JPS6059432B2 - Leak state detection method and device in high voltage circuit of internal combustion engine ignition system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for detecting a leak state in a high voltage circuit that constitutes an ignition circuit of an internal combustion engine or the like.

The ignition circuit of an internal combustion engine using the high voltage ignition method generally has a high voltage circuit consisting of an ignition coil, a coil cord, a distributor, a plug cord, and a spark plug. The high voltage of several 1 OKV generated from the secondary output terminal is supplied to the distributor through the coil cord, and distributed to each cylinder of the engine by the rotation of the distributor, and the spark plug of each cylinder is supplied through the plug cord. is supplied to the spark plug to generate a spark.

The high voltage circuit is arranged to ensure high insulation from the engine body, ignition circuit system, etc., and to prevent the high voltage transmitted to the high voltage circuit from leaking to the engine body, etc. For example, in an ignition coil that generates high voltage, the primary coil on the low voltage side and the secondary coil on the high voltage side that make up the ignition coil are shielded with resin or the like with excellent insulation, and furthermore, the secondary coil The output terminal and the ignition coil body have a structure that has sufficient insulation. Further, the coil cord and the plug cord are coated with rubber or the like having sufficient insulation properties for the core wire carrying high voltage. Furthermore, the distributor includes a rotatable center electrode section for distributing the high voltage supplied by the coil cord from the secondary output terminal of the ignition coil to each cylinder, and a plurality of electrodes arranged for each cylinder. The outer electrode portion is integrally molded with a highly insulating resin material, and these electrode portions have a structure that ensures sufficient insulation from the outside. Also, regarding spark plugs,
The center electrode of the spark plug to which the high voltage is supplied is integrally molded with a highly insulating insulator or the like to ensure sufficient insulation from the engine body. Therefore, these high voltage circuit sections are
By using a highly insulating structure, the high voltage of several tens of kilovolts output from the secondary output terminal of the ignition coil is transmitted to the ignition plug without leaking to the engine body or the like. However, some of the elements that make up the high voltage circuit may become pinholes due to aging or damage. When holes or cracks occur, there is a problem in that high voltage leaks to the outside from the defective portion.

FIG. 1 shows the main parts where the high voltage generated from the ignition coil causes voltage leak in the high voltage circuit of an engine using the high voltage ignition method.

No. In Figure 1, one end CCl of a coil cord CC is connected to the secondary output terminal of the ignition coil ■G, and the coil cord CC
The other end CC2 is connected to the center electrode of the distributor cap DC, one end PCl of the plug cord PC is connected to the outer electrode of the cap DC, and the other end PC of the plug cord PC is connected to the center electrode of the distributor cap DC.
2 shows the state where it is connected to the spark plug PL. According to the above connection relationship, the high voltage of more than 10 KV generated from the secondary output terminal of the ignition coil IG is transmitted through the coil cord CC.
Rotor R disposed in cap DC of distributor DB
In a multi-cylinder engine, the rotor RO is connected to the drive shaft of the engine and rotated, thereby A high voltage is distributed to the outer electrodes in the distributor DB corresponding to each cylinder. The high voltage distributed to each cylinder by the distributor DB is applied to the spark plug PL connected to each plug cord PC via the plug cord PC for each cylinder, and electricity is applied to the spark plug PL. Generates a spark to ignite the gas mixture in the engine cylinder.
There are some that burn to run the engine. In the ignition circuit consisting of the above connections and operations,
Voltage leakage is likely to occur in the parts B, C, and D. That is, if a crack or the like occurs in part A due to damage or deterioration of the coil cord CC, a voltage leak occurs to the vehicle body part E or the like adjacent to the coil cord CC. In addition, in part B, if the surface of the distributor cap DC made of a highly insulating resin material becomes wet or soiled,
Voltage leakage occurs between the outer electrode of the cap DC and the distributor DB body made of a metal material. Furthermore, if cracks occur in section C due to damage or deterioration of the plug cord PC, the air cleaner A adjacent to the plug cord PC
Voltage leakage occurs in the C and the engine body (not shown). In addition, in section D, if the surface of the highly insulating insulator of the spark plug PL is wet with water or soiled, or if a crack occurs in the insulator, the engine body EB or the spark plug PL
voltage leak to the ground side of the If these voltage leaks occur in some of these parts while the engine is running, it will not only induce a misfire in the engine and cause the engine to malfunction, resulting in extremely large damage to the engine, but also cause combustible substances such as gasoline. In engines that use high-temperature fuel, the fuel may ignite due to the generation of sparks due to voltage leakage, leading to a fire, resulting in an extremely dangerous situation in automobiles.
Therefore, it is extremely important to efficiently supply the high voltage of tens of kilograms generated from the ignition coil IG to the ignition plug PL without causing a voltage leak in the middle of the high voltage circuit. , the coil cord CCl distributor DBl plug cord PCI ignition plug PL, etc. that transmit the high voltage must be managed so as to always maintain a normal state. Conventionally, voltage leaks in these high voltage circuits are
The surroundings of the high-voltage circuit are darkened, and a worker visually determines the discharge light caused by the spark discharge caused by the voltage leak, or a worker auditorily determines the discharge breaking sound caused by the spark discharge. Was.

