JP6685444B2 - Ignition device for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition device for an internal combustion engine mounted on a motor vehicle, and obtains good discharge characteristics by superimposing an increase in discharge energy generated on the secondary side of an ignition coil.

  As internal combustion engines installed in vehicles, direct injection engines and high EGR engines are used to improve fuel efficiency. However, since these engines do not have very good ignitability, a high energy type ignition device is required. Become. Therefore, a phase discharge type ignition device has been proposed in which the output of another ignition coil is additionally superimposed on the secondary output of the ignition coil generated by the classical current cutoff principle (for example, Patent Document 1). See).

  According to the ignition device described in Patent Document 1, a high voltage of several kV generated on the secondary side of the main primary ignition coil by cutting off the primary current causes a dielectric breakdown in the discharge gap of the spark plug. After the discharge current starts to flow from the secondary side of the ignition coil, the primary current of the auxiliary ignition coil connected in parallel with the main ignition coil is cut off, and the DC voltage of several kV generated on the secondary side is added. By superimposing them, a large amount of discharge energy can be given to the spark plug over a relatively long period of time, so that the ignitability of the fuel is improved and the fuel consumption is also improved.

JP2012-140924A

  However, in the system such as the ignition device described in Patent Document 1, since the discharge current of the spark plug is determined by the combination of the triangular currents output from the coils, in order to extend the high current period, two It is necessary to increase the ignition phase of the ignition coils and to lengthen the time for accumulating sufficient energy in the two ignition coils. As described above, if the energization time to the primary coil is increased in addition to the use of the two ignition coils, there arises a problem that the coil main body becomes large and the heat generated by the switching element for controlling the energization to the primary coil becomes high.

  Further, as a method of increasing the energy stored in the primary coil without increasing the energization time to the primary coil, a method of increasing the stored energy by enlarging the size of the coil and a method of using a plurality of ignition coils can be considered. However, if a large ignition coil is used or a plurality of ignition coils are used, securing a mounting space becomes a problem.

  Furthermore, by boosting the power supply voltage outside or inside the ignition coil and applying a high voltage directly to the secondary side of the coil, the discharge energy of the secondary side can be increased without increasing the energization time to the primary coil. It is also possible to increase the However, in such a method, since the power supply voltage must be boosted to about several kV, it is necessary to increase the withstand voltage of the booster circuit to be mounted and to withstand the connection at a high voltage, resulting in a considerable increase in cost.

  Therefore, the present invention can secure a stable high current period and maintain combustion without prolonging the energization time to the main primary coil, and can suppress an increase in size of the ignition coil and a significant increase in cost. An object is to provide an ignition device for an internal combustion engine.

In order to solve the above-mentioned problems, the invention according to claim 1 provides a main primary coil in which a forward magnetic flux is increased by energization and a forward magnetic flux is reduced by interrupting an electric current, and the main primary coil. Separately provided, a secondary primary coil that generates a magnetic flux in the same forward direction as the primary primary coil when energized, and one end side is connected to an ignition plug, and the magnetic flux generated in the primary primary coil and the secondary primary coil acts to discharge energy. An ignition coil having a secondary coil for generating electricity; a main switch means for switching energization / interruption from a battery to the main primary coil; and a sub switch means for switching energization / interruption from the battery to the sub primary coil. An ignition control means for controlling the main switch means and the auxiliary switch means to generate a discharge spark at an ignition plug at a predetermined timing of a combustion cycle. The ignition control means is capable of performing normal discharge control for generating discharge energy in a secondary coil by controlling energization / interruption of the main primary coil, and the main primary coil and the sub-igniter coil. It is characterized by enabling superimposition discharge control before ignition timing, which controls simultaneous energization and interruption of electricity.

  According to the internal combustion engine ignition device of the present invention, since it is possible to perform pre-ignition timing superimposition discharge control, it is possible to superimpose necessary and sufficient discharge energy according to the operating conditions from the sub primary coil to the secondary coil. A stable high current period is secured without prolonging the energization time to the primary coil, and suitable combustion is realized.

1 is a schematic configuration diagram showing a first embodiment of an internal combustion engine ignition device according to the present invention. FIG. 3 is a waveform diagram schematically showing waveforms of various parts in a combustion cycle when main normal discharge control is performed by the internal combustion engine ignition device according to the first embodiment. FIG. 5 is a waveform diagram schematically showing waveforms of various parts in a combustion cycle when performing pre-ignition timing superimposed discharge control by the internal combustion engine ignition device according to the first embodiment. FIG. 3 is a waveform diagram schematically showing waveforms of various parts in a combustion cycle when performing post-ignition superimposed discharge control by the internal combustion engine ignition device according to the first embodiment. FIG. 4 is a waveform diagram schematically showing waveforms of respective parts in a combustion cycle when performing pre-ignition timing superposed discharge control and post-ignition timing superposed discharge control by the internal combustion engine ignition device according to the first embodiment. It is a schematic block diagram which shows 2nd Embodiment of the internal combustion engine ignition device which concerns on this invention. It is a schematic block diagram which shows 3rd Embodiment of the ignition device for internal combustion engines which concerns on this invention. It is a wave form diagram which showed typically each part waveform in a combustion cycle when performing subordinary electric discharge control by an internal combustion engine ignition device concerning a 3rd embodiment.

