Pre-ignition prevention spark plug, system and control method

Abstract

The invention discloses an anti-preignition spark plug, system and control method, and relates to the technical field of engine spark plugs. The anti-preignition spark plug comprises a ceramic insulator, the ceramic insulator is fixedly sleeved with a metal shell, a residual waste gas cavity exists between the ceramic insulator near a spark plug anode and the metal shell, an air pipeline is arranged in the side wall of the metal shell, an air inlet hole of the air pipeline is formed in the outer side wall of the metal shell, and a gas outlet hole of the air pipeline is formed in the outer side wall of the metal shell. A gas outlet hole of the air pipeline is formed in the inner side wall of the metal shell and is communicated with the residual waste gas cavity; the system comprises the anti-preignition spark plug and further comprises a high-pressure gas supply device, a needle valve and a control unit. The control method is based on the anti-preignition system and comprises the steps that the working condition is recognized, and purging in different modes is carried out by adjusting opening, closing and the opening degree of the needle valve. High-pressure gas is used for purging, and residual gas in the gap can be effectively removed, so that the preignition risk is reduced, and the safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine spark plugs, and in particular to an anti-pre-ignition spark plug, a system and a control method. Background Art

[0002] In a spark plug, a metal shell surrounds an insulating ceramic body, creating a tiny gap near the center electrode. During engine operation, these gaps can easily trap hot residual gases, particularly in high-hydrogen environments. This can easily lead to pre-ignition, impacting engine performance and safety. Existing treatments, such as regular spark plug replacement and the use of cleaning additives, can alleviate this problem to some extent, but they are costly and fail to fundamentally resolve the problem of residual gas accumulation.

[0003] Spark plugs generate a significant amount of heat during operation. If the heat can't be dissipated promptly and effectively, the spark plug temperature will rise rapidly, leading to material aging and performance degradation. Excessive temperatures can also cause pre-ignition. While existing thermal management measures, such as adding heat sinks and optimizing heat dissipation structures, have improved thermal management efficiency to a certain extent, they still pose problems such as uneven heat dissipation and localized overheating.

[0004] CN114788105B provides a passive pre-chamber spark plug for use in a combustion chamber of a vehicle engine. The spark plug comprises an upper pre-chamber including at least one upper opening, the upper pre-chamber being connected to the combustion chamber via the at least one upper opening; and an upper air spark gap through which an air ignition spark can be formed. Furthermore, an intermediate electrode is disposed in the upper region of the upper pre-chamber. The bottom of the upper pre-chamber, opposite the upper pre-chamber, is formed as an insulator, and a conductive element or gap is continuously guided through the insulator from the upper pre-chamber to a lower region below the bottom. The lower region is formed as a second pre-chamber or is disposed directly in the combustion chamber. A ground electrode is disposed in the lower region such that a lower air spark gap is formed between the ground electrode and the conductive element or gap.

[0005] However, this prior art cannot solve the problem of residual gas in the spark plug gap and excessive temperature, which may cause premature combustion and even component damage. Summary of the Invention

[0006] The purpose of the present invention is to provide a spark plug, system and control method for preventing pre-ignition. By using high-pressure gas purging, residual gas in the gap can be effectively removed, thereby reducing the risk of pre-ignition and solving the problem of low safety caused by pre-ignition due to residual gas and excessive temperature in the spark plug gap.

[0007] The present invention provides the following solutions:

[0008] A spark plug for preventing pre-ignition includes a ceramic insulator, a spark plug anode is provided at the lower end of the ceramic insulator, a metal shell is fixedly sleeved on the outer side wall of the ceramic insulator, an annular residual exhaust gas cavity is provided between the ceramic insulator near the spark plug anode and the metal shell, an air pipeline is provided inside the side wall of the metal shell, an air inlet of the air pipeline is provided in the middle of the outer side wall of the metal shell, an air outlet of the air pipeline is provided at the lower part of the inner side wall of the metal shell and is connected to the residual exhaust gas cavity, and a spark plug cathode is provided at the lower end of the metal shell adjacent to the spark plug anode.

[0009] Furthermore, the air duct includes an air flow channel, which includes a vertical flow channel and an inclined flow channel. The upper end of the vertical flow channel is connected to the air inlet, the lower part of the vertical flow channel is connected to the upper end of the inclined flow channel, and the lower end of the inclined flow channel is connected to the air outlet.

[0010] The high-pressure gas enters the vertical flow channel from the air inlet, and then is ejected from the air outlet through the inclined flow channel, so that the waste gas in the residual waste gas cavity can be blown out from the bottom.

