JP6210215B2 - Control device for internal combustion engine - Google Patents

Description

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

  In recent years, spark ignition type internal combustion engines have been required to remove particulates (PM) in exhaust gas. For example, in a direct injection internal combustion engine that directly injects fuel into a combustion chamber, the internal combustion engine is discharged from the internal combustion engine. In order to remove particulates in the exhaust gas, a technique of providing a filter for collecting PM (gasoline particulate collection filter) in the exhaust passage has been studied. In this technique, when the operation of the internal combustion engine continues for a predetermined period, the amount of fine particles collected by the filter increases. For this reason, the particulates are burned (removed) by raising the temperature of the filter or the like every predetermined period, and the filter is regenerated to maintain the collection performance.

  In general, filters used in spark ignition internal combustion engines have a higher porosity than filters used in diesel engines (diesel particulate collection filters) to minimize exhaust pressure loss. It is. For this reason, immediately after regenerating the filter, the exhaust gas passes through the pore wall having a high porosity, which increases the number of fine particles that pass through the fine pores of the filter and may reduce the collection performance of the fine particles. there were.

  In order to maintain the collection performance of fine particles, when the amount of collected fine particles is small, for example, the temperature of the exhaust gas passing through the filter is increased to increase the thermal momentum of the exhaust gas particles, and the particles on the pore walls of the filter A technique for collecting fine particles by collision is known (see, for example, Patent Document 1). With the technique of Patent Document 1, the collection performance can be maintained by promoting the collection of fine particles.

  However, since the technique of Patent Document 1 is a technique of a diesel engine and is applied to a filter having a low porosity, the particulate collection performance can be maintained. When applied to a filter with a high porosity used in a spark ignition type internal combustion engine, even when the amount of collected fine particles is small, the fine particles do not have pores until the exhaust temperature rises. Immediately after the filter is regenerated, the fine particles are discharged, and it is difficult to suppress the discharge of the fine particles.

  In the diesel engine, when a filter with a high porosity is used, the same problem may occur.

JP 2011-208542 A

  The present invention has been made in view of the above situation, and provides a control device for an internal combustion engine that can suppress discharge of fine particles even when fine particles are not collected by a collecting means (filter). With the goal.

In order to achieve the above object, a control device for an internal combustion engine according to claim 1 of the present invention is a control device for an internal combustion engine, wherein an exhaust passage of the internal combustion engine includes an exhaust gas exhausted from the internal combustion engine. A collecting means for collecting fine particles is provided, and a regenerating means for removing the fine particles collected by the collecting means, and a period after the fine particles are removed from the collecting means by the regenerating means. with a duration monitor which, and control means the period of time that is grasped by the period grasping means reaches the first predetermined time period, performing a fine suppression control to suppress the generation of particles from the internal combustion engine, the control The means is characterized in that the degree of suppression of the generation of the fine particles is reduced as the period grasped by the period grasping means approaches the first predetermined period .

In the first aspect of the present invention, a predetermined amount of fine particles are collected by the collecting means until the period after the fine particles are removed from the collecting means (after regeneration) reaches the first predetermined period. The fine particle suppression control for suppressing the generation of fine particles is executed until the number of fine particles passing through the collecting means is equal to or less than a predetermined allowable value. Therefore, the fine particles in the exhaust gas are collected until a predetermined amount of fine particles are collected by the collecting means. The number of fine particles passing through the collecting means decreases without increasing the number of particles.
As the period after the fine particles are removed from the collecting means approaches the first predetermined period (the longer the period), that is, as the amount of fine particles collected by the collecting means increases, the generation of fine particles Since the degree of suppression is reduced, the particulate suppression control can be minimized. For this reason, it is possible to suppress a decrease in output and fuel consumption of the internal combustion engine caused by the particulate suppression control.

  Therefore, it is possible to suppress the discharge of the fine particles even when the fine particles are not collected by the collecting means (filter) after the regeneration after the fine particles are removed from the collecting means.

  When the fine particle suppression control is configured by a plurality of means, for example, the plurality of fine particle suppression control means can be gradually reduced one by one. Further, when the fine particle suppression control is configured by one fine particle suppression control means, the degree of suppression of the single fine particle suppression control means can be gradually reduced.

