Piston combustion chamber capable of reducing nitrogen oxide and engine oil gray emission
By setting up multiple convex and over -arc groups in the piston combustion room, changing the flow of fluid flow, forming multiple sections of vortex, solving the problem of low space utilization rate and large emissions in the existing combustion room, and achieved more efficient combustion and more more Low emissions.
Patent Information
- Application Number
- CN202421161055.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-24
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-05-24
AI Technical Summary
The space utilization rate of existing piston combustion chambers is low, resulting in large emissions of nitrogen oxides, particulate smoke and putty ash, which cannot effectively reduce emissions, affecting engine performance and customer usage costs.
By setting multiple convex and over -arc groups at the bottom and upper part of the combustion chamber, the fluid flow path, flow velocity and direction are changed to form multiple vortex flows and improve the degree of fuel and air.
Effectively reduce the emissions of nitrogen oxides, granular smoke and oil gray, improve the combustion efficiency, extend the oil exchange cycle, and reduce the cost of customer use.
Smart Images
Figure CN222415001U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of engines and relates to a piston combustion chamber which reduces the emission of nitrogen oxides and oil ash. Background Art
[0002] In the context of global energy conservation and emission reduction and increasingly fierce market competition, not only high requirements are placed on engine performance and fuel consumption, but also national emission regulations for engines are becoming more and more stringent; with the market's continuous pursuit of engine performance, under the condition of a certain cylinder volume, the engine compression ratio needs to be continuously improved to ensure its market competitiveness, but it will also bring emission-related challenges. As the compression ratio increases, the combustion volume becomes smaller when the piston is at the top dead center, and the pressure and temperature will also increase accordingly, which will weaken the gas flow in the combustion chamber, which is not conducive to oil and gas mixing, and then increase the carbon soot, nitrogen oxides, etc. produced by combustion, which brings about problems related to emission regulations. Therefore, the seesaw problem between engine performance and emissions needs to be solved urgently in current engine research and development. The current engine combustion chambers are generally divided into three categories: arc-shaped, U-shaped, and ω-shaped.
[0003] The structure of the existing piston combustion chamber is ω-shaped. The combustion chamber is surrounded by a cylinder, a cylinder head, a valve, an injector and a piston. The combustion chamber is located at the top of the piston and forms a central pit around the central axis. From the center of the top to the outer edge of the combustion chamber, there are the central top surface, α slope, arc pit, throat, β slope, transition fillet, straight slope, and injector central oil beam. The injector central oil beam and the central axis of the combustion chamber are 72.5°, and the central oil beam hits the lower side of the throat. The actual injector sprays out fan-shaped oil mist, which is divided at the throat. One part is guided to the bottom of the combustion chamber through the arc pit, and the other part is guided to the top of the combustion chamber through the β slope. Furthermore, the gas entering the combustion chamber through the intake system has a certain flow rate, which is guided by the combustion chamber wall, thereby forming a vortex with the fuel, and finally the oil and gas are fully mixed. However, the area outside the vortex formed in the combustion chamber has a relatively low utilization rate of air, which is not conducive to reducing its emission products: NOx (nitrogen oxides), PM (particlate mass particulate smoke), LOS (Lubeoil soot), and cannot achieve a lower LOS value, that is, a longer oil change cycle, which is not conducive to reducing customer usage costs. Utility Model Content
[0004] The utility model aims to provide a piston combustion chamber with reduced nitrogen oxide and oil ash emissions, solving the problems of low combustion chamber space utilization and large oil ash and nitrogen oxide emissions in the prior art.
[0005] The technical scheme adopted by the utility model is to provide a piston combustion chamber for reducing the emission of nitrogen oxides and oil ash. The combustion chamber is an ω-shaped combustion chamber arranged on the upper part of the piston. The central axis of the combustion chamber coincides with the central axis of the piston. The center of the bottom of the combustion chamber is a conical first boss. The bottom of the first boss is connected with a first arc. The bottom of the combustion chamber is provided with a second arc. The first arc and the second arc are smoothly transitioned. The other end of the second arc is smoothly transitioned to have a throat. The throat is smoothly connected to a third arc through a first slope. The free end of the third arc is smoothly connected to the bottom of a transition arc group. The upper part of the transition arc group is smoothly connected to a straight slope. The straight slope extends to connect with the top of the piston.
[0006] The utility model is also characterized in that:
[0007] The transition arc group includes a second slope, one end of the second slope is smoothly connected to the third arc, the other end of the second slope is smoothly connected to the second boss, the second boss is smoothly connected to the third slope, the third slope is smoothly connected to the fourth arc, and the free end of the fourth arc is smoothly connected to the straight slope.
