MPI supply system based on cross-cylinder air passage

Abstract

The MPI supply system based on the cross-cylinder air channel comprises the cross-cylinder air channel and a fuel supply assembly, the cross-cylinder air channel is provided with an air inlet end and two air outlet ends, and the two air outlet ends of the cross-cylinder air channel communicate with two adjacent air cylinders of an engine; the fuel supply assembly is provided with a fuel supply end arranged in the cross-cylinder air channel, and the fuel supply end is configured to enable supplied fuel to be conveyed into the corresponding air cylinder through one air outlet end. The two adjacent air cylinders of the engine are communicated through the cross-cylinder air channel, based on the ignition sequence of the engine and by means of the characteristic that air cannot be fed into the two adjacent air cylinders at the same time, it can be guaranteed that fuel can be supplied to each air cylinder through the fuel supply end during air feeding and ignition of the air cylinders, and due to the design, multi-point injection can be achieved, the number of needed nozzles can be greatly reduced, and the injection efficiency is improved. And meanwhile, the complexity of the system is reduced, potential fault points are reduced, and the failure risk and the operation and maintenance cost can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of engine fuel supply, and in particular to an MPI supply system based on a cross-cylinder air passage. Background Art

[0002] The engine fuel supply system mainly includes single-point injection, multi-point injection and direct injection. Among them, the working principle of multi-point injection (MPI) is to install an injector in front of the intake valve of each cylinder, and the fuel can be directly injected in front of the intake valve of each cylinder and mixed with the air before entering the cylinder.

[0003] The MPI supply system can provide more precise fuel control for each cylinder of the engine, thereby optimizing combustion efficiency and engine performance, effectively improving the engine's power and fuel economy, while reducing emissions.

[0004] However, the large number of nozzles in the MPI supply system increases production costs, while also increasing system complexity and potential failure points, making maintenance difficult and increasing long-term operating costs. Summary of the invention

[0005] In view of this, it is necessary to provide an MPI supply system based on cross-cylinder air ducts to solve the problems of large number of nozzles in the MPI supply system, increased production costs, increased system complexity and potential failure points, difficult maintenance, and increased long-term operating costs.

[0006] The present invention provides an MPI supply system based on a cross-cylinder air passage, comprising a cross-cylinder air passage and a fuel supply assembly, wherein the cross-cylinder air passage has an intake end and two outlet ends, and the two outlet ends of the cross-cylinder air passage are connected to two adjacent cylinders of the engine; the fuel supply assembly has a fuel supply end built into the cross-cylinder air passage, and the fuel supply end is configured so that the supplied fuel can be delivered to the corresponding cylinder via one of the outlet ends.

[0007] Furthermore, the fuel supply assembly comprises a nozzle guide tube, one end of which is used for externally connecting fuel, and the other end of which is a fuel supply end and extends into the cross-cylinder air passage.

[0008] Furthermore, the air inlet end points to one of the air outlet ends to form a first air inlet passage, the air inlet end points to the other air outlet end to form a second air inlet passage, and the nozzle guide pipe is arranged at a position between the first air inlet passage and the second air inlet passage.

[0009] Furthermore, an auxiliary intake duct and two exhaust ducts are also provided on the cylinder of the engine, and a first center plane passing through the axis of the cylinder is provided between the first intake duct and the second intake duct and the adjacent auxiliary intake duct.

[0010] Further, the first intake duct and the second intake duct each have a first straight line segment, a first arc segment and a second straight line segment connected in sequence on one side in the projection of the first center plane and in the direction close to the cylinder, the angle θ2 between the first straight line segment and the top surface of the cylinder is in the range of 0° to 15°, the angle R1 of the first arc segment is in the range of 80 mm to 100 mm, and the angle θ1 between the second straight line segment and the top surface of the cylinder head is in the range of 40° to 60°; The first air intake duct and the second air intake duct have a third straight line segment, a second arc segment and a fourth straight line segment connected to each other on the side away from the cylinder head. The angle θ4 between the third straight line segment and the top surface of the cylinder is in the range of 20° to 40°, the angle R2 of the second arc segment is in the range of 80mm to 100mm, and the angle θ3 between the fourth straight line segment and the top surface of the cylinder is in the range of 30° to 50°.

