JP6326392B2 - Engine exhaust treatment equipment - Google Patents

Description

  The present invention relates to an engine exhaust treatment device, and more particularly to an engine exhaust treatment device capable of preventing failure of regeneration processing of an exhaust purification unit.

2. Description of the Related Art Conventionally, there are the following exhaust processing apparatuses for engines (see, for example, Patent Document 1).
When the exhaust purification unit is provided with an exhaust purification unit, a combustible gas generator, and a control device, and the regeneration processing of the exhaust purification unit is performed by the control of the control device, fuel is supplied to the combustible gas generation catalyst of the combustible gas generator. An exhaust treatment apparatus for an engine configured to raise the temperature of exhaust gas by combustion of the generated combustible gas.

  According to this type of exhaust treatment device, even when the exhaust gas temperature is low, the exhaust gas is heated by combustion of the combustible gas, and the deposits of the exhaust gas purification unit are incinerated and removed by the heated exhaust gas, so that the exhaust gas purification unit There is an advantage that can be reproduced.

  In this type of exhaust treatment device, the warm-up process of the combustible gas generating catalyst is performed by the control device before the regeneration process is performed. This warm-up process is automatically performed as the set time elapses. May be terminated.

JP 2011-52599 A (see FIG. 2)

<< Problem >> There is a risk that the regeneration process of the exhaust purification unit may fail.
If the warm-up process is automatically terminated after the set time elapses, the combustible gas generation catalyst will not be warmed up in cold weather, and the generation of combustible gas will stagnate and the exhaust purification unit will be regenerated. Processing may fail.

  An object of the present invention is to provide an exhaust treatment device for an engine that can prevent a failure of regeneration processing of an exhaust purification unit.

  As a result of research, the inventors of the present invention add a warm-up determination process to the warm-up process, and determine whether the temperature of the combustible gas generation catalyst has reached a predetermined warm-up determination temperature at the time of warm-up determination. In the case of a warm-up failure determination in which the determination is negative, it is found that restarting the warm-up process can prevent a shortage of warm-up and prevent a failure in the regeneration process of the exhaust purification unit. This has led to the present invention.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1, an exhaust purification unit (1), a combustible gas generator (2), and a control device (3) are provided.
As illustrated in FIG. 3, when the regeneration process of the exhaust purification unit (1) is performed (S <b> 6) (S <b> 8) under the control of the control device (3), the combustible gas is illustrated as illustrated in FIG. 1. The fuel (5) is supplied to the combustible gas generating catalyst (4) of the generator (2), and the temperature of the exhaust (8) is raised by combustion of the generated combustible gas (6). Engine exhaust treatment equipment,
As illustrated in FIG. 3, before the regeneration process is performed (S <b> 6) (S <b> 8), the warm-up process of the combustible gas generation catalyst (4) is performed under the control of the control device (3),
This warm-up process includes a heating process (S2) (S2 '), a subsequent catalytic combustion temperature raising process (S3) (S3'), and a warm-up determination process (S4), and is exemplified in FIG. 2 (A) and FIG. As described above, in the catalyst combustion temperature raising process (S3) (S3 ′), the fuel (5) is supplied to the combustible gas generating catalyst (4), and the combustible gas generating catalyst is obtained by catalytic combustion of the fuel (5). In the case where the temperature (T3) in (4) is raised and the warm-up failure determination in the warm-up determination process (S4) is determined, the catalyst combustion temperature increase process (S3) (S3 ') is terminated and the heat treatment is performed. The warm-up process starting from (S2 ′) is resumed,
As illustrated in FIG. 2C, in the initial catalyst warming-up process (S3) of the warm-up process, the initial fuel increase supply speed (Q3-1) of the initial fuel increase supply process (S3-1) The engine exhaust treatment apparatus is set to a value higher than the post-initial fuel supply speed (Q3-3) of the initial post-fuel supply process (S3-3).

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> It is possible to prevent failure of the regeneration process of the exhaust gas purification unit.
As illustrated in FIG. 2A, in the case of the warm-up failure determination in the warm-up determination process (S4), the warm-up process starting from the heating process (S2 ′) is resumed. Therefore, even when it is cold, it is possible to prevent the combustible gas generating catalyst (4) from being insufficiently warmed up, promote the generation of the combustible gas (6), and regenerate the exhaust purification section (1). Failure can be prevented.

<Effect> It is possible to suppress fuel consumption due to useless continuation of the catalytic combustion temperature raising process.
As shown in FIG. 2A, in the case of the warm-up failure determination, the catalyst combustion temperature raising process (S3) is terminated, and the warm-up process starting from the heating process (S2 ') is resumed. It is possible to suppress the consumption of the fuel (5) due to the wasteful continuation of the combustion temperature raising process (S3) (S3 ').

<Effect> Failure of the first warm-up process can be suppressed.
As illustrated in FIG. 2C, in the initial catalyst warming-up process (S3) of the warm-up process, the initial fuel increase supply speed (Q3-1) of the initial fuel increase supply process (S3-1) Is set to a value higher than the initial fuel supply speed (Q3-3) in the initial fuel supply process (S3-3). Therefore, in the first warm-up operation, empty fuel that is not filled with fuel (5) is set. The fuel (5) is supplied to the piping and the combustible gas generating catalyst (4) at a high speed, and these are filled with the fuel (5) at an early stage, so that failure of the initial warm-up process can be suppressed.

