JP7652120B2 - engine - Google Patents

Description

This disclosure relates to engines.

Patent Document 1 discloses an internal combustion engine in which an auxiliary chamber is provided that is separated from the main chamber by a partition wall, a communication passage is formed in the partition wall that connects the main chamber and the auxiliary chamber, an ignition plug is disposed in the auxiliary chamber, and the mixture in the auxiliary chamber is ignited by the ignition plug, and the flame formed in the auxiliary chamber is ejected into the main chamber via the communication passage. In this internal combustion engine, a fuel injection valve is disposed in the main chamber, and fuel injected from the fuel injection valve into the main chamber and air in the main chamber flow into the auxiliary chamber via the communication passage, forming an air-fuel mixture in the auxiliary chamber.

JP 2004-204835 A

However, if the gas flow in the main chamber is strong, the fuel injected from the fuel injection valve (injection nozzle) may be diverted downstream. When the fuel injected from the fuel injection valve diverges downstream, it flows around to the other side of the partition and creates a fuel-rich mixture in the main chamber. When a fuel-rich mixture is created in part of the main chamber in this way, it is undesirable because it creates large amounts of nitrogen oxides (NOX).

In view of the above, at least one embodiment of the present invention aims to provide an engine that can reduce the amount of fuel that diverges downstream in the gas flow direction in the main chamber.

(1) An engine according to at least one embodiment of the present invention includes a piston, a cylinder block in which a cylinder in which the piston reciprocates is provided, a cylinder head fixed to the cylinder block and forming a main chamber between the piston and the cylinder block, a partition provided on the main chamber side of the cylinder head and forming a sub-chamber within the main chamber, an injection nozzle that injects fuel into the main chamber, and an ignition plug provided in the sub-chamber, the partition is provided on the injection nozzle side in the circumferential direction of the cylinder and has a fuel inflow communication passage leading from the main chamber to the sub-chamber and a fuel induction communication passage for guiding the fuel injected from the injection nozzle to the fuel inflow communication passage, the fuel induction communication passage leading from the main chamber to the sub-chamber upstream of the fuel inflow communication passage in the flow direction of gas in the main chamber.

According to the configuration of (1) above, the gas flowing through the fuel induction passage draws the fuel that is deflected downstream of the gas flow in the main chamber into the fuel inflow passage, so the amount of fuel that is deflected downstream of the gas flow can be reduced.

(2) In some embodiments, the maximum flow cross-sectional area of the fuel induction passage is smaller than the minimum flow cross-sectional area of the fuel inflow passage.

According to the configuration of (2) above, the flame injected from the fuel induction passage is weaker than the flame injected from the fuel inflow passage, so that the flame injected from the fuel induction passage can be prevented from overlapping with the flame injected from the fuel inflow passage and becoming significantly larger.

(3) In some embodiments, the fuel inflow passage is provided on an extension of the injection direction of the injection nozzle in the circumferential direction of the cylinder, and the fuel induction passage is provided at an angle to the fuel inflow passage.

According to the above configuration (3), the flame is injected from the fuel induction passage in a direction different from the direction of the flame injected from the fuel inflow passage, so that the flame injected from the fuel induction passage overlaps with the flame injected from the fuel inflow passage, preventing the flame from becoming significantly larger.

(4) In some embodiments, the partition wall surrounds the main chamber side opening of the fuel inflow passage and has a receiving surface that is flat or recessed from the partition wall toward the main chamber side opening of the fuel inflow passage.

According to the above configuration (4), the fuel injected from the injection nozzle collides with the receiving surface, so that the fuel injected from the injection nozzle can be prevented from missing the partition wall. This makes it possible to prevent a fuel-rich mixture from being generated in the main chamber.

(5) In some embodiments, the partition has a convex wall protruding from a main chamber side wall surface, and the convex wall surrounds the main chamber side opening of the fuel inflow passage and forms a receiving surface that is flat or that is recessed from an inner circumferential edge of the convex wall toward the main chamber side opening of the fuel inflow passage.

