JP5859501B2 - Engine exhaust purification device and method - Google Patents

Description

  The present invention relates to an exhaust purification apparatus and method for an engine having a filter that is provided in an exhaust passage of an engine and that collects particulates in exhaust gas and performs forced regeneration to remove the collected particulates by heating to remove fuel. Is.

  As an exhaust gas purification device that purifies exhaust gas from a diesel engine, an exhaust gas purification device that uses a DPF (Diesel Particulate Filter) is known. In such an exhaust purification device using DPF, soot that is particulates (PM) in exhaust gas is collected and discharged by DPF.

  The DPF has a limit in the amount of collected soot. Therefore, in order to prevent the so-called “over-deposited state” from being accumulated too much in the DPF, an engine control unit (Engine Control Unit: ECU) is automatically activated when the so-called “over-deposited state” is accumulated in the DPF. Automatic playback (playback during operation) or manual playback in which the user notifies the playback timing by means of lamp lighting / flashing, etc. and the user performs playback by operating the switch, etc. are generally implemented. .

  However, even if the above-mentioned means such as automatic regeneration and manual regeneration are taken, an over-deposition state may occur, and in the case of an over-deposition state, the limp home mode is entered, and the engine output is reduced and the regeneration is prohibited. . In such a case, to release this state, bring the vehicle equipped with the engine to a service base such as a dealer or repair shop, and remove the DPF that has been over-deposited at the service base. At present, the over-deposition state is released by cleaning or replacement.

  However, when the DPF is over-deposited, it is possible to easily move and transport the vehicle to the service base in the case of an on-road vehicle, but to the service base in the case of an off-road vehicle. It is not easy to move and carry vehicles. This is because there are restrictions on the number of service bases, places of use, and movement methods.

  Therefore, as a technique related to the regeneration of the DPF, Patent Documents 1 and 2 disclose a technique for determining the regeneration temperature and the regeneration time in accordance with the PM deposition amount of the DPF.

  In addition, as a technique for dealing with the case where the DPF is over-deposited, Patent Document 3 discloses that when the DPF is over-deposited and enters the limp home mode, PM (Particulate Matter) is not increased. A technique for controlling an operation method so that a necessary torque can be output is disclosed.

  Further, as a technique that can regenerate the DPF even when the DPF is over-deposited, Patent Document 4 discloses that when the DPF is over-deposited, the electric heating means and the air supply means are controlled. A technique for regenerating DPF by incinerating PM deposited on DPF is disclosed.

Japanese Patent No. 4008867 JP 2007-239740 A JP 2007-218196 A JP 2000-38917 A

  However, the techniques disclosed in Patent Document 1 and Patent Document 2 are not related to the overdeposition state, and the DPF cannot be regenerated in the overdeposition state.

  In addition, the technique disclosed in Patent Document 3 can generate a necessary torque without increasing PM in the case of an overdeposition state, but cannot release the overdeposition state.

  In addition, the technique disclosed in Patent Document 4 needs to newly provide an electric heating means such as an electric heating device, increase in manufacturing cost due to an increase in the number of parts, limitation of placement location, expression of possibility of new failure, etc. The problem remains.

  In order to solve the above-described problems, in the present invention, in an exhaust purification device for an engine having a filter that is provided in an exhaust passage of an engine and collects particulates in exhaust gas, the soot collected by the filter is accumulated more than a predetermined amount. It is an object of the present invention to provide an engine exhaust purification device and method capable of regenerating the filter without adding new parts even in an “overdeposited state”. It is another object of the present invention to provide a filter regeneration system according to the engine exhaust gas purification apparatus.

  As an invention relating to an exhaust emission control device for an engine for solving the above problems, in the present invention, in the exhaust passage of the engine, particulates in the exhaust gas are collected, and the collected particulates are removed by heating. A filter that performs forced regeneration, an oxidation catalyst that is disposed upstream of the filter and raises the temperature of the filter, and regeneration control that regenerates the filter by regenerating the particulates deposited on the filter And the control means collects the fine particles on the filter when the amount of fine particles accumulated on the filter exceeds a predetermined amount larger than a predetermined amount of a normal regeneration start condition. Determining that the amount is over-deposited, and the amount of particulate deposited on the filter is less than the specified amount and the time since the last regeneration of the filter Determining that the trapped amount of the fine particles in the filter is over-deposited when the fuel supply amount reaches a predetermined time or a specified supply amount greater than a predetermined time or a predetermined supply amount of the normal regeneration start condition, And when the particulate matter collected by the filter is less than the specified amount and the corrected differential pressure calculated from the differential pressure of the filter and the volume flow rate of the exhaust gas reaches the specified differential pressure, A step of determining that the amount of collected fine particles is excessive deposition, a regeneration temperature relating to regeneration of the filter, a first regeneration temperature during normal regeneration, and a time during the normal regeneration. A switch that can be switched between a second regeneration temperature that is lower than the temperature at which the over-deposition state determining means determines that over-deposition has occurred. Characterized in that it is configured to be connected to indicating means for the second regeneration temperature switch to.

  Thus, when the amount of fine particles deposited on the filter exceeds the specified amount, that is, in the “overdeposition state”, the indicating means is connected to the control means, and the switch is connected to the first means. By switching to the second regeneration temperature that is lower than the regeneration temperature, the DPF can be regenerated at the second regeneration temperature even in an over-deposited state. Therefore, since the filter can be regenerated even in an over-deposited state, there is no need to replace or remove the filter when the over-deposited state occurs, greatly reducing the effort involved in releasing the over-deposited state. Can be reduced.

