JP2022036181A - Exhaust gas purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly regenerate a collection filter collecting particulate matters.

SOLUTION: An exhaust emission control device is equipped with a GPF (17) collecting soot discharged from an engine (2), and an ECU (3) executing the temperature rise control of the GPF. The EUC has a forcible regeneration determining portion (30) determining the forcible regeneration of the GPF, and a temperature rise control portion (31) changing temperature rise control on the basis of engine rotation speed and an engine load when the forcible regeneration determining portion determines the forcible regeneration of GPF. The temperature rise control portion executes temperature rise control for a low area in a low area where the engine rotation speed and/or the engine load is low, and executes temperature rise control for a high area in a high area where the engine rotation speed and/or the engine load is high. The temperature rise control includes at least control for adjusting an ignition timing.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an exhaust gas purification device.

In some vehicle engines, fine particles (particulate) such as carbon contained in the exhaust gas are collected by a trap (see, for example, Patent Document 1). In such an engine, the accumulation of particulates may cause the exhaust pressure to rise excessively and reduce engine performance. In order to prevent this, a device is provided to regenerate the trap by burning the deposited particulate at a predetermined time.

In Patent Document 1, the amount of collected and reburned particulates is determined based on the engine load and the number of revolutions, and the trap regeneration time is determined according to the results.

Japanese Patent No. 2623879

However, if the temperature rise control is performed without considering the driving state of the engine, the trap may not be properly regenerated because the trap regeneration temperature may not be reached or the trap may be overheated. is assumed.

The present invention has been made in view of the above points, and an object of the present invention is to provide an exhaust gas purification device capable of appropriately regenerating a collection filter that collects particulate matter.

The exhaust gas purification device of one aspect of the present invention includes a collection filter that collects soot discharged from the engine and a control device that controls the temperature rise of the collection filter, and the control device is the collection device. When the forced regeneration determination unit that determines the forced regeneration of the collection filter and the forced regeneration determination unit determine the forced regeneration of the collection filter, the temperature rise control is changed based on the engine speed and the engine load. It has a control unit, and the temperature rise control unit performs temperature rise control for a low region in a low region where the engine speed and / or the engine load is low, and the engine speed and / or the engine load is high. In the high region, the temperature rise control for the high region is carried out, and the temperature rise control includes at least a control for adjusting the ignition timing.

According to the present invention, a collection filter that collects particulate matter can be appropriately regenerated.

It is an overall block diagram of the engine control system which concerns on this embodiment. It is a figure which shows the control map based on the engine speed and the engine load. It is a figure which shows an example of the GPF reproduction control flow which concerns on this embodiment. It is a time chart which shows the time-dependent change of various parameters which concerns on this embodiment. It is a time chart which shows the time-dependent change of various parameters which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The engine control system according to the present embodiment will be described with reference to FIG. FIG. 1 is an overall configuration diagram of an engine control system according to the present embodiment. The engine control system is not limited to the configuration shown below, and can be changed as appropriate.

As shown in FIG. 1, the engine control system 1 according to the present embodiment is configured to control the operation of the engine 2 as an internal combustion engine and its peripheral configuration by an ECU 3 (Electronic Control Unit). Although details will be described later, the ECU 3 constitutes a control device that is a part of the exhaust gas purification device of the present application. The engine 2 is composed of, for example, a direct acting multi-cylinder DOHC (Double OverHead Camshaft) engine. The engine 2 accommodates a crankshaft 20 in a crankcase (not shown), and includes a cylinder 21, a cylinder head 22, and the like.

A piston 23 is housed in the cylinder 21 so as to be reciprocating in a predetermined direction (up and down in FIG. 1). The crankshaft 20 and the piston 23 are connected by a connecting rod 24. In the engine 2, the crankshaft 20 is rotated via the connecting rod 24 by reciprocating the piston 23 in a predetermined direction.

The internal space of the cylinder head 22 constitutes the combustion chamber 25. A spark plug 26 as an ignition device is provided in the upper part of the combustion chamber 25. The spark plug 26 ignites at a predetermined timing based on the ignition signal output from the ECU 3, and ignites the air-fuel mixture in the combustion chamber 25.

