JP2006336476A - Control device for cylinder direct injection type spark ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid thermal degradation of a catalyst due to an excessively high temperature while attaining early activation of the catalyst and HC reduction by after-burning with a considerable delay of ignition timing. <P>SOLUTION: At the cold start of an internal combustion engine which requires the early temperature rise of a catalytic converter, the ignition timing is set after the compression top dead center, and super retard combustion of injecting fuel before the ignition timing and after the compression top dead center is performed. Turbulence in a cylinder is improved by high pressure fuel injection immediately before the ignition timing, and flame propagation is accelerated to achieve stable combustion. In this super retard combustion, an exhaust temperature becomes very high, and if it continues to the complete active temperature of the catalyst, there is a problem of thermal degradation. A top dead center injection operation mode is thereby released in a predetermined stage before complete activity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-cylinder direct-injection spark ignition internal combustion engine that directly injects fuel into a cylinder, and in particular, injection at a cold start in which early temperature rise (early activation) of an exhaust system catalytic converter is required. It relates to the control of timing and ignition timing.

In Patent Document 1, as a catalyst warm-up method for a direct injection spark ignition internal combustion engine, a period from an intake stroke to an ignition timing when the exhaust gas catalytic converter is in an unwarmed state lower than an activation temperature. In this case, it is possible to spread the fuel by the late injection in which the air-fuel mixture having a partial air-fuel ratio concentration is formed in the combustion chamber, the fuel is injected before this late injection, and the fuel of the late injection and the combustion of the late injection And at least two split injections of early injection for generating an air-fuel mixture leaner than the stoichiometric air-fuel ratio in the combustion chamber, and retarding the ignition timing by a predetermined amount from the MBT point, and no engine load A technique is described in which the ignition timing is set before the compression top dead center in the region, and the ignition timing is retarded until the compression top dead center in the low speed and low load region excluding the no-load region. The latter-stage injection is performed, for example, at 120 ° BTDC to 45 ° BTDC after the middle of the compression stroke.
Japanese Patent No. 3325230

  For early activation of the catalyst when the internal combustion engine is cold and HC reduction due to afterburning, retarding the ignition timing is effective. To obtain a greater effect, ignition after compression top dead center (ATDC) Ignition) is desirable. In order to perform stable combustion by ATDC ignition, it is necessary to shorten the combustion period. For this reason, it is necessary to increase the combustion speed (flame propagation speed) by strengthening the turbulence in the cylinder.

  In order to strengthen such disturbance, it is conceivable that the disturbance is generated in the cylinder by the energy of the fuel spray injected at a high pressure in the cylinder.

  However, in Patent Document 1, the first fuel injection (early injection) is performed during the intake stroke, and the second fuel injection (late injection) is performed from 120 ° BTDC to 45 ° BTDC during the compression stroke. Yes. As described above, before the last fuel injection is before the compression top dead center, even if the spray generates turbulence in the cylinder, the turbulence is attenuated after the compression top dead center, and the flame propagation in ATDC ignition Does not contribute to speed increase.

  For example, FIG. 12 shows the magnitude of turbulence in a cylinder when a gas flow control valve (for example, a tumble control valve) provided in an intake port is operated and when such a gas flow control valve is not provided. As shown, the turbulence (part A) generated during the intake stroke by operating the gas flow control valve is attenuated as the compression stroke progresses, and is temporarily accompanied by the collapse of the tumble flow in the latter half of the compression stroke. Although the turbulence increases (the portion indicated by reference symbol B), after the compression top dead center, as shown by the reference symbol C, it rapidly attenuates, and combustion improvement (improving flame propagation) using the turbulence cannot be expected so much. The same applies to turbulence caused by fuel spray, and even if turbulence is generated by fuel injection before compression top dead center, it does not contribute to ignition combustion after compression top dead center.

  For this reason, ATDC ignition is more advantageous for increasing exhaust temperature and reducing HC, but combustion stability is not established. Therefore, in Patent Document 1, the ignition timing is set to before compression top dead center (BTDC ignition) in the no-load region. Yes.

  The present invention aims to improve combustion stability in ATDC ignition for early activation of the catalyst and HC reduction based on such a situation.