According to these conventional methods, in the case of a minute voltage leak, the discharge light due to the voltage leak becomes weaker and the discharge breakdown sound also becomes smaller, so that it can be used under noisy conditions during engine operation or under normal work lighting. Then, there was a problem that it was extremely difficult to judge. The present invention has been made to solve the above-mentioned conventional drawbacks, and is a voltage leak detection method and device in a high voltage circuit section of an internal combustion engine ignition system that can quantitatively measure voltage leaks without relying on the sensibility of the operator. The purpose is to provide

In order to achieve the above object, a first invention according to the present invention provides a high-voltage cord and a coil cord, each comprising a coil cord connected to an ignition coil of an internal combustion engine ignition system and a plurality of plug cords each connected to an ignition plug. While the high voltage circuit section is installed in the internal combustion engine, the ignition controller is connected to the high voltage circuit section equipped with the distributor disposed between the plug cord and the high voltage circuit section.
The high voltage circuit portion is electrically insulated between the secondary side terminal of the coil and the coil cord, the engine is driven to crack, and a high voltage synchronized with compression top dead center is applied to the coil cord from the outside. The present invention is characterized in that a high voltage is applied in a distributed manner to the parts, and a leak signal based on a leak phenomenon that occurs in the high voltage circuit section when the high voltage is applied is detected.

Further, in order to achieve the above object, a second invention according to the present invention provides a high-voltage cord and a coil cord, each comprising a coil cord connected to an ignition coil of an internal combustion engine ignition system and a plurality of plug cords each connected to an ignition plug. A means for electrically insulating between the coil cord and the secondary terminal of the ignition coil in a high voltage circuit section equipped with a distributor disposed between the cord and the plug cord, and detecting the top compression position of the engine. Based on a top dead center sensor and a signal output from the top dead center sensor, a top dead center signal synchronized with the compression top dead center position and two sets of pulse signals synchronized before and after the top dead center signal are generated. a high-voltage power supply that generates a pulsed high voltage synchronized with the top dead center signal; a high-voltage cable that connects the high-voltage power output to the high-voltage cord; A detection circuit that detects the maximum value of the high voltage power supply output according to two sets of pulse signals, a determination circuit that compares and determines the output signal level of the detection circuit with an arbitrarily settable determination level, and the determination circuit. It consists of a display circuit that displays output determination results, and is characterized in that it detects a leak state when a high voltage is distributed and applied while the engine is cranking.

The principle of the present invention will be explained below.

