JP2016114039A - Ignitor of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignitor of an internal combustion engine which performs re-ignition operation by using a single ignition coil when the misfire occurs, and can further surely avoid the misfire.SOLUTION: This ignitor of an internal combustion engine performs an ignition operation using a battery voltage VBAT as an application voltage VIN of a primary coil 2b of an ignition coil 2 as a basic ignition operation. When it is determined that a misfire occurs after the basic ignition operation, the ignitor switches the application voltage VIN of the primary coil 2b to a boosted voltage VBST generated by a boosting circuit 7, and performs an ignition operation using the boosted voltage VBST as the application voltage VIN of the primary coil 2b as a re-ignition operation (steps 11, 12 in Fig. 2).SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ignition device for an internal combustion engine that uses one ignition coil for one cylinder and performs an ignition operation in accordance with a misfire occurrence state.

  As a recent internal combustion engine, in order to improve fuel efficiency, fuel that directly injects fuel from a fuel injection valve into a combustion chamber and generates an extremely lean air-fuel mixture in the combustion chamber for combustion is known. . In addition, since an extremely lean air-fuel mixture is difficult to burn and easily misfires, in order to perform ignition reliably, for example, by providing two sets of ignition coils in one cylinder and driving them alternately, There is also known an ignition device that performs a plurality of ignition operations (multiple ignition) in a combustion cycle.

  However, in the above ignition device, it is necessary to install two sets of ignition coils in each cylinder, which hinders downsizing of the internal combustion engine. In addition, since multiple ignition is always performed regardless of the actual combustion state of the air-fuel mixture, multiple ignition may be performed even though there is actually no misfire or there is a risk of it. In this case, electric energy for ignition is wasted and there is a risk that deterioration due to overheating of the ignition coil may be accelerated.

  Moreover, what was disclosed by patent document 1, for example as another conventional ignition device is known. In this ignition device, the presence or absence of misfire is determined from the fluctuation state of the rotational angular velocity of the internal combustion engine, and when it is determined that misfire has occurred, the energization time of the primary coil of the ignition coil is extended in the next and subsequent combustion cycles. Thus, misfire is avoided by increasing the ignition energy.

Japanese Patent Laid-Open No. 10-47216

  As described above, in the conventional ignition device, when it is determined that there is a misfire, the energization time of the primary coil of the ignition coil is extended in order to increase the ignition energy. However, the period suitable for ignition in one combustion cycle is limited, and the period (time) becomes shorter particularly in the high rotation state of the internal combustion engine. On the other hand, when the energization time is simply extended as described above, the time required for the entire ignition operation becomes longer. Therefore, this ignition operation is re-ignited in the current combustion cycle determined to have misfire ( It is difficult to implement as multiple ignition). For this reason, in this conventional ignition device, it is assumed that the ignition operation accompanied by the extension of the energization time of the primary coil is executed in the next and subsequent combustion cycles, and the misfire is finally eliminated in the current combustion cycle. I can't.

  The present invention has been made to solve the above-described problems. When a misfire occurs, a reignition operation can be performed using one ignition coil, thereby preventing misfire more reliably. An object of the present invention is to provide an ignition device for an internal combustion engine.

  In order to achieve the above object, the invention according to claim 1 generates an induced electromotive force in the secondary coil 2c by applying and blocking a voltage to the primary coil 2b of the ignition coil 2, and An ignition device for an internal combustion engine that ignites an air-fuel mixture in a combustion chamber by an ignition operation for spark discharge, and applies voltage to a battery 6, a booster circuit 7 that boosts a voltage VBAT of the battery 6, and a primary coil 2b Alternatively, the first switching element (first transistor Q1 in the embodiment (hereinafter the same in this section)) for switching the cutoff and the boosted voltage obtained by boosting the voltage VIN applied to the primary coil 2b by the battery voltage VBAT or the booster circuit 7 By controlling the second switching element (second transistor Q2) for switching to the voltage VBST and the first and second switching elements. Control means (ECU4) for executing an ignition operation using the battery voltage VBAT as the applied voltage VIN of the primary coil 2b as a basic ignition operation, and a misfire determination means (ECU4, which determines whether misfire has occurred) Step 2) of FIG. 2 and the control means boosts the applied voltage VIN of the primary coil 2b after the basic ignition operation when it is determined that a misfire has occurred after the basic ignition operation. The ignition operation using the voltage VBST is executed as a reignition operation (steps 11 and 12 in FIG. 2).

