JP5082530B2 - Engine ignition control device - Google Patents

Description

  The present invention relates to an apparatus for controlling ignition of an engine.

For example, the engine ignition device described in Patent Document 1 applies a high voltage in the form of a short rectangular wave from a pulse power supply to an electrode arranged in a cylinder head. First, streamer discharge (corona discharge) due to low-temperature plasma is generated on the electrode to which a short pulse high voltage is applied, and then arc discharge due to thermal plasma is generated. The fuel is ignited by such a discharge form. According to such an engine ignition device, it is possible to increase the ignition energy, increase the ignition region, and promote the propagation of flame to the entire combustion chamber as compared with a device using a normal spark plug. Increased capacity.
JP 2000-110697 A

  However, the conventional engine ignition device using the streamer discharge (corona discharge) by the low-temperature plasma described above has a problem that a large amount of current flows from a bridging part at the time of arc discharge, resulting in high power consumption due to the discharge. It was.

  The present invention has been made paying attention to such conventional problems, and an object of the present invention is to provide an engine ignition device that does not require large power consumption.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

The present invention includes a positive electrode (11a) and a negative electrode (11b) arranged in a combustion chamber (21) of an engine (20), and generates a corona discharge due to low-temperature plasma when a short pulse high voltage is applied, An engine ignition control device for controlling ignition of the engine (20) by discharge means (11) that generates arc discharge by thermal plasma when the positive electrode (11a) and the negative electrode (11b) are electrically short-circuited thereafter. Is an engine that can control the intake air amount by controlling the opening and closing of the intake valve according to the load, and controls the engine state detecting means (step S22) for detecting the engine state at the ignition timing and the opening and closing of the intake valve. when reducing the effective intake stroke Te, the so discharged by the discharge means (11) to maintain a corona discharge without transition to arc discharge, detected as the engine load conditions The lower voltage applied short pulse high voltage applied to the discharge means (11) is high, the discharge control means applying time is short (step S23), and characterized by having a.

According to the present invention, according to the engine condition, since to control between time of the application voltage and application of a short pulse high voltage applied to the discharging means, a corona discharge discharge by the discharge means does not transition to an arc discharge It can now be maintained and does not require significant power consumption.

Hereinafter, the best mode for carrying out the present invention will be described in more detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a first embodiment of an engine ignition device according to the present invention.

  The engine ignition device 10 includes a discharge electrode 11 and a short pulse high voltage generator 12.

  Discharge electrode 11 is arranged to open to the ceiling of combustion chamber 21 of engine 20. The engine configuration is the same as a normal one. That is, the combustion chamber 21 is formed by the cylinder head 22, the cylinder block 23, and the piston 24. The cylinder head 22 is formed with an intake port 22a and an exhaust port 22b. A fuel injector 25 is provided in the intake port 22a. The intake port 22a is opened and closed by an intake valve 51 that responds to engine rotation. The exhaust port 22b is opened and closed by an exhaust valve 61 that responds to engine rotation.

  When a short pulse high voltage is applied, the discharge electrode 11 is a discharge means that generates corona discharge by low-temperature plasma and then generates arc discharge by thermal plasma. The discharge electrode 11 has a center electrode 11a having a protrusion and a side electrode 11b formed in a cylindrical shape around the center electrode 11a, and both electrodes are insulated by an insulator 11c. In this embodiment, the center electrode 11a is a positive electrode and the side electrode 11b is a negative electrode. However, the center electrode 11a may be a negative electrode and the side electrode 11b may be a positive electrode.

  The short pulse high voltage generator 12 includes a pulse generator 12 a and a high voltage generator 12 b, and applies a short pulse high voltage to the discharge electrode 11. The application voltage, application time, and application (ignition) timing of the short pulse high voltage are controlled by the controller 70. The controller 70 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 70 may be composed of a plurality of microcomputers.

  FIG. 2 is an enlarged view of the vicinity of the tip of the discharge electrode, and particularly shows a state during corona discharge. 2A is a longitudinal sectional view, and FIG. 2B is a transverse sectional view.