The cylinder head 22 is formed with an intake port 27a and an exhaust port 27b communicating with the combustion chamber 25. Further, the cylinder head 22 is provided with an intake valve 28a and an exhaust valve 28b corresponding to the intake port 27a and the exhaust port 27b. An intake camshaft 29a and an exhaust camshaft 29b are provided at the upper ends of the intake valve 28a and the exhaust valve 28b.

A camchain (not shown) is bridged over the crankshaft 20, the intake camshaft 29a, and the exhaust camshaft 29b. The rotation of the crankshaft 20 is transmitted to the intake camshaft 29a and the exhaust camshaft 29b via the cam chain. By rotating the intake camshaft 29a and the exhaust camshaft 29b, the intake valve 28a and the exhaust valve 28b are reciprocated toward the combustion chamber 25 at predetermined timings.

An intake pipe 10 is connected to the upstream end of the intake port 27a via an intake manifold (not shown). The passage in the intake pipe 10 and the intake port 27a form an intake passage for the intake air. An air cleaner 11, a throttle valve 12, and a surge tank 13 are provided in the middle of the intake pipe 10 from the upstream side. An air amount sensor 40 is provided in the intake pipe 10 between the air cleaner 11 and the throttle valve 12. The air amount sensor 40 detects the amount of intake air (mass flow rate) that passes through the air cleaner 11 and flows in the intake pipe 10, and outputs the detected value to the ECU 3.

The throttle valve 12 includes, for example, a butterfly valve, and is opened and closed in response to a command from the ECU 3 to adjust the flow rate (intake air amount) of the intake air flowing in the intake pipe 10. The surge tank 13 has a sufficiently large volume as compared with the intake pipe 10 and prevents the pulsation of the intake air. The surge tank 13 is provided with an intake pressure sensor 41. The intake pressure sensor 41 detects the pressure (intake pressure) of the intake air in the surge tank 13, and outputs the detected value to the ECU 3. The ECU 3 can estimate the engine load from the above-mentioned intake air amount and intake pressure.

The intake pipe 10 (or intake port 27a) on the downstream side of the surge tank 13 is provided with an injector 14 as a fuel injection device for injecting fuel. The injector 14 injects a predetermined amount of fuel into the intake pipe 10 (or the intake port 27a) in response to a command from the ECU 3. That is, the engine 2 according to the present embodiment is composed of a so-called port injection type engine.

An exhaust pipe 15 is connected to the downstream end of the exhaust port 27b via an exhaust manifold (not shown). The passages in the exhaust port 27b and the exhaust pipe 15 form an exhaust gas passage. A catalyst 16 for purifying exhaust gas is provided in the middle of the exhaust pipe 15 as a part of the exhaust gas purification device. The catalyst 16 is composed of, for example, a three-way catalyst, and converts pollutants (carbon dioxide, hydrocarbons, nitrogen oxides, etc.) in the exhaust gas into harmless substances (carbon dioxide, water, nitrogen, etc.). When the engine 2 is a diesel engine, for example, an oxidation catalyst is used for the catalyst 16.

The exhaust pipe 15 on the downstream side of the catalyst 16 is provided with a GPF 17 (Gasoline Particulate Filter) as a collecting filter for collecting particulate matter (PM: Particulate Matter) such as soot generated by combustion of the engine 2. .. Temperature sensors 18a and 18b are provided before and after (upstream and downstream) the GPF 17. The temperature sensors 18a and 18b detect the exhaust gas temperature before and after the GPF 17, and output the detected value to the ECU 3.

Further, the GPF 17 is provided with a differential pressure sensor 19. The differential pressure sensor 19 detects the pressure difference before and after the GPF 17, and outputs the detected value to the ECU 3. The ECU 3 can estimate the clogging state of the GPF 17, that is, the amount of PM collected from the pressure difference.

The exhaust gas purification device according to the present embodiment includes the above-mentioned engine 2 and its peripheral configurations (catalyst 16, GPF 17, ECU 3, various sensors, etc.).

