Ignition coil assembly with internal diagnostic functions

Abstract

An ignition coil assembly with internal diagnostic features that can be used to monitor and evaluate various aspects of an ignition system and provide continuous feedback. The ignition coil assembly can be a coil-on-plug type device that converts low-voltage battery current into high-voltage ignition pulses, and it can include multiple input terminals, an ignition coil with primary and secondary windings, an ignition circuit, an output terminal, a spark plug connector, and a housing.The ignition circuit includes an ignition operating circuit and an ignition diagnostic circuit, which in turn includes a charge evaluation circuit for monitoring a charging phase, a discharge evaluation circuit for monitoring a discharge phase, and a feedback integration circuit for combining outputs into a multiplexed digital signal, which can then be sent via a single output connection to an engine control unit (ECU) or the like.

Description

AREA

[0001] The present disclosure relates generally to ignition coil arrangements for use in internal combustion engines and in particular to ignition coil arrangements with internal diagnostic functions that can be used to monitor and evaluate various aspects of an ignition system. BACKGROUND

[0002] The performance of an internal combustion engine can be affected by various aspects of and conditions within its ignition system, which can change over the engine's operating life. For example, a spark plug can become fouled due to oil, water, and / or other residues in the combustion chamber, and this fouling can cause a layer of deposits to form on one end of the spark plug, where a spark gap is located. Over time, this deposit layer, which is conductive to some extent, can build up to the point where it creates an alternative spark gap, suppressing an intended spark and / or short-circuiting an intended spark gap. This can cause a range of problems, from poor fuel economy and reduced engine power to rough idling and misfires.

[0003] Some conventional internal combustion engines have diagnostic functions that monitor various aspects of the ignition system. For example, there are well-known ignition systems that include diagnostic functions to monitor the charging or discharging phase of the ignition coil. However, these often only provide a diagnostic signal when a fault or malfunction (e.g., misfire) is detected, rather than providing continuous feedback that the engine can use to improve performance. Other well-known ignition systems may have diagnostic functions that provide more continuous types of feedback, but these are often limited to the input side (i.e., the primary winding), the output side (i.e., the secondary winding), the spark plug, or another limited part of the ignition system.Such diagnostic features do not necessarily provide a complete picture of the ignition system, specifically regarding the input, output, and spark plug on a continuous basis. One example of a well-known ignition system diagnostic feature is an ion current sensor, which, after a sparking process, applies a small voltage to a spark gap and then measures the ionization current and its behavior over time. These measurements are typically provided to the engine as an analog signal and can indicate the presence of a dirty or worn spark plug, but they provide little information about the input and output sides of the ignition system. Furthermore, these types of analog signals generally have very low signal strength and are more susceptible to electromagnetic (EM) noise in the ignition system.

[0004] One objective of the present application is therefore to provide an ignition coil assembly with internal diagnostic features that address some of the disadvantages of known ignition systems described above. SUMMARY

[0005] According to one embodiment, an ignition coil arrangement for use in an ignition system is provided, comprising: a plurality of input terminals; an output terminal; an ignition coil with a primary winding and a secondary winding;and an ignition circuit comprising an ignition operating circuit and an ignition diagnostic circuit, wherein the ignition operating circuit is configured to control the charging and discharging of the ignition coil and is connected to at least some of the input terminals and the ignition coil, wherein the ignition diagnostic circuit is configured to monitor various aspects of the ignition system and is connected to the ignition coil and the output terminal, wherein the ignition diagnostic circuit is configured to provide continuous feedback to the ignition system by sending a diagnostic signal via the output terminal, the diagnostic signal containing information representative of both a charging phase and a discharging phase.

[0006] In accordance with the various embodiments, the ignition coil arrangement may have one or more of the following features, either individually or in any technically possible combination: - the plurality of input terminals comprises a first low-voltage input terminal configured to receive low-voltage battery current from a battery, a second low-voltage input terminal configured to receive a trigger signal from an engine control unit (ECU), a third low-voltage input terminal configured to receive battery ground, and a fourth low-voltage input terminal configured to receive engine ground, wherein the plurality of input terminals and the output terminal are part of a unified multi-pin electrical connector; - The multiple input terminals include a low-voltage input terminal configured to receive battery ground and a separate low-voltage input terminal configured to receive engine ground, with the battery ground and engine ground being electrically isolated from each other so that the diagnostic signal is more immune to internal noise; - The ignition operating circuit comprises a driver circuit and a switch, wherein the driver circuit has an input configured to receive trigger signals from an engine control unit (ECU) and an output configured to supply trigger signals to the switch, wherein the switch is an insulated-gate bipolar transistor (IGBT) and has a first terminal connected to the primary winding of the ignition coil, a second terminal connected to the output of the driver circuit configured to receive trigger signals, and a third terminal connected to the ignition diagnostic circuit, and wherein the ignition operating circuit is configured such that the trigger signals cause the switch to be either 'on', allowing charging current to flow through the primary winding, or 'off', allowing no charging current to flow through the primary winding; - the ignition diagnostic circuit includes a charge evaluation circuit coupled to the primary winding, a discharge evaluation circuit coupled to the secondary winding, and a feedback integration circuit coupled to the charge evaluation circuit, the discharge evaluation circuit, and the output terminal; - The charge evaluation circuit includes a resistor, an operational amplifier, and a charge evaluation output. The resistor is connected in series with the primary winding in a charge path, with the operational amplifier having a first input connected to one terminal of the resistor and a second input connected to a reference voltage (V). REF) is connected, and an output connected to the charge evaluation output, wherein the charge evaluation output is connected to the feedback integration circuit, wherein the charge evaluation circuit is configured to output an active charge signal when a charge current flowing through the charge path exceeds a charge current threshold, and wherein the charge evaluation circuit is configured to output an inactive charge signal when the charge current flowing through the charge path does not exceed the charge current threshold, and wherein the charge current threshold is at least partially determined by the reference voltage (V REF ) is determined; - The charge evaluation circuit is configured to output an active charge signal to the feedback integration circuit when a charge current flowing through a charge path is greater than a charge current threshold, wherein the feedback integration circuit is configured to combine the active charge signal with the output signal from the discharge evaluation circuit to generate the diagnostic signal, wherein the diagnostic signal contains a rising edge or a falling edge (t1) that is representative of the active charge signal and can be used in conjunction with a separate trigger signal (t0) to determine a charge duration (t1-t0), wherein the charge duration corresponds to a time period required for the charge current to exceed the charge current threshold, and wherein the charge duration is representative of a state or condition of the primary winding; - The discharge evaluation circuit comprises an opto-isolator with a light-emitting device and a light-activated switch, a resistor, and a discharge evaluation output, wherein the light-emitting device is connected in series with the secondary winding in a discharge path, wherein the light-activated switch is operationally coupled to the light-emitting device and includes a terminal connected to a terminal of the resistor, wherein the discharge evaluation output is connected to the feedback integration circuit, wherein the discharge evaluation circuit is configured to output an active discharge signal when a discharge current flowing through the discharge path exceeds a discharge current threshold, and wherein the discharge evaluation circuit is configured to output an inactive discharge signal.if the discharge current flowing through the discharge path does not exceed the discharge current threshold, and wherein the discharge current threshold is at least partially determined by properties of the light-emitting device and / or the light-activated switch; - The discharge evaluation circuit is configured to output an active discharge signal to the feedback integration circuit when a discharge current flowing through a discharge path is less than a discharge current threshold, wherein the feedback integration circuit is configured to combine the active discharge signal with the output signal from the charge evaluation circuit to generate the diagnostic signal, wherein the diagnostic signal contains a rising edge or a falling edge (t3) that is representative of the active discharge signal and can be used in conjunction with a separate trigger signal (t2) to determine a discharge duration (t3 - t2), wherein the discharge duration corresponds to a time period required for the discharge current to fall below the discharge current threshold, and wherein the discharge duration is representative of a state or condition of the secondary winding or a corresponding spark plug;- The feedback integration circuit comprises a logic gate and a switch, wherein the logic gate has a first input connected to a charge evaluation output of the charge evaluation circuit and configured to receive a charge signal, a second input connected to a discharge evaluation output of the discharge evaluation circuit and configured to receive a discharge signal, and an output configured to provide a combined charge and discharge signal, wherein the switch has a first terminal connected to the output terminal and a second terminal connected to the output of the logic gate and configured to receive the combined charge and discharge signal, and wherein the feedback integration circuit is configured to use the combined charge and discharge signal to output the diagnostic signal via the output terminal; and - the diagnostic signal contains information that is representative of both a charging signal generated during the charging phase and a discharging signal generated during the discharging phase, and wherein the ignition circuit is configured to combine the charging signal and the discharging signal into the diagnostic signal and to provide the combined diagnostic signal via the output terminal, which is a single pin in a multi-pin electrical connector.

