JP2000248939A - Engine with auxiliary chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel consumption and startability, suppress generation of unburned gas in low/intermediate speed regions, and reduce a content of NOx in exhaust gas, while ensuring fluidity of air and combustion gas. SOLUTION: A tip end part 16a of a fuel injection nozzle 16 is faced to an auxiliary chamber 30, a position of a main/auxiliary chamber side openings 40a, 40b of a communication hole 40 is displaced when one or a plurality of the communication holes 40 are viewed in a cylinder center axial direction, so as to generate an eddy current by a new air current flowing in the auxiliary chamber from a main combustion chamber side in a compression stroke, and an injection hole 16b is arranged in the tip end part 16a in a manner, wherein the center line of at least one or more the injection holes 16b is made to pass in an extended condition, in a range of perspective shadow of a new air current 50 formed on an auxiliary chamber inner wall 30a from a bottom wall 30a1 over to a ceiling wall 30a3 via a sidewall 30a2, when the new current 50 is seen through by placing a view point in the tip end part 16a of the injection nozzle 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine with a sub-combustion chamber for generating a swirl of compressed air in a sub-combustion chamber.

[0002]

2. Description of the Related Art Conventionally, as an engine, a combustion chamber is constituted by a main combustion chamber in a cylinder and a sub-combustion chamber provided in a cylinder head connected to the main combustion chamber through a communication hole. With the tip of the fuel injection nozzle facing the chamber,
There is a vortex generated in the sub-combustion chamber due to fresh air from the communication hole, in which fuel is injected from the injection hole at the tip.

[0003] As this type of engine, there are four-cycle and two-cycle diesel engines. In the compression stroke, fresh air flows from the main combustion chamber through the communication hole into the sub-combustion chamber, and is compressed into the sub-combustion chamber. A swirl of air is generated, and fuel is injected into the swirl to ignite and burn.

[0004]

As described above, in the engine with the sub-combustion chamber, a vortex is formed in the sub-combustion chamber by the communication hole, the fuel injected from the fuel injection nozzle is quickly mixed, and the ignitability and the flammability are improved. Is secured. In addition, due to the strong eddy current, the air utilization rate is good and output is easy to obtain, and NO
There are advantages such as that x emission can be reduced.

[0005] However, as air and combustion gas move through the communication hole, a throttling loss occurs, resulting in deterioration of fuel consumption and startability. For this reason, it is conceivable to increase the hole area of the communication hole, but as the hole area increases, the eddy current weakens,
There are problems such as an increase in unburned gas in the low to medium speed range, resulting in deterioration of fuel efficiency, a prolonged ignition delay period, an increase in premixed combustion ratio, and an increase in NOx in exhaust gas.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and aims to improve fuel efficiency and startability while ensuring fluidity of air and combustion gas, and to improve low and medium speed. It is an object of the present invention to provide an engine with a sub-combustion chamber in which the generation of unburned gas in the region is suppressed and the NOx content in exhaust gas is small.

[0007]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention has the following constitution.

According to the first aspect of the invention, there is provided a combustion chamber comprising a main combustion chamber in a cylinder and a sub combustion chamber provided in a cylinder head which communicates with the main combustion chamber via one or more communication holes. The tip of the fuel injection nozzle faces the sub-combustion chamber, and the position of the main combustion chamber-side opening and the sub-combustion chamber-side opening of the communication hole is shifted when the communication hole is viewed in the cylinder center axis direction. Thereby, in the compression step, the vortex is generated by the new airflow flowing into the sub-combustion chamber from the main combustion chamber side, and the engine with the sub-combustion chamber that injects fuel from the injection hole provided at the front end in the sub-combustion chamber, When seeing through the fresh air flow from the viewpoint of the tip of the injection nozzle, at least in the range of the see-through shadow of the new air flow formed on the sub-combustion chamber wall, from the bottom wall to the ceiling wall via the side wall, One or more Center line of the serial injection holes, as passed in the state of extending, auxiliary combustion chamber with the engine, characterized in that the injection holes is disposed on the tip. ].

