JP5517253B2 - engine - Google Patents

Description

  The present invention relates to an engine, and in particular, a particulate filter that collects particulate matter contained in exhaust gas, and a differential pressure sensor that detects a differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter. The differential pressure sensor is connected, and the particulate matter accumulation amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor, and the estimated particulate matter accumulation amount is stored in the storage unit. And a controller that determines whether to regenerate the particulate filter based on the estimated particulate matter accumulation amount.

  In an engine such as a diesel engine, a diesel particulate filter (hereinafter referred to as “DPF”) that collects particulate matter (hereinafter referred to as “PM”) contained in exhaust gas is collected by PM. When clogged, the oxidation reaction of PM decreases. Therefore, in order to maintain the oxidation reaction of PM in the DPF, the PM deposition amount of the DPF is estimated based on the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the DPF, and the estimated PM deposition amount is a predetermined standard. A technique is known in which the DPF is forcibly regenerated by post-injecting fuel when the deposition amount is exceeded (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-332065

  However, in the above-described technique, when the differential pressure is reduced due to the change over time of the differential pressure while the engine is stopped after the engine is started, if the PM deposition amount is estimated based on the reduced differential pressure, the actual PM deposition As a result, the estimated PM deposition amount becomes smaller than the actual PM deposition amount, and the actual PM deposition amount is underestimated. In particular, when the engine is started after a long time has passed since the engine was stopped, the pressure drop after the engine is started is further reduced.

  Therefore, there has been a problem that the amount of accumulated PM in the DPF cannot be accurately estimated, and the forced regeneration of the DPF cannot be performed at an appropriate time. If the forced regeneration of the DPF cannot be performed at an appropriate time, there is a possibility that the DPF may be melted, so-called runaway regeneration.

  The present invention has been made in view of the above situation, and provides an engine that can accurately estimate the amount of PM accumulated in the DPF and perform the forced regeneration of the DPF at an appropriate time.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, a particulate filter that collects particulate matter contained in exhaust gas, and a differential pressure sensor that detects a differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter; The differential pressure sensor is connected, and the particulate matter accumulation amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor, and the estimated particulate matter accumulation amount is stored in the storage unit. A controller for determining whether or not to forcibly regenerate the particulate filter based on the estimated particulate matter accumulation amount, wherein the controller includes the particulate matter accumulation amount after engine startup And the calculated increase in the amount of particulate matter accumulated after the engine is started is stored in the storage unit. Accumulate the previous particulate matter accumulation amount, determine whether the accumulated particulate matter accumulation amount exceeds a predetermined reference deposition amount, and the accumulated particulate matter accumulation amount is When the reference deposition amount is exceeded, the particulate filter is forcibly regenerated.

  In claim 2, the particulate filter which collects the particulate matter contained in the exhaust gas, the differential pressure sensor which detects the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter, A differential pressure sensor is connected, and the particulate matter accumulation amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor; the estimated particulate matter accumulation amount is stored in a storage unit; A controller for determining whether or not to regenerate the particulate filter based on the estimated amount of accumulated particulate matter, and whether or not the controller has completed the warm-up operation after starting the engine. And when it is determined that the warm-up operation has been completed, an increase in the amount of particulate matter accumulated after the completion of the warm-up operation is calculated, and the calculated warm-up operation is calculated. The amount of increase in the amount of accumulated particulate matter after completion is added to the amount of accumulated particulate matter before starting the engine stored in the storage unit, and the amount of accumulated particulate matter determined by the integration is a predetermined standard. It is determined whether or not the accumulated amount is exceeded, and when the accumulated particulate matter accumulated amount exceeds the reference accumulated amount, the particulate filter is forcibly regenerated.

