JP2004156626A - Control device of cylinder injection internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase engine control accuracy when fuel evaporated gas is purged into an intake system during the stratified combustion operation of a cylinder injection engine. <P>SOLUTION: During the stratified combustion operation, a fuel injection amount is calculated based on a requested torque, and based on the fuel injection amount, various control parameters are calculated. When the fuel evaporated gas is purged into the intake system during the stratified combustion operation, the fuel injection amount is corrected (correction for reduction of amount) according to the purged amount, and the control parameters (injection timing, ignition timing) that must be set according to the fuel injection amount (actual fuel injection amount) after the purge correction among the various control parameters are corrected according to the purge corrected amount of the fuel injection amount. Thus, the control parameters that must be set according to the actual fuel injection amount (fuel injection amount after the purge correction) and the control parameters that must be set according to the overall fuel amount (fuel injection amount before the purge correction) supplied into a cylinder can be set to appropriate values. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a control device for a direct injection internal combustion engine having a fuel evaporative gas purge system.

  In recent years, the demand for in-cylinder injection engines having the characteristics of low fuel consumption, low exhaust emission, and high output has been rapidly increasing. At low load, this in-cylinder injection engine improves fuel efficiency by injecting a small amount of fuel directly into the cylinder in the compression stroke to form a stratified mixture and stratify combustion, while improving fuel efficiency. In some cases, the engine output is increased by increasing the fuel injection amount and injecting directly into the cylinder during the intake stroke to form a homogeneous mixture and perform homogeneous combustion. During the stratified charge combustion operation, the in-cylinder injection engine calculates a required torque from a driver's accelerator operation amount or the like, calculates a fuel injection amount based on the required torque, and calculates an intake air amount based on the fuel injection amount. (Throttle opening), EGR amount (exhaust gas recirculation amount), valve timing, injection timing, ignition timing, fuel pressure, in-cylinder airflow intensity (swirl flow intensity, tumble flow intensity), and the like are calculated.

Also, in recent gasoline engine vehicles, in order to prevent the fuel evaporative gas from being released from the fuel tank into the atmosphere, the fuel evaporative gas generated in the fuel tank is adsorbed in the canister, and the fuel evaporative gas is absorbed in the canister. The purge control valve is opened and closed to purge (discharge) the fuel evaporative gas in the canister into the intake pipe. In a direct injection type engine equipped with such a fuel evaporative gas purging system, as in the case of the intake pipe injection type engine, during the purging of the fuel evaporative gas, the fuel vapor contained in the purge gas is introduced into the intake pipe. In consideration of this, as disclosed in Patent Document 1, during the purging of fuel evaporative gas, the fuel injection amount is reduced (purge corrected) in accordance with the purge amount, so that the total amount of fuel supplied into the cylinder ( The fuel injection amount + the amount of the purge gas) is prevented from being changed by the purge gas.
JP-A-7-83096

  As shown in FIG. 9, in a conventional in-cylinder injection type engine, during purging of fuel evaporative gas, the fuel injection amount is corrected to be reduced in accordance with the purge amount, and the total fuel amount supplied into the cylinder (fuel injection amount) Therefore, if the required torque is constant, all the engine control parameters other than the fuel injection amount are kept constant. However, during stratified charge combustion operation, in order to form a stratified mixture near the spark plug at an appropriate timing for stratified charge combustion, the injection timing, ignition timing, fuel pressure, etc., among various engine control parameters, are actually determined. It is necessary to set according to the fuel injection amount (fuel injection amount after purge correction). Therefore, as shown in FIG. 9, if all the engine control parameters other than the fuel injection amount are kept constant during the purging of the fuel evaporative gas, the actual fuel injection amount (the fuel injection amount after the purge correction) is reduced. The engine control parameters (injection timing, ignition timing, fuel pressure, etc.) to be set accordingly deviate from appropriate values, so that the combustibility deteriorates, the torque fluctuation increases, and the drivability decreases.

  Further, it is conceivable to set all engine control parameters based on the actual fuel injection amount to be reduced and corrected (the fuel injection amount after the purge correction) during the purge of the fuel evaporative gas. However, during stratified charge combustion operation, in order to reduce the NOx emission while controlling the air-fuel ratio of the entire cylinder in an ultra-lean range, among various engine control parameters, the intake air amount, EGR amount, valve timing, etc. Needs to be set according to the total amount of fuel supplied into the cylinder (fuel injection amount + purge gas amount). Therefore, when all the engine control parameters are set based on the actual fuel injection amount (the fuel injection amount after the purge correction), the setting is made according to the total fuel amount (fuel injection amount + purge gas amount) supplied into the cylinder. Engine control parameters (intake air amount, EGR amount, valve timing, etc.) to be deviated from appropriate values, and the NOx emission amount increases.

