JP4893499B2 - In-cylinder direct injection spark ignition internal combustion engine control device and control method - Google Patents

Description

  The present invention relates to an in-cylinder direct injection spark ignition internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder and an ignition plug that sparks and ignites an air-fuel mixture in the cylinder. The present invention relates to idle rotation speed control at a cold start where a temperature increase is required.

  As described in Patent Document 1, during idling of an internal combustion engine, so-called idling, in which the throttle opening for adjusting the intake air amount is feedback-controlled so that the engine speed matches the target idle speed. Rotational speed control (hereinafter referred to as ISC control) is performed.

Further, in Patent Document 2 by the present applicant, as a catalyst warm-up method in an in-cylinder direct injection spark ignition internal combustion engine, the ignition timing is set to the compression top dead center ( A technique for performing so-called superretarded combustion in which the fuel injection timing is set after TDC and before the ignition timing is set after TDC is described.
JP 2004-270504 A Japanese Patent Laid-Open No. 2005-214039

  The above super retarded combustion is a technique for increasing the exhaust temperature by combustion in the exhaust passage by reducing the combustion speed by retarding the ignition timing after TDC and reducing the combustion efficiency. Such super retard combustion has a large throttle opening in idling operation to compensate for torque reduction due to a decrease in combustion efficiency, compared to normal combustion in which fuel injection timing and ignition timing are before compression top dead center. It will be a thing.

  In addition, since the exhaust temperature is originally very high in the super retard combustion, if the fuel injection amount or the intake air amount is increased in accordance with an increase in the load on the auxiliary equipment, the combustion amount is further increased and the exhaust temperature is further increased. turn into. For this reason, there is a concern that the temperature of the catalytic converter becomes excessively high, causing thermal damage and deterioration.

  The present invention has been made in view of such problems, and has as its main object to stably and satisfactorily perform idle operation in an in-cylinder direct injection spark ignition internal combustion engine that performs super retard combustion.

The present invention includes a throttle valve that is provided in an intake passage and adjusts an intake air amount into a combustion chamber, a fuel injection valve that injects fuel directly into a cylinder, an ignition plug, and a catalyst that is provided in an exhaust passage. In the cylinder direct injection type spark ignition internal combustion engine control apparatus provided, when the temperature of the catalyst is increased, the temperature of the catalyst provided in the exhaust passage is required to purify the exhaust gas, such as when the internal combustion engine is cold-started. Then, the ignition temperature is set after the compression top dead center by the catalyst temperature raising means to raise the exhaust gas temperature.
Here, during idle operation other than when the temperature of the catalyst is raised, the throttle opening of the throttle valve is adjusted by the first idle rotation speed control means, and the engine rotation speed is feedback controlled to the target idle rotation speed. On the other hand, during the idling operation when the catalyst temperature rises, if the fuel injection amount or the intake air amount is increased according to an increase in the auxiliary load as in the first idle speed control means, the combustion amount of the internal combustion engine is further increased. As a result, the exhaust temperature becomes higher. And the further increase in the amount of combustion at the time of super retard combustion may damage the catalyst. Therefore, during the idling operation at the time of the catalyst temperature rise, the throttle opening is adjusted to the open side in order to feedback control the engine speed to the target idling speed as in the first idling speed control means. Forbidden, when the engine speed is higher than the target idle speed by the second idle speed control means, the throttle opening is adjusted according to the deviation between the engine speed and the target idle speed, When the engine rotational speed is lower than the target idle rotational speed, the ignition timing is adjusted according to the deviation between the engine rotational speed and the target idle rotational speed, and the engine rotational speed is feedback controlled to the target idle rotational speed.

  According to the present invention, the engine speed is feedback-controlled to the target idle speed in response to a drop in the engine speed caused by an increase in auxiliary load or the like during idling when the temperature of the catalyst is raised by super retard combustion. Therefore, without increasing the throttle opening, the engine speed can be returned to the target idle speed by increasing the torque by the advance of the ignition timing, and the increase in the combustion amount due to the increase in the throttle opening is suppressed. Thus, thermal deterioration of the catalyst can be suppressed.