(Invention of Claim 2)
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> Incomplete combustion in the restarted warm-up process can be prevented.
As illustrated in FIG. 2C, in the restarted catalyst combustion temperature raising process (S3 ′) of the warm-up process, a fuel resupply process (S3′-3) that is not accompanied by the initial fuel increase supply process is performed. Therefore, excess fuel (5) is not supplied to the combustible gas generating catalyst (4) to which fuel (5) has already been supplied, and incomplete combustion in the restarted warm-up process can be prevented. .

(Invention of Claim 3)
The invention according to claim 3 has the following effect in addition to the effect of the invention according to claim 2.
<Effect> The success rate of the restarted warm-up process can be increased.
As illustrated in FIG. 2C, the fuel resupply speed (Q3′-1) of the fuel resupply process (S3′-1) is the same as that of the initial warm-up process after the initial fuel supply process (S3-3). Since it is set to a value higher than the initial fuel supply speed (Q3-3), the restarted warm-up process supplies fuel to the combustible gas generating catalyst (4) as compared to the initial warm-up process. The speed increases and the success rate of the restarted warm-up process can be increased.

(Invention of Claim 4)
The invention according to claim 4 has the following effects in addition to the effects of the invention according to any one of claims 1 to 3.
<Effect> It is possible to suppress the failure of the initial warm-up process during cold weather.
As illustrated in FIG. 1, a temperature sensor (28) is provided, and the temperature sensor (28) is linked to the control device (3), and the engine coolant (29), engine oil, and engine machine wall are linked by the temperature sensor (28). And the fuel (5) are detected, and the lower the detected temperature is, the lower the detected temperature is, the control device (3) starts the initial fuel supply rate (Q3) in the first warm-up process illustrated in FIG. Since the target value of -1) is set to a high value, the supply of the fuel (5) is delayed to the combustible gas generating catalyst (4) due to an increase in the viscosity of the fuel (5) during cold weather. And the failure of the initial warm-up process during cold weather can be suppressed.

(Invention according to claim 5)
The invention according to claim 5 has the following effects.
<Effect> It is possible to prevent failure of the regeneration process of the exhaust gas purification unit.
As illustrated in FIG. 2A, in the warm-up determination process (S4), whether or not the temperature (T3) of the combustible gas generation catalyst (4) has reached a predetermined warm-up determination temperature (T4-1). In the case of the warm-up failure determination in the warm-up determination processing (S4) in which the determination is negative from the start of the warm-up processing until the warm-up failure determination time (t4-2) after a predetermined time has elapsed, Since the warm-up process starting from the heat process (S2 ′) is resumed, the temperature (T3) of the combustible gas generation catalyst (4) is warmed to the predetermined warm-up determination temperature (T4-1). Even when it is cold, it is possible to prevent the combustible gas generating catalyst (4) from being insufficiently warmed up, promote the generation of the combustible gas (6), and The failure of the reproduction process 1) can be prevented.

(Invention of Claim 6)
The invention according to claim 6 has the following effect in addition to the effect of the invention according to claim 5.
<Effect> It is possible to suppress fuel consumption due to an unnecessarily prolonged catalyst combustion temperature raising process.
As illustrated in FIG. 2B, in the case of the warm-up failure prediction determination, the warm-up process starting from the heating process (S2 ′) after the catalytic combustion temperature raising process (S3) is finished is shown in FIG. Since it is configured to be resumed at a time earlier than the warm-up determination time (t4-2) exemplified in A), the catalyst combustion temperature raising process (S3) where failure is predicted is terminated early. Further, it is possible to suppress the consumption of the fuel (5) due to the wasteful lengthening of the catalyst combustion temperature raising process (S3).

(Invention of Claim 7)
The invention according to claim 7 has the following effects in addition to the effects of the invention according to any one of claims 1 to 6.
<Effect> The success rate of the restarted warm-up process can be increased.
As illustrated in FIG. 4B, the heating time (t2 ′) of the heating process (S2 ′) of the restarted warm-up process is also combustible gas before the heating process (S2) first performed before the restarting. Since it is configured to be set based on the temperature (T3) of the produced catalyst (4), the combustible gas producing catalyst (4) that has already been heated to some extent in the resumed heat treatment (S2 ′). However, it takes a heating time (t2 ′) set based on the temperature (T3) of the combustible gas generating catalyst (4) before the first heat treatment (S2), and is carefully reheated and restarted. The success rate of machine processing can be increased.

(Invention of Claim 8)
The invention according to claim 8 has the following effects in addition to the effects of the invention according to any one of claims 1 to 7.
<Effect> The DPF can be regenerated.
As illustrated in FIG. 1, the exhaust purification unit (1) includes a DPF (11), and in the regeneration process of the DPF (11), PM deposited on the DPF (11) is combusted and removed. Therefore, the DPF (11) can be regenerated.

(Invention according to claim 9)
The invention according to claim 9 has the following effects in addition to the effects of the invention according to any one of claims 1 to 8.
<Effect> DOC playback becomes possible.
As illustrated in FIG. 1, the exhaust purification unit (1) includes a DOC (12), and in the regeneration process of the DOC (12), the PM deposited on the DOC (12) is incinerated and removed. Therefore, DOC (12) can be reproduced.

(Invention of Claim 10)
The invention according to claim 10 has the following effects in addition to the effects of the inventions according to claims 1 to 9.
<Effect> DOC regeneration and warm-up of the DOC at light load are possible.
As illustrated in FIG. 1, an ignition device (13) for combustible gas (6) is provided, the exhaust purification unit (1) is provided with a DOC (12), and the ignition device (13) is an exhaust upstream of the DOC (12). Since the combustible gas (6) is ignited by the ignition device (13) and the temperature of the exhaust (8) is raised by flame combustion of the combustible gas (6), The regeneration of the DOC (12) and the warm-up of the DOC (12) at a light load when the temperature of the exhaust (8) is low are possible.

