JP7302541B2 - exhaust treatment system - Google Patents

Description

The present invention relates to deterioration determination of an exhaust treatment system that includes a catalyst that purifies exhaust gas and a fuel addition device that adds fuel to the catalyst.

An exhaust treatment device is provided in an exhaust pipe to purify particulate matter (PM) in the exhaust of a diesel engine or the like. This exhaust treatment device includes, for example, a PM removal filter that collects particulate matter, and an oxidation catalyst (DOC: Diesel Oxidation Catalyst) arranged upstream of the PM removal filter in the flow of exhaust gas. When the amount of particulate matter accumulated in the PM removal filter increases, the filter clogs and the exhaust purification function deteriorates. Then, regeneration of a so-called PM removal filter is performed.

To regenerate the PM removal filter, fuel is added to the exhaust using a fuel addition device or the like, and the added fuel is reacted with an oxidation catalyst. warm up. Then, the high-temperature exhaust gas flows through the PM removal filter, thereby raising the temperature of the PM removal filter and burning the PM in the PM removal filter.

In the exhaust treatment device having such a configuration, if clogging occurs in the fuel addition device or deterioration of the catalyst or PM removal filter occurs, the PM removal filter may not be able to reach the target temperature. Therefore, when the PM removal filter cannot reach the target temperature, it is required to determine whether clogging has occurred in the fuel addition device or whether the catalyst has deteriorated.

For example, Japanese Patent Application Laid-Open No. 2009-228589 (Patent Document 1) discloses that when the temperature of the catalyst exhaust gas is below a predetermined value, a command is given to the fuel injection valve for post-injection, and if the temperature of the catalyst exhaust gas does not rise above a predetermined value, an exhaust process is performed. A technique is disclosed for determining that an oxidation catalyst, which is a device, is abnormal, and determining that a fuel addition device is abnormal when the catalyst exhaust temperature rises above a predetermined value.

JP 2009-228589 A

However, the deterioration state of the fuel addition device and the deterioration state of the exhaust treatment device cannot always be determined with high accuracy based only on the catalyst exhaust temperature, and further improvement in the determination accuracy is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and its object is to accurately detect the deterioration of an exhaust treatment device that purifies exhaust gas and the deterioration of a fuel addition device that adds fuel to the exhaust treatment device. An object of the present invention is to provide an exhaust treatment system that judges highly.

An exhaust treatment system according to one aspect of the present invention is an exhaust treatment system that purifies exhaust from an engine having cylinders. The exhaust treatment system is provided in an exhaust passage of an engine and includes an exhaust treatment device that raises the temperature by heat of reaction with fuel in the exhaust, a first detection device that detects a first temperature of the exhaust flowing into the exhaust treatment device, a second detection device that detects a second temperature of exhaust gas flowing out of the exhaust treatment device; a fuel addition device that is provided upstream of the exhaust treatment device in the exhaust passage and adds fuel to the exhaust passage; A fuel supply device that supplies fuel to the interior thereof, and a control device that controls the fuel addition device and the fuel supply device using a first temperature rise amount indicated by the difference between the first temperature and the second temperature. The control device sets the first target value using a predetermined relationship between the operating state of the engine and the first target value of the first temperature rise allowance corresponding to the operating state and the operating state. The control device uses the difference between the first measured value of the first temperature increase due to the post-injection using the fuel supply device and the first target value corresponding to the operating state when the first measured value is detected to control the exhaust gas. A first learned value indicating the degree of deterioration of the processing device is calculated. The control device uses the second measured value of the first temperature increase due to addition of fuel using the fuel addition device, the first target value, and the first learning value to indicate the degree of deterioration of the fuel addition device. 2 Calculate the learning value.

By doing so, the first learning value indicating the degree of deterioration of the exhaust treatment device can be calculated with high accuracy by performing the post-injection (that is, without using the fuel addition device). Furthermore, by using the calculated first learned value, the second learned value indicating the degree of deterioration of the fuel addition device can be calculated with high accuracy. Therefore, deterioration of the exhaust treatment device and deterioration of the fuel addition device can be determined with high accuracy.

Preferably, the exhaust treatment device is an oxidation catalyst. The exhaust treatment system is provided at a position downstream of the oxidation catalyst, and includes a filter that collects particulate matter contained in the exhaust gas flowing through the exhaust passage, and a third detector that detects a third temperature of the exhaust gas that flows out from the filter. and a device. The control device sets a first target value and a second target value of the second temperature increase indicated by the difference between the second temperature and the third temperature, corresponding to the operating state. The control device performs the first learning using the difference between the first measured value and the first target value due to the post-injection and the difference between the third measured value and the second target value of the second temperature increase due to the post-injection. Calculate the value. The control device calculates a second measured value, a fourth measured value of a second temperature increase due to addition of fuel using the fuel addition device, a first target value, a second target value, and a first learned value. is used to calculate the second learning value.

With this configuration, even when the exhaust treatment device is an oxidation catalyst and the filter is provided downstream of the oxidation catalyst, the first learned value can be calculated with high accuracy.

More preferably, the control device responds to the operating state using a predetermined relationship among the amount of fuel supplied by post-injection, the temperature of the exhaust gas flowing into the exhaust treatment device, and the flow rate of the gas passing through the exhaust treatment device. Set the first target value to be set.

With this configuration, the first temperature increase margin corresponding to the operating state of the engine based on the amount of fuel supplied by the post injection, the temperature of the exhaust gas flowing into the exhaust treatment device, and the flow rate of the gas passing through the exhaust treatment device. 1 target value can be set.

More preferably, the exhaust treatment system further includes a notification device that notifies the user of predetermined information. The control device determines that the exhaust treatment device is in a deteriorated state when the first learned value exceeds the first threshold value. The control device determines that the fuel addition device is in a deteriorated state when the second learned value exceeds the second threshold value. The control device uses the notification device to notify the user of information based on the determination result.

In this manner, it is possible to determine with high accuracy whether the exhaust treatment device is in a deteriorated state using the first learned value, and to determine whether the fuel addition device is in a deteriorated state using the second learned value. It can be determined with high accuracy. Further, by informing the user of the information based on the determination result, the user can be made aware of the deterioration state of the exhaust treatment device or the fuel addition device.

According to the present invention, it is possible to provide an exhaust treatment system that accurately determines deterioration of an exhaust treatment device that purifies exhaust gas and deterioration of a fuel addition device that adds fuel to the exhaust treatment device.

