JP6159671B2 - Engine exhaust treatment equipment - Google Patents

Description

  The present invention relates to an engine exhaust treatment apparatus, and more particularly to an engine exhaust treatment apparatus that can improve the accuracy of an estimated PM deposition value.

  Conventionally, as an exhaust treatment device for an engine, a DPF, a differential pressure sensor, and a PM accumulation value calculation device are provided. The DPF is disposed in an exhaust path, and the differential pressure sensor detects a differential pressure between an inlet and an outlet of the DPF. Some accumulation value calculation devices are configured to calculate the PM accumulation estimated value of the DPF based on the differential pressure detected by the differential pressure sensor (see, for example, Patent Document 1).

  According to this type of apparatus, it is expected that an accurate PM deposition estimated value can be obtained because the PM deposition estimated value is calculated using a differential pressure that is an index of clogging of the DPF.

  In this type of apparatus, the instantaneous PM deposition estimated value M based on the differential pressure is handled as the PM deposition estimated value.

JP 2009-281972 A (see FIG. 1)

<< Problem >> The accuracy of the PM deposition estimated value may be lowered.
In this type of device, the accuracy of the PM deposition estimate may be low.
The reason is that the instantaneous PM deposition estimated value M based on the differential pressure is handled as the PM deposition estimated value. Therefore, if the differential pressure fluctuates greatly due to disturbance such as exhaust pulsation, the accuracy of the PM deposition estimated value is greatly reduced. Presumed to be.

  An object of the present invention is to provide an exhaust treatment device for an engine that can improve the accuracy of an estimated PM deposition value.

  As a result of research, the inventors of the present invention set a stepwise PM deposition estimated value, and estimates the stepped PM deposition estimated value Ln based on the instantaneous PM deposition estimated value M, thereby causing disturbances such as exhaust pulsation. The present inventors have found that even if the differential pressure fluctuates greatly, it is difficult to be influenced by this, and the accuracy of the PM deposition estimated value can be improved, and the present invention has been achieved.

(Invention-specific matters common to the inventions of claims 1 and 3)
As illustrated in FIG. 1, a DPF (1), a differential pressure sensor (2), and a PM accumulation estimated value calculation device (3) are provided, and the DPF (1) is disposed in the exhaust path (4), and the differential pressure sensor ( 2) detects the differential pressure between the inlet (1a) and the outlet (1b) of the DPF (1), and the PM accumulation estimated value calculation device (3) is based on the differential pressure detected by the differential pressure sensor (2). In an exhaust treatment device for an engine configured to calculate a PM deposition estimated value of DPF (1),
As illustrated in FIG. 1 and FIG. 2, a storage device (5), a timing device (6), a reproduction processing device (7), and a reproduction control device (8) are provided.
The storage device (5) stores a plurality of stepwise PM deposition estimated values (Ln) that increase stepwise from an initial PM deposition estimated value (L0) to a regeneration required PM deposition estimated value (L5),
As illustrated in FIG. 2, the PM deposition estimated value calculation device (3) calculates an instantaneous PM deposition estimated value (M) based on the differential pressure ,
As illustrated in FIG. 3, when the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln), the accumulated time (T) exceeded by the timing device (6) is When measured (S5) and the accumulated time (T) reaches the update determination time (JTn), the stepwise PM deposition estimated value (Ln) is directly above the value (Ln + 1) by the PM deposition estimated value calculation device (3). (S7) and the updated value (Ln + 1) reaches the regeneration required PM accumulation estimated value (L5), the regeneration processing device (7) controls the DPF (1) under the control of the regeneration control device (5). The reproduction process is performed (S9) .
(Invention-specific matters specific to the invention of claim 1)
As illustrated in FIG. 3, if the instantaneous PM deposition estimated value (M) is equal to or lower than the current stepwise PM deposition estimated value (Ln) during the measurement of the accumulated time (T), the timing device (6 ), After the accumulated time (T) is once reset to 0 (S10), the measurement of the accumulated time (T) is resumed.
(Invention-specific matters specific to the invention of claim 3)
As illustrated in FIG. 3, when the instantaneous PM deposition estimate (M) exceeds the current stepwise PM deposition estimate (Ln) directly above (Ln + 1), PM An exhaust processing apparatus for an engine, characterized in that the current update determination time (JTn) is shortened (S4) by the estimated accumulation value calculation device (3).

