Engine cylinder head, engine and control method therefor, and vehicle

Abstract

An engine cylinder head, an engine and a control method therefor, and a vehicle. The engine cylinder head comprises a cylinder head body (1), a main spark plug (2) and an auxiliary spark plug (3), wherein the cylinder head body (1) comprises a cylinder-head inner surface (11), the cylinder-head inner surface (11), a cylinder block (8) of an engine and a piston (9) in the cylinder block (8) being capable of forming a combustion chamber (7) by means of enclosure; the main spark plug (2) and the auxiliary spark plug (3) are arranged on the cylinder head body (1); and an electrode of the main spark plug (2) and an electrode of the auxiliary spark plug (3) both extend from the cylinder-head inner surface (11) and are located in the combustion chamber (7), the electrode of the main spark plug (2) is located at the center point of the cylinder-head inner surface (11) or is arranged close to the center point of the cylinder-head inner surface (11), and the electrode of the auxiliary spark plug (3) is arranged closer to an edge of the cylinder-head inner surface (11) than the main spark plug (2).

Description

An engine cylinder head, an engine and its control method, and a vehicle

[0001] This application claims priority to Chinese Patent Application No. 202410574578.1, filed on May 10, 2024, entitled "An Engine Cylinder Head, an Engine and a Control Method Thereof, and a Vehicle", and Chinese Patent Application No. 202410574886.4, filed on May 10, 2024, entitled "An Engine Cylinder Head, an Engine and a Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] The embodiments of the present invention relate to, but are not limited to, the field of vehicle component technology. Specifically, they relate to an engine cylinder head, an engine and its control method, and a vehicle. Background Technology

[0003] Lean combustion is widely used in engines. By controlling a higher air-fuel ratio (the higher the air-fuel ratio, the lower or leaner the mixture concentration in the engine combustion chamber), lean combustion can be achieved, simultaneously improving engine thermal efficiency and reducing pollutant emissions. However, if the mixture concentration is too low, the combustion speed will be slow, and this slow combustion speed may lead to incomplete combustion, thus increasing the risk of knocking. Furthermore, high-efficiency engines typically have very high compression ratios. When the combustion chamber space is compressed to its minimum by the piston moving to top dead center, the pressure inside the combustion chamber is at its maximum, and the edges of the combustion chamber are most prone to knocking, causing combustion deterioration and, in turn, limiting the improvement of thermal efficiency. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0005] This invention discloses an engine cylinder head, including a cylinder head body, a main spark plug, and an auxiliary spark plug. The cylinder head body includes an inner side surface, which can surround the engine block and the piston located in the block to form a combustion chamber. The main spark plug and the auxiliary spark plug are respectively disposed on the cylinder head body. The electrodes of the main spark plug and the auxiliary spark plug both extend out of the inner side surface of the cylinder head and are located in the combustion chamber. The electrode of the main spark plug is located at or near the center point of the inner side surface of the cylinder head, and the electrode of the auxiliary spark plug is located closer to the edge of the inner side surface of the cylinder head than the electrode of the main spark plug.

[0006] Optionally, the cylinder head body has a symmetrical structure, and the main spark plug is located on the symmetrical plane of the cylinder head body; the auxiliary spark plug is disposed on the symmetrical plane or distributed symmetrically with respect to the symmetrical plane.

[0007] Optionally, the engine cylinder head is a four-valve cylinder head, and one auxiliary spark plug is provided. The auxiliary spark plug is located between the two intake valves or the two exhaust valves of the four-valve cylinder head, and the auxiliary spark plug is located on the symmetrical plane of the cylinder head body; or, two auxiliary spark plugs are provided, and the two auxiliary spark plugs are respectively located between the two intake valves and the corresponding adjacent exhaust valves, and the two auxiliary spark plugs are symmetrical about the symmetrical plane of the cylinder head body.

[0008] Optionally, the cylinder head body is provided with valve seats that correspond one-to-one with the two intake valves and the two exhaust valves, and the minimum distance e between the auxiliary spark plug and the nearest valve seat is greater than or equal to 3mm.

[0009] Optionally, the engine cylinder head further includes an auxiliary fuel injector disposed on the cylinder head body. The inner side of the cylinder head is used to enclose and form a combustion chamber. The auxiliary fuel injector is used to spray a fuel jet toward the combustion chamber. The injection direction of the fuel jet is toward the electrode of the main spark plug, and the fuel jet does not contact the electrode of the main spark plug. The fuel jet passes below the electrode of the main spark plug, and the fuel in the fuel jet can diffuse toward the electrode of the main spark plug after evaporation.

[0010] Optionally, the oil jet is a conical oil jet with a cone angle β of 10° to 18°; and / or, the injection pressure of the auxiliary injector is 350 bar to 500 bar.

[0011] Optionally, the auxiliary injector injects two oil jets, the included angle α between the centerlines of the two oil jets is 20° to 45°, and the two oil jets are symmetrically arranged about the axis of the main spark plug.

[0012] Optionally, the auxiliary injector injects one of the fuel jets, and the centerline of the fuel jet intersects the axis of the main spark plug.

[0013] Optionally, the engine cylinder head further includes a main injector disposed on the cylinder head body, wherein the sum of the injection quantity of the main injector and the injection quantity of the auxiliary injector is the total injection quantity; when there are two fuel jets, the injection quantity of the auxiliary injector accounts for 5% to 15% of the total injection quantity, and the injection pulse width of the auxiliary injector is 10°CA to 20°CA; when there is one fuel jet, the injection quantity of the auxiliary injector accounts for 7% to 17% of the total injection quantity, and the injection pulse width of the auxiliary injector is 15°CA to 25°CA.

[0014] Optionally, the engine cylinder head is a four-valve cylinder head with a symmetrical structure. The main spark plug is located between the center line connecting the two exhaust valves of the four-valve cylinder head and the center point of the inner side of the cylinder head. The auxiliary fuel injector is located between the center line connecting the two intake valves of the four-valve cylinder head and the center point of the inner side of the cylinder head.

[0015] Optionally, the cylinder head body is further provided with an air intake passage. One end of the air intake passage that connects to the inner side of the cylinder head body is the air intake port. The plane where the axis of the main spark plug is located is designated as the first setting plane. The first setting plane is perpendicular to the plane formed by the axis of the main spark plug and the axis of the auxiliary injector. The air intake port and the auxiliary injector are both located on the same side of the first setting plane. The auxiliary injector is closer to the first setting plane than the air intake port. The air delivery direction of the air intake port intersects with the first setting plane. The center line of the fuel jet intersects with the first setting plane.

[0016] Optionally, the electrodes of the main spark plug include a center electrode and a side electrode; the minimum gap d between the surface of the fuel jet and the side electrode is 0.2 mm to 1 mm; or / and, the distance c between the center of one end of the auxiliary injector at the inner side of the cylinder head body and the center electrode is 10 mm to 16 mm.

