Internal combustion engine ignition control system and control method

Abstract

The internal combustion engine ignition control system comprises at least one ignition control module, the ignition control module is provided with a signal input end used for receiving an ignition signal of an engine electronic control unit, and the ignition control module further comprises an output end used for being in gap coupling connection with a spark plug to provide ignition energy. The ignition control module provides and controls ignition energy in real time within an ignition duration according to dynamic requirements in an engine cylinder. And the magnitude and the lasting period of the discharge current can be effectively controlled as required by detecting the impedance in the plasma channel. The invention has wide application scenarios, including high-speed vehicle engines, low-speed marine engines, fixed internal combustion engine power generation systems and gas turbine systems. The ignition system has the self-adaptive ignition logic, and the needed ignition energy can be automatically judged according to different application scenes.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine ignition control, specifically to an internal combustion engine ignition control system and control method. Background Technology

[0002] To further improve the efficiency of spark-ignition engines, intake dilution and in-cylinder strong flow technologies have been widely adopted. However, under these operating conditions, stable ignition of the combustible mixture is particularly important for maintaining stable engine operation. Increasing the ignition duration and increasing the ignition current intensity are considered effective methods to achieve a lean mixture. However, high discharge current levels and long discharge durations lead to increased power consumption in the ignition system, and more importantly, accelerate the electro-corrosion of the spark plug electrodes, resulting in reduced spark plug electrode durability. Therefore, there is an urgent need for hardware and control strategies that can flexibly adjust ignition energy according to different engine operating conditions to dynamically optimize ignition energy.

[0003] During engine ignition, the elongated plasma channel due to in-cylinder flow increases the ignition volume, which is beneficial for generating a more stable initial spark. However, the elongation of the plasma can also lead to interruption or blow-out of the ignition channel, causing the initial spark to disperse and resulting in misfire. Adjusting the impedance of the ignition plasma channel in a timely manner can effectively reduce the probability of the plasma channel being interrupted.

[0004] The impedance of a plasma channel is primarily determined by the plasma length, background density, temperature, and discharge current. Variations in the discharge current control the degree of ionization within the plasma channel and are the most effective method for controlling plasma impedance. Rapid, adaptive adjustment of the discharge current at the microsecond level effectively ensures continuous plasma discharge for 2-3 milliseconds during ignition, thereby guaranteeing optimal ignition performance.

[0005] Currently, many publicly available ignition systems possess the function of extending ignition duration. Among them, the most influential is the dual-coil staggered ignition system. Different companies and research groups have applied for numerous patents regarding the structure, setup, and control methods of dual-coil systems, mainly to optimize the working process of dual-coil ignition systems, such as controlling the discharge current intensity and real-time detection of plasma interruption. For example, the US patent publication "US20120160222A1" entitled "DUAL COILIGNITION" discloses an improved automotive dual-cycle ignition system. However, due to the lack of fast hardware control and control logic, this patent cannot achieve the real-time provision of appropriate ignition energy and power according to engine needs. Another example is the Chinese patent publication "CN113217249A" entitled "Ignition Control System, Engine, Ignition Control Method, and Storage Medium." This discloses an ignition control system, engine, ignition control method, and storage medium. The ignition control system includes a logic calculation drive control module, a constant current power output module, an ignition coil drive module, an ignition coil module, and an energy storage capacitor. The logic calculation-driven control module can receive ignition control commands and acquire ignition control parameter information, including ignition charging parameter information and ignition discharge parameter information. In published patents, if plasma is found to be interrupted, the ignition coil can only be re-driven for ignition, but this will cause a shift in the combustion phase, leading to an increase in hydrocarbon emissions. It is impossible to prolong the discharge duration by preventing plasma interruption. The discharge current of the dual-coil ignition strategy used in the published patents is low, and it is impossible to prevent plasma interruption by increasing the discharge current. Therefore, proposing a fast-responding and on-demand control method for internal combustion engines is of great significance in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an internal combustion engine ignition control system, including at least one ignition control module. The ignition control module has a signal input terminal for receiving ignition signals from the engine electronic control unit, and a high-voltage output terminal for coupling with the spark plug gap to provide ignition energy. The ignition control module provides and controls ignition energy in real time according to the dynamic demand in the engine cylinder during the ignition duration.

[0007] Furthermore, the ignition control module includes a main control unit, at least one ignition energy control unit, and at least one dedicated ignition coil. The output terminals of the dedicated ignition coil and the ignition energy control unit are connected in parallel and then coupled to the spark plug gap. The main control unit receives the in-cylinder plasma feedback signal provided by the dedicated ignition coil. The main control unit also receives the combustion feedback signal provided by the dedicated ignition coil and the ignition energy control unit. The main control unit outputs control signals to the ignition energy control unit and the dedicated ignition coil according to the dynamic requirements of the engine cylinder to provide and control ignition energy in real time.

[0008] Furthermore, the ignition control module includes a main control unit, an ignition energy control unit, and multiple dedicated ignition coils. The number of dedicated ignition coils corresponds to the number of spark plugs. The output terminal of a single dedicated ignition coil is coupled to the gap of a single spark plug. The output terminal of the ignition energy control module is coupled to the gap of each spark plug.

[0009] Furthermore, the dedicated ignition coil includes a primary coil and a secondary coil. The primary coil is connected to a switching element to receive an ignition signal, and the secondary coil has an output terminal coupled to the spark plug gap. The high-voltage output terminal of the ignition energy control unit is coupled to the spark plug gap.

[0010] Furthermore, a unidirectional circuit two is connected between the high-voltage output terminal of the ignition energy control unit and the output terminal of the secondary coil.

[0011] Furthermore, the dedicated ignition coil includes a discharge voltage monitoring circuit for acquiring in-cylinder plasma voltage signals and providing them to the main control unit.

[0012] Furthermore, the turns ratio of the secondary coil to the primary coil is between 70:1 and 120:1, resulting in a high boost ratio and a low output current.

[0013] Furthermore, the ignition energy control unit includes multiple auxiliary ignition coils arranged in parallel, each auxiliary ignition coil being connected to a high-voltage diode and then coupled to the spark plug gap.