  In claim 3, the particulate filter which collects the particulate matter contained in the exhaust gas, the differential pressure sensor which detects the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter, A differential pressure sensor is connected, and the particulate matter accumulation amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor; the estimated particulate matter accumulation amount is stored in a storage unit; A controller for determining whether or not to regenerate the particulate filter based on the estimated amount of accumulated particulate matter, and whether or not the controller has completed the warm-up operation after starting the engine. And measure the elapsed time after forcibly regenerating the particulate filter, and the measured elapsed time is set to a predetermined reference time. If the warm-up operation is completed, and it is determined that the measured elapsed time has passed the reference time, particulate matter deposition after the completion of the warm-up operation is determined. The amount of increase in the amount is calculated, and the amount of increase in the amount of accumulated particulate matter after completion of the warm-up operation is added to the amount of particulate matter accumulated before starting the engine stored in the storage unit, It is determined whether or not the accumulated particulate matter deposition amount exceeds a predetermined reference deposition amount, and when the particulate matter deposition amount obtained by integration exceeds the reference deposition amount, the particulate filter Is forcibly regenerated.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, an error from the actual particulate matter accumulation amount is reduced by integrating the amount of increase in the particulate matter deposition amount after the engine start to the particulate matter deposition amount before the engine start. Therefore, the particulate matter accumulation amount of the particulate filter can be accurately estimated, and the forced regeneration of the particulate filter can be performed at an appropriate time.

  According to the second aspect of the present invention, the error from the actual particulate matter accumulation amount is reduced by integrating the amount of the particulate matter accumulation amount after the warm-up operation is added to the particulate matter accumulation amount before starting the engine. . After the warm-up operation is completed, the reduced differential pressure is expected to recover, so the increase in the particulate matter deposition amount calculated based on the differential pressure after the warm-up operation is completed is the increase in the actual particulate matter deposition amount. Matches minute and accuracy. Therefore, the particulate matter accumulation amount of the particulate filter can be accurately estimated, and the forced regeneration of the particulate filter can be performed at an appropriate time.

  According to a third aspect of the present invention, the error from the actual particulate matter accumulation amount is reduced by integrating the particulate matter accumulation amount before starting the engine by the increment of the particulate matter accumulation amount after the completion of the warm-up operation. . After the warm-up operation is completed, the reduced differential pressure is expected to recover, so the increase in the particulate matter deposition amount calculated based on the differential pressure after the warm-up operation is completed is the increase in the actual particulate matter deposition amount. Matches minute and accuracy. Also, only when the time has passed since the previous forced regeneration, the previous forced regeneration is performed in the near future by determining whether forced regeneration is necessary based on the accumulated particulate matter accumulation amount. Until then, excessive forced regeneration will not occur. Therefore, the particulate matter accumulation amount of the particulate filter can be accurately estimated, and the forced regeneration of the particulate filter can be performed at an appropriate time.

1 is a block diagram showing an overall configuration of an engine according to a first embodiment of the present invention. The flowchart which shows the control procedure of the forced regeneration of DPF which concerns on 1st embodiment of this invention. The figure which shows the relationship between PM deposition amount and engine operation time which concern on 1st embodiment of this invention. The flowchart which shows the control procedure of the forced regeneration of DPF which concerns on 2nd embodiment of this invention. The figure which shows the relationship between PM accumulation amount and engine operation time which concern on 2nd embodiment of this invention. The flowchart which shows the control procedure of the forced regeneration of DPF which concerns on 3rd embodiment of this invention.

    Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  First, the overall configuration of the engine 1 according to the first embodiment of the present invention will be described with reference to FIG.

  The engine 1 includes an engine body 2 such as an in-line four-cylinder diesel engine, a common rail fuel injection device 3 as a fuel injection device, an exhaust gas recirculation (hereinafter referred to as “EGR”) device 4, an exhaust turbine excess It comprises a supercharger 5 such as a turbocharger, an exhaust purification device 6 and the like.

  In the engine body 2, the cylinder head 21 is fixed to the upper surface of the cylinder block 22. A crankshaft 24 is rotatably supported on the cylinder block 22, and four cylinders 23, 23... Are formed at equal intervals along the axial direction of the crankshaft 24. An intake pipe 25 is connected to one side of the cylinder head 21 in the direction orthogonal to the crankshaft 24 via an intake manifold (not shown), and an exhaust (not shown) is connected to the other side of the cylinder head 21. An exhaust pipe 26 is connected through the manifold.