According to the first aspect of the present invention, when the new air flow is viewed through the viewpoint of the tip of the injection nozzle, the air is formed on the sub combustion chamber wall, from the bottom wall to the ceiling wall via the side wall. Injection holes are arranged at the tip so that the center line of at least one or more injection holes passes in an extended state within the range of the perspective of the new airflow, so fuel collides with the new airflow The fuel is injected in such a way that it is quickly mixed and ignited, and the ignitability and combustibility can be ensured. As a result, the generation of unburned gas in the low to medium speed range can be suppressed, and the NOx content in the exhaust gas can be further reduced.

According to a second aspect of the present invention, there is provided an apparatus having a plurality of communication holes, the opening of the other communication hole adjacent to the communication hole in the direction of the vortex when viewed in the cylinder central axis direction. 2. The engine with a sub-combustion chamber according to claim 1, wherein the engine is deviated in the vortex direction from the new airflow from the communication hole. 3. ].

According to the second aspect of the invention, when viewed in the cylinder center axis direction, the opening of the other communication hole adjacent to the communication hole in the vortex direction on the side of the sub-combustion chamber is less than the fresh air flow from the communication hole. Deviates in the vortex direction and passes behind the opening of the other communication hole on the side of the sub-combustion chamber, so that the new air flows do not interfere with each other and generate a sufficient vortex in the sub-combustion chamber to quickly mix the injected fuel. Then, it ignites and ignitability and flammability can be secured.

According to a third aspect of the present invention, there is provided a fuel cell system, comprising: a plurality of communication holes, the main combustion chamber-side opening and the sub-combustion chamber-side opening of the communication holes being located in the same direction as viewed in the cylinder center axis direction. The engine with a sub-combustion chamber according to claim 1 or 2, wherein the engine is shifted. ].

According to the third aspect of the invention, the opening of the communication hole on the main combustion chamber side and the opening on the sub combustion chamber side are displaced in the same direction as viewed in the cylinder center axis direction. A fast vortex is generated in the same direction without disturbing you,
The injected fuel is promptly mixed and ignited, and ignitability and combustibility can be ensured.

The invention according to claim 4 is characterized in that the number of the communication holes and the number of the injection holes are the same, and fuel is injected from each of the injection holes into a new airflow from each of the communication holes. The engine with a sub-combustion chamber according to any one of claims 1 to 3. ].

According to the fourth aspect of the present invention, the number of communication holes and the number of injection holes are the same, and fuel is injected from each injection hole to a new airflow from each communication hole. The mixed fuel is mixed more quickly and ignited,
It can ensure ignitability and flammability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine with a sub-combustion chamber according to the present invention will be described below with reference to the drawings. 1 is a longitudinal sectional view of an engine with a sub-combustion chamber, and FIG. 2 is II-II in FIG.
3 is a plan view of the sub-combustion chamber, FIG. 4 is a perspective view cut along the line IV-IV of FIG. 3, and FIG. 5 is a longitudinal sectional view of the sub-combustion chamber. .

Engine 1 with sub-combustion chamber of this embodiment
Is a water-cooled two-cylinder two-cycle diesel engine having a sub-combustion chamber. In the engine 1 with a sub-combustion chamber, a crankshaft 22 is supported by upper and lower crankcases 2 and 3, and a cylinder block 4 and a cylinder head 5 are mounted on the upper crankcase 3 in this order.

An exhaust pipe 7 is connected to the cylinder block 4 so as to communicate with an exhaust passage 6, and the exhaust pipes 7 of the respective cylinders are assembled on the downstream side. In the intake passage 8 of the upper crankcase 3,
A reed valve 9 is provided, and an intake pipe 10 is connected via the reed valve 9. The intake pipe 10 is formed so that an intake passage therein is branched for each cylinder, and a throttle valve device 1 is provided at an upstream end that is upstream of the branch portion.
1 and an unillustrated intake pipe, air cleaner and the like are connected.

The throttle valve device 11 has a structure in which a butterfly type throttle valve 11a is driven by a motor 11b. The motor 11b is controlled by the ECU 12 that controls the fuel injection amount and the oil supply amount of the engine 1 with the auxiliary combustion chamber. That is, a throttle opening corresponding to the engine speed detected by the engine speed detecting sensor 13 and the accelerator opening detected by the accelerator opening detecting sensor 14 is read from the map, and the read throttle opening and the throttle valve 11a are read. The motor 11b is driven such that the opening degrees coincide.