[0014] Furthermore, the turns ratio of the auxiliary ignition coil is between 25:1 and 40:1, which has a low boost ratio and a high output current.

[0015] Furthermore, the ignition energy control unit includes a DC boost transformer, an energy storage capacitor, and a field-effect diode. One side of the DC boost transformer is connected to the power supply, and the other side is connected to the energy storage capacitor. It is then connected to the high-voltage output terminal through the field-effect diode and finally connected to the high-voltage input terminal of the secondary coil of the dedicated ignition coil.

[0016] A method for controlling the ignition of an internal combustion engine is also proposed, characterized by employing the aforementioned ignition control system and specifically including the following steps: S1, the initial ignition stage, after the dedicated ignition coil receives the ignition command, its secondary coil provides high voltage to achieve breakdown and establish a plasma channel in the spark gap. S2, continuous ignition stage: After the plasma channel is established, a continuous ignition current is provided for the spark gap. S3. During the continuous ignition phase, the impedance change of the plasma channel in the internal combustion engine cylinder is acquired, and the continuous ignition current is adjusted in real time according to the impedance change to ensure that the plasma is not interrupted by the airflow in the cylinder during the target discharge duration.

[0017] Furthermore, in step S3, the discharge voltage of the plasma in the plasma channel is obtained to obtain the change in plasma channel impedance; when the discharge voltage of the plasma exceeds a certain preset threshold, the ignition current amplitude level of the spark gap is increased by the ignition energy control unit.

[0018] Furthermore, in step S3, the flow rate of the plasma channel is determined before the impedance change. If the plasma channel has a low flow rate, a first control strategy is adopted for the continuous ignition current; if the plasma channel has a high flow rate, a second control strategy is adopted for the continuous ignition current.

[0019] Furthermore, in the first control strategy, the continuous ignition current adopts a first power output and has a first discharge duration.

[0020] Furthermore, in the second control strategy, the re-breakdown probability of the plasma channel is predicted. If the re-breakdown probability is high, the continuous ignition current amplitude level is increased.

[0021] Furthermore, in the second control strategy, the discharge voltage change rate and amplitude of the continuous ignition current are obtained to predict the possibility of plasma channel re-breakdown.

[0022] Furthermore, in the second control strategy, the plasma channel flow rate is determined by the rate of change of the discharge voltage of the continuous ignition current.

[0023] Furthermore, the second control strategy also includes combustion diagnosis. If there is a high probability of re-breakdown and the combustion diagnosis is normal, the continuous ignition current amplitude level is increased; if there is a high probability of re-breakdown but the combustion diagnosis shows partial combustion, the continuous ignition current amplitude level is increased and the discharge duration is increased; if there is a low probability of re-breakdown but the combustion diagnosis shows partial combustion, the discharge duration of the continuous ignition current is increased.

[0024] Furthermore, the combustion diagnosis involves providing a pulsed current signal through the ignition energy control unit after the initial ignition phase, attempting to release a pulsed ignition current at a stimulation voltage lower than the re-breakdown voltage threshold during the spark gap, and monitoring the discharge voltage or discharge current signal at this time. If the actual ignition current signal cannot be obtained, it is diagnosed as partial combustion; otherwise, it is diagnosed as normal combustion.

[0025] Alternatively, the combustion diagnosis can be performed after the initial ignition phase, based on plasma impedance to determine whether combustion is normal.

[0026] Furthermore, the combustion diagnosis is based on the rate of change of discharge voltage under the current continuous discharge current obtained after the initial ignition stage. If the rate of change is lower than the rate of change of discharge voltage of plasma in an air environment, the combustion is diagnosed as normal; otherwise, it is diagnosed as partial combustion.

[0027] Compared with existing technologies, the technical solution of this application has the following beneficial effects: The internal combustion engine ignition control method proposed in this invention utilizes control hardware including a dedicated ignition coil, an ignition energy control unit, and a main control unit, which can achieve high-speed response of ignition current output. Furthermore, it can effectively control the magnitude and duration of the discharge current as needed by detecting the impedance in the plasma channel. This invention has a wide range of applications, including high-speed automotive engines, low-speed marine engines, stationary internal combustion engine power generation systems, and gas turbine systems. This ignition system has adaptive intelligent ignition logic, which can automatically determine the required ignition energy according to different application scenarios. Attached Figure Description

[0028] Figure 1 Schematic diagram of the ignition control system; Figure 2 Ignition control system principle Figure 1 ; Figure 3 Ignition control system principle Figure 2 ; Figure 4 Ignition control system principle Figure 3 ; Figure 5 : Ignition control waveform diagram of a four-cylinder engine; Figure 6 : Schematic diagram of the dedicated ignition coil circuit structure; Figure 7 Schematic diagram of discharge voltage monitoring circuit; Figure 8 Filtering circuit principle Figure 1 ; Figure 9 Filtering circuit principle Figure 2 ; Figure 10Principle of Ignition Energy Control Unit Figure 1 ; Figure 10a : Discharge waveform diagram of the auxiliary ignition coil in the ignition energy control unit; Figure 11 Principle of Ignition Energy Control Unit Figure 2 ; Figure 12 Ignition control process Figure 1 ; Figure 13 Ignition control process Figure 1 Output waveform of the ignition energy control unit under the control strategy; Figure 14 Based on the plasma voltage output waveform Figure 1 ; Figure 15 Based on the plasma voltage output waveform Figure 2 ; Figure 16 Waveforms showing the control effect of plasma voltage at different flow velocities; Figure 17 Schematic diagram of pulse current combustion diagnosis in ignition energy control unit Figure 1 ; Figure 18 Schematic diagram of pulse current combustion diagnosis in ignition energy control unit Figure 2 ; Figure 19 Schematic diagram of plasma impedance combustion diagnosis; Figure 20 Ignition control process Figure 2 .