It is a mimetic diagram of an engine exhaust treatment device concerning an embodiment of the present invention. 2A is a time chart of the warm-up process, FIG. 2B is a time chart of the warm-up process accompanied by the warm-up failure prediction determination, and FIG. 2C is a time chart explaining the fuel supply speed. It is a main flowchart of control by the control apparatus of the apparatus of FIG. 4A is a sub-flowchart for explaining the details of the heating process (S2) of the first warm-up process, and FIG. 4B is a sub-flowchart for explaining the details of the heating process (S2 ′) of the restarted warm-up process. It is a flowchart. FIG. 5A is a sub-flowchart for explaining the details of the first catalyst warming-up process (S3), and FIG. 5B is the restarted catalyst combustion temperature-raising process (S3 ′). It is a sub-flowchart explaining the details. It is a subflowchart explaining the detail of warm-up determination processing (S4). 2 is a time chart of regeneration of DPF (11) and regeneration determination of DOC (12) by the exhaust treatment device of FIG.

  FIGS. 1-7 is a figure explaining the exhaust processing apparatus of the engine which concerns on embodiment of this invention, and this embodiment demonstrates the exhaust processing apparatus of a diesel engine.

The outline of the exhaust treatment device is as follows.
As shown in FIG. 1, the exhaust treatment device includes an exhaust purification unit (1), a combustible gas generator (2), and a control device (3).
As shown in FIG. 3, when the regeneration process of the exhaust purification unit (1) is carried out (S6) (S8) by the control of the control device (3), as shown in FIG. 1, a combustible gas generator The fuel (5) is supplied to the combustible gas generating catalyst (4) of (2), and the temperature of the exhaust (8) is raised by combustion of the generated combustible gas (6). .

As shown in FIG. 1, the exhaust gas purification unit (1) includes a DPF (11) and a DOC (12). The DPF (11) and the DOC (12) are accommodated in the exhaust purification case (14), and the DOC (12) is disposed on the upstream side of the DPF (11). DPF is an abbreviation for diesel particulate filter, and DOC is an abbreviation for diesel oxidation catalyst.
The DPF (11) is a wall flow type ceramic honeycomb having a plurality of cells arranged in parallel in the axial length direction and alternately sealing the start and end of adjacent cells. The oxidation catalyst component is formed on the inner surface of each cell. Is carried.
The DOC (12) is a through-flow type ceramic honeycomb having a plurality of cells arranged in parallel in the axial direction, with the start and end of all cells being opened, and an oxidation catalyst component is supported on the inner surface of the cell. ing.
An ignition device (13) for the combustible gas (6) is disposed on the exhaust upstream side of the DOC (12). The ignition device (13) is an electrothermal glow plug.
An SCR catalyst or a NOx storage catalyst can be used for the exhaust purification unit (1). SCR catalyst is an abbreviation for selective reduction catalyst, and NOx is an abbreviation for nitrogen oxides.

As shown in FIG. 1, the combustible gas generator (2) generates combustible gas (6) from the air-fuel mixture (18) by the catalytic reaction of the combustible gas generating catalyst (4).
A combustible gas generating catalyst (4) is accommodated in the combustible gas generator (2), and an air / fuel mixing chamber (15) is provided above the combustible gas generating catalyst (4). An air-fuel mixture inlet (16) recessed downward is provided at the upper center of the combustible gas generating catalyst (4). Liquid fuel (5) and primary air (17) are supplied to the air-fuel mixing chamber (15), and these are mixed to form an air-fuel mixture (18), which is combustible from the air-fuel mixture inlet (16). It is supplied to the gas generating catalyst (4). A gas generation start catalyst (19) is accommodated in the gas mixture inlet (16), and a heater (9) is inserted therein.
The combustible gas generating catalyst (4) is a woven iron chrome wire, and the rhodium catalyst component is supported on the iron chrome wire. The gas generation start catalyst (19) is an alumina fiber mat, on the surface of which a rhodium catalyst component is supported. The gas generation start catalyst (19) has higher fuel (5) retention than the combustible gas generation catalyst (4).
Light oil is used as the fuel (5).
The control device (3) is an engine ECU and is a microcomputer. ECU is an abbreviation for electronic control unit.

As shown in FIG. 1, in the regeneration process of the DPF (11), the temperature of the exhaust (8) is raised by catalytic combustion of the combustible gas (6) in the DOC (12), and the exhaust (8 The PM deposited on the DPF (11) is removed by incineration. During light load operation where the temperature of the exhaust (8) does not reach the activation temperature of the DOC (12), the combustible gas (6) is ignited by the ignition device (13) and exhausted by flame combustion of the combustible gas (6). After the temperature of (8) is raised and the temperature of the DOC (12) is raised to the activation temperature, the temperature of the exhaust (8) is raised by catalytic combustion of the combustible gas (6) in the DOC (12). .
In the regeneration process of the DOC (12), the combustible gas (6) is ignited by the ignition device (13), the exhaust (8) is heated by the flame combustion of the combustible gas (6), and the exhaust ( In 8), PM deposited on the DOC (12) is burned and removed.
The regeneration process of the exhaust purification unit (1) may be an incineration process of sulfur compounds accumulated in the exhaust purification unit (1).