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 , wherein the particulate suppression control is a control for enriching the air-fuel ratio of the fuel of the internal combustion engine. A first control, a second control for retarding the fuel injection timing of the internal combustion engine, a third control for controlling the fuel injection pressure of the internal combustion engine, and an ignition timing of the internal combustion engine. It is control which restrict | limits at least any one among 4th control which is control to advance.

In the present invention according to claim 2 , if the control that facilitates the discharge of particulates is restricted, the adhesion of fuel to the combustion chamber wall surface, piston top surface, and cylinder liner is suppressed, and fuel atomization is promoted. The discharge of fine particles can be suppressed.

According to a third aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the second aspect , wherein the control means is configured such that the period grasped by the period grasping means is the first period. The first control restriction is executed until the predetermined period is reached.

In the present invention according to claim 3 , until the first predetermined period is reached, that is, until a predetermined amount of fine particles are collected by the collecting means, the number of discharged fine particles in the first to fourth controls. The first control for enriching the air-fuel ratio, which is the control that has the greatest influence on the air-fuel ratio, is limited. That is, an increase in the amount of particulate components discharged from the internal combustion engine can be suppressed until the first predetermined period is reached, and the number of particulates passing through the collecting means can be more reliably reduced.

According to a fourth aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the third aspect , wherein the control means is configured such that the period grasped by the period grasping means is the first period. The second control restriction is executed until a second predetermined period shorter than the predetermined period is reached.

In the present invention according to claim 4 , the number of discharged particulates in the first to fourth controls until the second predetermined period, that is, until the latter half of the stage when the particulates are collected by the collecting means. The second control for retarding the injection timing, which is the second largest control that affects the engine, is limited. That is, until the second predetermined period, in addition to the enrichment of the air-fuel ratio, the retarding of the injection timing is also restricted, so that the discharge of particulates from the internal combustion engine can be suppressed more reliably. Moreover, since the restriction on retarding the injection timing is released after the second predetermined period has elapsed, it is possible to reduce the decrease in the output of the internal combustion engine and the deterioration in fuel consumption.

According to a fifth aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the fourth aspect , wherein the control means is configured such that the period grasped by the period grasping means is the second period. The third control restriction is executed until a third predetermined period shorter than the predetermined period is reached.

In the present invention according to claim 5 , the number of discharged particulates in the first to fourth controls until the third predetermined period, that is, until the first half stage when the particulates are collected by the collecting means. The control that lowers the fuel injection pressure, which is the third largest control that affects the engine, is limited. That is, since the first to third controls are limited until the third predetermined period, it is possible to more reliably suppress the discharge of particulates from the internal combustion engine. Further, since the restriction on the decrease in the fuel injection pressure is released after the third predetermined period has elapsed, the decrease in the output of the internal combustion engine and the deterioration in fuel consumption can be reduced.

According to a sixth aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the fifth aspect , wherein the control means is configured such that the period grasped by the period grasping means is the third period. Until the fourth predetermined period shorter than the predetermined period is reached, the restriction of the fourth control is executed.

In the present invention according to claim 6 , since the fourth control for advancing the ignition timing is limited until the fourth predetermined period, that is, until the initial stage in which the particulates are deposited, A mixing period is ensured. That is, since the first to fourth controls are limited until the fourth predetermined period, it is possible to more reliably suppress the discharge of particulates from the internal combustion engine. Further, since the restriction on the advance angle of the ignition timing is released after the fourth predetermined period has elapsed, it is possible to reduce the output of the internal combustion engine and the deterioration of fuel consumption.

According to a seventh aspect of the present invention, there is provided a control device for an internal combustion engine according to any one of the first to sixth aspects, wherein the collecting means captures the predetermined period. It is a period until the amount of the collected fine particles reaches a predetermined value, and the period grasping means grasps the period based on the amount of the fine particles collected by the collecting means. It is characterized by.

In the present invention according to claim 7 , the predetermined period is grasped based on the amount of the fine particles collected by the collecting means. That is, the predetermined period is grasped by detecting an increase in the amount of fine particles. The amount of fine particles can be detected by a fine particle detection sensor. It is also possible to detect that the amount of fine particles has increased due to an increase in the differential pressure before and after the filter.

  The control device for an internal combustion engine of the present invention can suppress the discharge of fine particles even when the fine particles are not collected by the collecting means (filter).