  The common rail fuel injection device 3 is a supply pump (not shown) for increasing the pressure of the fuel, the common rail 31 for storing the fuel that has been increased in pressure by the supply pump, and the high pressure fuel in the common rail 31 is injected into the cylinders 23, 23. It consists of injectors 32, 32... Of these, the injectors 32, 32,... Are connected to the controller 7, and fuel is injected from the injectors 32, 32,.

  The EGR device 4 includes an EGR pipe 41 through which exhaust gas recirculated to intake air flows, an EGR cooler 42 that cools the exhaust gas in the EGR pipe 41, an EGR valve 43 that opens and closes the EGR pipe 41, and the like. Among these, the EGR valve 43 and the controller 7 are connected, and the EGR valve 43 is opened and closed with a predetermined opening degree by a signal from the controller 7. As a result, an amount of exhaust gas corresponding to the opening of the EGR valve 43 is sent into the combustion chamber (not shown) of the engine body 2 by the EGR pipe 41, and the combustion temperature in the combustion chamber is lowered by the low oxygen atmosphere. The amount of NOx generated by high temperature combustion can be reduced.

  In the supercharger 5, a rotary shaft 52 is rotatably supported in a housing 51 communicating with the intake pipe 25 and the exhaust pipe 26, and a turbine 53 is fixed to the exhaust pipe 26 side on the rotary shaft 52. On the other hand, a compressor 54 is fixed to the intake pipe 25 side on the rotation shaft 52. Thus, when the turbine 53 is rotated by the energy of the exhaust gas flowing in the exhaust pipe 26, the intake air is compressed by the compressor 54 that rotates together with the turbine 53 via the rotating shaft 52, and the compressed intake air is compressed into the cylinders 23, 23,. By being sent in, the intake charge efficiency in the cylinders 23, 23... Is improved, and the output of the engine 1 can be increased.

  The exhaust purification device 6 is composed of an oxidation catalyst carrier (Diesel Oxidation Catalyst; hereinafter referred to as “DOC”) 61, for example, a wall flow type DPF 62 or the like, and is provided on the exhaust outlet side of the exhaust pipe 26. As a result, carbon monoxide (CO), hydrocarbon (HC), and organic soluble component (SOF) contained in the exhaust gas are oxidized by the DOC 61, and PM contained in the exhaust gas is collected and oxidized by the DPF 62. Thus, the exhaust gas can be purified.

  Further, the exhaust purification device 6 is provided with a differential pressure sensor 63 configured by an upstream sensor 631 provided on the exhaust gas upstream side of the DOC 61 and a downstream sensor 632 provided on the exhaust gas downstream side of the DPF 62. The differential pressure sensor 63 and the controller 7 are connected, and the difference between the pressure detected by the upstream sensor 631 and the pressure detected by the downstream sensor 632 is the exhaust gas upstream side of the DPF 62 and the exhaust gas downstream side. Is input to the controller 7 as a differential pressure with respect to the side.

  The controller 7 includes a central processing unit (not shown), a storage unit 71, and the like. In the controller 7, the PM accumulation amount of the DPF 62 is estimated based on the differential pressure detected by the differential pressure sensor 63, and the estimated PM accumulation amount is stored in the storage unit 71. An elapsed time (hereinafter referred to as “elapsed time after start”) Ts after the engine is started is measured by a counter (not shown) of the controller 7. In addition, the storage unit 71 stores a reference accumulation amount Sc as a reference value for the estimated PM accumulation amount, a reference post-start elapsed time Tsc as a reference value for the post-start elapsed time Ts, and forced regeneration of the DPF 62 described later. A control program and the like are stored.

  Next, the forced regeneration control procedure of the DPF 62 will be described with reference to FIGS.

  As shown in FIG. 2, when the engine 1 is started (step S1, YES), an increase in PM accumulation after the engine is started (hereinafter referred to as “increase in PM accumulation after start”) ΔS1 is calculated. (Step S2).

  Specifically, in FIG. 3, the vertical axis is the estimated PM accumulation amount, the horizontal axis is the engine operation time, the PM accumulation amount at the engine start time T0 is Sa0, and the PM accumulation amount at the post-start elapsed time Ts is Sa1. The post-startup PM accumulation amount increase ΔS1 is a value obtained by subtracting Sa0 from Sa1 (Sa1-Sa0).

