JP4807379B2 - Ignition control device and ignition control system for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition control device for an internal combustion engine, which performs multiple discharge in which ignition discharge at an ignition plug is performed a plurality of times during one combustion stroke.

  In the ignition device provided in the spark ignition type internal combustion engine, for example, in the case of the transistor ignition method, when the electric power charged in the primary side coil of the ignition coil is discharged, the electrode of the ignition plug connected to the secondary side coil In the meantime, an ignition discharge (spark discharge) is performed. In addition, there is a concern that ignition will not occur with only one ignition discharge, and in order to reduce this concern, it has heretofore been known to perform multiple discharge in which ignition discharge is performed a plurality of times during one combustion stroke. ing. This multiple discharge is realized by repeating charging and discharging in the primary coil a plurality of times during one combustion stroke.

For example, in Patent Document 1, when a predetermined time elapses from the start of the first ignition discharge in one combustion stroke, the discharge in the primary coil is stopped to stop the ignition discharge and at the same time, the primary coil is charged. Let it begin. Thereafter, when a predetermined time elapses from the start of the charging, the charging at the primary side coil is switched to discharging and ignition discharge is started. That is, multiple discharge is realized by switching charge and discharge in the primary coil at predetermined time intervals. In the case of the CDI method, multiple discharge is realized by switching charge / discharge with a capacitor every predetermined time.
JP-T-2003-521619

  By the way, normal ignition discharge in the spark plug is discharged from one electrode 15a to the other electrode 15b as indicated by a broken line SP1 in FIG. On the other hand, when a conductive material 15x such as carbon generated during combustion adheres and accumulates on the insulator portion 15c that holds the electrode 15a, the creeping discharge discharges from one electrode 15a to the other electrode 15b through the conductive material 15x. (See the wavy line SP10). However, if the conductive material 15x is burned out by the creeping discharge, the creeping discharge will not occur in the next ignition discharge. Therefore, the creeping discharge is likely to occur at the first time of the multiple discharge, and even in that case, it is highly possible that the ignition discharge will be normal for the second time. And, since the creeping discharge has poor ignitability, the first creeping discharge does not ignite, and there is a high possibility of ignition by the second ignition discharge.

  In short, there is a high probability that ignition due to multiple discharge in which creeping discharge does not occur (hereinafter referred to as “normal ignition”) is performed at the first time of multiple discharge. On the other hand, ignition by multiple discharge in which creeping discharge has occurred (hereinafter referred to as “ignition at abnormal time”) has a high probability of being caused by the second ignition discharge after the first creeping discharge.

  However, in the conventional control in which charging / discharging of the primary side coil is switched every predetermined time as in Patent Document 1, even when useless creeping discharge that is unlikely to contribute to ignition occurs, the creeping discharge is continued for a predetermined time. The Rukoto. Then, since the charge start timing (see symbol t12 in FIG. 3A) required for the primary coil required for the next ignition discharge is delayed, the next ignition discharge start timing (see symbol t13) is delayed. The ignition timing (see symbol ty) is delayed. Then, since the variation between the normal ignition timing (see tx in FIG. 2) and the abnormal ignition timing (ty) increases, the fluctuation in the output torque of the internal combustion engine increases.

  Even if creeping discharge does not occur, the electrodes 15a and 15b are arranged on the locus of the intake air flow (for example, tumble flow or swirl flow) in the combustion chamber or on the injection locus of the fuel injected in the cylinder. The arc due to normal ignition discharge indicated by reference numeral SP1 in FIG. 6B is affected by the intake air flow and the jet flow (see reference numeral F) and is deformed so as to gradually bend and extend each time ignition is repeated. There are cases (see symbols SP2, SP3, SP4). When ignited in a state where such arc elongation occurs, the combustion state becomes excessive as compared with the case where ignition is performed by a normal arc. Therefore, there is a concern that the variation in the combustion state occurs due to the presence or absence of the occurrence of arc elongation and the fluctuation of the output torque of the internal combustion engine becomes large.

  However, in the conventional control in which charging / discharging of the primary side coil is switched every predetermined time as in Patent Document 1, even when arc elongation occurs, the ignition discharge is continued for a predetermined time, and therefore arc elongation occurs. In this state, the possibility of ignition is increased, and as a result, the problem of the output torque fluctuation occurs.