[0011] Furthermore, the angle θ5 between the nozzle guide pipe and the top surface of the cylinder is in the range of 30° to 70°.

[0012] Further, the cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both arc-shaped air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in a direction away from a line connecting the two cylinder heads. The bending direction of the auxiliary air intake passage is the same as that of the adjacent first air intake passage or the second air intake passage. The distance between the two exhaust passages gradually decreases in a direction away from the cylinder head and the two exhaust passages converge and communicate.

[0013] Further, the cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both arc-shaped air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads. The structure of the auxiliary air intake passage is the same as that of the cross-cylinder air passage. The distance between the two exhaust passages gradually decreases in a direction away from the cylinder head and the two exhaust passages converge and communicate.

[0014] Further, the cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head; the first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both straight air passages; the distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads; the auxiliary air intake passage is a straight air passage; The two exhaust passages are both straight air passages and are arranged parallel to each other.

[0015] Further, the cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both straight air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads. The structure of the auxiliary air intake passage is the same as that of the cross-cylinder air passage. The two exhaust passages are both straight air passages and are arranged parallel to each other.

[0016] Compared with the existing technology, the cross-cylinder air duct connects two adjacent cylinders of the engine. Based on the ignition sequence of the engine and utilizing the characteristic that the two adjacent cylinders will not intake air at the same time, it can ensure that when each cylinder intakes air and ignites, there is a fuel supply end to provide it with fuel. This design can not only realize multi-point injection, but also greatly reduce the number of required nozzles and reduce production costs. At the same time, it reduces the complexity of the system and reduces potential failure points, which can effectively reduce the risk of failure and operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the overall arrangement of an MPI supply system based on a cross-cylinder airway provided in an embodiment of the present invention; Figure 2 A schematic diagram of a structure in which a cross-cylinder air passage and a fuel supply assembly are installed on a cylinder in an MPI supply system based on a cross-cylinder air passage provided in an embodiment of the present invention; Figure 3 A schematic diagram of the overall structure of a first embodiment of an MPI supply system based on a cross-cylinder air passage provided in an embodiment of the present invention; Figure 4 A schematic diagram of the overall structure of a second embodiment of an MPI supply system based on a cross-cylinder air passage provided in an embodiment of the present invention; Figure 5 A schematic diagram of the overall structure of a third embodiment of an MPI supply system based on a cross-cylinder air passage provided in an embodiment of the present invention; Figure 6 A schematic diagram of the overall structure of a fourth embodiment of an MPI supply system based on a cross-cylinder air passage provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0019] like Figure 1 As shown, the present invention provides an MPI supply system based on a cross-cylinder air passage, including a cross-cylinder air passage 100 and a fuel supply assembly 200, the cross-cylinder air passage 100 has an intake end 110 and two outlet ends 120, the two outlet ends 120 of the cross-cylinder air passage M are connected to two adjacent cylinders M of the engine; the fuel supply assembly 200 has a fuel supply end built into the cross-cylinder air passage 100, and the fuel supply end is configured so that the supplied fuel can be delivered to the corresponding cylinder M via one of the outlet ends 120.

[0020] During implementation, two adjacent cylinders M of the engine are connected through the cross-cylinder air duct 100. Based on the ignition sequence of the engine and taking advantage of the fact that two adjacent cylinders will not intake air at the same time, it can be ensured that when each cylinder M intakes air and ignites, there is a fuel supply end to provide it with fuel. This design can not only realize multi-point injection, but also greatly reduce the number of required nozzles and reduce production costs. At the same time, it reduces the complexity of the system and reduces potential failure points, which can effectively reduce the risk of failure and operation and maintenance costs.

[0021] The cross-cylinder air passage 100 in this embodiment is connected to the cylinder head of the engine cylinder M. The cross-cylinder air passage 100 has an intake end 110 and two outlet ends 120. The two outlet ends 120 of the cross-cylinder air passage M are connected to two adjacent cylinders M of the engine.

[0022] The air inlet end 110 points to one of the air outlet ends 120 to form a first air inlet passage, and the air inlet end 110 points to the other air outlet end 120 to form a second air inlet passage. The nozzle guide pipe is arranged between the first air inlet passage and the second air inlet passage.

