JP2697518B2 - 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 for an internal combustion engine, and more particularly, to an intake port structure for an internal combustion engine configured such that intake air flows from a plurality of intake ports become a stratified tumble flow in a combustion chamber. Regarding port structure.

[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 ports in one combustion chamber has been used. I have. In such an internal combustion engine, the air-fuel mixture flows into the combustion chamber from each of the two intake ports.

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. 34 and 35 show the structure of one cylinder of a two-intake-port internal combustion engine that generates such 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 two intake passages provided for each cylinder. Intake ports 44 'of the intake passages 40' and 42 'are provided with intake valves 58, respectively.

[0004] The pent roof 34 has a plurality of intake passages 40 ',
The intake passages 40 ', 42' are provided with slopes so that the intake air flow from the intake passages 40 ', 42' can be guided downward along the inner wall surface of the cylinder bore 24 on the extension axis of each intake passage 40 ', 42'.
Is also assisted by the guidance of the pent roof 34 and proceeds in the tumble flow directions as indicated by arrows Fa and Fm, respectively.

In order to promote the tumble flow, the shape of the intake port 44 'is important.
4, the intake port 44 'is formed as a straight straight port as shown in FIG. 35, or the intake port 44' is narrowed as shown in FIG. 38 to rectify the flow. . In FIGS. 34 and 38, 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. 36, 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. 35, the injector 12 is provided only in one intake passage 42 ′, and the ignition plug 11 is arranged 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. . Also, the intake passage 40 '
From the intake port 44 ', only air flows into the combustion chamber 30 to form a tumble flow Fa of this 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 manner is effective for increasing the flame propagation speed and the combustion stability. FIG. 39 shows experimental data on the heat generation amount Q, the indicated mean effective pressure P, and the heat generation rate dQ. The cycle variation of the heat generation amount Q, the indicated average effective pressure P, and the heat generation rate dQ is greater when the tumble flow is generated than when the tumble flow is generated (a general case where the tumble flow is not particularly generated). It is clear that the combustion stability is good.

In FIG. 1, reference numeral 47 denotes an exhaust port communicating with the exhaust passage 60, and reference numeral 59 denotes an exhaust valve.

[0009]

However, as described above, in the case of the intake port 44 'having a circular or elliptical cross section, the intake port 4' is used to increase the tumble flow.
When the straight port 4 ′ is formed, the intake port 4
4 'enters the valve seat 62 at an acute angle, so that the cross-sectional area of the flow passage is inevitably reduced. As shown in FIG. And the maximum flow rate decreases. That is, when the strength of the tumble flow (tumble strength) is increased, the maximum flow rate (flow rate coefficient) is reduced. Such a decrease in the maximum flow rate undesirably causes a decrease in the full opening performance of the engine.

By the way, in order to strengthen the tumble flow, the flow rate (flow velocity) of the flow (see the arrow a shown in FIGS. 34 and 38) on the tumble flow side above the intake port with the center line of the intake valve 58 as a boundary. The flow on the opposite side (FIGS. 34 and 3
8 (see arrow b)). Therefore, if such an imbalance in flow rate (flow rate) can be positively formed, the strength of the tumble flow (tumble strength) can be increased without lowering the maximum flow rate (flow rate coefficient).

In recent years, an internal combustion engine has been operated with a fuel mixture having an amount smaller than the stoichiometric air-fuel ratio, and two intake ports are provided to reduce vibration and reduce fuel consumption. There is also a proposal for supplying an air-fuel mixture, but in this case, since the ignition plug is located between the two intake ports, if the operation is performed with a small amount of fuel, the ignitability may be deteriorated. Therefore, there is a problem that it is difficult to operate with a smaller amount of fuel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to promote stratification while enhancing the tumble flow of intake air in a cylinder, so that a mixture of fuel having an amount smaller than the stoichiometric air-fuel ratio can be obtained. However, it is an object of the present invention to provide an intake port structure of an internal combustion engine that can maintain a stable lean burn state.

[0013]

According to a first aspect of the present invention, there is provided an intake port structure for an 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 flow from the intake port becomes a tumble flow in the combustion chamber, the intake port is formed so that the formation of the tumble flow by the intake flow from the intake port is promoted. the tumble flow out side half portion is wider than the inner half of the intake flow heart of the intake port eccentric to tumble out of the side
The intake port is provided with a partition that divides the inside of the intake port along the flow direction of the fluid into the ignition means side and the anti-ignition means side of the combustion chamber, and is divided by the partition wall. It is characterized in that fuel injection means for injecting fuel is provided on the side of the ignition means inside.

According to a second aspect of the present invention, there is provided an intake port structure for an internal combustion engine having an intake port having two combustion chamber openings opened and closed by two intake valves, respectively, and an intake flow from the intake port. in There internal combustion engine configured such that a tumble flow in each combustion chamber, so that the formation of the tumble flow by the intake air flow from the intake port is accelerated, the intake port, the tumble flow outside half portion along with it widened than the inner half and the intake flow heart of the intake port is configured to eccentrically to the tumble flow out side, as inlet to the intake port smoothly flows, upstream of the intake port of the intake passage, the tumble flow out side half portion widened portion of the eccentric shape than the inner half portion is formed, the fluid and ignition means side of the combustion chamber through the intake port and the anti-ignition device side Flow Partition wall is provided that bisects along the direction, and is characterized in that the fuel injection means for injecting fuel is provided in the ignition means side in the intake port which is partitioned by the partition wall.

According to a third aspect of the present invention, there is provided an intake port structure for an internal combustion engine according to the first or second aspect of the present invention, wherein a combustion ignition means is provided at a central portion of a top portion of the combustion chamber. It is characterized by being. Therefore,
In this case, the fuel injection means injects fuel to the inside of the intake port (the side adjacent to each of the two port portions divided toward the two combustion chamber openings) corresponding to the position of the combustion ignition means. It is configured as follows.

[0016]

[Action] In the intake port structure for an internal combustion engine of the present invention of the above claim 1, the tumble flow out side half portion inner of the intake port
Since the intake air flow heart of the intake port is wider than the side halves are eccentrically to the tumble flow out side, the intake air flow component from the tumble flow outside half portion of the intake port is a component of the flow to form a tumble flow While the intake air flow component from the inner half of the intake port, which is a component that prevents the tumble flow, becomes weaker.

Thus, the intake air flowing into the combustion chamber from the opening of the combustion chamber of the intake port smoothly forms a tumble flow. At the same time, since the inside of the intake port is partitioned by the partition wall into the ignition means side and the anti-ignition means side,
The intake flow that has flowed into the intake port is divided by the partition into an ignition means side and an anti-ignition means side, and the fuel injected by the fuel injection means is mixed with the intake flow diverted to the ignition means side.

As a result, a stratified tumble flow of the mixture containing the fuel is formed on the ignition means side, and the fuel is supplied to the ignition means by the stratified tumble flow. Further, in the intake port structure for an internal combustion engine of the present invention described in claim 2, together with the intake port, the upstream side of the intake passage of the intake port also tumble flow out side half portion is wider than the inner half, since the intake air flow heart of the intake passage is eccentric to the tumble flow out side, the intake air flow while flowing through the intake passage, from the tumble flow outside half portion of the intake passage which is a component of flow which forms a tumble flow While the intake flow component becomes strong, the intake flow component from the inner half of the intake passage, which is a component that prevents the tumble flow, becomes weak.