  The present invention has been made to solve the above-described problems, and its object is to ignite an internal combustion engine that suppresses fluctuations in the output torque of the internal combustion engine caused by a discharge abnormality such as creeping discharge or arc elongation. A control device and an ignition control system are provided.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

In the first invention,
Applied to an ignition device comprising an ignition coil composed of a primary coil and a secondary coil, and an ignition plug connected to the secondary coil and ignited between electrodes;
In an ignition control device for an internal combustion engine that controls the operation of the ignition device so as to perform multiple discharge in which the ignition discharge is performed a plurality of times during one combustion stroke of the internal combustion engine,
Based on a secondary current or a secondary voltage flowing between the electrodes of the spark plug, an abnormality detection means for detecting occurrence of a discharge abnormality such as creeping discharge or arc elongation,
When the discharge abnormality is detected, the ignition discharge corresponding to the discharge abnormality is stopped, and the operation of the ignition device is controlled so as to start charging the power required for the next ignition discharge. .

  According to this, since the ignition discharge is stopped when the creeping discharge occurs, it is possible to shorten the implementation period of the useless creeping discharge that is unlikely to contribute to the ignition. In addition, since the ignition discharge is stopped when arc elongation occurs, the possibility of ignition in a state where arc elongation is occurring can be reduced, and as a result, the occurrence of the above-described variation in combustion state due to the presence or absence of arc elongation can be reduced. , Output torque fluctuation can be suppressed.

  Further, according to the present invention, when creeping discharge or arc elongation occurs, the charging required for the next ignition discharge is started, so that the start timing of the next charging (see t12 'in FIG. 4) can be advanced. Therefore, the next ignition discharge timing (see symbol t13 ') can be advanced, and the ignition timing at the time of abnormality (see symbol tz) can be accelerated. As a result, it is possible to reduce the variation between the normal ignition timing (see tx in FIGS. 2 and 4) and the abnormal ignition timing (tz). Therefore, fluctuations in output torque of the internal combustion engine caused by creeping discharge or arc elongation can be suppressed.

In the second invention, the abnormality detecting means is configured to perform the discharge based on a peak value (see reference sign Is in FIG. 4) that appears at the start time of the ignition discharge among the values of the secondary current or the secondary voltage. An abnormality is detected. The present inventors have found that when a discharge abnormality occurs, the peak value is different from the normal value. For example, in the example shown in FIG. 4, when a discharge abnormality occurs, the peak value of the secondary current increases and the peak value of the secondary voltage decreases. Therefore, if a discharge abnormality is detected based on the peak value as in the second aspect , the abnormality can be easily detected.

In the third aspect of the invention, the abnormality detecting means changes a change rate (reference symbol αs in FIG. 4) when the secondary current or the secondary voltage changes from a peak value that appears at the start of the ignition discharge. The discharge abnormality is detected on the basis of the reference). The present inventors have found that when the discharge abnormality occurs, the change rate αs becomes a value different from that at the normal time. For example, in the example shown in FIG. 4, when the discharge abnormality occurs, the change rate αs of the secondary current and the secondary voltage increases (the inclination αs becomes steep). Therefore, if a discharge abnormality is detected based on the rate of change when changing from the peak value as in the third invention , the detection can be facilitated.

In the first place, multiple discharge is intended to eliminate the concern that the probability of non-ignition will increase with only one ignition discharge, but if a discharge abnormality is detected, the number of normal ignition discharges will be reduced. Therefore, the concern cannot be sufficiently resolved. In view of this point, the fourth invention is characterized in that, when the discharge abnormality is detected, the number of ignition discharges performed during one combustion stroke is increased. Can be resolved.

In a fifth aspect of the invention, the number of ignition discharges after the discharge abnormality is detected is set to a preset number. According to this, since the number of normal ignition discharges performed after the discharge abnormality is a preset number, the above-described probability of not igniting can be sufficiently reduced, which is preferable.

In a sixth aspect of the invention, the internal combustion engine is an in-cylinder injection type internal combustion engine that directly injects fuel into a combustion chamber, and an electrode portion that performs the ignition discharge in the ignition plug is disposed on a fuel injection locus. (See FIG. 7). In this case, since the jet directly hits the electrode portion, arc elongation is likely to occur, and a conductive substance such as carbon that is generated during combustion tends to adhere to the spark plug, so that creeping discharge is likely to occur. Therefore, in such an internal combustion engine in which discharge abnormality is likely to occur, the effects of the first to fifth inventions are suitably exhibited.

In a seventh aspect of the invention, the internal combustion engine is an in-cylinder injection type internal combustion engine that directly injects fuel into a combustion chamber, and fuel is injected into the combustion chamber from a fuel injection valve in a plurality of spray patterns, The electrode part which performs the said ignition discharge among the said ignition plugs is arrange | positioned between these spray patterns (refer FIG. 8). In this case, although the degree to which the jet flow directly hits the electrode portion is small as compared with the configuration of the sixth invention , a conductive substance such as carbon generated at the time of combustion easily adheres to the spark plug, so that creeping discharge is likely to occur. . Therefore, in such an internal combustion engine in which discharge abnormality is likely to occur, the effects of the first to fifth inventions are suitably exhibited.

