Diesel engine and combustion chamber thereof

Abstract

The utility model relates to a diesel engine and a combustion chamber thereof. The combustion chamber of the diesel engine comprises a main body, a boss part and a pit part, the boss part is arranged on one side, far away from the top surface, of the main body, and is formed by protruding towards the direction close to the top surface; the pit part is connected with the boss part, the pit part is formed by sinking in the direction away from the top face, and a necking opening is formed in the end, close to the top face, of the pit part; in the depth direction, the range of the distance H1 from the top face to the deepest point of the pit part is 0.11 D-0. 15D, in the first direction, the range of the size D1 of the necking opening is 0.49 D-0. 53D, and D is the cylinder diameter of the diesel engine. Through the arrangement of the H1 and the D1, the volume of the combustion chamber is reduced, then a high compression ratio can be obtained, high compression pressure is provided through the high compression ratio, efficient combustion under the partial load working condition can be achieved, and the combustion efficiency is guaranteed; and meanwhile, the air utilization rate can be improved, fuel and air can be fully mixed and combusted, the fuel consumption of the engine is effectively reduced, and the requirements of high performance and low emission of the diesel engine are met.

Description

Technical Field

[0001] The present application relates to the technical field of diesel engines, and particularly to a diesel engine and its combustion chamber. Background Art

[0002] A diesel engine is an engine that obtains energy release by burning diesel. The advantages of a diesel engine are high torque and good economic performance. The working cycle of a diesel engine experiences four strokes: intake, compression, power, and exhaust. When a diesel engine works, the air enters the cylinder. When the air in the cylinder is compressed to the end, the temperature can reach 500 - 700 °C, and the pressure can reach 40 - 50 atmospheres. When the piston is close to the top dead center, the fuel injector of the fuel supply system injects fuel into the cylinder combustion chamber at an extremely high pressure in an extremely short time. The diesel forms fine oil particles, mixes with the high-pressure and high-temperature air, and the combustible mixture burns spontaneously, expands violently to generate an explosive force, and pushes the piston downward to do work. At this time, the temperature can reach 1900 - 2000 °C, and the pressure can reach 60 - 100 atmospheres, generating a large torque. Therefore, diesel engines can be widely used in large and heavy diesel equipment.

[0003] In response to the call for energy conservation and emission reduction, the performance requirements and emission requirements for diesel engines are becoming increasingly strict. In related technologies, a diesel engine cannot reduce both fuel consumption and nitrogen oxide emissions at the same time. This is because a diesel engine is a diffusion combustion, and the fuel injected into the cylinder is concentrated in a local area for combustion, resulting in local high temperature and oxygen deficiency, generating a large amount of soot, which affects fuel consumption, and nitrogen oxides will be generated in the oxygen-rich area.

[0004] Based on this, how to reduce fuel consumption and nitrogen oxide emissions has become one of the urgent problems to be solved in the current diesel engine field. Summary of the Invention

[0005] Based on this, it is necessary to provide a diesel engine and its combustion chamber for the problems of how to reduce fuel consumption and nitrogen oxide emissions.

[0006] The first aspect of the present application provides a combustion chamber of a diesel engine, which includes a main body, a convex platform part, and a concave pit part. The main body includes a top surface extending along a first direction; the convex platform part is arranged on the side of the main body away from the top surface and protrudes towards the top surface; the concave pit part is connected to the convex platform part and extends along the circumferential direction of the convex platform part. The concave pit part is recessed away from the top surface, and a necking is provided at the end of the concave pit part close to the top surface; wherein, in the depth direction, the distance from the top surface to the deepest point of the concave pit part is H1, and the range of H1 is 0.11D - 0.15D. In the first direction, the size of the necking is D1, and the range of D1 is 0.49D - 0.53D, where D is the cylinder diameter of the diesel engine, and the depth direction is perpendicular to the first direction.

[0007] In one embodiment, after the boss portion protrudes, a first included angle facing away from the top surface is formed, and the range of the first included angle is 120 - 130 degrees. Through the design of H1, D1, and the first included angle, the air flow in the combustion chamber is improved, enabling the effective mixing of fuel and air in the combustion chamber.