[0029] Figure label: 1. Dedicated ignition coil; 11. Primary coil; 12. Secondary coil; 13. Switching element; 14. High voltage input terminal; 15. Plasma current detection terminal; 16. Unidirectional circuit one; 17. Unidirectional circuit two; 18. Discharge voltage monitoring circuit; 2. Ignition energy control unit; 21. Auxiliary ignition coil; 22. DC step-up transformer; 23. Field effect diode; 3. Main control unit; 31. Plasma feedback signal; 32. Combustion feedback signal; 33. Control signal; 34. High voltage wire; 4. Cylinder; 5. Spark plug. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, an internal combustion engine ignition control system includes at least one ignition control module. The ignition control module has a signal input terminal for receiving ignition signals from the engine electronic control unit and a high-voltage output terminal for coupling with the spark plug gap to provide ignition energy. The ignition control module provides and controls ignition energy in real time according to the dynamic demand in the engine cylinder during the ignition duration.

[0032] In this embodiment, the ignition signal from the engine electronic control unit drives the ignition timing of each cylinder through the ignition module, and provides appropriate ignition energy to each cylinder to enhance the ignition effect and thus promote combustion stability. This invention has a wide range of applications, including high-speed automotive engines, low-speed marine engines, stationary internal combustion engine power generation systems, and gas turbine systems. This ignition system features adaptive intelligent ignition logic, which can automatically determine the required ignition energy according to different application scenarios.

[0033] A specific embodiment of the ignition control module can be as follows: Figure 2 As shown. The ignition control module includes a main control unit 3, at least one ignition energy control unit 2, and at least one dedicated ignition coil 1. The output terminals of the dedicated ignition coil 1 and the ignition energy control unit 2 are both coupled to the spark plug gap. The main control unit 3 receives the in-cylinder plasma feedback signal provided by the dedicated ignition coil 1. The main control unit 3 also receives the combustion feedback signal 32 provided by the dedicated ignition coil 1 and the ignition energy control unit 2. The main control unit 3 outputs a control signal 33 to the ignition energy control unit 2 and the dedicated ignition coil 1 according to the dynamic demand in the engine cylinder to provide and control the ignition energy in real time.

[0034] The dedicated coil's function is to establish a breakdown voltage, thereby creating a plasma channel that allows the ignition energy control unit to discharge into the spark gap. Furthermore, the dedicated coil also includes a plasma channel voltage detection circuit and a combustion diagnostic circuit. The ignition energy control unit 2 provides a continuous power supply current to the spark gap during the continuous discharge phase. The amplitude and duration of this current can be significantly higher than that of the dedicated ignition coil 1, thus significantly improving ignition efficiency. The ignition energy control unit 2 has the function of adjusting the discharge current amplitude and duration in real time within microseconds based on the control signal 33 from the main control unit 3, enabling adjustments to the ignition strategy based on the engine cycle. The main control unit 3 can determine the engine's ignition energy requirements through plasma channel impedance signals and combustion diagnostic signals, and then control the amplitude and duration of the ignition energy released by the ignition energy management module into the spark gap in real time.

[0035] In a typical implementation, it can be as follows: Figure 3As shown. The ignition control module includes a main control unit 3, an ignition energy control unit 2, and multiple dedicated ignition coils 1. The number of dedicated ignition coils 1 corresponds to the number of spark plugs. The output terminal of a single dedicated ignition coil 1 is coupled to the gap of a single spark plug. The ignition energy control module has multiple identical output terminals, which are coupled to the gaps of each spark plug and are connected in parallel with the high-voltage output terminal of the dedicated coil.

[0036] One ignition energy control unit 2 can be shared by multiple engine cylinders 4, thereby reducing system complexity and manufacturing costs. The maximum output voltage of the ignition energy control unit 2 needs to be maintained at a low level (1kV~4kV), unable to independently break down, and can only discharge to the spark gap through a plasma channel already established by the dedicated ignition coil 1, thus automatically avoiding the possibility of the ignition energy control unit 2 discharging to cylinders 4 in non-combustion strokes. When the ignition energy control unit 2 is shared by multiple cylinders 4, the discharge time of the ignition energy control unit 2 must be within the time window when a plasma channel already exists in the spark gap of the ignition cylinder 4, that is, the discharge begins only after the dedicated coil has completed breakdown and established a plasma channel, and the discharge time cannot be later than the duration of the independent discharge of the dedicated coil. A one-way high-voltage isolation device is arranged between the ignition energy control unit 2 and the dedicated ignition coil 1 to ensure that the dedicated coil and the ignition energy control unit 2 do not affect each other during the discharge process, and that the discharge process of the dedicated coils of each cylinder 4 does not affect each other.

[0037] like Figure 4 The diagram shows a typical implementation of a four-cylinder engine. The system is equipped with four dedicated ignition coils 1, each used by one of the four cylinders 4, to initiate the breakdown process, while the ignition energy control unit 2 is shared by all four cylinders. Figure 5 The demonstration shows the discharge waveforms of an ignition energy control unit 2 supplying energy to two spark gaps. During the discharge process of the ignition energy control unit 2, discharge voltage can be detected in both spark gaps, but the current can only flow to the working cylinder 4 through the established plasma channel. By precisely controlling the discharge time difference between the dedicated ignition coil 1 and the ignition energy control system, no additional transistors or field-effect transistors are needed to control which cylinder the energy released by the ignition energy control system goes to, greatly reducing the complexity of the system.

[0038] In a more preferred embodiment, the dedicated ignition coil 1 includes a primary coil 11 and a secondary coil 12. The primary coil 11 is connected to a switching element 13 for receiving ignition signals, and the secondary coil 12 has an output terminal coupled to the spark plug gap. The high-voltage output terminal of the ignition energy control unit 2 is coupled to the spark plug gap.

