467 results about "Spark plug" patented technology

An ammonia-rich combustion coupled dual-mode prechamber ammonia-fueled engine control system is provided, including an ammonia-fueled engine and an electronic control unit. The ammonia-fueled engine includes a combustion chamber, a dual-mode jet ignition device, and an ammonia injector. The dual-mode jet ignition device includes a prechamber, an air injector, and a fuel injector. When the engine operates, ammonia fuel is firstly injected into the combustion chamber by the ammonia injector to form a rich ammonia-air mixture with air in the combustion chamber. During a compression stroke of the engine, the rich ammonia-air mixture in the combustion chamber is entered into the prechamber through a jet hole. The air injector performs scavenging in the prechamber until a equivalence ratio of prechamber gas mixture is less than 1.0, and then the fuel injector injects fuel into the prechamber forming target mixture. Finally, the target mixture is ignited by the spark plug.

The invention relates to the technical field of engines, and discloses a rotor engine without an intake and exhaust overlapping angle, which comprises a cylinder body, two sides of the cylinder body are respectively provided with an end cover I and an end cover II, the inner wall of the cylinder body and two corresponding side surfaces of the end cover I and the end cover II form a combustion chamber, and an eccentric shaft is arranged on the end cover I and the end cover II in a penetrating manner; the surface, located in the combustion chamber, of the eccentric shaft is sleeved with a center gear, a rotor is arranged in the combustion chamber, the inner wall of the rotor is connected with an inner ring gear, and the inner ring gear is meshed with the center gear. The gas inlet and the gas outlet are respectively arranged on the cylinder body and the end cover, and are matched with alternate opening and closing of the door structure, so that a gas inlet and gas outlet overlapping angle is thoroughly eliminated, residual waste gas is prevented from flowing back to the gas inlet, sufficient gas inlet is ensured, sufficient mixed gas supply is combined with efficient ignition of a spark plug, the combustion efficiency can be improved, and fuel oil waste caused by insufficient combustion is reduced; and the power output of the engine is enhanced.

SOLUTION: A spark plug (1) having a longitudinal axis X, comprising: a housing (2) having a longitudinal bore parallel to the longitudinal axis X of the spark plug (1), whereby the housing (2) has a housing wall (20) and an internal space (21); an insulator (3) disposed inside the housing (2); a center electrode (4) disposed inside the insulator (3); and an overall length L MaEI and D MaEI a ground electrode (5) having a diameter of D Bohr The hole (50) in the housing wall (20) has a diameter of 1.5 mm, and the ground electrode (5) has a length L Bohr The ground electrode (5) is disposed in the hole (50) with a length L em The housing wall (20) projects from the inner surface (20a) of the housing wall (20) into the interior space (21) of the housing (2) with a thickness D Wall and a spark gap (45) formed between the ground electrode (5) and the center electrode (4), and a length L of the ground electrode (5) in the hole (50). Bohr The total length L of the ground electrode (5) MaEI is greater than or equal to 1.8 and less than or equal to 2.2, and / or the thickness L of the housing wall (20) Wall The length L of the ground electrode (5) projecting into the internal space (21) of the housing (2) relative to the em The ratio is greater than or equal to 0.2 and less than or equal to 3, and the length or thickness extends perpendicular to the major axis X of the spark plug (1).

The present application relates to a kind of fuel power device, the center wheel is connected by output shaft in the center through hole of shell, the circumference of center wheel is equipped with several power blocks;Several rotors are equipped on the outer periphery of center wheel, each rotor is matched with the independent space of shell by bearing seat, each rotor is linked with output shaft by transmission mechanism I;Several oblique tooth grooves are equipped on the rotor, power block passes from tooth groove when rotor is tangent with center wheel and runs, the shell corresponding to each rotor, power block and air inlet forms explosion chamber when power block passes from tooth groove, spark plug is provided at air inlet, so that explosion chamber is filled with a certain proportion of air and fuel gas and produces blasting, and power block is pushed;Several exhaust ports are provided on the surface of shell, and exhaust port is staggered with explosion chamber.This power device forms closed chamber by carousel transmission structure, and makes fuel mixture gas blast production power, so as to realize the production of power source.