  This ignition device for an internal combustion engine ignites an air-fuel mixture by an ignition operation in which an induced electromotive force is generated in a secondary coil by applying and shutting off a voltage to a primary coil of an ignition coil, and a spark is discharged by an ignition plug. The application or interruption of the voltage to the primary coil is switched by the first switching element. The ignition device includes a battery and a booster circuit that boosts the voltage of the battery, and the voltage applied to the primary coil is switched to the battery voltage or the boosted voltage by the booster circuit by the second switching element. By controlling the operations of the first and second switching elements by the control means, the basic ignition operation using the battery voltage as the applied voltage of the primary coil is executed.

  When it is determined that misfire has occurred after the basic ignition operation, a reignition operation using the boosted voltage as the applied voltage of the primary coil is executed after the basic ignition operation. In this way, when it is determined that a misfire has occurred, the ignition (magnetic) energy necessary for spark discharge of the spark plug is accumulated in a shorter time by switching the applied voltage of the primary coil to a higher boosted voltage. The time required for operation can be shortened. As a result, the reignition operation can be executed following the basic ignition operation using one ignition coil, and misfire can be avoided more reliably. In this case, the reignition operation may be executed subsequent to the misfire determination in the current combustion cycle, or may be executed in the subsequent combustion cycles. Especially in the former case, it is possible to effectively eliminate the misfire state generated in the current combustion cycle.

  Furthermore, in the present invention, since reignition operation is possible with one ignition coil, unlike a conventional device that performs multiple ignition using two sets of ignition coils, it can be arranged in a compact manner and downsizing an internal combustion engine. There is no hindrance. Also, since the basic ignition operation is normally executed and the reignition operation is executed only when it is determined that a misfire has occurred, it is less than the conventional case in which multiple ignition is always performed. Electric energy can efficiently avoid misfire and can suppress deterioration due to overheating of the ignition coil.

  The invention according to claim 2 is the ignition device for an internal combustion engine according to claim 1, wherein the internal combustion engine has a fuel injection valve 5 for injecting fuel into the combustion chamber by application of a voltage to the solenoid 5a, and the solenoid 5a. Further includes a third switching element and a fourth switching element (third transistor Q3, fourth transistor Q4) for switching the applied voltage to the battery voltage VBAT or the boosted voltage VBST, and the control means includes the first to fourth switching elements. By controlling the above, the ignition coil 2 and the fuel injection valve 5 are driven by applying the battery voltage VBAT or the boosted voltage VBST to the primary coil 2b and the solenoid 5a at different timings.

  According to this configuration, the fuel injection valve is of an electromagnetic type, and fuel is injected into the combustion chamber by applying a battery voltage or a boosted voltage to the solenoid. The applied voltage of the solenoid is switched to the battery voltage or the boosted voltage by the third and fourth switching elements. Then, by controlling the first to fourth switching elements by the control means, the ignition coil and the fuel injection valve are driven by applying the battery voltage or the boosted voltage to the primary coil and the solenoid at different timings.

  As described above, the ignition device and the fuel injection valve can be driven using the common drive circuit including the first to fourth switching elements and the common control means. When the fuel injection valve is of the type that injects fuel into the combustion chamber, the drive circuit has a booster circuit, and the fuel injection valve is driven while switching the voltage applied to the solenoid from the boosted voltage by the booster circuit to the battery voltage. Is relatively common. Therefore, for example, by simply incorporating the first and second switching elements into the existing drive circuit for such a fuel injection valve, the drive circuit of the present invention shared by the ignition device and the fuel injection valve can be easily realized. Is possible.

  According to a third aspect of the invention, there is provided an ignition device for an internal combustion engine according to the first or second aspect, wherein a secondary coil voltage detecting means (ECU4) for detecting a voltage generated in the secondary coil 2c as a secondary coil voltage VC2 is provided. Further, the misfire determination means determines that a misfire has occurred when the secondary coil voltage VC2 detected immediately after the basic ignition operation is smaller than a predetermined value (threshold value VREF) (step of FIG. 2). 2).