[0039] like Figure 6The hardware circuit structure of the dedicated ignition coil is demonstrated. The dedicated ignition coil 1 includes a primary coil 11 and a secondary coil 12. The primary coil 11 is connected to a switching element 13 to receive the ignition signal, and the secondary coil 12 has a high-voltage input terminal 14 to provide continuous ignition current. The dedicated ignition coil 1 needs a high boost ratio to generate a high breakdown voltage (40~60kV) to ensure a stable breakdown process under different engine operating conditions. Unlike traditional ignition coils, in this invention, the ignition energy is mainly provided by the ignition energy management system, rather than by the dedicated ignition coil 1 itself. Therefore, the inductance of the primary and secondary coils 12 of the dedicated ignition coil 1 can be much lower than that of traditional coils, thus enabling a rapid charging and discharging process. The energy stored in the primary coil 11 of the dedicated ignition coil 1 is mainly determined by the parasitic capacitance of the ignition system and the required breakdown voltage; only the minimum energy required to reach the breakdown voltage is needed. Thus, the charging duration of the dedicated ignition coil 1 can be as low as 20~100 microseconds. This rapid charging process allows the engine to re-break down within 1°CA, effectively suppressing the negative impact on the combustion phase caused by a slow afterfire process. Lower secondary inductance also reduces power loss during discharge, thereby lowering the ignition coil's power consumption.

[0040] In a more preferred embodiment, one end of the secondary coil 12 is a plasma current detection terminal 15, used to detect the continuous ignition current. A discharge voltage monitoring circuit 18 is connected between the secondary coil 12 and the primary coil 11. Its purpose is to detect the impedance of the spark plasma and transmit the impedance signal to the main control unit 3. Both discharge voltage and discharge current can be used to diagnose plasma impedance. In addition to the secondary high-voltage interface directly connected to the spark plug 5, the dedicated ignition coil 1 also has a high-voltage input terminal 14 connected to the ignition energy management system, thereby directly transferring ignition energy from the ignition energy control unit 2 to the spark gap.

[0041] In a more preferred embodiment, a unidirectional circuit 16 is connected to the plasma current detection terminal 15 of the secondary coil 12. The unidirectional circuit 16 may be a high-voltage diode D1 connected to the ion current detection terminal 15, used to prevent the high voltage generated by the dedicated ignition coil during charging from being transmitted along the high-voltage line to the ignition energy control unit, and also to prevent accidental breakdown during the spark gap during charging.

[0042] In a more preferred embodiment, a unidirectional circuit 17 is connected to the high-voltage input terminal 14 of the secondary coil 12. The unidirectional circuit 17 may be a high-voltage diode D3 connected in series with the high-voltage input terminal 14, with the same direction as the high-voltage diode D1, used to prevent the high voltage generated by the dedicated ignition coil 1 from propagating in the reverse direction along the high-voltage connection line, thereby isolating interference between the engine cylinders 4 during the ignition process.

[0043] In a more preferred embodiment, the dedicated ignition coil 1 includes a discharge voltage monitoring circuit 18 for collecting the plasma voltage signal inside the engine cylinder and providing it to the main control unit 3.

[0044] The discharge voltage monitoring circuit 18 includes a first voltage divider element and a second voltage divider element connected to the secondary coil 12, and a discharge voltage monitoring terminal is connected between the first voltage divider element and the second voltage divider element. Figure 6 The diagram illustrates a circuit diagram of a dedicated ignition coil 1 for measuring discharge voltage. This dedicated ignition coil 1 includes a primary coil 11 and a secondary coil 12. One end of the primary coil 11 is connected to a power source, and the other end is connected in series with a transistor. This transistor acts as a switching element 13 to control the charging and discharging process of the ignition coil. One end (output terminal) of the secondary coil 12 is directly connected to the spark plug 5, transmitting the high voltage generated by the secondary coil to the spark gap, thus causing a breakdown. A first high-voltage diode D1 is connected in series between the output terminal of the secondary coil 12 and the spark plug 5. The other terminal of the secondary coil 12 is left floating for ion current detection. In the secondary circuit, a first resistor R1 and a second resistor R2 are connected in series. The other end of the first resistor R1 is connected to the secondary output circuit, positioned downstream of the first high-voltage diode D1 and upstream of the spark gap. The other end of the second resistor R2 is grounded. The plasma voltage is detected by the first resistor R1 and the second resistor R2; the ratio of the resistance values ​​of the first resistor R1 and the second resistor R2 determines the ratio of the detected voltage to the actual stimulation output voltage. For example, if the resistance of the first resistor R1 is 1000 times that of the second resistor R2, then the measured plasma voltage signal will be only one-thousandth of the actual plasma voltage. A noise reduction circuit, including a pair of Zener diodes and a capacitor connected in reverse, is also arranged between the detection line and the ground wire to reduce detection noise. Real-time detection of the plasma voltage allows for the prediction of potential plasma blow-off and re-breakdown phenomena.

[0045] like Figure 7 This demonstrates another implementation of the discharge voltage monitoring circuit 18. The discharge voltage detection circuit is based on capacitive voltage divider, and includes capacitors C1 and C2 connected in series. The component connections are similar to those in the resistor-based voltage divider circuit. One end of capacitor C1 is connected to the secondary output, and one end of capacitor C2 is connected to ground. The plasma voltage detection point is located between C1 and C2, so the ratio of the capacitance values ​​of C1 and C2 determines the attenuation factor of the detected voltage relative to the actual secondary discharge voltage. To ensure a fast instantaneous response time for the detected voltage, the capacitance values ​​of capacitors C1 and C2 cannot be too large. For example, to ensure a response time in the µs range, the capacitance values ​​of capacitors C1 and C2 must be below the µF range.

[0046] In a more preferred embodiment, a filter circuit is also connected across the second voltage divider element. Specifically, this can be achieved using... Figure 8 and Figure 9 As shown, a low-pass filter can be implemented by connecting a resistor Rs in series with the detection circuit and a capacitor Cs in parallel with the detection terminal. The low-pass filter eliminates the high-frequency components of the actual secondary voltage, including high-frequency electrical noise and instantaneous discharge voltage, which is more beneficial for ignition diagnosis during the arc discharge stage. Real-time detection of the plasma voltage allows for prediction of potential plasma blow-off and re-breakdown phenomena. A high-pass filter can be implemented by connecting a capacitor Cs in series with the detection terminal and a resistor Rs in parallel. The high-pass filter retains high-frequency signals and instantaneous discharge voltage, which is beneficial for the analysis and diagnosis of the breakdown stage. The cutoff frequencies of the low-pass and high-pass filters are related to the resistor Rs and the capacitor Cs.