  Further, the control means has a deposit amount calculating means for estimating the amount of particulates deposited on the filter from the operating state of the engine, and the second regeneration temperature corresponds to the amount of particulates deposited on the filter. The filter may be set to a temperature lower than a limit temperature at which no excessive temperature rise occurs in the filter.

  As a result, the filter can be regenerated without overheating even in the overdeposited state, and the overdeposited state can be released. Therefore, the safety of regeneration is high, and damage such as melting of the filter can be prevented.

  Further, the control means is a case where it is determined by the over-deposition state determination means that over-deposition has occurred, and the amount of fine particles deposited on the filter estimated by the estimated amount calculation means during regeneration of the filter The second regeneration temperature may be changed with time according to the time change.

  By changing the second regeneration temperature according to the amount of particulates deposited on the filter, the second regeneration temperature can be made as high as possible according to the state of particulates deposited on the filter being regenerated. . Therefore, the regeneration time at the second regeneration temperature, which is lower than the first regeneration temperature, can be shortened as much as possible, and the time for canceling the overdeposition state can be set appropriately. Thereby, the risk of oil dilution that the oil used in the engine, which increases as the regeneration of the filter becomes longer, dilutes can be reduced.

The second regeneration temperature does not cause an excessive temperature rise in the filter during regeneration when the amount of fine particles collected by the filter is a prescribed amount that is a criterion for determination in the over-deposition state determining means. It may be set to a constant value below the limit temperature.
Thereby, although it takes a regeneration time, the over-deposition state can be canceled by performing the regeneration at the second regeneration temperature more safely.

  The control means is a case where the over-deposition state determination means determines that over-deposition occurs, and the amount of fine particles deposited on the filter estimated by the accumulation amount calculation means by the regeneration of the filter is When the amount of fine particles collected by the filter is equal to or less than a prescribed amount that is a criterion for determination in the over-deposition state determination means, the switch may be forcibly switched to the first regeneration temperature.

  In this way, after regeneration at the second regeneration temperature, the amount of particulates deposited on the filter is reduced to an amount that can be regenerated at the first regeneration temperature. By regenerating at a regeneration temperature of 1, the time required for the entire regeneration of the filter can be shortened.

The control means may prohibit the regeneration of the filter when the fine particles accumulated on the filter reach a certain amount larger than the specified amount.
The fixed amount is set to a deposition amount that causes an excessive temperature rise during regeneration even by the second regeneration temperature. Thereby, the safety | security in the reproduction | regeneration by said 2nd reproduction | regeneration temperature becomes higher.

  Further, as an invention relating to an engine exhaust purification method for solving the problem, in the present invention, particulates in exhaust gas are collected by a filter provided in an exhaust passage of the engine, and the particulates collected by the filter In a method for purifying the exhaust of an engine in which the regeneration of the filter is performed by injecting fuel at a time when it does not contribute to combustion in the combustion chamber of the engine when it becomes equal to or greater than a predetermined amount, and performing combustion with an oxidation catalyst, When the particulates collected by the filter become a specified amount greater than a predetermined amount of the normal regeneration start condition, and when the particulates collected by the filter are less than the prescribed amount and from the previous regeneration of the filter. When the elapsed time or the fuel supply amount reaches a predetermined time or a predetermined supply amount larger than the predetermined time or the predetermined supply amount of the normal regeneration start condition, and When the particulate matter collected by the filter is less than the specified amount and the corrected differential pressure calculated from the differential pressure of the filter and the volume flow rate of the exhaust gas reaches the specified differential pressure, the When it is determined that the amount of collected particulates is in an over-deposition state and over-deposition is determined, the regeneration temperature for regeneration of the filter is determined based on the first regeneration temperature during normal regeneration and the temperature during normal regeneration. An instruction means for forcibly switching the switch to the second regeneration temperature is connected to a switch that can switch between the second regeneration temperature, which is also a low temperature, and the regeneration temperature for regeneration of the filter is set to the second The regeneration temperature is characterized by the following.

  Further, the amount of particulates accumulated on the filter is estimated from the operating state of the engine, and the second regeneration temperature corresponds to the amount of particulates deposited on the filter, and does not cause excessive temperature rise in the filter during regeneration. It is good to set below the limit temperature.

  The second regeneration temperature is a case where it is determined that the over-deposition state is present, and it is preferable that the second regeneration temperature is changed over time according to a change over time in the amount of fine particles deposited on the filter during regeneration of the filter.

  The second regeneration temperature does not cause an excessive temperature rise in the filter during regeneration of the filter when the accumulation amount of fine particles on the filter is the prescribed amount that is a criterion for determining the overdeposition state. It may be set to a constant value below the limit temperature.

  Further, when the filter is regenerated at the second regeneration temperature that is determined to be overdeposition, the amount of fine particles accumulated on the filter is determined based on the amount of fine particles accumulated on the filter. The switch may be forcibly switched to the first regeneration temperature when the reference amount is below the reference amount.

In addition, when the filter is regenerated at the second regeneration temperature, the temperature may be raised to the regeneration temperature at a slower temperature increase rate than when the filter is regenerated at the first regeneration temperature.
As a result, the maximum temperature reached inside the filter can be suppressed, an excessive temperature rise can be prevented, and the DPF can be regenerated more safely.
Furthermore, it is possible to prevent the actual temperature at the inlet of the filter from causing an overshoot, and it is possible to regenerate the DPF more safely against an excessive temperature rise.