[0007] According to another embodiment, a method for operating an ignition coil assembly for use in an ignition system is provided, wherein the ignition coil assembly comprises: a plurality of input terminals; an output terminal; an ignition coil with a primary winding and a secondary winding; and an ignition circuit with an ignition operating circuit and an ignition diagnostic circuit; wherein the method comprises the following steps: managing the charging and discharging of the ignition coil with the ignition operating circuit; monitoring various aspects of the ignition system with the ignition diagnostic circuit; and providing continuous feedback from the ignition diagnostic circuit to the ignition system by sending a diagnostic signal via the output terminal, wherein the diagnostic signal contains information representative of both a charging phase and a discharging phase.

[0008] According to the various embodiments, the method for operating an ignition coil assembly may have one or more of the following features, either individually or in any technically possible combination: - The monitoring step further involves monitoring a charging current flowing through a charging path containing the primary winding, a switch, and a resistor, and using an operational amplifier to generate a voltage across one terminal of the resistor with a threshold voltage V REF to compare and output an active charging signal when the voltage exceeds the threshold voltage, indicating that the charging current has exceeded a charging current threshold; - the step of providing continuous feedback further comprises sending a diagnostic signal that combines an active charging signal from a charging evaluation circuit with an output from a discharging evaluation circuit, wherein the diagnostic signal contains a rising edge or a falling edge (t1) that is representative of the active charging signal, and wherein the step further comprises the following steps: evaluating the diagnostic signal in an engine control unit (ECU) in conjunction with a separate trigger signal (t0) to determine a charging duration (t1-t0), wherein the charging duration corresponds to a time period required by a charging current flowing through a charging path containing the primary winding to reach a charging current threshold, and determining a state or condition of the primary winding based on the charging duration; - the monitoring step further includes monitoring a discharge current flowing through a discharge path containing the secondary winding and a current evaluator with a light-emitting device and a light-activated switch, terminating light emission from the light-emitting device when the discharge current flowing through the discharge path does not exceed a discharge current threshold, "switching off" the light-activated switch when the light-emitting device stops emitting light, and outputting an active discharge signal when the light-activated switch is "off", indicating that the discharge current has fallen below the discharge current threshold; - the step of providing continuous feedback further comprises sending a diagnostic signal that combines an active discharge signal from a discharge evaluation circuit with an output from a charge evaluation circuit, wherein the diagnostic signal contains a rising edge or a falling edge (t3) that is representative of the active discharge signal, and wherein the step further comprises the following steps: evaluating the diagnostic signal at an engine control unit (ECU) in conjunction with a separate trigger signal (t2) to determine a discharge duration (t3 - t2), wherein the discharge duration corresponds to a time period required for a discharge current flowing through a discharge path containing the secondary winding to fall below a discharge current threshold, and determining a state or condition of the secondary winding or a corresponding spark plug based on the discharge duration; - the step of providing continuous feedback further includes sending a multiplexed digital diagnostic signal containing information from an active charging signal from a charging evaluation circuit and information from an active discharging signal from a discharging evaluation circuit, the multiplexed digital signal being sent via a single output terminal; - The multiple input terminals include a low-voltage input terminal configured to receive battery ground and a separate low-voltage input terminal configured to receive engine ground, with the battery ground and engine ground being electrically isolated from each other so that the diagnostic signal is more immune to internal noise; and - further comprising the step of receiving the diagnostic signal at an engine control unit (ECU) that is part of the ignition system for an engine that burns hydrogen fuel, and using the diagnostic signal to determine if the hydrogen combustion engine has experienced any combustion failures. DRAWINGS

[0009] Preferred embodiments are described below in conjunction with the accompanying drawings, where identical designations denote identical elements and where: Fig. 1 is a schematic representation of an exemplary ignition system; Fig. 2 is a perspective view of an exemplary ignition coil arrangement, which is connected to the ignition system of Fig. 1 can be used; Fig. 3 a schematic representation of the ignition coil arrangement of Fig. 2 is; Fig. 4 a circuit diagram of the ignition coil arrangement of Fig. 2 is; and Fig. 5 is a time diagram of several exemplary waveforms and signals used in a method for operating an ignition system, such as the one described in Fig. 1 shown, could be used. DESCRIPTION