[0023] The fuel supply assembly 200 in this embodiment has a fuel supply end built into the cross-cylinder air passage 100 , and the fuel supply end is configured to supply fuel that can be delivered to the corresponding cylinder M via one of the air outlet ends 120 .

[0024] In one embodiment, the fuel supply assembly 200 includes a nozzle guide tube, one end of which is used to connect external fuel, and the other end of the nozzle guide tube is a fuel supply end and extends into the cross-cylinder air passage.

[0025] Fuel can be added into the cross-cylinder air passage 100 through the nozzle guide pipe, and the fuel can be delivered to the corresponding cylinders M alternately according to the intermittent opening characteristics of two adjacent cylinders M.

[0026] Among them, there is a mixing structure in the part where the nozzle guide tube extends into the cross-cylinder air passage 100. The above mixing structure is mainly the injection holes at the end of the nozzle guide tube. The injection holes with corresponding hole numbers, hole diameters and hole position distribution can be adaptively set according to design requirements.

[0027] It should be noted that the cylinder M of the engine is also provided with an auxiliary intake passage M1 and two exhaust passages M2 , and a first center plane passing through the axis of the cylinder M is defined between the first intake passage and the second intake passage and the adjacent auxiliary intake passage M1 .

[0028] like Figure 2 As shown, the first air intake passage and the second air intake passage in this embodiment both have a first straight line segment, a first arc segment and a second straight line segment connected in sequence on one side in the projection of the first center plane and close to the cylinder M. The angle θ2 between the first straight line segment and the top surface of the cylinder M is in the range of 0° to 15°, the angle R1 of the first arc segment is in the range of 80mm to 100mm, and the angle θ1 between the second straight line segment and the top surface of the cylinder head is in the range of 40° to 60°.

[0029] Among them, the first intake duct and the second intake duct have a third straight line segment, a second arc segment and a fourth straight line segment connected to each other on the side away from the cylinder head. The angle θ4 between the third straight line segment and the top surface of the cylinder M is in the range of 20° to 40°, the angle R2 of the second arc segment is in the range of 80mm to 100mm, and the angle θ3 between the fourth straight line segment and the top surface of the cylinder M is in the range of 30° to 50°.

[0030] The included angle θ5 between the nozzle guide pipe and the top surface of the cylinder M is in the range of 30° to 70°.

[0031] In a first embodiment: like Figure 3 As shown, the cylinder head of cylinder M is a flat-top cylinder head; the cross-cylinder air duct 100 and the auxiliary intake duct M1 are both tumble air ducts and are both connected to the cylinder head, the first intake duct and the second intake duct are connected to the two adjacent cylinder heads and are both arc-shaped air ducts, the distance between the first intake duct and the second intake duct gradually decreases in the direction away from the line connecting the two cylinder heads, and the bending direction of the auxiliary intake duct M1 is the same as that of the adjacent first intake duct or second intake duct; the distance between the two exhaust ducts M2 gradually decreases in the direction away from the cylinder head and converges and connects.

[0032] Among them, the two exhaust ports M2 gradually approach each other in the direction away from the cylinder head. The two exhaust ports M2 can not only provide for the discharge of tumble flow, but also help to discharge the chaotic vortex that may exist in the cylinder M smoothly. Together with the two cross-cylinder air ports 100 and the auxiliary intake port M1, the tumble flow field in the cylinder M can be effectively assembled.

[0033] In the second embodiment: like Figure 4 As shown, the cylinder head of cylinder M is a flat-top cylinder head; the cross-cylinder air duct 100 and the auxiliary intake duct M1 are both tumble air ducts and are both connected to the cylinder head, the first intake duct and the second intake duct are connected to two adjacent cylinder heads and are both arc-shaped air ducts, the distance between the first intake duct and the second intake duct gradually decreases in the direction away from the line connecting the two cylinder heads, and the structure of the auxiliary intake duct M1 is the same as that of the cross-cylinder air duct 100; the distance between the two exhaust ducts M2 gradually decreases in the direction away from the cylinder head and converge and connect.