In an eighth aspect of the invention, the internal combustion engine is provided with a supercharger for supercharging the air flowing into the combustion chamber. In this case, since the supercharged intake air having a high flow velocity collides with the spark plug, the arc is likely to be stretched, and the conductive material is also likely to adhere to the spark plug, so that creeping discharge also occurs. It becomes easy. Therefore, in such an internal combustion engine in which discharge abnormality is likely to occur, the effects of the first to fifth inventions are suitably exhibited.

A ninth aspect of the invention is an internal combustion engine ignition control system comprising the ignition control device and the ignition device. According to this ignition control system, the various effects described above can be exhibited in the same manner.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
In this embodiment, an ignition control system is constructed for an in-vehicle gasoline engine that is an internal combustion engine. In the control system, ignition is performed by an ignition plug based on an ignition command from an electronic control unit (hereinafter referred to as ECU). It is supposed to cause discharge (spark). First, the schematic configuration of the ignition control system will be described with reference to FIG.

  In FIG. 1, the ignition coil 10 provided for each cylinder includes a primary coil 10a and a secondary coil 10b. One end of the primary side coil 10a is connected to the high potential (+12 volts) side of the battery 12 via the power supply circuit 11, and the other end is grounded via the IGBT 13 as a switch means. The gate of the IGBT 13 is connected to the ignition control circuit 14, and the IGBT 13 is on / off controlled by the ignition control circuit 14. The secondary coil 10b has one end connected to the spark plug 15 and the other end grounded via a Zener diode 16 and a current detection resistor 17 (shunt resistor). The output of the current detection resistor 17 is input to the ignition control circuit 14. Here, the output voltage of the power supply circuit 11 is Vo, and the currents flowing through the primary side coil 10a and the secondary side coil 10b are the primary current I1 and the secondary current I2, respectively.

  As is well known, the ECU 20 is mainly composed of a microcomputer including a CPU, RAM, ROM, and the like, and controls various operating states of the engine by executing various control programs stored in the ROM. In the ignition timing control, the ECU 20 acquires operating state information representing the operating state of the engine such as the engine speed and the accelerator operation amount, and calculates an optimal ignition timing based on the operating state information. Then, an ignition signal IGt is generated according to the ignition timing and output to the ignition control circuit 14. Further, in the present ignition control system, multiple discharge control is performed in which ignition discharge is generated in the spark plug 15 a plurality of times within one combustion stroke in order to improve the combustion state. For this reason, ECU20 calculates the multiple discharge period which repeatedly produces ignition discharge based on driving | running state information. Then, a multiple period signal IGw that defines the multiple discharge period is generated and output to the ignition control circuit 14.

  The ignition control circuit 14 outputs a drive signal IG for turning on / off the IGBT 13 based on the ignition signal IGt and the multiple period signal IGw input from the ECU 20. Specifically, the IGBT 13 is turned on / off according to the ignition signal IGt, and the first ignition discharge is generated at the ignition timing. Thereafter, the IGBT 13 is repeatedly turned on / off during the multiple discharge period by the multiple period signal IGw, and the ignition plug 15 is repeatedly caused to generate ignition discharge. An outline of such multiple discharge operation will be described with reference to the time chart of FIG. However, FIG. 2 is a time chart when a normal discharge is performed. When the occurrence of a discharge abnormality, which will be described in detail later, is detected, the operation of the multiple discharge is controlled so that the time chart shown in FIG. 4 is obtained. Is done.

  In FIG. 2 relating to normal discharge, the first ignition discharge is generated at the timing t11 as the ignition timing, and the ignition discharge is repeatedly generated between the timings t11 to t14 as the multiple discharge period. Here, a configuration in which the IGBT 13 is turned on / off at every constant switching time Tb, Tc will be described.

  First, at the timing t10 before the ignition timing, when the ignition signal IGt is raised to H level, the drive signal IG is raised to H level and the IGBT 13 is turned on. As a result, the primary current I1 flows through the primary coil 10a, and the ignition coil 10 is charged. Thereafter, when the ignition signal IGt falls to the L level at the timing t11 that is the ignition timing, the drive signal IG falls to the L level and the IGBT 13 is turned off. Thereby, the first ignition discharge is generated in the spark plug 15 with the discharge of the ignition coil 10.

