Composite turbulence EGR stratified combustion system for gas machine and control method of composite turbulence EGR stratified combustion system

Abstract

The invention discloses a composite turbulent flow EGR stratified combustion system for a gas engine, which comprises a multi-valve composite turbulent flow structure, a rotational flow and turbulent flow mixer and a self-adaptive high-energy ignition system, and the multi-valve composite turbulent flow structure ensures that both a core area flow field and a peripheral area flow field of a combustion chamber have enough turbulent flow intensity; an EGR layered control strategy of an air inlet channel is achieved through air inlet manifold distribution and air channel arrangement, the EGR concentration of a mixture entering a tumble air channel is low, the EGR concentration of a mixture entering a vortex air channel is high, and therefore the space distribution rule of low EGR of a flow field of a combustion chamber core area and high EGR of a flow field of a combustion chamber peripheral area is achieved. Through the synergistic effect of the composite turbulent flow system, EGR layering, intake manifold turbulent flow and self-adaptive high-energy ignition, the comprehensive effects of rapid formation of fire cores at the initial stage of combustion, flame propagation acceleration, reduction of the knocking tendency and enhancement of combustion stability are achieved, and the self-adaptive high-energy ignition system is particularly suitable for popularization and application of natural gas fuel in heavy trucks and ship engines.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to an EGR stratification technology and control method applicable to gas engines for heavy-duty trucks and ships. Background Technology

[0002] Under the "dual carbon" background, natural gas, as a low-carbon fuel, has broad application prospects in the field of heavy-duty engines. However, its slow combustion speed, high heat load, and severe knocking limit its promotion in truck and marine engines.

[0003] To improve the combustion performance of natural gas engines, existing technologies mainly optimize the following aspects:

[0004] Firstly, there's the flow field organization technology based on vortex or tumble flow. Optimizing the intake manifold structure, such as by installing baffles or valves, enhances in-cylinder airflow and accelerates flame propagation. However, in heavy-duty engines with large cylinder diameters and low engine speeds, vortex intensity is difficult to maintain, leading to insufficient turbulent kinetic energy in the core region, slow flame core formation, long combustion duration, and severe afterburning. Simultaneously, organizing the overall tumble flow structure is challenging, and its effectiveness diminishes rapidly with the compression stroke, limiting its coverage in improving combustion.

[0005] Second, there is Exhaust Gas Recirculation (EGR) technology. By introducing EGR, its dilution, heat capacity, and chemical effects are used to suppress knocking and reduce NOx emissions. Existing technologies are mainly divided into two categories. Traditional EGR intake methods pre-mix exhaust gas with fresh air in the intake manifold to form a homogeneous mixture before entering the cylinder. In this method, low EGR rates are ineffective at suppressing knocking, while high EGR rates significantly dilute the mixture near the spark plug, leading to slow flame formation or even misfire, and a sharp decline in combustion stability. To address the combustion degradation problem at high EGR rates, existing technologies have proposed various stratified EGR schemes. For example, introducing a "fuel / air mixture" and an "EGR / air mixture" to create EGR concentration stratification within the cylinder. Alternatively, directly injecting recirculated exhaust gas into the cylinder via an injector, introducing the exhaust gas into the cylinder and forming a stratification with the fresh air entering through the scavenging port. However, the former has a complex structure and the tumble decay problem still exists; although the latter can form EGR stratification and increase the swirl ratio, its main purpose is to reduce NOx, and it does not solve the problem of increased ignition energy demand and difficulty in flame core formation caused by the dilution of the area near the spark plug by exhaust gas under high EGR rate.

[0006] Third, increasing ignition energy or adopting multi-point ignition methods can improve ignition stability under EGR and lean-burn conditions. However, ignition energy cannot dynamically adapt to changes in engine load and speed conditions. Too low ignition energy can easily lead to misfire, while too high ignition energy can easily cause electrode erosion and result in non-uniform flame core unstable combustion.