[0010] The ignition coil arrangement described here has internal diagnostic features that can be used for the continuous monitoring and evaluation of various aspects of an ignition system and its operation, as will be described below. With reference to Fig. Figure 1 is a schematic diagram of an exemplary ignition system 10 for use with a four-cylinder internal combustion engine, wherein the ignition system is a coil-on-plug type ignition system. The ignition system 10 may include a battery 12, ignition coil assemblies 14-20, spark plugs 22-28, an engine control unit (ECU) 30, and any number of other components, devices, and / or units known in the art. As the name suggests, the ignition system 10 has a separate ignition coil assembly 14-20 mounted on each spark plug 22-28, so that each spark plug is directly ignited by a specific, dedicated ignition coil. Experts know that while coil-on-plug ignition systems offer a number of advantages over conventional ignition systems, such as distributorless systems, they can sometimes be more difficult to diagnose.Accordingly, each ignition coil assembly 14-20 is equipped with internal diagnostic functions that continuously monitor various aspects of the ignition system and send feedback to the ECU 30 via digital diagnostic signals containing information for evaluating the input side, the output side, the spark plug, and / or other aspects of the ignition system. The digital diagnostic signals can contain information about the elapsed time between different ignition events, as well as other information. In the illustrated embodiment, a digital diagnostic signal is sent from each ignition coil assembly 14-20 to the ECU 30 via a separate line or connection. However, it is also possible to connect the output terminals 66 of several ignition coil assemblies 14-20 together, so that multiple diagnostic signals 330 are sent to the ECU 30 via a single line or connection.Since the different cylinders fire at different times, the information in the various diagnostic signals could be extracted separately and processed by the ECU 30 on a time basis determined by the system's ignition timing, even though all information is transmitted via a single wire or connection. Such an embodiment would allow the ignition system 10 to comprehensively monitor all ignition coil assemblies 14-20 and / or spark plugs 22-28 via a single input and / or a single wire to the ECU 30. It is also possible for the present ignition coil assembly to be used with systems in which the ignition coils are not attached to the spark plug and are connected to the corresponding spark plugs via high-voltage cables.

[0011] It should be noted that the ignition coil arrangements described here can be used with a wide variety of engines and are not limited to the examples described below or shown in the drawings.For example, the ignition coil assemblies presented here can be used with internal combustion engines that burn gasoline, diesel, natural gas, hydrogen, propane, biodiesel, ethanol and / or other types of combustible fuels; internal combustion engines used in cars, sport utility vehicles (SUVs), hybrid vehicles, light trucks, medium trucks, heavy trucks, semi-trailer trucks, buses, boats, aircraft, trains, construction equipment, mining equipment, tractors, generators, industrial engines and / or other types of automotive and industrial applications; in internal combustion engines with any number of cylinders, including more or fewer than four cylinders; and in internal combustion engines that operate with port fuel injection (PFI), gasoline direct injection (GDI), electronic fuel injection (EFI) and / or other types of fuel injection, to name just a few possibilities.The ignition coil arrangements described here can be used with any type of engine that uses a spark to ignite a combustible fuel.

[0012] The battery 12 supplies the ignition system 10 with low-voltage battery power and can be any suitable battery type known in the art. For example, the battery 12 can be a standard rechargeable lead-acid DC battery with 12 V or 24 V, although other battery types can also be used. The battery 12 has a negative terminal 40, which is connected to the battery ground (e.g., the vehicle chassis), and a positive terminal 42, which is connected to each of the ignition coil assemblies 14-20 and to the ECU 30. The positive terminal 42 preferably supplies each of the ignition coil assemblies 14-20 with low-voltage battery power (e.g., 12 V-24 V DC).

[0013] The ignition coil assemblies 14-20 convert low-voltage battery power into high-voltage ignition pulses, which are supplied to the spark plugs 22-28 to initiate the combustion process. The ignition coil assemblies 14-20 can incorporate any suitable type of automotive or industrial ignition coil known in the art, including various types of coil-on-plug and other ignition coils. For the sake of simplicity, the following description is given in connection with the ignition coil assembly 14 and the spark plug 22; however, this description applies equally to the other ignition coil assemblies 16-20 and the spark plugs 24-28 (duplicate descriptions have been omitted). As in the Fig. As best illustrated in 2-4, the ignition coil assembly 14 generally has several input terminals 50-56, an ignition coil 58 with primary and secondary windings 60 and 62, an ignition circuit 64, an output terminal 66, a spark plug connector 68 and a housing 70.

[0014] Input terminals 50-56 are electrical connections that supply the ignition coil assembly 14 with power, ground, control signals, and / or other low-voltage inputs required for operation. For example, input terminal 50 can be a low-voltage pin that, when connected, is connected to the positive terminal 42 of battery 12 and receives low-voltage battery power. Input terminal 52 can be a low-voltage pin that, when connected, is connected to an output terminal of the ECU 30 and receives a trigger signal that causes the spark plug 22 to fire at a timing specified by the ECU. Input terminals 54 and 56 can be low-voltage pins connected to battery ground (e.g., the negative terminal 40 of the battery) and engine ground, respectively.The electrical isolation of the battery ground 54, sometimes also referred to as control unit ground or chassis ground, from the engine ground 56 helps to give the diagnostic signals a certain degree of immunity to internal noise generated by the ignition system and / or the internal combustion engine during operation, particularly during spark plug firing. The input terminals 50-56 and the output terminal 66 are in . Fig. 2 is shown as part of a unified five-pin electrical connector 80, which is located on one side of the housing 70. The electrical connector 80 is designed to be connected to a wiring harness or a complementary electrical connector of any type, which connects the ignition coil assembly 14 to the battery 12, the ECU 30, the engine ground, and / or other devices within the ignition system or the internal combustion engine. However, it is entirely possible for the input and / or output terminals to be arranged in a different configuration.

[0015] The ignition coil 58 is a transformer having primary and secondary windings 60, 62, and is responsible for converting low-voltage battery power into high-voltage ignition pulses, which are then supplied to the spark plug 22. According to the Fig. In the example shown, a first terminal of the primary winding 60 is connected to the input terminal 50 and receives low-voltage battery power, while a second terminal of the primary winding 60 is connected to a switch 84, which is part of the ignition circuit 64. When the switch 84 is opened, allowing electric current to flow through the primary winding 60, an electromagnetic field is induced in the ignition coil 58, and also in the secondary winding 62. When the switch 84 is opened and the electric current abruptly ceases to flow through the primary winding 60, the electromagnetic field collapses suddenly and induces a high-voltage ignition pulse in the secondary winding 62. The high-voltage ignition pulse, which can be in the range of 5–50 kV or more, is then conducted from the secondary winding 62 to the spark plug connector 68, which fits over and is electrically connected to a terminal 86 of the spark plug 22.In the example of a non-coil-on-plug system, the high-voltage ignition pulse would be conducted from the secondary winding to the spark plug via a high-voltage cable. From there, the high-voltage ignition pulse travels within the spark plug 22 from the terminal end 86 to an ignition end 88, where it creates an arc across a spark gap 90 and ignites an air-fuel mixture in a combustion chamber to initiate the combustion process. According to a non-restrictive example, the primary winding 60 has 50–500 wire turns and the secondary winding 62 has 5,000–50,000 wire turns (e.g., 100 times more than the primary winding), and both windings are wound around a ferromagnetic core 92.