It is a figure showing an example of a schematic structure of the engine in this embodiment. FIG. 5 is a diagram for explaining an example of temperature distribution in the exhaust treatment device when regeneration control is executed; FIG. 5 is a diagram for explaining an example of a temperature distribution in the exhaust treatment device when regeneration control is executed when the exhaust treatment device is deteriorated; FIG. 5 is a diagram for explaining an example of the temperature distribution in the exhaust treatment device 16 when regeneration control is executed when the fuel addition device has deteriorated; FIG. 4 is a diagram for explaining an example of a fuel injection mode during first injection control; FIG. FIG. 5 is a diagram for explaining an example of a fuel injection mode during second injection control; FIG. FIG. 5 is a diagram for explaining an example of a fuel injection mode during third injection control; FIG. FIG. 5 is a diagram for explaining temperature rise allowances of an oxidation catalyst corresponding to a plurality of injection modes; 4 is a flowchart showing an example of control processing executed by an ECU; FIG. 4 is a diagram for explaining an example of an operation of an ECU when post-injection is performed; FIG. It is a figure for demonstrating the amount of DOC deterioration, and the amount of filter deterioration. FIG. 4 is a diagram for explaining an example of an operation of an ECU when fuel addition is performed by a fuel addition device; It is a figure for demonstrating the calculation method of a 2nd learning value. FIG. 5 is a diagram showing an example of changes in the first learned value and the second learned value according to the running distance; It is a figure which shows an example of the map for calculating the target value of temperature rise allowance.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, identical parts are provided with identical reference numerals. Their names and functions are also the same. A detailed description thereof will therefore not be repeated.

FIG. 1 is a diagram showing an example of a schematic configuration of an engine 1 according to this embodiment. In the present embodiment, the engine 1 will be described as an example of a common rail diesel engine. However, the engine 1 may be any other type of diesel engine.

The engine 1 includes an engine body 10 , an exhaust manifold 12 , a supercharger 15 and an exhaust treatment system 200 .

The engine body 10 includes multiple cylinders (not shown), a common rail (not shown), and multiple injectors 11 . In the present embodiment, engine 1 is described as an example of an in-line four-cylinder engine, but it may be an engine with other cylinder layouts (for example, V-type or horizontal type).

A plurality of injectors 11 is a fuel injection device provided in each of a plurality of cylinders and each of which is connected to a common rail. The fuel stored in the fuel tank is pressurized to a predetermined pressure by the fuel pump and supplied to the common rail. The fuel supplied to the common rail is directly injected into the cylinder from each of the plurality of injectors 11 at a predetermined timing. The multiple injectors 11 operate based on control signals from the ECU 100 . ECU 100 controls a plurality of injectors 11, for example, so that multi-stage injection is performed. Multi-stage injection includes, for example, at least one of pilot injection, main injection, after-injection, and post-injection. Details of each of the plurality of injection modes will be described later.

Furthermore, each of the plurality of injectors 11 is provided with a pressure sensor, and the ECU 100 estimates the fuel injection amount from the plurality of injectors 11 with a certain degree of accuracy from changes in fuel pressure detected by each pressure sensor. ECU 100, for example, uses these estimation results to perform feedback control so that the actual injection amount and timing become the requested injection amount and timing.

The exhaust manifold 12 is connected to exhaust ports (not shown) of each of the plurality of cylinders of the engine body 10 . One end of an exhaust pipe 13 is connected to the exhaust manifold 12 . The other end of the exhaust pipe 13 is connected to the exhaust inlet of the turbocharger 15 . Therefore, the exhaust gas discharged from the exhaust port of each cylinder joins in the exhaust manifold 12 and is supplied to the turbine of the supercharger 15 via the exhaust pipe 13 .

Supercharger 15 includes a compressor and a turbine (both not shown). A compressor wheel is housed within the compressor housing and a turbine wheel is housed within the turbine housing. The compressor wheel and turbine wheel are connected by a connecting shaft and rotate integrally. Therefore, the compressor wheel is rotationally driven by the exhaust energy of the exhaust supplied from the exhaust pipe 13 to the turbine wheel. Air taken in from an intake pipe (not shown) is compressed by the rotation of the compressor wheel, and supplied to an intake manifold provided in the engine body 10 via a heat exchanger such as an intercooler. Air supplied to the intake manifold is supplied to each cylinder via an intake port formed in the engine body 10 .

Air supplied to each cylinder of the engine body 10 is mixed with fuel supplied from a plurality of injectors 11 to generate an air-fuel mixture. It is compressed by moving towards dead center. Combustion pressure is generated by compression ignition of the air-fuel mixture in the combustion chamber, pushing down the piston and rotating the crankshaft (output shaft) connected to the piston via a connecting rod. The exhaust discharged from the cylinder to the exhaust manifold 12 drives the supercharger 15 and is purified in the exhaust treatment system 200 .

An exhaust treatment system 200 in the present embodiment includes an exhaust treatment device 16 , a fuel addition device 14 and an ECU (Electronic Control Unit) 100 .

The exhaust treatment device 16 includes an oxidation catalyst (DOC: Diesel Oxidation Catalyst) 17 , a PM removal filter 18 , a first exhaust temperature sensor 102 , a second exhaust temperature sensor 104 and a third exhaust temperature sensor 106 .

The fuel addition device 14 is provided in the exhaust pipe 13 upstream of the oxidation catalyst 17 in the exhaust passage. The PM removal filter 18 is provided downstream of the oxidation catalyst 17 in the exhaust flow path (exhaust passage). The first exhaust temperature sensor 102 is provided in the exhaust flow path between the exhaust outlet of the turbine of the supercharger 15 and the oxidation catalyst 17 . The second exhaust temperature sensor 104 is provided in the exhaust flow path between the oxidation catalyst 17 and the PM removal filter 18 . The third exhaust temperature sensor 106 is provided in the exhaust flow path at the outlet on the downstream side of the PM removal filter 18 .

The PM removal filter 18 collects particulate matter (hereinafter referred to as PM (Particulate Matter)) contained in the flowing exhaust gas. The PM removal filter 18 is made of ceramic, stainless steel, or the like, for example. The collected PM deposits inside the PM removing filter 18 .

The fuel addition device 14 and the oxidation catalyst 17 function as a regeneration mechanism that burns and removes (regenerates) PM deposited on the PM removal filter 18 . The oxidation catalyst 17 oxidizes (purifies) nitrogen oxides (NOx), carbon oxides (COx), and the like in the flowing exhaust gas when the exhaust gas is circulating. Oxidize the fuel if the added fuel is included. The temperature of the exhaust gas passing through the oxidation catalyst 17 rises due to the heat of reaction generated by the oxidation of the fuel. As the high-temperature exhaust passes through the PM removal filter 18, the temperature of the PM removal filter 18 rises, and PM deposited in the PM removal filter 18 is oxidized and removed (burned). As a result, the PM removal filter 18 is regenerated.

An exhaust pipe (not shown) is connected to the rear end of the PM removal filter 18 of the exhaust treatment device 16, and an additional exhaust treatment device such as a catalyst for removing specific components from the exhaust gas, a muffler, and the like are connected to the exhaust pipe. be. Therefore, exhaust gas discharged from the turbine of the supercharger 15 is discharged outside the vehicle via the exhaust treatment device 16, various catalysts, a muffler, and the like.

Operation processing of the engine 1 and exhaust processing in the exhaust treatment device 16 are executed by the ECU 100 . ECU 100 includes a CPU (Central Processing Unit) that performs various processes, a memory including a ROM (Read Only Memory) that stores programs and data, a RAM (Random Access Memory) that stores CPU processing results, and the like. It is a control device including input/output ports (none of which are shown) for exchanging information with the outside.