FIG. 2 shows a cross-sectional view of a high voltage cord such as a coil cord CC or a plug cord PC that constitutes a high voltage circuit section of a typical vehicle. In this high-voltage cord, the periphery of the conductor C1, which is the core wire, is covered with highly insulating rubber C2, which is usually 3 meters thick, to prevent the high voltage of several tens of kilograms applied to the conductor from leaking to the outside. ing. However, if cracks or pinholes C3 occur in these high-voltage cords due to age-related deterioration or damage to the insulation coating, voltage leaks from the damaged portions to the outside, that is, to the nearby engine, body, ground, etc. E. Therefore, a pinhole is made in a part of the high-voltage cord, and the distance between the outer diameter of the high-voltage cord and the ground, that is, the air gap length, is set as D, and when a high voltage is applied to the conductor of the high-voltage cord and a voltage leak occurs. FIG. 3 shows the relationship between the gap length D and the leakage voltage. In FIG. 3, a solid line a indicates a case where the high voltage cord surface is dry, and a broken line b indicates a case where the high voltage cord surface is wet with water.For example, in the solid line a, the air gap length is In the case of 5wn, the leakage voltage is approximately 19KV, and in the case of air gap length 1-, the leakage voltage is approximately 30KV.Therefore, in the above-mentioned normal normal vehicle ignition circuit, the secondary of the ignition coil IG From coil IG2, 20K
■Since a higher voltage than above is generated, if the judgment level of the judgment circuit is set to the equivalent of 18KV, it will be approximately 5m! It can be seen that voltage leaks can be determined with an air gap length of . Furthermore, by setting the judgment level of the judgment circuit according to the value of the high voltage output from the ignition coil IG with reference to FIG. 3, it is possible to arbitrarily judge the magnitude of the voltage leak. Not even. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the first embodiment of the present invention, the high voltage output from the leak state detection device 1 is applied to the coil cord CCl distributor DB1 plug cord PC and the spark plug PL via the high voltage cable 2.

At this time, a spark discharge occurs at the electrode of the spark plug PL, but
This detects a voltage leak with a leak voltage lower than the discharge breakdown voltage of the spark plug PL. However, the spark plug PL
The discharge breakdown voltage of the spark plug PL is approximately 4KV when the electrode gap of the spark plug PL is normal (usually 0.8 to 1.0Tnm) and at atmospheric pressure and room temperature.
Only voltage leaks in the high voltage circuit section caused by leakage voltages below are detected. Therefore, it is insufficient in terms of performance to apply a high voltage to the high voltage circuit section while the ignition plug remains under atmospheric pressure and measure voltage leakage.
In the method according to the first embodiment of the present invention, the engine is cranked and the high voltage is applied to the spark plug PL in synchronization with the maximum compression of the engine and cylinder, that is, the top dead center of the engine. As a result, the discharge breakdown voltage of the spark plug PL at the top dead center can be increased to 1 K■, and a voltage leak due to a leakage voltage of 1 K■ or less can be sufficiently detected. FIG. 4 shows a block diagram of the leak state detection device 1 based on the first embodiment of the present invention and the connection relationship with the vehicle to be measured.
A specific electric circuit based on the block diagram of FIG. 4 is shown in FIG. 6, and time charts of signal waveforms at various parts in FIGS. 4 and 5 are shown, respectively.

The voltage leak detection device 1 according to the present embodiment is as follows. As shown in FIG. 4, a top dead center sensor 10 and a top dead center signal generation circuit 11
．． It is comprised of a high voltage generation circuit 1 that generates a high voltage, a detection circuit 3, a determination circuit 4, and a display circuit 5.

As shown in FIG. 5, the top dead center sensor 10 is composed of a magnetic core 1000 made of a magnetic material and a coil 1001 wound around the magnetic core 1000. A current line is included in which the battery BA and the starter ST are connected in series.

In this case, for example, by making the magnetic core 1000 have a clamp type structure, it can be easily clamped to the current line. Note that this top dead center sensor 10 is connected to the battery BA during engine cranking drive.
Starter ST that cranks and rotates the engine from
The top dead center signal is detected by utilizing the fact that the maximum value of the cranking current flowing in each cylinder matches the compression top dead center of each cylinder, but the top dead center sensor is limited to this. For example, it is also possible to detect the top dead center signal by installing means such as an optical pickup or an electrode pickup on the engine, crank, pulley, and engine body. The top dead center signal generating circuit 11, as shown in FIG. ), a Schmitt circuit consisting of a resistor 1105, a diode 1106, and an operational amplifier 1107, an integrated circuit having a monostable multivibrator function (hereinafter abbreviated as 1C) 1108, a capacitor 1109, and a resistor 1110.
A first monomulti circuit consisting of ICllll, which also has a monostable multivibrator function, and a capacitor 1
112 and a resistor 1113, a half-wave rectifier circuit consisting of a diode 1114 and a resistor 1115, and switching elements such as diodes 1116, 1117, operational amplifiers 1118, 1122, resistors 1119, 1120, capacitor 1121, and FET. A peak hold circuit consisting of 1123 and resistors 1124 and 1125
, 1126, 1127 and an operational amplifier 1128, and a comparator consisting of resistors 1129, 1130, a diode 1131, and an operational amplifier 1132.