[0011] Furthermore, the air duct includes an air flow channel, the upper end of the vertical flow channel of the air flow channel is directly connected to the air inlet, and the lower end of the inclined flow channel of the air flow channel is connected to the air outlet, and the air outlet is arranged on the inner side wall of the metal shell at the top of the residual exhaust gas chamber.

[0012] The air pipeline includes an air flow channel. This spark plug is simple to manufacture, has low cost, and can achieve a certain effect of removing residual exhaust gas.

[0013] Furthermore, the air duct includes a plurality of air flow channels, which are evenly distributed circumferentially inside the side wall of the metal shell. The upper end of each air flow channel is commonly connected to an annular flow channel and is connected to the air inlet through the annular flow channel. The annular flow channel is an annular closed flow channel, and the annular flow channel is directly connected to the air inlet.

[0014] The annular flow channel is connected to multiple air flow channels, and the multiple air flow channels are evenly distributed along the circumference, so that high-pressure gas can flow into the residual exhaust gas cavity from multiple directions at the same time, making the residual exhaust gas cavity discharged faster and more thoroughly.

[0015] Furthermore, each of the air flow channels includes a vertical flow channel and three oblique flow channels, and the three oblique flow channels are respectively a top oblique flow channel connected to the top of the residual exhaust gas chamber, a middle oblique flow channel connected to the middle of the residual exhaust gas chamber, and a bottom oblique flow channel connected to the bottom end of the residual exhaust gas chamber. The three oblique flow channels are commonly connected to the corresponding vertical flow channels, and are respectively arranged at obtuse angles to the vertical flow channels.

[0016] After the high-pressure gas is diverted through the annular flow channel, a laminar-turbulent transition state flow is formed in the air flow channel: the top oblique flow channel generates a high-speed jet, which directly impacts the top of the exhaust gas chamber to form a vortex peeling effect; the middle oblique flow channel establishes an axial pressure gradient, accelerating the exhaust gas discharge through the Bernoulli effect; the bottom oblique flow channel constructs an air film cooling layer, which can reduce the surface temperature of the spark plug anode and cathode; therefore, this air pipe structure can quickly discharge residual exhaust gas while reducing the surface temperature of the spark plug electrode, thereby reducing the risk of pre-ignition.

[0017] A pre-ignition prevention system includes the above-mentioned pre-ignition prevention spark plug, and also includes a high-pressure gas supply device, a needle valve and a control unit; the high-pressure gas supply device, the needle valve and the pre-ignition prevention spark plug are connected in sequence through a pipeline, and the control unit is electrically connected to the needle valve.

[0018] Furthermore, the high-pressure gas supply device includes a high-pressure gas cylinder, which is connected to a pressure reducing valve through a pipeline, the rear end of the pressure reducing valve is connected to a flow meter through a pipeline, the rear end of the flow meter is connected to a needle valve through a pipeline, and the rear end of the needle valve is connected to the air inlet hole of the anti-pre-ignition spark plug through a pipeline.

[0019] The high-pressure gas cylinder is connected to a pressure reducing valve through a pipeline, which is used to reduce the pressure of the output gas to a pressure value suitable for purging. The rear end of the pressure reducing valve is connected to a flow meter through a pipeline for monitoring the gas flow; the rear end of the flow meter is connected to the needle valve pipeline, and the needle valve is used to control the opening and closing and the size of the airflow; the rear end of the needle valve is connected to the air inlet hole of the anti-pre-ignition spark plug through a pipeline; the control unit is electrically connected to the needle valve, which is used to control the opening and closing and opening degree of the needle valve, thereby controlling the high-pressure gas to enter the anti-pre-ignition spark plug.

[0020] Furthermore, the needle valve includes a valve body, a cavity is provided inside the valve body, and a moving iron core is accommodated in the cavity with a limit seal; the upper end wall of the valve body is provided with a through hole, and the moving iron core includes a valve pin, and the valve pin can be slidably sleeved in the through hole, and the upper end of the valve pin is provided with a nail cap, which can be stopped on the upper surface of the valve body; a piston plate is provided in the middle of the valve pin, and the outer wall of the piston plate is sealed and slidably contacted with the inner wall of the cavity; a spring is fixedly connected between the upper surface of the piston plate and the lower surface of the upper end wall of the valve body; a nail head is provided at the lower end of the valve pin, and the nail head The head is conical, and a high-pressure gas outlet is provided on the lower end wall of the valve body. The high-pressure gas outlet is connected to the air inlet of the anti-pre-ignition spark plug through a pipe, and the nail head of the valve nail can be opened and closed and sleeved in the high-pressure gas outlet; a high-pressure gas inlet is provided on the middle or lower side wall of the valve body, and the high-pressure gas inlet is connected to the high-pressure gas supply device through a pipe; a coil is fixedly connected to the upper surface of the valve body, and an axial hole is provided in the center of the coil, the nail cap is slidably sleeved in the axial hole, and a fixed iron core is fixedly sleeved on the top of the axial hole, and the coil is electrically connected to the control unit.

