WO2015145996A1

WO2015145996A1 - Control device for internal combustion engine

Info

Publication number: WO2015145996A1
Application number: PCT/JP2015/001119
Authority: WO
Inventors: 真吾中田
Original assignee: 株式会社デンソー
Priority date: 2014-03-25
Filing date: 2015-03-03
Publication date: 2015-10-01
Also published as: JP2015183607A

Abstract

When an execution condition for catalyst early warm-up control is met after an engine (11) is started, catalyst early warm-up control is executed wherein the ignition timing is controlled so as to be shifted toward the retard side and the air-fuel ratio is controlled so as to be on the lean side. Particulate matter captured by a gasoline particulate filter (GPF) (25) is burned due to an increase in the exhaust gas temperature and an increase of oxygen in the exhaust gas caused by the catalyst early warm-up control. Whether or not a predetermined amount or more of particulate matter captured by the filter has been burned is determined by determining whether or not the pressure difference between the front and back of the GPF (25) is equal to or smaller than a predetermined value. The catalyst early warm-up control continues until it is determined that the predetermined amount or more of the particulate matter captured by the filter has been burned. Consequently, the GPF (25) is reliably regenerated without resulting in poorer emission during the catalyst early warm-up control.

Description

Control device for internal combustion engine

Cross-reference of related applications

This disclosure is based on Japanese Patent Application No. 2014-61541 filed on March 25, 2014, the contents of which are incorporated herein.

The present disclosure relates to a control device for an internal combustion engine including a PM filter that collects particulate matter discharged from the internal combustion engine.

¡Particulate substances discharged from in-cylinder injection gasoline engines as well as diesel engines are being regulated. Not only the PM emission weight but also the number of particulate emissions are regulated. In response to such stricter regulations, it is considered that a gasoline engine is equipped with a PM filter that collects particulate matter discharged from the engine, as in the case of a diesel engine.

In a system equipped with such a PM filter, if the amount of particulate matter deposited on the PM filter (the amount of particulate matter deposited on the PM filter) becomes too large, the PM filter becomes clogged and the exhaust pressure is increased. Loss may become too large, leading to engine output reduction and fuel consumption deterioration. Further, if the particulate matter burns in a high temperature environment with an excessive amount of particulate matter deposited on the PM filter, excessive heat is generated, which may cause melting of the PM filter. For this reason, it is necessary to periodically perform regeneration control for burning and removing particulate matter deposited on the PM filter to regenerate the PM filter (to reduce the particulate matter accumulation amount of the PM filter). .

Patent Document 1 describes an apparatus for regenerating a PM filter. In this apparatus, in a diesel engine, unburned HC is supplied to the catalyst by performing post-injection in which fuel is injected during the expansion stroke of the engine. By using the heat generated by the catalytic reaction of the unburned HC, the particulate matter deposited on the PM filter is burned and removed.

In the case of a diesel engine, the combustion air-fuel ratio is lean, and the exhaust gas contains sufficient oxygen. Therefore, the unburned HC supplied to the catalyst by post-injection is reacted with oxygen by the catalyst, and sufficient heat (particulate matter) It is possible to generate the heat necessary to burn the

However, when the gasoline engine is operated at the stoichiometric air-fuel ratio, since oxygen is hardly contained in the exhaust gas, even if unburned HC is supplied to the catalyst by post injection, the unburned HC reacts less with the catalyst. I can't let you. For this reason, it is difficult to generate sufficient heat to burn the particulate matter, and it is difficult to regenerate the PM filter. Furthermore, there is a possibility that unburned HC that could not be reacted with the catalyst is discharged to the atmosphere and the emission is deteriorated.

In addition, even if the lean combustion is performed to react the unburned HC supplied to the catalyst by post-injection with oxygen in the catalyst, the oxygen contained in the exhaust gas cannot be increased sufficiently due to the limitation of the combustion limit, In some cases, it may not be possible to generate enough heat to burn the particulate matter. Even if the oxygen contained in the exhaust gas can be increased sufficiently, in a system equipped with a three-way catalyst, if the post-injection amount (unburned HC supply amount) is insufficient and oxygen remains, NOx purification becomes difficult. Further, if the post injection amount (the amount of unburned HC supplied) is too large, it becomes difficult to purify the unburned HC with the catalyst, which may cause a deterioration in emissions.

JP 2007-162568 A

This disclosure aims to provide a control device for an internal combustion engine that can achieve both reliable regeneration of a PM filter and prevention of deterioration of emissions.

