JP2010216270A - Ignition control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition control device for an internal combustion engine, efficiently improving an ignition property of a stratified air-fuel mixture. <P>SOLUTION: The ignition control device for the internal combustion engine 100 includes: a stratified air-fuel mixture forming means (S71) forming, in a combustion chamber 13, the stratified air-fuel mixture higher in air-fuel ratio than that of an air layer or an air-fuel mixture layer formed to the circumference, by fuel injected from a fuel injection valve 26; control means (S72, S73) controlling a radical generating means 25 to generate radical of the stratified air-fuel mixture in the stratified air-fuel mixture; and an ignition means (S74) igniting the stratified air-fuel mixture in which the radical is generated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition control device for an internal combustion engine.

  As a conventional internal combustion engine, when the fuel is directly injected into the cylinder during the compression stroke to form a stratified mixture, ozone is applied to the stratified mixture in the same compression stroke. Some have direct injection. (For example, refer to Patent Document 1). Conventional internal combustion engines have thus improved the self-ignitability of the stratified mixture.

JP 2002-309941 A

  However, in the above-described conventional internal combustion engine, ozone is not selectively generated inside the air-fuel mixture layer, so ozone directly injected into the combustion chamber also exists in the air layer. As a result, ozone present in the air layer hardly contributes to the improvement of self-ignitability, so that the supplied ozone is wasted and the efficiency is poor.

  The present invention has been made paying attention to such conventional problems, and an object thereof is to efficiently improve the ignitability of a stratified mixture.

  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 relates to a fuel injection valve (26, 126) that directly injects fuel into a combustion chamber (13), and a radical generator that is provided in the combustion chamber (13) and generates radicals of gas components in the combustion chamber ( 25), an ignition control device for an internal combustion engine (100), wherein an air layer formed around the combustion chamber (13) by fuel injected from the fuel injection valve (26, 126) or A stratified mixture forming means (S71) for forming a stratified mixture having an air-fuel ratio denser than the mixed gas layer, and a radical generator (25) are controlled so as to generate radicals of the stratified mixture in the stratified mixture. It comprises control means (S72, S73) and ignition means (S74) for igniting the stratified mixture in which radicals are generated.

  According to the present invention, radicals can be selectively generated inside the gas mixture layer before ignition. Therefore, it is possible to react radicals and air-fuel mixture before ignition while suppressing the generation of radicals in the air layer that does not contribute to combustion and suppressing the generation of useless radicals. Can be improved.

It is a schematic block diagram of the engine by 1st Embodiment. It is a flowchart explaining the ignition control of the air-fuel mixture according to the first embodiment. It is a flowchart explaining the process at the time of a stratified self ignition combustion mode. 3 is a table for calculating a target torque based on an accelerator pedal depression amount. It is a map for calculating a target fuel-air ratio. It is a map for determining a combustion mode. It is a figure explaining the ignition promoting effect of the air-fuel mixture due to the presence of radicals in the air-fuel mixture. It is the figure which showed the fuel injection time in the stratified self-ignition combustion mode, and the implementation time of non-equilibrium plasma discharge. It is a figure explaining the mode in a cylinder at the time of stratified self-ignition combustion mode. This is a time when the fuel injection timing and the non-equilibrium plasma discharge execution timing in the stratified self-ignition combustion mode according to the second embodiment are shown. It is a schematic block diagram of the engine by 3rd Embodiment. It is a schematic block diagram of the engine by 4th Embodiment. It is a schematic block diagram of the engine by 5th Embodiment. It is a schematic block diagram of the engine by 6th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an engine 100 according to a first embodiment of the present invention.

  The engine 100 includes a cylinder block 1, a cylinder head 2, and a controller 3.

  A plurality of cylinders 11 are formed in the cylinder block 1. A piston 12 that receives combustion pressure and reciprocates inside the cylinder 11 is housed inside the cylinder 11. The cylinder block 1, the cylinder head 2, and the piston 12 define a pent roof type combustion chamber 13.

  The cylinder head 2 includes an intake port 21, an exhaust port 22, an intake valve 23, an exhaust valve 24, a discharge device 25, and a fuel injection valve 26.

  The intake port 21 is a flow path through which air sucked into the cylinder 11 flows, and opens on one inclined surface of the combustion chamber top wall.

