JPH05180090A - Fuel supply device in four-valve type internal combustion engine - Google Patents

Abstract

PURPOSE:To attain sure ignition and combustion of an intake mixture and sufficient cleanliness of exhaust gas, in a 4-valve type internal combustion engine formed by providing two intake valves and two exhaust valves relating to a single combustion chamber. CONSTITUTION:The inside of a combustion chamber 5 is divided with a spark plug 22 bordering into the first combustion chamber 5a of containing one intake valve 11 and one exhaust valve 13 and the second combustion chamber 5b of containing the other intake valve 12 and the other exhaust valve 14. A fuel injection amount by the first fuel injection valve 23 relating to the first combustion chamber 5a is set larger than a fuel injection amount by the second fuel injection valve 24 relating to the second combustion chamber 5b, and on the other hand, in the case of recirculating exhaust gas relating to both the combustion chambers 5a, 5b, a recirculating amount of exhaust gas relating to the first combustion chamber 5a is increased larger than a recirculating amount of exhaust gas relating to the second combustion chamber 5b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is of a so-called four-valve type in which two intake valves and two exhaust valves are provided for one combustion chamber provided with an ignition means such as a spark plug at a substantially center thereof. The present invention relates to a fuel supply device for sucking fuel into a combustion chamber of an internal combustion engine.

[0002]

2. Description of the Related Art In a four-valve internal combustion engine of this kind, one combustion chamber having an ignition plug is provided with two intake ports each having an intake valve and an exhaust port also having an exhaust valve. A first chamber including one intake port and one exhaust port with the ignition plug as a boundary, and a second chamber including the other intake port and the other exhaust port, while being disposed in a facing portion. The prior art is disclosed in Japanese Patent Publication No. 49-23848 and Japanese Utility Model Publication No. 57-2262.
No. 8 publication and the like.

[0003]

The four-valve internal combustion engine according to this prior art is configured as described above, so that the intake air-fuel mixture sucked from the two intake ports has a longitudinal loop. Although a vortex flow (tumble flow) is applied to promote the ignition and combustion of the intake air-fuel mixture, the air-fuel mixture having substantially the same air-fuel ratio is sucked from both the intake ports. If the air-fuel ratio of the intake air-fuel mixture is set to lean, not only will ignition and combustion of the intake air-fuel mixture become unstable, but drivability will be reduced, and unburned components such as hydrocarbons in the exhaust gas will increase. When the air-fuel ratio of the intake air-fuel mixture is set to be rich, the ignition / combustibility of the intake air-fuel mixture can be improved, but the combustion temperature rises and the amount of nitrogen oxides in the exhaust gas increases. There has been a problem to say.

The present invention solves the above problems by utilizing the characteristics of the four-valve internal combustion engine described above to perform stratified intake of a lean air-fuel mixture and a rich air-fuel mixture. At the same time, by applying exhaust gas recirculation to this, it is a technical subject to further purify the exhaust gas.

[0005]

In order to achieve this technical object, the present invention is directed to one combustion chamber provided with ignition means such as a spark plug, two intake ports each provided with an intake valve, and each of the two intake ports. A first combustion is provided in which two exhaust ports provided with an exhaust valve are arranged at opposite positions, and the combustion chamber includes one intake port with the ignition means as a boundary and one exhaust port facing the intake port. A four-valve internal combustion engine including a first combustion chamber, a second combustion chamber that includes the other intake port and the other exhaust port that faces the other intake port, and a first fuel injection valve for the first combustion chamber; A fuel injection valve for two combustion chambers is provided, and the fuel injection amount by the first fuel injection valve is set to be large and the fuel injection amount by the second fuel injection valve is set to be small, and further, the fuel injection valve is set to the first combustion chamber. First exhaust gas recirculation means, front A second exhaust gas recirculation means for the second combustion chamber is provided, and the second exhaust gas recirculation means sets a large amount of exhaust gas recirculation and the second exhaust gas recirculation means sets a small amount of exhaust gas recirculation. It was configured to do.

