JP2003065132A - Fuel injection control device for cylinder direct injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the generation of thermal impact by rapid burning of fuel in a catalyst by an injection of fuel at an expansion stroke (or exhaust stroke) for solving a problem of the catalyst poisoning in a cylinder direct injection type internal combustion engine. SOLUTION: During releasing/controlling the poisoning, the defined number countinj of the number of thinning out is gradually reduced and varied by characteristics corresponding to a load and a rotation of an engine. When the actual number of thinning out count1 does not reach at the defined number countinj, while an injection amount TI1st at an intake stroke is made to a basic amount TI × coefficient part, an injection amount TI2nd at the expansion stroke is made to zero, thereby thinning out the injection. When the actual number of thinning out count t1 reaches at the defined number countinj, the injection amount TI2nd at the expansion stroke is made to TI2nd=(TI-TI×part)×(mincount+1) based on a final value mincount of the defined number countinj and a total injection amount TI=TI×air/fuel ratio correction coefficient COEF to carry out the fuel injection at the expansion stroke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for a direct injection type internal combustion engine, and more particularly to a fuel injection technique for increasing the temperature of a catalyst.

[0002]

2. Description of the Related Art Conventionally, in a cylinder direct injection internal combustion engine, in order to release poisoning by sulfur etc. of a catalyst,
BACKGROUND ART There is known a device that performs a fuel injection between an expansion stroke and an exhaust stroke and burns the injected fuel with a catalyst to raise the temperature of the catalyst (Japanese Patent Laid-Open Nos. 2000-130236 and 2000-054900). (See the official gazette).

[0003]

By the way, as described above, when fuel injection is performed between the expansion stroke and the exhaust stroke, combustion inside the catalyst is rapidly performed, and a temperature difference occurs inside the catalyst. Especially, in the case of a catalyst using a ceramic support having a thin cell thickness, the ceramic support may be cracked.

Therefore, as a method of avoiding the rapid combustion inside the catalyst, the fuel injection amount between the expansion stroke and the exhaust stroke is set small immediately after the start and then gradually increased,
A method of gradually raising the temperature to the required temperature was examined. However, since the injection amount from the expansion stroke to the exhaust stroke is generally small, in order to avoid sudden combustion, it is necessary to set the fuel injection amount below the minimum fuel amount that can be injected at the fuel injection valve. As a result, it is virtually impossible to control the temperature rise by changing the injection amount.

The present invention has been made in view of the above problems, and the fuel injection of a direct injection type internal combustion engine capable of gradually raising the temperature of the catalyst by the fuel injection between the expansion stroke and the exhaust stroke. An object is to provide a control device.

[0006]

Therefore, according to the first aspect of the invention, in an internal combustion engine having a fuel injection valve for directly injecting fuel into a cylinder, exhaust gas is produced by fuel injection between an expansion stroke and an exhaust stroke. A fuel injection control device for raising the temperature of a catalyst interposed in a passage, which is configured such that fuel injection between the expansion stroke and the exhaust stroke is thinned out and the thinning rate is gradually reduced.

According to this structure, the temperature of the catalyst is raised by burning the fuel injected between the expansion stroke and the exhaust stroke with the catalyst, but the fuel is injected every time between the expansion stroke and the exhaust stroke of each cylinder. Instead of performing some injection, the amount of fuel supplied to the catalyst is controlled to be reduced by thinning out without performing some injection, and the thinning rate is gradually reduced (the number of thinned injections is gradually reduced. Decrease) and gradually increase the amount of fuel supplied to the catalyst.

According to the second aspect of the invention, the thinning rate is increased as the engine speed increases.
With such a configuration, the higher the engine speed, the higher the catalyst temperature in general, and the higher the engine rotation speed, the smaller the decimation rate per hour. Therefore, the higher the engine speed, the higher the decimation rate. (Increase the number of thinned injections).

According to a third aspect of the invention, the thinning rate is increased as the engine load increases. According to such a configuration, the catalyst temperature is generally higher as the engine load is larger, and when a certain proportion of the injection amount commensurate with the intake amount is injected between the expansion stroke and the exhaust stroke,
The higher the engine load, the larger the absolute amount of the injection amount in the expansion stroke. Therefore, the higher the engine load, the higher the decimation rate (the greater the number of decimation injections).

According to the fourth aspect of the invention, the initial value, the final value and the reduction rate of the thinning rate are set according to the engine speed and the engine load. According to this configuration,
From the initial value of the thinning rate according to the engine speed and the engine load, the thinning rate is gradually reduced at a decreasing rate according to the rotation / load, and finally to the final value according to the rotation / load.