According to an aspect of the present disclosure, a control device for an internal combustion engine includes a catalyst that purifies exhaust gas of the internal combustion engine, a PM filter that collects particulate matter discharged from the internal combustion engine, and a start-up of the internal combustion engine And a control unit that performs catalyst early warm-up control for controlling the ignition timing to the retard side and controlling the air-fuel ratio to the lean side. The control unit burns the particulate matter collected by the PM filter by the early catalyst warm-up control, and determines whether the filter collected particulate matter has burned a predetermined amount or more. Then, the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned a predetermined amount or more.

Since the exhaust gas purification rate of the catalyst is low until the catalyst is warmed up to the activation temperature after the internal combustion engine is started, the catalyst early warm-up control is executed after the internal combustion engine is started so that the catalyst is warmed up in a short time. ing. In this catalyst early warm-up control, ignition retard control is performed to control the ignition timing to the retard side, and the exhaust temperature is raised. Further, the air-fuel ratio lean control for controlling the air-fuel ratio to the lean side is executed to increase the oxygen contained in the exhaust, thereby promoting the combustion of unburned HC in the exhaust pipe and generating heat, and the catalyst The unburned HC purifying reaction is promoted to generate heat and promote warming up of the catalyst.

The particulate matter collected by the PM filter can be burned by the rise in exhaust temperature and the increase in oxygen in the exhaust by the early catalyst warm-up control.

In the present disclosure, the filter-collected particulate matter is burned by the catalyst early warm-up control to determine whether the filter-collected particulate matter has burned more than a predetermined amount, and the filter-collected particulate matter is more than a prescribed amount. The catalyst early warm-up control is continued until it is determined that combustion has occurred.

In this way, the filter trapped particulate matter can be burned and removed using the increase in exhaust gas temperature and the increase in oxygen in the exhaust gas by the early catalyst warm-up control executed after the internal combustion engine is started. it can. Moreover, even if the catalyst warm-up is completed by the catalyst early warm-up control, the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount. Since the combustion removal of the substance can be continued, the PM filter can be reliably regenerated. Further, only the catalyst early warm-up control executed after the start of the internal combustion engine is used, and the PM filter can be regenerated without deteriorating the emission during the catalyst early warm-up control.

Furthermore, the PM filter can be regenerated whenever the catalyst early warm-up control is executed after the internal combustion engine is started, and the amount of particulate matter accumulated in the PM filter is reduced from the beginning of the operation of the internal combustion engine. Output reduction and fuel consumption deterioration can be suppressed. In addition, sudden regeneration control of the PM filter during operation of the internal combustion engine can be avoided.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a schematic configuration of an engine control system according to a first embodiment of the present disclosure. FIG. 2 is a flowchart showing a flow of processing of the catalyst early warm-up control routine of the first embodiment. FIG. 3 is a flowchart showing the flow of processing of the catalyst early warm-up control routine of the second embodiment. FIG. 4 is a flowchart showing the flow of processing of the catalyst early warm-up control routine of the third embodiment. FIG. 5 is a flowchart showing the flow of processing of the early catalyst warm-up control routine of the fourth embodiment. FIG. 6 is a flowchart showing a process flow of a catalyst early warm-up control routine of the fifth embodiment.

Hereinafter, an embodiment that embodies the form for carrying out the present disclosure will be described.
Example 1
A first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2.

The schematic configuration of the engine control system will be described with reference to FIG.

Engine 11 that is an in-cylinder injection internal combustion engine is an in-cylinder injection gasoline engine that directly injects gasoline as fuel into the cylinder. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the engine 11, and an air flow meter 14 for detecting the intake air amount is provided downstream of the air cleaner 13. A throttle valve 16 whose opening is adjusted by a motor 15 and a throttle position sensor 17 for detecting the position (throttle position) of the throttle valve 16 are provided on the downstream side of the air flow meter 14.

Furthermore, a surge tank 18 is provided on the downstream side of the throttle valve 16, and an intake pipe pressure sensor 19 for detecting the intake pipe pressure is provided in the surge tank 18. The surge tank 18 is provided with an intake manifold 20 that introduces air into each cylinder of the engine 11. Each cylinder of the engine 11 has a fuel injection valve 21 that directly injects fuel (gasoline) into the cylinder. It is attached. In addition, a spark plug 22 is attached to each cylinder of the cylinder head of the engine 11, and the air-fuel mixture in each cylinder is ignited by spark discharge of the spark plug 22 of each cylinder.

On the other hand, the exhaust pipe 23 (exhaust passage) of the engine 11 is provided with a catalyst 24 such as a three-way catalyst for purifying exhaust gas, and the exhaust gas air-fuel ratio or rich gas is respectively provided upstream and downstream of the catalyst 24. / Exhaust gas sensors 31 and 32 (air-fuel ratio sensor, oxygen sensor) for detecting lean etc. are provided. Further, on the downstream side of the catalyst 24 in the exhaust pipe 23 of the engine 11, a GPF (Gasoline Particulate Filter) 25 that collects particulate matter discharged from the engine 11 is provided. The GPF 25 has a temperature environment in which the particulate matter collected by the filter (particulate matter collected by the GPF 25) can be combusted during execution of early catalyst warm-up control, which will be described later, in the exhaust pipe 23 of the engine 11 ( For example, it is disposed downstream of the catalyst 24.