In addition, after the regeneration of the filter at the second regeneration temperature is completed, the oil used for the engine is replaced.
By regenerating the filter at the second regeneration temperature, that is, at a low temperature, the regeneration time is prolonged and the oil dilution risk that the oil used in the engine is diluted increases. Therefore, by exchanging the oil after completion of regeneration of the filter at the second regeneration temperature, it is possible to prevent occurrence of trouble due to oil dilution of the engine after completion of regeneration.

Also, a filter provided in the exhaust passage of the engine that collects particulates in the exhaust gas and performs forced regeneration to remove the collected particulates by heating, and a filter disposed upstream of the filter. An engine exhaust purification device having an oxidation catalyst for raising the temperature and a regeneration control means for regenerating the filter by regenerating the particulates deposited on the filter, the control means in the filter When the collected fine particles are larger than a specified amount larger than a predetermined amount of the normal regeneration start condition, or the fine particles collected in the filter are less than the specified amount and the elapsed time from the previous regeneration of the filter or The fine particles to the filter when the fuel supply amount reaches a predetermined time or a predetermined supply amount greater than a predetermined time of a normal regeneration start condition or a predetermined supply amount The over-deposition state determination means for determining that the trapped amount is over-deposition, and the regeneration temperature for regeneration of the filter are lower than the first regeneration temperature during normal regeneration and the temperature during normal regeneration. A switch capable of switching between the second regeneration temperature and connected to the control means when the overdeposition state determination means determines that overdeposition is present; An instruction means capable of setting the regeneration temperature and a server communicable with the instruction means are provided, and when the instruction means is connected to the control means, the information on the engine read from the control means The transmission to the server and the switch are switched to perform reproduction at the second reproduction temperature, and after the reproduction is completed, information indicating that the reproduction has been performed is transmitted to the server.
When the server verifies whether or not to permit switching of the switch by the instructing means by collating information relating to the engine transmitted from the instructing means with a database held therein, The permission information may be transmitted to the instruction means, and the instruction means may switch the switch based on the permission information from the server.

Thus, the holder of the instruction means can collect the work fee from the user of the vehicle equipped with the exhaust emission control device of the engine by performing the regeneration operation of the filter using the instruction means. .
Further, the holder of the server receives the information from the instruction unit, transmits permission information to the instruction unit, and receives information indicating that the reproduction has been performed from the instruction unit, whereby the instruction unit It is possible to reliably grasp the usage status of. In addition, since the information related to the engine and the information indicating that the regeneration has been performed are received from the instruction means, it is possible to grasp the usage status of the engine and the exhaust purification device, the regeneration status of the filter, and the like in the market.

  In addition, after the regeneration at the second regeneration temperature is completed, the instructing means displays a prompt to replace the engine oil, and replaces the oil when the engine oil is replaced based on the display. Information to that effect may be transmitted to the server.

  Accordingly, the oil is surely replaced after the regeneration of the filter at the second regeneration temperature is completed, and troubles due to the oil dilution of the engine after the regeneration is completed can be prevented.

The server may charge a predetermined service fee to a user of the instruction unit based on information transmitted from the instruction unit.
Since the service fee is collected based on the information transmitted from the instruction unit, the service fee can be reliably collected from the holder of the instruction unit.

  According to the present invention, in an engine exhaust gas purification apparatus that is provided in an engine exhaust passage and has a filter that collects particulates in exhaust gas, an “over-deposition state” in which the soot collected by the filter accumulates a predetermined amount or more. Even in this case, it is possible to provide an engine exhaust purification apparatus and method that can regenerate the filter without adding new parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram around an engine to which an exhaust emission control device according to Embodiment 1 is applied. 3 is a flowchart according to a DPF regeneration procedure in the first embodiment. It is the table | surface summarized about the collection stage in Example 1. FIG. It is the graph which put together the relationship between the collection stage division | segmentation in Example 1, and the soot accumulation amount of DPF34. 3 is a flowchart relating to determination of a collection stage in the first embodiment. It is a figure which concerns on calculation of each parameter which concerns on the collection stage judgment in Example 1. FIG. It is a figure which shows the logic of control of slow reproduction | regeneration. It is the graph which showed the relationship between PM limit accumulation amount at the time of regeneration of DPF, and DPF entrance control temperature. The time change of the reduction | decrease in PM deposit amount by the DPF inlet_port | entrance temperature at the time of regeneration of DPF is shown. It is a graph for demonstrating switching from slow reproduction | regeneration to manual reproduction | regeneration. It is a graph showing the relationship between the DPF inlet temperature and the elapsed time from the start of regeneration. It is the graph which showed the relationship between the maximum temperature inside DPF, and a temperature increase rate.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is a configuration diagram around an engine to which the exhaust emission control device according to the first embodiment is applied.
An air supply passage 6 is joined to the engine 2 via an air supply manifold 4, and an exhaust passage 10 is connected to the engine 2 via an exhaust manifold 8.
The air supply passage 6 is provided with a compressor 12 a of a turbocharger 12. The compressor 12a is coaxially driven by a turbine 12b described later. An intercooler 14 that performs heat exchange between the intake air flowing through the air supply passage 6 and the atmosphere is provided downstream of the compressor 12a in the air supply passage 6. Further, a throttle valve 16 for adjusting the flow rate of intake air flowing through the air supply passage 6 is provided downstream of the intercooler 14 in the air supply passage 6.

