JP2015132170A - Ignition device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a problem found in an internal combustion engine that a spark discharge generated between electrodes of a spark plug is blown off at a half period of discharge of an ignition coil to induce multiple discharge where discharge energy is decreased due to tumble and a spark discharge is generated again and the multiple discharge wears the electrodes of the spark plug.SOLUTION: A low voltage side 14a of a secondary coil 14 is connected to the ground through a secondary current detecting means 60, a switching means 50a is connected in parallel with a primary coil 12 and the switching means 50a is changed over between ON and OFF in response to a secondary current value detected by the secondary current detecting means 60. In addition, when the secondary current detecting means 60 detects a secondary current flowing in the secondary coil 14 and subsequently when its detected value is lower than a threshold, turns ON a switching signal to the switching means 50a, resulting in that the primary coil 12 and the switching means 50a become a closed loop, a current I is generated at the primary coil 12 to cause the secondary current flowed in the secondary coil 14 to be prevented from being flowed and then the spark discharge generated at the spark plug 30 is shut off.

Description

  The present invention relates to an ignition device for an internal combustion engine that generates a spark discharge by applying a power supply voltage boosted by an ignition coil to an ignition plug.

  Conventionally, in order to solve environmental problems and fossil fuel depletion problems, internal combustion engines use lean combustion with lean fuel with a high air-fuel ratio of the air-fuel mixture in the cylinder and supply exhaust gas after combustion again into the cylinder. (Exhaust gas recirculation) Combustion with a large amount. However, in such lean combustion, it is necessary to improve the ignitability by the spark plug by diffusing lean fuel in the cylinder, and turbulence (tumble) is generated in the air supplied into the cylinder. It is known that, in the latter half of the discharge of the ignition coil in which the discharge energy is reduced by this turbulent flow, the spark discharge generated between the electrodes of the spark plug is blown off, and multiple discharge is caused such that a spark discharge is generated again.

  In such multiple discharge, when the discharge energy remaining in the ignition coil is discharged again, the atoms collide with the electrode of the spark plug, causing sputtering and wearing out the electrode. In order to solve this problem, there is an ignition device that sets the duration of the spark discharge generated in the spark plug and forcibly cuts off the spark discharge when the spark current duration elapses and suppresses the consumption of the spark plug electrode. For example, Japanese Patent Laid-Open No. 2001-140739 (hereinafter “Patent Document 1”) has been proposed.

  In Patent Document 1, a primary winding, a secondary winding, and a coil core are provided, and the secondary winding is connected to an ignition coil that forms a closed loop together with an ignition plug mounted on an internal combustion engine, and one end of the primary winding. And a first switching means for energizing the primary winding for a certain period of time in synchronism with the rotation of the internal combustion engine and cutting off the energization current, and energizing the primary winding by the first switching means. An ignition device for an internal combustion engine that generates a high voltage for ignition in the secondary winding by cutting off and spark discharges the spark plug, wherein the spark discharge duration is based on the operating state of the internal combustion engine A spark discharge duration calculating means for calculating the primary winding short-circuit means built in the ignition coil and short-circuiting both ends of the primary winding of the ignition coil based on an external command, and the spark discharge duration Time A spark that forcibly cuts off the spark discharge of the spark plug by operating the primary winding short-circuit means to short-circuit both ends of the primary winding according to the spark discharge duration calculated by the calculation means. An internal combustion engine ignition device characterized by comprising: a discharge blocking means.

  Japanese Laid-Open Patent Publication No. 2001-193622 (hereinafter “Patent Document 2”) has also been proposed. In Patent Document 2, an ignition coil in which a secondary winding forms a closed loop together with an ignition plug attached to an internal combustion engine; Spark discharge generating means for generating a high voltage for ignition in the secondary winding and generating a spark discharge between the electrodes of the spark plug by energizing and interrupting a primary current flowing in the primary winding of the ignition coil; Based on the operating state of the internal combustion engine, the spark discharge duration calculating means for calculating the spark discharge duration required for burning the air-fuel mixture by the spark discharge of the spark plug, and the spark discharge duration calculating means The spark discharge blocking means for forcibly blocking the spark discharge of the spark plug according to the spark discharge duration, and the spark discharge from the occurrence of the spark discharge by the spark discharge generation means. A spark discharge cutoff timing control means for operating the spark discharge cutoff means for operating the spark discharge cutoff means at a time when the duration has elapsed, and the spark discharge cutoff means at the timing when the spark discharge duration has elapsed. There is described an internal combustion engine ignition device configured to be able to resume energization to the primary winding of an ignition coil.