  The present invention has been made in view of such circumstances, and accordingly, an object of the present invention is to make it possible to optimize a control parameter when purging fuel evaporative gas into an intake system during a stratified charge combustion operation and to reduce a torque. It is an object of the present invention to provide a control device for a direct injection internal combustion engine that can obtain the effects of suppressing fluctuations and reducing NOx emissions.

  As described above, during the stratified charge combustion operation, in order to form a stratified mixture in the vicinity of the ignition plug at an appropriate timing for stratified charge combustion, among various control parameters, the injection timing, the ignition timing, the fuel pressure, etc. It is necessary to set according to the actual fuel injection amount (fuel injection amount after purge correction). In addition, in order to reduce the NOx emission amount while controlling the air-fuel ratio in the entire cylinder in the super-lean range during the stratified combustion operation, among various control parameters, the intake air amount, the EGR amount, the valve timing, etc. Needs to be set according to the total amount of fuel supplied into the cylinder (fuel injection amount + purging gas amount), that is, the fuel injection amount before purge correction. In short, among the various control parameters, there are a control parameter to be set according to the fuel injection amount after the purge correction and a control parameter to be set according to the total fuel amount supplied into the cylinder.

  Focusing on this point, the control device for a direct injection internal combustion engine according to claim 1 of the present invention, when fuel evaporative gas is purged during stratified charge combustion operation, based on the fuel injection amount before purge correction, A control parameter to be set is calculated according to the total amount of fuel supplied into the cylinder, and other control parameters are calculated based on the fuel injection amount after the purge correction.

  Thereby, the control parameters to be set according to the fuel injection amount before the purge correction and the control parameters to be set according to the fuel injection amount after the purge correction can be set to appropriate values, respectively. The effect of reducing NOx emission can be obtained.

  In this case, the control parameters calculated based on the fuel injection amount before purge correction (total amount of fuel supplied into the cylinder) include the intake air amount, the exhaust gas recirculation amount, and the valve timing. At least one is included, and the control parameter calculated based on the fuel injection amount after purge correction (actual fuel injection amount) includes at least one of the injection timing, the ignition timing, the fuel pressure, and the in-cylinder airflow intensity. It is good to do so. Thus, various control parameters can be calculated with high accuracy even during purging of the fuel evaporative gas.

<< Embodiment (1) >>
Hereinafter, an embodiment (1) of the present invention will be described with reference to FIGS. First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the direct injection engine 11 which is a direct injection internal combustion engine, and the opening thereof is adjusted by a step motor 14 on the downstream side of the air cleaner 13. A throttle valve 15 is provided. When the step motor 14 is driven based on an output signal from an engine electronic control circuit (hereinafter referred to as “ECU”) 16, the opening of the throttle valve 15 (throttle opening) is controlled, and the throttle opening is controlled. The intake air amount to each cylinder is adjusted according to the degree. In the vicinity of the throttle valve 15, a throttle sensor 17 for detecting a throttle opening is provided.

  A surge tank 19 is provided downstream of the throttle valve 15, and an intake manifold 20 for introducing air to each cylinder of the engine 11 is connected to the surge tank 19. A first intake passage 21 and a second intake passage 22 are formed in the intake manifold 20 of each cylinder, and the first intake passage 21 and the second intake passage 22 are formed in each cylinder of the engine 11. The two intake ports 23 are connected to each other.

  An airflow control valve 24 for controlling the swirl flow intensity and the tumble flow intensity in the cylinder is disposed in the second intake passage 22 of each cylinder. The airflow control valve 24 of each cylinder is connected to a step motor 26 via a common shaft 25. When the step motor 26 is driven based on an output signal from the ECU 16, the opening of the airflow control valve 24 is controlled, and the airflow intensity in each cylinder is adjusted according to the opening. An airflow control valve sensor 27 that detects the opening of the airflow control valve 24 is attached to the step motor 26.

  A fuel injection valve 28 for directly injecting fuel into the cylinder is attached to an upper part of each cylinder of the engine 11. The fuel sent from the fuel tank 43 to the fuel delivery pipe 30 through the fuel pipe 29 is directly injected into the cylinder from the fuel injection valve 28 of each cylinder, and is mixed with the intake air introduced from the intake port 23 to form an air-fuel mixture. Is formed.

