JP2008180184A - Control device for cylinder injection type spark ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a cylinder injection type spark ignition internal combustion engine capable of controlling idling speed with corresponding to load fluctuation or the like almost without dropping warming up action of exhaust gas on an exhaust emission control catalyst by minimizing drop of exhaust gas temperature under idling condition during catalyst warming up. <P>SOLUTION: When it is judged that the exhaust emission control catalyst is not warmed up during idling of an internal combustion engine, ignition timing is retarded than base advancing value and exhaust gas temperature is raised to warm up the catalyst. When load fluctuates and rotation speed fluctuates during warming up of the catalyst, target suction air quantity is calculated from difference between target idling speed and actual idling speed and intake air quantity is changed by an intake air quantity adjusting means. Output of the internal combustion engine is adjusted by changing ignition timing together. When load fluctuation is large, ignition timing is also changed together. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a direct injection spark ignition internal combustion engine provided with a fuel injection valve that injects fuel directly into a combustion chamber.

  There is a demand for reducing exhaust gas substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in automobile exhaust gas. The exhaust gas substances have been reduced by utilizing the purification action by the catalyst. However, the action of the catalyst becomes effective after the temperature of the catalyst becomes higher than a certain level and the catalyst is activated. When the catalyst is cooled immediately after the internal combustion engine is started, the exhaust gas substance is discharged as it is. Therefore, immediately after start-up, the internal combustion engine is controlled such that the ignition timing is retarded more than usual and the exhaust gas temperature is raised to promote warming up of the catalyst and to activate the catalyst at an early stage.

  Further, in a cylinder injection type spark ignition internal combustion engine provided with a fuel injection valve for directly injecting fuel into the combustion chamber, the ignition timing is obtained by injecting the fuel in a state where the combustible mixture is unevenly distributed around the ignition plug. Can be further retarded. Therefore, the in-cylinder spark-ignition internal combustion engine can raise the exhaust gas temperature more than the internal combustion engine that injects fuel at the intake port, thereby further reducing the time until activation of the catalyst and reducing exhaust gas substances. (Patent Document 1).

  Conventionally, with respect to rotational speed control during idling in a direct injection spark ignition internal combustion engine, as shown in Patent Document 2, rotational speed control is performed based on not only intake air amount correction means but also fuel injection amount correction means. Even when the speed changes rapidly, the idle speed can be quickly controlled to an appropriate speed by correcting the fuel injection amount, and the idling operation can be stabilized.

  Also, in an in-cylinder spark-ignition internal combustion engine, during idle operation in which fuel is injected during the intake stroke to form a homogeneous mixture, control is performed to correct the ignition timing so that the idle rotation speed matches the target rotation speed. In the idling operation in which the fuel is injected in the compression stroke to form the stratified mixture, the control device for the internal combustion engine which controls the fuel injection amount or the air-fuel ratio so as to match the idle rotation speed with the target rotation speed (Patent Document 3).

  Further, in the direct injection internal combustion engine, a rotation speed detecting means for detecting the actual engine speed of the internal combustion engine is provided, and the idle stabilization control means performs fuel according to the difference between the target idle engine speed and the actual engine speed. It has been proposed to stabilize the idling operation at the target idling engine speed and improve the driving feeling by controlling the injection timing (Patent Document 4).

JP 2000-38945 A Japanese Patent No. 3478318 Japanese Patent No. 3700328 Japanese Patent Laid-Open No. 9-120101

  As described above, the rotation control in the idling state of the spark ignition internal combustion engine includes the one that maintains the idle rotation speed by controlling the intake air amount corresponding to the fluctuation of the engine load, and the air-fuel ratio by the fuel injection amount. Various idling controls have been proposed for maintaining the idling speed, such as maintaining the idling speed by controlling, and maintaining the idling speed by controlling the ignition timing. However, no idling control has been proposed to maintain the engine speed in consideration of catalyst warm-up in the idling state during catalyst warm-up.

  In the idling state of the in-cylinder injection spark ignition internal combustion engine, when the ignition delay is performed for warming up the catalyst, the ignition delay amount is larger than that of the intake port injection internal combustion engine. The opening is large and the amount of intake air is large. Therefore, the responsiveness of the air amount increase / decrease due to the operation of the intake air amount adjusting means such as the throttle valve is further delayed, and the controllability for maintaining the idle speed is also deteriorated.