[0016] The ignition circuit 64 is responsible for charging / discharging the ignition coil 58 according to the desired ignition timing of the ignition system, as well as for providing feedback to the ignition system in the form of diagnostic signals. According to the Fig. In the example shown in Figure 4, the ignition circuit 64 comprises an ignition operating circuit 100 and an ignition diagnostic circuit 102. The ignition operating circuit 100 manages aspects of the charging and discharging of the ignition coil 58 and may include a voltage regulator 110, a switch 84, a driver circuit 112, and other suitable electronic components, units, circuits, and / or other devices known in the art. The voltage regulator 110 is a DC voltage regulator that has an input 120 connected to the low-voltage battery power supply and an output 122 that supplies the ignition circuit 64 with regulated low-voltage DC power (V10). DD) supplied, and has an input 124 connected to battery ground 54. According to an example, the voltage regulator 110 is a low-dropout regulator (LDO) that can operate even when the supply voltage (low-voltage battery power) is very close to the output voltage (V). DDThe switch 84 is a power transistor with a collector terminal 130 connected to the primary winding 60, a gate terminal 132 connected to an output of the driver circuit 112, and an emitter terminal 134 connected to the ignition diagnostic circuit 102, as explained below. In one example, the switch 84 is a high-power insulated-gate bipolar transistor (IGBT) controlled by trigger signals from the ECU 30. The driver circuit 112 regulates the gate current for the switch 84 and has an input 140 connected to the low voltage battery power, an input 142 connected to the ECU 30 to receive trigger signals, an input 144 connected to the ignition diagnostic circuit 102, an output 146 connected to the gate terminal 132 of the switch 84, and an input 148 connected to the battery ground 54.The driver circuit 112 acts as a kind of interface between the ECU 30 and the circuit breaker 84. The term "trip signal" used here encompasses, in the broadest sense, all electronic signals that serve to control the operating state of the switch 84, including trip signals sent directly from the ECU 30 to the switch 84 and trip signals sent indirectly from the ECU 30 to the switch 84 via the driver circuit 112 and / or other electronic devices.

[0017] The ignition diagnostic circuit 102 monitors various aspects of the ignition system, provides continuous feedback to the ignition system in the form of diagnostic signals, and may include a charge evaluation circuit 160, a discharge evaluation circuit 162, a feedback integration circuit 164, and other suitable electronic components, units, circuits, and / or other devices known in the art. As the name suggests, the charge evaluation circuit 160 evaluates various aspects of the charging phase and includes a resistor 170, an operational amplifier 172, battery ground 54, and a voltage 174. The resistor 170 is connected in series with the primary winding 60, so that it is in a charging path, and has a first terminal 176 connected to the switch 84 and a second terminal 178 connected to the battery ground 54.In one example, resistor 170 has a resistance between 5 mΩ and 25 mΩ, but this is not required. Operational amplifier 172 is preferably a current-feedback operational amplifier that compares the voltages measured at its non-inverting input 182 and its inverting input 184 and, based on this comparison, provides an output signal at output 186. The non-inverting input 182 is a high-impedance input connected to the first terminal 176 of resistor 170, and the inverting input 184 is a high-impedance input connected to a reference voltage (Vr). REF), e.g., the battery ground 54. The charge evaluation output 174, connected to the output of the operational amplifier 172, serves as the output for the charge evaluation circuit 160 and supplies the feedback integration circuit 164 with either an active or an inactive charge signal, depending on the output of the operational amplifier. It should be noted that the charge evaluation circuit 160 may be arranged differently than the one shown in Fig. 4. Exemplary embodiment shown, provided it is configured to output an active charging signal when the charging current 300 flowing through the charging path exceeds a charging current threshold, and an inactive charging signal when the charging current does not exceed the charging current threshold. For example, the non-inverting and inverting inputs 182, 184 could be switched such that the output of the operational amplifier is switched; the inverting input 184 could be connected to the second terminal 178 of resistor 170 such that the reference voltage (V REF ) the battery mass is 54, in contrast to a certain V REF -value; and the order or arrangement of the primary winding 60, the switch 84, the resistor 170 and / or the battery ground 54 in the charging path could be changed, to name just a few possibilities.

[0018] The discharge evaluation circuit 162 evaluates various aspects of the discharge phase and includes a current evaluator 190, a resistor 220, a discharge evaluation output 222, and the motor ground 56. The current evaluator 190 is connected in series with the secondary winding 62, so that it is in a discharge path together with the motor ground 56. For example, the current evaluator 190 is an opto-isolator comprising a light-emitting device 192 and a light-activated switch 194, and it can transmit signals between two electrically isolated circuits, such as the circuits comprising the battery ground 54 and the motor ground 56. Another possibility for the current evaluator 190 is an isolated operational amplifier; however, these devices are generally quite expensive. The light-emitting device 192 can be an LED, the first terminal of which 196 (e.g.The anode of the LED is connected to the secondary winding 62, and its second terminal 198 (e.g., a cathode) is connected to the motor ground 56. The LED is functionally coupled to the light-activated switch 194, so that the LED emits light towards the light-activated switch 194 when the discharge current flowing through the LED exceeds a discharge current threshold. The discharge current threshold is determined, at least in part, by the characteristics of the light-activated device and / or the switch (the more sensitive the devices, the lower the threshold) and should be as close to zero as possible, while still providing some immunity to disturbances in the system. The light-activated switch 194, which may be a phototransistor, a photodiode, or the like, may have collector, base, and emitter terminals 210, 212, and 214, respectively.When sufficient light is registered by the LED 192 at the base terminal 212, the light-activated switch 194 turns on and current flows from V. DD via resistor 220, switch 194, and motor ground 56. This results in a voltage drop at the discharge evaluation output 222, which is connected to the feedback integration circuit 164 and outputs an active discharge signal. The discharge evaluation output 222 serves as the output for the discharge evaluation circuit 162 and supplies the feedback integration circuit 164 with either an active or an inactive discharge signal. An optional resistor 230 can be connected in parallel with LED 192. It is possible that the discharge evaluation circuit 162 is configured differently than shown. Fig. 4 is arranged as long as it is configured to output an active discharge signal when the discharge current 310 flowing through the discharge path exceeds a discharge current threshold, and an inactive discharge signal when the discharge current does not exceed the discharge current threshold.