  As described above, the side electrode 11 b is formed in a cylindrical shape around the center electrode 11 a of the discharge electrode 11. When the discharge electrode 11 undergoes corona discharge, a multi-branch streamer S is generated over a wide range between the center electrode 11a and the side electrode 11b. As a result, volumetric ignition occurs.

  Here, the discharge mode when a voltage is applied to the discharge electrode 11 will be described.

  When a high voltage is applied to the discharge electrode 11, electrons are released from the negative electrode (the side electrode 11b in this embodiment) and accelerated toward the positive electrode (the center electrode 11a in this embodiment). On the way, the electrons collide with the atmospheric gas, ionize the atmospheric gas, and further generate free electrons (this phenomenon is called “electron avalanche”). Free electrons immediately go to the positive electrode, but large positive ions are left behind.

  Further, an avalanche of electrons is induced by the potential difference generated between the positive ion group and the negative electrode, and a plasma (low temperature plasma) called positive streamer mixed with positive ions and electrons is generated. The discharge form in which the streamer is generated is called corona discharge.

  As shown in FIG. 2, a plurality of streamers are generated at the positive electrode (center electrode 11a). When any of the streamers reaches the negative electrode (side electrode 11b) and the positive and negative electrodes are electrically short-circuited, a short circuit occurs. A large current flows through the formed part, and a single arc is generated. The form of discharge in a state where an arc is generated is called arc discharge.

  FIG. 3 is a diagram for explaining power consumption by corona discharge and arc discharge.

  As described above, corona discharge occurs in a transient state from the start of voltage application to transition to arc discharge. Since corona discharge accelerates only light electrons without accelerating protons with large mass, it consumes less current than arc discharge. For this reason, as shown in FIG. 3, the corona discharge can apply a higher voltage (about 30 to 100 kV) than the arc discharge, and the combustion reaction can be promoted by the electrons accelerated by the high energy of the corona discharge. Further, in the corona discharge, as shown in FIG. 2, a multi-branch streamer is generated in a wide range between the electrodes, so that there are a plurality of parts that ignite, and as a result, the volume of the part where the ignition occurs increases. The generated flame is ejected into the combustion chamber 21, and combustion in the combustion chamber 21 starts from the vicinity of the opening of the discharge electrode 11. Such volumetric ignition makes it possible to realize combustion with high isovolume.

  On the other hand, when transitioning to arc discharge, a large current flows through the part short-circuited by the arc, and the voltage drops rapidly as shown in FIG. As a result, power consumption increases rapidly. In addition, since arc discharge is performed at a limited part of the electrode, the mixture is ignited locally, and the distance (flame propagation distance) required for the flame to spread throughout the combustion chamber is increased.

  For this reason, a sufficient combustion rate is possible under operating conditions where the in-cylinder atmosphere is unfavorable for combustion of the air-fuel mixture, such as when the engine is operated at a low load and at a low speed, or when the air-fuel ratio is leaner than the stoichiometric air-fuel ratio. Cannot be obtained. In order to increase the burning rate, the input energy must be increased.

  Therefore, in the present invention, until ignition occurs, the transition from corona discharge to arc discharge is prevented and the electron temperature of the air-fuel mixture is increased by the streamer, thereby achieving high-volume combustion with low power consumption.

  FIG. 4 is a flowchart for explaining the operation of the first embodiment of the engine ignition device according to the present invention. Hereinafter, the specific control logic of the controller will be described with reference to the flowchart of FIG.

  In step S1, the controller 70 detects the engine speed NE and the accelerator pedal depression amount APO.

  In step S2, the controller 70 obtains the target torque TTC based on the accelerator pedal depression amount APO. Specifically, for example, it is obtained based on a characteristic map shown in FIG. This map is set in advance through experiments.

  In step S3, the controller 70 sets an optimal ignition timing ADV for each operating condition. Specifically, for example, it is set with reference to a characteristic map that is allocated in advance to the engine speed NE and the target torque TTC and stored in the ROM through experiments. If the load is the same (target torque TTC), the ignition timing is set to advance as the engine speed NE increases.