According to the fifth aspect of the present invention, the fuel injection amount from the expansion stroke to the exhaust stroke is changed according to the thinning rate. According to this configuration, the fuel injection amount between the expansion stroke and the exhaust stroke is changed according to the thinning rate in the fuel injection between the expansion stroke and the exhaust stroke, in other words, the number of thinned injections. , The total injection amount is controlled based on the case where no thinning is performed.

In a sixth aspect of the present invention, the fuel injection amount in the intake stroke or the compression stroke is changed according to the thinning rate, and the rest of the fuel is injected between the expansion stroke and the exhaust stroke. . According to such a configuration, the fuel is injected separately in the injection stroke or the compression stroke and the injection stroke between the expansion stroke and the exhaust stroke, and the amount of fuel injected in the intake stroke or the compression stroke is The thinning rate, in other words, is changed according to the required temperature rise margin to control the amount of oxygen in the combustion exhaust gas by the injection in the intake stroke or the compression stroke.

[0013]

According to the invention of claim 1, by thinning out the injection between the expansion stroke and the exhaust stroke, rapid combustion in the catalyst is avoided and the thinning rate is gradually reduced. This has the effect of ensuring a sufficient temperature rise margin. According to the second aspect of the present invention, the thinning rate is increased as the engine speed increases,
The decimation rate per time can be kept constant, and the temperature rise rate can be controlled to a constant value even if the rotation speed is different, and excessive temperature rise can be avoided when the engine rotation speed is high and the required temperature rise margin is small. Has the effect of

According to the third aspect of the present invention, a large decimation rate is set when the engine load is large and the required temperature rise margin is small, and the injection amount is increased from the expansion stroke to the exhaust stroke as the engine load increases. Since a large thinning rate is set when the temperature increases, there is an effect that an excessive temperature rise is avoided. According to the invention described in claim 4, the variation width of the thinning rate according to the required temperature rise margin can be set, and the temperature rise rate can be controlled to a constant temperature rise rate. There is an effect that the temperature can be raised to a required temperature at a rising rate of.

According to the fifth aspect of the present invention, by changing the injection amount from the expansion stroke to the exhaust stroke in accordance with the thinning rate, it is possible to control to the air-fuel ratio state necessary for releasing the poisoning, for example. Has the effect of becoming. According to the invention described in claim 6, when the required temperature rise amount is large and it is necessary to increase the oxygen amount in the combustion exhaust gas by the injection in the intake stroke or the compression stroke, the oxygen amount can be controlled according to the request. , Securing the amount of oxygen required for fuel combustion in the catalyst,
There is an effect that the temperature rise commensurate with the injection during the expansion stroke to the exhaust stroke can be surely obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram showing a cylinder direct injection internal combustion engine to which a fuel injection control device according to the present invention is applied. A cylinder head 2 of an internal combustion engine 1 shown in FIG. 1 is provided with a fuel injection valve 3 that directly injects fuel into a cylinder, and an ignition plug 4 that spark-ignites an air-fuel mixture.

An intake port 5 is formed in the cylinder head 2 for each cylinder, and air whose flow rate is adjusted by a throttle valve 6 is distributed to the intake port 5 of each cylinder by an intake manifold 7, and the intake port 5 is connected to the intake port 5. A combustion mixture is formed by the air introduced into the cylinder via the fuel and the fuel injected from the fuel injection valve 3. An exhaust port 8 is formed in each cylinder of the cylinder head 2, and exhaust gas from each cylinder is collected by an exhaust manifold 9 connected to the exhaust port 8 and purified by a front catalyst 10 and a rear catalyst 11. And then released into the atmosphere.

An exhaust gas recirculation passage 13 that connects the exhaust manifold 9 and the intake collector portion 12 is provided, and a part of the exhaust gas is recirculated to the intake side through the exhaust gas recirculation passage 13 due to the pressure difference. The exhaust gas recirculation amount is controlled by an exhaust gas recirculation control valve 14 provided in the exhaust gas recirculation passage 13. High-pressure fuel is supplied to the fuel injection valve 3 from the fuel pump 15, and when the fuel injection valve 3 is opened by the injection pulse signal from the control unit 16, a high-pressure fuel in an amount proportional to the valve opening time is generated in the cylinder. Is injected into.

