtained
You. Further, the flow on the outside (outer circumference portion) near the ignition means can be made a richer mixture than the flow on the inside (inner circumference portion) of the tumble flow. Therefore, ignition in the combustion chamber can be ensured, and even if the mixture is lean, a stable combustion state can be maintained, and the effect of improving fuel efficiency and reducing exhaust gas can be obtained more reliably.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an intake port structure of a stratified combustion 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 a stratified combustion 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 cross-sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a first embodiment of the present invention, and is a CC cross-sectional view in FIG.

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

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

FIG. 11 is a schematic partial cross-sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a second embodiment of the present invention, and FIG. 3 (CC cross section in FIG. 2) of the first embodiment; ) Corresponding figure

FIG. 12 is a schematic partial cross-sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a third embodiment of the present invention, and is a sectional view of FIG. FIG.

13 is a schematic partial sectional view showing an internal shape of an intake port structure of a stratified combustion internal combustion engine as a third embodiment of the present invention, and is an EE sectional view in FIG.

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

15 is a schematic partial sectional view showing an internal shape of an intake port structure of a stratified combustion internal combustion engine as a fourth embodiment of the present invention, and is a sectional view taken along line FF in FIG. 14;

FIG. 16 is a schematic perspective view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a fifth embodiment of the present invention, and is a view corresponding to FIG.

17 is a schematic partial sectional view showing the configuration of an intake port structure of a stratified combustion internal combustion engine as a fifth embodiment of the present invention, and is a sectional view taken along line XX in FIG.

18 is a schematic partial sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a fifth embodiment of the present invention, and is a sectional view taken along line VV in FIG.

19 is a schematic partial cross-sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a sixth embodiment of the present invention, and FIG. 3 (CC cross section in FIG. 2) of the first embodiment; FIG.

FIG. 20 is a schematic partial cross-sectional view showing a configuration of an intake port structure of a stratified combustion internal combustion engine as a seventh embodiment of the present invention, and FIG. 3 (CC cross section in FIG. 2) of the first embodiment; FIG.

FIG. 21 is a schematic longitudinal sectional view showing an intake port structure of a conventional stratified combustion internal combustion engine together with around a combustion chamber.

FIG. 22 is a schematic perspective view showing the intake port structure of a conventional stratified combustion internal combustion engine together with the surroundings of a combustion chamber.

FIG. 23 is a schematic cross-sectional view of a surface of a conventional stratified combustion internal combustion engine that is perpendicular to the flow direction of intake air in an intake port structure (FIG.
3 is a sectional view taken along the line DD in FIG.

24 is a cross-sectional view showing another example of a schematic cross section of a surface of the conventional stratified combustion internal combustion engine that is perpendicular to the flow direction of the intake air in the intake port structure (corresponding to a cross section taken along the line DD in FIG. 21); ).

FIG. 25 is a schematic longitudinal sectional view showing another example of the intake port structure of the conventional stratified combustion internal combustion engine.

FIG. 26 is a graph showing the effect of a tumble flow in a conventional stratified combustion internal combustion engine using a tumble flow.

[Explanation of symbols]

 1A, 1B Intake port axis 2 Intake valve axis 3 Intake port reference plane 4 Reference plane side (spark plug side) passage 5 Reference plane outside (anti-spark plug side) passage 6 Injector injection axis 7 Intake port bottom side inner wall 8 Intake Port upper side inner wall 11 Ignition plug as ignition means 12 Injector as fuel injection means 13 Intake port oblique lines 21, 21A-21E Partition walls 21F, 21G Auxiliary partition walls 22 Cylinder block 24 Cylinder bore 25 Cylinder 26 Piston 28 Cylinder head 30 Combustion chamber 34 Pent roof 40 ', 42' Intake passages 46A, 46B, 44 ', 40F, 42F Intake ports 46A-1, 46B-1 Upper half of intake port 46A-2, 46B-2 Lower half of intake port 47, 47A , 47B Exhaust port 56 Valve head 57 Valve Temu 58 Nagarekokoro of the intake valve 59 exhaust valve 60 exhaust passage Fa tumble flow in the tumble flow F1 intake port Fm air mixture

Continued on the front page (72) Inventor Yuki Tamura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Michihiro Hata 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors (56) References JP-A-60-147537 (JP, A) JP-A-60-233314 (JP, A) JP-A-4-15938 (JP, Y2)

Claims (4)

(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. In the above, a combustion ignition means is disposed at a central portion of a top of the combustion chamber, and is extended along an intake stream line direction on an upper surface in the intake port. Two partition walls are provided which are divided into a central passage and side passages on both sides of the central passage. Fuel injection means for injecting fuel toward an upper inner wall of the central passage is provided on a lower inner wall or in the vicinity of the intake port. An intake port structure for a stratified combustion internal combustion engine, wherein the tumble flow is provided so as to be a stratified tumble flow having different fuel concentrations. 2. The intake port structure for a stratified combustion internal combustion engine according to claim 1, wherein a space is provided between the partition and an inner wall on the upper surface side in the intake port. 3. The intake port structure for a stratified combustion internal combustion engine according to claim 1, wherein the partition wall extends from the upper inner wall to the lower inner wall of the intake port. 4. 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. In the above, a combustion igniting means is disposed at a central portion of a top portion of the combustion chamber, and the intake port is moved from an upper surface to a lower surface side in the intake port.
And two partition walls extending along the direction of the intake stream line;
By an auxiliary partition that connects the lower ends of both partition walls and vertically partitions the inside of the intake port, an upper side inner wall in the intake port and
Ignition means side and said surrounded by and the partition and an auxiliary partition wall
A fuel supply unit is provided which is partitioned from the non - ignition unit side other than the ignition unit side and supplies fuel to the ignition unit side, and the tumble flow is configured to be a laminar tumble flow having a different fuel concentration. Characterized by the fact that
The intake port structure of a stratified combustion internal combustion engine.