In the engine 2 configured as described above, the intake air that has passed through the air cleaner 11 flows into the intake port 27a through the surge tank 13 after the flow rate is adjusted by the throttle valve 12. At this time, fuel is injected from the injector 14 at a predetermined timing, and the intake air and the fuel are mixed in the intake port 27a. The air-fuel mixture of the intake air and the fuel flows into the combustion chamber 25 at the timing when the intake valve 28a is opened, is compressed in the combustion chamber 25, and then is ignited by the spark plug 26 at a predetermined timing. The exhaust gas after being ignited and burned is discharged to the outside from the exhaust port 27b through the exhaust pipe 15. At this time, the exhaust gas is purified by the catalyst 16, PM is collected by the GPF 17, and then the exhaust noise is reduced by a muffler (not shown).

Further, the engine 2 is provided with a water temperature sensor 42 for detecting the engine water temperature and a crank sensor 43 for detecting the phase of the crankshaft 20. Each detection value of the water temperature sensor 42 and the crank sensor 43 is output to the ECU 3. It is possible to calculate the engine speed from the output of the crank sensor 43.

Further, the vehicle is provided with a vehicle speed sensor 44 for detecting the vehicle speed, a brake pedal 45, and an accelerator pedal 46. The detection value of the vehicle speed sensor 44 is output to the ECU 3. The brake pedal 45 constitutes a braking means for generating a braking force on the vehicle, and outputs a predetermined electric signal according to the depression amount (treading force) to the ECU 3. The accelerator pedal 46 constitutes an accelerating means for generating an accelerating force in the vehicle, and outputs a predetermined electric signal corresponding to the depression amount (depression force) to the ECU 3.

The ECU 3 controls the operation of the entire vehicle including various configurations inside and outside the engine 2. The ECU 3 is composed of a processor, a memory, and the like that execute various processes. The memory is composed of a storage medium such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the intended use. A control program or the like that controls the various configurations described above is stored in the memory.

The ECU 3 determines the state of the vehicle from various sensors provided in the vehicle and controls the drive of various configurations around the engine. For example, the ECU 3 determines whether to forcibly regenerate the GPF 17 based on the PM accumulated amount (collected amount) in the GPF 17, and drives the injector 14, the spark plug 26, and the throttle valve 12 based on the operating condition of the engine 2. Then, a predetermined temperature rise control for the GPF 17 is performed.

Although the details will be described later, the ECU 3 stores in advance a control map (see FIG. 2) defined based on the engine speed and the engine load in order to carry out the predetermined temperature rise control. The ECU 3 can raise the temperature of the GPF 17 by controlling fuel injection, ignition, and the like based on the control map.

For example, the ECU 3 has a plurality of functional blocks depending on the configuration to be controlled. Specifically, the ECU 3 has a forced regeneration determination unit 30 that determines forced regeneration of the GPF 17, and a temperature rise control unit 31 that performs predetermined temperature rise control according to the determination result of the forced regeneration determination unit 30. There is.

Note that these functional blocks are merely examples for convenience, and the ECU 3 is not limited to these functional blocks and may have other functional blocks. Further, even if these functional blocks are not provided, the ECU 3 may comprehensively perform the following various controls.

The forced regeneration determination unit 30 determines whether or not to perform forced regeneration of the GPF 17 based on the amount of PM accumulated in the GPF 17. The amount of PM accumulated in the GPF 17 can be estimated from, for example, the detection value of the differential pressure sensor 19. That is, the forced regeneration determination unit 30 determines the presence / absence (necessity) of forced regeneration of the GPF 17 based on the detection value of the differential pressure sensor 19. Specifically, the forced regeneration determination unit 30 determines that forced regeneration of the GPF 17 is necessary when the PM storage amount is equal to or greater than a predetermined amount, and when the PM storage amount is less than the predetermined amount, the forced regeneration of the GPF 17 is unnecessary. Is determined to be.