  An air flow meter 26 that detects the supply air flow rate and an intake air temperature sensor 28 that detects the intake air temperature are provided on the upstream side of the compressor 12 a in the supply air passage 6, and detected values of the air flow meter 26 and the intake air temperature sensor 28. Is taken into an ECU (engine control unit) 50. An air supply absolute pressure sensor 18 for detecting the air supply absolute pressure and an air supply temperature sensor 20 for detecting the air supply temperature are provided downstream of the throttle valve 16 in the air supply passage 6. Detection values of the absolute pressure sensor 18 and the supply air temperature sensor 20 are taken into the ECU 50.

  In the exhaust passage 10, a turbine 12 b of the turbocharger 12 is provided. The turbine 12 b is driven by exhaust gas from the engine 2. The exhaust passage 10 is connected to an EGR passage 23 that recirculates part of the exhaust gas (EGR gas) to the supply side. The EGR passage 23 is provided with an EGR control valve 24 that controls the flow rate of EGR gas flowing through the EGR passage 23.

An exhaust purification device 30 that performs exhaust aftertreatment is provided on the exhaust passage 10 downstream of the turbine 12b. The exhaust purification device 30 detoxifies hydrocarbon (HC) and carbon monoxide (CO) in the exhaust gas by the action of the oxidation catalyst, oxidizes NO in the exhaust gas to NO ₂ , and collects the soot collected by the DPF 34. DOC (oxidation catalyst) 32 and DOC 32 having the function of burning and removing soot and the function of raising the exhaust gas temperature by the oxidation reaction heat of the unburned components in the exhaust gas when the soot collected in the DPF 34 is forcibly regenerated And a DPF 34 that collects soot in the exhaust gas. Further, the exhaust purification device 30 is provided with a DOC inlet temperature sensor 36 for detecting the inlet temperature of the DOC 32, a DPF inlet temperature sensor 38 for detecting the inlet temperature and the outlet temperature of the DPF, and a DPF outlet temperature sensor 42, respectively. The detected values of the DOC inlet temperature sensor 36, the DPF inlet temperature sensor 38, and the DPF outlet temperature sensor 42 are taken into the ECU 50. In addition, a DPF differential pressure sensor 40 that detects the differential pressure at the entrance and exit of the DPF 34 is provided, and the detection value of the DPF differential pressure sensor 40 is also taken into the ECU 50.

In addition, the engine 2 is provided with an injector, a rail pressure sensor, a fuel temperature sensor, a crank sensor, a cam sensor, a water temperature sensor, a hydraulic switch, and the like as parts that exchange information with the ECU 50. These parts are collectively indicated by 22 in FIG.
Further, the ECU 50 calculates the target opening degree of the EGR control valve 24 and the throttle valve 18 based on each of the above-described values and controls the opening degree of the EGR control valve 24 and the throttle valve 18.
Further, the ECU 50 receives an accelerator input signal through the cable 44, and is connected to a vehicle body ECU (not shown) through the cable 46.

  In the above configuration, the DPF 34 constituting the exhaust purification device 30 collects soot that is fine particles (PM) in the exhaust gas, and the amount of soot accumulation is limited. Therefore, it is necessary to remove the soot accumulated on the DPF 34 and perform regeneration.

The regeneration of the DPF 34 in the present embodiment will be described with reference to FIGS.
FIG. 2 is a flowchart according to the regeneration procedure of the DPF 34 according to the first embodiment.

In FIG. 2, when the process starts, that is, when the ECU 50 operates, the process proceeds to step S1.
In step S1, the ECU 50 determines whether or not the current state of the DPF 34 is an over-deposition state, that is, whether or not it is the collection stage 5 or 6.

Here, the collection stage will be described.
FIG. 3 is a table summarizing the collection stage in the first embodiment. If the collection stage is the collection stage 1, it is not necessary to regenerate the DPF 34, the stage 2 needs to automatically regenerate the DPF, the stages 3 and 4 need to perform manual regeneration of the DPF, and the stage 5 is slowly described later. Regeneration is required, and stage 6 is in a state where DPF cannot be regenerated.

  The collection stage summarized in FIG. 3 can be determined by, for example, the soot accumulation amount of the DPF 34. FIG. 4 is a graph summarizing the relationship between the collection stage classification and the soot accumulation amount of the DPF 34 in the first embodiment. In FIG. 4, the vertical axis represents the collection stage, and the horizontal axis represents the soot accumulation amount of the DPF 34.

  As shown in FIG. 4, the collection stage is determined by the soot accumulation amount of the DPF 34, and the collection stage becomes larger as the soot accumulation amount is larger. In the present embodiment shown in FIG. 4, when the soot accumulation amount is Q2 [g / L] or less, the collection stage 1, and when the soot accumulation amount is Q3 [g / L] or less, the collection stage 2 and the soot accumulation amount are Q4. Below [g / L], the collection stage 3; when the soot accumulation amount is Q5 [g / L] or less, the collection stage 4; when the soot accumulation amount is Q6 [g / L] or less, the collection stage 5 and the soot accumulation amount are It is the collection stage 6 above Q6 [g / L]. Such a graph is stored in the ECU 50 in advance.

FIG. 5 is a flowchart relating to determination of the collection stage in the first embodiment, and the ECU 50 determines the collection stage according to the flowchart shown in FIG. 5.
In FIG. 5, when the process is started, the current collection stage is determined in step S51, and the process proceeds to step S52. The current collection stage in step S51 means the collection stage determined one cycle before the flowchart in FIG. 5 and is stored in the ECU 50.