  Further, an ignition plug (not shown) is attached to a cylinder head of the engine 11 for each cylinder, and the mixture in the cylinder is ignited by spark discharge of each ignition plug. The cylinder discrimination sensor 32 generates an output pulse when a specific cylinder (for example, the first cylinder) reaches the intake top dead center, and the crank angle sensor 33 detects that the crankshaft of the engine 11 has a constant crank angle (for example, 30). A) Generates an output pulse each time it rotates. From these output pulses, the crank angle and the engine rotation speed are detected, and cylinder discrimination is performed.

  On the other hand, the exhaust gas discharged from each exhaust port 35 of the engine 11 joins one exhaust pipe 37 via the exhaust manifold 36. In the exhaust pipe 37, a three-way catalyst 38 for purifying exhaust gas near the stoichiometric air-fuel ratio and a NOx storage type lean NOx catalyst 39 are arranged in series. The lean NOx catalyst 39 adsorbs NOx in the exhaust gas during lean operation in which the oxygen concentration in the exhaust gas is high, and reduces the adsorbed NOx when the air-fuel ratio is switched to rich and the oxygen concentration in the exhaust gas decreases. Purify and release.

  An EGR pipe 40 for recirculating a part of the exhaust gas to the intake system is connected between the upstream side of the three-way catalyst 38 of the exhaust pipe 37 and the surge tank 19, and in the middle of the EGR pipe 40, An EGR valve 41 is provided. The opening of the EGR valve 41 is controlled based on an output signal from the ECU 16, and the EGR amount (exhaust gas recirculation amount) is adjusted according to the opening. Further, the accelerator pedal 18 is provided with an accelerator sensor 42 for detecting an accelerator opening.

  Further, a purge pipe 45 for purging (discharging) the adsorbed fuel evaporative gas into the intake system is connected between the canister 44 for adsorbing the evaporative gas in the fuel tank 43 and the intake pipe 12. A purge control valve 46 is provided on the way. The canister 44, the purge pipe 45, the purge control valve 46 and the like constitute a fuel evaporative gas purge system. The opening degree (duty ratio) of the purge control valve 46 is controlled based on the output signal from the ECU 16, and the purge rate (introduced by the purge control valve 46 with respect to the total amount of air introduced into the cylinder) according to the opening degree. The ratio of the amount of air is adjusted to adjust the purge amount of the fuel evaporative gas.

  Further, a variable valve timing mechanism 47 for varying the valve timing of the intake valve is provided on an intake camshaft (not shown) for driving an intake valve (not shown) of the engine 11. When the variable valve timing mechanism 47 is driven based on the output signal from the ECU 16, the valve timing of the intake valve is adjusted, and the valve overlap amount is adjusted. Note that a variable valve timing mechanism for the exhaust valve may be provided.

  The output signals of the various sensors described above are input to the ECU 16. The ECU 16 mainly includes a microcomputer, and controls the operation of the engine 11 by executing various control programs stored in a built-in ROM (storage medium). The ECU 16 controls the purge amount of the fuel evaporative gas by controlling the purge control valve 46 according to a purge control program of FIG.

  Further, the ECU 16 switches the combustion mode between the stratified combustion mode and the homogeneous combustion mode during the operation of the engine according to the operating state. For example, in the low rotation region and the low torque region, the operation is performed in the stratified combustion mode. During the stratified combustion operation, a small amount of fuel is directly injected into the cylinder in the compression stroke to form a stratified mixture near the spark plug and stratified combustion to improve fuel efficiency. In the middle / high rotation range and the middle / high torque range, the engine is operated in the homogeneous combustion mode. During this homogeneous combustion operation, the engine output is increased by increasing the fuel injection amount and injecting it directly into the cylinder during the intake stroke to form a homogeneous mixture and perform homogeneous combustion.

  As shown in FIG. 2, the ECU 16 calculates the required torque based on the accelerator opening, the engine speed Ne, and the like detected by the accelerator sensor 42 during the stratified charge combustion operation. The required torque is corrected according to a torque correction request (for example, when the tire is idling) from a traction control system or the like, a fuel cut request, or the like. Then, the ECU 16 calculates a fuel injection amount based on the required torque and the like, and based on the fuel injection amount and the engine speed Ne, a target air-fuel ratio, an intake air amount (throttle opening), an EGR amount, a valve timing, By calculating the injection timing, ignition timing, in-cylinder airflow intensity (airflow control valve opening), fuel pressure, and the like, it functions as a control parameter calculation means referred to in the claims, and based on these engine control parameters, The throttle valve 15, the EGR valve 41, the variable valve timing mechanism 47, the fuel injection valve 28, the spark plug, the air flow control valve 24, and the fuel pump are driven.