[0007] In summary, existing technologies suffer from insufficient turbulence in the ignition core region, slow flame core formation, high peripheral gas temperatures leading to easy spontaneous combustion and frequent detonation, high EGR levels resulting in misfires and poor combustion stability. Furthermore, fixed-energy electrode ignition leads to insufficient adaptability and electrode erosion, making it difficult to balance thermal efficiency and detonation suppression. Therefore, achieving effective EGR stratification in gas engines to improve thermal efficiency while suppressing end-gas spontaneous combustion and detonation has become a critical issue that urgently needs to be addressed. Summary of the Invention

[0008] To address the aforementioned existing technologies, this invention provides a composite turbulent EGR stratified combustion technology for gas engines. By coordinating tumble and vortex flows within the composite combustion system, it achieves rapid flame nucleus development in the core flow field and accelerated flame propagation in the peripheral flow field. By employing different EGR concentrations in different intake ducts, it achieves low EGR in the core flow field and high EGR in the peripheral flow field, balancing combustion speed, engine thermal efficiency, and knock suppression. Furthermore, a downstream swirling turbulence mixer improves mixture uniformity, reducing the operational variability among engine cylinders. Combined with adaptive high-energy ignition technology, it ensures stable and efficient combustion across the entire engine load range (especially at high EGR).

[0009] To address the problems of slow combustion speed, prominent knocking issues, and easy misfire at high EGR rates in existing heavy-duty natural gas engines, this invention proposes a composite turbulent EGR stratified combustion system for gas engines. This system includes a multi-valve composite turbulent structure, a swirling turbulence mixer, and an adaptive high-energy ignition system.

[0010] The multi-valve composite turbulence structure is either a two-intake-valve or a three-intake-valve structure. For the two-intake-valve structure, the air passages are arranged such that one side of the intake passage is designed as a tumble-flow passage, with the jet direction pointing towards the spark plug area in the core area of ​​the combustion chamber; the other side of the intake passage is a vortex passage, which causes the air and the circulating exhaust gas to rotate along the cylinder axis and act on the outer perimeter of the combustion chamber. For the three-intake-valve structure, the air passages are arranged such that the middle air passage is a tumble-flow passage, and the two side air passages are vortex passages, ensuring that the flow field in both the core area and the outer perimeter of the combustion chamber has sufficient turbulence intensity.

[0011] The swirling flow mixer includes 6-12 guide vanes arranged along the airflow direction. Each guide vane is spirally arranged around its axis, with adjacent guide vanes having an interleaved angle of 15°-45°, thus forming a multi-scale swirling flow. The curvature and tilt angle of the guide vanes are optimized and adjusted according to the engine flow characteristics. The thickness of the guide vanes is 0.6-1.2mm, and the swirling direction of the guide vanes is selected as clockwise or counterclockwise according to the direction of the vortex in the engine cylinder. The swirling flow mixer is arranged downstream of the intake manifold, near the cylinder head, to ensure that the EGR and fresh air are fully mixed before entering each cylinder.

[0012] The adaptive high-energy ignition system is a dual-channel high-energy ignition coil, including a main ignition coil and an auxiliary ignition coil connected to the spark plug. The three are connected by a wiring harness to establish a real-time signal and energy transmission channel. The state of the main ignition coil and the auxiliary ignition coil is controlled by the engine ECU based on the monitored EGR rate.

[0013] Furthermore, in the composite turbulent EGR stratified combustion system for gas engines described in this invention, wherein:

[0014] The guide vanes adopt a gradually changing tilt angle structure, with the leading edge tilt angle of the vanes being 20°-45° to induce strong swirling flow, and the trailing edge tilt angle of the vanes being 10°-20° to reduce flow resistance.

[0015] When the direction of rotation of the guide vanes is consistent with the direction of the vortex inside the cylinder, it can enhance the stability of the EGR distribution in the vortex region outside the combustion chamber; when the direction of rotation is opposite, it can strengthen the disturbance and diffusion of the tumble direction in the core area of ​​the combustion chamber.

