Measuring spark of a spark plug

Abstract

The subject matter of this specification can be embodied in, among other things, an internal combustion engine ignition system including a voltage divider configured to be coupled to a primary transformer ignition coil connector, the voltage divider configured to reduce a voltage received from the primary transformer ignition coil to a controller voltage, a comparator circuit having an input coupled to an output of the voltage divider, and a controller configured to detect a voltage output of the voltage divider, detect a voltage output of a vehicle power supply, detect a voltage output of the comparator, and determine an estimated breakdown voltage of a spark plug based on the detected voltage output of the voltage divider and the detected voltage of the power supply.

Description

[0001] Priority requirements

[0002] This application claims priority to U.S. Patent Application No. 17 / 934,451, filed September 22, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the ignition system of an internal combustion engine. Background Technology

[0004] Some reciprocating internal combustion engines use a spark ignition module to generate the air-fuel ratio within the cylinder. The spark ignition module operates by boosting the current in the primary coil of a high-turn-ratio transformer and then interrupting the primary current. This is achieved by connecting one end of the primary winding to a positive battery voltage. In some implementations, a transistor is used as a switch to connect the other primary terminal to ground. Summary of the Invention

[0005] This disclosure relates to measuring the spark of a spark plug.

[0006] In a first example, an internal combustion engine ignition system includes: a voltage divider configured to be coupled to a primary transformer ignition coil connector, the voltage divider being configured to reduce a voltage received from the primary transformer ignition coil to a controller voltage; a comparator circuit having an input coupled to an output of the voltage divider; and a controller configured to detect the voltage output of the voltage divider, detect the voltage output of a vehicle power supply, detect the voltage output of the comparator, and determine an estimated breakdown voltage of a spark plug based on the detected output voltage of the voltage divider and the detected voltage of the power supply.

[0007] In the second example, according to Example 1, the controller is further configured to determine the estimated spark duration based on the determined comparator voltage output.

[0008] In the third example, according to Example 1 or 2, the voltage divider is configured to reduce the voltage to approximately one percent.

[0009] In the fourth example, according to any of Examples 1 to 3, the system further includes a blanking circuit coupled to a second input of the comparator, the blanking circuit being configured to reduce noise during measurement.

[0010] In the fifth example, according to Example 4, the blanking circuit includes a transistor, a resistor electrically coupled to the gate and pin of the transistor, and a capacitor coupled in parallel to the resistor.

[0011] In the sixth example, according to any of Examples 1 to 5, the comparator circuit is a first comparator circuit, and the ignition system further includes a second comparator circuit.

[0012] In the seventh example, a method includes measuring a power supply voltage; initiating a drain on the spark plug; measuring the voltage from the output of a voltage divider coupled to the primary coil; after a period of time following the initiation of the drain, measuring the output of a first voltage comparator that compares the output of the voltage divider with a threshold voltage; and determining the output value of the voltage comparator.

[0013] In the eighth example, according to Example 7, measuring the output of the voltage comparator includes measuring the integrated voltage output of the voltage comparator over a sufficient duration to determine the spark breakdown voltage.

[0014] In the ninth example, according to Example 7 or 8, the method further includes: determining that the output voltage of the first comparator is higher than a specified threshold; determining that the output voltage of the second comparator is lower than a specified threshold; and determining that an ignition failure has occurred based on determining that the output of the comparator is higher than the specified threshold and the output of the second comparator is lower than the specified threshold.

[0015] In the tenth example, according to any of Examples 7 to 9, the method further includes: determining that the output voltage of the comparator is lower than a specified threshold; and determining that a short circuit exists based on determining that the output voltage of the comparator is lower than a certain threshold.

[0016] In the eleventh example, according to Example 7, the method further includes: determining an estimated breakdown voltage of the spark plug based on the voltage output of a determined comparator; and determining an estimated spark duration based on the output voltage of a determined first comparator.

[0017] In the twelfth example, according to Example 11, determining the estimated breakdown voltage and the estimated spark duration includes determining the values ​​within the lookup table.