  Further, the ECU 16 calculates the fuel injection amount based on the required torque and the engine rotation speed Ne by the fuel injection amount calculation program of FIG. 5 described later during the stratified combustion operation, and supplies the fuel injection amount into the cylinder by purging the fuel evaporative gas. In order to prevent a change in the total fuel amount (hereinafter, referred to as “total in-cylinder supply fuel amount”), the fuel injection amount is reduced (purge correction) according to the purge amount of the fuel evaporative gas.

  By the way, in the in-cylinder injection engine 11, when the fuel evaporative gas is not purged, the fuel injection amount injected from the fuel injection valve 28 is equal to the total in-cylinder supply fuel amount. By calculating various engine control parameters based on the injection amount, the engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be set according to the fuel injection amount, and the The engine control parameters (intake air amount, EGR amount, valve timing) to be set accordingly can be set to appropriate values.

  However, during the purging of fuel evaporative gas, the fuel injection amount is reduced by the amount of the purge gas so that the total fuel supply amount in the cylinder becomes equal to the fuel injection amount before the purge correction. The supplied total fuel amount does not match. Therefore, when various engine control parameters are calculated based on the total in-cylinder supply fuel amount (fuel injection amount before purge correction) during purging of fuel evaporative gas, the actual fuel injection amount (fuel injection amount after purge correction) is calculated. ), The engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be set are deviated from appropriate values.

  As a countermeasure, the ECU 16 executes the engine control parameter correction program shown in FIG. 6 so that, when the fuel evaporative gas is purged during the stratified charge combustion operation, the ECU 16 determines the fuel injection amount before the purge correction (total in-cylinder supply fuel amount). Control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be set according to the actual fuel injection amount (fuel injection amount after purge correction) are selected from the various engine control parameters calculated by Then, the fuel injection amount is corrected according to the purge correction amount. Hereinafter, processing contents of each program executed by the ECU 16 will be described.

  [Purge Control] The purge control program shown in FIG. 3 is executed every predetermined time or every predetermined crank angle. When the program is started, first, at step 101, it is determined whether or not a purge execution condition is satisfied. Here, the purge execution conditions include, for example, that the cooling water temperature is higher than a predetermined temperature (for example, 50 ° C.), that there is no request for rich air-fuel ratio, that fuel cut is not being performed, and the like. If all of these conditions are satisfied, the purge execution condition is satisfied. However, if any one of the conditions is not satisfied, the purge execution condition is not satisfied.

  If the purge execution condition is satisfied, the routine proceeds to step 102, where the evaporative concentration learning value KPG is read. The evaporation concentration learning value KPG indicates the concentration of the fuel evaporative gas purged from the canister 44, and is updated every predetermined time or every predetermined crank angle by an evaporation concentration learning program (not shown).

  Thereafter, the routine proceeds to step 103, where the fuel injection amount correction limit value KTPG is calculated from the map shown in FIG. 4 according to the required torque and the engine rotation speed Ne. The fuel injection amount correction limit value KTPG is a correction limit value when the fuel injection amount is purge corrected (reduced amount correction) according to the purge amount of the fuel evaporative gas. The map of the fuel injection amount correction limit value KTPG in FIG. 4 is set such that the fuel injection amount correction limit value KTPG becomes smaller as the engine rotation speed Ne and the required torque become smaller (the fuel injection amount becomes smaller).

  Thereafter, the routine proceeds to step 104, where the purge rate PG is obtained by dividing the fuel injection amount correction limit value KTPG by the evaporation concentration learning value KPG.

PG = KTPG / KPG
The ECU 16 controls the purge amount of the fuel evaporative gas by opening and closing the purge control valve 46 so as to maintain the purge rate PG during the purging of the fuel evaporative gas.

  On the other hand, if it is determined in step 101 that the purge execution condition is not satisfied, the process proceeds to step 105, in which the purge rate PG is set to 0, the purging of the fuel evaporative gas is prohibited, and the fuel injection amount correction limit value is set. KTPG is set to 0, and the program ends.

