JP2000120432A - Exhaust emission control device for direct injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently early activate catalysts for purifying an exhaust gas without deteriorating emission in a direct injection type internal combustion engine. SOLUTION: An exhaust emission control device for a direct injection type internal combustion engine for injecting fuel into a direct combustion chamber 11 and for carrying out lean air fuel ratio operation under required operating conditions is provided with: a fuel injection valve 17 capable of injecting fuel and pressurized air from a common nozzle hole into the direct combustion chamber 11, catalysts 22, 23 for purifying an exhaust gas placed in an exhaust passage 15, a temperature elevation determining means for determining conditions for elevating the temperature of the catalysts 22, 23 for purifying exhaust, and an additional fuel injection control means for injecting the fuel and the pressurized air from the fuel injection valve 17 in the course of an expansion stroke or an exhaust stroke under the conditions for elevating the temperature of the catalysts for purifying the exhaust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for a direct injection internal combustion engine which injects fuel directly into a combustion chamber, and more particularly to a technique for early activation of an exhaust gas purifying catalyst.

[0002]

2. Description of the Related Art An exhaust gas purifying catalyst is provided in an exhaust passage for purifying exhaust gas of an engine such as an internal combustion engine for an automobile. If the temperature of the catalyst is not increased to a predetermined value or more, the catalyst may be used. Does not exhibit the desired purification ability.

For this reason, for example, Japanese Patent Application Laid-Open No. 8-296485
Japanese Patent Application Laid-Open Publication No. H11-157, discloses a technique in which a fuel injection valve is operated again after an expansion stroke to add additional fuel to a combustion chamber in a four-cycle engine. This is because, when the catalyst is determined to be inactive, such as after the engine is started, by the catalyst activation state determination means or the like, additional fuel is injected after the expansion stroke, and the additional fuel is burned to raise the catalyst temperature. By doing so, the activity of the catalyst is achieved.

[0004]

However, in the above-mentioned prior art, since unburned fuel is supplied to the catalyst from inside the cylinder, the following problems can be considered. In other words, the condition for additional fuel injection is when the catalyst is inactive,
Immediately after the start of the injection of additional fuel, a part of the unburned fuel additionally injected is oxidized by the catalyst and contributes to the temperature rise of the catalyst, but most of the unburned fuel is not oxidized by the catalyst. There is a concern that the gas will pass through the catalyst and be discharged without being purified.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems while ensuring good combustion of an additional fuel, and to efficiently and early activate an exhaust gas purifying catalyst in a direct injection internal combustion engine. .

[0006]

A first aspect of the present invention is a common exhaust gas purifying apparatus for a direct injection type internal combustion engine which injects fuel directly into a combustion chamber and performs a lean air-fuel ratio operation under required operating conditions. A fuel injection valve capable of directly injecting fuel and pressurized air from a nozzle into a combustion chamber; an exhaust purification catalyst disposed in an exhaust passage; and a temperature rise determination means for determining a condition for raising the temperature of the exhaust purification catalyst. And an additional fuel injection control means for injecting additional fuel and pressurized air from the fuel injection valve during the expansion stroke or the exhaust stroke when the temperature of the exhaust purification catalyst is to be raised.

According to a second aspect of the present invention, there is provided an exhaust gas purifying apparatus for a direct injection type internal combustion engine which injects fuel directly into a combustion chamber and performs a lean air-fuel ratio operation under required operating conditions. A fuel injection valve capable of injecting air directly into the combustion chamber, main injection control means for injecting main fuel from the fuel injection valve during a compression stroke to perform stratified combustion, and an exhaust purification catalyst disposed in an exhaust passage A temperature rise determining means for determining a condition for raising the temperature of the exhaust gas purification catalyst; and additional fuel and heat during the expansion stroke or the exhaust stroke from the fuel injection valve when the temperature of the exhaust gas purification catalyst is to be raised. Additional fuel injection control means for injecting compressed air is provided.

[0008] In a third aspect based on the first and second aspects, the temperature rise judging means raises the temperature of the exhaust gas purification catalyst when the activity of the exhaust gas purification catalyst has not reached a predetermined activity level. It is determined that the condition to be fulfilled is satisfied.