  The exhaust port 22 is a flow path through which the exhaust discharged from the cylinder 11 flows, and opens to the other inclined surface of the combustion chamber top wall.

  The intake valve 23 opens and closes the opening of the combustion chamber 13 and the intake port 21 in accordance with the vertical movement of the piston 12.

  The exhaust valve 24 opens and closes the opening of the combustion chamber 13 and the exhaust port 22 according to the vertical movement of the piston 12.

  The discharge device 25 includes an electrode 251 and a voltage generator 252.

  The electrode 251 is made of a conductor and penetrates the dielectric (insulator) 253 in the axial direction, and a part on the tip side protrudes into the combustion chamber 13. The cavity 12a formed on the piston crown also serves as the ground electrode of the electrode 251.

  The voltage generator 252 is connected to the electrode 251 and applies a voltage to the electrode 251.

  The discharge device 25 is configured as described above, and in a transient discharge form before transition to equilibrium plasma discharge (also referred to as arc discharge) when a high voltage with a short pulse width is applied by the voltage generator 252. Causes a non-equilibrium plasma discharge. Thereby, the radical of a gas component is produced | generated inside the combustion chamber 13, and the discharge device 25 functions as a radical production | generation apparatus at this time.

  On the other hand, when a high voltage with a long pulse width is applied by the voltage generator 252, an equilibrium plasma discharge occurs. At this time, the discharge device 25 functions as an ignition device.

  The fuel injection valve 26 directly injects fuel toward the cavity 12a at a predetermined fuel injection timing during the compression stroke. The fuel injected from the fuel injection valve 26 is guided to the vicinity of the electrode 251 by the cavity 12a.

  The controller 3 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 3 receives signals from various sensors that detect the operating state of the engine 100 such as an accelerator stroke sensor 31, a crank angle sensor 32, and an airflow sensor 33. The controller 3 selects an optimal combustion mode according to the operating state and ignites the air-fuel mixture. Then, the voltage generator 252 is controlled in accordance with the combustion mode, and the voltage value (hereinafter referred to as “applied voltage”) applied to the electrode 251 and the applied wave number (repetition frequency × discharge time) are controlled. Hereinafter, the ignition control of the air-fuel mixture will be described.

  FIG. 2 is a flowchart illustrating the ignition control according to the present embodiment. The controller 3 executes this routine at a predetermined calculation cycle (for example, 10 ms) while the engine 100 is operating.

  In step S <b> 1, the controller 3 reads the accelerator pedal depression amount detected by the accelerator stroke sensor 31, the engine 100 rotational speed detected by the crank angle sensor 32, and the intake air amount detected by the airflow sensor 33.

  In step S2, the controller 3 refers to a table in FIG. 4 to be described later, and calculates a target torque based on the accelerator pedal depression amount.

  In step S3, the controller 3 refers to a map of FIG. 5 described later, and calculates a target fuel-air ratio based on the engine speed and the target torque. Here, the fuel-air ratio means the reciprocal of the excess air ratio.

  In step S4, the controller 3 calculates a target fuel injection amount. Specifically, first, the basic fuel injection amount is calculated based on the intake air amount and the engine speed. Next, various corrections are performed on the basic fuel injection amount to obtain a target fuel injection amount.

  In step S5, the controller 3 determines whether or not the engine 100 is operating in the self-ignition combustion mode region with reference to a map of FIG. If the controller 3 is operating in the self-ignition combustion mode region, the process proceeds to step S6, and if not, the process proceeds to step S9.

  In step S6, the controller 3 refers again to the map of FIG. 6 described later, and determines whether or not the engine 100 is operating in the stratified self-ignition combustion mode region. If the controller 3 is operating in the stratified self-ignition combustion mode region, the process proceeds to step S7, and if not, the process proceeds to step S8.

  In step S7, the controller 3 shifts to the stratified self-ignition combustion mode. In the stratified self-ignition combustion mode, fuel is injected during the compression stroke to form a stratified mixture, and at the same time as the fuel injection, non-equilibrium plasma discharge is performed to generate radicals that enhance ignitability in the stratified mixture. Generate. Thereafter, the stratified mixture whose ignitability is enhanced by radicals is burned by self-ignition. Processing in the stratified self-ignition combustion mode will be described later with reference to FIG.