Various sensors (eg, first exhaust temperature sensor 102, second exhaust temperature sensor 104, third exhaust temperature sensor 106, engine speed sensor 108, vehicle speed sensor 110, air flow meter 112, etc.) are connected to the input port of ECU 100. Connected.

Devices to be controlled (for example, multiple injectors 11, fuel addition device 14, warning light 114, etc.) are connected to the output port.

ECU 100 controls various devices so that engine 1 is in a desired operating state based on signals from sensors and devices, and maps and programs stored in memory. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuits). The ECU 100 also incorporates a timer circuit (not shown) for measuring time. The ECU 100 includes a first exhaust temperature sensor 102, a second exhaust temperature sensor 104, a third exhaust temperature sensor 106, an engine speed sensor 108, a vehicle speed sensor 110, an air flow meter 112, and a warning light 114. Connected.

The first exhaust temperature sensor 102 detects the temperature of the exhaust gas flowing into the exhaust treatment device 16 (more specifically, the oxidation catalyst 17) (hereinafter referred to as exhaust temperature Ta). The first exhaust temperature sensor 102 transmits a signal indicating the detected exhaust temperature Ta to the ECU 100 .

The second exhaust temperature sensor 104 detects the temperature of exhaust gas flowing out of the oxidation catalyst 17 (that is, flowing into the PM removal filter 18) (hereinafter referred to as exhaust temperature Tb). The second exhaust temperature sensor 104 transmits a signal indicating the detected exhaust temperature Tb to the ECU 100 .

The third exhaust temperature sensor 106 detects the temperature of exhaust gas flowing out from the exhaust treatment device 16 (more specifically, the PM removal filter 18) (hereinafter referred to as exhaust temperature Tc). Third exhaust temperature sensor 106 transmits a signal indicating detected exhaust temperature Tc to ECU 100 .

The exhaust temperatures Ta, Tb, and Tc may be obtained by estimating from the operating state of the engine 1 or from a temperature sensor provided at another location, instead of being directly detected by a temperature sensor provided near the oxidation catalyst 17 .

An engine rotation speed sensor 108 detects the rotation speed of the crankshaft of the engine 1 as an engine rotation speed NE. Engine speed sensor 108 transmits a signal indicating detected engine speed NE to ECU 100 .

Vehicle speed sensor 110 detects a vehicle speed (hereinafter referred to as vehicle speed) V. FIG. Vehicle speed sensor 110 transmits a signal indicating detected vehicle speed V to ECU 100 .

The air flow meter 112 detects the flow rate of air taken into the engine 1 (hereinafter referred to as the intake air amount) Q. The airflow meter 112 transmits a signal indicating the detected intake air amount Q to the ECU 100 .

Warning light 114 is provided, for example, at a position in the vehicle interior that is visible to the user, and notifies the user of the vehicle of predetermined information. Specifically, warning light 114 is configured to be capable of lighting an indicator light that issues a predetermined type of warning to the occupant in response to a control signal from ECU 100 . In the present embodiment, warning light 114 is, for example, an indicator light (maintenance lamp of exhaust treatment device 16) prompting replacement or maintenance due to deterioration of at least one of oxidation catalyst 17 and PM removal filter 18. ) and an indicator light (maintenance lamp of the fuel addition device 14) that prompts replacement or maintenance due to deterioration of the fuel addition device 14.

In the engine 1 configured as described above, when the amount of PM deposited in the PM removal filter 18 increases, the filter portion of the PM removal filter 18 may become clogged and its function may deteriorate. Therefore, the ECU 100 executes regeneration control for regenerating the PM removal filter 18 .

More specifically, the ECU 100 acquires the amount of PM accumulated in the PM removal filter 18 . The ECU 100 calculates, for example, an estimated value of PM emissions from a plurality of cylinders from the operating conditions of the engine 1 (eg, engine speed NE, fuel injection amount command value, intake air amount, etc.). The ECU 100 may acquire the accumulated amount by integrating the calculated estimated values. It should be noted that a well-known technique can be used for a specific method of calculating the emission amount of PM, and a detailed description thereof will not be given. The ECU 100 executes regeneration control when the acquired PM deposition amount exceeds the regeneration determination value.

The ECU 100 starts fuel addition from the fuel addition device 14 when the regeneration control is executed. The ECU 100 sets, for example, a command addition amount for increasing the exhaust temperature Tb to a target temperature, and controls the fuel addition device 14 according to the set command addition amount. Here, the target temperature of the exhaust gas is set as the exhaust gas temperature at which the temperature of the PM removal filter 18 can be raised to a temperature at which the PM removal filter 18 can be regenerated.

By the regeneration control as described above, in the exhaust treatment device 16, fuel is added to the exhaust by the fuel addition device 14, the added fuel reacts in the oxidation catalyst 17, and the reaction heat raises the temperature of the exhaust.

FIG. 2 is a diagram for explaining an example of the temperature distribution in the exhaust treatment device 16 during execution of regeneration control. The horizontal axis of FIG. 2 indicates the portion of the exhaust treatment device 16, and the further the direction of the arrow, the more downstream the portion of the exhaust. A portion indicated as “Before DOC” in FIG. 2 indicates the position where the first exhaust temperature sensor 102 detects the exhaust temperature. A portion indicated as “after DOC” in FIG. 2 indicates the position where the second exhaust temperature sensor 104 detects the exhaust temperature. 2 indicates the position where the third exhaust temperature sensor 106 detects the exhaust temperature. LN1 in FIG. 2 shows an example of the temperature distribution in the exhaust treatment device 16 when the regeneration control is not executed. LN2 in FIG. 2 shows an example of the temperature distribution in the exhaust treatment device 16 when regeneration control is executed.

When the regeneration control is not executed, fuel is not added from the fuel addition device 14, so as indicated by LN1 in FIG. 16, the temperature of the exhaust gas decreases due to heat radiation from the piping. Also, the temperature of the exhaust gas flowing into the exhaust treatment device 16 at this time is determined by the amount of heat generated by the combustion in the cylinder.

On the other hand, when the regeneration control is executed, the amount of fuel corresponding to the required calorific value is supplied from the fuel addition device 14, so the fuel is oxidized in the oxidation catalyst 17 as indicated by LN2 in FIG. The resulting heat of reaction raises the temperature. Hereinafter, the amount of increase in the exhaust gas temperature that occurs in the oxidation catalyst 17 will be referred to as the DOC temperature increase. Then, the temperature of the PM removal filter 18 further rises due to reaction heat generated in the same manner as the oxidation catalyst 17 . Hereinafter, the increase in exhaust gas temperature that occurs in the PM removal filter 18 will be referred to as filter temperature increase. As a result of the supply of fuel from the fuel addition device 14, the exhaust gas temperature rises by the sum of the DOC temperature rise amount and the filter temperature rise amount, resulting in the target temperature Tft(0). The total sum of the DOC temperature rise amount and the filter temperature rise amount corresponds to the temperature rise amount based on the required heat generation amount.