In a fourth aspect based on the first and second aspects, the exhaust purification catalyst includes a catalyst for absorbing and releasing NOx in the exhaust gas in accordance with an air-fuel ratio of the exhaust gas flowing into the exhaust gas purification catalyst. The temperature rise determining means determines that the condition for raising the temperature of the exhaust gas purification catalyst is satisfied when the SOx absorbed by the exhaust gas purification catalyst is to be released.

In a fifth aspect based on the first and second aspects, the additional fuel injection control means injects pressurized air from the fuel injection valve prior to the injection of the additional fuel.

In a sixth aspect based on the first and second aspects, the additional fuel injection control means injects additional fuel and pressurized air from a fuel injection valve, and then further injects only pressurized air. .

In a seventh aspect based on the first and second aspects, the additional fuel injection control means starts the injection of pressurized air from the fuel injection valve prior to the injection of the additional fuel, thereby injecting the additional fuel. The injection of the pressurized air is ended on the retard side from the end.

In an eighth aspect based on the first, second, sixth, and seventh aspects, the additional fuel injection control means includes means for controlling an injection amount of pressurized air from a fuel injection valve to a catalyst temperature and an engine operating temperature. Is decreased in accordance with the rise of or the elapsed time from the start of the control.

In a ninth aspect based on the first, second, sixth, and seventh aspects, the additional fuel injection control means includes means for controlling the timing of starting injection of pressurized air from the fuel injection valve with the catalyst temperature and engine operation. The angle is retarded according to the temperature rise or the elapsed time from the start of the control.

According to a tenth aspect, in the first aspect, there is provided main injection control means for injecting only main fuel from a fuel injection valve during a compression stroke or an intake stroke. When the temperature of the catalyst for use should be raised,
The additional fuel injection control means injects only pressurized air from the fuel injection valve during an expansion stroke or an exhaust stroke.

[0016]

According to the first aspect, when the temperature of the catalyst is to be raised, the flow of the combustion gas in the combustion chamber is enhanced by the injection of the pressurized air, and the mixing of the combustion gas and the additional fuel is promoted. At the same time, the oxidation reaction of the fuel on the catalyst is performed well. Therefore, when the catalyst is inactive, the exhaust gas temperature and the catalyst temperature can be quickly increased without deteriorating the emission due to the injection of the additional fuel, and the catalyst can be quickly activated efficiently.

According to the second aspect of the invention, at the time of the lean air-fuel ratio operation by the stratified charge combustion, the mixture of the additional fuel, the combustion gas layer and the air layer is promoted, and good combustion of the additional fuel is ensured. The exhaust temperature and catalyst temperature are quickly raised without deteriorating emissions due to fuel injection,
Early activation of the catalyst can be performed efficiently.

According to the third and fourth aspects of the present invention, the catalyst can be activated accurately, and SOx contained in the exhaust gas and absorbed by the catalyst together with NOx can be properly treated.

According to the fifth and sixth aspects, the additional fuel is injected after the gas flow in the combustion chamber is promoted, so that better combustion of the additional fuel can be ensured. By injecting additional fuel into the formed air layer and further injecting pressurized air, oxygen can be reliably present around the additional fuel, and better combustion of the additional fuel can be ensured. .

According to the seventh aspect, a fuel injection valve having a very low response is not required, and the cost can be reduced. Also, depending on the flow of combustion gas, the degree of mixing with air, etc.,
By setting the injection end timing of the pressurized air to the retard side, the effect of increasing the temperature of exhaust gas can be enhanced.

According to the eighth and ninth aspects, the temperature of the catalyst can be optimally raised in accordance with the rise of the catalyst temperature and the operating temperature of the engine or the elapsed time from the start of the control, and the control can be smoothly shifted to the normal control. .

According to the tenth aspect, it is easy to control the injection of fuel and pressurized air from the fuel injection valve.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 10 denotes an engine body;
Denotes a combustion chamber, 12 denotes an intake valve, 13 denotes an intake passage, 14 denotes an exhaust valve, 15 denotes an exhaust passage, 16 denotes a spark plug, and 17 denotes a fuel injection valve for directly injecting fuel and pressurized air into the combustion chamber 11. .