[0008] In one embodiment, in the depth direction, the distance from the top surface to the necking is H2, and the range of H2 is 0.04D - 0.08D. Through the settings of H1 and D1, the volume of the combustion chamber is reduced, and thus a higher compression ratio can be obtained. The high compression ratio provides a higher compression pressure, enabling efficient combustion under partial load conditions and ensuring the combustion efficiency.

[0009] In one embodiment, the ratio of H2 to H1 is K1, and the range of K1 is 0.45 - 0.55. The proportional relationship of H2 / H1 can ensure an appropriate design ratio to improve the early - stage fuel - air mixing efficiency, thereby increasing the early - stage heat release rate and ensuring combustion efficiency.

[0010] In one embodiment, the recessed portion further includes a flared opening. In the first direction, the size of the flared opening is D2, and the range of D2 is 0.5D - 0.55D.

[0011] In one embodiment, the ratio of D1 to D2 is K1, and the range of K1 is 0.97 - 0.99. The proportional relationship of D1 / D2 plays a key role in adjusting the mixing speed of fuel and air during the middle stage of combustion, ensuring a sufficient heat release rate during the middle - stage combustion. Through the settings of H1, D2, the first angle, and the D1 / D2 proportional relationship, the fuel - air hybrid power during the middle stage of combustion is ensured, thereby controlling the middle - stage heat release rate and ensuring a sufficient heat release rate during the middle - stage combustion. For partial load conditions, the increase in the middle - stage combustion heat release rate helps to improve the thermal efficiency. Under high - load conditions, the injection energy is high, and its mixing and combustion mainly depend on the injection energy and the mixing space provided by the combustion chamber during the injection duration. For partial load conditions, the injection duration is very short, and the injection energy is much lower than that under high - load conditions. Relying on air movement to provide higher mixing energy can more effectively increase the middle - stage combustion heat release, thereby improving the combustion efficiency under partial load conditions. The setting of the overall dimensions can make full use of oxygen everywhere, burn fuel orderly and efficiently. At the same time, because each part of the space is more fully utilized, the combustion temperature is generally reduced, which is beneficial to suppressing the generation of nitrogen oxides; ultimately, the working effects of efficient combustion, low emissions, and high reliability are achieved.

[0012] In one embodiment, the diesel engine combustion chamber further includes a lip portion, which is inclined relative to the top surface. The lip portion is circumferentially connected between the top surface and the pit portion along the circumference of the pit portion. A combustion chamber for fuel combustion is formed between the boss portion, the pit portion, the lip portion and the top surface. The beveled lip portion can reduce the risk of piston cracking and improve the reliability of the piston; the beveled lip portion can also enable the excess fuel to move along the bevel tangent to other oxygen-rich regions in the middle and late stages of combustion, improving the air utilization rate, thereby improving the combustion efficiency, and can also rapidly oxidize the soot emissions generated in the early stage, ultimately reducing the generation of soot.

[0013] In one embodiment, a second included angle is formed between the lip portion and the top surface, and the range of the second included angle is 28 - 40 degrees. By using the H2, H2 / H1 ratio relationship and the design of the second included angle, the fuel separation moment and ratio in the early stage of combustion are ensured, which is beneficial to promoting the early separation of fuel.

[0014] In one embodiment, the bore diameter of the diesel engine is 123 mm.

[0015] The second aspect of the present application provides a diesel engine, which includes a piston, a cylinder and a cylinder head. The piston is disposed inside the cylinder and can move relative to the cylinder. The piston includes the diesel engine combustion chamber in any of the above embodiments. The cylinder head is mounted on the cylinder, and the main body is disposed at the end of the piston close to the cylinder head.

[0016] In the above diesel engine combustion chamber, by setting the distance H1 from the top surface to the deepest point of the pit portion and the necking size D1, the volume of the combustion chamber is reduced, and thus a higher compression ratio can be obtained. The high compression ratio provides a higher compression pressure, which can achieve efficient combustion under partial load conditions and ensure the combustion efficiency; at the same time, this setting can improve the air utilization rate, enable the fuel and air to be fully mixed and burned, effectively reduce the fuel consumption of the engine, and meet the requirements of high performance and low emissions of the diesel engine; the setting of the distance H1 from the top surface to the deepest point of the pit portion can also reduce the oxygen content in the area where the pit portion is located, inhibit the generation of nitrogen oxides, and thus reduce the emissions of nitrogen oxides, meeting the requirements of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a diesel engine combustion chamber in an embodiment of the present application.