  When the current collection stage is determined, in step S53, the estimated state of soot accumulation amount ≧ Qx, cumulative operation time ≧ Tx, cumulative fuel consumption amount ≧ Qfx, DPF correction differential pressure ≧ dPx, In addition, it is determined whether or not the state has continued for a predetermined time.

The determination in step S53 will be described with reference to FIG.
FIG. 6 is a diagram related to calculation of each parameter according to the collection stage determination in the first embodiment. In FIG. 6, reference numeral 101 denotes a soot estimated amount calculation, which means calculation of an estimated value of the soot amount accumulated in the DPF 34. In the estimated soot amount calculation 101, the engine exhaust speed is calculated at 102 using the detected values of the engine speed, the fuel injection amount to the engine, and the excess oxygen ratio, and at 103, the engine speed is calculated. The soot regeneration amount is calculated using detected values of the fuel injection amount, the exhaust gas flow rate, the DOC inlet temperature, the DPF inlet temperature, and the DPF outlet temperature. Next, the calculated values of the soot discharge amount and the soot regeneration amount calculated in 104 are added, integrated in 105, and divided by the capacity of the DPF 34 in 106 to obtain an estimated value [g / L] of the soot accumulation amount. It is done. Then, at 100, the soot accumulation amount obtained at 106 is equal to or greater than Qx corresponding to the collection stage X determined at step S51 in FIG. Judgment is made using the graph as shown in FIG.

In addition, a graph similar to that shown in FIG. 4 is stored in the ECU 50 in advance for the accumulated operation time from the previous regeneration of the DPF 34, the accumulated fuel consumption from the previous regeneration of the DPF 34, and the corrected differential pressure before and after the DPF. ing. From the cumulative operation time calculated at 111, the cumulative fuel consumption calculated from the fuel injection amount to the engine at 121, the fuel injection amount, the supply air flow rate, the DPF inlet temperature, the DPF outlet temperature, and the DPF differential pressure at 131 Whether the calculated differential pressure difference is equal to or greater than Tx, Qfx, dPx corresponding to the collection stage X determined in step S51 in FIG. The determination is made using a graph similar to the graph shown in FIG.
Here, the corrected differential pressure is standard based on the ratio of the exhaust gas volume flow rate to the reference gas amount because the differential pressure across the DPF 34 changes depending on the exhaust gas volume flow rate even if the soot accumulation amount on the DPF 34 is the same. It is converted into a differential pressure before and after the DPF 34 in the state.

  That is, in step S53 shown in FIG. 5, the soot accumulation amount estimated value, the accumulated operation time, the accumulated fuel consumption amount, and the DPF correction differential pressure are calculated, and the calculated values are set to predetermined amounts (Qx, Tx, Qfx, dPX). ) It is determined whether or not the above state continues for a certain period of time. In step S53, if any one of the estimated soot accumulation value, the accumulated operation time, the accumulated fuel consumption amount, and the DPF correction differential pressure continues to be equal to or greater than the predetermined value for the predetermined time. Judge as YES.

  In the flowchart shown in FIG. 5, if NO is determined in step S53, the process is terminated as it is, and the current collection stage determined in step S51 is determined as the collection stage.

  If “YES” is determined in the step S53, the process proceeds to a step S54 to determine whether or not the current state is that the DPF 34 is being regenerated. If YES in step S54, that is, if the DPF 34 is currently being regenerated, the process is terminated, and the current collection stage determined in step S51 is determined as the collection stage. If NO in step S54, that is, if the DPF 34 is not currently being regenerated, the process proceeds to step S55, where the collection stage obtained by adding 1 to the current collection stage determined in step S51 is determined, and the process ends.

  When the collection stage is determined by the flowchart shown in FIG. 5, in step S <b> 1 in the flowchart shown in FIG. 2, if the determined collection stage is 5 or 6, it is determined as an over-deposition state and YES When the collection stage is 1 to 4, it is determined that it is not an excessive deposition state, and the process proceeds to NO.

If NO is determined in step S1, the process is terminated as it is.
If YES is determined in the step S1, the process proceeds to a step S2.
In step S2, the output of the engine is limited by an instruction from the ECU 50, and a warning lamp (not shown) provided in the driver's seat or the like is used to notify a user such as a driver that the DPF 34 is in an over-deposited state.

When step S2 ends, the process proceeds to step S3.
In step S3, a user who has confirmed that the DPF 34 is in an over-deposited state by checking the warning lamp or the like contacts a service base that owns a service tool described later, such as a dealer or a repair factory.

  When step S3 ends, a service person is dispatched from the service base that received the communication in step S4. Alternatively, a vehicle or the like on which the engine purification device 30 according to this embodiment is mounted may be brought into the service base. The service person determines whether the DPF 34 is in the collection stage 5 state.

If YES in step S4, that is, if it is determined to be the collection stage 5, the process proceeds to step S5.
In step S5, the service person connects the ECU 50 to the service tool that he / she brings. The service tool will be described later.

  When step S5 ends, in step S6, the service staff slowly regenerates the DPF using a service tool.

Here, the slow reproduction will be described.
Generally, when the DPF is regenerated, the inlet temperature of the DPF is controlled to be about 600 ° C., but the slow regeneration is performed over a long time at a low temperature such as 530 ° C. to prevent overheating. Is what you do.