  Next, an embodiment of an internal combustion engine ignition device according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an ignition device 1 for an internal combustion engine according to a first embodiment of the present invention, and an ignition coil unit 10 for generating a discharge spark in one spark plug 2 provided for each cylinder of the internal combustion engine, Internal combustion engine drive control device 3 provided with an ignition control means 31 for outputting an ignition signal Si or the like for instructing the operation timing of the ignition coil unit 10, a DC power source 4 such as a vehicle battery, a secondary primary coil magnetic flux generation state It is composed of the switching unit 5 and the like.

  In the internal combustion engine ignition device 1 according to the present embodiment, the ignition control means 31 is included in the internal combustion engine drive control device 3 that comprehensively controls the internal combustion engine of the automobile, but is not limited thereto. Not something. For example, it receives an ignition signal generated by an ignition signal generation function of a normal internal combustion engine drive control device 3, and outputs an appropriate control signal to the ignition coil unit 10 and the sub primary coil magnetic flux generation state switching unit 5. The ignition control means may be provided separately.

  In the ignition coil unit 10, for example, the ignition coil 11, the main switch element 12, the bypass line 13 provided in parallel with the main switch element 12, the rectifying means 14 provided in the bypass line 13 and the like are housed in a case 15 having a predetermined shape. It is an integrated structure unit. A high-voltage terminal 151 and a connector 152 are provided at appropriate places of the case 15, and the spark plug 2 is connected via the high-voltage terminal 151, and the connector 152 (for example, the first connection terminal 152a to the sixth connection terminal 152f are connected to each other). The internal combustion engine drive control device 3, the DC power source 4 such as a vehicle battery, the sub primary coil magnetic flux generation state switching unit 5, and the ground point GND are connected via a connector provided therein.

  The ignition coil 11 includes a main primary coil 111a (for example, 90 turns), a sub primary coil 111b (for example, 60 turns), and a secondary coil 112 (for example, 9000 turns). The ignition coil 11 causes the magnetic flux generated in the main primary coil 111a and the sub primary coil 111b to act on the secondary coil 112. For example, the main primary coil 111a and the sub primary coil 111b are arranged so as to surround the center core 1113. Then, the secondary coil 112 is arranged on the outer side thereof.

  One end of the main primary coil 111a is connected to the DC power supply 4 via the second connection terminal 152b, for example, and a power supply voltage VB + (for example, 12V) is applied. The other end of the main primary coil 111a is connected to the ground point GND via the main switch element 12 and the fifth connection terminal 152e.

  The main switch element 12 is a main switch means for turning on / off the main primary coil 111a, and is configured by using, for example, an IGBT (Insulated Gate Bipolar Transistor). That is, the ignition coil unit 10 has a unit structure in which the ignition coil and the igniter are sealed in the case 15. The gate G, which is a control terminal of the main switch element 12, is connected to the internal combustion engine drive control device 3 via, for example, the fourth connection terminal 152d, and is ON / OFF controlled by the ignition signal Si generated by the ignition control means 31. It

  As described above, when the main switching element 12 is turned on by the ignition signal Si and the main primary coil 111a is energized, the main primary current I1a flows, the forward magnetic flux increases, and the main switching element 12 turns off. Then, when the main primary current I1a is cut off, the forward magnetic flux is rapidly reduced, and a high voltage is generated on the secondary coil 112 side so as to generate a magnetic field in a direction that obstructs this magnetic flux change. A discharge spark is generated in the discharge gap of the spark plug 2 and a secondary current I2 flows. The control for discharging the spark plug 2 by the energization / interruption control for the main primary coil 111a is hereinafter referred to as main normal discharge control.

  The secondary coil 112 has one end connected to the spark plug 2 via the high-voltage terminal 151 and the other end connected to the ground point GND via the sixth connection terminal 152f. A current detection resistor 61 is provided between the sixth connection terminal 152f and the ground point GND so that the secondary current detection signal Di2 is supplied to the internal combustion engine drive control device 3.

  The internal combustion engine drive control device 3 can know the operating condition of the engine by monitoring the secondary current I2, and together with other information such as the number of revolutions of the engine, check whether the discharge energy in the cylinder is excessive or insufficient. If the discharge energy applied to the secondary coil 112 is insufficient, the discharge energy is increased, and conversely, if the discharge energy applied to the secondary coil 112 is excessive, the discharge energy is appropriately reduced. , High fuel efficiency improvement effect can be expected. For this reason, the ignition control means 31 of the internal combustion engine drive control device 3 controls the operation of the sub primary coil magnetic flux generation state switching unit 5 so that an appropriate magnetic flux is generated from the sub primary coil 111b at an appropriate timing. is there.

  Here, the sub-primary coil 111b whose energization direction and energization / interruption timing are controlled by the sub-primary coil magnetic flux generation state switching unit 5 will be described.

  A magnetic flux in the forward direction is generated in the sub primary coil 111b by energization in a predetermined first direction (for example, a direction from the first end 111b1 which is one end of the sub primary coil 111b to the second end 111b2 which is the other end). Magnetic flux generated in the opposite second direction (for example, the direction from the second end 111b2 to the first end 111b1) in the opposite direction to the forward direction (magnetic field generated on the secondary side by the main normal discharge control) Magnetic flux in the same direction as) occurs.

  Then, the first end 111b1 of the sub primary coil 111b is connected to the sub primary coil magnetic flux generation state switching unit 5 via, for example, the third connection terminal 152c, and the second end 111b2 of the sub primary coil 111b is connected to, for example, the first connection. The secondary primary coil magnetic flux generation state switching unit 5 is connected via the terminal 152a. Therefore, when the sub primary coil magnetic flux generation state switching unit 5 sets the first end 111b1 of the sub primary coil 111b to the power feeding side and the second end 111b2 to the ground side, the sub primary coil 11b is energized in the first direction. Becomes Conversely, when the sub-primary coil magnetic flux generation state switching unit 5 sets the second end 111b2 of the sub-primary coil 111b to the power supply side and the first end 111b1 to the ground side, the sub-primary coil 11b is energized in the second direction. It will be.