Furthermore, the intake air flow, when flowing into the intake port, while the air flow component from the tumble flow outside half portion of the intake port is a component of the flow to form a tumble flow is stronger, prevents tumble flow The intake air flow component from the inner half of the intake port, which is a component of the intake port, becomes weak. This allows
The intake air flowing into the combustion chamber from the combustion chamber opening of the intake port forms a tumble flow more smoothly.

At this time, the inflow of intake air from the intake passage upstream of the intake port to the intake port is smoothly performed. Further, this intake air flow is divided into two by the partition wall into the ignition means side and the counter-ignition means side, and the fuel injected by the fuel injection means is mixed with the intake air stream which is divided into the ignition means side. As a result, a tumble flow of the air-fuel mixture is formed on the ignition means side, and fuel is supplied to the ignition means by the laminar tumble flow.

Further, in the intake port structure for an internal combustion engine according to the present invention, the fuel injection means is provided inside the intake port on the ignition means side (portion portions divided into two toward the two combustion chamber openings). In the intake port, the fuel is divided into an air-fuel mixture on the side of the ignition means and air on the side of the non-ignition means. Then, since the stratified tumble flow of the air-fuel mixture is formed in the central portion of the combustion chamber in which the ignition means is provided, the ignition of the air-fuel mixture is reliably performed.

[0022]

1 to 13 show an intake port structure of an internal combustion engine as a first embodiment of the present invention, and FIG. FIG. 2 is a schematic view showing the configuration of the engine, and FIG. 2 is a plan view showing a cylinder head portion and an intake manifold of the engine, and FIG. 3 is a schematic partial sectional view showing a shape inside the intake manifold. (A),
2B is a sectional view of an upstream portion of the intake manifold in FIG. 2, FIG. 2C is a sectional view taken along line GG in FIG. 2, and FIG.
2A to 2G are cross-sectional views taken along lines R1-R1 to R4-R4 in FIG. 2, and FIG. 4 is a schematic top view showing the configuration of FIG.
, FIG. 5 is a schematic partial cross-sectional view showing the configuration, and is a CC cross-sectional view in FIG. 4, and FIG. 6 is a schematic partial cross-sectional view showing the configuration. B
-B sectional view, FIG. 7 is a schematic view showing the operation, FIG.
9 to 13 are schematic diagrams showing variations of the fuel injection method, and FIGS. 9 to 13 are graphs for explaining the operation and effect.

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.
A combustion chamber 30 is formed by being surrounded by the cylinder head 6 and the cylinder head 28. Each cylinder of the internal combustion engine is configured as a four-valve internal combustion engine having two intake valves and two exhaust valves, and an intake port 46 is led into the combustion chamber 30. The intake port 46 is divided into two intake port portions 46 by a port partition (intake port branch portion) 46C in the middle.
A and 46B are provided as siamese ports, and an intake valve 58 is installed at the opening of the combustion chamber of each intake port portion 46A and 46B. The exhaust port 47 is also a siamese port, and two exhaust ports 47A and 47B are also guided into the combustion chamber 30, and exhaust valves (not shown) are provided.

As shown in FIGS. 1, 4 and 7,
As shown in FIG. 2, each intake port portion (hereinafter, this intake port portion is also simply referred to as an intake port) has an intake manifold 1 as an intake passage.
4 is connected. Also, in the figure, reference numerals 1A and 1B
Indicates the axis of each of the intake ports 46A and 46B (the center line of the upper and lower ends and the left and right ends). In addition, each exhaust port 47
A and 47B merge on the downstream side and are connected to a common exhaust passage (not shown).

In the vicinity of the branch portion 46C of the intake ports 46A, 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, the axial lines 1A and 1B of the intake ports 46A and 46B are shown in FIGS.
And two straight lines parallel to each other as shown in FIG. Therefore, the branch portion 4 of the intake ports 46A, 46B
Downstream from the vicinity of 6C, each intake port 46A, 46B
Are formed in parallel with each other, and each intake port 46A,
The intake air from 46B flows into the combustion chamber 30 in a state parallel to each other. That is, each intake port 46
A and 46B are formed in straight straight ports parallel to each other.

Furthermore, cross-sectional shape of the straight port, as shown in FIG. 6, the intake port 46A, the tumble flow outside half portion of the 46B (i.e. the main component stream flows intake port 46A to form a tumble flow, 46B of It met the upper half
(Hereinafter, also referred to as the tumble flow side half ) 46A-1,4
6B-1 is an inner half (that is, a lower half of the intake ports 46A, 46B through which a component flow for preventing a tumble flow flows , and hereinafter also referred to as the other half ) 46A-2, 46A.
It is wider than B-2, and the intake ports 46A, 46
B is located on the tumble flow side (that is, the intake port 4
6A, 46B are eccentric to the upper halves 46A-1, 46B-1). Thereby, the intake ports 46A, 46B
This facilitates the formation of a tumble flow within the combustion chamber 30 by the intake air flow from the combustion chamber 30. In the first embodiment, the intake ports 46A and 46B are formed to have a substantially inverted triangular cross section as shown in FIG. Reference numerals 21 and 21 shown in FIG. 6 denote these intake ports 46A and 46A.
The partition wall divides B into two, which will be described in detail later.

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.

FIGS. 3D to 3G show cross-sectional shapes of the intake ports 46A and 46B.
It shows a section from 1-R1 section to R4-R4 section. As shown in FIGS. 3D to 3G, the cross-sectional shape of each intake port 46A, 46B is set so that the intake flow from intake manifold 14 flows smoothly into intake ports 46A, 46B without resistance. As going toward the downstream side, the tumble flow side halves 46A-1, 46B-1 of the intake ports 46A, 46B become the other halves 46A-2, 46B-.
It is formed so as to be gradually widened more than 2.

As shown in FIGS. 1 and 7, a spark plug 11 as ignition means is disposed 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.

Then, as shown in FIG.
6A and 46B, the intake manifold 1
4 are provided, and the intake manifold 14 is provided.
, The intake air is taken into the intake ports 46A and 46B. The intake manifold 14 is arranged in order from the upstream side to the downstream side as shown in FIGS.
It has a cross-sectional shape as shown in FIG. That is, in the intake manifold 14, each intake port 46
A, 46B so that the intake air flows smoothly (that is,
Two intake passage portions 14A and 14B are formed so as not to lower the flow velocity of the intake air. On the upstream side of the intake manifold 14, as shown in FIGS. , 14B are not clearly formed, but as they move downstream, the cross-sectional shape that promotes the tumble flow becomes more prominent as shown in FIG. On the most downstream side connected to the intake ports 46A, 46B, the intake ports 46A, 46B and the intake manifold 14 are formed so that their cross-sectional shapes substantially match, and these two intake passage portions 14A, 14B are formed. Then, the intake air flows into each intake port 46A, 46B.

That is, the intake manifold 14
Inside, the two intake passage portions 14A and 14B define the tumble flow side halves 14A-1 and 14B as they go downstream, similarly to the cross-sectional shape of each intake port 46A and 46B.
-1 is formed so as to have an eccentric shape wider than the other half portions 14A-2 and 14B-2, thereby promoting a tumble flow.