Then, as the high-temperature exhaust gas that has reached the target temperature as described above flows into the PM removal filter 18, the temperature of the PM removal filter 18 rises to a temperature within the temperature range in which regeneration of the PM removal filter 18 is possible. The temperature rises and the PM inside the PM removal filter 18 is burned. The ECU 100 counts the elapsed time in a state where the temperature of the PM removal filter 18 has reached a temperature within the temperature range in which regeneration of the PM removal filter 18 is possible, and the total counted elapsed time exceeds a predetermined regeneration end time. , it is determined that regeneration of the PM removal filter 18 has been completed.

In the exhaust treatment device 16 of the engine 1 configured as described above, if clogging occurs in the fuel addition device 14 or deterioration of the oxidation catalyst 17 or the PM removal filter 18 occurs, the PM removal filter 18 may not reach the target temperature. .

In the fuel addition device 14, deposits such as solidified fuel and soot may accumulate in the injection holes, causing clogging and deterioration. , there are cases where the amount of fuel that follows the addition command from the ECU 100 cannot be added.

In addition, in the oxidation catalyst 17 and the PM removal filter 18, the precious metal portion, which was uniformly distributed in the constituent members in the initial state, aggregates unevenly in one or a plurality of locations due to long-term use, and the reaction location with the fuel is reduced. Due to the decrease, the reaction heat equivalent to that in the initial state may not be generated.

Therefore, when the PM removal filter 18 cannot reach the target temperature, it is required to accurately determine whether the fuel addition device 14 is clogged and the exhaust treatment device 16 is deteriorated.

However, it may not be possible to determine with high accuracy whether the fuel addition device 14 or the exhaust treatment device 16 has deteriorated based only on the temperature of the exhaust gas flowing into the exhaust treatment device 16 or the temperature of the exhaust gas flowing out of the exhaust treatment device 16. be.

FIG. 3 is a diagram for explaining an example of the temperature distribution in the exhaust treatment device 16 during execution of regeneration control when the exhaust treatment device 16 has deteriorated. The horizontal axis in FIG. 3 indicates the portion of the exhaust treatment device 16 as in FIG. LN1 in FIG. 3 is similar to LN1 in FIG. Therefore, detailed description thereof will not be repeated. LN3 in FIG. 3 shows an example of the temperature distribution in the exhaust treatment device 16 when the exhaust treatment device 16 is deteriorated and regeneration control is executed. It is assumed that the fuel addition device 14 has not deteriorated.

When regeneration control is executed, fuel is supplied from the fuel addition device 14 in an amount corresponding to the required calorific value. As indicated by LN3, the DOC temperature increase and the filter temperature increase are reduced. Therefore, the temperature rise allowance corresponding to the required heat generation amount cannot be reached, and the exhaust gas temperature cannot be raised to Tft(0), which is the target temperature.

FIG. 4 is a diagram for explaining an example of the temperature distribution in the exhaust treatment device 16 during execution of regeneration control when the fuel addition device 14 has deteriorated. The horizontal axis in FIG. 4 indicates the portion of the exhaust treatment device 16 as in FIG. LN1 in FIG. 4 is similar to LN1 in FIG. Therefore, detailed description thereof will not be repeated. LN4 in FIG. 4 shows an example of the temperature distribution in the exhaust treatment device 16 when the fuel addition device 14 is deteriorated and regeneration control is executed. It is assumed that the exhaust treatment device 16 has not deteriorated.

When the regeneration control is executed, the fuel addition device 14 is instructed to supply the amount of fuel corresponding to the required heat generation amount to raise the temperature to the target temperature. However, if the injection holes of the fuel addition device 14 are clogged with deposits such as solidified fuel or soot, and the fuel addition device 14 deteriorates, the amount of fuel cannot be added according to the command.

Therefore, the amount of heat generated by the actually added fuel is smaller than the required amount of heat generated to raise the temperature to the target temperature. As a result, even if the exhaust temperature rises due to the fuel supplied to the oxidation catalyst 17 and the PM removal filter 18, the exhaust temperature cannot be raised to the target temperature Tft(0).

Thus, when the exhaust temperature does not rise, both of the fuel addition device 14 and the exhaust treatment device 16 may have deteriorated. Therefore, deterioration of the fuel addition device 14 and deterioration of the exhaust treatment device 16 cannot be determined with high accuracy based only on the exhaust temperature, and further improvement in determination accuracy is required.

Therefore, in the present embodiment, the ECU 100 operates as follows. That is, the ECU 100 sets the target value using a predetermined relationship between the operating state of the engine 1 and the target value of the temperature increase of the exhaust treatment device 16 corresponding to the operating state and the operating state. The ECU 100 obtains a first measured value of the temperature rise of the exhaust treatment device 16 by post-injection using the injector 11, and a target value of the temperature rise corresponding to the operating state of the engine 1 when the first measured value is detected. A first learning value indicating the degree of deterioration of the exhaust treatment device 16 is calculated by using the difference between . Further, the ECU 100 uses the second actual measurement value of the temperature rise amount of the exhaust treatment device 16 due to the addition of fuel using the fuel addition device 14, the above-described target value, and the above-described first learning value to determine the fuel addition device A second learning value indicating the degree of deterioration of 14 is calculated.

By doing so, the first learned value indicating the degree of deterioration of the exhaust treatment device 16 can be calculated with high accuracy by performing the post-injection (that is, without using the fuel addition device 14). Furthermore, by using the calculated first learned value, the second learned value indicating the degree of deterioration of the fuel addition device 14 can be calculated with high accuracy. Therefore, deterioration of the exhaust treatment device 16 and deterioration of the fuel addition device 14 can be determined with high accuracy.

The temperature rise of the exhaust treatment device 16 using the injector 11 will be described below with reference to FIGS. 5, 6 and 7. FIG.

The ECU 100 changes the injection control for injecting fuel from the injector 11 to the first injection control that does not involve an increase in the temperature of the exhaust treatment device, the second injection control that delays the injection timing more than the first injection control, and the second injection control. The temperature of the exhaust treatment device 16 can be raised by executing the third injection control in which the post-injection is performed.

FIG. 5 is a diagram for explaining an example of a fuel injection mode during the first injection control. The horizontal axis of FIG. 5 indicates the crank angle. FIG. 5 shows the injection timing during execution of the first injection control set with reference to TDC (Top Dead Center).

Pilot injection, main injection, and after injection are performed in the first injection control. The pilot injection is an injection mode in which a small amount of fuel is injected before the main injection, and the small amount of fuel injected burns to increase the temperature in the combustion chamber and reduce the ignition delay of the fuel in the main injection. and reduce noise.

The main injection is an injection mode in which an amount of fuel capable of generating a required output (for example, set based on the accelerator opening) is injected. This is an injection mode in which the injection amount of fuel is large compared to the post-injection and post-injection.

After-injection is an injection mode in which a small amount of fuel is injected after main injection. It is an injection mode that suppresses the occurrence.

As shown in FIG. 5, two pilot injections are performed at predetermined intervals, starting at a crank angle that is a predetermined crank angle before TDC. Note that the number of pilot injections is not particularly limited to two. The injection amount of fuel in the pilot injection is determined in advance by the ECU 100 based on the operating state of the engine 1 .