Pressure sensors

33 and 34 for detecting the exhaust pressure are provided on the upstream side and the downstream side of the GPF 25, respectively.

Further, a cooling water temperature sensor 26 for detecting the cooling water temperature and a knock sensor 27 for detecting knocking are attached to the cylinder block of the engine 11. A crank angle sensor 29 that outputs a pulse signal every time the crankshaft 28 rotates by a predetermined crank angle is attached to the outer peripheral side of the crankshaft 28, and the crank angle and the engine are determined based on the output signal of the crank angle sensor 29. The rotation speed is detected.

The outputs of these various sensors are input to an electronic control unit (ECU) 30. The ECU 30 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium), so that the fuel injection amount and the ignition timing are determined according to the engine operating state. The throttle opening (intake air amount) and the like are controlled.

Further, the ECU 30 executes a catalyst early warm-up control routine in FIG. 2 to be described later, so that when a predetermined catalyst early warm-up control execution condition is satisfied after the engine 11 is started, for example, after a cold start, the catalyst early warm-up control routine is executed. Perform warm-up control. In this catalyst early warm-up control, ignition retard control is performed to control the ignition timing to the retard side, and the exhaust temperature is raised. Further, the air-fuel ratio lean control for controlling the air-fuel ratio to the lean side is executed to increase the oxygen contained in the exhaust, thereby promoting the combustion of unburned HC in the exhaust pipe 23 and generating heat. The catalyst 24 promotes the purification reaction of unburned HC to generate heat, thereby promoting the warm-up of the catalyst 24.

It is possible to burn the particulate matter collected by the GPF 25 (particulate matter deposited on the GPF 25) by increasing the exhaust temperature and increasing the oxygen in the exhaust by the early catalyst warm-up control.

The ECU 30 executes a catalyst early warm-up control routine of FIG. 2 to be described later, thereby burning the filter-collected particulate matter (particulate matter collected by the GPF 25) by the catalyst early warm-up control. It is determined whether or not the particulate matter has burned more than a predetermined amount. Then, the ECU 30 continues the early catalyst warm-up control until it is determined that the filter trapped particulate matter has burned a predetermined amount or more. As a result, the particulate matter trapped in the filter is burned and removed by utilizing the rise in exhaust temperature and the increase in oxygen in the exhaust by the early catalyst warm-up control executed after the engine 11 is started.

In the first embodiment, based on the differential pressure between the exhaust pressure on the upstream side of the GPF 25 and the exhaust pressure on the downstream side, it is determined whether or not the filter trapped particulate matter has burned a predetermined amount or more. When the combustion amount of the filter trapped particulate matter increases and the particulate matter accumulation amount of the GPF 25 decreases, the differential pressure between the exhaust pressure upstream of the GPF 25 and the exhaust pressure downstream is reduced. Therefore, by determining whether or not the differential pressure between the exhaust pressure on the upstream side of the GPF 25 and the exhaust pressure on the downstream side is equal to or less than a predetermined value, whether or not the filter trapped particulate matter has burned more than a predetermined amount (of the GPF 25 It is possible to determine whether or not the particulate matter deposition amount has decreased to a predetermined value or less.

Hereinafter, the processing content of the catalyst early warm-up control routine of FIG. 2 executed by the ECU 30 in the first embodiment will be described.

The catalyst early warm-up control routine shown in FIG. 2 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 30, and serves as a control unit.

When this routine is started, first, at step 101, it is determined whether or not the engine 11 has been started. If it is determined in step 101 that the engine 11 has not been started (before the engine 11 has been started), the routine is terminated without executing the processing from step 102 onward.

Thereafter, if it is determined in step 101 above that the engine 11 has been started, the process proceeds to step 102 to determine whether or not the conditions for executing the catalyst early warm-up control are satisfied. It is determined whether the water temperature and the intake air temperature are below a predetermined temperature (that is, after cold start).

If it is determined in step 102 that the conditions for executing the catalyst early warm-up control are not satisfied, this routine is terminated without executing the process for the catalyst early warm-up control in step 103 and subsequent steps.