[0008] There should be no less than two groups of excessive arcs.
[0009] The radius of the first arc is 2D / 135 to 2.6D / 135, where D represents the engine cylinder diameter.
[0010] The second boss is conical, and the radius of the second boss is 1D / 135 to 1.3D / 135.
[0011] The radius of the fourth arc is 1D / 135 to 1.3D / 135.
[0012] The radius of the fourth arc is not greater than the radius of the second boss.
[0013] The beneficial effects of the utility model are:
[0014] By changing the shape of the circular arc pit and the inclination angle of the β slope at the bottom of the combustion chamber, and adding an arc β boss at the intersection, the fluid flow path, fluid velocity and direction here are changed, thereby improving the turbulent kinetic energy of the fuel and air at the bottom of the combustion chamber and promoting their mixing degree; by setting a β boss between the β slope and the γ slope, the fluid flow path, fluid velocity and direction here are changed, and two sections of vortex are formed there, thereby improving the turbulent kinetic energy of the fuel and air in the upper part of the combustion chamber and promoting their mixing degree; it can effectively reduce Nox, PM, and LOS caused by emissions. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of the cross-sectional structure of a piston combustion chamber for reducing nitrogen oxide and oil ash emission of the utility model;
[0016] Figure 2The utility model is a structural schematic diagram of a transition arc group in a piston combustion chamber for reducing nitrogen oxide and oil ash emission.
[0017] In the figure, 1. piston, 2. combustion chamber, 3. first boss, 4. first arc, 5. second arc, 6. throat, 7. first slope, 8. third arc, 9. second slope, 10. transition arc group, 11. straight slope, 12. second boss, 13. third slope, 14. fourth arc. DETAILED DESCRIPTION
[0018] The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.
[0019] The piston combustion chamber of the utility model for reducing the emission of nitrogen oxides and oil ash is as follows: Figure 1 As shown, the combustion chamber is an ω-shaped combustion chamber 2 arranged on the upper part of the piston 1, the central axis of the combustion chamber 2 coincides with the central axis of the piston 1, the center of the bottom of the combustion chamber 2 is a conical first boss 3, the bottom of the first boss 3 is connected to a first arc 4, the bottom of the combustion chamber 2 is provided with a second arc 5, the first arc 4 and the second arc 5 are smoothly transitioned, the other end of the second arc 5 is smoothly transitioned to a throat 6, the throat 6 is smoothly connected to a third arc 8 through a first slope 7, the free end of the third arc 8 is smoothly connected to the bottom of a transition arc group 10, the upper part of the transition arc group 10 is smoothly connected to a straight slope 11, and the straight slope 11 extends to connect with the top of the piston 1.
[0020] like Figure 2 As shown, the transition arc group 10 includes a second slope 9, one end of the second slope 9 is smoothly connected to the third arc 8, the other end of the second slope 9 is smoothly connected to the second boss 12, the second boss 12 is smoothly connected to the third slope 13, the third slope 13 is smoothly connected to the fourth arc 14, and the free end of the fourth arc 14 is smoothly connected to the straight slope 11.
[0021] There should be no less than two groups of transition arc groups 10.
[0022] The radius of the first arc 4 is 2D / 135 to 2.6D / 135, where D represents the engine cylinder diameter.
[0023] The second boss 12 is conical, and the radius of the second boss 12 is 1D / 135 to 1.3D / 135.
[0024] The radius of the fourth arc 14 is 1D / 135 to 1.3D / 135.
[0025] The radius of the fourth arc 14 is not greater than the radius of the second boss 12 .
[0026] In order to further reduce the compression ratio, when the piston 1 is at the top dead center, the minimum clearance between the top of the piston 1 and the valve needs to ensure a certain safety margin, otherwise the top of the piston will interfere with the valve. Therefore, a valve avoidance pit is provided on the top of the piston 1. The valve avoidance pit will cut off part of the features of the boss, and it is required to retain at least half of the features of the boss. Therefore, the same beneficial effect as the above-mentioned combustion chamber is still achieved at the valve avoidance pit.
[0027] At least two transition arc groups 10 are arranged between the third circular arc 8 and the straight slope 11, and second bosses 12 are arranged in the transition arc groups 10. The arrangement of multiple second bosses 12 changes the fluid flow path, fluid velocity and direction here, thereby improving the turbulent kinetic energy of the fuel and air at the bottom of the combustion chamber and promoting the degree of mixing; multiple vortices will be formed at the multiple second bosses 12, thereby improving the turbulent kinetic energy of the fuel and air in the upper part of the combustion chamber 2 and promoting the degree of mixing; Nox, PM and LOS caused by emissions can be effectively reduced.
