JP2829632B2 - Ignition system for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition system for an internal combustion engine having improved engine operating capability by controlling the ignition timing and efficiently designing the ignition system. is there. In particular, it relates to the efficient combustion of lean air-fuel mixtures.

BACKGROUND OF THE INVENTION In order to initiate a mixed air-fuel explosion in an internal combustion engine room, an ignition system that produces a high energy arc at the appropriate time in the engine operating cycle is used. The start of the energy arc across the spark plug gap is timed so that the crankshaft rotation of the engine occurs a predetermined number of times before the piston reaches top dead center. With proper spark timing, the flame coming out of the spark plug causes a pressure peak after TDC. If the spark is too slow, the pressure in the cylinder will not be output effectively. On the other hand, if the spikes are too fast, extremely high pressures and heat will be generated and may not be effective output.

Premature sparks cause various cylinder phenomena. The auto-ignition of the end gas (unburned mixed fuel) is activated when the temperature and pressure in the cylinder become too high.
Due to natural explosion of gas. When auto-ignition occurs in a cylinder, the pressure rises and falls alternately due to the sudden release of chemical energy, causing the temperature to rise sharply. If the energy release rate is high enough, vibrations in the explosive gas will cause the cylinder walls to vibrate and a distinctive sound of "Brun" will be heard.
Rapid fluctuations in gas pressure and temperature in the cylinder occur after top dead center.

It is believed by many engine designers that a slight degree of auto-ignition is preferred because when the speed of the flame coming out of the spark plug slows, it creates a stir that will explode the explosion. Auto-ignition reduces unburned residual hydrocarbons and uses the energy released when burned, resulting in lower hydrocarbon emissions and better fuel efficiency. Thus, engine designers attempt to calibrate the ignition system (hereafter "calibration") so that the spark is as early as the start of automatic ignition. However, excessive automatic ignition must be avoided. Otherwise, the temperature in the cylinder will be too high and the spark plug electrodes will be overheated,
This is because the well-known phenomenon of "pre-ignition"-the start of an explosion independent of sparks-occurs. Pre-ignition is manifested by too high a temperature and pressure near top dead center, causing damage such as a perforated piston. Preignition is manifested as "knocking", the sound it makes. Generally, it is said that automatic ignition causes pre-ignition, and pre-ignition further causes automatic ignition.

Many factors-intake air temperature, engine speed, load, fuel mixture, fuel specialty, etc.-affect the timing of automatic ignition. Spark plugs also directly affect fuel efficiency and harmful gas emissions. Because it is important to control the spark timing accurately,
Currently, many engine control systems have a closed circuit spark timing control system using a microprocessor. The control system simultaneously measures parameters such as exhaust gas components and cooling water temperature, and the occurrence of knocking. This system processes the data so as to match a predetermined automatic ignition start timing. Current knocking detectors using a spark controller use a piezoelectric transducer that detects vibrations due to knocking. However, this detector cannot detect the onset of auto-ignition because it cannot sufficiently detect the initial auto-ignition. Therefore, there is a need to provide an ignition control system that can detect initial auto-ignition and more accurately define spark timing in closed circuit systems.

Designers of ignition systems for internal combustion engines in vehicles strive to make the engine internal combustion with low fuel mixture. A mixture having a mixture ratio of air to fuel of about 15: 1 is called a stoichiometric mixture and provides enough oxygen for combustion. However, if air is excessively introduced into the cylinder, nitrogen oxides (NO
Reduce harmful emissions such as X) and hydrocarbons. However, there is a limit to the dilution of the fuel mixture before the spark does not cause an external heat reaction in the cylinder. Currently, the mixing ratio limit is about 20: 1. Designers are striving to push the limits of this air-to-fuel ratio, which could theoretically be up to about 27: 1. Therefore, it is necessary to increase the limit of the mixing ratio.

In modern ignition systems, a transformer, known as an ignition coil, is mounted directly on each spark plug and is often referred to as a coil-on-plug (COP) ignition element. The size and weight of this element will affect the thermal properties. Coils operating at a high duty cycle must be large and heavy to prevent overheating. Conversely, low duty cycle operation makes the coil smaller and lighter. It is preferable to reduce the size of the coil of the coil-on-plug, because the restriction on engine packaging is reduced. Therefore, it is necessary to mount an element having the minimum size and weight on the spark plug.