  The first direction and the second direction of the sub primary coil 111b are determined by the arrangement state with the main primary coil 111a. For example, when the winding direction of the sub primary coil 111b and the winding direction of the main primary coil 111b are arranged to be the same, if the same direction as the energization direction to the main primary coil 111b is set as the first direction A forward magnetic flux is generated in the sub primary coil 111b. Conversely, when the winding direction of the sub primary coil 111b and the winding direction of the main primary coil 111b are arranged so as to be opposite to each other, the main primary coil 111b is energized with the opposite direction as the first direction. For example, a forward magnetic flux is generated.

  When the sub primary coil 111b configured as described above is energized in the first direction at the same timing as the main normal discharge control by the main primary coil 111a described above, a magnetic flux in the same forward direction as the main primary coil 11a is generated. After that, if the energization to the secondary primary coil 111b is interrupted at the same timing as the main normal discharge control, the forward magnetic fluxes of the primary primary coil 111a and the secondary primary coil 111b decrease rapidly at the same time, so the discharge energy applied to the secondary side is reduced. Can be increased. That is, a forward magnetic flux is generated by the sub-primary coil 111b before the ignition timing (before the energization cutoff to the main primary coil 111a), and the energization cutoff to the sub-primary coil 111b is performed simultaneously with the main primary coil 111a. For example, the secondary primary coil 111b can superimpose the discharge energy on the secondary coil 112.

  Further, when the secondary primary coil 111b is energized in the second direction at an appropriate timing after the ignition timing (after the timing of interrupting energization of the primary primary coil 111a), the magnetic flux in the opposite direction (higher to the secondary side) is generated. Since it is possible to prevent the secondary side magnetic field from being attenuated and the secondary side electromotive force from being lowered, it is possible to prevent the secondary side coil 111b from being energized because a magnetic flux in the same direction as the magnetic field that generated the voltage) is generated. The secondary current I2 can be kept high. That is, if the secondary primary coil 111b generates a magnetic flux in the opposite direction to act on the secondary coil 112 after the ignition timing, the secondary primary coil 111b can superimpose the discharge energy on the secondary coil 112.

  The timing at which the power supply to the secondary primary coil 111b in the second direction is cut off is when a necessary and sufficient time for maintaining the secondary current I2 at a high current necessary for suitable combustion in the cylinder has elapsed. However, if the secondary primary coil 111b is continuously energized in the second direction for a longer time than that, the fuel efficiency is rather deteriorated. The desirable timing of energization / interruption of the sub-primary coil 111b is not fixed to a constant value, but changes variously depending on the structure of the internal combustion engine, the characteristics of the ignition coil, the operating condition, and the like. The setting value or setting information (calculation formula for obtaining the setting value, reference table, etc.) suitable for 1 may be stored in advance in the ignition control means 31 of the internal combustion engine drive control device 3.

  Further, when the second-direction energization to the sub-primary coil 111b is cut off, the counter electromotive force acts on the main primary coil 111a, so that in the reverse direction in which a current reverse to the normal primary current I1 is caused to flow. Since the voltage is applied between the collector and the emitter of the main switching element 12, there is a risk that the main switching element 12 may break down or the main switching element 12 may be deteriorated earlier. Therefore, the bypass line 13 is provided in parallel with the main switch element 12, and the rectifying means 14 becomes forward from the ground point GND side of the bypass line 13 toward the ignition coil 11 side (for example, the collector side of the main switch element 12). Is connected to the cathode of the main switching element 12 and the anode of the main switching element 12 is connected to the anode thereof.

  Next, a sub primary coil capable of switching between a forward magnetic flux generation state in which the first primary coil 111b can be energized in the first direction and a reverse magnetic flux generation state in which the second primary coil 111b can be energized in the second direction. A configuration example of the sub-primary coil magnetic flux generation state switching unit 5 which is the magnetic flux generation state switching means will be described. The sub primary coil magnetic flux generation state switching unit 5 includes a first sub switching element 51, a second sub switching element 52, a third sub switching element 53, and a fourth sub switching element 54.

  The first sub-switch element 51 functions as a first sub-switch means that switches the first end 111b1 side of the sub-primary coil 111b to the ground point GND so that the sub-primary coil 111b can be energized in the first direction. For example, the first sub-switch element 51 is composed of an insulated gate bipolar transistor for power control, and the collector C of the first sub-switch element 51 is on the second end 111b2 side of the sub-primary coil 111b. Is connected to the ground point GND side, and the ignition signal Si is input to the gate G of the first sub-switch element 51. Therefore, when the ignition signal Si is turned ON (for example, the signal level is H), the first sub switching element 51 is turned ON, and the second end 111b2 of the sub primary coil 111b is connected to the ground point GND.