[0006]

[Operation] In this type of four-valve internal combustion engine, during the intake stroke due to the downward movement of the piston, each exhaust gas is introduced into each of the air-fuel mixtures flowing into the first combustion chamber and the second combustion chamber from both intake ports. A longitudinal vortex flow (tumble flow) can be applied in the longitudinal direction toward the port, and the intake air-fuel mixture of the two vortex flows (tumble flow) is mutually compressed in the compression stroke accompanying the upward movement of the piston. Compressed while mixing.

Therefore, as described above, the first fuel injection valve for the first combustion chamber and the second fuel injection valve for the second combustion chamber are provided to increase the fuel injection amount by the first fuel injection valve. The air-fuel ratio of the intake air-fuel mixture on the side of the first combustion chamber becomes rich, while the intake air on the side of the second combustion chamber becomes rich by adopting the configuration in which the fuel injection amount by the second fuel injection valve is set to be small. The air-fuel ratio of the air-fuel mixture becomes lean, in other words, the air-fuel ratio of the intake air-fuel mixture on the first combustion chamber side is made rich, and the air-fuel mixture of the second combustion chamber side is made a lean air-fuel ratio. Therefore, when the total air-fuel ratio of the intake air-fuel mixture as a whole is set to the lean side, reliable ignition / combustibility can be secured.

Further, when the exhaust gas is recirculated to each of the first combustion chamber and the second combustion chamber, the recirculation amount of the exhaust gas by the first exhaust gas recirculation means for the first combustion chamber is increased, By setting the amount of recirculation of exhaust gas by the second exhaust gas recirculation means to the second combustion chamber to be small, a large amount of exhaust gas is contained in the intake air-fuel mixture having a rich air-fuel ratio and high ignition / combustibility. For an intake air-fuel mixture with a lean air-fuel ratio and low ignition / combustibility, a small amount of exhaust gas can be recirculated to each, in other words, the exhaust gas is stratified in accordance with the stratified intake of the intake air-fuel mixture. Therefore, it is possible to reliably suppress the generation of harmful components without impairing the ignition / combustibility of the intake air-fuel mixture due to the exhaust gas recirculation.

[0009]

Therefore, according to the present invention, the characteristics of the four-valve internal combustion engine are utilized to form the stratified intake of the intake air-fuel mixture,
Since stratified recirculation of exhaust gas can be performed at the same time,
This has the effect of reliably achieving a reduction in fuel consumption rate and a cleaner exhaust gas.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. In the drawing, reference numeral 1 denotes a cylinder block having a cylinder bore 2, reference numeral 3 denotes a cylinder head fastened to the upper surface of the cylinder block 1, and a reciprocating piston 4 is provided in the cylinder bore 2 of the cylinder block 1. And the cylinder head 3 is inserted.
A combustion chamber 5 is formed on the lower surface of the recess.

Reference numerals 6 and 7 denote two intake ports that open into the combustion chamber 5, and reference numerals 8 and 9 similarly denote the combustion chamber 5.
And two exhaust ports 8 and 9 are shown in FIG. 2, and these intake ports 6 and 7 and exhaust ports 8 and 9 pass through substantially the center of the combustion chamber 5 and the crankshaft ( (Not shown), with the longitudinal center line 10 extending substantially parallel to the left and right sides being sandwiched, the left and right regions are distributed and arranged.
Further, intake valves 11 and 12 are provided at the openings of the intake ports 6 and 7 into the combustion chamber 5, and exhaust valves 13 and 14 are provided at the openings of the exhaust ports 8 and 9 into the combustion chamber 5. Are provided respectively. Further, intake pipes 15 and 16 for guiding air from an air cleaner (not shown) to the intake ports 6 and 7 are connected to the openings of the intake ports 6 and 7 to the side surface 3a of the cylinder head 3. Has been done.

