Combustion system, combustion method, engine and vehicle

Abstract

This application relates to a combustion system, combustion method, engine, and vehicle. The combustion system includes a combustion cylinder and a return gas pipe. The combustion cylinder is connected to an intake pipe and an exhaust pipe. A first end of the return gas pipe is connected to the exhaust pipe, and a second end of the return gas pipe is connected to the combustion cylinder. The return gas pipe is configured to deliver at least a portion of the exhaust gas into the combustion cylinder, forming an exhaust gas layer surrounding the inner surface of the combustion cylinder. Air entering the combustion cylinder from the intake pipe is located within the area enclosed by the exhaust gas layer. Thus, the high-temperature exhaust gas layer can enclose the air, acting as an insulation layer during combustion, thereby reducing heat loss from the cylinder wall and allowing more heat to be used to drive the piston, improving engine efficiency.

Description

Technical Field

[0001] This application relates to the field of internal combustion engine technology, and in particular to a combustion system, combustion method, engine and vehicle. Background Technology

[0002] In related technologies, automobiles can introduce exhaust gases into the engine cylinders to improve engine thermal efficiency. However, the disordered distribution of exhaust gases and air within the engine cylinders still causes heat generated during combustion to dissipate through the cylinder walls, resulting in energy waste. Summary of the Invention

[0003] This application provides a combustion system, combustion method, engine, and vehicle that forms an exhaust gas layer on the inner surface of the combustion cylinder, so that the high-temperature exhaust gas layer can play a heat insulation role, preventing the heat generated by combustion from dissipating from the surface of the combustion cylinder and causing energy waste, thereby at least partially solving the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, a combustion system is provided, comprising:

[0005] The combustion cylinder is connected to the intake manifold and the exhaust manifold.

[0006] A return pipe, with its first end connected to the exhaust pipe and its second end connected to the combustion cylinder, is configured to deliver at least a portion of the exhaust gas into the combustion cylinder and form an exhaust gas layer surrounding the inner surface of the combustion cylinder.

[0007] The air entering the combustion cylinder from the intake pipe is located within the area enclosed by the exhaust gas layer.

[0008] Optionally, the return air pipe extends in a direction perpendicular to the axis of the combustion cylinder.

[0009] Optionally, the cross-section of the combustion cylinder is set to be circular, and the angle between the return gas pipe and the radius of the combustion cylinder through the gas outlet end of the return gas pipe is α, satisfying: 60°≤α≤120°.

[0010] Optionally, the included angle α is set to 90° so that the exhaust gas layer is vortex-shaped.

[0011] Optionally, at least two return gas pipes are provided, and the at least two return gas pipes are arranged at circumferential intervals along the combustion cylinder.

[0012] Optionally, the combustion cylinder has an air inlet and an air return port, the air inlet being connected to the air intake pipe and the air return port being connected to the air return pipe, wherein the air inlet is located above the air return port.

[0013] Optionally, the angle between the intake pipe and the axis of the combustion cylinder is β, satisfying: 0°≤β≤45°.

[0014] Optionally, the combustion system further includes:

[0015] A booster mechanism is installed in the intake pipe;

[0016] A drive mechanism is disposed in the exhaust pipe, the drive mechanism is connected to the booster mechanism, and the drive mechanism is configured to drive the booster mechanism to operate under the action of exhaust gas.

[0017] Optionally, the drive mechanism divides the exhaust pipe into a first exhaust section and a second exhaust section, the first exhaust section being connected to the combustion cylinder, wherein the return pipe is connected to the first exhaust section and / or the second exhaust section.

[0018] Optionally, the combustion system further includes:

[0019] An exhaust gas treatment mechanism is provided in the second exhaust section, and the exhaust gas treatment mechanism is configured to treat exhaust gas.

[0020] Optionally, the exhaust gas treatment mechanism divides the second exhaust section into a first section and a second section, and the return gas pipe is connected to the first section; and / or, the return gas pipe is connected to the second section; and / or, the return gas pipe is connected to the exhaust gas treatment mechanism.

[0021] Optionally, the combustion system further includes:

[0022] A bypass pipe, one end of which is connected to the first exhaust section and the other end of which is connected to the second exhaust section.

[0023] Optionally, the combustion system further includes:

[0024] The piston is movably mounted inside the combustion cylinder;

[0025] A fuel injector is disposed inside the combustion cylinder, with the injector's nozzle facing the piston.

