An efficiently coupled microwave-assisted integrated spark plug

Abstract

The present invention belongs to the field of internal combustion engine combustion, and specifically discloses a highly efficient coupled microwave-assisted integrated spark plug, which includes a ceramic body, a circuit component and a metal shell. The ceramic body is generally in a T shape or a tree branch shape as a whole, and includes a main path of the ceramic body and ceramic body branch paths on the sides; the tail end of the main path of the ceramic body is connected to a microwave generating device, and a ceramic body skirt is provided at the front end of the main path of the ceramic body; the circuit component includes a branch electrode and a main path electrode which are connected, the branch electrode is connected to an external power supply, and a center electrode is provided at the front end of the main path electrode; the branch electrode, the main path electrode and the center electrode are respectively sleeved inside the ceramic body branch path, the main path of the ceramic body and the ceramic body skirt; the metal shell is sleeved outside the main path of the ceramic body, and a grounding electrode is provided at the front end of the metal shell, and the grounding electrode is opposite to the front end of the center electrode to jointly form an ignition electrode. The present invention does not require modification of the engine structure, and can overcome problems such as difficult ignition of conventional spark plugs and unstable fire nuclei under extreme working conditions.

Description

Technical Field

[0001] The present invention belongs to the field of internal combustion engine combustion, and more specifically, relates to a highly efficient coupled microwave-assisted integrated spark plug. Background Art

[0002] In the field of internal combustion engine technology, lean combustion makes the mixture burn more fully by using a high air-fuel ratio and a high compression ratio, becoming an effective means to improve fuel economy, reduce fuel consumption and emission levels; in addition, the application of some low-carbon and carbon-free fuels, such as ammonia fuel, can effectively reduce CO2 emissions and become an important direction of the dual-carbon strategy. However, in these operating conditions such as lean combustion and ammonia fuel application, there are problems such as difficult ignition of conventional spark plugs and unstable fire nuclei, which need to be solved urgently.

[0003] Increasing the ignition energy is one of the effective means to solve the above problems. However, simply increasing the ignition energy will cause ablation of the spark plug, thus reducing the service life of the ignition system. In recent years, the ignition technology and ignition devices based on microwave plasma have gradually shown their potential. Among them, microwave resonant torch ignition and microwave resonant cavity ignition use microwaves to resonate in the local electrode or combustion chamber to form a strong electric field to break down the mixture gas for ignition, and have certain application potential.

[0004] Chinese Patent CN102080619B proposes an engine ignition device based on microwave plasma. Through the setting of coupling the waveguide with the cylinder, when the piston moves to a certain position, microwave resonance is formed in the cylinder, thereby exciting the plasma to catch fire. It is difficult to break down the mixture gas only by using the strong electric field generated by microwave resonance in a high-pressure environment, so this method has great instability. The patent also mentions that a spark plug can be considered as a pre-ionization device, which further illustrates the difficulty of breaking down the mixture gas only by using microwave resonance. Therefore, the microwave-assisted ignition technology (MAI) provides a beneficial solution to solve the ignition problem under the above operating conditions.

[0005] In the microwave-assisted ignition technology, the high-voltage electricity of the spark plug breaks down the mixed gas, and then microwave energy is fed into the breakdown discharge, so that the initial discharge plasma cluster rapidly diffuses outwards, strengthening the ignition process. This scheme combines the advantages of traditional spark plug ignition and microwave plasma ignition and has strong practicability.

[0006] Chinese Patent CN106762331A proposes a microwave-assisted spark plug ignition method and an integrated device. By sending pulse signals to the spark plug system and the microwave system respectively, the two systems generate pulsed high-voltage electricity and microwave pulses with specific frequencies and powers. The two pulses are integrated through a mixer device and finally break down the mixture gas at the two electrodes. However, this design has a separate mixer, and the spark plug structure is a conventional spark plug, resulting in a relatively large volume of the entire system, making it difficult to install on an engine. At the same time, it is difficult to focus the microwave energy, and the microwave-assisted effect is relatively low. Therefore, this method has certain difficulties in practical applications.

