Engine system

Abstract

An engine system suppresses knocking sound of an engine. The engine system (1) includes: a combustion chamber (34) formed in a cylinder (30); and a supply portion (14) that supplies air to a peripheral region around an inner peripheral surface (36) of the cylinder (30) in the combustion chamber (34). The supply portion (14) causes rich mixture gas present in the combustion chamber (34) to gather to a central region in the combustion chamber (34) by supplying air to the peripheral region before ignition, and forms a stratified structure composed of a mixture gas layer of the central region and an air layer of the peripheral region.

Description

Technical Field

[0001] This invention relates to an engine system having an engine. Background Technology

[0002] For example, Patent Document 1 discloses an example of an engine system designed to prevent engine knocking. Furthermore, knocking is also known as detonation.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2004-3428 Summary of the Invention

[0004] In the technology of Patent Document 1, high-pressure air is injected into the combustion chamber in conjunction with the ignition timing of the gas-fuel mixture, generating turbulence within the combustion chamber. Thus, the technology of Patent Document 1 increases the combustion rate in the later stages of combustion, thereby suppressing knocking noise. However, even with the technology of Patent Document 1, knocking noise cannot be sufficiently suppressed. Therefore, there is a need for more appropriate suppression of knocking noise.

[0005] Therefore, the object of the present invention is to provide an engine system capable of suppressing engine knock noise.

[0006] To address the aforementioned issues, the engine system of the present invention includes: a combustion chamber formed within a cylinder; and an air supply unit that supplies air to a peripheral region surrounding the inner circumferential surface of the cylinder within the combustion chamber. By supplying air to the peripheral region before ignition, the air supply unit causes the fuel-rich mixture present in the combustion chamber to accumulate in a central region within the combustion chamber, forming a layered structure consisting of a fuel-rich mixture layer in the central region and an air layer in the peripheral region.

[0007] Alternatively, the engine system may have a gap between the cylinder block that forms the cylinder and the cylinder head that is disposed on the cylinder block in a manner that blocks the cylinder. The gap communicates with the combustion chamber, and the air supply section communicates with the gap and supplies air to the surrounding area through the gap.

[0008] According to the present invention, engine knocking noise can be suppressed. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the structure of the engine system according to this embodiment.

[0010] Figure 2 This is a perspective top view of the cylinder head and combustion chamber, viewed from above.

[0011] Figure 3 It is a diagram illustrating the timing of the high-pressure air supply.

[0012] Figures 4A-4E This is a diagram illustrating the conditions inside the combustion chamber.

[0013] (Explanation of reference numerals in the attached diagram)

[0014] 1 Engine System

[0015] 14 Gas Supply Department

[0016] 20 cylinder block

[0017] 24 Cylinder head

[0018] 30 cylinders

[0019] 34 Combustion Chamber

[0020] 36 Inner circumferential surface

[0021] 40 Gap section Detailed Implementation

[0022] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in these embodiments are merely illustrative for ease of understanding and are not intended to limit the invention, except where specifically excluded. Furthermore, in this specification and the accompanying drawings, elements having substantially the same function or structure are labeled with the same reference numerals, thereby omitting redundant descriptions; additionally, elements not directly related to the present invention are omitted from the illustrations.

[0023] Figure 1 This is a schematic diagram showing the structure of the engine system 1 according to this embodiment. The engine system 1 is applied, for example, to a hybrid vehicle or a motor vehicle. The engine system 1 includes an engine 10, an engine control unit 12, and an air supply unit 14. The engine 10 includes a cylinder block 20, a piston 22, a cylinder head 24, an intake valve 26, and an exhaust valve 28.

[0024] Multiple cylinders 30 are formed in the cylinder block 20. A piston 22 is slidably housed within a cylinder 30. The piston 22 is connected to a crankshaft (not shown) via a connecting rod 32. The crankshaft rotates with the reciprocating motion of the piston 22.

[0025] The cylinder head 24 is located on the side of the cylinder block 20 opposite to the crankshaft. The cylinder head 24 is mounted on the cylinder 30 in a manner that blocks the cylinder 30 and is connected to the cylinder block 20. A combustion chamber 34 is formed inside the cylinder 30. Specifically, the combustion chamber 34 is formed by the inner peripheral surface 36 of the cylinder 30, the top surface of the piston 22, and the inner surface of the cylinder head 24.