The forced regeneration determination unit 30 may determine whether or not forced regeneration is necessary based on the temperature of the GPF 17. For example, the forced regeneration determination unit 30 determines that forced regeneration of the GPF 17 is necessary when the temperature of the GPF 17 does not reach the predetermined temperature, and when the temperature of the GPF 17 is equal to or higher than the predetermined temperature, the forced regeneration of the GPF 17 is unnecessary. May be determined. Further, the temperature of the GPF 17 is not limited to the detected values of the temperature sensors 18a and 18b, and may be estimated from the operating state of the engine 2 such as the fuel injection amount.

The temperature rise control unit 31 controls the drive of various configurations in the engine 2 in order to carry out control for raising the temperature of the GPF 17 (hereinafter referred to as temperature temperature control). For example, the temperature rise control unit 31 controls the ignition timing of the spark plug 26, the fuel injection amount and injection timing of the injector 14, and the opening degree of the throttle valve 12.

The temperature rise control unit 31 can execute a plurality of temperature rise controls, and when the forced regeneration determination unit 30 determines the forced regeneration of the GPF 17, it is determined based on the control map defined by the engine speed and the engine load. The temperature rise control is carried out.

Here, a plurality of temperature rise controls will be described. As described above, the temperature rise control is a control for raising the temperature of the GPF 17, and any control method may be adopted as long as the temperature of the GPF 17 can be raised. For example, the following control method can be considered.

(1) First, there is a temperature rise control by an ignition retard angle that delays the ignition timing of the spark plug 26. When the ignition is retarded, the time at which combustion ends is delayed, so the temperature in the exhaust stroke increases. As a result, it is possible to raise the temperature of GPF 17.
(2) Next, there is a temperature rise control by leaning the air-fuel ratio. As a method of leaning the air-fuel ratio, it is conceivable to increase the opening degree of the throttle valve 12 to increase the intake air amount. By increasing oxygen (intake air amount) in a state where the exhaust temperature has risen, the PM collected in the GPF 17 can be burned to raise the temperature.
(3) Next, there is a temperature rise control by thinning out (pausing) the fuel injection of the injector 14. By thinning out the fuel injection, only the warm air after combustion can be sent to the exhaust side, and the temperature of the GPF 17 can be raised.
(4) Next, the temperature rise control by thinning out (pausing) the ignition of the spark plug 26 and continuing the fuel injection can be mentioned. By thinning out the ignition, the air-fuel mixture (fuel) that does not burn in the combustion chamber can be sent to the exhaust side, and the fuel is burned by the catalyst 16 on the downstream side of the exhaust to indirectly raise the temperature of the GPF 17. Is possible.
In addition to these, a method of directly providing a heater (not shown) on the GPF 17 to control the drive of the heater can be mentioned.

The temperature rise control unit 31 appropriately selects one or a plurality of temperature rise controls from the plurality of temperature rise controls described above, and implements the temperature rise control alone or in combination. Further, although the details will be described later, the temperature rise control unit 31 selects or changes some temperature rise controls from the plurality of temperature rise controls based on the above-mentioned control map.

In the present embodiment, the temperature rise control unit 31 controls so that the temperature of the GPF 17 is maintained at a predetermined temperature for controlling the regeneration of the GPF 17. The control is performed by increasing or decreasing the number of the temperature rise control described above or changing the value of the temperature rise control itself. The timing for changing the control may be a case where the temperature deviates from the predetermined temperature by a certain value, a case where the slope of the temperature change is large, or the like.

By the way, in the conventional exhaust gas purification device, there is an apparatus that monitors the PM accumulation amount in the collection filter, determines the regeneration time of the collection filter according to the PM accumulation amount, and implements the temperature rise control. However, if the temperature rise control is performed only by the amount of PM accumulated without considering the driving state of the engine, the temperature of the collecting filter may not reach the regeneration temperature or the collecting filter may overheat depending on the driving state of the engine. It is assumed that the collection filter cannot be properly regenerated.

Therefore, the inventor of the present invention has conceived to appropriately regenerate the GPF 17 in consideration of the driving state (operating condition) of the engine. In the present embodiment, when the GPF 17 requires forced regeneration, the ECU 3 changes the temperature rise control based on the engine speed and the engine load. Specifically, when the forced regeneration determination unit 30 determines the regeneration of the GPF 17, the temperature rise control unit 31 refers to a preset control map, and which region on the control map the current operating condition of the engine 2 belongs to. Select or change the predetermined temperature rise control based on. That is, after the temperature rise control is started based on a predetermined condition, the content of the temperature rise control is changed according to the state of the engine 2. As a result, the temperature rise control is carried out according to the operating condition of the engine 2, and the forced regeneration of the GPF 17 can be appropriately performed.