The control unit 16 includes an air flow meter 17 for detecting the intake air amount of the engine 1, a throttle sensor 18 for detecting the opening of the throttle valve 6, a water temperature sensor 19 for detecting the cooling water temperature of the engine 1, and a front. On the upstream side of the catalyst 10, an air-fuel ratio sensor 20 that detects the air-fuel ratio based on the oxygen concentration in the exhaust gas, a catalyst temperature sensor 21 that detects the temperature of the rear catalyst 11, and a rotation signal of the engine 1 are taken out from a crankshaft (not shown). A rotation sensor 22 is provided.

The control unit 16 includes a microcomputer, which outputs an injection pulse signal to the fuel injection valve 3 to control fuel injection based on the detection signals from the various sensors, and the spark plug 4 as well. Control the ignition timing and control the opening degree of the exhaust gas recirculation control valve 14 to control the exhaust gas recirculation amount. The flowchart of FIG. 2 shows a routine for calculating the fuel injection amount (pulse width of the injection pulse signal). In step S201, the fuel injection pulse width TI is calculated as TI = TP × COEF × ALPHA.

TP is the basic injection pulse width corresponding to the theoretical air-fuel ratio calculated from the intake air amount and engine speed, COEF is the air-fuel ratio correction coefficient, and ALPHA is the actual detected by the air-fuel ratio sensor 20. This is an air-fuel ratio feedback correction coefficient for matching the air-fuel ratio with the target air-fuel ratio. Normally, fuel injection with the fuel injection pulse width TI is performed in the intake stroke or compression stroke of each cylinder to form a mixture in the cylinder, but for the purpose of removing poisoning of the catalyst 10 by sulfur or the like, Fuel is injected even during the expansion stroke.

In this embodiment, the injection is performed in the expansion stroke, but the injection timing may be such that the injected fuel directly flows out to the exhaust side between the expansion stroke and the exhaust stroke. The fuel injected in the expansion stroke burns in the catalyst 10, which raises the temperature of the catalyst. When the exhaust air-fuel ratio of the catalyst 10 is leaner than the stoichiometric air-fuel ratio, the N in the exhaust gas
When the NOx absorbent that absorbs Ox and releases the absorbed NOx when the oxygen concentration in the exhaust gas decreases, sulfur is absorbed by the NOx absorbent together with NOx, and this sulfur enriches the air-fuel ratio. However, NOx is not emitted in a reducing atmosphere (exhaust air-fuel ratio rich state)
By heating the absorbent, it is decomposed and released from the NOx absorbent.

The fuel injection control in the expansion stroke for releasing the poisoning will be described with reference to the flowchart of FIG.
The routine shown in the flowchart of FIG. 3 is executed for each injection. In step S301, it is determined whether or not poisoning cancellation control is being performed. The poisoning release control is performed, for example, when the estimated value of the poisoning amount becomes equal to or greater than a predetermined value, or at constant driving time / running distance.

When it is determined in step S301 that the poisoning release control is not in progress, the process proceeds to step S311, and the normal fuel injection for causing the fuel injection to be performed in the intake stroke or the compression stroke based on the fuel injection pulse width TI is performed. . On the other hand, if it is determined in step S301 that the poisoning release control is being performed, the process proceeds to step S302, and the air-fuel ratio correction coefficient C
By determining whether or not OEF is equal to or greater than the predetermined value lambdaSOx, it is determined whether or not the poisoning-releasable rich air-fuel ratio control state is set.

If COEF ≧ lambdaSOx, it is possible to create a reducing atmosphere in which poisoning can be released with the current fuel injection pulse width TI, so that the process bypasses step S303 and proceeds to step S304. On the other hand, when COEF <lambdaSOx, the reducing atmosphere necessary for releasing the poisoning cannot be established, so the routine proceeds to step S303, where the predetermined value lambdaSOx is set to the air-fuel ratio correction coefficient COEF.

In step S304, it is determined whether or not the number of times of thinning out the expansion stroke injection, count1, has reached a prescribed number of times countinj. That is, instead of injecting fuel in each expansion stroke of each cylinder, if fuel injection is performed once in the expansion stroke,
The injection is stopped for the specified number of times countinj, and the specified number of times co
After thinning out only untinj, the injection in the expansion stroke is repeated (see Fig. 6).

In step S304, the thinning-out count count1 has not reached the specified count countinj (count1 <countinj).
When it is determined that the injection pulse width TI1st in the intake stroke or the compression stroke is TI1st = T, the injection in the current expansion stroke is stopped, and the process proceeds to step S308.
I × part is set, in the next step S309, the injection pulse width TI2nd in the expansion stroke is set to 0, and in the next step S310, the thinning-out number count1 is incremented.