[0017] The engine cylinder head of the present invention has the following beneficial effects: the inner side of the cylinder head body can be enclosed with the side wall of the cylinder block and the piston in the cylinder block to form a combustion chamber, wherein the electrodes of the main spark plug and the auxiliary spark plug both extend out of the inner side of the cylinder head, that is, the electrodes of the main spark plug and the auxiliary spark plug both extend into the combustion chamber. Thus, when a lean mixture is introduced into the combustion chamber and lean combustion is required, the electrodes of both the main spark plug and the auxiliary spark plug can be used to ignite the mixture in the combustion chamber, thereby increasing the combustion speed and reducing the knocking frequency during lean combustion. Specifically, after the electrode of the main spark plug ignites the nearby mixture, the flame can gradually spread to the periphery under the action of turbulence and flame diffusion. Since the main spark plug is located at or near the center point of the inner side of the cylinder head, the flame front can spread to the periphery in all directions after it is ignited, thereby increasing the combustion speed and shortening the combustion duration. At the same time, before the flame formed by the electrode of the main spark plug has spread to the edge of the combustion chamber, the electrode of the auxiliary spark plug, which is closer to the edge of the inner side of the cylinder head than the main spark plug, has already ignited the mixture at the edge of the combustion chamber, thereby reducing the frequency of knocking at the edge of the combustion chamber and ensuring high thermal efficiency during lean combustion.

[0018] This invention also discloses an engine, including the engine cylinder head as described above.

[0019] Since the technological improvements and effects of the engine are the same as those of the engine cylinder head, the engine will not be described in detail again.

[0020] This invention also discloses an engine control method, based on the aforementioned engine, the control method comprising:

[0021] When the air-fuel ratio of the air-fuel mixture in the engine's combustion chamber is lower than or equal to the first set value, the auxiliary spark plug and the main spark plug are controlled to ignite simultaneously.

[0022] And / or, when the air-fuel ratio of the mixture in the combustion chamber is greater than a first set value, the ignition timing of the auxiliary spark plug is controlled to be later than that of the main spark plug.

[0023] The engine control method of this invention has the following beneficial effects: When a lean mixture is required after filling the combustion chamber, the electrodes of the main spark plug and the auxiliary spark plug can be ignited together to ignite the mixture in the combustion chamber, thereby increasing the combustion speed and reducing the knock frequency during lean combustion. When the air-fuel ratio of the mixture in the combustion chamber is low, the mixture at this concentration can be ignited relatively stably by the spark plug. By controlling the simultaneous ignition of the auxiliary spark plug and the main spark plug, the combustion speed during lean combustion of the mixture in this concentration range can be increased and the knock frequency reduced. When the air-fuel ratio of the mixture in the combustion chamber is high, that is, when the mixture concentration is particularly lean, the main spark plug can be ignited first, and the auxiliary spark plug can be ignited after a certain period of time. Since the main spark plug has already been successfully ignited when the auxiliary spark plug ignites, the ignition of the auxiliary spark plug can be more stable and easier, which will also increase the overall combustion speed of the mixture and reduce the knock frequency.

[0024] This invention also discloses a vehicle including the engine described above.

[0025] Since the technological improvements and effects of the vehicle are the same as those of the engine, the vehicle will not be described in detail again.

[0026] After reading and understanding the detailed description, other aspects can be understood. Attached Figure Description

[0027] Figure 1 is a bottom view of the engine cylinder head structure according to an embodiment of the present invention;

[0028] Figure 2 is a bottom view of the engine cylinder head structure according to an embodiment of the present invention;

[0029] Figure 3 is a cross-sectional view of the engine cylinder head in Figure 2 at the plane of symmetry.

[0030] Figure 4 is a bottom view of the auxiliary injector spraying two oil jets according to an embodiment of the present invention.

[0031] Figure 5 is a partial cross-sectional view of the engine cylinder head at the valve in an embodiment of the present invention.

[0032] Figure 6 is a bottom view of the auxiliary injector spraying an oil jet according to an embodiment of the present invention;

[0033] Figure 7 is a schematic diagram showing the variation trend of the gas-fuel mixture λ value near the electrode of the spark plug in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached drawings: 1. Cylinder head body; 11. Inner side of cylinder head; 111. Concave part of cylinder head; 112. Inner flat part of cylinder head; 12. Intake manifold; 2. Main spark plug; 21. Side electrode; 22. Center electrode; 3. Secondary spark plug; 4. Intake valve; 5. Exhaust valve; 6. Secondary fuel injector; 61. Fuel jet; 7. Combustion chamber; 8. Cylinder block; 9. Piston; 10. Main fuel injector. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fitting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0037] In addition, it should be noted that in the description of the embodiments of the present invention, the terms and nouns in each embodiment, such as "upper," "lower," "front," and "rear," which indicate the location, are only used to simplify the description of the positional relationship based on the accompanying drawings. They do not mean that the components and devices referred to must be operated in accordance with the specific location and limited operation, method, and structure in the specification. Such directional terms do not constitute a limitation on the embodiments of the present invention.

[0038] Furthermore, in the attached figures, the X-axis represents the longitudinal direction, that is, the front-to-back direction, with the positive X-axis indicating front and the negative X-axis indicating back; the Y-axis represents the transverse direction, that is, the left-to-right direction, with the positive Y-axis indicating left and the negative Y-axis indicating right; and the Z-axis represents the vertical direction, that is, the up-down direction, with the positive Z-axis indicating up and the negative Z-axis indicating down. It should also be noted that the aforementioned X-axis, Y-axis, and Z-axis representations are merely for the convenience of describing the embodiments of the present invention and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0039] Referring to Figures 1 and 2, an engine cylinder head according to an embodiment of the present invention includes a cylinder head body 1, a main spark plug 2, and an auxiliary spark plug 3. The cylinder head body 1 includes an inner side surface 11, which can surround the engine block 8 and the piston 9 located in the block 8 to form a combustion chamber 7. The main spark plug 2 and the auxiliary spark plug 3 are respectively disposed on the cylinder head body 1. The electrodes of the main spark plug 2 and the auxiliary spark plug 3 both extend out of the inner side surface 11 and are located in the combustion chamber 7. The electrode of the main spark plug 2 is located at or near the center point O of the inner side surface 11, and the electrode of the auxiliary spark plug 3 is located closer to the edge of the inner side surface 11 than the main spark plug 2.

[0040] In this embodiment, the inner side 11 of the cylinder head body 1 can be enclosed with the side wall of the cylinder block 8 and the piston 9 inside the cylinder block 8 to form a combustion chamber 7. The electrodes of the main spark plug 2 and the auxiliary spark plug 3 both extend out of the inner side 11 of the cylinder head, that is, the electrodes of the main spark plug 2 and the auxiliary spark plug 3 both extend into the combustion chamber 7. Thus, when a lean mixture is filled into the combustion chamber 7 and lean combustion is required, the electrodes of the main spark plug 2 and the auxiliary spark plug 3 can be used together to ignite the mixture in the combustion chamber 7, thereby increasing the combustion speed and reducing the knock frequency during lean combustion. Specifically, after the electrode of the main spark plug 2 ignites the nearby mixture, the flame can gradually spread outwards under the influence of turbulence and flame diffusion. Since the main spark plug 2 is located at or near the center point O of the inner side surface 11 of the cylinder head, the flame front can spread outwards in all directions after ignition, increasing the combustion speed and shortening the combustion duration. Simultaneously, before the flame formed by the electrode of the main spark plug 2 has spread to the edge of the combustion chamber 7, the electrode of the auxiliary spark plug 3, which is closer to the edge of the inner side surface 11 of the cylinder head than the main spark plug 2, has already ignited the mixture at the edge of the combustion chamber 7, thereby reducing the frequency of knock at the edge of the combustion chamber 7 and ensuring high thermal efficiency during lean combustion.