[0018] In the thirteenth example, determining the estimated breakdown voltage and the estimated spark duration, according to Example 11 or 12, involves using empirical functions.

[0019] In the fourteenth example, according to any of Examples 11 to 13, the method further includes replacing the spark plug in response to a determined spark duration and a determined voltage breakdown.

[0020] In the fifteenth example, an engine system includes an internal combustion engine and an ignition system coupled to the internal combustion engine, the ignition system including: a power supply; a primary transformer coil; a secondary transformer coil coupled to the primary transformer coil; a voltage divider coupled to the primary transformer coil, the voltage divider being configured to reduce a voltage to a controller voltage; a comparator circuit coupled to the output of the voltage divider; and a controller configured to: detect the voltage output of the voltage divider, detect the voltage output of the power supply, detect the voltage output of the comparator, and determine an estimated spark duration based on the determined comparator voltage output.

[0021] In the sixteenth example, according to Example 15, the controller is further configured to determine the estimated breakdown voltage of the spark plug based on the detected output voltage of the voltage divider and the detected voltage of the power supply.

[0022] In the seventeenth example, according to example 15 or 16, the engine system further includes a blanking circuit coupled to a second input of the comparator.

[0023] In the eighteenth example, according to Example 17, the blanking circuit includes a transistor, a resistor electrically coupled to the gate and pin of the transistor, and a capacitor coupled in parallel to the resistor.

[0024] In the nineteenth example, according to any one of Examples 15 to 18, the comparator circuit is a first integrator circuit, and the ignition system further includes a second comparator circuit.

[0025] In the twentieth example, according to any of Examples 15 to 19, the voltage divider is configured to reduce the voltage to approximately one percent.

[0026] In the twenty-first example, according to any of Examples 15 to 20, the power source includes a battery.

[0027] In one example embodiment, an internal combustion engine ignition system includes: a voltage divider configured to be coupled to a primary transformer ignition coil connector, the voltage divider being configured to reduce a voltage received from the primary transformer ignition coil to a controller voltage; a comparator circuit having an input coupled to an output of the voltage divider; and a controller configured to detect the voltage output of the voltage divider, detect the voltage output of a vehicle power supply, detect the voltage output of the comparator, and determine an estimated breakdown voltage of the spark plugs based on the detected output voltage of the voltage divider and the detected voltage of the power supply.

[0028] Various embodiments may include some, all, or none of the following features. The controller may be configured to determine an estimated spark duration based on a determined comparator voltage output. The voltage divider may be configured to reduce the voltage to substantially one percent. The system may include a blanking circuit coupled to a second input of the comparator, the blanking circuit being configured to reduce noise during measurement. The blanking circuit may include a transistor, a resistor electrically coupled to the gate and pins of the transistor, and a capacitor coupled in parallel to the resistor. The comparator circuit may be a first comparator circuit, and the ignition system further includes a second comparator circuit.

[0029] In an example implementation, a method may include: measuring a power supply voltage; initiating a pause for a spark plug; measuring the voltage from the output of a voltage divider coupled to a primary coil; after a duration following the initiation of the pause, measuring the output of a first voltage comparator that compares the output of the voltage divider with a threshold voltage; and determining the output value of the voltage comparator.

[0030] Various implementations may include some, all, or none of the following features. Measuring the output of the voltage comparator may include measuring the integrated voltage output of the voltage comparator over a sufficient duration to determine the spark breakdown voltage. The method may include: determining that the output voltage of the first comparator is above a specified threshold; determining that the output voltage of the second comparator is below a specified threshold; and determining that a misfire has occurred based on determining that the output of the first comparator is above the specified threshold and the output of the second comparator is below the specified threshold. The method may include: determining that the output voltage of the comparator is below a specified threshold; and determining that a short circuit exists based on determining that the output voltage of the comparator is below a certain threshold. The method may include: determining an estimated breakdown voltage of the spark plug based on the determined voltage output of the comparator; and determining an estimated spark duration based on the determined output voltage of the first comparator. Determining the estimated breakdown voltage and the estimated spark duration may include determining values ​​in a lookup table. Determining the estimated breakdown voltage and the estimated spark duration may include using an empirical function. The method may include replacing the spark plug in response to the determined spark duration and the determined voltage breakdown.

