JP2015121177A - Device for controlling internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling an internal combustion engine that uses a warming operation of a catalyst for regeneration operation of collection means (filter).SOLUTION: The device for controlling an internal combustion engine raises the temperature of the catalyst 20 by stratification slight lean combustion means when a predetermined condition including presence of a request for warming the catalyst 20 is satisfied, where if a particulate collected by the filter 18 is more than a predetermined amount, the device for controlling an internal combustion engine operates the stratification slight lean combustion means so as to perform the regeneration operation for the filter 18.

Description

  The present invention relates to a control device for an internal combustion engine that controls an exhaust purification device.

  A vehicle internal combustion engine is provided with a catalyst (for example, a three-way catalyst) that purifies harmful substances (HC, CO, NOx, etc.) in exhaust gas. In order to obtain exhaust gas purification performance, the catalyst needs to reach a predetermined activation temperature. For this reason, in a state where the catalyst temperature is low as in the cold start, the temperature of the catalyst is raised by additionally injecting fuel and raising the exhaust gas temperature.

  As a technology for raising the catalyst temperature at the cold start, the combustion state is controlled by changing the ignition timing (retarding) and changing the opening and closing timings of the exhaust valves and intake valves (changing the overlap amount). Conventionally, a technique for increasing the exhaust gas temperature by controlling the fuel ratio to a lean air-fuel ratio close to the stoichiometric air-fuel ratio and performing stratified combustion is known (for example, Patent Document 1).

  By the way, in recent years, there has been a demand for removal of particulate (PM) in exhaust gas in a spark ignition type internal combustion engine. For example, in a direct injection internal combustion engine that directly injects fuel into a combustion chamber, In order to remove fine particles in the exhaust gas discharged, a technique in which a filter for collecting fine particles (gasoline fine particle collecting filter) is provided in the exhaust passage has been studied.

  When the operation of the internal combustion engine continues for a predetermined period, the amount of fine particles deposited on the filter increases. For this reason, additional fuel is injected every predetermined period to raise the exhaust gas temperature to burn (remove) particulates deposited on the filter, and the filter is regenerated to maintain the collection performance.

  As described above, at the time of cold start, while the catalyst temperature raising operation is performed, the regeneration operation is performed to regenerate the filter when a predetermined amount of fine particles are collected, during the temperature raising operation, and During the regeneration operation, additional fuel is injected. For this reason, it is considered that a more efficient operation becomes possible by controlling the catalyst temperature raising operation and the filter regeneration operation.

Japanese Patent No. 4062884

  The present invention has been made in view of the above situation, and a control device for an internal combustion engine that can use a temperature raising operation for raising the temperature of a catalyst during a temperature raising operation of the catalyst for a filter regeneration operation. The purpose is to provide.

  To achieve the above object, a control device for an internal combustion engine of the present invention according to claim 1 is a control device for a spark ignition type internal combustion engine, provided in an exhaust passage of the internal combustion engine, and exhausted from the internal combustion engine. A predetermined condition including a catalyst for purifying exhaust gas, a collection means provided in the exhaust passage for collecting particulates in the exhaust gas discharged from the internal combustion engine, and a request for raising the temperature of the catalyst Is established, the fuel is injected in the compression stroke and the air-fuel ratio is controlled to a lean air-fuel ratio in the vicinity of the stoichiometric air-fuel ratio so that stratified combustion is performed, and the stratified light-lean combustion means is operated. Release control means, and when the predetermined condition is satisfied, the release control means operates the stratified light lean combustion means so as to raise the temperature of the catalyst, and captures the capture means. When the amount of the fine particles exceeds a predetermined amount, the overlap amount expanding operation for increasing the overlap amount at the opening / closing timing of the exhaust valve and the intake valve than when the fine particle is less than the predetermined amount, or the rising of the catalyst It is characterized in that at least one of the stratified light lean combustion continuing operation for continuing the operation of the stratified light lean combustion means after the temperature is completed is executed.

  In the present invention according to claim 1, when a predetermined condition including that there is a request for raising the temperature of the catalyst is satisfied, the temperature of the catalyst is raised by the stratified light lean combustion means, and the fine particles collected by the collecting means Is equal to or greater than a predetermined amount, at least one of the overlap amount expanding operation for expanding the overlap amount or the stratified light lean combustion continuing operation is performed compared to when the fine particles are less than the predetermined amount, and the collecting means The collected fine particles are removed from the collecting means. The overlap amount expanding operation and the stratified light lean combustion continuing operation are included in the operation of the stratified light lean combustion means.