Next, the control map according to the present embodiment will be described with reference to FIG. FIG. 2 is a diagram showing a control map based on the engine speed and the engine load. In FIG. 2, the horizontal axis represents the engine speed and the vertical axis represents the engine load. The engine speed and engine load usually increase as the vehicle speed increases due to the depression of the accelerator pedal. On the contrary, the engine speed and the engine load decrease as the vehicle speed decreases due to deceleration. The engine load may be other parameters such as the amount and pressure of intake air and filling efficiency.

As described above, the ECU 3 stores in advance a control map defined based on the engine speed and the engine load in order to carry out the filter regeneration promotion control. As shown in FIG. 2, the control map is divided into a plurality of regions according to the engine speed and the engine load. In FIG. 2, the horizontal axis is divided into 5 and the vertical axis is divided into 6, and the area is divided into a total of 30 areas. Each area is numbered. It should be noted that this number does not indicate any particular order, but is given for convenience in order to specify each area. Further, the number of regions is not limited to this, and can be appropriately changed according to the accuracy of temperature rise control.

Further, these regions are classified into three types according to the engine speed and the high and low engine load (PM accumulation level of GPF17). Specifically, it is classified into three types of regions, the first region, the second region, and the third region, in order from the region where the engine speed and / or the engine load is small (in descending order of PM deposition level). In FIG. 2, the areas are shown by hatching in which the areas are different for each classification. In the present embodiment, the first region where the engine speed and / or the engine load is relatively low is referred to as a low region, and the second region and the third region where the engine speed and / or the engine load is relatively high are combined. We will call it the high region.

The first region represents a region where the exhaust temperature is relatively low and the engine 2 is operating in a relatively low load state, and is a region where PM is likely to be accumulated in the GPF 17. That is, it can be said that the first region is a region where the PM deposition level is large and the active regeneration of GPF 17 should be promoted (the region where the temperature of GPF 17 should be raised). As the operating condition of the engine 2 belonging to the first region, for example, the case where the vehicle is stopped at a traffic light or the state of idling can be considered.

The second region is a region between the first region and the third region, and is a region that does not require active regeneration of the GPF 17 as much as the first region. That is, it can be said that the second region is a region where the PM deposition level is medium. As the operating condition of the engine 2 belonging to the second region, for example, a case where the vehicle is constantly traveling at a relatively small speed can be considered.

The third region, in which the engine speed and / or the engine load is larger than that in the first region and the second region, is a region in which the exhaust temperature is sufficiently high and can be naturally regenerated without promoting the active regeneration of the GPF 17. Is. That is, it can be said that the third region has the smallest PM deposition level among the three regions and does not require active regeneration of GPF17. As the operating condition of the engine 2 belonging to the third region, for example, the case where the vehicle is suddenly accelerating or the vehicle is traveling at high speed can be considered.

As described above, in the present embodiment, when the ECU 3 determines that the forced regeneration of the GPF 17 is necessary, the control map is referred to, and which region on the control map the current operating condition of the engine 2 belongs to. Based on this, a predetermined temperature rise control is selected or changed. For example, the temperature rise control unit 31 performs temperature rise control for a low region in a low region (first region) and temperature temperature control for a high region in a high region (second region or third region). implement.

Specifically, the temperature rise control unit 31 increases the number of temperature rise controls as the operating condition of the engine 2 is in the lower region. As an example of the temperature rise control for a low region, it is conceivable to carry out all of the above-mentioned plurality of temperature rise controls in combination. Since active forced regeneration of the GPF 17 is required in the low region, it is possible to appropriately raise the temperature of the GPF 17 to promote regeneration by increasing the temperature rise control.