FIG. 7 is a diagram illustrating the logic of the slow reproduction control.
During normal regeneration, the switch 203 for regeneration control is on the 201 side. For example, as in 201, the target is a DPF inlet temperature of 600 ° C., 206 is compared with the detected value of the DPF inlet temperature, and 207 is PID calculation. Then, at 208, the late post-injection amount of the fuel related to the regeneration of the DPF is determined.

  At the time of slow reproduction, the service tool 204 is connected to the switch 203. The service tool 204 is connected, and an intention to perform slow playback such as pressing a slow playback start button displayed on the operation screen of the service tool 204 is shown. As a result, the service tool 204 can acquire information about the engine 2 and the exhaust emission control device 30 including information on the collection stage from the ECU 50, and the information can be communicated with the service tool 204 by a communication means such as LAN or wireless. To the server 205. The server 205 that has received the information checks the information against an internal database to determine whether or not to permit switching of the switch by the instruction means, and transmits permission information to the service tool. Upon receiving the permission information, the service tool 204 slowly turns on the reproduction flag. When the slow regeneration flag is turned ON, the ECU 50 recognizes that the regeneration is slow and switches the regeneration control switch to the map 202 side for slowly determining the target temperature of the DPF inlet according to the regeneration.

  In addition to the slow regeneration of the DPF, the service tool 204 writes data (software parameters) to the ECU, monitors the ECU state, and reads the data through communication with the ECU 50. At this time, the ECU model number, software Identify the unique number of the version of the injector. The service tool 204 also performs data download from the server and data read from the ECU by communicating with the server 205 via a LAN or wireless communication. Further, during slow regeneration or ash maintenance, the ECU, engine, injector, DPF identification number, and data stored in the ECU's non-volatile memory (operating state of the engine / DPF by the user) are read and uploaded to the server.

  Here, a map for determining the target temperature of the DPF inlet corresponding to the slow regeneration indicated by 202 in FIG. 7 will be described.

  FIG. 8 is a graph showing the relationship between the PM limit accumulation amount and the DPF inlet control temperature when the DPF 34 is regenerated. In FIG. 8, the vertical axis indicates the PM limit deposition amount, and the PM limit deposition amount means the maximum soot deposition amount that allows the regeneration of the DPF 34 to be performed stably without excessive temperature rise. In FIG. 8, the horizontal axis indicates the DPF inlet control temperature. From FIG. 8, it can be seen that there is a negative first-order correlation between the PM limit accumulation amount and the DPF inlet control temperature. That is, as the amount of soot accumulated on the DPF increases, the DPF inlet control temperature must be lowered.

  FIG. 9 shows the change over time in the decrease in the amount of accumulated PM due to the inlet temperature of the DPF when the DPF 34 is regenerated. In FIG. 9, the vertical axis represents the amount of PM deposited on the DPF, and the horizontal axis represents the regeneration time. The inlet temperature of the DPF is 530 ° C., 570 ° C., 580 ° C., 590 ° C., 600 ° C., 610 ° C., 620 ° C. The time change of the reduction | decrease of PM deposit amount by reproduction | regeneration from the same PM deposit amount in 630 degreeC is shown. FIG. 9 shows that the lower the DPF inlet temperature, the longer the regeneration.

From this, it can be said that two methods can be selected for the DPF inlet temperature during slow regeneration.
The first method is to always set and control the inlet temperature of the DPF 34 to a temperature corresponding to the soot accumulation amount. Here, the temperature corresponding to the soot accumulation amount is a temperature equal to or lower than the DPF inlet control temperature in which the soot accumulation amount at that time is the PM limit accumulation amount. In this case, the target temperature of the DPF 34 during regeneration changes according to the soot accumulation amount. Thereby, it is possible to always perform the reproduction safely and to appropriately set the reproduction time as short as possible.
The second method is to make the inlet temperature of the DPF 34 constant at a safe low temperature regardless of the soot accumulation amount such as 530 ° C., for example. Thereby, although it takes a reproduction time, the reproduction can be performed more safely.
Therefore, in the map indicated by 202 in FIG. 7, when the first method is used, the map indicating the target value of the DPF inlet control temperature according to the soot accumulation amount uses the second method. In this case, a specified value (for example, 530 ° C.) of the target value of the DPF inlet control temperature at the time of DPF regeneration is stored instead of the map.

In the flowchart shown in FIG. 2, when the regeneration is started slowly in step S6, the process proceeds to step S7 (a) or step S7 (b), and the target temperature at the DPF inlet is set to the map shown in FIG. In step S8, regeneration is continued slowly until the soot accumulation amount estimated value reaches below the manual regeneration possible threshold value.
Here, step S7 (b) corresponds to the first method described above, and step S7 (a) corresponds to the second method described above, and either can be selected.

  In step S8, when the estimated soot accumulation amount reaches less than the manual regeneration possible threshold value by slow regeneration, the process proceeds to step S9 (a), and the ECU automatically switches from slow regeneration to normal manual regeneration. Further, instead of step S9 (b), the regeneration can be ended slowly in step S9 (b), and the manual regeneration can be started in step S10. Here, the manual regeneration possible threshold means the maximum value of the estimated soot accumulation amount at which manual regeneration can be performed, and corresponds to Q5 [g / L] in FIG.