  Therefore, the operation for raising the temperature of the catalyst during the operation for raising the temperature of the catalyst can be used for the regeneration operation of the filter.

  For this reason, it is possible to perform the combustion removal (removal) operation of fine particles while raising the temperature of the catalyst by stratified light lean combustion, and the frequency of the regeneration operation for forcibly removing the fine particles of the collecting means (filter). This can reduce fuel consumption and reduce fuel consumption.

  According to a second aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the first aspect of the present invention. In the control apparatus for the internal combustion engine according to the first aspect, when the release control means performs the overlap amount expanding operation, The overlap amount expanding operation is continued until the fine particles collected by the means become less than a predetermined amount.

  According to the second aspect of the present invention, the overlap amount expanding operation is continued until the particulate matter of the collecting means becomes less than a predetermined amount (for a predetermined period), that is, when the particulate matter becomes less than the predetermined amount, By terminating the lap amount expansion operation, it is possible to minimize deterioration in fuel consumption during temperature increase control of the catalyst.

  According to a third aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the first or second aspect, wherein the release control means causes the stratified light lean combustion continuation operation to be executed. In this case, the stratified light lean combustion continuation operation is continued until the fine particles collected by the collecting means become less than a predetermined amount.

  In the present invention according to claim 3, by continuing the stratified light lean combustion continuing operation until the particulates of the collecting means become less than a predetermined amount (for a predetermined period), that is, when the particulates become less than the predetermined amount, By terminating the light lean combustion continuation operation, it is possible to minimize the deterioration of fuel consumption during the temperature rise control of the catalyst.

  According to a fourth aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the first aspect of the present invention, wherein the release control means is configured to perform the overlap amount expanding operation even if the release control means performs the overlap amount expanding operation. When the particulate matter is collected in the collection means when the temperature rise is completed, the overlap amount expansion operation is terminated and the stratified light lean combustion continuation operation is executed. And

  In the present invention according to claim 4, if the particulate matter does not become less than the predetermined amount when the temperature rise of the catalyst is completed even if the overlap amount expansion operation is executed, only the stratified sludge lean combustion continuation operation is executed. Further, it is possible to minimize the deterioration of fuel consumption when performing the stratified light lean combustion while reducing the frequency of the regeneration operation for forcibly removing the particulates of the collection means (filter).

  An internal combustion engine control apparatus according to a fifth aspect of the present invention is the internal combustion engine control apparatus according to any one of the first to fourth aspects, wherein the differential pressure before and after the collecting means is detected. And the release control means recognizes that the amount of the fine particles collected by the collection means is a predetermined amount or more based on detection information of the differential pressure detection means. And

  In the present invention according to claim 5, it is possible to recognize that the amount of collected fine particles has increased by detecting that the differential pressure before and after the collecting means has increased by the differential pressure detecting means. it can. The amount of collected fine particles can also be recognized using a fine particle amount detection sensor that detects the weight of the fine particles.

  The exhaust gas purification apparatus for an internal combustion engine according to the present invention can utilize the catalyst temperature increasing operation for the regeneration operation of the collecting means (filter) during the operation of increasing the temperature of the catalyst.

It is a schematic block diagram of the internal combustion engine provided with the control apparatus which concerns on one Example of this invention. It is a control block diagram. It is explanatory drawing of the setting condition of valve overlap. It is a graph explaining the relationship between the amount of valve overlap, exhaust temperature, and HC emission amount. It is a control flowchart. It is a control flowchart.

  The control apparatus for an internal combustion engine according to the present embodiment controls the air-fuel ratio to a lean air-fuel ratio near the stoichiometric air-fuel ratio and performs stratified combustion when the temperature of the catalyst needs to be raised at the time of cold start or the like. The stratified light lean combustion operation is performed to raise the temperature and raise the temperature of the catalyst. When the amount of fine particles collected by the filter (gasoline fine particle collection filter) is more than the predetermined amount, the stratification is performed so that the fine particles collected by the filter are burned (removed) in addition to the temperature rise of the catalyst. Slight lean combustion is performed.