[0041] Referring to Figure 3, the inner side 11 of the cylinder head body 1 can be the lower side of the cylinder head body 1. The lower side of the cylinder head body 1, together with the inner wall of the cylinder block 8 and the top surface of the piston 9, forms the combustion chamber 7.

[0042] It should be noted that, in order to improve combustion speed and shorten combustion duration, this embodiment places the main spark plug 2 at or near the center point O of the inner side surface 11 of the cylinder head. Thus, after the electrode of the main spark plug 2 ignites the nearby air-fuel mixture to form a flame, the flame can spread outwards from the electrode of the main spark plug 2 in all directions, thereby improving combustion speed and shortening combustion duration. However, since the piston 9 is usually moved to top dead center when the electrode of the main spark plug 2 is ignited, the space of the combustion chamber 7 is minimized, and the internal pressure is maximized. This may lead to knocking at the edge of the combustion chamber 7 under high pressure before the flame formed by the main spark plug 2 spreads to the edge. Therefore, in this embodiment, the auxiliary spark plug 3 is placed closer to the edge of the inner side surface 11 of the cylinder head than the main spark plug 2, so that the electrode of the auxiliary spark plug 3 ignites the air-fuel mixture at the edge before the flame formed by the main spark plug 2 spreads to the edge of the combustion chamber 7, thereby reducing the frequency of knocking.

[0043] It should be noted that the electrode of the main spark plug 2 is located at or near the center point O of the inner surface 11 of the cylinder head, including two options: the first option is that the electrode of the main spark plug 2 is located at the center point O of the inner surface 11 of the cylinder head; the second option is that the electrode of the main spark plug 2 is located near the center point O of the inner surface 11 of the cylinder head. In the second option, for example, the area within 8mm of the center point of the inner surface 11 of the cylinder head is considered to be near the center point O. The edge of the inner surface 11 of the cylinder head refers to the outermost edge of the inner surface 11 of the cylinder head.

[0044] Referring to Figures 1 and 2, the cylinder head body 1 has a symmetrical structure, and the main spark plug 2 is located on the symmetrical plane of the cylinder head body 1; the auxiliary spark plug 3 is disposed on the symmetrical plane or symmetrically distributed with respect to the symmetrical plane.

[0045] In this embodiment, the cylinder head body 1 has a symmetrical structure. Taking the four-valve cylinder head shown in Figures 1 and 2 as an example, its symmetry plane is parallel to the YZ plane and is located in the middle of the two intake valves 4 and the two exhaust valves 5. Based on this, when the main spark plug 2 is located at or near the center point O of the inner side surface 11 of the cylinder head, it is also located on the setting surface. The main spark plug 2 can be located at the center point O, slightly to the right of center point O, or slightly to the left of center point O on the inner side surface 11 of the cylinder head, to ensure that the main spark plug 2 is located on the setting surface. Specifically, "the main spark plug 2 is located on the setting surface" means that the axis of the main spark plug 2 is located on the setting surface. By placing the main spark plug 2 on the symmetry plane, the symmetry of the flame diffusion along the engine cylinder head is ensured, thereby reducing pressure fluctuations during flame propagation in the combustion chamber 7, which is beneficial for improving the overall NVH performance of the engine and reducing fuel consumption. In this embodiment, while adding an auxiliary spark plug 3, the auxiliary spark plug 3 is placed on the symmetrical plane or symmetrically distributed relative to the symmetrical plane. This can ensure the symmetry of the flame distribution of the auxiliary spark plug 3, thereby reducing the fluctuation of the flame propagation pressure in the combustion chamber 7, which is beneficial to improving the overall NVH performance of the engine and reducing fuel consumption.

[0046] Specifically, the engine cylinder head is a four-valve cylinder head, and one auxiliary spark plug 3 is provided. The auxiliary spark plug 3 is located between the two intake valves 4 or the two exhaust valves 5 of the four-valve cylinder head, and the auxiliary spark plug 3 is located on the symmetrical plane of the cylinder head body 1; or, two auxiliary spark plugs 3 are provided, and the two auxiliary spark plugs 3 are respectively provided between the two intake valves 4 and the corresponding adjacent exhaust valves 5, and the two auxiliary spark plugs 3 are symmetrical about the symmetrical plane of the cylinder head body 1.

[0047] In this embodiment, the engine cylinder head is a four-valve cylinder head, and there can be one auxiliary spark plug 3. In order to ensure the symmetry of the engine cylinder head, this auxiliary spark plug 3 is located on the symmetry plane of the cylinder head body 1. At this time, the auxiliary spark plug 3 is located between the two intake valves 4 or the two exhaust valves 5 of the four-valve cylinder head. Alternatively, there can be two auxiliary spark plugs 3. These two auxiliary spark plugs 3 are located on the front and rear sides of the symmetry plane of the cylinder head body 1, and these two auxiliary spark plugs 3 are symmetrical about the symmetry plane of the cylinder head body 1. At this time, the two auxiliary spark plugs 3 are respectively set between the two intake valves 4 and the corresponding adjacent exhaust valves 5.

[0048] It should be noted that, referring to Figures 1 to 3, in order to ensure a high compression ratio in the engine, the inner surface 11 of the cylinder head body 1 is not completely flat, but includes a concave portion 111 and a flat portion 112. The intake valve 4, exhaust valve 5, main spark plug 2, and auxiliary spark plug 3 are all located at the concave portion 111. Thus, the top dead center of the piston 9 inside the cylinder block 8 can be the position where the piston 9 abuts against the flat portion 112 of the cylinder head, thereby achieving a high compression ratio. The purpose of the flat portion 112 of the cylinder head is to ensure that the piston 9 does not interfere with the intake valve 4, exhaust valve 5, main spark plug 2, and auxiliary spark plug 3 when it moves to the top dead center.

[0049] Optionally, the cylinder head body 1 is provided with valve seats that correspond one-to-one with the two intake valves 4 and the two exhaust valves 5. The valve seats are used to support and seal the intake valves 4 or the exhaust valves 5. The minimum distance e between the auxiliary spark plug 3 and the nearest valve seat is greater than or equal to 3 mm.