  FIG. 10 is a graph for explaining switching from slow regeneration to manual regeneration. In FIG. 10, the vertical axis indicates the PM deposition amount [g / L], and the horizontal axis indicates the regeneration time. For example, when the target temperature at the entrance of the DPF is controlled to be constant at 530 ° C. in step S7 (a) of the flowchart in FIG. 2 and the manual regeneration threshold is the PM deposition amount a [g / L], PM deposition is performed. Reproduction is performed slowly until the amount decreases below a [g / L] (reproduction time of about 27 minutes in FIG. 10), and thereafter manual regeneration is performed.

  In the flowchart shown in FIG. 2, when manual regeneration is started in step S9 (a) or step S9 (b) → step S10, the estimated value of the soot accumulation amount is less than the prescribed regeneration completion threshold value and the regeneration time Manual regeneration is continued until becomes longer than the prescribed regeneration completion threshold, and the manual regeneration is completed in step S12.

  When the regeneration is completed in step S12, a message prompting the service tool to change oil is displayed in step S13.

Up to this point, the case of YES in step S4, that is, the case of the collection stage 5 has been described.
The collection stage 6 is an area where the soot accumulation amount on the DPF 34 is too large to be slowly regenerated. Therefore, in step S14, the service person removes the DPF or removes the DPF to remove the soot for cleaning. In step S15, the service tool is connected to the ECU 50, and the soot accumulation amount is reset by the service tool. A prompt message appears.

  When a message prompting oil change is displayed on the service tool in step S13 or step S15, the service person performs oil change in step S16. This is because there is a possibility that oil dilution (dilution) may occur due to slow regeneration or replacement or cleaning of the DPF.

  When the service person performs oil change in step S16, the service person proceeds to step S17 and presses an oil change completion button displayed on the service tool. The oil change completion button is provided in order to carry out the oil change with certainty. When the oil change completion button is not pressed, the operation of the engine is limited.

  When the service person presses the oil change completion button in step S17, the service tool is connected to the server 205 in step S18, information is uploaded to the server in step S19, and the service tool is removed from the ECU 50 in step S20 to complete the service. Then, the process ends.

  According to the present embodiment, the DPF can be regenerated by slow regeneration in the collection mode 5 even in an over-deposited state. As a result, the opportunity for cleaning by exchanging or removing the DPF can be reduced.

  In addition, since control is performed at a safe temperature that does not cause excessive temperature rise even in an overdeposited state, the DPF can be prevented from being melted even when the DPF is regenerated in an overdeposited state.

  Furthermore, by controlling the temperature of the DPF inlet and controlling the DPF regeneration temperature, the regeneration time can be shortened, and the oil dilution risk resulting from the regeneration of the DPF can be reduced.

  In addition, since the information on the slow regeneration and oil change is uploaded to the server, the owner of the server can reliably grasp the usage status of the service tool. In addition, if the service tool and the server user are different, such as when the service tool is lent out under a usage contract, the server user must ensure that the service tool user pays a service fee according to the usage status. Can be collected.

  In the second embodiment, the configuration around the engine is the same as the configuration of the first embodiment shown in FIG. 1, and the procedure related to the DPF regeneration procedure is the same as the procedure in the first embodiment shown in the flowchart of FIG. Since it is the same, the description is abbreviate | omitted. The same applies to FIGS. 3 to 10 described in the first embodiment and also in the second embodiment.

  In the second embodiment, when the target temperature is determined by the map 202 shown in FIG. 7, the target temperature is increased to the determined target temperature at a speed slower than normal regeneration. That is, a rate limit is applied to the target temperature.

  FIG. 12 is a graph showing the relationship between the maximum temperature inside the DPF and the rate of temperature increase. The vertical axis represents the maximum temperature inside the DPF, and the horizontal axis represents the target temperature temperature increase rate. In FIG. 12, the final target temperature and the temperature at the start of temperature increase are the same. As shown in FIG. 12, even when the target temperature is increased from the same temperature to the same temperature, it can be seen that the maximum temperature reached in the DPF varies depending on the rate of temperature increase. That is, it can be seen that the slower the rate of temperature rise, the lower the DPF internal temperature. Therefore, by applying a rate limit to the target temperature and slowing the rate of temperature rise, the maximum temperature reached inside the DPF can be suppressed, overheating can be prevented, and the DPF can be regenerated more safely. it can.

FIG. 11 is a graph showing the relationship between the DPF inlet temperature and the elapsed time from the start of regeneration. In FIG. 11, the vertical axis represents the DPF inlet temperature, and the horizontal axis represents the elapsed time from the start of regeneration.
In FIG. 11, the graph indicated by a represents the time change of the target speed when the rate of temperature increase is not limited, and a ′ represents the time change of the actual temperature change at the DPF inlet in that case. Represents. Further, the graph indicated by b represents the time change of the target speed when the rate of temperature increase is rate-limited, and b ′ represents the time change of the actual temperature change at the DPF inlet in that case. . When the rate limit is not applied to the target temperature indicated by a ′, the actual temperature at the DPF inlet exceeds the target temperature and causes an overshoot, but the rate limit is applied to the target temperature indicated by b ′. In some cases, the actual temperature at the DPF inlet does not cause overshoot.
Therefore, by applying a rate limit to the target temperature and slowing the rate of temperature increase, it is possible to prevent the actual temperature of the DPF inlet from overshooting and exceeding the target temperature, and the excessive temperature increase. On the other hand, the DPF can be regenerated more safely.