[0026] A gap 40 is formed between the cylinder block 20 and the cylinder head 24. The gap 40 is an annular plate-shaped space, positioned around the combustion chamber 34 and communicating with it. A gasket 42 is disposed on the outer side of the gap 40 between the cylinder block 20 and the cylinder head 24. The gasket 42 is held between the cylinder block 20 and the cylinder head 24. The gap 40 is blocked by the gasket 42.

[0027] An intake port 50 and an exhaust port 52 are formed in the cylinder head 24. The intake port 50 and the exhaust port 52 are connected to the combustion chamber 34.

[0028] An intake valve 26 is located at the intake port 50. The valve core of the intake valve 26 is located at the opening on the combustion chamber 34 side of the intake port 50. The base of the intake valve 26 abuts against the intake cam 54. The intake cam 54 is connected to the intake camshaft 56. The intake camshaft 56 rotates in conjunction with the crankshaft. The intake cam 54 rotates in conjunction with the intake camshaft 56. The intake valve 26 opens or closes the intake port 50 as the intake cam 54 rotates. When the intake port 50 is opened by the intake valve 26, air is supplied to the combustion chamber 34 through the intake port 50.

[0029] An exhaust valve 28 is located at the exhaust port 52. The valve core of the exhaust valve 28 is located at the opening on the combustion chamber 34 side of the exhaust port 52. The base of the exhaust valve 28 abuts against the exhaust cam 58. The exhaust cam 58 is connected to the exhaust camshaft 60. The exhaust camshaft 60 rotates in conjunction with the crankshaft. The exhaust cam 58 rotates in conjunction with the exhaust camshaft 60. The exhaust valve 28 opens and closes the exhaust port 52 as the exhaust cam 58 rotates. When the exhaust port 52 is opened by the exhaust valve 28, the gas in the combustion chamber 34 is expelled through the exhaust port 52.

[0030] An injector 62 and a spark plug 64 are disposed in the cylinder head 24. The injector 62 and spark plug 64 are located near the central axis of the cylinder 30. The injector 62 is configured with its injection port facing the combustion chamber 34. The injector 62 injects fuel such as gasoline into the combustion chamber 34 at predetermined intervals. The spark plug 64 is configured with its electrode facing the combustion chamber 34. The spark plug 64 ignites the air-fuel mixture at predetermined intervals, causing it to burn. Through this combustion, the piston 22 reciprocates within the cylinder 30.

[0031] The engine control unit 12 is composed of semiconductor integrated circuits including a central processing unit, a ROM (Read Only Memory) storing programs, and RAM (Random Access Memory) as the working area. The engine control unit 12 controls various parts of the engine 10 by executing programs. For example, the engine control unit 12 controls the fuel injection timing of the injector 62 and the ignition timing of the spark plug 64. Additionally, as described later, the engine control unit 12 also performs controls related to the air supply unit 14.

[0032] The air supply unit 14 includes an air pressurization pump 70, an air common rail 72, an air piping 74, an air port 76, an air cavity 78, a connecting hole 80, and a moving valve mechanism 82.

[0033] The air booster pump 70 includes a pump body 90 and a pressurizing mechanism 92. An inlet pipe 96 is connected to the inlet 94 of the pump body 90. The inlet pipe 96 is, for example, connected to an intake pipe between an air filter (not shown) and a throttle valve. Air that has passed through the air filter is supplied to the pump body 90 through the inlet pipe 96. Alternatively, the inlet pipe 96 can be connected to a filter different from the air filter of the intake pipe. In this case, air obtained separately from the intake air that has passed through the intake pipe is supplied to the pump body 90 through the inlet pipe.

[0034] The pressurizing mechanism 92 pressurizes the air introduced into the pressurizing chamber of the pump body 90 through the inlet pipe 96, and sends the pressurized air out of the outlet 98 of the pump body 90. Hereinafter, the pressurized air will sometimes be referred to as high-pressure air or simply as air.

[0035] Specifically, the pressurization mechanism 92 includes a pump cam 100 and a plunger 102. The pump cam 100 is connected to and rotates in conjunction with the intake camshaft 56. The base end of the plunger 102 abuts against the pump cam 100. The front end of the plunger 102 is inserted into the pressurization chamber within the pump body 90. The plunger 102 slides in conjunction with the rotation of the pump cam 100, pressurizing the air in the pressurization chamber.