[0047] In a more preferred embodiment, the turns ratio of the secondary coil 12 to the primary coil 11 is between 70:1 and 120:1.

[0048] In a more preferred embodiment, the ignition energy control unit 2 includes a plurality of auxiliary ignition coils 21 arranged in parallel, each auxiliary ignition coil 21 being connected to a high-voltage diode and then coupled to the spark plug gap.

[0049] like Figure 10 The diagram illustrates the hardware circuit structure of an ignition energy control unit 2. The ignition energy control unit 2 includes multiple auxiliary ignition coils 21 connected in parallel. Each auxiliary ignition coil 21 is connected to a high-voltage diode and then to a high-voltage output terminal. The ignition energy control unit 2 is used to provide ignition energy to the spark gap. This module can flexibly adjust the ignition current intensity and ignition duration to quickly control the plasma impedance, thereby enhancing ignition capability while preventing the plasma channel from being blown off or experiencing re-breakdown during spark discharge. A high-voltage diode is arranged downstream of the secondary output terminal of each auxiliary ignition coil 21 to isolate the discharge process between the auxiliary ignition coils 21. The downstream terminals of the three high-voltage diodes are connected together and then pass through a discharge current detection circuit. The discharge current signal can be quickly transmitted to the main control unit 3 to determine the required ignition current intensity and duration. Figure 10a The demonstration shows the discharge current when using a strategy with three auxiliary ignition coils 21, each with a charging duty cycle of 33% and 67%. Both duty cycles produce a continuous, sustained discharge current. However, due to the different charging times, the 67% duty cycle results in a higher discharge current level. Because the duty cycle of the auxiliary ignition coils 21 is controlled by an FPGA, microsecond-level switching of the discharge current level is possible, enabling transient switching of the discharge current according to changes in engine operating conditions.

[0050] In a more preferred embodiment, the turns ratio of the auxiliary ignition coil 21 is between 25:1 and 40:1. This turns ratio allows the discharge current during the stable discharge phase to be increased to 2-3 times that of the dedicated coil, thus enhancing the ignition effect. However, this design significantly reduces the achievable discharge voltage, making it unable to independently complete the breakdown process. Therefore, it is necessary to rely on the dedicated ignition coil 1 to first establish an ignition channel, and then release a high current into the channel. During the discharge process, the transient discharge current within microseconds can be increased or decreased by changing the duty cycle and operating frequency of the charging and discharging signals of the auxiliary coil group, thereby achieving rapid control of the plasma impedance. This part can be referred to... Figure 10a The instantaneous change of discharge current amplitude is a creative approach because in the past, if a dual-coil system wanted to achieve continuous discharge, the duty cycle had to be 50%. Otherwise, the plasma would be cut off when both coils were charging. Only with a strategy of three or more coils could the current level be changed by altering the coil charging duty cycle. For example, with three coils, continuous discharge could be achieved with duty cycles of 33.3% and 67% for each coil. However, since the primary coil charging time was doubled, the discharge level could also be doubled. Moreover, this could be a transient process. If the primary charging voltage was changed, the time required would be much longer, which would not meet the requirements of transient control.

[0051] In a more preferred embodiment, the ignition energy control unit 2 includes a DC boost transformer 22, an energy storage capacitor, and a field-effect diode 23. One side of the DC boost transformer 22 is connected to the power supply, the other side is connected to the energy storage capacitor, and then connected to the high-voltage output terminal through the field-effect diode 23 and finally connected to the high-voltage input terminal 14 of the secondary coil 12 of the dedicated ignition coil 1.

[0052] Specific examples Figure 11 As shown. The ignition energy control unit 2 includes a DC-DC boost transformer 22 and a field-effect diode 23. One side of the DC-DC boost transformer 22 is connected to the power supply, and the other side is connected to the field-effect diode 23 and then to the high-voltage output terminal, which is ultimately connected to the high-voltage input terminal 14 of the secondary coil 12 of the dedicated ignition coil 1. After passing through the high-frequency DC-DC boost transformer 22, the ignition energy is stored in a capacitor at a higher voltage, and the release of the current is controlled by the field-effect diode 23. The intensity of the discharge current can be controlled by adjusting the voltage, while the field-effect diode 23 can control the timing and duration of the discharge current. The discharge current signal is still transmitted to the intelligent control unit through the current detection module to achieve on-demand control.

[0053] The high-frequency DC step-up transformer 22 needs to operate at a sufficiently high frequency to ensure that the voltage of the energy storage capacitor remains at a relatively stable level during discharge. Assuming a discharge voltage of 2kV and a discharge current of 200mA~1000mA, the transient power of the high-voltage capacitor can reach 400~2000W. Taking a battery discharge duration of 3 milliseconds as an example, the power of the ignition module can reach 30~150W per cylinder. To achieve transient control of this high voltage and high current, a high-power field-effect diode 23 is needed to manage the discharge current intensity and duration. The voltage of the energy storage capacitor needs to be lower than the breakdown voltage but higher than the voltage across the spark gap during discharge to ensure a boost to the ignition current. The discharge current intensity is mainly determined by the voltage of the energy storage capacitor and the impedance of the discharge circuit. To ensure the discharge current intensity, the internal resistance of the spark plug 5 needs to be reduced from the traditional 4~5 kΩ to 1~2 kΩ to generate a discharge current of 200~2000mA.

[0054] Based on the hardware structure of the ignition control system described above, another embodiment of the present invention proposes an ignition control method, which specifically includes the following steps: S1, the initial ignition stage, after the dedicated ignition coil 1 receives the ignition command, the secondary coil 12 provides high voltage to achieve breakdown and establish a plasma channel in the spark gap. S2, continuous ignition stage: After the plasma channel is established, a continuous ignition current is provided for the spark gap. S3. During the continuous ignition phase, the impedance change of the plasma channel in the internal combustion engine cylinder is acquired, and the continuous ignition current is adjusted in real time according to the impedance change to ensure that the plasma is not interrupted by the airflow in the cylinder during the target discharge duration.