On the other hand, in step S304, the number of thinning times co
unt1 has reached the specified number of countinj (count1 ≧ counti
nj), the injection is performed in the expansion stroke this time, so the process proceeds to step S305, and the injection pulse width TI1st in the intake stroke or the compression stroke is set to TI1st = TI ×
Then, in the next step S306, the injection pulse width TI2nd in the expansion stroke is set to TI2nd = (TI-TI
Xpart) × (mincount + 1), and further, in the next step S307, the thinning-out number count1 is cleared.

The specified number of times of thinning, countinj, is set to be gradually decreased from the initial value and the final value mincou
It changes to nt, whereby the thinning rate is gradually reduced (see FIG. 6). The injection pulse width T
The coefficient part used in the calculation of I1st is a value slightly smaller than 1.0, so that the fuel injected in the intake stroke or the compression stroke becomes lean when the fuel is injected in the expansion stroke to burn in the catalyst 10. To secure oxygen.

Further, when it is necessary to inject a large amount of fuel in the expansion stroke to burn a large amount of fuel in the expansion stroke because the required temperature rise margin is large, the combustion time of the fuel injected in the intake stroke or the compression stroke is increased. Need to be leaner in. The required temperature rise amount is the specified number of thinning times co
It can be judged from the final value mincount of untinj, and the final value mincount
Since it is determined that the required temperature rise amount is larger as the value of the above is smaller, the coefficient part is set to a smaller value as the final value mincount is smaller.

However, if the final value mincount is given as a fixed value, the coefficient part is also a fixed value. The injection pulse width TI2nd in the expansion stroke is based on the remainder obtained by subtracting the injection pulse width TI1st = TI × part in the intake stroke or compression stroke from the normal injection pulse width TI.
It is set by multiplying the basic value by a value obtained by adding 1 to the final value mincount of the thinning times.

TI2nd = (TI-TI × part) × (mincount + 1) For example, if the final value mincount of decimation is 1, twice the basic value will be injected, which is the same as the case without decimation as a total. When a certain amount of fuel is injected and the final value of thinning, mincount, is reached and the temperature required to release poisoning is reached, the rich exhaust air-fuel ratio required to release poisoning can be obtained as a total.

As a simplified control, during the poisoning release control, the air-fuel ratio correction coefficient COEF is set to 1, the injection pulse width TI1st in the intake or compression stroke is set to TI1st = TI,
The injection pulse width TI2nd in the expansion stroke is given by TI2nd = TI ×
It can also be afterinj (afterinj is a constant).
As described above, if the expansion stroke injection is performed by thinning while gradually reducing the thinning rate, as shown in FIG. 7, the temperature of the central portion of the catalyst is lower than that when no thinning is performed. Since the temperature rises gradually, it is possible to avoid cracking of the carrier due to heat shock.

The flow chart of FIG. 4 shows the first embodiment of the setting control of the specified thinning count countinj, which is executed at regular time intervals. In step S401,
It is determined whether or not the poisoning cancellation control is being performed, and if the poisoning cancellation control is not being performed, the processing ends. On the other hand, when it is determined in step S401 that the poisoning release control is being performed, the process proceeds to step S402, and it is determined whether or not it is immediately after the start of the poisoning release control.

Immediately after the poisoning release control is started, the preset initial value countstart is set in the specified number of times countinj. If it is determined in step S402 that the poisoning release control has not just started, the process proceeds to step S404.
It is determined whether the specified number of times countinj is less than or equal to the previously stored final value mincount.

Here, when countinj> mincount, the process proceeds to step S406, and the specified number of times countinj is set to be decreased by the previously stored decrease correction value (reduction rate) decount. As a result of the decrease control in step S406, when it is determined in step S404 that countinj ≦ mincount, the process proceeds from step S404 to step S405, and the specified value mincount is set to the specified number of times countinj.

By the above processing, the specified number of countinj
Is the final value mincount at a constant speed from the initial value countstart
Will be reduced to. In the flowchart of FIG. 4 described above, the injection in the expansion stroke is thinned out based on the constant number of thinning-out regardless of the operating condition of the engine 1, but the number of thinning-out can be changed according to the operating condition. More preferable, counti specified number of times counti according to operating conditions
A second embodiment for controlling the setting of nj will be described with reference to the flowchart of FIG.