[0028] The characteristic of the straight slope 11 is maintained. The straight slope 11 is combined with the boss to form a vortex in the combustion chamber, further promoting the mixing of fuel and air.
[0029] By designing the shape of the second arc 5 at the bottom of the combustion chamber and the inclination angle of the bottom of the first boss 3, a first arc 4 is formed at the intersection thereof, so that the flow path, flow velocity and direction of the fluid passing therethrough are changed, thereby forming a stronger vortex, and promoting the mixing degree of the fuel and air at the lower part of the combustion chamber; by designing the inclination angles of the first slope 7 and the third slope 13, a second boss 12 is formed at the intersection thereof, so that the fluid path, flow velocity and direction of the fluid passing therethrough are changed, thereby forming a stronger vortex, promoting the mixing degree of the fuel and air at the upper part of the combustion chamber, and further promoting the mixing degree of the fuel and air. Therefore, the piston combustion chamber of the utility model can improve the combustion efficiency of the engine, and effectively improve the emission products of the engine, and reduce the emission of NOx, PM, and LOS.
[0030] Example 1
[0031] The utility model discloses a piston combustion chamber for reducing the emission of nitrogen oxides and oil ash, comprising an ω-shaped combustion chamber 2 arranged on the upper part of a piston 1, wherein the central axis of the combustion chamber 2 coincides with the central axis of the piston 1, a first conical boss 3 is arranged at the center of the bottom of the combustion chamber 2, a first arc 4 is connected to the bottom of the first boss 3, a second arc 5 is arranged at the bottom of the combustion chamber 2, the first arc 4 and the second arc 5 are smoothly transitioned, the other end of the second arc 5 is smoothly transitioned to a throat 6, the throat 6 is smoothly connected to a third arc 8 through a first slope 7, the free end of the third arc 8 is smoothly connected to the bottom of a transition arc group 10, the upper part of the transition arc group 10 is smoothly connected to a straight slope 11, and the straight slope 11 extends to connect with the top of the piston 1.
[0032] Example 2
[0033] The utility model discloses a piston combustion chamber for reducing the emission of nitrogen oxides and oil ash, comprising an ω-shaped combustion chamber 2 arranged on the upper part of a piston 1, wherein the central axis of the combustion chamber 2 coincides with the central axis of the piston 1, a first conical boss 3 is arranged at the center of the bottom of the combustion chamber 2, a first arc 4 is connected to the bottom of the first boss 3, a second arc 5 is arranged at the bottom of the combustion chamber 2, the first arc 4 and the second arc 5 are smoothly transitioned, the other end of the second arc 5 is smoothly transitioned to a throat 6, the throat 6 is smoothly connected to a third arc 8 through a first slope 7, the free end of the third arc 8 is smoothly connected to the bottom of a transition arc group 10, the upper part of the transition arc group 10 is smoothly connected to a straight slope 11, and the straight slope 11 extends to connect with the top of the piston 1.
[0034] The transition arc group 10 includes a second slope 9, one end of the second slope 9 is smoothly connected to the third arc 8, the other end of the second slope 9 is smoothly connected to the second boss 12, the second boss 12 is smoothly connected to the third slope 13, the third slope 13 is smoothly connected to the fourth arc 14, and the free end of the fourth arc 14 is smoothly connected to the straight slope 11.
[0035] Example 3
[0036] The utility model discloses a piston combustion chamber for reducing the emission of nitrogen oxides and oil ash, comprising an ω-shaped combustion chamber 2 arranged on the upper part of a piston 1, wherein the central axis of the combustion chamber 2 coincides with the central axis of the piston 1, a first conical boss 3 is arranged at the center of the bottom of the combustion chamber 2, a first arc 4 is connected to the bottom of the first boss 3, a second arc 5 is arranged at the bottom of the combustion chamber 2, the first arc 4 and the second arc 5 are smoothly transitioned, the other end of the second arc 5 is smoothly transitioned to a throat 6, the throat 6 is smoothly connected to a third arc 8 through a first slope 7, the free end of the third arc 8 is smoothly connected to the bottom of a transition arc group 10, the upper part of the transition arc group 10 is smoothly connected to a straight slope 11, and the straight slope 11 extends to connect with the top of the piston 1.
[0037] The transition arc group 10 includes a second slope 9, one end of the second slope 9 is smoothly connected to the third arc 8, the other end of the second slope 9 is smoothly connected to the second boss 12, the second boss 12 is smoothly connected to the third slope 13, the third slope 13 is smoothly connected to the fourth arc 14, and the free end of the fourth arc 14 is smoothly connected to the straight slope 11.
