A natural gas engine combustion system

Abstract

The application discloses a natural gas engine combustion system and belongs to the technical field of engine combustion, and solves the problems of slow combustion speed and high engine thermal load of traditional spark ignition natural gas engines. The natural gas engine combustion system comprises a cylinder head, an intake valve and an exhaust valve, the bottom surface of the cylinder head is provided with a combustion chamber, the combustion chamber is a groove transversing the intake valve and the exhaust valve, a spark plug mounting hole in communication with the combustion chamber is further provided in the cylinder head, the axial center line of the spark plug mounting hole is located at the center of the combustion chamber, a sink groove is further provided at the top of the combustion chamber outside the spark plug mounting hole, an intake valve seat ring is arranged in the cylinder head corresponding to the bottom of the intake valve, an exhaust valve seat ring is arranged in the cylinder head corresponding to the bottom of the exhaust valve, and the axial center lines of the intake valve and the intake valve seat ring are both inclined to the direction of the air inlet of the air inlet duct relative to the bottom surface of the cylinder head. The natural gas engine combustion system can maintain a high level of swirl ratio and flow coefficient level, realize strong rolling flow and high-efficiency combustion.

Description

Technical Field

[0001] This invention relates to the field of engine combustion technology, and more specifically, to a natural gas engine combustion system. Background Technology

[0002] With the national strategic need for carbon peaking and neutralization, low-cost, low-carbon natural gas engine vehicles are increasingly accepted by customers. However, to further reduce carbon emissions and lower customer operating costs, high-efficiency, low-emission, and high-durability natural gas engines remain the industry's eternal pursuit.

[0003] Existing engines use, for example Figure 1 As shown, both intake valve 3 and exhaust valve 4 are arranged vertically, meaning they are both designed perpendicular to the bottom surface of cylinder head 1. Due to the guiding effect of intake valve seat 5 and intake valve seat mounting holes, vortex flow is easily achieved in the intake passage, but it is difficult to achieve a high tumble ratio without reducing the intake passage flow coefficient. Therefore, traditional spark-ignition natural gas engines suffer from problems such as slow combustion speed and high engine thermal load.

[0004] Therefore, there is an urgent need to develop and design a natural gas engine combustion system to solve the above-mentioned technical problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art. The purpose of the present invention is to provide a natural gas engine combustion system that can achieve strong tumble flow while maintaining a high level of vortex ratio and flow coefficient, thereby achieving efficient combustion.

[0006] To achieve the above objectives, the present invention provides a natural gas engine combustion system, including a cylinder head, an intake valve, and an exhaust valve. A combustion chamber is formed on the bottom surface of the cylinder head, and the combustion chamber is a groove spanning the intake and exhaust valves. A spark plug mounting hole communicating with the combustion chamber is also formed inside the cylinder head. The axis of the spark plug mounting hole is located at the center of the combustion chamber, and a recess is formed on the top of the combustion chamber outside the spark plug mounting hole. An intake valve seat is provided in the cylinder head corresponding to the bottom of the intake valve, and an exhaust valve seat is provided in the cylinder head corresponding to the bottom of the exhaust valve. The axes of the intake valve and the intake valve seat are inclined relative to the bottom surface of the cylinder head towards the intake manifold inlet. The axes of the exhaust valve and the exhaust valve seat are perpendicular to the bottom surface of the cylinder head, and the bottom surface of the exhaust valve and the exhaust valve seat are both located inside the cylinder head above the combustion chamber.

[0007] As a further improvement, the depth h of the combustion chamber is 4mm to 7mm.

[0008] Furthermore, the combustion chamber is a circular groove, and the center lines corresponding to the intake valve and exhaust valve are both located on the arc line of the circular groove.

[0009] Furthermore, the inner walls of the combustion chamber are all arc-shaped transition structures.

[0010] Furthermore, the angle α between the axis of the intake valve and the intake valve seat and the bottom surface of the cylinder head and the direction of the intake manifold is 3° to 10°.

[0011] Furthermore, the depth of the settling tank is 1mm to 3mm.

[0012] Furthermore, the sink is a circular sink, and the sink is located inside the area enclosed by the intake valve and the exhaust valve.

[0013] Furthermore, valve seat holes are provided in the cylinder head corresponding to the bottom of the intake valve and the cylinder head corresponding to the bottom of the exhaust valve, and the intake valve seat and the exhaust valve seat are press-fitted into the valve seat holes.