According to the above configuration (5), the fuel injected from the injection nozzle collides with the receiving surface, so that the fuel injected from the injection nozzle can be prevented from straying from the partition wall. This makes it possible to prevent a mixture containing a large amount of fuel from being generated in the main chamber.

According to at least one embodiment of the present invention, the gas flowing through the fuel induction passage draws the fuel that is deflected downstream due to the gas flow in the main chamber into the fuel inflow passage, thereby reducing the amount of fuel that is deflected downstream.

1 is a diagram illustrating a schematic diagram of an engine according to a first embodiment. FIG. 2 is a side cross-sectional view conceptually showing the cylinder and the partition wall shown in FIG. 1 . FIG. 2 is a cross-sectional plan view conceptually showing a cylinder and a partition wall shown in FIG. 1 . 4 is a cross-sectional plan view showing flame flows injected from a fuel inflow passage, a mixture inflow passage, and a fuel induction passage provided in a partition wall. FIG. FIG. 11 is a side cross-sectional view that shows a schematic diagram of a bulkhead of an engine according to a second embodiment. FIG. 11 is a side cross-sectional view that shows a schematic diagram of a bulkhead of an engine according to a third embodiment.

The following describes an embodiment of the present invention with reference to the attached drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described as the embodiment or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

[Embodiment 1]
[Overall engine configuration]
FIG. 1 is a cross-sectional view showing a schematic overall configuration of an engine 1A according to the first embodiment. As shown in FIG. 1, the engine 1A according to the first embodiment includes a piston 10, a cylinder block 12, a cylinder head 14, a partition wall 16, an injection nozzle 18, and an ignition plug 20. The cylinder block 12 is provided with a cylinder 22 in which the piston 10 reciprocates. The cylinder head 14 is fixed to the cylinder block 12, and forms a main chamber (combustion chamber) 24 between the piston 10 and the cylinder head 14. The cylinder head 14 is provided with an intake port 26 and an exhaust port 28. For example, two intake ports 26 and two exhaust ports 28 are provided for one main chamber 24, but this is not limited thereto. The intake port 26 is provided with an intake valve 30 for opening and closing the intake port 26, and the exhaust port 28 is provided with an exhaust valve 32 for opening and closing the exhaust port 28. For example, the intake port 26 is provided with an injection nozzle 34 (hereinafter referred to as a "port injector 34") that injects fuel, but the port injector 34 is not essential. The partition wall 16 is provided on the main chamber side of the cylinder head 14 and forms an auxiliary chamber (pre-combustion chamber) 36 within the main chamber. The injection nozzle 18 (hereinafter referred to as a "direct injector 18") injects fuel into the main chamber. The spark plug 20 is installed in the auxiliary chamber and is capable of igniting the air-fuel mixture that flows into the auxiliary chamber.

[Overall Operation of Engine 1A]
In the engine 1A according to the first embodiment, the port injector 34 injects fuel during the intake stroke when the intake valve 30 opens the intake port 26 and the piston 10 descends. As a result, an air-fuel mixture is supplied from the intake port 26 to the main chamber 24. In the engine 1A according to the first embodiment, the air-fuel mixture in the main chamber becomes a lean mixture having a leaner air-fuel ratio than the theoretical air-fuel ratio.

During the compression stroke when the intake valve 30 closes the intake port 26 and the piston 10 rises, the direct injector 18 injects fuel. As a result, the fuel injected from the direct injector 18 is supplied to the auxiliary chamber 36 together with the mixture in the main chamber. The mixture in the auxiliary chamber 36 is then ignited by the spark plug 20. In the engine 1A according to the first embodiment, the mixture in the auxiliary chamber 36 has an air-fuel ratio equivalent to the theoretical air-fuel ratio.

During the expansion stroke, which causes the piston 10 to descend, the mixture in the auxiliary chamber is ignited by the spark plug 20 and becomes a flame flow FF, which is injected into the main chamber, combusting the mixture in the main chamber.