(Invention of Claim 1)
The invention according to claim 1 has the following effects 1-1 and 1-2 .
<< Effect 1-1 >> The accuracy of the PM deposition estimated value can be increased.
As illustrated in FIG. 3, when the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln), the accumulated time (T) exceeded by the timing device (6) is When measured (S5) and the accumulated time (T) reaches the update determination time (JTn), the stepwise PM deposition estimated value (Ln) is directly above the value (Ln + 1) by the PM deposition estimated value calculation device (3). (S7) and the updated value (Ln + 1) reaches the regeneration required PM accumulation estimated value (L5), the regeneration processing device (7) controls the DPF (1) under the control of the regeneration control device (5). Since the regeneration process is performed (S9), even if the differential pressure fluctuates greatly due to a disturbance such as exhaust pulsation, it is not easily affected, and the accuracy of the PM deposition estimated value can be improved.

<< Effect 1-2 >> The accuracy of the PM deposition estimated value can be increased.
As illustrated in FIG. 3, if the instantaneous PM deposition estimated value (M) is equal to or lower than the current stepwise PM deposition estimated value (Ln) during the measurement of the accumulated time (T), the timing device (6 ) Once the accumulated time (T) is reset to 0 (S10), the measurement of the accumulated time (T) is resumed. Therefore, even if the differential pressure fluctuates greatly due to disturbance such as exhaust pulsation, the effect It is difficult to receive, and the accuracy of the PM deposition estimated value can be increased.

(Invention of Claim 2 )
The invention according to claim 2 has the following effect 2 in addition to effects 1-1 and 1-2 of the invention according to claim 1 .
<< Effect 2 >> The sensitivity of the deposition estimation can be increased.
As illustrated in FIG. 3, when the instantaneous PM deposition estimate (M) exceeds the current stepwise PM deposition estimate (Ln) directly above (Ln + 1), PM Since the current update determination time (JTn) is shortened (S4) by the estimated deposition value calculation device (3), if the PM deposition rate is fast, the sensitivity of PM deposition estimation can be increased accordingly. .
(Invention of Claim 3)
The invention according to claim 3 has the effect 2 of the invention according to claim 2 in addition to the effect 1-1 of the invention according to claim 1.

It is a mimetic diagram of a diesel engine provided with an exhaust treatment device concerning an embodiment of the present invention. It is a time chart which shows the relationship between the instantaneous PM deposition estimated value by the exhaust gas processing apparatus of FIG. It is a flowchart of the process by the exhaust processing apparatus of FIG.

  1 to 3 are diagrams for explaining an exhaust treatment device for an engine according to an embodiment of the present invention. In this embodiment, an exhaust treatment device for a diesel engine will be explained.

The outline of the exhaust treatment device of this engine is as follows.
As shown in FIG. 1, the exhaust treatment device of the engine (E) includes a DPF (1), a differential pressure sensor (2), and a PM accumulation estimated value calculation device (3), and the DPF (1) is connected to an exhaust path ( 4), the differential pressure sensor (2) detects the differential pressure between the inlet (1a) and the outlet (1b) of the DPF (1), and the PM deposition estimated value calculation device (3) is the differential pressure sensor (2 ) Is used to calculate the estimated PM deposition value of the DPF (1).

  DPF is an abbreviation for diesel particulate filter, and traps PM (particulate matter) in the exhaust (9). The PM accumulation estimated value calculation device (3) is a calculation device of the engine ECU (10). The engine ECU is an abbreviation for engine electronic control unit and is a microcomputer. The exhaust path (4) is led out from the exhaust manifold (11). The DPF (1) is accommodated in the DPF case (12) in the exhaust path (4). In the DPF case (12), a DOC (13) is accommodated upstream of the DPF (1). DOC is an abbreviation for diesel oxidation catalyst.