The application discloses a device and method for adjusting the radial installation angle of the jet hole of a precombustion chamber spark plug, which comprises a sleeve, a sleeve extension rod and a torque wrench, the sleeve extension rod is connected with the sleeve, the torque wrench is arranged on the upper portion of the sleeve extension rod, the sleeve is an outer hexagonal sleeve, and the device further comprises an angle pointer and an angle scale dial, the angle scale dial is fixed on a cylinder head, and the angle pointer is buckled on the sleeve extension rod and located above the angle scale dial. The device increases the angle pointer and the angle scale dial on the basis of the sleeve extension rod and the torque wrench, can adjust the jet hole angle of the precombustion chamber spark plug, and makes the jet hole of the precombustion chamber spark plug be at an angle more favorable to the combustion in the cylinder.

The invention relates to the field of mower control systems, and discloses a gasoline mower cutter soft start control system which comprises an engine, a spark plug, a cutter and an electromagnetic clutch coil which are arranged in a mower shell. The input signal acquisition module, the level conversion and shaping circuit, the single chip microcomputer and the power driving execution module are electrically connected with the spark plug. The single chip microcomputer comprises a rotating speed calculation unit and a core control unit, the rotating speed calculation unit is used for calculating the rotating speed of an engine according to digital pulses output by the level conversion and shaping circuit, and the core control unit selects a soft start control parameter set according to the rotating speed of the engine and outputs a multi-stage PWM control signal to the power driving execution module; the working current of the electromagnetic clutch coil is adjusted by the power driving execution module in stages, soft starting of the cutting knife from a static state to a working rotating speed is achieved, and mechanical impact and vibration in the starting process are reduced.

A spark plug (1, 201, 301, 401, 501, 601) comprising: a cylindrical insulator (10, 210, 410, 510) with an axially extending axial hole (20, 220, 520) and a rearwardly directed surface (22A) formed in the axial hole (20, 220, 520); a cylindrical metal casing (30, 330, 630) arranged on an outer periphery of the insulator (10, 210, 410, 510); and a central electrode (50) arranged at a front end in the axial hole (20, 220, 520), wherein the central electrode (50) has a large-diameter section (52) with an outer diameter that is the largest in the central electrode (50), the large-diameter section (52) being held at the rearward-facing surface (22A), and wherein the metal shell (30, 330, 630) has a diameter-enlarged section (36) at a rear end with respect to the central electrode (50),wherein the enlarged diameter section (36) has an inner diameter that is enlarged towards the rear end, wherein the insulator (10, 210, 410, 510) has a first section (70, 270, 470, 570) which is a section of the insulator (10, 210, 410, 510) in a region (AR) from a rear end of the rearward-facing surface (22A) to a front end of the enlarged diameter section (36), the first section (70, 270, 470, 570) having a thickness (X1) which is the greatest in the region (AR), and is arranged at least on an outer periphery of the large-diameter section (52), the insulator (10, 210, 410, 510) being connected to the metal shell (30, 330, 630) by a seal (45) is held at the front face with respect to the first section (70, 270, 470, 570) and the insulator (10, 210, 410, 510) has a second section (80, 280, 480, 580) at the rear end face with respect to the first section (70, 270, 470, 570) in the area (AR),wherein the second section (80, 280, 480, 580) has an outer diameter (B) that is smaller than an outer diameter (A) of the first section (70, 270, 470, 570), wherein the first section (70, 270, 470, 570) is arranged at least at an outer periphery of an entire region in the axial direction of a section of the central electrode (50) that is arranged in the region (AR).