In the vicinity of the throttle valve device 11, a fuel injection pump 15 is arranged. This fuel injection pump 1
5 is driven by the engine 1 with a sub-combustion chamber to pump fuel to the fuel injection nozzle 16 for each cylinder. The amount of fuel supplied by the fuel injection pump 15 is controlled by the ECU 12. The fuel injection pump 15 is connected to the crankshaft 22.
The structure is such that the rotation is transmitted and driven.

The crankshaft 22 of the engine 1 with a sub-combustion chamber is connected to a piston 21 of each cylinder via a connecting rod 20.
Is linked to The piston 21 is slidably provided in a cylinder bore 4 a of the cylinder block 4. By assembling the crankshaft 22 and the upper and lower crankcases 2, 3, a crank chamber 23 for each cylinder is formed,
Air is sucked into these crank chambers 23 via the reed valve 9.

Further, a scavenging passage 2 communicating the crank chamber 23 with the inside of the cylinder bore 4a is provided in the cylinder block 4.
4 are formed. The scavenging passage 24 has a cylinder bore 4a.
, And communicates with the inside of the cylinder pore 4a via the main scavenging ports 24a, 24b and the sub-scavenging port 24c. The exhaust passage 6 has a main scavenging port 24.
The upstream side enters the cylinder bore 4a via one main exhaust port 6a having an upper edge slightly higher than the upper edge of the main exhaust port 6a and the sub exhaust port 6b opened at a position higher than the main exhaust port 6a. The downstream side communicates with the downstream side of the exhaust passage 6.

An exhaust control device 26 is provided in a portion of the exhaust passage 6 which communicates with the inside of the cylinder bore 4a via the auxiliary exhaust port 6b. The exhaust control device 26 is for changing the exhaust timing and the compression ratio, and is provided on the cylinder block 4 so as to be rotatable so as to cross the exhaust passage on the side of the auxiliary exhaust port 6b.
6a. The rod-shaped valve element 26a is closed when the engine rotation range is in the low / medium rotation range including the idling range, closes the exhaust passage portion, and is opened after the engine rotation range reaches the high rotation range, and the auxiliary exhaust valve 26a is closed. The ECU 12 controls the exhaust gas to be exhausted also from the passage portion.

When the rod-shaped valve body 26a is in the closed state,
The compression start timing is earlier and the exhaust start timing is later than in the open state, and the compression ratio is accordingly higher. Therefore, by closing the rod-shaped valve body 26a, the engine 1 with the sub-combustion chamber becomes easier to start due to an increase in the compression ratio, and the rotation becomes stable at low / medium rotation. Further, by opening the rod-shaped valve body 26a, a high output can be obtained due to a reduction in pumping loss during high rotation, an increase in the cross-sectional area of the exhaust passage, and a decrease in exhaust resistance.

The cylinder head 5 includes a cylinder block 4
A lower cylinder head 5a attached to the upper end of the cylinder head, a hot plug 5b attached to the lower cylinder head 5a, and an upper cylinder head 5c attached to the upper portions of the lower cylinder head 5a and the hot plug 5b. The upper wall of the main combustion chamber 27 is formed.

The lower cylinder head 5a is formed with a holding hole 28 having a small diameter portion and a large diameter portion.
b is held by being inserted into the holding hole 28 from above. The hot plug 5b is connected to the lower plug 5b1.
And an upper plug 5b2. The lower plug 5b1 has an upward concave portion 5b11, and the upper plug 5b2 has a downward concave portion 5b21.
The sub combustion chamber 30 is formed by 1 and the downward concave portion 5b21. The sub-combustion chamber 30 is formed in a flat cylindrical shape, and is located substantially on the center line of the cylinder bore 4a.

A pair of communicating holes 40 are formed in the lower plug 5b1 at symmetrical positions, and the main combustion chamber 27 and the main combustion chamber 2 are formed.
A combustion chamber is constituted by the sub-combustion chamber 30 communicated with 7 through a communication hole 40. The front end portion 16a of the fuel injection nozzle 16 faces the sub-combustion chamber 30, and fuel is injected from the injection hole 16b of the front end portion 16a into the new airflow 50 from the communication hole 40. Thereby, the sub-combustion chamber 30 is formed based on the new airflow 50.
The fine fuel can be mixed with the vortex 1000 generated inside. When the center line of the communication hole 40 is extended from the sub-combustion chamber side opening 40b provided on the inner bottom wall 30a1 of the sub-combustion chamber wall 30a, the center line is the upper half of the side wall 30a2 of the sub-combustion chamber wall 30a. Alternatively, the direction of the communication hole 40 is set so as to penetrate the outer peripheral portion of the ceiling 30a3.