[0050] In this embodiment, based on the four-valve cylinder head, the cylinder head body 1 is further provided with two intake passages and two exhaust passages. Valve seats are respectively provided at one end of the intake passages and exhaust passages located on the inner side surface 11 of the cylinder head. The valve seats support and seal the valves, ensuring that the passages do not leak when the valves are closed. Furthermore, as shown in Figure 1, the minimum distance e between the auxiliary spark plug 3 and the nearest valve seat is not less than 3mm. For example, when there is only one auxiliary spark plug 3, this single auxiliary spark plug 3 is not only close to the edge of the concave surface 111 of the cylinder head, but also located on the symmetrical plane between the two intake valves 4. The minimum distance e from the auxiliary spark plug 3 to the valve seat of the intake valve 4 is not less than 3mm, for example, e is 3mm, 4.5mm, or 5mm, to ensure that the wall thickness of the cylinder head body 1 between the mounting hole of the auxiliary spark plug 3 and the nearest intake passage is not less than 3mm, thereby ensuring a certain rigidity and preventing cracking. In addition, the minimum distance e between the auxiliary spark plug 3 and the nearest valve seat should not exceed 5mm to prevent the auxiliary spark plug 3 from having no space in the concave part 111 of the cylinder head and to prevent the electrode at the bottom of the auxiliary spark plug 3 from extending below the inner flat part 112 of the cylinder head.

[0051] Similarly, if there are two auxiliary spark plugs 3, as shown in Figure 2, these two auxiliary spark plugs 3 are located between the two intake valves 4 and the corresponding exhaust valves 5, respectively, and are both located near the edge of the concave surface 111 of the cylinder head. The two auxiliary spark plugs 3 are symmetrical about the cylinder head body 1. In this case, the minimum distance e between the auxiliary spark plug 3 and the valve seat of the left intake manifold is not less than 3mm, and the minimum distance e between the auxiliary spark plug 3 and the valve seat of the right intake manifold is not less than 3mm. The main spark plug 2 and auxiliary spark plug 3 can be small-diameter spark plugs of M12 or M10 (spark plug head diameter 12mm or 10mm). The diameter of the mounting hole required on the cylinder head body 1 is relatively small, making it easier to ensure that the distance e meets the requirements.

[0052] Optionally, both the main spark plug 2 and the auxiliary spark plug 3 are high-energy spark plugs, which generate higher energy and larger area of ​​electric arc after ignition, making it easier to ensure ignition stability.

[0053] Optionally, referring to Figures 1 to 4, the engine cylinder head further includes an auxiliary fuel injector 6 disposed on the cylinder head body 1. The inner side 11 of the cylinder head is used to enclose and form a combustion chamber 7. The auxiliary fuel injector 6 is used to spray a fuel jet 61 toward the combustion chamber 7. The injection direction of the fuel jet 61 is toward the electrode of the main spark plug 2, and the fuel jet 61 does not contact the electrode of the main spark plug 2. The fuel jet 61 passes under the electrode of the main spark plug 2, and the fuel in the fuel jet 61 can diffuse toward the electrode of the main spark plug 2 after evaporation.

[0054] In this embodiment, in order to ensure the ignition stability of the main spark plug 2 located at or near the center point O on the inner side surface 11 of the cylinder head, an auxiliary fuel injector 6 is also provided on the cylinder head body 1. Referring to Figures 4 to 6, after the intake manifold 12 and the main injector 10 at the intake manifold 12 supply a lean air-fuel mixture into the combustion chamber 7, and when the main spark plug 2 needs to be ignited, the auxiliary injector 6 can spray a fuel jet 61 into the combustion chamber 7. Since the fuel jet 61 is directed towards the bottom electrode of the main spark plug 2, and the fuel jet 61 does not contact the electrode of the main spark plug 2, that is, the direction of the fuel jet 61 sprayed by the auxiliary injector 6 is specifically towards the vicinity of the electrode of the main spark plug 2. In other words, the fuel jet 61 can pass near the bottom of the electrode of the main spark plug 2. Therefore, after the fuel in the fuel jet 61 sprayed by the auxiliary injector 6 evaporates, it can diffuse to the electrode of the adjacent main spark plug 2 to increase the local concentration of the air-fuel mixture at the electrode of the main spark plug 2. This allows the electrode of the main spark plug 2 to ignite the nearby richer air-fuel mixture more stably after ignition, that is, the ignition is more stable.

[0055] In this design, the fuel jet 61 is sprayed towards the electrode of the main spark plug 2, and the fuel jet 61 does not contact the electrode of the main spark plug 2. For example, the fuel jet 61 sprayed by the auxiliary injector 6 intersects the axis of the main spark plug 2 on the lower side of the electrode of the main spark plug 2. That is to say, the spray direction of the auxiliary injector 6 is towards the direct below of the main spark plug 2 (as shown in Figure 6), or towards a position near the direct below of the main spark plug 2, such as towards a position slightly forward and slightly backward of the direct below of the main spark plug 2 (as shown in Figure 4). This allows the fuel in the fuel jet 61 to diffuse more easily and more to the electrode of the main spark plug 2 after evaporation, so as to ensure the stability of the electrode ignition of the main spark plug 2.

[0056] Furthermore, since the fuel jet 61 injected by the auxiliary injector 6 is directed towards or near the main spark plug 2, rather than directly towards the electrodes of the main spark plug 2, the fuel jet 61 does not contact the electrodes of the main spark plug 2. This prevents fuel particles in the fuel jet 61 from adhering to the electrode surface of the main spark plug 2, thus avoiding the formation of an oil film on the electrode surface and preventing corrosion. In addition, the engine cylinder head of this embodiment does not require an additional pre-combustion chamber, an additional main spark plug 2, or any related structures connecting the pre-combustion chamber and the main combustion chamber, nor does it require corresponding optimization designs, resulting in lower costs.

[0057] Referring to Figure 2, optionally, the engine cylinder head is a four-valve cylinder head with a symmetrical structure. The main spark plug 2 is located between the line L2 connecting the centers of the two exhaust valves 5 of the four-valve cylinder head and the center point O of the inner side surface 11 of the cylinder head, that is, the main spark plug 2 is located between the connecting line L2 and the center point O; the auxiliary fuel injector 6 is located between the line L1 connecting the centers of the two intake valves 4 of the four-valve cylinder head and the center point O of the inner side surface 11 of the cylinder head, that is, the auxiliary fuel injector 6 is located between the connecting line L1 and the center point O.

[0058] Specifically, the engine cylinder head is a four-valve engine cylinder head, meaning it includes two intake valves 4 and two exhaust valves 5. The two intake valves 4 are respectively positioned to correspond one-to-one with the intake ports at the bottom of the two intake manifolds 12, and the two exhaust valves 5 are respectively positioned to correspond one-to-one with the exhaust ports at the bottom of the two exhaust manifolds. The intake valves 4 are used to open or close the corresponding intake ports, and the exhaust valves 5 are used to open or close the corresponding exhaust ports. The two intake valves 4 and the two exhaust valves 5 are symmetrical about a first setting line L3, and are also symmetrical about the first setting line L3. Furthermore, the two intake valves 4 and the two exhaust valves 5 are located on both sides of a second setting line L4. The first setting line L3 and the second setting line L4 intersect at the center point O of the inner side surface of the cylinder head body 1, and the first setting line L3 and the second setting line L4 are perpendicular.