  Therefore, during the operation in which the temperature of the catalyst is raised, the catalyst temperature raising operation can be used for the filter regeneration operation. For this reason, it is possible to carry out particulate removal operation while raising the temperature of the catalyst by stratified light lean combustion, and to reduce fuel consumption by reducing the frequency of regeneration operation forcibly removing particulates from the filter. Can do.

  Here, the stratified light lean combustion in the present embodiment will be described.

  Stratified lean-lean combustion is a fuel spray, combustion chamber, piston top surface, and intake air flow configuration and control, and an in-cylinder air-fuel ratio so that a rich mixture is formed (stratified) in the vicinity of the spark plug. Is set to be weak (slight) lean (for example, about 14.8 to 17.0) to indicate a combustion mode in which stable ignition and combustion are obtained.

  A rich air-fuel mixture in the vicinity of the spark plug generates a high concentration of CO (for example, 0.5% or more) as compared with normal combustion that does not stratify after combustion. Further, since the air-fuel ratio in the cylinder is light lean, excess oxygen is present in the exhaust.

  Therefore, in stratified light lean combustion, high concentrations of CO and oxygen can be simultaneously supplied to the catalyst, and the oxidation reaction on the catalyst can be promoted to increase the temperature of the catalyst.

  Hereinafter, as a spark ignition type internal combustion engine, a cylinder injection type internal combustion engine in which fuel is directly injected into a combustion chamber (in-cylinder injection) will be described as an example. Although not shown in the figure, a supercharger for supercharging intake air is provided across the exhaust passage and the intake passage of the internal combustion engine. An internal combustion engine that combines port injection and in-cylinder injection can also be applied to the present invention.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration of an internal combustion engine provided with a control device according to an embodiment of the present invention, FIG. 2 is a configuration of a control block, FIG. 3 is a setting state of valve overlap, and FIG. The relationship between the lap amount, the exhaust temperature (a), and the HC emission amount (b), and FIG. 5 shows a control flowchart.

  A schematic configuration of a spark ignition type cylinder injection internal combustion engine (engine) will be described with reference to FIG.

  An intake port 3 is formed for each cylinder in the cylinder head 2 of the engine 1, and an intake valve 5 is provided on the combustion chamber 4 side of each intake port 3. The intake valve 5 is opened and closed following the cam of the camshaft that rotates in accordance with the engine rotation, and communicates and blocks the intake ports 3 and the combustion chambers 4. One end of an intake manifold 6 is connected to each intake port 3, and the intake manifold 6 communicates with each intake port 3.

  Further, the cylinder head 2 of the engine 1 is provided with an exhaust port 7 for each cylinder, and an exhaust valve 8 is provided on the combustion chamber 4 side of each exhaust port 7. The exhaust valve 8 is opened and closed following a cam of a camshaft that rotates in accordance with the engine rotation, and communicates and blocks the exhaust ports 7 and the combustion chamber 4. One end of an exhaust manifold 9 is connected to each exhaust port 7, and the exhaust manifold 9 communicates with each exhaust port 7.

  The intake valve 5 is provided with valve timing adjusting means 10 for changing the opening / closing timing of the intake valve 5. The valve timing adjustment means 10 is a mechanism that can adjust the opening / closing timing of the intake valve 5 by adjusting the phase of the intake camshaft, for example.

  A fuel injection valve 11 facing the combustion chamber 4 is attached to each cylinder of the cylinder head 2, and fuel is sent to the fuel injection valve 11 by driving a high-pressure fuel pump (not shown). A predetermined amount of fuel is injected from the fuel injection valve 11 into the combustion chamber 4 at a predetermined fuel pressure and at a predetermined fuel pressure. A spark plug 12 is provided at the top of the combustion chamber 4 of each cylinder of the cylinder head 2.

  An intake pipe 15 is connected to the intake manifold 6, and a throttle valve 16 for adjusting the intake air amount is provided in the intake pipe 15. The opening degree of the throttle valve 16 is detected by a throttle position sensor 21.

  An exhaust pipe 17 (exhaust passage) is connected to the exhaust manifold 9, and the exhaust pipe 17 is provided with a catalyst 20 (three-way catalyst, storage type NOx catalyst) for purifying harmful components in the exhaust, and upstream of the catalyst 20. The unit is provided with a high temperature sensor 31 for detecting the exhaust gas temperature and an air / fuel ratio sensor (not shown) for detecting the exhaust air / fuel ratio.