<Structure of the Present Invention> According to the present invention, an improved ignition system capable of providing the necessary characteristics described above is provided. A solution to the above prior art problem is obtained by using new ignition system components. These components take advantage of various phenomena that occur during the explosion and ignition process.

It is believed that the ignition system has three distinct phases of discharge at the spark plug gap. It is a breakdown phase, an arc phase, and a glow phase in order from the beginning of the discharge. In the dielectric breakdown phase, a high voltage of about 10 kv is applied to the spark electrode, and a large current of 1,000 A or more flows within a short time of the order of nanoseconds (10 ^-9 seconds). Due to the extremely short phenomenon of the order of 10 ^-9 seconds, it has not been possible to obtain a measuring instrument having a sufficient dynamic response in the past, so that this current value cannot be measured accurately.
This current is called the ignition high-frequency current. In this breakdown phase, once a conductive path is formed in the gap, the discharge moves to the next arc phase, a low voltage is applied between the gaps, and a relatively small current flows for a relatively long time. Flows. In the last glow phase, both the voltage and the current are low. Many researchers, such as Marie and Bogle, who wrote a paper entitled "Ignition and Propagation of a Preflame in a Lean Methane-Air Mixture by the Three Phases of Ignition," reported a flame Tfront between the gaps. ) Spread during the breakdown phase, and have argued that the arc and glow phases not only contributed to the explosion, but were harmful because they erode the plug electrodes.

The ignition system of the present invention employs a pulse transformer system that operates in a manner distinctly different from conventional ignition coils. An ignition pulse transformer is mounted on the outer end of each spark plug. conventionally,
One coil provided high voltage for each of a number of spark plugs. In a conventional ignition system using a fly-back type transformer (ie, coil), energy is stored as a coil magnetic field, which increases through the current in the primary winding, and when the magnetic field disappears, the voltage in the secondary winding becomes zero. Become. Although flyback transformer coils have been used for decades, they are electrically inadequate. On the other hand, the main advantage of the pulse transformer in the present invention is that the spark plug is ignited in a shorter time of 50 .mu.s, since the inductance of the secondary circuit is greatly reduced, whereby the multiple firin is reduced.
g). Furthermore, because of the low impedance, partially dirty spark plugs can also be ignited. In a pulse transformer, the discharge energy is not stored as a magnetic field. The pulse transformer simply acts as a quick response step-up transformer and provides a secondary output in response to the voltage spike sent to the primary winding.

In an embodiment of the present invention, the insulation in the ignition system is used as a means for detecting the occurrence and timing of spark discharge and as a means for controlling the pulse transformer to minimize arc and glow phase discharge times. A ferrite toroidal detector that detects breakdown current is used.

Passien's law of the following equation is the breakdown voltage at the discharge point.
The relationship between Vb and the pressure P in the cylinder and the temperature T are defined (k is a constant).

As described above, the auto-ignition process is a method of detecting auto-ignition as a means of detecting auto-ignition, as evidenced by abnormally high pressure and temperature fluctuations occurring after top dead center (5 ° to 20 ° shaft angle). The ignition system applies a predetermined voltage, called the "hover" voltage, between the spark plugs during an engine operating cycle to facilitate auto-ignition pressure and temperature fluctuations. During auto-ignition, the pressure and temperature in the cylinder are related to the breakdown voltage according to Paciens' law, which is momentarily lower than the breakdown voltage for normal ignition, so that the discharge during that time Occurs only during conditions, not during normal ignition conditions.

Since the sensor according to the present invention has the above-mentioned toroidal detector and detects the breakdown current, it outputs the occurrence of the discharge as a signal. This signal is used to gradually retard the ignition timing for all or individual cylinders until the automatic ignition stops. The other is that in the routine, the ignition timing is advanced to cause automatic ignition again, and this automatic ignition is corrected again. Thus, at the threshold (start) of the automatic ignition, "swing" of the ignition timing occurs. Thus, by activating the spark plug in a predetermined operating window after top dead center, the spark plug acts as an automatic ignition detector,
It can detect much more sensitively than a conventional piezoelectric knocking sensor. The activation of the plug is not to contribute to the explosion process, but only to detect auto-ignition. With the pulse transformer of the present invention, the hover voltage can be adjusted to a desired value. This is difficult using conventional flyback transformer coils.