In step S501, the engine load and engine speed are read. The engine load can be represented by the basic injection pulse width TP. Next step S502
Then, it is determined whether or not the poisoning cancellation control is being performed, and if the poisoning cancellation control is not being performed, the processing is ended as it is. On the other hand, when the poisoning release control is being performed, the process proceeds to step S503, and the basic value mincountrev of the final value of the number of times of thinning is set according to the engine rotation speed.

As shown in FIG. 8, the basic value mincountrev is set to a larger value as the engine speed increases.
As shown in FIG. 9, when the engine rotation speed is high, the catalyst temperature is generally high, and the decimation rate per hour becomes smaller as the rotation speed becomes higher, and the temperature rise due to the injection in the expansion stroke is large. Therefore, the higher the engine speed, the lower the need for injection in the expansion stroke. Therefore, the higher the engine speed, the larger the basic value mincountrev is set (higher decimation rate).

In the next step S504, the load correction value minloadhosei, which is the final value of the number of times of thinning, is set according to the engine load at that time. The load correction value minloadhosei is
As shown in FIG. 10, the higher the engine load, the larger the value set. As shown in FIG. 11, when the engine load is high, the catalyst temperature is generally high, and when the engine load is high, the absolute value of the injection amount in the expansion stroke becomes large, and the injection 1 Since the temperature rise per turn becomes large, the load correction value minloadhosei is set to a larger value (higher thinning rate) as the engine load increases.

In step S505, the final value mincount of the number of times of thinning is calculated as mincount = mincountrev × minloadhosei. In step S506, it is determined whether or not the poisoning cancellation control has just started. If it is immediately after the start, the process proceeds to step S507, and is the basic value of the initial value of the number of thinning-outs.
Set stcountrev according to the engine speed.

Although the basic value stcountrev of the initial value is larger than the basic value mincountrev of the final value, a larger value (higher decimation rate) becomes higher as the engine speed increases, like the basic value mincountrev of the final value. Is set to (Fig. 8
reference). In the next step S508, the load correction value stloadhosei, which is the initial value of the number of times of thinning, is set according to the engine load at that time.

The load correction value stloadhosei of the initial value is
Although the value is larger than the final value of the load correction value minloadhosei, it is set to a larger value (higher thinning rate) as the engine load is higher, similarly to the final value of the load correction value minloadhosei (see FIG. 10). In step S509, the initial setting is performed by setting stcountrev × stloadhosei in the specified number of times of thinning, countinj.

When it is determined in step S506 that it is not immediately after the start, the process proceeds to step S510, and it is determined whether or not the specified number of thinnings, countinj, is equal to or less than the final value mincount. When countinj ≦ mincount, the process proceeds to step S511, and the final value mincount is set to the specified number of times thinning out countinj.

On the other hand, if countinj> mincount, the process proceeds to step S512 and the reduction rate basic value decountr of the thinning rate.
Set ev according to the engine speed. The basic value of the reduction rate
As shown in FIG. 12, decountrev is set to a smaller value as the engine rotation speed is higher. When the engine rotation speed is high, the required temperature rise margin of the catalyst is small, and therefore, the necessary and sufficient temperature rise can be obtained by gradually decreasing the number of thinning-outs while maintaining a large number.

On the other hand, when the engine rotation speed is low, it is necessary to quickly reduce the thinning-out rate in order to secure a large required temperature rise margin in the catalyst while suppressing the initial rapid temperature rise with a large thinning-out rate. Therefore, the reduction rate basic value de
A large value is required for countrev. Next step S
In 513, the reduction rate load correction value deloadhosei of the thinning rate
Is set according to the engine load.

The decrease rate load correction value deloadhosei is set to a smaller value as the engine load is higher, as shown in FIG. When the engine load is high, the required temperature rise of the catalyst is small. Therefore, the necessary and sufficient temperature rise can be obtained by gradually changing the number of thinning-outs with a large number.
On the other hand, when the engine load is low, it is necessary to quickly reduce the thinning rate in order to secure a large necessary temperature rise margin in the catalyst while suppressing the initial rapid temperature rise with a large thinning rate. A large value is required as the rate load correction value deloadhosei.

In step S514, the thinning reduction rate deco
Calculate unt as decount = decountrev x deloadhosei. In step S515, the prescribed number of thinnings, countinj, is reduced by the thinning reduction rate decount.