  The present invention requires an early temperature rise of an exhaust system catalytic converter in a control device for a direct injection spark ignition internal combustion engine that includes a fuel injection valve that directly injects fuel into the cylinder and includes an ignition plug. When the internal combustion engine is cold-started, the ignition timing is set after the compression top dead center, and super retard combustion is performed in which fuel is injected before the ignition timing and after the compression top dead center. In particular, the super retard combustion is not continued until the catalyst is fully activated, but is canceled based on the determination of the temperature state of the catalytic converter before the catalyst is fully activated.

  In other words, after the compression top dead center, the turbulence generated in the intake stroke and the compression stroke is attenuated, but the in-cylinder turbulence is generated and strengthened by the fuel injection performed during the expansion stroke after the compression top dead center. Flame propagation with ATDC ignition is facilitated. Therefore, super retard combustion with the ignition timing after the compression top dead center is established stably.

  Here, in the super retard combustion in which the ignition timing is significantly retarded as described above, for example, the exhaust temperature becomes very high as compared with the conventional technology such as Patent Document 1 in which BTDC ignition is performed at the time of idling. In the process in which the temperature of the catalytic converter rises, the temperature gradient inside the catalytic converter tends to become very steep. That is, there is a concern that only the upstream portion such as the monolithic ceramic catalyst carrier rapidly becomes high in temperature and the thermal strain increases. Also, since the exhaust temperature becomes very high, even if it is determined that the catalyst temperature has reached the activation temperature and the super retard combustion is stopped, the heat capacity of exhaust system parts upstream of the catalytic converter, the reaction heat of the catalyst itself, etc. As a result, the internal temperature of the catalytic converter continues to rise, and the internal temperature of the catalytic converter may overshoot to the catalyst deterioration temperature.

  Therefore, in the present invention, the super retard combustion is not continued until the catalyst is fully activated, and is canceled based on the determination of the temperature state of the catalytic converter before the catalyst is completely activated.

  In one aspect of the present invention, the temperature state of the catalytic converter is determined from the inlet temperature of the catalytic converter and the rate of change of the inlet temperature. For example, the super retard combustion is canceled when the inlet temperature is lower as the change rate of the inlet temperature is higher.

  In one aspect of the present invention, the temperature state of the catalytic converter is determined from the inlet temperature and the internal temperature of the catalytic converter. For example, the super retard combustion is canceled when the internal temperature is lower as the inlet temperature is higher.

  As described above, by judging the timing of canceling the super retard combustion from the inlet temperature of the catalytic converter and the rate of change thereof, or the inlet temperature and the internal temperature, the excessive overshoot of the internal temperature or the excessive thermal gradient is detected. Occurrence can be avoided.

  According to the present invention, it is possible to sufficiently ensure the combustion stability of the super retard combustion in which the ignition timing is set after the compression top dead center, and at the time of cold start, early activation of the catalyst and reduction of HC due to afterburning. Can be achieved. And since super retard combustion is canceled at an appropriate timing before the catalytic converter is fully activated, it is possible to avoid thermal deterioration due to excessive overshooting of the catalyst temperature, damage to the catalyst carrier due to extreme temperature gradient, etc. it can.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration explanatory view showing a system configuration of a direct injection type spark ignition internal combustion engine to which the present invention is applied.

  An intake passage 4 is connected to the combustion chamber 3 formed by the piston 2 of the internal combustion engine 1 via an intake valve (not shown), and an exhaust passage 5 is connected via an exhaust valve (not shown). Has been. The intake passage 4 is provided with an air flow meter 6 for detecting the amount of intake air, and an electronically controlled throttle valve 7 whose opening degree is controlled via an actuator 8 by a control signal. A catalyst converter 10 for purifying exhaust gas is disposed in the exhaust passage 5, and air-fuel ratio sensors 11 and 12 are provided on the upstream side and the downstream side, respectively. Furthermore, in this embodiment, in order to determine the temperature state of the catalytic converter 10, a catalyst inlet temperature sensor 13 disposed at the inlet portion of the catalytic converter 10 is provided along with the upstream air-fuel ratio sensor 11.

  A spark plug 14 is disposed at the central top of the combustion chamber 3. A fuel injection valve 15 that directly injects fuel into the combustion chamber 3 is disposed on the side of the combustion chamber 3 on the intake passage 4 side. The fuel that has been regulated to a predetermined pressure by the high-pressure fuel pump 16 and the pressure regulator 17 is supplied to the fuel injection valve 15 via the high-pressure fuel passage 18. Therefore, when the fuel injection valve 15 of each cylinder is opened by the control pulse, an amount of fuel corresponding to the valve opening period is injected. Reference numeral 19 denotes a fuel pressure sensor that detects the fuel pressure, and 20 denotes a low-pressure fuel pump that sends fuel to the high-pressure fuel pump 16.