[0016] Meanwhile, this invention also proposes a composite turbulent EGR stratified combustion control method for gas engines, which is implemented using the aforementioned system. The method mainly achieves the intake manifold EGR stratified control strategy through intake manifold distribution and intake channel arrangement, so that the EGR concentration of the mixture entering the tumble intake channel is lower, while the EGR concentration of the mixture entering the vortex intake channel is higher, thereby realizing the spatial distribution law of low EGR in the core area of ​​the combustion chamber and high EGR in the outer perimeter area of ​​the combustion chamber. Specifically, the engine ECU continuously monitors parameters including EGR rate, stoichiometry, and engine load to determine the instantaneous combustion conditions of the engine. When the engine ECU detects that the engine is in a combustion condition with an EGR rate of less than 10% or a stoichiometry of 1.0 ± 0.05, the engine ECU sends a command to the adaptive high-energy ignition system to provide an ignition energy of 90 mJ. When the engine ECU detects that the engine is in a combustion condition with an EGR rate of 10%-30%, a stoichiometry of 0.6-0.9, or an engine load rate ≤ 40% of the rated load, the engine ECU sends a command to the adaptive high-energy ignition system to gradually increase the ignition energy to 160 mJ at a rate of 10-20 mJ / ms.

[0017] Compared with the prior art, the present invention has the following significant advantages:

[0018] (1) Rapid formation of the fire core: core area tumble flow + no EGR or low EGR, the fire core formation time is shortened and the ignition success rate is improved.

[0019] (2) Flame propagation is accelerated and detonation is significantly suppressed: peripheral vortex enhances flame expansion and shortens the combustion duration. Peripheral high EGR suppresses end-stage auto-ignition and improves high EGR tolerance.

[0020] (3) Improved thermal efficiency: Lean combustion combined with EGR stratification strategy achieves a balance between combustion efficiency and stability.

[0021] (4) Improved consistency of each cylinder: The downstream swirling turbulence mixer makes the EGR distribution of each cylinder more uniform, reducing the probability of misfire.

[0022] (5) Enhanced adaptability to all working conditions: It is compatible with heavy truck and marine engines, and can ensure stable combustion under both high and low loads.

[0023] In summary, this invention achieves a comprehensive effect of rapid ignition nucleus formation, accelerated flame propagation, reduced knocking tendency, and enhanced combustion stability through the synergistic effect of "composite turbulence system + EGR stratification + intake manifold turbulence + adaptive high-energy ignition". It is particularly suitable for the promotion and application of natural gas fuel in heavy-duty truck and marine engines. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the combustion system of the present invention;

[0025] Figure 2 This is a schematic diagram of a combustion chamber layout with two intake valves;

[0026] Figure 3 This is a schematic diagram of a three-intake-valve combustion chamber layout;

[0027] Figure 4 This is a schematic diagram of the intake manifold mixer arrangement and the swirling turbulence mixer structure;

[0028] Figure 5 This is a schematic diagram of a dual-channel high-energy ignition coil structure.

[0029] In the diagram: 1-Exhaust passage, 2-Exhaust pipe, 3-Cylinder, 4-Swirl mixer, 5-Swirl intake pipe, 51-Swirl intake pipe A, 52-Swirl intake pipe B, 6-Intake passage, 7-ECU, 8-Spark plug, 9-EGR, 10-High EGR passage, 11-Low EGR passage, 12-Tumble intake pipe, 13-Outer high EGR swirl zone, 14-Piston, 15-Core low EGR swirl zone, 16-Intake mixture, 17-Guide vane, 18-Homogeneous mixture, 19-Recirculating exhaust gas, 20-Main ignition coil, 21-Auxiliary ignition coil. Detailed Implementation

[0030] The design concept of the compound turbulent EGR stratified combustion control method for gas engines proposed in this invention is to achieve stable combustion, suppress knocking and improve thermal efficiency in the full load range of the engine (especially at high EGR) by comprehensively applying a multi-valve compound turbulent structure, intake EGR stratified control, intake manifold swirling turbulence mixer and adaptive high-energy ignition.

