Control device and notification method

Abstract

To notify that a problem exists in an operation state or the like in forcible regeneration.SOLUTION: A control device comprises a notification part for notifying that a problem exists in an operation state of an engine when the number of times at which it is estimated that a temperature of an exhaust emission becomes lower than a light-off temperature for a prescribed time or longer exceeds a prescribed threshold, in a case where forcible regeneration for forcibly raising the temperature of the exhaust emission is performed in an exhaust gas post-treatment device which has a filter for collecting particulate substances in the exhaust emission of the engine and an oxidation catalyst arranged at an upstream side of the filter, and regenerates the filter by an action of the oxidation catalyst.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a control device and a notification method. [Background technology]

[0002] As described in Patent Document 1, in an exhaust gas purification device for a diesel engine, when the exhaust gas temperature is maintained above the light-off temperature (activation temperature) of the catalyst of the filter for a predetermined time (for example, several minutes), the trapped particulate matter is burned and the filter is regenerated (self-regenerated); however, when the exhaust gas temperature does not reach the activation temperature, or when the exhaust gas temperature reaches the activation temperature but drops before regeneration is completed, particulate matter accumulates in the filter. As a method of regenerating a filter to avoid such a situation, there is a forced regeneration method in which the exhaust gas temperature is forcibly raised to remove particulate matter. There are two types of forced regeneration: automatic regeneration, which is performed automatically when certain conditions are satisfied, and manual regeneration, which is performed at any timing by the driver's operation. However, in a work machine, even if forced regeneration is performed automatically or manually, the engine is frequently stopped, and the engine speed fluctuates greatly depending on the work content and work load, so that particulate matter tends to accumulate even when forced regeneration is performed.

[0003] Therefore, the working machine described in Patent Document 1 is a working machine equipped with an exhaust purification device that collects particulate matter in the exhaust gas of a diesel engine with a filter and burns the collected particulate matter to regenerate the filter, and is equipped with a regeneration determination means that determines that forced regeneration has failed during forced regeneration of the filter, for example, when the exhaust temperature reaches a threshold value indicating that regeneration is possible, and a notification means that notifies the fact that forced regeneration has failed when the number of times that the regeneration determination means determines that forced regeneration has failed reaches a predetermined threshold value or more. In the working machine described in Patent Document 1, for example, when automatic regeneration of the filter fails a predetermined number of times, a warning message indicating that forced regeneration has failed, the number of times regeneration has failed, and the reason for the regeneration failure, such as a drop in exhaust temperature, are notified. And, according to the working machine described in Patent Document 1, even if regeneration failures occur frequently due to the usage pattern of the working machine, it is possible to prevent frequent indications that regeneration has failed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-203297 A Summary of the Invention [Problem to be solved by the invention]

[0005] The work machine described in Patent Document 1 can notify the user of the reason for the failure of regeneration, such as a drop in exhaust temperature, after regeneration has failed, but has the problem of not being able to notify the user of a problem with the operating conditions, etc., during forced regeneration when regeneration does not fail or when regeneration fails for other reasons.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a control device and a notification method that can notify the user that there is a problem with the operating state or the like during forced regeneration. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention is a control device in an exhaust gas aftertreatment device having a filter that captures particulate matter in engine exhaust and an oxidation catalyst provided upstream of the filter, and regenerating the filter by the action of the oxidation catalyst, the control device being equipped with a regeneration state determination unit that notifies the user that there is a problem with the operating state of the engine when forced regeneration is being performed to forcibly raise the temperature of the exhaust, and the number of times it is estimated that the temperature of the exhaust has fallen below the light-off temperature for a predetermined period of time exceeds a predetermined threshold value.