  The second sub switching element 52 is capable of supplying power from the first power supply means (for example, the DC power supply 4) to the second end 111b2 side of the sub primary coil 111b so that the sub primary coil 111b can be energized in the first direction. Functioning as a second auxiliary switch means. For example, the second sub switching element 52 is configured by using a power MOS-FET having a high-speed switching characteristic, the drain D of the second sub switching element 52 is on the DC power source 4 side, and the source S of the second sub switching element 52 is. Is connected to the first end 111b1 side of the sub primary coil 111b, and the first direction energization instruction signal S1d from the ignition control means 31 is input to the gate G of the second sub switching element 52. Therefore, when the first direction energization instruction signal S1d is turned on (for example, the signal level is H), the second sub switch element 52 is turned on, and the DC power source 4 supplies the power supply voltage VB + to the first end 111b1 of the sub primary coil 111b. Will be applied.

  The third sub switch element 53 functions as a third sub switch unit that switches the second end 111b2 side of the sub primary coil 111b to the ground point GND so that the sub primary coil 111b can be energized in the second direction. For example, the third sub-switch element 53 is configured by using a power MOS-FET having a high-speed switching characteristic, and the drain D of the third sub-switch element 53 is located on the first end 111b1 side of the sub-primary coil 111b and the third sub-switch element 53. The source S of the switch element 53 is connected to the ground point GND side, and the second direction energization permission signal S2p from the ignition control means 31 is input to the gate G of the third sub switch element 53. Therefore, when the second direction energization permission signal S2p is turned on (for example, the signal level is H), the third sub switch element 53 is turned on, and the first end 111b1 of the sub primary coil 111b is connected to the ground point GND. It will be. A current detection resistor 62 is provided between the third sub switch element 53 and the ground point GND, and the sub primary current detection signal Di1s in the second direction is input to the internal combustion engine drive control device 3.

  The fourth sub switch element 54 is capable of supplying power from the second power supply means (for example, the DC power supply 4) to the first end 111b1 side of the sub primary coil 111b so that the sub primary coil 111b can be energized in the second direction. Functioning as a fourth sub-switching means. For example, the fourth sub switching element 54 is configured by using a power MOS-FET having a high-speed switching characteristic, the drain D of the fourth sub switching element 54 is on the DC power source 4 side, and the source S of the fourth sub switching element 54 is S. Is connected to the second end 111b2 side of the sub primary coil 111b, and the second direction energization instruction signal S2d from the ignition control means 31 is input to the gate G of the fourth sub switching element 54. Therefore, when the second direction energization instruction signal S2d is turned ON (for example, the signal level is H), the fourth sub switch element 54 is turned ON, and the DC power source 4 supplies the power supply voltage VB + to the second end 111b1 of the sub primary coil 111b. Will be applied. In order to increase the voltage applied to the sub-primary coil 111b, a higher-voltage DC power supply may be used instead of the VB + DC power supply 4 for the first power supply and the second power supply. Alternatively, a booster circuit 7 (shown by a chain double-dashed line in FIG. 1) may be provided to increase the voltage applied to the sub primary coil 111b.

  Here, a control example of the ignition control means 31 with respect to the sub primary coil magnetic flux generation state switching unit 5 having the above-described structure will be described based on FIGS. 2 to 5.

  FIG. 2 shows the main normal discharge control, which is a basic control in which the discharge energy is given to the secondary coil 112 by using only the main primary coil 111a during one combustion cycle.

  First, when the ignition signal Si is turned on at a predetermined timing during the combustion cycle, the main switch element 12 is turned on and the main primary current I1a flows. When the ignition signal Si is turned on, the first sub switching element 51 of the sub primary coil magnetic flux generation state switching unit 5 is also turned on, and the second end 111b2 side of the sub primary coil 111b is connected to the ground point GND. However, since the first-direction energization instruction signal S1d remains off, the sub-primary coil 111b is not energized in the first direction.

  The main primary current I1a increases until the saturation current is reached as time passes since the main primary coil 111a is energized, and energy is stored in the main primary coil 111a. Then, when the ignition signal Si is turned off at the ignition timing (when the signal level is changed from H to L), an electromotive force corresponding to the energy accumulated in the main primary coil 111a is generated on the secondary side, and the secondary current I2 is generated. As it flows, dielectric breakdown occurs between the electrodes of the spark plug 2 and discharge sparks are generated in the cylinder (capacity discharge). After that, the discharge (induction discharge) due to the release of the magnetic energy applied to the secondary coil 112 continues for about 0.5 to 2.5 ms, but the electromotive force generated in the secondary coil 112 gradually weakens and the secondary current I2 Since it also decays, it may not always be possible to obtain sufficient discharge spark to maintain suitable combustion in the cylinder.

  In the main normal discharge control described above, what is applied to the main primary coil 111a is constant at the power supply voltage VB + of the DC power supply 4, so the discharge energy applied from the main primary coil 111a to the secondary coil 112 is almost constant. is there. Therefore, when it is necessary to flow a high discharge current to the spark plug 2 for a longer time in order to maintain a stable combustion state, such as when the engine speed is low, the main primary coil 111a to the secondary coil 112 are connected. It is necessary to increase the discharge energy applied to the main primary coil 111a by prolonging the ON time of the ignition signal Si. However, if the ON time of the ignition signal Si is lengthened, the heat generation of the main switch element 12 that controls the energization of the main primary coil 111a becomes a problem, and the main switch element 12 malfunctions or the life of the switch element 12 is reduced. There is a risk of shrinking. Therefore, in the internal combustion engine ignition device 1 according to the present embodiment, by using the sub-primary coil 111b, the discharge energy applied to the secondary coil 112 at the ignition timing can be obtained without increasing the ON time of the ignition signal Si. It is possible to increase the length of the high current period.

