JP2019183672A - Exhaust emission control device - Google Patents

Abstract

To appropriately regenerate a trapping filter for trapping particulate matters, without giving influences to fuel economy.SOLUTION: An exhaust emission control device includes a catalyst (16) for purifying exhaust gas from an engine (2), a GPF (17) for trapping particulate matters in the exhaust gas from the engine, and an ECU (3) for performing the deterioration diagnosis of the catalyst and the regeneration control of the trapping filter. When determining to perform the regeneration of the GPF, the ECU executes rich combustion and lean combustion to perform the deterioration diagnosis of the catalyst, and executes ignition delay during the rich combustion to perform the regeneration of the trapping filter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust emission control device.

  In a vehicle equipped with an engine, a PM filter that collects particulate matter (PM: particulate matter) in exhaust gas discharged from the engine may be provided. In such a PM filter, regeneration control of the PM filter is periodically performed to prevent clogging (see, for example, Patent Document 1).

  In Patent Document 1, during the early warm-up control of the catalyst, the ignition retard angle and the air-fuel ratio are made lean so that the PM in the PM filter is burned and removed, and the PM filter is regenerated.

JP-A-2015-183607

  However, in Patent Document 1, there is a possibility that the exhaust gas performance of the engine may be deteriorated by performing the ignition retard and the lean air-fuel ratio for early warm-up control of the catalyst, and improvement has been desired.

  The present invention has been made in view of the above points, and an object thereof is to provide an exhaust purification device that can appropriately regenerate a collection filter that collects particulate matter without affecting exhaust gas performance. And

  An exhaust emission control device according to an aspect of the present invention includes a catalyst that purifies engine exhaust, a collection filter that collects particulate matter in the exhaust of the engine, a deterioration diagnosis of the catalyst, and regeneration of the collection filter A control device that performs control, and when the control device determines to regenerate the collection filter, the control device performs rich combustion and lean combustion to perform deterioration diagnosis of the catalyst, and The collection filter is regenerated by performing an ignition retard at the time of combustion.

  ADVANTAGE OF THE INVENTION According to this invention, the collection filter which collects a particulate matter can be reproduced | regenerated appropriately, without affecting a fuel consumption.

1 is an overall configuration diagram of an engine control system according to the present embodiment. It is a flowchart of catalyst deterioration diagnosis and GPF regeneration control according to the present embodiment. 6 is a time chart showing changes with time of the air-fuel ratio and ignition timing in the present embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, a four-wheeled vehicle will be described as an example of a vehicle to which the engine control system according to the present invention is applied. However, the application target is not limited to this and can be changed. For example, the present invention may be applied to other types of vehicles such as motorcycles.

  An 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, an engine control system 1 according to the present embodiment is configured to control an operation of an engine 2 as an internal combustion engine and its peripheral configuration by an ECU (Electronic Control Unit) 3. . Although details will be described later, the ECU 3 constitutes the control 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 includes a crankshaft 20 in a crankcase (not shown), and includes a cylinder 21, a cylinder head 22, and the like.

  A piston 23 is accommodated in the cylinder 21 so as to reciprocate 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 as the piston 23 reciprocates in a predetermined direction.

  The internal space of the cylinder head 22 constitutes a 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 27 a and an exhaust port 27 b that communicate with the combustion chamber 25. 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 cam chain (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 a predetermined timing.

  The 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 constitute an intake passage for intake air. In the middle of the intake pipe 10, an air cleaner 11, a throttle valve 12, and a surge tank 13 are provided 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) flowing through the intake pipe 10 through the air cleaner 11 and outputs the detected value to the ECU 3.

  The throttle valve 12 is configured to include, for example, a butterfly valve, and adjusts the flow rate (intake air amount) of the intake air flowing through the intake pipe 10 by being opened and closed according to a command from the ECU 3. The surge tank 13 has a sufficiently large volume compared to the intake pipe 10 and prevents pulsation of 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 intake air amount and the 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 that injects fuel. The injector 14 injects a predetermined amount of fuel into the intake pipe 10 (or the intake port 27a) according to a command from the ECU 3. That is, the engine 2 according to the present embodiment is a so-called port injection type engine.

  The exhaust pipe 15 is connected to the downstream end of the exhaust port 27b via an exhaust manifold (not shown). The exhaust port 27b and the passage in the intake pipe 10 constitute an exhaust passage for exhaust gas. A catalyst 16 that purifies the exhaust (exhaust gas) of the engine 2 is provided in the middle of the exhaust pipe 15 as a part of the exhaust purification device. The catalyst 16 is composed of, for example, a three-way catalyst, and converts pollutants (carbon monoxide, 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 as the catalyst 16.