[0021] The control unit can control the size of the electromagnetic force by controlling the size of the electric coil current, thereby controlling the rising distance of the moving iron core, and thus controlling the opening of the needle valve; the greater the rising distance of the moving iron core, the greater the opening of the needle valve, the larger the gap between the nail head and the inner wall of the high-pressure gas outlet, and thus the greater the flow rate of the high-pressure gas, and vice versa.

[0022] A control method for an anti-pre-ignition system, based on the above-mentioned anti-pre-ignition system, comprises the following steps:

[0023] S1, identify the engine exhaust valve opening signal, control the needle valve to open, and start purging;

[0024] S2. Identify the working conditions and adjust the duration of the needle valve opening to adjust the purge time;

[0025] S3. Identify the working conditions, adjust the opening of the needle valve, and perform the corresponding purge mode.

[0026] Furthermore, the step S1 includes, when the control unit detects through the sensor that the exhaust valve lift is ≥0.5 mm, sending an opening instruction to the needle valve, the needle valve opens, and the purging starts;

[0027] The step S2 includes the control unit identifying the operating condition through a sensor and adjusting the duration of the needle valve opening according to the operating condition; under low-risk operating conditions, the adjustment range of the duration of the needle valve opening is 2 to 15 degrees CA; under high-risk operating conditions, the duration of the needle valve opening is increased by 20% compared to the low-risk operating condition;

[0028] The step S3 includes, under the working condition of cold start of the engine, the control unit controls the initial opening of the needle valve to 80% for purging, and after 2 seconds, the opening of the needle valve is reduced to 50% for purging;

[0029] Under high speed and high load conditions, the control unit adjusts the needle valve opening according to the exhaust valve lift percentage. The needle valve opening is adjusted by the following formula:

[0030] K=0.8×P+15%,

[0031]

[0032] Where K is the opening of the needle valve, P is the exhaust valve lift percentage, S1 is the current exhaust valve lift, and S is the maximum exhaust valve lift;

[0033] In the pre-ignition warning state, the control unit sends a pulse signal to control the needle valve to generate a pulse airflow for purging.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The present invention provides a spark plug, system and control method for preventing pre-ignition. The system utilizes high-pressure gas purging to effectively remove residual gas in the gap, and can perform purging in different modes and intensities according to different working conditions, thereby reducing the risk of pre-ignition, saving energy consumption, and extending the life of the spark plug and the engine. The system solves the problem of low safety caused by pre-ignition due to residual gas and excessive temperature in the spark plug gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Attachment Figure 1 This is a schematic structural diagram of the anti-pre-ignition spark plug according to Example 1 of the present invention;

[0038] Attachment Figure 2 This is a schematic structural diagram of the anti-pre-ignition spark plug according to embodiment 2 of the present invention;

[0039] Attachment Figure 3 Schematic top view of the cross-section of the spark plug for preventing pre-ignition according to embodiment 2 of the present invention;

[0040] Attachment Figure 4 This is a schematic structural diagram of the anti-pre-ignition spark plug according to embodiment 3 of the present invention;

[0041] Attachment Figure 5 This is a schematic structural diagram of the anti-pre-ignition system of the present invention;

[0042] Attachment Figure 6 This is a schematic structural diagram of the needle valve of the anti-pre-ignition system of the present invention;

[0043] Attachment Figure 7 Schematic diagram of the control method of the anti-pre-ignition system of the present invention.