JP 2001-140739 A JP 2001-193622 A

  However, the conventional ignition device for an internal combustion engine has the following problems. That is, the ignition device of Patent Document 1 uses primary winding short-circuiting means built in the ignition coil according to the spark discharge duration calculated by the spark discharge duration calculation means based on the operating state of the internal combustion engine. Therefore, the configuration in which the spark discharge is forcibly interrupted effectively suppresses the excessive supply of the discharge energy supplied to the spark plug, and the forcible shut-off of the spark discharge is surely performed. Although the consumption of the electrodes is suppressed, the value of the discharge current flowing between the electrodes of the spark plug is not limited to the operating state of the internal combustion engine, but depends on the temperature (coil resistance, plug resistance), plug gap, and in-cylinder flow velocity. Therefore, even if the spark discharge is forcibly cut off from the spark discharge duration, the discharge current value is too low and re-discharge occurs, or the spark discharge is forcibly cut off even though the discharge current value is high And cause problems.

  Further, the ignition device of Patent Document 2 has the same problem although the spark discharge interruption means is different from that of Patent Document 1, and the spark discharge interruption means is moved to the primary winding of the ignition coil at the timing when the spark discharge duration has elapsed. However, the discharge current value flowing between the electrodes of the spark plug is not limited to the operating state of the internal combustion engine, but the temperature (coil resistance, plug resistance), Since it varies depending on the plug gap and the in-cylinder flow velocity, the spark discharge cannot be reliably interrupted.

  Explaining such a variation in the discharge current value, as shown in FIG. 5, when the temperature in the cylinder or the spark plug is high, the resistance value between the electrodes is increased, and therefore the discharge current value is lowered. A factor that increases the temperature in the cylinder is that the amount of EGR is large. Moreover, even if the gap between the electrodes of the spark plug is wide or the pressure in the cylinder is high, the discharge current value becomes low. Furthermore, the discharge current value also decreases when the turbulent flow in the cylinder becomes stronger (faster).

  Explaining the problems of the above-mentioned Patent Documents 1 and 2 from FIG. 5, the spark discharge is cut off at point A when the discharge current value at the time when the spark discharge duration t has elapsed is in the cylinder or the temperature of the spark plug is low. When the temperature in the cylinder or the spark plug is high, the spark discharge is cut off at point B. In other words, if the discharge current value at the time of interruption is different, if the discharge current value is interrupted at point A where the discharge current value is high, the spark discharge may be forcibly interrupted despite the high discharge current value at which multiple discharge does not occur. If the discharge current value is cut off at point B, re-discharge occurs before the spark discharge duration t elapses. Therefore, it is difficult to provide an ignition device that prevents multiple discharges taking into account fluctuations in these discharge current values from the spark discharge duration t.

  The present invention has been made in view of the above problems, and is an ignition device for preventing a spark discharge generated between electrodes of a spark plug from blowing out and causing a multiple discharge in which a spark discharge occurs again. The discharge current value, which fluctuates depending on the temperature, plug gap, and cylinder flow velocity, is too low, causing blowout before forcibly shutting off the spark discharge, or spark discharge despite the high discharge current value. It is an object to provide an ignition device for an internal combustion engine that prevents forced shut-off.

  In order to solve the above problems, the present invention has the following configuration. That is, the invention of claim 1 energizes and interrupts the primary current flowing from the primary coil and the secondary coil, the ignition plug attached to each cylinder of the internal combustion engine, and the primary coil from the power supply device. An internal combustion engine comprising: a spark discharge control for generating a secondary current in the secondary coil to spark discharge the spark plug; and a spark discharge cutoff control for forcibly shutting off the spark discharge of the spark plug. In the ignition device for an engine, the spark discharge cutoff control is operated when the secondary current generated in the secondary coil is equal to or less than a desired value.

  In the invention according to claim 1, the spark discharge cutoff control may include a secondary current detecting means for detecting a secondary current on a low voltage side or a high voltage side of the secondary coil.

  According to a third aspect of the present invention, an ignition coil including a primary coil and a secondary coil, an ignition plug attached to each cylinder of an internal combustion engine, and a primary current flowing from the power supply device to the primary coil are turned on and off. An internal combustion engine comprising: a spark discharge control for generating a secondary current in the secondary coil to spark discharge the spark plug; and a spark discharge cutoff control for forcibly shutting off the spark discharge of the spark plug. In the engine ignition device, the spark discharge cutoff control is operated when noise is superimposed on a primary counter pressure generated in the primary coil.

  According to a fourth aspect of the present invention, an ignition coil including a primary coil and a secondary coil, an ignition plug attached to each cylinder of an internal combustion engine, and a primary current flowing from the power supply device to the primary coil are turned on and off. An internal combustion engine comprising: a spark discharge control for generating a secondary current in the secondary coil to spark discharge the spark plug; and a spark discharge cutoff control for forcibly shutting off the spark discharge of the spark plug. In the ignition device for an engine, the spark discharge cutoff control is operated when noise is superimposed on a secondary voltage generated in the secondary coil.