The fuel injection valve 17 is capable of injecting fuel and pressurized air from a common injection port (for example, see Japanese Patent Application Laid-Open No. 9-126100). In the fuel injection valve 17, the fuel which is sucked from the fuel tank 18 into the fuel inlet and adjusted to a predetermined high pressure by the fuel pump 19 is sucked into the air inlet from the intake passage 13 downstream of the intake air amount sensor 32 and is moved by the air pump 20. The pressurized air compressed to a predetermined high pressure is guided, and the fuel and the pressurized air can be independently injected.

An electronically controlled throttle 2 is provided in the intake passage 13.
1 is provided. The opening of the electronic control throttle 21 is controlled by a control unit 30 described later so as to obtain an intake air amount corresponding to the operating conditions of the engine.

In the exhaust passage 15, as an exhaust gas purifying catalyst, N in the exhaust gas according to the air-fuel ratio of the exhaust gas flowing into the exhaust passage 15.
A lean NOx catalyst 22 for absorbing and releasing Ox and a three-way catalyst 23 downstream thereof are interposed. In the lean NOx catalyst 22 absorbs NOx in a lean atmosphere, and reduces NOx which has been absorbed in a rich atmosphere is discharged as N _2. In the three-way catalyst 23, oxidation of HC and CO and reduction of NOx are simultaneously performed in a stoichiometric (stoichiometric air-fuel ratio) state.

On the upstream side of the lean NOx catalyst 22, a first air-fuel ratio sensor 24 for detecting the air-fuel ratio of exhaust gas over a wide range is provided.
However, a second air-fuel ratio sensor 25 is installed between the lean NOx catalyst 22 and the three-way catalyst 23. The lean NOx catalyst 22 has a catalyst temperature sensor 26 for detecting the temperature of the catalyst 22.
Is installed. In addition to the catalyst temperature sensor 26, a temperature sensor for detecting the temperature of the three-way catalyst 23 may be provided. These signals are input to the control unit 30.

As means for detecting the operating conditions of the engine, a rotational speed sensor (crank angle sensor) 31 for detecting the engine speed and crank angle, an intake sensor 32 for detecting the intake air amount of the engine, an accelerator opening , A water temperature sensor 34 for detecting the temperature of the engine cooling water, and the like are also input to the control unit 30.

On the basis of these sensor signals, the control unit 30 controls the fuel injection valve 17 so as to perform a lean operation (compression stroke injection) and a stoichiometric operation (intake stroke injection) in accordance with normal control, that is, operating conditions. 1
The fuel injection and the pressurized air injection of No. 7 are controlled, and the activation control of the exhaust purification catalysts 22 and 23 is performed.

In this case, as shown in FIG. 2, the compression stroke injection lean operation is performed in the low / medium load region of the engine according to the engine speed and torque (determined from the engine speed, accelerator opening, intake air amount, etc.). The intake stroke injection stoichiometric operation range is set in the high load range of the engine.

In the intake stroke injection stoichiometric operation region, as shown in FIG. 3, fuel is injected in the intake stroke, fuel and air are premixed in the entire combustion chamber 11, and homogeneous combustion with a mixture near the stoichiometric air-fuel ratio is performed. Will be At this time, by injecting the pressurized air with some delay, atomization of the fuel is promoted, and good mixing of the spray and the air is ensured.

In the compression stroke injection lean operation region, as shown in FIG. 3, fuel is injected in the latter half of the compression stroke, and a combustible mixture layer is formed only near the ignition plug 16 at the compression top dead center. The stratified combustion of the air-fuel mixture having a super lean air-fuel ratio is performed. Also at this time, the fuel is atomized by injecting the pressurized air with some delay. In the latter half of the compression stroke, the differential pressure between the combustion chamber and the pressurized air becomes small, so that spraying of the pressurized air does not cause excessive spraying, and good stratification is ensured.

Since the fuel is atomized by the injection of the pressurized air, the unburned fuel due to the fuel adhering to the cylinder bore and the piston crown is reduced, and the unburned component discharged is suppressed.

