DPF REGENERATION CONTROL DEVICE

• US 20160222900A1
• Filed: 09/08/2014
• Published: 08/04/2016
• Est. Priority Date: 09/27/2013
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries Engine & Turbocharger, Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Nishizawa, Kazuki, Yamada, Tomohide, Sato, Daisuke
• Granted Patent: US 9,719,440 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01N 2560/06 the means being a temperature sensor
• CPC Class Codes: F01N 2560/14 having more than one sensor of one kind
• CPC Class Codes: F01N 2900/1602 Temperature of exhaust gas apparatus
• CPC Class Codes: F01N 2900/1606 Particle filter loading or soot amount
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/0253 adding fuel to exhaust gases
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F02D 41/024 to increase temperature of the exhaust gas treating apparatus
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: F02D 41/405 with post injections
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An object is to provide a DPF regeneration control device whereby it is possible to prevent clogging of a DOC more efficiently than conventional techniques, and to recover the DOC securely from a clogging condition even if the DOC is actually clogged. A DPF regeneration control device (10) includes: a DPF temperature-increase unit (10A) including a first temperature-increase unit (12) configured to heat a DPF (37) to a predetermined temperature, and a second temperature-increase unit (14) configured to heat the DPF to a temperature higher than the predetermined temperature in cooperation with the first temperature-increase unit; a DOC clogging detection unit (10D) configured to detect that a DOC (35) is clogged if a clogging parameter detected during execution of the automatic regeneration exceeds a clogging threshold value determined in advance for a predetermined period, the clogging parameter being related to clogging of the DOC, and a DOC clogging countermeasure unit (10C) configured to stop the automatic regeneration and issue an alert to prompt execution of the manual regeneration, if the clogging of the DOC is detected.

Claims

1. A DPF regeneration control device, provided for an exhaust-gas processing device of a diesel engine, the exhaust-gas processing device including a DOC disposed in an exhaust channel and a DPF disposed on a downstream side of the DOC, for controlling execution of forced regeneration of heating the DPF to remove PM which accumulates on the DPF, the forced regeneration comprising automatic regeneration automatically executed if a predetermined forced-regeneration execution condition is satisfied, and manual regeneration executed by manual operation to heat the DPF to a higher temperature than in the automatic regeneration, and the DPF regeneration device comprising:

a DPF temperature-increase unit including a first temperature-increase unit configured to heat the DPF to a predetermined temperature, and a second temperature-increase unit configured to heat the DPF to a temperature higher than the predetermined temperature in cooperation with the first temperature-increase unit;

a DOC clogging detection unit configured to detect that the DOC is clogged if a clogging parameter detected during execution of the automatic regeneration exceeds a clogging threshold value determined in advance for a predetermined period, the clogging parameter being related to clogging of the DOC; and

a DOC clogging countermeasure unit configured to stop the automatic regeneration and issue an alert to prompt execution of the manual regeneration, if the clogging of the DOC is detected.

2. The DPF regeneration control device according to claim 1, further comprising:

a DOC clogging initial stage detection unit configured to detect that the DOC is in an initial stage of the clogging if the clogging parameter detected during execution of the automatic regeneration is not greater than the clogging threshold value and greater than a second clogging threshold value smaller than the clogging threshold value for a predetermined period, or if the clogging parameter is not greater than the clogging threshold value and a change amount of the clogging parameter is greater than a change-amount threshold value set in advance for a predetermined period; and

a DOC clogging initial stage countermeasure unit configured to operate the first temperature-increase unit for a predetermined period after completion of the automatic regeneration if the DOC is detected to be in the initial stage of the clogging.

3. The DPF regeneration control device according to claim 1, further comprising:

a DOC clogging dangerous state detection unit configured to detect that the DOC is in a clogging dangerous state if the diesel engine is under an operation state in which clogging of the DOC is likely to occur during normal operation in which none of the forced regenerations, which are the automatic regeneration and the manual regeneration, is executed; and

a DOC clogging dangerous state countermeasure unit configured to operate the first temperature-increase unit for only a predetermined period if the DOC is detected to be in the clogging dangerous state.

4. The DPF regeneration control device according to claim 3,

wherein the DOC clogging dangerous state detection unit is configured to detect that the DOC is in the clogging dangerous state, if one or more of following conditions are satisfied:

a temperature of exhaust gas is not greater than a predetermined temperature continuously for a predetermined period or longer;

the number of times, per unit time, which a change rate of an engine rotation speed of the diesel engine exceeds a predetermined rotation-speed threshold value exceeds a threshold value continuously for a predetermined period or longer; and

a mean value of a PM discharge-amount estimate value is at least a predetermined threshold value continuously for a predetermined period or longer.