  When the air-fuel mixture is normally ignited and combusted by the ignition operation, an ionic current is generated by the combustion. Therefore, the secondary coil voltage increased by the ignition operation is gradually lowered thereafter. On the other hand, when a misfire occurs, no ionic current is generated, so the secondary coil voltage rapidly decreases after the ignition operation. Therefore, when the secondary coil voltage detected immediately after the basic ignition operation is smaller than the predetermined value, it can be appropriately determined that misfire has occurred. Further, according to this determination method, since the determination result can be obtained in a relatively short time after the basic ignition operation, the reignition operation is performed particularly when the reignition operation is performed following the misfire determination in the current combustion cycle. Can be performed with sufficient time.

  According to a fourth aspect of the present invention, there is provided an ignition device for an internal combustion engine according to any one of the first to third aspects, wherein the boosted voltage detecting means (ECU4) for detecting the boosted voltage VBST and the detected boosted voltage VBST are used. And an application time setting means (ECU 4, step 5 in FIG. 2, FIG. 3) for setting the application time TEA of the primary coil 2b for the reignition operation.

  As described above, the ignition energy accumulation rate when a voltage is applied to the primary coil changes according to the applied voltage. According to this configuration, since the application time of the primary coil for the reignition operation is set according to the detected actual boosted voltage, the primary coil is reapplied without excess and deficiency, and the necessary ignition energy is obtained. Can be obtained efficiently.

It is a figure which shows the ignition device of the internal combustion engine by embodiment of this invention with the drive device of a fuel injection valve. It is a flowchart which shows a multiple ignition control process. It is a map used by multiple ignition control processing. It is a timing chart which shows the operation example obtained by embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, an ignition device for an internal combustion engine to which the present invention is applied includes an ignition plug 1, an ignition coil 2 for generating spark discharge in the ignition plug 1, and a drive circuit 3 for driving the ignition coil 2. And an electronic control unit (hereinafter referred to as “ECU”) 4 for controlling the drive circuit 3.

  An internal combustion engine (not shown) has, for example, four cylinders, and each cylinder is provided with a spark plug 1 and an ignition coil 2, and a fuel injection valve 5 that directly injects fuel into a combustion chamber. . As shown in FIG. 1, the fuel injection valve 5 is connected to the drive circuit 3, and the operation of the fuel injection valve 5 is controlled by the ECU 4 via the drive circuit 3. That is, the drive circuit 3 and the ECU 4 are shared for driving and controlling the spark plug 1 and the fuel injection valve 5.

  The drive circuit 3 includes a booster circuit 7 for boosting the voltage VBAT of the battery 6, and first to fifth transistors Q1 to Q5 as switching elements for performing various switching operations described later.

  The ignition coil 2 includes an iron core 2a, a primary coil 2b and a secondary coil 2c wound around the iron core 2a. One end of the primary coil 2b is connected to the battery 6 via the diode D1, the solenoid S1, and the capacitor C1, and the other end is connected to the collector of the bipolar first transistor Q1. The emitter of the first transistor Q1 is connected to the ground, and the base is connected to the ECU 4. One end of the secondary coil 2c is connected to one of a pair of electrodes of the spark plug 1 facing the combustion chamber, and the other end of the secondary coil 2c and the other electrode of the spark plug 1 are connected to the ground.

  With the above configuration, when the switching signal (hereinafter referred to as “ignition signal”) SI is input from the ECU 4 to the base of the first transistor Q1, the first transistor Q1 is turned on, whereby the primary coil 2b of the ignition coil 2 is turned on. Battery voltage VBAT is applied, and primary coil 2b is energized. Thereafter, when the first transistor Q1 is turned off, the application (energization) of the primary coil 2b is interrupted, and a high-voltage induced electromotive force is generated at both ends of the secondary coil 2c. By performing a spark discharge between the electrodes, an ignition operation using the battery voltage VBAT as the applied voltage VIN of the primary coil 2b is performed.

  A resistor R1 is provided between the emitter of the first transistor Q1 and the ground, and the emitter-resistor R1 is connected to the ECU 4. Based on the output, the ECU 4 detects the voltage VC1 of the primary coil 2b. To do. Similarly, a resistor R2 is provided between the secondary coil 2c and the ground, and the secondary coil 2c and the resistor R2 are connected to the ECU 4. Based on the output, the ECU 4 determines the voltage of the secondary coil 2c ( VC2) (hereinafter referred to as “secondary coil voltage”) is detected.