  Further, at the timing t11, the multi-period signal IGw is raised to the H level. For this reason, at timing t12 when the switching time Tb has elapsed from timing t11, the drive signal IG is raised to the H level, and the IGBT 13 is turned on. As a result, the primary current I1 flows again in the primary coil 10a, and the ignition coil 10 is recharged. Further, when the switching time Tc elapses and the timing t13 is reached, the drive signal IG falls to the L level, and the IGBT 13 is turned off. As a result, ignition discharge occurs again in the spark plug 15.

  Thereafter, until the multi-period signal IGw falls to the L level at timing t14, the H / L level of the drive signal IG is switched for each switching time Tb, Tc, and the IGBT 13 is turned on / off. Thereby, ignition discharge is repeatedly generated in the spark plug 15 during the multiple discharge period. In addition, there is a high probability that the ignition by the multiple discharge in which creeping discharge does not occur (ignition at normal time) is performed at the first time of the multiple discharge. In that case, there is a high probability of ignition at the time when the discharge is sufficiently performed in the discharge period tb, that is, the time near the discharge end time t12 (the time indicated by the symbol tx).

  Incidentally, in addition to controlling to perform multiple discharge by switching the H / L level of the drive signal IG every time the switching times Tb and Tc elapse as described above, the following control may be performed. In other words, the discharge at the ignition coil 10 is cut at the timing t12 when it is detected that the value of the secondary current I2 that has fallen due to the ignition discharge has risen to a preset cut current value Ic. Switch to charge. Then, after starting charging, discharging of the ignition coil 10 is switched to charging at timing t13 when the switching time Tc has elapsed.

  As described above, the above-described creeping discharge (see FIG. 6A) occurs in the control for switching on / off of the IGBT 13 for each constant switching time Tb, Tc or the control for switching based on the cut current value Ic. In such a case, the following problems occur.

  FIG. 3A shows a malfunction in the case where creeping discharge occurs during the first ignition discharge. In this case, useless creeping discharge that is unlikely to contribute to ignition is continued for a predetermined time Tb. It becomes. Then, since the charging start timing t12 in the primary side coil 10a required for the next ignition discharge becomes uselessly delayed, the next discharge start timing t13 in the primary side coil 10a also becomes uselessly delayed. Therefore, since the ignition discharge start timing t13 in the secondary side coil 10b next time is delayed, the abnormal ignition timing ty is unnecessarily delayed. As a result, the variation between the normal ignition timing tx (see FIG. 2) and the abnormal ignition timing ty increases, and the fluctuation in the output torque of the internal combustion engine increases.

  FIG.3 (b) has shown the malfunction when arc elongation arises at the time of the first ignition discharge, and when it ignites in the state where such arc elongation has arisen, it is excessive compared with the case where it ignites by normal arc. It becomes a combustion state. Therefore, there is a concern that the variation in the combustion state occurs due to the presence or absence of the occurrence of arc elongation and the fluctuation of the output torque of the internal combustion engine becomes large. In addition, in the example of FIG. 3B, the ignition discharge in a state where the arc stretch has occurred is continued for a predetermined time Tb, so that the possibility of ignition in a state in which the arc stretch has occurred becomes high. The problem of the output torque fluctuation occurs.

  Therefore, when detecting the occurrence of a discharge abnormality such as creeping discharge or arc elongation, the ignition control circuit 14 in the present embodiment immediately stops the ignition discharge corresponding to the discharge abnormality and charges the power required for the next ignition discharge. Start immediately. Hereinafter, a method of detecting the occurrence of discharge abnormality performed by the present embodiment will be described.

  When creeping discharge occurs as shown in FIG. 3A, the peak value of the secondary voltage V2 and the sustain voltage are Vps, Vp, Vh compared to normal values Vp, Vh due to the longer discharge path. It becomes small to Vhs. Further, the peak value of the secondary current I2 and the slope (change rate) when rising from the peak value become larger to Ips and αs than the normal values Ip and α (α = ΔI / Δt). Incidentally, the sustain voltage Vh is a voltage required to maintain the arc.

  When arc elongation occurs as shown in FIG. 3 (b), the peak value and sustain voltage of the secondary voltage V2 are normal values Vp, It becomes smaller to Vpt and Vhs compared to Vh. Further, the peak value of the secondary current I2 and the slope (change rate) when rising from the peak value become larger to Ipt and αt than the normal values Ip and α (α = ΔI / Δt).