The position of the main combustion chamber-side opening 40a and the position of the sub-combustion chamber-side opening 40b of the communication hole 40 are shifted from each other as viewed in the cylinder center axis direction. The vortex 1000 generated in the sub-combustion chamber 30 by the fresh air flow 50 from the communication hole 40 is
0b, the rectilinear portion 50a extending straight through the communication hole 40, and the rectilinear portion 50a is guided by the upper portion of the side wall 30a2 and the ceiling 30a3 or the ceiling 30a3.
And thereafter, the air is guided by the upper part of the side wall 30a2, becomes the slightly deflected flow part 50b along the side wall 30a2, and further becomes the vortex 1000 swirling around the center of the sub-combustion chamber wall 30a.

When the viewpoint is set at the tip 16a of the combustion injection nozzle 16 and the fresh air flow 50 is seen through, the shadow of the new air flow 50 is reflected on the sub-combustion chamber wall 30a. In the perspective shadow, the portion on the bottom wall 30a1 is the bottom wall shadow 100A, the portion on the side wall 30a2 in the perspective shadow is the sidewall shadow 100B, and the portion on the ceiling 30a3 in the perspective shadow is the sidewall shadow 100C. The extension of the injection hole center line L1 of the injection hole 16b provided at the tip end 16a of the fuel injection nozzle 16 is the auxiliary combustion chamber side opening 4
The direction of the injection hole 16b is set so as to pass through either the bottom wall shadow 100A or a part of the side wall shadow 100B reflected in the lower half of the side wall 30a2 while avoiding 0b.

As a result, at least half or more of the jet which is jetted and spread into a conical shape (or a polygonal pyramid or a star-shaped pyramid, etc.) while being miniaturized is at least a half of the straight stream portion 50a having a high internal velocity of the fresh air flow 50 or the deflected flow. It passes through the first part of 50 b and interferes with the new airflow 50. This allows
The fuel is further refined and quickly mixed into the fresh air stream 50 to become part of the vortex 1000. This improves ignitability and combustibility, while improving the fuel efficiency and startability while ensuring the fluidity of air and combustion gas, suppressing the generation of unburned gas in low to medium speed ranges, and further reducing exhaust emissions. NOx in gas
The content can be reduced.

The engine 1 with a sub-combustion chamber is started by rotating a crankshaft 22 by a starter motor (not shown). When the crankshaft 22 is rotated, air is sucked into the crank chamber 23 through an intake system including the throttle valve device 11, the intake pipe 10, the reed valve 9, and the intake passage 8, where it is compressed and scavenged to the scavenging passage 24, the scavenging port. It is introduced into the main combustion chamber 27 via 24a.

Then, in the compression stroke, the air in the main combustion chamber 27 flows into the sub-combustion chamber 30 through the communication hole 40, so that a fresh air flow 50 composed of air compressed in the sub-combustion chamber 30 and a vortex 1000 Is generated, and fuel is injected into the fresh air flow 50 from the injection holes 16b to ignite and start combustion. Thereafter, the combustion gas is blown out into the main combustion chamber 27 through the communication hole 40, and the piston 21 descends as the pressure in the main combustion chamber 27 rises. The combustion gas is discharged from the main combustion chamber 27 through the exhaust passage 6 to the exhaust pipe 7 by the piston 21 moving below the upper edge of the main exhaust port 6a or the auxiliary exhaust port 6b in the expansion stroke. .

The fresh air flow 50 has a flat shape in which the deflected flow portion 50b extends vertically along the side wall 3a2, while the sub-combustion chamber side opening 40b of the other communication hole 40 is deflected inward from the side wall 3a2. As a result, the interference between the deflected flow portion 50b and the fresh air flow 50 from the other communication hole 40 is reduced, and the eddy current is less likely to be weakened. Flammability can be ensured.

In the pair of communication holes 40, the main combustion chamber side opening 40a and the sub combustion chamber side opening 40b are displaced in the same direction when viewed in the direction of the cylinder center axis. A fast fresh air current and a vortex flow are generated in the same direction without being obstructed, and the injected fuel is quickly mixed and ignited, and ignitability and combustibility can be ensured.