  In step S8, the controller 3 shifts to the homogeneous auto-ignition combustion mode. In the homogeneous auto-ignition combustion mode, a homogeneous mixture is formed by the fuel injected during the intake stroke, and the homogeneous mixture is self-ignited and combusted.

  In step S9, the controller 3 shifts to the flame propagation combustion mode. In the flame propagation combustion mode, a homogeneous mixture is formed by the fuel injected during the intake stroke, and the homogeneous mixture is ignited and burned by balanced plasma discharge.

  FIG. 3 is a flowchart for explaining processing in the stratified self-ignition combustion mode.

  In step S71, the controller 3 sets the fuel injection start time. Specifically, it is set with reference to a map determined in advance by experiments or the like based on the engine speed and the target torque. The fuel injection start time here is set during the compression stroke in order to form a stratified mixture. The map according to the present embodiment is a map in which the fuel injection start timing is advanced as the engine rotational speed is higher.

  In step S72, the controller 3 sets a non-equilibrium plasma discharge start time. Here, the non-equilibrium plasma discharge start timing is set to be the same as the combustion injection start timing, but may be set to the retard side with respect to the fuel injection start timing.

  In step S73, the controller 3 sets a non-equilibrium plasma discharge end time according to the gas temperature inside the cylinder (hereinafter referred to as “in-cylinder temperature”). A specific setting method will be described later with reference to FIG.

  In step S74, the compression of the combustion chamber 13 near the top dead center corresponding to the ignition means causes the stratified mixture whose ignitability is improved by radicals to self-ignite and burn.

  FIG. 4 is a table for calculating the target torque based on the accelerator pedal depression amount. This table is determined in advance by experiments or the like and stored in the controller 3.

  As shown in FIG. 4, the target torque increases as the accelerator pedal depression amount increases.

  FIG. 5 is a map for calculating the target fuel-air ratio. This map is determined in advance by experiments or the like and stored in the controller 3.

  As shown in FIG. 5, the target fuel-air ratio increases as the engine speed increases and as the target torque increases.

  FIG. 6 is a map for determining the combustion mode. This map is determined in advance by experiments or the like and stored in the controller 3.

  As shown in FIG. 6, the combustion mode is roughly divided into a flame propagation combustion mode and a self-ignition combustion mode, and the self-ignition combustion mode is further divided into a homogeneous auto-ignition combustion mode and a stratified self-ignition combustion mode. .

  The controller 3 selects the flame propagation combustion mode when the engine 100 is operating at a high rotation speed or a high load. On the other hand, the self-ignition combustion mode is selected when operating from low to medium rotation and from low to medium load.

  When the self-ignition combustion mode is selected, the homogeneous auto-ignition combustion mode is selected when the load is relatively high, and the stratified self-ignition combustion mode is selected when the load is relatively low.

  FIG. 7 is a diagram for explaining the ignition promotion effect of the air-fuel mixture due to the presence of radicals in the air-fuel mixture.

  As shown in FIG. 7, according to the inventors' extensive research, the ignition promotion effect of the air-fuel mixture due to the presence of radicals in the air-fuel mixture mainly depends on the in-cylinder temperature, and becomes larger as the in-cylinder temperature is lower. I found out that That is, as the in-cylinder temperature increases, the effect of promoting the ignition of the air-fuel mixture due to the presence of radicals in the air-fuel mixture decreases, and when the in-cylinder temperature becomes 1000 [K] or higher, the effect of accelerating ignition becomes substantially zero.

  Therefore, in this embodiment, a limit value (hereinafter referred to as “limit temperature”) of the in-cylinder temperature at which the ignition of the mixture is effectively promoted by the presence of radicals in the mixture is set in advance, and the in-cylinder temperature is The crank angle at which the limit temperature is reached is the non-equilibrium plasma discharge end timing. In this embodiment, the limit temperature is set to 800 [K], but may be changed as appropriate for each engine specification.

  In addition, the effect of promoting the ignition of the air-fuel mixture due to the presence of radicals in the air-fuel mixture is also slightly affected by the gas pressure inside the cylinder (hereinafter referred to as “cylinder pressure”). Become. Therefore, the non-equilibrium plasma discharge end time may be set in consideration of the in-cylinder pressure.