[0044] In the picture:

[0045] 1-anti-pre-ignition spark plug, 11-ceramic insulator, 111-spark plug anode, 12-metal shell, 121-spark plug cathode, 13-air pipe, 131-air flow channel, 1311-vertical flow channel, 1312-oblique flow channel, 13121-top oblique flow channel, 13122-middle oblique flow channel, 13123-bottom oblique flow channel, 132-air inlet, 133-air outlet, 134-annular flow channel, 14-residual exhaust gas chamber, 2-high-pressure gas supply device, 21-high-pressure gas cylinder, 22-pressure reducing valve, 23-flow meter, 3-needle valve, 31-valve body, 311-high-pressure gas outlet, 312-high-pressure gas inlet, 32-moving iron core, 321-valve pin, 3211-pin cap, 3212-pin head, 322-piston plate, 33-coil, 331-shaft hole, 34-fixed iron core, 35-spring, 4-control unit. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of this application more clear, this application will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0047] The terms used in the examples of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a," "the," and "the" used in the examples of this application and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0048] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0049] It should be understood that although the terms first, second, third, etc. may be used to describe in the embodiments of the present application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, without departing from the scope of the embodiments of the present application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0050] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0051] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0052] It should be noted in particular that any symbols and / or numbers in the specification that are not marked in the accompanying drawings are not drawing marks.

[0053] Example 1, please refer to Figure 1 As shown, this embodiment provides an anti-pre-ignition spark plug 1, including a ceramic insulator 11, a spark plug anode 111 is provided at the lower end of the ceramic insulator 11, a metal shell 12 is fixedly sleeved on the outside of the ceramic insulator 11, a residual exhaust gas chamber 14 is formed between the ceramic insulator 11 and the metal shell 12 near the spark plug anode 111, an air pipe 13 is provided inside the side wall of the metal shell 12, an air inlet 132 of the air pipe 13 is provided on the outer wall of the metal shell 12, an air outlet 133 of the air pipe 13 is provided on the inner wall of the metal shell 12 and is connected to the residual exhaust gas chamber 14, and a spark plug cathode 121 is also provided at the lower end of the metal shell 12.

[0054] Specifically, in this embodiment, the air pipe 13 includes an air flow channel 131, and the air flow channel 131 includes a vertical flow channel 1311 and an oblique flow channel 1312. The upper end of the vertical flow channel 1311 is connected to the air inlet 132, the lower end of the vertical flow channel 1311 is connected to the upper end of the oblique flow channel 1312, and the lower end of the oblique flow channel 1312 is connected to the air outlet 133. The air outlet 133 is arranged on the inner side wall of the metal shell 12 at the top of the residual exhaust gas chamber 14; the high-pressure gas enters the vertical flow channel 1311 from the air inlet 132, and then is ejected from the air outlet 133 through the oblique flow channel 1312, so that the exhaust gas in the residual exhaust gas chamber 14 can be blown out from the bottom.

[0055] See also Figure 5As shown, this embodiment also provides an anti-pre-ignition system, including the above-mentioned anti-pre-ignition spark plug 1, and also includes a high-pressure gas supply device 2, a needle valve 3 and a control unit 4.

[0056] Specifically, the high-pressure gas supply device 2 includes a high-pressure gas cylinder 21, which is connected to a pressure reducing valve 22 through a pipeline, which is used to reduce the pressure of the output gas to a pressure value suitable for purging. The rear end of the pressure reducing valve 22 is connected to a flow meter 23 through a pipeline, which is used to monitor the gas flow; the rear end of the flow meter 23 is connected to the needle valve 3 pipeline, and the needle valve 3 is used to control the opening and closing and the size of the airflow; the rear end of the needle valve 3 is connected to the air inlet 132 of the anti-pre-ignition spark plug 1 through a pipeline; the control unit 4 is electrically connected to the needle valve 3, which is used to control the opening and closing and the opening degree of the needle valve 3, thereby controlling the high-pressure gas to enter the anti-pre-ignition spark plug 1; the control unit 4 adopts an ECU, that is, an electronic control unit 4, also known as a "driving computer" or "on-board computer", which is a car-specific microcomputer controller, also called a car-specific single-chip microcomputer. It receives sensor signals, processes and makes decisions, and then sends control signals to the actuator to achieve precise control of various systems of the car.

[0057] See also Figure 6 As shown, specifically, the needle valve 3 includes a valve body 31, the interior of the valve body 31 is provided with a cavity, and the cavity contains a movable iron core 32 with a limit seal, and the upper end wall of the valve body 31 is provided with a through hole, and the movable iron core 32 can be slidably sleeved in the through hole, and the top end of the movable iron core 32 can be stopped on the upper surface of the valve body 31; a coil 33 is fixedly connected to the upper surface of the valve body 31, and an axial hole 331 is provided in the center of the coil 33, and the top end of the movable iron core 32 is slidably sleeved in the axial hole 331, and a fixed iron core 34 is fixedly sleeved on the top end of the axial hole 331, and the coil 33 is electrically connected to the control unit 4.