[0008] Another aspect of the present invention is a notification method in an exhaust gas aftertreatment device having a filter that captures particulate matter in engine exhaust and an oxidation catalyst provided upstream of the filter, and regenerating the filter by the action of the oxidation catalyst, which includes a step of notifying the user when forced regeneration is being performed to forcibly raise the temperature of the exhaust, when the number of times it is estimated that the temperature of the exhaust has fallen below the light-off temperature for a predetermined period of time exceeds a predetermined threshold value. Effect of the Invention

[0009] According to each aspect of the present invention, it is possible to notify the user that there is a problem with the operating state or the like during forced regeneration. [Brief description of the drawings]

[0010] [Figure 1] 1 is a system diagram showing a configuration example of an engine control system according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing an example of the configuration of a control device 100 shown in FIG. [Diagram 3] 3 is a timing chart illustrating an example of the operation of the control device 100 illustrated in FIG. 2. [Figure 4] 2 is a timing chart showing a schematic example of an operation of the engine control system shown in FIG. 1. [Diagram 5] 3 is a flowchart showing an example of the operation of the regeneration target temperature reset unit 104 shown in FIG. 2. [Figure 6]3 is a control block diagram showing a playback state determination unit 105 shown in FIG. 2. [Figure 7] 3 is a flowchart showing an example of the operation of the playback state determination unit 105 shown in FIG. 2. [Figure 8] 3 is a schematic diagram for explaining an example of the operation of the playback state determination unit 105 shown in FIG. 2. [Figure 9] 3 is a schematic diagram for explaining an example of the operation of the playback state determination unit 105 shown in FIG. 2. [Figure 10] 3 is a flowchart showing an example of the operation of the playback state determination unit 105 shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding components are designated by the same reference numerals and the description thereof will be omitted as appropriate.

[0012] (Engine Control System 10) Fig. 1 is a system diagram showing an example of the configuration of an engine control system 10 as an example of the configuration of an exhaust gas purification system according to each embodiment of the present invention. The engine control system 10 shown in Fig. 1 includes an engine 1, an exhaust pipe 3, a DPF device 5 as an example of the configuration of an exhaust gas aftertreatment device, a monitor 8, a control device 100, and an HC dozer 7. Note that Fig. 1 and other figures mainly show the configuration related to forced regeneration of the DPF device 5 in the engine control system 10 (or the control device 100) of this embodiment, and the configuration related to other functions such as fuel injection control is appropriately omitted.

[0013] The engine 1 is an example of an internal combustion engine, and in this embodiment is a multi-cylinder diesel engine. An exhaust pipe 3 discharges exhaust gas from the engine 1 through a DPF device 5 into the atmosphere.

[0014] The DPF device 5 is a device that purifies particulate matter (PM (Particulate Matter)) contained in the exhaust gas of the engine 1, and has a DOC (Diesel Oxidation Catalyst) 51 provided in the exhaust pipe 3 of the engine 1, and a DPF (Diesel Particulate Filter) 52 that is a filter that collects PM in the exhaust gas of the engine 1. The DPF device 5 regenerates the DPF 52 by the action of the DOC 51. The DPF device 5 oxidizes the PM collected downstream to carbon dioxide using nitrogen dioxide converted by the DOC 51 provided upstream of the DPF 52, thereby removing the PM.

[0015] The DPF device 5 also has a DOC inlet temperature sensor 94 that detects the exhaust temperature at the inlet of the DOC 51, a DOC outlet temperature sensor 95 that detects the exhaust temperature at the outlet of the DOC 51, and a pair of pressure sensors 96 and 97 that detect the differential pressure between the inlet and outlet of the DPF 52. The detected values ​​of the DOC inlet temperature sensor 94, the DOC outlet temperature sensor 95, and the pressure sensors 96 and 97 are output to the control device 100.

[0016] The HC dozer 7 is an exhaust pipe fuel injection device that injects fuel (HC) into the exhaust pipe 3 upstream of the DOC 51 (hereinafter referred to as (HC dosing, etc.). HC dosing by the HC dozer 7 is controlled by the control device 100.

[0017] The monitor 8 has, for example, a display panel and an input panel, and functions as a display device and an input device, displaying specified characters and images in response to instructions from the control device 100, and outputting signals to the control device 100 in response to input operations by the user (operator).

[0018] In the engine control system 10 of this embodiment, forced regeneration (DPF regeneration operation) is periodically performed to burn PM accumulated in the DPF 52. In this forced regeneration, the temperature of the exhaust gas and the temperature of the DOC 51 are forcibly increased. The forced regeneration is performed by, for example, burning HC in the DOC 51 arranged upstream of the DPF 52 and increasing the temperature of the DPF 52 by post-injection for mixing fuel with the exhaust gas in the engine 1, or by a combination of post-injection and HC (fuel) dosing (injection) by the HC doser 7 into the exhaust pipe 3 upstream of the DPF device 5.