[0034] Among them, the cross-cylinder air passage 100 and the auxiliary intake passage M1 are symmetrically distributed along the first center plane, and the flow path and flow velocity of the gas entering the cylinder M from the cross-cylinder air passage 100 and the auxiliary intake passage M1 are the same. The impact center of the mixed fuel gas entering from the two routes is located in the middle of the cylinder M, and the impact position corresponds to the spark plug, avoiding the deviation of the impact center of the two routes of gas, making the tumble flow formed in the cylinder M more stable, and both mixed fuel gases can impact the spark plug.

[0035] Among them, the two exhaust ports M2 gradually approach each other in the direction away from the cylinder head. The two exhaust ports M2 can not only provide for the discharge of tumble flow, but also help to discharge the chaotic vortex that may exist in the cylinder M smoothly. Together with the two cross-cylinder air ports 100 and the auxiliary intake port M1, the tumble flow field in the cylinder M can be effectively assembled.

[0036] In the third embodiment: like Figure 5 As shown, the cylinder head of cylinder M is a flat-top cylinder head; the cross-cylinder air duct 100 and the auxiliary intake duct M1 are both tumble air ducts and are both connected to the cylinder head; the first intake duct and the second intake duct are connected to two adjacent cylinder heads and are both straight air ducts; the distance between the first intake duct and the second intake duct gradually decreases in the direction away from the line connecting the two cylinder heads; the auxiliary intake duct M1 is a straight air duct; the two exhaust ducts M2 are both straight air ducts and are arranged parallel to each other.

[0037] Among them, the mixed gas after combustion in the combustion chamber is discharged from the two exhaust ducts M2. The design of the separated dual exhaust duct M2 can reduce exhaust resistance, reduce pumping loss, and improve energy utilization. Since the cross-cylinder air duct 100 and the auxiliary intake duct M1 are arranged relative to the dual exhaust duct M2, the airflow organization is relatively smooth, which is also beneficial to the improvement of the tumble ratio, which is conducive to accelerating combustion and improving thermal efficiency.

[0038] In the fourth embodiment: like Figure 6As shown, the cylinder head of cylinder M is a flat-top cylinder head; the cross-cylinder air duct 100 and the auxiliary intake duct M1 are both tumble air ducts and are both connected to the cylinder head, the first intake duct and the second intake duct are connected to the two adjacent cylinder heads and are both straight air ducts, the distance between the first intake duct and the second intake duct gradually decreases in the direction away from the line connecting the two cylinder heads, the structure of the auxiliary intake duct M1 is the same as that of the cross-cylinder air duct 100; the two exhaust ducts M2 are both straight air ducts and are arranged parallel to each other.

[0039] Among them, the cross-cylinder air passage 100 and the auxiliary intake passage M1 are symmetrically distributed along the first center plane, and the flow path and flow velocity of the gas entering the cylinder M from the cross-cylinder air passage 100 and the auxiliary intake passage M1 are the same. The impact center of the mixed fuel gas entering from the two routes is located in the middle of the cylinder M, and the impact position corresponds to the spark plug, avoiding the deviation of the impact center of the two routes of gas, making the tumble flow formed in the cylinder M more stable, and both mixed fuel gases can impact the spark plug.

[0040] Among them, the mixed gas after combustion in the combustion chamber is discharged from the two exhaust ducts M2. The design of the separated dual exhaust duct M2 can reduce exhaust resistance, reduce pumping loss, and improve energy utilization. Since the cross-cylinder air duct 100 and the auxiliary intake duct M1 are arranged relative to the dual exhaust duct M2, the airflow organization is relatively smooth, which is also beneficial to the improvement of the tumble ratio, which is conducive to accelerating combustion and improving thermal efficiency.

[0041] Of course, the cross-cylinder air passage 100, the auxiliary intake passage M1 and the exhaust passage M2 can also be implemented in other shapes and structures to efficiently distribute the fuel to the corresponding cylinders M and discharge it after being fully burned.