[0014] Beneficial effects Compared with the prior art, the advantages of this invention are as follows: The natural gas engine combustion system of the present invention forms a combustion chamber by cutting into the bottom of the cylinder head and combining it with the inclination of the intake valve and intake valve seat to achieve vortex. Compared with the traditional flat top cylinder head, it can achieve strong tumble flow while maintaining a high level of vortex ratio and flow coefficient, thereby improving the in-cylinder combustion speed, widening the EGR rate, reducing the engine exhaust temperature, and achieving efficient combustion. Meanwhile, this combustion system does not require a large structure on the original cylinder head, only valve seats, intake valves, and intake valve rocker arms. Compared with the traditional dome-shaped combustion cylinder head structure, it is a significant change and can realize a single camshaft solution on the intake side, which is low in cost. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the front view structure of the existing technology; Figure 2 This is a magnified front view of the corresponding position of the combustion chamber in this invention; Figure 3 This is a bottom view of the structure of the combustion chamber of the present invention at the corresponding position; Figure 4 This is a schematic diagram of the main structure corresponding to the intake valve position in this invention; Figure 5 This is a front view structural diagram of the corresponding position of the exhaust valve in this invention; Figure 6 This is a front view structural diagram of the corresponding position of the air intake in this invention.

[0016] Wherein: 1-Cylinder head, 2-Intake manifold, 3-Intake valve, 4-Exhaust valve, 5-Intake valve seat, 6-Spark plug mounting hole, 7-Exhaust valve seat, 8-Combustion chamber, 9-Groove. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments shown in the accompanying drawings.

[0018] See Figure 2-6 This invention discloses a natural gas engine combustion system, comprising a cylinder head 1, an intake valve 3, and an exhaust valve 4. A combustion chamber 8 is formed on the bottom surface of the cylinder head 1, which is a groove spanning the intake valve 3 and the exhaust valve 4. Specifically, the sidewall of the combustion chamber 8 passes through the corresponding positions of the intake valve 3 and the exhaust valve 4. A spark plug mounting hole 6, communicating with the combustion chamber 8, is also provided inside the cylinder head 1. The axis of the spark plug mounting hole 6 is located at the center of the combustion chamber 8, ensuring that the spark plug ignition point is within the combustion chamber. At the center of the combustion chamber 8, and on the top of the combustion chamber 8 outside the spark plug mounting hole 6, a groove 9 is provided, making it easier for the spark plug flame to spread around the combustion chamber 8. An intake valve seat 5 is provided in the cylinder head 1 corresponding to the bottom of the intake valve 3, and an exhaust valve seat 7 is provided in the cylinder head 1 corresponding to the bottom of the exhaust valve 4. The centerlines of the intake valve 3 and the intake valve seat 5 are both inclined relative to the bottom of the cylinder head 1 towards the intake manifold 2, causing the intake air to enter the combustion chamber 8 in an arc shape (e.g., ...). Figure 6 As shown by the dashed arrow, the intake airflow is smoother and more stable. The center lines of the exhaust valve 4 and the exhaust valve seat 7 are perpendicular to the bottom surface of the cylinder head 1. The bottom surface of the exhaust valve 4 and the exhaust valve seat 7 are located inside the cylinder head 1 above the combustion chamber 8, ensuring that the exhaust valve 4 disc sinks into the upper part of the combustion chamber 8, avoiding obstruction of the gas flowing into the intake manifold. This achieves a stronger tumble level than the traditional flat-top cylinder head, while maintaining the advantages of the traditional flat-top cylinder head, such as a strong swirl ratio and flow coefficient.

[0019] The natural gas engine combustion system of the present invention forms a combustion chamber 8 by cutting into the bottom of the cylinder head 1, and achieves vortex by combining the inlet valve 3 and the inlet valve seat 5 with inclination. Compared with the traditional flat top cylinder head, it can achieve strong tumble flow while maintaining a high level of vortex ratio and flow coefficient, thereby improving the in-cylinder combustion speed, widening the EGR rate, reducing the engine exhaust temperature, and achieving efficient combustion. Meanwhile, this combustion system does not require a large structure on the original cylinder head, only valve seats, intake valves, and intake valve rocker arms. Compared with the traditional dome-shaped combustion cylinder head structure, it is a significant change and can realize a single camshaft solution on the intake side, which is low in cost.