[0026] Optionally, the injector is configured to spray a cone-shaped spray with a spray umbrella angle γ, satisfying: 15°≤γ≤150°.

[0027] Optionally, the piston moves to a point near the top dead center of the sprayer, where the radius of the spray is R1, and the cross-section of the combustion cylinder is circular with a radius of R2, satisfying: R1≤1 / 2R2.

[0028] Optionally, the piston has a diffusion chamber on the side facing the injector, the diffusion chamber being configured to allow the spray to diffuse.

[0029] Optionally, the depth of the diffusion chamber first increases and then decreases along the axis away from the combustion cylinder.

[0030] Optionally, the cross-section of the diffusion cavity is configured as ω-shaped.

[0031] Optionally, the piston moves to a point near the top dead center of the sprayer, where the radius of the spray is R1 and the radius of the diffusion chamber is R3, satisfying: R3≥R1.

[0032] According to a second aspect of this application, a combustion method is also provided, applied to the combustion system as described above, wherein, during one stroke of the piston, the injector performs at least two injections, the method comprising:

[0033] In response to the piston being at or near top dead center of its stroke, the injector makes a final injection.

[0034] According to a third aspect of this application, an engine is also provided, including the combustion system as described above.

[0035] According to a fourth aspect of this application, a vehicle is also provided, including the engine as described above.

[0036] The combustion system, combustion method, engine, and vehicle of this application embodiment supply air to the combustion cylinder through the intake manifold, thereby providing a combustion medium. The exhaust gases produced by combustion are discharged through the exhaust manifold. A return manifold can return a portion of the exhaust gases to the combustion cylinder, forming an exhaust gas layer surrounding the inner surface of the combustion cylinder. Because this exhaust gas layer can enclose the air, it acts as an insulation layer during combustion, reducing heat loss from the cylinder walls and allowing more heat to be used to drive the piston, thus improving engine efficiency.

[0037] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0040] Figure 1 This is a schematic diagram of the combustion system provided in an exemplary embodiment of this application;

[0041] Figure 2 This is a top view of the combustion cylinder provided in an exemplary embodiment of this application;

[0042] Figure 3 This is a partial cross-sectional view of the combustion cylinder provided in an exemplary embodiment of this application;

[0043] Figure 4 This is a schematic diagram of the structure of the injector provided in an exemplary embodiment of this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Combustion cylinder; 11. Piston; 111. Diffuser chamber; 12. Injector; 121. Spray; 13. Ignition device; 14. Shaft;

[0046] 2. Intake pipe; 21. Intercooler; 22. Throttle body;

[0047] 3. Exhaust pipe; 31. First exhaust section; 32. Second exhaust section; 321. First section; 322. Second section;

[0048] 4. Return air pipe; 41. Solenoid valve; 42. Air pump;

[0049] 5. Pressure boosting mechanism;

[0050] 6. Drive mechanism;

[0051] 7. Exhaust gas treatment system;

[0052] 8. Bypass pipe; 81. Bypass valve. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0054] Please see Figures 1 to 4This application provides a combustion system. The combustion system includes a combustion cylinder 1 and a return gas pipe 4. The combustion cylinder 1 is connected to an intake pipe 2 and an exhaust pipe 3. A first end of the return gas pipe 4 is connected to the exhaust pipe 3, and a second end of the return gas pipe 4 is connected to the combustion cylinder 1. The return gas pipe 4 is configured to deliver at least a portion of the exhaust gas into the combustion cylinder 1, forming an exhaust gas layer surrounding the inner surface of the combustion cylinder 1. Air entering the combustion cylinder 1 from the intake pipe 2 is located within the area enclosed by the exhaust gas layer.

[0055] In this embodiment, air is supplied to the combustion cylinder 1 through the intake pipe 2, thereby providing a combustion medium. The exhaust gas produced by combustion is discharged through the exhaust pipe 3. The return pipe 4 can return a portion of the exhaust gas to the combustion cylinder 1, forming an exhaust gas layer surrounding the inner surface of the combustion cylinder 1. Since the exhaust gas layer can enclose the air, it acts as a heat insulation layer during combustion, reducing heat loss from the cylinder wall of the combustion cylinder 1, allowing more heat to be used to drive the piston 11 and improve engine efficiency.