[0042] Workflow: like Figure 1As shown, the MPI supply system based on the cross-cylinder air passage 100 is applied to a six-cylinder four-stroke engine. The six cylinders M on the engine are 1 cylinder, 2 cylinder, 3 cylinder, 4 cylinder, 5 cylinder and 6 cylinder from left to right. The ignition sequence of the engine is 1 cylinder-5 cylinder-3 cylinder-6 cylinder-2 cylinder-4 cylinder. When cylinder 1 is intake, the fuel supply assembly 200 located between cylinders 1 and 2 performs fuel injection, cylinder 2 is in compression and power stroke, the intake valve of cylinder 2 is closed, and the intake valve of cylinder 1 is opened to realize the supply of cylinder 1; when cylinder 2 is intake, the fuel supply assembly 200 arranged between cylinders 1 and 2 performs fuel injection, cylinder 1 is in power and exhaust stroke, the intake valve of cylinder 1 is closed, and the intake valve of cylinder 2 is opened to realize the supply of cylinder 2; when cylinder 3 is intake, the fuel supply assembly 200 arranged between cylinders 3 and 4 is arranged The fuel supply assembly 200 performs fuel injection, the 4th cylinder is in the power stroke, the 4th cylinder intake valve is closed, and the 3rd cylinder intake valve is opened, so as to realize the supply to the 3rd cylinder; when the 4th cylinder is inhaling, the fuel supply assembly 200 arranged between the 3rd and 4th cylinders performs fuel injection, the 3rd cylinder is in the power stroke, the 3rd cylinder intake valve is closed, and the 4th cylinder intake valve is opened, so as to realize the supply to the 4th cylinder; when the 5th cylinder is inhaling, the fuel supply assembly 200 arranged between the 5th and 6th cylinders performs fuel injection, the 6th cylinder is in the power and exhaust stroke, the 6th cylinder intake valve is closed, and the 5th cylinder intake valve is opened, so as to realize the supply to the 5th cylinder; when the 6th cylinder is inhaling, the fuel supply assembly 200 arranged between the 5th and 6th cylinders performs fuel injection, the 5th cylinder is in the compression and power stroke, the 5th cylinder intake valve is closed, and the 6th cylinder intake valve is opened, so as to realize the supply to the 6th cylinder. Thus, for a six-cylinder four-stroke internal combustion engine adopting a multi-point injection system, two adjacent cylinders can realize the common fuel supply assembly 200 described in this patent proposal.

[0043] It is worth mentioning that when cylinders 2 and 5 are intake, there is an exhaust stroke between cylinders 1 and 6. Depending on the camshaft design of different models, there may be a valve overlap period where the intake valves open early. The injection timing strategy and camshaft profile design can be optimized to avoid the low probability of two adjacent cylinders opening the intake valves at the same time.

[0044] Compared with the prior art: by connecting two adjacent cylinders M of the engine through the cross-cylinder air duct 100, based on the ignition sequence of the engine and utilizing the characteristic that the two adjacent cylinders will not intake air at the same time, it can ensure that when each cylinder M intakes air and ignites, there is a fuel supply end to provide it with fuel. This design can not only realize multi-point injection, but also greatly reduce the number of required nozzles and reduce production costs. At the same time, it reduces the complexity of the system and reduces potential failure points, which can effectively reduce the risk of failure and operation and maintenance costs.

[0045] Of course, this optimized nozzle arrangement (the nozzle guide pipe extends to the end structure in the cross-cylinder air passage 100) not only simplifies the system structure, but also improves the overall reliability. As the number of nozzles is reduced, the complexity and potential failure points of the system are also reduced, which is of great significance for improving the stability and durability of the engine. In addition, this design is also widely applicable. It is not only suitable for natural gas engines, but also can be applied to hydrogen engines, thus providing a flexible solution for engines with different fuel types.

[0046] At the same time, in specific applications, this nozzle arrangement can be flexibly set on the cylinder head and intake manifold to meet the requirements of different engine designs. Whether it is a swirl airway or a tumble airway, this design can perfectly match it, ensuring efficient fuel injection under different airway designs. At the same time, it is also compatible with different intake pipe designs such as cover type and manifold type, further broadening its application range.

[0047] In summary, this cross-cylinder air duct 100 nozzle arrangement scheme not only achieves the dual goals of cost-effectiveness and reliability improvement, but also demonstrates excellent adaptability and flexibility, providing an innovative optimization path for the multi-point injection system of natural gas and hydrogen engines.