  In addition, when adjusting the intake air amount by changing the opening of the throttle valve in response to load fluctuations, the intake air amount adjusted by the throttle valve is introduced into the combustion chamber through the collector and the intake pipe. It takes time to set the engine speed to the target engine speed, and it cannot cope with a sudden load fluctuation.

  For this reason, conventionally, when there is a sudden load change in the idling state during catalyst warm-up, the ignition timing is changed. In other words, when the load increases, the ignition timing is first advanced to prevent the engine rotation from dropping, and after the intake air amount corresponding to the increase in load is increased, the ignition timing is returned to the original retard (retard) timing. It will be. However, because of the structure of the internal combustion engine, the change in the amount of air taken into the cylinder is delayed, and during this time, the ignition timing is advanced from the original ignition timing, and the warm-up performance of the catalyst deteriorates.

  Therefore, the present inventors conducted various experiments in order to verify the combustion state of the internal combustion engine in the idling state in the direct injection spark ignition internal combustion engine, and analyzed the behavior thereof.

  FIG. 6A shows the air-fuel ratio and the exhaust gas hydrocarbon (HC) when the air-fuel ratio (A / F) is changed while retarding the ignition timing and setting the combustion to the expansion stroke. It shows the relationship between components and exhaust gas temperature. In this combustion mode, the combustion reaction in the cylinder is slowed by delaying the ignition timing, and surplus oxygen is present in the exhaust gas by making the air-fuel ratio leaner than the stoichiometric, so after the unburned fuel after the exhaust pipe. A burning reaction occurs and the exhaust temperature rises. However, when the air-fuel ratio is lean, the exhaust temperature decreases as the air-fuel ratio becomes leaner, and the amount of unburned hydrocarbon (HC) that represents unburned fuel components increases. FIG. 6B shows the amount of smoke (SOOT) discharged at that time. When the air-fuel ratio is richer than 16, smoke emissions increase rapidly. Smoke is produced in a steamed state where the fuel component is oxygen-deficient, so that the richer the fuel, the easier it is to discharge. From the above, in order to warm up the three-way catalyst at an early stage, it is necessary to make the air-fuel ratio as rich as possible on the lean side of the stoichiometry, but it is necessary to make the smoke emission amount below the reference value. An appropriate air / fuel ratio must be set to satisfy. For this reason, in the idling state where the catalyst is warmed up, it is impossible to adjust the load variation with the air-fuel ratio.

  FIG. 7 shows the relationship between the ignition timing, the exhaust temperature, and the indicated mean effective pressure when the ignition timing is changed when the ignition timing is retarded and set to the expansion stroke for combustion. When the ignition timing is retarded, the indicated mean effective pressure decreases and the exhaust temperature rises. It is considered that if the ignition timing is retarded, the combustion becomes slow and the effective work decreases. Therefore, in the idling state in which the catalyst is warmed up, the engine output can be adjusted by changing the ignition timing with respect to the fluctuation of the external load, and the engine speed can be maintained. However, if the ignition timing is advanced, the exhaust temperature will decrease, so maintaining the engine speed by changing the ignition timing, especially when the external load increases, reduces the warming-up action of the exhaust gas on the catalyst. Become.

  FIG. 8 shows the relationship between the fuel injection timing, the exhaust temperature, and the indicated mean effective pressure when the fuel injection timing is changed when the ignition timing is retarded and the combustion is set in the expansion stroke. When fuel injection is performed in the compression stroke, the indicated mean effective pressure increases as the injection timing is retarded, but the exhaust temperature hardly changes. If the injection timing is retarded, the time until the ignition timing is shortened, and vaporized fuel tends to be unevenly distributed around the spark plug. For this reason, it is considered that the indicated mean effective pressure increases because the effective rate of work increases as the combustion speed increases. Moreover, even if the fuel injection timing is changed to the advance side or the retard side to change the indicated mean effective pressure, the exhaust temperature hardly changes. Therefore, in an in-cylinder injection spark ignition internal combustion engine, it is effective to control the engine speed by adjusting the engine torque by adjusting the fuel injection timing in the idling state where the catalyst is warmed up. I knew.