On the other hand, the temperature rise control unit 31 reduces the number of temperature rise controls as the operating condition of the engine 2 is in the higher region. As an example of the temperature rise control in the high region, among the plurality of temperature rise controls described above, a number of temperature rise controls smaller than the number of temperature rise controls adopted in the low region is selected or combined. In the high region, the lower the region, the more the active forced regeneration of the GPF 17 is unnecessary. Therefore, by reducing the temperature rise control than in the low region, it is possible to prevent the GPF 17 from overheating and appropriately reproduce the GPF 17. be.

Further, as will be described in detail later, when the operating condition of the engine 2 transitions from the high region to the low region during the temperature rise control for the high region, the temperature rise control unit 31 changes the temperature of the GPF 17 to the region after the transition. The temperature rise control for the high region is maintained until the temperature drops to the predetermined temperature specified in 1. This is because the temperature of the GPF 17 does not decrease when the transition from the high region to the low region occurs, and if the temperature rise control for the low region is immediately changed, the temperature of the GPF 17 may be excessively increased. This makes it possible to prevent the GPF 17 from overheating.

Further, when the operating condition of the engine changes from the low region to the high region during the temperature rise control for the low region, the temperature rise control unit 31 immediately changes to the temperature rise control for the high region. This is because the number of temperature rise controls is reduced when the transition is made from the low region to the high region, so that the excessive temperature rise of the GPF 17 does not become a problem.

Further, it is preferable that the temperature rise control unit 31 increases the number of temperature rise controls as the time required for the temperature of the GPF 17 to decrease to a predetermined temperature determined for each region is shorter. When the temperature of the GPF 17 decreases at a high speed, the temperature of the GPF 17 can be raised at an early stage by increasing the number of temperature raising controls, and the GPF 17 can be suitably regenerated. Further, it is preferable that the temperature determined for each region is set to a higher temperature as the region is lower.

Next, the control flow according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram showing an example of the GPF regeneration control flow according to the present embodiment. In the control flow shown below, unless otherwise specified, the main body of the operation (calculation (calculation), judgment, etc.) is the ECU.

As shown in FIG. 4, when the GPF regeneration control is started, in step ST101, the ECU 3 determines whether or not forced regeneration of the GPF 17 is necessary. If forced reproduction of GPF 17 is required (step ST101: YES), the process proceeds to step ST102. When the forced regeneration of GPF 17 is unnecessary (step ST101: NO), the process of step ST101 is repeated.

In step ST102, the ECU 3 determines whether or not the operating condition of the engine 2 belongs to the high region. When the operating condition of the engine 2 belongs to the high region, that is, when the operating condition of the engine 2 belongs to the second region or the third region (step ST102: YES), the process proceeds to the process of step ST103. When the operating condition of the engine 2 does not belong to the high region, that is, when the operating condition of the engine 2 belongs to the first region which is the low region (step ST102: NO), the process proceeds to step ST108.

In step ST103, the ECU 3 reduces the number of temperature rise controls. This makes it possible to prevent overheating while maintaining the temperature of the GPF 17 at a temperature suitable for regeneration. Then, the process proceeds to step ST104.

In step ST104, the ECU 3 determines whether or not the forced regeneration of the GPF 17 has been completed. For example, the ECU 3 can determine the end of forced regeneration of the GPF 17 based on the temperature of the GPF 17, the amount of PM accumulated, the temperature rise time, and the like. When the forced reproduction of the GPF 17 ends (step ST104: YES), the control ends. If the forced reproduction of GPF 17 is not completed (step ST104: NO), the process proceeds to step ST105.

In step ST105, the ECU 3 determines whether or not the operating condition of the engine 2 has changed from the high region to the low region. When the operating condition of the engine 2 changes from the high region to the low region (step ST105: YES), the process proceeds to step ST106. When the operating condition of the engine 2 does not change from the high region to the low region (step ST105: NO), the process returns to the process of step ST103.

In step ST106, the ECU 3 determines whether or not the temperature of the GPF 17 is equal to or lower than the predetermined temperature. When the temperature of GPF 17 is equal to or lower than the predetermined temperature (step ST106: YES), the process proceeds to step ST107. When the temperature of GPF 17 is higher than the predetermined temperature (step ST106: NO), the process of step ST106 is repeated. That is, the process of step ST106 is repeated until the temperature of GPF 17 becomes equal to or lower than the predetermined temperature.