As shown in FIG. 3, in this exhaust treatment apparatus, before the regeneration process is carried out (S6) (S8), the warm-up process of the combustible gas generating catalyst (4) is performed under the control of the control device (3). To be implemented.
This warm-up process includes a heat process (S2) (S2 '), a subsequent catalyst combustion temperature raising process (S3) (S3'), and a warm-up determination process (S4), as shown in FIGS. Thus, in the catalyst combustion temperature raising process (S3) (S3 '), the fuel (5) is supplied to the combustible gas generating catalyst (4), and the combustible gas generating catalyst ( In the case where the temperature (T3) of 4) is raised and the warm-up failure determination in the warm-up determination process (S4) is determined, the catalyst combustion temperature increase process (S3) (S3 ′) is ended and the heating process ( The warm-up process starting from S2 ′) is resumed.
For this reason, it is guaranteed that the temperature (T3) of the combustible gas generation catalyst (4) is warmed up to a predetermined warm-up determination temperature (T4-1), and even in cold weather, the combustible gas generation catalyst It is possible to prevent the warm-up shortage of (4), promote the generation of the combustible gas (6) during the regeneration process, and prevent the regeneration process failure of the exhaust gas purification unit (1). Further, it is possible to suppress consumption of the fuel (5) due to wasteful continuation of the catalyst combustion temperature raising process (S3) (S3 ').
In the heat treatment (S2) (S2 '), the combustible gas generating catalyst (4) is heated by the heat generated by the heater (9).

As shown in FIG. 2 (C), in the first catalyst warming-up process (S3) of the warm-up process, the initial fuel increase supply rate (Q3-1) is higher than the subsequent initial fuel supply rate (Q3-3). Is also set to a high value.
For this reason, in the first warm-up operation, the fuel (5) is supplied at high speed to the empty pipe or the combustible gas generating catalyst (4) that is not filled with the fuel (5), and these are quickly supplied to the fuel (5). The first warm-up process failure can be suppressed.

As shown in FIG. 2 (C), in the reactivated warming-up catalyst combustion temperature increasing process (S3 ′), a fuel resupply process (S3′-3) that is not accompanied by an initial fuel increase supply process is performed. .
For this reason, excess fuel (5) is not supplied to the combustible gas generating catalyst (4) to which fuel (5) has already been supplied, and incomplete combustion in the restarted warm-up process can be prevented. .

As shown in FIG. 2C, the fuel resupply speed (Q3'-3) of the fuel resupply process (S3'-3) is the fuel of the initial warm-up process after the initial fuel supply process (S3-3). It is set to a value higher than the post-initial supply speed (Q3-3).
For this reason, in the restarted warm-up process, the fuel supply speed to the combustible gas generating catalyst (4) is increased compared to the first warm-up process, and the success rate of the restarted warm-up process can be increased. .

As shown in FIG. 1, a temperature sensor (28) is provided, and the temperature sensor (28) is linked to the control device (3), and the temperature of the engine coolant (29) is detected and detected by the temperature sensor (28). The control device (3) is configured to set the target value of the fuel initial increase supply rate (Q3-1) in the first warm-up process illustrated in FIG. 2 (C) to a higher value as the temperature decreases. ing. The temperature detected by the temperature sensor (28) may be any of engine oil, engine machine wall, and fuel (5).
Therefore, the increase in the viscosity of the fuel (5) at the time of cold prevents the fuel (5) from being delayed from being supplied to the combustible gas generating catalyst (4), and the failure of the first warm-up process at the time of cold is suppressed. be able to.
The control of the fuel supply speed is feedforward control of the fuel feed pump (30) by the control device (3). When the target value of the initial fuel increase supply speed (Q3-1) is set to a high value, the fuel supply speed per unit time is controlled. The number of pumping times of the fuel feed pump (30) increases.

As shown in FIG. 2A, in the warm-up determination process (S4), whether or not the temperature (T3) of the combustible gas generation catalyst (4) has reached a predetermined warm-up determination temperature (T4-1). If the determination is negative from the start of the warm-up process to the time of warm-up failure determination after the elapse of a predetermined time (t4-2), a warm-up failure determination is made.
For this reason, it is guaranteed that the temperature (T3) of the combustible gas generation catalyst (4) is warmed up to a predetermined warm-up determination temperature (T4-1), and even in cold weather, the combustible gas generation catalyst Insufficient warm-up of (4) can be prevented, generation of combustible gas (6) can be promoted, and failure of regeneration processing of exhaust purification unit (1) can be prevented.

As shown in FIG. 2B, warm-up prediction determination is performed in the warm-up determination process (S4). In this warm-up prediction determination, the peak temperature (P) of the combustible gas generation catalyst (4) is determined. At the time of warm-up prediction determination after the elapse of a predetermined time (t4-3) from the occurrence of the occurrence of the temperature, the temperature of the combustible gas generation catalyst (4) is changed from the peak temperature (P) to the predetermined warm-up failure prediction determination temperature (T4- 4) In the case of the warm-up failure prediction determination in which it is determined whether or not it has been lowered or not, and the determination is affirmative, the catalyst combustion temperature raising process (S3) is terminated and the warm-up starting from the heating process (S2 ') is performed. The process is configured to resume at a time earlier than the warm-up failure determination time (t4-2) shown in FIG.
For this reason, the catalyst combustion temperature rising process (S3) in which failure is predicted can be terminated early, and the consumption of the fuel (5) due to the wasteful lengthening of the catalyst combustion temperature increasing process (S3) can be suppressed.