[0036] Multiple pump cams 100 of different shapes or sizes can be provided in the pressurization mechanism 92. In this case, the engine control unit 12 switches the pump cams 100 that abut against the plunger 102 according to the operating state such as the throttle opening. This allows for changes in the air pressurization level or pressurization timing. Furthermore, the engine control unit 12 can advance or delay the intake camshaft 56. Since the pump cams 100 are connected to the intake camshaft 56, the phase changes according to the advance or delay of the intake camshaft 56. This allows for changes in the air pressurization timing.

[0037] Furthermore, the pump cam 100 is not limited to being linked to the intake camshaft 56. For example, the pump cam 100 can be linked to the exhaust camshaft 60. In this case, the air pressurization timing can be changed according to the advance or retardation of the exhaust camshaft 60. Alternatively, the pump cam 100 can be linked to a separate camshaft, different from both the intake camshaft 56 and the exhaust camshaft 60. In this case, the air pressurization timing can be changed according to the advance or retardation of this separate camshaft.

[0038] The common air rail 72 is formed, for example, in a tubular shape and is connected to the outlet 98 of the pump body 90. The common air rail 72 is disposed on the cylinder head 24 and extends to multiple cylinders 30. The common air rail 72 is capable of maintaining the pressure of the high-pressure air delivered from the outlet 98 of the pump body 90 to accumulate pressure.

[0039] An opening 110 is formed on the side of the common air rail 72. An air pipe 74 is connected to the opening 110. The air pipe 74 is connected to an air port 76 formed in the cylinder head 24. The air port 76 is formed separately from the intake port 50 and the exhaust port 52. The air port 76 communicates with an air cavity 78 formed in the cylinder head 24. The air cavity 78 is located above the clearance portion 40. A connecting hole 80 extends downward from the air cavity 78, connecting the air cavity 78 and the clearance portion 40. Thus, the air supply portion 14 communicates with the clearance portion 40.

[0040] Figure 2 This is a perspective top view of the cylinder head 24 and combustion chamber 34, viewed from above. (Example) Figure 2 As shown, the air cavity 78 is formed in an annular shape surrounding the outer side of the combustion chamber 34. An air inlet 76 penetrates any position on the outer peripheral surface of the air cavity 78. Multiple connecting holes 80 are formed dispersedly in the circumferential direction of the air cavity 78. For example, eight connecting holes 80 are formed at equal intervals in the circumferential direction of the air cavity 78. Furthermore, the number and position of the connecting holes 80 are not limited to... Figure 2 The example shown can be designed appropriately.

[0041] return Figure 1 The actuated valve mechanism 82 includes an air valve 120 and an air cam 122. The valve core of the air valve 120 is located at the opening 110, to which an air pipe 74 in the common air rail 72 is connected. The base of the air valve 120 abuts against the air cam 122. The air cam 122 is connected to and rotates in conjunction with the intake camshaft 56. The rotation of the air valve 120 and the air cam 122 causes the opening 110 of the common air rail 72 to open and close.

[0042] When the opening 110 is closed by the air valve 120, high-pressure air is not supplied to the air pipe 74. On the other hand, when the opening 110 is opened by the air valve 120, a portion of the high-pressure air in the common air rail 72 is supplied to the air pipe 74 through the opening 110. The high-pressure air supplied to the air pipe 74 is supplied to the clearance section 40 through the air pipe 74, air port 76, air chamber 78, and connecting hole 80. Then, the high-pressure air in the clearance section 40 is supplied to the combustion chamber 34 located radially inside the clearance section 40.

[0043] That is, the air supply section 14 supplies air to the peripheral area around the inner circumferential surface 36 of the cylinder 30 in the combustion chamber 34 through the gap section 40.

[0044] Multiple air cams 122 of different shapes or sizes can be provided in the valve mechanism 82. In this case, the engine control unit 12 switches the air cams 122 that abut against the air valve 120 according to the operating state such as the throttle opening. This allows for changes in the air supply quantity or timing. Furthermore, the engine control unit 12 can advance or delay the intake camshaft 56. Since the air cams 122 are connected to the intake camshaft 56, the phase changes according to the advance or delay of the intake camshaft 56. This allows for changes in the air supply timing.

[0045] Furthermore, the air cam 122 is not limited to being linked to the intake camshaft 56. For example, the air cam 122 can be linked to the exhaust camshaft 60. In this case, the air supply timing can be changed according to the advance or delay of the exhaust camshaft 60. Alternatively, the air cam 122 can be linked to a separate camshaft, different from both the intake camshaft 56 and the exhaust camshaft 60. In this case, the air supply timing can be changed according to the advance or delay of this separate camshaft.