  The present invention has been made on the basis of the above-described experiments and knowledge based on the consideration thereof. In the idling state during catalyst warm-up, the exhaust gas temperature is minimized and the exhaust gas purification catalyst is warmed. It is an object of the present invention to provide a control device for a direct injection spark ignition internal combustion engine capable of quickly controlling the idling rotational speed corresponding to load fluctuation or the like with almost no reduction in mechanical action.

  In order to achieve the above object, a control device for an in-cylinder spark ignition internal combustion engine according to the present invention includes a fuel injection valve that directly injects fuel into a combustion chamber, an exhaust gas purification catalyst in an exhaust gas passage, and an internal combustion engine. , A means for determining a warm-up state of the exhaust gas purifying catalyst, and a means for determining an idle state, wherein the control device is configured such that the means for determining the idle state is an idling state of the internal combustion engine. When the means for determining the warm-up state of the exhaust gas purification catalyst determines that the exhaust gas purification catalyst is not warmed up, the ignition timing is retarded from the basic advance value. In addition, the idle speed is controlled by changing at least the fuel injection timing.

  In the present invention, when the exhaust purification catalyst is not warmed up, the ignition timing is retarded from the basic advance value, so that the exhaust gas purification catalyst is warmed up by increasing the exhaust temperature at an early stage. The purification catalyst can be activated, and the idle speed at the time of load fluctuation or the like is controlled by changing at least the fuel injection timing, so that the exhaust temperature decrease is minimized, and the exhaust gas to the exhaust gas purification catalyst is reduced. The idling speed can be quickly controlled with almost no decrease in warm-up action.

  Specifically, the control device for a direct injection spark ignition internal combustion engine according to the present invention changes the fuel injection timing in the range of the compression stroke, and also detects the actual idle speed detected by the speed detection means of the internal combustion engine. When the engine speed falls below the target idle speed, the fuel injection timing is retarded, and when the actual speed exceeds the target speed, the fuel injection timing is advanced.

  In addition, the control device for a direct injection spark ignition internal combustion engine according to the present invention is characterized in that at least the fuel injection timing and the ignition timing are changed. When the idle speed cannot be controlled to the target idle speed, the actual idle speed can be controlled to the target idle speed by changing the ignition timing.

  Specifically, the control device for a direct injection spark ignition internal combustion engine according to the present invention advances the ignition timing when the actual idle speed falls below the target idle speed, and the actual speed is the target speed. Is exceeded, the ignition timing is retarded, and the amount of change in the fuel injection timing and the ignition timing is determined and changed according to the difference between the actual idle speed and the target idle speed.

  More specifically, the control device for a direct injection spark ignition internal combustion engine according to the present invention is configured such that when the difference between the actual idle speed and the target idle speed is small, the amount of change in the fuel injection timing is greater than the amount of change in the ignition timing. When the difference between the actual idle speed and the target idle speed is large, the amount of change in the ignition timing is made larger than the amount of change in the fuel injection timing.

  Further, the control device for a direct injection spark ignition internal combustion engine according to the present invention includes a fuel injection valve that directly injects fuel into the combustion chamber, an exhaust gas purification catalyst in the exhaust gas passage, and a rotational speed detection means of the internal combustion engine. And an intake air amount measuring means, a means for determining an idle state, and a means for determining a warm-up state of the exhaust gas purifying catalyst, the actual idle speed detected by the rotational speed detection means of the internal combustion engine and the target idle speed The target intake air amount is calculated from the difference from the rotational speed, the intake air amount is changed by the intake air amount adjusting means, and the control device determines that the internal combustion engine is in an idle state by the means for determining the idle state And when the means for determining the warm-up state of the exhaust gas purification catalyst determines that the exhaust gas purification catalyst is not warmed up, the ignition timing is set to a value retarded from the basic advance value, Adjusting the intake air amount With changing the amount of intake air by the stage it is characterized by controlling the idle speed by changing from the basic value of at least the fuel injection timing.

  In the present invention, when the exhaust gas purification catalyst is not warmed up, the ignition timing is retarded from the basic advance value. Therefore, the exhaust gas purification catalyst is warmed up at a high temperature to accelerate the exhaust gas early. The gas purification catalyst can be activated, and the idle speed at the time of load fluctuation or the like is controlled by changing at least the fuel injection timing. It can be covered by control of the idling speed by changing the injection timing, and the idling speed can be quickly increased with minimal decrease in exhaust temperature and almost no degradation of the exhaust gas warm-up action on the exhaust gas purification catalyst. Can be controlled.