[0007] Chinese Patent CN102797612A proposes a microwave plasma ignition coupling device for internal combustion engines - namely, a microwave spark plug, which breaks down the mixture gas through microwave electrodeless discharge at the inner conductor coupling end to achieve the purpose of stable ignition for lean combustion. However, this simple microwave electrodeless ignition method is difficult to successfully ignite under high ambient pressure and cannot be truly applied in internal combustion engines. Summary of the Invention

[0008] In view of the above defects or improvement requirements of the prior art, the present invention provides a highly coupled microwave-assisted integrated spark plug, aiming to meet the stable ignition requirements under extreme working conditions such as lean combustion of engines or engines using carbon-free fuels without the need to modify the engine structure, and to overcome problems such as difficult ignition and unstable fire kernels caused by conventional spark plugs under extreme working conditions.

[0009] To achieve the above object, the present invention proposes a highly coupled microwave-assisted integrated spark plug, including a ceramic body, a circuit component, and a metal shell, wherein:

[0010] The ceramic body is generally in a T shape or a tree branch shape, and includes a main path of the ceramic body and a branch path of the ceramic body provided on the side of the main path of the ceramic body; the tail end of the main path of the ceramic body is connected to a microwave generating device, and a ceramic body skirt is provided at the front end of the main path of the ceramic body.

[0011] The circuit component includes a branch electrode and a main path electrode connected to each other. The branch electrode is connected to an external high-voltage power supply, and a center electrode is provided at the front end of the main path electrode; the branch electrode, the main path electrode, and the center electrode are respectively sleeved inside the branch path of the ceramic body, the main path of the ceramic body, and the ceramic body skirt.

[0012] The metal shell is sleeved outside the main path of the ceramic body, and a protruding grounding electrode is provided at the front end of the metal shell. The grounding electrode is opposite to the front end of the center electrode, and together they form an ignition electrode.

[0013] As a further preferred option, the main path of the ceramic body and the metal shell are in a coaxial structure.

[0014] As a further preference, the inner side of the skirt of the ceramic body, i.e., the side in contact with the central electrode, is streamlined.

[0015] As a further preference, the cross-section of the skirt of the ceramic body gradually decreases.

[0016] As a further preference, a resistor body is connected to the branch electrode.

[0017] As a further preference, an elliptical protrusion is provided on the grounding electrode, and the minor axis of the elliptical protrusion is opposite to the central electrode; the inside of the elliptical protrusion is made of the metal material of the grounding electrode, and a precious metal is plated on the outside.

[0018] As a further preference, the central electrode is needle-shaped, the inside thereof is an electrically good conductor, the outside is wrapped with nickel, and a precious metal or its alloy is plated on the head.

[0019] As a further preference, the ratio of the outer diameter of the ceramic body branch to the outer diameter of the branch electrode is 1.8:1 to 3:1.

[0020] As a further preference, the ceramic body is an electrically insulating microwave conductor, which is made of a ceramic material or a polytetrafluoroethylene material.

[0021] As a further preference, an external front thread is provided on the outer side of the front part of the metal shell for fixing the spark plug on the cylinder; an external sealing ring is provided at the rear of the external front thread; an internal sealing ring is provided between the maximum diameter at the tail end of the skirt of the ceramic body and the metal shell.

[0022] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the following technical advantages are mainly available:

[0023] 1. Through the design of a T-shaped or tree-shaped structure, the present invention realizes the coupling of high-voltage breakdown and microwave feeding in the same spark plug; thus, the advantages of traditional spark plug high-voltage discharge to break down the air-fuel mixture and microwave coupling energy to plasma are combined on one spark plug, which can realize stable ignition under some extreme working conditions, and solve the problems of difficult ignition and unstable flame caused by lean combustion and carbon-free fuel combustion at present. At the same time, it is not necessary to modify the combustion chamber of the existing engine, and it can be interchanged with a conventional spark plug, and the replacement cost is low.

[0024] 2. It changes the idea of the straight-line propagation of high-voltage electricity and the side-feed of microwaves in traditional microwave coupling devices. The microwave circuit and the outer shell of the spark plug form a coaxial structure, achieving the effect of nearly straight-line coaxial transmission of microwaves. At the same time, through the streamlined transmission design of the microwave circuit, the along-way dissipation of microwaves is reduced, significantly improving the microwave transmission efficiency. At the same time, since the loss of high-voltage electricity is mainly related to resistance and has nothing to do with the path, the propagation of the high-voltage circuit from the side path will not generate additional high-voltage circuit losses. This coupling method can obviously better improve the microwave transmission efficiency and the microwave-assisted ignition efficiency.