[0058] The movable iron core 32 includes a valve pin 321, the upper end of the valve pin 321 is a pin cap 3211, the pin cap 3211 can be stopped on the upper surface of the valve body 31, the lower end of the valve pin 321 is a pin head 3212, the pin head 3212 is conical, and a piston plate 322 is provided in the middle of the valve pin 321, the outer wall of the piston plate 322 is in sealing and slidable contact with the inner wall of the cavity; a spring 35 is fixedly connected between the upper surface of the piston plate 322 and the lower surface of the upper end wall of the valve body 31; a high-pressure gas outlet 311 is provided on the lower end wall of the valve body 31, which is connected to the air inlet 132 of the anti-pre-ignition spark plug 1 through a pipeline, and the pin head 3212 of the valve pin 321 can be sealed or gap-fitted into the high-pressure gas outlet 311; a high-pressure gas inlet 312 is provided on the middle or lower side wall of the valve body 31, which is connected to the high-pressure gas supply device 2 through a pipeline.

[0059] When the coil 33 is not energized, the nail cap 3211 stops on the upper surface of the valve body 31, the nail head 3212 of the valve nail 321 is sealed and sleeved in the high-pressure gas outlet 311, and the needle valve 3 is in a closed state; when the coil 33 is energized, an electromagnetic force is generated, which is amplified by the fixed iron core 34 and the movable iron core 32. The movable iron core 32 slides upward under the action of the electromagnetic force, and the spring 35 is compressed. A gap is generated between the nail head 3212 of the valve nail 321 and the inner wall of the high-pressure gas outlet 311, and the needle valve 3 is opened, and the high-pressure gas can flow out of the valve body 31 through the gap; the control unit 4 can control the magnitude of the electromagnetic force by controlling the magnitude of the coil current, thereby controlling the rising distance of the movable iron core 32, and thus controlling the opening of the needle valve 3; the greater the rising distance of the movable iron core 32, the greater the opening of the needle valve 3, the larger the gap between the nail head 3212 and the inner wall of the high-pressure gas outlet 311, and thus the greater the flow rate of the high-pressure gas, and vice versa.

[0060] Example 2, please refer to Figure 2 and Figure 3 As shown, this embodiment provides an anti-pre-ignition spark plug 1, which improves the structure of the air pipe 13 on the basis of embodiment 1.

[0061] Specifically, the air pipeline 13 includes multiple air flow channels 131. This embodiment preferably includes four air flow channels 131. The upper ends of the four air flow channels 131 are commonly connected to an annular flow channel 134. The annular flow channel 134 is an annular closed flow channel. The annular flow channel 134 is connected to the air inlet 132. The four air flow channels 131 are evenly distributed along the circumference, so that high-pressure gas can flow into the residual exhaust gas chamber 14 from four directions at the same time, so that the residual exhaust gas chamber 14 can be discharged faster and more thoroughly.

[0062] This embodiment further provides an anti-pre-ignition system, which includes the anti-pre-ignition spark plug 1 of embodiment 2 on the basis of embodiment 1 and has all the advantages of the anti-pre-ignition spark plug 1 .

[0063] Example 3, please refer to Figure 4 As shown, this embodiment provides an anti-pre-ignition spark plug 1, which improves the structure of the air flow channel 131 on the basis of embodiment 2.

[0064] Specifically, each air flow channel 131 includes a vertical flow channel 1311 and three oblique flow channels 1312. The three oblique flow channels 1312 are connected to the vertical flow channel 1311. The three oblique flow channels 1312 are respectively a top oblique flow channel 13121, a middle oblique flow channel 13122 and a bottom oblique flow channel 13123, which are respectively connected to the top, middle and bottom ends of the residual exhaust chamber 14. The three oblique flow channels 1312 are respectively connected to the vertical flow channel 1311 above each other. The obtuse angle of the flow channel 1311 can reduce the loss of impact force of the high-pressure airflow; the angle between the top oblique flow channel 13121 and the vertical flow channel 1311 and the angle between the middle oblique flow channel 13122 and the vertical flow channel 1311 are 120° to 150°, and the angle between the bottom oblique flow channel 13123 and the vertical flow channel 1311 is determined according to the positions of the spark plug anode 111 and the spark plug cathode 121, so as to blow as directly onto the surfaces of the two as possible.