  In the super retard combustion, since the ignition timing has already been greatly retarded, the torque sensitivity is higher than in the case where the ignition timing is advanced in a situation other than the super retard combustion. For this reason, it is possible to quickly return to the target idle rotation speed by the advance of the ignition timing with respect to the drop in the rotation speed due to the auxiliary load or the like, and the response is excellent.

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

FIG. 1 is a system configuration diagram of a direct injection type spark ignition internal combustion engine according to an embodiment of the present invention. In the internal combustion engine 1, a combustion chamber 3 is defined by a cylinder, a cylinder head, and a piston 2. An intake passage 4 is connected to the combustion chamber 3 via an intake valve (not shown), and an exhaust passage 5 is connected via an exhaust valve (not shown). An air flow meter 6 for detecting the amount of intake air is disposed in the intake passage 4, and an electronically controlled throttle valve 7 whose opening degree is controlled via an actuator 8 by a control signal is disposed. 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.
Further, an exhaust gas temperature sensor 13 for detecting the exhaust gas temperature at the inlet side of the catalytic converter 10 is provided along with the upstream air-fuel ratio sensor 11. Furthermore, in the present embodiment, in order to detect the temperature state of the catalytic converter 10, a catalytic temperature sensor 31 disposed at the center in the longitudinal direction of the monolithic ceramic catalyst carrier of the catalytic converter 10 and an outlet portion of the catalytic converter 10. And a catalyst outlet temperature sensor 32 arranged.

  A spark plug 14 for spark-igniting the air-fuel mixture 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 and the regulated fuel pressure 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. In addition, after completion of the early temperature increase of the catalyst 10, the normal stratified combustion operation is performed in the low speed and low load side region, and the normal homogeneous combustion operation is performed in the high speed and high load side region.
In a normal stratified combustion operation, fuel injection is performed at an appropriate time in the compression stroke, and ignition is performed at a time before the compression top dead center. 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. In a 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.

On the other hand, when the temperature of the catalyst is raised, such as during a cold start of the internal combustion engine 1 where an early temperature rise of the catalytic converter 10 is required, super retard combustion is performed so that the exhaust temperature becomes high. In this super retard combustion, the fuel injection timing (at least the last fuel injection timing in the case of multiple injections) and the ignition timing are retarded from the compression top dead center in order to burn the combustion gas in the exhaust passage. Thus, the exhaust gas temperature (also simply referred to as “exhaust temperature”), and thus the catalyst temperature, is raised. Considering raising the temperature of the catalytic converter 10 early, the exhaust temperature rises as the retard amount is increased. However, if the retard amount of the fuel injection timing / ignition timing is increased, the combustion stability is deteriorated. Therefore, the retard amount in which the combustion stability is allowed is set.
At this time, if the fuel injection timing / ignition timing is retarded, the combustion efficiency deteriorates, so that the torque becomes smaller than the normal fuel injection timing / ignition timing. Therefore, this decrease in torque is compensated by increasing the intake air amount to increase the fuel injection amount. The increase in the intake air amount is performed by controlling the electronic control throttle valve 7, and the fuel injection amount is increased in accordance with the increase in the intake air amount.
When the super retard combustion execution condition is satisfied, the actual control is performed as follows. First, a throttle opening is set to compensate for a torque drop when the retard limit is set to allow the combustion stability of the fuel injection timing and the ignition timing. The throttle opening is set by a map of engine speed and load, and the engine speed can be maintained at the target idle speed when the fuel injection timing and the ignition timing are set to the retard limits where the combustion stability is allowed. Opening degree. When the throttle opening is set as described above, the fuel injection timing and the ignition timing are set to the retard limit at which the combustion stability is allowed in consideration of the response delay of the air due to the change in the throttle opening.
The fuel injection timing and ignition timing of this super retard combustion 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, the turbulence generated in the intake stroke and the compression stroke is attenuated after the compression top dead center, but in this embodiment, the high-pressure fuel injection performed during the expansion stroke after the compression top dead center. As a result, a gas flow is generated, and thereby, 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. Since the ignition timing is performed in conjunction with the second fuel injection, the ignition timing is 15 ° to 30 ° ATDC (for example, 20 ° ATDC) similar to that in the first embodiment. In addition, since the total amount of the two fuel injections is the same as the fuel injection amount of the first embodiment, the total air-fuel ratio is the same as in the first embodiment, or the stoichiometric air-fuel ratio or slightly leaner (16 to 17). Degree).