As shown in FIG. 1, this exhaust treatment apparatus includes a catalyst temperature sensor (10) of the combustible gas generating catalyst (4), and is detected by the catalyst temperature sensor (10) as shown in FIG. 4 (A). Based on the temperature (T3) of the combustible gas generating catalyst (4) before the heat treatment, the control device (3) sets the heating time (t2) of the first warm-up heat treatment (S2) ( As shown in FIG. 4 (B), the heating time (t2 ′) of the heating process (S2 ′) of the restarted warm-up process is also the first heating process (S2) performed before restarting. It is configured to be set based on the temperature (T3) of the previous combustible gas generating catalyst (4).
For this reason, in the restarted heat treatment (S2 ′), the combustible gas generating catalyst (4) whose temperature has already been raised to some extent is changed to the temperature (4) of the combustible gas generating catalyst (4) before the first heat treatment (S2). It is possible to increase the success rate of the warm-up process that is reheated and restarted carefully over the heating time (t2 ′) set based on T3).
In this embodiment, as shown in FIGS. 2A and 2B, the heating time (t2 ′) of the resumed heating process (S2 ′) is the same as that of the heating process (S2) first performed before the restarting. It is configured to be set to the same length as the heating time (t2). The heating time (t2 ′) of the resumed heating process (S2 ′) is set to a length of 80 to 120% of the length of the heating time (t2) of the heating process (S2) performed first before the restarting. It is desirable to set the length to 90 to 110%.

A time chart of warm-up processing by the exhaust processing device will be described.
As shown in FIG. 2A, in the first warm-up process, the heating time (t2) is set (S2-1) based on the detected temperature (T3) of the gas generating catalyst (4), and heating is started ( When the heating time (t2) elapses, the heating is completed (S2-4), the catalyst combustion temperature raising process (S3) is performed, and the gas generation catalyst temperature (T3) is set to the warm-up determination temperature (T4). -1), the warm-up success determination is made in the warm-up determination process (S4), the warm-up process is terminated, the DPF (11) regeneration process is performed (S6), or the DOC (12 ) Is performed (S8). In the case of the warm-up failure determination in which the determination has been denied until the warm-up failure determination time (t4-2), the warm-up process starting from the heating process (S2 ′) is resumed.
Even in the restarted warm-up process, the heating time (t2 ′) is set (S2′-1), the heating is started (S2′-2), and the heating ends (S2) when the heating time (t2 ′) elapses. -4) and the catalyst combustion temperature raising process (S3 ') is started, the heating time (t2') is the same length as the heating time (t2) of the first heating process (S2) before restarting. is there.

In the warm-up process with the warm-up failure prediction determination shown in FIG. 2 (B), the warm-up prediction determination is performed in the warm-up determination process (S4). In this warm-up prediction determination, the combustible gas generation catalyst is determined. At the time of warm-up prediction determination (t4-3) after elapse of a predetermined time from the occurrence of the peak temperature (P) in (4), the temperature of the combustible gas generating catalyst (4) is predetermined from the peak temperature (P). In the case of the warming-up failure prediction determination in which it is determined whether or not the temperature has continuously decreased over the warm-up failure prediction determination temperature (T4-4), and the determination is affirmative, the warming-up process starting from the heating process (S2 ′) However, it is configured to resume at a time earlier than the warm-up failure determination time (t4-2) shown in FIG.
Note that the conditions for establishing the warm-up failure prediction determination are limited to the case where the temperature of the combustible gas generation catalyst (4) continuously decreases, but the case where the temperature decreases discontinuously with a temporary increase. In addition, the determination satisfaction condition can be relaxed so that the determination is satisfied.

  As shown in FIG. 2 (C), the initial increased supply rate (Q3-1) of the fuel (5) in the catalyst combustion temperature raising process (S3) of the first warm-up process is the initial post-supply rate (Q3-3). Is set to a higher value. The re-feeding speed (Q3'-3) of the fuel (5) in the catalyst warming process (S3 ') of the restarted warm-up process is higher than the initial increase supply speed (Q3-1) of the first warm-up process. Is also set to a value higher than the initial post-feeding speed (Q3-3). The supply rate (Q6) at the time of DPF regeneration at the time of DPF regeneration is lower than the initial increase supply rate (Q3-1) of the initial warm-up process, and from the initial post-supply rate (Q3-3) and the resupply rate (Q6). Is also set to a high value. Similarly, the supply speed at the time of DOC regeneration at the time of DOC regeneration is also lower than the initial increased supply speed (Q3-1) of the initial warm-up process, and the post-initial supply speed (Q3-3) and the resupply speed (Q6). Set to a higher value.

The flow of control by the control device (3) is as follows.
As shown in FIG. 3, it is determined in step (S1) whether or not the regeneration requirement condition of the exhaust purification unit (1) is satisfied.
If the determination in step (S1) is negative, step (S1) is repeated, and if the determination is affirmative, warm-up processing of the gas generation catalyst (4) is started, and gas generation is performed in step (S2). The heating process of the catalyst (4) is performed, the catalyst combustion temperature raising process of the gas generating catalyst (4) is performed in step (S3), the warm-up determination process is performed in step (S4), and the catalyst warm-up determination is successful. In the case of the warm-up success determination in which it is determined whether the condition is satisfied and the determination is affirmative, the warm-up process is terminated, the process proceeds to step (S5), and the warm-up failure determination in which the determination is negative or In the case of the warm-up failure prediction determination, the warm-up process is restarted, the gas generating catalyst (4) is heated in step (S2 ′), and the gas generating catalyst (4) catalyst in step (S3 ′). A combustion temperature raising process is performed, and the process proceeds to step (S4).

  In step (S5) of FIG. 3, a reproduction target discrimination process is performed. In this determination process, it is determined whether or not the regeneration request condition for the DPF (11) is satisfied. If the determination is affirmative, regeneration of the DPF (11) is confirmed, and in step (S6), the DPF (11 ) Is performed, and it is determined in step (S7) whether or not the DPF (11) regeneration end condition is satisfied. If the determination is affirmative, the control is terminated and the determination is denied. If so, the process returns to step (S6). If the determination in step (S5) is negative, the reproduction of DOC (12) is confirmed, the reproduction process of DOC (12) is performed in step (S8), and DOC (12) is performed in step (S9). It is determined whether or not the reproduction end condition is satisfied, and if the determination is affirmative, the control is terminated, and if the determination is negative, the process returns to step (S8).