The main injection is performed immediately before TDC after the first period has elapsed since the second pilot injection was performed. The after-injection is performed once after the second period has elapsed since the main injection was performed. The number of times of main injection and after-injection is not particularly limited to one.

FIG. 6 is a diagram for explaining an example of a fuel injection mode during the second injection control. The horizontal axis in FIG. 6 indicates the crank angle. FIG. 6 shows the injection timing during execution of the second injection control set with reference to TDC. Pilot injection, main injection, and after injection are performed in the second injection control. The second injection control differs from the above-described first injection control in that the injection timings of the pilot injection, the main injection, and the after injection are each retarded by a predetermined crank angle.

As shown in FIG. 6, two pilot injections are performed at predetermined intervals starting from the crank angle immediately before TDC. The interval between two pilot injections is the same as the interval between two pilot injections in the first injection control.

The main injection is performed at a timing after the first period has elapsed since the second pilot injection was performed. The after-injection is performed after the second period has elapsed since the main injection was performed.

FIG. 7 is a diagram for explaining an example of a fuel injection mode during the third injection control. The horizontal axis in FIG. 7 indicates the crank angle. FIG. 7 shows the injection timing during execution of the third injection control set with reference to TDC. Pilot injection, main injection, after injection, and post injection are performed in the third injection control. The third injection control differs from the second injection control in that post-injection is performed.

Post-injection is an injection mode for the purpose of supplying fuel for raising the temperature of the exhaust treatment device 16 at a timing unrelated to the output of the engine 1 . Post-injection is performed twice in the third injection control. The total amount of two post-injections corresponds to the amount of fuel that raises the exhaust treatment device 16 to the target temperature. Note that the number of post injections is not particularly limited to two. Further, the amount of fuel that raises the temperature of the exhaust treatment device 16 to the target temperature may be injected in the post-injection using multiple cycles or multiple injectors 11 .

As shown in FIG. 7, two pilot injections are performed at predetermined intervals starting from the crank angle immediately before TDC. The interval of the second pilot injection is the same as the interval of two pilot injections in the first injection control and the second injection control.

The main injection is performed at a timing after the first period has elapsed since the second pilot injection was performed. The after-injection is performed after the second period has elapsed since the main injection was performed. Then, the post-injection is performed twice, starting from the crank angle after the third period has elapsed since the after-injection was performed.

The second injection control and the third injection control can raise the temperature of the exhaust gas and the temperature of the oxidation catalyst 17 compared to the first injection control.

FIG. 8 is a diagram for explaining the temperature rise allowance of the oxidation catalyst 17 corresponding to each of a plurality of injection modes. The vertical axis in FIG. 8 indicates the temperature of the oxidation catalyst 17 . As shown in FIG. 8, when the second injection control is executed, the amount of heat in the exhaust gas in the cylinder increases due to the retardation of the injection timing compared to when the first injection control is executed. As the exhaust heat from the cylinder increases, part of the unburned fuel is oxidized in the oxidation catalyst 17 to generate reaction heat. As a result, the temperature of the oxidation catalyst 17 (catalyst bed temperature) increases more than when the first injection control is executed. Furthermore, when the third injection control is executed, post-injection is executed compared to when the second injection control is executed. In addition to this, an increase in the amount of unburned fuel supplied to the oxidation catalyst 17 generates a large amount of heat of reaction. As a result, the catalyst bed temperature of the oxidation catalyst 17 increases more than when the second injection control is executed.

Such post-injection may dilute the engine oil if it is used frequently, so although the number of times is limited, it is possible to increase the temperature of the exhaust gas in the same manner as the fuel addition device 14, and the exhaust treatment device 16 is able to The amount of fuel to be supplied can be estimated with high accuracy. Therefore, by executing the post-injection, the temperature change of the exhaust treatment device 16 is actually measured, and the difference between the measured value and the target value is used as the first learned value to determine whether the exhaust treatment device 16 is in a deteriorated state. It can be determined with high accuracy. Also, by actually measuring the temperature change of the exhaust treatment device 16 due to fuel addition by the fuel addition device 14 and calculating the second learned value using the measured value, the first learned value, and the target value, the fuel addition device 14 It is possible to accurately determine whether or not the vehicle is in a deteriorated state.

Control processing executed by ECU 100 in the present embodiment will be described below with reference to FIG. FIG. 9 is a flowchart showing an example of control processing executed by the ECU 100. As shown in FIG. The processing shown in this flowchart is called and executed from a main routine (not shown) at each predetermined control cycle.

At step (hereinafter, step is referred to as S) 100, ECU 100 determines whether or not a learning condition is satisfied. The learning conditions are, for example, a first condition that the feedback control of the injection amount of the injector 11 is completed, a second condition that the vehicle speed V is maintained at a predetermined vehicle speed for a predetermined period or longer, and various sensors. and a third condition of indicating a normal value. For example, the ECU 100 determines that the feedback control of the injector 11 is completed when the difference between the actual fuel injection amount and the command injection amount of the injector 11 becomes equal to or less than a threshold value, and sets the completion flag to the ON state. . ECU 100 determines that the first condition is satisfied, for example, when the completion flag is on. Further, the ECU 100 determines that the second condition is established when the vehicle speed V detected by the vehicle speed sensor 110 is within a predetermined range including a predetermined vehicle speed and is maintained for a predetermined period of time or longer. do. Further, the ECU 100 determines that the third condition is satisfied when the output values of the various sensors are within the range of values output during normal operation. ECU 100 determines that the learning condition is satisfied, for example, when it is determined that all of the first condition, the second condition, and the third condition are satisfied. If it is determined that the learning condition is satisfied (YES at S100), the process proceeds to S102.

In S102, the ECU 100 sets a target value for a temperature increase in the oxidation catalyst 17 (hereinafter referred to as a DOC temperature increase) and a temperature increase in the PM removal filter 18 (hereinafter referred to as a filter temperature increase). Set target values. The ECU 100 sets the target value of the DOC temperature increase and the target value of the filter temperature increase using, for example, the operating state of the engine 1 and a predetermined relationship between the operating state and the target value.

More specifically, the ECU 100 determines the target value of the DOC temperature increase using a map showing the relationship between the post injection amount, the exhaust gas temperature Ta, the amount of gas passing through the exhaust treatment device 16, and the DOC temperature increase. set. For example, a map showing the relationship between the exhaust gas temperature Ta, the gas amount, and the target value of the DOC temperature rise allowance is set for each post injection amount. It should be noted that the fuel injection amount in the post-injection is determined by the operating state of the engine 1 .

For example, the ECU 100 selects an appropriate map based on the post-injection amount, and sets a target value for the DOC temperature increase from the exhaust temperature Ta, the gas amount, and the selected map. A map for setting the target value of the DOC temperature rise allowance is adapted through experiments or the like and stored in the memory of the ECU 100 in advance.

The ECU 100 estimates the amount of gas in the exhaust treatment device 16 by using history information of the intake air amount Q, for example. ECU 100 estimates the current amount of gas, for example, based on the amount of intake air before the current time when the air contained in the gas that has passed through exhaust treatment device 16 circulated through the intake passage.