  In addition, the internal combustion engine 1 is provided with a water temperature sensor 21 for detecting the engine cooling water temperature and a crank angle sensor 22 for detecting a crank angle. Further, an accelerator opening sensor 23 is provided for detecting the amount of depression of the accelerator pedal by the driver.

  The fuel injection amount, injection timing, ignition timing, etc. of the internal combustion engine 1 are controlled by the control unit 25. The control unit 25 receives detection signals from the various sensors described above. The control unit 25 determines the combustion method, that is, the homogeneous combustion or the stratified combustion, in accordance with the engine operating conditions detected by these input signals, and according to this, the electronic control throttle valve 7 is opened. The fuel injection timing and fuel injection amount of the fuel injection valve 15, the ignition timing of the spark plug 14, and the like are controlled. After the warm-up is completed, in a predetermined region on the low-speed and low-load side, as normal stratified combustion operation, fuel injection is performed at an appropriate time in the compression stroke, and ignition is performed before the compression top dead center. Done. The fuel spray is collected in the vicinity of the spark plug 14, thereby achieving extremely lean stratified combustion with an air-fuel ratio of about 30 to 40. Further, in a predetermined region on the high speed and high load side, as normal homogeneous combustion operation, fuel injection is performed during the intake stroke, and ignition is performed in the vicinity of the MBT point before the compression top dead center. In this case, the fuel becomes a homogeneous mixture in the cylinder. As the homogeneous combustion operation, there are homogeneous stoichiometric combustion in which the air-fuel ratio is the stoichiometric air-fuel ratio and homogeneous lean combustion in which the air-fuel ratio is lean about 20 to 30 depending on the operating conditions.

  The present invention performs super retard combustion so that the exhaust gas temperature becomes high at the time of cold start of the internal combustion engine 1 where early temperature rise of the catalytic converter 10 is required. The fuel injection timing and ignition timing will be described with reference to FIG.

  FIG. 2 shows three examples of super retard combustion. In Example 1, the ignition timing is set to 15 ° to 30 ° ATDC (for example, 20 ° ATDC), and the fuel injection timing (specifically, the fuel injection start timing) is shown. Is set after the compression top dead center and before the ignition timing. At this time, the air-fuel ratio is set to the stoichiometric air-fuel ratio or slightly lean (about 16 to 17).

  That is, in order to promote catalyst warm-up and reduce HC, ignition timing retardation is effective, and ignition after top dead center (ATDC ignition) is desirable, but in order to perform stable combustion with ATDC ignition, It is necessary to shorten the combustion period, and for this purpose, flame propagation due to turbulence must be promoted. As described above, after the compression top dead center, the turbulence generated in the intake stroke and the compression stroke is attenuated, but in the present invention, by the high pressure fuel injection performed during the expansion stroke after the compression top dead center. The gas flow is generated, and thereby the turbulence in the cylinder can be generated and strengthened. Therefore, flame propagation by ATDC ignition is promoted and stable combustion is possible.

  The second embodiment in FIG. 2 is an example in which the fuel injection is divided into two, and the first fuel injection is performed during the intake stroke, and the second fuel injection is performed after the compression top dead center. The ignition timing and the air-fuel ratio (the air-fuel ratio obtained by combining the two injections) are the same as those in the first embodiment.

  As described above, when fuel injection (intake stroke injection) is performed during the intake stroke prior to fuel injection after the compression top dead center (expansion stroke injection), disturbance due to fuel spray in the intake stroke injection is attenuated in the latter half of the compression stroke. However, since the injected fuel is diffused throughout the combustion chamber and contributes to the promotion of HC afterburning by ATDC ignition, the HC reduction and It is effective for raising the exhaust temperature.

  In the third embodiment of FIG. 2, the fuel injection is divided into two, the first fuel injection is performed in the compression stroke, and the second fuel injection is performed after the compression top dead center. As described above, when the fuel injection (compression stroke injection) is performed during the compression stroke prior to the fuel injection after the compression top dead center (expansion stroke injection), the compression stroke injection is compared with the intake stroke injection of the second embodiment. However, since the disturbance of the turbulence due to the fuel spray is delayed, the turbulence due to the first fuel injection remains, and the second fuel injection is performed after the compression top dead center, which is generated by the first fuel injection. The turbulence can be strengthened to promote the turbulence, and the gas flow can be further strengthened near the compression top dead center.