  Furthermore, the control device for a direct injection spark ignition internal combustion engine according to the present invention sets the fuel injection timing to a basic value as the difference between the actual intake air amount measured by the intake air amount measuring means and the target intake air amount becomes smaller. It is characterized in that the idling speed can be quickly controlled by changing the fuel injection timing even when a load fluctuation or the like occurs again.

  Specifically, the control device for a direct injection spark ignition internal combustion engine according to the present invention changes the fuel injection timing in the range of the compression stroke, and the actual idle speed falls below the target idle speed. The intake air amount adjustment means increases the intake air amount, retards the fuel injection timing, and if the actual rotation speed exceeds the target rotation speed, the intake air amount adjustment means decreases the intake air amount and fuel injection. Advance the time.

  The control device for a cylinder injection spark ignition internal combustion engine according to the present invention is characterized in that the intake air amount is changed by the intake air amount adjusting means, and at least the fuel injection timing and the ignition timing are changed. When the actual idle speed cannot be controlled to the target idle speed simply by changing the fuel injection timing, the ignition timing is also changed, and the idle speed control delay due to the change in the intake air amount is reduced. Further, it can be covered by controlling the idling speed by changing the fuel injection timing and the ignition timing.

  Furthermore, the control device for a direct injection spark ignition internal combustion engine according to the present invention returns the ignition timing to a value retarded from the basic advance value as the difference between the target intake air amount and the actual intake air amount decreases. As the actual intake air amount changes and the target torque is obtained, the ignition timing is returned to a value retarded from the basic advance value, so the exhaust temperature is raised and the catalyst is warmed up. You can expedite.

  Specifically, the control device for a direct injection spark ignition internal combustion engine according to the present invention advances the ignition timing when the actual idle speed falls below the target idle speed, and the actual speed is the target speed. If it exceeds, the ignition timing is retarded.

  A control device for a cylinder injection spark ignition internal combustion engine according to the present invention is characterized by determining and changing a change amount of a fuel injection timing and an ignition timing based on a difference between an actual idle speed and a target idle speed. If the difference between the actual idle speed and the target idle speed is small, the change amount of the fuel injection timing is changed to be larger than the change amount of the ignition timing, and the difference between the actual idle speed and the target idle speed is large. In this case, the change amount of the ignition timing is changed by decreasing the change amount of the fuel injection timing.

  The present invention controls the idle speed by giving priority to the amount of change in the fuel injection timing over the amount of change in the ignition timing, and reduces catalyst temperature reduction to promote catalyst warm-up. It can be controlled quickly.

  In the present invention, when the exhaust gas purification catalyst is not warmed up, the ignition timing is retarded from the basic advance value. Therefore, the exhaust gas temperature is increased to promote warming up of the exhaust gas purification catalyst at an early stage. The exhaust gas purification catalyst can be activated, and the idle speed at the time of load fluctuation or the like is controlled by changing at least the fuel injection timing. It is possible to quickly control the idling speed without substantially reducing the gas warm-up action.

  Embodiments of a control device for a direct injection spark ignition internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 1 shows the basic configuration of a direct injection spark ignition internal combustion engine and its control device according to the present invention. In the figure, the engine 1 is provided with a piston 2, an intake valve 3, and an exhaust valve 4. The intake air passes through the air flow meter (AFM) 20 and enters the throttle valve 19, and is supplied to the combustion chamber 21 of the engine 1 through the intake pipe 10 and the intake valve 3 from the collector 15 which is a branching portion. The fuel is injected and supplied from the fuel injection valve 5 to the combustion chamber 21 of the engine 1 and ignited by the ignition coil 7 and the spark plug 6. The exhaust gas after combustion is discharged to the exhaust pipe 11 through the exhaust valve 4. The exhaust pipe 11 is provided with a three-way catalyst 12 for purifying exhaust gas. The ECU (engine control unit) 9 includes a signal from the crank angle sensor 16 of the engine 1, an air amount signal from the AFM 20, a signal from the oxygen sensor 13 for detecting the oxygen concentration in the exhaust gas, and an accelerator opening of the accelerator opening sensor 22. Etc. are input. The ECU 9 calculates the required torque to the engine from the signal of the accelerator opening sensor 22 and determines the idle state. In the ECU 9, the three-way catalyst 12 is warmed up based on the rotation speed detection means for calculating the engine rotation speed from the signal of the crank angle sensor 16, the water temperature of the internal combustion engine obtained from the water temperature sensor 8, the elapsed time after the engine start, and the like. Means are provided for determining whether or not the state is correct. Further, the ECU 9 calculates the intake air amount necessary for the engine 1, outputs an opening signal corresponding to the intake air amount to the throttle valve 19, calculates the fuel amount corresponding to the intake air amount, and injects the fuel into the fuel injection valve 5. A signal is output and an ignition signal is output to the spark plug 6.