On the other hand, if it is determined in step 102 that the conditions for executing the catalyst early warm-up control are satisfied, the process proceeds to step 103 to execute the catalyst early warm-up control. In this catalyst early warm-up control, ignition retard control is performed to control the ignition timing to the retard side, and the exhaust temperature is raised. Further, the air-fuel ratio lean control for controlling the air-fuel ratio to the lean side is executed to increase the oxygen contained in the exhaust, thereby promoting the combustion of unburned HC in the exhaust pipe 23 and generating heat. The catalyst 24 promotes the purification reaction of unburned HC to generate heat, thereby promoting the warm-up of the catalyst 24.

During execution of the catalyst early warm-up control, the retard amount of the ignition timing is set so that the filter trapped particulate matter (particulate matter collected by the GPF 25) has an exhaust temperature at which combustion is possible. For example, the retardation amount is set larger than when the filter-collected particulate matter is not burned. As a result, the filter trapped particulate matter is burned and removed by the increase in the exhaust gas temperature and the increase in oxygen in the exhaust gas by the early catalyst warm-up control.

After this, the routine proceeds to step 104 where the exhaust pressure upstream of the GPF 25 (exhaust pressure detected by the pressure sensor 33 upstream of the GPF 25) is read, and the exhaust pressure downstream of the GPF 25 (pressure sensor 34 downstream of the GPF 25). Read the exhaust pressure detected in step 1). In the case of a system in which the exhaust pressure on the downstream side of the GPF 25 is almost atmospheric pressure, the pressure sensor 34 on the downstream side of the GPF 25 is omitted, and the atmospheric pressure detected by the atmospheric pressure sensor (not shown) is You may make it read as downstream exhaust pressure.

Thereafter, the routine proceeds to step 105, where the differential pressure between the exhaust pressure upstream of the GPF 25 and the exhaust pressure downstream is calculated as the differential pressure across the GPF 25, and whether or not the differential pressure across the GPF 25 is below a predetermined value. It is determined whether the particulate matter collected by the filter has burned more than a predetermined amount (whether the particulate matter deposition amount of the GPF 25 has decreased to a predetermined value or less).

If it is determined in step 105 that the differential pressure across the GPF 25 is greater than a predetermined value, it is determined that the filter trapped particulate matter has not yet burned more than a predetermined amount, and the process returns to step 103. The catalyst early warm-up control is continued, and combustion removal of the filter trapped particulate matter is continued.

Thereafter, if it is determined in step 105 that the differential pressure across the GPF 25 is equal to or less than a predetermined value, it is determined that the filter trapped particulate matter has burned more than a predetermined amount, and the process proceeds to step 106 where the catalyst 24 It is determined whether or not the warm-up is complete. For example, whether the duration of the early catalyst warm-up control is a predetermined time or more, whether the temperature of the catalyst 24 (detected value or estimated value) is a predetermined temperature (for example, the activation temperature of the catalyst 24), or the like. It is determined whether or not the catalyst 24 has been warmed up.

If it is determined in step 106 that the warm-up of the catalyst 24 has been completed, the process proceeds to step 107 and the early catalyst warm-up control is terminated. If it is determined in step 106 that the warm-up of the catalyst 24 has not yet been completed, the process returns to step 103 and the early catalyst warm-up control is continued.

In the first embodiment described above, the early catalyst warm-up control is executed when the conditions for executing the early catalyst warm-up control are satisfied after the engine 11 is started (for example, after a cold start). By filtering the particulate matter collected by the filter (particulate matter collected by the GPF 25) by the catalyst early warm-up control, it is determined whether or not the differential pressure across the GPF 25 is equal to or less than a predetermined value. It is determined whether the collected particulate matter has burned more than a predetermined amount. Then, the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount.

In this way, the particulate matter collected by the filter can be burned and removed by utilizing the rise in exhaust temperature and the increase in oxygen in the exhaust by the early catalyst warm-up control executed after the engine 11 is started. it can. Moreover, even if the catalyst 24 has been warmed up earlier by the catalyst early warm-up control, the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount. Since the combustion removal of the particulate matter can be continued, the GPF 25 can be reliably regenerated (the amount of particulate matter deposited on the GPF 25 can be reduced). Further, only the catalyst early warm-up control executed after the engine 11 is started can be used, and the GPF 25 can be regenerated without deteriorating the emission during the catalyst early warm-up control.

Furthermore, the GPF 25 can be regenerated every time the catalyst early warm-up control is executed after the engine 11 is started (for example, every cold start), and the amount of particulate matter accumulated in the GPF 25 is reduced from the beginning of the operation of the engine 11. Thus, a decrease in output of the engine 11 and a deterioration in fuel consumption can be suppressed. In addition, sudden regeneration control of the GPF 25 during operation of the engine 11 can be avoided.