[0019] The feedback integration circuit 164 receives the outputs from the charging and discharging evaluation circuits 160 and 162 and combines these outputs into a single digital diagnostic signal, which can then be supplied to the ECU 30 and / or another device via a single output terminal 66. Combining these outputs into a single diagnostic signal, which can then be supplied via a single output terminal, provides the ignition coil assembly 14 with a very cost-effective way to continuously supply valuable feedback to the ignition system 10 and / or the corresponding engine. This can be particularly useful in internal combustion engines that burn hydrogen and / or certain other gases, as it is important for such engines to accurately monitor for missing combustion due to wear or other malfunctions of the ignition coils and / or spark plugs.Since the diagnostic signal is a digital signal, it is less susceptible to cycle-to-cycle reliability problems that commonly occur with analog signals, as these types of digital signals exhibit greater immunity to electromagnetic interference and the like. According to the [reference]... Fig. In the example shown in Figure 4, the feedback integration circuit 164 comprises a logic gate 240 (e.g., an OR gate) and a switch 242. The OR gate 240 has a first input 250, a second input 252, and an output 254. The first input 250 is connected to the charge evaluation output 174 so that it can receive the charge signal from the charge evaluation circuit 160; the second input 252 is connected to the discharge evaluation output 222 so that it can receive the discharge signal from the discharge evaluation circuit 162; and the output 254 is connected to the switch 242 so that it can provide a combined charge and discharge signal that controls the state of the switch. The switch 242 can be any suitable type of electronic switch, including a negative metal oxide semiconductor (NMOS) transistor or any other transistor type, and has drain, gate and source terminals 260, 262 and 264 respectively.In this specific configuration, the drain terminal 260 is connected to the output terminal 66 and provides the diagnostic signals, the gate terminal 262 is connected to the output 254 of the OR gate 240, and the source terminal 264 is connected to battery ground 54. It is possible to omit switch 242 in the feedback integration circuit 164 (e.g., the output of the OR gate 240 could simply be connected to output terminal 66, with or without signal conditioning) or to replace switch 242 with another component. The operation of the feedback integration circuit 164 is described in more detail below.

[0020] The spark plugs 22-28 can be any suitable type of automotive, industrial, and / or other ignition device. This includes, but is not limited to, ignition devices designed for the combustion of gasoline, diesel, natural gas, hydrogen, propane, biodiesel, ethanol, and / or other types of combustible fuels; ignition devices used in cars, sport utility vehicles (SUVs), hybrid vehicles, light, medium, and heavy-duty trucks, semi-trailer trucks, buses, boats, aircraft, trains, construction equipment, mining equipment, tractors, generators, industrial engines, and / or other applications; and ignition devices intended for use in various types of internal combustion engines, including naturally aspirated, turbocharged, and / or supercharged engines. The spark plugs 22-28 are not limited to any particular embodiment, as long as they can be used with the ignition coil assemblies 14-20.

[0021] The engine control unit (ECU) 30, sometimes also referred to as the engine control module (ECM) or even the powertrain control module (PCM), is an electronic device that controls various systems and / or functions related to an internal combustion engine, including certain aspects of the ignition system 10. According to one example, the ECU 30 has one or more microprocessors, microcontrollers, microcontroller units (MCUs), central processing units (CPUs), and / or other types of electronic processing devices, as well as various inputs and outputs. As in Fig. As shown in Figure 1, the ECU 30 may have one input 280 connected to battery 12 to receive battery power, one input 282 to receive battery ground, four inputs / outputs 284-290 connected to the ignition coil assemblies 14-20 to send trigger signals and receive diagnostic signals, and one optional input / output 292 for communication with a vehicle bus or other communication network. Experts will understand that the ECU 30 likely has numerous other components, devices, inputs, and / or outputs (e.g., inputs connected to various sensors around the engine, etc.), but these have been omitted here for simplicity.The ECU 30 preferably includes signal processing resources that enable it to evaluate and analyze the diagnostic signals supplied by the ignition coil assemblies 14-20, so that the ECU can better monitor and / or control various aspects of the ignition system 10. For example, the ECU 30 may use the diagnostic signals to better detect missed combustion or other malfunctions in the ignition coil and / or spark plugs, or to improve the ignition timing performance. It is also possible for the ECU 30 to monitor and / or control the ignition coil assemblies 14-20 on an individual basis, taking into account the conditions and circumstances unique to each assembly or spark plug. Of course, other arrangements are also possible, as the ECU 30 serves only as an example and can include any suitable type of control unit or module known in the art.

[0022] The terms "connected" and "coupled" as used here, in their broadest sense, encompass all suitable arrangements in which electrical inputs, outputs, terminals, components, devices, units, circuits, and / or other types of electrical elements are directly or indirectly connected or coupled to one another, including arrangements in which one electrical element is connected or coupled to another electrical element via one or more intervening electrical elements. For example, a switch terminal that is indirectly connected or coupled to an output via one or more intervening resistors, diodes, capacitors, inductors, transistors, etc., would still be "connected" or "coupled" to the output.

[0023] In Fig. Figure 5 shows several waveforms or timing diagrams representing different signals or currents used in the operation of the ignition system 10 (charging current 300, discharging current 310, trigger signal 320, diagnostic signal 330). Starting at time t0 (beginning of the charging phase), the ECU 30 sends the trigger signal 320 to the switch 84 via the driver circuit 112, which opens the switch so that the charging current 300 begins to flow through the primary winding 60 and charges the ignition coil 58. This is reflected in the diagrams, where a rising edge 320RE of the trigger signal corresponds to the beginning of a rising ramp 300RR of the charging current 300. At time t0, little to no charging current 300 flows through the charging path, i.e., the current path which has the primary winding 60, the switch 84, the resistor 170 and the battery ground 54.Therefore, there is only a small or no voltage drop across the resistor 170, so that the voltage at the terminal 182 of the operational amplifier 172 is lower than a threshold voltage V. REF, which is connected to the other terminal 184, causing the operational amplifier, and thus the output 174 of the charging evaluation circuit, to supply the feedback integration circuit 164 with an inactive charging signal. It should be noted that the ignition circuit 64 can be configured with positive logic, providing "active" signals which are "high" or "1" by default (e.g., standard transistor-to-transistor (TTL) voltage levels greater than a certain threshold (e.g., 2V) and down to the battery voltage) and "inactive" signals which are standard "low" or "0" voltage levels below a certain threshold (e.g., 2V) and down to battery ground. Alternatively, the ignition circuit could be configured with negative logic, where "active" signals are "low" or "0" and "inactive" signals are "high" or "1".Similarly, the ignition circuit 64 could be configured to replace rising edges with falling edges and vice versa, since it is not critical for the circuit to specifically use high-to-low or low-to-high transitions, as long as a transition occurs. Any of these arrangements is conceivable. The inactive charging signal causes the feedback integration circuit 164 to generate a diagnostic signal 330 with an active value, which is why the diagnostic signal starts with a high value at time t0.