The invention belongs to the technical field of fuel gas generators, and discloses a combustion chamber of a fuel gas generator. The gas generator combustion chamber comprises a combustion chamber front section and a combustion chamber rear section which are sequentially connected from front to back through a flange plate. A hydrogen spray hole and a spark plug are arranged at the front section of the combustion chamber, the spark plug ignites hydrogen, an oxidizing agent and fuel in main flow are ignited through hydrogen flames, and the hydrogen flow is controlled to be suitable for different ignition working conditions; two paths of body air are arranged at the rear section of the combustion chamber, and flame stability in the combustion chamber is achieved through flow matching of the two paths of body air; meanwhile, the ignition function of the igniter and the flame stabilizing function of the flame stabilizer are integrated on the combustion chamber of the fuel gas generator, the complexity of the fuel gas generator is reduced, the space size is reduced, and the fuel gas generator can be suitable for application scenes with the limited installation space size. The flow calculation method is simple and reliable and has engineering practical value.

A spark plug (38) includes: a spark plug housing (40); a cathode (62) including at least one electrode fork (64) and formed primarily of iridium; and an anode (72) formed at least predominantly of iron or steel. The material composition of the cathode and anode provides extended spark plug service life, especially in high power density applications employing pre-chamber spark plugs. Related methods are also disclosed.

The utility model belongs to the technical field of motorcycle engines, and relates to an air cylinder head structure of a motorcycle engine, which comprises an air cylinder head, a cam shaft is arranged at the top of the air cylinder head, a timing chain wheel is sleeved on the cam shaft, a combustion chamber is arranged below the cam shaft, and a decompression ejector rod for ejecting an exhaust valve open is arranged in the cam shaft in a sliding mode. A centrifugal mechanism for driving the decompression ejector rod to slide is arranged on the timing chain wheel, a first sparking plug and a second sparking plug which are inclined are arranged on the left side and the right side of the combustion chamber respectively, and the included angle between the second sparking plug and the bottom plane of the air cylinder head is smaller than that between the first sparking plug and the bottom plane of the air cylinder head. The air cylinder head is provided with an avoiding groove for avoiding the timing chain wheel and a sleeve base extending in the direction of the avoiding groove, and a sleeve for installing a second spark plug is arranged in the sleeve base. The cylinder head structure of the motorcycle engine is compact in layout, stable in structure and capable of achieving the purpose of further saving energy and reducing consumption.

The utility model relates to the technical field of motorcycle part machining, in particular to motorcycle cylinder head spark plug tapping equipment. Comprising a tapping machine body and a material receiving mechanism, and the material receiving mechanism comprises a belt conveyor, a material receiving barrel, an inclined guide plate, a first limiting block, a second limiting block, a positioning plate, a clamp table, a limiting plate, a receiving device and a limiting device. A spark plug is clamped and conveyed to a clamp of the clamp table through the feeding robot to be fixed, then a part can be subjected to tapping machining through the tapping machine body after being fixed, the part is taken through the feeding robot after tapping is completed, the workpiece is placed on a conveying belt of the belt conveyor, the workpiece is conveyed into the material receiving barrel through the belt conveyor, and the material receiving barrel is used for receiving the spark plug. And then the parts fall onto the inclined guide plate and slide into the receiving device to be automatically collected, feeding machining can be carried out during collection, and therefore the machining efficiency can be improved when motorcycle cylinder head sparking plug tapping machining is carried out.

The invention relates to the field of power engineering. The present internal combustion engine comprises a housing in which a drum and a rotor are rotatably disposed. The rotor comprises a hollow shaft and an impeller wheel. The axis of rotation of the rotor is upwardly offset from the axis of rotation of the drum, the latter providing for the formation of an annular liquid seal by means of a working fluid during rotation. The impeller wheel is configured to be capable of forming alternating combustion and compression chambers. The hollow shaft has a stator arranged coaxially therein such that the cavity between the shaft and the stator can be divided into a fuel mixture supply zone and coolant supply and discharge zones. Mounted in the combustion chambers are spark plugs, each of which comes into contact with a capsule which is spring-loaded by a high-voltage contact and is fastened in a vertical upward position to the cylindrical surface of a rod arranged inside the hollow stator such as to permit regulation of the ignition timing. The rotor and the stator are configured with channels, baffles, ports and a plate, which provide for the supply and discharge of coolant to and from an annular cavity. The technical result is an increase in the efficiency and service life of the engine.