Further, since the number of the communication holes 40 and the number of the injection holes 16b are the same, and the fuel is injected from each of the injection holes 16b to the fresh air flow 50 from each of the communication holes 40, the injected fuel can be quickly reduced. To ignite, ensuring ignitability and combustibility.

In the embodiment shown in FIG. 6, FIGS.
Four communication holes 40 configured in the same manner as in the embodiment are formed, and the number of the communication holes 40 and the number of the injection holes 16b of the fuel injection nozzle 16 are the same. The fuel injection nozzle 16 is
The nozzle axis L2 is disposed on the cylinder axis L3, and fuel is supplied from the nozzle axis direction. This fuel injection nozzle 1
6 may be arranged inclined as shown by a two-dot chain line,
The inclination can reduce the height of the engine.
When the fuel injection nozzle 16 is arranged obliquely, the fuel pipe is simple and easy by inclining it toward the fuel injection pump. FIG. 6B shows the lower plug 5.
FIG. 4 is a view of b1 as viewed from the upper side of the fuel injection nozzle 16;

As shown in FIG. 7, the fuel injection angle from the injection hole 16b of the fuel injection nozzle 16 can be set to an arbitrary position such as a position A to a position D, but is set to the position A. As a result, the fuel is injected into the portion of the new airflow 50 where the flow velocity is high, so that the fuel can be further miniaturized, the ignitability and the combustibility can be improved, and the output over the entire area and H
The emission of C, CO and black smoke is suppressed.

Further, as shown in FIG.
6, the direction angle of the central axis of the plurality of injection holes is 40 ° to 80 °, preferably 50 °, from the line drawn from the center of the sub-combustion chamber 30 to the sub-combustion chamber side opening 40b when viewed in the cylinder central axis direction.
° to 70 ° is set. Thereby, the injection hole 1 is formed in the straight portion 50a of the fresh air flow 50 from the sub-combustion chamber side opening 40b.
Since the jet flow from the nozzle 6b collides, the fuel spray and the air are well mixed, and the low-medium speed torque can be improved and the emission of NOx and black smoke can be suppressed.

In the embodiment shown in FIG. 9, the structure is the same as that of the embodiment shown in FIG. 6, but the side wall 3a of the auxiliary combustion chamber wall 30a is formed.
0a2, the connecting portion 30d of the bottom wall 30a1, the side wall 30a2
The radius of the connecting portion 30e of the ceiling and the ceiling 30a3 is made smaller than that of the embodiment of FIG. 6, and when the fresh air flow 50 changes from the straight traveling portion 50a to the deflected flow portion 50b, the fresh air flow 50 is disturbed,
The fine fuel mixed to zero can be mixed with the fresh air flow 50 more. In the case of a large radius as in the embodiment of FIG. 6, the fine fuel cannot be mixed with the fresh air flow 50, but even if the vortex 1000 is increased, the ignitability and combustibility of the fuel are reduced. Can be improved. FIG. 9B is a view in which the lower plug 5b1 is viewed from the upper side of the fuel injection nozzle 16.

In the embodiment shown in FIG. 10, the configuration is the same as that of the embodiment shown in FIG. 6, but the fuel supply port 16f of the fuel injection nozzle 16 is provided on the fuel injection pump side. Fuel is supplied from the fuel supply port 16f in a direction orthogonal to the nozzle axis direction, and the height of the engine can be reduced. In addition, the fuel injection nozzle 16 can be arranged to be inclined as shown by a two-dot chain line. In this case, the height of the engine can be further reduced. Further, by inclining the fuel injection nozzle 16 toward the fuel injection pump, the fuel pipe is simple and easy.

In the embodiment shown in FIG. 11, the structure is the same as that of the embodiment shown in FIG. 6, but the protrusion 5 of the upper plug 5b2 is formed.
A b22 surrounds the periphery of the tip 16a of the fuel injection nozzle 16 slightly projecting into the sub-combustion chamber 30. Projection 5b
22 improves the preservability of the vortex 1000, improves the use of air, and prevents overheating of the tip 16a due to the flame.