In the first embodiment, the GPF 25 is located at a position (for example, near the downstream of the catalyst 24) in the exhaust pipe 23 of the engine 11 that is in a temperature environment in which the filter trapped particulate matter can combust during execution of the early catalyst warm-up control. The ignition timing retard amount is set so that the filter trapped particulate matter has an exhaust temperature at which combustion is possible during execution of the early catalyst warm-up control. Thereby, the filter trapped particulate matter can be surely burned and removed by the catalyst early warm-up control.
(Example 2)
Next, a second embodiment of the present disclosure will be described with reference to FIG. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In Example 2, a PM sensor (not shown) for detecting particulate matter passing through the GPF 25 is provided on the downstream side of the GPF 25. In this PM sensor, the resistance value between the electrodes changes according to the amount of particulate matter (for example, the weight of the particulate matter and the number of particles) attached to the detection unit, and the output signal changes.

In the second embodiment, the ECU 30 executes a catalyst early warm-up control routine shown in FIG. 3 to be described later, so that the filter trapped particles are based on the output of the PM sensor that detects the particulate matter on the downstream side of the GPF 25. It is determined whether the particulate matter has burned more than a predetermined amount. When the combustion amount of the particulate matter collected by the filter increases and the particulate matter accumulation amount of the GPF 25 decreases to a certain level or less, the particulate matter collection rate of the GPF 25 decreases, and the amount of particulate matter passing through the GPF 25 decreases. To increase. Therefore, by determining whether the output of the PM sensor (or the amount of attached particulate matter estimated based on the output of the PM sensor) is greater than or equal to a predetermined value, the filter trapped particulate matter has burned more than a predetermined amount. (The amount of particulate matter deposited on the GPF 25 has decreased below a predetermined value).

In the catalyst early warm-up control routine of FIG. 3, first, in step 201, it is determined whether or not the engine 11 has been started. If it is determined that the engine 11 has been started, the process proceeds to step 202, where the catalyst It is determined whether an execution condition for the early warm-up control is satisfied.

If it is determined in step 202 that the conditions for executing the catalyst early warm-up control are satisfied, the process proceeds to step 203, where catalyst early warm-up control is executed to promote the warm-up of the catalyst 24, and the filter Burn away the collected particulate matter.

Thereafter, the process proceeds to step 204, and the output of the PM sensor is read. Furthermore, the particulate matter adhesion amount of the PM sensor may be calculated (estimated) based on the output of the PM sensor.

Thereafter, the process proceeds to step 205, and it is determined whether or not the output of the PM sensor (or the particulate matter adhesion amount estimated based on the output of the PM sensor) is equal to or greater than a predetermined value. Is burned more than a predetermined amount (whether the particulate matter accumulation amount of the GPF 25 has decreased to a predetermined value or less).

If it is determined in step 205 that the output of the PM sensor (or the particulate matter adhesion amount estimated based on the output of the PM sensor) is smaller than a predetermined value, the filter trapped particulate matter still has a predetermined amount. It is determined that the combustion has not been performed, and the process returns to step 203, the catalyst early warm-up control is continued, and the combustion removal of the filter trapped particulate matter is continued.

Thereafter, if it is determined in step 205 that the output of the PM sensor (or the particulate matter adhesion amount estimated based on the output of the PM sensor) is equal to or greater than a predetermined value, the particulate matter collected by the filter is located. It is determined that the fuel has burned more than a predetermined amount, and the process proceeds to step 206 to determine whether or not the warm-up of the catalyst 24 is completed. If it is determined in step 206 that the warm-up of the catalyst 24 has been completed, the process proceeds to step 207, where the early catalyst warm-up control is terminated.

In the second embodiment described above, it is determined whether or not the output of the PM sensor (or the particulate matter adhesion amount estimated based on the output of the PM sensor) is equal to or greater than a predetermined value. It is determined whether the substance has burned more than a predetermined amount, and the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount. The same effect as in the first embodiment can be obtained.
Example 3
Next, a third embodiment of the present disclosure will be described with reference to FIG. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In the third embodiment, the ECU 30 executes a catalyst early warm-up control routine shown in FIG. 4 to be described later, thereby determining whether or not the duration of the catalyst early warm-up control is equal to or longer than a predetermined determination time. It is determined whether the particulate matter has burned more than a predetermined amount. As the duration time of the catalyst early warm-up control becomes longer, the combustion amount of the filter trapped particulate matter increases and the particulate matter accumulation amount of the GPF 25 decreases. Therefore, by determining whether or not the duration of the early catalyst warm-up control is equal to or longer than the determination time, it is possible to determine whether or not the filter trapped particulate matter has burned a predetermined amount or more.

In the catalyst early warm-up control routine of FIG. 4, first, in step 301, it is determined whether or not the engine 11 has been started. If it is determined that the engine 11 has been started, the process proceeds to step 302, where the catalyst It is determined whether an execution condition for the early warm-up control is satisfied.