[0024] From time t0 to time t1, the amount of charging current 300 flowing through the primary winding 60 continues to increase along the rising ramp 300RR. When the charging current 300 reaches a charging current threshold value 354 at time t1, the voltage drop across resistor 170 becomes so large that the voltage at the input 182 of operational amplifier 172 exceeds the threshold voltage V. REFexceeds the input voltage and converts the output of the operational amplifier into an active charging signal, which is then fed to the input 250 of the OR gate 240. This active or high input causes the OR gate 240 to output an active or high value at its output 254, which "turns on" the switch 242, so that its terminal 260 is connected to battery ground 54. The output terminal 66 accordingly provides an inactive or low signal. This transition from active to inactive or from high to low is represented by the falling edge 330FE in the diagnostic signal 330 at time t1. The charging time 350 (t1-t0) represents the time the charging current 300 took to reach a predetermined charging current threshold 354 (corresponding to V). REFto reach the charging current threshold 354 too quickly, and this information can be useful for analysis by the ECU 30. For example, if the charging current 300 reaches the charging current threshold 354 too quickly, so that the charging time 350 is less than a predetermined minimum time (i.e., (t1-t0) < Δt) 1MIN ), the ECU 30 can conclude that there is a short circuit in the primary winding 60. If the charging current 300 reaches the charging current threshold value 354 within an expected time period greater than the minimum value Δ t1MIN , but is smaller than a predetermined maximum time interval (i.e., Δ t1MIN < (t1-t0) < Δ t1MAX ), then the ECU 30 can determine that the primary winding 60 is functioning correctly. On the other hand, if the charging current 300 takes too long to reach the charging current threshold 354, so that the charging time 350 is greater than the maximum time span (i.e., (t1-t0) > Δ t1MAX), then this could indicate that the primary winding 60 has an unusually high impedance and is not functioning properly.

[0025] It is worth noting that the charging duration 350 is not the same as the dwell time, a more common parameter in ignition systems, which corresponds to the time the ignition coil is charged (e.g., the time switch 84 is "on"). The dwell time can be easily determined, as it simply corresponds to the duration of the trigger signal (the ECU would already have this information) and provides no meaningful feedback about the state of the primary winding 60. The charging duration 350, on the other hand, provides the ECU with valuable information about the state of the primary winding 60 via a digital multiplex signal that is representative of both the charging and discharging phases. The preceding examples represent only some of the ways in which the ECU 30 could use or evaluate the diagnostic signal 330, as numerous other possibilities are conceivable.

[0026] This charging process of the ignition coil 58 continues until the trigger signal 320 transitions from a high value to a low value at time t2 with the falling edge 320FE. This transition switches off the switch 84, thus preventing the charging current 300 from flowing in the charging path, as represented by the falling edge 300FE. The abrupt drop in the charging current 300 causes the magnetic field in the ignition coil 58 to collapse, resulting in a sudden flow of the discharge current 310 through the secondary winding 62, as represented by the falling edge 310FE (this is shown in Fig.(5 is shown as a falling edge, as opposed to a rising edge, due to the opposite winding direction of the secondary winding relative to the primary winding). The rapid flow of the discharge current 310 causes a high-voltage ignition pulse to be sent to the ignition end 88 of the spark plug 22, creating a spark at the spark gap 90 and initiating the combustion process. As the discharge current 310 flows in the discharge path, which includes the secondary winding 62, the current evaluator 190, and the motor ground 56, the current flow through the light-emitting device 192 causes it to emit light, which in turn activates the light-activated switch 194.Since the circuit containing the discharge path (motor ground) is separate and electrically isolated from the circuit containing the feedback integration circuit 164 (battery ground), a device such as an opto-isolator is used to bridge or transmit signals between them. When the light-activated switch 194 is turned on, the discharge evaluation circuit 162 outputs an active discharge signal, which is then fed to the input 252 of the OR gate 240. This active or high input causes the OR gate 240 to maintain an active or high value at its output 254, thus keeping the switch 242 "on" so that its terminal 260 remains connected to battery ground 54. Accordingly, the diagnostic signal 330 is held at a low value at time t2.The ignition coil 58 discharges its stored energy until it is used up and the discharge current 310 returns to its initial state, as can be seen from a rising ramp 310RR.

[0027] When the ignition coil 58 is fully or almost fully discharged at time t3, the discharge current 310 flowing through the discharge path decreases until the light-emitting device 192 no longer produces light and the light-activated switch 194 turns "off," causing the discharge evaluation circuit 162 to supply the feedback integration circuit 164 with a low or inactive discharge signal. Since both OR gate inputs 250 and 252 are low, output 254 is also low and turns off switch 242, thus disconnecting output terminal 66 from battery ground 54. This causes the diagnostic signal 330 to transition from inactive to active, or from low to high, on the rising edge 330RE corresponding to time t3.The discharge time 360 ​​(t3 - t2) represents the time required to discharge the charge stored in the ignition coil 58 and can be useful information for analyzing the ECU 30. For example, the discharge time 360 ​​can be an indicator of the secondary winding performance and / or the sparking power, as it correlates with the duration of the sparking process. If the discharge current 310 discharges too quickly, such that the discharge time 360 ​​is less than a predetermined minimum time (i.e., (t3 - t2) < Δ), the discharge time 360 ​​will be significantly reduced. t3MIN ), the ECU 30 can conclude that there is a short circuit in the secondary winding 62. If the discharge current 310 discharges in an expected time period that is greater than the minimum amount Δ t3MIN , but smaller than a predetermined maximum time interval (i.e., Δ t3MIN < (t3-t2) < Δt 3MAXIf the discharge current 310 takes too long to discharge (i.e., (t3 - t2) > Δ), then the ECU 30 can determine that the secondary winding 62 is functioning correctly. Conversely, if the discharge current 310 takes too long to discharge (i.e., (t3 - t2) > Δ t3MAX ), the ECU may conclude that there is an unacceptably high impedance in the secondary winding 62 and / or the spark plug 22.

[0028] It should be clear that the charging and / or discharging duration, as reflected in diagnostic signal 330, can be used to diagnose and evaluate a whole range of other operating parameters, in addition to those mentioned above. Since diagnostic signal 330 is a digital signal that is electrically isolated from engine ground 56, it exhibits relatively high noise immunity and allows the ECU 30 to effectively extract information about the charging and discharging phases.