[0019] In the engine control system 10 of this embodiment, the forced regeneration (DPF regeneration operation) includes automatic regeneration, which is performed automatically in a normal operation state (a state in which normal operation and work can be performed without forcibly fixing the engine speed) when a certain condition is satisfied, and fixed manual regeneration (manual regeneration), which is performed at any timing by a user's operation. Fixed manual regeneration is a control that stops normal operation with the user's permission and restores the performance of the DPF device 5 when the exhaust temperature does not rise sufficiently in the normal operation state and the temperature of the DPF device 5 cannot be stably controlled to a target temperature. In fixed manual regeneration, the control device 100 first uses the monitor 8 to notify the user that the fixed manual regeneration is possible and to request the user to perform it. In response to this, when the user issues an instruction to perform fixed manual regeneration using the monitor 8, the control device 100 fixes the engine speed at a certain rotation, increases the exhaust temperature, and performs forced regeneration.

[0020] (Control device 100) 2 to 10, a configuration example and an operation example of the control device 100 shown in FIG. 1 will be described. FIG. 2 is a block diagram showing a configuration example of the control device 100 shown in FIG. 1. FIG. 3 is a timing diagram showing a typical operation example of the control device 100 shown in FIG. 2. FIG. 4 is a timing diagram showing a typical operation example of the engine control system 10 shown in FIG. 1. FIG. 5 is a flowchart showing an operation example of the regeneration target temperature reset unit 104 shown in FIG. 2. FIG. 6 is a control block diagram showing the regeneration state determination unit 105 shown in FIG. 2. FIG. 7 is a flowchart showing an operation example of the regeneration state determination unit 105 shown in FIG. 2. FIGS. 8 to 9 are schematic diagrams for explaining an operation example of the regeneration state determination unit 105 shown in FIG. 2. FIG. 10 is a flowchart showing an operation example of the regeneration state determination unit 105 shown in FIG. 2.

[0021] The control device 100 shown in Fig. 2 can be configured using a computer such as a microcomputer and peripheral circuits and devices of the computer, and has a plurality of blocks shown in Fig. 2 as a functional configuration configured by a combination of hardware such as the computer and software such as a program executed by the computer. In the example shown in Fig. 2, the control device 100 includes a fuel injection control unit 101, a forced regeneration start determination unit 102, a forced regeneration control unit 103, a regeneration target temperature reset unit 104, and a regeneration state determination unit 105. The control device 100 has a function of acquiring the number of revolutions (rotation speed) of the engine 1 based on the output of a revolution speed sensor (not shown), and estimating the amount of soot accumulation in the DPF device 5 based on the operating state, etc.

[0022] The fuel injection control unit 101, for example, controls a fuel injection device (not shown) of the engine 1 according to an instruction from the forced regeneration control unit 103, and performs, for example, post injection during forced regeneration.

[0023] The forced regeneration start determination unit 102 requests the start of forced regeneration when the pressure difference of the DPF 52 detected by the pressure sensors 96 and 97 exceeds a predetermined threshold value. In this embodiment, the state in which the start of forced regeneration is requested by this forced regeneration start determination unit 102 is defined as a state in which regeneration is requested. The state in which regeneration is requested is set to a state in which no regeneration is requested when, for example, the regeneration state determination unit 105 determines that regeneration is completed or determines that regeneration cannot be completed and should be terminated.

[0024] When there is a regeneration request, the forced regeneration control unit 103 performs temperature control during forced regeneration as follows. That is, the forced regeneration control unit 103 performs temperature control by feeding back the DOC outlet temperature, for example by controlling the post injection of the engine 1 and controlling the HC dosing amount by the HC doser 7, so that the DOC outlet temperature matches a predetermined regeneration target temperature calculated successively, for example, as shown in Fig. 3. However, HC is not dosed (injected) until the DOC inlet temperature reaches a temperature (light-off temperature, for example, about 250°C) at which the catalyst contained in the DOC 51 is activated.