A gasket (20) configured to be positioned between a spark plug and a cylinder head of an internal combustion engine when a threaded section of the spark plug is screwed to the cylinder head. The gasket includes an annular body (23) and projections (25). The annular body is arranged around a threaded relief section of the spark plug where no threads are formed near the threaded section. Each of the projections extends radially inward from the annular body.The annular body, the thread relief section and the threaded section are shaped such that they satisfy a relationship of φb mm ≤ φa mm ≤ φc mm - 0.9 mm, where φa is an inner diameter of a circle (S1) defined to extend along the inner surfaces of the projecting ends (26a) of the inclined sections and centered on an annular center point (Cp) of the annular body, φb is the outer diameter of the thread relief section and φc is the nominal thread diameter of the threaded section.

The invention relates to the technical field of electric spark igniters, in particular to a micro-motion type gasoline engine electric spark igniter and a using method thereof.The micro-motion type gasoline engine electric spark igniter comprises a fixing sleeve and a threaded rotating rod rotationally arranged in the fixing sleeve, the end, extending to the upper side of the fixing sleeve, of the threaded rotating rod is fixedly connected with a check block, and the bottom end of the threaded rotating rod is fixedly connected with a lifting insertion block; a spark plug body is installed in the lifting insertion block, and an upper pole piece and a lower pole piece are arranged at the bottom end of the spark plug body. According to the micro-motion type gasoline engine electric spark igniter, due to the arrangement of the disassembling and assembling mechanism, when the spark plug body is disassembled and assembled, only the balancing weight needs to be pulled and rotated, disassembling and assembling are rapid and convenient, workers do not need to stretch into the spark plug body to disassemble the spark plug body, and efficiency is improved; and if the butt joint of the lower pole piece and the upper pole piece is seriously corroded, the discharging part of the lower pole piece can be automatically replaced, and during subsequent maintenance, a worker can quickly confirm the use condition of each spark plug body.

A spark plug for a spark ignited reciprocating internal combustion engine includes a mounting portion and an ignition portion. One or more surfaces of the ignition portion are at least partially coated with a thermal barrier coating.

Spark plug for a spark-ignition engine. Spark plug (10) for a spark-ignition engine comprising: - a first electrode (1), - a second electrode (2), - a third electrode (13), - a fourth electrode (23), - a first inter-electrode gap (14) located between the first electrode (1) and the third electrode (13), - a second inter-electrode gap (24) located between the second electrode (2) and the fourth electrode (23), and - a base (8), particularly in the lower part of the spark plug, the third and fourth electrodes (13, 23) forming part of the base (8). Figure for the abbreviation: 1

The utility model relates to the field of oil and gas exploitation, in particular to a blowout pool for a sulfur-containing gas well, which comprises a combustion cylinder, an ignition system and a spraying system. And the combustion cylinder is arranged in the blowout pool body and is communicated with the tail end of the blowout pipeline. The ignition system comprises a spark plug, and the spark plug is located above the combustion cylinder. The spraying system comprises a spraying pipe, the spraying pipe is located above the open flow pool body, the spraying pipe is used for spraying alkaline liquid, and the spraying range of the spraying pipe can cover the whole open flow pool body. The spraying system capable of spraying the alkaline liquid is arranged above the blowout pool body, so that the alkaline liquid and hydrogen sulfide gas leaked from the combustion cylinder are subjected to neutralization reaction, and leakage and diffusion of the hydrogen sulfide gas can be effectively reduced.