The regeneration requirement condition of the exhaust gas purification unit (1) shown in step (S1) of FIG. 3 is established when the estimated PM accumulated amount of the exhaust gas purification unit (1) reaches the regeneration required value as shown in FIG. To do. When this regeneration request condition is satisfied, it is not determined whether the target of the regeneration request is DPF (11) or DOC (12), and this determination is performed in a later step (S5).
The PM accumulation amount estimation value is estimated by the PM accumulation amount estimation device (20) based on the exhaust pressure upstream of the DOC (12). The exhaust pressure is detected by an exhaust pressure detection device (21). The PM deposition estimation device (20) is an arithmetic processing unit of the control device (3).

The details of the heat treatment of the gas generating catalyst (4) in the first warm-up process of step (S2) in FIG. 3 are as follows.
As shown in FIG. 4A, in step (S2-1), the heating time (t2) is set based on the temperature (T3) of the gas generating catalyst (4). In this step (S2-1), the lower the gas generation catalyst temperature (T3), the longer the heating time (t2) is set. In step (S2-2), heating is started. In step (S2-3), it is determined whether or not the heating time (t2) has elapsed. If the determination is affirmative, step (S2-4) ), The heating is completed, the process proceeds to step (S3-1), and if the determination is negative, step (S2-3) is repeated.

The details of the heating process of the gas generating catalyst (4) in the restarted warm-up process in step (S2 ′) of FIG. 3 are as follows.
As shown in FIG. 4B, in step (S2′-1), the heating time (t2 ′) is set based on the temperature (T3) of the gas generating catalyst (4). In this step (S2′-1), the heating time (t2 ′) is set longer as the gas generating catalyst temperature (T3) is lower. In step (S2′-2), heating is started. In step (S2′-3), it is determined whether or not the heating time (t2 ′) has elapsed, and if the determination is affirmative, step ( In S2′-4), the heating is completed, and the process proceeds to Step (S3′-3). If the determination is negative, Step (S2′-3) is repeated.

Details of the catalyst combustion temperature raising process of the gas generating catalyst (4) in the first warm-up process of step (S3) in FIG. 3 are as follows.
As shown in FIG. 5A, in step (S3-1), air (17) and fuel (5) are initially supplied, and the initial increase supply speed of fuel (5) is (Q3-1). In step (S3-2), it is determined whether or not the initial increase supply time (t3) has elapsed. If the determination is affirmative, air (17) and fuel (5) are determined in step (S3-3). ) Is supplied after the initial stage, the initial post-supply speed of the fuel (5) is set to (Q3-3), the process proceeds to step (S4-1), and the determination in step (S3-2) is negative. Returns to step (S3-1).
The initial increase supply rate of fuel (5) is (Q3-1), and the post-initial supply rate is higher than (Q3-3).

Details of the catalyst combustion temperature raising process of the gas generating catalyst (4) in the restarted warm-up process in step (S3 ′) of FIG. 3 are as follows.
As shown in FIG. 5B, in step (S3′-3), air (17) and fuel (5) are resupplied, and the resupply speed of fuel (5) is (Q3′-3). The process proceeds to step (S4-1).

Details of the warm-up determination process in step (S4) in FIG. 3 are as follows.
As shown in FIG. 6, in step (S4-1) shifted from step (S3-3) or step (S3′-3), the temperature (T3) of the gas generation catalyst (4) is determined as the warm-up determination temperature (T4). -1) is determined, and in the case of a warm-up success determination in which the determination is affirmative, the warm-up process is terminated, and the process proceeds to step (S5).
If the determination in step (S4-1) is negative, it is determined whether or not the warm-up failure determination time (t4-2) has been reached in step (S4-2), and the determination is affirmative. In the case of failure determination, the warm-up process is restarted and the process proceeds to step (S2′-1).
If the determination in step (S4-2) is negative, it is determined in step (S4-3) whether or not the warm-up failure prediction determination time (t4-3) has been reached, and the determination is affirmed. In step (S4-4), it is determined whether or not the temperature (T3) of the gas generation catalyst (4) has dropped from the peak temperature P by the warm-up failure prediction determination temperature (T4-4) or more, and the determination is affirmed. In the case of the warm-up failure prediction determination, the warm-up process is resumed, and the process proceeds to step (S2′-1). If the determination in step (S4-3) is negative, and the determination in step (S4-4) is negative, both return to step (S4-1).
The decrease in temperature (T3) in step (S4-4) may be a continuous decrease or a decrease while moving up and down.

In the reproduction target determination process in step (S5) of FIG. 3, as shown in FIG. 7, a determination is made based on an interval (22) from the end of the previous reproduction to the establishment of the current reproduction request condition, and this interval (22 ) Is equal to or longer than the predetermined time, the regeneration condition for the DPF (11) is satisfied, and the regeneration process for the DPF (11) is confirmed. If the time is less than the predetermined time, the regeneration condition for the DPF (11) is not satisfied. The DOC (12) playback condition is satisfied, and the DOC (12) playback process is finalized.
The regeneration condition of the DPF (11) is satisfied when the estimated PM accumulation value of the DPF (11) reaches the regeneration necessary value. The regeneration condition of the DOC (12) is established when the estimated PM deposition value of the DOC (12) reaches the regeneration necessary value.
The PM deposited on the DPF (11) is almost entirely incinerated and removed by one regeneration process of the DPF (11) and one regeneration process of the DOC (12), but the PM deposited on the DOC (12) In addition, since the incineration removal is not performed even in the regenerating process of the DPF (11) multiple times, and the accumulation is gradually accumulated, if the interval (22) is less than a predetermined time, the regeneration condition of the DOC (12) is satisfied, and the interval is predetermined. If it is more than the time, it can be estimated that the regeneration condition of the DPF (11) is satisfied.