  FIG. 8 is a diagram showing the fuel injection timing and the non-equilibrium plasma discharge timing in the stratified self-ignition combustion mode.

  As shown in FIG. 8, in the stratified self-ignition combustion mode, fuel injection is started during the compression stroke in order to form a stratified mixture. In this embodiment, non-equilibrium plasma discharge is started simultaneously with the start of fuel injection. The non-equilibrium plasma discharge is performed until the in-cylinder temperature reaches the limit temperature even after the fuel injection is completed.

  FIG. 9 is a diagram for explaining a state in the cylinder in the stratified self-ignition combustion mode.

  FIG. 9A is a diagram illustrating a state in the cylinder when both fuel injection and non-equilibrium plasma discharge are performed.

  As shown in FIG. 9A, when fuel injection is started toward the cavity 12a during the compression stroke, the injected fuel forms a stratified mixture inside the cavity 12a while entraining surrounding air. In the following description, a portion of the stratified air-fuel mixture that is formed inside the cavity 12a and has a relatively higher air-fuel ratio than the air layer (or the air-fuel mixture layer with a low air-fuel ratio) formed around the air-fuel mixture layer will be described. The other part where the fuel is not diffused is called the air layer. The air-fuel mixture layer of this embodiment is an air-fuel mixture that is thinner (lean) than stoichiometric.

  When non-equilibrium plasma discharge is started simultaneously with fuel injection, a plurality of streamers are generated from the electrode 251 toward the inner wall of the cavity 12a.

  As described above, when non-equilibrium plasma discharge is performed inside the gas mixture layer, high energy electrons generated by the non-equilibrium plasma collide with molecules inside the gas mixture layer to induce molecular dissociation. Thereby, radicals (chemically active species) 44 can be selectively generated inside the gas mixture layer. That is, radical generation in the air layer that hardly contributes to the improvement of self-ignitability can be avoided. The radicals generated at this time are mainly oxygen radicals, hydrogen radicals, and hydrocarbon radicals.

  When radicals are present inside the gas mixture, the low-temperature oxidation reaction of the gas mixture is promoted from a lower temperature than when it is not present, and various intermediate products are generated and finally mixed. Qi ignitability is improved.

  Moreover, as shown in FIG. 9, if the radical generation range by the discharge device 25 is substantially matched to the formation range of the stratified mixture, radical generation in the air layer that hardly contributes to the improvement of self-ignitability is avoided. In addition, self-ignitability can be efficiently improved by radical generation. Further, for example, as in the conventional example, in the case of injecting ozone, there is a problem in that the mixture layer is blown off by the injected ozone and affects the mixture formation. Further, there is a problem that the penetration into the air-fuel mixture layer becomes insufficient and the contribution to activation (improvement of ignitability) decreases. On the other hand, such a problem does not occur if radicals of the stratified mixture are generated in the stratified mixture as in this embodiment.

  FIG. 9B is a diagram illustrating a state in the cylinder when only non-equilibrium plasma discharge is performed after the fuel injection is completed.

  As shown in FIG. 9B, even after the fuel injection is completed and the stratified mixture is formed, non-equilibrium plasma discharge is continuously performed inside the mixture layer, Generate radicals.

  FIG. 9C is a diagram illustrating a state in the cylinder before the non-equilibrium plasma discharge is finished and combustion by self-ignition occurs.

  As shown in FIG. 9C, when the piston 12 rises and the in-cylinder temperature becomes higher than the limit temperature, the non-equilibrium plasma discharge is terminated. This is because, as described above, when the in-cylinder temperature becomes higher than the limit temperature, the ignition promotion effect of the air-fuel mixture due to the presence of radicals in the air-fuel mixture layer is greatly reduced.

  According to the present embodiment described above, in the stratified self-ignition combustion mode, an air-fuel mixture layer richer than the stoichiometric air-fuel ratio is formed inside the cavity 12a, and non-equilibrium plasma discharge is performed inside the air-fuel mixture layer. Later, a stratified mixture consisting of a mixture layer and an air layer was self-ignited and combusted.