  On the downstream side of the catalyst 20, a filter (gasoline particulate collection filter) 18 is provided as a collection means for collecting particulates in the exhaust gas. An upstream pressure sensor 22 is provided in the exhaust pipe 17 upstream of the filter 18, and a downstream pressure sensor 23 is provided in the exhaust pipe 17 downstream of the filter 18. Based on the differential pressure detected by the upstream pressure sensor 22 and the downstream pressure sensor 23, the amount of fine particles collected by the filter 18 is estimated.

  The engine 1 is provided with a cooling water sensor 32 for detecting a cooling water temperature and a crank angle sensor 33 for detecting a crank angle (engine rotational speed Ne). Although not shown, an accelerator opening sensor, an air flow are shown. Sensors and the like are provided.

  The vehicle is provided with an electronic control unit (ECU) 25 that controls the engine 1. The ECU 25 receives the sensor detection information described above, and performs integrated control of the engine 1 based on the sensor information. That is, based on detection information from various sensors, the fuel injection timing, fuel injection pressure, fuel injection amount, etc. of the fuel injection valve 11 are controlled, and the ignition timing of the spark plug 12 is controlled.

  When the temperature of the catalyst 20 is required to be increased, that is, when the temperature of the storage-type NOx catalyst and the three-way catalyst is lowered, the air / fuel ratio (slight lean) is slightly leaner than the stoichiometric air / fuel ratio. In addition, the air-fuel ratio is controlled, and the ignition timing of the spark plug 12 and the change in the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 are integratedly controlled (stratified light lean combustion means).

Thereby, in addition to CO and HC, O ₂ is supplied to the catalyst 20 to promote the oxidation reaction, and the temperature rise of the catalyst 20 is promoted even in the cold state, thereby enabling early activation. .

  Although detailed description is omitted, the engine 1 is provided with a regeneration means for burning (removing) the particulates collected by the filter 18 in a predetermined operation cycle. For example, the engine 1 is operated in a state where the temperature of the filter 18 is raised by supplying additional fuel or the like, and the collected fine particles are removed.

  In this embodiment, the temperature of the catalyst 20 is raised by the stratified light lean combustion means when the temperature of the catalyst 20 is raised, such as during cold start. At this time, if it is estimated from the differential pressure detected by the upstream pressure sensor 22 and the downstream pressure sensor 23 that the amount of fine particles collected by the filter 18 is equal to or greater than a predetermined amount, the particulate matter collected by the filter 18 is collected. The stratified light lean combustion (the valve overlap amount expansion or the stratified lightly lean combustion continuing operation) is executed so that the fine particles removed are removed (release control means).

  Accordingly, the temperature increasing operation of the catalyst 20 can be used for the regeneration operation of the filter 18 during the stratified light lean combustion operation in which the temperature of the catalyst 20 is increased. For this reason, the temperature of the catalyst 20 can be raised by the stratified light lean combustion, and the particulate removal operation can be performed, and the frequency of the regeneration operation for forcibly removing the particulates of the filter 18 is reduced to suppress the deterioration of the fuel consumption. can do.

  The function of the ECU 25 will be specifically described with reference to FIGS.

  The ECU 25 includes a throttle position sensor 21, an upstream pressure sensor 22, a downstream pressure sensor 23, a high temperature sensor 31, a cooling water sensor 32, information on the crank angle sensor 33, air / fuel ratio information, and regeneration operation information of the filter 18 by the regeneration means. Is entered.

  The ECU 25 sets the fuel injection timing, the fuel injection pressure, and the fuel injection amount of the fuel injection valve 11 and the ignition timing of the spark plug 12 according to the driving state of the vehicle, and the set information is the fuel injection. It is output to the valve 11 and the spark plug 12 (driver).

  The ECU 25 is provided with a stratified light lean combustion means 35 and a release control means 36.

  The air-fuel ratio is controlled by the stratified light lean combustion means 35 so that the air-fuel ratio is slightly leaner than the stoichiometric air-fuel ratio (slight lean) when the temperature of the catalyst 20 is raised at the time of cold start or the like. The ignition timing of the plug 12 is adjusted, and the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 is changed early (valve overlap normal enlargement: stratified light lean combustion N during temperature rise).

