Electronic circuit and capacitor discharge system comprising an electronic circuit

Abstract

This patent application discloses an electronic circuit (101) for controlling the spark of a spark plug (SP1) in a capacitor discharge ignition system (100) of an internal combustion engine. The electronic circuit (101) includes: an ignition coil (110) arranged to supply current to the spark plug (SP1); an ignition capacitor (C1) arranged to supply energy to a primary winding (L1); a voltage source (130) arranged to supply energy to at least one of the ignition capacitor (C1) and the primary winding (L1); a first switch (SW1) connected to a first primary terminal (TL1) and a first power supply terminal (TS1); a second switch (SW2) connected to a second capacitor terminal (TC2) and a second power supply terminal (TS2); and a third switch (SW3) connected to the second capacitor terminal (TC2) and the first power supply terminal (TS1). A capacitor discharge ignition system (100) including the above-mentioned electronic circuit (101) and an internal combustion engine including the capacitor discharge ignition system (100) are also disclosed.

Description

[0001] Cross-reference to related applications

[0002] This patent application claims the benefit of Swedish patent application number 2051548-2, filed on December 22, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of this patent application relate to ignition systems in spark-ignition internal combustion engines (SI-ICE), such as capacitor discharge ignition (CDI) systems. Examples of such internal combustion engines include natural gas and biogas-powered engines, hydrogen-powered engines, gasoline-powered engines, engines powered by alcohols such as methanol or ethanol, and engines powered by ammonia and other fuels suitable for SI-ICE applications. In particular, electronic circuitry for said systems and capacitor discharge ignition systems including said electronic circuitry, as well as internal combustion engines including such capacitor discharge ignition systems, are disclosed. Background Technology

[0004] An automotive ignition system generates a high-voltage discharge at the electrodes of one or more spark plugs to ignite the compressed air-fuel mixture. This discharge needs to be released when the piston is in a specific physical position within the cylinder. Furthermore, to optimize engine performance, improve fuel economy, minimize spark plug electrode wear, and reduce emissions, the timing and duration of the spark should be controlled according to a predetermined discharge profile.

[0005] like Figure 1 As shown, a typical CDI system has a capacitor C1 as an energy storage device. The stored energy is E = C1 * U. 2 / 2. When switch SW1 is open and switch SW4 is closed, voltage U is supplied to capacitor C1 by voltage source V1. When capacitor C1 has been charged to the predetermined voltage U, another switch SW4 is opened, and when switch SW1 is closed, the spark on the spark plug electrode is released as follows. Transformer T is connected to capacitor C1, which is arranged to supply a very high voltage to spark plug SP1. A high voltage is required on spark plug SP1 to generate plasma, i.e., a spark. To obtain the high voltage, several hundred volts are applied to the primary coil L1 of the transformer, which converts these several hundred volts to up to about 50kV, i.e., the high voltage required to generate a flashover, a spark.

[0006] The primary coil L1 of the transformer and the capacitor C1 constitute a frequency of The so-called resonant circuit. If it weren't for energy losses in the physical components of the CDI system, the resonance would continue indefinitely. These energy losses generate heat, thus reducing the energy output to the spark.

[0007] Figure 2The voltage across capacitor C1 (see solid line) and the current through primary coil L1 (see dotted line) as a function of time are shown. Additionally, a graph (see dashed line) shows the voltage across the spark gap or spark plug electrodes as a function of time. The graphs use different scales and units to improve readability. At time t0, as... Figure 1 The switch SW1 shown is open, and similarly... Figure 1 Another switch, SW4, is closed. At time t1, switch SW1 closes and another switch, SW4, opens to form a spark. As the voltage across the capacitor decreases, the current through the primary coil begins and increases. The increased current through the primary coil is converted into an increased voltage across the secondary coil. This voltage continues to rise until the voltage across the spark plug electrodes becomes too high, causing electrical breakdown and generating plasma between the spark plug electrodes—that is, the spark has been ignited. Due to the resonant circuit formed by capacitor C1 and transformer T (such a resonant circuit is known), the polarity of the spark subsequently changes alternately. Eventually, the spark extinguishes (not shown). Furthermore, Figure 3 The current through the spark gap (see solid line) and the current through the primary coil (see dotted line) are shown. Time t1 and Figure 2 same.