Next, the contents of the activation control of the exhaust gas purifying catalysts 22 and 23 will be described with reference to the flowcharts of FIGS.

As shown in FIG. 4, in step 1, the temperature Ta of the catalyst 22 is read, and it is determined whether the temperature Ta of the catalyst 22 is lower than a predetermined value.

When the temperature Ta of the catalyst 22 is equal to or lower than a predetermined value,
It is determined that the catalyst 22 (and 23) is inactive, and the control enters the catalyst temperature increase control in step 2.

When the temperature Ta of the catalyst 22 is equal to or higher than a predetermined value,
In step 4, a catalyst deactivation condition when the temperature Ta of the catalyst 22 is equal to or higher than a predetermined value is determined.

In such a case, the sulfur content in the fuel is absorbed by the NOx catalyst 22 and the NOx cannot be effectively purified, or the catalysts 22 and 23 and the exhaust gas May have decreased contact area.

For example, as shown in FIG. 6, the NOx emission amount of the engine can be obtained from the operating conditions (compression stroke injection lean operation region, intake stroke injection stoichiometric operation region). By comparing with the measured value of the air-fuel ratio sensor 25 downstream of the catalyst 22,
Can be determined whether it is inactive due to sulfur poisoning or smoke poisoning. That is, when the difference between the detected value of the air-fuel ratio sensor 25 and the NOx emission amount is equal to or greater than a predetermined value, it is determined that the NOx absorption rate of the catalyst 22 is reduced due to sulfur poisoning or smoke poisoning and the catalyst 22 is in an inactive state. I do. The measured value of the air-fuel ratio sensor 24 upstream of the catalyst 22 and the air-fuel ratio sensor 2
The inactive state of the catalyst 22 may be determined by comparing the measured value of No. 5 with the measured value of No. 5.

When the catalyst is inactive, the control proceeds to step 5 for increasing the temperature of the catalyst. When the catalyst is not inactive, normal control is performed in step 6.

The control for raising the temperature of the catalyst is performed in step 1 as shown in FIG.
In step 1, the engine speed, accelerator opening, intake air amount, and the like are read, and it is determined whether the engine speed and torque are equal to or greater than predetermined values.

When the engine speed and torque are equal to or higher than the predetermined values, the operating region is in the intake stroke injection stoichiometric operation region of FIG. 2 and the exhaust gas temperature is high. Is determined to automatically raise the temperature, and the process returns.

On the other hand, when the engine speed and torque are equal to or higher than the predetermined values, the operation region is in the compression stroke injection lean operation region of FIG.
That is, in addition to the normal control of injecting fuel and pressurized air from the fuel injection valve 17 in the latter half of the compression stroke, control is performed so as to inject a predetermined amount of additional fuel and additional pressurized air during the expansion stroke or the exhaust stroke.

In the injection of the additional fuel and the additional pressurized air, the additional pressurized air is injected prior to the injection of the additional fuel as shown in FIG. I do.

The amount of additional fuel and the amount of additional pressurized air are determined based on the engine speed and torque. In this case, the additional fuel amount and the additional pressurized air amount may be set so as to increase as the temperature Ta of the catalyst 22 and the cooling water temperature Tw of the engine are lower.

Then, the injection control is continued twice in step 16 until the temperature Ta of the catalyst 22 rises and reaches a predetermined temperature at which the sulfur poisoning or the smoke poisoning is released. In step 17, the injection control is ended twice and the control returns to the normal control. The engine coolant temperature T
The two-time injection control may be continued until w is equal to or more than a predetermined value or the difference between the detection value of the air-fuel ratio sensor 25 and the NOx emission amount becomes smaller than the predetermined value.

With this configuration, when the temperature of the exhaust purification catalysts 22 and 23 is low, such as immediately after the start of the engine, and when the cooling water temperature of the engine is low and the catalysts 22 and 23 are inactive, the fuel injection valve 17 , Fuel and pressurized air are injected in the latter half of the compression stroke, and a predetermined amount of additional fuel and additional pressurized air are injected during the expansion stroke or the exhaust stroke (compression stroke injection lean operation region).