[0025] Fig. 3 shows a schematic diagram of the change in the regeneration target temperature, with the horizontal axis representing time and the vertical axis representing the DOC outlet temperature. In the example shown in Fig. 3, the forced regeneration control unit 103 changes the regeneration target temperature by dividing the regeneration state into the following five stages. In the example shown in Fig. 3, it is assumed that there is a regeneration request at time t11 (there is no regeneration state until time t11). There are five regeneration states: (1) before regeneration starts (regeneration state: none), (2) ToWarmUp state until the WarmUp Target temperature (approximately 350°C) is reached, (3) WarmUp state after the WarmUp Target temperature has been reached, (4) ToTarget state before the Target temperature (approximately 500°C, final target temperature) is reached, and (5) Target state after the Target temperature has been reached.

[0026] The ToWarmUp state is a regeneration state in which the maximum value of the regeneration target temperature is the WarmUp Target temperature (e.g., 350°C). In the ToWarmUp state, the regeneration target temperature is calculated so that the actual DOC outlet temperature at time t11 when forced regeneration is started is set as the initial value and increases to the WarmUp Target temperature by time t12, a predetermined time later. The regeneration state from time t11 to time t12 is the ToWarmUp state.

[0027] The WarmUp state is a regeneration state in which the regeneration target temperature is constant at the WarmUp Target temperature (e.g., 350°C). The regeneration state from time t12 to time t13, a predetermined time later, is the WarmUp state. In the following, the ToWarmUp state and the WarmUp state may be collectively referred to as the WarmUp state. The time from time t11 to time t13 is, for example, about 2 minutes for one temperature rise.

[0028] Moreover, the ToTarget state is a regeneration state in which the maximum value of the regeneration target temperature is the Target temperature -50°C (e.g., 450°C). In the ToTarget state, the regeneration target temperature is calculated so that the WarmUp Target temperature (e.g., 350°C) is set as the initial value and increases to the Target temperature -50°C by time t14, a predetermined time later. The regeneration state from time t13 to time t14 is the ToTarget state.

[0029] The target state is a regeneration state in which the maximum value of the regeneration target temperature is the target temperature (e.g., 500°C). In the target state, the regeneration target temperature is calculated so that the target temperature increases from an initial value of -50°C (e.g., 450°C) to the target temperature (e.g., 500°C) at a predetermined rate and remains constant after it has increased to the target temperature. The regeneration state after time t14 is the target state.

[0030] FIG. 4 shows an example of temperature control, with the horizontal axis representing time and the vertical axis representing the DOC inlet temperature, DOC outlet temperature, or HC dosing amount. In the example shown in FIG. 4, it is assumed that there is a regeneration request at time t1. Forced regeneration starts at time t1, and the DOC inlet temperature and DOC outlet temperature rise, for example, by post-injection control. Then, at time t2, when the DOC inlet temperature reaches the HC dosing start temperature (for example, the light-off temperature or a temperature with a certain margin above the light-off temperature), HC dosing starts. After that, the DOC outlet temperature is feedback-controlled to be the final value (target temperature) of the regeneration target temperature in the target state. Then, when regeneration is completed at time t3, forced regeneration ends and HC dosing stops. Note that dt1 corresponds to the increase in engine exhaust temperature, and dt2 corresponds to the increase in temperature due to combustion in the DOC 51 by fuel supply.

[0031] Next, the regeneration target temperature reset unit 104 shown in Fig. 2 will be described. The regeneration target temperature reset unit 104 has a function of resetting the regeneration target temperature to the regeneration target temperature in the ToWarmUp state or the WarmUp state under certain conditions. When forced regeneration starts and the regeneration state is the ToTarget state or the Target state, when the regeneration target temperature - the DOC outlet temperature becomes, for example, 200°C or higher, the regeneration target temperature reset unit 104 resets the regeneration state by the forced regeneration control unit 103 to the ToWarmUp state or the WarmUp state so that the DOC outlet temperature does not become excessive due to extreme feedback. Note that an operation example will be described below using the case where the condition is "regeneration target temperature - DOC outlet temperature is 200°C or higher" as an example.