If it is determined in step 302 that the conditions for executing the catalyst early warm-up control are satisfied, the process proceeds to step 303, where catalyst early warm-up control is executed to promote the warm-up of the catalyst 24, and the filter Burn away the collected particulate matter.

Thereafter, the process proceeds to step 304, and the determination time is calculated and set by a map or a mathematical formula based on at least one of the exhaust temperature of the engine 11, the air-fuel ratio, and the oxygen concentration in the exhaust. This determination time is set to a duration of the catalyst early warm-up control necessary for the filter trapped particulate matter to burn more than a predetermined amount or a time slightly longer than that.

The catalyst required for the filter trapped particulate matter to burn more than a predetermined amount because the degree of combustion of the filter trapped particulate matter by the early catalyst warm-up control changes depending on the exhaust temperature, air-fuel ratio, and oxygen concentration in the exhaust. The duration of early warm-up control changes. Therefore, by setting the determination time based on the exhaust temperature, the air-fuel ratio, and the oxygen concentration in the exhaust, the filter trapped particulate matter burns more than a predetermined amount according to the exhaust temperature, the air-fuel ratio, and the oxygen concentration in the exhaust. Corresponding to the change in the duration of the early catalyst warm-up control necessary to change the judgment time, the catalyst early time required for the filter trapped particulate matter to burn more than a predetermined amount It is possible to set the duration of warm-up control or a slightly longer time (appropriate value).

Thereafter, the process proceeds to step 305, where it is determined whether or not the filter trapped particulate matter has burned more than a predetermined amount by determining whether or not the duration of the early catalyst warm-up control is equal to or longer than the determination time.

If it is determined in step 305 that the duration of the early catalyst warm-up control is shorter than the determination time, it is determined that the filter trapped particulate matter has not yet burned a predetermined amount or more, and the above step 303 is performed. Then, the catalyst early warm-up control is continued, and the combustion and removal of the filter trapped particulate matter are continued.

Thereafter, if it is determined in step 305 that the duration of the early catalyst warm-up control is longer than the determination time, it is determined that the filter trapped particulate matter has burned more than a predetermined amount, and the process proceeds to step 306. Then, it is determined whether or not the catalyst 24 has been warmed up. If it is determined in step 306 that the warm-up of the catalyst 24 has been completed, the process proceeds to step 307 and the early catalyst warm-up control is terminated.

In the third embodiment described above, it is determined whether or not the filter trapped particulate matter has burned more than a predetermined amount by determining whether or not the duration of the early catalyst warm-up control is equal to or longer than the determination time. The catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount. The same effect as in the first embodiment can be obtained.

In the third embodiment, the determination time is set based on the exhaust temperature, the air-fuel ratio, and the oxygen concentration in the exhaust gas. However, the determination time is not limited to this, and the determination time is set to a fixed value (for example, filter capture). The maximum value of the duration time of the early catalyst warm-up control necessary for the particulate matter to burn more than a predetermined amount may be used. In this way, the calculation load on the ECU 30 can be reduced.
Example 4
Next, a fourth embodiment of the present disclosure will be described with reference to FIG. Description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In the fourth embodiment, the ECU 30 executes a catalyst early warm-up control routine shown in FIG. 5 to be described later, thereby estimating the combustion amount of the filter-collected particulate matter and estimating the combustion amount of the filter-collected particulate matter. Based on the value, it is determined whether or not the filter trapped particulate matter has burned a predetermined amount or more. That is, it can be determined whether or not the filter trapped particulate matter has burned more than a predetermined amount by determining whether or not the estimated value of the filter trapped particulate matter is greater than or equal to a predetermined value. .

In the catalyst early warm-up control routine of FIG. 5, first, in step 401, it is determined whether or not the engine 11 has been started. If it is determined that the engine 11 has been started, the process proceeds to step 402, where the catalyst It is determined whether an execution condition for the early warm-up control is satisfied.

If it is determined in step 402 that the conditions for executing the catalyst early warm-up control are satisfied, the process proceeds to step 403, where catalyst early warm-up control is executed to promote the warm-up of the catalyst 24, and the filter Burn away the collected particulate matter.

Thereafter, the routine proceeds to step 404 where the combustion amount of the particulate matter collected by the filter is determined based on at least one of the duration of the early catalyst warm-up control, the exhaust temperature of the engine 11, the air-fuel ratio, and the oxygen concentration in the exhaust. It is calculated (estimated) using a map or mathematical formula.

The amount of combustion of the particulate matter collected by the filter due to the early catalyst warm-up control varies depending on the duration of the early catalyst warm-up control, the exhaust gas temperature, the air-fuel ratio, and the oxygen concentration in the exhaust gas. Estimate the amount of particulate matter collected from the filter based on the duration of early catalyst warm-up control, exhaust temperature, air-fuel ratio, and oxygen concentration in the exhaust. Can be estimated.