  [Calculation of Fuel Injection Amount] The fuel injection amount calculation program of FIG. 5 is executed at predetermined time intervals or at predetermined crank angle intervals in the stratified combustion mode operation. When this program is started, first, in step 201, the required torque and the engine rotational speed Ne are read, and in the next step 202, a map of the basic fuel injection amount QBASE using the engine rotational speed Ne and the required torque as parameters is searched. To calculate the basic fuel injection amount QBASE. Note that the basic fuel injection amount QBASE may be corrected by multiplying it by various correction coefficients (water temperature correction coefficient, feedback correction coefficient, learning correction coefficient, etc.).

  Thereafter, the process proceeds to step 203, where the fuel injection amount correction limit value KTPG calculated in step 103 of FIG. 3 is read, and in the next step 204, the total fuel supply in the cylinder is prevented from being changed by purging of the fuel evaporative gas. For this purpose, the basic fuel injection amount QBASE is corrected by the following equation using the fuel injection amount correction limit value KTPG, thereby performing a purge correction according to the purge amount and calculating the final fuel injection amount QINJ.

QINJ = QBASE-QBASE × KTPG
When the purge of the fuel evaporative gas is not executed, since the fuel injection amount correction limit value KTPG is set to 0, the purge correction is not performed and QINJ = QBASE. The processing of step 204 plays a role corresponding to the fuel injection amount correcting means described in the claims.

  [Engine Control Parameter Correction] The engine control parameter calculation program shown in FIG. 6 is executed every predetermined time or every predetermined crank angle, and plays a role as a control parameter correction means referred to in the claims. When the program is started, first, in step 301, it is determined whether or not the current combustion mode is the stratified combustion mode. If the current combustion mode is the homogeneous combustion mode, the program is terminated.

  On the other hand, when the stratified combustion mode is determined, the process proceeds to step 302, where it is determined whether the purging of the fuel evaporative gas is being performed. If the purging is not being performed, the purge correction of the fuel injection amount has not been performed. It is determined that the injection timing, the ignition timing, the in-cylinder airflow intensity, and the fuel pressure are appropriate values, and the program is terminated as it is.

  On the other hand, when it is determined that the current combustion mode is the stratified combustion mode and the fuel evaporative gas purge is being executed, the fuel injection amount is purge-corrected, so that the fuel injection amount is set according to the actual fuel injection amount. It is determined that the engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be deviated from appropriate values, and the routine proceeds to step 303, where the fuel injection amount before purge correction (total in-cylinder supply fuel amount) is reduced. Engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be set in accordance with the actual fuel injection amount (fuel injection amount after purge correction) from various engine control parameters calculated based on this Is corrected. At this time, the correction amount of each engine control parameter is calculated based on a correction amount map (see FIG. 2) set according to the purge correction amount of the fuel injection amount.

  It should be noted that from among the four engine control parameters of the injection timing, the ignition timing, the in-cylinder airflow intensity, and the fuel pressure, one to three engine control parameters having a large influence on the combustion stabilization may be selected and corrected. Further, these engine control parameters may be corrected according to the purge amount.

  A control example when each of the programs described above is executed will be described with reference to a time chart of FIG. When the purge execution condition is satisfied during the stratified charge combustion operation and the purge of the fuel evaporative gas is performed, the fuel injection amount is purge-corrected according to the purge amount. Further, during the purging of the fuel evaporative gas, the actual fuel injection amount (the fuel after the purge correction) is selected from various engine control parameters calculated based on the fuel injection amount before the purge correction (total in-cylinder fuel amount). The engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) to be set according to the injection amount are corrected in accordance with the purge correction amount of the fuel injection amount (FIG. 7 shows the in-cylinder airflow). The illustration of strength and fuel pressure is omitted).

  As a result, even when the fuel evaporative gas is purged during the stratified charge combustion operation, the engine control parameters (injection timing, ignition timing, in-cylinder air flow intensity) to be set according to the actual fuel injection amount (fuel injection amount after purge correction) , Fuel pressure) can be set to an appropriate value, the combustion state can be stabilized, the torque fluctuation can be suppressed small, and the drivability can be improved. In addition, among various engine control parameters calculated based on the fuel injection amount before purge correction (total in-cylinder supply fuel amount), it should be set according to the actual fuel injection amount (fuel injection amount after purge correction). Since only the engine control parameters are corrected, the engine control parameters (intake air amount, EGR amount, valve timing) to be set according to the total in-cylinder supply fuel amount (fuel injection amount before purge correction) are maintained at appropriate values. And the NOx reduction effect can be kept good.