By the injection of the additional pressurized air, the flow of the combustion gas in the combustion chamber 11 during the expansion stroke or the exhaust stroke is enhanced, and the additional fuel is widely diffused into the combustion chamber 11.
For this reason, mixing of the combustion gas and the additional fuel is promoted, and good combustion of the additional fuel is obtained.
The unevenness in the fuel concentration of the exhaust gas flowing into the catalyst is also reduced, and the oxidation reaction of the fuel on the catalysts 22 and 23 is also performed favorably.

In particular, when stratified combustion is performed by injecting fuel (main fuel) during the compression stroke, the combustion gas and air often exist in a stratified form in the combustion chamber 11 even after the combustion. Simply injecting the additional fuel increases the amount of fuel that does not come into contact with the combustion gas that becomes the ignition source, resulting in poor ignitability. Further, if the combustion gas and air which have been stratified in the combustion chamber 11 flow into the catalysts 22 and 23 as they are, a part of the fuel injected into the combustion gas layer is also contained in the combustion gas. After reacting with the slight amount of oxygen remaining in the catalyst, much of it flows into the catalysts 22 and 23 in a state of being wrapped in the combustion gas, and may not be reacted on the catalysts 22 and 23 and may be discharged as it is. However, by agitating the gas in the combustion chamber 11 by the injection of the pressurized air, the mixing of the combustion gas layer and the air layer proceeds, and the opportunity for the additional fuel to come into contact with both the combustion gas and the air is obtained. Is increased. In addition, the gas discharged from the combustion chamber 11 is homogenized, and the reaction on the catalysts 22 and 23 is performed well.

Further, since the additional pressurized air is injected prior to the additional fuel, that is, the additional fuel is injected after the gas flow in the combustion chamber 11 is promoted, better combustion of the additional fuel is obtained. Further, the additional fuel is injected into the air layer formed by the injection of the pressurized air, and the pressurized air is further injected, so that oxygen can be reliably present around the additional fuel, and Better combustion is obtained.

As described above, good combustion of the additional fuel is ensured, and therefore, the exhaust gas purifying catalysts 22 and 23 are provided.
Is inactive and when the engine coolant temperature is low, the injection of additional fuel does not deteriorate the emission,
The exhaust gas temperature and the temperature of the exhaust gas purification catalysts 22 and 23 can be quickly increased, and the early activation of the exhaust gas purification catalysts 22 and 23 is efficiently performed.

Also, when the catalysts 22 and 23 are inactive due to sulfur poisoning or smoke poisoning, as described above, additional fuel and additional compressed air are supplied from the fuel injection valve 17 during the expansion stroke or the exhaust stroke. It is injected. Therefore, the catalysts 22 and 23 can be regenerated to keep the catalysts 22 and 23 in a good state at all times, and high purification efficiency of the catalysts 22 and 23 can be maintained.

FIG. 7 shows another embodiment of the present invention. In the above-described embodiment, additional pressurized air is injected twice during the expansion stroke or the exhaust stroke. The injection period of the compressed air is lengthened, and the injection is performed once.

Therefore, a fuel injection valve having such a high response is not required, and the cost can be reduced.

FIG. 8 shows another embodiment of the present invention, in which the injection of the additional pressurized air is performed once and the injection period of the additional pressurized air is retarded with respect to the injection of the additional fuel. To make it longer.

This is because the injection period of the additional pressurized air is extended to the retard side in accordance with the flow of the combustion gas, the degree of mixing with air, and the spray characteristics in the expansion stroke or the exhaust stroke, thereby reducing HC. And the effect of increasing the temperature of the exhaust gas is increased.

FIG. 9 shows another embodiment of the present invention, in which the injection timing of the additional pressurized air is changed according to the temperature of the catalyst 22.

This is because, when there is a request to raise the temperature of the catalysts 22 and 23 as shown in FIG. The amount (injection pulse) and the injection amount (injection pulse) of the additional fuel and the additional pressurized air in the expansion stroke or the exhaust stroke are determined.

In steps 25 and 26, the temperature Ta of the catalyst 22 is compared with a predetermined value [1] and a predetermined value [2] (predetermined value [1] <predetermined value [2]).