[0065] After being diverted through annular flow channel 134, high-pressure gas (preferably at 0.5-1.2 MPa) forms a laminar-turbulent transitional flow within air channel 131: Top oblique flow channel 13121 generates a high-speed jet at ≥80 m / s, directly impacting the top of the exhaust chamber to create a vortex shedding effect; middle oblique flow channel 13122 establishes an axial pressure gradient, accelerating exhaust gas discharge through the Bernoulli effect; and bottom oblique flow channel 13123 forms an air film cooling layer with a thickness of approximately 0.2-0.5 mm, which can reduce the surface temperature of the spark plug anode 111 and cathode by 80-120°C. Therefore, this air duct 13 structure can quickly discharge residual exhaust gas while simultaneously lowering the spark plug electrode surface temperature, thereby reducing the risk of pre-ignition.

[0066] This embodiment further provides an anti-pre-ignition system, which includes the anti-pre-ignition spark plug 1 of embodiment 3 on the basis of embodiment 1 and has all the advantages of the anti-pre-ignition spark plug 1 .

[0067] See also Figure 7 As shown, this embodiment further provides a control method for an anti-pre-ignition system, based on the above-mentioned anti-pre-ignition system.

[0068] Specifically, because the opening of the engine's exhaust valve is linked to crankshaft position and camshaft phase, the ECU receives real-time signals from the crankshaft position sensor and camshaft phase sensor, accurately determining the timing of exhaust valve opening and simultaneously triggering the opening command for needle valve 3. Needle valve 3's response time is ≤ 2ms, ensuring that high-pressure gas injection coincides with the peak of the exhaust valve lift curve during the exhaust phase, maximizing exhaust purge efficiency.

[0069] Specifically, when the ECU detects that the exhaust valve lift is ≥0.5mm, it sends a PWM modulation signal (duty cycle adjustable from 30% to 100%) to needle valve 3. After the high-pressure gas is evenly distributed through the annular cavity, the pressure difference between each flow channel is controlled within ±5%, ensuring flow consistency across the four flow channels.

[0070] The top oblique flow channel 13121 jet covers 90% of the top area of the exhaust gas chamber, with a residence time of ≤5ms; the middle oblique flow channel 13122 establishes a guiding airflow with an axial flow velocity of ≥15m / s; the bottom oblique flow channel 13123 forms an annular cooling air curtain, improving heat exchange efficiency;

[0071] Based on the feedback data from the cylinder pressure sensor, the ECU dynamically adjusts the duration of needle valve 3's opening. In low-risk conditions, the adjustment range is 2 to 15°CA. In high-risk conditions, the purge time is increased by 20%. The duration of needle valve 3's opening is the time period from when needle valve 3 is fully open to when it is fully closed, corresponding to the angular range of the engine crankshaft's rotation. For example, 15°CA means that needle valve 3 remains open during a period of 15 degrees of crankshaft rotation. The adjustment range of 2 to 15°CA indicates that this parameter can be adjusted according to actual operating conditions, and can be shortened to a minimum of 2°CA (extremely short opening time) and extended to a maximum of 15°CA (longer opening time).

[0072] Low-risk operating conditions refer to conditions where the engine speed is greater than 2500 rpm, or the torque output is low, such as light load, flat ground, and constant speed driving;

[0073] High-risk operating conditions refer to conditions where a turbocharged direct injection engine operates at high torque at low speeds (1000-2500 rpm), such as when driving with high loads, climbing slopes, or accelerating or decelerating at high acceleration rates.

[0074] In the opening control of the needle valve 3, the following technical means are usually used to achieve precise flow regulation: the coil 33 receives the drive signal (PWM or analog voltage) output by the ECU, generating an electromagnetic force that is positively correlated with the current intensity; the moving iron core 32 generates axial displacement under the dynamic balance between the electromagnetic force and the force of the spring 35, and the displacement range is adjustable from 0.1 to 3 mm; the displacement of the moving iron core 32 is nonlinearly related to the gas flow cross-sectional area, and a displacement-flow characteristic curve needs to be established through calibration; a 5-20kHz frequency is used. Driven by a PWM signal, the average current of the coil 33 is adjusted within a duty cycle range of 10%-90%, with an average current of 0.1 to 1.2A. For the nonlinear section of the needle valve 3 flow characteristic, i.e., the stage where the opening is less than 30%, a pre-stored MAP diagram is used for duty cycle-flow calibration. During the process from full closure to full opening of the valve core, an overdrive pulse of 120% of the rated current in the initial stage is applied (lasting 5ms), shortening the response time to ≤3ms. An integrated Hall sensor monitors the position of the moving iron core 32 in real time (accuracy of ±0.05mm). Through the feedback signal of the gas mass flowmeter 23 (sampling rate of 1kHz), the ECU uses a PID algorithm to dynamically adjust the PWM duty cycle, with a steady-state flow error of less than ±2%, thereby achieving precise regulation of the high-pressure gas flow.