In the embodiment shown in FIG. 12, the structure is the same as that of the embodiment shown in FIG. 6. However, when viewed from the center axis direction of the cylinder, a method is used in which the center line of the communication hole 40 is drawn from the center of the auxiliary combustion chamber 30. The center of the sub-combustion chamber side opening 40b of the communication hole 40 is offset from the line. Thus, the auxiliary combustion chamber 3
The center of the sub-combustion chamber side opening 40b is offset with respect to the normal line while ensuring the deviation from the center of 0 to the center line of the communication hole 40.

By offsetting the communication holes 40 while maintaining the amount of deviation, the minimum cross-sectional area of the lower plug 5b1 between the adjacent communication holes 40 can be increased while maintaining the strength of the vortex, and the secondary combustion can be performed. The heat transfer from the center of the chamber 30 to the outer periphery can be improved, and the thermal deformation of the lower plug 5b1 can be suppressed.

In the embodiment shown in FIG. 13, the structure is the same as that of the embodiment shown in FIG. 6, but a projection 5b13 is provided at the center of the lower plug 5b1. The sub-combustion chamber side opening 40b of the communication hole 40 is provided on the bottom wall 30a1 outside the projection 5b13. The protrusion 5b13 suppresses thermal deformation of the lower plug 5b1, improves rigidity, improves vortex preservation, and improves air utilization.

In the sub-combustion chamber 30 in which the temperature rises as the piston 21 approaches the top dead center, the injected fuel is first ignited and combustion starts, and high-temperature general combustion gas and unburned gas pass through the communication hole 40. Then, the unburned gas flows into the main combustion chamber 27 and burns in the main combustion chamber 27. For this reason, the main combustion chamber 2 of the communication hole 40
The temperature of the piston 21 and the cylinder block 4 extending in the direction of extension to the 7 side becomes high. If the direction of extension of the communication hole 40 is on the exhaust side where the main and sub exhaust ports 6a and 6b are located, the exhaust side is a region that is exposed to the burned gas for a long time even in the sweeping and exhausting process, and is likely to become higher in temperature. In addition, the inside of the sub-combustion chamber 30 tends to become high temperature, and the upper plug 5b2 forming
The temperature of the lower plug 5b1 rises, and the temperature of the cylinder head 5 around both plugs tends to be high.

However, in the embodiment shown in FIG. 14, the structure is the same as that of the embodiment shown in FIG. 6, but the sub-combustion chamber 30 is arranged offset to the side opposite to the exhaust passage 6. Therefore, the lower plug 5b1 is cooled by the scavenging flow of the low-temperature fresh air in the scavenging and exhausting stroke, and the piston 21 and the cylinder block 4 are extended by an amount that the direction of extension from the communication hole 40 toward the main combustion chamber 27 approaches the scavenging port 24a. The temperature rise in the portion on the exhaust side is reduced. Thereby, the piston 21,
The temperature in the circumferential direction of the cylinder block 4 and the cylinder head 5 can be averaged, so that thermal deformation and lubricity can be improved.

The embodiment shown in FIG. 15 has the same configuration as the embodiment shown in FIG. 6, except that a recess 5b15 is formed on the lower plug 5b1 on the side of the main combustion chamber. After the start of combustion, the gas burned in the sub-combustion chamber 30 blows out from the communication hole 40 into the main combustion chamber 27. As a result, a vortex flows in the main combustion chamber 27 in the direction opposite to that of the sub-combustion chamber 30, and fresh air and unburned gas in the burned gas that has been ejected into the main combustion chamber 27 are remixed and re-burned, and , And HC, CO, black smoke and the like are reduced. FIG. 15B is a view of the lower plug 5b1 as viewed from the main combustion chamber 27 side.

In each of the embodiments described above, a two-cycle engine is used as the engine. However, a four-cycle engine can be equally applied. The upper plug 5
b2 is abolished, and the auxiliary combustion chamber wall 3 is removed by the cylinder head 5a.
0a may be formed.

[0049]

As described above, according to the first aspect of the present invention, when the fresh air flow is viewed through the viewpoint of the tip of the injection nozzle, the ceiling wall passes through the side wall from the bottom wall to the sub combustion chamber wall. Since the injection holes are arranged at the tip so that the center line of at least one or more injection holes is passed in an extended state within the range of the perspective of the new airflow formed over, the fuel is Since the fuel is injected in a form that collides with the new airflow, the injected fuel is quickly mixed and ignited, ignitability and combustibility can be ensured, and fuel efficiency can be improved while ensuring fluidity of air and combustion gas. It is possible to improve the startability, suppress the generation of unburned gas in the low to medium speed range, and further reduce the NOx content in the exhaust gas.