  In the case of Example 3, the first compression stroke injection may be in the first half of the compression stroke, but if it is set in the second half of the compression stroke (after 90 ° BTDC), the disturbance near the top dead center can be further increased. In particular, if the first compression stroke injection is 45 ° BTDC or later, more desirably 20 ° BTDC or later, the gas flow after compression top dead center can be further enhanced.

  As described above, according to the super retarded combustion of the first to third embodiments, the turbulence in the cylinder can be generated and strengthened by the fuel spray immediately before the ignition, and the flame propagation is promoted to perform stable combustion. be able to. In particular, by retarding the ignition timing from 15 ° to 30 ° ATDC, a sufficient afterburning effect for early activation of the catalyst and reduction of HC can be obtained. In other words, even if the ignition timing is greatly delayed in this way, the fuel injection is delayed until just before that, and the generation time of the turbulence is also delayed, so that the combustion improvement by improving the flame propagation can be achieved.

  Here, in the above-described super retard combustion, the exhaust gas temperature can be obtained extremely high, so the catalytic converter 10 is rapidly heated from the upstream side, and there is a concern of thermal distortion of the catalytic converter 10 or excessive temperature rise. . Therefore, in this embodiment, the combustion mode is switched while monitoring the temperature state of the catalytic converter 10 by the processing as shown in FIG.

  First, in step 1, the inlet temperature T of the catalytic converter 10 detected by the catalyst inlet temperature sensor 13 is read, and the rate of change, that is, the amount of change dT per unit time is obtained. Next, whether or not the catalyst is active in step 2 is determined from, for example, the cooling water temperature at the start of the engine or the catalyst inlet temperature T at the start. If the catalyst is already in an active state as in warm-up restart, the routine proceeds to step 5 and the above-described normal stratified combustion operation or homogeneous combustion operation is performed.

  If the catalyst is in an inactive state as in the cold start, the process proceeds to step 3 to execute the super retard combustion described above. As a result, the exhaust temperature rises rapidly.

  Thereafter, in step 4, it is determined whether or not the temperature state of the catalytic converter 10 has reached a predetermined stage before the catalyst is fully activated, based on the catalyst inlet temperature T and its change rate dT. Specifically, from the catalyst inlet temperature T and the change rate dT, it is repeatedly determined whether the region is in the permission condition or the prohibition condition of the characteristic as shown in FIG. Continue burning. When the prohibited condition region is entered, the routine proceeds from step 4 to step 5, where the super retard combustion is canceled and the routine shifts to normal control. The region of the prohibition condition is set so that the catalyst temperature that rises later even after the release of the super retard combustion does not excessively overshoot beyond the complete activation temperature, and in particular, the change rate dT is large. The higher the catalyst inlet temperature T, the higher the super retarded combustion is released. Therefore, thermal distortion due to excessive overshoot of the catalyst temperature and extreme temperature gradient is prevented.

  Hereinafter, the temperature change of the catalytic converter 10 will be described. FIG. 5 shows, as an example, changes in the inlet temperature (approximately equal to the exhaust gas temperature) and the internal temperature of the catalytic converter after the cold start, and the broken line shows the characteristics when the normal combustion operation is continued after the start. Indicates the characteristics when super retard combustion is continued after starting. As shown in the figure, in the super retard combustion, the exhaust temperature (inlet temperature) rises sharply after starting, and the time required for the internal temperature to reach the catalyst activation temperature (complete activation temperature) T1 is greatly shortened. However, paying attention to the temperature difference between the inlet temperature and the internal temperature (in other words, the temperature gradient of the catalyst carrier), the temperature difference ΔT when the internal temperature reaches the catalyst activation temperature T1 is due to super retarded combustion indicated by a solid line. The rapid heating becomes larger than the gentle heating shown by the broken line. That is, when the temperature is rapidly increased by super retard combustion, generally, thermal distortion tends to increase.

  FIG. 6 shows a comparative example when the super retard combustion is canceled when the internal temperature reaches the catalyst activation temperature T1. In this case, even after canceling the super retard combustion, the internal temperature of the catalytic converter continues to increase due to the heat capacity of the exhaust system components upstream of the catalytic converter, the reaction heat of the catalyst itself, etc. There is a risk of overshooting to the catalyst deterioration temperature.