[0055] Based on the foregoing description of the dedicated ignition coil 1 and the ignition energy control unit 2, the dedicated coil's function is to establish a breakdown voltage, thereby creating a plasma channel that allows the ignition energy management module to discharge into the spark gap. Furthermore, the dedicated coil also includes a plasma channel voltage detection circuit and a combustion diagnostic circuit. The ignition energy control unit 2's function is to provide a continuous power supply current to the spark gap during the continuous discharge phase. The amplitude and duration of this current can be significantly higher than the capability of the dedicated ignition coil 1, thus significantly improving ignition efficiency. The ignition energy control unit 2 can adjust the discharge current amplitude and duration in real-time within microseconds based on the control signal 33 from the main control unit 3, enabling adjustments to the ignition strategy based on the engine cycle. The main control unit 3 can determine the engine's ignition energy requirements using the plasma channel impedance signal and the combustion diagnostic signal, and then control the amplitude and duration of the ignition energy released by the ignition energy management module into the spark gap in real-time.

[0056] Therefore, in the embodiments provided by the present invention, the ignition process is divided into an initial ignition stage and a continuous ignition stage. During the continuous ignition stage, the amplitude level and duration of the continuous ignition current provided by the ignition energy control unit 2 are adjusted in real time according to the plasma channel impedance and combustion state in the engine cylinder, so that the in-cylinder ignition state always maintains healthy and efficient flame core propagation.

[0057] In this embodiment, the dedicated ignition coil 1 only needs to reach the minimum breakdown energy requirement to complete the initial ignition process. At the beginning of the initial ignition stage, this method needs to provide a continuous ignition current to the output of the secondary coil 12 of the dedicated ignition coil 1 during the sustained ignition stage to provide ignition energy to the spark gap. In this step, the ignition current intensity and ignition duration can be flexibly adjusted to quickly control the plasma impedance, thereby enhancing the ignition capability while avoiding the plasma channel being blown off or undergoing re-breakdown during spark discharge. In step S3, the continuous ignition current needs to be adjusted according to the changes in the plasma channel impedance in the internal combustion engine cylinder to adjust the plasma channel impedance. Both the combustion diagnostic signal and the plasma impedance signal are received by the intelligent control system, and the ignition signal is actively adjusted within microseconds based on the two signals. This rapid control and response speed can adjust the ignition strategy within the engine cycle according to actual needs, maintaining stable combustion in lean and diluted combustion environments and improving engine efficiency.

[0058] In a more preferred embodiment, in step S3, the discharge voltage of the plasma in the plasma channel is obtained to obtain the change in plasma channel impedance; when the discharge voltage of the plasma exceeds a certain preset threshold, the ignition current amplitude level of the spark gap is increased by the ignition energy control unit 2.

[0059] Specifically, in step S3, the discharge voltage of the plasma in the plasma channel is obtained to obtain the change in plasma channel impedance; when the discharge voltage of the plasma exceeds a certain preset threshold, the continuous ignition current amplitude is increased by the ignition energy control unit 2. See details. Figure 12 , Figure 13 , Figure 14 , Figure 15 An increase in plasma impedance will correspondingly increase the plasma discharge voltage. A discharge voltage threshold is set in the control logic; when the discharge voltage exceeds this threshold, a control command to increase the discharge current level will be triggered. In actual spark discharge processes, the plasma voltage may suddenly increase before re-breakdown occurs due to plasma elongation, such as... Figure 14As shown. When the voltage required to maintain the plasma is lower than the voltage required for re-breakdown, the re-breakdown process is triggered, interrupting the previous plasma channel. When the plasma voltage increases above the set threshold, the intelligent control module outputs a command to increase the discharge current, and within 3 microseconds, the ignition energy control unit 22 adjusts the discharge current to a higher level, thereby reducing the discharge voltage and maintaining the spark discharge process.

[0060] In practical applications, to ensure the durability of the spark plug at 5 sparks and reduce the degree of electro-corrosion, this high discharge current can be provided in a pulsed manner, rather than continuously when not needed, such as... Figure 15 As shown, without real-time adjustment of the plasma impedance, there will be a total of 5 re-breakdown events during the 1.5ms discharge process; however, when a high-current pulse signal is used to adjust the plasma impedance, the re-breakdown event can be prevented.

[0061] like Figure 16 The effect of this control method at different flow velocities is demonstrated. The flow velocities range from 3 to 22 m / s. When the flow velocity is low, the plasma stretching is low, and the discharge voltage remains below the threshold, thus preventing the triggering of pulse current. However, when the flow velocity increases, leading to re-breakdown, the frequency of the triggered pulse current also increases. This dynamically controls the sudden increase in plasma impedance caused by high flow velocities, thereby maintaining the stability of the discharge process.

[0062] like Figure 20 As shown. In a more preferred embodiment, in step S3, the in-cylinder gas flow rate is determined before the impedance change. If the in-cylinder flow rate is low, a first control strategy is adopted for the continuous ignition current; if the in-cylinder flow rate is high, a second control strategy is adopted for the continuous ignition current.

[0063] For example, in the first control strategy, the continuous ignition current uses a first power output and has a first discharge duration. The in-cylinder flow velocity can be determined by the discharge voltage change rate during continuous ignition. When the discharge voltage change rate of the continuous ignition current is higher than a certain threshold, it indicates that the in-cylinder flow is at a high velocity, and vice versa. In the low-velocity plasma channel, a high-power, short-discharge-duration ignition current control method is required.

[0064] It should be noted that judging the plasma channel flow rate and adopting different control strategies is to broaden the application range of the control method proposed in this invention. The in-cylinder gas flow rate is related to the engine's operating conditions. In the common operating conditions of high-speed engines, the corresponding in-cylinder gas flow rate is relatively high; similarly, in the operating conditions of low-speed engines, the in-cylinder gas flow rate is relatively low. For example, passenger car engines and large marine engines exhibit the aforementioned differences. When the plasma channel flow rate is low, fine control of the continuous ignition current during the continuous ignition phase will be of little effect because the in-cylinder gas flow rate is slow, the plasma flow rate is low, and the flame core propagation is slow. Increasing the discharge duration cannot effectively improve the plasma ignition capability. Therefore, in this operating condition, a more direct high-power (50~200kW), short discharge duration (50μs~1ms) control strategy can be adopted. Therefore, by judging the ion channel flow rate, this invention can adopt a matched control method according to the different engine operating conditions, thus having a wider range of applicable scenarios.