[0056] It is understandable that the air entering the combustion cylinder 1 from the intake manifold 2 is located in the area enclosed by the exhaust gas layer and comes into contact with the fuel spray 121 and burns. At this time, the exhaust gas layer can isolate the combustion environment from the cylinder wall of the combustion cylinder 1, thereby reducing the loss of energy generated by combustion from the cylinder wall of the combustion cylinder 1, and allowing more heat to be used to drive the piston 11 to do work, thus improving engine efficiency.

[0057] In this embodiment, exhaust gas is generated and forms an exhaust gas layer surrounding the inner surface of the combustion cylinder 1. External air entering the combustion cylinder 1 through the intake pipe 2 is located within the area enclosed by the exhaust gas layer. This creates a stratification of exhaust gas and fresh air: the inner layer of the combustion cylinder 1 is fresh air, and the outer layer is exhaust gas. Because exhaust gas has a high heat capacity, introducing it into the combustion cylinder 1 and forming an exhaust gas layer results in a smaller temperature rise in the exhaust gas layer due to the heat generated by combustion. This allows the exhaust gas layer to act as an insulation layer, ensuring that more of the heat generated by the combustion of air and fuel near the axis 14 of the combustion cylinder 1 is used to drive the piston 11, reducing heat dissipation from the cylinder wall and minimizing energy loss.

[0058] The stratified combustion described in this application refers to the stratification of exhaust gas and air, which is significantly different from stratified combustion in related technologies. Stratified combustion in related technologies refers to controlling the concentration of fuel spray 121 at different locations within the combustion cylinder 1. In this application, the stratified combustion results in a fresh air layer inside the combustion cylinder 1 and exhaust gas on the outer layer. The air mixes and burns with the fuel spray 121 near the axis 14 of the combustion cylinder 1, utilizing the exhaust gas for heat insulation.

[0059] In some embodiments, the return air pipe 4 extends in a direction perpendicular to the axis 14 of the combustion cylinder 1.

[0060] Understandably, the return pipe 4 extends along the axis 14 perpendicular to the combustion cylinder 1. When exhaust gas enters the combustion cylinder 1 from the return pipe 4, it can flow circumferentially along the inner surface of the combustion cylinder 1, forming an exhaust gas layer surrounding the inner surface of the combustion cylinder 1. This exhaust gas layer is roughly annular, thus enveloping the fresh air and fuel spray 121, achieving the effect of stratified combustion.

[0061] It should be noted that the return gas pipe 4 extends in a direction perpendicular to the axis 14 of the combustion cylinder 1, but the extension line of the return gas pipe 4 does not pass through the axis 14 of the combustion cylinder 1, so as to ensure that the exhaust gas blown out from the return gas pipe 4 can flow circumferentially along the inner surface of the combustion cylinder 1.

[0062] like Figure 2 As shown, in some embodiments, the cross-section of the combustion cylinder 1 is circular. The angle between the return gas pipe 4 and the radius of the outlet end of the combustion cylinder 1 through the return gas pipe 4 is α, which satisfies: 60°≤α≤120°.

[0063] It is understandable that the angle α between the return gas pipe 4 and the radius of the combustion cylinder 1 at the outlet of the return gas pipe 4 is set within the range of 60° to 120°. This allows the exhaust gas entering the combustion cylinder 1 from the return gas pipe 4 to flow in a vortex shape, thus creating a vortex-shaped exhaust gas layer. This ensures both the formation of a stratification effect and that the exhaust gas fully adheres to the inner surface of the combustion cylinder 1, ensuring the heat insulation effect of the exhaust gas layer. When the angle α between the return gas pipe 4 and the radius of the combustion cylinder 1 at the outlet of the return gas pipe 4 is less than 60°, the exhaust gas may blow into the middle area of ​​the combustion cylinder 1 after contacting the inner surface, affecting the stratification effect between the exhaust gas and air. When the angle α between the return gas pipe 4 and the radius of the combustion cylinder 1 at the outlet of the return gas pipe 4 is greater than 120°, the exhaust gas is more likely to blow directly into the middle area of ​​the combustion cylinder 1, also affecting the stratification effect between the exhaust gas and air.

[0064] For example, the angle α between the return pipe 4 and the radius of the combustion cylinder 1 through the outlet end of the return pipe 4 can be set to 60°, 90°, 120°, or any value between the two.