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0032] This invention relates to a composite turbulent EGR stratified combustion control method for gas engines. The system implemented by this method includes a multi-valve composite turbulent structure. Through the design of the intake system and valve structure, the coordinated distribution of vortices and tumble flows in the combustion chamber and the stratification of EGR concentration are achieved, thereby ensuring stable and efficient combustion across the full load range of the engine.

[0033] The overall structure of the combustion system in this embodiment is as follows: Figure 1 As shown, the system includes an exhaust manifold 1, an intake manifold 6, and six cylinders 3 in between. Each cylinder is connected to the exhaust manifold 1 via a corresponding exhaust pipe 2 and is connected to the intake manifold 6 via multiple intake pipes. Swirl intake pipes 5 and tumble intake pipes 12 are arranged alternately to create a composite flow field. A swirling diffuser 4 is installed near the cylinder inlet in the intake pipe to enhance the mixing effect. Simultaneously, the EGR device 9 delivers exhaust gas to different intake pipes through high EGR passage 10 and low EGR passage 11, respectively, achieving in-cylinder EGR stratification. Furthermore, each cylinder is equipped with a spark plug 8, which is connected in real-time by the ECU 7 to adaptively adjust the ignition energy according to operating conditions.

[0034] The multi-valve composite turbulence structure is a two-intake-valve or three-intake-valve structure, and the engine adopts a two-intake-valve or three-intake-valve arrangement. Regarding valve arrangement, this invention proposes different composite turbulence organization methods for two-intake-valve and three-intake-valve structures respectively.

[0035] For engines primarily operating under low-load conditions, a dual-intake-valve structure is adopted. In the embodiment, for example... Figure 2 As shown, the core of the dual-intake-valve structure in this embodiment lies in the dual-intake and dual-exhaust valve layout at the top of cylinder 3. The exhaust pipe 2 is located on one side, while the intake side is arranged with the tumble intake pipe 12 and the vortex intake pipe 5 arranged side-by-side. The spark plug 8 is vertically mounted at the center of the cylinder top, at the intersection of the two types of intake pipes. During intake and compression, the airflow entering through the tumble intake pipe 12 directly points to the center of the combustion chamber where the spark plug 8 is located, forming a core low-EGR tumble zone 15 that tumbles around the transverse axis within the cylinder, aiming to promote rapid flame formation through high turbulent kinetic energy. Simultaneously, the vortex intake pipe 5 guides the mixture containing high-concentration exhaust gas tangentially into the cylinder wall, forming a circumferentially rotating peripheral high-EGR vortex zone 13 around the combustion chamber, used to suppress auto-ignition and knocking of the end gases. The piston 14 is located at the bottom of the cylinder and moves upwards, compressing these two types of mixtures with significant concentration and flow field gradients together with the cylinder head, thereby achieving a stratified combustion effect of "stable ignition in the core area and suppression of knocking in the peripheral area."

[0036] For engines with large cylinder bores that need to operate under high load conditions with a high EGR rate of 25%-30% for extended periods, a three-intake valve structure is adopted, such as... Figure 3 As shown in the embodiment, the three-intake-valve structure employs a composite layout of three intake valves and two exhaust valves at the top of cylinder 3 to address the challenges of scavenging and combustion under high loads. The exhaust pipe 2 is located on one side, while the intake side consists of a central tumble intake pipe 12 and symmetrically arranged vortex intake pipes A 51 and B 52 on either side. The spark plug 8 is vertically positioned at the center of the cylinder head. During the intake stroke, the central tumble intake pipe 12 guides the low-concentration EGR mixture directly towards the vicinity of the spark plug 8, forming a core low-EGR tumble zone 15 tumbling around the transverse axis at the center of the combustion chamber, providing a high-turbulence kinetic energy environment for the rapid formation of the spark core. The vortex intake pipes A 51 and B 52 on both sides introduce high-concentration EGR mixture tangentially along the cylinder wall. The vortex intake port outlet is arranged tangentially along the cylinder wall, and the port cross-section adopts a gradually changing design, with an inlet cross-sectional area to outlet cross-sectional area ratio of 1.3-1.5. This structure allows the gas to form a stable circumferential vortex outside the combustion chamber, namely the outer high-EGR vortex zone 13, enhancing flame propagation speed and promoting combustion uniformity. Through the combined design of tumble and vortex, a composite turbulent structure of core tumble + outer vortex is formed in the combustion chamber, achieving a synergistic effect of "stable ignition - rapid propagation - complete combustion".