[0046] As described above, high-pressure air generated by the air booster pump 70 is supplied to the combustion chamber 34. Accordingly, the pressure inside the combustion chamber 34 when high-pressure air is supplied to the combustion chamber 34 is set as a reference pressure. The air booster pump 70 generates high-pressure air with a pressure higher than this reference pressure and a pressure difference between the two pressures within a predetermined range. In other words, the pressure of the high-pressure air is set to be slightly higher than the reference pressure inside the combustion chamber 34.

[0047] The pressure of the high-pressure air is higher than the reference pressure inside the combustion chamber 34, so the air supply unit 14 can supply high-pressure air to the combustion chamber 34. Furthermore, since the pressure difference between the high-pressure air and the reference pressure inside the combustion chamber 34 is within a predetermined range, the flow velocity of the high-pressure air supplied from the gap 40 to the combustion chamber 34 is relatively low, and turbulence is not generated in the gas-fuel mixture inside the combustion chamber 34. This predetermined range of pressure difference is set to a small range that is considered to prevent turbulence; the reference pressure inside the combustion chamber 34 can be appropriately set.

[0048] Furthermore, by preventing turbulence, the air supply unit 14 can retain the high-pressure air supplied to the combustion chamber 34 in the peripheral area around the inner circumferential surface 36 of the cylinder 30 within the combustion chamber 34. The function of the high-pressure air will be explained in detail later.

[0049] Figure 3 This diagram illustrates the timing of the high-pressure air supply. Engine 10 repeatedly performs the intake stroke, compression stroke, expansion stroke, and exhaust stroke in that order. The intake stroke occurs during the movement of piston 22 from top dead center to bottom dead center. The compression stroke occurs after the intake stroke, during the movement of piston 22 from bottom dead center to top dead center. The expansion stroke occurs after the compression stroke, during the movement of piston 22 from top dead center to bottom dead center. Although not shown in the diagram, the exhaust stroke occurs after the expansion stroke, during the movement of piston 22 from bottom dead center to top dead center.

[0050] Engine 10 draws in air through intake port 50 during the intake stroke. Engine control unit 12, as shown... Figure 3 As shown in the cross-sectional area A10, fuel is injected from the injector 62 during the intake stroke. As a result, a mixture of the intake air from the intake stroke and the fuel injected by the injector 62 is generated in the combustion chamber 34. Figure 3 The timing TA indicates the timing for switching from the intake stroke to the compression stroke.

[0051] When the stroke transitions to the compression stroke, as the piston 22 rises, the air-fuel mixture in the combustion chamber 34 is compressed, and the cylinder pressure, which indicates the pressure inside the combustion chamber 34, increases. Then, at the predetermined timing TC at the end of the compression stroke, the engine control unit 12 ignites the air-fuel mixture with the spark plug 64.

[0052] Here, as Figure 3 As shown in the cross-sectional area A12, before the gas mixture is ignited by the spark plug 64, the gas supply unit 14 supplies air (i.e., high-pressure air) to the combustion chamber 34 through the gap 40.

[0053] Specifically, the air supply start timing of the air supply unit 14 is between the fuel injection end timing and the ignition timing (i.e., timing TC). Before the predetermined time of the ignition timing, the air supply unit 14 begins to supply high-pressure air by opening the opening 110 of the air valve 120. The engine control unit 12 can perform operations such as switching the air cam 122 of the actuator valve mechanism 82 to ensure that the air supply start timing of the air supply unit 14 is appropriate.

[0054] Figure 3The timing TB indicates the end timing of the air supply to the air supply unit 14. The end timing of the air supply to the air supply unit 14 is before the ignition timing (i.e., timing TC). In addition, as long as the start timing of the air supply to the air supply unit 14 is at least before the ignition timing, the end timing of the air supply to the air supply unit 14 can be after the ignition timing.

[0055] Thus, the combustion chamber 34 contains a mixture of intake air and fuel during the intake stroke, and high-pressure air supplied by the air supply unit 14. Therefore, in the engine 10, the intake air volume, fuel injection volume, and high-pressure air supply are adjusted so that the total gas mixture of intake air and fuel, and high-pressure air, is ideally stoichiometric. In other words, taking into account the high-pressure air, a fuel-rich mixture is prepared with the proportion of intake air and fuel as fuel being as high as possible relative to the ideal stoichiometric ratio.

