A combustion chamber

Abstract

The present invention relates to the field of engine technology, and in particular to a combustion chamber, comprising: a cylinder, a piston, an injector and a combustion chamber body, wherein the piston reciprocates in the cylinder, the injector is arranged on the piston, the top surface of the piston is provided with a recessed portion, the recessed portion forms the combustion chamber body, the side wall of the combustion chamber body is provided with at least one annular step portion at intervals, wherein each of the annular step portions has a step surface, the two ends of the step surface are far away from each other and the connection with the side wall of the combustion chamber body is smoothly transitioned, a plurality of pits are spaced apart on the step surface, the opening size of the pits is greater than the depth of the pits, and the application adopts the above-mentioned design to effectively improve the space and air utilization rate in the cylinder, improve the uniformity of the combustible mixture, improve the fuel economy of the engine, and optimize the emission characteristics.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a combustion chamber. Background Art

[0002] In the relevant technology, internal combustion engines are required to continuously improve thermal efficiency and reduce pollutant emissions. For direct injection diesel engines, which adopt spray diffusion combustion, the mixing rate of fuel and air, the amount of combustible mixture and the uniformity have an important influence on the engine's power, fuel economy and emission characteristics. The shape of its combustion chamber directly determines the mixing quality of air and fuel. The combustion chambers of existing direct injection diesel engines are mostly "ω"-shaped. For diesel engines with medium and large cylinder diameters, the shape of the combustion chamber cannot provide enough space for the oil beam to mix with the air, reducing the uniformity of the combustible mixture, which will lead to excessively long combustion duration and serious afterburning, so that heat cannot be effectively utilized and fuel economy deteriorates. Summary of the invention

[0003] The embodiment of the present invention discloses a combustion chamber, which is used to enhance the circumferential diffusion of the oil beam, improve the spatial distribution of the oil-gas mixture, increase the utilization rate of the space and air in the cylinder, improve the uniformity of the combustible mixture, improve the fuel economy of the engine, and optimize the emission characteristics.

[0004] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] The present invention provides a combustion chamber, comprising: a cylinder, a piston, an injector and a combustion chamber body, wherein the piston reciprocates in the cylinder, the injector is arranged on the piston, a concave portion is arranged on the top surface of the piston, and the concave portion forms the combustion chamber body;

[0006] The side wall of the combustion chamber body is provided with at least one annular step portion at intervals, wherein each of the annular step portions has a step surface, and the two ends of the step surface that are far from each other are smoothly transitioned to the connection between the side wall of the combustion chamber body;

[0007] A plurality of pits are arranged on the step surface at intervals, the opening size of the pits is larger than the depth of the pits, and the number of the pits is the same as the number of the spray holes on the injector.

[0008] In the present application, at least one annular step portion is arranged at intervals on the side wall of the combustion chamber body, wherein each annular step portion will form a step area on the side wall of the combustion chamber body. When the basic profile of the combustion chamber body is a single step, the oil beam at this time will produce a vortex effect when it reaches the pit, thereby promoting the oil beam to diffuse to the surroundings, accelerating the mixing of the oil beam and fresh air, and improving air utilization. By the same token, when the basic profile of the combustion chamber body is a double step or a multi-step, when the oil beam reaches the pit of the first step, it will diffuse to the surroundings along the pit of the first step and mix with the nearby fresh air, thereby improving the air utilization in the circumferential direction of the cylinder, while the pit of the second step can improve the space utilization, so that the combustible mixture can diffuse faster under the action of a stronger vortex, and the uniformity is improved. The same is true for multiple steps. In summary, the present application adopts the above-mentioned design to effectively improve the space and air utilization in the cylinder, improve the uniformity of the combustible mixture, improve the fuel economy of the engine, and optimize the emission characteristics.

[0009] In some embodiments, the volume of the pit is Va, and the volume of the combustion chamber body is Vc, wherein a ratio γ of Va to Vc satisfies the following relationship: 0.02≤γ≤0.1.

[0010] In some embodiments, the rotation centerline of the pit cross section forms an angle α with the central axis of the combustion chamber body, and the angle α satisfies the following relationship: α≤45°.

[0011] In some embodiments, when there is one annular step portion, the annular step portion includes a first annular step, the pit includes a first pit opened on the first annular step, the cylinder diameter of the cylinder is D, the opening diameter D1 of the combustion chamber body satisfies: D1=0.8~0.85D, and the depth H1 of the combustion chamber body satisfies: H1=0.12~0.14D.

[0012] In some embodiments, the intersection of the first annular step and the longitudinal symmetric plane of the combustion chamber body includes a first endpoint and a second endpoint that are far away from each other, the first endpoint is located on the side of the second endpoint away from the bottom of the combustion chamber body, the opening diameter formed by the first endpoints is D1, and the opening diameter formed by the second endpoints is D B Satisfaction: D B =0.55~0.6D, and a depth H2 from the first endpoint to the second endpoint satisfies: H2=0.07~0.08D.