The invention provides an oil injection control method of an ignition system, a storage medium and a vehicle, and belongs to the technical field of vehicles. The method comprises the steps that the current working condition type of an engine is determined based on the engine rotating speed and driver demand torque; an oil injection strategy corresponding to the current working condition type is determined; and based on the fuel injection strategy, the first fuel injector and the second fuel injector are controlled to conduct fuel injection operation. According to the embodiment of the invention, the distances among the first fuel injector, the second fuel injector and the sparking plug are reasonably arranged, and meanwhile, according to the current working condition type of the engine, a proper fuel injection strategy is specifically matched to control the first fuel injector and the second fuel injector to carry out fuel injection matching, so that mixed gas can be distributed more reasonably and ignited more easily; no matter what working condition the engine is in, stable ignition of the engine and stable combustion of flames can be achieved, and meanwhile the lean combustion effect is improved.

The utility model discloses a spark plug and an internal combustion engine, and belongs to the technical field of spark plugs. The spark plug comprises a shell, a pipe assembly and an electrode assembly. The shell is provided with an accommodating cavity; the pipeline assembly comprises an air inlet pipe and an air outlet pipe. The containing cavity communicates with the air inlet pipe and the air outlet pipe. The electrode assembly is arranged in the containing cavity and comprises a first electrode and a second electrode, a through hole is formed in the second electrode, an internal thread is arranged on the hole wall of the through hole, the first electrode penetrates through the through hole, an external thread is arranged on the circumferential wall of the first electrode, and the rotating direction of the external thread is opposite to that of the internal thread; or, the hole wall of the through hole is provided with a plurality of convex parts which are arranged in an array, and the first electrode is arranged in the through hole in a penetrating manner. According to the spark plug provided by the invention, the number of the discharge points is multiplied, so that the probability of failure of the ignition function of the spark plug is reduced, the service life of the spark plug is prolonged, and the maintenance or replacement cost of the spark plug is reduced.

The invention relates to the technical field of liquid fuel engines, in particular to a valve injection structure integrated igniter which comprises a first valve shell, a second valve shell, a first hollow valve element assembly, a second hollow valve element assembly, a fluid driving assembly and a spark plug. When the second hollow valve element assembly moves upwards to jack up the first hollow valve element assembly, gas fuel enters the gas-oxygen channel, liquid fuel enters the kerosene channel, and the gas fuel and the liquid fuel are mixed at outlets of the kerosene channel and the gas-oxygen channel and then enter the fuel gas channel for ignition. Synchronous control over the first valve rod is achieved by controlling the second valve rod, so that propellant injection in the vapor-liquid dual-element propellant assembly is controlled at the same time, the response time of fuel injection is shortened, and reliable ignition is achieved.

The invention provides a two-component injector based on liquid oxygen and liquid methane and an attitude control engine. The injector at least comprises an injection disc, a spark plug, a liquid oxygen collecting cavity and a liquid methane collecting cavity. The injection disc is of a double-layer panel structure with a closed cavity, a plurality of connecting columns are arranged in the cavity, and the connecting columns are uniformly distributed and connected between the upper-layer panel and the lower-layer panel; at least part of the connecting columns are provided with injection holes penetrating through the upper-layer panel and the lower-layer panel. The liquid oxygen collecting cavity and the liquid methane collecting cavity are arranged on the outer end face of the upper-layer panel and are respectively communicated with the spray pipe through injection holes formed in the connecting columns; cooling holes communicated with the liquid methane collecting cavity, the cavity and the spray pipe are formed in the upper-layer panel and the lower-layer panel. The liquid methane entering the double-layer panel structure is used for cooling the injector.

The spark plug electrode comprises a grounding electrode, a central electrode and a plurality of precious metal plate electrodes are arranged at the central position of the grounding electrode, the precious metal plate electrodes are arranged on the periphery of the central electrode in the circumferential direction, and gaps between the precious metal plate electrodes and the central electrode are communicated with each other. The distances between the precious metal plate electrodes and the central electrode are the same, the grounding electrode is provided with a plurality of round holes, and the spark plug electrode is long in service life and easy to manufacture.