[0025] 3. The insulator skirt is wrapped around the front part of the center electrode, which is convenient for concentrating microwave energy between the two electrodes and enhancing the coupling effect between microwaves and high-voltage electricity. At the same time, the insulator skirt plays a role in heat dissipation and can reduce the burning loss of the ignition electrode.

[0026] 4. The ceramic body skirt at the front end of the microwave circuit adopts the method of gradually reducing the transmission cross-sectional area to achieve the effect of gradually concentrating microwaves, which is convenient for microwaves to finally be concentrated and radiated between the ignition electrodes. At the same time, using a shorter ceramic body skirt can reduce the formation of a local high-energy area of microwave energy, thereby reducing the excessive dissipation of microwave energy.

[0027] 5. Since the continuous multiple ignitions of the spark plug can generate microwaves of other frequencies, which are different from the frequencies of the transmitted microwaves and will cause great interference. Therefore, the resistor body closer to the ignition electrode in the traditional spark plug is changed to the T-shaped branch on the side. On the one hand, it can eliminate the loss of energy in the microwave transmission process by the resistor in the circuit, and on the other hand, it can prevent the high-voltage electricity from interfering with the normal operation of other electrical appliances and reduce the erosion of the spark plug electrode by the discharge current.

[0028] 6. The grounding electrode is provided with an elliptical protrusion, and the material of the elliptical protrusion is also a composite material, with the metal material of the grounding electrode inside and a precious metal plated on the outside; this elliptical protrusion design can not only control the high-voltage breakdown path and improve the ignition stability, but also the outside is plated with a precious metal layer, which can reduce the corrosion caused by electron avalanche.

[0029] 7. The center electrode adopts a composite material, with a conventional good electrical conductor such as a copper core selected inside, and a precious metal or its alloy such as nickel wrapped on the outside and platinum or iridium plated on the head. This can not only improve the heat dissipation ability but also improve the antioxidant ability to cope with the ablation problem of high-energy ignition.

[0030] 8. A small amount of microwaves will escape to the branch at the confluence of the main branch. The present invention can adjust the escape ability of microwaves to the ceramic body branch by designing the ratio of the outer diameter of the ceramic body branch to the outer diameter of the branch electrode, realizing the minimal escape of microwaves to the branch, so that the microwaves mainly propagate on the ceramic body main path, thereby improving the microwave transmission efficiency on the ceramic body main path.

[0031] 9. The integrated spark plug is wrapped with a metal shell, which is a poor conductor of microwaves and can effectively prevent the microwaves transmitted in the microwave line from diffusing outward and causing losses. At the same time, it can also prevent the influence of external electromagnetic interference on the microwave transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the highly coupled microwave-assisted integrated spark plug according to an embodiment of the present invention;

[0033] Figure 2 Cross-sectional view of the junction of the microwave line and the high-voltage line in the microwave-assisted integrated spark plug according to an embodiment of the present invention;

[0034] Figure 3 Partial enlarged schematic diagram of the ignition electrode in the microwave-assisted integrated spark plug according to an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of the connection structure between the microwave connector and the RF interface in the microwave-assisted integrated spark plug according to an embodiment of the present invention.

[0036] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - ceramic body, 11 - ceramic body branch, 12 - ceramic body main path, 13 - ceramic body skirt, 21 - main path electrode, 22 - branch path electrode, 23 - center electrode, 24 - connection point, 25 - branch path electrode terminal, 31 - external sealing ring, 32 - internal sealing ring, 41 - rear half of the metal shell, 42 - front half of the metal shell, 43 - hexagon nut, 44 - front end external thread, 45 - ground electrode, 46 - rear end internal thread, 5 - ignition electrode, 51 - ignition anode, 52 - ignition cathode, 6 - RF interface, 7 - resistor body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] A highly coupled microwave-assisted integrated spark plug provided by an embodiment of the present invention includes a microwave line, a high-voltage line, an ignition electrode, a high-voltage sealing and fixing assembly.