Since pressure and temperature characteristics of each cylinder are different for a certain internal combustion engine, it is desirable to calibrate each cylinder under a certain environment. Otherwise, when a certain hover voltage is used as an auto-ignition sensor, the auto-ignition may be erroneously indicated. After top dead center, during a section of the cylinder working cycle and before pressure and temperature fluctuations, a calibration is performed where the spark plug is activated through a series of voltages.

The voltage at which breakdown occurs during this calibration is used to adjust the hover voltage of the cylinder. Therefore, in accordance with the present invention, a total of three spark plug activation times occur within one piston stroke cycle. That is, a first discharge for causing a spark, a next second calibration discharge, and a third discharge for detecting automatic ignition.

As soon as the spark plug discharges, a "nucleus" is formed, a small sphere of ionized gas. This "nucleus" moves from where it was at the beginning of the plug gap as the fluid in the cylinder is turbulent. If the air-to-fuel mixture is high enough, the nuclei will induce an external heat reaction and grow rapidly, resulting in a spherical pre-flame. On the other hand, if the mixing ratio is extremely low, the hot nuclei are cooled by the surrounding fluid and become small, and disappear when moved from the plug, so that no effective energy can be extracted from the mixture in the cylinder. .

The mixture ratio of air to fuel when the internal heat / external heat reaction starts to occur is called the lean burn limit (lean burn limit) of the engine. The present inventor has ^proposed a microsecond (10 ⁻⁶⁾
It has been found that if the spark plug discharges many times in a short time, on the order of seconds, the lean burn limit will improve and a leaner mixture of fuels can be used. By rapidly burning the pulse with the plug, a series of nuclei are generated and blown and moved. Since the nuclei are close together, cooling from the surrounding fluid is minimized. Thus, the series of nuclei are kept in the cylinder for a long time, so that even leaner fuel mixtures can be burned. The use of a pulse transformer enables such rapid multiple combustion. This is not possible with conventional flyback transformer coils due to the large inductance of the secondary winding.

According to the invention, fast multiple ignition of the plug is achieved by detecting the breakdown current. This signal is used to shorten the discharge cycle, start the next ignition cycle, and cause multiple discharges in a short time.

Also, according to the present invention, the size and weight of the pulse transformer is minimized for structural and package efficiency. Essentially, using a pulse transformer minimizes size and weight. This is important. This is because the pulse transformer is located at the end of the spark plug where the weight of the pulse transformer affects the cantilever mounted on the plug due to engine and vehicle vibration. If the size of the pulse transformer is small,
Further, there is an advantage that the restriction on the engine package is relaxed. The size and weight of this type of pulse transformer is greatly affected by the thermal requirements. According to the present invention, the detection of the breakdown current is used as a means for cutting down the flow of the primary current to the spark plug coil, thereby reducing the duty cycle.
The next arc phase and glow phase are shortened without adversely affecting the combustion, since the breakdown phase of the discharge plays a useful role in initiating combustion. The inventor believes that a duty cycle on the order of 1% is possible with an ignition system that operates as described above. Such a low duty cycle minimizes the size and weight of the pulse transformer, thereby improving engine construction and packaging efficiency.

 Hereinafter, the present invention will be described more specifically with reference to the drawings.

FIG. 1 shows the voltage characteristics of a spark plug of an internal combustion engine. The voltage continues to rise until the time at which the discharge occurs, as shown by the solid line 10, and after the discharge, suddenly drops to a small value and shifts to the arc phase and the glow phase. The broken line 12 is the voltage between the electrodes when there is no discharge.

FIG. 2 shows current characteristics. 14 is a breakdown current, which occurs in a short time of the order of nanoseconds. As noted above, the ignition system according to the present invention comprises:
The detection of the dielectric breakdown current 14 is used for detection of combustion and timing control.

FIG. 3 shows the relationship between the cylinder pressure and the crankshaft position. Solid line 16 is the pressure during the normal combustion process. Cylinder pressure 16 continues to rise and peaks shortly after top dead center before decreasing with increasing cylinder volume. The broken line 18 indicates the fluctuation of the cylinder pressure during automatic ignition. This usually occurs at an angle of 5-20 ° after top dead center. This fluctuation is caused by an explosion reflected in the cylinder. During auto-ignition, fluctuations cause the cylinder pressure 18 to instantaneously rise to normal combustion pressure.
Lower than 16. This is detected in the present invention as an instantaneous decrease in the breakdown voltage.