The high voltage generating circuit 1 includes resistors 110, 111, 113, 114, a variable resistor 116, as shown in FIG.
Transistors 112, 115 and step-up transformer 117
It is operated by the rectangular wave output (Fig. 6g) of the top dead center signal generating circuit 11, and generates a pulsed high voltage of several tens of KV in synchronization with the rising edge of the rectangular wave signal. Has a function.

The output of this high voltage generating circuit 1 is electrically connected to one end CC of a coil cord CC via a high voltage cable 2. The detection circuit 3 includes a resistor 3 as also shown in FIG.
00, 301, a noise limiter consisting of a resistor 302, diodes 306, 307, an amplifier circuit consisting of resistors 303, 304, 305 and an operational amplifier 308, diodes 310, 311, and a resistor 312.
, a peak hold circuit consisting of a capacitor 313, a gate element 317, and operational amplifiers 309 and 315, and a sample hold circuit consisting of a gate element 318, a resistor 319, a capacitor 320, and an operational amplifier 321.

A high voltage signal (h in FIG. 6) is input from the output end of the high voltage generation circuit 1 to the input end of the resistor 300 of the detection circuit 3, and the maximum value of the high voltage signal h is at the top dead center. It is held in the peak hold circuit section in synchronization with the top dead center signal (Fig. 6g) output from the signal generation circuit. That is, since the high voltage signal h is generated from the high voltage generation circuit 1 in synchronization with the rising edge of the top dead center signal g, a gate element 317 such as an FET is provided in the peak hold circuit section, By operating in response to the reset signal d input from the point signal generation circuit 11, the maximum value of each high voltage signal h is held in synchronization with the cranking drive rotation speed period of the engine. The hold output of the peak hold section (FIG. 6 1) is converted into a DC signal (FIG. 6 j) by the operation of the next-stage sample and hold circuit. That is, the gate element 318 such as the FET of the sample and hold circuit is
By driving the hold signal 1 by a sampling signal (FIG. 6c) inputted from the top dead center signal generation circuit 11 and holding the hold signal 1 in synchronization with the cycle of the top dead center signal g, The high voltage signal h is converted into a DC signal j that changes every cycle of the top dead center signal g in proportion to the maximum value. This DC signal j is input to the determination circuit 4 at the next stage. The determination circuit 4, as shown in FIG.
It consists of resistors 400, 401, 403, a diode 402, and an operational amplifier 404, and the output of the detection circuit 3 is
It has a comparison function of outputting an output of ゛゜1゛ when the comparison voltage inputted through the resistor 403 becomes lower than 2.

The output of the determination circuit 4 (FIG. 6k) is input to the input terminal of the display circuit 5. The display circuit 5, as shown in FIG.
When the output of the judgment circuit 4 reaches "1", the light emitting diode lights up, and the output of the detection circuit 3 is detected by the analog meter 505. In this embodiment, the output of the high-voltage voltage generating circuit 1 is conductively connected to one end CCl of a coil cord CC, which is a high-voltage circuit element of the vehicle, via a high-voltage cable 2.

Further, the ground 6 of the voltage leak detection device 1 is connected to the engine,
Connected to the body and ground. Furthermore, in the ignition circuit section of the vehicle, the connection point between the output terminal of the secondary coil IG2 of the ignition coil IG and one end CCl of the coil cord CC is electrically insulated. The action will be explained below.