  When the air-fuel ratio of the exhaust gas discharged through the exhaust pipe 11 is in the vicinity of the stoichiometric air-fuel ratio, the three-way catalyst 12 includes carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) contained in the exhaust gas. Can be purified at the same time. For this reason, the ECU 9 determines the exhaust air-fuel ratio from the signal of the oxygen sensor 13 and feedback-controls the amount of fuel injected from the fuel injection valve 5, thereby maintaining the air-fuel ratio of the exhaust gas near the theoretical air-fuel ratio. However, the purification effect of the three-way catalyst 12 becomes effective after the temperature becomes a certain level or higher (for example, 300 ° C. or more), and the substances contained in the exhaust gas when the three-way catalyst 12 is cooled immediately after the engine is started. Is discharged without being purified by the three-way catalyst 12.

  If the ECU 9 determines that the three-way catalyst 12 is inactive immediately after the engine is started, the ignition timing is retarded from normal, for example, set to an expansion stroke, and the exhaust temperature is raised to warm the three-way catalyst 12. The engine control for activating the three-way catalyst 12 at an early stage is performed. In the in-cylinder direct injection type engine provided with the fuel injection valve 5 that directly injects fuel into the combustion chamber 21, the combustible air-fuel mixture can be unevenly distributed around the spark plug 6, so that fuel is injected through the intake pipe 10. The exhaust temperature can be raised by retarding the ignition timing as compared with the engine.

  On the other hand, when the ECU 9 determines that the engine is in an idle state based on a signal from the accelerator opening sensor 22, the ECU 9 keeps the engine speed that is the actual idle speed at the target engine speed that is the target idle speed. The amount of intake air necessary for the operation is calculated, and the opening of the throttle valve 19 is changed. The intake air amount adjusted by the throttle valve 19 is introduced into the combustion chamber 21 through the collector 15 and the intake pipe 10, so that an air amount necessary for the engine load can be obtained. However, in the control of the engine speed by adjusting the intake air amount by the throttle valve 19, it takes time until the engine speed reaches the target engine speed. Therefore, for sudden load fluctuations, the engine output is adjusted by changing the fuel injection timing together with the adjustment of the throttle valve 19 to stabilize the engine speed. If the target engine speed cannot be achieved simply by changing the fuel injection timing due to large load fluctuations, the engine output can be adjusted by changing the ignition timing in addition to the fuel injection timing to stabilize the engine speed. ing.

  FIG. 2 shows a flowchart for performing idle control in the control apparatus for a direct injection spark ignition internal combustion engine of the present invention. In step 90, the ECU 9 determines whether or not the engine is in an idle state based on a signal from an accelerator opening degree sensor 22 that is a means for determining an idle state. In step 91, means for determining whether the three-way catalyst 12 is in a warmed-up state determines whether the three-way catalyst 12 is in a warmed-up state, and the three-way catalyst 12 is warmed up. When it is determined that the warm-up is not necessary, the routine proceeds to step 93 where normal idle control is performed. When it is determined that the warm-up is necessary, the catalyst warm-up idle control is performed at step 92. In this combustion method, fuel is injected at least in the compression stroke, and the ignition timing is set to the expansion stroke.