[0029] Experts will recognize that the charging duration 350 and the discharging duration 360 are only partially defined by the diagnostic signal 330, as both the diagnostic signal and the trigger signal are required to fully define these durations or time periods (e.g., duration 350 begins with the rising edge of the trigger signal 320RE and ends with the falling edge of the diagnostic signal 330FE, and duration 360 begins with the falling edge of the trigger signal 320FE and ends with the rising edge of the diagnostic signal 330RE). If the ECU 30 only possessed the diagnostic signal 330, it could not fully evaluate the charging and discharging durations 350 and 360, as it would only have information about the start of these durations.Since the ECU 30 is the source of the trigger signal 320 and therefore knows the times of the rising and falling edges 320RE, 320FE, the ECU can use timing algorithms to evaluate the trigger and diagnostic signals together and determine the charging and discharging durations 350, 360 accordingly. In this way, the present method uses information from both a control signal sent by the ECU 30 to the ignition coil assembly 14 (the trigger signal) and a feedback signal sent from the ignition coil assembly to the ECU (the diagnostic signal) to determine specific durations. In various embodiments, the ignition circuit 64 could be modified so that the diagnostic signal 330 fully defines the charging and / or discharging durations 350, 360.

[0030] The preceding examples represent only some of the ways in which the ECU 30 can use, interpret, evaluate, analyze, and / or otherwise process information from the diagnostic signal 330, as numerous other possibilities are conceivable. The various current and voltage thresholds mentioned here can easily be changed or adapted for specific engines, ignition systems, spark plugs, etc. Furthermore, if a lower degree of immunity to electromagnetic interference is acceptable, it is possible to provide the ignition coil assembly as a single four-pin electrical connector, omitting a separate engine ground input terminal 56 and instead simply connecting it to the battery ground 54.

[0031] It is understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but is defined exclusively by the following claims. Furthermore, the statements contained in the foregoing description refer to specific embodiments and are not to be understood as limitations on the scope of the invention or the definition of the terms used in the claims, unless a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will be obvious to a person skilled in the art. All such other embodiments, changes, and modifications are intended to fall within the scope of the appended claims.

[0032] As used in this description and the claims, the terms "for example," "e.g.," "such," and "as," as well as the verbs "including," "having," "including," and their other verb forms, when used in conjunction with an enumeration of one or more constituents or other items, are each to be understood as open, meaning that the enumeration is not to be regarded as excluding other, additional constituents or items. Other terms are to be interpreted in their broadest, reasonable sense unless they are used in a context that requires a different interpretation.