[0018] Figure 2 It is a schematic diagram of each structural parameter in the diesel engine combustion chamber in an embodiment of the present application.

[0019] Wherein, the reference numerals in the drawings are: boss portion 1, pit portion 2, necking 21, flaring 22, lip portion 3, top surface 4. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0021] An embodiment of the present application provides a diesel engine, which includes a piston, a cylinder, and a cylinder head; the piston is disposed inside the cylinder, and the piston moves up and down in the combustion chamber during the operation of the diesel engine to compress and then ignite the fuel-air mixture, and the generated energy is converted into mechanical energy to drive the crankshaft to rotate; the cylinder is a part of the inner wall of the combustion chamber, and the cylinder is used to maintain the lubrication and cooling inside the combustion chamber; the cylinder head is installed on the cylinder, the cylinder head seals the combustion chamber and can protect it from the erosion of the external environment, and at the same time the cylinder head also bears the force generated by combustion. The piston includes a diesel engine combustion chamber, and the diesel engine combustion chamber is disposed at the end of the piston, and the diesel engine combustion chamber is used for fuel combustion. The high temperature generated by the combustion of the diesel engine fuel causes the high-pressure gas to expand, and these gases in turn push the piston, thereby converting the chemical energy generated by the fuel combustion into mechanical energy, and finally driving the engine to generate electricity.

[0022] Refer to Figure 1 As shown, the diesel engine combustion chamber includes a main body, a boss portion 1, a pit portion 2, and a lip portion 3. The main body is disposed at the end of the piston close to the cylinder head. Preferably, the main body is integrally formed with the piston. The main body includes a top surface 4 extending along a first direction A. The boss portion 1 is disposed on the side of the main body away from the top surface 4, and the boss portion 1 protrudes toward the direction close to the top surface 4. Specifically, the boss portion 1 is located at the middle position of the main body. The pit portion 2 is disposed on the side of the main body away from the top surface 4. The pit portion 2 is connected to the boss portion 1 and extends along the circumferential direction of the boss portion 1. The pit portion 2 is recessed toward the direction away from the top surface 4. The lip portion 3 is connected between the top surface 4 and the pit portion 2 along the circumferential direction of the pit portion 2. Specifically, a circular arc surface is used for the transition between the lip portion 3 and the pit portion 2; a combustion chamber / combustion chamber for fuel combustion is formed among the boss portion 1, the pit portion 2, the lip portion 3, and the top surface 4.

[0023] In the embodiments disclosed in the present application, as Figure 2 , the first direction A is perpendicular to the depth direction B (appearing later). The first direction A is a horizontal direction, and the depth direction B is a vertical direction.

[0024] The pit portion 2 includes a necking 21 and a flaring 22. Specifically, the necking 21 is located at the end of the pit portion 2 close to the top surface 4, and the necking 21 contracts toward the direction close to the combustion chamber; the flaring 22 is the part where the pit portion 2 expands outward (away from the combustion chamber) to the maximum extent in the first direction A.

[0025] Reference Figure 2 As shown, in the depth direction B, the distance from the top surface 4 to the deepest point of the pit portion 2 is H1, and the range of H1 is 0.11D - 0.15D; the distance from the top surface 4 to the necking portion 21 is H2, and the range of H2 is 0.04D - 0.08D; the ratio of H2 to H1 is K1, and the range of K1 is 0.45 - 0.55. In the first direction A, the size of the necking portion 21 is D1, and the range of D1 is 0.49D - 0.53D; the size of the flaring portion 22 is D2, and the range of D2 is 0.5D - 0.55D; the ratio of D1 to D2 is K1, and the range of K1 is 0.97 - 0.99. After the convex platform portion 1 protrudes, a first included angle α1 is formed away from the top surface 4. From Figure 2 view, the first included angle α1 is formed between two inclined surfaces, and the range of the first included angle α1 is 120 - 130 degrees; a second included angle α2 is formed between the lip portion 3 and the top surface 4, and the range of the second included angle α2 is 28 - 40 degrees, where D is the cylinder bore of the diesel engine.