When the temperature Ta of the catalyst 22 is equal to or lower than the predetermined value [1], the injection timing of the additional pressurized air is set earlier in step 27.

When the temperature Ta of the catalyst 22 is equal to or higher than the predetermined value [1] and equal to or lower than the predetermined value [2], in step 28, the injection timing of the additional pressurized air is set to a late timing.

In this case, as shown in FIG. 10, when the temperature Ta of the catalyst 22 is lower than the predetermined values [1] and [2], the injection timing of the additional pressurized air is set in proportion to the temperature Ta. Is also good.

If the temperature Ta of the catalyst 22 is equal to or higher than the predetermined value [2], the injection of the additional pressurized air is stopped in step 29.

That is, when the temperature of the catalyst 22 is low, the injection of the additional pressurized air is accelerated, the combustion of the additional fuel is sufficiently accelerated, and the temperature of the catalysts 22 and 23 is increased. Thus, when the amount of additional fuel is large, the temperature of the catalysts 22 and 23 can be accurately increased without discharging unburned fuel.

When the temperature of the catalyst 22 is not so low or rises to some extent, the injection of the additional pressurized air is delayed so that the unburned fuel reaches a position close to the catalysts 22 and 23, Burn near 22 and 23.
Thereby, the temperature of the catalysts 22 and 23 can be efficiently increased.

When the temperature of the catalyst 22 is high or high, the injection of the additional pressurized air is stopped, so that the fuel droplets reach the catalysts 22 and 23,
By burning with the catalysts 22 and 23, the temperature of the catalysts 22 and 23 can be increased while reducing additional fuel.

On the other hand, means for detecting the engine temperature and the exhaust gas temperature in addition to the operating temperature of the engine, that is, the engine cooling water temperature, are provided, and the injection timing of the additional pressurized air is controlled by increasing the catalyst temperature and the operating temperature of the engine or by two degrees The angle may be retarded according to the elapsed time from the start of the injection control. In this way, the temperatures of the catalysts 22 and 23 can be optimally increased.

Further, in addition to the injection timing of the additional pressurized air, the injection amount is set in accordance with the catalyst temperature and the operating temperature of the engine. Accordingly, the temperature of the catalysts 22 and 23 can be accurately increased. Further, it is possible to smoothly shift to the normal control.

When the temperature of the catalysts 22 and 23 is to be increased, only the main fuel is injected from the fuel injection valve 17 during the compression stroke or the intake stroke, and the fuel is injected from the fuel injection valve 17 during the expansion stroke or the exhaust stroke. Alternatively, only additional pressurized air may be injected. In this case, the main fuel and the additional pressurized air increase. This makes it easy to control the injection of fuel and pressurized air from the fuel injection valve 17.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment.

FIG. 2 is a characteristic diagram showing an intake stroke injection stoichiometric operation region and a compression stroke injection lean operation region.

FIG. 3 is a characteristic diagram showing injection timing and the like.

FIG. 4 is a flowchart showing control contents.

FIG. 5 is a flowchart showing control contents.

FIG. 6 is a characteristic diagram showing NOx emissions of an engine.

FIG. 7 is a characteristic diagram illustrating injection timing and the like according to another embodiment.

FIG. 8 is a characteristic diagram showing injection timing and the like according to another embodiment.

FIG. 9 is a flowchart showing control contents according to another embodiment.

FIG. 10 is a characteristic diagram showing an example of setting the injection timing of pressurized air.

[Explanation of symbols]

 Reference Signs List 10 engine body 11 combustion chamber 17 fuel injection valve 19 fuel pump 20 air pump 21 electronic control throttle 22 lean NOx catalyst 23 three-way catalyst 24, 25 air-fuel ratio sensor 26 catalyst temperature sensor 30 control unit 31 rotation speed sensor (crank angle sensor) 32 Intake sensor 33 Accelerator opening sensor 34 Cooling water temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F02D 41/02 301 F02D 41/02 301A 41/04 305 41/04 305A 41/34 41/34 H 45 / 00 312 45/00 312R F02M 67/02 F02M 67/02 F term (reference) 3G066 AA02 AA04 AB02 AD12 BA02 BA03 BA14 BA25 BA26 CA21 CC46 DA04 DA09 DB01 DB04 DB07 DB12 DC04 DC09 DC14 DC24 3G084 AA03 BA09 BA10 BA13 BA15 BA26 BA26 DA10 DA27 FA07 FA10 FA20 FA26 FA30 FA33 3G091 AA02 AA12 AA17 AA24 AB03 AB06 BA03 BA04 BA11 BA14 BA15 BA19 BA32 BA33 CA18 CA22 CB02 CB03 CB08 DB10 EA01 EA05 EA07 EA16 EA18 EA30 EA31 EB07 FB07 FB07 HA42