  Then, returning to FIG. 2, the post-startup PM accumulation amount increase ΔS1 is integrated with the PM accumulation amount Sb before engine start stored in the storage unit 71 (step S3), and the PM accumulation amount obtained by integration is obtained. It is determined whether or not Sb + ΔS1 exceeds the reference accumulation amount Sc (step S4).

  If the accumulated PM amount Sb + ΔS1 exceeds the reference accumulation amount Sc (step S4, YES), the DPF 62 is forcibly regenerated (step S5). That is, the fuel is post-injected from the injectors 32, 32.

  On the other hand, if the accumulated PM amount Sb + ΔS1 is less than or equal to the reference accumulation amount Sc (step S4, NO), the procedure after step S2 is repeated without forcibly regenerating the DPF 62.

  As described above, the DPF 62 as a particulate filter that collects PM contained in the exhaust gas, the differential pressure sensor 63 that detects the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the DPF 62, and the differential pressure sensor 63 is connected, the PM accumulation amount of the DPF 62 is estimated based on the differential pressure detected by the differential pressure sensor 63, the estimated PM accumulation amount is stored in the storage unit 71, and based on the estimated PM accumulation amount In the engine 1 including the controller 7 for determining whether to forcibly regenerate the DPF 62, the controller 7 calculates a post-starting PM accumulation amount increase ΔS1 as an increase in the PM accumulation amount after the engine is started. Then, the calculated post-startup PM accumulation amount increase ΔS1 is integrated with the PM accumulation amount Sb before engine startup stored in the storage unit 71, and the PM accumulation amount obtained by integration is calculated. It is determined whether or not Sb + ΔS1 exceeds the reference deposition amount Sc, and the DPF 62 is forcibly regenerated when the accumulated PM deposition amount Sb + ΔS1 exceeds the reference deposition amount Sc.

  With such a configuration, an error from the actual PM accumulation amount is reduced by integrating the PM accumulation amount increase ΔS1 after starting to the PM accumulation amount Sb before starting the engine. Therefore, it is possible to accurately estimate the amount of PM accumulated in the DPF 62 and perform the forced regeneration of the DPF 62 at an appropriate time.

  Next, an engine according to a second embodiment of the present invention will be described with reference to FIGS. In addition, since the member of the same code | symbol as 1st embodiment is the same structure as 1st embodiment, detailed description is abbreviate | omitted.

  In the engine according to the second embodiment, as shown in FIG. 4, when the engine 1 is started (step S21, YES), a time count of the elapsed time Ts after starting is started by the timer of the controller 7 (step S22). Then, it is determined whether or not the elapsed time Ts after the start has passed the reference elapsed time Tsc, that is, whether or not the warm-up operation has been completed (step S23).

  If the elapsed time Ts after the start has passed the elapsed time Tsc after the reference start (step S23, YES), it is determined that the warm-up operation has been completed, and the PM accumulation amount after the completion of the warm-up operation is continued. ΔS2 is calculated (hereinafter referred to as “increase in PM deposition amount after warm-up”) ΔS2 (step S24).

  Specifically, in FIG. 5, the vertical axis represents the estimated PM accumulation amount, the horizontal axis represents the engine operation time, the PM accumulation amount at the reference start elapsed time Tsc Sa2, and the PM accumulation amount at the after start start elapsed time Ts Sa3. Then, the post-warm-up PM accumulation amount increase ΔS2 is a value obtained by subtracting Sa2 from Sa3 (Sa3-Sa2).

  Then, returning to FIG. 4, the PM accumulation amount Sb before warming-up stored in the storage unit 71 is accumulated with the PM accumulation amount increase ΔS2 after warming up (step S25), and the PM accumulation obtained by the accumulation is obtained. It is determined whether or not the amount Sb + ΔS2 exceeds the reference deposition amount Sc (step S26).

  If the accumulated PM amount Sb + ΔS2 is greater than the reference accumulation amount Sc (step S26, YES), the DPF 62 is forcibly regenerated (step S27). That is, the fuel is post-injected from the injectors 32, 32.

