Exhaust gas emission control system for diesel engine
AssigneeMitsubishi Heavy Industries, Ltd.
InventorsKo Takayanagi, Keisuke Okuda
Life of this patent
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Abstract
An exhaust gas emission control system for a diesel engine, having an oxidation catalyst (DOC) (7) and a diesel particulate filter (DPF) (9) in an exhaust passage, wherein a late post-injection control unit (62), which injects fuel into a combustion chamber at a timing not contributing to combustion in DPF regeneration control, feedback controls a late post-injection amount such that a regeneration amount of soot regenerated by the DPF (9) becomes a target soot regeneration amount per unit time.
Claims10
An exhaust gas emission control system for a diesel engine as an internal combustion engine, comprising, in an exhaust passage, an oxidation catalyst (DOC) and a diesel particulate filter (DPF) for collecting soot in exhaust gas so that the soot collected by the DPF is regenerated, the exhaust gas emission control system further comprising:
- an electronic control unit;
- and
- a memory storing instructions that, when executed by the electronic control unit, cause the exhaust gas emission control system to:
- control, when an amount of accumulated soot exceeds a predetermined value, a unit to heat the DPF up to near a predetermined target temperature so as to burn and remove the accumulated soot;
- inject fuel into a combustion chamber at a timing not contributing to combustion;
- and
- control a late post-injection amount such that a regeneration amount per unit time of the soot regenerated by the DPF becomes a target soot regeneration amount per unit time,
- wherein the target soot regeneration amount per unit time is varied according to a regeneration elapsed time after the start of late post-injection, such that the target soot regeneration amount per unit time is set to a small value directly after the start of regeneration, then the set value is increased as the regeneration progresses, and the target soot regeneration amount per unit time is set to a small value again at the end of the regeneration.
An exhaust gas emission control system for a diesel engine as an internal combustion engine, comprising, in an exhaust passage, an oxidation catalyst (DOC) and a diesel particulate filter (DPF) for collecting soot in exhaust gas so that the soot collected by the DPF is regenerated, the exhaust gas emission control system further comprising:
- an electronic control unit;
- and
- a memory storing instructions that, when executed by the electronic control unit, cause the exhaust gas emission control system to:
- control, when an amount of accumulated soot exceeds a predetermined value, a unit to heat the DPF up to near a predetermined target temperature so as to burn and remove the accumulated soot;
- inject fuel into a combustion chamber at a timing not contributing to combustion;
- and
- control a late post-injection amount such that a regeneration amount per unit time of the soot regenerated by the DPF becomes a target soot regeneration amount per unit time,
- wherein the target soot regeneration amount per unit time is varied according to an amount of the accumulated soot after the start of late post-injection, such that the target soot regeneration amount per unit time is set to a small value directly after the start of regeneration, then the set value is increased as the regeneration progresses, and the target soot regeneration amount per unit time is set to a small value again at the end of the regeneration.
Dependencies are inferred from the claim text.