[0039] The overall shape of the spark plug is a T-shaped (or tree branch-shaped) structure, as Figure 1As shown, the microwave circuit is placed in the main part of the T-shaped structure of the spark plug. The microwave circuit path is an approximately straight line, which can improve the microwave transmission efficiency, realize the efficient input of microwaves and the efficient energy collection of microwaves, and radiate the microwaves to the ignition area between the spark plug electrodes. At the same time, in order to meet the requirements of efficient microwave transmission, the high-voltage electric circuit is designed to the side of the spark plug. The high-voltage electric circuit transmits high voltage electricity to the ignition electrode with minimal energy consumption, generates a strong electric field between the two electrodes of the spark plug, and breaks down the combustible mixture. The microwave circuit and the high-voltage electric circuit do not interfere with each other, and finally couple at the spark plug ignition electrode, thereby enhancing the ignition ability of the spark plug and realizing stable ignition under extreme working conditions.

[0040] Specifically:

[0041] In the microwave circuit, the internal material is a high-voltage electrical insulator microwave conductor. As an excellent conductor of microwaves, it can reduce the loss during microwave transmission. At the same time, as an electrical insulator, it can prevent high-voltage electricity from breaking through the spark plug. It is preferably made of ceramic material, that is, the main part of the microwave circuit is the connected ceramic body main path 12 and the ceramic body skirt 13. The ceramic body skirt 13 is arranged at the front end of the ceramic body main path 12. The cross-section of the ceramic body skirt 13 gradually decreases, and the transmission cross-sectional area of the microwave circuit gradually decreases, thereby achieving the effect of gradually collecting microwave energy, which is convenient for the microwave to be finally concentrated and radiated between the ignition electrodes. In the microwave circuit, the outside is a metal shell, which is tightly matched with the ceramic body main path 12. The ceramic body main path 12 and the metal shell form a coaxial structure. The microwave is fed through the coaxial transmission line and propagates in the ceramic body and enters the microwave circuit. At the same time, due to the gradual decrease in the cross-section of the ceramic body skirt 13, there is a certain gap between the front end of the metal shell and the ceramic body skirt 13.

[0042] Furthermore, the metal shell includes a front half section 42 and a rear half section 41 of the metal shell; a rear end internal thread 46 is provided inside the rear end of the rear half section 41 of the metal shell for connecting the rear end of the spark plug to the radio frequency interface 6, such as Figure 4 As shown, the RF interface 6 is connected to the microwave transmission coaxial line, and the other end of the microwave transmission coaxial line is connected to the microwave source. The microwave enters the spark plug through the RF interface 6, passes through the ceramic body main path 12, and is finally fed into the ignition interval between the two electrodes by air at the ceramic body skirt 13. The insulator skirt 13 also plays a role in heat dissipation.

[0043] Furthermore, a DC block is provided between the microwave source and the radio frequency interface, which can effectively ensure that the high voltage electricity of the high voltage power line will not be transmitted to the microwave source through the microwave line, thereby preventing the high voltage electricity from damaging the microwave source and ensuring the safe use of the spark plug.

[0044] Furthermore, the microwave circuit and the outer shell of the spark plug form a coaxial structure, achieving the effect of microwave transmission close to a straight line coaxially. The cross-section of the microwave circuit is streamlined, and large-curvature rounded corners are made at the turning points. That is, the side in the ceramic body skirt 13 that contacts the center electrode 23 is streamlined, which can significantly reduce the along-way loss of microwaves.

[0045] Furthermore, the microwave circuit is connected to the microwave generation and control system through a microwave connector. This system includes a magnetron, a magnetron drive coil, a microwave transmission coaxial cable, etc. Specifically: the magnetron generates microwaves with a specific frequency and power. Generally, the microwave frequency is about 2.45 GHz, and the power can be selected as 1000 W; the magnetron drive coil generates the electrical signal required to drive the magnetron; the above devices can be connected by a microwave transmission coaxial cable to realize the transmission of microwaves from the microwave source to the spark plug.

[0046] Furthermore, the metal shell, as a poor conductor of microwaves, can effectively prevent the microwaves transmitted in the microwave circuit from diffusing outward and causing loss. At the same time, it can also prevent the influence of external electromagnetic interference on the microwave transmission system.