As shown in FIG. 1 and FIG. 2, this exhaust gas treatment device includes a storage device (5), a timekeeping device (6), a regeneration processing device (7), and a regeneration control device (8). A plurality of stepwise PM deposition estimated values (Ln) that increase stepwise from the initial PM deposition estimated value (L0) to the regeneration required PM deposition estimated value (L5) are stored.
As shown in FIG. 2, the instantaneous PM deposition estimated value (M) based on the differential pressure is calculated by the PM deposition estimated value calculation device (3) .
As shown in FIG. 3, when the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln), the accumulated time (T) exceeded by the timing device (6) is measured. (S5) When the accumulated time (T) reaches the update determination time (JTn), the stepwise PM deposition estimated value (Ln) is set to the directly above value (Ln + 1) by the PM deposition estimated value calculation device (3). When updated (S7) and the updated value (Ln + 1) reaches the regeneration required PM accumulation estimated value (L5), the regeneration processing device (7) regenerates the DPF (1) under the control of the regeneration control device (5). Processing is performed (S9).

As shown in FIG. 1, the storage device (5) is a storage device of the engine ECU (10). The timing device (6) is a timing device of the engine ECU (10). The regeneration processing device (7) is composed of a DOC (13) and a common rail fuel injection device (14), and unburned fuel is mixed into the exhaust (9) by post injection of the common rail fuel injection device (14). The unburned fuel is catalytically combusted by DOC (13) with oxygen in the exhaust (9), the exhaust (9) is heated, PM deposited on the DPF (1) is incinerated and removed, and the DPF (1 ). The regeneration control device (8) is a command device for the engine ECU (10).
Each fuel injector (14a) of the common rail fuel injection device (14) is inserted into each cylinder (C1) to (C4) of the engine (E), and fuel is supplied via the common rail (14b) and the fuel supply pump (14c). It is connected to the tank (14d).

The storage device (5) has six stepwise PM deposition estimated values (Ln) that increase stepwise from the initial PM deposition estimated value (L0) to the regeneration required PM deposition estimated value (L5) shown in FIG. It is remembered. In this embodiment, the six stepwise PM deposition estimated values (Ln) and the update determination time (JTn) are the experimentally obtained instantaneous PM deposition estimated value (M) and the stepped PM deposition estimated value ( Ln) is set based on the correlation with Ln). The cumulative time (T) may be the cumulative time during which the instantaneous PM deposition estimated value (M) continuously exceeds the current stepwise PM deposition estimated value (Ln), or may be intermittently exceeded. It may be accumulated time.
The initial PM deposition estimated value (L0) is the estimated PM deposition value of DPF (1) when the engine is started after shipment from the factory or after replacement of DPF (1) and after regeneration processing of DPF (1). It is.

  As shown in FIG. 3, during the measurement of the accumulated time (T), if the instantaneous PM deposition estimated value (M) becomes equal to or less than the current stepwise PM deposition estimated value (Ln), the timing device (6) After the accumulated time (T) is once reset to 0 (S10), the measurement of the accumulated time (T) is resumed. In this case, the cumulative time (T) is the cumulative time during which the instantaneous PM deposition estimated value (M) continuously exceeds the current stepwise PM deposition estimated value (Ln).

As shown in FIG. 3, when the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln) (Ln + 1), the PM deposition is higher than when it does not exceed. The estimated value calculation device (3) shortens the current update determination time (JTn) (S4). The update determination time (JTn) reduction (S4) is applied when the instantaneous PM deposition estimated value (M) exceeds a value (Ln + 1) immediately above the current stepwise PM deposition estimated value (Ln) for a predetermined time.
The time in this case may be a continuous accumulation of time or an intermittent accumulation of time.