As a result, the intake air flows through the two intake passage portions 14A and 14B in the intake manifold 14 so that the intake flow center F1 flows on the tumble flow side (that is, the two intake passage portions 14A and 14B).
A and 14B, which are eccentric to the upper half portions 14A-1 and 14B-1) and flow into the intake ports 46A and 46B, the formation of a tumble flow in each of the intake ports 46A and 46B is further promoted. I have.

As shown in FIGS. 1, 3 to 7, a partition wall 2 is formed in each of the intake ports 46A, 46B so as to bisect the inside of each of the intake ports 46A, 46B in the left-right direction.
1 is provided, and the partition 21 allows each intake port 4
6A and 46B, the passage of the ignition means side passage (or the center side passage) 4 on the reference surface 3 side of the intake flow and the passage of the anti-ignition means side passage (or the side passage) outside the reference surface 3 respectively. 5 are divided into two along the flow direction of the intake air.

As shown in FIG. 4, the partition wall 21 extends along the axial lines 1A and 1B of the intake ports 46A and 46B.
It is formed substantially vertically, and extends from near the disposition position of the injector 12 to the downstream side. Further, since the intake ports 46A and 46B are substantially parallel to each other, these partition walls 21 and 21 are also disposed substantially parallel to each other. Then, as shown in FIG. 5, in the first embodiment, the partition 2
1 is formed from the upper wall surface 8 to the lower wall surface 7 of the intake ports 46A, 46B.
B, the intake valve 5 along the axis 2 of the intake valve 58
The umbrella portion 8 extends to the vicinity of the umbrella portion 56. However, partition 2
1 is formed so as not to contact the umbrella portion 56 and the stem portion 57 of the intake valve 58 so as to secure an appropriate clearance therebetween, so that the operation of the intake valve 58 is not affected at all. I have.

Since the partition 21 only needs to prevent the fuel from entering the side passage 5 from the injector 12, the upstream end of the partition 21 does not necessarily extend to the upstream end of the intake port 46. good. Therefore, in this example, FIGS.
The partition 21 is formed in the middle of the intake port 46 as shown in FIG. Therefore, in the intake ports 46A and 46B, the intake air flows into the combustion chamber 30 while being separated from each other while being rectified by the partition 21 while being branched into the center side passage 4 and the side passage 5. It has become. As a result, the flow of the intake air is reduced by the partition 21 as described above.
As shown in FIG. 7, when the fuel flows into the combustion chamber 30, a layer Fm of an air-fuel mixture obtained by mixing fuel with air, and layers Fa and F of air only are mixed.
a (the center passage 4 and the side passages 5 on both sides thereof)
Are formed into a tumble flow in a state separated into a total of three flows (i.e., three flows), that is, in a layered state. 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 in the hatched portion 13 in FIGS. 4 and 6, the upper half portions 46A-1 and 46B-1 of the substantially inverted triangular cross section are made sufficiently large so as to cancel out the cross section integral, 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 the present embodiment, as shown in FIG. 4, the thickness of the partition 21 is equal to or slightly smaller than the diameter of the valve stem 57. Thereby, the intake resistance by the valve stem 57 can be reduced while securing the intake flow rate of the intake port 46, and the intake air flows into the combustion chamber 30 smoothly.

FIG. 7 shows a modified example of the partition 21. In this way, 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 the valve stem 57 approaches. 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.

Further, in the modification 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.

By the way, the injector 12 as the above-mentioned fuel injection means is arranged above the vicinity of the branch portion 46C of the two intake ports 46A, 46B as shown in FIGS. 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 lower surface downstream of the fuel cell. Reference numeral 6 in FIGS. 4, 5, and 7 denotes an injector injection axis, which indicates an 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 port 4
Partition walls 21 and 21 provided in 6A and 46B allow air to be sucked into the combustion chamber 30 through the central passage 4 in the intake ports 46A and 46B. , Only air flows.

Further, as an injection variation of the injector 12, the branch portion 4 of the two intake ports 46A and 46B is provided.
Types shown in FIGS. 8A to 8D can be considered according to the shape of 6C. (A) is for injecting fuel toward the branch portion 46C of the siamese type intake ports 46A and 46B. After the fuel is positively collided with the branch portion 46C,
The diffused fuel is caused to flow to the center side passage 4 in the intake ports 46A and 46B. This intake port 46
The branch portion 46C of A, 46B has a surface that is substantially perpendicular 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 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 which, contrary to the above (c), actively injects the fuel toward the wide angle over the partition walls 21 and 21. 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 flows into each of the intake ports 46A and 46B through the intake manifold 14. Then, after that, the fuel is mixed with the fuel injected by the injector 12, flows into the combustion chamber 30 from each of the intake ports 46A and 46B, and is compressed and expanded (exploded) in the combustion chamber 30. It is discharged from 47B to an exhaust passage (not shown).

In the intake manifold 14, the cross-sectional shape of the two intake passage portions 14A, 14B becomes smaller toward the downstream side.
Since the intake port 46A, 46B is formed into a shape that substantially matches the cross-sectional shape of the intake port 46A, the intake air that has flowed into each of the intake ports 46A, 46B from the intake manifold 14 smoothly without decreasing the flow velocity. Flows into.

In each of the intake ports 46A and 46B, the intake flow components in the tumble flow-side half portions 46A-1 and 46B-1 are much larger than the intake flow components in the other half portions 46A-2 and 46B-2. Become a lot. And the tumble flow side half portions 46A-1, 46 of the intake ports 46A, 46B.
The intake flow component entering the combustion chamber 30 from B-1 is a component of a flow that forms a tumble flow, and the intake port 46A,
The combustion chamber 30 from the other half 46A-2, 46B-2 of 46B.
Since the intake flow component that enters the inside is a component that blocks the tumble flow, the intensity of the tumble flow is increased due to the flow rate imbalance described above. In particular, the intake ports 46A, 4
Since the overall flow path cross-sectional area of 6B is reduced, the tumble flow can be enhanced while the flow rate (flow velocity) of the intake flow in the entire intake port is kept constant.

Here, the cross-sectional shape which promotes such a tumble flow is set in the intake manifold 14 in the form of a cross section.
Since it is also used in the two intake passage portions 14A and 14B, the intake air flow is diverted smoothly even before flowing into the intake ports 46A and 46B, and the flow resistance is reduced, that is, while the flow coefficient is increased. The tumble flow can be strengthened.

That is, the intake air flows through the two intake passage portions 14A and 14B in the intake manifold 14.
The intake flow center F1 is on the tumble flow side (that is, the upper half portions 14A-1, 14B-1 of the two intake passage portions 14A, 14B).
And flows into the intake ports 46A, 46B.
The tumble flow within the building is promoted.

At this time, at the time of intake, each intake port 4
In 6A and 46B, the partition 21 divides the intake air flow into an inner part and an outer part. Since the injector 12 injects fuel toward the center side passage 4 partitioned by the partition 21 of each of the intake ports 46A and 46B, the fuel flows through the center side passage 4 partitioned by the partition 21 of the intake ports 46A and 46B. In this passage 4, fuel and air are mixed. On the other hand, only air is sent to the outer side passage 5, and as shown in FIG. 1, a fuel-rich mixture layer Fm is formed in the vicinity of the ignition plug 11 at the center of the combustion chamber 30. An air layer Fa is formed on both sides.