FIG. 3 also shows three spark plug activation times according to the present invention. Pulse voltage 20 is applied before top dead center to initiate the combustion process. The pulse voltage 22 is provided at or shortly after top dead center as a means of calibrating the automatic ignition detection system. Pulse voltage 22
Has a sawtooth waveform that rises until discharge occurs and decreases during discharge. Thus, the total pulse width of the pulse voltage 22 corresponds to the cylinder pressure according to Passien's law. The breakdown voltage of pulse voltage 22 is used to calibrate the system to accurately detect auto-ignition while allowing for variations between cylinders. This calibration is
This is done before the effects of auto-ignition appear on the breakdown voltage.

The pulse 24 detects the auto-ignition by applying a hover voltage, which is adjusted so as to cause a discharge when the cylinder pressure becomes lower than the normal combustion pressure and the cylinder internal temperature rises, to the plug electrode.

FIG. 4 is a block diagram of the ignition system 30 of the present invention. The ignition system 30 receives an input signal from an engine timing transducer 34, an engine timing
Controller 36 and vehicle oxygen sensor module
It has an onboard ignition controller microprocessor 32 received from 38. DC power supply 40 is powered by vehicle battery 42 and provides power to each element of the system. The microprocessor 32 sends an output signal to a pulse transformer 44 mounted on a spark plug driven by a driver 46.

Engine timing transducer 34 provides pulse signals from magnetic or optical sensors that detect the position of the crankshaft or camshaft to output the crankshaft position. This signal is used for ignition timing and rotation speed measurement.

The engine timing controller 36 is driven by the microprocessor 32 and receives signals from the timing transducer 34 to control parameters such as cooling water temperature, throttle position, ambient air temperature, manifold pressure, and load detection. To set a preferable ignition timing. Also, a signal indicating automatic ignition is received from the microprocessor 32. As described above, the timing controller 36 delays the timing until the automatic ignition is detected, and then advances the timing again.
Keep the engine at the start of automatic ignition. This causes the ignition system to be in the state of initiating automatic ignition for a particular engine using parameters that are present at all times.

The vehicle oxygen sensor module 38 detects oxygen in the exhaust gas of the engine and inputs the air to fuel ratio to the microprocessor 32. The oxygen sensor is typically a zirconium diode mounted in the engine exhaust manifold. The signal from the sensor module 38 is
Used to control the fuel injection system.

The microprocessor 32 receives the above signal and drives the spark plug through the driver 46 and the pulse transformer 44. In FIG. 5, the pulse transformer 44 and the driver 46 are shown in detail. FIG. 5 is for a four-cylinder engine, with a series of four pulse transformers.
44 and driver 46 are shown. One of these is indicated by 48 and is enclosed in dashed lines. The other three have the same configuration. The driver 46 receives a 200 V DC signal from the power supply 40 and is therefore physically separated from the pulse transformer 44. The driver 46 is applied with a voltage of 200 V DC along the plus bus 50 and the ground bus 52. An ignition signal from microprocessor 32 is sent through connector 54 along lines 56, 58, 60, 62 for each cylinder. Line 62 is for the driver and pulse transformer coupling circuit 48. Line 59 is a common low voltage line for power supply 40.

Ignition signal VMOS type switching transistor 64
, Interface transformer 66 with electrostatic shield
Sent through. Diodes 68 and 70 are for circuit protection,
The diode 72 is used for clamping. When the ignition signal is sent along line 5, a high voltage spike is sent along line 74 to pulse transformer 44 and the primary winding of the pulse transformer grounded via line 78.
Through 76, a voltage is applied. The current flowing through the primary winding 76 includes a high voltage pulse through the secondary winding 80. The voltage induced in the secondary winding 80 is applied between the spark plug gap 82.

According to the present invention, an element for detecting a breakdown current is provided. Since this current flows only for a very short time, the high impedance of the return path to ground 84 makes it difficult to detect the current. Therefore, as another return path, a spark plug shield electrically connected to the bottom of the spark plug and connected to ground line 88
86 are provided. The signal on line 88 is
It passes through the earth bus 52 through the beads 90. A voltage is induced in the loop 92 by the high frequency large current signal. The output of loop 92 is about 50V, a ^10-9 second pulse. A full-wave rectifying bridge 94 rectifies this induced voltage to form lines 96, 98
And to the microprocessor 32 through the connector 54.