[0065] In some embodiments, the included angle α is set to 90° to make the exhaust gas layer vortex-like.

[0066] Understandably, with the included angle α set at 90°, the return gas pipe 4 and the combustion cylinder 1 are approximately tangentially positioned. When exhaust gas enters the combustion cylinder 1 from the return gas pipe 4, the exhaust gas can flow in a vortex-like manner along the inner surface of the combustion cylinder 1, thus creating a vortex-like exhaust gas layer. This vortex can envelop fresh air and fuel spray 121, achieving the effect of stratified combustion.

[0067] Based on the arrangement of the return pipe 4 in this application, the exhaust gas layer is vortex-shaped. When the exhaust gas and air are separated, the exhaust gas basically does not participate in combustion or only a small portion of the exhaust gas participates in combustion. As a result, the EGR rate (Exhaust Gas Recirculation Rate, the ratio of the amount of recirculated exhaust gas to the total amount of intake air into the cylinder) can be significantly improved, making it easy for the EGR rate to exceed 30%, and ensuring stable combustion and fast combustion speed.

[0068] In some embodiments, at least two return gas pipes 4 are provided, and the at least two return gas pipes 4 are arranged at circumferential intervals along the combustion cylinder 1.

[0069] It is understandable that by setting at least two return gas pipes 4 and arranging them at intervals along the circumference of the combustion cylinder 1, exhaust gas can be introduced at multiple locations along the circumference of the combustion cylinder 1 to better form a vortex-shaped exhaust gas layer. Specifically, the at least two return gas pipes 4 arranged circumferentially are located at the same height position in the combustion cylinder 1. That is, the at least two return gas pipes 4 are located at the same axial position in the combustion cylinder 1.

[0070] For example, the number of return air pipes 4 can be set to 2, 3, 4, 5, 6, or other numbers. Each return air pipe 4 is tangent to the combustion cylinder 1. The spacing between two adjacent return air pipes 4 may be the same or different.

[0071] In some embodiments, at least two return gas pipes 4 can be connected to a return gas main pipe, which can be equipped with a solenoid valve 41 and an air pump 42. The solenoid valve 41 and the air pump 42 can be used to control the introduction of exhaust gas and control the amount and pressure of exhaust gas introduced into the combustion cylinder 1 to ensure that sufficient exhaust gas is introduced into the combustion cylinder 1.

[0072] In some embodiments, when the combustion cylinder 1 is connected only to a tangentially arranged return gas pipe 4, a solenoid valve 41 and an air pump 42 may be installed on the return gas pipe 4. The solenoid valve 41 and the air pump 42 can be used to control the introduction of exhaust gas and control the amount and pressure of exhaust gas introduced into the combustion cylinder 1 to ensure that sufficient exhaust gas is introduced into the combustion cylinder 1.

[0073] In some embodiments, the combustion cylinder 1 has an air inlet and an air return port. The air inlet is connected to the air intake pipe 2. The air return port is connected to the air return pipe 4. The air inlet is located above the air return port.

[0074] Understandably, the air intake is connected to the intake pipe 2 to introduce fresh air into the combustion cylinder 1. The exhaust port is connected to the exhaust pipe 4 to introduce exhaust gas into the combustion cylinder 1. The air intake is positioned above the exhaust port to prevent air from passing through the exhaust gas layer, thus preventing air from disrupting the exhaust gas layer and affecting the stratification effect.

[0075] Of course, the combustion cylinder 1 also has an exhaust port, which is connected to the exhaust pipe 3, so as to discharge the exhaust gas generated by combustion from the combustion cylinder 1.

[0076] When there are multiple return air pipes 4, the number of return air ports is also set to multiple, with one return air pipe 4 corresponding to one return air port. Of course, there can also be multiple air inlets, thus connecting multiple air inlets 2, with one air inlet 2 corresponding to one air inlet.

[0077] like Figure 3 As shown, in some embodiments, the angle between the intake pipe 2 and the axis 14 of the combustion cylinder 1 is β, which satisfies: 0°≤β≤45°.

[0078] It is understandable that setting the angle β between the intake pipe 2 and the axis 14 of the combustion cylinder 1 in the range of 0° to 45° can prevent the air introduced into the combustion cylinder 1 from the intake pipe 2 from being blown into the exhaust gas layer due to an excessively large inlet angle, thus preventing the air from damaging the exhaust gas layer and affecting the stratification effect.