In step ST107, the ECU 3 determines and executes the number of temperature rise controls according to the time until the temperature of the GPF 17 drops to a predetermined temperature. Then, the process proceeds to step ST109.

In step ST108, the ECU 3 increases the number of temperature rise controls. As a result, the temperature of GPF 17 is positively raised, and regeneration is promoted. Then, the process proceeds to step ST109.

In step ST109, the ECU 3 determines whether or not the forced regeneration of the GPF 17 has been completed. When the forced reproduction of the GPF 17 ends (step ST109: YES), the control ends. If the forced reproduction of GPF 17 is not completed (step ST109: NO), the process proceeds to step ST110.

In step ST110, the ECU 3 determines whether or not the operating condition of the engine 2 has changed from the low region to the high region. When the operating condition of the engine 2 transitions from the low region to the high region (step ST110: YES), the process returns to the process of step ST103, and the number of temperature rise controls is immediately reduced (for high region temperature rise control). change). When the operating condition of the engine 2 does not change from the low region to the high region (step ST110: NO), the process returns to the process of step ST108.

In this way, by changing the temperature rise control based on the control map while performing the predetermined temperature rise control, the temperature of the GPF 17 can be controlled to a temperature suitable for regeneration, and the regeneration of the GPF 17 is appropriately promoted. It is possible.

Next, with reference to FIGS. 4 and 5, changes over time of various parameters when the control (GPF regeneration control) according to the present embodiment is applied will be described. 4 and 5 are time charts showing changes over time of various parameters during the implementation of temperature rise control, and the vertical axis shows the GPF temperature, the number of temperature rise controls, and the region to which the temperature rise control belongs, in order from the top. FIG. 4 shows an example in which the operating condition of the engine transitions from a high region to a low region, and FIG. 5 shows an example in which the operating condition of the engine transitions from a low region to a high region.

As shown in FIG. 4, the temperature of the GPF 17 is maintained in a state higher than a predetermined predetermined temperature while the temperature rise control for a high region where the number of temperature rise controls is small is being carried out. Then, even if the operating condition of the engine 2 changes from the high region to the low region at the timing of T1, the ECU 3 does not immediately change the temperature rise control at the timing of T1. The ECU 3 maintains the temperature rise control for the high region until the temperature of the GPF 17 reaches a predetermined temperature. Then, when the temperature of the GPF 17 becomes equal to or lower than the predetermined temperature at the timing of T2, the ECU 3 increases the number of temperature rise controls and changes to the temperature rise control for the low region. As a result, the temperature rise of GPF 17 is promoted, and the temperature of GPF 17 gradually rises after T2. It is preferable that the ECU 3 increases the number of temperature rise controls in the temperature rise control for the low region after T2 as the time required for the temperature decrease of the GPF 17 between T1 and T2 is short. In this case, even if the temperature of the GPF 17 decreases, the temperature of the GPF 17 can be raised to a predetermined temperature at an early stage.

As shown in FIG. 5, the temperature of the GPF 17 is gradually increasing during the temperature rise control for a low region where the number of temperature rise controls is large. Then, when the operating condition of the engine 2 changes from the low region to the high region at the timing of T3, the ECU 3 immediately reduces the number of temperature rise controls and changes to the temperature rise control for the high region. As a result, the temperature increase rate of GPF 17 decreases, and the temperature of GPF 17 is maintained at a constant temperature while gradually increasing. In this way, it is possible to control the temperature of the GPF 17.

As described above, in the present embodiment, when forced regeneration is required for the GPF 17, the temperature of the GPF 17 is controlled to a temperature suitable for regeneration by changing the temperature rise control based on the engine speed and the engine load. It is possible to appropriately regenerate the GPF 17 according to the operating condition of the engine 2.

In the above embodiment, the port injection type engine 2 has been described as an example, but the present invention is not limited to this configuration. For example, the direct injection type engine 2 may be used.