  FIG. 3 shows the pre-ignition timing superimposition discharge control in which the sub primary coil magnetic flux generation state switching unit 5 is switched to the forward magnetic flux generation state to energize the main primary coil 111a and the sub primary coil 111b simultaneously. During the combustion cycle of 1, the energy stored in both the main primary coil 111a and the sub primary coil 111b is applied to the secondary coil 112 at once.

  First, at a predetermined timing in the combustion cycle, the ignition signal Si and the first direction energization instruction signal S1d are simultaneously turned ON, and the second direction energization permission signal S2p and the second direction energization instruction signal S2d are kept OFF. Then, the main switching element 12 and the first sub switching element 51 and the second sub switching element 52 of the sub primary coil magnetic flux generation state switching unit 5 are simultaneously turned on, and in addition to the main primary current I1a, the sub primary in the first direction is added. The current I1b1 flows. At this time, the current I1b1 in the first direction flows in the sub primary coil 111b, so that a forward magnetic flux in the same direction as the magnetic flux generated in the main primary coil 111a is generated in the sub primary coil 111b.

  The main primary current I1a and the sub primary current I1b increase until the saturation current is reached with the passage of time from the energization of the main primary coil 111a and the sub primary coil 111b, and the main primary coil 111a and the sub primary coil 111b receive energy. Is accumulated. When the ignition signal Si and the first direction energization instruction signal S1d are simultaneously turned off at the ignition timing, an electromotive force corresponding to the energy accumulated in the main primary coil 111a and the sub primary coil 111b is generated on the secondary side, When the next current I2 flows, dielectric breakdown occurs between the electrodes of the spark plug 2, causing a discharge spark in the cylinder.

  Here, the discharge energy given to the secondary coil 112 by simultaneously cutting off the main primary current I1a and the sub primary current I1b is given to the secondary coil 112 only from the main primary coil 111a by the above-mentioned main normal discharge control. Since the discharge energy is larger than the discharge energy (the shaded portion in the secondary current waveform in FIG. 3), the applied voltage that causes capacitive discharge is correspondingly increased, and a large secondary current I2 flows. Therefore, if the ignition control means 31 performs the superimposition discharge control before the ignition timing, the discharge energy applied to the secondary side is increased without increasing the ON time of the ignition signal Si, and a high discharge current is supplied for a longer time. It can be flowed to the spark plug 2.

  The pre-ignition timing superimposition discharge control is to superimpose the energy accumulated on the primary side by using the sub-primary coil 111b before the ignition timing at which discharge energy is generated on the secondary side by cutting off the current on the primary side. Every other time, it means a control for generating a discharge spark on the spark plug 2 by the discharge energy generated on the secondary side due to the current cutoff on the primary side.

  This pre-ignition timing superposed discharge control is not necessarily applicable only to increasing the discharge energy applied to the secondary side. For example, when the main primary coil 111a and the main switching element 12 are likely to be damaged by heat, by performing pre-ignition timing superimposed discharge control using the sub primary coil 111b, the main primary coil 111a and the main switching element 12 are controlled. The burden can be reduced.

  Specifically, the ignition control means 3 and the time reduction first direction energization instruction signal are controlled by the ignition control means 3 so that the ON time is appropriately shorter than the ON time of the ignition signal Si required in the main normal discharge control. By outputting S1d ', the time during which the primary primary current I1a and the secondary primary current I1b1 in the first direction flow through the primary primary coil 111a and the secondary primary coil 111b is shortened, and the primary primary coil 111a and the secondary primary coil 111b are respectively loaded. Reduce the energy stored. This makes it possible to cut off the main primary current I1a and the sub-primary current I1b1 in the first direction so that the discharge energy applied to the secondary side is about the same as the discharge energy applied to the secondary side by the main normal discharge control. Therefore, the spark plug 2 is not hindered from being discharged. Moreover, the heat generation amount of the main switch element 12 and the main primary coil 111a can be reduced by driving with the time shortened ignition signal Si '. Of course, even when it becomes necessary to apply more discharge energy to the secondary side, by appropriately adjusting the load ratio of the main primary coil 111a and the sub primary coil 111b, the main switch element 12 and the main primary coil 111a can be adjusted. There is an advantage that a necessary and sufficient high current period can be secured while suppressing generation of excessive heat.

  In the above-mentioned pre-ignition timing superimposition discharge control, by increasing the electromotive force generated on the secondary side due to the current cutoff on the primary side, a high current flows to the secondary side at once and capacitive discharge occurs, but after that, inductive discharge occurs. Since the period during which the high secondary current can be maintained does not dramatically increase, it cannot be said that the fuel consumption efficiency is necessarily good as the control for causing the high discharge current to flow through the ignition plug 2 for a longer time. Therefore, in the internal combustion engine ignition device 1 according to the present embodiment, by using the sub primary coil 111b, the high current period on the secondary side can be lengthened without lengthening the ON time of the ignition signal Si. It is possible.

  FIG. 4 shows that after the ignition timing by energization / interruption of the main primary coil 111a, the sub primary coil magnetic flux generation state switching unit 5 is switched to the reverse direction magnetic flux generation state to start energization of the sub primary coil 111b. This shows the discharge control, which is necessary to maintain the induced discharge from the sub-primary coil 111b after the ignition timing at which the secondary side is supplied with the discharge energy by the energization / interruption control to the primary side during one combustion cycle. This is a control that gives sufficient energy to the secondary side.