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 a flowchart. It is a graph explaining the characteristic of the number of discharged fine particles. It is a graph explaining the relationship between the number of discharged fine particles and the air-fuel ratio. It is a graph explaining the relationship between the number of discharged fine particles and fuel injection end timing. It is a graph explaining the relationship between the number of discharged particulates and fuel pressure. It is a graph explaining the relationship between the number of discharged fine particles and the ignition timing. It is a graph explaining the time-dependent change of the fine particle deposition amount of a filter.

  The control apparatus for an internal combustion engine according to the present embodiment regenerates the filter for collecting particulates (gasoline particulate collection filter) and then collects a predetermined amount of particulates on the filter until the first predetermined period elapses. Until then, the operation to suppress the generation of fine particles (fine particle suppression control: control to limit (prohibit) the operation in which the amount of generated fine particles is increased) is executed. For this reason, generation | occurrence | production of microparticles | fine-particles is suppressed and the number of microparticles | fine-particles which pass a filter reduces.

  In the embodiment described below, a means for restricting (prohibiting) an operation in which the amount of generated fine particles increases is applied as the fine particle suppression control means.

  For this reason, in the exhaust gas purification apparatus using a filter having a high porosity, it is possible to suppress discharge of fine particles even in a state where fine particles are not collected by the filter after regeneration. Therefore, the exhaust gas performance can be improved with a filter having a high porosity in a state where fine particles are not collected.

  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.

  It should be noted that the present invention can also be applied as an exhaust purification device for an internal combustion engine that combines port injection and in-cylinder injection. Moreover, it is also possible to apply the diesel engine provided with the filter (diesel particulate collection filter) which set the porosity high as this invention.

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

  FIG. 1 shows a schematic configuration of an internal combustion engine provided with a control device according to an embodiment of the present invention, FIG. 2 shows a configuration of a control block, and FIG. 3 shows a control flowchart.

  FIG. 4 shows the characteristics of the number of discharged fine particles, FIG. 5 shows the relationship between the number of discharged fine particles and the air-fuel ratio, and FIG. 6 shows the relationship between the number of discharged fine particles and the fuel injection end time. FIG. 7 shows the relationship between the number of discharged fine particles and fuel pressure, FIG. 8 shows the relationship between the number of discharged fine particles and ignition timing, and FIG. 9 shows the change over time in the amount of accumulated fine particles on the filter. .

  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.

  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 three-way catalyst (not shown) for purifying harmful components in the exhaust, and on the downstream side of the three-way catalyst, A filter (gasoline particulate collection filter) 18 is provided as a collecting means for collecting particulates in the exhaust.

  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.

  Although not shown, the engine 1 includes a sensor that detects an air-fuel ratio, a cooling water sensor that detects a cooling water temperature, a crank angle sensor that detects a crank angle (engine rotational speed Ne), an accelerator opening sensor, an air flow sensor, and the like. Is 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.

  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, and the collected fine particles are removed (regeneration).

  The above-described filter 18 of the engine 1 has a higher porosity than a filter (diesel particulate collection filter) used in a diesel engine in order to suppress exhaust pressure loss to a minimum. Since the porosity is high, immediately after the filter 18 is regenerated, the exhaust passes through the pore walls with a high porosity, increasing the number of fine particles that pass through the fine pores of the filter and improving the collection performance of the fine particles. There was a risk of lowering.

  That is, as shown in FIG. 4 showing the characteristics of the number of fine particles passing through the filter 18 after regeneration, when a predetermined period has elapsed since regeneration (shown by a dotted line), before the predetermined period has elapsed after regeneration. It is confirmed that the number of fine particles is increased (indicated by a solid line).

  Immediately after the filter 18 is regenerated, the collection performance of the fine particles may be reduced. Therefore, after the filter 18 is regenerated, until the predetermined period (first predetermined period) elapses, that is, the fine particles are applied to the filter 18. Until a predetermined amount is collected, the operation in which the amount of generated fine particles is increased is restricted (prohibited). For this reason, the ECU 25 as the control means is provided with a function of performing particulate suppression control that restricts the operation in which the amount of generated particulates increases.

  The function of the ECU 25 will be specifically described based on FIG.

  The ECU 25 receives information such as information detected by the throttle position sensor 21, upstream pressure sensor 22, and downstream pressure sensor 23, air-fuel ratio, engine rotational speed Ne, and cooling water temperature. Further, the regeneration operation information of the filter 18 by the regeneration means is input.