[0037] EGR gas is first cooled by a cooler, then regulated by an EGR valve before flowing back to a dedicated split channel in the intake manifold, achieving differentiated distribution among different air passages. In this invention, an intake manifold distribution and air passage arrangement implement an intake EGR stratification control strategy, resulting in a lower EGR concentration for the mixture entering the tumble passage and a higher EGR concentration for the mixture entering the vortex passage. This achieves a spatial distribution pattern of low EGR in the combustion chamber core area and high EGR in the outer perimeter area. The low EGR in the core area facilitates rapid flame core formation during initial ignition, while the high EGR in the outer perimeter area effectively suppresses auto-ignition and knock by reducing the end-gas temperature. Compared to existing homogeneous EGR methods, this stratification strategy significantly improves ignition stability and combustion speed while maintaining high EGR tolerance.

[0038] For a two-intake-valve configuration, precise control via a flow divider valve ensures that 70%-80% of the EGR gas is introduced into the swirl channel branch, while the EGR concentration in the tumble channel branch is only 20%-30%, creating a stratified distribution of low EGR in the core area and high EGR in the peripheral area. For a three-intake-valve configuration, the EGR distribution channel within the manifold ensures high EGR concentration in the two swirl channels and low EGR concentration in the middle tumble channel, guaranteeing precise EGR stratification in both the inner and outer periphery of the large-bore engine. During the intake stroke, adjusting the intake valve opening phase—with the tumble channel corresponding to an earlier intake valve opening of 2-3°CA—creates a clear and stable stratified interface between the high-EGR peripheral fluid and the low-EGR core fluid within the combustion chamber: the low-EGR core region is oxygen-rich and highly reactive, conducive to ignition nucleus formation; the high-EGR peripheral region has a lower gas temperature, suppressing end-of-pipe auto-ignition and knocking. This EGR layered structure maintains a stable gradient during the compression and combustion stages, enabling the engine to maintain good combustion stability and knock suppression capabilities even under high EGR conditions.

[0039] To further improve mixing uniformity, this invention arranges a swirling turbulence mixer structure downstream of the intake manifold, near the cylinder head, to ensure thorough mixing of EGR and fresh air before they enter each cylinder. To improve the mixing uniformity of EGR with air and fuel and ensure consistent EGR distribution across cylinders, this invention employs a blade-type swirling turbulence mixer downstream of the intake manifold, such as... Figure 4 As shown in the embodiment, the main body of the swirling mixer 4 is made of aluminum alloy, stainless steel, or high-temperature composite material. Its inlet end receives the intake mixed gas 16 and the circulating exhaust gas 19, while its outlet end outputs a fully mixed homogeneous mixed gas 18. The swirling mixer contains 6-12 spirally arranged guide vanes 17, each 0.6-1.2 mm thick, with an interleaving angle of 15°-45° (preferably 15°-30°) to form multi-scale swirling flow. To balance strong mixing and low pressure loss, the vanes 17 employ a gradually changing tilt angle structure, with a larger leading edge tilt angle of 20°-45° to induce strong swirling flow and a smaller trailing edge tilt angle of 10°-20° to reduce flow resistance. In terms of connection, a sealing gasket is used between the swirling mixer and the intake manifold to prevent EGR concentration deviation due to leakage. The rotation and shearing effects generated when the airflow passes through the blades 17 ensure that the EGR gas and fresh air are fully mixed before entering each cylinder, effectively reducing the EGR concentration deviation between cylinders. Furthermore, the rotation direction of the blades 17 can be set according to the direction of the in-cylinder vortex: consistent rotation enhances the stability of the EGR distribution in the outer vortex region, while opposite rotation intensifies the disturbance in the tumble flow direction of the core region. Through the precise design of this structure, while maintaining a flow coefficient ≥0.95, the mixing uniformity is improved by approximately 25%-30%, significantly improving the combustion consistency of the engine.