<< Embodiment (2) >>
Next, an embodiment (2) of the present invention will be described with reference to FIG. The difference between the embodiment (1) and the embodiment (2) is only a method of determining an engine control parameter to be set according to the fuel injection amount after purge correction (actual fuel injection amount). That is, in the embodiment (1), after all the engine control parameters are calculated based on the fuel injection amount before the purge correction, the fuel injection amount after the purge correction (actual fuel injection amount) is selected from the engine control parameters. In contrast, in the second embodiment, the fuel injection amount before the purge correction (total in-cylinder supply fuel amount) is selected. Control parameters (target air-fuel ratio, intake air amount, EGR amount, valve timing) to be set according to the engine control parameters to be set according to the fuel injection amount after purge correction (actual fuel injection amount) Injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure). Then, only the former engine control parameters (the target air-fuel ratio, the intake air amount, the EGR amount, and the valve timing) are changed to the fuel injection amount before purge correction (total in-cylinder supply fuel amount) as in the first embodiment. Calculated based on On the other hand, the latter engine control parameters (injection timing, ignition timing, in-cylinder airflow intensity, fuel pressure) are calculated based on the fuel injection amount after purge correction (actual fuel injection amount). In this case, the latter correction of the engine control parameters is unnecessary.

  Also in this embodiment (2), similarly to the embodiment (1), the engine control parameters to be set according to the fuel injection amount before purge correction (total in-cylinder supply fuel amount) and the fuel injection after purge correction Engine control parameters to be set according to the amount (actual fuel injection amount) can be set to appropriate values, respectively, and the effects of suppressing torque fluctuation and reducing NOx emission can be obtained.

  Also in this embodiment (2), purging is performed by selecting one to three parameters having a large influence on combustion stabilization among the four engine control parameters of injection timing, ignition timing, in-cylinder airflow intensity, and fuel pressure. The calculation may be performed based on the corrected fuel injection amount, and the remaining engine control parameters may be calculated based on the fuel injection amount before the purge correction.

1 is a schematic configuration diagram of an entire engine control system showing an embodiment (1) of the present invention. Functional block diagram for explaining a method of determining an engine control parameter during fuel evaporative gas purge during stratified charge combustion operation according to the embodiment (1). Flow chart showing the processing flow of the purge control program FIG. 5 is a diagram conceptually showing an example of a map of a fuel injection amount correction limit value KTPG. Flow chart showing the flow of processing of the fuel injection amount calculation program Flow chart showing the flow of processing of the engine control parameter correction program Time chart showing a control example of the embodiment (1) Functional block diagram for explaining a method of determining an engine control parameter during fuel evaporative gas purge during stratified charge combustion operation according to the embodiment (2). Time chart showing a conventional control example

Explanation of reference numerals

  11: In-cylinder injection type engine (in-cylinder injection type internal combustion engine), 12: intake pipe, 15: throttle valve, 16: ECU (control parameter calculation means, fuel injection amount correction means, control parameter correction means), 24: air flow Control valve, 28: fuel injection valve, 41: EGR valve, 42: accelerator sensor, 43: fuel tank, 44: canister, 46: purge control valve, 47: variable valve timing mechanism.

Claims (2)

In a direct injection internal combustion engine having a fuel evaporative gas purge system for adsorbing fuel evaporative gas generated in a fuel tank into a canister and purging fuel evaporative gas in the canister to an intake system according to an operation state,
Control parameter calculation means for calculating a fuel injection amount based on the required torque during the stratified charge combustion operation for injecting fuel in the compression stroke, and calculating various control parameters based on the fuel injection amount;
Fuel injection amount correction means for reducing the fuel injection amount in accordance with the purge amount of the fuel evaporative gas (hereinafter referred to as “purge correction”),
The control parameter calculating means, when the fuel evaporative gas is purged during the stratified charge combustion operation, based on the fuel injection amount before the purge correction, a control parameter to be set according to the total amount of fuel supplied into the cylinder. And calculating another control parameter based on the fuel injection amount after the purge correction. The control parameter calculated based on the fuel injection amount before the purge correction includes at least one of an intake air amount, an exhaust gas recirculation amount, and a valve timing, and the control calculated based on the fuel injection amount after the purge correction. The control device for a direct injection internal combustion engine according to claim 1, wherein the parameter includes at least one of an injection timing, an ignition timing, a fuel pressure, and an in-cylinder airflow intensity.