[0008] Various solutions exist for modifying the spark duration in a CDI system. For example, US6662792 discloses a capacitor discharge ignition (CDI) system capable of generating a strong, continuous discharge at the spark gap for a desired duration, and may include a second controllable power switch circuit whose input terminals are connected to the output terminals of a high-voltage DC power supply. The output terminals of the second controllable power switch circuit are connected to the input terminals of a first power switch circuit. The second controllable power switch circuit may also have control terminals connected to the output of a controller. The first controllable power switch circuit can be used to discharge the discharge capacitor, and the second controllable power switch circuit can be used to charge the discharge capacitor. Thus, during the charging and discharging cycles of the discharge capacitor, the ignition current through the system's ignition coil is enabled for any desired number of cycles. A series of ignition current signals allows the spark to be extended to any desired duration. However, this solution has disadvantages such as limited flexibility in generating a spark with desired characteristics and high production costs. For certain applications, particularly those requiring flexible spark characteristics and cost-effective solutions, such as SI-ICE fueled by alternative and renewable fuels, new, more cost-effective, and flexible solutions are needed. Summary of the Invention

[0009] One objective could be to at least alleviate the aforementioned disadvantages and / or problems.

[0010] According to one aspect, this objective is achieved by an electronic circuit for controlling the spark of a spark plug in a capacitor discharge ignition system of an internal combustion engine. The electronic circuit includes an ignition coil arranged to supply current to the spark plug. The ignition coil includes a primary winding having a first primary terminal and a second primary terminal, and a secondary winding to which the spark plug can be connected. The electronic circuit includes an ignition capacitor arranged to supply energy to the primary winding. The ignition capacitor has a first capacitor terminal and a second capacitor terminal. The first capacitor terminal is connected to the second primary terminal. The electronic circuit includes a voltage source arranged to supply energy to at least one of the ignition capacitor and the primary winding. The voltage source has a first power supply terminal and a second power supply terminal.

[0011] Furthermore, the electronic circuit includes a first switch, a second switch, and a third switch. The first switch is connected to a first primary terminal and a first power supply terminal. The second switch is connected to a second capacitor terminal and a second power supply terminal. The third switch is connected to a second capacitor terminal and a first power supply terminal.

[0012] According to another aspect, this objective is achieved by a capacitor discharge ignition system comprising the electronic circuitry of any of the embodiments disclosed in this patent application.

[0013] According to another aspect, this objective is achieved by an internal combustion engine that includes the capacitor discharge ignition system disclosed in this patent application.

[0014] Thanks to the first, second, and third switches, the electronic circuitry enables efficient and independent control of spark characteristics. Certain characteristics of the spark can be controlled by adjusting the voltage source, specifically the ignition voltage used to charge the ignition capacitor. For example, each of the following characteristics, including, for instance, spark duration, ignition voltage, and spark current, can be controlled independently of other characteristics according to at least some embodiments.

[0015] Therefore, one advantage is that at least some embodiments of this patent application achieve flexible control of the spark in a cost-effective manner, for example.

[0016] In some embodiments, the electronic circuitry includes a fourth switch connected to the second primary terminal and the second power supply terminal. In this way, requirements on the voltage source, for example, in terms of output voltage and / or output current, can be relaxed. Therefore, with the relaxation of requirements, the cost of the voltage source can be reduced.

[0017] In some embodiments, the electronic circuitry includes a fifth switch connected to the first capacitor terminal and the first power supply terminal. In this way, any residual charge held by the ignition capacitor can be discharged after the spark extinguishes, thereby resetting the charge state of the ignition capacitor. One advantage is that the charge state of the ignition capacitor can be known or defined, allowing subsequent sparks to be controlled as needed, i.e., starting from the known charge state of the ignition capacitor. This can be particularly useful for controlling the spark duration.