  Thereby, radicals can be selectively generated inside the gas mixture layer before ignition. Therefore, it is possible to react radicals and air-fuel mixture before ignition while suppressing the generation of radicals in the air layer that does not contribute to combustion and suppressing the generation of useless radicals. Can be improved.

  Further, since ozone is not directly injected into the combustion chamber 13 as in the conventional example, the fuel spray flow is not disturbed, and the formation of the stratified mixture is not disturbed. Further, if ozone is to be supplied to the combustion chamber 13 during the compression stroke in which the combustion chamber 13 is at a relatively high pressure, it is necessary to increase the pressure of ozone generated outside the combustion chamber 13, and the system is compared with this embodiment. It becomes complicated. Since ozone causes thermal decomposition, wall deposition, and disappearance, if such unstable ozone is supplied to the combustion chamber 13 through a complicated system, the amount of ozone is greatly reduced before being supplied to the combustion chamber 13. There is also a risk of it.

  According to this embodiment, the end time of the non-equilibrium plasma discharge is set according to the in-cylinder temperature. Specifically, the effect of promoting the ignition of the air-fuel mixture due to the presence of radicals in the air-fuel mixture decreases as the in-cylinder temperature increases, so that the in-cylinder temperature reaches the limit temperature at which the ignition acceleration effect starts to decrease significantly. When reached, the non-equilibrium plasma discharge was terminated.

  Thereby, it can suppress that a radical is produced | generated at the time of the ignition promotion effect of air-fuel | gaseous mixture being small, and can suppress useless non-equilibrium plasma discharge. As a result, the amount of power supplied to the voltage generator 252 can be reduced, so that fuel efficiency can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment in that fuel is injected in two portions during the compression stroke. Hereinafter, the difference will be mainly described. In the following embodiments, the same reference numerals are used for portions that perform the same functions as those in the first embodiment described above, and repeated descriptions are omitted as appropriate.

  FIG. 10 shows the fuel injection timing and non-equilibrium plasma discharge execution timing in the stratified self-ignition combustion mode according to the present embodiment.

  As shown in FIG. 10, in this embodiment, fuel is injected in two during the compression stroke, and non-equilibrium plasma discharge is started simultaneously with the first injection. Thereby, since a gas mixture and a radical can be made to react for a comparatively long period before ignition, the ignitability of a stratified gas mixture can be improved. The second fuel injection is performed after the end of the non-equilibrium plasma discharge, but the non-equilibrium plasma discharge may be performed.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, the configuration of the discharge device 25 is different from that of the first embodiment. Hereinafter, the difference will be mainly described.

  FIG. 11 is a schematic configuration diagram of an engine 100 according to the third embodiment of the present invention.

  In the first embodiment, multiple high-voltage pulse waves are applied as radical generating means, and the electric field is interrupted before a transition to arc discharge to generate a plurality of streamers to generate radicals.

  However, as shown in FIG. 11, the surface of the electrode 251 protruding into the combustion chamber 13 is covered with a dielectric 253, and a high voltage high frequency is applied to the electrode 251 to cause non-equilibrium plasma discharge, toward the inner wall of the cavity 12a. Multiple streamers may be generated to generate radicals. In principle, the presence of the dielectric 253 between the electrode 251 and the ground electrode (surface of the cavity 12a) suppresses the transition to arc discharge, and the wide space between the surface of the dielectric 253 and the ground electrode is suppressed. Multiple streamers are generated.

  Even if it is a structure like this embodiment, the effect similar to 1st Embodiment can be acquired.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the present embodiment, the configuration of the discharge device 25 is different from that of the first embodiment. Hereinafter, the difference will be mainly described.

  FIG. 12 is a schematic configuration diagram of an engine 100 according to the fourth embodiment of the present invention.

  In the third embodiment, the surface of the electrode 251 is covered with the dielectric 253. However, as shown in FIG. 12, the surface of the cavity 12a may be covered with the dielectric 253 to generate a plurality of streamers.

  Even if it is a structure like this embodiment, the effect similar to 1st Embodiment can be acquired.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. This embodiment is different from the first embodiment in the shape of the cavity 12a and the installation position of the fuel injection valve 26. Hereinafter, the difference will be mainly described.

  FIG. 13 is a schematic configuration diagram of an engine 100 according to the fifth embodiment of the present invention.