[0048] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0049] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific conditions.

[0051] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0052] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An MPI supply system based on cross-cylinder airways, characterized in that: include: A cross-cylinder air passage, which has an air inlet end and two air outlet ends, wherein the two air outlet ends of the cross-cylinder air passage are connected to two adjacent cylinders of the engine; The fuel supply assembly has a fuel supply end built into the cross-cylinder air passage, and the fuel supply end is configured to supply fuel that can be delivered to the corresponding cylinder via one of the air outlet ends.

2. The MPI supply system based on cross-cylinder air passage according to claim 1 is characterized in that: The fuel supply assembly comprises a nozzle guide tube, one end of which is used for externally connecting fuel, and the other end of which is a fuel supply end and extends into the cross-cylinder air passage.

3. The MPI supply system based on cross-cylinder airway according to claim 2 is characterized in that: The air inlet end points to one of the air outlet ends to form a first air inlet passage, and the air inlet end points to the other air outlet end to form a second air inlet passage. The nozzle guide pipe is arranged at a position between the first air inlet passage and the second air inlet passage.

4. The MPI supply system based on cross-cylinder air passage according to claim 3 is characterized in that: The cylinder of the engine is also provided with an auxiliary intake passage and two exhaust passages. The first intake passage and the second intake passage each have a first center plane passing through the axis of the cylinder between the adjacent auxiliary intake passages.

5. The MPI supply system based on cross-cylinder air passage according to claim 4 is characterized in that: The first intake duct and the second intake duct each have a first straight line segment, a first arc segment and a second straight line segment connected in sequence on one side in the projection of the first central plane and in the direction close to the cylinder, the angle θ2 between the first straight line segment and the top surface of the cylinder is in the range of 0° to 15°, the angle R1 of the first arc segment is in the range of 80 mm to 100 mm, and the angle θ1 between the second straight line segment and the top surface of the cylinder head is in the range of 40° to 60°; The first air intake duct and the second air intake duct have a third straight line segment, a second arc segment and a fourth straight line segment connected to each other on the side away from the cylinder head. The angle θ4 between the third straight line segment and the top surface of the cylinder is in the range of 20° to 40°, the angle R2 of the second arc segment is in the range of 80mm to 100mm, and the angle θ3 between the fourth straight line segment and the top surface of the cylinder is in the range of 30° to 50°.

6. The MPI supply system based on cross-cylinder air passage according to claim 5 is characterized in that: The included angle θ5 between the nozzle guide pipe and the top surface of the cylinder is in the range of 30° to 70°.

7. The MPI supply system based on cross-cylinder air passage according to claim 4 is characterized in that: The cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both arc-shaped air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in a direction away from a line connecting the two cylinder heads. The bending direction of the auxiliary air intake passage is the same as that of the adjacent first air intake passage or the second air intake passage. The distance between the two exhaust passages gradually decreases in a direction away from the cylinder head and the two exhaust passages converge and communicate.

8. The MPI supply system based on cross-cylinder air passage according to claim 4 is characterized in that: The cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both arc-shaped air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads. The structure of the auxiliary air intake passage is the same as that of the cross-cylinder air passage. The distance between the two exhaust passages gradually decreases in a direction away from the cylinder head and the two exhaust passages converge and communicate.

9. The MPI supply system based on cross-cylinder air passage according to claim 4, characterized in that: The cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head; the first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both straight air passages; the distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads; the auxiliary air intake passage is a straight air passage; The two exhaust passages are both straight air passages and are arranged parallel to each other.

10. The MPI supply system based on cross-cylinder air passage according to claim 4, characterized in that: The cylinder head of the cylinder is a flat-top cylinder head; The cross-cylinder air passage and the auxiliary air intake passage are both tumble air passages and are both connected to the cylinder head. The first air intake passage and the second air intake passage are connected to two adjacent cylinder heads and are both straight air passages. The distance between the first air intake passage and the second air intake passage gradually decreases in the direction away from the line connecting the two cylinder heads. The structure of the auxiliary air intake passage is the same as that of the cross-cylinder air passage. The two exhaust passages are both straight air passages and are arranged parallel to each other.

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