  The booster circuit 7 includes two sets of solenoids L0, a field effect transistor Q0, a diode D0, and a capacitor C0. One end of each of the two solenoids L0 and L0 is connected in parallel to the output side of the battery 6, and the other end of each solenoid L0 is connected to the drain of the transistor Q0. The source of the transistor Q0 is connected to the ground, and the gate is connected to the ECU 4. Each diode D0 is connected between the solenoid L0 and the drain of the transistor Q0, and is connected to the input side of the capacitor C0.

  In the booster circuit 7 having the above configuration, when the switching signal SVI is input from the ECU 4 to the gate of each transistor Q0, the transistor Q0 is turned on, so that the battery voltage VBAT is applied to each solenoid L0 and electric energy is stored. . When the transistor Q0 is turned off from this state, the electric energy stored in the solenoid L0 is supplied to and stored in the capacitor C0 via the diode D0, thereby boosting the voltage. Further, the output side of the capacitor C0 is connected to the ECU 4, whereby the boosted voltage VBST, which is the output voltage of the booster circuit 7, is detected.

  The output side of the capacitor C0 of the booster circuit 7 is connected to the drain of the field effect type second transistor Q2. The source of the second transistor Q2 is connected to one end of the primary coil 2b of the ignition coil 2, and the gate is connected to the ECU 4. According to this configuration, when the switching signal SCI is input from the ECU 4 to the gate of the second transistor Q2, the second transistor Q2 is turned on, so that the boost voltage VBST is applied to the primary coil 2b of the ignition coil 2, Thereafter, the second transistor Q2 is turned off to perform an ignition operation using the boosted voltage VBST as the applied voltage VIN of the primary coil 2b.

  The output side of the capacitor C0 of the booster circuit 7 is further connected to the drain of the field effect type third transistor Q3. The source of the third transistor Q3 is connected to one end of the solenoid 5a of the fuel injection valve 5, and the gate is connected to the ECU 4. The other end of the solenoid 5a of the fuel injection valve 5 is connected to the collector of the bipolar fifth transistor Q5. The emitter of the fifth transistor Q1 is connected to the ground, and the base is connected to the ECU 4.

  The output side of the battery 6 is connected to the emitter of the bipolar fourth transistor Q4 between the diode D1 and the solenoid L0 of the booster circuit 7. The collector of the fourth transistor Q4 is connected to one end side of the solenoid 5a of the fuel injection valve 5 via the Zener diode D2, is further connected to the ground via the Zener diode D3, and the base is connected to the ECU 4. .

  With the above configuration, when the switching signal SCF is input from the ECU 4 to the gate of the third transistor Q3 with the second transistor Q2 on the ignition coil 2 side turned off, the third transistor Q3 is turned on. The boosted voltage VBST is applied from the booster circuit 7 to the solenoid 5a of the fuel injection valve 5. In this state, when the switching signal SF is input from the ECU 4 to the base of the fifth transistor Q5, a large drive current by the boosted voltage VBST is supplied to the solenoid 5a, whereby the fuel injection valve 5 is opened. Fuel is injected into the combustion chamber.

  Further, after this valve opening, the third transistor Q3 is turned off, and when the switching signal SBF is input from the ECU 4 to the base of the fourth transistor Q4, the fourth transistor Q4 is turned on, whereby the applied voltage of the solenoid 5a. Is switched to the battery voltage VBAT. As a result, a smaller drive current (holding current) based on the battery voltage VBAT is supplied to the solenoid 5a, whereby the fuel injection valve 5 is held open. Further, after that, the fourth and fifth transistors Q4 and Q5 are turned off, so that the fuel injection valve 5 is closed.

  As shown in FIG. 1, a CRK signal and a TDC signal, which are pulse signals, are input from the crank angle sensor 21 to the ECU 4. The CRK signal is input every predetermined crank angle (for example, 1 °). The ECU 4 calculates the rotational speed (hereinafter referred to as “engine speed”) NE of the internal combustion engine based on the CRK signal.