  As described above, when discharge abnormalities such as creeping discharge and arc elongation occur, the inventor changes that the peak value Vp and sustain voltage Vh of the secondary voltage V2 and the peak value Ip and slope α of the secondary current I2 change. Found. Therefore, in the present embodiment, whether or not discharge abnormality has occurred is detected based on at least one of these values. FIG. 4 is a time chart showing the ignition operation according to the present embodiment at the time of abnormal discharge, detecting the abnormal discharge at timing t12 ′ during the first ignition discharge period, and switching from discharging to charging at the timing t12 ′. .

  FIG. 5 is a flowchart showing a processing procedure of ignition control executed by the ignition control circuit 14 (or a microcomputer included in the ECU 20), and is repeated every predetermined time (for example, calculation processing time of the CPU) or every predetermined crank angle. Executed. Note that at least one of the ignition control circuit 14 and the ECU 20 corresponds to an “ignition control device” described in the claims.

  First, when the ignition signal IGt is turned on (H level) from the ECU 20 in step S10, the drive signal IG is turned on (H level) (step S11), and a flag indicating that charging of the ignition coil 10 has started is set. (Step S12). In the subsequent step S13, it is determined whether or not a preset charging time Tc (normal charging period) has elapsed since the timing t10 when the drive signal IG was turned on.

  When it is determined that the charging time Tc has passed, a flag is set to end charging the ignition coil 10 at the determination timing t11 (step S14), and the drive signal IG is turned off (L level). (Step S15).

  Thereafter, in steps S20 and S30 (abnormality detection means), it is determined whether or not creeping discharge or arc elongation has occurred. In step S20, it is determined whether or not the value of the secondary current I2 is higher than the secondary current peak value Ip. Thereafter, in step S30, the gradient α when the secondary current I2 increases from the peak value of the secondary current I2. It is determined whether (α = ΔI / Δt) is smaller than the threshold value a.

  That is, as indicated by the symbol Ip in FIGS. 2 and 3, the peak value appearing at the timing t11 at which the ignition discharge is started among the values of the secondary current I2 is I2 <Ip when the discharge is normal. Therefore, if a negative determination is made in step S20 (I2 ≧ Ip), it is considered that creeping discharge or arc elongation has occurred, and the process proceeds to steps S21 to S26.

  Further, the slope α when the value of the secondary current I2 rises from the peak value should be α <a during normal discharge, and therefore when negative determination is made in step S30 (α ≧ a). In addition, assuming that creeping discharge or arc elongation has occurred, the process proceeds to steps S21 to S26.

  If it is determined in steps S20 and S30 that the discharge is abnormal, the drive signal IG is turned on (H level) (step S21), and a flag indicating that charging of the ignition coil 10 has been started is set (step S22). Next, the number of abnormal discharge times IGE is incremented by one (step S23), and it is determined whether or not the abnormal discharge number IGE is equal to or less than a predetermined number (here, 2 times) (step S24). If it is determined that IGE ≦ 2, the count number of the specified number of discharges IGSN is added by one (step S25), and in the subsequent step S26, it is set in advance from the timing t12 ′ at which the discharge is cut with the detection of the abnormal discharge. It is determined whether or not the charging time Tcf has elapsed.

  When it is determined that the charging time Tcf has elapsed (T = Tcf), the process returns to step S14, and a flag is set to end charging the ignition coil 10 at the determination timing t13 ′ (step S14). ) And the drive signal IG is turned off (L level) (step S15). In other words, the number of ignition discharges after the abnormal discharge is detected is set to be a predetermined number (three in this case) by the processes in steps S23 to S25.

  On the other hand, if the discharge abnormality is not determined in steps S20 and S30, it is determined whether or not the value of the secondary current I2 has increased to the cut current value Ic (step S31). If a negative determination is made in step S31, the process returns to step S30. If an affirmative determination is made in step S31 (I2 = Ic), the process proceeds to step S32 and the count number of normal discharge times IGS is set to one. to add. In a succeeding step S33, it is determined whether or not the normal discharge number IGS has reached the specified discharge number IGSN.

  If an affirmative determination is made in step S33 (IGS = IGSN), the series of processes shown in FIG. 5 is terminated, and if a negative determination is made, the process is preset from timings t11 and t13 at which discharge is started. It is determined whether or not the charging time Tb has elapsed (step S34). When it is determined that the discharge time Tb has elapsed, the process returns to step S11, the drive signal IG is turned on (H level) at the determination timing t12 (step S11), and the ignition coil 10 is charged. A flag indicating that it has started is set (step S12).