Furthermore, the ECU 100 sets a target value for the filter temperature increase using a map showing the relationship between the post injection amount, the exhaust temperature Ta, the amount of gas passing through the exhaust treatment device 16, and the filter temperature increase. Since the map is the same as the map for setting the target value of the DOC temperature increase described above, detailed description thereof will not be repeated. For example, the ECU 100 selects an appropriate map based on the post-injection amount, and sets the target value of the filter temperature increase from the exhaust temperature Ta and gas amount selection and the selected map. A map for setting the target value of the filter temperature increase is adapted through experiments or the like and stored in the memory of the ECU 100 .

In S104, ECU 100 executes third injection control including post injection. Since the third injection control is as described above, detailed description thereof will not be repeated.

In S106, ECU 100 calculates the amount of DOC deterioration. Specifically, the ECU 100 calculates a value obtained by subtracting the measured value of the DOC temperature increase amount from the target value of the DOC temperature increase amount as the DOC deterioration amount. The ECU 100 may calculate, for example, a value obtained by subtracting the exhaust temperature Ta from the exhaust temperature Tb as the actual measurement value of the DOC temperature increase, or calculate the exhaust temperature when the oxidation catalyst 17 does not supply fuel from the exhaust temperature Ta. may be subtracted from the exhaust temperature Tb to calculate the actually measured value of the first temperature increase.

In S108, ECU 100 calculates the filter deterioration amount. Specifically, the ECU 100 calculates, as the filter deterioration amount, a value obtained by subtracting the actually measured value of the filter temperature increase from the target value of the filter temperature increase. The ECU 100 acquires, for example, a value obtained by subtracting the exhaust temperature Tb from the exhaust temperature Tc as the actual measurement value of the filter temperature increase.

In S110, ECU 100 calculates a first learned value. ECU 100 calculates the first learning value using, for example, the DOC deterioration amount and the filter deterioration amount. The ECU 100 calculates, for example, the ratio of the sum of the DOC deterioration amount and the filter deterioration amount to the sum of the target value of the DOC temperature increase amount and the target value of the filter temperature increase amount as the first learning value. ECU 100, for example, first learns the larger of the ratio of the DOC deterioration amount to the target value of the DOC temperature increase and the ratio of the filter deterioration amount to the target value of the filter temperature increase. It may be calculated as a value. The first learning value may be expressed as a percentage, for example.

At S112, the ECU 100 determines whether or not the exhaust temperature is constant. For example, the ECU 100 may determine that the exhaust gas temperature is in a constant state when a predetermined period of time has elapsed since execution of the third injection control, or may determine that the amount of time change in the exhaust temperature Tb or Tc is large. It may be determined that the exhaust temperature is constant when the difference between the exhaust temperatures Ta and Tc is equal to or less than the threshold. You can judge. If it is determined that the exhaust temperature is constant (YES at S112), the process proceeds to S114. If it is determined that the exhaust temperature is not constant (NO in S112), the process returns to S112.

In S114, ECU 100 performs fuel addition using fuel addition device . The ECU 100 controls the fuel addition device 14, for example, so that an amount of fuel corresponding to the amount of fuel supplied by post-injection is added. The ECU 100 may, for example, estimate the amount of fuel supplied by the post-injection and output a fuel addition command to the fuel addition device 14 so that the estimated amount of fuel is added.

In S116, ECU 100 calculates a second learning value. For example, the ECU 100 calculates the sum of the target value of the DOC temperature increase and the target value of the filter temperature increase. The ECU 100 calculates the measured value of the DOC temperature increase, the measured value of the filter temperature increase, and the temperature decrease corresponding to the first learned value (that is, the sum of the DOC deterioration amount and the filter deterioration amount) from the calculated sum. Calculate the temperature deficit by subtracting. The ECU 100 calculates, as a second learning value, the ratio of the shortfall to the sum of the target value of the DOC temperature increase and the target value of the filter temperature increase. The second learning value may be indicated, for example, as a percentage.

In S118, ECU 100 determines whether or not the first learned value is greater than or equal to threshold value Th(0). The threshold Th(0) is a predetermined value and is adapted by experiment or the like. If it is determined that the first learned value is greater than or equal to threshold Th(0) (YES at S118), the process proceeds to S120.

In S120, ECU 100 controls warning light 114 so that the maintenance lamp of exhaust treatment device 16 is turned on. If the first learned value is smaller than threshold Th(0) (NO in S118), the process proceeds to S122.

In S122, ECU 100 determines whether or not the second learned value is greater than or equal to threshold Th(0). If it is determined that the second learned value is equal to or greater than threshold Th(0) (YES at S122), the process proceeds to S124.

In S124, ECU 100 controls warning light 114 so that the maintenance lamp of fuel addition device 14 is lit. If the learning condition is not satisfied (NO at S100) or if it is determined that the second learned value is smaller than the threshold value Th(0) (NO at S122), this process is terminated.

The operation of the ECU 100 based on the structure and flow charts described above will be described with reference to FIGS. 10 to 14. FIG.

For example, when the feedback control of the injector 11 is completed, the vehicle speed V is maintained within a predetermined range, and the output values of various sensors are within the normal range (in S100 YES), the target value of the DOC temperature increase and the target value of the filter temperature increase are set (S102). Then, by executing the third injection control (S104), the temperature of the exhaust treatment device 16 is raised by the post-injection.

FIG. 10 is a diagram for explaining an example of the operation of the ECU 100 when post-injection is performed. The horizontal axis of FIG. 10 indicates the portion of the exhaust treatment device 16 . LN5 (broken line) in FIG. 10 indicates that the post-injection amount of fuel that raises the exhaust temperature to the target temperature Tft(0) when the oxidation catalyst 17 and the PM removal filter 18 are in the initial state (new state) where the oxidation catalyst 17 and the PM removal filter 18 are not deteriorated. 1 shows an example of the temperature distribution in the exhaust treatment device 16 when supplied by . LN5 (thick solid line) in FIG. 10 shows an example of the actual temperature distribution in the exhaust treatment device 16 after post-injection. LN6 (thin solid line) in FIG. 10 shows an example of the temperature distribution in the exhaust treatment device 16 when fuel is not supplied to the exhaust treatment device 16. FIG.

At this time, the exhaust temperature Ta before DOC, the exhaust temperature Tb after DOC, and the exhaust temperature Tc after filtering are detected by the first exhaust temperature sensor 102, the second exhaust temperature sensor 104, and the third exhaust temperature sensor 106. be. As a result, the value corresponding to the height of the position before DOC, the value corresponding to the height of the position after DOC, and the value corresponding to the height of the position after filtering in LN6 in FIG. is obtained. From these acquired values, the measured value of the DOC temperature increase and the measured value of the filter temperature increase are calculated.

Here, the value corresponding to the difference between the value corresponding to the height of LN5 in FIG. 10 and the value corresponding to the height of LN7 in FIG. It will be set as a target value. Further, from the operating state of the engine 1, from the value corresponding to the height of LN5 in FIG. 10 at the position after the filter, the value corresponding to the height of LN7 in FIG. is set as the target value of the filter temperature increase.