  On the other hand, if the accumulated PM amount Sb + ΔS2 is equal to or less than the reference accumulation amount Sc (step S26, NO), the DPF 62 is not forcibly regenerated, and the steps after step S24 are repeated.

  In step S23, if the elapsed time Ts after start has not passed the elapsed time Tsc after reference start (step S23, NO), it is determined that the warm-up operation has not been completed, and the elapsed time Ts after start is equal to The procedure after step S22 is repeated until the elapsed time Tsc after the reference start elapses.

  As described above, the DPF 62 as a particulate filter that collects PM contained in the exhaust gas, the differential pressure sensor 63 that detects the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the DPF 62, and the differential pressure sensor 63 is connected, the PM accumulation amount of the DPF 62 is estimated based on the differential pressure detected by the differential pressure sensor 63, the estimated PM accumulation amount is stored in the storage unit 71, and based on the estimated PM accumulation amount In the engine 1 including the controller 7 that determines whether or not the DPF 62 is forcibly regenerated, the controller 7 determines whether or not the warm-up operation is completed after the engine is started, and the warm-up operation is completed. Is calculated, a post-warm-up PM deposition amount increase ΔS2 is calculated as an increase in the particulate matter deposition amount after completion of the warm-up operation, and the calculated post-warm-up PM deposition amount increase ΔS is calculated. 2 is added to the PM accumulation amount Sb before engine start stored in the storage unit 71, and it is determined whether or not the PM accumulation amount Sb + ΔS2 obtained by the accumulation exceeds the reference accumulation amount Sc, and obtained by accumulation. When the PM accumulation amount Sb + ΔS2 exceeds the reference accumulation amount Sc, the DPF 62 is forcibly regenerated.

  With such a configuration, by integrating the PM accumulation amount increase ΔS2 after warm-up to the PM accumulation amount Sb before starting the engine, an error from the actual PM accumulation amount is reduced. After the warm-up operation is completed, the reduced differential pressure is expected to recover. Therefore, the post-warm-up PM deposition amount increase ΔS2 calculated based on the differential pressure after the warm-up operation is completed is the actual particulate matter deposition amount. Matches the increment accurately. Therefore, it is possible to accurately estimate the amount of PM accumulated in the DPF 62 and perform the forced regeneration of the DPF 62 at an appropriate time.

  In the present embodiment, whether or not the warm-up operation is completed after the engine is started is determined based on the elapsed time Ts after the start, but instead is based on the cooling water temperature of the engine 1. You may make it judge.

  Further, the estimation of the PM accumulation amount from the engine start time T0 to the elapsed time Tsc after the reference start (see FIG. 5), that is, during the warm-up operation period, is to estimate the PM accumulation amount based on the differential pressure. Instead, for example, the PM accumulation amount may be estimated by subtracting the PM combustion amount from the PM emission amount.

  Next, an engine according to a third embodiment of the present invention will be described with reference to FIG. In addition, since the member of the same code | symbol as 1st embodiment is the same structure as 1st embodiment, detailed description is abbreviate | omitted.

  In the engine according to the third embodiment, an elapsed time (hereinafter referred to as “elapsed time after regeneration”) Tr after the DPF 62 is forcibly regenerated is measured by a counter (not shown) of the controller 7. The storage unit 71 stores a reference post-reproduction elapsed time Trc serving as a reference value for the post-reproduction elapsed time Tr.

  As shown in FIG. 6, when the engine 1 is started (step S31, YES), a time count of the post-start elapsed time Ts is started by the timer of the controller 7 (step S32), and the post-start elapsed time Ts is the reference start. It is determined whether or not the elapsed time Tsc has elapsed, that is, whether or not the warm-up operation has been completed (step S33).

  If the elapsed time Ts after start has passed the reference elapsed time Tsc (step S33, YES), it is determined that the warm-up operation has been completed, and the post-regeneration elapsed time Tr continues to be the elapsed time after the reference regeneration. It is determined whether or not the time Trc has elapsed (step S34).

  If the post-regeneration elapsed time Tr has passed the reference post-regeneration elapsed time Trc (YES in step S34), a post-warm-up PM accumulation amount increase ΔS2 is calculated (step S35) (see FIG. 5). .