Thereafter, the process proceeds to step 405, where it is determined whether or not the estimated value of the amount of combustion of the filter trapped particulate matter is greater than or equal to a predetermined value, thereby determining whether or not the filter trapped particulate matter has burned more than a predetermined amount. Determine.

In this step 405, when it is determined that the estimated value of the amount of combustion of the filter-collected particulate matter is smaller than the predetermined value, it is determined that the filter-collected particulate matter has not yet burned more than the predetermined amount. Returning to Step 403, the catalyst early warm-up control is continued, and the combustion and removal of the filter trapped particulate matter are continued.

Thereafter, if it is determined in step 405 that the estimated value of the amount of combustion of the filter-collected particulate matter is greater than or equal to a predetermined value, it is determined that the filter-collected particulate matter has burned more than a predetermined amount, Proceeding to step 406, it is determined whether or not the catalyst 24 has been warmed up. If it is determined in step 406 that the warm-up of the catalyst 24 has been completed, the process proceeds to step 407, where the early catalyst warm-up control is terminated.

In the fourth embodiment described above, it is determined whether or not the estimated value of the combustion amount of the filter-collected particulate matter is greater than or equal to a predetermined value, so that whether or not the filter-collected particulate matter has burned more than a predetermined amount. The catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than a predetermined amount. Even in this case, substantially the same effect as in the first embodiment can be obtained.
(Example 5)
Next, a fifth embodiment of the present disclosure will be described with reference to FIG. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In the fifth embodiment, temperature sensors (not shown) for detecting the exhaust temperature are provided on the upstream side and the downstream side of the GPF 25, respectively.

In the fifth embodiment, the ECU 30 executes a catalyst early warm-up control routine shown in FIG. 6 to be described later, so that the filter capture is performed based on the temperature difference between the exhaust temperature upstream of the GPF 25 and the exhaust temperature downstream. It is determined whether or not the particulate matter has burned more than a predetermined amount. When the combustion amount of the particulate matter collected by the filter increases and the particulate matter accumulation amount of the GPF 25 decreases below a certain level, the amount of heat generated by the combustion of the particulate matter in the GPF 25 decreases, and the upstream side of the GPF 25 The temperature difference (absolute value) between the exhaust gas temperature and the downstream exhaust gas temperature becomes small. Therefore, by determining whether or not the temperature difference between the exhaust temperature on the upstream side of the GPF 25 and the exhaust temperature on the downstream side is equal to or less than a predetermined value, it is determined whether or not the filter trapped particulate matter has burned more than a predetermined amount. Can be determined.

In the catalyst early warm-up control routine of FIG. 6, first, in step 501, it is determined whether or not the engine 11 has been started. If it is determined that the engine 11 has been started, the process proceeds to step 502, where the catalyst It is determined whether an execution condition for the early warm-up control is satisfied.

If it is determined in step 502 that the conditions for executing the catalyst early warm-up control are satisfied, the process proceeds to step 503, where catalyst early warm-up control (ignition delay control and air-fuel ratio lean control) is executed, While promoting the warm-up of the catalyst 24, the particulate matter collected by the filter is burned and removed.

Thereafter, the process proceeds to step 504, in which the exhaust temperature upstream of the GPF 25 (the exhaust temperature detected by the temperature sensor upstream of the GPF 25) is read, and the exhaust temperature downstream of the GPF 25 (detected by the temperature sensor downstream of the GPF 25). Read the exhaust temperature). The exhaust temperature on the upstream side of the GPF 25 may be estimated based on the operating state of the engine 11, the temperature of the catalyst 24 (detected value or estimated value), and the like.

Thereafter, the process proceeds to step 505, where the temperature difference (absolute value) between the exhaust temperature upstream of the GPF 25 and the exhaust temperature downstream is calculated as the temperature difference before and after the GPF 25, and the temperature difference before and after the GPF 25 is a predetermined value. By determining whether or not it is below, it is determined whether or not the filter trapped particulate matter has burned a predetermined amount or more.

If it is determined in step 505 that the temperature difference before and after the GPF 25 is greater than a predetermined value, it is determined that the filter trapped particulate matter has not yet burned more than a predetermined amount, and the process returns to step 503. Then, the catalyst early warm-up control is continued to continue the combustion removal of the filter trapped particulate matter.

Thereafter, if it is determined in step 505 that the temperature difference before and after the GPF 25 is equal to or less than a predetermined value, it is determined that the filter trapped particulate matter has combusted a predetermined amount or more, and the process proceeds to step 506. It is determined whether or not 24 warm-up has been completed. If it is determined in step 506 that the warm-up of the catalyst 24 has been completed, the process proceeds to step 507 and the early catalyst warm-up control is terminated.