The details when the regeneration process of the DPF (11) in step (S6) of FIG. 3 is performed (S6) are as follows.
When the inlet temperature (T1) of the DOC (12) shown in FIG. 1 does not reach the activation temperature of the DOC (12) due to the light load operation, the controller (3) causes the combustible gas in the ignition device (13). (6) is ignited, the temperature of the exhaust (8) is raised by flame combustion of the combustible gas (6), the DOC (12) is warmed up by the heated exhaust (8), and the DOC (12) When the inlet temperature (T1) of the gas reaches the activation temperature of the DOC (12), the flame combustion of the combustible gas (6) is blown out, the combustible gas (6) is combusted by the DOC (12), and the exhaust gas is exhausted. The temperature of (8) is raised, and PM accumulated in the DPF (11) is incinerated and removed by the heated exhaust (8).

When the flame combustion of the combustible gas (6) is blown out and the catalytic combustion of the combustible gas (6) is generated by the DOC (12), the control device (3) does not cause the flame combustion to occur. The air / fuel mixture (18) producing the combustible gas (6) is adjusted to reduce the air ratio. By doing so, the decrease in the primary air (17) reduces the catalytic reaction temperature in the combustible gas generating catalyst (4), generating a relatively high molecular weight combustible gas (6), and suppressing flame combustion. The flame combustion is blown off by the combustible gas (6), a high amount of heat is generated by the catalytic combustion, and the regeneration of the DPF (11) is promoted.
An ignition detection device (26) is disposed downstream of the ignition device (13), and the presence or absence of ignition of the combustible gas (6) is detected. When the required ignition is not performed, the control device (3) The air ratio of the air-fuel mixture (18) that generates the combustible gas (6) is adjusted to increase. In this way, the increase in the primary air (17) raises the catalytic reaction temperature in the combustible gas generating catalyst (4), generates a combustible gas (6) having a relatively small molecular weight, and promotes flame combustion. Necessary ignition is made.
In addition, since a lot of oxygen is required for the flame combustion and catalytic combustion of the combustible gas (6), the secondary air (27) is mixed in the combustible gas (6).

The details when the reproduction process of the DOC (12) in step (S8) of FIG. 3 is performed (S8) are as follows.
When the inlet temperature (T1) of the DOC (12) shown in FIG. 1 does not reach the regeneration required temperature of the DOC (12), the controller (3) ignites the combustible gas (6) by the ignition device (13). Then, the temperature of the exhaust (8) is raised by flame combustion of the combustible gas (6), and the PM deposited on the DOC (12) is burned and removed by the heated exhaust (8).
In the regeneration process of the DOC (12), the air ratio of the air-fuel mixture (18) that generates the combustible gas (6) is increased by the control device (3) than in the regeneration process of the DPF (11). To be adjusted. In this way, the increase in the primary air (17) raises the catalytic reaction temperature in the combustible gas generating catalyst (4), generates a combustible gas (6) having a relatively small molecular weight, and promotes flame combustion. The When the ignition is not performed, the air ratio of the air-fuel mixture (18) that generates the combustible gas (6) is adjusted to be further increased. In this way, the increase in the primary air (17) further increases the catalytic reaction temperature in the combustible gas generating catalyst (4), generating a combustible gas (6) having a relatively low molecular weight, and promoting flame combustion. And necessary ignition is performed.
In addition, since a lot of oxygen is required for flame combustion of combustible gas (6), secondary air (27) is mixed in combustible gas (6).

The regeneration termination condition of the DPF (11) in step (S7) of FIG. 3 is that the DPF (11) inlet temperature (T1) and the DPF (11) outlet temperature (T2) are equal to or higher than a predetermined temperature and a predetermined time has elapsed. To establish. The regeneration termination condition of the DOC (12) in step (S9) is satisfied when the inlet exhaust temperature (T0) of the DOC (12) is equal to or higher than a predetermined temperature and a predetermined time has elapsed.
The inlet exhaust temperature (T0) of the DOC (12) is detected by the DOC inlet temperature detector (23), the inlet exhaust temperature (T1) of the DPF (11) is detected by the DPF inlet temperature detector (24), and the DPF ( The outlet exhaust temperature (T2) of 11) is detected by the DPF outlet temperature detector (25).

(1) Exhaust gas purification unit
(2) Combustible gas generator
(3) Control device
(4) Combustible gas generation catalyst
(5) Fuel
(6) Combustible gas
(7) Exhaust route
(8) Exhaust
(9) Heater
(S2) Heat treatment
(S2-1) Set the heating time
(S2 ') Heat treatment
(S2'-1) Heating time is set
(S3) Catalyst combustion heating process
(S3 ') Catalyst combustion temperature rise process
(S3'-3) Fuel resupply process
(S4) Warm-up determination process
(S6) DPF regeneration process implemented
(S8) DOC playback process implemented
(t2) Heating time
(T3) Temperature of combustible gas generation catalyst
(T4-1) Warm-up determination temperature
(t4-2) Warm-up failure judgment
(t4-3) During warm-up failure prediction judgment
(T4-4) Failure prediction judgment temperature
(P) Peak temperature
(Q3-1) Initial increase supply speed
(Q3-3) Supply speed after initial stage
(10) Catalyst temperature detector
(11) DPF
(12) DOC
(13) Ignition device
(28) Temperature sensor
(29) Engine cooling water