[0018] In some embodiments, the electronic circuitry includes a storage capacitor connected to a first power supply terminal and a second switch, and a sixth switch connected to the second power supply terminal and the storage capacitor. The second switch is indirectly connected to the second power supply terminal via the sixth switch connected to the second switch. In this way, the sum of voltages across the storage capacitor and the voltage source can be applied when the first switch is closed, the second switch is closed, the sixth switch is closed, the third switch is open, the fourth switch is open, and the fifth switch is open. Therefore, one advantage, for example, compared to at least some embodiments of this patent application, is that the maximum voltage requirement for the voltage source can be relaxed, i.e., a cost-effective solution.

[0019] In some embodiments, the electronic circuitry includes a control unit that can be configured to perform various methods to control one or more of the spark duration, ignition voltage, and spark current.

[0020] Therefore, one advantage is that when the electronic circuitry is used, for example in an internal combustion engine, it can achieve control of spark characteristics as disclosed in this patent application. Attached Figure Description

[0021] Various aspects of the embodiments disclosed in this patent application, including their specific features and advantages, will be readily understood from the following detailed description and accompanying drawings.

[0022] Figure 1 This is a general schematic diagram of an exemplary electronic circuit for a CDI system based on the prior art.

[0023] Figure 2 and Figure 3 It is shown in Figure 1 An exemplary current and voltage graph during the operation of a known electronic circuit.

[0024] Figure 4 This is a schematic circuit diagram of an exemplary electronic circuit according to an embodiment of this patent application.

[0025] Figure 5 This is a schematic circuit diagram of another exemplary electronic circuit according to an embodiment of this patent application.

[0026] Figure 6 and 7 It is shown in Figure 5 An exemplary current and voltage graph during the operation of an exemplary electronic circuit.

[0027] Figure 8 This is a schematic circuit diagram of another exemplary electronic circuit according to an embodiment of this patent application.

[0028] Figure 9 This is a schematic circuit diagram of another exemplary electronic circuit according to an embodiment of this patent application.

[0029] Figures 10a to 10d show some examples of spark control implemented by the electronic circuit disclosed in this patent application.

[0030] Figure 11 This is a schematic block diagram illustrating an exemplary internal combustion engine including an embodiment of the ignition system of this patent application. Detailed Implementation

[0031] Throughout the following description, similar reference numerals are used where applicable to denote similar features, such as nodes, actions, modules, circuits, parts, items, elements, units, etc.

[0032] Figure 4 An exemplary electronic circuit 101 is depicted for controlling the spark of spark plug SP1 in a capacitor discharge ignition system 100 for an internal combustion engine.

[0033] Electronic circuit 101 includes an ignition coil 110 arranged to supply current to spark plug SP1. Ignition coil 110 includes a primary winding L1 having a first primary terminal TL1 and a second primary terminal TL2, to which spark plug SP1 can be connected, and a secondary winding L2. In the case of multiple cylinders, each cylinder has a corresponding ignition coil.

[0034] The electronic circuit 101 also includes an ignition capacitor C1 arranged to supply energy to the primary winding L1. The ignition capacitor C1 has a first capacitor terminal TC1 and a second capacitor terminal TC2. The first capacitor terminal TC1 is connected to the second primary terminal TL2.

[0035] Furthermore, the electronic circuit 101 includes a voltage source 130, which is arranged to supply energy to at least one of the ignition capacitor C1 and the primary winding L1. The voltage source 130 has a first power supply terminal TS1 and a second power supply terminal TS2. The voltage source 130 can be powered by a 12V or 24V battery supplied with the internal combustion engine. The voltage source 130 can be an adjustable voltage source, such as a boost converter, a step-up converter, a buck-boost converter, etc.