  In the first to fourth aspects of the invention, the primary coil connects switching means in parallel, and the spark discharge cut-off control drives the switching means to short-circuit the primary coil. It is good also as a structure which interrupts | blocks the spark discharge of an ignition plug compulsorily. Further, the secondary coil may be configured such that the switching means is connected to the low voltage side, and the spark discharge cutoff control forcibly cuts off the spark discharge of the spark plug by opening the switching means. Furthermore, the spark discharge cut-off control may be configured to forcibly cut off the spark discharge by passing a primary current flowing through the primary coil.

  With the above configuration, the invention according to claim 1 is an ignition device for an internal combustion engine that forcibly cuts off the spark discharge of the spark plug, and in the spark discharge cut-off control, the secondary current generated in the secondary coil has a desired value. By operating at the following, not only the operating state of the internal combustion engine but also the discharge current value that fluctuates depending on the temperature, plug gap, and cylinder flow velocity is too low and blows out before forcibly shutting off the spark discharge. Or an ignition device for an internal combustion engine that prevents the spark discharge from being forcibly cut off despite the high discharge current value.

  According to a third aspect of the present invention, in the ignition device for an internal combustion engine that forcibly cuts off the spark discharge of the spark plug, the spark discharge cut-off control operates when noise is superimposed on the primary back pressure generated in the primary coil. By doing so, not only the operating state of the internal combustion engine but also the discharge current value that fluctuates depending on the temperature, the plug gap, and the flow velocity in the cylinder is too low, and blowout occurs before forcibly shutting off the spark discharge, It is possible to prevent the problem that the spark discharge is forcibly cut off despite the high discharge current value. Furthermore, in the ignition device for an internal combustion engine that forcibly cuts off the spark discharge of the spark plug, the spark discharge cut-off control may be operated by noise superimposed on the secondary voltage generated in the secondary coil. Similar effects can be obtained.

1 is a block diagram of an ignition device for an internal combustion engine according to a first embodiment of the present invention. It is a figure which shows the time chart of the ignition signal of the ignition device made into Example 1, a primary current, a secondary current, and a switching signal. 3 is a flowchart illustrating operation control of the ignition device according to the first embodiment. It is a figure which shows the turbulent flow (tumble) in a cylinder in the combustion stroke of the internal combustion engine made into Example 1. FIG. It is a figure which shows the time chart of the ignition signal, primary current, and secondary current of an ignition device when the turbulent flow in the cylinder of an internal combustion engine is strong. It is a figure which shows the time chart of the ignition signal, primary current, secondary current, primary reverse pressure, and secondary voltage of the ignition device when blow-off occurs in the internal combustion engine. The block diagram of the ignition device for internal combustion engines which is the 2nd Example of this invention is shown. It is a figure which shows the time chart of the ignition signal of the ignition device made into Example 2, primary current, primary back pressure, and a switching signal. 6 is a flowchart illustrating operation control of an ignition device according to a second embodiment. The block diagram of the ignition device for internal combustion engines which is the 3rd Example of this invention is shown. It is a figure which shows the time chart of the ignition signal of the ignition device made into Example 3, a primary current, a secondary voltage, and a switching signal. 6 is a flowchart illustrating operation control of an ignition device according to a third embodiment.

  An example showing the embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram of an ignition device for an internal combustion engine according to a first embodiment of the present invention, and FIG. 1 is a diagram showing a time chart of an ignition signal, a primary current, a secondary current, and a switching signal of the ignition device. Fig. 3 is a flowchart showing the operation control of the ignition device, Fig. 3 is a diagram showing turbulent flow (tumble) in the cylinder during the combustion stroke of the internal combustion engine, and Fig. 4 is a diagram when the turbulent flow in the cylinder of the internal combustion engine is strong. FIG. 5 shows a time chart of the ignition signal of the ignition device, the primary current, and the secondary current. FIG. 5 shows the ignition signal of the ignition device when the blow-off occurs in the internal combustion engine, the primary current, the secondary current, FIGS. 6A and 6B show time charts of the primary reverse pressure and the secondary voltage, respectively.

  In FIG. 1A, an ignition device 100 includes an ignition coil 10, a power supply device 20, a spark plug 30, and an igniter 40. The output of the power supply device 20 is boosted and supplied to the ignition plug 30, which will be described later. The air-fuel mixture in the cylinder 210 of the internal combustion engine 200 is sparked. The ignition coil 10 includes a primary coil 12 made of a primary winding, a secondary coil 14 made of a secondary winding, and an iron core 16 made of a silicon steel plate. Further, the igniter 40 is composed of an IGBT (insulated gate bipolar transistor) and is driven by an ignition signal from an ECU (engine control unit) (not shown).

  Further, the low voltage side of the primary coil 12 is connected to the power supply device 20, and the high voltage side is connected to the collector side of the igniter 40. Further, the gate side of the igniter 40 is connected to the ECU, and the emitter side is connected to the ground.

  The low voltage side 14a of the secondary coil 14 is connected to a secondary current detection means 60 for detecting a secondary current flowing through the secondary coil 14. Further, the high voltage side 14 b of the secondary coil 14 is connected to the spark plug 30.