[0047] The high-voltage circuit is a bent circuit, placed on the side of the overall spark plug. The internal material is a metal conductor, and the metal conductor transmits high-voltage electricity to the ignition electrode; the outer material is an electrical insulator, such as ceramics. The electrical insulator can effectively block the safety problem caused by the high-voltage electricity breaking down the air. Specifically, the inside of the high-voltage circuit is a circuit component. The circuit component includes a branch electrode 22 and a main electrode 21 connected. Among them, as Figure 2 shown, the branch electrode 22 is on the side. One side is connected to the high-voltage electricity through the branch electrode terminal 25, and the other side is connected to the main electrode 21 through the connection point 24; the main electrode 21 is on the main path, and its front end is provided with a center electrode 23; the branch electrode 22, the main electrode 21, and the center electrode 23 are respectively sleeved inside the ceramic body branch 11, the ceramic body main path 12, and the ceramic body skirt 13. The high-voltage electricity is fed in from the branch electrode terminal 25 and reaches the center electrode 23 successively through the branch electrode 22 and the main electrode 21. The external ceramic body 1 ensures its safety.

[0048] Furthermore, a resistor body 7 is provided in the high-voltage circuit. The resistor body 7 is located on the outer side of the high-voltage circuit far from the microwave circuit. Since the spark plug can generate microwaves of other frequencies during continuous multiple ignitions, these microwaves have different frequencies from the transmitted microwaves (2.45 GHz) and will cause great interference. Therefore, the resistor body in the traditional spark plug that is closer to the spark plug ignition electrode is changed to the high-voltage transmission line, that is, the T-shaped branch. On the one hand, it can eliminate the loss of energy in the microwave transmission process caused by the resistance in the circuit. On the other hand, it can prevent the high-voltage electricity from interfering with the normal operation of other electrical appliances and reduce the erosion of the spark plug electrode by the discharge current.

[0049] Further, the outer diameter ratio of the ceramic body branch 11 to the branch electrode 22 is 1.8:1 to 3.0:1. By adjusting the outer diameter ratio of the ceramic body branch to the branch electrode, the microwave dissipated in the ceramic body branch can be made extremely small and negligible, so that the microwave mainly propagates in the main ceramic body path, improving the transmission efficiency of the microwave in the ceramic body.

[0050] The ignition electrode 5 includes a center electrode 23 and a ground electrode 45. As Figure 3 shown, the center electrode 23 is energized with high voltage through a high-voltage power line; the ground electrode 45 is welded to the front end of the metal shell, in an L shape, and the ground electrode 45 is connected to the engine with a voltage of 0; an ignition anode 51 and an ignition cathode 52 are oppositely arranged on the center electrode 23 and the ground electrode 45 to achieve ignition.

[0051] Further, the center electrode 23 is in a needle tip shape to control the breakdown path. The center electrode material is a composite material. A conventional good electrical conductor such as a copper core is selected inside, nickel is wrapped outside, and a noble metal or its alloy such as platinum or iridium is plated at the head. This not only improves the heat dissipation ability but also can improve the antioxidant ability to cope with the ablation problem of high-energy ignition. An elliptical protrusion is provided on the ground electrode 45. The material of the elliptical protrusion is also a composite material. The inside is the metal material of the ground electrode, and a noble metal is plated outside; the short axis of the ellipse is opposite to the center electrode. This design of the elliptical protrusion can not only control the high-voltage breakdown path, improve the ignition stability, but also reduce the corrosion caused by electron avalanche.

[0052] The high-voltage sealing and fixing assembly includes an outer sealing ring 31, an inner sealing ring 32 and a hexagonal nut 43. An outer front thread 44 is provided on the outer side of the front half 42 of the metal shell for fixing the spark plug on the cylinder. The outer sealing ring 31 is installed behind the outer front thread 44; the inner sealing ring 32 is arranged between the head of the ceramic body and the head of the metal shell; the hexagonal nut 43 is arranged in the middle of the metal shell. This regular hexagonal protruding structure can facilitate the use of tools such as a hexagonal wrench to screw the spark plug into the cylinder for fixing.

[0053] The following are specific embodiments:

[0054] The material of the ceramic body 1 is 95% alumina ceramic. The materials of the main path electrode 21, the branch electrode 22 and the connection point 24 between the main path electrode and the branch electrode are all copper. The outer surface adopts a nickel plating process. The inner material of the center electrode 23 is copper, the outer material is nickel alloy. The material of the metal shell is nickel alloy. The materials of the ignition anode 51 and the ignition cathode 52 are platinum-iridium alloy.