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) In the first ignition discharge period of multiple discharges, the creeping discharge is detected at the timing t12 ′ and at the same time the initial ignition discharge is stopped. Therefore, the implementation period of useless creeping discharge that is unlikely to contribute to ignition is shortened. it can. That is, when ignition discharge is performed until the charging time Tb elapses, the creeping discharge execution period is tb (see FIG. 3), whereas according to the present embodiment, the creeping discharge execution period is tbf (see FIG. 3). 4).

  In addition, since the first ignition discharge is stopped at the same time as detecting the arc elongation at timing t12 ′, the possibility of ignition in the state where the arc elongation is occurring can be reduced, and as a result, the variation in the combustion state due to the presence or absence of the occurrence of the arc elongation can be reduced. Generation can be reduced and fluctuations in output torque can be suppressed.

  (2) Since the charging required for the next ignition discharge is started simultaneously with the detection of the creeping discharge or the arc elongation, the start timing of the next charging can be made earlier. That is, when ignition discharge is performed until the charging time Tb elapses, the next charging start timing is t13 (see FIG. 3), but according to the present embodiment, the next charging start timing is t13 ′ ( (See FIG. 4). Therefore, the next ignition discharge timing t13 'can be advanced, and the abnormal ignition timing tz (see FIG. 4) can be accelerated. As a result, it is possible to reduce the variation between the normal time ignition timing tx and the abnormal time ignition timing tz. Therefore, fluctuations in output torque of the internal combustion engine caused by creeping discharge or arc elongation can be suppressed.

  (3) When the discharge abnormality occurs, the peak value Is of the secondary current increases, and the increase rate αs of the secondary current peak value that appears at the start of ignition discharge becomes steep, and the peak value Since the discharge abnormality is detected based on Is and the change speed αs, the abnormality can be easily detected. It should be noted that a discharge abnormality can be detected based on the peak value of the secondary voltage and the sustain voltages Vp and Vh, but in that case, the voltage between the electrodes of the spark plug must be detected as the secondary voltage. However, since a large noise accompanying the spark is superimposed on the detected value, there is a concern about a decrease in abnormality detection accuracy. In this respect, according to the present embodiment in which the abnormality detection is performed based on the secondary current, the abnormality detection accuracy can be improved as compared with the case where the abnormality detection is performed based on the secondary voltage.

  (4) In the first place, the multiple discharge is intended to eliminate the concern that the probability of non-ignition will increase with only one ignition discharge. Therefore, in the present embodiment, the number of ignition discharges during the multiple discharge period is variably set so that the number of ignition discharges after the abnormal discharge is detected becomes a predetermined number. Therefore, the “probability of not igniting” can be sufficiently reduced, and the above-mentioned concerns can be suitably solved.

(Second Embodiment)
The ignition control system according to the present embodiment is applied to a spray guide type in-cylinder injection internal combustion engine as illustrated in FIG. In addition, the structure and control content of the ignition control system according to the present embodiment are the same as those in the first embodiment.

  In the spray guide system, when fuel is directly injected from the fuel injection valve 21 into the cylinder, the fuel spray is injected during the compression stroke so that the air-fuel ratio becomes leaner than the stoichiometric air-fuel ratio. This is a method of performing ignition when the shaded portion 21a) passes near the electrodes 15a and 15b (see FIG. 6) of the spark plug 15, and is applied to an internal combustion engine capable of stratified lean combustion.

  In such an internal combustion engine, the electrodes 15a and 15b are arranged on the fuel injection locus 21a. Then, as described above with reference to FIG. 6B, the arc SP1 due to the normal ignition discharge is easily affected by the jet F and the arc elongation SP2, SP3, SP4 is likely to occur. In addition, since a conductive substance such as carbon generated during combustion easily adheres to the spark plug, creeping discharge is likely to occur. Therefore, according to this embodiment in which the ignition control system similar to the first embodiment is applied to the internal combustion engine in which arc elongation and creeping discharge are likely to occur, the various effects described in the first embodiment are suitable. To be demonstrated.

  Further, as illustrated in FIG. 7, the ignition control system according to the present embodiment is applied to an internal combustion engine provided with a supercharger 22 that supercharges intake air using exhaust as a driving force. In such an internal combustion engine, arc elongations SP2, SP3, and SP4 are likely to occur due to the influence of the supercharged intake air flow. Therefore, according to this embodiment in which the ignition control system similar to that of the first embodiment is applied to the internal combustion engine in which arc elongation is likely to occur, various effects described in the first embodiment are suitably exhibited. The

(Third embodiment)
In the second embodiment, the electrodes 15a and 15b of the spark plug 15 are applied to the internal combustion engine disposed on the fuel injection locus 21a. In the present embodiment illustrated in FIG. Although 15a and 15b deviate from the fuel injection locus 21a, the fuel is injected from the fuel injection valve 21 in a plurality of spray patterns 21b, and the electrode portions 15a and 15b are connected to the plurality of spray patterns 21b. Arranged between. In addition, FIG.8 (b) is A arrow directional view of (a).