[0059] In this embodiment, in order to ensure the rigidity of the cylinder head body 1, the main spark plug 2 and the auxiliary injector 6 should not be too close. Therefore, as shown in Figures 1, 2 and 4, the auxiliary injector 6 is designed between the center line L1 connecting the two intake valves 4 and the center point O, that is, the auxiliary injector 6 is located to the left of the center point O on the inner side surface 11 of the cylinder head; the main spark plug 2 is designed between the center line L2 connecting the two exhaust valves 5 and the center point O on the inner side surface 11 of the cylinder head, that is, the main spark plug 2 is designed to the right of the center point O on the inner side surface 11 of the cylinder head. In other words, the auxiliary injector 6 and the main spark plug 2 are located on the left and right sides of the center point O, respectively. In this way, the distance c between the auxiliary injector 6 and the main spark plug 2 is ensured to be neither too small nor too large, but between 10mm and 16mm, with c values ​​such as 10mm, 16mm, or 12mm. At the same time, it also ensures that the distance between the auxiliary injector 6 and the intake valve 4 is not too close, so that the wall thickness between the mounting hole where the auxiliary injector 6 is located and the intake manifold 12 is not too thin, thereby ensuring the rigidity of the cylinder head body 1 and preventing cracking. At the same time, it also ensures that the distance between the main spark plug 2 and the exhaust valve 5 is not too close, so that the wall thickness between the mounting hole where the main spark plug 2 is located and the exhaust manifold (not shown in the figure) is not too thin, thereby ensuring the rigidity of the cylinder head body 1. Furthermore, the auxiliary injector 6 is designed to be located slightly to the left of the center point O on the inner side of the cylinder head 11. In other words, compared to the distance from the main spark plug 2 to the exhaust port, the auxiliary injector 6 is farther away from the exhaust port. This ensures that the auxiliary injector 6 is far away from the exhaust passage corresponding to the exhaust valve 5, so as to prevent the high-temperature gas in the exhaust passage from causing high-temperature damage to the moving parts of the auxiliary injector 6, which is beneficial to improving the durability of the auxiliary injector 6.

[0060] Since the main spark plug 2 is designed to be slightly to the right of the center point O of the inner side of the cylinder head 11, as shown in Figure 1, optionally, at least one of the auxiliary spark plugs 3 is located between the two intake valves 4 near the edge of the inner side of the cylinder head 11. That is, at least one auxiliary spark plug 3 is located near the left edge of the inner side of the cylinder head 11. The auxiliary spark plug 3 at this position is the farthest from the main spark plug 2 located slightly to the right of the center point O of the inner side of the cylinder head 11, which is more conducive to reducing the knocking frequency.

[0061] As can be understood, referring to Figure 5, the engine cylinder head also includes a main injector 10 disposed on the cylinder head body 1, and the cylinder head body 1 is also provided with an intake passage 12. The end of the intake passage 12 that communicates with the inner side of the cylinder head body 1 is the air intake port. The main injector 10 can be disposed at the intake passage 12. The end of the intake passage 12 that communicates with the main combustion chamber, that is, the air intake port, can be closed or opened by the intake valve 4. Specifically, when lean combustion is required, air can first be introduced through the intake manifold 12 and fuel can be injected through the main injector 10, thereby forming a homogeneous lean mixture in the main combustion chamber (the air-fuel ratio λ value ranges from 1.4 to 3.0, for example, λ value is 2.8 as shown in Figure 7). Then, fuel jet 61 is injected through the auxiliary injector 6, as shown in Figure 7. As the auxiliary injector 6 starts injecting fuel, the mixture concentration near the electrode of the main spark plug 2 gradually increases (λ value near the electrode of the main spark plug 2 gradually decreases). When the λ value near the electrode of the main spark plug 2 becomes between 0.75 and 1.3, the electrode of the main spark plug 2 can be ignited to ignite the high-concentration mixture nearby, so as to ensure the ignition stability of the main spark plug 2. After the rich mixture near the electrode of the main spark plug 2 is burned, the surrounding lean mixture can be burned rapidly under the action of turbulence and flame diffusion.

[0062] It should be noted that the purpose of the auxiliary injector 6 in this embodiment is to spray fuel jet 61 near the electrode of the main spark plug 2 to increase the local air-fuel mixture concentration near the electrode; while the purpose of the main injector 10 is the same as in related technologies, which is to rapidly fill the main combustion chamber with fuel to form a lean air-fuel mixture with the air entering from the intake manifold 12. Therefore, the main injector 10 can have multiple (e.g., more than three) injection holes to simultaneously spray multiple fuel jets, thereby rapidly forming a certain amount of lean air-fuel mixture in the combustion chamber, while the auxiliary injector 6 in this embodiment can have only one or two injection holes to spray one or two fuel jets 61, thereby increasing the local air-fuel mixture concentration near the electrode of the main spark plug 2.

[0063] Optionally, as mentioned above, the engine cylinder head also includes a main injector 10 disposed on the cylinder head body 1, wherein the sum of the injection quantity of the main injector 10 and the injection quantity of the auxiliary injector 6 is the total injection quantity; when there are two fuel jets 61, the injection quantity of the auxiliary injector 6 accounts for 5% to 15% of the total injection quantity, and the injection pulse width of the auxiliary injector 6 is 10°CA to 20°CA; when there is only one fuel jet 61, the injection quantity of the auxiliary injector 6 accounts for 7% to 17% of the total injection quantity, and the injection pulse width of the auxiliary injector 6 is 15°CA to 25°CA.

[0064] In this embodiment, when there are two fuel jets 61, the fuel injection quantity of the auxiliary injector 6 accounts for 5% to 15% of the total fuel injection quantity (it can be 5%, 14%, or 15%). If the fuel injection quantity of the auxiliary injector 6 accounts for too high a proportion of the total fuel injection quantity (above 15%), the ratio of the total fuel injection quantity to air in the main combustion chamber will be high, that is, the overall air-fuel mixture concentration will be higher, which is not conducive to the high efficiency of lean combustion. If the fuel injection quantity of the auxiliary injector 6 accounts for too low a proportion of the total fuel injection quantity (below 5%), the air-fuel mixture concentration near the electrode may not be sufficient for ignition. The injection pulse width is 10°CA to 20°CA (it can be 10°CA, 12°CA, or 20°CA, etc.), as shown in Figure 7. For example, if the injection pulse width is 12°CA, when the crankshaft rotates to 690°, the auxiliary injector 6 starts injecting fuel to gradually reduce the λ value near the electrode. When the crankshaft rotates to 702°, the auxiliary injector 6 stops injecting fuel. At this time, the λ value near the electrode is reduced to its minimum. In this way, it is ensured that when the injection pulse width is 10°CA to 20°CA, the λ value of the air-fuel mixture near the electrode can be reduced to a certain range that can be ignited (the range where the λ value of the air-fuel mixture can be ignited can be 0.75 to 1.3 as shown in Figure 7).

[0065] When there is only one fuel jet 61, in order to further increase the area of ​​the rich mixture near the electrode, the fuel injection ratio and the fuel injection pulse width can be appropriately increased. For example, the fuel injection quantity of the auxiliary fuel injector 6 accounts for 7% to 17% of the total fuel injection quantity (it can be 7%, 16% or 17%, etc.), and the fuel injection pulse width is 15°CA to 25°CA (it can be 15°CA, 25°CA or 25°CA), so as to ensure that even a single fuel jet 61 can reduce the λ value of the mixture near the electrode to a certain range that can be ignited.