[0075] In this embodiment, different purge modes are set for different working conditions:

[0076] When the engine is cold-started, the control unit 4 controls the needle valve 3 to initially open at 80% for rapid purging, and then reduces the opening to 50% after 2 seconds. Because the residual exhaust gas chamber 14 often contains the largest amount of residual exhaust gas before the engine is cold-started, rapid purging is required, and the opening is reduced to a normal level after 2 seconds, thereby satisfying the purging requirement and saving energy.

[0077] Under high speed and high load conditions, the opening of needle valve 3 is proportionally adjusted synchronously with the exhaust valve lift, that is, K = 0.8 × P + 15%.

[0078] Where K is the opening of needle valve 3, P is the exhaust valve lift percentage, S1 is the current exhaust valve lift, and S is the maximum exhaust valve lift;

[0079] As the engine load increases, the risk of pre-ignition also increases. The higher the engine load, the greater the exhaust valve lift. Therefore, the opening of the needle valve 3 also increases with the increase in the exhaust valve lift.

[0080] When the risk of pre-ignition rises to the pre-ignition warning state: the control unit 4 uses 50Hz square wave modulation control to generate pulsed airflow, and uses airflow pulsation to enhance local disturbances, making it easier to discharge exhaust gas, with an amplitude of ±5%; the pre-ignition warning state needs to be determined according to different vehicles and different engine models. In this embodiment, the situation where the exhaust valve lift percentage is ≥80% is set as the pre-ignition warning state.

[0081] By performing purging in different modes and intensities according to different working conditions, the risk of pre-ignition can be greatly reduced, energy consumption can be saved, and the life of the spark plug and engine can be extended.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A spark plug for preventing pre-ignition, characterized in that: The invention comprises a ceramic insulator (11), wherein a spark plug anode (111) is provided at the lower end of the ceramic insulator (11), a metal shell (12) is fixedly sleeved on the outer side wall of the ceramic insulator (11), an annular residual exhaust gas chamber (14) is provided between the ceramic insulator (11) near the spark plug anode (111) and the metal shell (12), an air pipe (13) is provided inside the side wall of the metal shell (12), an air inlet (132) of the air pipe (13) is provided at the middle of the outer side wall of the metal shell (12), an air outlet (133) of the air pipe (13) is provided at the lower part of the inner side wall of the metal shell (12) and is connected to the residual exhaust gas chamber (14), and a spark plug cathode (121) is provided at the lower end of the metal shell (12) and is adjacent to the spark plug anode (111).

2. The spark plug for preventing pre-ignition according to claim 1, wherein: The air pipeline (13) comprises an air flow channel (131), and the air flow channel (131) comprises a vertical flow channel (1311) and an oblique flow channel (1312). The upper end of the vertical flow channel (1311) is connected to the air inlet (132), the lower part of the vertical flow channel (1311) is connected to the upper end of the oblique flow channel (1312), and the lower end of the oblique flow channel (1312) is connected to the air outlet (133).

3. The spark plug for preventing pre-ignition according to claim 2, wherein: The air pipeline (13) includes an air flow channel (131), the upper end of the vertical flow channel (1311) of the air flow channel (131) is directly connected to the air inlet (132), and the lower end of the inclined flow channel (1312) of the air flow channel (131) is connected to the air outlet (133), and the air outlet (133) is provided on the inner side wall of the metal shell (12) at the top of the residual exhaust chamber (14).

4. The spark plug for preventing pre-ignition according to claim 2, wherein: The air pipeline (13) includes a plurality of air flow channels (131), which are evenly distributed along the circumferential direction inside the side wall of the metal shell (12). The upper end of each air flow channel (131) is commonly connected to an annular flow channel (134) and is connected to the air inlet (132) through the annular flow channel (134). The annular flow channel (134) is an annular closed flow channel, and the annular flow channel (134) is directly connected to the air inlet (132).

5. The spark plug for preventing pre-ignition according to claim 4, characterized in that: Each of the air flow channels (131) comprises a vertical flow channel (1311) and three oblique flow channels (1312). The three oblique flow channels (1312) are respectively a top oblique flow channel (13121) connected to the top of the residual exhaust gas chamber (14), a middle oblique flow channel (13122) connected to the middle of the residual exhaust gas chamber (14), and a bottom oblique flow channel (13123) connected to the bottom of the residual exhaust gas chamber (14). The three oblique flow channels (1312) are commonly connected to the corresponding vertical flow channel (1311) and are respectively arranged at an obtuse angle to the vertical flow channel (1311).