  In step S <b> 4, the controller 70 sets the application voltage Vd and the application time Td of the short pulse high voltage applied to the discharge electrode 11. Specifically, for example, it is set by referring to a characteristic map that is allocated to the engine speed NE and the target torque TTC and stored in the ROM through experiments in advance. Note that one of the applied voltage Vd and the applied time Td may be a fixed value, and only the other may be controlled. Although different depending on the operation state, for example, the applied voltage Vd is set to about 30 to 100 kV, and the application time Td is set to about 30 to 200 nanoseconds.

  In step S5, the controller 70 applies the applied voltage Vd and the applied time Td to the discharge electrode 11 at the set ignition timing ADV. Then, corona discharge occurs between the electrodes.

  According to this embodiment, since the application state is controlled according to the operating conditions, ignition by corona discharge can always be realized, and the combustion reaction can be promoted by high-energy accelerated electrons. In addition, the volumetric ignition due to streamer formation improves thermal efficiency in a wide operating range. In particular, it is possible to reliably suppress an arc discharge transition in a high voltage application state and to reduce energy consumption.

(Second Embodiment)
FIG. 6 is a flowchart for explaining the operation of the second embodiment of the engine ignition device according to the present invention.

  In the following description, the same reference numerals are given to portions that perform the same functions as those in the above-described embodiment, and overlapping descriptions are omitted as appropriate.

  Steps S1 to S3 are the same as in the first embodiment.

  In step S21, the controller 70 sets the target fuel-air ratio TFBYA. Specifically, for example, it is set with reference to a characteristic map that is allocated in advance to the engine speed NE and the target torque TTC and stored in the ROM through experiments.

  In step S22, the controller 70 detects the in-cylinder gas state (for example, the in-cylinder pressure) at the ignition timing ADV. Specifically, for example, it may be estimated (indirectly detected) with reference to a characteristic map that is assigned to the ignition timing ADV, the intake air amount QM, and the engine speed NE and stored in the ROM through experiments in advance. Further, a gas sensor (in-cylinder pressure) may be directly detected by providing a pressure sensor in the cylinder.

  In step S23, the controller 70 sets the application voltage Vd of the short pulse high voltage applied to the discharge electrode 11 and the application time Td based on the gas state (cylinder pressure) in the cylinder. Specifically, for example, the applied voltage Vd is set based on the characteristic map shown in FIG. 7A stored in advance in the ROM, and the application time Td is set based on the characteristic map shown in FIG. 7B. This map is set in advance through experiments.

  In step S22, the controller 70 detects the in-cylinder pressure as the in-cylinder gas state, but may also detect the in-cylinder gas density or the mixture concentration. The detection may be detected directly by a sensor or indirectly by calculation based on other detection values. In step S23, the application voltage Vd of the short pulse high voltage applied to the discharge electrode 11 and the application time Td may be set based on the characteristic maps shown in FIGS. Further, the applied voltage Vd and the applied time Td may be finally set in consideration of the in-cylinder pressure, the in-cylinder gas density, and the gas mixture concentration. Further, humidity may be taken into consideration. Alternatively, only one of the applied voltage Vd and the application time Td may be set as a fixed value, and the other may be controlled.

  The inventors of the present invention have conducted intensive research, and when the interelectrode distance and the pulse voltage application time are constant, the required voltage required for forming a streamer by corona discharge increases with an increase in in-cylinder pressure. It has been found that the application time from the increase to the transition from the corona discharge to the arc discharge becomes longer as the in-cylinder pressure increases.

Therefore, in the present embodiment, the applied voltage is set higher as the in-cylinder pressure is higher. In this way, a stable streamer can always be formed between the electrodes in a wide pressure range. In other words, the streamer can be stably formed even when the in-cylinder pressure becomes high, and the arc discharge due to excessive voltage can be suppressed even when the in-cylinder pressure becomes low. Since it was made longer, the streamer's existence time due to corona discharge at the time of ignition could be made longer, and the combustion stability was increased.

  In addition, the present inventors have conducted intensive research, and when the interelectrode distance and the pulse voltage application time are constant, the required voltage required for forming a streamer by corona discharge is a function of the in-cylinder gas density. It has been found that the required voltage required for corona discharge tends to increase as the cylinder gas density increases.