[0026] In the embodiment disclosed in the present application, the cylinder bore D of the diesel engine is 123 mm, that is, the range of the distance H1 from the top surface 4 to the deepest point of the pit portion 2 is 14.0 - 18.0 mm; the range of the distance H2 from the top surface 4 to the necking portion 21 is 5.0 - 10.0 mm; the range of the size D1 of the necking portion 21 is 60 - 66 mm; the range of the size D2 of the flaring portion 22 is 62 - 68 mm.

[0027] In the related art, a diesel engine cannot reduce both fuel consumption and nitrogen oxide emissions at the same time because the diesel engine has diffusion combustion, and the fuel injected into the cylinder is concentrated in local combustion, resulting in local high temperature and oxygen deficiency, generating a large amount of soot, which affects fuel consumption, and nitrogen oxides will be generated in the oxygen-rich area. In the present application, by setting the distance H1 from the top surface 4 to the deepest point of the pit portion 2 and the size D1 of the necking portion 21, the volume of the combustion chamber is reduced, and thus a higher compression ratio can be obtained. The high compression ratio provides a higher compression pressure, which can achieve efficient combustion under partial load conditions and ensure the combustion efficiency; at the same time, this setting can improve the air utilization rate, enable the fuel and air to be fully mixed and burned, effectively reduce the fuel consumption of the engine, and meet the requirements of high performance and low emissions of the diesel engine; the setting of the distance H1 from the top surface 4 to the deepest point of the pit portion 2 can also reduce the oxygen content in the area where the pit portion 2 is located, inhibit the generation of nitrogen oxides, and thus reduce the emissions of nitrogen oxides, meeting the requirements of energy conservation and emission reduction.

[0028] The engine compression ratio is defined as the sum of the volumes of the engine displacement, the cylinder head clearance, and the combustion chamber divided by the sum of the volumes of the cylinder head clearance and the combustion chamber. Extending this, the engine displacement is also the single-cylinder volume, and the cylinder head clearance is also the dead volume, which refers to all the space other than the combustion chamber volume after compression. The diesel engine combustion chamber of this application can achieve a compression ratio higher than 23.

[0029] This application also utilizes the distance H2 from the top surface 4 to the constriction 21, the proportional relationship between the distance H2 from the top surface 4 to the constriction 21 and the distance H1 from the top surface 4 to the deepest point of the pit 2, and the design of the second included angle α2 to ensure the fuel separation moment and ratio in the early stage of combustion, which is beneficial to promoting the early separation of fuel; the proportional relationship between the distance H2 from the top surface 4 to the constriction 21 and the distance H1 from the top surface 4 to the deepest point of the pit 2 can ensure an appropriate design ratio to improve the early-stage fuel-air mixing efficiency, thereby increasing the early heat release rate and ensuring combustion efficiency. Further, through the design of the distance H1 from the top surface 4 to the deepest point of the pit 2, the size D1 of the constriction 21, and the first included angle α1, the air flow in the combustion chamber is improved, enabling the effective mixing of fuel and air in the combustion chamber; the proportional relationship between the size D1 of the constriction 21 and the size D2 of the flare 22 plays a key role in adjusting the mixing speed of fuel and air in the middle stage of combustion. By setting the distance H1 from the top surface 4 to the deepest point of the pit 2, the size D2 of the flare 22, the first angle, and the proportional relationship between the size D1 of the constriction 21 and the size D2 of the flare 22, the fuel-air hybrid power in the middle stage of combustion is ensured, thereby controlling the middle-stage heat release rate and ensuring a sufficient heat release rate for the middle-stage combustion. For partial load conditions, the increase in the middle-stage combustion heat release rate helps improve the thermal efficiency. The injection energy is high under full load conditions, and its mixing and combustion more depend on the injection energy and the mixing space provided by the combustion chamber during the injection duration. For partial load conditions, the injection duration is very short, and the injection energy is much lower than that under full load conditions. Relying on air movement to provide higher mixing energy can more effectively increase the heat release in the middle stage of combustion, thereby improving the combustion efficiency under partial load conditions. The setting of the overall dimensions can make full use of oxygen everywhere, burn fuel in an orderly and efficient manner, and at the same time, because each part of the space is more fully utilized, the combustion temperature is generally reduced, which is beneficial to suppressing the generation of nitrogen oxides; ultimately, it achieves the working effects of efficient combustion, low emissions, and high reliability.