[0056] More specifically, regarding the fuel-rich mixture of intake air and fuel, the ratio of fuel to air is approximately 1.1. In other words, if the amount of air that will be ideally mixed is set to 100%, then 90% of the amount of air that will be ideally mixed is the air generated by intake air, and 10% of the amount of air that will be ideally mixed is the air supplied by the air supply unit 14.

[0057] The engine control unit 12 determines the ideal air volume and fuel injection quantity based on operating conditions such as throttle opening. Based on the ideal air volume, the engine control unit 12 determines the amount of high-pressure air supplied by the air supply unit 14. Based on the high-pressure air volume, the engine control unit 12 determines the high-pressure air supply start timing. The engine control unit 12 performs adjustments such as switching the air cam 122 to ensure that the high-pressure air supply begins at the determined start timing.

[0058] like Figure 3 As shown, when the gas mixture is ignited, the flame spreads, and the heating rate within the combustion chamber 34 increases. Furthermore, the heating rate decreases after reaching its peak. Figure 3 The timing TD indicates the timing at which the heating rate reaches its peak. Figure 3 The timing TE indicates the timing of combustion diffusion throughout the entire gas mixture.

[0059] Figure 4~ Figure 4E This is a diagram illustrating the conditions inside combustion chamber 34. Figure 4A Show Figure 3 The situation inside combustion chamber 34 during timed TA. Figure 4B Show Figure 3 The condition inside the combustion chamber 34 when the timing TB is reached. Figure 4C Show Figure 3 The condition inside combustion chamber 34 during timed TC. Figure 4D Show Figure 3 The condition inside combustion chamber 34 during timed TD. Figure 4E Show Figure 3 The situation inside combustion chamber 34 during the timing TE.

[0060] like Figure 4A As shown in section A20, during timing TA, the combustion chamber 34 is filled with a fuel-rich mixture of intake air and fuel. In this state, high-pressure air is then supplied to the combustion chamber 34 by the air supply unit 14.

[0061] High-pressure air is supplied to the peripheral region around the inner circumferential surface 36 of the cylinder 30 in the combustion chamber 34, where no turbulence is generated. Therefore, the high-pressure air pushes the previously present fuel-rich mixture in the combustion chamber 34 toward the central axis of the cylinder 30. As a result, the previously present fuel-rich mixture in the combustion chamber 34 accumulates in the central region of the combustion chamber 34.

[0062] Thus, as Figure 4B As shown in the cross-sectional area A20, a mixed gas layer composed of fuel-rich gas is formed in the central region, as... Figure 4B As shown in the cross-sectional area A22, an air layer composed of high-pressure air is formed in the peripheral region. That is, the air supply unit 14 supplies air to the peripheral region of the combustion chamber 34, causing the fuel-rich mixture present in the combustion chamber 34 to accumulate in the central region of the combustion chamber 34, forming a layered structure consisting of a mixture layer in the central region and an air layer in the peripheral region. Regarding the air layer, since the previously present mixture is replaced by high-pressure air, almost no fuel is present.

[0063] When the gas mixture is ignited after such a layered structure has been formed, a flame is generated near the center of combustion chamber 34, such as... Figure 4C As shown in blank area A24, combustion of the gas mixture begins. Furthermore, the resulting flame spreads throughout the gas mixture, as... Figure 4D As shown in blank area A24, the combustion range of the gas mixture is expanded. Furthermore, as... Figure 4E As shown in blank area A24, the mixed gas gathered in the central area is completely burned.

[0064] Here, because an air layer is formed in the peripheral region of the combustion chamber 34, the flame does not propagate to this peripheral region, and combustion does not extend into the air layer. Therefore, in engine system 1, the flame propagation distance or the combustion distance of the gas mixture is substantially shorter than the radial thickness of the air layer. As a result, in engine system 1, all the gas mixture can be pre-combusted before the unburned mixture undergoes auto-ignition, thereby suppressing knocking sounds.

[0065] Furthermore, the fuel-rich mixture accumulates in the central region of the combustion chamber 34. Therefore, in engine system 1, the combustion rate of the mixture in the central region is faster than that of an ideally proportioned mixture. As a result, in engine system 1, all the mixture can be combusted earlier, thereby further suppressing knocking noise.

[0066] Furthermore, in engine system 1, because the air-fuel mixture is concentrated in the central region, it can burn more reliably. Therefore, in engine system 1, unburned losses of the air-fuel mixture can be reduced.