  When it is estimated from the differential pressure detected by the upstream pressure sensor 22 and the downstream pressure sensor 23 that the amount of fine particles collected by the filter 18 is greater than or equal to a predetermined amount, the release control means 36 filters the filter 18. The stratified light lean combustion is performed so that the particulates collected in the catalyst are removed.

  That is, the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 is changed earlier (the overlap amount expanding operation) so that the valve overlap is expanded than the normal expansion of the valve overlap when the fine particles are less than the predetermined amount. : Regeneration time stratified light lean combustion S).

  Note that the release control means 36 can also continue the operation of the stratified slite lean combustion N during the temperature rise (stratified slite lean combustion continuation operation).

  As shown by a dotted line in FIG. 3, in the case of the valve overlap amount N when the valve overlap is normally expanded, the intake valve 5 starts to open at a time earlier by the arrow A than the normal valve opening timing. That is, as shown in FIGS. 4 (a) and 4 (b), the valve overlap amount N at the time of normal enlargement of the valve overlap is set so that the stratified light lean combustion N at the time of temperature rise is executed, and the HC emission The exhaust gas temperature is high to some extent while the amount is minimum.

  As shown by a thick line in FIG. 3, in the case of the valve overlap amount S (N <S) at the time of the overlap amount expansion operation, the intake valve is earlier at the timing indicated by the arrow B (A <B) than the normal valve opening timing. 5 begins to open. That is, as shown in FIGS. 4A and 4B, the regeneration stratified light lean combustion S is set to be executed with the valve overlap amount S at the time of the valve overlap amount expansion operation, and the HC emission The exhaust temperature is sufficiently high with the amount not so large.

  Based on FIG. 5, the control of the temperature rise of the catalyst 20 in the stratified light lean combustion means 35 and the release control means 36 and the control of removing the fine particles from the filter 18 will be specifically described.

  In step S1, the operation parameters are read, and in step S2, the accumulation amount Q of fine particles is estimated. That is, based on the detection information of the upstream pressure sensor 22 and the downstream pressure sensor 23, the differential pressure of the exhaust gas before and after the filter 18 is detected, and the accumulation amount Q of the fine particles is estimated. After the accumulation amount Q of the fine particles is estimated in step S2, it is determined whether or not a predetermined condition including a request for raising the temperature of the catalyst 20 is satisfied.

  That is, it is determined whether or not the engine is idling in step S3. If it is determined that the engine is idling in step S3, it is determined whether or not the engine is warming up in step S4. That is, it is determined whether or not the cooling water temperature (or exhaust temperature) is equal to or lower than a predetermined temperature. If it is determined in step S4 that the engine is warming up, it is determined in step S5 whether or not the accumulation amount Q is equal to or greater than a predetermined amount QB.

  If it is determined in step S3 that the engine is not idling, and if it is determined in step S4 that the engine is not warming up, the process ends and the process proceeds to normal operation control.

  If it is determined in step S5 that the accumulation amount Q is not equal to or greater than the predetermined amount QB, that is, it is determined that there is a request for raising the temperature of the catalyst 20 during warm-up during idle operation, and the particulates collected by the filter 18 Is less than the predetermined amount QB, the temperature-stratified stratified light lean combustion N is executed in step S6, and the process returns.

  That is, the air-fuel ratio is controlled so that the air-fuel ratio (slight lean) is slightly leaner than the stoichiometric air-fuel ratio, the ignition timing of the spark plug 12 is adjusted, and the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 Is quickly changed (state indicated by a dotted line in FIG. 3). Thereby, the temperature of the catalyst 20 is raised.

  When it is determined in step S5 that the accumulation amount Q is equal to or greater than the predetermined amount QB, that is, during the warm-up during the idle operation, there is a request for raising the temperature of the catalyst 20, and the filter 18 traps particulates exceeding the predetermined amount QB. When it is determined that they have been collected (when a predetermined condition including the request for raising the temperature of the catalyst 20 is satisfied), the regeneration stratified light lean combustion S is executed and a return is made.

  That is, the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 is larger than the normal expansion of the valve overlap when the particulates are less than the predetermined amount QB (the stratified light lean combustion N during the temperature rise). Is changed more quickly (indicated by a thick line in FIG. 3). As a result, the exhaust temperature can be further increased, the temperature of the catalyst 20 is raised, and the fine particles collected by the filter 18 are removed.