  The low-voltage side 14a of the secondary coil 14 is connected to the ground via a resistor 70a and a resistor 70b, and the connection point of the resistor 70a and the resistor 70b is connected to the inverting input terminal of the operational amplifier 72. Further, the non-inverting input terminal of the operational amplifier 72 is connected to the variable voltage power supply 74, and the output terminal is connected to one input side of the NOR gate 80.

  The connection point between the ECU and the gate side of the igniter 40 is connected to the other input side of the NOR gate 80 via a resistor 70c, and the connection point between the resistor 70c and the NOR gate 80 is connected to the capacitor 82. Is connected to the ground. Furthermore, switching means 50a is connected in parallel to the primary coil 12, and the switching means 50a is connected to the output side of the NOR gate 80.

  The NOR gate 80 closes the switching means 50a as shown in FIG. 1B when the inputs of both the ECU and the secondary current detecting means 60 are Low. That is, when the ignition signal from the ECU to the igniter 40 is turned off and the secondary current flowing through the secondary coil 14 detected by the secondary current detecting means 60 falls below a threshold value, the switching means 50a is closed. It is done.

  In FIG. 2, the ignition signal is a signal supplied from the ECU to the igniter 40. When the ignition signal is turned on, a gate current flows and a collector current is generated from the power supply device 20 through the primary coil 12. A primary current is stored in the primary coil 12 by this collector current. Further, the primary current stored in the primary coil 12 gradually increases. Further, when the ignition signal is turned off, the gate current is cut off, and the collector current from the power supply device 20 disappears. As a result, the primary current stored in the primary coil 12 also disappears.

  Further, when the primary current flowing through the primary coil 12 is interrupted, the secondary current flows through the secondary coil 14 disposed in an electromagnetically coupled manner by a counter electromotive force that cancels the change in the primary current. Further, the secondary current flowing through the secondary coil 14 is converged by spark discharge from the spark plug 30.

  The secondary current detection means 60 is set with a threshold value for the secondary current flowing through the secondary coil 14, and the secondary current threshold value set in the secondary current detection means 60 is 30 mA. Yes. Further, when the secondary current detecting means 60 detects the secondary current flowing through the secondary coil 14 and then falls below the threshold value, the output to the NOR gate 80 becomes Low.

  Further, when the ignition signal from the ECU to the igniter 40 is turned OFF, the output to the NOR gate 80 becomes Low, and when both the inputs of the NOR gate 80 become Low, the output to the switching means 50a is High, The switching means 50a is turned on. Thus, when the switching means 50a is turned on, the primary coil 12 and the switching means 50a become a closed loop as shown in FIG. 1B, and the current I is generated in the primary coil 12. The secondary current flowing through the secondary coil 14 is cut off, and the spark discharge generated in the spark plug 30 is cut off.

  In FIG. 3, the operation control of the ignition device 100 will be described. A determination is made as to whether or not spark discharge control in which a secondary current flows through the secondary coil 14 and spark discharge is generated from the spark plug 30 is started (S1). The secondary current detection means 60 detects the secondary current flowing through the secondary coil 14 (S2). The secondary current detection means 60 determines whether the secondary current flowing through the secondary coil 14 is below a set threshold value (S3), and the secondary current detection means 60 is determined at (S3). When the secondary current flowing through the secondary coil 14 falls below a threshold value, the switching signal for the switching means 50a is turned on, and spark discharge cutoff control is performed so that the primary coil 12 and the switching means 50a are closed loop (S4). ).

  In FIG. 4, a phenomenon in which the spark plug 30 is blown off by the turbulent flow generated in the internal combustion engine 200 will be described. In the intake stroke of the internal combustion engine 200, the intake valve 242 is pushed down by the intake cam 244, and the piston 220 is lowered toward the intake bottom dead center, whereby the outside air is introduced from the intake port 240, and the momentum of the outside air at the time of introduction is turbulent It becomes. Further, in the compression stroke of the internal combustion engine 200, the intake valve 242 and the exhaust valve 252 are both closed, and the piston 220 is raised toward the compression top dead center, whereby the inside of the cylinder 210 is increased to a specified compression ratio. . During this compression stroke, turbulent flow of the outside air introduced by the intake stroke occurs. When fuel is injected by the injector 260 during the compression stroke, the injected fuel is mixed with the outside air by this turbulent flow. . Furthermore, spark discharge is started from the spark plug 30 immediately before the compression top dead center of the internal combustion engine 200, but a phenomenon occurs in which the spark discharge flowing between the electrodes of the spark plug 30 is blown out by the turbulent flow.