  Therefore, in this embodiment, the applied voltage is set higher as the in-cylinder gas density is higher. In this way, a stable streamer can always be formed between the electrodes in a wide range. In addition, by taking into account the in-cylinder gas density, the accuracy can be made higher than when the voltage value is determined only by pressure.

  Similarly, when the interelectrode distance and pulse voltage application voltage are constant, the application time from the corona discharge with streamer formation to the arc discharge can be increased as the in-cylinder gas density increases. I found out.

  Therefore, in this embodiment, the application time is lengthened as the in-cylinder gas density is higher. By doing in this way, the existence time of the streamer by the corona discharge at the time of ignition can be further prolonged, and the combustion stability is increased. In addition, the accuracy can be made higher than when the application time is determined only by pressure.

  Further, when the distance between the electrodes and the pulse voltage application time are constant, the inventors of the present invention have a smaller required voltage required for streamer formation by corona discharge as the in-cylinder gas density is the same and the mixture concentration is lower. We found that there was a tendency to increase.

  Therefore, in the present embodiment, the applied voltage is increased as the air-fuel mixture concentration is lower (the air-fuel ratio is higher). By doing so, the maximum voltage value immediately before the transition to the arc can be applied to the electrode, the combustion reaction is promoted, and the isovolume during combustion can be improved.

  Similarly, when the inter-electrode distance and the pulse voltage application time are constant, the application time until the transition from corona discharge with streamer formation to arc discharge is reduced as the in-cylinder gas density is the same and the gas mixture concentration is dilute. It was found that it can be set a little longer.

  Therefore, in this embodiment, the application time is made longer as the air-fuel mixture concentration is lower (the air-fuel ratio is higher). In this way, the streamer existing time by corona discharge at the time of ignition can be further increased, and the combustion stability is increased.

(Third embodiment)
FIG. 10 is a diagram showing a setting example of the applied voltage Vd and the applied time Td in the third embodiment of the engine ignition device according to the present invention.

  This embodiment is applied when adjusting a load by throttling control. In this case, as shown in FIG. 10A, the application time Td is constant, and the application voltage Vd assigned to each load and stored in the ROM is set. The applied voltage Vd is set smaller as the load is smaller. Note that values not stored in the ROM may be linearly interpolated based on previous and subsequent values.

  Further, as shown in FIG. 10B, the applied voltage Vd may be made constant, and the applied time Td may be set smaller as the load is smaller.

  Further, the applied voltage Vd and the applied time Td may be simultaneously controlled in consideration of the characteristics shown in FIGS. 7 to 9 in consideration of the in-cylinder pressure, the in-cylinder gas density, and the gas mixture concentration.

  If the load is the same, the higher the engine speed, the lower the applied voltage and the shorter the application time.

  During engine low-load operation, arc discharge due to excessive voltage may occur. Therefore, in this embodiment, the applied voltage Vd is set to be smaller as the load is lower. By doing so, corona discharge can be realized with certainty. Further, since the application time Td is set to be smaller as the load is lower, the arc discharge due to the excessive application time can be suppressed, and corona discharge can be realized with certainty.

  If the load is the same, the ignition timing is set to advance as the engine speed increases. Also, the higher the engine speed, the lower the applied voltage and the shorter the application time.

  The faster the engine speed, the lower the in-cylinder pressure (or density) at the time of ignition.The faster the engine speed, the lower the applied voltage and the shorter the application time, so that arc discharge due to excess voltage is reduced. Therefore, corona discharge can be realized with certainty.

(Fourth embodiment)
FIG. 11 is a diagram showing a configuration of a variable valve mechanism for an engine to which a fourth embodiment of the engine ignition device according to the present invention is applied.

  In the present embodiment, the opening and closing of the intake valve 51 is controlled according to the required load. In order to control the opening / closing of the intake valve 51 according to the required load, for example, a variable valve mechanism disclosed in Japanese Patent Application Laid-Open No. 11-107725 may be used. Here, the variable valve mechanism will be briefly described with reference to FIG.