During the exhaust stroke, when the exhaust valve 32 opens the exhaust port 28 and the piston 10 rises, the combustion gas in the main chamber is discharged. The engine 1A operates by repeating the intake stroke, compression stroke, expansion stroke, and exhaust stroke. In the engine 1A according to the first embodiment, the port injector 34 injects fuel during the intake stroke, but it may also be configured to inject fuel during the exhaust stroke. In this case, fuel is also supplied to the main chamber 24 during the intake stroke.

[Configuration of partition wall 16]
2 is a side cross-sectional view conceptually showing the cylinder 22 and the partition wall 16 shown in FIG. 1, and FIG. 3 is a plan cross-sectional view conceptually showing the cylinder 22 and the partition wall 16 shown in FIG.

As shown in FIG. 2, the partition wall 16 has an external shape that resembles a combination of a cylinder and a hemisphere, and a flange 38 is provided at the cylindrical end of the partition wall 16, which fixes the partition wall 16 to the main chamber side of the cylinder head 14. As a result, the cylindrical side of the partition wall 16 becomes the base end side that is fixed to the cylinder head 14, and the hemisphere side becomes the tip side located on the piston side. The partition wall 16 has an auxiliary chamber 36 inside that resembles a combination of a cylinder and a hemisphere. The cylindrical side of the auxiliary chamber 36 forms the auxiliary chamber base 40 located on the cylinder head side, and the hemisphere side forms the auxiliary chamber tip 42 located on the piston side.

The partition wall 16 has a fuel inflow communication passage 44 at its tip end that connects the main chamber 24 to the auxiliary chamber 36 (auxiliary chamber tip 42). As shown in FIG. 3, the fuel inflow communication passage 44 is provided on the direct injector side in the circumferential direction of the cylinder 22. The fuel inflow communication passage 44 is preferably provided in the injection range RG of the direct injector 18 in the circumferential direction of the cylinder 22, more preferably in a position directly opposite the injection direction of the direct injector 18 in the circumferential direction of the cylinder 22. When the fuel inflow communication passage 44 is provided in a position directly opposite the injection direction of the direct injector 18 in the circumferential direction of the cylinder 22, the fuel inflow communication passage 44 is provided on an extension of the injection direction of the direct injector 18 and extends straight toward the center of the auxiliary chamber 36. As shown in FIG. 2, the fuel inflow communication passage 44 is inclined toward the cylinder head 14 toward the inside (center) of the auxiliary chamber 36 so that the fuel FE injected from the direct injector 18 flows into the fuel inflow communication passage 44 during the compression stroke of the engine 1A, and more preferably, is provided along the injection direction of the direct injector 18. For example, there is one fuel inflow communication passage 44, but the number is not limited to one and may be two or more.

The partition wall 16 has at least one mixture inflow passage 46 on its tip side. The at least one mixture inflow passage 46 is a passage that leads from the main chamber 24 to the auxiliary chamber 36, similar to the fuel inflow passage 44, and is provided at a different position from the fuel inflow passage 44 in the circumferential direction of the cylinder 22, as shown in FIG. 3. The at least one mixture inflow passage 46 extends straight toward the center of the auxiliary chamber 36 in the circumferential direction of the cylinder 22, similar to the fuel inflow passage 44, but is not limited to this, and may be provided at an angle with respect to the direction toward the center of the auxiliary chamber 36. Also, as shown in FIG. 2, the at least one mixture inflow passage 46 is provided at an angle so as to approach the cylinder head 14 as it moves toward the inside of the auxiliary chamber 36, similar to the fuel inflow passage 44, and more preferably, is provided at an angle the same as the fuel inflow passage 44.

At least one mixture inflow passage 46 is two or more mixture inflow passages 46 that are arranged at equal intervals starting from the fuel inflow passage 44. For example, the partition wall 16 shown in FIG. 3 has five mixture inflow passages 46, but is not limited to this. The flow cross-sectional area of the mixture inflow passage 46 is preferably the same as the flow cross-sectional area of the fuel inflow passage 44, but is not limited to this.