[0065] In a more preferred embodiment, the second control strategy predicts the re-breakdown probability of the plasma channel; if the re-breakdown probability is high, the continuous ignition current amplitude level is increased.

[0066] In this embodiment, the probability of plasma channel re-breakdown can be predicted by acquiring the discharge voltage change rate and amplitude of the continuous ignition current. The impedance of the plasma channel is closely related to its length and ionization degree. Generally, the longer the plasma channel and the lower the plasmaization degree, the higher the impedance of the plasma channel. When the gas flow in the cylinder causes the plasma channel to leave the spark gap, lengthening the plasma channel, the impedance of the plasma channel will increase accordingly, one manifestation of which is the increase in discharge voltage, such as... Figure 14 As shown, when the discharge voltage increases to a certain level, it can trigger re-breakdown near the spark gap. Re-breakdown will form a new plasma channel with lower impedance, thus short-circuiting the original plasma channel. This causes the discharge current to no longer flow through the original plasma channel, eventually disappearing and resulting in an unstable and dispersed initial fire nucleus. If a threshold below the re-breakdown voltage is set, the discharge voltage can be reduced before re-breakdown occurs, thus preventing the plasma from having the conditions for re-breakdown near the spark gap.

[0067] In a more preferred embodiment, the second control strategy determines the plasma channel flow rate by the rate of change of the discharge voltage of the continuous ignition current. When the rate of change of the discharge voltage of the continuous ignition current is higher than a certain threshold, it indicates that the plasma channel flow rate is high, and vice versa. The plasma channel exhibits a rapid increase in impedance before its stability decreases, so the rate of change of discharge voltage can also be used as a basis for judging the possibility of re-breakdown. The advantage of using this method is its wider applicability. Because the re-breakdown voltage is greatly affected by the environment and is related to multiple factors such as engine operating conditions, background pressure, air-fuel mixture density, and spark plug gap, it is difficult to find a single, fixed threshold to serve as a uniform reference for all operating conditions. If the threshold is set too low, it will trigger high current demands more frequently, increasing system power consumption and spark plug galvanic corrosion; if the threshold is set too high, re-breakdown may occur under certain engine operating conditions, affecting ignition performance.

[0068] In a more preferred embodiment, the second control strategy further includes combustion diagnosis. If there is a high probability of re-breakdown and the combustion diagnosis is normal, the continuous ignition current amplitude level is increased; if there is a high probability of re-breakdown but the combustion diagnosis shows partial combustion, the continuous ignition current amplitude level is increased and the discharge duration is increased; if there is a low probability of re-breakdown but the combustion diagnosis shows partial combustion, the discharge duration of the continuous ignition current is increased.

[0069] Specific combustion diagnosis can be implemented as follows: after the initial ignition phase, the discharge voltage or discharge current of the continuous ignition current is acquired. If the discharge voltage or discharge current of the continuous ignition current cannot be acquired, partial combustion is diagnosed; otherwise, normal combustion is diagnosed. Specifically, as follows... Figure 17 ,as well as Figure 18 As shown. When a continuous ignition current is generated, a signal with a specific frequency and duty cycle is generated, synchronized with the discharge initiation time, thus producing a high-frequency, high-voltage pulse in the spark gap after the breakdown process. If ignition is successful, the high ion concentration in the initial flame core and flame front allows the high-voltage pulse to discharge successfully, forming a discharge current, without the need for a dedicated ignition coil 1 to provide a higher discharge voltage. The frequency, duty cycle, and current level of the high-voltage pulse required for accurate combustion diagnosis are mainly determined by the charged ion density of the air-fuel mixture near the spark plug 5 gap. The high-voltage pulse signal parameters need to be precisely adjusted according to the combustion conditions to ensure that discharge is not successful when the flame core is weak and the charged particle concentration is low, while it can discharge automatically when the flame core is stable. Figure 17As shown, in an air environment, the high-voltage pulse can only discharge simultaneously when the dedicated ignition coil 1 is discharging. However, once the discharge of the dedicated ignition coil 1 has ended, the rapid increase in plasma channel impedance will prevent the high-voltage pulse from discharging into the spark gap. However, when a successful ignition nucleus exists near the spark gap, such as... Figure 18 As shown, the high-voltage pulse can still discharge into the spark gap 3ms after the discharge of the dedicated ignition coil 1, thus proving that the flame core propagation is good. Compared with the traditional example current, the advantage of this detection method is that it can provide flame detection during the discharge duration and has a faster detection speed. Figure 19 The diagram illustrates a strategy for combustion diagnostics based on plasma impedance (voltage change rate). Two discharge waveforms are shown, both acquired at the same flow rate: the first using air, and the second using a combustible mixture. As the airflow propels the plasma, its impedance increases, resulting in a time-varying spark discharge voltage for both gases. However, due to the lower impedance of the combustible mixture, the impedance change is less pronounced under the same airflow velocity, leading to a lower discharge voltage growth rate compared to the air-based plasma. This information can be rapidly acquired and processed by an FPGA for real-time control of the ignition duration or ignition current intensity.

[0070] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An internal combustion engine ignition control system, characterized in that, It includes at least one ignition control module, which has a signal input terminal for receiving ignition signals from the engine electronic control unit and an output terminal for coupling with the spark plug gap to provide ignition energy. The ignition control module provides and controls ignition energy in real time according to the dynamic demand in the engine cylinder during the ignition duration.

2. The internal combustion engine ignition control system as described in claim 1, characterized in that, The ignition control module includes a main control unit, at least one ignition energy control unit, and at least one dedicated ignition coil. The output terminals of the dedicated ignition coil and the ignition energy control unit are connected in parallel and then connected in series with the spark plug gap. The main control unit receives the in-cylinder plasma feedback signal provided by the dedicated ignition coil. The main control unit also receives the combustion feedback signal provided by the dedicated ignition coil and the ignition energy control unit. The main control unit outputs control signals to the ignition energy control unit and the dedicated ignition coil according to the dynamic demand in the engine cylinder to provide and control ignition energy in real time.