[0079] For example, the angle β between the intake pipe 2 and the axis 14 of the combustion cylinder 1 can be set to 0°, 15°, 30°, 45°, or any value between the two. Preferably, the angle β between the intake pipe 2 and the axis 14 of the combustion cylinder 1 is set to 0°, in which case the intake pipe 2 is parallel to the axis 14 of the combustion cylinder 1. That is, the intake pipe 2 is perpendicular to the top of the combustion cylinder 1.

[0080] In some embodiments, the intake manifold 2 may also be equipped with an intercooler 21 and a throttle valve 22. The intercooler 21 can cool the pressurized air, reduce the intake air temperature, and increase the intake air density. The throttle valve 22 can control the intake air volume and adjust the intake air volume based on combustion requirements.

[0081] In some embodiments, the combustion system further includes a booster mechanism 5 and a drive mechanism 6. The booster mechanism 5 is disposed in the intake manifold 2. The drive mechanism 6 is disposed in the exhaust manifold 3. The drive mechanism 6 is drively connected to the booster mechanism 5. The drive mechanism 6 is configured to drive the booster mechanism 5 to operate under the action of exhaust gas.

[0082] It is understandable that the exhaust gas discharged from combustion cylinder 1 is pressurized exhaust gas, which can act on drive mechanism 6 to drive booster mechanism 5. Booster mechanism 5 then compresses the intake air, thereby increasing the intake pressure and volume. Since the intake air is boosted using exhaust gas as a power source, there is no need to introduce an external power source, thus achieving full utilization of energy.

[0083] In some embodiments, the drive mechanism 6 is a turbine, and the booster mechanism 5 is a compressor, with the turbine and compressor coaxially connected. The pressurized exhaust gas discharged from the combustion cylinder 1 acts on the turbine, causing the turbine to drive the compressor to compress the intake air. Thus, based on the arrangement of the drive mechanism 6 and the booster mechanism 5, the intake air volume and intake pressure are increased.

[0084] In some embodiments, the drive mechanism 6 divides the exhaust pipe 3 into a first exhaust section 31 and a second exhaust section 32. The first exhaust section 31 is connected to the combustion cylinder 1. The return pipe 4 is connected to the first exhaust section 31 and / or the second exhaust section 32.

[0085] Understandably, after the exhaust gas performs work on the drive mechanism 6, the pressure of the exhaust gas will decrease. That is, the pressure of the exhaust gas in the first exhaust section 31 is greater than the pressure of the exhaust gas in the second exhaust section 32. When taking gas from the first exhaust section 31, it is easier to take gas, and the exhaust gas pressure is high, resulting in a large intake volume. When taking gas from the second exhaust section 32, it is relatively difficult to take gas, and the exhaust gas pressure is relatively low, resulting in a relatively small intake volume.

[0086] In some embodiments, the return pipe 4 is connected only to the first exhaust section 31. Alternatively, the return pipe 4 is connected only to the second exhaust section 32. Alternatively, the return pipe 4 is connected to both the first exhaust section 31 and the second exhaust section 32. In actual use, the return pipe 4 can be connected to the first exhaust section 31 and / or the second exhaust section 32 based on the air intake requirements.

[0087] In some embodiments, the combustion system further includes an exhaust gas treatment mechanism 7. The exhaust gas treatment mechanism 7 is disposed in the second exhaust section 32 and is configured to treat exhaust gases.

[0088] It is understandable that exhaust gas treatment devices treat the exhaust gas before it is released to meet emission standards.

[0089] The combustion system in this application embodiment can achieve high EGR rate combustion. High EGR rate combustion can not only improve engine thermal efficiency, but also enable the exhaust gas treatment mechanism 7 to adopt TWC (Three-Way Catalytic Converter), making the aftertreatment system low in cost and high in conversion efficiency.

[0090] In some embodiments, the exhaust gas treatment mechanism 7 divides the second exhaust section 32 into a first section 321 and a second section 322. The return gas pipe 4 is connected to the first section 321; and / or, the return gas pipe 4 is connected to the second section 322; and / or, the return gas pipe 4 is connected to the exhaust gas treatment mechanism 7.