On the other hand, inside the combustion chamber 5,
A raised portion 17 that divides the inside into a first combustion chamber 5a in which one intake port 6 and one exhaust port 8 open and a second combustion chamber 5b in which the other intake port 7 and the other exhaust port 9 open While the raised portion 17 is integrally formed so as to extend in a direction substantially perpendicular to the longitudinal centerline 10, the combustion chamber 5 is formed on the lower surface of the cylinder head 3 at both end portions of the raised portion 17. The squish areas 18 and 19 projecting inward are provided, and the left and right side surfaces of the raised portion 17 and the side surfaces of the squish areas 18 and 19 are formed into inclined surfaces 20 and 21. Further, in the cylinder head 3, the spark plug 22 is seen so that the electrode portion 22a of the spark plug 22 can be seen in both the first combustion chamber 5a and the second combustion chamber 5b at the location of the raised portion 17. Screw on.

Then, the intake pipe 1 to the first combustion chamber 5a
5, the first fuel injection valve 23 is configured to inject and supply fuel during the intake stroke, and the intake pipe 16 to the second combustion chamber 5b is configured to inject and supply fuel during the intake stroke. By providing the second fuel injection valves 24 respectively and injecting and supplying the fuel by these both fuel injection valves 23, 24, the overall total air-fuel ratio in the combustion chamber 5 becomes leaner than the theoretical air-fuel ratio. Some value in (eg about 23)
Setting the fuel injection amount from the first fuel injection valve 23 from the second fuel injection valve 24 so that the air-fuel ratio of the intake air-fuel mixture into the first combustion chamber 5a becomes, for example, about 18. While increasing the fuel injection amount, the fuel injection amount from the second fuel injection valve 24 is adjusted so that the air-fuel ratio of the intake air-fuel mixture into the second combustion chamber 5b becomes, for example, about 28. The fuel injection amount from the valve 23 is made smaller.

In the case of this embodiment, the first fuel injection valve 23 and the second fuel injection valve 24 inject fuel from the respective fuel injection valves 23, 24 as indicated by arrows 23a, 2 in FIG.
As shown by 3b and 24a, 24b, it is mainly configured to be performed in two directions, that is, a direction toward the spark plug 22 and a direction away from the spark plug 22.

Further, the intake pipe 15 to the first combustion chamber 5a
The first exhaust gas recirculation passage 25 from the exhaust system is connected to the intake pipe 16 to the second combustion chamber 5b, and the second exhaust gas recirculation passage 25 from the exhaust system is also provided.
When exhaust gas is recirculated by connecting the exhaust gas recirculation passages 26 to each other, the recirculation amount of the exhaust gas from the first exhaust gas recirculation passage 25 is returned to that of the exhaust gas from the second exhaust gas recirculation passage 26. More than the flow rate,
The recirculation amount of the exhaust gas from the second exhaust gas recirculation passage 26 is set to be smaller than the recirculation amount of the exhaust gas from the first exhaust gas recirculation passage 25.

The two exhaust gas recirculation passages 25, 26
The exhaust gas recirculation from the exhaust gas recirculation device is similar to the exhaust gas recirculation device that has been widely known from the past, in the idle operation region, the exhaust gas recirculation amount is reduced or the exhaust gas recirculation is cut, and in the partial load operation region. The recirculation amount of the exhaust gas is increased in proportion to the increase of the load, and the recirculation amount of the exhaust gas is reduced or the recirculation of the exhaust gas is controlled in the high load operation range.

In this structure, in the intake stroke due to the downward movement of the piston 4, each exhaust port is provided to each of the air-fuel mixtures flowing from the intake ports 6 and 7 into the first combustion chamber 5a and the second combustion chamber 5b. As shown by the arrow A in FIG. 1, it is possible to impart a loop-shaped vortex flow (tumble flow) in the vertical direction toward 8 and 9. Then, the intake air-fuel mixture of the two loop-shaped vortex flows (tumble flow) is compressed while being mixed with each other in the compression stroke accompanying the upward movement of the piston 4.