  In FIG. 5, the secondary current flowing through the secondary coil 14 fluctuates due to the influence of turbulence generated in the cylinder 210 of the internal combustion engine 200. A secondary current when the turbulent flow in the cylinder 210 is large is indicated by a solid line, and a secondary current when the turbulent flow in the cylinder 210 is small is indicated by a broken line. The cause of the large turbulent flow in the cylinder 210 is when the internal combustion engine 200 is rotating at a high speed or when the amount of EGR for supplying exhaust gas again into the cylinder 210 is large, and the spark discharge of the spark plug 30 is caused. The phenomenon that blows out easily occurs. Furthermore, the conditions under which the secondary current flowing through the secondary coil 14 fluctuates are that the temperature in the cylinder 210 or the spark plug 30 is high, the gap between the electrodes of the spark plug 30 is wide, The pressure in the cylinder 210 may be high.

  In FIG. 6, the secondary current, the primary reverse pressure, and the secondary voltage when the spark discharge of the spark plug 30 is blown out will be described. The secondary current flowing through the secondary coil 14 is interrupted when the spark ignition of the spark plug 30 is blown out, and each time the spark discharge of the spark plug 30 is re-discharged, the secondary current also flows again. . Further, the primary reverse pressure blows out in the spark discharge of the spark plug 30, and when it is discharged again, a projecting waveform such as noise is superimposed as when the spark discharge is started. Further, the secondary voltage is blown out in the spark discharge of the spark plug 30 as in the case of the primary reverse pressure, and when discharged again, a projecting waveform such as noise is superimposed as when the spark discharge is started. .

  With the above configuration, the low voltage side 14a of the secondary coil 14 is connected to the ground via the secondary current detecting means 60, and the switching means 50a is connected to the primary coil 12 in parallel. When the secondary current detection means 60 detects the secondary current flowing through the secondary coil 14 and subsequently falls below the threshold value, when the switching signal to the switching means 50a is turned ON, the primary coil 12 and the switching means 50a Becomes a closed loop, and the current I generated in the primary coil 12 prevents the secondary current flowing in the secondary coil 14 from flowing, and the spark discharge generated in the spark plug 30 is cut off. As a result, not only the operating state of the internal combustion engine 200 but also the discharge current value that fluctuates depending on the temperature, the plug gap, and the in-cylinder flow velocity is too low, and blowout occurs before the spark discharge is forcibly cut off. The problem that the spark discharge is forcibly cut off despite the high discharge current value can be prevented.

  As a modification of the first embodiment, the secondary current detection means 60 may be provided on the high-voltage side 14b of the secondary coil 14. However, when the secondary coil high voltage side 14b is provided, it is necessary to use the secondary current detection means 60 composed of a resistor (a shunt) having a high breakdown voltage. Further, the circuit configuration of the secondary current detecting means 60 may be changed to any configuration depending on the design circumstances, and the NOR gate 80 is used as means for switching between opening and closing of the switching means 50a. You may implement by a method. Furthermore, the switching means 50a connected in parallel to the primary coil 12 may use an arbitrary element such as a thyristor or a transistor depending on design circumstances.

  The threshold value for the secondary current flowing through the secondary coil 14 set in the secondary current detecting means 60 is the output required by the ignition device 100 and the spark plug 30 provided in the internal combustion engine 200. It may be changed to any value depending on the design circumstances such as the distance between the electrodes. Further, the secondary current detecting means 60 is provided in the secondary coil low voltage side 14a, and when it falls below the threshold value of the secondary current, the switching signal to the switching means 50a is turned OFF and the secondary current 14 flows to the secondary coil 14. A configuration may be adopted in which the secondary current is interrupted and the spark discharge generated in the spark plug 30 is interrupted.

  Further, the secondary current detecting means 60 turns on the ignition signal supplied to the igniter 40 for a short time when the threshold value of the secondary current falls below the threshold value of the collector current from the power supply device 20 via the primary coil 12. The secondary current flowing through the secondary coil 14 may be cut off. Further, the turbulent flow generated in the internal combustion engine 200 is generated even in a configuration other than the configuration described in FIG. 4, and the spark discharge generated in the spark plug 30 is blown out even in an internal combustion engine having another configuration. Needless to say, the effect of this embodiment can be obtained.

  FIG. 7 is a block diagram of an ignition device for an internal combustion engine according to a second embodiment of the present invention, and FIG. 7 is a diagram showing time charts of the ignition signal, primary current, primary back pressure, and switching signal of the ignition device. FIG. 8 is a flowchart showing the operation control of the ignition device, and FIG.

  In the second embodiment, since the configuration other than the configuration of the ignition device 100 is the same as that of the first embodiment, the description thereof is omitted.

  In FIG. 7A, the low voltage side of the primary coil 12 is connected to the power supply device 20, and the high voltage side is connected to the collector side of the igniter 40. The gate side of the igniter 40 is connected to the ECU, and the emitter side is connected to the ground. Further, a primary back pressure detecting means 62 is connected in parallel to the primary coil 12, and the primary back pressure detecting means 62 detects a primary voltage generated in the primary coil 12.