[0030] The diesel engine combustion chamber also includes a lip portion 3, and the lip portion 3 is inclined relative to the top surface 4, that is, the lip portion 3 is arranged in a beveled manner. The beveled lip portion 3 can reduce the risk of piston cracking and improve piston reliability; the beveled lip portion 3 can also make the excess fuel move along the beveled tangent to other oxygen-rich regions in the middle and late stages of combustion, improving the air utilization rate, thereby increasing the combustion efficiency. The increase in afterburning can also rapidly oxidize the soot emissions generated in the early stage, ultimately reducing the generation of soot.

[0031] The diesel engine is divided into four working processes: intake, compression, combustion, and exhaust. During the intake process of the diesel engine, the piston moves downward, the intake valve in the cylinder opens, and air enters through the intake passage. During the compression process of the diesel engine, the piston moves upward again to compress the air in the cylinder. In this process, the diesel engine reaches a very high compression ratio. The combustion process of the diesel engine is to inject high-pressure diesel into the cylinder through an injector. Due to the high pressure and high temperature, the diesel self-ignites in the cylinder, forming high-temperature gas to push the piston downward. The exhaust process of the diesel engine is that the piston moves upward again to discharge the burned exhaust gas through the exhaust valve, and then the injector injects diesel into the cylinder again to start the next working cycle. During the compression process of the diesel engine, in this application, by setting the distance H1 from the top surface 4 to the deepest point of the concave pit 2 and the size D1 of the necking 21, the volume of the combustion chamber is reduced, and thus a higher compression ratio can be obtained. The diesel engine combustion chamber of this application can achieve a compression ratio higher than 23. The high compression ratio provides a higher compression pressure, enabling efficient combustion under partial load conditions and ensuring the combustion efficiency. At the same time, this setting can improve the air utilization rate, enable the fuel and air to be fully mixed and burned, effectively reduce the fuel consumption of the engine, and meet the requirements of high performance and low emissions of the diesel engine.

[0032] The setting of the distance H1 from the top surface 4 of the present application to the deepest point of the pit portion 2 can also reduce the oxygen content in the area where the pit portion 2 is located, inhibit the generation of nitrogen oxides, and thus reduce the emission of nitrogen oxides, meeting the requirements of energy conservation and emission reduction. The design of the distance H2 from the top surface 4 of the present application to the necking 21, the ratio relationship between the distance H2 from the top surface 4 to the necking 21 and the distance H1 from the top surface 4 to the deepest point of the pit portion 2, and the second included angle α2 ensure the fuel separation moment and ratio in the early stage of combustion, which is beneficial to promoting the early separation of fuel. The ratio relationship between the distance H2 from the top surface 4 of the present application to the necking 21 and the distance H1 from the top surface 4 to the deepest point of the pit portion 2 can ensure an appropriate design ratio to improve the early-stage fuel-air mixing efficiency, thereby increasing the early-stage heat release rate and ensuring the high efficiency of combustion. The design of the distance H1 from the top surface 4 of the present application to the deepest point of the pit portion 2, the size D1 of the necking 21, and the first included angle α1 improve the air flow in the combustion chamber, enabling the fuel and air to be effectively mixed in the combustion chamber. The ratio relationship between the size D1 of the necking 21 and the size D2 of the flaring 22 of the present application plays a key role in adjusting the mixing speed of fuel and air in the middle stage of combustion. Through the setting of the distance H1 from the top surface 4 to the deepest point of the pit portion 2, the size D2 of the flaring 22, the first angle, and the ratio relationship between the size D1 of the necking 21 and the size D2 of the flaring 22, the fuel-air hybrid power in the middle stage of combustion is ensured, thereby controlling the heat release rate in the middle stage and ensuring a sufficient heat release rate for the middle-stage combustion. For part-load conditions, the increase in the heat release rate of the middle-stage combustion helps to improve the thermal efficiency. The injection energy at high-load conditions is high, and its mixing and combustion more depend on the injection energy and the mixing space provided by the combustion chamber during the injection duration. For part-load conditions, the injection duration is very short, and the injection energy is much lower than that at high-load conditions. Relying on air movement to provide higher mixing energy can more effectively increase the heat release in the middle stage of combustion, thereby improving the combustion efficiency at part-load conditions. The setting of the overall dimensions can make full use of oxygen everywhere, burn fuel in an orderly and efficient manner, and at the same time, because each part of the space is more fully utilized, the combustion temperature is generally reduced, which is beneficial to inhibiting the generation of nitrogen oxides; ultimately, it achieves the working effects of high-efficiency combustion, low emissions, and high reliability.