The utility model relates to the technical field of spark plugs, in particular to a spark plug sleeve which comprises a round sleeve, a square sleeve and a square sleeve rod, the top of the round sleeve is connected with the square sleeve in a welded mode, the top of the square sleeve is connected with the square sleeve rod in a sleeved mode, and the top of the square sleeve rod is provided with a connecting assembly. An inner hexagonal groove is formed in the circular sleeve, a groove is formed in the position, located on the outer side of the inner hexagonal groove, in the circular sleeve, a clamping piece is rotationally connected into the groove, and the outer surface of the circular sleeve is in threaded connection with a tightening screw rod corresponding to the clamping piece through a reserved threaded hole; by additionally arranging the auxiliary caliber adjusting mechanism and utilizing overturning and extruding modes, the spark plug fixing device adapts to spark plugs of different sizes, the use flexibility is improved, meanwhile, the convenience of disassembly and assembly operation is improved, and therefore the use effect is improved.

This utility model relates to an assembly guide fixture suitable for press-fitting spark plug sleeves in G16 engines, belonging to the field of automotive engine production equipment. The guide fixture is placed flat on the engine. Two locating pins are installed on the upper plate of the guide fixture. The locating pins are inserted into the locating holes on the engine surface to connect the guide fixture to the engine. The double locating pins ensure the accuracy of the fixture's assembly position. Four guide sleeves respectively ensure the position and direction of the four cylinder spark plug sleeves during press-fitting. The guide sleeves are designed according to the shape of the piston sleeve and cylinder head. The guide sleeves can effectively ensure that there is a gap between the spark plug sleeve and the guide fixture. The inner diameter of the spark plug sleeve press-fitting guide fixture is designed according to the outer diameter of the sleeve and the size of the cylinder head. Its machining and positional dimension accuracy requirements are high. The position of the four guide sleeves is based on the position of the cylinder bore of the G16 engine. The guide sleeves and the upper plate are positioned by a stop. Its function is to ensure that the spark plug sleeve and the spark plug sleeve mounting hole on the cylinder head are always coaxial during the press-fitting process, ensuring accurate press-fitting position.

Fuel injector (119) for injecting fuel into a combustion chamber (104) of an internal combustion engine, comprising: a first injection port group (410) directed towards a piston (103); a second injection opening group (411) which, in comparison to the first injection opening group, is directed towards a spark plug (120), wherein an injection port partial circle radius (R1) at which the center of injection ports of the first injection port group (410) is located is larger than an injection port partial circle radius (R3) at which the center of injection ports of the second injection port group (411) is located; and a valve body (201) which is raised such that a maximum valve body stroke amount becomes a first stroke amount or a second stroke amount which is less than the first stroke amount, wherein in a case where the maximum valve body stroke amount of the valve body (201) becomes the first stroke amount, a sum of the flow path areas of all injection ports becomes a minimum cross-sectional area of ​​a flow path and in a case where the maximum valve body stroke amount of the valve body (201) becomes the second stroke amount, a flow path area of ​​a seat section becomes the minimum cross-sectional area of ​​the flow path.

To provide a spark plug capable of improving ignitability while reducing wasting of a chip.SOLUTION: A spark plug comprises: an insulator that is provided with a shaft hole extending along an axis line; a central electrode that is arranged in the shaft hole; a main fitting that is arranged on the outer periphery of the insulator; and a grounding electrode that is connected to the main fitting. At least one of the central electrode and the grounding electrode includes a base material, and a chip that is joined to the base material and that consists primarily of Ru. The chip includes a discharge surface that faces the other one of the central electrode and the grounding electrode. An arithmetic average roughness of the discharge surface is in the range of 0.4-4.8 μm.SELECTED DRAWING: Figure 1