  The low voltage side 14a of the secondary coil 14 is connected to the ground via the switching means 50b. Further, the high voltage side 14 b of the secondary coil 14 is connected to the spark plug 30.

  In FIG. 8, the ignition signal is a signal supplied from the ECU to the igniter 40. When the ignition signal is turned on, a gate current flows, and a collector current is generated from the power supply device 20 through the primary coil 12. A primary current is stored in the primary coil 12 by this collector current. Further, the primary current stored in the primary coil 12 gradually increases. Further, when the ignition signal is turned off, the gate current is cut off, and the collector current from the power supply device 20 disappears. As a result, the primary current stored in the primary coil 12 also disappears.

  Further, a primary voltage is applied to the primary coil 12 during a period when the ignition signal is ON. Further, when the ignition signal is turned off, the primary current flowing through the primary coil 12 is cut off, and a primary counter pressure is generated in the primary coil 12 due to the influence of the counter electromotive force generated in the secondary coil 14. A noise waveform that rises when a discharge occurs in the spark plug 30 appears in the primary back pressure.

  Further, the noise waveform generated in the primary back pressure is different from that generated when the spark discharge from the spark plug 30 is started, and the primary back pressure shown in FIG. Blowout occurs, and it is superimposed when it is discharged again.

  The primary back pressure detecting means 62 turns on the switching signal for the switching means 50b, and the primary back pressure detecting means 62 detects the noise waveform that rises when the spark plug 30 is discharged. The switching signal to the means 50b is OFF. Further, when the switching means 50b is turned off, the secondary current flowing through the secondary coil 14 is cut off as shown in FIG. 7B, and the spark discharge generated in the spark plug 30 is cut off.

  The primary back pressure detecting means 62 turns on the switching signal to the switching means 50b at the timing when the ignition signal of the igniter 40 is turned on.

  In FIG. 9, the operation control of the ignition device 100 will be described. A determination is made as to whether or not the spark discharge control in which a secondary current flows through the secondary coil 14 and spark discharge is generated from the spark plug 30 is started (S1), and the spark discharge control is started in (S1). The secondary counter pressure detecting means 62 detects the primary counter pressure applied to the primary coil 12 (S2). The primary back pressure detecting means 62 determines whether to detect a noise waveform that rises when the spark plug 30 is discharged due to the primary back pressure applied to the primary coil 12 (S3). When the primary reverse pressure detecting means 62 detects a noise waveform that rises when the spark plug 30 is discharged due to the primary reverse pressure applied to the primary coil 12 in (S3), the switching signal for the switching means 50b is turned off. Then, the secondary current flowing through the secondary coil 14 is cut off, and the spark discharge generated in the spark plug 30 is cut off (S4).

  With the above configuration, the low voltage side 14a of the secondary coil 14 is connected to the ground via the switching means 50b, and the primary counter pressure detecting means 62 is connected in parallel to the primary coil 12, When the primary back pressure detecting means 62 detects a noise waveform that rises when the spark plug 30 is discharged due to the primary back pressure applied to the primary coil 12, the primary back pressure detecting means 62 turns off the switching signal for the switching means 50b, and the 2 The secondary current flowing through the secondary coil 14 is cut off, and the spark discharge generated in the spark plug 30 is cut off, so that it varies depending not only on the operating state of the internal combustion engine 200 but also on the temperature, plug gap, and in-cylinder flow velocity. This prevents the problem of blowout before the spark discharge is forcibly cut off due to the discharge current value being too low, or forcibly shutting off the spark discharge even though the discharge current value is high. You can.

  As a modification of the second embodiment, the switching means 50b connected to the secondary coil low voltage side 14a may use an arbitrary element such as a thyristor or an electromagnetic switch depending on design circumstances. The switching means 50b may be connected to the secondary coil high voltage side 14b. However, when the secondary coil high voltage side 14b is provided, it is necessary to use an element having a high withstand voltage. Further, the switching means 50b is connected in parallel with the primary coil 12, and detects the noise waveform that rises when a discharge occurs in the spark plug 30 due to the primary reverse pressure applied to the primary coil 12. The primary coil 12 and the switching means 50a may be in a closed loop by turning on the switching signal to the means 50b, and the spark discharge generated in the spark plug 30 may be cut off.

  Further, the primary back pressure detecting means 62 detects the noise waveform that rises when the spark is generated in the spark plug 30 due to the primary back pressure applied to the primary coil 12, and the ignition signal supplied to the igniter 40. May be turned on for a short time to generate a collector current from the power supply device 20 via the primary coil 12 and cut off the secondary current flowing through the secondary coil 14. Further, the primary back pressure detecting means 62 detects the noise waveform that rises when a discharge occurs in the spark plug 30 due to the primary back pressure applied to the primary coil 12 for the second time. Control for shutting off the spark discharge generated at 30 may be performed. Thus, even when the first noise waveform superimposed on the primary back pressure is generated when the spark discharge from the spark plug 30 shown in FIG. 8 is started, normal spark discharge is performed. Without being interrupted, the spark discharge generated between the electrodes of the spark plug 30 is blown out, and only the multiple discharge in which the spark discharge is generated again can be prevented.