2 and 3, the partition wall 16 has fuel induction communication passages 48, 50 at its tip end. The fuel induction communication passages 48, 50 are communication passages for guiding the fuel FE injected from the direct injector 18 toward the fuel inflow communication passage 44, and lead from the main chamber 24 to the auxiliary chamber 36 upstream of the fuel inflow communication passage 44 in the direction of gas flow in the main chamber.

As shown in FIG. 2, when a flow (tumble flow TF) in the extension direction of the cylinder 22 is formed in the main chamber, the fuel induction communication passage 48 is provided on the piston side that is upstream of the fuel inflow communication passage 44 in the flow direction of the tumble flow TF. The fuel induction communication passage 48 is provided at a position where the fuel FE flowing downstream of the fuel inflow communication passage 44 in the flow direction of the tumble flow TF during the compression stroke of the engine 1A can be guided toward the fuel inflow communication passage 44. The position where the fuel FE flowing downstream of the flow direction of the tumble flow TF can be guided toward the fuel inflow communication passage 44 is, for example, the injection range RG of the direct injector 18 in the extension direction of the cylinder 22. The position where the fuel FE flowing downstream of the flow direction of the tumble flow TF can be guided toward the fuel inflow communication passage 44 varies depending on the strength of the tumble flow TF, the injection timing of the fuel FE, the diameter of the fuel induction communication passage 48, etc., but can be determined by experiment or analysis.

As shown in FIG. 3, when a circumferential flow (swirl flow SF) of the cylinder 22 is formed in the main chamber, the fuel induction passage 50 is provided upstream of the fuel inflow passage 44 in the flow direction of the swirl flow SF. The flow direction of the swirl flow SF is determined by the shapes of the intake port 26 and the intake valve 30, and the opening and closing timing of the intake port 26, and is not limited to a clockwise flow, but may also be a counterclockwise flow. The fuel induction passage 50 is provided at a position where the fuel FE flowing downstream of the fuel inflow passage in the flow direction of the swirl flow SF can be guided toward the fuel inflow passage 44 during the compression stroke of the engine 1A. The position where the fuel FE flowing downstream of the flow direction of the swirl flow SF can be guided toward the fuel inflow passage 44 is, for example, the injection range RG of the direct injector 18 in the circumferential direction of the cylinder 22. The position where the fuel FE flowing downstream of the swirl flow SF can be guided toward the fuel inflow passage 44 varies depending on the strength of the swirl flow SF, the injection timing of the fuel FE, the diameter of the fuel guide passage 50, etc., but can be determined by experiment or analysis.

The fuel induction communication passages 48, 50 may be provided only upstream of the fuel inflow communication passage 44 in the flow direction of the tumble flow TF, or only upstream of the fuel inflow communication passage 44 in the flow direction of the swirl flow SF, as long as they are communication passages for guiding the fuel FE injected from the direct injector 18 toward the fuel inflow communication passage 44. In addition, they may be provided both upstream of the fuel inflow communication passage 44 in the flow direction of the tumble flow TF and upstream of the fuel inflow communication passage 44 in the flow direction of the swirl flow SF.

As shown in FIG. 4, the maximum flow cross-sectional area A1 of the fuel induction communication passage 48 is smaller than the minimum flow cross-sectional area A2 of the fuel inflow communication passage 44. For example, when the cross sections of the fuel induction communication passage 48 and the fuel inflow communication passage 44 are circular, the diameter of the fuel induction communication passage 48 is smaller than the diameter of the fuel inflow communication passage 44.

As described above, the fuel inflow passage 44 is provided on an extension of the injection direction of the direct injector 18 in the circumferential direction of the cylinder 22, and the fuel induction passage 48 is provided at an angle to the fuel inflow passage 44 in the circumferential direction of the cylinder 22.