  By executing the regeneration-stratified slite lean combustion S, the temperature rising operation of the catalyst 20 can be used for the regeneration operation of the filter 18. A removal operation can also be performed. Thereby, the frequency of the regeneration operation for forcibly removing the fine particles of the filter 18 can be reduced, and deterioration of fuel consumption can be suppressed.

  Based on FIG. 6, another embodiment of the control of the temperature rise of the catalyst 20 in the stratified light lean combustion means 35 and the release control means 36 and the control for removing the fine particles from the filter 18 will be specifically described.

  In step S11, the operation parameters are read, and in step S12, the accumulation amount Q of fine particles is estimated. That is, based on the detection information of the upstream pressure sensor 22 and the downstream pressure sensor 23, the differential pressure of the exhaust gas before and after the filter 18 is detected, and the accumulation amount Q of the fine particles is estimated.

  After the accumulation amount Q of the fine particles is estimated in step S12, it is determined in step S13 whether or not the idling operation is being performed. If it is determined in step S13 that the engine is idling, it is determined in step S14 whether the engine is warming up. That is, it is determined whether or not the cooling water temperature (or exhaust temperature) is equal to or lower than a predetermined temperature. If it is determined in step S14 that the engine is warming up, it is determined in step S15 whether the accumulation amount Q is equal to or greater than a predetermined amount QB. If it is determined in step S13 that the idling operation is not being performed, the process ends, and the control shifts to the normal operation control.

  If it is determined in step S15 that the accumulation amount Q is not equal to or greater than the predetermined amount QB, that is, it is determined that there is a request for raising the temperature of the catalyst 20 during warm-up during idle operation, and the particulates collected by the filter 18 Is less than the predetermined amount QB, the temperature-stratified slight lean combustion N is executed in step S16, and the process returns.

  That is, the air-fuel ratio is controlled so that the air-fuel ratio (slight lean) is slightly leaner than the stoichiometric air-fuel ratio, the ignition timing of the spark plug 12 is adjusted, and the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 Is quickly changed (state indicated by a dotted line in FIG. 3). Thereby, the temperature of the catalyst 20 is raised.

  When it is determined in step S15 that the accumulation amount Q is equal to or greater than the predetermined amount QB, that is, during the warm-up during the idle operation, there is a request for increasing the temperature of the catalyst 20, and the filter 18 traps particulates exceeding the predetermined amount QB. When it is determined that the catalyst has been collected (when a predetermined condition including a request for raising the temperature of the catalyst 20 is satisfied), the release flag Fgpf is set to 1 in step S17, and the regeneration stratified light lean combustion S is executed in step S18. And return.

  That is, the opening / closing timing of the intake valve 5 by the valve timing adjusting means 10 is larger than the normal expansion of the valve overlap when the particulates are less than the predetermined amount QB (the stratified light lean combustion N during the temperature rise). Is changed more quickly (indicated by a thick line in FIG. 3). As a result, the exhaust temperature can be further increased, the temperature of the catalyst 20 is raised, and the fine particles collected by the filter 18 are removed.

  On the other hand, if it is determined in step S14 that the engine is not warming up, that is, if the idling operation is being performed but it is determined that the temperature increase of the catalyst 20 has been completed, the release flag Fgpf is 1 in step S21. It is determined whether or not there is.

  If it is determined in step S21 that the release flag Fgpf is 1, since it is considered that fine particles of a predetermined amount QB or more are collected in the filter 18, the release flag Fgpf release condition is satisfied in step S22. It is judged whether or not. If it is determined in step S21 that the release flag Fgpf is not 1, that is, the release flag Fgpf is 0, the process ends, and the process proceeds to normal operation control.

  The release condition of the release flag Fgpf is set when the particulates collected by the filter 18 become less than a predetermined amount QB, or when a predetermined time has elapsed after the regeneration stratified light lean combustion S is executed. Yes.

  If it is determined in step S22 that the release flag Fgpf release condition is satisfied, the release flag Fgpf is set to 0 in step S23, the process ends, and control is shifted to normal operation.

  When it is determined in step S22 that the release flag Fgpf release condition is not satisfied, the release flag Fgpf is released on the assumption that the release flag Fgpf is 1 (on the assumption that the overlap amount expansion operation is executed). It is determined that the condition is not satisfied.