  The variable valve mechanism 200 includes a cam shaft 210, a link arm 220, a valve lift control shaft 230, a rocker arm 240, a link member 250, and a swing cam 260. The valve 51 is opened and closed.

  The camshaft 210 is rotatably supported on the cylinder head along the engine longitudinal direction. One end of the camshaft 210 is inserted into the cam sprocket 270. The cam sprocket 270 rotates with torque transmitted from the crankshaft of the engine. The camshaft 210 rotates with the cam sprocket 270. The camshaft 210 rotates relative to the cam sprocket 270 by hydraulic pressure, and can change the phase with respect to the cam sprocket 270. With such a structure, the rotational phase of the camshaft 210 relative to the crankshaft can be changed. A cam 211 is fixed to the camshaft 210. The cam 211 rotates integrally with the cam shaft 210. A pair of swing cams 260 connected by pipes are inserted through the camshaft 210. The swing cam 260 swings about the camshaft 210 as a rotation center and opens and closes the intake valve 51.

  The link arm 220 is supported through the cam 211.

  The valve lift control shaft 230 is disposed in parallel with the camshaft 210. A cam 231 is integrally formed on the valve lift control shaft 230. The valve lift control shaft 230 is controlled by an actuator 280 so as to rotate within a predetermined rotation angle range.

  The rocker arm 240 is supported through the cam 231 and is connected to the link arm 220.

  The link member 250 is connected to the rocker arm 240.

  The swing cam 260 is inserted through the cam shaft 210 and can swing about the cam shaft 210. The swing cam 260 is connected to the link member 250. The swing cam 260 moves up and down to push down the intake valve 51 via the tappet 53.

  Next, the operation of the variable valve mechanism 200 will be described with reference to FIG.

  12 (A-1) and 12 (A-2) are views showing a state when the lift amount of the intake valve 51 is maximized. FIG. 12A-1 shows a state where the intake valve 51 is closed and the swing direction of the swing cam 260 is reversed. That is, at this time, the cam nose 260b is at the highest position. FIG. 12 (A-2) shows a state where the intake valve 51 is in an open state and the swing direction of the swing cam 260 is reversed. That is, at this time, the cam nose 260b is at the lowest position.

  12 (B-1) and 12 (B-2) are views showing a state when the lift amount of the intake valve 51 is minimized. FIG. 12 (B-1) shows a state where the cam nose 260b is at the highest position and the swing direction of the swing cam 260 is reversed. FIG. 12B-2 shows a state where the cam nose 260b is at the lowest position and the swing direction of the swing cam 260 is reversed. In the present embodiment, the maximum lift amount of the intake valve 51 is zero. Therefore, in FIGS. 12B-1 and B-2, the intake valve 51 is always closed regardless of the operation of the swing cam 260.

  In order to increase the lift amount of the intake valve 51, as shown in FIGS. 12A-1 and 12A-2, the valve lift control shaft 230 is rotated to lower the position of the cam 231 and the shaft center P1 is pivoted. Set below the heart P2. As a result, the entire rocker arm 240 moves downward.

  When the camshaft 210 is rotationally driven in this state, the driving force is transmitted from the link arm 220 → the rocker arm 240 → the link member 250 → the swing cam 260.

  As shown in FIG. 12A-1, when the cam 211 is on the left side of the camshaft 210, the base circle portion 260a of the swing cam 260 is in contact with the tappet 53. At this time, the intake valve 51 is closed. To do.

  As shown in FIG. 12A-2, when the cam 211 is on the right side of the camshaft 210, the cam nose 260b of the swing cam 260 is in contact with the tappet 53, and at this time, the intake valve 51 is opened.

  In order to reduce the lift amount of the intake valve 51, as shown in FIGS. 12 (B-1) and 12 (B-2), the valve lift control shaft 230 is rotated to raise the position of the cam 231 and the shaft center P1 is pivoted. Set to the upper right of the center P2. As a result, the entire rocker arm 240 moves upward.