  Even in the internal combustion engine having such a configuration, a conductive substance such as carbon that is generated during combustion is likely to adhere to the spark plug, so that creeping discharge is likely to occur. Therefore, according to this embodiment in which the ignition control system similar to that of the first embodiment is applied to the internal combustion engine in which creeping discharge is likely to occur, various effects described in the first embodiment are suitably exhibited. The

(Fourth embodiment)
In the ignition control system according to the first embodiment, a transistor ignition system for supplying electric energy from the power supply circuit 11 to the ignition coil 10 is adopted, whereas in the present embodiment shown in FIG. (Capacitive discharge ignition circuit) and a CDI ignition system for supplying electric energy from the power supply circuit 11 are employed. That is, in the first embodiment, the ignition coil 10 is charged and discharged by turning on / off the IGBT 13 (switch means), and the ignition plug 15 repeatedly generates ignition discharge by the charge and discharge, thereby performing multiple discharge. Has been implemented. On the other hand, in the present embodiment, the energy storage coil 31 is charged and discharged by turning on / off the IGBT 13, and multiple discharge is performed by repeatedly generating ignition discharge in the spark plug 15 by the charge and discharge.

  In FIG. 9, the symbols and the like used in FIG. 1 are applied mutatis mutandis, and differences from FIG. 1 will be described below. In FIG. 9, a CDI circuit A is connected to the primary coil 10 a in parallel with the power supply circuit 11. That is, as the CDI circuit A, the energy storage coil 31 and the IGBT 32 are connected in series to the battery 12. Electric energy is stored in the energy storage coil 31 when the IGBT 32 is turned on by the drive signal DS. A capacitor 34 is connected between the energy storage coil 31 and the IGBT 32 via a diode 33. The capacitor 34 is charged with electric energy stored in the energy storage coil 31. The capacitor 34 is connected to the primary coil 10a.

  Further, a backflow preventing diode 35 is added between the power supply circuit 11 and the primary coil 10. On the other hand, the zener diode 16 connected to the secondary coil 10b is removed, and the secondary coil 10b and the current detection resistor 17 are connected.

  In such a configuration, the IGBT 32 is on / off controlled by the ignition control circuit 14. The IGBT 32 of the CDI circuit A is controlled to be turned on / off oppositely to the IGBT 13 connected to the primary coil 10a. Thus, when the IGBTs 13 and 32 are repeatedly turned on / off in the multiple discharge period, the positive / negative secondary current I2 flows through the secondary coil 10b, and ignition discharge is continuously generated in the spark plug 15.

  Even in the ignition control system including such a CDI circuit, when the discharge abnormality is detected during charging / discharging of the ignition coil 10, the ignition discharge is stopped and the charge required for the next ignition is started, thereby enabling the above-described first embodiment. Similar effects are exhibited.

(Other embodiments)
The above embodiments may be implemented with the following modifications. Further, the present invention is not limited to the description of the above embodiment, and the characteristic configurations of the respective embodiments may be arbitrarily combined.

  In the above embodiment, the secondary current I2 flows from the spark plug 15 toward the secondary coil 10b, but the secondary current I2 flows from the secondary coil 10b toward the spark plug 15. You may comprise as follows. In that case, the waveforms of the secondary current I2 and the secondary voltage V2 shown in FIGS. 2 and 4 are inverted up and down. Therefore, for example, referring to the secondary current I2, when discharge abnormality occurs, the peak values Ips and Ipt of the secondary current I2 become low and the changes αs and αt of the secondary current I2 become small. .

  In the first embodiment, when there is no discharge abnormality, control is performed so that multiple discharges are performed by switching the H / L level of the drive signal IG every time the switching times Tb and Tc elapse. In addition to the control, the following control may be performed. That is, the discharge at the ignition coil 10 is cut at the timing when it is detected that the value of the secondary current I2 that has fallen due to the ignition discharge has risen to a preset cut current value Ic. Switch to charging. Then, after starting charging, discharging of the ignition coil 10 is switched to charging at timing t13 when the switching time Tc has elapsed. In this case, the charging period has a length indicated by a symbol tb 'in FIG.

  In the first embodiment, the battery 12 is used as the power source, and the primary coil 10a and the energy storage coil 31 are charged by the power supply from the battery 12, but this configuration is changed. For example, when a power generation device including an AC generator or a regulator is provided as a power source, the primary side coil 10a and the energy storage coil 31 may be charged with power generated by the power generation device.