  The ECU 25 includes an air-fuel ratio control function 31, an injection timing control function 32, an injection pressure control function 33, and an ignition timing control function 34, and the fuel injection timing, fuel injection pressure, and fuel injection amount of the fuel injection valve 11 are set. In addition, the ignition timing of the spark plug 12 is set, and the set information is output to the fuel injection valve 11 and the spark plug 12 (driver).

  The ECU 25 is provided with a limiting function 41 as a function for limiting (prohibiting) an operation in which the amount of generated fine particles increases. The information set by the limiting function 41 is sent to the air-fuel ratio control function 31, the injection timing control function 32, the injection pressure control function 33, and the ignition timing control function 34, so that the operation signal is prevented so as not to increase the amount of generated particulates. Is output.

  The restriction function 41 is provided with period grasping means 42 for grasping the period after the fine particles are removed from the filter 18 by the regeneration means. The period grasping means 42 detects the differential pressure of the exhaust before and after the filter 18 based on the detection information of the upstream pressure sensor 22 and the downstream pressure sensor 23, and when the differential pressure of the exhaust becomes large (the back pressure is high). It is determined that the amount of collected fine particles has increased.

  When it is determined that the amount of collected fine particles has increased, the period grasping means 42 recognizes that the period from regeneration by the regeneration means has reached a predetermined period. For example, the period is grasped in four stages based on the collection amount in four stages (a first predetermined period, a second predetermined period, a third predetermined period, and a fourth predetermined period).

  When the predetermined period is grasped by the period grasping means 42, an operation that increases the generation amount of fine particles is selected in accordance with the four predetermined periods, and each function is executed from the execution means 43 so that the restriction (prohibition) is executed. An operation command is sent to.

In this example, the operation in which the amount of generated fine particles is increased,
(1) Driving the air-fuel ratio to the rich side (control to enrich the air-fuel ratio: first control)
(2) Operation for retarding fuel injection timing (control for retarding fuel injection timing: second control)
(3) Operation for reducing fuel injection pressure (control for reducing fuel injection pressure: third control)
(4) Driving to advance ignition timing (control to advance ignition timing: fourth control)
Applies.

  The influence on the number of discharged fine particles is large in the first control (1), and the second control (2), the third control (3), and the fourth control (4) are in descending order. And the generation | occurrence | production of microparticles | fine-particles is suppressed by restrict | limiting (prohibiting) the driving | operation of 1st control (1) to 4th control (4).

  As shown in FIG. 5, it has been confirmed that the number of fine particles increases rapidly by making the air-fuel ratio rich from stoichiometric. For this reason, the first control (1), which is an operation to bring the air-fuel ratio to the rich side, is applied as the operation in which the amount of generated fine particles increases.

  As shown in FIG. 6, it has been confirmed that by delaying the fuel injection timing, the premixing period of fuel and air is shortened and the number of fine particles is increased. For this reason, the second control (2), which is an operation for retarding the fuel injection timing, is applied as an operation in which the amount of generated fine particles increases.

  As shown in FIG. 7, it has been confirmed that by reducing the fuel pressure, the number of fine particles increases without promoting atomization of the fuel. For this reason, the third control (3), which is an operation for reducing the fuel injection pressure, is applied as an operation for increasing the amount of generated fine particles.

  As shown in FIG. 8, it has been confirmed that the advancement of the ignition timing shortens the premixing period and increases the number of fine particles. For this reason, the fourth control (4), which is an operation for advancing the ignition timing, is applied as an operation in which the amount of generated fine particles increases.

  Then, as shown in FIG. 9 showing the change over time in the amount of collected fine particles, until the time t1 after the filter 18 is regenerated by the regenerating means (fourth predetermined amount: until the fourth predetermined period), First, the operation for making the air-fuel ratio rich, which is the first control (1), the operation for retarding the fuel injection timing, which is the second control (2), and the fuel injection pressure, which is the third control (3) All the operations that lower the ignition timing and the fourth control (4) that advance the ignition timing are prohibited (restricted).

  Thereafter, until the third predetermined period, which is the third predetermined amount at time t2, the operation for making the air-fuel ratio rich, which is the first control (1), and the fuel injection timing, which is the second control (2) The operation for retarding the angle and the operation for reducing the fuel injection pressure, which is the third control (3), are prohibited (restricted).

  Further, until the second predetermined period, which is the second predetermined amount at time t3, the operation for making the air-fuel ratio rich, which is the first control (1), and the fuel injection timing, which is the second control (2) Driving to retard the angle is prohibited (restricted).