FIG. 6 shows a pulsed lamp attached to the spark plug 102.
FIG. 4 is a sectional view of a transformer 44. The pulse transformer 44 includes a primary winding 76 and a secondary winding 80, and a connector 106 (FIG. 5).
And a terminal 104 for electrical connection with the terminal. Terminal post 108 is connected to post 110 of spark plug 102 and to transformer post 105. Post 108
There is a grip socket 107 at the bottom for mating with the plug post 110. Rubber boot 112 with spark plug 10
Combined with the outer ceramic surface of 2, the pulse transformer 44
I support. The plastic body 109 is pulsed
The transformer 44 is mounted and supported. A shield 86 surrounds the pulse transformer 44, one end of which is a spark plug 102
To hold the legs 114.

7 and 8 show the microprocessor 32 at various phases of the ignition operation for one of the four cylinders.
3 shows an output control signal from the control unit. FIG. 7 shows a series of pulse trains generated to initiate ignition of the air-fuel mixture in the cylinder before top dead center. Square wave pulse 116 represents the control signal output from microprocessor 32 along one of lines 56-62. This signal causes the primary and secondary voltages of the pulse transformer 44 to rise with time, such as a sawtooth pulse 118. Pulse 118 represents the voltage at the spark plug gap. The secondary voltage, which is the pulse 118, rises to the discharge point, and after the discharge, falls when it shifts to the arc phase and the glow phase.
The waveform of the pulse 116 is
The size of the pulse width 120 and the pulse period 122 are adjusted and determined.

According to a typical experimental example of the pulse transformer 44, the time during which the primary current flows is shorter than 6 μs. When a breakdown occurs, it is detected by loop 92 through ferrite bead 90 and 1 by switching transistor 64.
The next current is turned off. Thereafter, the primary current flows through clamp diode 72 and continues to flow for up to 60 μs. loop
Using the output from 92, the ignition interval is 40-60 μs
Can be kept short. With this quick response, for example, 7
Multiple ignitions such as pulses are possible. As described above, such multiple ignition allows the use of a leaner mixture of fuels. The inventor, for one engine,
It has been found that if the pulse period is 100 μs or less, the mixture ratio can be made thinner.

By monitoring the pulse width of the control signal 116,
A measurement of the breakdown voltage is made. A dirty plug or pre-ignition results in a low breakdown voltage, whereas an open circuit results in a very high breakdown voltage. Therefore, the pulse of FIG.
By measuring the dielectric breakdown voltage of 20, the abnormal ignition condition can be detected.

In the next phase of spark plug activation, a signal is sent to the pulse transformer 44 at a position after the crankshaft is about 5 degrees from top dead center. At this point in the cycle,
There is no autoignition originally, this signal is provided to detect cylinder pressure before autoignition occurs. FIG. 8 is similar to FIG. 7 in that it shows the signal from the microprocessor 32 and the voltage that the signal provides between the spark plug and the gap. Square wave pulse 124
Produces pulse 22 as an interrogation signal. The control signal 124 is sent and then turned off until the high frequency current is detected by the ferrite beads 90. Due to the rising curve characteristics of the sawtooth pulse 22, the duration of the square pulse 124 is a function of the breakdown voltage. That is, the pulse
The phase shift between the tip of 124 and the occurrence of breakdown relates to the breakdown voltage and cylinder conditions. If the cylinder pressure is above the average (or if the cylinder temperature is below the average), pulse 22 must rise to a higher voltage value as shown by dashed line 128 before discharge occurs.
Conversely, if the cylinder pressure is lower than the average value but the cylinder temperature is higher than the average value, it is detected by shortening the pulse width of the pulses 22 and 124.

In the last phase, the "hover" phase, a series of square wave control signals 130 are output from the microprocessor 32 to generate a corresponding sawtooth pulse train 24. As described above, this hover voltage is used for detection of automatic ignition. If the cylinder pressure is normal without auto ignition,
The maximum hover voltage across the plug gap is not sufficient to cause a discharge. However, when auto-ignition occurs, rapid fluctuations in pressure and temperature in the cylinder will momentarily reduce the breakdown voltage, causing a discharge, which is detected by ferrite beads 90. This discharge is then used to delay spark timing.