3. The internal combustion engine ignition control system as described in claim 2, characterized in that, The ignition control module includes a main control unit, an ignition energy control unit, and multiple dedicated ignition coils. The number of dedicated ignition coils corresponds to the number of spark plugs. The output terminal of a single dedicated ignition coil is coupled to the gap of a single spark plug. The output terminal of the ignition energy control module is coupled to the gap of each spark plug.

4. The internal combustion engine ignition control system as described in claim 2, characterized in that, The dedicated ignition coil includes a primary coil and a secondary coil. The primary coil is connected to a switching element to receive an ignition signal, and the secondary coil has an output terminal coupled to the spark plug gap. The high-voltage output terminal of the ignition energy control unit is coupled to the spark plug gap.

5. The internal combustion engine ignition control system as described in claim 4, characterized in that, A unidirectional circuit two is connected between the high-voltage output terminal of the ignition energy control unit and the output terminal of the secondary coil of the dedicated ignition coil.

6. The internal combustion engine ignition control system as described in claim 4, characterized in that, The dedicated ignition coil includes a discharge voltage monitoring circuit, which is used to collect the plasma voltage signal in the engine cylinder and provide it to the main control unit.

7. The internal combustion engine ignition control system as described in claim 4, characterized in that, The ignition energy control unit includes multiple auxiliary ignition coils arranged in parallel. Each auxiliary ignition coil is connected to a high-voltage diode and then coupled to the spark plug gap.

8. The internal combustion engine ignition control system as described in claim 7, characterized in that, The number of auxiliary ignition coils is n, and the duty cycle of the output discharge current of each auxiliary ignition coil is the same and ranges from 1 / n to (n-1) / n, where n is a natural number not less than 3.

9. The internal combustion engine ignition control system as described in claim 7, characterized in that, The turns ratio of the auxiliary ignition coil is between 25:1 and 40:

1.

10. The internal combustion engine ignition control system as described in claim 4, characterized in that, The ignition energy control unit includes a DC boost transformer, an energy storage capacitor, and a field-effect diode. One side of the DC boost transformer is connected to the power supply, and the other side is connected to the energy storage capacitor. It is then connected to the high-voltage output terminal through the field-effect diode and finally connected in parallel with the high-voltage output terminal of the secondary coil of the dedicated ignition coil, and finally coupled to the spark gap.

11. An ignition control method for an internal combustion engine, characterized in that, The ignition control system described in any one of claims 2 to 10 is adopted, and specifically includes the following steps: S1, the initial ignition stage, after the dedicated ignition coil receives the ignition command, its secondary coil provides high voltage to achieve breakdown and establish a plasma channel in the spark gap. S2, continuous ignition stage: After the plasma channel is established, a continuous ignition current is provided for the spark gap. S3. During the continuous ignition phase, the impedance change of the plasma channel in the internal combustion engine cylinder is acquired, and the amplitude of the continuous ignition current is adjusted in real time according to the impedance change to ensure that the plasma is not interrupted by the airflow in the cylinder during the target discharge duration.

12. The internal combustion engine ignition control method as described in claim 11, characterized in that, In step S3, the discharge voltage of the plasma in the plasma channel is obtained to obtain the change in plasma channel impedance; when the discharge voltage of the plasma exceeds a certain preset threshold, the ignition current amplitude level of the spark gap is increased by the ignition energy control unit.

13. The internal combustion engine ignition control method as described in claim 12, characterized in that, In step S3, the flow rate of the gas flow in the cylinder is determined based on the change in the initial impedance of the plasma. If the flow rate in the cylinder is low, a first control strategy is adopted for the continuous ignition current; if the flow rate in the cylinder is high, a second control strategy is adopted for the continuous ignition current.

14. The internal combustion engine ignition control method as described in claim 13, characterized in that, In the first control strategy, the continuous ignition current adopts a first power output and has a first discharge duration.

15. The internal combustion engine ignition control method as described in claim 13, characterized in that, In the second control strategy, the re-breakdown probability of the plasma channel is predicted. If the re-breakdown probability is high, the continuous ignition current amplitude level is increased.

16. The internal combustion engine ignition control method as described in claim 15, characterized in that, In the second control strategy, the discharge voltage change rate and amplitude of the continuous ignition current are obtained to predict the possibility of plasma channel re-breakdown.

17. The internal combustion engine ignition control method as described in claim 15, characterized in that, In the second control strategy, the flow rate of the gas in the cylinder passing through the spark gap is determined by the rate of change of the discharge voltage of the continuous ignition current.

18. The internal combustion engine ignition control method as described in claim 15, characterized in that, The second control strategy also includes combustion diagnosis. If there is a high probability of re-breakdown and the combustion diagnosis is normal, the continuous ignition current amplitude level is increased. If there is a high probability of re-breakdown but the combustion diagnosis shows partial combustion, the continuous ignition current amplitude level is increased and the discharge duration is increased. If there is a low probability of re-breakdown but the combustion diagnosis shows partial combustion, the discharge duration of the continuous ignition current is increased.

19. The internal combustion engine ignition control method as described in claim 18, characterized in that, The combustion diagnosis involves providing a pulsed current signal through the ignition energy control unit after the initial ignition phase, attempting to release a pulsed ignition current at a stimulation voltage lower than the re-breakdown voltage threshold during the spark gap, and monitoring the discharge voltage or discharge current signal at this time. If the actual ignition current signal cannot be obtained, it is diagnosed as partial combustion; otherwise, it is diagnosed as normal combustion.

20. The internal combustion engine ignition control method as described in claim 18, characterized in that, The combustion diagnosis is performed after the initial ignition phase, based on plasma impedance to determine whether combustion is normal.

21. The internal combustion engine ignition control method as described in claim 18, characterized in that, The combustion diagnosis is based on the rate of change of discharge voltage under the current continuous discharge current obtained after the initial ignition phase. If the rate of change is lower than the rate of change of discharge voltage of plasma in an air environment, the combustion is diagnosed as normal; otherwise, it is diagnosed as partial combustion.

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