  A first exhaust gas sensor 16a and a second exhaust gas sensor 16b that detect a predetermined component in the exhaust gas are disposed before and after the catalyst 16 (upstream and downstream). The first exhaust gas sensor 16a may be referred to as an upstream sensor, and the second exhaust gas sensor 16b may be referred to as a downstream sensor. The first exhaust gas sensor 16a and the second exhaust gas sensor 16b are constituted by, for example, zirconia oxygen sensors, and their outputs (current values) change according to the oxygen concentration in the exhaust gas. The first exhaust gas sensor 16a and the second exhaust gas sensor 16b output detected values (current values) to the ECU 3. The first exhaust gas sensor 16a and the second exhaust gas sensor 16b are not limited to oxygen sensors, and may be air-fuel ratio sensors that detect the air-fuel ratio of exhaust gas flowing before and after the catalyst 16, for example.

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

  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 clogged state of the GPF 17 from the pressure difference, that is, the amount of collected PM.

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

  Further, the engine 2 is provided with a water temperature sensor 42 that detects the engine water temperature and a crank sensor 43 that detects the phase of the crankshaft 20. The detection values of the water temperature sensor 42 and the crank sensor 43 are output to the ECU 3. The engine speed can be calculated from the output of the crank sensor 43.

  Further, the vehicle is provided with a vehicle speed sensor 44 that detects 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 that generates a braking force on the vehicle, and outputs a predetermined electrical signal corresponding to the amount of depression (stepping force) to the ECU 3. The accelerator pedal 46 constitutes acceleration means for generating acceleration force on the vehicle, and outputs a predetermined electrical signal corresponding to the amount of depression (stepping force) to the ECU 3.

  The ECU 3 controls the overall operation of the vehicle including various configurations inside and outside the engine 2. The ECU 3 includes a processor that executes various processes, a memory, and the like. The memory is configured by a storage medium such as a ROM (Read Only Memory) or a RAM (Random Access Memory) according to the application. The memory stores a control program for controlling the various configurations described above.

  For example, the ECU 3 determines the state of the vehicle from various sensors provided in the vehicle, and controls driving of the spark plug 26, the injector 14, the throttle valve 12, and the like. Although details will be described later, the ECU 3 performs deterioration diagnosis of the catalyst 16 based on the temperature of the catalyst 16 and the air-fuel ratio before and after the catalyst, and further performs regeneration control of the GPF 17 based on the temperature of the GPF 17 and the PM accumulation amount. To do. The ECU 3 stores a predetermined threshold value in advance in order to perform the above control.

  The exhaust emission control device in the present embodiment includes the above-described engine 2 and its peripheral components (catalyst 16, GPF 17, ECU 3, various sensors, etc.).

  By the way, in the exhaust purification system for a vehicle engine, the PF that collects PM in the exhaust gas can be clogged due to the accumulation of PM. For this reason, so-called filter regeneration control is performed in which clogging of the PF is eliminated by raising the temperature of the PF and burning PM.

  As this type of control, for example, when the amount of accumulated PM in the PF becomes a predetermined amount or more, there is a type in which the ignition timing of the engine is delayed later than usual and fuel is burned on the exhaust downstream side. As a result, the temperature of the PF is raised and the engine is lean-burned so that the residual oxygen concentration in the exhaust pipe around the PF increases, so that the PM in the PF is burned and the PF is regenerated.

  However, if the ignition timing is simply retarded for PF regeneration, fuel consumption and exhaust gas performance may be deteriorated.

  Accordingly, the present inventors have conceived the present invention by paying attention to controlling the engine so that rich combustion and lean combustion are repeated on the exhaust downstream side when performing catalyst deterioration diagnosis. Specifically, in this embodiment, when the ECU 3 determines that the regeneration of the GPF 17 is to be performed, the ECU 3 performs rich combustion and lean combustion to perform the deterioration diagnosis of the catalyst 16, and the ignition delay angle is determined during the rich combustion. By performing the above, the GPF 17 is reproduced. That is, the gist of the present invention is to match the timing of performing the deterioration diagnosis of the catalyst 16 with the timing of performing the regeneration control of the GPF 17.