  On the other hand, FIG. 7 shows the temperature change of the catalytic converter in the case of the present invention, and the super retard combustion is canceled before the internal temperature reaches the catalyst activation temperature T1. At this time, the internal temperature is, for example, the temperature T2 lower than the catalyst activation temperature T1, and after the super retard combustion is released, the temperature further rises from the temperature T2, but does not reach the catalyst deterioration temperature. Further, since the inlet temperature rapidly decreases with the release of the super retard combustion, the temperature difference ΔT between the internal temperature and the inlet temperature when the internal temperature reaches the catalyst activation temperature T1 is shown in FIG. 5 and FIG. Smaller than the case.

  In the above embodiment, the inlet temperature T of the catalytic converter 10 is directly detected by the catalyst inlet temperature sensor 13. However, since the inlet temperature T correlates with the intake air amount of the internal combustion engine, this intake air amount. It is also possible to estimate the inlet temperature T based on.

  Next, FIGS. 8 to 10 show a second embodiment of the present invention. In this embodiment, in order to determine the temperature state of the catalytic converter 10, as shown in FIG. In addition to the catalyst inlet temperature sensor 13 disposed at the inlet portion 10, a catalyst temperature sensor 30 disposed at the center in the longitudinal direction of the monolith ceramic catalyst carrier is provided. Therefore, the internal temperature TC of the catalytic converter 10 is detected together with the catalyst inlet temperature T.

  In this embodiment, the combustion mode is switched while monitoring the temperature state of the catalytic converter 10 by the processing as shown in FIG.

  First, in step 1, the inlet temperature T of the catalytic converter 10 detected by the catalyst inlet temperature sensor 13 and the internal temperature TC of the catalytic converter 10 detected by the catalyst temperature sensor 30 are read. Next, whether or not the catalyst is active in step 2 is determined from, for example, the internal temperature TC at the time of engine start, the cooling water temperature, or the like. If the catalyst is already in an active state as in warm-up restart, the routine proceeds to step 5 and the above-described normal stratified combustion operation or homogeneous combustion operation is performed.

  If the catalyst is in an inactive state as in the cold start, the process proceeds to step 3 to execute the super retard combustion described above. As a result, the exhaust temperature rises rapidly.

  Thereafter, in step 4, it is determined based on the catalyst inlet temperature T and the internal temperature TC whether or not the temperature state of the catalytic converter 10 has reached a predetermined stage before the catalyst is fully activated. Specifically, from the catalyst inlet temperature T and the internal temperature TC, it is repeatedly determined whether the region is in the permission condition or the prohibition condition of the characteristic as shown in FIG. Continue burning. When the prohibited condition region is entered, the routine proceeds from step 4 to step 5, where the super retard combustion is canceled and the routine shifts to normal control. The above-mentioned prohibition condition region is set so that the catalyst temperature that rises after the release of super retard combustion does not excessively overshoot beyond the full activation temperature. As the temperature T is higher, the super retard combustion is released at a stage where the internal temperature TC is lower. Therefore, thermal distortion due to excessive overshoot of the catalyst temperature and extreme temperature gradient is prevented.

  In the above embodiment, the inlet temperature T of the catalytic converter 10 is directly detected by the catalyst inlet temperature sensor 13. However, since the inlet temperature T correlates with the intake air amount of the internal combustion engine, this intake air amount. It is also possible to estimate the inlet temperature T based on.

  In the above embodiment, the internal temperature TC of the catalytic converter 10 is directly detected by the catalyst temperature sensor 30. However, the internal temperature is determined from other parameters, for example, the oxygen storage capacity of the catalytic converter 10 correlated with the catalyst temperature. It is also possible to estimate TC.