In particular, since the intake ports 46A and 46B and the partition 21 provided therein are disposed substantially in parallel, as shown in FIG. 7, the intake ports 46A and 46B are provided.
A layer Fm of the air-fuel mixture flowing into the combustion chamber 30 from the center side passage 4 of FIG. 1 and a layer Fa of air flowing into the combustion chamber 30 from the outer passage 5 partitioned by the partition 21 are separated even in the combustion chamber 30. And is layered.

As a result, an air-fuel mixture containing less fuel is sent to the entire combustion chamber 30, but a sufficient amount of fuel for ignition is sent to the vicinity of the ignition plug 11. As described above, 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. is there.

Further, by promoting the stratification of the intake air flow, the formation of the tumble flow in the combustion chamber 30 is enhanced. That is, the intake air flow is supplied to each intake port 46A, 46B.
Is branched into a central passage 4 and a side passage 5 and the branched intake air flows into the combustion chamber 30 while maintaining a parallel state, whereby the intake air flow is rectified and a tumble flow is easily formed. It becomes.

FIG. 9 shows the intake manifold 1
4 is a graph showing the characteristics of the flow velocity of the intake air in the intake ports 46A and 46B. The horizontal axis of this graph shows the distance from the cylinder head surface 28A, and the vertical axis shows the flow velocity of the intake air. The values on the horizontal axis are outside the cylinder head 28, that is, plus on the upstream side of the intake air flow, and minus inside the cylinder head 28.

The line a in this graph indicates that the inside of the intake manifold 14 also has a tumble flow side half 14A-1,1.
This figure shows the characteristics of the intake flow velocity in the case of the present embodiment in which 4B-1 has a cross-sectional shape wider than the other halves 14A-2 and 14B-2 and is made smooth to the intake ports 46A and 46B. , Line b is designed to promote the tumble flow only at the intake ports 46A and 46B,
In FIG. 4, the characteristics of the intake air flow rate when a tumble flow having a conventional cross-sectional shape is used without considering the tumble flow are shown.

Then, as shown by the line a in this graph,
When the intake manifold 14 is formed so as to promote the tumble flow, the change in the flow velocity of the intake air in the intake manifold 14 becomes extremely smooth, and the intake flow velocity in the vicinity of the cylinder head surface 28A as indicated by the conventional line b. Will not drop sharply. That is, conventionally, when the intake air flows from the intake manifold 14 into the intake ports 46A, 46B, the flow of the intake air near the joint surface between the intake manifold 14 and the intake ports 46A, 46B due to the difference in their cross-sectional shapes. Was disturbed, and the intake flow velocity suddenly decreased as shown by the line b. However, by making the cross-sectional shapes of the intake manifold 14 and the intake ports 46A and 46B substantially coincide with each other, as shown by the line a, It is possible to eliminate a decrease in the intake flow velocity. Thus, the intake air is efficiently sucked into the combustion chamber 30.

Further, as shown in the graph of FIG. 10, by providing the partition walls 21 at the intake ports 46A and 46B to promote stratification of the mixture, the engine can be operated with a leaner mixture. Here, the horizontal axis of the graph of FIG. 10 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
Indicates the characteristics of an engine provided with a partition 21 at the intake port,
Lines b and d show the characteristics of an engine having a normal tumble flow intake port without the partition 21. Lines a and b relate to NOx emission, and lines c and d represent Pi.
It relates to the volatility.

First, the line a and the line b show the relationship between the A / F and the amount of NOx emission. 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). Further, the peak value of the NOx emission amount itself can be reduced. That is, since the stratification of the tumble flow in the combustion chamber 30 is promoted, the A / F at which the emission amount of NOx has a peak value moves to the lean side as compared with the conventional engine.

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, an engine which has extremely low fuel consumption and hardly emits NOx can be realized by this structure. Further, as shown in FIGS. 11 and 12, in this structure, the upper half portions 46A-1 and 46B-1 of the substantially inverted triangular cross sections of the intake ports 46A and 46B are formed sufficiently large, so that the engine is fully opened. The flow coefficient at the time can be secured.

That is, FIG. 11 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. In FIG. 11, □ indicates the average tumble ratio of an engine having a normal tumble flow intake port, and Δ indicates the upper half portion 46A-1, 46B- of the cross section of the intake port 46A, 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-
Since 1,46B-1 is made sufficiently large to secure the port cross-sectional area, both the average tumble ratio and the average flow coefficient can be improved as shown in the figure.

Thus, the relationship between the tumble ratio and the flow coefficient is as shown in FIG. FIG.
In the figure, the symbol “△” indicates an engine using a conventional tumble flow, the symbol “☆” indicates an engine in which the partition 21 is provided but the cross-sectional area in the intake ports 46A and 46B is reduced by the partition 21. An engine equipped with intake ports 46A, 4
The upper half portions 46A-1 and 46B-1 of the cross section of FIG. 6B are sufficiently enlarged.

That is, as shown in FIG. 12, 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 fully open performance is reduced. Can be Here, as indicated by the ★ mark, the 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. Thus, the intake port 46 provided by the partition 21 is provided.
It is possible to compensate for the decrease in the cross-sectional area of A, 46B, and to ensure the full opening performance of the engine.

FIG. 13 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 and the output of the engine.
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. 13, in the engine having this structure, the tumble ratio and the flow coefficient of the intake ports 46A and 46B are increased, so that an internal combustion engine having the same torque and output characteristics as the conventional engine can be realized. it can.

As described above, the partition walls 21 and 21 are provided in 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.

The structure of 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. Further, the upstream end of the partition 21 may be formed from the upstream end of the intake port 46. Next, an intake port structure of an internal combustion engine as a second embodiment of the present invention will be described.
FIG. 14 is a schematic partial cross-sectional view showing the configuration and corresponds to FIG.

The second embodiment differs from the first embodiment only in the internal shape of the intake manifold 14, and the other structure is the same as that of the first embodiment. As shown in FIG. 14, the intake manifold 14 has respective intake passage portions 14A, 14B.
Are divided into two in the left-right direction. The partition wall 15 is provided between the intake passage portions 14A, 14A.
B is provided from the upper end to the lower end of B, whereby, in each of the intake passage portions 14A and 14B,
The intake passage is divided into a central passage 4 ′ and a side passage 5 ′ along the flow direction of the intake air.

The partition wall 15 is located downstream of the intake manifold 14, that is, the intake ports 46A, 46A.
B is provided up to the vicinity of the joint surface with B, and the partition wall 15 and the partition walls 21 in the intake ports 46A, 46B separate the intake air flow into the central side passages 4, 4 'and the side passages 5, 5'. It has become. Since the intake port structure of the internal combustion engine as the second embodiment of the present invention is configured as described above, the same effects as those of the first embodiment can be obtained, and the stratification of the intake flow can be achieved. Can be further promoted.