[0066] It should be noted that, as shown in Figures 1 and 3, the main spark plug 2 can be a type of main spark plug 2 from related technologies. Its electrodes include a center electrode 22 and a hook-shaped side electrode 21. There is a gap between the bottom end of the center electrode 22 and the side electrode 21. When the main spark plug 2 is energized, the current can break down the medium between the center electrode 22 and the side electrode 21 to generate a spark, thus creating a high-concentration air-fuel mixture near the spark plug. The axis of the main spark plug 2 is also the axis of the center electrode 22.

[0067] The fuel jet 61 ejected by the auxiliary injector 6 can overlap with the area near the electrodes. Specifically, the area near the midpoint between the center electrode 22 and the side electrode 21 is a spherical region with a radius of 5 mm, centered on the midpoint between the center electrode 22 and the side electrode 21. In this case, because the fuel jet 61 ejected by the auxiliary injector 6 can overlap with the area near the electrodes, even if the evaporated fuel within this area does not diffuse towards the center electrode 22, at least a portion of the evaporated fuel remains near the electrodes, increasing the air-fuel mixture concentration near the electrodes and making it ignitable by the electric spark.

[0068] It should be noted that, because the temperature and pressure inside the main combustion chamber are very high before the electrode is ignited, the fuel jet 61 sprayed from the bottom of the auxiliary injector 6 will quickly evaporate from liquid particles into gaseous state and then diffuse to the vicinity of the electrode of the main spark plug 2 to increase the air-fuel mixture concentration near the electrode (that is, to increase the air-fuel mixture λ value near the electrode).

[0069] Optionally, referring to Figures 3 and 5, as mentioned above, an intake passage 12 is also provided on the cylinder head body 1. One end of the intake passage 12 that communicates with the inner side of the cylinder head body 1 is the intake port. Let the plane where the axis of the main spark plug 2 is located be the first setting surface. The first setting surface is perpendicular to the plane formed by the axis of the main spark plug 2 and the axis of the auxiliary injector 6. The intake port and the auxiliary injector 6 are both located on the same side of the first setting surface. The auxiliary injector 6 is closer to the first setting surface than the intake port. The air delivery direction of the intake port intersects with the first setting surface. The center line of the fuel jet 61 intersects with the first setting surface.

[0070] The fact that the auxiliary injector 6 is closer to the first setting surface than the air intake means that the distance from the bottom center of the auxiliary injector 6 to the first setting surface is less than the distance from the center of the air intake to the first setting surface.

[0071] In this embodiment, as shown in Figure 3, the first setting surface is a plane containing the axis of the main spark plug 2, and is perpendicular to the plane formed by the axis of the main spark plug 2 and the axis of the auxiliary injector 6, that is, it is perpendicular to the YZ plane; the air intake and the auxiliary injector 6 are both located on the same side of the first setting surface, that is, the air intake and the auxiliary injector 6 are both located on the left side of the first setting surface, and the auxiliary injector 6 is closer to the first setting surface than the air intake, that is, the auxiliary injector 6 is located on the right side of the center of the air intake. Thus, when the air intake of the intake manifold 12 delivers air into the main combustion chamber, since the air delivery direction of the intake manifold intersects with the first set surface (i.e., the air delivery direction of the intake manifold is towards the first set surface on its right), the airflow delivered by the intake manifold moves downward to the right and, after hitting the right side wall of the main combustion chamber, it turns left and then right again after hitting the left side wall of the main combustion chamber, thus forming a clockwise tumble. During the subsequent injection of fuel jet 61 by the auxiliary injector 6 located to the right of the center of the intake manifold, this clockwise tumble can blow the gaseous fuel in the fuel jet 61 to the electrode of the main spark plug 2, thereby increasing the amount of richer air-fuel mixture near the electrode of the main spark plug 2 and further ensuring the stability of the ignition of the main spark plug 2. Secondly, this tumble can also lengthen and enlarge the electric arc generated after the electrode of the main spark plug 2 is ignited, making the ignition more stable. The air intake direction can be set at an angle to the fuel jet 61 injection direction. That is, the angle between the air intake direction and the horizontal plane can be smaller than the angle between the fuel jet 61 injection direction and the horizontal plane. This allows the clockwise movement of the tumble flow to pass through the subsequently injected fuel jet 61, so that more gaseous fuel in the fuel jet 61 is blown toward the electrode of the main spark plug 2.

[0072] Optionally, referring to Figures 3 and 4, the minimum gap d between the surface of the oil jet 61 and the side electrode 21 is 0.2 mm to 1 mm; or / and, the distance c between the center of one end of the auxiliary injector 6 at the inner side of the cylinder head body 1 and the end of the center electrode 22 is 10 mm to 16 mm.

[0073] In this embodiment, the fuel jet 61 can specifically be a conical fuel jet. This shape helps to evenly spray fuel into the cylinder, and the fuel jet 61 can be better designed to minimize the gap between itself and the side electrode 21. Furthermore, since the electrode profile of the main spark plug 2 is primarily formed by the side electrode 21, and the outer profile of the fuel jet 61 is its surface, the minimum gap between the surface of the fuel jet 61 and the side electrode 21 is the minimum gap between the electrode and the fuel jet 61. As shown in Figure 3, the minimum gap d between the surface of the fuel jet 61 and the side electrode 21 is 0.2 mm to 1 mm, for example, d is 0.2 mm, 1 mm, or 0.5 mm.

[0074] In this embodiment, if the d value is small (less than 0.2 mm), the main spark plug 2 and the auxiliary injector 6 need to be assembled with high precision on the cylinder head body 1. Furthermore, due to assembly errors, interference may occur between the fuel jet 61 and the side electrode 21. If interference occurs, the oil particles in the fuel jet 61 may directly form an oil film on the side electrode 21, causing corrosion to the side electrode 21. If the d value is large (greater than 1 mm), the fuel vaporized into gaseous state in the fuel jet 61 will not easily move to the vicinity of the electrode to increase the concentration near the electrode.

[0075] It is understandable that the surface of the oil jet 61 refers to its surface before evaporation. After the fuel particles in the oil jet 61 evaporate into a gaseous state, they will diffuse out of this surface.

[0076] In this embodiment, the distance c between the center of one end of the auxiliary injector 6 on the inner side of the cylinder head body 1 and the center electrode 22 is 10mm to 16mm. That is, the distance between the center of the bottom end of the auxiliary injector 6 and the bottom end of the center electrode 22 is 10mm to 16mm, for example, 10mm, 12mm or 16mm. If the distance is too small (less than 10mm), the wall thickness between the mounting hole of the auxiliary injector 6 and the mounting hole of the main spark plug 2 will be small, which will affect the rigidity of the cylinder head body 1. Moreover, if the value of c is too small, it will be difficult to ensure that the value of d is between 0.2mm and 1mm, which will make assembly difficult. If the c value is too large (greater than 16mm), the fuel injected by the secondary injector 6 will travel a longer path to reach the vicinity of the electrode. This will result in a limited increase in the air-fuel mixture concentration near the electrode, and the effect on improving the ignition stability of the main spark plug 2 will be minimal. In addition, if the c value is too large, the injection pressure of the secondary injector 6 needs to be increased to a very high level, for example, to a level higher than 500 bar, to ensure that the fuel can reach the vicinity of the electrode. However, this will result in very small and low-density fuel particles in the fuel jet 61. The amount of these particles that evaporate into a gaseous state and move to the vicinity of the electrode will still be relatively small, making it difficult to ensure that the air-fuel mixture concentration near the main spark plug 2 is increased to a high level. Furthermore, with the same injection quantity, increasing the injection pressure will result in a smaller injection pulse width required by the secondary injector 6, which will make it difficult to control very small injection pulse widths.