  Then, the PM accumulated amount increase ΔS2 after warming-up is accumulated to the PM accumulated amount Sb before starting the engine stored in the storage unit 71 (step S36), and the PM accumulated amount Sb + ΔS2 obtained by the accumulation is the reference accumulated amount. It is determined whether or not Sc is exceeded (step S37).

  If the accumulated PM amount Sb + ΔS2 exceeds the reference accumulation amount Sc (step S37, YES), the DPF 62 is forcibly regenerated (step S38). That is, the fuel is post-injected from the injectors 32, 32.

  On the other hand, if the accumulated PM amount Sb + ΔS2 is equal to or less than the reference accumulation amount Sc (step S37, NO), the procedure after step S35 is repeated without the forced regeneration of the DPF 62.

  In step 34, when the post-reproduction elapsed time Tr has not passed the reference post-reproduction elapsed time Trc (NO in step S34), the post-startup elapsed time Ts based on the differential pressure detected by the differential pressure sensor 63. The PM deposition amount Sa3 is estimated (step S39) (see FIG. 5), and it is determined whether the PM deposition amount Sa3 exceeds the reference deposition amount Sc (step S40).

  When the PM deposition amount Sa3 exceeds the reference deposition amount Sc (step S40, YES), the DPF 62 is forcibly regenerated (step S38). That is, the fuel is post-injected from the injectors 32, 32.

  On the other hand, when the PM accumulation amount Sa3 is equal to or less than the reference accumulation amount Sc (step S40, NO), the procedure after step S34 is repeated without performing the forced regeneration of the DPF 62.

  As described above, the DPF 62 as a particulate filter that collects PM contained in the exhaust gas, the differential pressure sensor 63 that detects the differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the DPF 62, and the differential pressure sensor 63 is connected, the PM accumulation amount of the DPF 62 is estimated based on the differential pressure detected by the differential pressure sensor 63, the estimated PM accumulation amount is stored in the storage unit 71, and based on the estimated PM accumulation amount In the engine 1 including the controller 7 that determines whether or not the DPF 62 is forcibly regenerated, the controller 7 determines whether or not the warm-up operation is completed after starting the engine, and forcibly regenerates the DPF 62. The post-reproduction elapsed time Tr is measured as an elapsed time from the start of the recording, and it is determined whether or not the measured post-reproduction elapsed time Tr exceeds the reference post-reproduction elapsed time Trc When the warm-up operation is completed and the measured post-regeneration elapsed time Tr is determined to have exceeded the post-regeneration elapsed time Trc, the amount of increase in the amount of particulate matter accumulated after the completion of the warm-up operation The post-warm-up PM accumulation amount increase ΔS2 is calculated, and the calculated post-warm-up PM accumulation amount increase ΔS2 is added to the PM accumulation amount Sb before engine start stored in the storage unit 71, and is obtained by integration. It is determined whether or not the PM deposition amount Sb + ΔS2 exceeds the reference deposition amount Sc, and the DPF 62 is forcibly regenerated when the accumulated PM deposition amount Sb + ΔS2 exceeds the reference deposition amount Sc.

  With such a configuration, by integrating the PM accumulation amount increase ΔS2 after warm-up to the PM accumulation amount Sb before starting the engine, an error from the actual PM accumulation amount is reduced. After the warm-up operation is completed, the reduced differential pressure is expected to recover. Therefore, the post-warm-up PM deposition amount increase ΔS2 calculated based on the differential pressure after the warm-up operation is completed is the actual particulate matter deposition amount. Matches the increment accurately. Also, only when time has passed since the previous forced regeneration, the previous forced regeneration is performed recently by determining whether or not forced regeneration is necessary based on the accumulated PM amount Sb + ΔS2. Until there is no excessive forced regeneration. That is, when the previous forced regeneration is performed recently, whether or not forced regeneration is necessary is determined based on the PM deposition amount Sa3 estimated from the reduced differential pressure instead of the accumulated PM deposition amount Sb + ΔS1. Therefore, the frequency with which forced regeneration is performed is suppressed. Therefore, it is possible to accurately estimate the amount of PM accumulated in the DPF 62 and perform the forced regeneration of the DPF 62 at an appropriate time.