That is, the central passages 4 and 4 'and the side passages 5 and 5' are also provided inside the intake manifold 14 by a simple structure in which the partition wall 15 similar to the partition wall 21 in the intake ports 46A and 46B is provided. Thus, the intake air flow branched into the mixture is completely separated into the air-fuel mixture and the air, whereby the lean air-fuel mixture can be reliably burned. Next, the third aspect of the present invention
The structure of an intake port of an internal combustion engine as an embodiment will be described. FIG. 15 is a schematic diagram showing the configuration of the intake port, and is a partial sectional view showing a cylinder head portion of the engine. FIG. 16 is a schematic diagram showing the configuration. 15A is a view taken in the direction of the arrow H in FIG. 15, and FIGS.
It is sectional drawing from S1 cross section to S6-S6 cross section.

The third embodiment differs from the first embodiment only in the internal structure of the intake manifold 14 and the intake ports 46A and 46B, and the other structures are the same as those of the first embodiment. It is. FIG.
As shown in FIG.
8 is provided with intake ports 46A and 46B, and the intake air is sent into the combustion chamber 30 through the intake ports 46A and 46B.

As shown in FIGS. 16A to 16G, the cross section of this straight port is
6A and 46B, the tumble flow-side halves 46A-1 and 46A of the intake ports 46A and 46B.
B-1 is formed to be gradually wider than the other halves 46A-2 and 46B-2. Thereby, the intake port 46
A, 46B, the intake flow center F1 is eccentric to the tumble flow side, and the intake flow from the intake ports 46A, 46B is transferred to the combustion chamber 3
It is easy to form a tumble flow within 0. In the third embodiment, the intake ports 46A, 46B
Has a substantially inverted triangular cross section toward the downstream side as shown in FIG.

As shown in FIGS. 16 (a) to 16 (g), in the intake ports 46A and 46B, a partition 21 is provided over substantially the entire length of the intake ports 46A and 46B. This partition wall is provided from the intake port lower wall surface 7 to the intake port upper wall surface 8 so as to divide the inside of the intake ports 46A, 46B into two in the left-right direction, thereby flowing into the intake ports 46A, 46B. The intake air flow is such that the intake air flow is branched into a central passage 4 and a side passage 5.

The intake ports 46A, 46B are
On the downstream side from the vicinity of the cross section S3-S3, each intake port 46
A and 46B are independent, and the upstream side is a Siamese type intake port in which the intake ports 46A and 46B share a part respectively. That is, FIG.
As shown in (a), two intake ports 46A, 46B
Is 1 near the cylinder head surface 28A which is the most upstream side.
Immediately thereafter, the flow of intake air is branched by the partition 21 into the central passage 4 and the side passage 5. Then, as shown in FIGS. 16 (b) to 16 (d), the central passage 4 is gradually divided into two parts, and the intake air is completely divided into two parts downstream of the cross section S4-S4 shown in FIG. 16 (e). You. The intake air flows thus divided into two flow into the combustion chamber by the intake valves 58, respectively. In FIG. 16A, the outer surface of the intake port 46 is hatched for convenience.

In FIGS. 16F and 16G, reference numeral 57 denotes a valve stem, and the partition 21 is formed with an appropriate clearance with respect to the valve stem 57. The intake ports 46A and 46B are
The cylinder head surface 28A is connected to an intake manifold (not shown), and the intake air flows into the intake ports 46A and 46B through the intake manifold. Further, in the intake manifold, only one intake passage is provided, and the intake flow is one flow before flowing into the intake ports 46A and 46B.

The injector 12 is disposed in the upper portion near the branch 46C of the two intake ports 46A and 46B, as in the first embodiment. The injector 12 is disposed along the reference plane 3 of the intake air flow between the two intake ports 46A, 46B, and the intake ports 46A, 46B.
The fuel is injected toward the lower surface downstream of 6B. Therefore, the fuel injected from the injector 12 flows into the combustion chamber 30 through the central passage 4,
The air flows into the combustion chamber 30 through the side passage 5.

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 above-described first embodiment can be obtained. The formation of the tumble flow and the stratification of the fuel can be promoted, while keeping the conventional shape. That is, the shape of the intake ports 46A and 46B is gradually increased so that the tumble flow side half portions 46A-1 and 46B-1 are wider than the other half portions 46A-2 and 46B-2, so that the intake air flowing from the intake manifold is formed. The tumble flow can be strengthened while suppressing the flow velocity decrease to a certain level.

As a result, a strong tumble flow is formed in the combustion chamber 30 and a layer Fm of the air-fuel mixture is formed on the ignition plug 11 side, so that the lean air-fuel mixture can be reliably burned. Further, by using the conventional intake manifold, the present combustion engine can be realized at extremely low cost.

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. 17 is a schematic partial sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). The fourth embodiment is different from the first embodiment only in the shape of the partition 21, and the other structure is the same as that of the first embodiment.

In the fourth embodiment, as shown in FIG. 17, the partition 21A is formed from the upper wall surface 8 to the lower wall surface 7 of the intake ports 46A, 46B. The partition 21B is also provided at the tip of the stem 57 of the intake valve 58 inside 46B. Thereby, the center side passage 4 and the side passage 5 are completely separated. Further, the valve stem 5 of the intake valve 58
Reference numeral 7 is provided so as 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 maintained until the intake air flows into the combustion chamber 30 from the intake valve 58.
They are kept completely separate. And
Due to such partitions 21A and 21B, even after the flow flows into the combustion chamber 30, the layer Fm of the air-fuel mixture and the layer F of the air
a, Fa (a total of three flows of the center side passage 4 and the side passages 5 on both sides thereof), that is, a layered state can be maintained. Therefore, the present internal combustion engine is configured as a stratified combustion internal combustion engine.

Also, as in the first embodiment, the intake port 4
The intake manifold 14 is connected to 6A and 46B. Downstream of the intake manifold 14, the two intake passage portions 14A, 1A are so arranged that the intake air flows smoothly into the respective intake ports 46A, 46B.
4B, and these two intake passage portions 1
The intake air flows from 4A and 14B into each intake port 46A and 46B.

That is, the intake manifold 14
The two intake passage portions 14A, 14B have the tumble flow side half portions 14A-1, 14B-1 and the other half portions 14A-2, 14B in the same manner as the cross-sectional shape of each intake port 46A, 46B.
An eccentric part wider than -2 is formed to promote the tumble flow. Since the intake port structure of the internal combustion engine according to 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 stratification of the intake flow can be achieved. Can be further promoted. That is, at the tip of the stem portion 57 of the intake valve 58, the partition wall 21 extends along the extension of the partition wall 21A.
With the simple configuration of adding B, the intake port 46
The intake air flow branched in A and 46B is completely separated, and stratification of the air-fuel mixture in the combustion chamber 30 can be realized more reliably. Thus, the lean air-fuel mixture can be reliably burned.

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. 18 is a schematic partial sectional view showing the structure, and FIG. (C-C cross-sectional view of FIG. 2). In the fifth embodiment, as in the fourth embodiment,
Only the shape of the partitions 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 fourth embodiments. This internal combustion engine is also configured as a stratified combustion internal combustion engine.

In this embodiment, as shown in FIG. 18, the partition 21C is formed parallel to each other on the lower half side of the intake ports 46A and 46B so that only this lower half is vertically divided into two parts. 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 as the fifth embodiment of the present invention is configured 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 fifth embodiment, the manufacturing cost of the upper half can be reduced by omitting the upper half of the partition 21 of the fourth embodiment, and the intake ports 46A and 46B. Weight can be reduced.