  FIG. 3 shows a flowchart of the catalyst warm-up idle control (step 91 in FIG. 2) in the control apparatus for a direct injection spark ignition internal combustion engine of the present invention. In step 101, if the ECU 9 recognizes the difference between the actual engine speed and the target engine speed, or recognizes an external load by an auxiliary device such as an air conditioner or a power steering, the process proceeds to step 102, where the speed difference, load A target torque corresponding to the fluctuation is calculated, a target air amount corresponding to the target torque is calculated, and the opening degree of the throttle valve 19 is changed to correct the intake air amount. In step 103, it is determined whether the intake air amount detected by the AFM 20 matches the target air amount. If not, the process proceeds to step 104. In step 104, it is determined whether the difference between the actual engine speed and the target engine speed, or the magnitude of the load fluctuation is larger than the reference value. If it is larger than the reference value, the fuel injection timing is determined in step 105. The delay in the air response is compensated by controlling the engine speed by the correction and the correction of the ignition timing. If the difference between the actual engine speed and the target engine speed or the magnitude of the load fluctuation is smaller than the reference value in step 104, the routine proceeds to step 106, where only the injection timing is corrected and the engine speed is corrected. The delay of the air response is compensated by controlling.

FIG. 4 shows the relationship between the fuel injection timing, ignition timing, and engine torque level in the combustion establishment range during catalyst warm-up. The combustion establishment range is a region that satisfies all engine performance such as combustion stability and exhaust gas emission components. Since it is necessary to make the exhaust gas temperature as high as possible while the catalyst is warming up, a reference ignition timing FB is set in which the ignition timing is retarded as much as possible with a margin within a range where combustion is established. Now, when the engine is, when the reference ignition timing FB, is driven by the injection timing T ₁ is a combustion state of point A which outputs a torque 1, it becomes necessary to output the torque 2 due to load fluctuation or the like , timing morphism fuel injection timing from the injection timing T ₁ is corrected to T ₂ to output a torque 2 (combustion state of point B) by controlling the engine speed (correction method of the injection timing in the arrow a in FIG. 4 Show.) That is, it is a case where it is determined in step 104 of FIG. 3 that the difference between the actual engine speed and the target engine speed or the load fluctuation is equal to or less than the reference value, and the fuel injection timing correction (step 106) is performed. This correction does not lower the exhaust gas temperature, so the catalyst warm-up is promoted.

However, if the load fluctuation is large and it is necessary to output the engine output up to torque 3, the required torque cannot be obtained only by correcting the injection timing, so the ignition timing is set to the ignition timing F1. is corrected, (combustion state at point C) the fuel injection timing is corrected so that the injection timing T _3, is controlled so that the torque 3 required output. That is, it is a case where it is determined in step 104 of FIG. 3 that the difference between the actual engine speed and the target engine speed or the load fluctuation is greater than or equal to the reference value, and the ignition timing correction (step 105) together with the fuel injection timing I do. When there are a plurality of combinations of injection timings and ignition timings capable of outputting the same torque, as indicated by arrows b and c, in order to maintain the exhaust temperature as high as possible so as not to deteriorate the warm-up action of the exhaust gas with respect to the three-way catalyst 12 Selects a combination of the injection timing and the ignition timing indicated by the arrow b that can retard the ignition timing as much as possible.

  If the difference between the actual engine speed and the target engine speed or the load fluctuation slightly exceeds the reference value, priority will be given to control based on changes in the fuel injection timing, and the amount of change in the fuel injection timing will be greater than the amount of change in the ignition timing. When the difference is made and the difference between the actual idle speed and the target idle speed or the load fluctuation greatly exceeds the reference value, the change amount of the ignition timing is changed by making the change amount of the fuel injection timing larger.

  Also, when the actual engine speed increases from the target engine speed or when the external load decreases, the fuel is the same as when the actual engine speed decreases from the target engine speed or the external load increases. Priority is given to changes in injection timing.

  In this embodiment, when the difference between the actual engine speed and the target engine speed or a load fluctuation occurs, the engine speed is controlled with priority given to the correction of the fuel injection timing. Thus, it is possible to minimize the change in the exhaust temperature and stabilize the engine speed in the idle state without deteriorating the warm-up of the three-way catalyst 12.