[0033] The present application adopts a direct injection combustion chamber structure. The diesel engine combustion chamber of the present application can improve the speed and uniformity of fuel-air mixing, improve the starting performance of the swirl combustion chamber, make the diesel engine easy to start, and has a soft sound, complete combustion, and environmentally friendly emissions.

[0034] In the description of the present application, it should be understood that if there appear such terms as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present application.

[0035] In addition, if there appear such terms as "first" and "second", these terms are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, if there appears the term "plurality", the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0036] In the present application, unless otherwise clearly specified and limited, if there appear such terms as "mounted", "connected", "coupled", "fixed", etc., these terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0037] In the present application, unless otherwise clearly specified and limited, if there appears a description such as a first feature being "on" or "under" a second feature, the meaning may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0038] It should be noted that if an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0039] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0040] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A diesel engine combustion chamber, characterized in that, Comprising: A main body including a top surface extending in a first direction; A boss portion provided on a side of the main body away from the top surface, the boss portion protruding in a direction close to the top surface; and A pit portion connected to the boss portion and extending along the circumferential direction of the boss portion, the pit portion being recessed in a direction away from the top surface, and a reduced opening being provided at an end of the pit portion close to the top surface; Wherein, in the depth direction, the distance from the top surface to the deepest point of the pit portion is H1, and the range of H1 is 0.11D - 0.15D. In the first direction, the size of the reduced opening is D1, and the range of D1 is 0.49D - 0.53D. D is the cylinder bore of the diesel engine, and the depth direction is perpendicular to the first direction.

2. The diesel engine combustion chamber according to claim 1, characterized in that, After the boss portion protrudes, a first included angle is formed away from the top surface, and the range of the first included angle is 120 - 130 degrees.

3. The diesel engine combustion chamber according to claim 1, characterized in that, In the depth direction, the distance from the top surface to the reduced opening is H2, and the range of H2 is 0.04D - 0.08D.

4. The diesel engine combustion chamber according to claim 3, characterized in that, The ratio of H2 to H1 is K1, and the range of K1 is 0.45 - 0.

55.

5. The diesel engine combustion chamber according to claim 1, characterized in that, The pit portion further includes a flared opening. In the first direction, the size of the flared opening is D2, and the range of D2 is 0.5D - 0.55D.

6. The diesel engine combustion chamber according to claim 5, characterized in that, The ratio of D1 to D2 is K1, and the range of K1 is 0.97 - 0.

99.

7. The diesel engine combustion chamber according to claim 1, characterized in that, The diesel engine combustion chamber further includes a lip portion, the lip portion is inclined relative to the top surface, the lip portion is connected along the circumferential direction of the pit portion between the top surface and the pit portion, and a combustion chamber for fuel combustion is formed among the boss portion, the pit portion, the lip portion and the top surface.

8. The diesel engine combustion chamber according to claim 7, characterized in that, A second included angle is formed between the lip portion and the top surface, and the range of the second included angle is 28 - 40 degrees.

9. The diesel engine combustion chamber according to any one of claims 1-8, characterized in that, The cylinder bore of the diesel engine is 123 mm.

10. A diesel engine, characterized in that, Including a piston, a cylinder and a cylinder head, the piston is arranged inside the cylinder and can move relative to the cylinder. The piston includes the diesel engine combustion chamber according to any one of claims 1 - 9. The cylinder head is installed on the cylinder, and the main body is arranged at an end of the piston close to the cylinder head.

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