In the above connection relationship, the engine is cranked by operating the engine key SW, etc., and the battery BA is
When cranking current 1c flows from to starter ST,
A magnetic flux is generated on the outer periphery of the current line, and the magnetic flux is absorbed into the magnetic core 1000 that forms a closed magnetic path in the clamped state, and a voltage is induced in the coil 1001 wound around the magnetic core 1000. The cranking current signal (FIG. 6a) is detected. The cranking current signal a detected by the top dead center sensor 10 is input to the input end of the input resistor 1100 of the LPF circuit section of the top dead center signal generating circuit 11. The LPF circuit section functions to remove high frequency components such as starter ST brushes and noise contained in the cranking current signal a. The output of the LPF circuit section is input to the input terminal of the input resistor 1105 of the Schmitt circuit section, the cranking current signal a is converted into a rectangular wave signal (FIG. 6b), and the rectangular wave signal b is 1st
and is input to the second monomulti circuit section. The first mono-multi circuit generates a pulse signal (FIG. 6d) with a constant time width determined by the time constant of the capacitor 1109 and the resistor 1110 in synchronization with the rising edge of the rectangular wave signal b.
occurs. Furthermore, the second monomulti circuit generates a pulse signal (FIG. 6c) with a constant time width determined by the time constant of the capacitor 1112 and the resistor 1113 in synchronization with the falling edge of the rectangular wave signal b. Occur. Next, the LP
The output of the F circuit is the diode 1114 of the half-wave rectifier circuit.
is input to the input terminal of the cranking current signal a, and only the positive direction component of the cranking current signal a is passed through and input to the peak hold circuit section. The peak hold circuit section functions to hold the maximum value of the positive direction component of the cranking current signal a, and the pulse signal d output from the first monomulti circuit section and the peak hold circuit section hold the maximum value of the positive direction component of the cranking current signal a. The cranking current signal a is held in each cycle by the action of the switch element 1123 connected to the peak hold circuit, and the peak hold circuit section outputs the Hall F signal (Fig. 6 e) in each cycle. The signal is then input to the input end of the input resistor 1124 of the next-stage differential amplification circuit. Furthermore, the cranking current signal of the positive direction component of the half-wave rectifier circuit section is simultaneously input to the input terminal of another input resistor 1125 of the differential amplification circuit section. Therefore, the peak hold circuit output e and the positive direction component of the cranking current signal are simultaneously input to the differential amplification circuit section, and a differential operation is performed on both signals, resulting in a difference output (FIG. 6, f). ), which is input to the input end of the input resistor 1129 of the next-stage comparator circuit section. In the comparator circuit section, a comparison voltage +E1 inputted via another input resistor 1130 and the difference output f are compared,
A rectangular pulse signal, that is, a top dead center signal (FIG. 6g) is generated and input to the next stage high voltage generation circuit 1. Also,
Pulse signal d output from the first monomulti circuit
is input to the detection circuit 3 as a sampling signal of the sampling and hold circuit section of the detection circuit 3, and the pulse signal c output from the second monomulti circuit is
Similarly, it is input to the detection circuit 3 as a reset signal for the peak hold circuit section of the detection circuit 3. The top dead center signal g
is input to high voltage generation circuit 1. and in synchronization with the rising edge of the top dead center signal g, a pulsed high voltage (Fig. 6h)
The high voltage is applied to the high voltage circuit section of the vehicle via the high voltage cable 2.

Therefore, the high voltage generating circuit 1 operates according to the top dead center signal g, and the high voltage generating circuit 1 operates according to the top dead center signal g. In synchronization with the top dead center timing of signal g,
Since a high voltage is generated, the high voltage is applied to the coil cord CCl distributor D at maximum compression of the engine cylinder.
It is applied to the high voltage circuit section consisting of the B plug cord PC and the spark plug PL. The detection circuit 3 detects the maximum value of the high voltage applied to the high voltage circuit section or the leakage voltage based on the voltage leak generated within the high voltage circuit section, and converts it into a DC signal (the first one). The converted signal is output as shown in FIG. 6 (j) and input to the next stage determination circuit 4. The determination circuit 4 determines only the leakage voltage based on the voltage leakage based on an arbitrarily set determination level, and outputs a determination signal (
k) in FIG. 6 is output, and the next stage display circuit 5 displays the voltage leak. In this embodiment, a high voltage is applied to all the high voltage circuit sections consisting of the coil cord CCl distributor DBl plug cord PCl spark plug PL, and voltage leaks in the high voltage circuit sections are detected. A high voltage is also applied to the spark plug PL to measure voltage leaks, and voltage leaks caused by stains or cracks on the insulator surface of the spark plug PL can also be detected.

In the leak state detection device 1 based on the first embodiment of the present invention described above, the coil cord CCl distributor DBl plug cord P constituting the high voltage circuit section of the vehicle is
With all C and spark plug PL installed in the vehicle,
By cranking the engine and applying a high voltage to the high voltage circuit section at the compression top dead center of the engine, voltage leakage occurs at multiple plug cords, such as PCl spark plugs PL, especially in multi-cylinder engines. can be detected and measured efficiently.