FIG. 11 is a diagram for explaining the amount of DOC deterioration and the amount of filter deterioration. The vertical axis in FIG. 11 indicates the catalyst bed temperature. The left side of FIG. 11 shows the target value and actual measurement value of the DOC temperature rise allowance of the oxidation catalyst 17 . The right side of FIG. 11 shows the target value and actual measurement value of the filter temperature rise allowance of the PM removal filter 18 .

As shown in FIG. 11, the DOC deterioration amount is calculated by subtracting the measured value of the DOC temperature increase from the target value of the DOC temperature increase (S106). Further, the amount of filter deterioration is calculated by subtracting the measured value of the filter temperature increase from the target value of the filter temperature increase (S108). Then, the ratio of the sum of the DOC deterioration amount and the filter deterioration amount to the sum of the target value of the DOC temperature increase amount and the target value of the filter temperature increase amount is calculated as a first learning value (S110).

After that, when the exhaust temperature reaches a constant state (YES in S112), fuel is added by the fuel addition device 14 (S114). At this time, the fuel addition device 14 is controlled so that an amount of fuel corresponding to the amount of fuel supplied by the post-injection is supplied.

FIG. 12 is a diagram for explaining the operation of the ECU 100 when the fuel addition device 14 performs fuel addition. The horizontal axis of FIG. 12 indicates the portion of the exhaust treatment device 16 . LN5 and LN7 in FIG. 12 are similar to LN5 and LN7 in FIG. Therefore, detailed description thereof will not be repeated. LN8 (thick solid line) in FIG. 12 shows an example of the actual temperature distribution in the exhaust treatment device 16 after fuel is added by the fuel addition device 14 .

At this time, the exhaust temperature Ta before DOC, the exhaust temperature Tb after DOC, and the exhaust temperature Tc after filtering are detected by the first exhaust temperature sensor 102, the second exhaust temperature sensor 104, and the third exhaust temperature sensor 106. be. As a result, the value corresponding to the height of the position before DOC, the value corresponding to the height of the position after DOC, and the value corresponding to the height of the position after filtering in LN8 in FIG. is obtained. From these acquired values, the measured value of the DOC temperature increase and the measured value of the filter temperature increase are calculated.

Here, at the post-DOC position, the target value of the DOC temperature increase is indicated by the difference between the value corresponding to the height of LN5 in FIG. 12 and the value corresponding to the height of LN7 in FIG. A value obtained by subtracting the actual measured value of the DOC temperature increase and the amount of DOC deterioration from the target value of the DOC temperature increase corresponds to the insufficient portion of the oxidation catalyst 17 due to the deterioration of the fuel addition device 14 . Similarly, at the post-filter position, the difference between the value corresponding to the height of LN5 in FIG. 12 and the value corresponding to the height of LN7 in FIG. It is indicated as the target value of the temperature allowance. A value obtained by subtracting the actual filter temperature rise value and the amount of deterioration of the filter from the target value of the filter temperature rise corresponds to the insufficient portion of the PM removal filter due to the deterioration of the fuel addition device 14 .

FIG. 13 is a diagram for explaining a method of calculating the second learning value. The vertical axis in FIG. 12 indicates temperature. The left side of FIG. 13 shows the target value, actual measurement value, and DOC deterioration amount of the DOC temperature increase of the oxidation catalyst 17 . The right side of FIG. 13 shows the target value, actual measurement value, and amount of deterioration of the filter temperature increase for the PM removal filter 18 .

As shown in FIG. 13, from the sum of the target value of the DOC temperature rise and the target value of the filter temperature rise, the measured value of the DOC temperature rise, the amount of DOC deterioration, the measured value of the filter temperature rise, and the filter The value obtained by subtracting the amount of deterioration (the value corresponding to the frame of the dashed line in FIG. 13) is calculated as the insufficient portion. Then, the ratio of the insufficient part to the sum of the target value of the DOC temperature increase and the target value of the filter temperature increase is calculated as a second learning value (S116).

It is determined whether or not the first learned value is equal to or greater than threshold Th(0) (S118). 2 It is determined whether or not the learned value is greater than or equal to the threshold Th(0) (S122).

FIG. 14 is a diagram showing an example of changes in the first learned value and the second learned value according to the mileage. The vertical axis in FIG. 14 indicates the learning value. The horizontal axis of FIG. 14 indicates the running distance. LN9 in FIG. 14 shows an example of change in the first learned value. LN10 in FIG. 14 shows an example of a change in the second learned value.

As shown in FIG. 14, the first learned value and the second learned value increase as the travel distance increases. For example, when the first learned value increases by a larger amount in the predetermined period than the second learned value, the first learned value is set to the threshold value Th ( 0) is reached. When the first learned value becomes equal to or greater than threshold Th(0) (YES in S118), the maintenance lamp of exhaust treatment device 16 is lit (S120).

After that, when the vehicle continues to run after the exhaust treatment device 16 is replaced, etc., if the second learned value becomes equal to or greater than the threshold value Th(0) at the traveled distance L(1) (YES in S122 ), the maintenance lamp of the fuel addition device 14 is lit (S124).

As described above, according to the exhaust treatment system according to the present embodiment, the first learned value indicating the degree of deterioration of the exhaust treatment device 16 is obtained by performing the post-injection (that is, without using the fuel addition device 14). It can be calculated with high accuracy. Furthermore, by using the calculated first learned value, the second learned value indicating the degree of deterioration of the fuel addition device 14 can be calculated with high accuracy. In particular, even when the exhaust treatment device 16 includes the oxidation catalyst 17 and the PM removal filter 18, the first learned value can be calculated with high accuracy using the DOC deterioration amount and the filter deterioration amount. Therefore, it is possible to provide an exhaust treatment system that accurately determines the deterioration of the exhaust treatment device 16 and the deterioration of the fuel addition device 14 .

Furthermore, the target value of the DOC temperature increase and the target value of the filter temperature increase are set to the amount of fuel supplied by post injection, the temperature of the exhaust gas flowing into the exhaust treatment device 16, and the amount of gas passing through the exhaust treatment device 16. By using the map showing the relationship with the flow rate, it is possible to appropriately set the target value of the temperature increase corresponding to the operating state of the engine 1 .

Furthermore, the first learned value can be used to accurately determine whether the exhaust treatment device 16 is in a deteriorated state, and the second learned value can be used to accurately determine whether the fuel addition device 14 is in a deteriorated state. high can be determined. Further, by informing the user of the information based on the determination result, the user can be made aware of the deterioration state of the exhaust treatment device 16 or the fuel addition device 14 . Therefore, erroneous replacement of normal components can be suppressed.

Modifications will be described below.
In the above-described embodiment, the first learning value is calculated using the DOC deterioration amount and the filter deterioration amount, and when the calculated first learning value is equal to or greater than the threshold value Th(0), the exhaust treatment device 16 maintenance lamp is turned on, but the ratio of the DOC deterioration amount to the target value of the DOC temperature increase and the ratio of the filter deterioration amount to the target value of the filter temperature increase are calculated as learning values. , determines whether or not each learned value is equal to or greater than the threshold value Th(0), and if any learned value is equal to or greater than the threshold value Th(0), the maintenance lamp of the exhaust treatment device 16 is turned on. You may make it light.