[0036] The electronic circuit 101 further includes a first switch SW1 connected to a first primary terminal TL1 and a first power supply terminal TS1. In the case of multiple cylinders, each cylinder has a corresponding switch. This corresponding switch is connected to its corresponding cylinder in the same, similar to, or corresponding manner as the first switch SW1.

[0037] In addition, the electronic circuit 101 includes a second switch SW2 connected to the second capacitor terminal TC2 and the second power supply terminal TS2.

[0038] Figure 4 The electronic circuit 101 further includes a third switch SW3 connected to the second capacitor terminal TC2 and the first power supply terminal TS1.

[0039] The second switch SW2 and the third switch SW3, and their connection in the electronic circuit 101, can be switched to a position where energy is fed from the voltage source 130.

[0040] It is worth noting that throughout this invention, the switch is shown as an ideal switch. In practical implementation, a protection diode, additional components, and / or the like may be provided.

[0041] As used in this patent application, the term “connected to” may mean directly or indirectly connected to, i.e., via one or more other components.

[0042] As used in this patent application, the term "switch" may or may not include additional components such as diodes, protection diodes, etc.

[0043] In some cases, spark plug SP1 may be considered to be located in or included in a capacitor discharge ignition system. Spark plugs are typically in CDI systems because the spark ignition device of the spark plug is mounted at the cylinder where ignition is controlled, or on / in the cylinder.

[0044] Electronic circuit 101 may include control unit 120, such as microprocessor, microcontroller, processor circuit, central processing unit (CPU), etc.

[0045] According to any of the embodiments of this patent application, the control unit 120 can be arranged to open or close one or more switches of the electronic circuit 101. This can be accomplished by electrically connecting the control unit 120 (not shown) to a corresponding control port of each switch, such as the base of a transistor switch. The control of the switches will be described in more detail below.

[0046] In addition, the control unit 120 can be configured to measure current, such as secondary current.

[0047] An advantage of the embodiments according to this patent application is that a small ignition coil can be designed, a characteristic desired due to space constraints in modern SI-ICE applications. The small-sized coil can be designed using the CDI method because energy is stored in the ignition capacitor C1, unlike inductive ignition coils where energy is stored as a magnetic field in the core, resulting in a larger ignition coil to meet the requirements. Furthermore, less energy is needed to generate the initial spark (flashover) because more energy can be added as the spark runs (or illuminates), i.e., before it extinguishes. Therefore, a small-sized coil can be used while still meeting the spark characteristics required for modern SI-ICE applications.

[0048] In at least some embodiments, spark characteristics can be altered from one spark to another to improve combustibility and significantly reduce spark plug wear. Spark plug electrode wear is a well-known cost driver in SI-ICE applications due to electrode corrosion caused by the jetting of evaporating and molten electrode metal and by sputtering from impacts of high-energy particles on the electrode surface. Reduced spark plug electrode wear is achieved by adapting the spark to engine operating conditions and fuel characteristics, thereby avoiding or at least reducing excessive spark energy and / or power.

[0049] Furthermore, due to its low coil inductance and built-in active coil ringing suppression, this solution is well-suited for ion current-based combustion diagnostics. When the spark extinguishes, some residual energy remains in the resonant ignition circuit, causing it to "ring" back and forth, forming a decaying sinusoidal signal. This ringing interferes with ion current measurements and renders them useless until the ringing disappears. Clearly, by reducing the inductance in the resonant circuit, the residual (magnetic) energy is reduced, and therefore, the ringing is also reduced. Figure 8 The active coil ringing suppression provided by the fifth switch SW5 further reduces ringing, thereby improving ion current capability or ion sensing capability.

[0050] The embodiments of this patent application are particularly suitable for hydrogen fuel engines, which are generally more sensitive to so-called pre-ignition, in which the air-fuel mixture is unintentionally ignited before it should be. This can not only reduce engine efficiency but is also harmful to the engine, or even destroy it. Such pre-ignition can be caused by "spark at make," which may occur at the start of a pause in an induction ignition system or by hot spots in the combustion chamber, which may be due to excessive spark energy that can heat the spark plug electrodes. Due to the inherent physical properties of hydrogen, hydrogen-fueled SI-ICE engines can particularly benefit from controlled and flexible spark ignition, and this controlled and flexible ignition can be achieved through at least some of the embodiments in this patent application.