However, in the leak state detection device 1, when the engine is cranked and the mixed gas flows into the engine cylinder from the carburetor, the high voltage applied from the leak state detection device 1 causes the gas mixture to flow into the engine cylinder from the carburetor. Well, spark plug P
There is a problem in that sparks are generated at L, and the sparks ignite the mixed gas and start the engine.

That is, when the engine is started by the high voltage applied from the leak state detection device 1 and momentarily placed in the normal idle operating state, the engine cannot maintain cranking drive and the above-mentioned top dead state occurs. Since the cranking current signal for detecting the point signal is not output, the top dead center signal cannot be detected, and as a result, the high voltage generating circuit 1
It becomes impossible to operate as a leak state detection device. Therefore, using the leak state detection device 1 in this way, cranking the engine,
When the engine is started, either set the fuel cut valve installed in the carburetor of a typical vehicle to an inoperable state to prevent the mixed gas from flowing into the sill, or It is necessary to introduce an inert gas such as nitrogen gas from the air cleaner section of the engine to suppress ignition of the mixed gas flowing into the engine cylinder. Generally, the former method of setting the fuel cut valve in the carburetor section to an inoperable state is simple. Next, a leak state detecting device 1 based on a second embodiment of the present invention, which is an improvement of the leak state detecting device 1 based on the first embodiment and further improving the leak state detecting ability, is shown in FIGS. 7 and 8. This will be explained by.

The leak state detection device (2) according to the second embodiment is based on a method of detecting a voltage leak from a leak voltage waveform based on a voltage leak, and an attachment means PA is interposed between the plug cord PC and the ignition plug PL. Similar to the first embodiment, a pulsed high voltage is applied to the high voltage circuit section of the vehicle in synchronization with the compression top dead center during engine cranking, and based on the voltage leak of the pulsed high voltage waveform. , which is designed to clearly detect voltage leak phenomena from waveform changes. A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 shows a block diagram of the leak state detection device (2) based on this embodiment, and FIG. 8 shows a time chart of signal waveforms at various parts in FIG. As shown in FIG.
, a top dead center signal generation circuit 11, a high voltage generation circuit 1 that generates a pulsed high voltage, a detection circuit 3a1 determination circuit 4, and a display circuit 5. In the figure, the first
Portions having the same configuration, connections, and effects as those in the embodiment are given the same symbols, and explanations thereof will be omitted. The biopsy circuit 3a is
A voltage dividing circuit consisting of resistors 300 and 301 similar to the first embodiment, a Schmitt circuit consisting of resistors 322, 323, a diode 324 and an operational amplifier 325, a counter 326 having a pulse counting function, and resistors 327, 32.
8, 329, 330 and an adder circuit consisting of an operational amplifier 331, a switch element 332 such as an FET, and a resistor 333.
, a capacitor 334, and a sampling hold circuit consisting of an operational amplifier 335. In this embodiment, the high voltage output of the high voltage generating circuit 1 is electrically connected to one end of a coil cord CC of a high voltage circuit section of the vehicle via a high voltage cable 2 (not shown), and further leakage is prevented. The ground of the condition detection device ■ is connected to the engine body ground.

Although not shown, the connection point between the plug cord PC and the spark plug PL in the high voltage circuit section of the vehicle is electrically insulated by an attachment means PA made of an insulating material. The action will be explained below. With the above configuration and connection relationship, when the engine is cranked,
By the top dead center sensor 10, the battery BA and the starter S
A cranking current signal (FIG. 8a) during engine cranking drive that flows between T is detected and input to the top dead center signal generation circuit 11.