As mentioned above, the interrogation pulse 22 is used to calibrate the appropriate hover voltage value of the pulse 24. Therefore, when the cylinder operates normally at a higher than average pressure, the maximum value of the hover voltage is increased to allow detection of pressure fluctuations caused by auto-ignition. Conversely, if the normal pressure is lower than the average, the hover voltage 24 will be low, preventing a point-in-time ignition instruction to occur during normal ignition operation. For calibration, the ratio of the pulse width of pulse 124 to pulse 130 is used. The higher the breakdown voltage in the interrogation pulse, the higher the value of the hover voltage 24. FIG. 8 shows pulse 12
When the pulse width is increased, as in FIG. 6, the increased control signal 132 results in a higher hover voltage 134. During the hover phase, during normal combustion without discharge, the voltage between the plug and the gap, as in pulse train 24,
It gradually disappears.

FIG. 9 shows a flowchart of the scanning routine 138. A key pad entry is provided to adjust for variations made in this routine. Block 14
Since 0 determines whether the cylinders are synchronized, an ignition command is suitably output from the engine timing transducer 34. Also, at block 140,
It also detects whether the engine is running. Block
At 142 and 144, determine whether the engine has stopped and measure the engine speed. The value of 1000 RPM in block 144 is an example of a low speed at which the interrogation / hover signal ends, at which no automatic ignition occurs. The hover calibration block 146 determines the timing of applying the hover voltage a predetermined number of times after the top dead center, and the block 148 terminates the application of the hover voltage at a position 35 ° after the top dead center.

FIG. 10 shows a pulse start and delay control routine 150 of the pulse timer in the microprocessor 32. This determines the pulse width 120 and starts a delay timer that determines the pulse period 122 for control pulses sent from the microprocessor 32 to the pulse transformer 44 during the ignition, interrogation, and hover cycles.

FIG. 11 shows a pulse control routine 154 for determining the width 120 and the period 122 of the hover phase pulse. The pulse width and delay timer of the input from the engine timing transducer 345 are respectively blocked.
It starts like 156,158. Block 160 is calibrated at 35 ° after top dead center and input to block 148 in FIG.

FIG. 12 shows the pulse width routine 162, which shows a pulse timer that starts under software control and stops by software or an external high frequency current signal. In this routine, the pulse width of the interrogation pulse is
Used at 164 to determine the hover pulse width.

FIG. 13 shows an ignition hover phase control routine 172. This routine has two blocks 174, 176, each with an ignition phase related to the hover phase. For each block, a pulse timer and a delay timer are started to determine the appropriate pulse width and pulse period.

Although the above description has been made with reference to preferred embodiments of the present invention, the present invention may be modified without departing from the scope.

[Brief description of the drawings]

FIG. 1 is a characteristic graph of a discharge voltage at a spark plug,
FIG. 2 is a characteristic graph of a breakdown current, FIG. 3 is a graph of a cylinder pressure (upper diagram) and a pulse voltage (lower diagram) with respect to a crankshaft position, FIG. 4 is a block diagram of an ignition system of the present invention, and FIG. The figure shows a detailed circuit diagram of the pulse transformer and the driver, FIG. 6 is a cross-sectional view of the pulse transformer, and FIG. 7 shows the control signal, secondary voltage,
Each pulse train of the high-frequency current, FIG. 8 shows the pulse waveforms of the control signal (upper figure) and the secondary voltage (lower figure), and FIGS. 9 to 13 show each routine controlled by the microprocessor of the ignition system of the present invention. It is a flowchart. 30 Ignition system; 32 Microprocessor; 44 Pulse transformer; 46 Driver; 82 Spark plug gap; 102 Spark plug.