  According to this configuration, it is possible to simultaneously perform the deterioration diagnosis of the catalyst 16 and the regeneration control of the GPF 17 by performing the ignition retard at the time of rich combustion in the deterioration diagnosis of the catalyst 16. For this reason, compared with the case where the deterioration diagnosis of the catalyst 16 and the regeneration control of the GPF 17 are performed separately, it is possible to suppress deterioration of fuel consumption and exhaust gas performance. Further, since the exhaust gas of the engine 2 can be raised in temperature by performing the ignition retard, even when the oxidation reaction of the catalyst 16 is small due to deterioration of the catalyst 16, the regeneration of the GPF 17 is appropriately performed. Is possible.

  Further, when performing the ignition delay, it is preferable to increase the fuel injection amount and the intake air amount based on the required torque of the occupant and the retardation amount of the ignition delay. In this case, even if the output decreases due to the ignition delay, the decrease can be corrected. Therefore, it is possible to travel the vehicle with the occupant's required torque while raising the temperature of the GPF 17 by the ignition delay angle, and it is possible to prevent a decrease in traveling performance due to the regeneration of the GPF 17.

  Next, a control flow according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart of catalyst deterioration diagnosis and GPF regeneration control according to the present embodiment. In the flow shown below, unless otherwise specified, the subject of the operation (calculation (calculation), determination, etc.) is the ECU.

  As shown in FIG. 2, when the control is started, in step ST101, the ECU 3 determines whether or not the warm-up of the catalyst 16 has been completed. The warm-up refers to a state where the catalyst has risen to an activation temperature at which exhaust gas can be purified. The ECU 3 can determine the completion of warming-up of the catalyst 16 from the temperature of the exhaust gas flowing in the vicinity of the catalyst 16, the temperature of the GPF 17 (detected values of the temperature sensors 18a and 18b), and the like. When warming up of the catalyst 16 is completed (step ST101: YES), the process proceeds to step ST102. When the warm-up of the catalyst 16 is not completed (step ST101: NO), the process of step ST101 is repeated.

  In step ST102, the ECU 3 determines whether or not the PM accumulation amount in the GPF 17 is equal to or greater than a specified amount. The PM accumulation amount can be predicted from, for example, a detection value of the differential pressure sensor 19. If the PM deposition amount is greater than or equal to the prescribed amount (step ST102: YES), it is determined that the GPF 17 needs to be regenerated, and the process proceeds to step ST103. If the PM deposition amount is less than the specified amount (step ST102: NO), the control is terminated assuming that regeneration of the GPF 17 is unnecessary.

  In step ST103, the ECU 3 starts deterioration diagnosis of the catalyst 16 and regeneration control of the GPF 17. Then, the process proceeds to step ST104.

  In step ST104, the ECU 3 performs rich combustion control. For example, the ECU 3 increases the fuel injection amount or decreases the intake air amount, thereby generating an air-fuel mixture with a high air-fuel ratio and causing the engine 2 to perform rich combustion. Then, the process proceeds to step ST105.

  In step ST105, the ECU 3 determines whether or not the first exhaust gas sensor 16a has detected a rich state of exhaust gas. For example, the ECU 3 determines rich when the oxygen concentration in the exhaust gas is equal to or lower than a predetermined concentration, and determines lean when the oxygen concentration is higher than the predetermined concentration. When the first exhaust gas sensor 16a detects the rich state (step ST105: YES), the process proceeds to step ST106. When the first exhaust gas sensor 16a detects a lean state (step ST105: NO), the process returns to step ST104.

  In step ST106, the ECU 3 determines whether or not the temperature of the GPF 17 is equal to or lower than a predetermined temperature. This predetermined temperature is a temperature at which PM collected by the PF can be combusted. When the temperature of the GPF 17 is equal to or lower than the predetermined temperature (step ST106: YES), the process proceeds to step ST107. When the temperature of the GPF 17 is higher than the predetermined temperature (step ST106: NO), the process proceeds to step ST109.

  In step ST107, the ECU 3 performs ignition retard control. Specifically, the ECU 3 controls the spark plug 26 so as to retard the ignition timing by a predetermined retardation amount. Then, the process proceeds to step ST108.

  In step ST108, the ECU 3 determines whether or not the temperature of the GPF 17 is equal to or higher than a predetermined temperature. When the temperature of the GPF 17 is equal to or higher than the predetermined temperature (step ST108: YES), the process proceeds to step ST109. When the temperature of GPF 17 is lower than the predetermined temperature (step ST108: NO), the process returns to step ST107.

  In step ST109, the ECU 3 returns the ignition timing to normal. That is, the ECU 3 sets the retard amount of the ignition retard to zero. Then, the process proceeds to step ST110.