[0040] The adaptive high-energy ignition system in this invention relies on the real-time monitoring and precise control of the engine control unit (ECU) for its core operation. The ECU continuously monitors key parameters, including EGR rate, equivalence ratio, and engine load, to determine the instantaneous combustion conditions of the engine and automatically adjusts the ignition energy within the range of 90-160 mJ according to different combustion conditions. To achieve variable ignition energy, the system employs an adaptive high-energy ignition system, such as... Figure 5 As shown, the core hardware of the adaptive high-energy ignition system is a dual-channel high-energy ignition coil system, including a main ignition coil 20, an auxiliary ignition coil 21, an ECU 7, and spark plugs 8. The main ignition coil 20, auxiliary ignition coil 21, and ECU 7 establish a real-time signal and energy transmission channel through a wiring harness. The state of the main ignition coil 20 and auxiliary ignition coil 21 is controlled by the engine ECU based on the monitored EGR rate. The ECU issues commands to the coils through advanced pulse control technology, thereby achieving millisecond-level energy response and dynamically adjusting the ignition energy within the range of 90-160mJ. The specific working principle is as follows:

[0041] The engine ECU continuously monitors parameters including EGR rate, stoichiometry, and engine load to determine the instantaneous combustion conditions of the engine. When the ECU detects a low EGR rate and a mixture close to the stoichiometry, only the main ignition coil 20 is activated, while the auxiliary ignition coil 21 remains in a de-energized dormant state. When the ECU detects a high EGR rate, a lean mixture, or a low cylinder pressure change rate, it activates the full-power coordinated mode of the main ignition coil 20 and auxiliary ignition coil 21. To ensure timely switching between the dual-coil operating modes, the ECU employs millisecond-level dynamic response control logic. If either coil malfunctions, the ECU can immediately detect and switch to a single-coil emergency mode to ensure short-term stable engine operation. Specifically, when the ECU detects that the engine is in a low EGR rate (less than 10%) or a mixture close to the stoichiometry (equivalent ratio close to 1.0), the mixture is easily ignited. In this case, the ECU instructs the adaptive high-energy ignition system to output approximately 90mJ of low energy, which is sufficient to ensure stable combustion and effectively reduce spark plug electrode erosion. However, once the ECU detects that the engine operating conditions have changed to a high EGR rate (10%-30%), a lean air-fuel mixture (equivalent ratio of 0.6-0.9), or a low engine load (load rate ≤ 40% of rated load), the ignition difficulty increases dramatically. The ECU will immediately and automatically switch to high-energy mode, sending energy to the adaptive high-energy ignition system at a rate of 10-20 mJ / ms, gradually increasing the ignition energy to a maximum of 160 mJ. This high-energy input enhances the formation capability of the spark core, effectively avoiding ignition delay and misfire risks under harsh conditions such as high EGR.

[0042] In summary, the integrated application of the multi-valve composite turbulence structure, EGR stratified control strategy, swirling turbulence mixer, and adaptive high-energy ignition system in this invention demonstrates significant combustion improvement effects on the engine under different loads, speeds, and EGR conditions: combustion duration is shortened by 15-20%; knock frequency is reduced by more than 60%; thermal efficiency is increased by 3-6%; EGR deviation between cylinders is reduced by 30%, and combustion consistency is significantly improved. Even at high EGR rates (approximately 25-30%), the engine can still maintain stable combustion and output, achieving high thermal efficiency operation under lean combustion conditions, making it particularly suitable for heavy-duty truck and marine engines powered by natural gas.

[0043] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many improvements and changes under the guidance of the present invention without departing from the spirit of the present invention, and these improvements and changes are all within the protection scope of the present invention.