[0031] In another example embodiment, an engine system includes: an internal combustion engine; and an ignition system coupled to the internal combustion engine, the ignition system including: a power supply; a primary transformer coil; a secondary transformer coil coupled to the primary transformer coil; a voltage divider coupled to the primary transformer coil, the voltage divider being configured to reduce the voltage to a controller voltage; a comparator circuit coupled to the output of the voltage divider; and a controller configured to detect the voltage output of the voltage divider, detect the voltage output of the power supply, detect the voltage output of the comparator, and determine an estimated spark duration based on the determined comparator voltage output.

[0032] Various embodiments may include some, all, or none of the following features. The controller may be configured to determine the estimated breakdown voltage of the spark plug based on the detected output voltage of the voltage divider and the detected voltage of the power supply. The engine system may include a blanking circuit coupled to a second input of the comparator. The blanking circuit may include a transistor, a resistor electrically coupled to the gate and pins of the transistor, and a capacitor coupled in parallel to the resistor. The comparator circuit may be a first integrator circuit, and the ignition system further includes a second comparator circuit. The voltage divider may be configured to reduce the voltage to substantially one percent. The power supply may include a battery.

[0033] Details of one or more embodiments are set forth in the following figures and description. Other features, objects, and advantages will be apparent from this disclosure. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an example internal combustion engine system.

[0035] Figure 2 This is a partial wiring diagram of an example internal combustion engine ignition system.

[0036] Figure 3 A set of charts is shown, illustrating examples of measurement signals and timing at different points in an internal combustion ignition system.

[0037] Figure 4 This is a block diagram of an example controller that can be used with various aspects of this disclosure.

[0038] Figure 5 This is a flowchart of an example method that can be used with various aspects of this disclosure.

[0039] The same reference symbol in different drawings indicates the same element. Detailed Implementation

[0040] During operation, the ignition system of a reciprocating internal combustion engine ignites the spark plugs at the desired time to properly ignite the air-fuel mixture in each cylinder. The engine controller typically relies on a knock sensor to notify the controller of ignition problems, or on thermocouples to measure cylinders that are not igniting. Such problems are usually caused by worn or improperly installed spark plugs.

[0041] This disclosure describes direct monitoring of spark plugs to troubleshoot potential ignition problems caused by spark plugs and also provides prediction to avoid engine starting failures. This disclosure describes monitoring spark plugs so that they can be replaced before problems arise. A voltage divider is configured to be coupled to the primary transformer ignition coil connector. The voltage divider is configured to reduce the voltage received from the primary transformer ignition coil to a level that the controller can read. A comparator circuit has an input coupled to the output of the voltage divider. The controller is configured to detect the voltage output of the voltage divider, the voltage output of the vehicle or engine, the voltage output of the power supply, and the voltage output of the comparator. The controller is then configured to determine an estimated breakdown voltage of the spark plug based on the time response of the comparator to the detected output voltage of the voltage divider and the detected battery voltage. The controller is also configured to determine an estimated spark duration based on the time response of a second comparator. These parameters can be used to determine the health condition of the spark plugs during engine operation.