  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 times, 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, the decay of the turbulence due to the fuel spray becomes slower. For this reason, the disturbance due to the first fuel injection remains, and by performing the second fuel injection after the compression top dead center, the disturbance can be strengthened so as to promote the disturbance generated by the first fuel injection. The gas flow can be further strengthened near the 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 ignition, and the flame propagation is promoted, so that the ignition timing is retarded. It is possible to suppress the deterioration of the combustion stability due to, and to perform stable combustion. In particular, by retarding the ignition timing from 15 ° to 30 ° ATDC, it is possible to obtain a sufficient afterburning effect for rapid catalyst temperature rise and HC reduction. 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.

During normal idle operation other than when the catalyst temperature rises without performing super retard combustion, the engine speed detected and calculated by the crank angle sensor 22 and the like is set based on the water temperature, auxiliary load, etc. The throttle opening is mainly feedback-controlled so that That is, the throttle opening is increased or decreased according to the deviation between the engine speed and the target idle speed, and the fuel injection timing and the ignition timing are corrected according to the change in the throttle opening. Alternatively, as described later, the throttle opening and the ignition timing are adjusted according to the deviation between the engine speed and the target idle speed, and the fuel injection amount is corrected according to the throttle opening. For example, when the engine rotational speed becomes smaller than the target idle rotational speed, the target idle rotational speed is controlled by correcting the throttle opening to the open side and increasing the intake air amount. In this embodiment, the normal idle speed control without super retard combustion is referred to as the first ISC control.
On the other hand, at the time of the above-mentioned super retard combustion, that is, at the time of idling operation when the temperature of the catalyst is raised, the exhaust gas temperature is controlled to be extremely higher than that at the time of normal idling operation. If the throttle opening is corrected to the open side and the intake air amount is increased when the rotational speed becomes smaller than the rotational speed, the exhaust temperature originally increased for the early temperature rise of the catalytic converter 10 becomes higher. turn into. Then, the catalytic converter 10 is rapidly heated by the heat of the exhaust gas that has become higher from the upstream side, and there is a concern of thermal distortion of the catalytic converter 10 or an excessive temperature rise.
Therefore, in the present embodiment, the control method of the idle rotation speed control is switched according to whether or not the super retard combustion is performed by the processing of the flowchart shown in FIG. Note that the idle rotation speed control performed during the idling operation when the temperature of the catalyst is raised is referred to as a second ISC control.
FIG. 3 is a flowchart showing the control contents repeatedly executed by the control unit 25 every predetermined period (predetermined crank angle or predetermined time). First, in step S11, it is determined whether an execution condition for idle rotation speed control is satisfied. The execution condition of the idle rotation speed control is satisfied when the idle switch signal is ON and the accelerator pedal is not substantially depressed. The idle switch is a switch that is turned on when the opening degree of the electronic control throttle valve 7 is in the vicinity of the fully closed state. Further, the execution condition of the idle rotation speed control may be established based on a condition that the vehicle speed is substantially 0 (zero), for example. The idle switch signal is not necessarily a physical switch, and may be generated from a detection signal of the accelerator opening sensor 23, for example.

  In step S12, it is determined whether or not a feedback control condition for causing the engine speed to coincide with the target idle speed is satisfied. This feedback condition includes whether the sensors and actuators used for feedback control are normal and whether the deviation between the target idle speed and the engine speed is within a predetermined reference range.