[0032] FIG. 5 shows an example of the operation of the regeneration target temperature reset unit 104. The process shown in FIG. 5 is executed when there is a regeneration request. When the process shown in FIG. 5 is started, the regeneration target temperature reset unit 104 first acquires the regeneration target temperature, the DOC outlet temperature, and the regeneration state (step S101). Next, the regeneration target temperature reset unit 104 judges whether or not forced regeneration is in progress (step S102). If forced regeneration is in progress (if "Y" in step S102), the regeneration target temperature reset unit 104 judges whether or not the regeneration state is the ToTarget state or the Target state (step S103). If the regeneration state is the ToTarget state or the Target state (if "Y" in step S103), the regeneration target temperature reset unit 104 judges whether or not the time during which the regeneration target temperature - the DOC outlet temperature > 200°C is a certain time or more (step S104).

[0033] When the time during which the regeneration target temperature-DOC outlet temperature>200°C, which is the judgment condition in step S104, is longer than a certain time, it can be set to correspond to the case where the exhaust temperature (DOC 51 inlet temperature) is estimated to be lower than the light-off temperature for longer than a certain time. As for the temperature condition, since the maximum value of the regeneration target temperature is the final target value in the target state (target temperature=500°C, for example), in this example, it is the case where the DOC outlet temperature is <300°C. As for the time condition, by appropriately setting a certain time, it is possible to correspond to the case where the exhaust temperature (DOC 51 inlet temperature) is estimated to be lower than the light-off temperature for longer than a certain time. The certain time is, for example, about several tens of seconds to several minutes.

[0034] If the time during which regeneration target temperature-DOC outlet temperature>200°C is equal to or longer than a certain time ("Y" in step S104), the regeneration target temperature reset unit 104 resets the regeneration target temperature, instructs the forced regeneration control unit 103 to restart the regeneration state from the WarmUp state (ToWarmUp state or WarmUp state), and increments the temperature rise reset count by 1 (step S105). The temperature rise reset count represents the number of times the regeneration state was reset from the ToTarget state or Target state to the ToWarmUp state or WarmUp state (the number of times the DOC outlet temperature was restarted from a temperature at which the DOC inlet temperature is estimated to be below the light-off temperature to a temperature at which the DOC inlet temperature is estimated to be above the light-off temperature) during the period from when a regeneration request was generated to when forced regeneration was completed.

[0035] On the other hand, if the regeneration state is not the ToTarget state and not the Target state (if "N" in step S103), or if the time during which the regeneration target temperature - the DOC outlet temperature > 200°C is not longer than a certain period of time (if "N" in step S104), the regeneration target temperature reset unit 104 executes the processing from step S101 onwards again.

[0036] On the other hand, if forced regeneration is not in progress (if forced regeneration has ended) (if "N" in step S103), the regeneration target temperature reset unit 104 initializes the temperature rise reset count to 0 (step S106) and ends the processing shown in FIG. 5.

[0037] Next, the regeneration state determination unit 105 shown in Fig. 2 will be described. When the DOC outlet temperature cannot reach the Target temperature during forced regeneration, the regeneration state determination unit 105 determines the state of temperature control and notifies the user of the determination result, cause, countermeasures, etc. In this embodiment, cases when the DOC outlet temperature cannot reach the Target temperature during forced regeneration are classified into three cases: inefficient regeneration (1), inefficient regeneration (2), and incomplete regeneration.

[0038] Inefficient regeneration (1): The exhaust temperature (DOC inlet temperature) reaches the light-off temperature, but because the catalyst in DOC 51 has deteriorated, HC is not burned in DOC 51 and the DOC outlet temperature does not reach the target temperature (for example, 500°C).

[0039] Inefficient regeneration (2): Due to driving conditions, etc., the DOC inlet temperature frequently rises and falls above the light-off temperature, causing HC injection to be stopped frequently and the DOC outlet temperature to not reach the target temperature.

[0040] Regeneration incomplete: Due to engine failure or other reasons, the exhaust temperature does not reach the light-off temperature (250°C), making it impossible to inject HC and causing the DOC outlet temperature to not reach the target temperature.

[0041] In order to distinguish between the above cases, the regeneration state determination unit 105 performs calculations including the DOC inlet temperature, the DOC outlet temperature, the regeneration state, and the number of resets of the regeneration target temperature as shown in Fig. 6 to determine the failure state and the like in more detail. The regeneration state determination unit 105 also notifies a predetermined notification destination of, for example, a failure code as information indicating the determination result, or notifies information indicating a warning to the user. Here, the predetermined notification destination is, for example, an external server that remotely manages the operating state of the engine control system 10, an external notification destination registered in advance on a WEB system, or the like. The regeneration state determination unit 105 may also notify the user of certain information based on the determination result using the monitor 8.