  The TDC signal is a signal indicating that the piston (not shown) of the internal combustion engine is in a predetermined crank angle position near the top dead center at the start of the intake stroke in any of the cylinders. In the case of a cylinder, it is output every 180 ° crank angle. The ECU 4 calculates, for each cylinder, a crank angle CA based on the TDC signal generation timing based on the TDC signal and the CRK signal.

  Further, the ECU 4 receives a detection signal indicating an operation amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) of the vehicle from the accelerator opening sensor 22, and various sensors (not shown). From this, a detection signal indicating the operating state of the internal combustion engine (for example, the cooling water temperature, the intake air amount, the EGR amount, etc.) is input.

  The ECU 4 is composed of a microcomputer having a CPU, a RAM, a ROM, an I / O interface (all not shown), and the like. The ECU 4 calculates the fuel injection amount by the fuel injection valve 5, the fuel injection timing, and the ignition timing by the ignition device in accordance with the sensor sensors 21, 22 and detection signals from the various sensors. And based on those calculation results, by controlling on / off of the switching signals to the first to fifth transistors Q1 to Q5 and the transistor Q0 of the booster circuit 7, the fuel injection operation of the fuel injection valve 5 and Controls the ignition operation of the ignition device. In the present embodiment, the ECU 4 corresponds to control means, misfire determination means, secondary coil voltage detection means, boost voltage detection means, and application time setting means.

  The fuel injection timing is set, for example, in the compression stroke, and the ignition timing is set, for example, in the expansion stroke after the fuel injection timing. From this relationship, the application of the fuel injection valve 5 and the application of the ignition coil 2 Blocking is performed at different timings. Therefore, by using the common drive circuit 3 and ECU 4 to sequentially drive the fuel injection valve 5 and the ignition coil 2 at different timings, the fuel injection and the ignition operation can be performed without any trouble.

  FIG. 2 shows a multiple ignition control process executed by the ECU 4. This multiple ignition control is synchronized with the input of the CRK signal immediately after executing a normal ignition operation using the battery voltage VBAT (hereinafter referred to as “basic ignition operation”), for example, during a predetermined period from the end of the expansion stroke. It is executed for each cylinder.

  In this process, first, in step 1 (illustrated as “S1”, the same applies hereinafter), it is determined whether or not the re-ignition operation mode flag F_IGR is “1”. If the answer is NO and not in the reignition operation mode, it is determined whether or not the secondary coil voltage VC2 detected by the ECU 4 is smaller than a predetermined threshold value VREF for misfire determination (step 2).

  This determination is based on the following characteristics of the secondary coil voltage VC2. That is, when the air-fuel mixture is normally ignited and combusted by the ignition operation, an ionic current is generated by the combustion. Therefore, as shown in FIG. 4D (crank angle CA: CAIGR and later), the ignition operation is performed. The secondary coil voltage VC2 that has been increased due to the above has gradually decreased to a value close to 0 after passing through a state of gradually decreasing. On the other hand, when a misfire occurs, no ionic current is generated. Therefore, as shown in FIG. 4D (CA: CA2 to CAIGR), the secondary coil voltage VC2 has a value near 0 after the ignition operation. Suddenly decreases.

  Based on the above characteristics, when the answer to step 2 is NO and the secondary coil voltage VC2 is equal to or higher than the threshold value VREF, it is determined that the air-fuel mixture burns normally by the basic ignition operation and no misfire has occurred, Assuming that the reignition operation is not executed, this processing is terminated as it is.

  On the other hand, if the answer to step 2 is YES and the secondary coil voltage VC2 is lower than the threshold value VREF, it is determined that a misfire has occurred, the process proceeds to the re-ignition operation mode after step 3, and a misfire state occurs. A re-ignition operation is performed to eliminate the problem.

  First, in step 3, the reignition operation mode flag F_IGR is set to “1” to indicate that the reignition operation mode is being performed. Further, by outputting the switching signal SCI to the second transistor Q2, the applied voltage VIN of the primary coil 2b of the ignition coil 2 is switched from the battery voltage VBAT during the basic ignition operation to the boost voltage VBST (step 4).