If both the idle condition and the feedback condition are satisfied, the process proceeds to step S13 to determine whether the above-described super retard combustion is performed. When the super retard combustion is not executed, the process proceeds to step S14, and the first ISC control described above is performed.
The first ISC control will be described with reference to FIG. FIG. 4 is a time chart showing a control state of the ignition timing and the throttle opening from the engine start to the idle operation. First, when the starter switch is turned on (T0), cranking by the starter is started and the engine is completely exploded (T2). In the period (T2 to T3) in which the engine speed rNe is overshooting after the complete explosion, the throttle opening is gradually decreased in order to decrease the engine speed rNe toward the target idle speed INe. . When the engine speed rNe decreases to near the target idle speed tINe (T3), the throttle opening and the ignition timing are feedback-controlled so that the engine speed rNe matches the target idle speed tINe. As is well known, this feedback control is performed using, for example, PI control. The control of the fuel injection amount is increased according to the increase of the intake air amount when the throttle opening is controlled to the open side.
Then, when an auxiliary machine load such as an alternator is applied at a time T4 when a predetermined period has elapsed from the start of the engine, the engine speed rNe decreases. Then, in order to feed back the reduced engine speed rNE to the target idle speed tINe, the intake air amount is increased by controlling the throttle opening to the open side, and the ignition timing is temporarily advanced. Increase the torque with. Thus, in the first ISC control executed when the super retard combustion is not executed, feedback control to the target idle speed is performed by controlling the ignition timing, the throttle opening, and the fuel injection amount.
Here, the description returns to the flowchart of FIG. In step S13, for example, when the catalytic converter 10 is to be activated quickly, for example, at the time of cold start, that is, when super retard combustion is executed, the process proceeds to step S15, and second ISC control different from the first ISC control is performed. Is called.

Here, the second ISC control will be described with reference to the time chart of FIG. When the starter switch is turned on (T0), cranking by the starter is started, and an initial explosion is performed by stratified combustion with a single compression stroke injection. At timing T1, stratified combustion is switched to super retarded combustion. And when this super retard combustion is performed, 2nd ISC control is performed.
In the second ISC control in the present embodiment, the throttle opening is set to the target idle speed from the opening set at the time of cranking to the engine speed rNe during the super retard combustion, as in the periods T2 to T3 shown in FIG. It gradually decreases toward the opening degree that maintains the speed tINe. During this time, the intake air amount is reduced as the throttle opening decreases. The throttle opening after time T3 when the engine rotational speed rNe decreases to near the target idle rotational speed rINe is set by a map at the time of super retard combustion. The throttle opening at this time is an opening that compensates for torque reduction due to super retard combustion, and is set to a larger opening than the throttle opening set in the first ISC control. However, during idle operation when the catalyst temperature rises, feedback control is performed so that the engine speed is adjusted toward the target idle speed mainly by adjusting the ignition timing. For example, after an auxiliary machine load is applied (T4- ), When the engine speed rNe is lower than the target idle speed tINe, it is prohibited to control the throttle opening to the open side in order to compensate for the decrease in the engine speed due to the input of the additional load. ing.
As described above, the throttle opening at the time of super retard combustion is set by the engine speed and load map, and the engine speed is set when the fuel injection timing and ignition timing are set to the retard limit where the combustion stability is allowed. This is the opening degree at which the speed rNe can be maintained at the target idle rotation speed tINe.
With respect to the throttle opening set in this way, the second ISC control prohibits correction to the open side as in the first ISC control even if the engine speed rNe decreases with the input of the auxiliary machine load. Then, by advancing the set ignition timing in the super retard combustion, the engine speed rNe that has fallen due to the auxiliary load is returned to the target idle speed tINe.
In super retard combustion, since fuel injection is performed immediately before the ignition timing in order to collect a rich fuel mixture around the spark plug, the fuel injection timing is advanced according to the advance of the ignition timing. Specifically, the fuel injection timing is advanced (or retarded) in synchronization with the advance (or retard) of the ignition timing so as to ensure a substantially constant period α between the fuel injection timing and the ignition timing. )

  FIG. 6 shows a state where the second ISC control is performed at the time of super retard combustion, as in FIG. 5, and the auxiliary load is larger than the situation of FIG. 5. In this case, the decrease in the engine speed rNe due to the load on the auxiliary machine is large, and the advance amount of the ignition timing for making up for this increases. Then, the super retard combustion is stopped / released at a time T5 when the ignition timing is a preset value and reaches a limit value on the advance side where stable super retard combustion can be secured. Then, the super-retard combustion is switched to the homogeneous combustion in which fuel is injected in the intake stroke, and the second ISC control is switched to the first ISC control.