As described above, the specified number of thinnings countinj
If the initial value, the final value, and the rate of decrease of (thinning rate) are set according to the engine speed and engine load, the necessary temperature rise margin can be obtained while avoiding heat shock due to rapid combustion. In addition, it is possible to avoid excessive temperature rise. In addition, in the above-described embodiment, when the injection is performed in the expansion stroke once, the injection is thinned by the specified number of countinj, and the expansion stroke injection is performed only once after the thinning, and the specified number of countinj of the thinning is gradually performed. However, the number of thinning-outs per predetermined number of injections is changed so that, for example, at the start, the injections are stopped eight times in succession after two continuous injections, and then the number of continuous injections is gradually increased. In response to this, the number of thinning-outs is gradually reduced, and finally, the number of continuous injections and the number of thinning-outs are relatively increased or decreased such that the number of injections is thinned out only twice after eight consecutive injections. It can be configured to.

In the above embodiment, the catalyst is heated only by the fuel injection in the expansion stroke (exhaust stroke), but it may be combined with the ignition timing retard control or the exhaust gas recirculation stop control. be able to.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an internal combustion engine according to an embodiment.

FIG. 2 is a flowchart showing calculation of a fuel injection amount in the embodiment.

FIG. 3 is a flowchart showing injection control for releasing poisoning in the embodiment.

FIG. 4 is a flowchart showing a first embodiment of thinning-out frequency setting.

FIG. 5 is a flowchart showing a second embodiment of setting the number of thinning-outs.

FIG. 6 is a time chart showing the correlation between intake stroke injection and expansion stroke injection in the embodiment.

FIG. 7 is a time chart for explaining the effect of the embodiment.

FIG. 8 is a diagram showing a correlation between an engine rotation speed and an initial value / final value of the number of times of thinning according to the embodiment.

FIG. 9 is a diagram showing a correlation between engine speed and catalyst temperature.

FIG. 10 is a diagram showing a correlation between an engine load and an initial value / final value of the number of times of thinning according to the embodiment.

FIG. 11 is a diagram showing a correlation between engine load and catalyst temperature.

FIG. 12 is a diagram showing a correlation between an engine speed and a reduction rate of the number of times of thinning according to the embodiment.

FIG. 13 is a diagram showing a correlation between an engine load and a reduction rate of the number of thinning-outs in the embodiment.

[Explanation of symbols]

1 ... Internal combustion engine 2 ... Cylinder head 3 ... Fuel injection valve 4 ... Spark plug 5 ... Intake port 6 ... Throttle valve 7 ... Intake manifold 8 ... Exhaust port 9 ... Exhaust manifold 10 ... Front catalyst 11 ... Rear catalyst 16 ... Control unit 17 ... Air flow meter 18 ... Throttle sensor 19 ... Water temperature sensor 20 ... Air-fuel ratio sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G084 BA13 BA15 CA03 CA04 CA09                       DA19 DA37 EA11 EB09 EB22                       EC01 EC03 FA00 FA07 FA10                       FA20 FA29 FA33                 3G301 JA33 KA06 KA23 MA11 MA19                       MA26 NC04 PA01Z PA11Z                       PD02Z PD12Z PE01Z PE08Z

Claims (6)

[Claims] 1. An internal combustion engine having a fuel injection valve for directly injecting fuel into a cylinder, in which fuel injection control is performed to raise a temperature of a catalyst interposed in an exhaust passage by fuel injection between an expansion stroke and an exhaust stroke. A fuel injection control device for a direct injection type internal combustion engine, comprising: a device for thinning fuel injection between the expansion stroke and the exhaust stroke; and gradually reducing a thinning ratio. 2. The fuel injection control device for a direct injection type internal combustion engine according to claim 1, wherein the thinning rate is increased as the engine speed increases. 3. The fuel injection control device for a direct injection type internal combustion engine according to claim 1, wherein the thinning rate is increased as the engine load is increased. 4. The fuel injection of a direct injection type internal combustion engine for a cylinder according to claim 1, wherein an initial value, a final value and a reduction rate of the thinning rate are set according to an engine speed and an engine load. Control device. 5. The in-cylinder direct injection according to claim 1, wherein the fuel injection amount between the expansion stroke and the exhaust stroke is changed according to the thinning rate. Injection control device for internal combustion engine. 6. A fuel injection amount in an intake stroke or a compression stroke,
The in-cylinder direct injection internal combustion engine according to any one of claims 1 to 5, characterized in that the remaining portion of the fuel is injected between the expansion stroke and the exhaust stroke by changing according to the thinning rate. Fuel injection control device.