According to the second aspect of the present invention, when viewed in the central axis direction of the cylinder, the opening in the sub-combustion chamber of the other communication hole adjacent to the communication hole in the vortex direction is more eddy than the fresh air flowing from the communication hole. And the new air flow passes behind the opening of the other communication hole on the side of the auxiliary combustion chamber, so that the new airflows do not interfere with each other and generate a sufficient vortex in the auxiliary combustion chamber, causing the injected fuel to quickly mix and ignite And ignitability and flammability can be ensured.

According to the third aspect of the present invention, the opening of the communication hole on the main combustion chamber side and the opening on the sub combustion chamber side are displaced in the same direction when viewed in the direction of the cylinder center axis. A rapid vortex is generated in the same direction without being ignited, and the injected fuel is quickly mixed and ignited, and ignitability and combustibility can be ensured.

According to the fourth aspect of the present invention, the number of communication holes and the number of injection holes are the same, and fuel is injected from each injection hole into a fresh air flow from each communication hole. Ignited by mixing them more quickly, ensuring ignitability and combustibility.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine with a sub-combustion chamber.

FIG. 2 is a partial sectional view taken along the line II-II of FIG.

FIG. 3 is a plan view of a sub-combustion chamber.

FIG. 4 is a perspective view cut along line IV-IV of FIG. 3;

FIG. 5 is a vertical sectional view of a sub-combustion chamber.

FIG. 6 is a diagram showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 7 is a diagram illustrating a fuel injection angle.

FIG. 8 is a diagram illustrating mounting angles of a plurality of communication holes.

FIG. 9 is a diagram showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 10 is a diagram showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 11 is a view showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 12 is a diagram illustrating positions of communication holes according to another embodiment.

FIG. 13 is a diagram showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 14 is a view showing an engine with a sub-combustion chamber according to another embodiment.

FIG. 15 is a view showing an engine with a sub-combustion chamber according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine with sub combustion chamber 16 Fuel injection nozzle 16a Tip part 16b of fuel injection nozzle 16 Injection hole 27 Main combustion chamber 30 Sub combustion chamber 30a Sub combustion chamber wall 40 Communication hole 40a Main combustion chamber side opening 40b Sub combustion chamber side opening

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 61/14 310 F02M 61/14 310P 61/18 320 61/18 320Z

Claims (4)

[Claims] A combustion chamber is constituted by a main combustion chamber in a cylinder and a sub-combustion chamber provided in a cylinder head connected to the main combustion chamber through one or more communication holes. In the compression process, the position of the main combustion chamber-side opening and the sub-combustion chamber-side opening of the communication hole is shifted by viewing the communication hole in the cylinder center axis direction. In an engine with a sub-combustion chamber that generates a vortex by a new air flow flowing into the sub-combustion chamber from the chamber side and injects fuel from an injection hole provided at the front end into the sub-combustion chamber, a viewpoint is provided at the front end of the injection nozzle. At the time of seeing through the fresh air flow, at least one or more of the injection holes in the range of the see-through image of the new air flow formed from the bottom wall to the ceiling wall through the side wall on the sub-combustion chamber wall. Centerline is extended As passed in the state, the auxiliary combustion chamber with the engine, characterized in that the injection holes is disposed on the tip. 2. A communication device according to claim 2, wherein said communication hole has a plurality of communication holes, and the other communication hole adjacent to said communication hole in said vortex direction when viewed in a direction of a central axis of said cylinder has an opening on a sub combustion chamber side. The engine with a sub-combustion chamber according to claim 1, wherein the engine is deviated in the vortex direction from a new airflow. 3. A plurality of communication holes, wherein the openings of the communication holes on the main combustion chamber side and the auxiliary combustion chamber side are displaced in the same direction as viewed in the direction of the cylinder center axis. The engine with a sub-combustion chamber according to claim 1 or 2. 4. The fuel injection system according to claim 1, wherein the number of said communication holes is equal to the number of said injection holes, and fuel is injected from each of the injection holes into a new airflow from each of the communication holes. 4. The engine with a sub-combustion chamber according to any one of 3.