[0042] An example of the operation of the regeneration state determination unit 105 will be described with reference to Fig. 7. The process shown in Fig. 7 is executed when there is a regeneration request. When the process shown in Fig. 7 starts, the regeneration state determination unit 105 first acquires the DOC inlet temperature, the DOC outlet temperature, and the number of temperature rise resets (step S201). Next, the regeneration state determination unit 105 determines whether or not the time since the regeneration was requested is two hours or more (step S202). In this case, two hours is an example of a second determination time that is longer than the first determination time.

[0043] If the time since the regeneration was requested is more than two hours ("Y" in step S202), the regeneration status determination unit 105 determines that the regeneration is incomplete and issues a notice that regeneration will not start due to an engine failure (step S210), and then requests stationary manual regeneration (step S211). In step S211, for example, the unit waits for a certain period of time for a response to the request for stationary manual regeneration, and if there is no response and no increase in the DOC outlet temperature, a warning is issued and the process shown in FIG. 7 is terminated.

[0044] On the other hand, if the time since the regeneration was requested is less than 2 hours (if "N" in step S202), the regeneration state determination unit 105 determines whether the number of times regeneration has been restarted from the WarmUp state is X times or more (X is any natural number) based on the number of times of temperature rise reset (step S203). If the number of times regeneration has been restarted from the WarmUp state is X times or more (if "Y" in step S203), the regeneration state determination unit 105 determines that this is the case of inefficient regeneration (2) and issues a notice such as a warning (step S207), and determines whether the regeneration completion condition has been reached (step S205). The regeneration completion condition is, for example, when the PM accumulation amount estimated from the temperature change of the regeneration control, etc., using the estimated value of the PM accumulation amount estimated from the pressure difference as the initial value is equal to or less than a predetermined threshold value, when the time during which the DOC outlet temperature reaches the target temperature -50°C is equal to or more than a predetermined threshold value, etc. If the regeneration completion condition is met ("Y" in step S205), the regeneration state determination unit 105 ends the forced regeneration (sets "regeneration request present" to "not present") (step S206), and ends the process shown in Fig. 7. On the other hand, if the regeneration completion condition is not met ("N" in step S205), the regeneration state determination unit 105 executes the process from step S201 onwards again.

[0045] On the other hand, if the number of times regeneration has been restarted from WarmUp is less than X times ("N" in step S203), the regeneration state determination unit 105 determines whether the time during which the DOC outlet temperature is equal to or lower than the target temperature -50°C during HC dosing is equal to or greater than one hour (step S204). Here, "during HC dosing" means that the DOC inlet temperature continues to reach the HC dosing start temperature (for example, the light-off temperature or a temperature with a certain margin above the light-off temperature). In this case, one hour is an example of the first determination time.

[0046] If the time during HC dosing during which the DOC outlet temperature is equal to or lower than the target temperature −50° C. is one hour or more (if “Y” in step S204), the regeneration state determination unit 105 determines that this is the case of inefficient regeneration (1) and issues a notice to the effect that there is a possibility of a malfunction of the DOC 51 (step S208), then requests stationary manual regeneration (step S209), terminates forced regeneration (sets “regeneration requested” to “not requested”) (step S206), and terminates the process shown in FIG. 7.

[0047] On the other hand, if the time during HC dosing during which the DOC outlet temperature is equal to or lower than the target temperature -50°C is not equal to or lower than one hour (if "N" in step S204), the regeneration state determination unit 105 determines whether or not the regeneration completion condition is reached (step S205). If the regeneration completion condition is reached (if "Y" in step S205), the regeneration state determination unit 105 ends the forced regeneration (sets "regeneration request present" to "not present") (step S206), and ends the processing shown in Fig. 7. On the other hand, if the regeneration completion condition is not reached (if "N" in step S205), the regeneration state determination unit 105 executes the processing from step S201 onwards again.

[0048] The judgment conditions, judgment results, and measures to be taken by the playback state judgment unit 105 are shown in FIG.