  Further, the primary back pressure detecting means 62 has turned on the switching signal to the switching means 50b at the timing when the ignition signal of the igniter 40 is turned on. For example, after the discharge from the spark plug 30 is started, It may be arbitrarily changed depending on design circumstances, for example, the switching signal is turned ON after a desired time has elapsed.

  FIG. 10 is a block diagram of an ignition device for an internal combustion engine according to a third embodiment of the present invention, and FIG. 10 is a diagram showing a time chart of the ignition signal, primary current, secondary voltage, and switching signal of the ignition device. FIG. 12 is a flowchart showing the operation control of the ignition device.

  In the third embodiment, since the configuration other than the configuration of the ignition device 100 is the same as that of the first embodiment, the description thereof is omitted.

  10A, the low voltage side of the primary coil 12 is connected to the power supply device 20, and the high voltage side is connected to the collector side of the igniter 40. The gate side of the igniter 40 is connected to the ECU, and the emitter side is connected to the ground. Further, a secondary voltage detection means 64 is connected in parallel to the secondary coil 14, and the secondary voltage detection means 64 detects a secondary voltage generated in the secondary coil 14.

  The low voltage side 14a of the secondary coil 14 is connected to the ground via the switching means 50b. Further, the high voltage side 14 b of the secondary coil 14 is connected to the spark plug 30.

  In FIG. 11, the ignition signal is a signal supplied from the ECU to the igniter 40, and when the ignition signal is turned on, a gate current flows and a collector current is generated from the power supply device 20 through the primary coil 12. A primary current is stored in the primary coil 12 by this collector current. Further, the primary current stored in the primary coil 12 gradually increases. Further, when the ignition signal is turned off, the gate current is cut off, and the collector current from the power supply device 20 disappears. As a result, the primary current stored in the primary coil 12 also disappears.

  Further, a primary voltage is applied to the primary coil 12 during a period when the ignition signal is ON. Further, when the ignition signal is turned off, the primary current flowing through the primary coil 12 is cut off, and a secondary voltage is generated in the secondary coil 14 by electromagnetic induction of the primary coil 12. A noise waveform that rises when the spark plug 30 is discharged appears in the secondary voltage.

  In addition to the noise waveform generated in the secondary voltage when spark discharge from the spark plug 30 is started, the secondary voltage shown in FIG. Is also superimposed when it is discharged again.

  The secondary voltage detection means 64 turns on a switching signal for the switching means 50b. When the secondary voltage detection means 64 detects a noise waveform that rises when the spark plug 30 is discharged, the switching means 50b. The switching signal to is turned off. Further, when the switching means 50b is turned off, the secondary current flowing in the secondary coil 14 is cut off as shown in FIG. 10B, and the spark discharge generated in the spark plug 30 is cut off.

  The secondary current detection means 64 turns on the switching signal to the switching means 50b at the timing when the ignition signal of the igniter 40 is turned on.

  In FIG. 12, the operation control of the ignition device 100 will be described. A determination is made as to whether or not spark discharge control in which a secondary current flows through the secondary coil 14 and spark discharge is generated from the spark plug 30 is started (S1). The secondary voltage detecting means 64 detects the secondary voltage applied to the secondary coil 14 (S2). The secondary voltage detecting means 64 determines whether or not to detect a noise waveform that rises when the spark plug 30 is discharged to the secondary voltage applied to the secondary coil 14 (S3). When the voltage detection means 64 detects a noise waveform that rises when a discharge occurs in the spark plug 30 in the secondary voltage applied to the secondary coil 14 in (S3), the voltage detection means 64 turns off the switching signal for the switching means 50b. The secondary current flowing through the secondary coil 14 is cut off, and the spark discharge generated in the spark plug 30 is cut off (S4).

  With the above configuration, the low voltage side 14a of the secondary coil 14 is connected to the ground via the switching means 50b, and the secondary voltage detecting means 64 is connected in parallel to the secondary coil 14. When the secondary voltage detecting means 64 detects a noise waveform that rises when the spark plug 30 is discharged, the secondary voltage detecting means 64 turns off the switching signal to the switching means 50b, cuts off the secondary current flowing through the secondary coil 14, and By shutting off the spark discharge generated in the spark plug 30, the discharge current value that fluctuates not only in the operating state of the internal combustion engine 200 but also in the temperature, plug gap, and in-cylinder flow velocity is too low to force the spark discharge. It is possible to prevent problems such as blow-off before being interrupted or forcibly interrupting spark discharge despite a high discharge current value.