  As described above, while there is a response delay in the intake air amount, the engine output is adjusted by changing the injection timing and ignition timing so that the ignition timing is not advanced as much as possible, and control is performed to stabilize the idle speed. To do. FIG. 5 shows changes in engine torque, air amount, injection timing, and ignition timing when the external load increases, as shown in (A), (B), (C), and (D). When an external load is input, the ECU 9 increases the target torque as shown by the solid line in (A) in order to maintain the idle speed, and sets the target intake air amount in (B) so as to obtain the target torque. The opening degree of the throttle valve 19 is opened by calculation as indicated by the solid line. However, since the intake air flowing into the combustion chamber 21 by the throttle valve 19 is delayed, the response shown by the broken line in FIG. In order to compensate for the response delay of the air amount, the injection timing is retarded as shown in (C), the engine torque is quickly increased to the target torque as shown by the wavy line in (A), and the actual intake air amount becomes the target intake air. Control is performed so that the fuel injection timing is returned to the initial injection timing as the air amount approaches. As shown in (D), when the target torque can be achieved only by changing the fuel injection timing, the ignition timing is not advanced as shown by the solid line a. When the target torque cannot be achieved only by changing the fuel injection timing, the ignition timing is controlled to advance as shown by the broken line b. In this case, as described above, the ignition timing is set as late as possible to achieve the target torque, and control is performed so as to return to the initial ignition timing as the actual intake air amount approaches the target intake air amount. If the target torque can be achieved only by changing the injection timing, the ignition timing is advanced and the reference ignition timing is restored.

  In the present embodiment, by performing the above control, the engine torque indicated by the broken line can be output with respect to the increase in the external load indicated by the solid line in FIG. 5A, minimizing the response delay, and The engine speed during catalyst warm-up idling can be quickly stabilized without minimizing the decrease in exhaust temperature and delaying the warm-up of the three-way catalyst 12.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. Moreover, each component is not limited to the said structure, unless the characteristic function of this invention is impaired.

1 is an overall configuration diagram of an in-cylinder direct injection spark ignition internal combustion engine to which an internal combustion engine and a control device according to the present invention are applied. The flowchart of the idle control in the control apparatus of the cylinder injection type spark ignition internal combustion engine which concerns on invention. The flowchart of the catalyst warm-up idle control in the control apparatus of the cylinder injection type spark ignition internal combustion engine which concerns on this invention. The map of the torque with respect to the injection timing at the time of catalyst warm-up combustion in the control apparatus of the cylinder injection type spark ignition internal combustion engine which concerns on this invention, and ignition timing. The figure which shows the change of the target torque at the time of external load increase, the actual torque, the target intake air amount and the actual intake air amount, the injection timing, and the ignition timing in the control apparatus for the cylinder injection type spark ignition internal combustion engine according to the present invention. The figure which shows the relationship between the exhaust gas temperature with respect to the air fuel ratio at the time of catalyst warm-up combustion in the cylinder direct injection type spark ignition internal combustion engine regarding this invention, and an exhaust gas component. The figure which shows the relationship between the exhaust temperature with respect to the ignition timing at the time of catalyst warm-up combustion, and the indicated mean effective pressure in the direct injection type spark ignition internal combustion engine which concerns on this invention. The figure which shows the exhaust temperature with respect to the injection timing at the time of catalyst warm-up combustion in the cylinder direct injection type spark ignition internal combustion engine which concerns on this invention, and the illustration average effective pressure.

Explanation of symbols

1 Engine 2 Piston 3 Intake Valve 4 Exhaust Valve 5 Fuel Injection Valve 6 Spark Plug 7 Ignition Coil 8 Water Temperature Sensor 9 ECU (Engine Control Unit)
10 Intake pipe 11 Exhaust pipe 12 Three-way catalyst 13 Oxygen sensor 14 EGR valve 15 Collector 16 Crank angle sensor 18 EGR passage 19 Throttle valve 20 AFM
21 Combustion chamber 22 Accelerator opening sensor

Claims (16)