Claims (10)

[Claims] 1. Injecting fuel directly into a combustion chamber,
In the exhaust gas purification system of a direct injection type internal combustion engine that performs lean air-fuel ratio operation under required operating conditions, a fuel injection valve that can directly inject fuel and pressurized air from a common injection port into the combustion chamber and an exhaust passage are arranged. An exhaust purification catalyst, a temperature rise determining means for determining a condition under which the temperature of the exhaust purification catalyst should be raised, and a fuel injection valve from the fuel injection valve during the expansion stroke or the exhaust stroke when the temperature of the exhaust purification catalyst needs to be raised. Exhaust gas purifying apparatus for a direct injection internal combustion engine, further comprising an additional fuel injection control means for injecting additional fuel and pressurized air. 2. Injecting fuel directly into the combustion chamber,
A fuel injection valve capable of directly injecting fuel and pressurized air from a common injection port into a combustion chamber in an exhaust gas purification device for a direct injection internal combustion engine that performs lean air-fuel ratio operation under required operating conditions; Main injection control means for injecting main fuel from an injection valve to perform stratified combustion; an exhaust purification catalyst disposed in an exhaust passage; and a temperature rise determination means for determining a condition for raising the temperature of the exhaust purification catalyst. And additional fuel injection control means for injecting additional fuel and pressurized air from a fuel injection valve during an expansion stroke or an exhaust stroke when conditions for raising the temperature of the exhaust purification catalyst are provided. Exhaust gas purification device for direct injection internal combustion engine. 3. The temperature rise determination means determines that a condition for raising the temperature of the exhaust gas purification catalyst is satisfied when the activity level of the exhaust gas purification catalyst has not reached a predetermined activity level. 3. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to 1 or 2. 4. The exhaust purification catalyst includes a catalyst that absorbs and releases NOx in the exhaust gas in accordance with the air-fuel ratio of the exhaust gas flowing into the exhaust gas purification device. 3. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to claim 1, wherein it is determined that a condition for raising the temperature of the exhaust gas purifying catalyst is satisfied when the SOx is to be released. 5. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to claim 1, wherein said additional fuel injection control means injects pressurized air from a fuel injection valve prior to injection of additional fuel. 6. The direct injection internal combustion engine according to claim 1, wherein said additional fuel injection control means injects additional fuel and pressurized air from a fuel injector, and further injects only pressurized air. Exhaust gas purification device. 7. The additional fuel injection control means starts the injection of pressurized air from the fuel injection valve prior to the injection of the additional fuel. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to claim 1 or 2, wherein the injection is terminated. 8. The additional fuel injection control means reduces an injection amount of pressurized air of a fuel injection valve according to a rise in a catalyst temperature and an engine operating temperature or an elapsed time from the start of control. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to any one of claims, 6, and 7. 9. The fuel injection control device according to claim 1, wherein the additional fuel injection control means delays the timing of starting injection of pressurized air from the fuel injection valve in accordance with an increase in catalyst temperature and engine operating temperature or an elapsed time from the start of control. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to any one of claims 2, 2, 6, and 7. 10. A main injection control means for injecting only main fuel from a fuel injection valve during a compression stroke or an intake stroke, and when the temperature of the exhaust purification catalyst is to be raised during injection of only the main fuel. 2. The exhaust gas purifying apparatus for a direct injection internal combustion engine according to claim 1, wherein said additional fuel injection control means injects only pressurized air from a fuel injection valve during an expansion stroke or an exhaust stroke.