[0051] Go to Figure 5 The fourth switch SW4 has been added. Figure 4 The electronic circuit 101 may include a fourth switch SW4, which may be connected to the second primary terminal TL2 and the second power supply terminal TS2.

[0052] With the fourth switch SW4 closed, the first switch SW1 open, the second switch SW2 open, and the third switch SW3 closed, the ignition capacitor C1 can be charged without applying any voltage to the primary coil L1. Next, for spark ignition, the fourth switch SW4 is opened, the first switch SW1 is closed, the second switch SW2 is closed, and the third switch SW3 is open. Thus, the voltage on the ignition capacitor C1 and the voltage source voltage are applied in series to the primary coil L1.

[0053] Therefore, due to the fourth switch SW4, the voltage requirements for voltage source 130 can be relaxed. For example, it may only be necessary for voltage source 130 to be able to supply the voltage required by voltage source 130 in [the specific voltage range]. Figure 4 In this example, half of the voltage needs to be supplied. The ignition capacitor C1 can typically maintain a voltage approximately equal to that from... Figure 4 The maximum voltage obtainable from the voltage source 130.

[0054] In the following text, see references Figure 6 Show Figure 5 The operation of electronic circuit 101.

[0055] Figure 6 The voltage across capacitor C1 (see solid line) and the current through primary coil L1 (see dotted line) are shown as a function of time. Additionally, a graph (see dashed line) shows the voltage across the spark gap or spark plug SP1 as a function of time. The graphs use different scales and units for improved readability. At time t0, the first switch SW1 is open, and the fourth switch SW4 is closed. The third switch SW3 is closed, and the second switch SW2 is open. In this way, capacitor C1 is charged. At time t1, the first switch SW1 and the third switch SW3 are closed, and the second switch SW2 and the fourth switch SW4 are open to form a spark. As the voltage across the capacitor decreases, the current through the primary coil begins and increases. The increased current through the primary coil is converted into an increased voltage across the secondary coil. This voltage continues to rise until the voltage between the spark plug electrodes becomes too high, causing electrical breakdown and generating plasma between the spark plug electrodes—that is, the spark has been ignited. As the spark burns, the voltage across capacitor C1 and the current through the primary coil oscillate alternately.

[0056] After several oscillations, the solid line jumps due to the energy supplied synchronously with the oscillations. This prolongs the duration of the spark.

[0057] like Figure 7 As shown, this leads to Figure 6 The solid line jumps or irregular energy is from voltage source 130 and / or storage capacitor C2 (which will be combined with the following). Figure 8 The current supply (introduction) is provided. Control unit 120 can, for this purpose, open the third switch SW3 and close the second switch SW2 at time point t2. At another time point t3, control unit 120 can again close the third switch SW3 and open the second switch SW2. Switches SW1, SW2, SW3, and SW4 can remain unchanged until the oscillation decays and the spark extinguishes (not shown). Furthermore, Figure 7 The current through the spark gap (see solid line) and the current through the primary coil (see dotted line) are shown. Time t1 and Figure 6 The same as in [the previous sentence].

[0058] The table below explains how to do it. Figure 5 The electronic circuit is a switch to control the duration or length of a spark when it is generated. This means that when the switch is operated at the appropriate time in the following manner, a spark with the desired characteristics can be generated.

[0059]

[0060] In some examples (not shown in the attached tables / figures), electronic circuit 101 may include a fifth switch SW5 connected to the first capacitor terminal TC1 and the first power supply terminal TS1. In this way, any residual voltage held by the ignition capacitor C1 can be released to ground GND after the spark extinguishes, thereby resetting the charge state of the ignition capacitor C1. One advantage is that the charge state of the ignition capacitor may be known or defined, allowing subsequent sparks to be controlled as needed, i.e., starting from the known charge state of the ignition capacitor. This can be particularly useful for controlling the spark duration.