  First, when the ignition signal Si is turned on at a predetermined timing during the combustion cycle, the main switch element 12 is turned on and the main primary current I1a flows. When the ignition signal Si is turned on, the first sub switching element 51 of the sub primary coil magnetic flux generation state switching unit 5 is also turned on, and the second end 111b2 side of the sub primary coil 111b is connected to the ground point GND. However, since the first-direction energization instruction signal S1d remains off, the sub-primary coil 111b is not energized in the first direction.

  The main primary current I1a increases until the saturation current is reached as time passes since the main primary coil 111a is energized, and energy is stored in the main primary coil 111a. Then, when the ignition signal Si is turned off at the ignition timing (when the signal level is changed from H to L), an electromotive force corresponding to the energy accumulated in the main primary coil 111a is generated on the secondary side, and the secondary current I2 is generated. As it flows, dielectric breakdown occurs between the electrodes of the spark plug 2, and a discharge spark occurs in the cylinder (capacity discharge).

  After the capacity discharge occurs in the ignition plug 2 as described above and the discharge current starts to flow, the ignition control means 31 turns on the second-direction energization permission signal S2p (at the timing of transition from capacity discharge to induction discharge, for example). For example, the signal level is changed from L to H) and the second direction energization instruction signal S2d is turned ON. In the example shown in FIG. 4, the PWM control for changing the duty ratio of the second-direction energization instruction signal S2d is performed to adjust the power supplied to the sub primary coil 111b.

  Then, the secondary primary current I1b2 flowing in the secondary primary coil 111b gradually increases until it reaches the saturation current, and the magnetic flux in the opposite direction (in the same direction as the magnetic field generated in the secondary coil 112 after ignition timing). (Magnetic flux) also increases (indicated by shading in the sub-primary coil current waveform of FIG. 4). Therefore, the magnetic flux in the opposite direction generated in the sub-primary coil 111b acts on the secondary coil 112 so as to compensate for the decrease in the secondary current I2 due to the emission of electromagnetic energy from the secondary coil 112, and the secondary current I2 is high. The current is maintained as it is (indicated by shading in the secondary current waveform of FIG. 4), and the high current period suitable for in-cylinder combustion can be effectively lengthened.

  After that, when a high current maintaining period (high current period) necessary and sufficient for suitable in-cylinder combustion elapses, the ignition control means 31 turns off the second direction energization permission signal S2p and the second direction energization instruction signal S2d at that timing. To As a result, the reverse magnetic flux from the sub-primary coil 111b does not act on the secondary coil 112, so that a low secondary current I2 due to only electromagnetic energy emission from the secondary coil 112 flows thereafter, and the secondary current I2 eventually comes. Returns to zero.

  As described above, if the ignition control means 31 performs the superimposed discharge control after the ignition timing, the discharge energy applied to the secondary coil 112 is increased without increasing the ON time of the ignition signal Si, and the inter-electrode of the spark plug 2 is increased. The period during which the discharge current flowing through the battery can be maintained at a high current can be extended. In addition, since the reverse magnetic flux acting on the secondary coil 112 from the sub primary coil 111b is sufficient to generate and maintain a high current necessary and sufficient for maintaining the combustion in the cylinder appropriately, the sub primary coil 111b is required. The energy required to energize the vehicle can be kept low, which is effective in improving fuel efficiency. In addition, in the internal combustion engine ignition device 1 of the present embodiment, the ignition control means 31 can perform PWM control of the fourth switch element 54 of the sub primary coil magnetic flux generation state switching unit 5, so that after-ignition timing superimposed discharge control is performed. By appropriately increasing / decreasing the secondary primary current I1b2 flowing in the secondary primary coil 111b in the second direction, appropriate discharge energy without excess or deficiency can be given to the secondary side, and further improvement in fuel efficiency can be expected.

  Note that the post-ignition timing superimposed discharge control is to superimpose energy to be given to the secondary side by using the sub-primary coil 111b after the ignition timing at which discharge energy is generated on the secondary side by interrupting the current on the primary side. This means a control for maintaining the discharge generated in the spark plug 2 for a necessary and sufficient period.

  Further, the timing at which the secondary primary current I1b2 in the second direction starts to flow to the secondary primary coil 111b may be after the ignition timing and is not particularly limited. For example, it may be performed at the same time as the current cutoff to the main primary coil 111a, or the secondary primary current I1b2 may be made to flow after a predetermined time has elapsed from the current cutoff at the primary side, or the secondary current may be made to flow to the secondary side. When the next current I2 reaches a predetermined judgment value (for example, the value of the secondary current considered to be high below which the discharge current flowing through the spark plug 2 is below a high current value capable of maintaining discharge spark formation suitable for in-cylinder combustion). Alternatively, the sub primary current I1b2 may be passed.

  The above-mentioned pre-ignition timing superposition discharge control and post-ignition timing superposition discharge control superimpose discharge energy on the secondary side by using the same secondary primary coil 111b, but the control is performed before and after ignition timing. Since they are separated, it is possible to perform both controls during one combustion cycle.

  FIG. 5 shows a case where the post-ignition superimposition discharge control is performed and then the post-ignition superimposition discharge control is performed, and the main primary coil 111a and the sub-primary coil 111b both store the same during one combustion cycle. This is a control in which after the energy is applied to the secondary coil 112 all at once, the energy necessary and sufficient for maintaining the induced discharge is further applied to the secondary side from the sub primary coil 111b.