[0042] Figure 1 This is a schematic diagram of an example internal combustion engine system 100. The internal combustion system includes an internal combustion engine 102 using spark ignition. The ignition system includes spark plugs 104 in each cylinder 106. Each spark plug 104 is electrically coupled to a coilpack 108. Although illustrated and described with coilpack 108, other configurations may be used without departing from this disclosure. For example, a single coilpack 108 may be used. Each coilpack 108 includes a primary ignition coil 110 and a secondary ignition coil 112. The primary ignition coil 110 is selectively directly coupled to a power source 114 via a low-side switch in a controller 116. During operation, the controller 116 switch is closed, and it then applies a power source or battery potential across the primary coil. The current in the primary ignition coil 110 then increases linearly over time. This charging of the primary ignition coil 110 is referred to as the pause time. When the controller removes the applied voltage, the energy stored in the primary ignition coil 110 is transferred to the secondary ignition coil via magnetic coupling as a very high voltage (i.e., 10-40 kV). This high voltage ionizes the air gap in the spark plug 104. Once the air gap is ionized and an arc is established, the voltage across the secondary ignition coil 112 drops significantly. Discharge continues until the energy in the secondary ignition coil 112 is dissipated by the spark and the primary ignition coil voltage returns to the supply voltage.

[0043] In some implementations, power source 114 may include a battery or a supercapacitor. Additional power conditioning, generation, and regulation components may also be used within the power source; for example, an alternator may be used to recharge the battery. Alternatively or additionally, a smoothing capacitor may be used to reduce voltage and current fluctuations in the system.

[0044] Figure 2 This is a wiring diagram of an example circuit 200 for the diagnostic and predictive portion of an internal combustion engine ignition system. A voltage divider 202 is configured to be coupled to the primary ignition coil connector 250. The voltage divider 202 is configured to reduce the voltage received from the primary ignition coil 110 to the controller voltage (labeled "Vpri" in the illustrated embodiment), i.e., a level that can be read by the controller 116. For example, the voltage divider can reduce the voltage to one percent. The controller voltage can vary from a 2-volt input to a 36-volt input. Other controller voltages can be used without departing from this disclosure.

[0045] The first comparator circuit 204 has an input coupled to the output of the voltage divider 202. In the illustrated embodiment, this connection is Vpri. In some embodiments, the second comparator circuit 206 is also coupled to the output of the voltage divider 202. The first comparator circuit 204 compares the voltage at Vpri with a predetermined threshold voltage labeled "Vbd_thresh". The second comparator circuit compares the voltage at Vpri with a second predetermined threshold voltage labeled "Vdur_thresh". In some embodiments, the second threshold voltage is different from the first threshold voltage.

[0046] In some implementations, the blanking circuit 208 modifying Vbd_thresh is coupled to the second input of the first comparator 204. In some implementations, the blanking circuit 208 includes a transistor 210, a resistor 212 electrically coupled to the gate and pin of the transistor 210 (for setting a bias voltage), and a capacitor 214 coupled in parallel to the resistor (for setting a blanking time). The blanking circuit 208 is configured to reduce noise during measurement, for example, by blanking for a set duration when ringing (i.e., high-frequency oscillation) may be present. In some cases, such a blanking time is 2 to 5 microseconds. For the illustrated implementation, this blanking behavior is... Figure 3 The vbd_thresh trace is used to illustrate this. In some implementations, additional components such as additional transistors, resistors, or capacitors may be included in the blanking circuit.

[0047] During operation, the voltage Vpri at the output of the voltage divider is detected. Additionally, the voltage output of the power supply (e.g., a battery) is measured. Finally, the integrated output voltages of the first comparator 204 (labeled "vbd") and the second comparator 206 (labeled "vdur") are also detected. Based on these measurements, the breakdown voltage of the spark plug 104 and the spark duration of the spark plug 104 can be determined. In some embodiments, the spark plug breakdown voltage can be determined based on the detected output voltage of the voltage divider and the detected voltage of the power supply. In some embodiments, the estimated spark duration can be determined based on the average voltage output of the second comparator 206. In some embodiments, such determination can be made by the controller 116.

[0048] The following is a description of the illustrated embodiments during operation. It should be noted that the following are merely example operations of example circuits that can be used with various aspects of this disclosure. Minor changes to the circuits or operations described herein may still be covered by this disclosure.

[0049] When any pause input (shown as pause connector 216 and in) Figure 3 When the indicator marked "pause" is determined to be high, transistors M1 and M2 discharge integrating capacitors C1 and C2 to essentially 0 volts within 200µs. This... Figure 3 The diagram illustrates this with output voltages labeled "Vbd" and "Vdur," which represent the desired spark breakdown and duration measurements. This discharge prepares circuit 200 to integrate information from the VPri signal (i.e., the output voltage of voltage divider 202).