Therefore, as described above, the first fuel injection valve 23 for the first combustion chamber 5a and the second combustion chamber 5
By providing the second fuel injection valve 24 for b, and setting the fuel injection amount by the first fuel injection valve 23 to be large and the fuel injection amount by the second fuel injection valve 24 to be small, While the air-fuel ratio of the intake air-fuel mixture on the side of the first combustion chamber 5a becomes rich, the second combustion chamber 5b
Since it is possible to perform stratified intake so that the air-fuel ratio of the intake air-fuel mixture on the side becomes lean, reliable ignition / combustibility is ensured when the total air-fuel ratio of the intake air-fuel mixture as a whole is set to the lean side. It can be secured.

Further, the first combustion chamber 5a and the second combustion chamber 5
b), when the exhaust gas is recirculated through the first exhaust gas recirculation passage 25 and the second exhaust gas recirculation passage 26, the exhaust gas by the first exhaust gas recirculation means for the first combustion chamber By setting the recirculation amount to be large and the recirculation amount of the exhaust gas by the second exhaust gas recirculation means to the second combustion chamber to be small, the intake air-fuel mixture having a rich air-fuel ratio and high ignition / combustibility is A large amount of exhaust gas can be recirculated to each of the intake air-fuel mixture with a lean air-fuel ratio and low ignition / combustibility.
In other words, the exhaust gas can be recirculated in a layered manner in accordance with the stratified intake of the intake air-fuel mixture, so that the exhaust gas recirculation does not impair the ignition / combustibility of the intake air-fuel mixture and ensures the generation of harmful components. Can be suppressed.

The fuel injection valves 23 and 24 may be provided directly to the first combustion chamber 5a and the second combustion chamber 5b, and instead of the spark plug 22 in the above embodiment. For example, as described in Japanese Utility Model Publication No. 54-19441 and Japanese Utility Model Publication No. 54-38401, the sub chamber cup surrounding the ignition plug is provided with a plurality of ejection holes. It goes without saying that other ignition means may be applied.

[Brief description of drawings]

1 is a vertical sectional front view showing an embodiment of the present invention, which is indicated by I in FIG.
FIG. 3 is a sectional view taken along line I.

FIG. 2 is a bottom view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

 1 Cylinder Block 2 Cylinder Bore 3 Cylinder Head 4 Piston 5 Combustion Chamber 5a First Combustion Chamber 5b Second Combustion Chamber 6,7 Intake Port 8,9 Exhaust Port 11,12 Intake Valve 13,14 Exhaust Valve 15,16 Intake Pipe 17 Raised Part 22 Spark plug 23 First fuel injection valve 24 Second fuel injection valve 25 First exhaust gas recirculation passage 26 Second exhaust gas recirculation passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display area F02D 43/00 N 7536-3G F02M 69/00 360 G 9248-3G 69/04 R 9248-3G

Claims (1)

[Claims] 1. A combustion chamber provided with ignition means such as a spark plug, and two intake ports each provided with an intake valve, and two exhaust ports also provided with respective exhaust valves are provided at positions facing each other. On the other hand, a first combustion chamber including one intake port and one exhaust port facing the intake port, and the other intake port and the other exhaust port opposite to the intake chamber A four-valve internal combustion engine including a second combustion chamber including a first combustion chamber
A fuel injection valve and a fuel injection valve for the second combustion chamber are provided, and the fuel injection amount by the first fuel injection valve is set to be large and the fuel injection amount by the second fuel injection valve is set to be small, and A first exhaust gas recirculation means for the first combustion chamber and a second exhaust gas recirculation means for the second combustion chamber are provided to increase the amount of exhaust gas recirculation by the first exhaust gas recirculation means; A fuel supply device for a four-valve internal combustion engine, characterized in that the amount of exhaust gas recirculated by the exhaust gas recirculation means is set to be small.