[0013] In some embodiments, the width d1 of the first pit opening satisfies: d1=0.6-0.7 (D1-D B ).

[0014] In some embodiments, when there are two annular step portions, the annular step portions include a first annular step and a second annular step, the connection between the second annular step and the first annular step is smoothly transitioned, the pit includes a first pit opened in the first annular step, and a second pit opened in the second annular step, the cylinder diameter of the cylinder is D, the opening diameter D1 of the combustion chamber body satisfies: D1=0.9~0.95D, and the depth H1 of the combustion chamber body satisfies: H1=0.12~0.14D.

[0015] In some embodiments, the intersection of the first annular step and the longitudinal symmetry plane of the combustion chamber body includes a first endpoint and a second endpoint that are far away from each other, the first endpoint is located on the side of the second endpoint away from the bottom of the combustion chamber body, the intersection of the second annular step and the longitudinal symmetry plane of the combustion chamber body includes a second endpoint and a third endpoint that are far away from each other, the opening diameter formed by the first endpoints is D1, the opening diameter formed by the second endpoints is D2 that satisfies: D2=0.6~0.65D, and the opening diameter formed by the third endpoints is D B Satisfaction: D B =0.5~0.55D, and a depth H2 from the first endpoint to the third endpoint satisfies: H2=0.07~0.08D.

[0016] In some embodiments, the width d1 of the first pit opening satisfies: d1=0.6-0.8 (D2-D B ), the width d2 of the second pit opening size satisfies: d2=0.6~0.7(D1-D2).

[0017] In some embodiments, along the longitudinal symmetry plane of the combustion chamber body, the cross-section of the pit is circular or elliptical. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the overall structure of a combustion chamber provided in an embodiment of the present invention having a layer of stepped portions;

[0019] Figure 2 A schematic diagram of a part of the structure of a combustion chamber provided in an embodiment of the present invention having a step portion;

[0020] Figure 3 for Figure 2 Schematic diagram of the structure of the aa section;

[0021] Figure 4 A schematic diagram of the overall structure of a combustion chamber provided in an embodiment of the present invention having two steps;

[0022] Figure 5A schematic diagram of a part of the structure of a combustion chamber provided in an embodiment of the present invention having two steps;

[0023] Figure 6 for Figure 5 Schematic diagram of the bb cross-section structure.

[0024] Among them: 1-piston, 11-combustion chamber body, 2-first annular step, 21-first pit, 22-first end, 23-second end, 3-second annular step, 31-second pit, 32-third end. DETAILED DESCRIPTION

[0025] The following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two.

[0026] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0027] The embodiment of the present invention discloses a combustion chamber, which is used to enhance the circumferential diffusion of the oil beam, improve the spatial distribution of the oil-gas mixture, increase the utilization rate of the space and air in the cylinder, improve the uniformity of the combustible mixture, improve the fuel economy of the engine, and optimize the emission characteristics.

[0028] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0029] Please refer to Figure 1-Figure 6 The present invention provides a combustion chamber, comprising: a cylinder, a piston 1, an injector and a combustion chamber body 11, wherein the piston 1 reciprocates in the cylinder, the injector is arranged on the piston 1, and a concave portion is arranged on the top surface of the piston 1, and the concave portion forms the combustion chamber body 11;

[0030] The side wall of the combustion chamber body 11 is provided with at least one annular step portion at intervals, wherein each annular step portion has a step surface, and the two ends of the step surface that are far from each other are smoothly transitioned to the connection with the side wall of the combustion chamber body 11;

[0031] A plurality of pits are arranged at intervals on the step surface, the opening size of the pits is larger than the depth of the pits, and the number of the pits is the same as the number of the spray holes on the injector.

[0032] In the present application, at least one annular step portion is arranged at intervals on the side wall of the combustion chamber body 11, and each annular step portion will form a step area on the side wall of the combustion chamber body 11. When the basic profile of the combustion chamber body 11 is a single step, the oil beam at this time will produce a vortex effect when it reaches the pit, thereby promoting the oil beam to diffuse to the surroundings, accelerating the mixing of the oil beam and fresh air, and improving air utilization. Similarly, when the basic profile of the combustion chamber body 11 is a double step or a multi-step, when the oil beam reaches the pit of the first step, it will diffuse to the surroundings along the pit of the first step and mix with the nearby fresh air, thereby improving the air utilization in the circumferential direction of the cylinder, while the pit of the second step can improve the space utilization, so that the combustible mixture can diffuse faster under the action of a stronger vortex, and the uniformity is improved. The same is true for multiple steps. In summary, the present application adopts the above-mentioned design to effectively improve the space and air utilization in the cylinder, improve the uniformity of the combustible mixture, improve the fuel economy of the engine, and optimize the emission characteristics.