  When the camshaft 210 is rotationally driven in this state, the driving force is transmitted from the link arm 220 → the rocker arm 240 → the link member 250 → the swing cam 260.

  As shown in FIG. 12B-1, when the cam 211 is on the left side of the camshaft 210, the base circle portion 260a of the swing cam 260 is in contact with the tappet 53. At this time, the intake valve 51 is closed. To do.

  As shown in FIG. 12B-2, even when the cam 211 is on the right side of the camshaft 210, the base circle portion 260a of the swing cam 260 is in contact with the tappet 53. At this time, the intake valve 51 Closes.

  As described above, when the valve lift control shaft 230 is rotated to raise the position of the cam 231 and the shaft center P1 is set to the upper right of the shaft center P2, the camshaft 210 rotates to swing the swing cam. Even if it moves, the intake valve 51 is always closed.

  FIG. 13 is a diagram showing the lift amount and opening / closing timing of the intake valve 51 by the variable valve mechanism 200. A solid line shows the lift amount and opening / closing timing of the intake valve 51 when the valve lift control shaft 230 is rotated. The broken line is a diagram showing the opening / closing timing of the intake valve 51 when the phase of the camshaft 210 with respect to the cam sprocket 270 is changed.

  According to the structure of the variable valve mechanism 200 described above, the lift amount and operating angle of the intake valve 51 can be continuously changed. Thus, by changing the angle of the valve lift control shaft 230 and the phase of the camshaft 210 with respect to the cam sprocket 270, the lift amount and the operating angle of the intake valve 51 can be changed continuously and freely.

  In this embodiment, the smaller the load, the smaller the intake valve operating angle, the earlier the closing timing (IVC), the suction is stopped in the middle of the intake stroke, and the intake is expanded / compressed around the bottom dead center. . In this way, the engine is operated in a mirror cycle that changes the actually effective suction stroke, reduces the cylinder volume at the start of compression, and reduces pump loss.

  And as shown in FIG. 14, the application time Td of the short pulse high voltage applied to an electrode is set shorter and the applied voltage Vd is set higher as the load is smaller.

  When the mechanical compression ratio is fixed and the operating angle of the intake valve is reduced and the effective intake stroke is reduced as the load is reduced, the actual compression ratio is reduced as the load is reduced, and the in-cylinder pressure and temperature are reduced. It is disadvantageous for ignition and combustion.

  Therefore, in the present embodiment, the applied voltage is increased as the load is reduced. By doing so, the energy of the accelerated electrons is increased (the energy is collected over time), and the combustion stability is improved. On the other hand, the shorter the load, the shorter the application time of the short pulse high voltage applied to the electrode. By doing in this way, the arc discharge by excessive application time can be suppressed and corona discharge can be implement | achieved reliably.

(Fifth embodiment)
FIG. 15 is a diagram showing an example of a control map of the fifth embodiment of the engine ignition apparatus according to the present invention.

  In this embodiment, the load is adjusted by lean combustion or dilution combustion by EGR (Exhaust Gas Recirculation). In this way, the specific heat ratio κ is improved, and the thermal efficiency is improved by reducing the cooling loss. In this case, since the mixing ratio concentration decreases as the load decreases, it is desirable to set the applied voltage high as shown in FIG. Therefore, as shown in FIG. 15A, the applied voltage Vd is increased as the load is reduced.

  Further, as shown in FIG. 15B, as the load decreases, the application time Td of the short pulse high voltage applied to the electrodes may be shortened and the applied voltage Vd may be set higher.

  In this way, stable combustion is possible even when the dilution or dilution ratio increases and combustion stability deteriorates at low loads.

  Although not shown, the applied voltage Vd and the applied time Td may be simultaneously controlled in consideration of the characteristics shown in FIGS. 7 to 9 in consideration of the in-cylinder pressure, the in-cylinder gas density, and the gas mixture concentration.

  When the load is adjusted by lean combustion or dilution combustion by EGR, the air-fuel mixture is diluted or diluted by EGR gas as the load decreases.

  Therefore, in this embodiment, the applied voltage of the short pulse high voltage applied to the electrode is increased as the load is reduced. By doing so, stable lean or diluted combustion is possible even at extremely low loads.