  As a modification of the third embodiment, the switching means 50b connected to the secondary coil low voltage side 14a may use an arbitrary element such as a thyristor or an electromagnetic switch depending on design circumstances. The switching means 50b may be connected to the secondary coil high voltage side 14b. However, when the secondary coil high voltage side 14b is provided, it is necessary to use an element having a high withstand voltage. Further, the switching means 50b is connected in parallel with the primary coil 12, and detects the noise waveform that rises when a discharge occurs in the spark plug 30 due to the primary reverse pressure applied to the primary coil 12. The primary coil 12 and the switching means 50a may be in a closed loop by turning on the switching signal to the means 50b, and the spark discharge generated in the spark plug 30 may be cut off.

  The switching means 50b is connected in parallel to the primary coil 12, and detects the noise waveform that rises when the spark plug 30 is discharged due to the primary reverse pressure applied to the primary coil 12. The ignition signal supplied to 40 may be turned on for a short time to generate a collector current from the power supply device 20 via the primary coil 12 and cut off the secondary current flowing through the secondary coil 14. Further, the secondary voltage detecting means 64 detects the noise waveform that rises when the secondary voltage applied to the secondary coil 14 rises when the spark plug 30 is discharged for the second time. You may perform control which interrupts the generated spark discharge. Thus, even when the first noise waveform superimposed on the secondary voltage is generated when the spark discharge from the spark plug 30 shown in FIG. 8 is started, normal spark discharge is cut off. Accordingly, the spark discharge generated between the electrodes of the spark plug 30 is blown out, and only the multiple discharge in which the spark discharge is generated again can be prevented.

  Further, the switching means 50b turns on the switching signal from the secondary voltage detection means 64 at the timing when the ignition signal of the igniter 40 is turned on. For example, the switching signal may be turned on after the elapse of time, and may be arbitrarily changed depending on design circumstances.

10: Ignition coil
12: Primary coil
14: Secondary coil
14a: Secondary coil low voltage side
14b: Secondary coil high voltage side
16: Iron core
20: Power supply
30: Spark plug
40: Igniter (transistor)
50a, 50b: Switching means
52: Diode
60: Secondary current detection means
62: Primary back pressure detection means
64: Secondary voltage detection means
70a, 70b, 70c: Resistance
72: Operational amplifier
74: Variable voltage power supply
80: NOR gate
82: Capacitor
100: Ignition device
200: Internal combustion engine
210: Cylinder
220: Piston
240: Inlet port
242: Intake valve
244: Intake cam
252: Exhaust valve
260: Injector

Claims (7)

An ignition coil comprising a primary coil and a secondary coil;
A spark plug attached to each cylinder of the internal combustion engine;
Spark discharge control in which a secondary current is generated in the secondary coil by energizing / cutting off a primary current flowing from the power supply device to the primary coil, and the spark plug is spark-discharged;
In an ignition device for an internal combustion engine, comprising: a spark discharge cutoff control for forcibly blocking a spark discharge of the spark plug;
The ignition device for an internal combustion engine, wherein the spark discharge cutoff control is operated when a secondary current generated in the secondary coil becomes a desired value or less.   2. The ignition device for an internal combustion engine according to claim 1, wherein the spark discharge cutoff control includes secondary current detection means for detecting a secondary current on a low voltage side or a high voltage side of the secondary coil. An ignition coil comprising a primary coil and a secondary coil;
A spark plug attached to each cylinder of the internal combustion engine;
Spark discharge control in which a secondary current is generated in the secondary coil by energizing / cutting off a primary current flowing from the power supply device to the primary coil, and the spark plug is spark-discharged;
In an ignition device for an internal combustion engine, comprising: a spark discharge cutoff control for forcibly blocking a spark discharge of the spark plug;
The ignition apparatus for an internal combustion engine, wherein the spark discharge cutoff control is operated when noise is superimposed on a primary counter pressure generated in the primary coil. An ignition coil comprising a primary coil and a secondary coil;
A spark plug attached to each cylinder of the internal combustion engine;
Spark discharge control in which a secondary current is generated in the secondary coil by energizing / cutting off a primary current flowing from the power supply device to the primary coil 12 to spark discharge the spark plug;
In an ignition device for an internal combustion engine, comprising: a spark discharge cutoff control for forcibly blocking a spark discharge of the spark plug;
The ignition apparatus for an internal combustion engine, wherein the spark discharge cutoff control is operated when noise is superimposed on a secondary voltage generated in the secondary coil. The primary coil connects switching means in parallel;
5. The spark discharge cut-off control forcibly cut off the spark discharge of the spark plug by driving the switching means to short-circuit the primary coil. An ignition device for an internal combustion engine according to the item. The secondary coil connects the switching means to the low voltage side,
5. The internal combustion engine according to claim 1, wherein the spark discharge cutoff control forcibly cuts off a spark discharge of the spark plug by opening the switching means. 6. Ignition device.   5. The internal combustion engine according to claim 1, wherein the spark discharge cutoff control applies a primary current flowing through the primary coil to forcibly cut off the spark discharge. 6. Ignition device.

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