Spark plug, showing: a central electrode (10); a ground electrode (13) having a facing section (13A) which is facing a front end section (11) of the center electrode (10) and forms a discharge gap (SG) between the facing section (13A) and the front end section (11) of the center electrode (10); a cylindrical insulator (20) which receives the central electrode (10) therein, wherein the front end section (11) of the central electrode (10) is exposed from a front end of the insulator (20); a cylindrical metal housing (40) that accommodates the insulator (20) therein; and a cover part (50) which covers the front end section (11) of the center electrode (10) and the facing section (13A) of the ground electrode (13) from a front end side of the spark plug to form a pre-chamber (63), wherein the cover part (50) is connected to a front end of the metal housing (40) and has an injection opening (61) which is a through-hole, where a metal housing volume A (specified in mm²) 3 ) of a section of the metal housing (40) on the front end side with respect to a rear end (65) of the pre-chamber (63) and a thermal conductivity B (specified in W / mK) of the metal housing (40) at a normal temperature satisfy the relationship (1): 3.6 < A / B < 98.0 where the metal housing volume A (specified in mm²) 3 ) and a pre-chamber volume C (specified in mm³) 3 ) the antechamber (63) fulfill the relationship (2): 0.18 < C / A < 1.20

The application belongs to the technical field of methanol engine and discloses a marine pure methanol engine ignition preheating device and a control method, which comprises a control unit, a mounting sleeve and a spark plug heating device, the mounting sleeve is mounted on an engine cylinder head, the mounting sleeve comprises a lower mounting sleeve and an upper extension sleeve; the control unit comprises a first temperature sensor and a methanol injector arranged in an engine cylinder body, an engine ECU, a spark plug preheating control unit, a flywheel signal fluted disc connected with an engine rotor, a flywheel position sensor arranged at the flywheel signal fluted disc and a second temperature sensor connected with the spark plug; the spark plug heating device comprises a spark plug fixedly connected with the lower mounting sleeve, an electromagnetic heating coil arranged in the lower mounting sleeve and a terminal post. The application strengthens the atomization effect of the methanol in the cylinder by the mode of heating the spark plug through the electromagnetic induction coil, and prevents the problem of the spark plug immersion and the failure to ignite.

The utility model relates to a rocket engine ignition device comprising a spark plug and an exciter and a liquid rocket engine. The rocket engine ignition device comprises a first shell, an exciter low-voltage output cable, a connecting mechanism and a sealing mechanism. The spark plug is installed on the first shell, and the two ends of the spark plug are located inside and outside the first shell respectively. One end of the spark plug located outside the first shell is located in a combustion chamber of the rocket engine; the high-voltage end of the exciter is located in the first shell, one end of the exciter low-voltage output cable is located in the first shell and electrically connected with the high-voltage end of the exciter, and the other end of the exciter low-voltage output cable is electrically connected with the low-voltage end of the exciter. The high-voltage end of the exciter is electrically connected with the spark plug; the first shell is filled with insulating glue so as to carry out glue sealing on parts in the first shell. According to the utility model, condensed water can be prevented from entering between the spark plug and the exciter, outward electric leakage of the spark plug and the exciter is avoided, and the possibility of damage to the spark plug and the exciter is reduced.

Provided is a spark plug capable of reducing the occurrence of pre-ignition. The spark plug includes: an insulator provided with a shaft hole extending along an axis from a front end side to a rear end side, and a stepped portion having an outer diameter decreasing from the rear end side to the front end side; a center electrode disposed in the shaft hole; and a cylindrical main metal fitting disposed on the outer periphery of the insulator and having an inner peripheral surface, the main metal fitting including: a threaded portion comprising a male thread; a seat part including a seat surface provided on the rear end side of the threaded part; and a locking part which is provided on the inner peripheral surface and locks the stepped part. The relationship V / (R2 * L) < = 0.0170 is satisfied, where V (mm3) is the volume of a space inside the inner peripheral surface of the locking portion and excluding the center electrode and the insulator, R (mm) is the outer diameter of the threaded portion, and L (mm) is the distance from the tip of the main fitting to the seating surface.