  Specifically, as shown in FIGS. 1 and 8, when air-fuel ratio sensors 11 and 12 are provided on the upstream side and downstream side of the catalytic converter 10, respectively, as shown in the upper part of FIG. Air-fuel ratio control is performed so that the air-fuel ratio (exhaust air-fuel ratio) of the internal combustion engine oscillates with an appropriate period and amplitude. For this, a general air-fuel ratio feedback control technique can be used. The air-fuel ratio detected by the upstream air-fuel ratio sensor 11 reflects the change in the air-fuel ratio of the engine as it is with respect to this change in air-fuel ratio. On the other hand, the detected air-fuel ratio of the downstream air-fuel ratio sensor 12 is the same as the signal of the upstream air-fuel ratio sensor 11 because the oxygen storage capacity is low when the catalytic converter 10 is inactive as shown in the lower part of FIG. However, as the temperature of the catalytic converter 10 rises, the oxygen storage capacity increases, and as shown in the figure, the cycle is long and the amplitude is small. Therefore, it can be detected from the relationship between the two that the catalyst has reached the activation start temperature before the complete activation.

BRIEF DESCRIPTION OF THE DRAWINGS The structure explanatory drawing which shows the system structure of the whole internal combustion engine which concerns on this invention. The characteristic view which shows the fuel injection timing and ignition timing of the super retard combustion of this invention. The flowchart which shows the process of the combustion mode switching at the time of starting. The characteristic figure which shows the permission / prohibition area | region of super retard combustion. The characteristic view which shows the change of the catalyst inlet_port | entrance temperature and internal temperature when super retard combustion is continued compared with the case where normal combustion operation is continued. The characteristic view which shows the temperature change at the time of canceling | releasing super retard combustion when internal temperature reaches catalyst activation temperature. The characteristic view which shows the change of the catalyst inlet temperature and internal temperature by this invention. Structure explanatory drawing which shows 2nd Example. The flowchart which shows the process of this 2nd Example. The characteristic view which shows the permission / prohibition area | region in the case of this 2nd Example. The characteristic view which shows the detection air fuel ratio of an upstream air fuel ratio sensor, and the detection air fuel ratio of a downstream air fuel ratio sensor. Explanatory drawing which shows the change of the disturbance in a cylinder in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Combustion chamber 10 ... Catalytic converter 13 ... Catalyst inlet temperature sensor 14 ... Spark plug 15 ... Fuel injection valve 25 ... Control unit 30 ... Catalyst temperature sensor

Claims (11)

  An internal combustion engine that is provided with a fuel injection valve that directly injects fuel into a cylinder and that is provided with an ignition plug, and that requires an early temperature rise of a catalytic converter in an exhaust system in a control device for an in-cylinder direct injection spark ignition internal combustion engine During the cold start, the ignition timing is set after the compression top dead center, and the super-retard combustion is performed before the ignition timing and after the compression top dead center. A control apparatus for an in-cylinder direct injection spark ignition internal combustion engine, wherein the super retard combustion is canceled based on a determination of a temperature state.   2. The control apparatus for a direct injection spark ignition internal combustion engine according to claim 1, wherein the temperature state of the catalytic converter is determined from an inlet temperature of the catalytic converter and a rate of change of the inlet temperature.   3. The control device for a direct injection spark ignition internal combustion engine according to claim 2, wherein the super retard combustion is canceled at a stage where the inlet temperature is lower as the change rate of the inlet temperature is higher.   2. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the temperature state of the catalytic converter is determined from the inlet temperature and the internal temperature of the catalytic converter.   5. The control device for a direct injection spark ignition internal combustion engine according to claim 4, wherein the super retard combustion is canceled at a stage where the internal temperature is lower as the inlet temperature is higher.   6. The control apparatus for a direct injection spark ignition internal combustion engine according to claim 2, wherein the inlet temperature is estimated based on an intake air amount of the internal combustion engine.   6. The control apparatus for a direct injection spark ignition internal combustion engine according to claim 4 or 5, wherein the internal temperature is estimated from an oxygen storage capacity of a catalytic converter correlated with a catalyst temperature.   An upstream air-fuel ratio detecting means provided upstream of the catalytic converter and a downstream air-fuel ratio detecting means provided downstream; a change in detection signal of the upstream air-fuel ratio detecting means and downstream air-fuel ratio detection; 8. The control apparatus for a direct injection spark ignition internal combustion engine according to claim 7, wherein the oxygen storage capacity is estimated from a relationship with a change in a detection signal of the means.   9. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the ignition timing in the super retard combustion is 15 ° to 30 ° CA after compression top dead center.   In the super retard combustion, prior to fuel injection after compression top dead center, fuel injection is further performed during an intake stroke or a compression stroke. A control device for an injection spark ignition internal combustion engine. 11. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the air-fuel ratio in the super retard combustion is a stoichiometric air-fuel ratio or slightly lean.

Images