[0077] Optionally, referring to Figures 1 and 4, the oil jet 61 is a conical oil jet 61, and the cone angle β of the conical oil jet is 10° to 18°; and / or, the injection pressure of the auxiliary injector 6 is 350 bar to 500 bar.

[0078] In this embodiment, the centerline of the fuel jet 61 injected by the auxiliary injector 6 is set at an angle to the axis of the main spark plug 2 within the combustion chamber 7. That is, the injection directions (centerline directions of the two fuel jets 61) are towards the position slightly forward and slightly backward directly below the main spark plug 2 (as shown in Figure 4). This allows the fuel in the fuel jet 61 to diffuse more easily and extensively to the electrodes of the main spark plug 2 after evaporation, further ensuring the stability of the main spark plug 2's electrode ignition. Furthermore, the cone angle β of the conical fuel jet is between 10° and 18°, for example, 10°, 16°, or 18°. If it is too small (less than 10°), the diameter of the fuel droplets in the fuel jet 61 will be relatively large, making evaporation and ignition difficult. If it is too large (greater than 18°), the fuel droplets will be too dispersed and have a low density, which may result in insufficient concentration near the electrodes, potentially leading to unstable ignition.

[0079] In this embodiment, the injection pressure of the auxiliary injector 6 is between 350 bar and 500 bar, for example, 350 bar, 400 bar, or 500 bar. If the injection pressure is too high (above 500 bar), the injection pulse width will be reduced, and a smaller injection pulse width is difficult to control. If the injection pressure is too low (below 350 bar), the diameter of the fuel droplets in the fuel jet 61 will be relatively large, making it difficult to evaporate and ignite. Moreover, if the injection pressure is too low, the fuel in the fuel jet 61 may move downwards before reaching the vicinity of the electrode.

[0080] Optionally, referring to Figures 3 and 4, the oil jet 61 is provided with two branches, the included angle α between the center lines of the two oil jets 61 is 20° to 45°, and the two oil jets 61 are symmetrically arranged about the axis of the main spark plug 2.

[0081] In this embodiment, the number of fuel jets 61 sprayed by the auxiliary injector 6 should not be too large, that is, the number of fuel jets 61 should not exceed two. If the number of fuel jets 61 is greater than or equal to three, under the same fuel injection quantity and fuel injection pressure of the auxiliary injector 6, the more fuel jets 61 there are, the smaller the injection pulse width (injection duration) of each fuel jet 61 needs to be designed. Such a small injection pulse width is not only difficult to control, but also easily causes instability in fuel injection before each ignition. For example, when there are many fuel jets 61, the injection pulse width that needs to be controlled is 0.1ms (the crankshaft angle corresponding to this duration is, for example, 5°CA). When controlling this injection pulse width for the first time, the control duration may be 0.9ms, and when controlling it for the second time, it may be 1.1ms.

[0082] Therefore, in this embodiment, the number of fuel jets 61 should not exceed two; for example, there can be two fuel jets 61. When there are two fuel jets 61, as shown in Figure 4, when the two fuel jets 61 are sprayed downwards at an angle, they are distributed one in front of the other on the front and back sides of the main spark plug 2. That is, one fuel jet 61 faces a position slightly forward and directly below the main spark plug 2, and the other faces a position slightly backward and directly below the main spark plug 2. At this time, the center lines of the two fuel jets 61 are set at an angle to the axis of the main spark plug 2 but do not intersect. The angle α between the center lines of the two fuel jets 61 is 20° to 45°, for example, 20°, 45° or 25°. In this way, while ensuring that neither fuel jet 61 interferes with the electrode of the main spark plug 2, it also ensures that there is a higher concentration of air-fuel mixture distributed on the lower front and lower rear sides of the electrode, so that the area of ​​higher concentration air-fuel mixture near the electrode is larger, further improving the ignition stability of the main spark plug 2.

[0083] Optionally, referring to Figures 3 and 6, the oil jet 61 is provided with one branch, and the center line of the oil jet 61 is set at an angle to and intersects the axis of the main spark plug 2, that is, the branch oil jet 61 faces directly below the main spark plug 2.

[0084] In this embodiment, the oil jet 61 can also be a single jet. When the oil jet 61 is a single jet, in order to ensure that there is a large area of ​​rich mixture near the electrode, this single oil jet 61 is located directly below the main spark plug 2, that is, the center line of the oil jet 61 intersects the axis of the main spark plug 2.

[0085] In this case, regardless of whether the fuel jet 61 sprayed by the auxiliary injector 6 is directed towards the position slightly forward and directly below the main spark plug 2, or slightly backward and directly below the main spark plug 2, or directly below the main spark plug 2, it all falls under the category of the spray direction of the auxiliary injector 6 being directed towards the downward side of the main spark plug 2, as mentioned above.

[0086] Among them, the main spark plug 2 can be a high-energy spark plug, which produces a higher energy arc after ignition, a larger area, and makes it easier to ensure ignition stability.

[0087] Another embodiment of the present invention provides an engine including the engine cylinder head as described above.

[0088] Since the technological improvements and effects of the engine are the same as those of the engine cylinder head, the engine will not be described in detail again.

[0089] Another embodiment of the present invention provides an engine control method based on the aforementioned engine, comprising: when the air-fuel ratio of the mixture in the combustion chamber 7 of the engine is lower than or equal to a first set value, controlling the auxiliary spark plug 3 and the main spark plug 2 to ignite simultaneously; and / or, when the air-fuel ratio of the mixture in the combustion chamber 7 is greater than the first set value, controlling the ignition timing of the auxiliary spark plug 3 to be later than that of the main spark plug 2.

[0090] In this embodiment, when the air-fuel ratio of the mixture in the combustion chamber 7 is low, that is, when the concentration of the mixture is not particularly lean, such as when the air-fuel ratio is in the range of 1.4 to 2.0 (e.g., air-fuel ratio of 1.4, 1.5 or 2.0), the mixture at this concentration can be ignited relatively stably by the spark plug. Therefore, the auxiliary spark plug 3 and the main spark plug 2 can be controlled to ignite simultaneously, thereby increasing the combustion speed of the lean mixture in this concentration range and reducing the knock frequency.