[0050] After the pause and drop, the voltage of the primary ignition coil 110 is clamped high for the time required to reach the spark plug breakdown voltage. At the reduced voltage, Vpri follows the same trend. The time to reach the spark plug breakdown voltage depends on several operating parameters, but for example circuit 200, it has been empirically established as approximately ten microseconds. In some cases, the primary ignition coil 110 may have parasitic inductance, which can cause unpredictable ringing (high-frequency oscillation) on the primary ignition coil voltage during the breakdown event and spark duration. Circuit 200 first measures the high time of the primary ignition coil voltage pulse, which is proportional to the spark breakdown voltage. A first comparator 204 (U1) utilizes a leading-edge blanking threshold. In some implementations, such a threshold is essentially 37% of the power supply (i.e., battery) voltage. In some implementations, Vbd_thresh is varied by using transistors M3 (210) and M4 via blanking circuit 208, using a time delay threshold that integrates the blanking to subtract an additional constant offset of 2 to 5 microseconds from the leading edge of the Vpri signal. Figure 3This behavior is illustrated. After this blanking time, C1 integrates the remaining width of the Vpri pulse to produce a readable output voltage that subtracts the contribution of the blanking interval to the output (Vbd) of the first comparator circuit 204.

[0051] Following the initial pulse, the primary ignition coil voltage drops and remains slightly above the supply voltage, potentially with more ringing, until the energy in the primary ignition coil 110 is dissipated and the spark is extinguished. After this, the primary coil voltage drops to the supply drive voltage. The duration of the spark event is integrated by C2 during the period when the primary coil voltage is above the supply voltage by more than 12% of the nominal supply voltage. In some cases, this duration is essentially 1-5 milliseconds, for example, with a pause of less than 10 amps of current flowing through the primary ignition coil 110. During the duration of integration, the output from the second comparator 206 (the nDurDone signal) is approximately 5V. The falling edge of this signal indicates the completion of the measurement.

[0052] Figure 3 This is a set of graphs illustrating examples of voltage and timing measurements at various nodes of an internal combustion ignition system. The waveforms shown are typical of the operations described herein. The graphs provide an overview of the signals and timing involved throughout the measurement process at various nodes of the internal combustion ignition system. Figure 2 The text describes and references each waveform by name. Figure 3 Each individual chart in corresponds to Figure 2 The marked nodes in the text.

[0053] Figure 4 This is a block diagram of a controller that can be used with various aspects of this disclosure. Controller 116 can in particular monitor system parameters and send signals to actuate and / or adjust various operating parameters of the system. For example... Figure 4As shown, in some cases, controller 116 includes processor 450 (e.g., implemented as one or more processors) and memory 452 (e.g., implemented as one or more memories), the memory 452 containing instructions that cause processor 450 to perform the operations described herein. Processor 450 is coupled to input / output (I / O) interface 454 for sending and receiving communication with components in the system, including, for example, coil package 108. In some cases, controller 116 may additionally communicate status to one or more of the various system components of system 100 and other sensors provided in system 100 (e.g., pressure sensors, temperature sensors, vibration sensors, and other types of sensors) and send actuation and / or control signals to one or more of the various system components of system 100 and other sensors provided in system 100 (e.g., pressure sensors, temperature sensors, vibration sensors, and other types of sensors). In some cases, controller may communicate status to one or more components within system 100 (such as coil package 108) and send actuation and control signals. Communication can be hardwired, wireless, or a combination of wired and wireless. In some embodiments, controller 116 can be a distributed controller, with different parts located around the vehicle or location. For example, in some cases, controller 116 may be located near engine 102, or it may be located in a separate compartment (such as a control room or passenger cabin). Without departing from this disclosure, additional controllers can be used as standalone or networked controllers across locations or vehicles.