1 Engine 7 Controller 62 DPF (Particulate Filter)
63 Differential pressure sensor 71 Storage unit Sa3 PM accumulation amount (particulate matter accumulation amount after completion of warm-up operation)
Sb Particulate matter deposition amount before engine start Sb + ΔS1 Particulate matter deposition amount obtained by integration Sb + ΔS2 Particulate matter deposition amount obtained by integration Sc Standard deposition amount Tr Elapsed time after regeneration (forcibly regenerating particulate filter Elapsed time since
Trc Elapsed time after reference regeneration Ts Elapsed time after startup Tsc Elapsed time after reference startup ΔS1 Increase in PM deposition amount after startup (Increase in particulate matter deposition amount after engine startup)
ΔS2 Increase in PM accumulation after warm-up (Increase in particulate matter accumulation after completion of warm-up operation)

Claims (3)

A particulate filter for collecting particulate matter contained in the exhaust gas;
A differential pressure sensor for detecting a differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter;
The differential pressure sensor is connected, and the particulate matter accumulation amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor, and the estimated particulate matter accumulation amount is stored in a storage unit, In an engine comprising: a controller that determines whether to regenerate the particulate filter based on the estimated particulate matter accumulation amount;
The controller is
Calculate the increase in the amount of particulate matter accumulated since the engine started,
The calculated increase in the amount of particulate matter accumulated after engine startup is added to the amount of particulate matter accumulated before engine startup stored in the storage unit,
Judging whether the accumulated amount of particulate matter obtained by the integration exceeds a predetermined reference accumulation amount,
An engine which forcibly regenerates the particulate filter when the accumulated amount of particulate matter obtained by integration exceeds the reference accumulation amount. A particulate filter for collecting particulate matter contained in the exhaust gas;
A differential pressure sensor for detecting a differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter;
The differential pressure sensor is connected, and the particulate matter deposition amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor, and the estimated particulate matter deposition amount is stored in a storage unit, In an engine comprising: a controller that determines whether to regenerate the particulate filter based on the estimated particulate matter accumulation amount;
The controller is
Determine if the warm-up operation is complete after the engine starts,
When it is determined that the warm-up operation has been completed, the amount of increase in the amount of particulate matter accumulated after the completion of the warm-up operation is calculated.
The calculated increase in the amount of particulate matter accumulated after completion of the warm-up operation is added to the amount of particulate matter accumulated before starting the engine stored in the storage unit,
Judging whether the accumulated amount of particulate matter obtained by the integration exceeds a predetermined reference accumulation amount,
An engine which forcibly regenerates the particulate filter when the accumulated amount of particulate matter obtained by integration exceeds the reference accumulation amount. A particulate filter for collecting particulate matter contained in the exhaust gas;
A differential pressure sensor for detecting a differential pressure between the exhaust gas upstream side and the exhaust gas downstream side of the particulate filter;
The differential pressure sensor is connected, and the particulate matter deposition amount of the particulate filter is estimated based on the differential pressure detected by the differential pressure sensor, and the estimated particulate matter deposition amount is stored in a storage unit, In an engine comprising: a controller that determines whether to regenerate the particulate filter based on the estimated particulate matter accumulation amount;
The controller is
Determine if the warm-up operation is complete after the engine starts,
Measure the elapsed time after forcibly regenerating the particulate filter,
Determine whether the measured elapsed time has passed a predetermined reference time,
When it is determined that the warm-up operation is completed and the measured elapsed time has passed the reference time, an increase in the amount of particulate matter accumulated after the completion of the warm-up operation is calculated,
The calculated increase in the amount of particulate matter accumulated after completion of the warm-up operation is added to the amount of particulate matter accumulated before starting the engine stored in the storage unit,
Judging whether the accumulated amount of particulate matter obtained by the integration exceeds a predetermined reference accumulation amount,
An engine which forcibly regenerates the particulate filter when the accumulated amount of particulate matter obtained by integration exceeds the reference accumulation amount.

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