[0038] There are no less than two transition arc groups 10; the radius of the first arc 4 is 2D / 135~2.6D / 135, where D represents the engine cylinder diameter; the second boss 12 is conical, and the radius of the second boss 12 is 1D / 135~1.3D / 135; the radius of the fourth arc 14 is 1D / 135~1.3D / 135; the radius of the fourth arc 14 is not greater than the radius of the second boss 12.
[0039] The utility model is used in a heavy-duty diesel engine, and the basic parameters of the engine are listed in Table 1. The utility model is tested and verified. Under the same calibration and the same operating conditions, the performance and emission values of the engine of the existing combustion chamber and its piston and the piston combustion chamber of the utility model are horizontally compared. The specific calibration parameters and operating conditions are listed in Table 2, the specific engine performance parameters are listed in Table 3, and the specific emission parameters are listed in Table 4.
[0040] Table 1 Basic parameters of the engine
[0041] No. Item Unit Parameter 1 Cylinder diameter mm 135 2 Compression High mm 61 3 Connecting rod length mm 226.8 4 Crank radius mm 72.5 5 Compression ratio - 20.5 6 Eddy current ratio - 7 Number of cylinders indivual 6 8 Number of valves indivual 24 11 Piston pin eccentricity mm 0 12 Piston material - alloy steel 133 Crankshaft eccentricity mm 0
[0042] Table 2 Calibration parameters and operating conditions
[0043] No. Item Unit Parameter 1 Speed rpm 1800 2 Torque Nm 2150 3 power kW 405 4 Fuel injection amount mg / str 255.7 5 Advance Angle °C 8 6 Rail pressure bar 1150
[0044] Table 3 Engine performance parameters
[0045]
[0046]
[0047] Table 4 Emission parameters
[0048]
[0049] Combined with Tables 1 to 4, it can be seen that, under the premise of ensuring consistent engine performance and PM meeting regulatory requirements, the piston combustion chamber for reducing nitrogen oxide and oil ash emissions in this embodiment is compared with the existing combustion chamber, and NOx is effectively reduced by 14.47%, and LOS is effectively reduced by 87.5%, that is, by changing the shape of the circular arc pit and the inclination angle of the β slope at the bottom of the combustion chamber, adding an arc β boss at the junction thereof, thereby changing the fluid flow path, fluid velocity and direction here, thereby improving the turbulent kinetic energy of the fuel and air at the bottom of the combustion chamber, and promoting the degree of mixing; by setting the β boss between the β slope and the γ slope, thereby changing the fluid flow path, fluid velocity and direction here, forming two sections of vortex there, thereby improving the turbulent kinetic energy of the fuel and air in the upper part of the combustion chamber, and promoting the degree of mixing; NOx, PM, and LOS caused by emissions can be effectively reduced.
Claims
1. A piston combustion chamber for reducing nitrogen oxide and oil ash emissions, the combustion chamber being an ω-shaped combustion chamber (2) arranged on the upper part of a piston (1), characterized in that: The central axis of the combustion chamber (2) coincides with the central axis of the piston (1); the center of the bottom of the combustion chamber (2) is a conical first boss (3); the bottom of the first boss (3) is connected to a first arc (4); the bottom of the combustion chamber (2) is provided with a second arc (5); the first arc (4) and the second arc (5) are smoothly transitioned; the other end of the second arc (5) is smoothly transitioned to a throat (6); the throat (6) is smoothly connected to a third arc (8) through a first slope (7); the free end of the third arc (8) is smoothly connected to the bottom of a transition arc group (10); the upper part of the transition arc group (10) is smoothly connected to a straight slope (11); the straight slope (11) extends to connect with the top of the piston (1).
2. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 1, characterized in that: The transition arc group (10) comprises a second slope (9), one end of the second slope (9) is smoothly connected to the third circular arc (8), the other end of the second slope (9) is smoothly connected to a second boss (12), the second boss (12) is smoothly connected to the third slope (13), the third slope (13) is smoothly connected to a fourth circular arc (14), and the free end of the fourth circular arc (14) is smoothly connected to the straight slope (11).
3. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 2, characterized in that: The number of transition arc groups (10) is no less than two.
4. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 2, characterized in that: The radius of the first arc (4) is 2D / 135 to 2.6D / 135, where D represents the cylinder diameter of the engine.
5. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 2, characterized in that: The second boss (12) is conical, and the radius of the second boss (12) is 1D / 135 to 1.3D / 135.
6. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 2, characterized in that: The radius of the fourth arc (14) is 1D / 135 to 1.3D / 135.
7. The piston combustion chamber for reducing nitrogen oxide and oil ash emissions according to claim 6, characterized in that: The radius of the fourth circular arc (14) is no greater than the radius of the second boss (12).