[0033] Furthermore, the volume of the pit is Va, and the volume of the combustion chamber body 11 is Vc, wherein the ratio γ of Va to Vc satisfies the following relationship: 0.02≤γ≤0.1. The purpose of adopting the above design in the present application is to ensure that the combustion chamber body 11 has sufficient combustion space, while providing space for the oil beam to reach the pit to produce a vortex effect, thereby ensuring that the oil beam is mixed with the nearby fresh air and improving the air utilization rate in the circumferential direction of the cylinder.

[0034] Furthermore, the rotation centerline of the pit cross section forms an angle α with the central axis of the combustion chamber body 11, and the angle α satisfies the following relationship: α≤45°. The present application can reasonably set the basic profile of the combustion chamber body 11 (line aa in the figure) according to actual needs, and adjust the offset angle of the aa plane relative to the vertical plane where the center of the spray hole is located according to the swirl ratio, so that the oil beam can smoothly reach the pit for circumferential diffusion, thereby improving the air utilization rate. Specifically, when the swirl ratio is 0, the aa plane and the center of the spray hole are in the same plane; when the swirl ratio is greater than 0, the aa plane and the vertical plane where the center of the spray hole is located form a certain angle.

[0035] For further information, please refer to Figure 1-Figure 3In some embodiments, when there is one annular step portion, the annular step portion includes a first annular step 2, the pit includes a first pit 21 opened on the first annular step 2, the cylinder diameter is D, the opening diameter D1 of the combustion chamber body 11 satisfies: D1=0.8~0.85D, and the depth H1 of the combustion chamber body 11 satisfies: H1=0.12~0.14D. As can be seen from the figure, the present application sets a numerical relationship between the depth H1 of the combustion chamber body 11, the opening diameter D1 of the combustion chamber body 11 and the cylinder diameter D of the cylinder, so as to more accurately ensure that the combustion chamber body 11 can complete the combustion task.

[0036] For further information, please refer to Figure 2 , Figure 3 The intersection of the first annular step 2 and the longitudinal symmetric plane of the combustion chamber body 11 includes a first end 22 and a second end 23 that are far away from each other. The first end 22 is located on the side of the second end 23 that is away from the bottom of the combustion chamber body 11. The opening diameter formed by the first end 22 is D1, and the opening diameter formed by the second end 23 is D B Satisfaction: D B =0.55~0.6D, the depth H2 from the first end 22 point to the second end 23 point satisfies: H2=0.07~0.08D. From the above description, it can be seen that the first annular step 2 of the present application includes the first end 22 point and the second end 23 point which are far away from each other, and the opening diameter formed by the first end 22 points is the opening diameter D1 of the combustion chamber body 11, and the opening diameter D formed by the second end 23 points is set B A numerical relationship is set between the depth H2 from the first end point 22 to the second end point 23 and the cylinder diameter D of the cylinder, which better ensures that the combustion chamber body 11 can complete the combustion task.

[0037] For further information, please refer to Figure 3 The width d1 of the opening of the first pit 21 satisfies: d1=0.6~0.7 (D1-D B ). In the above structure, when the oil beam reaches position A in the figure, the oil beam will move and diffuse, part of the oil beam enters the bottom of the combustion chamber to mix with the air, and part of the oil beam enters the upper space. The oil beam reaching the pit will produce a vortex effect, which promotes the diffusion of the oil beam to the surroundings, accelerates the mixing of the oil beam and fresh air, and improves the air utilization rate.

[0038] For further information, please refer to Figure 4-Figure 6When there are two annular step portions, the annular step portions include a first annular step 2 and a second annular step 3, the connection between the second annular step 3 and the first annular step 2 is smoothly transitioned, the pit includes a first pit 21 opened in the first annular step 2, and a second pit 31 opened in the second annular step 3, the cylinder diameter is D, the opening diameter D1 of the combustion chamber body 11 satisfies: D1=0.9~0.95D, and the depth H1 of the combustion chamber body 11 satisfies: H1=0.12~0.14D. The present application adopts the above design to better ensure that the combustion chamber body 11 can complete the combustion task.

[0039] For further information, please refer to Figure 4 , Figure 5 The intersection of the first annular step 2 and the longitudinal symmetry plane of the combustion chamber body 11 includes a first end 22 and a second end 23 that are far away from each other. The first end 22 is located on the side of the second end 23 away from the bottom of the combustion chamber body 11. The intersection of the second annular step 3 and the longitudinal symmetry plane of the combustion chamber body 11 includes a second end 23 and a third end 32 that are far away from each other. The opening diameter formed by the first end 22 is D1, the opening diameter formed by the second end 23 satisfies: D2=0.6~0.65D, and the opening diameter formed by the third end 32 is D B Satisfaction: D B =0.5~0.55D, the depth H2 from the first end point 22 to the third end point 32 satisfies: H2=0.07~0.08D. From the above description, it can be seen that the first annular step 2 of the present application includes a first end point 22 and a second end point 23 that are far away from each other, and is connected to the second annular step 3 through the second end point 23, that is, when there are multiple annular step portions in the present application, the first annular step 2 and the second annular step 3 are smoothly connected. At the same time, the present application sets the data such as the first annular step 2 and the second annular step 3 to have an accurate numerical relationship with the cylinder diameter D of the cylinder, so as to better ensure that the combustion chamber body 11 can complete the combustion task.

[0040] For further information, please refer to Figure 6 The width d1 of the opening of the first pit 21 satisfies: d1=0.6~0.8 (D2-D B ), the width d2 of the opening size of the second pit 31 satisfies: d2=0.6~0.7 (D1-D2). When the basic profile of the combustion chamber body 11 is a double step, when the oil beam reaches the first pit 21, it diffuses along the pit to the surrounding area and mixes with the nearby fresh air to improve the air utilization rate in the circumferential direction of the cylinder. The second pit 31 improves the space utilization rate, so that the combustible mixture diffuses faster under the action of a stronger vortex, the uniformity is improved, and the combustion efficiency is further improved.

[0041] In some embodiments, along the longitudinal symmetry plane of the combustion chamber body 11, the cross-section of the pit is circular or elliptical. The present application adds a circle of pits at the step, the number of pit layers is consistent with the number of steps, the number of pits in each layer is consistent with the number of injector holes used, and the shape of the pit is a shallow pit shape with large radial and circumferential openings and a shallow axial depth. In addition, the present application does not make specific limitations on the cross-section of the pit, it only needs to satisfy that the cross-section of the pit is circular or elliptical. The present application adopts the above design, which can promote the circumferential diffusion of the oil beam, improve the diffusion speed and distribution of the combustible mixture in the circumferential direction, improve the overall uniformity, improve the space and air utilization, and optimize fuel economy.

[0042] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A combustion chamber, characterized in that: include: A cylinder, a piston, an injector and a combustion chamber body, wherein the piston reciprocates in the cylinder, the injector is arranged on the piston, a recess is arranged on the top surface of the piston, and the recess forms the combustion chamber body; The side wall of the combustion chamber body is provided with at least one annular step portion at intervals, wherein each of the annular step portions has a step surface, and the two ends of the step surface that are far from each other are smoothly transitioned to the connection between the side wall of the combustion chamber body; A plurality of pits are arranged on the step surface at intervals, the opening size of the pits is greater than the depth of the pits, and the number of the pits is the same as the number of the spray holes on the injector; There are multiple annular step portions, including a first annular step and a second annular step. The connection between the second annular step and the first annular step is smoothly transitioned. The pit includes a first pit opened in the first annular step and a second pit opened in the second annular step.

2. The combustion chamber according to claim 1, characterized in that The volume of the pit is Va, and the volume of the combustion chamber body is Vc, wherein the ratio γ of Va to Vc satisfies the following relationship: 0.02≤γ≤0.

1.

3. The combustion chamber according to claim 1, characterized in that The rotation center line of the pit cross section forms an angle α with the central axis of the combustion chamber body, and the angle α satisfies the following relationship: α≤45°.

4. The combustion chamber according to claim 1, characterized in that The cylinder diameter of the cylinder is D, the opening diameter D1 of the combustion chamber body satisfies: D1=0.9~0.95D, and the depth H1 of the combustion chamber body satisfies: H1=0.12~0.14D.

5. The combustion chamber according to claim 4, characterized in that The intersection of the first annular step and the longitudinal symmetry plane of the combustion chamber body includes a first endpoint and a second endpoint that are far away from each other, the first endpoint is located on the side of the second endpoint away from the bottom of the combustion chamber body, the intersection of the second annular step and the longitudinal symmetry plane of the combustion chamber body includes a second endpoint and a third endpoint that are far away from each other, the diameter of the opening formed by the first endpoints is D1, the diameter D2 of the opening formed by the second endpoints satisfies: D2=0.6~0.65D, and the diameter D B Satisfaction: D B =0.5~0.55D, and the depth H2 from the first endpoint to the third endpoint satisfies: H2=0.07~0.08D.

6. The combustion chamber according to claim 4, characterized in that The width d1 of the opening size of the first pit satisfies: d1=0.6~0.8 (D2-D B ), the width d2 of the opening size of the second pit satisfies: d2=0.6~0.7(D1-D2).

7. The combustion chamber according to claim 1, characterized in that Along the longitudinal symmetric plane of the combustion chamber body, the cross section of the pit is circular or elliptical.

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