  Furthermore, until the first predetermined period, which is the first predetermined amount at time t4, is reached, the operation for making the air-fuel ratio rich, which is the first control (1), is prohibited (restricted).

The relationship of the predetermined period is
First predetermined period> second predetermined period> third predetermined period> fourth predetermined period.

  That is, as the first predetermined period is approached (the longer the predetermined period is), the types of operation in which the amount of generated fine particles is increased are decreased one by one. That is, the degree of control of the generation of fine particles is reduced. For this reason, it is possible to minimize the execution of the particulate suppression control, and it is possible to suppress a decrease in output of the engine 1 and a decrease in fuel consumption.

  When the operation in which the amount of generated fine particles is increased is constituted by one means, the degree of control of the generation of fine particles can be reduced by gradually reducing the degree of suppression of one means. For example, when only the operation that makes the air-fuel ratio rich, which is the first control (1), is applied, the degree of control of the generation of fine particles is reduced by gradually controlling the rich degree of the air-fuel ratio to the stoichiometric side. be able to.

  Based on FIG. 3, the control operation for restricting (prohibiting) the operation in which the amount of generated fine particles is increased will be specifically described.

  In step S1, it is determined whether or not the regeneration is completed. If it is determined in step S1 that the regeneration is completed, the throttle opening Th that is the opening of the throttle valve 16 is greater than the predetermined opening ThA in step S2. It is determined whether or not it is small. That is, it is determined whether or not there is no output request.

  If it is determined in step S1 that the regeneration has not ended, and if it is determined in step S2 that the throttle opening Th is equal to or greater than the predetermined opening ThA (there is an output request), a return is returned.

  When it is determined in step S2 that the throttle opening Th is smaller than the predetermined opening ThA, the amount Q of collected particulates is estimated in step S3. 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 trapped amount Q of the fine particles is estimated.

  If it is determined in step S4 whether the collected amount Q is smaller than the fourth predetermined amount Q4, and if it is determined in step S4 that the collected amount Q is smaller than the fourth predetermined amount Q4, FIG. It is determined that the time is between time t1 (fourth predetermined period). For this reason, in step S5, the first control (1) is the operation to make the air-fuel ratio rich, the first control (2) is the operation to retard the fuel injection timing, and the third control ( 3) The operation for lowering the fuel injection pressure and the fourth control (4) the operation for advancing the ignition timing are all prohibited (restricted) and returned.

  Therefore, during the initial stage where particulates are collected while particulate control is being performed, control to make the air-fuel ratio rich, control to retard fuel injection timing, control to lower fuel injection pressure, ignition Since the control for advancing the timing is limited, the amount of the particulate component of the fuel is not increased, the fuel premixing period is sufficiently secured, and the particulate emission can be reliably suppressed.

  When it is determined in step S4 that the collected amount Q is equal to or greater than the fourth predetermined amount Q4, it is determined in step S6 whether the collected amount Q is smaller than the third predetermined amount Q3. When it is determined in step S6 that the collected amount Q is smaller than the third predetermined amount Q3, it is determined that the time is between time t2 in FIG. 9 (third predetermined period). For this reason, in step S7, the first control (1) is performed to make the air-fuel ratio rich, the second control (2) is the operation to retard the fuel injection timing, and the third control (3). The operation for reducing the fuel injection pressure is prohibited (restricted) and returns.

  Therefore, during the first half of the stage when particulate control is performed, control to make the air-fuel ratio rich, control to retard the fuel injection timing, and control to lower the fuel injection pressure are limited. Therefore, the amount of the fine particle component of the fuel does not increase, a state in which the fuel is easily premixed is ensured, and the discharge of the fine particles can be suppressed. Moreover, deterioration of fuel consumption can be suppressed.

  If it is determined in step S6 that the collected amount Q is greater than or equal to the third predetermined amount Q3, it is determined in step S8 whether or not the collected amount Q is smaller than the second predetermined amount Q2. When it is determined in step S8 that the collected amount Q is smaller than the second predetermined amount Q2, it is determined that the time is until time t3 in FIG. 9 (second predetermined period). Therefore, in step S9, the operation that makes the air-fuel ratio rich, which is the first control (1), and the operation that retards the fuel injection timing, which is the second control (2), are prohibited (restricted) and returned. It becomes.