  In addition, the smaller the load, the higher the applied voltage of the short pulse high voltage applied to the electrode and the shorter the application time, so that a higher voltage can be applied in the corona discharge, which is caused by high-energy accelerated electrons. The combustion reaction is promoted, and even more stable lean or diluted combustion can be realized even at extremely low loads.

  Without being limited to the embodiments described above, various modifications and changes are possible within the scope of the technical idea, and it is obvious that these are also included in the technical scope of the present invention.

  For example, the detection value may be detected directly by a sensor or indirectly by calculating based on another detection value.

It is a lineblock diagram showing a 1st embodiment of an engine ignition device by the present invention. It is an enlarged view near the front-end | tip of the discharge electrode which shows the state at the time of corona discharge. It is a figure explaining the power consumption by corona discharge and arc discharge. It is a flowchart explaining operation | movement of 1st Embodiment of the engine ignition device by this invention. It is a figure which shows an example of the characteristic map for calculating | requiring a target torque. It is a flowchart explaining operation | movement of 2nd Embodiment of the engine ignition device by this invention. It is a figure which shows an example of the characteristic map for setting the applied voltage Vd and the application time Td based on the in-cylinder pressure. It is a figure which shows an example of the characteristic map for setting the applied voltage Vd and the application time Td based on the in-cylinder gas density. It is a figure which shows an example of the characteristic map for setting the applied voltage Vd and the application time Td based on the air-fuel mixture concentration. It is a figure which shows the example of a setting of the applied voltage Vd and the application time Td of 3rd Embodiment of the engine ignition apparatus by this invention. It is a figure which shows the structure of the variable valve mechanism of the engine to which 4th Embodiment of the engine ignition device by this invention is applied. It is a figure explaining operation | movement of a variable valve mechanism. It is a figure which shows the lift amount and opening / closing timing of the intake valve by a variable valve mechanism. It is a figure which shows an example of the application time of the short pulse high voltage applied to an electrode according to load, and an applied voltage. It is a figure which shows an example of the control map of 5th Embodiment of the engine ignition device by this invention.

Explanation of symbols

10 Engine ignition device 11 Discharge electrode (discharge means)
11a Center electrode (positive electrode)
11b Side electrode (negative electrode)
11c Insulator 12 Short pulse high voltage generator 12a Pulse generator 12b High voltage generator 20 Engine 21 Combustion chamber 70 Controller Steps S1, S22 Engine state detection means Steps S4, S23 Discharge control means

Claims (2)

Includes positive and negative electrodes arranged in the combustion chamber of the engine. When short pulse high voltage is applied, corona discharge is generated by low temperature plasma, and then arc discharge by thermal plasma when the positive and negative electrodes are electrically short-circuited. An engine ignition control device that controls engine ignition by a discharge means that generates
The engine is an engine capable of controlling an intake air amount by controlling opening and closing of an intake valve according to a load,
Engine state detecting means for detecting the engine state at the ignition timing;
When reducing the effective intake stroke by controlling the opening and closing of the intake valve,
The lower the load detected as the engine state, the higher the applied voltage of the short pulse high voltage applied to the discharge means, and the application time is such that the discharge by the discharge means does not transition to arc discharge and maintains corona discharge. Discharge control means for shortening;
An engine ignition control device comprising: Includes positive and negative electrodes arranged in the combustion chamber of the engine. When short pulse high voltage is applied, corona discharge is generated by low temperature plasma, and then arc discharge by thermal plasma when the positive and negative electrodes are electrically short-circuited. An engine ignition control device that controls engine ignition by a discharge means that generates
The engine is an engine whose load can be controlled by lean combustion or dilution combustion by EGR,
Engine state detecting means for detecting the engine state at the ignition timing;
If the mixture is diluted or diluted with EGR gas,
The lower the load detected as the engine state, the higher the applied voltage of the short pulse high voltage applied to the discharge means, and the application time is such that the discharge by the discharge means does not transition to arc discharge and maintains corona discharge. Discharge control means for shortening;
An engine ignition control device comprising: