JP3536596B2 - Fuel injection control device for direct injection spark ignition type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection control device for a direct injection spark ignition type internal combustion engine.

[0002]

2. Description of the Related Art In recent years, a direct-injection spark ignition type internal combustion engine has attracted attention. In this engine, a combustion system is switched according to operating conditions of the engine, that is, by injecting fuel in an intake stroke. And homogeneous combustion in which fuel is diffused into the combustion chamber to form a homogeneous mixture, and stratified combustion in which fuel is injected in the compression stroke to form a layered mixture intensively around the spark plug. (See Japanese Patent Application Laid-Open No. 59-37236).

[0003]

In a fuel injection control device for an internal combustion engine, a cylinder intake air amount is calculated every predetermined time, and a fuel injection amount is calculated based on the cylinder intake air amount so as to obtain a target air-fuel ratio. Then, at the injection timing, the latest calculated value of the fuel injection amount is read and set for injection.

However, in a direct injection spark ignition type internal combustion engine, when fuel is injected after the intake valve is closed, such as during stratified charge combustion, the fuel is injected based on the cylinder intake air amount calculated near the injection timing. When the amount is calculated and set, the actual cylinder intake air amount is determined at the intake valve closing timing, so the fuel injection amount does not match the actual cylinder intake air amount, and the air-fuel ratio cannot be controlled correctly to the target air-fuel ratio. There was a problem.

In the case of performing fuel injection before the intake valve close timing, such as during homogeneous combustion, if the fuel injection amount is calculated and set based on the cylinder intake air amount calculated near the injection timing, the actual fuel injection amount is calculated. Since the cylinder intake air amount is determined when the intake valve is closed, the fuel injection amount is insufficient to match the actual cylinder intake air amount, especially during acceleration, and the air-fuel ratio cannot be controlled to the target air-fuel ratio correctly. was there.

As a result of the inability to properly control the air-fuel ratio to the target air-fuel ratio, for example, during stratified charge combustion, the air-fuel ratio around the spark plug cannot be suppressed to an appropriate range. It was found that the results were unfavorable in terms of performance and exhaust performance (torque was not as intended, and three exhaust components increased). It is also known that even during homogeneous combustion, turbulence in the air-fuel ratio has a large effect on drivability and exhaust performance.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention performs air-fuel ratio control in a direct injection spark ignition type internal combustion engine by performing fuel injection amount control based on the cylinder intake air amount at the intake valve closing timing. The purpose is to greatly improve the accuracy of the.

[0008]

According to the first aspect of the present invention, there is provided a direct injection spark ignition system including a fuel injection valve for directly injecting fuel into a combustion chamber and injecting fuel after an intake valve closing timing. in an internal combustion engine, as shown in FIG. 1 (a), the intake valve and the intake valve closing timing detecting means for detecting the closing timing, the intake valve closing timing cylinder intake air amount to calculate the cylinder intake air quantity at the intake valve closing timing a calculation means, calculated at the intake valve closing timing
A fuel injection amount setting means for setting a current fuel injection amount at an injection timing after an intake valve closing timing based on the selected cylinder intake air amount, and a fuel injection control device for a direct injection spark ignition type internal combustion engine. Is composed.

According to the second aspect of the present invention, the intake valve closing timing cylinder intake air amount calculating means calculates the cylinder intake air amount at predetermined time intervals as shown in FIG. 2B. It is characterized by including an amount calculating means and a holding means for holding the cylinder intake air amount calculated near the intake valve closing timing. According to the third aspect of the present invention, as shown in FIG. 1C, in a direct injection spark ignition type internal combustion engine having a fuel injection valve for directly injecting fuel into the combustion chamber and injecting fuel after the intake valve closing timing. To
A time-synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount every predetermined time; a time-synchronous fuel injection amount calculating means for calculating a fuel injection amount based on the cylinder intake air amount every predetermined time; Intake valve closing timing detecting means for detecting the timing, holding means for holding the fuel injection amount calculated near the intake valve closing timing, and injection timing after the intake valve closing timing based on the held fuel injection amount. and the fuel injection amount setting means for setting a fuel <br/> fuel injection amount of time in the provided,
A fuel injection control device for a direct injection spark ignition type internal combustion engine is provided.

According to a fourth aspect of the invention, there is provided a fuel injection valve for directly injecting fuel into the combustion chamber, wherein a normal injection is performed before the intake valve close timing, and an additional injection is performed after the intake valve close timing. In the flower ignition type internal combustion engine, as shown in FIG. 2A, a time-synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount at predetermined time intervals, and near a normal injection timing before the intake valve closing timing. A normal injection fuel injection amount setting means for setting a normal injection fuel injection amount at a normal injection timing before the intake valve closing timing based on the calculated cylinder intake air amount, and an intake valve detecting the intake valve closing timing Closing timing detecting means, based on a value obtained by subtracting a cylinder intake air amount based on a fuel injection amount setting for normal injection before the intake valve closing timing from a cylinder intake air amount calculated near the intake valve closing timing. , When the intake valve is closed And additional injection fuel injection amount setting means for setting a fuel injection amount of the current <br/> for additional injection of additional injection timing of the later, the provided, a fuel injection control apparatus for a direct eruption flowers ignition type internal combustion engine I do.

According to a fifth aspect of the present invention, there is provided a fuel injection valve for directly injecting fuel into the combustion chamber, wherein a normal injection is performed before the intake valve close timing, and an additional injection is performed in which additional injection is performed after the intake valve close timing. In the flower ignition type internal combustion engine, as shown in FIG. 2 (B), a time-synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount every predetermined time, and a fuel based on the cylinder intake air amount every predetermined time. A time-synchronous fuel injection amount calculating means for calculating an injection amount, and a fuel injection amount calculated in the vicinity of the normal injection timing before the intake valve closing timing, for normal injection at a normal injection timing before the intake valve closing timing. A normal injection fuel injection amount setting means for setting a fuel injection amount, an intake valve closing timing detecting means for detecting an intake valve closing timing, and a fuel injection amount calculated before and after the intake valve closing timing calculated in the vicinity of the intake valve closing timing. For regular injection Was based on a value obtained by subtracting the fuel injection amount, and the current additional injection fuel injection amount setting means for setting a fuel injection amount for the add <br/> pressurized injection in additional injection timing of the intake valve closing timing or later, the And a fuel injection control device for a direct injection spark ignition type internal combustion engine.

In the invention according to a sixth aspect, the time-synchronous intake air amount calculating means performs a delay process on the intake air amount detected based on a signal from an air flow meter disposed in the intake passage to perform the cylinder intake air amount calculation. Is calculated.

[0013]

According to the first aspect of the invention, when fuel injection is performed after the intake valve close timing, the cylinder intake air amount at the intake valve close timing is calculated, and based on this, the cylinder intake air amount is calculated based on this. Since the fuel injection amount at the injection timing of is set, it becomes possible to correctly control the air-fuel ratio to the target air-fuel ratio,
Drivability and exhaust performance during stratified combustion can be improved.

According to the second aspect of the present invention, when the cylinder intake air amount is calculated every predetermined time, the cylinder intake air amount calculated near the intake valve closing timing is held, whereby the intake air is maintained. The cylinder intake air amount at the time of valve closing can be accurately obtained. According to the third aspect of the present invention, when the cylinder intake air amount is calculated every predetermined time and the fuel injection amount is calculated based on this at the same time, the fuel injection calculated near the intake valve closing timing By maintaining the fuel injection amount and setting the fuel injection amount at the injection timing after the intake valve closing timing based on this, it is possible to correctly control the air-fuel ratio to the target air-fuel ratio, and to improve the operability during stratified combustion etc. And exhaust performance can be improved.

According to the present invention, when the cylinder intake air amount is calculated every predetermined time, the cylinder intake air amount is calculated based on the cylinder intake air amount calculated near the normal injection timing before the intake valve closing timing. On the other hand, while setting the fuel injection amount for normal injection, based on the value obtained by subtracting the cylinder intake air amount during normal injection from the cylinder intake air amount calculated near the intake valve close timing, Since the fuel injection amount for additional injection at the additional injection timing is set, it is possible to correctly control the air-fuel ratio to the target air-fuel ratio even during acceleration, and to improve drivability and exhaust performance during homogeneous combustion. Can be improved.

According to the fifth aspect of the present invention, when the cylinder intake air amount is calculated every predetermined time and the fuel injection amount is calculated based on this at the same time, the normal injection timing before the intake valve closing timing is obtained. Based on the fuel injection amount calculated in the vicinity,
While setting the fuel injection amount for normal injection, the additional injection timing after the intake valve closing timing is based on the value obtained by subtracting the fuel injection amount during normal injection from the fuel injection amount calculated near the intake valve closing timing. Since the fuel injection amount for additional injection is set, it is possible to correctly control the air-fuel ratio to the target air-fuel ratio even during acceleration, and to improve operability and exhaust performance during homogeneous combustion. it can.

According to the sixth aspect of the present invention, when calculating the cylinder intake air amount, the intake air amount detected based on a signal from an air flow meter disposed in the intake passage is subjected to a delay process to perform the cylinder intake air amount. By calculating the air amount, the cylinder intake air amount can be accurately obtained.

[0018]

Embodiments of the present invention will be described below. FIG. 3 is a system diagram of a direct injection spark ignition type internal combustion engine showing one embodiment. First, this will be described.
Air is sucked into the combustion chamber of each cylinder of the internal combustion engine 1 mounted on the vehicle from the air cleaner 2 by the intake passage 3 under the control of the electronically controlled throttle valve 4.

The opening of the electronically controlled throttle valve 4 is controlled by a step motor or the like operated by a signal from the control unit 20. An electromagnetic fuel injection valve (injector) 5 is provided so as to directly inject fuel (gasoline) into the combustion chamber. The fuel injection valve 5 is energized by a solenoid in response to an injection pulse signal output in the intake stroke or the compression stroke from the control unit 20 in synchronization with the engine rotation, opens the valve, and injects fuel adjusted to a predetermined pressure. It has become. The injected fuel diffuses into the combustion chamber in the case of the intake stroke injection to form a homogeneous mixture, and in the case of the compression stroke injection, forms a layered mixture intensively around the ignition plug 6. Based on the ignition signal from the control unit 20, the fuel is ignited by the ignition plug 6 and burns (homogeneous combustion or stratified combustion). The combustion method is a combination of air-fuel ratio control and homogeneous stoichiometric combustion.
It is divided into homogeneous lean combustion and stratified lean combustion.

The exhaust gas from the engine 1 is exhausted from an exhaust passage 7, and an exhaust purification catalyst 8 is interposed in the exhaust passage 7. The control unit 20 includes a CPU, a ROM, an R
A microcomputer including an AM, an A / D converter, an input / output interface, and the like is provided, and signals are input from various sensors.

The various sensors include a crank angle sensor 2 for detecting rotation of a crankshaft or a camshaft of the engine 1.
1 and 22 are provided. These crank angle sensors 21 and 22 have a crank angle of 720 when the number of cylinders is n.
The reference pulse signal RE is set at a predetermined crank angle position (a predetermined crank angle position before the compression top dead center of each cylinder) at every ° / n.
F and outputs a unit pulse signal PO every 1 to 2 °.
S is output, and the engine speed Ne can be calculated from the period of the reference pulse signal REF and the like.

In addition, an air flow meter 23 for detecting the intake air flow rate Qa upstream of the throttle valve 4 in the intake passage 3,
Accelerator sensor 24 for detecting accelerator opening (accelerator pedal depression amount) ACC, opening TV of throttle valve 4
A throttle sensor 25 for detecting O (including an idle switch that is turned on when the throttle valve 4 is fully closed), a water temperature sensor 26 for detecting a cooling water temperature Tw of the engine 1, and a rich / lean exhaust air-fuel ratio in the exhaust passage 7. etc. are provided O ₂ sensor 27, a vehicle speed sensor 28 for detecting the vehicle speed VSP for outputting a signal corresponding to the.

Here, the control unit 20
Performs predetermined arithmetic processing by a built-in microcomputer while inputting signals from the various sensors, and performs a throttle opening degree by the electronically controlled throttle valve 4, a fuel injection amount and an injection timing by the fuel injection valve 5, The ignition timing of the ignition plug 6 is controlled. Regarding the throttle control (control of the electronically controlled throttle valve 4), the motor of the electronically controlled throttle valve 4 is opened by driving the motor of the electronically controlled throttle valve 4 in accordance with the engine target torque tTRQ set from the accelerator opening ACC and the engine speed Ne. Control the degree.

For the fuel injection control (control of the fuel injection valve 5), a combustion method is set according to the engine operating conditions, and the fuel injection amount and the injection timing by the fuel injection valve 5 are controlled accordingly. More specifically, a map in which the combustion method is determined using the engine speed Ne and the basic fuel injection amount Tp as parameters,
A plurality of water temperature Tw, time after starting, etc. are provided for each condition,
From the map selected from these conditions, the combustion method is set to one of homogeneous stoichiometric combustion, homogeneous lean combustion, or stratified lean combustion in accordance with the parameters of the actual operating state of the engine.

In the case of homogeneous stoichiometric combustion as a result of the determination of the combustion system, the fuel injection amount is set to a value corresponding to the stoichiometric air-fuel ratio (14.6), and the air-fuel ratio feedback control by the O ₂ sensor 27 is performed. To the intake stroke,
Perform homogeneous stoichiometric combustion. In the case of the homogeneous lean combustion, the fuel injection amount is set to a value corresponding to the lean air-fuel ratio of the air-fuel ratio of 20 to 30, and the open control is performed, while the injection timing is set to the intake stroke to perform the homogeneous lean combustion. In the case of stratified lean combustion, the fuel injection amount is set to a value corresponding to a lean air-fuel ratio of about 40, and the open control is performed, while the injection timing is set to the compression stroke to perform the stratified lean combustion. .

Regarding the ignition control (control of the ignition plug 6),
The ignition timing ADV is set and controlled by referring to a map using the engine speed Ne and the basic fuel injection amount Tp as parameters for each combustion method. Next, as a first embodiment of the fuel injection control according to the present invention, the fuel injection control in the case where the fuel injection is performed after the intake valve closing timing (during the compression stroke) during the stratified combustion will be described with reference to FIGS. This will be described with reference to the flowchart of FIG.

FIG. 4 shows a fuel injection amount calculation routine, which is executed at predetermined time intervals, specifically, as a 10 ms job. In S1, the intake air flow rate Qa detected by the air flow meter 23 is read. In S2, a raw basic fuel injection amount (pulse width) RTp corresponding to the intake air amount per combustion is calculated by the following equation using the intake air flow rate Qa and the engine speed Ne.

RTp = K × Qa / Ne where K is a constant. In S3, the raw basic fuel injection amount RTp is subjected to a manifold filling delay by the following equation (weighted average equation) to calculate a basic fuel injection amount (pulse width) Tp corresponding to the cylinder intake air amount. . Tp = RTp × Fload + Tp ₋₁ × (1−Fload) where Fload is a weighted average ratio constant, and Tp ₋₁ is the previous value of Tp.

In S4, various corrections are made to the basic fuel injection amount Tp corresponding to the cylinder intake air amount by the following equation,
The final fuel injection amount (pulse width) Ti is calculated. Ti = Tp × KTR × TFBYA × α × αm + Ts where KTR is a transient correction coefficient, TFBYA is a target equivalence ratio (= 14.6 / target air-fuel ratio) corresponding to a combustion method or the like, α is an air-fuel ratio feedback correction coefficient, αm Is the learning correction coefficient,
Ts is an invalid injection amount (invalid pulse width).

FIG. 5 shows a job executed at the intake valve closing timing (IVC; a predetermined crank angle position detected by the crank angle sensors 21 and 22). In this job, FIG.
Latest fuel injection amount T calculated by the 10 ms job
i is read and stored as the fuel injection amount TiC = Ti at the intake valve closing timing. FIG. 6 shows the injection timing (I
This is a job executed in T).

In this job, when performing the injection in the compression stroke, the fuel injection amount TiC at the intake valve closing timing stored and held in the IVC job in FIG. 5 is set in the output register for the injection time control. As a result, an injection pulse signal having a pulse width of TiC is output to the fuel injection valve 5, and fuel injection is performed. The operation of the first embodiment will be described with reference to FIG.

A cylinder intake air amount is calculated every 10 ms, and a fuel injection amount Ti is calculated based on the calculated amount.
Then, when the intake valve is closed, the latest fuel injection amount Ti is set to T
Store as iC. Then, at the injection timing after the intake valve closing timing, the fuel injection amount TiC at the intake valve closing timing stored and held is set as the actually injected fuel injection amount.

If the latest Ti calculated near the injection timing is used, as in the conventional case, the cylinder intake air amount is specified at the intake valve closing timing, but the acceleration is performed after the intake valve closing timing. T based on the cylinder intake air amount increased
i, the fuel injection amount becomes excessive compared to the actual cylinder intake air amount, and the air-fuel ratio cannot be suppressed to the vicinity of the target air-fuel ratio. In this regard, according to the present invention, since the fuel injection amount TiC corresponds to the cylinder intake air amount at the time of closing the intake valve, the air-fuel ratio can be accurately controlled to the target air-fuel ratio.

The means for detecting the closing timing of the intake valve according to claim 1 is
The intake valve closing timing cylinder intake air amount calculating means corresponds to the crank angle sensor for starting the IVC job in FIG. 5, and the fuel injection amount T corresponding to the cylinder intake air amount at the intake valve closing timing.
4 and 5 for determining iC, and the fuel injection amount setting means corresponds to the job in FIG. Further, in the intake valve closing timing cylinder intake air amount calculating means of claim 1,
The time-synchronous cylinder intake air amount calculating means in claim 2 corresponds to the job in FIG. 4 for calculating the fuel injection amount Ti corresponding to the cylinder intake air amount, and the holding means calculates the cylinder intake air amount at the intake valve closing timing. This corresponds to the job of FIG. 5 that holds the corresponding fuel injection amount TiC.

The time-synchronous cylinder intake air amount calculating means corresponds to S1 to S3 in FIG. 4 for calculating the basic fuel injection amount Tp corresponding to the cylinder intake air amount. 4, the intake valve closing timing detecting means corresponds to the crank angle sensor for starting the IVC job in FIG. 5, the holding means corresponds to the job in FIG. 5, and the fuel injection amount setting means corresponds to S4 in FIG. , Corresponds to the job in FIG.

Next, as a second embodiment of the fuel injection control according to the present invention, during homogeneous combustion, regular injection is performed before the intake valve close timing (during the intake stroke), and after the intake valve close timing (the intake valve close timing). The fuel injection control when the additional injection is performed during the timing or during the compression stroke will be described with reference to the flowcharts of FIGS. The 10 ms job in FIG. 4 is executed in the same manner as in the first embodiment, whereby the fuel injection amount Ti corresponding to the cylinder intake air amount is calculated every 10 ms.

FIG. 7 shows a job executed at the injection timing (IT) of the intake stroke. In S11, the latest fuel injection amount Ti calculated by the 10 ms job in FIG.
When the fuel is injected in the intake stroke, the fuel injection amount Ti is set in an output register for controlling the injection time. This allows
An injection pulse signal having a pulse width of Ti is output to the fuel injection valve 5, and normal fuel injection is performed.

In step S12, the fuel injection amount Ti at this time is stored and held as the normal injection fuel injection amount TiIn = Ti. FIG. 8 shows a job executed at the intake valve closing timing (IVC; a predetermined crank angle position detected by the crank angle sensors 21 and 22). In S21, it is determined whether or not the acceleration is performed (for example, the idle switch is changed from ON to OFF).

At S22, the latest fuel injection amount Ti calculated by the 10 ms job in FIG. 4 is read as the fuel injection amount at the intake valve closing timing, and the fuel injection amount Ti is calculated from the fuel injection amount Ti as shown in the following equation. The fuel injection amount TiIn during normal injection stored and retained by the job is subtracted, and the invalid injection amount T
By adding s, the fuel injection amount TiW for additional injection is calculated.

TiW = Ti−TiIn + Ts In S23, the fuel injection amount T is used for additional injection.
iW is set in the output register for controlling the injection time. As a result, an injection pulse signal having a pulse width of TiW is output to the fuel injection valve 5, and additional fuel injection is performed. The operation of the second embodiment will be described with reference to FIG.

The cylinder intake air amount is calculated every 10 ms, and the fuel injection amount Ti is calculated based on this. Then, at the regular injection timing before the intake valve closing timing, the regular injection is performed with the latest fuel injection amount Ti. The fuel injection amount Ti at this time is stored and held as TiIn. At the time of acceleration, additional injection is performed at the intake valve closing timing by subtracting the fuel injection amount TiIn in the regular injection from the latest fuel injection amount Ti at that time.

Thus, even during acceleration, a total fuel injection amount corresponding to the cylinder intake air amount at the intake valve closing timing can be obtained by additional injection, and the air-fuel ratio can be accurately controlled to the target air-fuel ratio. it can. The time-synchronous cylinder intake air amount calculating means of claim 4 corresponds to the job of FIG. 4 for calculating the fuel injection amount Ti corresponding to the cylinder intake air amount, and the normal injection fuel injection amount setting means corresponds to FIG. The intake valve closing timing detecting means corresponds to the crank angle sensor for starting the IVC job in FIG. 8, and the additional injection fuel injection amount setting means corresponds to the job in FIG. 8 (and S12 in FIG. 7). Is equivalent to

The time-synchronous cylinder intake air amount calculating means corresponds to S1 to S3 in FIG. 4 for calculating the basic fuel injection amount Tp corresponding to the cylinder intake air amount. 4 corresponds to S4 in FIG. 4, the normal injection fuel injection amount setting means corresponds to S11 in FIG. 7, and the intake valve closing timing detecting means corresponds to a crank angle sensor for starting the IVC job in FIG. The fuel injection amount setting means for additional injection corresponds to the job in FIG. 8 (and S12 in FIG. 7).

In the second embodiment, the additional injection is performed at I
The VC job was performed at the intake valve closing timing. However, the 10 ms job may be used to determine whether or not the intake valve has just been closed, and the additional injection may be performed immediately after the intake valve closing timing.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a functional block diagram showing a configuration of the present invention.

FIG. 3 is a system diagram of an internal combustion engine showing an embodiment of the present invention.

FIG. 4 is a flowchart of a 10 ms job according to the first and second embodiments.

FIG. 5 is a flowchart of an intake valve closing timing job according to the first embodiment;

FIG. 6 is a flowchart of a compression stroke injection job according to the first embodiment.

FIG. 7 is a flowchart of an intake stroke injection job according to a second embodiment.

FIG. 8 is a flowchart of an intake valve closing timing job according to the second embodiment.

FIG. 9 is a time chart of the first and second embodiments.