Claims (10)

It has an exhaust purification section (1), a combustible gas generator (2), and a control device (3).
When regeneration processing of the exhaust gas purification unit (1) is performed (S6) (S8) under the control of the control device (3), fuel is supplied to the combustible gas generating catalyst (4) of the combustible gas generator (2). In an exhaust treatment apparatus for an engine configured to increase the temperature of the exhaust (8) by combustion of the generated combustible gas (6),
Before the regeneration process is performed (S6) (S8), a warm-up process of the combustible gas generating catalyst (4) is performed under the control of the control device (3),
This warm-up process includes a heating process (S2) (S2 '), a subsequent catalyst combustion temperature raising process (S3) (S3'), and a warm-up determination process (S4), and the catalyst combustion temperature raising process (S3) (S3). In ′), the fuel (5) is supplied to the combustible gas generating catalyst (4), and the temperature (T3) of the combustible gas generating catalyst (4) is increased by the catalytic combustion of the fuel (5), so In the case of the warm-up failure determination in the machine determination process (S4), the catalyst combustion temperature raising process (S3) (S3 ') is terminated, and the warm-up process starting from the heating process (S2') is resumed. Composed of
In the catalyst warming process (S3) of the initial warm-up process, the initial fuel increase supply rate (Q3-1) of the initial fuel increase supply process (S3-1) is the subsequent post-initial fuel supply process (S3-3). An exhaust treatment apparatus for an engine, characterized in that it is set to a value higher than the initial fuel supply speed (Q3-3). The engine exhaust treatment apparatus according to claim 1,
In the restarted catalyst combustion temperature raising process (S3 ') of the warm-up process, the fuel re-supply process (S3'-3) not accompanied by the initial fuel increase supply process is performed. apparatus. The engine exhaust treatment apparatus according to claim 2,
The fuel resupply speed (Q3'-3) of the fuel resupply process (S3'-3) is based on the initial fuel supply speed (Q3-3) of the initial warmup process after the initial fuel supply process (S3-3). An exhaust treatment device for an engine, characterized by being set to a high value. The engine exhaust treatment apparatus according to any one of claims 1 to 3,
A temperature sensor (28) is provided, and the temperature sensor (28) is linked to the control device (3), and any one of engine cooling water (29), engine oil, engine wall, and fuel (5) is detected by the temperature sensor (28). The controller (3) is configured to set the target value of the fuel initial increase supply rate (Q3-1) in the first warm-up process to a higher value as the detected temperature is lower. An exhaust processing apparatus for an engine, characterized by comprising: The engine exhaust treatment apparatus according to any one of claims 1 to 4,
In the warm-up determination process (S4), it is determined whether or not the temperature (T3) of the combustible gas generation catalyst (4) has reached a predetermined warm-up determination temperature (T4-1). An exhaust processing apparatus for an engine, characterized in that a warm-up failure determination is made if the determination is negative until a warm-up failure determination time (t4-2) after a lapse of time. The engine exhaust treatment apparatus according to claim 5,
The warm-up prediction process is performed in the warm-up determination process (S4). In this warm-up prediction determination, the warm-up prediction after a predetermined time has elapsed from the occurrence of the peak temperature (P) of the combustible gas generation catalyst (4). At the time of machine prediction determination (t4-3), it is determined whether or not the temperature of the combustible gas generation catalyst (4) has dropped from the peak temperature (P) by a predetermined warm-up failure prediction determination temperature (T4-4) or more. In the case of the warm-up failure prediction determination in which the determination is affirmative, the catalyst combustion temperature raising process (S3) is terminated, and the warm-up process starting from the heating process (S2 ') is performed at the time of the warm-up failure determination ( An exhaust processing apparatus for an engine, which is configured to be restarted at a time earlier than t4-2). The engine exhaust treatment apparatus according to any one of claims 1 to 6,
A catalyst temperature sensor (10) for the combustible gas generating catalyst (4);
Based on the temperature (T3) of the combustible gas generating catalyst (4) before the heat treatment detected by the catalyst temperature sensor (10), the control device (3) performs the first warm-up heat treatment (S2). The heating time (t2) is set (S2-1), and the heating time (t2 ') of the restarted warm-up process (S2') is also before the heating process (S2) first performed before the restart. An exhaust treatment apparatus for an engine, characterized in that it is set based on the temperature (T3) of the combustible gas generating catalyst (4). The engine exhaust treatment apparatus according to any one of claims 1 to 7,
The exhaust purification section (1) includes a DPF (11),
An exhaust processing apparatus for an engine, characterized in that the PM accumulated in the DPF (11) is combusted and removed in the regeneration process of the DPF (11). The engine exhaust treatment apparatus according to any one of claims 1 to 8,
The exhaust purification section (1) has a DOC (12),
An exhaust processing apparatus for an engine, characterized in that, in the regeneration processing of the DOC (12), PM deposited on the DOC (12) is incinerated and removed. The engine exhaust treatment apparatus according to any one of claims 1 to 9,
An ignition device (13) for combustible gas (6) is provided, and an exhaust purification unit (1) is provided with a DOC (12).
The ignition device (13) is arranged on the exhaust upstream side of the DOC (12), ignited by the combustible gas (6) by the ignition device (13), and the temperature of the exhaust (8) by flame combustion of the combustible gas (6). An exhaust processing apparatus for an engine, characterized in that the temperature of the engine is increased.

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