  In step ST110, the ECU 3 determines whether or not the second exhaust gas sensor 16b has detected an exhaust gas rich state. For example, the ECU 3 determines rich when the oxygen concentration in the exhaust gas is equal to or higher than a predetermined concentration, and determines lean when the oxygen concentration is less than the predetermined concentration. When the second exhaust gas sensor 16b detects the rich state (step ST110: YES), the process proceeds to step ST111. When the second exhaust gas sensor 16b detects a lean state (step ST110: NO), the process of step ST110 is repeated.

  In step ST111, the ECU 3 performs lean combustion control. For example, the ECU 3 reduces the fuel injection amount or increases the intake air amount, thereby generating an air-fuel mixture with a low (small) air-fuel ratio and causing the engine 2 to perform lean combustion. Then, the process proceeds to step ST112.

  In step ST112, the ECU 3 determines whether or not both the first exhaust gas sensor 16a and the second exhaust gas sensor 16b have detected the lean state of the exhaust gas. When both the first exhaust gas sensor 16a and the second exhaust gas sensor 16b detect the lean state of the exhaust gas (step ST112: YES), the time from the lean detection of the first exhaust gas sensor 16a to the lean detection of the second exhaust gas sensor 16b Is shorter than the predetermined time, the ECU 3 determines that the catalyst 16 has deteriorated, and the control ends. In this case, if the time from the lean detection of the first exhaust gas sensor 16a to the lean detection of the second exhaust gas sensor 16b is equal to or longer than a predetermined time, the ECU 3 determines that the catalyst 16 has not deteriorated and performs control. Ends. On the other hand, when both the first exhaust gas sensor 16a and the second exhaust gas sensor 16b do not detect the lean state of the exhaust gas (step ST112: NO), the process returns to step ST111.

  As described above, in the present embodiment, the ignition delay is performed so as to increase the temperature of the GPF 17 during the rich combustion of the air-fuel ratio in the deterioration diagnosis control of the catalyst 16. As a result, it is possible to burn and remove the PM deposited on the GPF 17 during the air-fuel ratio lean combustion in the deterioration diagnosis control of the catalyst 16. That is, by making the deterioration diagnosis of the catalyst 16 and the regeneration control of the GPF 17 proceed at the same time, it is possible to suppress deterioration in fuel consumption and exhaust gas performance as compared with the case where each control is performed separately. Further, the time required for the control can be shortened by performing the two controls simultaneously.

  In the present embodiment, as described above, the temperature of the GPF 17 is determined in steps ST106 and ST108, and the retard amount of the ignition delay is controlled in steps ST107 and ST109 based on the result. That is, the ECU 3 sets the retard amount of the ignition retard according to the temperature of the GPF 17. At this time, it is preferable that the retard amount of the ignition retard is set to be larger as the difference between the current temperature of the GPF 17 and the target temperature that is the combustible temperature of PM is larger.

  According to this configuration, for example, when the temperature of the GPF 17 is relatively low, that is, when the difference between the current temperature of the GPF 17 and the target temperature is larger than a predetermined value, the temperature of the GPF 17 is increased by increasing the retard amount. It is possible to increase. On the other hand, when the temperature of the GPF 17 is relatively high, that is, when the difference between the current temperature of the GPF 17 and the target temperature is equal to or less than a predetermined value, the amount of retardation is made relatively small, so It is possible to appropriately regenerate the GPF 17 while preventing the temperature.

  Next, with reference to FIG. 3, changes with time in the air-fuel ratio and the ignition timing when the control according to the present embodiment is applied will be described. FIG. 3 is a time chart showing temporal changes in the air-fuel ratio and ignition timing in the present embodiment. In FIG. 3, the horizontal axis indicates time, and the vertical axis indicates air-fuel ratio and ignition timing in order from the top. Note that the time chart shown in FIG. 3 is merely an example, and is not limited to this, and can be changed as appropriate.

  As shown in FIG. 3, at the start of this control, the air-fuel ratio is controlled to the target air-fuel ratio, and the ignition timing is controlled to the normal ignition timing. After the deterioration diagnosis of the catalyst 16 and the regeneration control of the GPF 17 are started, the ECU 3 performs rich combustion control at the timing of T1, for example, increases the fuel injection amount.

  Thereafter, when the richness of the air-fuel ratio is detected by the first exhaust gas sensor 16a at the timing of T2 during the rich combustion control, the ECU 3 performs the ignition delay control and retards the ignition timing by a predetermined delay amount. Thereafter, the exhaust gas temperature can be raised by retarding the ignition timing, and the GPF 17 can be raised. As a result, the PM deposited on the GPF 17 can be burned and removed.