The time chart of FIG. 2 will be described.
The current stepwise PM deposition estimate (Ln) is the initial PM deposition estimate (L0), and the cumulative time (T) when the instantaneous PM deposition estimate (M) exceeds the initial PM deposition estimate (L0) is updated. When the determination time (JT0) is reached, the stepwise PM deposition estimated value (Ln) is updated from the initial PM deposition estimated value (L0) to the value directly above (L1).
Since the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L0) directly above the value (L1) for a predetermined time, the PM deposition estimated value calculation device (3) is more than the case where it is not exceeded. Thus, the update determination time (JT0) is shortened.

Next, when the accumulated time (T) when the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L1) reaches the update determination time (JT1), the stepwise PM deposition estimated value ( Ln) is updated from the current stepwise PM deposition estimate (L1) to its immediate upper value (L2).
Since the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L1) directly above the value (L2) for a predetermined time, the PM deposition estimated value calculation device (3) is more than that when it is not exceeded. Thus, the update determination time (JT1) is shortened.

Next, when the accumulated time (T) when the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L2) reaches the update determination time (JT2), the stepwise PM deposition estimated value ( Ln) is updated from the current stepwise PM deposition estimate (L2) to its immediate upper value (L3).
Since the instantaneous PM deposition estimated value (M) before the update does not exceed the value (L3) immediately above the stepwise PM deposition estimated value (L2), the update determination time (JT2) is not shortened.

Next, when the accumulated time (T) when the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L3) reaches the update determination time (JT3), the stepwise PM deposition estimated value ( Ln) is updated from the current stepwise PM deposition estimate (L3) to its immediate upper value (L4).
Before updating, the instantaneous PM deposition estimated value (M) exceeds the stepwise PM deposition estimated value (L3) directly above the value (L4) for a predetermined time. In (3), the update determination time (JT3) is shortened.

  Next, when the accumulated time (T) when the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (L4) reaches the update determination time (JT4), the stepwise PM deposition estimated The value (Ln) is updated from the current stepwise PM deposition estimated value (L4) to the regeneration required PM deposition estimated value (L5) that is immediately above it.

The flowchart of the processing by the exhaust processing device is as follows.
As shown in FIG. 3, in step (S1), an instantaneous PM deposition estimated value (M) based on the differential pressure is calculated, and the process proceeds to step (S2).
In step (S2), it is determined whether or not the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM estimated value Ln. If the determination is affirmative, the process proceeds to step (S3).
In step (S3), it is determined whether or not the instantaneous PM deposition estimated value (M) exceeds a value (Ln + 1) immediately above the current stepwise PM estimated value Ln for a predetermined time. If the determination is affirmative, the process proceeds to step (S4).
In step (S4), the current update determination time (JTn) is shortened, and the process proceeds to step (S5).
In step (S5), the accumulated accumulated time (T) is measured, and the process proceeds to step (S6).

In step (S6), it is determined whether or not the accumulated time (T) has reached the update determination time (JTn). If the determination is affirmative, the process proceeds to step (S7).
In step (S7), the current stepwise PM deposition estimated value (Ln) is updated to the directly above value (Ln + 1), and the process proceeds to step (S8).
In step (S8), it is determined whether or not the updated value (Ln + 1) has reached the regeneration required PM accumulation estimated value (L5). If the determination is positive, the process proceeds to step (S9).
In step (S9), a reproduction process is performed.

If the determination in step (S2) is negative, the process proceeds to step (S10).
In step (S10), the accumulated time (T) is once reset to 0, and the process returns to step (S1).
If the determination in step (S3) is negative, the process proceeds to step (S5).
If the determinations in steps (S6) and (S8) are negative, both return to step (S1).