[0054] The controller 116 can operate in the ignition system to monitor, command, and use the system to measure spark duration and breakdown voltage. Input and output signals (including data from sensors or nodes) controlled and monitored by the controller 116 can be continuously logged by the controller 116.

[0055] The controller 116 may have varying degrees of autonomy in controlling the ignition system. For example, the controller 116 may begin sensing spark plug problems and alert the operator. Alternatively, the controller 116 may begin sensing spark plug problems, receive additional input from the operator, and begin adjusting the ignition operation (e.g., changing the cylinder firing order or omitting cylinder firing) without further input from the operator. Alternatively, the controller 116 may begin sensing spark plug problems and adjust the ignition operation without input from the operator.

[0056] Figure 5This is a flowchart of an example method 500 that can be used with various aspects of this disclosure. In some embodiments, all or part of method 500 may be executed by controller 116. At 502, the power supply voltage is measured. Although primarily described as a battery, other power sources, such as an alternator or a supercapacitor, may be used without departing from this disclosure. At 504, a stop is initiated on the spark plugs. That is, power is sent to coil package 108 for a period of time.

[0057] At 506, for example, the voltage from the output of the voltage divider coupled to the primary coil is measured by controller 116. After a certain duration following the start-up pause, at 508, the output of a first voltage comparator 204, which compares the output of the voltage divider with a threshold voltage, is measured. Measuring the output of the voltage comparator involves measuring the output of the voltage comparator for a sufficient duration to determine the falling edge of the pause. For example, in some cases, 25 milliseconds is a sufficient duration.

[0058] At 510, the average output value of the first voltage comparator 204 is determined. In some cases, the average voltage output of the voltage comparator 204 is determined to be below a specified threshold, for example, 37% of the nominal supply voltage. In such cases, a short circuit is determined to exist based on the fact that the comparator's output voltage is below the specified threshold.

[0059] In some cases, the average output voltage of the first comparator 204 is determined to be higher than a specified threshold, for example, 37% higher than the nominal supply voltage. In some cases, the average output voltage of the second comparator is determined to be higher than a specified threshold. For example, in some cases, a voltage 12% higher than the nominal supply voltage may be used. When the average voltage of the first comparator is higher than an empirically determined threshold and the average voltage of the second comparator is lower than another empirically determined threshold, it is determined that an ignition failure has occurred based on the fact that the average voltage of the first comparator is higher than the specified threshold and the average voltage of the second comparator is lower than the specified threshold.

[0060] In some embodiments, the average output of the first comparator 204 is used to determine the estimated breakdown voltage of the spark plug. Alternatively or additionally, the estimated spark duration is determined based on the determined average output voltage of the second comparator 206. In some embodiments, the estimated breakdown voltage and the estimated spark duration are determined by finding values ​​in a lookup table. In some embodiments, such a lookup table may be stored in the memory 452 of the controller 116. Figure 4In some implementations, empirical functions are used to determine the estimated breakdown voltage and the estimated spark duration. Where the estimated breakdown voltage and the estimated spark duration exceed the specifications for a particular spark plug 104, the particular spark plug can be changed based on the determined spark duration and determined breakdown voltage outside the specifications.

[0061] Many embodiments have been described. However, it will be understood that various modifications can be made without departing from the spirit and scope of this disclosure. For example, the system included herein can be applied to internal combustion engines having two, three, four, five, six, eight, or sixteen cylinders. Therefore, other embodiments are within the scope of the following claims.

Claims

1. An internal combustion engine ignition system, comprising: A voltage divider configured to be coupled to the primary transformer ignition coil connector, the voltage divider being configured to reduce the positive voltage received from the primary transformer ignition coil and provide the reduced positive voltage as the positive controller voltage at the voltage output of the voltage divider; and The controller is configured to: Measure the reduced positive controller voltage output by the voltage divider; Measure the vehicle's power supply voltage; and The estimated breakdown voltage of the spark plug is determined based on the measured reduced positive controller voltage and the measured vehicle power supply voltage.