[0091] Understandably, while treating the exhaust gas, the exhaust gas treatment mechanism 7 also reduces the pressure of the exhaust gas. Therefore, the pressure of the exhaust gas in the first section 321 is greater than the pressure of the exhaust gas inside the exhaust gas treatment mechanism 7, and the pressure of the exhaust gas inside the exhaust gas treatment mechanism 7 is greater than the pressure of the exhaust gas in the second section 322. The cleanliness of the exhaust gas in the first section 321 is less than that inside the exhaust gas treatment mechanism 7, and the cleanliness of the exhaust gas inside the exhaust gas treatment mechanism 7 is less than that inside the second section 322. Therefore, based on actual usage requirements, the return gas pipe 4 can be connected to one of the first section 321, the second section 322, or the exhaust gas treatment mechanism 7, thereby introducing the exhaust gas into the combustion cylinder 1.

[0092] In some embodiments, the combustion system further includes a bypass pipe 8. One end of the bypass pipe 8 is connected to the first exhaust section 31, and the other end is connected to the second exhaust section 32.

[0093] It is understandable that, based on the fact that the exhaust gas pressure will decrease after the exhaust gas does work on the drive mechanism 6, in order to ensure that the exhaust gas still has enough pressure to enter the exhaust gas treatment mechanism 7 for after-treatment, a part of the gas in the first exhaust section 31 is allowed to directly enter the second exhaust section 32 through the bypass pipe 8, so as to ensure that the exhaust gas in the second exhaust section 32 still has a certain pressure.

[0094] In some embodiments, a bypass valve 81 is provided on the bypass pipe 8. The bypass valve 81 is used to control the opening and closing of the bypass pipe 8, so as to control whether a portion of the gas in the first exhaust section 31 is directly introduced into the second exhaust section 32 through the bypass pipe 8.

[0095] In some embodiments, the combustion system further includes a piston 11 and an injector 12. The piston 11 is movably mounted within the combustion cylinder 1. The injector 12 is disposed within the combustion cylinder 1. The injection outlet of the injector 12 faces the piston 11.

[0096] Understandably, the injector 12 can spray fuel spray 121, which mixes with air and then burns. The energy generated by the combustion can drive the piston 11 to move, thereby driving other structural components.

[0097] like Figure 1 As shown, in order to achieve combustion of the fuel spray 121 sprayed by the injector 12, an igniter 13 is provided near the nozzle of the injector 12.

[0098] like Figure 4 As shown, in some embodiments, the injector 12 is configured to spray a cone-shaped spray 121. The spray umbrella angle of the spray 121 is γ, satisfying: 15°≤γ≤150°.

[0099] Understandably, the spray angle γ of the fuel injector 12 affects combustion efficiency and combustion effect. To ensure combustion efficiency and combustion effect, the spray angle can be made as large as possible to ensure that the fuel spray 121 has sufficient contact with the air, but it is necessary to ensure that the spray 121 does not enter the exhaust gas layer.

[0100] For example, the spray umbrella angle γ can be set to 15°, 60°, 90°, 150°, or any value between the two.

[0101] In some embodiments, the injection pressure of the injector 12 is greater than or equal to 200 bar. Pressures below 200 bar may result in poor fuel atomization. Based on the settings of injection pressure and injection dispersion angle in this embodiment, when the injector 12 performs multiple injections, better atomization can be achieved on the final injection, and excessive mixing of the spray 121 with air can be avoided.

[0102] In some embodiments, the piston 11 moves to a top dead center near the sprayer 121. At top dead center, the radius of the sprayer 121 is R1. The cross-section of the combustion cylinder 1 is circular. The radius of the combustion cylinder 1 is R2, satisfying: R1 ≤ 1 / 2R2.

[0103] It is understandable that top dead center is the position of maximum stroke when piston 11 moves upward. At top dead center, the radius R1 of spray 121 is less than or equal to half the radius R2 of combustion cylinder 1 to prevent fuel spray 121 from entering the exhaust gas layer and to prevent fuel waste.

[0104] For example, R1 = 1 / 2R2. Or, R1 = 1 / 3R2.

[0105] In some embodiments, the piston 11 has a diffuser cavity 111 on the side facing the injector 12. The diffuser cavity 111 is configured to allow the spray 121 to diffuse.

[0106] Understandably, the diffuser 111 provides diffusion space for the spray 121 while also limiting excessive diffusion, ensuring that the fuel spray 121 remains within the area corresponding to the diffuser 111. Based on the position of the diffuser 111, the fuel spray 121 can mix with air and burn near the axis 14 of the combustion cylinder 1, thus utilizing the external exhaust gas layer as a heat insulation layer to ensure the effect of stratified combustion.