  Next, the reignition timing CAIGR is calculated on the basis of the crank angle CA according to the detected accelerator opening AP and engine speed NE (step 5). Next, the application time TEA of the primary coil 2b is calculated by searching the map shown in FIG. 3 according to the detected boosted voltage VBST (step 6). In this map, the higher the boosted voltage VBST, the higher the ignition energy accumulation rate due to the application of the voltage to the primary coil 2b, and the ignition energy required for spark discharge of the spark plug 1 can be obtained in a shorter time. The time TEA is set to a smaller value.

  Next, the calculated application time TEA is converted into the applied crank angle CAEA using the engine speed NE and the conversion coefficient KTC (step 7), and the applied crank angle CAEA is subtracted from the reignition timing CAIGR. Thus, the re-application start timing CAST is calculated (step 8), and this process is terminated.

  After shifting to the reignition operation mode as described above, the answer to step 1 becomes YES. In this case, in step 9, it is determined whether or not the crank angle CA is equal to the reignition timing CAIGR. If the answer is NO, it is determined whether or not the crank angle CA is equal to the re-application start timing CAST (step 10). When this answer is NO, this processing is ended as it is.

  On the other hand, when the answer to step 10 is YES and the crank angle CA reaches the re-application start timing CAST, the boost signal VBST is applied to the primary coil 2b by outputting the ignition signal SI to the first transistor Q1. Start (step 11) and end this process.

  Thereafter, when the answer to Step 9 is YES and the crank angle CA reaches the reignition timing CASRT, the ignition signal SI is turned off and the application of the primary coil 2b is interrupted to execute the reignition operation. (Step 12). Finally, the reignition operation mode flag F_IGR is reset to “0” (step 13), and this process is terminated.

  FIG. 4 shows an example of operation obtained by the embodiments described so far. In this example, a misfire occurs after the basic ignition operation, and the misfire state is eliminated by a re-ignition operation executed accordingly. In this example, first, when the crank angle CA = CA1, the ignition signal SI is output to start application of the battery voltage VBAT to the primary coil 2b, and then the application is cut off when CA = CA2. As a result, the basic ignition operation is executed.

  If a misfire occurs after this basic ignition operation, it is determined that a misfire has occurred because the secondary coil voltage VC2 falls below the threshold value VREF (step 2: FIG. 2, YES, CA = CA3). Accordingly, the reignition operation is executed. Specifically, the applied voltage VIN of the primary coil 2b is immediately switched from the battery voltage VBAT to the boosted voltage VBST (step 4), and the reignition timing CAIGR and the reapplication start timing CAST of the primary coil 2b are calculated. (Steps 5 and 8).

  When the crank angle CA reaches the re-application start timing CAST, the application of the primary coil 2b is started (step 11). In this case, since the higher boosted voltage VBST is used as the applied voltage VIN, the primary coil current IC1 increases faster than the case of the battery voltage VBAT, and the ignition energy required for spark discharge of the spark plug 1 is increased. Is obtained in a shorter time.

  Thereafter, when the crank angle CA reaches the reignition timing CAIGR, the reignition operation is performed by cutting off the application of the primary coil 2b, thereby eliminating the misfire state.

  As described above, according to the present embodiment, when it is determined that a misfire has occurred after the basic ignition operation, subsequently, the applied voltage VIN of the ignition coil 2 is switched from the battery voltage VBAT to the boost voltage VBST. Perform a re-ignition operation. As a result, the ignition energy required for spark discharge of the spark plug 1 is accumulated in a shorter time, so that the reignition operation can be executed with one ignition coil 2 in the current combustion cycle, and the misfire state can be eliminated. .

  Further, since reignition operation is possible with one ignition coil 2, unlike a conventional device that performs multiple ignition using two sets of ignition coils, it can be arranged compactly and hinders downsizing of an internal combustion engine. Absent. Furthermore, since the basic ignition operation is normally performed and the reignition operation is performed only when it is determined that a misfire has occurred, less electrical energy is required compared to the conventional case in which multiple ignition is always performed. Thus, misfire can be efficiently avoided and deterioration due to overheating of the ignition coil can be suppressed.

  In addition, the common drive circuit 3 including the first to fifth transistors Q1 to Q5 and the booster circuit 7 and the common ECU 4 can be used to drive the ignition coil 2 and the fuel injection valve 5. For example, for the fuel injection valve The drive circuit 3 can be easily realized simply by incorporating the first and second transistors Q1 and Q2 into the existing drive circuit.