[0049] In the case of inefficient regeneration (1), the judgment condition is that the time during HC dosing during which the DOC outlet temperature is equal to or lower than the target temperature -50°C is 1 hour or more. The state of the engine 1 is no problem. The state of the DPF device 5 is that the DOC 51 may be deteriorated. The operating state of the vehicle equipped with the engine 1 is no problem. The countermeasure is to request stationary manual regeneration. If the problem is not resolved even after stationary manual regeneration, troubleshooting related to the DPF device 5 is performed. Examples of troubleshooting include measuring the DOC efficiency and performing DOC drying operation. The DOC efficiency can be calculated using the formula (amount of heat converted by the DOC / amount of heat of HC injected for regeneration) * 100. The DOC drying operation is an operation that removes unburned fuel and soot attached to the DOC inlet by controlling the engine exhaust temperature rise + not injecting HC for regeneration.

[0050] In the case of inefficient regeneration (2), the judgment condition is that regeneration has been restarted from the WarmUp state X times or more. The state of the engine 1 and the state of the DPF device 5 are fine. The vehicle operating state is that the load fluctuation is large, and the DOC inlet temperature is frequently below 250°C. The countermeasure is to recommend stationary manual regeneration or to issue a warning that the vehicle operating state is in a state where the load fluctuation is large (for example, to issue a notice such as a recommendation to change the vehicle operating state to a state where the load fluctuation is small).

[0051] If regeneration is not complete, the judgment condition is that the time since regeneration was requested is two hours or more. The engine state is a state in which a failure has occurred or a state in which the engine has been left in a low idle state (an idling state at the minimum rotation speed at which the engine does not stop). If the engine is left in a low idle state, the light-off temperature may not be reached as a result, and forced regeneration may not be able to start. However, the cause can be identified, for example, by checking the operating state (time left unattended, etc.) at the destination of the judgment result by the regeneration state judgment unit 105. There are no problems with the state of the DPF device 5 and the operating state of the vehicle. The countermeasure is to request stationary manual regeneration. If the problem is not resolved by stationary manual regeneration, engine troubleshooting (VGT (variable geometry turbo) failure, air leakage, etc.) should be performed.

[0052] Next, referring to Fig. 9, the change in the HC dosing state in the cases of inefficient regeneration (1), inefficient regeneration (2), and incomplete regeneration will be described. Fig. 9, with time on the horizontal axis, shows, from top to bottom, the HC dosing state (under execution (control) or stopped) in the cases of inefficient regeneration (1), inefficient regeneration (2), and incomplete regeneration. Note that Fig. 9 shows the state where forced regeneration is requested at time t21, one hour has passed since time t21 at time t22, and two hours have passed since time t21 at time t23.

[0053] In the case of inefficient regeneration (1), the exhaust temperature continues to reach the light-off temperature, and HC dosing continues to be performed. In the case of inefficient regeneration (2), the exhaust temperature continues to reach the light-off temperature, and HC dosing continues to be performed. In the case of incomplete regeneration, the exhaust temperature does not continue to reach the light-off temperature, and HC dosing is stopped continuously. However, in this example, in the case of incomplete regeneration, the exhaust temperature reaches the light-off temperature before time T20 of time t23, and HC dosing is performed before time T20 of time t23, but the regeneration completion condition is not satisfied before time t23 is reached.

[0054] Next, referring to Fig. 10, an example of the operation of the regeneration state determination unit 105 when forced regeneration is interrupted or suspended will be described. The process shown in Fig. 10 is executed when there is a regeneration request. When the process shown in Fig. 10 is started, the regeneration state determination unit 105 first acquires estimated values ​​of the DOC outlet temperature, engine speed, and soot accumulation amount (step S301). Next, the regeneration state determination unit 105 determines whether or not a regeneration stop condition is met (step S302). The regeneration stop condition is, for example, engine stop (interrupted) due to key-off, or regeneration prohibition (interruption) by the user, etc.

[0055] If the playback stop condition is met ("Y" in step S302), the playback state determination unit 105 repeatedly executes the processes in steps S301 and S302 until the playback stop condition is no longer met.