[0055] The inner sealing ring 32 is made of expanded graphite, which has the characteristics of high temperature resistance and corrosion resistance. In the spark plug, this structure will completely fill the gap between the sealing ceramic body and the metal shell, thereby preventing high-temperature gases and fuel stains from entering the gap and causing damage to the ignition device.

[0056] The feasibility of the embodiment was further determined through simulation. The external environment was set by imitating the cylinder environment in the simulation software as follows: temperature 1000K, pressure 10 atm. High-voltage electricity of a specified magnitude and microwaves with a frequency of 2.45 GHz and a power of 1000 W were respectively input into the interfaces of the high-voltage electricity transmission line and the microwave transmission line.

[0057] The results are as follows: The average value of the microwave electric field between the two electrodes can reach 5.4×105 V / m. In addition, the high-voltage electricity does not affect the transmission effect of the microwaves, and the synchronous transmission of microwaves and high-voltage electricity does not affect each other.

[0058] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An efficiently coupled microwave-assisted integrated spark plug, characterized in that, It includes a ceramic body (1), a circuit component, and a metal housing, where: The ceramic body (1) is generally in a T shape or a tree branch shape as a whole, and it includes a main path of the ceramic body (12) and a branch path of the ceramic body (11) arranged on the side of the main path of the ceramic body (12); the tail end of the main path of the ceramic body (12) is connected to a microwave generating device, and a skirt of the ceramic body (13) is arranged at the front end of the main path of the ceramic body (12); the cross-section of the skirt of the ceramic body (13) gradually decreases; The circuit component includes a connected branch electrode (22) and a main path electrode (21), the branch electrode (22) is connected to an external high-voltage power supply, and a resistor body (7) is connected to the branch electrode (22); a center electrode (23) is connected to the front end of the main path electrode (21); the branch electrode (22), the main path electrode (21), and the center electrode (23) are respectively sleeved inside the branch path of the ceramic body (11), the main path of the ceramic body (12), and the skirt of the ceramic body (13); The metal housing is sleeved outside the main path of the ceramic body (12), and a protruding grounding electrode (45) is arranged at the front end of the metal housing, and the grounding electrode (45) is opposite to the front end of the center electrode (23) to jointly form an ignition electrode (5).

2. The highly efficient coupled microwave-assisted integrated spark plug according to claim 1, wherein, The main path of the ceramic body (12) and the metal housing are in a coaxial structure.

3. The highly efficient coupled microwave-assisted integrated spark plug according to claim 1, characterized in that, The inner side of the skirt of the ceramic body (13), that is, the side in contact with the center electrode (23), is streamlined.

4. The highly efficient coupled microwave-assisted integrated spark plug according to claim 1, wherein An elliptical protrusion is arranged on the grounding electrode (45), and the minor axis of the elliptical protrusion is opposite to the center electrode (23); the inside of the elliptical protrusion is the metal material of the grounding electrode (45), and a precious metal is plated on the outside.

5. The highly efficient coupling microwave-assisted integrated spark plug according to claim 4, characterized in that, The center electrode (23) is in a needle tip shape, its inside is a good electrical conductor, it is wrapped with nickel on the outside, and a precious metal or its alloy is plated on the head.

6. The highly efficient coupling microwave-assisted integrated spark plug according to claim 1, wherein The ratio of the outer diameter of the branch path of the ceramic body (11) to the outer diameter of the branch electrode (22) is 1.8:1 to 3:

1.

7. The highly efficient coupled microwave-assisted integrated spark plug according to claim 1, wherein The ceramic body (1) is an electrical insulator microwave conductor, and it is made of a ceramic material or a polytetrafluoroethylene material.

8. The highly efficient coupled microwave-assisted integrated spark plug according to any one of claims 1-7, characterized in that, An external front thread (44) is arranged on the outer side of the front part of the metal housing for fixing the spark plug on the cylinder; an external sealing ring (31) is arranged behind the external front thread (44); an internal sealing ring (32) is arranged between the metal housing and the maximum diameter at the tail end of the skirt of the ceramic body (13).

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