  Furthermore, since misfire is determined based on the secondary coil voltage VC2 reflecting the ion current according to the combustion state immediately after the basic ignition operation, the misfire can be determined appropriately and quickly, and reignition following the misfire determination is performed. The operation can be performed with sufficient time. In addition, since the application time TEA of the primary coil 2b for the reignition operation is set according to the detected actual boosted voltage VBST, the reapplying of the primary coil 2b is performed without excess or deficiency and is necessary for the reignition operation. Ignition energy can be obtained efficiently.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, when it is determined that misfire has occurred after the basic ignition operation, the re-ignition operation is subsequently executed in the current combustion cycle. The present invention is not limited to this, and if it is determined that misfiring has occurred, it is assumed that misfiring is likely to occur. It may be executed in a cycle, or may be executed only after the next combustion cycle.

  In the embodiment, the determination of misfire is performed using the secondary coil voltage VC2 reflecting the ionic current. However, other appropriate methods may be used, for example, rotation of the internal combustion engine. It is possible to employ a determination method based on the speed fluctuation state.

  Further, in the embodiment, the drive circuit 3 and ECU 4 for the ignition device are shared with those for the fuel injection valve 5, but it goes without saying that they may be configured separately. In addition, the configuration of the drive circuit 3 shown in the embodiment is merely an example, and switching between application and cutoff of the ignition coil 2 and switching of the applied voltage to the battery voltage and the boosted voltage are controlled by the control of the first and second switching elements. Any configuration can be adopted as long as it is possible. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Spark plug 2 Ignition coil 2b Primary coil 2c Secondary coil 3 Drive circuit 4 ECU (Control means, misfire determination means, secondary coil voltage detection means, boost voltage detection means, application time setting means)
5 Fuel Injection Valve 5a Solenoid 6 Battery 7 Booster Circuit Q1 First Transistor (First Switching Element)
Q2 Second transistor (second switching element)
Q3 Third transistor (third switching element)
Q4 4th transistor (4th switching element)
VIN Primary coil applied voltage VBAT Battery voltage VBST Boost voltage VC2 Secondary coil voltage VREF Threshold (predetermined value)
TEA application time

Claims (4)

An ignition device for an internal combustion engine that ignites an air-fuel mixture in a combustion chamber by an ignition operation in which an induced electromotive force is generated in a secondary coil by sparking a spark with a spark plug by applying and shutting off a voltage to a primary coil of the ignition coil Because
Battery,
A booster circuit for boosting the voltage of the battery;
A first switching element for switching between application and interruption of a voltage to the primary coil;
A second switching element for switching the voltage applied to the primary coil to the battery voltage or a boosted voltage boosted by the booster circuit;
Control means for performing an ignition operation using the battery voltage as an applied voltage of the primary coil as a basic ignition operation by controlling the first and second switching elements;
Misfire determination means for determining whether or not misfire has occurred, and
When it is determined that a misfire has occurred after the basic ignition operation, the control means performs an ignition operation using the boosted voltage as an applied voltage of the primary coil after the basic ignition operation. An ignition device for an internal combustion engine, which is executed as a reignition operation. The internal combustion engine has a fuel injection valve that injects fuel into the combustion chamber by applying a voltage to a solenoid;
A third switching element and a fourth switching element for switching the applied voltage of the solenoid to the battery voltage or the boosted voltage;
The control means controls the first to fourth switching elements to apply the battery voltage or the boosted voltage to the primary coil and the solenoid at different timings, so that the ignition coil and the fuel The ignition device for an internal combustion engine according to claim 1, wherein the injection valve is driven. A secondary coil voltage detecting means for detecting a voltage generated in the secondary coil as a secondary coil voltage;
The internal combustion engine according to claim 1 or 2, wherein the misfire determination means determines that a misfire has occurred when a secondary coil voltage detected after the basic ignition operation is smaller than a predetermined value. Engine ignition device. Boosted voltage detection means for detecting the boosted voltage;
4. An application time setting means for setting an application time of the primary coil for the reignition operation according to the detected boosted voltage, further comprising: An ignition device for an internal combustion engine according to 1.

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