[Operation of Engine 1A]
In the engine 1A according to the first embodiment described above, an air-fuel mixture is supplied into the main chamber during the intake stroke of the engine 1A, and a gas flow, for example, a tumble flow TF or a swirl flow SF is generated in the main chamber. The flow directions of the tumble flow TF and the swirl flow SF are determined by the shape of the intake port 26 and the opening and closing timing of the intake valve 30.

Next, the direct injector 18 injects fuel FE during the compression stroke of the engine 1A. The fuel FE injected from the direct injector 18 is deflected downstream of the fuel inflow passage 44 in the direction of the gas flow due to the gas flow in the main chamber, but the gas flowing through the fuel induction passages 48, 50 draws the fuel FE that is deflected downstream of the fuel inflow passage 44 into the fuel inflow passage 44. This creates a fuel-rich mixture around the main chamber side opening of the fuel inflow passage 44, and the fuel-rich mixture is supplied to the auxiliary chamber 36 through the fuel inflow passage 44.

For example, as shown in FIG. 2, when the flow in the main chamber is a tumble flow TF, the fuel FE injected from the direct injector 18 is deflected by the tumble flow TF in the direction of the tumble flow TF, downstream of the fuel inflow passage 44, but the gas flowing in the fuel induction passage 48 provided upstream of the fuel inflow passage 44 in the direction of the tumble flow TF draws the fuel FE that is deflected downstream of the fuel inflow passage 44 into the fuel inflow passage 44. As a result, a fuel-rich mixture is generated around the main chamber side opening of the fuel inflow passage 44, and the fuel FE-rich mixture is supplied to the auxiliary chamber 36 through the fuel inflow passage 44.

Similarly, for example, as shown in FIG. 3, when the flow in the main chamber is a swirl flow SF, the fuel FE injected from the direct injector 18 is deflected by the swirl flow SF in the direction of the swirl flow SF, downstream of the fuel inflow passage 44, but the gas flowing in the fuel induction passage 50 provided upstream of the fuel inflow passage 44 in the direction of the swirl flow SF draws the fuel FE that is deflected downstream of the fuel inflow passage 44 into the fuel inflow passage 44. As a result, a fuel-rich mixture is generated around the main chamber side opening of the fuel inflow passage 44, and the fuel-rich mixture is supplied to the auxiliary chamber 36 through the fuel inflow passage 44.

Next, during the expansion stroke of engine 1A, the spark plug ignites the rich fuel mixture in the pre-chamber. The mixture in the pre-chamber then turns into a flame, which passes through the fuel inflow passage 44, the mixture inflow passage 46, and the fuel induction passages 48 and 50 and is injected into the main chamber, combusting the mixture in the pre-chamber.

[effect]
According to the engine 1A of the first embodiment described above, during the compression stroke, the gas flowing through the fuel induction communication passages 48, 50 attracts the fuel FE that is deflected downstream of the gas due to the gas flow in the main chamber to the fuel inflow communication passage 44, so that the amount of fuel FE that is deflected downstream of the gas can be reduced.

As shown in FIG. 4, the maximum flow cross-sectional area A2 of the fuel induction communication passage 48 is smaller than the minimum flow cross-sectional area A1 of the fuel inflow communication passage 44, so that the flame injected from the fuel induction communication passage 48 during the expansion stroke is weaker than the flame injected from the fuel inflow communication passage 44. This prevents the flame injected from the fuel induction communication passage 48 from overlapping with the flame injected from the fuel inflow communication passage 44, resulting in a significantly larger flame.

As shown in FIG. 4, the fuel induction passage 48 is inclined relative to the fuel inflow passage 44, so that the flame is injected from the fuel induction passage 48 in a direction different from the direction of the flame injected from the fuel inflow passage 44 during the expansion stroke. This prevents the flame injected from the fuel induction passage 48 from overlapping with the flame injected from the fuel inflow passage 44, resulting in a significantly larger flame.