The top dead center signal generation circuit 11 generates a top dead center signal (FIG. 8g) and a pulse signal (FIG. 8C) in exactly the same manner as in the first embodiment.
, d), the former is input to the high voltage generation circuit 1, and the latter is input to the detection circuit 3a. (Since the top dead center sensor 10 and the top dead center signal generation circuit 11 are exactly the same as those in FIG. 5, the signal waveforms of each part are also given the same symbols as in the time chart in FIG. 6.) High voltage generation The circuit 1 generates a high voltage pulse (h in FIG. 8) in synchronization with the rising edge of the top dead center signal g, and the high voltage is transmitted to the high voltage circuit section of the vehicle via the high voltage cable 2. At the same time, the signal is applied to the input terminal of the detection circuit 3a. The output of the high voltage generation circuit 1 is input to the input resistor 300 of the voltage dividing circuit, and the output of the cranking current signal a is input to the reset terminal of the counter 326. A pulse signal C of a certain time duration, which is generated in synchronization with the positive direction rising timing, is inputted, and furthermore, one end of the switch element 332 of the sampling/holding circuit section is supplied with a pulse signal C in the top dead center signal generation circuit 11. , a pulse signal d having a constant time width, which is generated in synchronization with the rising timing of the cranking current signal a in the negative direction, is input. Under the above conditions, the pulsed high voltage generated from the high voltage generation circuit 1 has an oscillating damping waveform (h-A in Figure 8), and there is a voltage leak in the high voltage circuit of the vehicle under test. If it does not occur, the high voltage having the vibration-damped waveform is input as is to the detection circuit 3a, and a pulse signal corresponding to the frequency of the vibration-damped waveform is generated by the operation of the Schmitt circuit section in the detection circuit 3a. (FIG. 8 1), the number is counted by the counter 326, and the counter 32
The number of pulses of 6 outputs is converted into, for example, 1V pulses by an adder circuit and added. The counter 326
is reset by a pulse signal c periodically outputted from the top dead center signal generation circuit 11 in synchronization with the cranking current signal a, and at this time, the contents of the counter 326 are periodically Generally, a step voltage signal (eighth
(m) in FIG. 3 and input to the next stage sampling and holding circuit. Therefore, if the number of vibration damping waveforms when there is no voltage leak in the high voltage signal h is 4 to 5, the step voltage output m of the adder circuit is output as 4 to 5V, but the high voltage signal When a voltage leak occurs, the vibration waveform of the high voltage becomes a discharge waveform as shown in FIG. Therefore, this leakage voltage waveform is detected by the detection circuit 3a.
, the counter 326 counts only one pulse, and the step voltage m output from the adding path becomes 1V. Since the adder circuit output m is in the form of a signal that is periodically reset to 0, it cannot be used in the next sampling stage.
The hold circuit section converts the signal into a DC signal (m in FIG. 8) and inputs it to the next stage determination circuit 4. The determination circuit 4 determines the voltage value of the DC signal m output from the detection circuit 3a,
1 of the counting result of the counter 326 in the detection circuit 3a section
Judgment is made based on the judgment level corresponding to the pulse, and anything below the judgment level is judged as a voltage leak, and the judgment signal (Fig. 8k) is outputted and input to the next stage display circuit 5 to be displayed as a voltage leak. vinegar. Ru. FIG. 9 shows an example of the high voltage signal h when a voltage leak occurs when the pulsed high voltage output from the leak state detection device (2) of the present invention is applied to the high voltage circuit section of the vehicle. show.

FIG. 9A shows a high voltage signal waveform output from the high voltage generating circuit 1, which is an oscillation damping waveform having a maximum value of about 44 KV, and is a case where there is no voltage leak in the high voltage circuit section. .

Figure 9B shows approximately 6Tr1:F from a part of the high voltage circuit section.
This is a high voltage signal waveform when a voltage leak occurs to the engine, body, and ground through an air gap of n, and the leak voltage value is approximately 18 KV. Similarly, Fig. 9C shows approximately 1
This is a case where voltage leakage occurs through an air gap of 1Tr0n, and the leakage voltage is approximately 30KV. As is clear from the above examples of actual voltage leak phenomena, it is possible to easily detect the voltage leak state from the leak voltage waveform based on the voltage leak phenomenon by using the leak state detection device (■) of the present invention. That is clear. In each of the above embodiments, the present invention is applied to voltage leak detection in a high voltage circuit section of an ignition system of an engine installed in an automobile1, but the scope of application of the present invention is limited to this. It is clear that the present invention can be similarly applied to the ignition system of a general internal combustion engine.

Further, the detection circuit 3 of this embodiment detects a leak voltage signal as a leak signal based on a leak phenomenon, but the leak signal can be similarly applied even if a signal waveform change is detected.