Claims

[1] An ignition coil assembly (14) for use in an ignition system (10) comprising the following: a large number of input ports (50, 52, 54, 56); a to the output port (66); an ignition coil (58) with a primary winding (60) and with a secondary winding (62); and an ignition circuit (64) comprising an ignition operating circuit (100) and an ignition diagnostic circuit (102), wherein the ignition operating circuit is configured to control the charging and discharging of the ignition coil and is coupled to at least some of the input terminals and to the ignition coil, wherein the ignition diagnostic circuit is configured to monitor various aspects of the ignition system and is coupled to the ignition coil and the output terminal, wherein the ignition diagnostic circuit is configured to provide feedback to the ignition system by sending a diagnostic signal (330) via the output terminal, the diagnostic signal containing information representative of both a charging phase and a discharging phase. [2] The ignition coil arrangement (14) according to claim 1, wherein the plurality of input terminals (50, 52, 54, 56) comprises a first low-voltage input terminal (50) configured to receive low-voltage battery current from a battery (12), a second low-voltage input terminal (52) configured to receive a trigger signal (320) from an engine control unit (ECU) (30), a third low-voltage input terminal (54) configured to receive battery ground, and a fourth low-voltage input terminal (56) configured to receive engine ground, wherein the multiple input terminals and the output terminal (66) are part of a single multi-pole electrical connector (80), and where the battery ground and the engine ground are electrically isolated from each other, so that the diagnostic signal (330) is more immune to internal noise. [3] The ignition coil arrangement (14) according to claim 1 or 2, wherein the ignition operating circuit (100) comprises a driver circuit (112) and a switch (84), wherein the driver circuit has an input (142) configured to receive trigger signals (320) from an engine control unit (ECU) (30) and an output (146) configured to supply trigger signals to the switch, wherein the switch is an insulated-gate bipolar transistor (IGBT) and has a first terminal (130) connected to the primary winding (60) of the ignition coil (58), a second terminal (132) connected to the output of the driver circuit and configured to receive trigger signals, and a third terminal (134) connected to the ignition diagnostic circuit (102), and wherein the ignition operating circuit is configured such that the trigger signals cause the switch to be either "on" so that charging current (300) flows through the primary winding, or "off" so that no charging current flows through the primary winding. [4] The ignition coil arrangement (14) according to one of claims 1 to 3, wherein the ignition diagnostic circuit (102) comprises a charge evaluation circuit (160) coupled to the primary winding (60), a discharge evaluation circuit (162) coupled to the secondary winding (62), and a feedback integration circuit (164) coupled to the charge evaluation circuit, the discharge evaluation circuit, and the output terminal (66). [5] The ignition coil arrangement (14) according to claim 4, wherein the charge evaluation circuit (160) includes a resistor (170), an operational amplifier (172) and a charge evaluation output (174), where the resistor is connected in series with the primary winding (60) in a charging path, wherein the operational amplifier has a first input (182) connected to a terminal (176) of the resistor, a second input (184) connected to a reference voltage (V REF) is connected, and has an output (186) connected to the charge evaluation output, wherein the charge evaluation output is connected to the feedback integration circuit (164), wherein the charging evaluation circuit is configured to output an active charging signal when a charging current (300) flowing through the charging path exceeds a charging current threshold, and wherein the charging evaluation circuit is configured to output an inactive charging signal when the charging current flowing through the charging path does not exceed the charging current threshold, and where the charging current threshold is at least partially determined by the reference voltage (V REF ) is determined. [6] The ignition coil arrangement (14) according to claim 4 or 5, wherein the charging evaluation circuit (160) is configured to output an active charging signal to the feedback integration circuit (164) when a charging current (300) flowing through a charging path is greater than a charging current threshold value, wherein the feedback integration circuit (164) is configured to combine the active charging signal with the output signal of the discharge evaluation circuit (162) to generate the diagnostic signal (330), wherein the diagnostic signal contains a rising edge (330FE) or a falling edge at time (t1) that is representative of the active charging signal and which can be used in conjunction with a separate trigger signal (320) to determine a charging duration (350) of (t1- t0), wherein the charging duration corresponds to a time interval required by the charging current to exceed the charging current threshold, and wherein the charging duration is representative of a state or condition of the primary winding (60). [7] The ignition coil arrangement (14) according to one of claims 4 to 6, wherein the discharge evaluation circuit (162) comprises an opto-isolater (190) with a light-emitting device (192) and a light-activated switch (194), a resistor (220) and a discharge evaluation output (222), wherein the light-emitting device is connected in series with the secondary winding (62) in a discharge path, wherein the light-activated switch is operationally coupled to the light-emitting device and has a terminal (210) which is connected to a terminal of the resistor, wherein the discharge evaluation output is connected to the feedback integration circuit (102), wherein the discharge evaluation circuit is configured to output an active discharge signal when a discharge current (310) flowing through the discharge path exceeds a discharge current threshold, and wherein the discharge evaluation circuit is configured to output an inactive discharge signal when the discharge current flowing through the discharge path does not exceed the discharge current threshold, and where the discharge current threshold is determined at least partially by properties of the light-emitting device and / or the light-activated switch. [8] The ignition coil arrangement (14) according to any one of claims 4 to 7, wherein the discharge evaluation circuit (162) is configured to output an active discharge signal to the feedback integration circuit (164) when a discharge current (310) flowing through a discharge path is less than a discharge current threshold value, wherein the feedback integration circuit is configured to combine the active discharge signal with the output signal from the charge evaluation circuit (160) to generate the diagnostic signal (330), wherein the diagnostic signal contains a rising edge (330RE) or a falling edge at time (t3) which is representative of the active discharge signal and can be used in conjunction with a separate trigger signal (320) to determine a discharge duration (360) of (t3 - t2), wherein the discharge duration corresponds to a time period required for the discharge current to fall below the discharge current threshold, and wherein the discharge duration is representative of a state or condition of the secondary winding (62) or a corresponding spark plug (22). [9] The ignition coil arrangement (14) according to any one of claims 4 to 8, wherein the feedback integration circuit (164) includes a logic gate (240) and a switch (242), wherein the logic gate has a first input (250) connected to a charge evaluation output (174) of the charge evaluation circuit (160) and configured to receive a charge signal, a second input (252) connected to a discharge evaluation output (222) of the discharge evaluation circuit (162) and configured to receive a discharge signal, and an output (254) configured to provide a combined charge and discharge signal, wherein the switch has a first terminal (260) which is connected to the output terminal (66) and a second terminal (262) which is connected to the output of the logic gate and is configured to receive the combined charge and discharge signal, and wherein the feedback integration circuit is configured to use the combined charge and discharge signal to output the diagnostic signal (330) via the output terminal. [10] The ignition coil arrangement (14) according to any one of claims 1 to 8, wherein the diagnostic signal (330) provides continuous feedback to the ignition system (10) and contains information that is representative of both a charging signal generated during the charging phase and a discharging signal generated during the discharging phase, and wherein the ignition circuit (64) is configured to combine the charging signal and the discharging signal to form the diagnostic signal and to provide the combined diagnostic signal via the output terminal (66), which is a single pin in a multi-pin electrical connector (80). [11] The ignition coil assembly (14) according to any one of claims 1 to 10, wherein the output terminal (66) of the ignition coil assembly is connected or connected to one or more additional output terminal(s) of one or more additional ignition coil assembly(s), such that a plurality of diagnostic signals (330) are supplied to an engine control unit (ECU) (30) via a single cable or connection, and wherein the ECU processes the plurality of diagnostic signals based on a time specified by the ignition timing of the ignition system (10). [12] A method for operating an ignition coil arrangement (14) for use in an ignition system (10), the ignition coil arrangement comprises the following: a large number of input ports (50, 52, 54, 56); an output port (66); an ignition coil (58) with a primary winding (60) and with a secondary winding (62); and an ignition circuit (64) with an ignition operating circuit (100) and with an ignition diagnostic circuit (102); the procedure comprises the following steps: Control of charging and discharging of the ignition coil via the ignition circuit; Monitoring various aspects of the ignition system with the ignition diagnostic circuit; and Providing feedback from the ignition diagnostic circuit to the ignition system by sending a diagnostic signal (330) via the output terminal, wherein the diagnostic signal contains information that is representative of both a charging phase and a discharging phase. [13] The method according to claim 12, wherein the monitoring step further comprises: monitoring a charging current (300) flowing through a charging path comprising the primary winding (60), a switch (84) and a resistor (170), and Using an operational amplifier (172) to apply a voltage to one terminal (176) of the resistor with a threshold voltage V REF to compare and output an active charging signal when the voltage exceeds the threshold voltage, indicating that the charging current has exceeded a charging current threshold. [14] The method according to claim 12 or 13, wherein the step of providing feedback further comprises providing continuous feedback by sending the diagnostic signal (330) which combines an active charging signal from a charging evaluation circuit (160) with an output signal from a discharging evaluation circuit (162), wherein the diagnostic signal contains a rising edge or a falling edge (330FE) at time (t1) that is representative of the active charging signal, and wherein this step further comprises the following steps: Evaluating the diagnostic signal at an engine control unit, ECU (ECU = Engine Control Unit), (30) in conjunction with a separate trigger signal (320) to determine a charging time (350) of (t1-t0), wherein the charging time corresponds to a duration required for a charging current (300) flowing through a charging path containing the primary winding (60) to reach a charging current threshold value, and Determining a state or condition of the primary winding based on the charging time. [15] The method according to any one of claims 12 to 14, wherein the monitoring step further comprises: monitoring a discharge current (310) flowing through a discharge path comprising the secondary winding (62) and a current evaluator (190) with a light-emitting device (192) and with a light-activated switch (194), Terminating the emission of light from the light-emitting device when the discharge current flowing through the discharge path does not exceed a discharge current threshold, “turning off” the light-activated switch when the light-emitting device stops emitting light, and issuing an active discharge signal when the light-activated switch is “turned off”, indicating that the discharge current has fallen below the discharge current threshold. [16] The method according to any one of claims 12 to 15, wherein the step of providing feedback further comprises providing continuous feedback by sending a diagnostic signal (330) which combines an active discharge signal from a discharge evaluation circuit (162) with an output signal from a charge evaluation circuit (160), wherein the diagnostic signal contains a rising edge (330RE) or a falling edge at time (t3) that is representative of the active discharge signal, and wherein this step further comprises the following steps: Evaluating the diagnostic signal at an engine control unit, ECU (ECU = Engine Control Unit), (30) in conjunction with a separate trigger signal (320) to determine a discharge duration (360) of (t3 - t2), wherein the discharge duration corresponds to a time period required for a discharge current flowing through a discharge path containing the secondary winding (62) to fall below a discharge current threshold, and Determining a state or condition of the secondary winding or a corresponding spark plug (22) based on the discharge duration.

Images