  In the first embodiment, the fuel injection valve 26 is provided near the center of the top wall of the combustion chamber, and the cavity 12a is formed in the center of the piston crown so as to correspond thereto. May be provided near the side wall of the combustion chamber 13. In this case, the shape of the cavity 12a may be changed so that the injected fuel forms an air-fuel mixture layer around the electrode 251 along the inner wall of the cavity 12a.

  Even if it is a structure like this embodiment, the effect similar to 1st Embodiment can be acquired.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. This embodiment is different from the first embodiment in that the cavity 12a is not formed in the piston 12. Hereinafter, the difference will be mainly described.

  FIG. 14 is a schematic configuration diagram of an engine 100 according to the sixth embodiment of the present invention.

  In each of the above embodiments, the multi-hole type fuel injection valve 26 is used. However, in this embodiment, the outward injection type fuel injection valve 126 is used to control the injection amount, and as shown in FIG. A stratified mixture may be formed without providing the cavity 12a. A high voltage radio wave is applied to the electrode 251. Also in this case, the piston crown surface becomes a ground electrode, and a plurality of streamers are generated.

  Even if it is a structure like this embodiment, the effect similar to 1st Embodiment can be acquired.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, other non-equilibrium plasma forming means not described here may be used as long as the specifications are for an electrode and a power source that can form non-equilibrium plasma. For example, a method of forming non-equilibrium plasma using a microwave or the like may be used.

12 Piston (Grounding electrode)
13 Combustion chamber 26 Fuel injection valve 100 Engine (internal combustion engine)
251 Electrode 252 Voltage generator S71 Stratified gas mixture forming means S72 Control means S73 Control means S74 Ignition means

Claims (9)

A fuel injection valve that injects fuel directly into the combustion chamber;
A radical generator that is provided in the combustion chamber and generates radicals of gas components in the combustion chamber;
An ignition control device for an internal combustion engine comprising:
Stratified mixture forming means for forming a stratified mixture with an air-fuel ratio denser than the air layer or mixture layer formed in the combustion chamber by the fuel injected from the fuel injection valve;
Control means for controlling the radical generating device so as to generate radicals of the stratified gas mixture in the stratified gas mixture;
Ignition means for igniting the stratified gas mixture in which radicals are generated;
An ignition control device for an internal combustion engine, comprising:   2. The ignition control device for an internal combustion engine according to claim 1, wherein a radical generation range by the radical generation device substantially coincides with a formation range of the stratified mixture. The radical generator is
An electrode provided in the combustion chamber;
A ground electrode provided in the combustion chamber so as to face the electrode;
A voltage generator for applying a voltage to the electrodes;
With
The stratified gas mixture forming means includes:
The fuel injected from the fuel injection valve forms a stratified mixture having an air-fuel ratio that is richer than the air layer or mixture layer formed between the electrode and the ground electrode,
The control means includes
The voltage is applied to the electrode by the voltage generator to generate a non-equilibrium plasma discharge between the electrode and the ground electrode to generate radicals in the stratified gas mixture. 3. An ignition control device for an internal combustion engine according to 2. The control means includes
The ignition control device for an internal combustion engine according to any one of claims 1 to 3, wherein generation of the radical is started simultaneously with fuel injection or after fuel injection. The control means includes
The ignition control device for an internal combustion engine according to any one of claims 1 to 4, wherein the generation of the radical is terminated when an in-cylinder gas temperature becomes higher than a predetermined temperature. The control means includes
The ignition control device for an internal combustion engine according to any one of claims 1 to 4, wherein the radical generation end time is determined based on an in-cylinder gas temperature and an in-cylinder gas pressure. The stratified gas mixture forming means includes:
The ignition of the internal combustion engine according to any one of claims 1 to 6, wherein fuel is injected during a compression stroke to form the stratified mixture between the electrode and the ground electrode. Control device. The stratified mixture forming means forms the stratified mixture between the electrode and the ground electrode by injecting fuel into a plurality of times,
The ignition control of the internal combustion engine according to any one of claims 1 to 7, wherein the radical generation device generates the radical in the stratified mixture formed by an initial fuel injection. apparatus. The ignition means is
9. The ignition control device for an internal combustion engine according to claim 1, wherein the stratified mixture is compressed and self-ignited.