[0061] Figure 8 Another exemplary electronic circuit 101 is shown. In addition... Figure 5 In addition to electronic circuit 101, Figure 8 Another electronic circuit 101 also includes a storage capacitor C2 connected to the first power supply terminal TS1 and the second switch SW2. It should be noted here that the ignition capacitor C1 and the storage capacitor C2 can be referred to as the first capacitor C1 and the second capacitor C2, respectively. This means that the terms "ignition" and "storage" are used only as labels to distinguish the individual capacitors in this context.

[0062] also, Figure 8The electronic circuit 101 also includes a sixth switch SW6 connected to the second power supply terminal TS2 and the storage capacitor C2. The second switch SW2 is indirectly connected to the second power supply terminal TS2 through the sixth switch SW6.

[0063] In some examples, a capacitor discharge ignition system 100 is provided, which includes electronic circuitry 101 as described in any of the embodiments of this patent application.

[0064] Because there are two switches, SW2 and SW3, energy can be supplied to C1 in each cycle of the resonant ignition circuit, thereby maintaining the amplitude (magnitude) of the spark current or mitigating its decrease, thus maintaining the required energy in the spark to achieve strong ignition of the air-fuel mixture. This is accomplished by keeping one of the switches SW2 / SW3 closed at any given time. When the primary current > 0, SW3 can be opened and SW2 closed for a period of time until the supplied energy is sufficient to sustain the spark.

[0065] The energy supplied to the CDI system is: E = ∫V1 × I × dt. To maintain the spark current amplitude at or above the desired level, this energy can preferably be greater than the total energy consumed during the final cycle of the resonant ignition circuit. (Different expressions are possible.)

[0066] E>Ep+Es+Espark, where

[0067] • Ep is the loss in the primary coil. Ep depends on Ip (primary current) and can be made into a table or calculated.

[0068] Es is the loss in the secondary coil. Es depends on Is (secondary current) and can be tabled or calculated.

[0069] • Espark is the energy in the spark. Espark depends on Is (spark current) and the voltage across the gap.

[0070] according to Figure 8 Switch SW6, capacitor C2, and switch SW5 have been added. Figure 5 The circuit. In this way, electronic circuit 101 can change the voltage used to maintain and interrupt the spark.

[0071] For example, Figure 8 The attached figures are labeled with reference to the figures.

[0072] name describe 130 voltage source SW1 The first switch (one switch per coil when used in a multi-cylinder engine) SW2 Second switch SW3 Third switch SW4 Fourth switch SW5 Fifth Switch SW6 Sixth Switch C1 Capacitor discharge series capacitor C2 Storage capacitors L1 primary coil L2 Secondary coil SP1 spark plug 120 Control unit configured for measuring and controlling switches

[0073] The following shows an example of a method for setting a switch to control spark characteristics such as duration, spark voltage, and spark current (or secondary current).

[0074]

[0075] The control unit 120 can control the switch based on the measurement of the oscillating secondary current. This means that the control unit 120 can be configured to measure the secondary current. In other examples, the control unit 120 can be configured to control the switch based on the measurement of the oscillating primary current. As used in this patent application, the primary current refers to the current through the primary coil, and the secondary current refers to the current through the secondary coil.

[0076] The voltage across the energy storage capacitor C1 is shown in red in the diagram above. When the voltage across the spark plug required to generate a spark (flashover) is increased, some of the energy stored in the capacitor is lost.

[0077] Some of the energy stored in the capacitor is lost to maintain the spark and drive current through SW1 and the ignition coil (magnetic and resistive losses) as well as the (spark) plasma.

[0078] This causes the peak capacitor voltage (charge, energy) to decrease continuously, and the voltage-time domain (positive, negative, positive, etc.) of the capacitor to decrease continuously. This means that the current time domain on both the primary and secondary sides also decreases.

[0079] If we want to maintain a constant AC spark current for a longer period of time, or adjust the spark current amplitude, this can be done by adding a time-dependent voltage source V2 (see...). Figure 9 This is achieved by adding energy to the system. Control unit 120 can be configured to control the voltage output from time-dependent voltage source V2. Therefore, due to appropriate control signaling and circuitry for implementing the time-dependent voltage, control unit 120 can make the voltage from voltage source V2 time-dependent. In one example, Figure 9 Electronic circuit 101 can be equipped with... Figure 8 The fifth switch SW5 is connected similarly as shown. In some examples, the voltage source V2 may not need to be time-dependent.

[0080] Figure 9 The advantage of electronic circuit 101 is that the switch can be specified to have a higher... Figure 8 In the example, a lower voltage requirement.

[0081] Turning to Figures 10a through 10d, the principles behind a method, for example, executed by control unit 120, are described, which is used to control at least one spark characteristic, such as ignition voltage, spark current, and spark duration.

[0082] In Figure 10a, the voltage across capacitor C1 is shown as a solid line, and the current through the primary coil PL1 is shown as a dotted line.

[0083] To maintain a constant spark current amplitude, a voltage-time domain can be added during each cycle p of the capacitor voltage, or during at least one of the negative and positive half-cycles. This can be achieved by adding a medium-high DC voltage in phase with the capacitor voltage during a standard time interval, a higher DC voltage during a shorter time interval, or a lower DC voltage during a longer time interval, as shown in Figure 10b. In this case, alternating polarity voltages are used. This can be generated using a DC voltage source combined with four switches in an H-bridge (full-bridge) configuration. The height h and width d can be varied to increase the desired energy level WL, which is proportional to h*w.

[0084] In Figure 10c, the voltage-time domain is added only when the capacitor voltage is negative. This is a simpler approach, as it can sustain the spark current using only two half-bridge switches supplied by a single DC voltage source.

[0085] In Figure 10d, a time-varying voltage source is also used to generate a spark. By doing so, capacitor C1 does not need to be charged to the same level as in the previous example (e.g., in...). Figure 4 , Figure 5 or Figure 8 It can operate at the same high voltage as in other circuits. Therefore, the cost of electronic circuit 101 can be reduced.

[0086] CDI systems are typically powered by a 12V or 24V supply, such as an adjustable voltage source 130. The capacitors are usually charged to voltages between 200V and 400V.

[0087] The voltage required to sustain a spark for an extended or indefinite period is far less than 200V-400V. Typically, a voltage in the range of 24V-100V can be used for this purpose.

[0088] If a low voltage, such as 24V, can be used in conjunction with a full-bridge circuit to add 24V to a capacitor C1 with different polarities, a very energy-efficient system can be created because no additional voltage conversion is required between 24V and higher voltages, such as the previously mentioned 200V-400V. This translates to a significant reduction in cost.

[0089] Furthermore, if a voltage higher than 24V is used, but within the 24V-100V range, the system can be designed with lower cost and lower losses compared to a system using only one energy source with 200V-400V.

[0090] If only one voltage source V is used to charge capacitor C1 and generate a time-varying voltage source V2, this voltage source can be reduced from the usual 200V-400V to 100V-200V, which also simplifies the design of the CDI system. This can be done by connecting the voltage source V2 = V to the left side of the capacitor C1 being charged to voltage V (see [link to CDI system design]). Figure 5 This means that a voltage of 2V is shorted to the primary side of the ignition coil to generate a spark.

[0091] As shown in Figures 10b to 10d, energy is added during at least a portion of the time period so that the integral reaches the desired setpoint. This allows for individual control of each of the following: ignition voltage (if energy is added during the "first" time period), spark duration, and spark current.

[0092] If it is necessary to increase the spark current without extending the duration, energy of the opposite phase can be inserted to suppress oscillations more quickly. Therefore, the duration and spark current can be controlled independently.

[0093] Figure 11 An internal combustion engine 150 is shown, including an exemplary ignition system 100 according to an embodiment of this patent application. The ignition system 100 may be a CDI system, a CDI control system, etc.

[0094] As used in this patent application, the terms “first,” “second,” “third,” etc., may be used only to distinguish features, devices, elements, units, etc. from one another, unless otherwise apparent from the context.

[0095] As used in this patent application, the term "set" can refer to one or more of something. For example, according to embodiments of this patent application, a set of devices can refer to one or more devices, a set of parameters can refer to one or more parameters, etc.

[0096] As used in this patent application, the phrase "in some embodiments" has been used to indicate that features of the described embodiments may be combined with any other embodiments disclosed in this patent application when technically feasible.

[0097] Where physically possible, each embodiment, example, or feature disclosed in this patent application may be combined with one or more other embodiments, examples, or features disclosed in this patent application. Furthermore, many different changes, modifications, etc., of the embodiments of this patent application may become apparent to those skilled in the art. Therefore, the described embodiments are not intended to limit the scope of this patent application disclosure.

Claims

1. An electronic circuit (101) for controlling the spark of a spark plug (SP1) in a capacitor discharge ignition system (100) of an internal combustion engine, wherein, The electronic circuit (101) includes: An ignition coil (110) is provided, the ignition coil being arranged to supply current to the spark plug (SP1), wherein the ignition coil (110) includes a primary winding (L1) and a secondary winding (L2), the primary winding having a first primary terminal (TL1) and a second primary terminal (TL2), and the spark plug (SP1) being connectable to the secondary winding. An ignition capacitor (C1) is arranged to supply energy to the primary winding (L1), wherein the ignition capacitor (C1) has a first capacitor terminal (TC1) and a second capacitor terminal (TC2), wherein the first capacitor terminal (TC1) is connected to the second primary terminal (TL2). A voltage source (130) is arranged to supply energy to at least one of the ignition capacitor (C1) and the primary winding (L1), wherein the voltage source (130) has a first power supply terminal (TS1) and a second power supply terminal (TS2). The first switch (SW1) is connected to the first primary terminal (TL1) and the first power terminal (TS1). The second switch (SW2) is connected to the second capacitor terminal (TC2) and the second power supply terminal (TS2). The third switch (SW3) is connected to the second capacitor terminal (TC2) and the first power supply terminal (TS1). The first switch (SW1), the second switch (SW2), and the third switch (SW3) are arranged to supply energy to the capacitor (C1) in each cycle of the resonant ignition circuit consisting of the ignition capacitor (C1) and the primary winding (L1), thereby maintaining the amplitude of the spark current or slowing its decrease.

2. The electronic circuit (101) according to claim 1, wherein, The electronic circuit (101) includes The fourth switch (SW4) is connected to the second primary terminal (TL2) and the second power terminal (TS2).

3. The electronic circuit (101) according to claim 1 or 2, wherein, The electronic circuit (101) includes The fifth switch (SW5) is connected to the first capacitor terminal (TC1) and the first power supply terminal (TS1).

4. The electronic circuit (101) according to any one of claims 1-3, wherein, The electronic circuit (101) includes Storage capacitor (C2), the storage capacitor being connected to the first power supply terminal (TS1) and the second switch (SW2), and A sixth switch (SW6) is connected to the second power supply terminal (TS2) and the storage capacitor (C2), wherein the second switch (SW2) is indirectly connected to the second power supply terminal (TS2) via the sixth switch (SW6), and the sixth switch is connected to the second switch (SW2).

5. The electronic circuit (101) according to any one of claims 1-4, wherein, The electronic circuit (101) includes a control unit (120).

6. A capacitor discharge ignition system (100) comprising an electronic circuit (101) according to any one of claims 1-5.

7. An internal combustion engine comprising the capacitor discharge ignition system (100) according to claim 6.

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