[0020] Preferably, the depth h of the combustion chamber 8 is 4mm to 7mm. Optimizing the depth of the combustion chamber 8 effectively ensures the structural strength of the cylinder head 1 while satisfying the requirement of increasing the tumble ratio. Furthermore, the combustion chamber 8 is a circular groove, and the centerlines of the intake valve 3 and exhaust valve 4 are located on the arc line of this circular groove, further ensuring strong tumble flow at high tumble ratio and flow coefficient levels. Even further, the inner sidewalls of the combustion chamber 8 have an arc-shaped transition structure, allowing the flame from combustion in the combustion chamber 8 to be better distributed into the cylinder bore of the cylinder block.

[0021] Preferably, the angle α between the axis of the intake valve 3 and the intake valve seat 5 and the bottom of the cylinder head 1 towards the intake port 2 is 3° to 10°, which can achieve a stronger tumble flow level while ensuring the stability of the intake valve 3 movement.

[0022] Preferably, the depth of the recess 9 is 1mm to 3mm to avoid excessive depth affecting spark plug ignition. Furthermore, the recess 9 is a circular groove, and the recess 9 is located inside the area enclosed by the intake valve 3 and the exhaust valve 4 to achieve ignition at the center of the combustion chamber 8.

[0023] Preferably, valve seat holes are provided in the cylinder head 1 corresponding to the bottom of the intake valve 3 and the cylinder head 1 corresponding to the bottom of the exhaust valve 4. The intake valve seat 5 and the exhaust valve seat 7 are press-fitted into the valve seat holes to achieve fixed installation of the intake valve seat 5 and the exhaust valve seat 7 and ensure the sealing performance of intake and exhaust.

[0024] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A natural gas engine combustion system, comprising a cylinder head (1), an intake valve (3), and an exhaust valve (4), characterized in that, The cylinder head (1) has a combustion chamber (8) on its bottom surface. The combustion chamber (8) is a groove spanning the intake valve (3) and the exhaust valve (4). The cylinder head (1) also has a spark plug mounting hole (6) communicating with the combustion chamber (8). The axis of the spark plug mounting hole (6) is located at the center of the combustion chamber (8). A groove (9) is also provided on the top of the combustion chamber (8) outside the spark plug mounting hole (6). The cylinder head (1) corresponding to the bottom of the intake valve (3) has a groove (9) in the center. An intake valve seat (5) is provided, and an exhaust valve seat (7) is provided in the cylinder head (1) corresponding to the bottom of the exhaust valve (4). The center lines of the intake valve (3) and the intake valve seat (5) are inclined relative to the bottom of the cylinder head (1) towards the intake port (2). The center lines of the exhaust valve (4) and the exhaust valve seat (7) are perpendicular to the bottom surface of the cylinder head (1). The bottom surface of the exhaust valve (4) and the exhaust valve seat (7) are located in the cylinder head (1) above the combustion chamber (8).

2. The natural gas engine combustion system according to claim 1, characterized in that, The depth h of the combustion chamber (8) is 4mm to 7mm.

3. A natural gas engine combustion system according to claim 2, characterized in that, The combustion chamber (8) is a circular groove, and the center lines of the intake valve (3) and exhaust valve (4) are located on the arc line of the circular groove.

4. A natural gas engine combustion system according to claim 3, characterized in that, The inner walls of the combustion chamber (8) are all arc-shaped transition structures.

5. A natural gas engine combustion system according to claim 1, characterized in that, The angle α between the axis of the intake valve (3) and the intake valve seat (5) and the bottom of the cylinder head (1) facing the intake port (2) is 3° to 10°.

6. A natural gas engine combustion system according to claim 1, characterized in that, The depth of the settling tank (9) is 1 mm to 3 mm.

7. A natural gas engine combustion system according to claim 6, characterized in that, The sink groove (9) is a circular groove, and the sink groove (9) is located inside the area enclosed by the intake valve (3) and the exhaust valve (4).

8. A natural gas engine combustion system according to any one of claims 1-7, characterized in that, Valve seat holes are provided in the cylinder head (1) corresponding to the bottom of the intake valve (3) and the cylinder head (1) corresponding to the bottom of the exhaust valve (4). The intake valve seat (5) and the exhaust valve seat (7) are press-fitted into the valve seat holes.

Images