  Therefore, during the latter half of the stage when particulate control is performed, the control to make the air-fuel ratio rich and the retarding of the injection timing are limited, so the amount of particulate component in the fuel is reduced. There is no increase, a fuel premixing period is ensured, and particulate discharge can be suppressed. Moreover, deterioration of output and fuel consumption can be suppressed.

  When it is determined in step S8 that the collected amount Q is equal to or greater than the second predetermined amount Q2, it is determined in step S10 whether the collected amount Q is less than the predetermined amount Q1. If it is determined in step S10 that the collected amount Q is smaller than the predetermined amount Q1, it is determined that the time is between time t4 in FIG. 9 (first predetermined period). For this reason, in step S11, the operation for making the air-fuel ratio rich, which is the first control (1), is prohibited (restricted) and returns.

  Accordingly, since the control for enriching the air-fuel ratio is limited until the first predetermined period is reached, the amount of the particulate component of the fuel does not increase, and the particulate discharge can be suppressed.

  If it is determined in step S10 that the collected amount Q is equal to or greater than the predetermined amount Q1, it is determined that the fine particles are collected to some extent and the pores of the filter 18 are small, and the possibility that the fine particles pass through is low. Therefore, the control for limiting (prohibiting) the operation in which the amount of generated fine particles increases is terminated.

  The control apparatus for an internal combustion engine described above is configured so that, even after the regeneration operation of the filter 18 that removes (releases) the collected fine particles, the fine particles are not collected by the filter 18 having a high porosity. Since the number of fine particles in one exhaust does not increase, the number of discharged fine particles can be suppressed.

  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 11 Fuel injection valve 12 Spark plug 15 Intake pipe 16 Throttle valve 17 Exhaust pipe 18 Filter 21 Throttle position sensor 22 Upstream Pressure sensor 23 Downstream pressure sensor 25 Electronic control unit (ECU)
31 Air-fuel ratio control function 32 Injection timing control function 33 Injection pressure control function 34 Ignition timing control function 41 Limit function 42 Period grasping means 43 Executing means

Claims (7)

A control device for an internal combustion engine,
The exhaust passage of the internal combustion engine is provided with a collecting means for collecting fine particles in the exhaust discharged from the internal combustion engine,
Regenerating means for removing the fine particles collected by the collecting means;
Period grasping means for grasping a period after the fine particles are removed from the collecting means by the regeneration means;
Control means for executing fine particle suppression control for suppressing generation of fine particles from the internal combustion engine until the period grasped by the period grasping means reaches a first predetermined period ;
The control means includes
The control apparatus for an internal combustion engine, wherein the degree of suppression of the generation of the fine particles is reduced as the period grasped by the period grasping means approaches the first predetermined period . The control apparatus for an internal combustion engine according to claim 1 ,
The fine particle suppression control is
1st control which is control which enriches the air fuel ratio of the fuel of the said internal combustion engine, 2nd control which is control which retards the fuel injection timing of the said internal combustion engine, control which reduces the fuel injection pressure of the said internal combustion engine A control device for an internal combustion engine, wherein at least one of the third control and the fourth control, which is a control for advancing the ignition timing of the internal combustion engine, is limited. The control apparatus for an internal combustion engine according to claim 2 ,
The control means includes
The control apparatus for an internal combustion engine, wherein the restriction of the first control is executed until the period grasped by the period grasping means reaches the first predetermined period. The control apparatus for an internal combustion engine according to claim 3 ,
The control means includes
The internal combustion engine is characterized in that the second control restriction is executed until the period grasped by the period grasping means reaches a second predetermined period shorter than the first predetermined period. Control device. The control apparatus for an internal combustion engine according to claim 4 ,
The control means includes
The restriction of the third control is executed until the period grasped by the period grasping means reaches a third predetermined period shorter than the second predetermined period. Control device. The control apparatus for an internal combustion engine according to claim 5 ,
The control means includes
The limitation of the fourth control is executed until the period grasped by the period grasping means reaches a fourth predetermined period shorter than the third predetermined period. Control device. The control apparatus for an internal combustion engine according to any one of claims 1 to 6 ,
The predetermined period is
A period until the amount of the fine particles collected by the collecting means reaches a predetermined value,
The period grasping means is:
The control apparatus for an internal combustion engine, wherein the period is grasped based on an amount of the fine particles collected by the collecting means.

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