[0107] It should be noted that the diffusion cavity 111 can be configured as annular or circular.

[0108] In some embodiments, the cavity depth of the diffuser cavity 111 first increases and then decreases along the axis 14 away from the combustion cylinder 1.

[0109] Understandably, the depth of the diffuser chamber 111 is first increased and then decreased along the axis 14 away from the combustion cylinder 1, so that the diffuser chamber 111 can accommodate the expansion of the fuel spray 121 and avoid excessive wall wetting. This ensures stratified combustion, allowing the fuel spray 121 to ignite and burn stably at a high EGR rate.

[0110] In some embodiments, the cross-section of the diffusion cavity 111 is configured as ω-shaped.

[0111] Understandably, the cross-section of the diffuser 111 is set to an ω-shape so that the diffuser 111 can accommodate the expansion of the fuel spray 121 and avoid excessive wall wetting. This ensures stratified combustion, allowing the fuel spray 121 to ignite and burn stably at high EGR rates.

[0112] In some embodiments, the piston 11 moves to a top dead center near the sprayer 121, at which point the radius of the spray 121 is R1 and the radius of the diffusion chamber 111 is R3, satisfying: R3≥R1.

[0113] It is understandable that top dead center is the position of maximum stroke when piston 11 moves upward. At top dead center, the radius R1 of spray 121 is less than or equal to the radius R3 of diffuser chamber 111, in order to prevent fuel spray 121 from being sprayed outside diffuser chamber 111 and affecting the diffusion effect, thus affecting the stratified combustion effect.

[0114] For example, R1 = R3. Or, R1 = 2 / 3R3.

[0115] According to a second aspect of this application, a combustion method is provided, which is applied to the combustion system as described above. This combustion method possesses all the beneficial effects of the aforementioned combustion system, which will not be elaborated further herein.

[0116] Specifically, during one stroke of the piston 11, the injector 12 performs at least two injections. Combustion methods include:

[0117] In response to the piston 11 being at or near the top dead center of its stroke, the injector 12 makes a final injection.

[0118] Understandably, by performing multiple injections during a single stroke of the piston 11, and by making the final injection when the piston 11 is at or near top dead center, the atomization effect of the final injection can be ensured. Furthermore, the diffuser chamber 111 of the piston 11 prevents excessive diffusion of the fuel spray 121 and facilitates its expansion, avoiding excessive wall wetting. This allows the fuel spray 121 to ignite and burn stably at high EGR rates.

[0119] For example, when piston 11 completes one stroke, injector 12 performs two injections, and in response to piston 11 being at top dead center, injector 12 performs a second injection.

[0120] For example, when piston 11 completes one stroke, injector 12 performs three injections, and in response to piston 11 being at top dead center, injector 12 performs a third injection.

[0121] For example, when the piston 11 completes one stroke, the injector 12 performs three injections, and in response to the piston 11 being in a position close to top dead center, the injector 12 performs a third injection.

[0122] It should be noted that the position near the top dead center can be 1 mm, 2 mm, 3 mm away from the top dead center, etc.

[0123] In some embodiments, the injection pressure of the injector 12 is greater than or equal to 200 bar. Pressures below 200 bar may result in poor fuel atomization. Based on the settings of injection pressure and injection dispersion angle in this embodiment, better atomization can be achieved during the final injection, and excessive mixing of the spray 121 with air can be avoided.

[0124] When the combustion method in this embodiment is applied to the aforementioned combustion system, the ω-shaped diffuser chamber 111 on the piston 11 can also cooperate with the last spray 121 to avoid excessive wall wetting and ensure the stratified combustion effect of the last spray 121, so that the fuel spray 121 can be stably ignited and burned at a high EGR rate.

[0125] According to a third aspect of this application, an engine is provided that includes the combustion system described above. This engine possesses all the beneficial effects of the aforementioned combustion system, which will not be elaborated further herein.

[0126] According to a fourth aspect of this application, a vehicle is provided that includes the engine described above, and the vehicle has all the beneficial effects of the engine described above, which will not be repeated here.

[0127] The vehicle can be a gasoline-powered car, a plug-in hybrid electric vehicle, etc., and this application does not specifically limit it.