[Explanation of symbols]

1 Internal combustion engine 4 Electric throttle valve 5 Fuel injection valve 6 Spark plug 20 Control unit 21, 22 Crank angle sensor 23 Air flow meter 24 Accelerator sensor

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-71383 (JP, A) JP-A-8-284737 (JP, A) JP-A-2-264141 (JP, A) JP-A-6-264141 101554 (JP, A) JP-A-3-23341 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00-41/40, 45/00

Claims (6)

(57) [Claims] 1. A direct injection spark ignition type internal combustion engine having a fuel injection valve for directly injecting fuel into a combustion chamber and injecting fuel after the intake valve close timing, wherein the intake valve closing timing for detecting the intake valve close timing. and detecting means, and the intake valve closing timing cylinder intake air quantity calculating means for calculating a cylinder intake air quantity at the intake valve closing timing, based on the cylinder intake air amount calculated by the intake valve closing timing, the intake valve closing timing A fuel injection control device for a direct injection spark ignition type internal combustion engine, comprising: fuel injection amount setting means for setting a current fuel injection amount at a subsequent injection timing. 2. The intake valve closing timing cylinder intake air amount calculating means includes a time synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount at predetermined time intervals, and a cylinder calculated near the intake valve closing timing. 2. A fuel injection control device for a direct injection spark ignition type internal combustion engine according to claim 1, further comprising a holding unit for holding an intake air amount. 3. A direct injection spark ignition type internal combustion engine having a fuel injection valve for directly injecting fuel into a combustion chamber and injecting fuel after an intake valve close timing calculates a cylinder intake air amount at predetermined time intervals. Time synchronous cylinder intake air amount calculating means, time synchronous fuel injection amount calculating means for calculating a fuel injection amount based on the cylinder intake air amount at predetermined time intervals, and intake valve closing timing detecting means for detecting intake valve closing timing. Holding means for holding the fuel injection amount calculated near the intake valve closing timing; and fuel injection for setting the current fuel injection amount at the injection timing after the intake valve closing timing based on the held fuel injection amount. A fuel injection control device for a direct injection spark ignition type internal combustion engine, comprising: an amount setting unit. 4. A direct-injection spark ignition type internal combustion engine having a fuel injection valve for directly injecting fuel into a combustion chamber, performing normal injection before an intake valve close timing and performing additional injection after an intake valve close timing. A time-synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount at predetermined time intervals; and a cylinder intake air amount before the intake valve closing timing based on a cylinder intake air amount calculated near the normal injection timing before the intake valve closing timing. A normal injection fuel injection amount setting means for setting a normal injection fuel injection amount at a normal injection timing, an intake valve closing timing detecting means for detecting an intake valve closing timing, and a value calculated in the vicinity of the intake valve closing timing. Based on the value obtained by subtracting the cylinder intake air amount based on the fuel injection amount setting for normal injection before the intake valve closing timing from the cylinder intake air amount, the current additional injection at the additional injection timing after the intake valve closing timing of A fuel injection control device for a direct injection spark ignition type internal combustion engine, comprising: a fuel injection amount setting device for additional injection for setting a fuel injection amount. 5. A direct injection spark ignition type internal combustion engine having a fuel injection valve for directly injecting fuel into a combustion chamber, performing normal injection before an intake valve close timing, and performing additional injection after an intake valve close timing. A time-synchronous cylinder intake air amount calculating means for calculating a cylinder intake air amount every predetermined time; a time-synchronous fuel injection amount calculation means for calculating a fuel injection amount based on the cylinder intake air amount every predetermined time; A normal injection fuel injection amount setting means for setting a normal injection fuel injection amount at a normal injection timing before the intake valve closing timing based on the fuel injection amount calculated near the normal injection timing before the closing timing; An intake valve closing timing detecting means for detecting an intake valve closing timing; and a value obtained by subtracting a fuel injection amount set for normal injection before the intake valve closing timing from a fuel injection amount calculated near the intake valve closing timing. The intake valve In the additional injection timing of time later
A fuel injection control device for a direct injection spark ignition type internal combustion engine, comprising: an additional injection fuel injection amount setting means for setting a fuel injection amount for the current additional injection. 6. The time-synchronous intake air amount calculating means calculates a cylinder intake air amount by performing a delay process on an intake air amount detected based on a signal from an air flow meter disposed in an intake passage. 3. The method according to claim 2, wherein
The fuel injection control device for a direct injection spark ignition type internal combustion engine according to any one of claims 1 to 5.