Further, in the above-described embodiment, the ratio of the sum of the DOC deterioration amount and the filter deterioration amount to the total sum of the target value of the DOC temperature increase amount and the target value of the filter temperature increase amount is calculated as the first learning value. However, the sum of the DOC deterioration amount and the filter deterioration amount may be calculated as the first learning value. In this case, the above-mentioned insufficient portion due to fuel addition using the fuel addition device 14 is calculated as the second learning value.

Furthermore, in the above-described embodiment, the maintenance lamp of the exhaust treatment device 16 is lit when the first learned value is equal to or greater than the threshold Th(0), and the first learned value is greater than the threshold Th(0). Although the maintenance lamp of the fuel addition device 14 is lit when the second learning value is smaller and the second learning value is equal to or greater than the threshold value Th(0), it is assumed that the maintenance lamp of the fuel addition device 14 is turned on. The amount of fuel added from the fuel addition device 14 may be corrected to increase by the value. In this way, the temperatures of the oxidation catalyst 17 and the PM removal filter 18 can be raised to within the regenerative temperature range, so regeneration of the PM removal filter 18 can be performed appropriately. The increase correction may be performed by feeding back the difference from the actual measurement value so that the temperature increase becomes the target value, or by multiplying the amount by a predetermined amount or a predetermined coefficient. It may be done in this way.

Furthermore, in the above-described embodiment, the maintenance lamp of the exhaust treatment device 16 is turned on when the first learned value is equal to or greater than the threshold Th(0), and when the second learned value is equal to or greater than the threshold Th(0). The explanation has been given assuming that the maintenance lamp of the fuel addition device 14 is turned on in one case. However, if any of the integrated values exceeds the threshold, the maintenance lamp of the device corresponding to the integrated value exceeding the threshold may be turned on.

Furthermore, in the above-described embodiment, it is determined whether or not the second learned value is equal to or greater than the threshold Th(0) when the first learned value is not equal to or greater than the threshold Th(0). , determines whether the second learned value is equal to or greater than the threshold Th(0), and if the second learned value is not equal to or greater than the threshold Th(0), the first learned value is equal to the threshold Th(0). ) or more.

Furthermore, in the above-described embodiment, it is determined whether or not the second learned value is equal to or greater than the threshold Th(0) when the first learned value is not equal to or greater than the threshold Th(0). , the threshold for the first learned value and the threshold for the second learned value may be the same value or may be different values.

Furthermore, in the above-described embodiment, the fuel addition device 14 was described as being provided in the exhaust pipe 13, but it may be provided at least upstream of the exhaust treatment device 16, for example, from the turbine of the supercharger 15. It may be provided at a downstream exhaust pipe position.

Furthermore, in the above-described embodiment, as shown in FIG. 15, a map for calculating the target value of the temperature rise margin shows the relationship between the temperature of the exhaust gas flowing into the exhaust treatment device 16, the flow rate of the passing gas, and the target value. Although the map is set for each post-injection amount, a three-dimensional map showing the relationship between the temperature of the exhaust gas flowing into the exhaust treatment device 16, the flow rate of the passing gas, the post-injection amount, and the target value may be used. Alternatively, it may be set using a formula, a function, or the like.

Furthermore, in the above-described embodiment, the first learning value is calculated using the DOC deterioration amount of the oxidation catalyst 17, which is an exhaust treatment device, and the filter deterioration amount of the PM removal filter 18, which is an exhaust treatment device. However, either one of the DOC deterioration amount and the filter deterioration amount may be used to calculate the first learning value. That is, the deterioration amount may be calculated for the oxidation catalyst 17 or the PM removal filter 18 .

In addition, you may implement the above-described modification combining all or one part.
It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

1 engine, 10 engine body, 11 injector, 12 exhaust manifold, 13 exhaust pipe, 14 fuel addition device, 15 supercharger, 16 exhaust treatment device, 17 oxidation catalyst, 18 PM removal filter, 100 ECU, 102 first exhaust temperature Sensor, 104 second exhaust temperature sensor, 106 third exhaust temperature sensor, 108 engine speed sensor, 110 vehicle speed sensor, 112 air flow meter, 114 warning light, 200 exhaust treatment system.

Claims (4)

An exhaust treatment system for purifying exhaust from an engine having a cylinder,
an exhaust treatment device that is provided in an exhaust passage of the engine and raises temperature by heat of reaction with fuel in the exhaust;
a first detection device for detecting a first temperature of exhaust gas flowing into the exhaust treatment device;
a second detection device that detects a second temperature of the exhaust gas flowing out of the exhaust treatment device;
a fuel addition device provided upstream of the exhaust treatment device in the exhaust passage and adding fuel to the exhaust passage;
a fuel supply device that supplies fuel to the inside of the cylinder;
a control device that controls the fuel addition device and the fuel supply device using a first temperature increase indicated by the difference between the first temperature and the second temperature;
The control device is
setting the first target value using a predetermined relationship between the operating state of the engine and a first target value of the first temperature rise allowance corresponding to the operating state and the operating state;
Using the difference between the first measured value of the first temperature increase due to post-injection using the fuel supply device and the first target value corresponding to the operating state when the first measured value is detected calculating a first learned value indicating the degree of deterioration of the exhaust treatment device;
The degree of deterioration of the fuel addition device is indicated by using the second measured value of the first temperature increase due to addition of fuel using the fuel addition device, the first target value, and the first learned value. An exhaust treatment system that calculates a second learning value. The exhaust treatment device is an oxidation catalyst,
The exhaust treatment system is provided at a position downstream of the oxidation catalyst and collects particulate matter contained in the exhaust gas flowing through the exhaust passage;
a third detection device that detects a third temperature of the exhaust gas flowing out of the filter;
The control device is
setting the first target value and the second target value of the second temperature increase indicated by the difference between the second temperature and the third temperature, corresponding to the operating state;
Using the difference between the first measured value and the first target value obtained by the post-injection and the difference between the third measured value of the second temperature increase due to the post-injection and the second target value, Calculate the first learning value,
the second measured value, the fourth measured value of the second temperature increase due to addition of fuel using the fuel addition device, the first target value, the second target value, and the first learned value 2. The exhaust treatment system according to claim 1, wherein the second learning value is calculated using and. The control device determines the operating state using a predetermined relationship among the amount of fuel supplied by the post injection, the temperature of the exhaust gas flowing into the exhaust treatment device, and the flow rate of gas passing through the exhaust treatment device. 3. The exhaust treatment system according to claim 1, wherein the corresponding first target value is set. The exhaust treatment system further includes a notification device that notifies the user of predetermined information,
The control device determines that the exhaust treatment device is in a deteriorated state when the first learned value exceeds a first threshold, and determines that the second learned value exceeds a second threshold, 4. The exhaust treatment system according to any one of claims 1 to 3, wherein said fuel addition device is determined to be in a deteriorated state, and information based on the determination result is reported to said user using said notification device.

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