[0128] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0129] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0130] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0131] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A combustion system characterized by, include: The combustion cylinder is connected to the intake manifold and the exhaust manifold. A return pipe, with its first end connected to the exhaust pipe and its second end connected to the combustion cylinder, is configured to deliver at least a portion of the exhaust gas into the combustion cylinder and form an exhaust gas layer surrounding the inner surface of the combustion cylinder. The air entering the combustion cylinder from the intake pipe is located within the area enclosed by the exhaust gas layer.

2. The combustion system of claim 1, wherein, The return gas pipe extends in a direction perpendicular to the axis of the combustion cylinder.

3. The combustion system of claim 2, wherein, The cross-section of the combustion cylinder is circular, and the angle between the return gas pipe and the radius of the combustion cylinder through the outlet end of the return gas pipe is α, satisfying: 60°≤α≤120°.

4. The combustion system of claim 3, wherein, The included angle α is set to 90° so that the exhaust gas layer is in a vortex shape.

5. The combustion system of claim 3, wherein, The return gas pipe is provided in at least two parts, and the at least two return gas pipes are arranged at circumferential intervals along the combustion cylinder.

6. The combustion system of claim 1, wherein The combustion cylinder has an air inlet and an air return port. The air inlet is connected to the air intake pipe, and the air return port is connected to the air return pipe. The air inlet is located above the air return port.

7. The combustion system of claim 6, wherein The angle between the intake pipe and the axis of the combustion cylinder is β, which satisfies: 0°≤β≤45°.

8. The combustion system of claim 1, wherein The combustion system also includes: A booster mechanism is installed in the intake pipe; A drive mechanism is disposed in the exhaust pipe, the drive mechanism is connected to the booster mechanism, and the drive mechanism is configured to drive the booster mechanism to operate under the action of exhaust gas.

9. The combustion system of claim 8, wherein, The drive mechanism divides the exhaust pipe into a first exhaust section and a second exhaust section. The first exhaust section is connected to the combustion cylinder. The return pipe is connected to the first exhaust section and / or the second exhaust section.

10. The combustion system of claim 9, wherein, The combustion system also includes: An exhaust gas treatment mechanism is provided in the second exhaust section, and the exhaust gas treatment mechanism is configured to treat exhaust gas.

11. The combustion system of claim 10, wherein, The exhaust gas treatment mechanism divides the second exhaust section into a first section and a second section, and the return gas pipe is connected to the first section; and / or, the return gas pipe is connected to the second section; and / or, the return gas pipe is connected to the exhaust gas treatment mechanism.

12. The combustion system of claim 9, wherein, The combustion system also includes: A bypass pipe, one end of which is connected to the first exhaust section and the other end of which is connected to the second exhaust section.

13. The combustion system of any one of claims 1 to 12, wherein, The combustion system also includes: The piston is movably mounted inside the combustion cylinder; A fuel injector is disposed inside the combustion cylinder, with the injector's nozzle facing the piston.

14. The combustion system of claim 13, wherein, The injector is configured to spray a cone-shaped spray with a spray umbrella angle γ, satisfying: 15°≤γ≤150°.

15. The combustion system of claim 14, wherein, The piston moves to a point near the top dead center of the sprayer, where the radius of the spray is R1. The cross-section of the combustion cylinder is circular, and the radius of the combustion cylinder is R2, satisfying: R1≤1 / 2R2.

16. The combustion system of claim 14, wherein The piston has a diffusion chamber on the side facing the injector, and the diffusion chamber is configured to allow the spray to diffuse.

17. The combustion system of claim 16, wherein Along the axis away from the combustion cylinder, the depth of the diffusion chamber first increases and then decreases.

18. The combustion system of claim 17, wherein, The cross-section of the diffusion cavity is set to ω-shaped.

19. The combustion system according to claim 16, characterized in that, The piston moves to a point near the top dead center of the sprayer, where the radius of the spray is R1 and the radius of the diffusion chamber is R3, satisfying that R3 ≥ R1.

20. A combustion method, characterized in that, Applied to a combustion system as described in any one of claims 1 to 19, wherein the injector performs at least two injections during one piston stroke, the method comprising: In response to the piston being at or near top dead center of its stroke, the injector makes a final injection.

21. An engine, characterized in that, The combustion system includes any one of claims 1 to 19.

22. A vehicle, characterized in that, Including the engine as described in claim 21.

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