2. The system of claim 1, further comprising a comparator circuit having an input coupled to a voltage output of a voltage divider, wherein the controller is further configured to measure the positive voltage output of the comparator circuit and determine an estimated spark duration based on the measured positive voltage output of the comparator circuit.

3. The system according to claim 1, wherein, The voltage divider is configured to reduce the positive voltage to one percent.

4. The system of claim 2, further comprising a blanking circuit coupled to a second input of the comparator circuit, the blanking circuit being configured to reduce noise during measurement.

5. The system according to claim 4, wherein, The blanking circuit includes: transistor; A resistor electrically coupled to the gate and pins of the transistor; and A capacitor is connected in parallel to the resistor.

6. The system according to claim 2, wherein, The comparator circuit is a first comparator circuit, and the internal combustion engine ignition system further includes a second comparator circuit.

7. A method comprising: Measure the power supply voltage; Initiate a pause on the spark plugs; A voltage divider coupled to the primary coil reduces the positive voltage received from the primary coil and provides the reduced positive voltage as the positive controller voltage at the voltage output of the voltage divider; Measure the reduced positive voltage from the voltage divider output; After a certain duration following the initiation of the pause, the output of the first voltage comparator that compares the positive controller voltage with the positive threshold voltage is measured; as well as Determine the output voltage of the voltage comparator.

8. The method according to claim 7, wherein, Measuring the reduced positive voltage from the voltage divider's output involves measuring the integrated voltage output of the voltage divider over a predetermined duration to determine the spark breakdown voltage.

9. The method of claim 7, further comprising: Determine that the output voltage of the first comparator is higher than a specified threshold. Determine that the output voltage of the second comparator is below a specified threshold; as well as It is determined that an ignition failure has occurred based on the fact that the output of the comparator is higher than the specified threshold and the output of the second comparator is lower than the specified threshold.

10. The method of claim 7, further comprising: The comparator's output voltage is determined to be below a specified threshold. as well as A short circuit is determined to exist based on the comparator's output voltage being below a certain threshold.

11. The method of claim 7, further comprising: The estimated breakdown voltage of the spark plug is determined based on the voltage output of the comparator. as well as The estimated spark duration is determined based on the output voltage of the first comparator.

12. The method according to claim 11, wherein, Determining the estimated breakdown voltage and estimated spark duration involves determining the values ​​within the lookup table.

13. The method according to claim 11, wherein, Determining the estimated breakdown voltage and the estimated spark duration involves using empirical functions.

14. The method of claim 11, further comprising replacing the spark plug in response to a determined spark duration and a determined voltage breakdown.

15. An engine system comprising: internal combustion engine; as well as An ignition system coupled to the internal combustion engine, the ignition system comprising: power supply; Primary transformer coil; A secondary transformer coil coupled to the primary transformer coil; A voltage divider coupled to the primary transformer coil, the voltage divider being configured to reduce the positive coil voltage to the positive controller voltage; A comparator circuit coupled to the positive voltage output of the voltage divider; and The controller is configured as follows: Measure the reduced positive controller voltage output from the voltage divider; Measure the vehicle power supply voltage; Measure the positive comparator voltage output of the comparator circuit; and The estimated spark duration is determined based on the average of the measured positive comparator voltage output.

16. The engine system according to claim 15, wherein, The controller is further configured to determine the estimated breakdown voltage of the spark plug based on the measured reduced positive voltage output and the measured vehicle power supply voltage.

17. The engine system of claim 15, further comprising a blanking circuit coupled to a second input of the comparator.

18. The engine system according to claim 17, wherein, The blanking circuit includes: transistor; A resistor electrically coupled to the gate and pins of the transistor; and A capacitor is connected in parallel to the resistor.

19. The engine system according to claim 15, wherein, The comparator circuit is a first integrator circuit, and the ignition system further includes a second comparator circuit.

20. The system according to claim 15, wherein, The voltage divider is configured to reduce the positive voltage to one percent.

21. The system according to claim 15, wherein, The power source includes a battery.

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