[0056] On the other hand, if the regeneration stop condition is not met ("N" in step S302), the regeneration state judgment unit 105 instructs the forced regeneration control unit 103 to execute forced regeneration (step S303), and judges whether or not the regeneration completion condition is met (step S304). If the regeneration completion condition is met ("Y" in step S304), the regeneration state judgment unit 105 ends the forced regeneration (sets "regeneration request present" to "not present") (step S305), and ends the process shown in Fig. 10. On the other hand, if the regeneration completion condition is not met ("N" in step S304), the regeneration state judgment unit 105 executes the process from step S301 onwards again.

[0057] (Action and effect) As described above, according to this embodiment, the control device 100 has a DPF 52 (filter) that collects particulate matter in the exhaust gas of the engine 1, and a DOC 51 (oxidation catalyst) provided upstream of the DPF 52, and in a DPF device 5 (exhaust gas aftertreatment device) that regenerates the DPF 52 by the action of the DOC 51, when forced regeneration is being performed to forcibly raise the temperature of the exhaust gas, when the number of times that the exhaust gas temperature is estimated to have fallen below the light-off temperature for a predetermined period of time or more exceeds a predetermined threshold value (X times), the control device 100 is provided with a regeneration state determination unit 105 that notifies the user that there is a problem with the operating state of the engine 1. With this configuration, it is possible to notify the user that there is a problem with the operating state during forced regeneration.

[0058] Furthermore, if the regeneration status determination unit 105 determines that the forced regeneration is not completed even after the time during which the exhaust temperature is estimated to be above the light-off temperature has elapsed for more than a first determination time (one hour), the regeneration status determination unit 105 can be configured to notify that there is a possibility of a malfunction of the DOC 51 (oxidation catalyst).

[0059] Furthermore, if the regeneration state determination unit 105 determines that the forced regeneration has not been completed even after a second determination time (2 hours) that is longer than the first determination time has elapsed since the start of the forced regeneration, it can be configured to notify the user that there is a possibility of engine failure.

[0060] Although the embodiment of the present invention has been described above with reference to the drawings, the specific configuration is not limited to the above embodiment, and design changes and the like are also included within the scope of the gist of the present invention. For example, in the above embodiment, the exhaust gas aftertreatment device is configured with the DPF device 5, but, for example, an SCR device (Selective Catalytic Reduction device) may be provided further downstream, or, for example, an SCR device may be provided downstream and the DPF 52 may be omitted from the DPF device 5. In addition, a part or all of the program executed by the control device 100 may be distributed via a computer-readable recording medium or a communication line. [Explanation of symbols]

[0061] 1... engine, 3... exhaust pipe, 5... DPF device, 7... HC dozer, 51... DOC, 52... DPF, 94... DOC inlet temperature sensor, 95... DOC outlet temperature sensor, 96, 97... pressure sensor, 100... control device, 105... regeneration state determination unit

Claims

1. In an exhaust gas aftertreatment device having a filter that traps particulate matter in the exhaust gas of an engine and an oxidation catalyst provided upstream of the filter, the filter being regenerated by the action of the oxidation catalyst, when forced regeneration is being performed to forcibly increase the temperature of the exhaust gas, when the number of times that the exhaust temperature is estimated to be below the light-off temperature for a predetermined period of time or more exceeds a predetermined threshold value; a regeneration state determination unit that notifies the engine of a problem in its operating state; A control device is provided.

2. The regeneration state determination unit further notifies the user that there is a possibility of a failure of the oxidation catalyst when it determines that the forced regeneration is not completed even if the time during which the exhaust temperature is estimated to be equal to or higher than the light-off temperature has elapsed for a first determination time or more. The control device according to claim 1 .

3. The regeneration state determination unit further notifies the user that there is a possibility of a malfunction of the engine when it determines that the forced regeneration has not been completed even after a second determination time, which is longer than the first determination time, has elapsed since the start of the forced regeneration. The control device according to claim 2.

4. In an exhaust gas aftertreatment device having a filter that traps particulate matter in the exhaust gas of an engine and an oxidation catalyst provided upstream of the filter, the filter being regenerated by the action of the oxidation catalyst, when forced regeneration is being performed to forcibly increase the temperature of the exhaust gas, when the number of times that the exhaust temperature is estimated to be below the light-off temperature for a predetermined period of time or more exceeds a predetermined threshold value; The step of notifying Notification methods, including:

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