[0067] Furthermore, the air layer formed in the peripheral region of the combustion chamber 34 can also function as a heat insulation layer, suppressing the transfer of heat generated by the combustion of the air-fuel mixture to the inner circumferential surface 36 of the cylinder 30. Therefore, in the engine system 1, not only can knocking noise be suppressed, but heat loss can also be reduced.

[0068] Furthermore, in engine system 1, the air supply unit 14 is connected to the gap 40, through which high-pressure air is supplied. In other words, the air supply unit 14 does not supply high-pressure air radially from the cylinder head 24 directly toward the central axis of the combustion chamber 34. Instead, the air supply unit 14 supplies high-pressure air to the gap 40 in a downward direction, different from the radial direction, from the cylinder head 24 toward the cylinder block 20. Therefore, in engine system 1, the high-pressure air passes through the gap 40 before entering the combustion chamber 34, thereby changing the direction of high-pressure air flow and suppressing its velocity. As a result, in engine system 1, turbulence generated during the supply of high-pressure air can be appropriately suppressed, thus enabling the appropriate formation of a layered structure consisting of a gas-mixture layer and an air layer.

[0069] Furthermore, if turbulence is generated within the combustion chamber 34 when high-pressure air is supplied, the substantial flame propagation distance cannot be shortened, and knocking noise cannot be adequately suppressed. In contrast, in the engine system 1 of the embodiment, a layered structure consisting of a mixed gas layer and an air layer is formed so that turbulence is not generated, thus the substantial flame propagation distance can be appropriately shortened, thereby more appropriately suppressing the knocking noise of the engine 10.

[0070] The above is with reference to the appendix. Figure 1 While embodiments of the present invention have been described, it is self-evident that the present invention is not limited to these embodiments. Obviously, those skilled in the art will be able to conceive of various modifications or alterations within the scope of the claims, and understand that these modifications or alterations also fall within the technical scope of the present invention.

[0071] For example, in the above embodiment, high-pressure air is supplied from the air chamber 78 to the gap 40 through the connecting hole 80. However, the connecting hole 80 can directly connect the air chamber 78 and the combustion chamber 34 without passing through the gap 40. In this case, the flow rate of the high-pressure air is made such that it does not generate turbulence in the combustion chamber 34, and a layered structure consisting of a mixed gas layer and an air layer can be formed. For example, the opening of the connecting hole 80 facing the combustion chamber 34 can be formed as a micropore structure. In this case, the connection between the connecting hole 80 and the gap 40 can more appropriately form a layered structure consisting of a mixed gas layer and an air layer.

Claims

1. An engine system comprising: The combustion chamber is formed inside the cylinder; An air chamber is an annular passageway inside the cylinder head with the central axis of the cylinder as its axis. The cylinder head is disposed on the cylinder block that forms the cylinder in a manner that blocks the cylinder. The cylinder block and the cylinder head hold a gasket with an inner diameter larger than the diameter of the cylinder, thereby forming the gap in the shape of an annular plate between the cylinder block and the cylinder head. The gap is connected to the combustion chamber. Multiple connecting holes connect the air cavity and the gap portion, and are distributed along the circumferential direction of the air cavity; An air pressurization pump compresses air to generate high-pressure air at a first pressure, and supplies the high-pressure air to the combustion chamber via the air chamber, the connecting hole, and the gap. An air cam is connected to a camshaft that operates the intake valve and rotates in conjunction with the camshaft. as well as An air valve is installed on the piping from the air pressurization pump to the air chamber for supplying high-pressure air, and is linked to the rotation of the air cam to open or close the piping. The air pressurization pump supplies high-pressure air to the peripheral area around the inner circumference of the cylinder in the combustion chamber before ignition, causing the fuel-rich mixture present in the combustion chamber to accumulate in the central area of ​​the combustion chamber, forming a layered structure consisting of a mixed gas layer in the central area and an air layer in the peripheral area. The first pressure is a pressure higher than the second pressure inside the combustion chamber, and the pressure difference between the first pressure and the second pressure is within a predetermined range. The predetermined range is defined as the range within which the mixed gas in the combustion chamber does not generate turbulence even when the high-pressure air at the first pressure is supplied to the combustion chamber.

2. The engine system according to claim 1, wherein, High-pressure air is supplied to the combustion chamber after fuel injection has finished and during the compression stroke and before the mixture is ignited.

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