Next, the structure of the intake port of the internal combustion engine according to the sixth embodiment of the present invention will be described. FIG. 19 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 sixth embodiment is also the first partition.
Upper wall surface 8 of intake ports 46A and 46B as in the embodiment.
And is formed in parallel from the lower wall surface 7 so as to divide the intake ports 46A and 46B into two in the left-right direction. The partition walls 21D, 21D divide the inside of each intake port 46A, 46B into an ignition means-side passage (center side passage) 4 and a counter-ignition means-side passage (side passage) 5 along the flow direction of intake air. Have been.

Further, as shown in FIG.
D is the intake valve 5 from the upstream side of the intake ports 46A and 46B.
The umbrella portion extends to a position just before the umbrella portion 8 of FIG. 8, and a portion near the umbrella portion 56 in the partition wall 21 of the first embodiment is omitted. Since the intake port structure of the internal combustion engine as the sixth 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. In other words, by forming the partition 21D by omitting a portion near the umbrella portion 56 of the intake valve 58, the intake ports 46A and 46B can be formed without requiring a highly precise manufacturing technique.

Next, the structure of an intake port of an 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. (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 of the seventh embodiment is provided in the same manner as the partition 21D of the sixth 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 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, the manufacturing cost and the number of steps can be reduced. In the fourth to seventh embodiments, the upstream end of each partition is connected to the intake port 46.
A and 46B are extended to the ends, but these partition walls are shown in FIG. 5 of the first embodiment as long as the air-fuel mixture and the air can be branched into the center side passage 4 and the side passage 5. Thus, it is not necessary to provide the end portions of the intake ports 46A and 46B.

In the fourth to seventh embodiments, the intake manifold 14 is constructed by using the same one as in the first embodiment. However, in the case of the structures of the fourth to seventh embodiments, too. As in the second embodiment, the intake manifold 14 having the partition wall 15 therein may be used. At this time, the upstream end of each partition in the fourth to seventh embodiments is provided up to the ends of the intake ports 46A and 46B, and is smoothly connected to the partition 15 in the intake manifold 14, so that stratification of the intake flow is achieved. Further promoted.

Further, also in the case of the structures of the fourth to seventh embodiments, similarly to the third embodiment, the intake ports 46A, 4
It is conceivable to gradually change the cross-sectional shape in 6B, thereby enhancing the tumble flow. In this case, a conventional intake manifold may be used in which the intake air flow is not separated in the intake manifold and becomes one flow.

By the way, the intake ports 46A, 46B and the exhaust ports 47A, 47B are not limited to straight lines that are substantially parallel in a plan view, but may actually be inclined or curved. It is also conceivable. Further, various shapes are also conceivable for the inverted triangular port that promotes tumble flow. Therefore, in the following embodiments, variations taking these factors into consideration will be described.

First, the structure of an intake port of an internal combustion engine according to an eighth embodiment of the present invention will be described with reference to FIGS.
7 shows an intake port structure of an internal combustion engine as an eighth embodiment of the present invention. FIG. 21 is a schematic plan view thereof, and FIG.
23 is a schematic partial longitudinal sectional view, FIG. 23 is a schematic sectional view of a plane orthogonal to the flow direction, and FIGS. 24 to 26 show various examples of the sectional shape of the plane orthogonal to the flow direction, respectively.
FIG. 27 is a schematic plan view corresponding to FIG. 21 and FIG. 27 is a schematic plan view corresponding to FIG. The internal combustion engine is also configured as a stratified combustion internal combustion engine.

As shown in FIGS. 21 and 22, each cylinder of the internal combustion engine having the intake port structure according to the first embodiment has a cylinder bore 24 formed in a cylinder block 22, a piston 26, and a cylinder head. 28, a combustion chamber 30 is formed. In the combustion chamber 30,
The two intake ports 46A and 46B are led, and an intake valve 58 is provided, respectively. 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 merge at the upstream side and are connected to the common intake passage 43, and the exhaust ports 47A and 47B merge 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.
0 is located between the intake ports 46A and 46B.

A pent roof 34 is formed on the upper wall 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.

Each intake port 46 of the internal combustion engine
A and 46B are formed as straight straight ports, as shown in FIG. 22, 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 eighth 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. 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 46B (see FIGS. 21 and 23). In addition, the intake valve 5
The eighth valve stem 57 penetrates the partition 21 in the vertical direction.

The intake port 46A with the partition 21 is provided.
46B, its tumble flow side half 46A-1,4
As a cross-sectional shape for widening 6B-1 more than the other half portions 46A-2 and 46B-2, in addition to the cross-sectional shape shown in FIG. 25, the other half 46A-2, 4 as shown in FIG.
26B-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 10 is supplied with a mixture of 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 10 for ignition.
Therefore, since a location where fuel is rich can be formed near the spark plug 10, the engine can be operated with a fuel mixture of an amount smaller than the stoichiometric air-fuel ratio without deteriorating ignitability.

The intake air 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 air 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 eighth embodiment, as shown in FIG. 27, two intake ports 46A and 46B and two exhaust ports
7 can be similarly applied to a three-valve internal combustion engine having one. Next, an intake port structure of an internal combustion engine as a ninth embodiment of the present invention will be described.
8 is a schematic plan view, FIG. 29 is a schematic cross-sectional view of a plane orthogonal to the flow direction, and FIGS. 30 to 32 correspond to FIG. 29 showing various examples of the cross-sectional shape of the plane orthogonal to the flow direction. FIG. 33 is a schematic cross-sectional view showing the modification, and FIG.
FIG. 9 is a schematic plan view corresponding to FIG. This internal combustion engine is also configured as a stratified combustion internal combustion engine.

Now, in the internal combustion engine having the intake port structure according to the ninth embodiment, unlike the eighth embodiment, the partition 21 is not provided at both intake ports 46A and 46B, and FIGS. As shown in FIG.
Only the 6A is divided into two parts by a partition 21 into a center side and an outside, and the injector 12 is attached to one of the intake ports 46A. The other structure is the same as that shown in the above-described eighth embodiment. It is.

That is, into the combustion chamber 30, two intake ports 46A and 46B are led, and the intake valves 58 are respectively installed, and two exhaust ports 47A and 47B are also led, and the exhaust valves are respectively installed. Further, the intake ports 46A and 46B are joined on the upstream side to form a common intake passage 4
3 and each exhaust port 47A, 4
7B are joined on the downstream side and connected to the common exhaust passage 60 in communication.

Further, in the center of the cylinder 25, a spark plug 10 as ignition means is provided with intake ports 46A, 46A.
B is provided in the middle of the combustion chamber 30.
A pent roof 34 is formed on an upper wall portion of the cylinder port 24. The pent roof 34 receives an intake flow from each of the intake ports 46A and 46B along an inner wall surface of the cylinder bore 24 on an extension axis of each of the intake ports 46A and 46B. It has a slope that can be guided downward.