Claims

1. A composite turbulent EGR stratified combustion system for a gas engine, characterized in that, The system includes a multi-valve composite turbulence structure, a swirling flow mixer, and an adaptive high-energy ignition system. The multi-valve composite turbulence structure is either a two-intake-valve or a three-intake-valve structure. For the two-intake-valve structure, the air passages are arranged such that one side of the intake passage is designed as a tumble-flow passage, with the jet direction pointing towards the spark plug area in the core area of ​​the combustion chamber; the other side of the intake passage is a vortex passage, which causes the air and the circulating exhaust gas to rotate along the cylinder axis and act on the outer perimeter of the combustion chamber. For the three-intake-valve structure, the air passages are arranged such that the middle air passage is a tumble-flow passage, and the two side air passages are vortex passages, ensuring that the flow field in both the core area and the outer perimeter of the combustion chamber has sufficient turbulence intensity. The swirling flow mixer includes 6-12 guide vanes arranged along the airflow direction. Each guide vane is spirally arranged around its axis, with adjacent guide vanes having an interleaved angle of 15°-45°, thus forming a multi-scale swirling flow. The curvature and tilt angle of the guide vanes are optimized and adjusted according to the engine flow characteristics. The thickness of the guide vanes is 0.6-1.2mm, and the swirling direction of the guide vanes is selected as clockwise or counterclockwise according to the direction of the vortex in the engine cylinder. The swirling flow mixer is located downstream of the intake manifold, near the cylinder head, to ensure that the EGR and fresh air are fully mixed before entering each cylinder. The adaptive high-energy ignition system is a dual-channel high-energy ignition coil, including a main ignition coil (20) and an auxiliary ignition coil (21) connected to the spark plug (8). The three establish a real-time signal and energy transmission channel through a wiring harness. The state of the main ignition coil (20) and the auxiliary ignition coil (21) is controlled by the engine ECU according to the monitored EGR rate.

2. The composite turbulent EGR stratified combustion system for gas engines according to claim 1, characterized in that, The guide vanes adopt a gradually changing tilt angle structure, with the leading edge tilt angle of the vanes being 20°-45° to induce strong swirling flow, and the trailing edge tilt angle of the vanes being 10°-20° to reduce flow resistance.

3. The composite turbulent EGR stratified combustion system for a gas engine according to claim 1, characterized in that, When the direction of rotation of the guide vanes is consistent with the direction of the vortex inside the cylinder, it can enhance the stability of the EGR distribution in the vortex region outside the combustion chamber; when the direction of rotation is opposite, it can strengthen the disturbance and diffusion of the tumble direction in the core area of ​​the combustion chamber.

4. A method for stratified combustion control of compound turbulent EGR in gas engines, characterized in that, This method is implemented using the system described in any one of claims 1 to 3; by distributing the intake manifold and arranging the intake passages, an intake passage EGR stratification control strategy is achieved, resulting in a lower EGR concentration of the mixture entering the tumble passage and a higher EGR concentration of the mixture entering the vortex passage, thereby achieving a spatial distribution pattern of low EGR in the core area of ​​the combustion chamber and high EGR in the outer perimeter area of ​​the combustion chamber.

5. The control method according to claim 4, characterized in that, The engine ECU continuously monitors parameters including EGR rate, chemical equivalence ratio, and engine load to determine the instantaneous combustion conditions of the engine. When the engine ECU detects that the engine is in a combustion condition with an EGR rate of less than 10% or an equivalence ratio of 1.0 ± 0.05, the engine ECU sends a command to the adaptive high-energy ignition system with an ignition energy of 90 mJ. When the engine ECU detects that the engine is in a combustion condition with an EGR rate of 10%-30%, an equivalence ratio of 0.6-0.9, or an engine load rate ≤40% of the rated load, the engine ECU sends a command to the adaptive high-energy ignition system to gradually increase the ignition energy to 160mJ at a rate of 10-20 mJ / ms.

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