In the fifth embodiment described above, it is determined whether or not the temperature difference before and after the GPF 25 is equal to or less than a predetermined value, thereby determining whether or not the filter trapped particulate matter has burned more than a predetermined amount. The catalyst early warm-up control is continued until it is determined that the collected particulate matter has burned more than a predetermined amount. Even if it does in this way, the effect similar to the said Example 1 can be acquired.

It should be noted that the above-mentioned Examples 1 to 5 are appropriately combined, and the differential pressure across the GPF 25, the output of the PM sensor, the duration of the early catalyst warm-up control, and the estimated value of the combustion amount of the filter trapped particulate matter Based on two or more determination parameters of the temperature difference before and after the GPF 25, it may be determined whether or not the filter trapped particulate matter has burned a predetermined amount or more.

In addition, the determination parameters used in the above Examples 1 to 5 (GPF 25 differential pressure, PM sensor output, catalyst early warm-up control duration, estimated amount of filter particulate matter combustion amount, GPF 25 It is not limited to the temperature difference between before and after, and whether or not the filter trapped particulate matter has burned more than a predetermined amount based on other determination parameters (parameters correlated with the amount of filter trapped particulate matter) You may make it determine.

In each of the first to fifth embodiments, the present disclosure is applied to a direct injection gasoline engine. However, the present disclosure is not limited to this, and a catalyst for purifying engine exhaust gas and particulate matter discharged from the engine are collected. As long as the system includes a PM filter, the present disclosure can be applied to a diesel engine or an intake port injection gasoline engine.

Claims

A catalyst (24) for purifying exhaust gas from the internal combustion engine (11), a PM filter (25) for collecting particulate matter discharged from the internal combustion engine (11), and after starting the internal combustion engine (11) In a control device for an internal combustion engine, comprising a control unit (30) for performing catalyst early warm-up control for controlling the ignition timing to the retard side and controlling the air-fuel ratio to the lean side,
Whether the control unit (30) burns the particulate matter collected by the PM filter (25) by the catalyst early warm-up control, and the filter-collected particulate matter is burned more than a predetermined amount. And the catalyst early warm-up control is continued until it is determined that the filter trapped particulate matter has burned more than the predetermined amount.
The control unit (30) determines whether the filter-collected particulate matter has burned more than the predetermined amount based on the differential pressure between the upstream exhaust pressure and the downstream exhaust pressure of the PM filter (25). The control apparatus for an internal combustion engine according to claim 1, wherein:
The control unit (30) determines whether or not the filter trapped particulate matter has burned more than the predetermined amount based on an output of a PM sensor that detects the particulate matter on the downstream side of the PM filter (25). The control apparatus for an internal combustion engine according to claim 1 or 2, wherein
The control unit (30) determines whether the filter trapped particulate matter has burned more than the predetermined amount depending on whether the duration time of the catalyst early warm-up control is longer than a predetermined determination time. The control device for an internal combustion engine according to any one of claims 1 to 3.
The control unit (30) sets the determination time based on at least one of an exhaust temperature, an air-fuel ratio, and an oxygen concentration in the exhaust gas of the internal combustion engine (11). The internal combustion engine control device described.
The control unit (30) estimates a combustion amount of the filter-collected particulate matter, and the filter-collected particulate matter is the predetermined amount based on an estimated value of the combustion amount of the filter-collected particulate matter. 6. The control apparatus for an internal combustion engine according to claim 1, wherein it is determined whether or not combustion has been performed.
The control unit (30) includes the filter-collected particles based on at least one of a duration of the early catalyst warm-up control, an exhaust temperature of the internal combustion engine (11), an air-fuel ratio, and an oxygen concentration in the exhaust. The control apparatus for an internal combustion engine according to claim 6, wherein a combustion amount of the particulate matter is estimated.
The control unit (30) determines whether or not the filter trapped particulate matter has burned more than the predetermined amount based on a temperature difference between the upstream exhaust temperature and the downstream exhaust temperature of the PM filter (25). The control apparatus for an internal combustion engine according to any one of claims 1 to 7, characterized in that
The PM filter (25) is disposed in a position in the exhaust passage (23) of the internal combustion engine (11) at a temperature environment where the filter-collected particulate matter can be combusted during execution of the early catalyst warm-up control. 9. The control device for an internal combustion engine according to claim 1, wherein the control device is an internal combustion engine.
The control unit (30) sets the retard amount of the ignition timing so that the filter trapped particulate matter becomes an exhaust temperature at which the filter trapped particulate matter can burn during execution of the catalyst early warm-up control. The control device for an internal combustion engine according to any one of claims 1 to 9.