Further, each intake port 46 of this internal combustion engine is
A and 46B are formed in a linear straight port, and the cross-sectional shape of this straight port is shown in FIG.
As shown in the figure, the tumble flow side halves of the intake ports 46A, 46B (that is, the upper halves of the intake ports 46A, 46B through which the main component flow forming the tumble flow flows) 46A-1, 46A.
6B-1 is wider than the other half (i.e., the lower half of the intake ports 46A, 46B through which the component flows that block the tumble flow) 46A-2, 46B-2, and the intake ports 46A, 46B, The intake flow center of 46B is located on the tumble flow side (that is, the upper half 46A-1, 46A-1 of the intake ports 46A and 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. Also in this embodiment, the intake ports 46A and 46B are formed to have a substantially inverted triangular cross section.

Further, inside one intake port 46A,
A partition 21 is provided so as to divide the intake port into two parts in the left-right direction, and the partition 21 allows the inside of the intake port 46A to be positioned between the ignition plug side (center side) and the anti-spark plug side (outside) in the flow direction of the air-fuel mixture. Along the way.
An injector 12 as fuel injection means is attached to one intake port 46A.
The fuel is supplied to the center side of the intake port 46A partitioned by the partition 21 (see FIGS. 28 and 29).

The intake port 46A with the partition 21 and the intake port 46B without the partition 21 also have a tumble flow side half 46A- like the first embodiment described above.
The cross-sectional shape for widening 1, 46B-1 more than the other half portions 46A-2, 46B-2 is, as shown in FIG. 29, a baseball home base shape as shown in FIG. The other half 46A- as shown in FIG.
2, 46B-2 with roundness and tongue shape,
As shown in FIG. 32, various intake ports 47A partitioned by the partition 21 are formed into a baseball home base shape, and the intake port 46B without the partition 21 is formed into a baseball home base shape. Can be

With such a configuration, at the time of intake,
Only air is sent to the outside of the intake port 46A partitioned by the partition 21 and to the intake port 46B, and fuel is sent only to the central side partitioned by the partition 21 of the intake port 46A. As in the example, the fuel and the air are stratified, and the ignition plug 10 is supplied with a rich mixture of the fuel. For this reason, a mixture containing less fuel is sent to the entire combustion chamber 30, and a sufficient amount of fuel for ignition is sent to the spark plug 10. Therefore, a fuel-rich area can be formed near the spark plug 10, and the engine can be operated with a fuel mixture of a smaller amount than the stoichiometric air-fuel ratio without deteriorating ignitability.
Tumble flow side half 46A of each intake port 46A, 46B
-1, 46B-1 and the other half 46A-
2, 46B-2, which is much stronger than the intake flow component. That is, the intake flow components from the tumble flow side halves 46A-1 and 46B-1 of the intake ports 46A and 46B are components of the flow forming the tumble flow, and
Since the intake air flow components from the other halves 46A-2 and 46B-2 of A and 46B are components that hinder the tumble flow, the above flow rate imbalance reduces the overall flow path cross-sectional area of the intake port. That is, the strength of the tumble flow can be increased while keeping the flow rate (flow velocity) of the intake flow in the entire intake port constant.

In the ninth embodiment, as shown in FIG. 33, two intake ports 46A and 46B and two exhaust ports
7 can be similarly applied to a three-valve internal combustion engine having one. Note that, as shown in the eighth and ninth embodiments,
The cross-sectional shapes of the intake ports 46A and 46B are the first to seventh.
Of course, it can be applied to the embodiment. Furthermore, it is conceivable to combine the configurations of the respective units of the above-described embodiments in a form different from the above.

[0117]

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, the intake port is formed such that the formation of the tumble flow by the intake flow from the intake port is promoted. but the tumble flow side outer halves are wider than the inner half of the intake flow heart of the intake ports eccentrically to the tumble flow outwardly
The intake port is provided with a partition that divides the inside of the intake port along the flow direction of the fluid into the ignition means side and the anti-ignition means side of the combustion chamber, and is divided by the partition wall. A flow that forms a tumble flow by a configuration in which fuel injection means for injecting fuel is provided on the side of the ignition means inside
Flows through the outer half of the tumble flow of the intake port
The intake component becomes stronger, while the component that prevents tumble flow
The intake flow component flowing inside the tumble flow of the intake port
The advantage that the tumble flow can be strengthened because it becomes weak
There is. Also, the inside of the intake port is separated from the ignition means by a partition.
Intake air flow that halves into the ignition means side with the anti-ignition means side
By supplying fuel to the combustion chamber from each intake port
The intake air flow sucked into the two air (or lean)
Gas mixture) and gas mixture layers.
There are advantages that can be done. In addition, the three layers
Tumble flow perpendicular to the cylinder center axis in the combustion chamber
Vertical swirling flow around the axis
The tumble flow into a relatively rich mixture.
Even if the overall air-fuel ratio in the combustion chamber is lean,
Benefits of improved combustion and improved lean limits
There is also. This also makes it possible to create an extremely fuel-efficient internal combustion engine.
There is an advantage that it can be realized. Furthermore, NO
There is an advantage that x emission can also be reduced.

Further, according to the intake port structure for an 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 an internal combustion engine in which the intake air flow is formed into a tumble flow in the combustion chamber, the intake port is moved outside the tumble flow side so that the formation of the tumble flow by the intake air flow from the intake port is promoted. with the halves being wider than the inner half of the intake flow heart of the intake port is configured to eccentrically to the tumble flow out side, as inlet to the intake port smoothly flows, of the intake port An eccentric portion in which the tumble flow side half is wider than the other half is formed in the upstream intake passage, and the inside of the intake port is fluidized to the ignition means side and the anti-ignition means side of the combustion chamber. of Re partition wall bisecting are provided along the direction, and, the configuration of a fuel injection means for injecting fuel into the ignition means side in the intake port which is partitioned by the partition wall is provided, effects and advantages as in claim 1 In addition to
As the flow coefficient in the intake passage is improved,
The filling efficiency has been improved, and the output can be improved.
There are advantages. In addition, the intake flow velocity in the intake port has been reduced.
This allows the intake air flow to flow into the combustion chamber without
This further enhances the tumble flow.

Further, according to the above-described structures of claims 1 and 2,
As in the case of the intake port structure for an internal combustion engine according to the third aspect of the present invention, the same effect as described above can be obtained even when a configuration is provided in which a combustion ignition means is provided at the center of the top of the combustion chamber. In addition to this, there is an advantage that it can be effectively used particularly for a four-valve internal combustion engine and the like.

[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 view showing an intake port structure of an internal combustion engine as a first embodiment of the present invention, and is a plan view showing a cylinder head portion and an intake manifold of the engine.

FIGS. 3A and 3B are schematic diagrams showing an intake port structure of an internal combustion engine as a first embodiment of the present invention, wherein FIGS. 3A and 3B show the inside of an upstream portion of an intake manifold, and FIG.
5-R5, R6-R6 sectional view, (c) is G in FIG.
-G sectional view, (d)-(g) are R1-R1 in FIG.
It is sectional drawing from a cross section to R4-R4 cross section.

FIG. 4 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. 5 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.

6 is a schematic partial sectional view showing the 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. 7 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. 8 is a schematic diagram 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. 9 is a graph showing characteristics of an intake flow velocity in an intake port structure of an internal combustion engine as a 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 graph showing the effect of the intake port structure of the internal combustion engine as the first embodiment of the present invention.