Further, in the above embodiment, the description has been made by taking a gasoline engine as an example, but the present invention is not limited to this. This control can be applied even to a diesel engine.

Further, in the above embodiment, the DOHC engine has been described as an example, but the present invention is not limited thereto. The engine 2 may be a SOHC (Single OverHead Camshaft) engine.

Further, in the above embodiment, the case where the control map is classified into three regions has been described, but the present invention is not limited to this. The control map may be divided into two regions or four or more regions.

Further, in the above embodiment, a case where the number of temperature rise controls is changed when switching (changing) between the temperature rise control for the low region and the temperature rise control for the high region has been described, but the present invention is limited to this. Not done. For example, a predetermined parameter may be changed for one temperature rise control. For example, when the ignition is thinned out, the frequency of thinning out may be increased in the low region and the frequency of thinning out may be decreased in the high region.

Moreover, although the present embodiment and the modified example have been described, as another embodiment of the present invention, the above-described embodiment and the modified example may be combined in whole or in part.

Further, the embodiment of the present invention is not limited to the above-described embodiment, and may be variously modified, replaced, or modified without departing from the spirit of the technical idea of the present invention. Further, if the technical idea of the present invention can be realized in another way by the advancement of the technology or another technology derived from it, it may be carried out by the method. Therefore, the scope of claims covers all embodiments that may be included within the scope of the technical idea of the present invention.

As described above, the present invention has an effect that a collection filter that collects particulate matter can be appropriately regenerated, and is particularly useful for an exhaust gas purification device for a vehicle engine.

1: Engine control system 2: Engine 3: ECU (control device)
10: Intake pipe 11: Air cleaner 12: Throttle valve 13: Surge tank 14: Injector (fuel injection device)
15: Exhaust pipe 16: Catalyst 17: GPF (collection filter)
18a: Temperature sensor 18b: Temperature sensor 19: Differential pressure sensor 20: Crankshaft 21: Cylinder 22: Cylinder head 23: Piston 24: Connecting rod 25: Combustion chamber 26: Spark plug (ignition device)
27a: Intake port 27b: Exhaust port 28a: Intake valve 28b: Exhaust valve 29a: Intake camshaft 29b: Exhaust camshaft 30: Forced regeneration determination unit 31: Temperature rise control unit 40: Air volume sensor 41: Intake pressure sensor 42: Water temperature sensor 43: Crank sensor 44: Vehicle speed sensor 45: Brake pedal 46: Accelerator pedal

Claims (5)

A collection filter that collects soot discharged from the engine,
A control device for controlling the temperature rise of the collection filter is provided.
The control device is
The forced regeneration determination unit that determines the forced regeneration of the collection filter, and the forced regeneration determination unit.
It has a temperature rise control unit that changes the temperature rise control based on the engine speed and the engine load when the forced regeneration determination unit determines the forced regeneration of the collection filter.
The temperature rise control unit performs temperature rise control for a low region in a low region where the engine speed and / or the engine load is low, and for a high region in a high region where the engine speed and / or the engine load is high. Implemented temperature rise control,
The exhaust gas purification device, wherein the temperature rise control includes at least a control for adjusting an ignition timing. When the operating condition of the engine changes from the high region to the low region during the temperature rise control for the high region, the temperature rise control unit determines the temperature of the collection filter in the region after the transition. The exhaust gas purification device according to claim 1, wherein the temperature rise control for a high region is maintained until the temperature drops to a predetermined temperature. The temperature rise control unit immediately changes to the temperature rise control for the high region when the operating condition of the engine changes from the low region to the high region while the temperature rise control for the low region is being performed. The exhaust gas purification device according to claim 1 or 2, characterized in that. The temperature rise control unit can carry out a plurality of temperature rise controls, and the number of temperature rise controls is increased as the operating condition of the engine is in the lower region, according to claims 1 to 3. Exhaust purification device according to any one. The temperature rise control unit can perform a plurality of temperature rise controls, and the shorter the time required for the temperature of the collection filter to drop to a predetermined temperature determined for each region, the more the number of temperature rise controls. The exhaust gas purification device according to claim 2, wherein the number is increased.

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