[Embodiment 2]
[Engine configuration]
Fig. 5 is a side cross-sectional view that shows a schematic view of the partition 16 of the engine 1B according to the second embodiment. As shown in Fig. 5, the partition 16 has a recess 52 recessed from the main chamber side wall surface of the partition 16 on the tip side thereof. An outer peripheral edge 52a of the recess 52 surrounds the main chamber side opening 44a of the fuel inflow communication passage 44 and the main chamber side opening 48a of the fuel induction communication passage 48, and the recess 52 forms a receiving surface 54 recessed from the outer peripheral edge 52a of the recess 52 toward the main chamber side opening 42a of the fuel inflow communication passage 44. The receiving surface 54 is not limited to being recessed from the outer peripheral edge 52a of the recess 52 toward the main chamber side opening 44a of the fuel inflow communication passage 44, and may be flat. The receiving surface 54 recessed from the outer circumferential edge 52a of the recess 52 toward the main chamber side opening 42a of the fuel inflow communication passage 44 is a curved surface whose periphery is the outer circumferential edge 52a of the recess 52, and for example, the main chamber side opening 44a of the fuel inflow communication passage 44 is provided at the recessedmost position. The other configurations are the same as those of the engine 1A according to the first embodiment.

[Operation of Engine 1B]
In the engine 1B according to the second embodiment described above, the direct injector 18 injects fuel FE during the compression stroke of the engine 1B. The fuel FE injected from the direct injector 18 is deflected in the gas flow direction and downstream of the fuel inflow communication passage 44 by the gas flow in the main chamber, but the gas flowing in the fuel induction communication passage 48 draws the fuel FE that is deflected downstream of the fuel inflow communication passage 44 into the fuel inflow communication passage 44. As a result, the fuel FE drawn into the fuel inflow communication passage 44 collides with the receiving surface 54 formed on the inside of the recess 52, and a fuel-rich mixture is generated around the main chamber side opening 44a of the fuel inflow communication passage 44. As a result, the fuel-rich mixture is supplied to the auxiliary chamber 36 through the fuel inflow communication passage 44. The other operations are the same as those of the engine 1A according to the first embodiment.

In the engine 1B according to the second embodiment described above, the gas flowing through the fuel induction passage 48 draws the fuel FE that deviates downstream of the fuel inflow passage 44 back into the fuel inflow passage 44, and the fuel FE injected from the direct injector 18 collides with the receiving surface 54, so that the fuel FE injected from the direct injector 18 can be prevented from deviating from the partition wall 16. This makes it possible to prevent a mixture containing a large amount of fuel FE from being generated in the main chamber.

[Embodiment 3]
[Engine configuration]
Fig. 6 is a side cross-sectional view that shows a schematic view of the partition 16 of the engine 1C according to the third embodiment. As shown in Fig. 6, the partition 16 has a protruding wall 56 that protrudes from the main chamber side wall surface 16a of the partition 16 on the tip side thereof. The protruding wall 56 surrounds the main chamber side opening 44a of the fuel inflow communication passage 44 and the main chamber side opening 48a of the fuel induction communication passage 48, and forms a receiving surface 58 that is recessed from an inner peripheral edge 56a of the protruding wall 56 toward the main chamber side opening 44a of the fuel inflow communication passage 44. The receiving surface 58 is not limited to being recessed from the inner peripheral edge 56a of the protruding wall 56 toward the main chamber side opening 44a of the fuel inflow communication passage 44, and may be flat. The receiving surface 58 recessed from the inner circumferential edge 56a of the convex wall 56 toward the main chamber side opening 44a of the fuel inflow communication passage 44 is a curved surface whose periphery is the inner circumferential edge 56a of the convex wall 56, and for example, the main chamber side opening 44a of the fuel inflow communication passage 44 is provided at the most recessed position. The other configurations are the same as those of the engine 1A according to the first embodiment.