(1) DPF
(1a) Entrance
(1b) Exit
(2) Differential pressure sensor
(3) PM deposition estimated value calculation device
(4) Exhaust route
(5) Storage device
(6) Timing device
(7) Reproduction processing device
(8) Reproduction control device
(L0) Estimated initial PM deposition
(L5) Estimated PM accumulation required for regeneration
(Ln) Stepwise PM deposition estimate
(Ln + 1) Directly above price
(M) Instantaneous PM deposition estimate
(T) Cumulative time
(JTn) Update judgment time
(S3) Accumulated time is measured
(S5) Update to the directly above price
(S7) Playback processing is implemented
(S8) Reset
(S10) Update judgment time is shortened

Claims (3)

A DPF (1), a differential pressure sensor (2), and a PM accumulation estimated value calculation device (3) are provided. The DPF (1) is disposed in the exhaust path (4), and the differential pressure sensor (2) is connected to the DPF (1). The differential pressure between the inlet (1a) and the outlet (1b) is detected, and the PM deposition estimated value calculation device (3) is based on the differential pressure detected by the differential pressure sensor (2), and the PM deposition of the DPF (1). In an exhaust treatment device for an engine configured to calculate an estimated value,
A storage device (5), a timing device (6), a regeneration processing device (7), and a regeneration control device (8);
The storage device (5) stores a plurality of stepwise PM deposition estimated values (Ln) that increase stepwise from an initial PM deposition estimated value (L0) to a regeneration required PM deposition estimated value (L5),
The PM deposition estimated value calculation device (3) calculates an instantaneous PM deposition estimated value (M) based on the differential pressure ,
When the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln), the accumulated time (T) exceeded by the timing device (6) is measured (S5), and the accumulated time When (T) reaches the update determination time (JTn), the PM deposition estimated value calculation device (3) updates the stepwise PM deposition estimated value (Ln) to the immediately above value (Ln + 1) (S7). If that has reached the value (Ln + 1) is essential reproducing PM accumulation estimated value (L5), the reproduction processing of the DPF (1) is performed (S9) by the reproducing apparatus under the control of the reproduction control apparatus (5) (7) And
During the measurement of the accumulated time (T), when the instantaneous PM deposition estimated value (M) becomes less than the current stepwise PM deposition estimated value (Ln), the accumulated time (T) is calculated by the timing device (6). An exhaust processing apparatus for an engine, characterized in that the measurement of the accumulated time (T) is resumed after being reset to 0 (S10) once. The engine exhaust treatment apparatus according to claim 1 ,
When the instantaneous PM deposition estimated value (M) exceeds the value (Ln + 1) immediately above the current stepwise PM deposition estimated value (Ln), the PM deposition estimated value calculation device (3) The engine exhaust processing apparatus is characterized in that the current update determination time (JTn) is shortened (S4). A DPF (1), a differential pressure sensor (2), and a PM accumulation estimated value calculation device (3) are provided. The DPF (1) is disposed in the exhaust path (4), and the differential pressure sensor (2) is connected to the DPF (1). The differential pressure between the inlet (1a) and the outlet (1b) is detected, and the PM deposition estimated value calculation device (3) is based on the differential pressure detected by the differential pressure sensor (2), and the PM deposition of the DPF (1). In an exhaust treatment device for an engine configured to calculate an estimated value,
A storage device (5), a timing device (6), a regeneration processing device (7), and a regeneration control device (8);
The storage device (5) stores a plurality of stepwise PM deposition estimated values (Ln) that increase stepwise from an initial PM deposition estimated value (L0) to a regeneration required PM deposition estimated value (L5),
The PM deposition estimated value calculation device (3) calculates an instantaneous PM deposition estimated value (M) based on the differential pressure ,
When the instantaneous PM deposition estimated value (M) exceeds the current stepwise PM deposition estimated value (Ln), the accumulated time (T) exceeded by the timing device (6) is measured (S5), and the accumulated time When (T) reaches the update determination time (JTn), the PM deposition estimated value calculation device (3) updates the stepwise PM deposition estimated value (Ln) to the immediately above value (Ln + 1) (S7). If that has reached the value (Ln + 1) is essential reproducing PM accumulation estimated value (L5), the reproduction processing of the DPF (1) is performed (S9) by the reproducing apparatus under the control of the reproduction control apparatus (5) (7) And
When the instantaneous PM deposition estimated value (M) exceeds the value (Ln + 1) immediately above the current stepwise PM deposition estimated value (Ln), the PM deposition estimated value calculation device (3) The engine exhaust processing apparatus is characterized in that the current update determination time (JTn) is shortened (S4).

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