  That is, by simultaneously cutting off the main primary current I1a and the sub primary current I1b, the discharge energy given to the secondary side is the amount of the addition of the sub primary coil 111b (in the sub primary coil waveform of FIG. (Shown), the applied voltage that causes capacitive discharge on the secondary side is correspondingly increased (indicated by thin shading in the secondary current waveform of FIG. 5), and further, the secondary primary coil 111b is moved in the second direction. The secondary current I1b2 flows (the shaded portion in the sub-primary coil waveform in FIG. 5) acts on the secondary coil 112, and the secondary current I2 is maintained as a high current (see FIG. 5). In the secondary current waveform, it is indicated by dark shading).

  As described above, if the pre-ignition timing superposed discharge control and the post-ignition timing superposed discharge control are performed during one combustion cycle, it is possible to give a larger discharge energy to the secondary side than when the respective controls are performed alone. Therefore, good and stable in-cylinder combustion can be realized even under severe operating conditions.

  According to the internal combustion engine ignition device 1 according to the first embodiment described above, the main normal discharge control, the pre-ignition timing superposed discharge control, and the post-ignition timing superposed discharge are optimized so as to be optimal according to the operating condition of the internal combustion engine. Since control and pre-ignition timing superposition discharge control + post-ignition timing superposition discharge control can be used properly, power consumption for ignition can be optimized and a high fuel efficiency improvement effect can be expected.

  In addition, the ignition coil 11 used in the ignition device 1 for an internal combustion engine includes the main primary coil 111a and the sub primary coil 111b, but can be configured to have the same size as an existing ignition coil. Therefore, it is not necessary to use a plurality of coils or a booster circuit to increase the discharge energy applied to the secondary side, and the ignition coil 11 having the same size as that of the existing ignition coil is sufficient. Cost increase can be suppressed.

  The internal combustion engine ignition device 1 according to the first embodiment has a function for controlling the energization direction and energization / interruption of the sub-primary coil 111b, that is, the first to fourth sub-switch elements 51 to 54. Although the magnetic flux generation state switching unit 5 is unitized, the unit is not limited to this. For example, the first sub switch element 51 of the sub primary coil magnetic flux generation state switching unit 5 is turned on / off in synchronization with the main switch element 12 by the ignition signal Si, so that the signal path of the ignition signal Si is simple. Therefore, it is conceivable to dispose the main switch element 12 and the first sub switch element 51 close to each other.

  Therefore, in the internal combustion engine ignition device 1'according to the second embodiment shown in FIG. 6, the first auxiliary switch element 51 is housed in the case 15 of the ignition coil unit 10 '. The gate G which is the control terminal of the main switching element 12 and the gate G which is the control terminal of the first sub switching element 51 are connected to the fourth connection terminal 152d, and the internal combustion engine drive control device 3 is connected via the fourth connection terminal 152d. Ignition signal from is input. In this way, the signal path of the ignition signal Si can be simplified. The main switch element 12 and the first sub switch element 51 use discrete components having high heat resistance and noise resistance, so that stable operation can be achieved even if they are integrally sealed with the ignition coil 11. The sub primary coil magnetic flux generation state switching unit 5'is unitized by housing the second sub switching element 52, the third sub switching element 53 and the fourth sub switching element 54 in one case.

  Also in the internal combustion engine ignition device 1 ′ according to the second embodiment, the ignition control device 31 controls the ignition signal Si, the first direction energization instruction signal S1d, the second direction energization permission signal S2p, and the second direction energization instruction signal S2d. Is output to the ignition coil unit 10 or the sub-primary coil magnetic flux generation state switching unit 5'at an appropriate timing, so that the main normal discharge control similar to that of the internal combustion engine ignition device 1 according to the first embodiment and the pre-ignition timing superimposition discharge are performed. Control, superposed discharge control after ignition timing, superposed discharge control before ignition timing + superposed discharge control after ignition timing can be performed.

  In the internal combustion engine ignition devices 1 and 1'according to the first and second embodiments described above, both the main switch element 12 and the first sub switch element 51 are controlled by the ignition signal Si. The 12 and the first sub-switch element 51 may be ON / OFF controlled by different signals.

  The internal combustion engine ignition device 1 ″ of the third embodiment shown in FIG. 7 generates the main ignition signal Sia and the auxiliary ignition signal Sib by the ignition control means 31 ″ of the internal combustion engine drive control device 3 ″, and uses the main ignition signal Sia. The main switch element 12 is ON / OFF controlled, and the first sub switch element 51 of the sub primary coil magnetic flux generation state switching unit 5 is ON / OFF controlled by the sub ignition signal Sib. It becomes possible to flow the sub-primary current I1b1 in the first direction through the sub-primary coil 111b without flowing the current I1a.

  8 shows the sub-normal discharge control performed by the internal combustion engine ignition device 1 ″ of the third embodiment configured as described above. The sub-normal discharge control uses only the sub-primary coil 111b during one combustion cycle. Control for giving discharge energy to the secondary side by means of, for example, it is effective when the main primary coil 111a and the main switch element 12 for performing main normal discharge control are damaged by heat generation.

  First, when the sub ignition signal Sib and the first direction energization instruction signal S1p are turned on at a predetermined timing in the combustion cycle, the first sub switching element 51 and the second sub switching element 52 are turned on at the same time, and the first direction The secondary primary current I1b1 flows. Note that the sub ignition signal Sib cannot control the flow of the sub primary current I1b by this signal alone, but connects the second end 111b2 of the sub primary coil 111b to the ground point GND side and supplies power from the first end 111b1. Since it is possible to perform the above, it corresponds to the first direction energization permission signal S1p.