As explained above, according to the present invention, the leak state can be quantitatively measured without relying on the operator's sensory test, and a high pulsed voltage synchronized with compression top dead center is externally applied. Therefore, even if the primary system of the ignition system is malfunctioning, it is possible to reliably determine the presence or absence of a leak condition, and it has the excellent effect of widening the judgment range for leak conditions compared to atmospheric pressure. can get.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the main parts where the high voltage generated from the ignition coil causes voltage leaks in the high voltage circuit of an engine using the high voltage ignition method. FIG. 3 is a sectional view showing the configuration of a high voltage cord constituting a circuit section. A pinhole is created in a part of the high voltage cord, and a point at a distance D from the outer diameter of the high voltage cord is connected to the conductor of the high voltage cord. FIG. 4 is a diagram showing the relationship between the interval length D and the leakage voltage when a high voltage is applied between them and a voltage leak occurs. FIG. 5, a circuit diagram showing the connection relationship between the block diagram of the device and the high voltage circuit section of the ignition circuit, shows a preferred embodiment based on the block diagram of the leak state detection device shown in FIG. 4. An electric circuit diagram, FIG. 6 is a time chart showing signal waveforms of each part of the leak state detection device shown in FIGS. 4 and 5, and FIG. 7 is a leak state detection device based on the second embodiment of the present invention. 8 is a time chart showing waveforms of various parts of the voltage soak detection device shown in FIG. 7, and FIG. 9 is an electric circuit diagram including a partial block diagram of the voltage soak detection device shown in FIG. 7. Figure 9A is a diagram showing an example of a high voltage signal when a voltage leak occurs when a pulsed high voltage output from the vehicle is applied to a high voltage circuit section of a vehicle. , FIG. 9B shows that when a voltage leak occurs through an air gap of about 6wun, FIG. 9C shows that the voltage leakage is about 11w.
The figures show cases in which voltage leak occurs through an air gap of n. IG...Ignition coil, CC...Coil code, DB
...Distributor, PC...Plug cord, PL...Spark plug, BA...Battery). ．． I, ■... Leak state detection device, 1... High voltage generation circuit, 2... High voltage cable, 3, 3a... Detection circuit, 4... Judgment circuit,
5... Display circuit, 6... Earth, 10... Top dead center sensor, 11... Top dead center signal generation circuit.

Claims (1)

[Claims] 1. A high-voltage cord consisting of a coil cord connected to an ignition coil of an internal combustion engine ignition system and a plurality of plug cords each connected to an ignition plug, the cord being disposed between the coil cord and the plug cord. When the high voltage circuit section equipped with a distributor is installed in the internal combustion engine, the secondary terminal of the ignition coil and the coil cord are electrically insulated, and the engine is cranked. By applying a high voltage synchronized with compression top dead center to the coil cord from the outside, a high voltage is distributed and applied to the high voltage circuit section, and a leak phenomenon occurs in the high voltage circuit section when high voltage is applied. A method for detecting a leak state in a high voltage circuit section of an ignition system of an internal combustion engine, characterized in that a leak signal based on the leak signal is detected. 2 A high voltage cord consisting of a coil cord connected to the ignition coil of an internal combustion engine ignition system and a plurality of plug cords each connected to a spark plug, and a high voltage cord comprising a distributor disposed between the coil cord and the plug cord. Means for electrically insulating between the secondary side terminal of the ignition coil of the voltage circuit section and the coil cord, a top dead center sensor that detects the compression top dead center position of the engine, and a signal output from the top dead center sensor. Based on the above, a signal generating circuit generates a top dead center signal synchronized with the compression top dead center position and two sets of pulse signals synchronized before and after the top dead center signal, and a pulse signal synchronized with the top dead center signal. a high-voltage power supply that generates a high voltage; a high-voltage cable that conductively connects the output of the high-voltage power supply to the high-voltage cord; and an output of the high-voltage power supply in response to two sets of pulse signals: It consists of a detection circuit that detects the maximum value, a judgment circuit that compares and judges the output signal level of the detection circuit with an arbitrarily settable judgment level, and a display circuit that displays the judgment result of the judgment circuit output. In the ranking driven state,
A leak state detection device in a high voltage circuit section of an internal combustion engine ignition system, characterized in that the leak state is detected when high voltage is distributed and applied.