6. A system for preventing premature ignition, characterized in that: The invention comprises an anti-pre-ignition spark plug (1) as claimed in any one of claims 1 to 5, and further comprises a high-pressure gas supply device (2), a needle valve (3) and a control unit (4); the high-pressure gas supply device (2), the needle valve (3) and the anti-pre-ignition spark plug (1) are connected in sequence through a pipeline, and the control unit (4) is electrically connected to the needle valve (3).

7. The anti-pre-ignition system according to claim 6, characterized in that: The high-pressure gas supply device (2) comprises a high-pressure gas cylinder (21), the high-pressure gas cylinder (21) is connected to a pressure reducing valve (22) via a pipeline, the rear end of the pressure reducing valve (22) is connected to a flow meter (23) via a pipeline, the rear end of the flow meter (23) is connected to a needle valve (3) via a pipeline, and the rear end of the needle valve (3) is connected to an air inlet (132) of an anti-pre-ignition spark plug (1) via a pipeline.

8. The anti-pre-ignition system according to claim 6, characterized in that: The needle valve (3) includes a valve body (31), the interior of the valve body (31) is provided with a cavity, and a movable iron core (32) is accommodated in the cavity in a limited seal; the upper end wall of the valve body (31) is provided with a through hole, and the movable iron core (32) includes a valve pin (321), and the valve pin (321) can be slidably sleeved in the through hole, and the upper end of the valve pin (321) is provided with a nail cap (3211), and the nail cap (3211) can be stopped on the upper surface of the valve body (31); a piston plate (322) is provided in the middle of the valve pin (321), and the outer wall of the piston plate (322) is sealed and slidably contacted with the inner wall of the cavity; a spring (35) is fixedly connected between the upper surface of the piston plate (322) and the lower surface of the upper end wall of the valve body (31); a nail head (3212) is provided at the lower end of the valve pin (321), and the nail head (3212) is The valve body (31) is conical in shape, and a high-pressure gas outlet (311) is provided on the lower end wall of the valve body (31), and the high-pressure gas outlet (311) is communicated with the air inlet (132) of the anti-pre-ignition spark plug (1) through a pipeline, and the nail head (3212) of the valve nail (321) can be opened and closed and sleeved in the high-pressure gas outlet (311); a high-pressure gas inlet (312) is provided on the middle or lower side wall of the valve body (31), and the high-pressure gas inlet (312) is communicated with the high-pressure gas supply device (2) through a pipeline; a coil (33) is fixedly connected to the upper surface of the valve body (31), and an axial hole (331) is provided at the center of the coil (33), and the nail cap (3211) is slidably sleeved in the axial hole (331), and a fixed iron core (34) is fixedly sleeved on the top of the axial hole (331), and the coil (33) is electrically connected to the control unit (4).

9. A control method for preventing pre-ignition system, characterized in that: The anti-pre-ignition system according to claim 6 comprises the following steps: S1, identifying the engine exhaust valve opening signal, controlling the needle valve (3) to open and start purging; S2, identifying the working condition, adjusting the duration of the needle valve (3) opening, and thus adjusting the purge duration; S3. Identify the working condition, adjust the opening of the needle valve (3), and perform the corresponding purge mode.

10. The control method of the anti-pre-ignition system according to claim 9, characterized in that: The step S1 includes: when the control unit (4) detects that the exhaust valve lift is ≥0.5 mm through a sensor, sending an opening instruction to the needle valve (3), and the needle valve (3) opens to start purging; The step S2 includes: the control unit (4) identifies the working condition through a sensor and adjusts the duration of the needle valve (3) being open according to the working condition; under low-risk working conditions, the adjustment range of the duration of the needle valve (3) being open is 2 to 15°CA; under high-risk working conditions, the duration of the needle valve (3) being open is increased by 20% compared to the low-risk working condition; The step S3 comprises: under the condition of cold start of the engine, the control unit (4) controls the needle valve (3) to initially open 80% for purging, and after 2 seconds, the needle valve (3) is opened to 50% for purging; Under high speed and high load conditions, the control unit (4) adjusts the opening of the needle valve (3) according to the exhaust valve lift percentage. The opening of the needle valve (3) is adjusted by the following formula: K=0.8×P+15%, Where K is the opening of the needle valve (3), P is the exhaust valve lift percentage, S1 is the current exhaust valve lift, and S is the maximum exhaust valve lift; In the pre-ignition warning state, the control unit (4) sends a pulse signal to control the needle valve (3) to generate a pulse airflow for purging.

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