A fuel injection valve that directly injects fuel into the combustion chamber, an exhaust gas purification catalyst in the exhaust gas passage, a rotational speed detection means for the internal combustion engine, a means for determining the warm-up state of the exhaust gas purification catalyst, and an idle state A control device for an in-cylinder injection spark ignition internal combustion engine comprising:
In the control device, the means for determining the idle state determines that the internal combustion engine is in an idle state, and the means for determining the warm-up state of the exhaust gas purification catalyst is that the exhaust gas purification catalyst is not warmed up. In the case of the in-cylinder spark-ignition internal combustion engine, the ignition timing is retarded from the basic advance value and at least the idle speed is controlled by changing the fuel injection timing. Control device.   2. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the control device changes a fuel injection timing within a range of a compression stroke.   The control device retards the fuel injection timing when the actual idle speed detected by the engine speed detection means of the internal combustion engine falls below the target idle speed, and when the actual speed exceeds the target speed 3. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the fuel injection timing is advanced.   4. The control device for a direct injection spark ignition internal combustion engine according to claim 1, wherein the control device changes at least a fuel injection timing and an ignition timing.   The control device advances the ignition timing when the actual idle speed is lower than the target idle speed, and retards the ignition timing when the actual speed exceeds the target speed. Item 5. A control apparatus for a cylinder injection type spark ignition internal combustion engine according to Item 4.   The in-cylinder injection spark according to claim 5, wherein the control device determines and changes a change amount of a fuel injection timing and an ignition timing based on a difference between an actual idle speed and a target idle speed. Control device for an ignition internal combustion engine.   When the difference between the actual idle speed and the target idle speed is small, the control device changes the change amount of the fuel injection timing to be greater than the change amount of the ignition timing, and the difference between the actual idle speed and the target idle speed is changed. 7. The control device for a direct injection spark ignition internal combustion engine according to claim 6, wherein when the value is large, the change amount of the ignition timing is changed by increasing the change amount of the fuel injection timing. A fuel injection valve that directly injects fuel into the combustion chamber; an exhaust gas purification catalyst in the exhaust gas passage; an internal combustion engine speed detection means; an intake air amount measurement means; an idle state determination means; and an exhaust gas purification Means for determining a warm-up state of the catalyst, and calculates a target intake air amount from the difference between the actual idle speed detected by the engine speed detection means and the target idle speed, and adjusts the intake air amount A control device for an in-cylinder injection spark ignition internal combustion engine that changes the intake air amount at
In the control device, the means for determining the idle state determines that the internal combustion engine is in an idle state, and the means for determining the warm-up state of the exhaust gas purification catalyst is that the exhaust gas purification catalyst is not warmed up. If it is determined that the ignition timing is retarded from the basic advance value, the intake air amount is changed by the intake air amount adjusting means, and at least the fuel injection timing is changed from the basic value. A control apparatus for an in-cylinder injection spark ignition internal combustion engine, characterized by controlling an idling speed.   9. The cylinder according to claim 8, wherein the control device returns the fuel injection timing to a basic value as a difference between an actual intake air amount measured by the intake air amount measuring means and a target intake air amount becomes smaller. A control device for an internal injection spark ignition internal combustion engine.   The control device for a direct injection spark ignition internal combustion engine according to claim 8 or 9, wherein the control device changes the fuel injection timing within a range of a compression stroke.   When the actual idle speed falls below the target idle speed, the control device increases the intake air amount by the intake air amount adjusting means and retards the fuel injection timing so that the actual speed exceeds the target speed. 11. The control of a direct injection spark ignition internal combustion engine according to claim 8, wherein the intake air amount adjusting means reduces the intake air amount and advances the fuel injection timing. apparatus.   The in-cylinder injection type according to any one of claims 8 to 11, wherein the control device changes the intake air amount by the intake air amount adjusting means and changes at least the fuel injection timing and the ignition timing. Control device for spark ignition internal combustion engine.   The in-cylinder injection according to claim 12, wherein the control device returns the ignition timing to a value retarded from a basic advance value as the difference between the target intake air amount and the actual intake air amount decreases. -Type spark ignition internal combustion engine control device.   The control device advances the ignition timing when the actual idle speed is lower than the target idle speed, and retards the ignition timing when the actual speed exceeds the target speed. Item 14. The control device for a cylinder injection type spark ignition internal combustion engine according to Item 12 or 13.   The in-cylinder injection spark according to claim 14, wherein the control device determines and changes a change amount of a fuel injection timing and an ignition timing based on a difference between an actual idle speed and a target idle speed. Control device for an ignition internal combustion engine.   When the difference between the actual idle speed and the target idle speed is small, the control device changes the change amount of the fuel injection timing to be greater than the change amount of the ignition timing, and the difference between the actual idle speed and the target idle speed is changed. 16. The control device for a direct injection spark-ignition internal combustion engine according to claim 15, wherein when the value is large, the change amount of the ignition timing is changed by decreasing the change amount of the fuel injection timing.

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