  That is, even when the overlap amount expanding operation is executed, when the temperature of the catalyst 20 is increased (when it is determined that the catalyst 20 is not warmed up in step S14), the filter 18 traps the particulates by a predetermined amount QB or more. It is judged that it is gathered.

  If it is determined in step S22 that the release condition for the release flag Fgpf is not satisfied, the temperature-rise stratified light lean combustion N is executed in step S16, and the process returns. That is, the stratified light lean combustion continuing operation is executed without executing the regeneration stratified light lean combustion S which is the overlap amount expanding operation.

  If it is determined in step S22 that the release condition for the release flag Fgpf is not satisfied, it is possible to execute regeneration-time stratified light lean combustion S in step S18.

  If the particulate matter collected by the filter 18 does not become less than the predetermined amount QB when the temperature of the catalyst 20 is completed even if the overlap amount expanding operation is executed, the stratified light lean combustion continuous operation (temperature increase) Since only the stratified slight lean combustion N) is executed, it is possible to minimize the deterioration of fuel consumption when the stratified slight lean lean combustion is performed while reducing the frequency of the regeneration operation for forcibly removing the fine particles of the filter 18. it can.

  The above-described exhaust gas purification apparatus for an internal combustion engine can use the stratified light lean lean combustion for the regeneration operation of the filter 18 during the operation of performing the stratified light lean combustion where the temperature of the catalyst 20 is increased.

  The present invention can be used in the industrial field of a control device for an internal combustion engine equipped with an exhaust purification device.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 3 Intake port 4 Combustion chamber 5 Intake valve 6 Intake manifold 7 Exhaust port 8 Exhaust valve 9 Exhaust manifold 10 Valve timing adjustment means 11 Fuel injection valve 12 Spark plug 15 Intake pipe 16 Throttle valve 17 Exhaust pipe 18 Filter 20 Catalyst 21 Throttle position sensor 22 Upstream pressure sensor 23 Downstream pressure sensor 25 Electronic control unit (ECU)
31 High temperature sensor 32 Cooling water sensor 35 Stratified light lean combustion means 36 Release control means

Claims (5)

A spark ignition internal combustion engine control device,
A catalyst that is provided in an exhaust passage of the internal combustion engine and purifies exhaust gas discharged from the internal combustion engine;
A collecting means provided in the exhaust passage for collecting particulates in the exhaust discharged from the internal combustion engine;
A stratified slightly fuel that performs stratified combustion by injecting fuel in a compression stroke and controlling the air-fuel ratio to a lean air-fuel ratio in the vicinity of the theoretical air-fuel ratio when a predetermined condition including that there is a temperature increase request of the catalyst is established Combustion means,
Release control means for operating the stratified light lean combustion means,
The release control means includes
When the predetermined condition is satisfied, the stratified light lean combustion means is operated so as to raise the temperature of the catalyst,
When the fine particles collected by the collecting means are a predetermined amount or more,
The overlap amount expanding operation for increasing the overlap amount at the opening / closing timing of the exhaust valve and the intake valve than when the fine particles are less than the predetermined amount, or even after the temperature rise of the catalyst is completed, A control device for an internal combustion engine, wherein at least one of a stratified light lean combustion continuing operation for continuing the operation is executed. The control apparatus for an internal combustion engine according to claim 1,
The release control means includes
When the overlap amount expanding operation is executed, the overlap amount expanding operation is continued until the fine particles collected by the collecting means become less than a predetermined amount. The control apparatus for an internal combustion engine according to claim 1 or 2,
The release control means includes
The control of the internal combustion engine characterized in that, when the stratified light lean combustion continuing operation is executed, the stratified light lean combustion continuing operation is continued until the fine particles collected by the collecting means become less than a predetermined amount. apparatus. The control apparatus for an internal combustion engine according to claim 1,
The release control means includes
Even if the overlap amount expansion operation is executed, the overlap amount expansion operation is terminated when the particulate matter has been collected in the collection means when the temperature of the catalyst is increased. And a control device for an internal combustion engine, wherein the stratified light lean combustion continuing operation is executed. The control device for an internal combustion engine according to any one of claims 1 to 4,
A differential pressure detecting means for detecting a differential pressure before and after the collecting means;
The release control means includes
A control apparatus for an internal combustion engine, characterized in that it recognizes that the amount of the fine particles collected by the collection means has become a predetermined amount or more based on detection information of the differential pressure detection means.

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