  According to the present invention, in an exhaust emission control device for an engine having a filter provided in an exhaust passage of an engine and collecting particulates in exhaust gas, the soot collected by the filter is in an “over-deposition state” in which a predetermined amount or more is accumulated. Even in such a case, the present invention can be used as an exhaust gas purification apparatus and method for an engine capable of regenerating the filter without adding new parts. In addition, it can also be used as a filter regeneration system according to the engine exhaust gas purification apparatus.

2 Engine 10 Exhaust passage 30 Exhaust purification device 32 DOC
34 DPF
50 ECU (control means)
204 Service tool (instruction means)
205 servers

Claims (6)

A filter that is provided in the exhaust passage of the engine, collects particulates in the exhaust gas, and performs forced regeneration to remove the collected particulates by heating, and a filter disposed upstream of the filter In an exhaust emission control device for an engine having an oxidation catalyst for raising, and a regeneration control means for regenerating the fine particles accumulated on the filter to regenerate the filter,
The control means includes
Determining that the amount of particulates collected on the filter is excessively deposited when the amount of particulates deposited on the filter exceeds a specified amount greater than a predetermined amount of the normal regeneration start condition; and deposited on the filter When fine particles are less than the prescribed amount and the elapsed time or fuel supply amount from the previous regeneration of the filter reaches a prescribed time or prescribed supply amount greater than a prescribed time or a prescribed supply amount of a normal regeneration start condition, to the filter A step of determining that the amount of collected particulates is excessively deposited, and the amount of particulates collected by the filter being less than the specified amount, and being calculated from the differential pressure of the filter and the volumetric flow rate of the exhaust gas. Determining that the amount of particulates collected on the filter is over-deposited when the corrected differential pressure reaches a specified differential pressure. And means,
A switch capable of switching a regeneration temperature related to regeneration of the filter between a first regeneration temperature during normal regeneration and a second regeneration temperature lower than the temperature during normal regeneration;
When it is determined by the over-deposition state determining means that it is over-deposited, it is configured to be able to connect an instruction means for forcibly switching the switch to the second regeneration temperature ,
The control means includes
A deposition amount calculating means for estimating the amount of particulates deposited on the filter from the operating state of the engine;
It said second regeneration temperature, corresponding to the amount of particulate deposited on the filter, while being set to a limit temperature is a temperature that does not cause excessive Atsushi Nobori in the filter during regeneration,
The control means includes
When it is determined by the over-deposition state determining means that it is over-deposition, and during regeneration of the filter by the second regeneration temperature,
The second regeneration temperature is changed with time so that the second regeneration temperature becomes the limit temperature corresponding to the amount of fine particles accumulated on the filter estimated by the accumulation amount calculating means. Exhaust gas purification device for the engine. The control means includes
When it is determined by the over-deposition state determining means that the particles are over-deposited, the amount of fine particles accumulated on the filter estimated by the accumulation amount calculating means is collected by the filter due to regeneration of the filter. and if the amount of particulate becomes less than a specified amount as a determination reference in the over-deposition state judging means, to claim 1, characterized in that the first regeneration temperature by switching the switch to force The engine exhaust gas purification apparatus as described. The control means includes
3. The engine exhaust gas purification apparatus according to claim 1, wherein regeneration of the filter is prohibited when fine particles accumulated on the filter reach a certain amount larger than the specified amount. 4. When particulates in the exhaust gas are collected by a filter provided in the exhaust passage of the engine and the particulates collected by the filter exceed a predetermined amount, they do not contribute to combustion in the combustion chamber of the engine In an engine exhaust purification method for regenerating the filter by injecting fuel and performing combustion with an oxidation catalyst,
When the particulates collected by the filter become a specified amount greater than a predetermined amount of the normal regeneration start condition, and when the particulates collected by the filter are less than the prescribed amount and from the previous regeneration of the filter. When the elapsed time or the fuel supply amount reaches a predetermined time or a predetermined supply amount larger than a predetermined time or a predetermined supply amount of the normal regeneration start condition, and the particulates collected by the filter are less than the predetermined amount and the filter When the corrected differential pressure calculated from the differential pressure of the exhaust gas and the volume flow rate of the exhaust gas reaches a specified differential pressure, it is determined that the collected amount of the fine particles to the filter is in an over-deposited state,
A switch capable of switching between a first regeneration temperature at the time of normal regeneration and a second regeneration temperature lower than the temperature at the time of normal regeneration, when the regeneration temperature is determined to be excessive. In addition, an instruction means for forcibly switching the switch to set the second regeneration temperature is connected, and the regeneration temperature for regeneration of the filter is set as the second regeneration temperature ,
Estimating the amount of particulates deposited on the filter from the operating state of the engine,
It said second regeneration temperature, corresponding to the amount of particulate deposited on the filter, and sets the limit temperature is a temperature that does not cause excessive Atsushi Nobori in the filter during regeneration,
The second regeneration temperature is determined to correspond to the amount of fine particles accumulated on the filter during regeneration of the filter at the second regeneration temperature when the over-deposition state is determined. An exhaust purification method for an engine, characterized in that the second regeneration temperature is changed over time so as to reach a temperature. By regenerating the filter at the second regeneration temperature that is determined to be overdeposition, the amount of fine particles accumulated on the filter is determined based on the amount of fine particles accumulated on the filter as a criterion for determining the overdeposition state. The engine exhaust purification method according to claim 4 , wherein the switch is forcibly switched to a first regeneration temperature when the predetermined amount or less is reached. The engine exhaust purification method according to claim 4 or 5 , wherein oil used in the engine is replaced after the regeneration of the filter at the second regeneration temperature is completed.

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