5. The DPF regeneration control device according to claim 1,

wherein the first temperature-increase unit comprises at least one of

a throttle valve control unit configured to control an opening degree of a throttle valve disposed in an intake channel,

an early post injection control unit configured to control a fuel injection amount of early post injection of injecting fuel after a time of main combustion injection, or

a rail-pressure control unit configured to control a rail pressure at which the fuel is injected, and

wherein the second temperature-increase unit comprises

a late post injection control unit configured to control a fuel injection amount of late post injection of injecting fuel at a timing which does not contribute to combustion in a combustion chamber after the early post injection, or

an exhaust-duct injection control unit configured to control a fuel injection amount of exhaust-duct injection of injecting fuel to an exhaust channel on an engine downstream side.

6. The DPF regeneration control device according to claim 1,

wherein the clogging parameter is set on the basis of a temperature difference between an inlet temperature of the DPF and an outlet temperature of the DPF.

7. The DPF regeneration control device according to claim 1,

wherein the clogging parameter is set as an outlet temperature of the DPF.

8. The DPF regeneration control device according to claim 5,

wherein the clogging parameter is set on the basis of a temperature difference between an outlet temperature and an inlet temperature of the DOC, a flow rate of exhaust gas flowing through the DOC, and a fuel-injection amount of the late post injection or the exhaust-duct injection.

9. The DPF regeneration control device according to claim 1,

wherein the clogging parameter is set on the basis of an increase speed of an inlet temperature of the DPF, and an increase speed of the inlet temperature of the DPF in an initial state in which the DOC is not clogged.

10. The DPF regeneration control device according to claim 5,

wherein the late post injection control unit or the exhaust-duct injection control unit is configured to control a fuel injection amount so that an inlet temperature of the DPF reaches a target temperature required to execute the forced regeneration, and

wherein the clogging parameter is set

on the basis of a cumulative fuel-injection amount of the late post injection or the exhaust-duct injection of injecting while an inlet temperature of the DPF increases by a predetermined temperature, and a cumulative fuel-injection amount of the late post injection or the exhaust-duct injection of injecting while the inlet temperature of the DPF increases by the predetermined temperature in an initial state in which the DOC is not clogged, or

on the basis of a mean injection amount of the late post injection or the exhaust-duct injection of injecting in a stable state in which the inlet temperature of the DPF has reached a target control temperature, and a mean injection amount of the late post injection or the exhaust-duct injection of injecting in a stable state in which the inlet temperature of the DPF has reached a target control temperature in an initial state in which the DOC is not clogged.

11. The DPF regeneration control device according to claim 5,

wherein the late post injection control unit or the exhaust-duct injection control unit is configured to control a fuel injection amount so that an inlet temperature of the DPF reaches a target temperature required to execute the forced regeneration, and

wherein the clogged parameter comprises at least two of:

a clogging parameter set on the basis of a temperature difference between an inlet temperature of the DPF and an outlet temperature of the DPF;

a clogging parameter set as an outlet temperature of the DPF;

a clogging parameter set on the basis of a temperature difference between an outlet temperature and an inlet temperature of the DOC, a flow rate of exhaust gas flowing through the DOC, and a fuel-injection amount of the late post injection or the exhaust-duct injection;

the clogging parameter set on the basis of an increase speed of the inlet temperature of the DPF, and an increase speed of the inlet temperature of the DPF in an initial state in which the DOC is not clogged; and

a clogging parameter set on the basis of a cumulative fuel-injection amount of the late post injection or the exhaust-duct injection of injecting while an inlet temperature of the DPF increases by a predetermined temperature, and a cumulative fuel-injection amount of the late post injection or the exhaust-duct injection of injecting while the inlet temperature of the DPF increases by the predetermined temperature in an initial state in which the DOC is not clogged, or on the basis of a mean injection amount of the late post injection or the exhaust-duct injection of injecting in a stable state in which the inlet temperature of the DPF has reached a target control temperature, and a mean injection amount of the late post injection or the exhaust-duct injection of injecting in a stable state in which the inlet temperature of the DPF has reached a target control temperature in an initial state in which the DOC is not clogged.