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Claims (5)

(57) [Claims] 1. A pulse transformer connected to a spark plug and having a primary winding and a secondary winding, and applying a voltage signal to a primary winding of the pulse transformer to apply the voltage signal to the spark plug. Driver means for inducing a high voltage signal to be applied to the secondary winding, controller means for applying a control signal to the driver means to generate a voltage on the secondary winding, and detecting occurrence of discharge at the spark plug And a discharge detection means for providing a discharge signal to the controller means to control the operation of the controller means; and a timing means for detecting a position of the piston and providing a timing signal, wherein the controller means Applying a predetermined maximum hover voltage to the spark plug during the cylinder actuation cycle after the point, wherein the hover voltage is such that the discharge of the spark plug is It is applied at a value such that it occurs if there is automatic ignition in the cylinder, but does not occur if normal combustion occurs in the cylinder.The discharge detection means gives a signal indicating the occurrence of automatic ignition, and the piston detects the top dead center of the piston. An ignition system for an internal combustion engine that detects the presence of abnormal ignition due to pressure and temperature fluctuations that occur later in the cylinder. A timing means for detecting a piston position and providing a timing signal; an ignition spark plug having an electrode forming an air gap in a cylinder; and a power supply for applying a voltage to the air gap of the spark plug. Means for receiving a timing signal and controlling the power supply means to apply a predetermined maximum value of the hover voltage to the spark plug gap during the cylinder operation cycle after the top dead center; Detects the occurrence of discharge in the spark plug gap by means of the controller means, which applies a value between the plugs if auto-ignition occurs in the cylinder but does not occur during normal combustion, and the hover voltage. And a discharge detection means for providing a signal indicating the presence of auto ignition, the pressure occurring in the cylinder after top dead center. And the fluctuation of the temperature, and detects the presence of the auto-ignition is not a normal combustion, ignition system for an internal combustion engine. 3. A timing means for detecting a piston position and providing a timing signal; an ignition spark plug having an electrode forming an air gap in a cylinder; and a primary winding directly bonded to the spark plug. And a secondary winding, the secondary winding being connected to the electrode of the spark plug, and a voltage pulse being sent to the primary winding of the pulse transformer in response to a control signal. A driver circuit for applying a high voltage signal to the electrode of the plug, a ground return conductor connected between one of the spark plug electrodes and ground, and a current detector for detecting a current in the conductor. A spark discharge detector for detecting a short-time large current generated at the beginning of the ground between the spark plug gaps, and receiving a timing signal to provide a control signal to a driver circuit. , Into the cylinder operating cycle after the top dead center, spark
A predetermined maximum value of the hover voltage is applied between the plug gaps, and the maximum value of the hover voltage is set so that the discharge between the spark plugs occurs when the auto-ignition occurs in the cylinder but does not occur during normal combustion. And controller means for adjusting the ignition timing according to the output signal of the spark discharge detector. The fluctuation of the pressure and temperature occurring in the cylinder after the top dead center causes the automatic ignition which is not normal combustion to occur. An ignition system for an internal combustion engine, characterized by detecting the presence. 4. The system according to claim 1, wherein said controller means operates near the start of the automatic ignition by delaying the ignition timing when detecting the automatic ignition, and advancing the ignition timing when not detecting the automatic ignition. The ignition system as described. 5. A timing means for detecting a piston position and providing a timing signal; an ignition spark plug having an electrode in a cylinder separated by an air gap; and a primary winding mounted directly on the spark plug. And a secondary winding, the secondary winding being connected to the electrode of the spark plug, and a pulse voltage being sent to the primary winding of the pulse transformer according to a control signal. A driver circuit for applying a high voltage signal to the spark plug electrode, a ground return conductor connected between the spark plug electrode and ground, and a current detector for detecting a current in the conductor, A spark discharge detector for detecting a large current flowing only for a short time at the beginning of an arc between the spark plug gap, and receiving a timing signal to send a control signal to a driver circuit. Gives a question control signals between the piston operating cycle auto-ignition does not normally occur, the question control signals the spark
Causing an interrogation pulse voltage in the plug gap and increasing the interrogation voltage to reach a breakdown voltage at which discharge occurs between the gaps, the breakdown voltage affecting the pressure temperature conditions to which the spark plug electrode is exposed. And measuring the phase difference between the leading edge of the interrogation control signal indicating the current condition and the breakdown current, and furthermore, after the top dead center, during the cylinder operating cycle, the predetermined maximum value. A hover voltage is applied between the spark plug gaps, the hover voltage being applied to a value such that a discharge between the spark plugs occurs if there is auto-ignition in the cylinder, but does not occur during normal combustion; Controller means for adjusting the value of the hover voltage according to the phase difference, thereby adjusting the hover voltage according to the interrogation pulse breakdown voltage. The pressure and temperature fluctuations that occur in the cylinder after top dead center to symptoms, to detect the presence of auto-ignition is not a normal combustion, ignition system for an internal combustion engine.