  With the passage of time from the energization of the sub primary coil 111b, the sub primary current I1b1 in the first direction increases until it reaches the saturation current, and energy is accumulated in the sub primary coil 111b. Then, when the ignition signal Si is turned off at the ignition timing (when the signal level is changed from H to L), an electromotive force corresponding to the energy accumulated in the sub primary coil 111b is generated on the secondary side, and the secondary current I2 flows. At the same time, a dielectric breakdown occurs between the electrodes of the spark plug 2 to generate a discharge spark in the cylinder.

  As described above, if the sub-normal discharge control is performed, the normal primary energy is applied to the secondary side only by the sub-primary coil 111a without using the main primary coil 111a, and the normal discharge is generated in the ignition plug 2. Is possible. Further, in the internal combustion engine ignition device 1 ″ according to the third embodiment, the main primary coil 111a and the sub primary coil 111b can be selectively used as coils for accumulating energy to be given to the secondary side. It is possible to avoid excessive load on only the primary coil 111a, and to effectively avoid accidental failure of the ignition coil 11. Also, due to some factors, the main primary coil 111a in the ignition coil unit 10, the main switching element 12 or Even if the main primary discharge control or the secondary normal discharge control is disabled due to a failure of any of the secondary primary coils 111b, the primary normal discharge control or the secondary normal discharge control can be performed by the primary coil that functions normally. Therefore, the discharge of the ignition coil 2 can be ensured, and the worst situation in which the cylinder concerned cannot be ignited can be avoided. A.

  Further, in the internal combustion engine ignition device 1 ″ according to the third embodiment, since the main ignition signal Sia and the sub ignition signal Sib can be independently controlled, the timing of starting energization of the sub primary coil 111b by the sub ignition signal Sib is mainly set. The energy stored in the sub primary coil 111b can be adjusted by controlling the ignition control means 31 so as to be delayed from the timing at which the main primary coil 111a is energized by the ignition signal Sia, for example, the ON time of the main ignition signal Sia. Then, when the energy stored in the main primary coil 111a is slightly insufficient, the ON time of the main ignition signal Sia is not lengthened, and the ON time is set to such an extent that the shortage of energy is supplemented by the sub primary coil 111b. By outputting the ignition signal Sib (and the first direction energization instruction signal S1d), necessary and sufficient energy can be obtained. Stable ignition control can be realized by being accumulated in the main primary coil 111a and the sub primary coil 111b. Moreover, since it is not necessary to lengthen the ON time of the main ignition signal Sia, heat generation of the main primary coil 111a and the main switch element 12 is prevented. It is also useful in that it can be reduced.

  When the DC power source 4 is used as the DC power source for supplying power to the main primary coil 111a and the sub primary coil 111b, as in the internal combustion engine ignition device 1 ", the main primary coil 111a and the sub primary coil 111b are connected to each other. By making the number of turns the same, the discharge energy given to the secondary side by the main normal discharge control and the discharge energy given to the secondary side by the sub normal discharge control can be made substantially equal. When the number of turns of the sub-primary coil 111b is smaller than the number of turns, a power source having a voltage higher than that of the DC power source 4 or a booster circuit is used as the first power feeding means for supplying power to the sub-primary coil 111b. Even when the voltage applied to the sub primary coil 111b is increased, the discharge energy equivalent to that of the main normal discharge control can be obtained by the sub normal discharge control. It is desirable to adjust as given to the secondary side.

  Each of the internal combustion engine ignition devices 1, 1 ′ and 1 ″ according to the first to third embodiments described above shows only one cylinder, but in the case of an internal combustion engine including a plurality of cylinders, The sub-primary coil magnetic flux generation state switching unit 5 may be provided, or all the first to fourth sub-switch elements 51 to 54 corresponding to each cylinder may be integrated into a single case. The ignition coil unit 10 may be connected.

  Although some embodiments of the internal combustion engine ignition device according to the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these embodiments and is described in the claims. As long as the configuration is not changed, known equivalent technical means may be diverted.

DESCRIPTION OF SYMBOLS 1 Ignition device for internal combustion engine 10 Ignition coil unit 11 Ignition coil 111a Main primary coil 111b Sub primary coil 112 Secondary coil 113 Center core 12 Main switch element 15 Case 2 Spark plug 3 Internal combustion engine drive control device 31 Ignition control means 4 DC power supply 5 Sub-Primary Coil Magnetic Flux Generation State Switching Unit 51 First Sub-Switch Element 52 Second Sub-Switch Element 53 Third Sub-Switch Element 54 Fourth Sub-Switch Element

Claims (1)

A main primary coil in which the forward magnetic flux is increased by energization and the forward magnetic flux is reduced by cutting off the current,
A sub- primary coil which is provided separately from the main primary coil and generates a magnetic flux in the same forward direction as the main primary coil when energized,
A secondary coil, one end side of which is connected to an ignition plug, and a magnetic flux generated in the main primary coil and the sub primary coil acts to generate discharge energy,
An ignition coil having
A main switch means for switching between energization and interruption from a battery to the main primary coil,
Auxiliary switch means for switching between energization / interruption from the battery to the sub primary coil,
Ignition control means for controlling the main switch means and the sub switch means to generate a discharge spark at an ignition plug at a predetermined timing of a combustion cycle,
Equipped with
The ignition control means,
It is possible to perform normal discharge control for generating discharge energy in the secondary coil by controlling the energization / interruption of the main primary coil,
An ignition device for an internal combustion engine capable of performing pre-ignition timing superimposition discharge control for simultaneously controlling energization / interruption of the main primary coil and the sub-first ignition coil.

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