FIG. 12 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. 13 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. 14 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, and is a view corresponding to FIG. 3 (c).

FIG. 15 is a schematic view showing an intake port structure of an internal combustion engine as a third embodiment of the present invention, and is a partial sectional view showing a cylinder head portion of the engine.

16A and 16B are schematic diagrams showing an intake port structure of an internal combustion engine as a third embodiment of the present invention, wherein FIG. 16A is a view as viewed from an arrow H in FIG. 15, and FIGS. It is sectional drawing from S1-S1 cross section to S6-S6 cross section.

FIG. 17 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. 5 (a sectional view taken along line CC in FIG. 4) in the first embodiment; Corresponding figure

FIG. 18 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. 5 (a sectional view taken along line CC in FIG. 4) in the first embodiment. It is a corresponding figure.

FIG. 19 is a schematic partial cross-sectional view showing a configuration of an intake port structure of an internal combustion engine as a sixth embodiment of the present invention, which is shown in FIG. 5 (CC cross section in FIG. 4) in the first embodiment. It is a corresponding figure.

20 is a schematic partial sectional view showing the configuration of an intake port structure of an internal combustion engine as a seventh embodiment of the present invention, which is shown in FIG. 5 (a sectional view taken along line CC in FIG. 4) in the first embodiment. It is a corresponding figure.

FIG. 21 is a schematic plan view of an intake port structure of an internal combustion engine as an eighth embodiment of the present invention.

FIG. 22 is a schematic partial longitudinal sectional view of an intake port structure of an internal combustion engine as an eighth embodiment of the present invention.

FIG. 23 is a schematic sectional view of a plane orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as an eighth embodiment of the present invention.

FIG. 24 is a schematic cross-sectional view showing another example of a cross-sectional shape of a surface orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as an eighth embodiment of the present invention, corresponding to FIG.

FIG. 25 is a schematic cross-sectional view showing another example of a cross-sectional shape of a surface orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as an eighth embodiment of the present invention, corresponding to FIG.

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

FIG. 27 is a schematic plan view showing a modification of the intake port structure of the internal combustion engine as the eighth embodiment of the present invention in correspondence with FIG.

FIG. 28 is a schematic plan view of an intake port structure of an internal combustion engine as a ninth embodiment of the present invention.

FIG. 29 is a schematic cross-sectional view of a plane orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as a ninth embodiment of the present invention.

30 is a schematic cross-sectional view showing another example of a cross-sectional shape of a surface orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as a ninth embodiment of the present invention in correspondence with FIG. 29.

FIG. 31 is a schematic sectional view showing another example of a sectional shape of a surface orthogonal to a flow direction of intake air in an intake port structure of an internal combustion engine as a ninth embodiment of the present invention in correspondence with FIG.

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

FIG. 33 is a schematic plan view showing a modification of the intake port structure of the internal combustion engine as the ninth embodiment of the present invention in correspondence with FIG.

FIG. 34 is a schematic longitudinal sectional view showing a conventional intake port structure of an internal combustion engine together with around a combustion chamber.

And FIG. 35 is a schematic perspective view showing a conventional intake port structure of an internal combustion engine together with around a combustion chamber.

36 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. 34).
FIG.

FIG. 37 is a cross-sectional view (a view corresponding to a cross section taken along the line DD in FIG. 34) 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. 38 is a schematic longitudinal sectional view showing another example of the conventional intake port structure of the internal combustion engine.

FIG. 39 is a graph showing an effect of a tumble flow in a conventional internal combustion engine using a tumble flow.

[Description of Signs] 1A, 1B Intake port axis 2 Intake valve axis 3 Intake port reference plane 4, 4 'Central side passage as ignition means side passage 5, 5' Side passage as anti-ignition means side passage 6 Injection injection axis 7 Intake port lower wall surface 8 Intake port upper wall surface 11 Ignition plug as ignition means 12 Injector as fuel injection means 13 Intake port oblique portion 14 Intake manifold as intake passage 14A, 14B Intake passage portion 14A-1, 14B-1 Tumble flow outside half of intake passage
Portion ( upper half ) 14A- 2 , 14B- 2 Tumble flow inner half of intake passage
Portion ( lower half ) 15, 21, 21A to 21E Partition wall 22 Cylinder block 24 Cylinder bore 25 Cylinder 26 Piston 28 Cylinder head 28A Cylinder head surface 30 Combustion chamber 34 Pent roof 35 Recess 37 Slope 39 Ridge 40 ', 42' Intake Passageway 46, 44 ', 40F, 42F Intake port 46A, 46B Intake port portion 46C Port partition or intake port branch 46A-1, 46B-1 Tumble flow outside of intake port
Half ( upper half ) 46A-2, 46B-2 Tumble flow inside the intake port
Half ( lower half ) 47, 47A, 47B Exhaust port 56 Valve head 57 Valve stem 58 Intake valve 59 Exhaust valve 60 Exhaust passage 62 Valve seat Fa Tumble flow of air Fm Tumble flow of mixture F1 In intake port Heart of

 ──────────────────────────────────────────────────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 (72) Inventor Nobuaki Murakami 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Keizo Furukawa 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Uniform Iwichimichi 5-33-8 Shiba, Minato-ku, Tokyo No. Mitsubishi Motors Corporation (72) Inventor Masayuki Mochimo 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Katsuo Akishino 5-33 Shiba, Minato-ku, Tokyo No. 8 Mitsubishi (56) References JP-A-60-147537 (JP, A) JP-A-60-233314 (JP, A) JP-A-4-15938 (JP, U)

Claims (3)

(57) [Claims] An intake port having two combustion chamber openings opened and closed by two intake valves, respectively.
In the internal combustion engine configured such that the intake flow from the intake port becomes a tumble flow in the combustion chamber, the intake port is formed such that the formation of the tumble flow by the intake flow from the intake port is promoted. as a tumble flow out <br/> side half portion is wider than the inner half of the intake flow heart of the intake port is configured to eccentrically to the tumble flow out side, of the combustion chamber through the intake port Partition walls are provided on the ignition means side and the counter-ignition means side along the fluid flow direction, and fuel injection means for injecting fuel is provided on the ignition means side in the intake port partitioned by the partition walls. An intake port structure for an internal combustion engine, characterized in that: 2. An intake port having two combustion chamber openings opened and closed by two intake valves, respectively.
In the internal combustion engine configured such that the intake flow from the intake port becomes a tumble flow in the combustion chamber, the intake port is formed such that the formation of the tumble flow by the intake flow from the intake port is promoted. the tumble flow out <br/> side halves together than the inner half portion is widened intake flow heart of the intake port is configured to eccentrically to the tumble flow out side, intake air smoothly to the intake port as flows, the upstream side of the intake passage of the intake port, the inner tumble flow out side half portion
An eccentric portion that is wider than the side half is formed, and a partition wall that bisects the inside of the intake port along the flow direction of the fluid on the ignition means side and the anti-ignition means side of the combustion chamber is provided, An intake port structure for an internal combustion engine, wherein fuel injection means for injecting fuel is provided on an ignition means side in the intake port partitioned by the partition. 3. A combustion ignition means is provided at a central portion of a top portion of the combustion chamber.
Or an intake port structure for an internal combustion engine according to 2.