The block diagram which shows the outline of the ignition control system concerning 1st Embodiment of this invention. In 1st Embodiment, the time chart which shows the ignition operation in case discharge abnormality has not generate | occur | produced. (A) is a time chart for demonstrating the malfunction by creeping discharge generation | occurrence | production, (b) is a time chart for demonstrating the malfunction by arc elongation generation | occurrence | production. The time chart which shows the ignition operation at the time of discharge abnormality by the ignition control of 1st Embodiment. The flowchart which shows the process sequence for performing the ignition control of FIG. (A) is a figure explaining the phenomenon of creeping discharge, (b) is a figure explaining the phenomenon of arc elongation. It is a block diagram which shows the outline of an internal combustion engine to which the ignition control system concerning 2nd Embodiment of this invention is applied. It is a block diagram which shows the outline of the internal combustion engine to which the ignition control system concerning 3rd Embodiment of this invention is applied. It is a block diagram which shows the outline of the ignition control system concerning 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Ignition coil, 10a ... Primary side coil, 10b ... Secondary side coil, 14 ... Ignition control circuit (ignition control device), 15 ... Spark plug, 20 ... ECU (ignition control device), S20, S30 ... Abnormality detection means .

Claims (9)

Applied to an ignition device comprising an ignition coil comprising a primary side coil and a secondary side coil, and an ignition plug connected to the secondary side coil and igniting discharge between the electrodes, during one combustion stroke of the internal combustion engine In the ignition control device for an internal combustion engine that controls the operation of the ignition device so as to perform multiple discharge for performing the ignition discharge a plurality of times,
Occurrence of discharge abnormalities such as creeping discharge or arc elongation based on the rate of change when changing from the peak value that appears at the start of the ignition discharge among changes in the secondary current or secondary voltage flowing between the electrodes of the spark plug An abnormality detection means for detecting
When the discharge abnormality is detected, the ignition discharge corresponding to the discharge abnormality is stopped, and the operation of the ignition device is controlled so as to start charging the power required for the next ignition discharge. An ignition control device for an internal combustion engine. The discharge when an abnormality is detected, one of the ignition control system for an internal combustion engine according to claim 1, wherein increasing the number of said ignition discharge that takes place during the combustion stroke.   Applied to an ignition device comprising an ignition coil comprising a primary side coil and a secondary side coil, and an ignition plug connected to the secondary side coil and igniting discharge between the electrodes, during one combustion stroke of the internal combustion engine In the ignition control device for an internal combustion engine that controls the operation of the ignition device so as to perform multiple discharge for performing the ignition discharge a plurality of times,
  Based on a secondary current or a secondary voltage flowing between the electrodes of the spark plug, an abnormality detection means for detecting occurrence of a discharge abnormality such as creeping discharge or arc elongation,
  When the discharge abnormality is detected, the ignition discharge corresponding to the discharge abnormality is stopped, and the operation of the ignition device is controlled so as to start charging the electric power required for the next ignition discharge, so that one combustion is performed. An ignition control device for an internal combustion engine, wherein the number of ignition discharges performed during a stroke is increased. The ignition control device for an internal combustion engine according to claim 2 or 3 , wherein the number of times of the ignition discharge after the discharge abnormality is detected is set to a preset number. 5. The abnormality detection unit according to claim 1, wherein the abnormality detection unit detects the discharge abnormality based on a peak value that appears at a start time of the ignition discharge among values of the secondary current or the secondary voltage . The internal combustion engine ignition control device according to any one of the above. The internal combustion engine is a direct injection internal combustion engine that directly injects fuel into a combustion chamber,
The ignition control device for an internal combustion engine according to any one of claims 1 to 5, wherein an electrode portion that performs the ignition discharge in the ignition plug is disposed on a fuel injection locus. The internal combustion engine is a direct injection internal combustion engine that directly injects fuel into a combustion chamber,
Fuel is injected from the fuel injection valve into the combustion chamber in a plurality of spray patterns,
The ignition control device for an internal combustion engine according to any one of claims 1 to 5, wherein an electrode portion that performs the ignition discharge in the ignition plug is disposed between the plurality of spray patterns. .   The ignition control device for an internal combustion engine according to any one of claims 1 to 7, wherein the internal combustion engine is provided with a supercharger that supercharges the air flowing into the combustion chamber.   An ignition control system for an internal combustion engine, comprising: the ignition control device according to any one of claims 1 to 8; and the ignition device.

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