[Operation of Engine 1C]
In the engine 1C according to the third embodiment described above, the direct injector 18 injects fuel FE during the compression stroke of the engine 1C. The fuel FE injected from the direct injector 18 is deflected in the gas flow direction and downstream of the fuel inflow communication passage 44 by the gas flow in the main chamber, but the gas flowing in the fuel induction communication passage 48 draws the fuel FE that is deflected downstream of the fuel inflow communication passage 44 into the fuel inflow communication passage 44. As a result, the fuel FE drawn into the fuel inflow communication passage 44 collides with the receiving surface 58 formed on the inner side of the convex wall 56, and a fuel-rich mixture is generated around the main chamber side opening of the fuel inflow communication passage 44. As a result, the fuel-rich mixture is supplied to the auxiliary chamber 36 through the fuel inflow communication passage 44. The other operations are the same as those of the engine 1A according to the first embodiment.

According to the engine 1C according to the third embodiment described above, the gas flowing through the fuel induction passage 48 draws the fuel FE that deviates downstream of the fuel inflow passage 44 back into the fuel inflow passage 44, and the fuel FE injected from the direct injector 18 collides with the receiving surface 58, so that the fuel FE injected from the direct injector 18 can be prevented from deviating from the partition wall 16. This makes it possible to prevent a mixture containing a large amount of fuel from being generated in the main chamber.

1A, 1B, 1C Engine 10 Piston 12 Cylinder block 14 Cylinder head 16 Partition wall 16a Main chamber side wall surface 18 Injection nozzle (direct injector)
20 Spark plug 22 Cylinder 24 Main chamber (combustion chamber)
26 Intake port 28 Exhaust port 30 Intake valve 32 Exhaust valve 34 Injection nozzle (port injector)
36 Auxiliary combustion chamber (pre-combustion chamber)
Reference Signs List 38 Flange 40 Auxiliary chamber base 42 Auxiliary chamber tip 44 Fuel inflow passage 44a Main chamber side opening 46 Mixture inflow passage 48, 50 Fuel induction passage 48a Main chamber side opening 52 Recess 52a Outer periphery 54 Receiving surface 56 Convex wall 56a Inner periphery 58 Receiving surface FE Fuel FF Flame flow RG Injection range of direct injector TF Tumble flow SF Swirl flow A1 Maximum flow path cross-sectional area A2 of fuel induction passage Minimum flow path cross-sectional area of fuel inflow passage

Claims (5)

The piston and
a cylinder block provided with a cylinder in which the piston reciprocates;
a cylinder head fixed to the cylinder block and defining a main chamber between the cylinder head and the piston;
a partition wall provided on the main chamber side of the cylinder head and defining an auxiliary chamber within the main chamber;
an injection nozzle that injects fuel into the main chamber;
an ignition plug provided in the sub-chamber;
The partition wall is
a fuel inflow passage provided on the injection nozzle side in the circumferential direction of the cylinder and communicating from the main chamber to the auxiliary chamber;
a fuel guide passage for guiding the fuel injected from the injection nozzle to the fuel inflow passage,
the fuel induction communication passage communicates from the main chamber to the auxiliary chamber upstream of the fuel inflow communication passage in a gas flow direction in the main chamber;
engine. The engine of claim 1, wherein the maximum flow cross-sectional area of the fuel induction passage is smaller than the minimum flow cross-sectional area of the fuel inflow passage. the fuel inflow communication passage is provided on an extension line of the injection direction of the injection nozzle in the circumferential direction of the cylinder,
3. The engine according to claim 1, wherein the fuel induction passage is inclined with respect to the fuel inflow passage. 4. The engine according to claim 1, wherein the partition wall surrounds an opening of the fuel inflow passage on the main chamber side and has a receiving surface that is flat or recessed from the partition wall toward the opening of the fuel inflow passage on the main chamber side . The partition wall has a protruding wall protruding from a main chamber side wall surface,
4. The engine according to claim 1, wherein the convex wall surrounds an opening of the fuel inflow passage on a main chamber side and forms a receiving surface that is flat or that is recessed from an inner circumferential edge of the convex wall toward the opening of the fuel inflow passage on a main chamber side.

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