  As described above, according to the present embodiment, super-retard combustion is performed at the time of cold start of an internal combustion engine that requires an early temperature increase of the catalytic converter 10, thereby realizing early activation of the catalyst and HC reduction by afterburning. can do. When super retard combustion is not performed, the engine speed rNe is controlled by performing the first ISC control for feedback control of the throttle opening and the ignition timing so that the engine speed rNe matches the target idle speed tINe. Can be accurately maintained at the target idle rotation speed tINe.

On the other hand, when the super retard combustion is being performed, the exhaust gas temperature is raised to raise the temperature of the catalytic converter 10 early. The retard amount of the fuel injection timing / ignition timing at this time is set to a limit retard amount that allows combustion stability. The retard amount may be set in consideration of the combustion stability and / or the lifetime due to thermal degradation of the catalytic converter 10.
When the engine rotation speed rNe is reduced due to the application of an auxiliary machine load or the like during execution of such super retard combustion, if the intake air amount is increased, the fuel injection amount is increased accordingly. The amount of heat due to the combustion increases. As described above, the super retard combustion is a thermally harsh environment for the catalytic converter 10. Therefore, if the amount of heat due to combustion increases due to the auxiliary load, there is a concern that thermal damage or deterioration may occur.
Therefore, in the present embodiment, when super retard combustion is performed, the second ISC control is performed instead of the first ISC control. In the second ISC control, when the engine rotational speed is lower than the target idle rotational speed, the torque is increased by the advance angle of the ignition timing and the advance angle of the fuel injection timing accompanying this, so the first ISC that increases the intake air amount Compared to control, it is possible to suppress an increase in the amount of heat due to combustion and increase the torque, so that it is possible to suppress excessive temperature rise of the catalytic converter 10.
In super retarded combustion, the ignition timing is already substantially retarded from the MBT (minimum advance for best torque) point, so that the ignition timing is advanced compared to normal combustion. The torque improvement effect by is high. For this reason, it is possible to quickly return the engine speed drop to the target idle speed by the advance of the ignition timing without controlling the throttle opening.
In the super retard combustion, since the ignition timing is already largely retarded, it is difficult to further retard the ignition timing, and the torque sensitivity due to the retarded ignition timing is low. Therefore, in the second ISC control, when the engine speed rNe is decreased toward the target idle speed tINe, the intake air amount is decreased by the throttle opening as in the first ISC control. On the other hand, when the engine speed rNe is increased toward the target idle speed tINe, the ignition timing is advanced and the fuel injection timing is advanced without increasing the intake air amount. That is, in the second ISC control, when the engine speed is higher than the target idle speed, the throttle opening is adjusted to the lower side or the closed side according to the deviation between the engine speed and the target idle speed, and the engine When the rotational speed is lower than the target idle rotational speed, the throttle opening is prohibited from increasing, and the ignition timing is adjusted to the advance side according to the deviation between the engine rotational speed and the target idle rotational speed. Yes. Thereby, even during the super retard combustion, the thermal influence on the catalytic converter 10 can be suppressed, and the control to the target idle rotation speed tINe can be performed with good responsiveness.

As described above, the present invention has been described based on specific embodiments. However, the present invention is not limited to the above embodiments, and includes various modifications and changes without departing from the spirit of the present invention. .
For example, in the second ISC control, only the ignition timing and the fuel injection timing may be controlled regardless of the increase / decrease in the engine speed rNe. Further, in a hybrid vehicle or the like that uses both an engine and a motor, a decrease in torque at the time of super retard combustion may be compensated by torque from the motor.

BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing which shows the system configuration | structure of the whole internal combustion engine which concerns on one Embodiment of this invention. The characteristic view which shows the fuel injection timing and ignition timing of the super retard combustion which concerns on the said embodiment. The flowchart which shows the switching process of ISC control which concerns on the said embodiment. The time chart which shows an example at the time of engine starting in which the 1st ISC control which concerns on the said embodiment is performed. The time chart which shows an example at the time of engine starting in which 2nd ISC control which concerns on the said embodiment is performed. The time chart which shows the other example at the time of engine starting in which the 2nd ISC control which concerns on the said embodiment is performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 3 ... Combustion chamber 10 ... Catalytic converter 13 ... Exhaust temperature sensor 14 ... Spark plug 15 ... Fuel injection valve 25 ... Control unit

Claims (6)

A cylinder provided with a throttle valve provided in the intake passage for adjusting the amount of intake air into the combustion chamber, a fuel injection valve for directly injecting fuel into the cylinder, a spark plug, and a catalyst provided in the exhaust passage In a control device for a direct injection spark ignition internal combustion engine,
Catalyst temperature raising means for setting the ignition timing after the compression top dead center and raising the exhaust gas temperature when raising the temperature of the catalyst required to raise the temperature of the catalyst;
First idle rotation speed control means for adjusting the throttle opening of the throttle valve and performing feedback control of the engine rotation speed to a target idle rotation speed during idle operation other than when the catalyst is heated;
During idle operation when the catalyst Atsushi Nobori, and prohibits the opening of the side adjustment of the throttle valve, and a second idle speed control means for feedback controlling the engine speed to the target idle rotational speed,
Equipped with a,
The second idle speed control means adjusts the throttle opening in accordance with the deviation between the engine speed and the target idle speed when the engine speed is higher than the target idle speed, and the engine speed A control device for a direct injection spark ignition internal combustion engine, wherein the ignition timing is adjusted in accordance with the deviation between the engine speed and the target idle speed when the engine speed is lower than the target idle speed . The catalyst temperature raising means sets the fuel injection timing after compression top dead center,
2. The control device for a direct injection spark-ignition internal combustion engine according to claim 1, wherein the second idle speed control means advances the fuel injection timing in accordance with the advance angle of the ignition timing. .   3. The cylinder according to claim 1, wherein the second idle rotation speed control means limits the advance amount of the ignition timing based on combustion stability when the temperature of the catalyst is increased. Control device for internal direct injection spark ignition internal combustion engine.   The second idle speed control means stops the rise of the exhaust temperature by the catalyst temperature raising means when the advance amount of the ignition timing exceeds a limit value set based on the combustion stability. The control apparatus for a direct injection type spark ignition internal combustion engine according to claim 3. A cylinder provided with a throttle valve provided in the intake passage for adjusting the amount of intake air into the combustion chamber, a fuel injection valve for directly injecting fuel into the cylinder, a spark plug, and a catalyst provided in the exhaust passage In a control method for a direct injection spark ignition internal combustion engine,
When the temperature of the catalyst is required to rise, the ignition timing is set after compression top dead center to raise the exhaust temperature,
During idle operation other than during the catalyst temperature rise, while adjusting the throttle opening so that the engine speed matches the target idle speed,
During idle operation at the time of catalyst temperature rise , adjustment on the opening side of the throttle valve is prohibited , and the engine speed is higher than the target idle speed so that the engine speed matches the target idle speed. When the engine speed is high, the throttle opening is adjusted according to the deviation between the engine speed and the target idle speed, and when the engine speed is lower than the target idle speed, the engine speed and the target idle speed A control method for an in-cylinder direct injection spark ignition internal combustion engine, characterized in that the ignition timing is adjusted in accordance with the deviation of . 6. The direct in-cylinder operation according to claim 5 , wherein the throttle opening is set larger during idle operation when the catalyst temperature is higher than during idle operation when the catalyst temperature is not higher. A control method for an injection spark ignition internal combustion engine.

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