  Thereafter, when the richness of the air-fuel ratio is detected by the second exhaust gas sensor 16b at the timing of T3, the ECU 3 switches from rich combustion control to lean combustion control, for example, reduces the fuel injection amount. At the same time, the ECU 3 returns the ignition timing to the normal ignition timing.

  Thereafter, when the air-fuel ratio lean is detected by the second exhaust gas sensor 16b at the timing of T4, the ECU 3 controls the air-fuel ratio to return to the target air-fuel ratio. Thereby, the deterioration diagnosis of the catalyst 16 becomes possible. Thereafter, if regeneration of the GPF 17 is not completed, rich fuel control is performed again. In addition, in FIG. 3, although the case where the ignition timing is returned to normal at the timing of switching to lean combustion (ignition retardation is stopped) has been described, the present invention is not limited to this. For example, the ignition delay may be stopped before T3 if it can be determined that the regeneration of the GPF 17 has been completed by raising the temperature of the GPF 17 to a predetermined temperature before T3. Thereby, the excessive temperature rise of GPF17 can be suppressed.

  As described above, in the present embodiment, the ignition delay is performed during the rich combustion, and the deterioration diagnosis of the catalyst 16 and the regeneration control of the GPF 17 are performed at the same time. It is possible to properly reproduce the GPF 17 without affecting the process.

  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 engine 2 may be used.

  Moreover, although the said embodiment demonstrated the gasoline engine as an example, it is not limited to this. This control can be applied even to a diesel engine.

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

  Further, in the above embodiment, the case where the ignition timing is returned to normal (ignition delay is stopped) before the second exhaust gas sensor 16b detects rich in the flow shown in FIG. 2 has been described. It is not limited. For example, the ignition retard may be stopped when the second exhaust gas sensor 16b detects rich after the first exhaust gas sensor 16a detects rich. According to this configuration, it is possible to determine whether or not the ignition delay is performed based on the detection of rich by the first exhaust gas sensor 16a and the second exhaust gas sensor 16b, and output reduction (torque reduction) accompanying the ignition delay. Can be suppressed.

  Moreover, although this Embodiment and the modified example were demonstrated, what combined the said embodiment and modified example entirely or partially as another embodiment of this invention may be sufficient.

  The embodiments of the present invention are not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way by technological advancement or other derived technology, the method may be used. Accordingly, the claims cover all embodiments that can be included within the scope of the technical idea of the present invention.

  As described above, the present invention has an effect that the collection filter that collects particulate matter can be appropriately regenerated without affecting the fuel consumption. Useful.

1: Control system 2: Engine 3: ECU
10: Intake pipe 11: Air cleaner 12: Throttle valve 13: Surge tank 14: Injector 15: Exhaust pipe 16: Catalyst 16a: First exhaust gas sensor 16b: Second exhaust gas sensor 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 27a: intake port 27b: exhaust port 28a: intake valve 28b: exhaust valve 29a: intake camshaft 29b: exhaust cam Shaft 40: Air amount sensor 41: Intake pressure sensor 42: Water temperature sensor 43: Crank sensor 44: Vehicle speed sensor 45: Brake pedal 46: Accelerator pedal

Claims (4)

A catalyst that purifies the engine exhaust,
A collection filter for collecting particulate matter in the exhaust of the engine;
A controller for performing deterioration diagnosis of the catalyst and regeneration control of the collection filter,
When it is determined that the collection filter is to be regenerated, the control device performs rich combustion and lean combustion to perform deterioration diagnosis of the catalyst, and performs ignition delay in the rich combustion. An exhaust emission control device for regenerating the collection filter.   2. The exhaust gas purification according to claim 1, wherein when the ignition delay is performed, the fuel injection amount and the intake air amount are increased based on a passenger's required torque and a retard amount of the ignition delay. apparatus. A first exhaust gas sensor disposed upstream of the catalyst;
A second exhaust gas sensor disposed on the downstream side of the catalyst,
The control device performs deterioration diagnosis of the catalyst based on outputs of the first exhaust gas sensor and the second exhaust gas sensor;
3. The exhaust gas purification according to claim 1, wherein the ignition delay is stopped when the second exhaust gas sensor detects rich after the first exhaust gas sensor detects rich. 4. apparatus.   The exhaust gas purification according to any one of claims 1 to 3, wherein a retard amount of the ignition retard is set to be larger as a difference between a current temperature of the collection filter and a target temperature is larger. apparatus.

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