[0091] In this embodiment, when the air-fuel ratio of the mixture in the combustion chamber 7 is high, that is, when the mixture concentration is particularly lean, such as when the air-fuel ratio is greater than 2.0, the stability of the mixture ignited by the spark plug is poor, and it may take multiple ignitions to ignite. Therefore, the main spark plug 2 can be controlled to ignite first, and the auxiliary spark plug 3 can be ignited after a certain period of time. For example, the ignition time of the auxiliary spark plug 3 can be delayed by 8°CA to 12°CA compared with the ignition time of the main spark plug 2. In this way, by igniting the main spark plug 2 first, it can be ensured that the main spark plug 2 has already been successfully ignited when the auxiliary spark plug 3 is ignited, which is beneficial to the stable ignition of the auxiliary spark plug 3. Specifically, after the main spark plug 2 is successfully ignited, the mixture has been ignited, forming a flame core that spreads to the surrounding area. The flame core provides a more ignition-friendly environment, that is, the flame core generates heat and high-temperature gas, which can make the ignition of the auxiliary spark plug 3 more stable and easier. Of course, it will also increase the overall combustion speed of the mixture and reduce the knocking frequency.

[0092] Another embodiment of the present invention provides a vehicle comprising the engine as described above.

[0093] Since the technological improvements and effects of the vehicle are the same as those of the engine, the vehicle will not be described in detail again.

[0094] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include at least one of those features.

[0095] While the embodiments of the present invention have been disclosed above, the scope of protection of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention, and all such changes and modifications will fall within the scope of protection of the embodiments of the present invention.

Claims

1. An engine cylinder head, comprising a cylinder head body (1), a main spark plug (2) and an auxiliary spark plug (3), wherein the cylinder head body (1) includes an inner side surface (11), the inner side surface (11) being able to form a combustion chamber (7) by surrounding an engine block (8) and a piston (9) located in the block (8), the main spark plug (2) and the auxiliary spark plug (3) being respectively disposed on the cylinder head body (1), the electrode of the main spark plug (2) and the electrode of the auxiliary spark plug (3) both extending out of the inner side surface (11) of the cylinder head and located in the combustion chamber (7), the electrode of the main spark plug (2) being located at or near the center point of the inner side surface (11) of the cylinder head, and the electrode of the auxiliary spark plug (3) being disposed closer to the edge of the inner side surface (11) of the cylinder head than the main spark plug (2).

2. The engine cylinder head according to claim 1, wherein, The cylinder head body (1) has a symmetrical structure. The main spark plug (2) is located on the symmetrical surface of the cylinder head body (1), and the auxiliary spark plug (3) is disposed on the symmetrical surface or symmetrically distributed relative to the symmetrical surface.

3. The engine cylinder head according to claim 2, wherein, The engine cylinder head is a four-valve cylinder head. There is one auxiliary spark plug (3). The auxiliary spark plug (3) is located between the two intake valves (4) or the two exhaust valves (5) of the four-valve cylinder head, and the auxiliary spark plug (3) is located on the symmetrical surface of the cylinder head body (1); or, there are two auxiliary spark plugs (3). The two auxiliary spark plugs (3) are respectively located between the two intake valves (4) and the corresponding adjacent exhaust valves (5), and the two auxiliary spark plugs (3) are symmetrical about the symmetrical surface of the cylinder head body (1).

4. The engine cylinder head according to claim 3, wherein, The inner side (11) of the cylinder head is provided with valve seats that correspond one-to-one with the two intake valves (4) and the two exhaust valves (5), and the minimum distance e between the auxiliary spark plug (3) and the nearest valve seat is greater than or equal to 3 mm.

5. The engine cylinder head according to claim 1 further includes an auxiliary fuel injector (6) disposed on the cylinder head body (1), the inner side surface (11) of the cylinder head is used to enclose and form a combustion chamber (7), the auxiliary fuel injector (6) is used to spray a fuel jet (61) toward the combustion chamber (7), the injection direction of the fuel jet (61) is toward the electrode of the main spark plug (2), and the fuel jet (61) does not contact the electrode of the main spark plug (2), the fuel jet (61) passes through the lower part of the electrode of the main spark plug (2), and the fuel in the fuel jet (61) can diffuse toward the electrode of the main spark plug (2) after evaporation.

6. The engine cylinder head according to claim 5, wherein, The engine cylinder head is a four-valve cylinder head with a symmetrical structure. The main spark plug (2) is located between the center line connecting the two exhaust valves (5) of the four-valve cylinder head and the center point of the inner side surface (11) of the cylinder head. The auxiliary injector (6) is located between the center line connecting the two intake valves (4) of the four-valve cylinder head and the center point of the inner side surface (11) of the cylinder head.

7. The engine cylinder head according to claim 5, wherein, The oil jet (61) is a conical oil jet with a cone angle β of 10° to 18°; and / or, the injection pressure of the auxiliary injector (6) is 350 bar to 500 bar.

8. The engine cylinder head according to claim 5, wherein, The auxiliary injector (6) injects two oil jets (61), the included angle α between the center lines of the two oil jets (61) is 20° to 45°, and the two oil jets (61) are symmetrically arranged about the axis of the main spark plug (2).

9. The engine cylinder head according to claim 5, wherein, The auxiliary injector (6) injects a jet of oil (61), and the centerline of the jet of oil (61) intersects the axis of the main spark plug (2).

10. The engine cylinder head according to claim 8 or 9 further includes a main injector (10) disposed on the cylinder head body (1), wherein the sum of the injection quantity of the main injector (10) and the injection quantity of the auxiliary injector (6) is the total injection quantity; when there are two oil jets (61), the injection quantity of the auxiliary injector (6) accounts for 5% to 15% of the total injection quantity, and the injection pulse width of the auxiliary injector (6) is 10°CA to 20°CA; when there is one oil jet (61), the injection quantity of the auxiliary injector (6) accounts for 7% to 17% of the total injection quantity, and the injection pulse width of the auxiliary injector (6) is 15°CA to 25°CA.

11. The engine cylinder head according to claim 5, wherein, The cylinder head body (1) is also provided with an air intake passage (12). One end of the air intake passage (12) that is connected to the inner side of the cylinder head body (1) is the air intake port. Let the plane where the axis of the main spark plug (2) is located be the first setting plane. The first setting plane is perpendicular to the plane formed by the axis of the main spark plug (2) and the axis of the auxiliary fuel injector (6). The air intake port and the auxiliary fuel injector (6) are both located on the same side of the first setting plane. The auxiliary fuel injector (6) is closer to the first setting plane than the air intake port. The air delivery direction of the air intake port intersects with the first setting plane. The center line of the fuel jet (61) intersects with the first setting plane.

12. The engine cylinder head according to claim 5, wherein, The electrodes of the main spark plug (2) include a center electrode (22) and a side electrode (21); the minimum gap d between the surface of the oil jet (61) and the side electrode (21) is 0.2 mm to 1 mm; and / or the distance c between the center of one end of the auxiliary injector (6) on the inner side of the cylinder head body (1) and the center electrode (22) is 10 mm to 16 mm.

13. An engine comprising an engine cylinder head as described in any one of claims 1 to 12.

14. A method for controlling an engine, based on the engine of claim 13, comprising: When the air-fuel ratio of the mixture in the combustion chamber (7) of the engine is lower than or equal to the first set value, the auxiliary spark plug (3) and the main spark plug (2) are controlled to ignite simultaneously. And / or, when the air-fuel ratio of the mixture in the combustion chamber (7) is greater than a first set value, the ignition timing of the auxiliary spark plug (3) is controlled to be later than that of the main spark plug (2).

15. A vehicle comprising the engine as claimed in claim 13.

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