Method and system for particulate filter regeneration

Abstract

The present invention relates to a method and a system for particulate filter regulation. Methods and systems are provided for expediting exhaust particulate filter regeneration. In one example, an engine controller may generate an exotherm at the filter by operating engine cylinders with air-fuel imbalance while using electric assist to a turbocharger to meet a torque demand and raise an intake airflow to enhance the effect of the exotherm. Once heated, the filter may be regenerated by flowing extra air to the exhaust via an air pump and injecting extra fuel to an exhaust passage via an exhaust injector.

Description

technical field [0001] The present invention generally relates to methods and systems for effectuating particulate filter regeneration. Background technique [0002] Direct injection engines may provide increased performance so that engine efficiency may be improved. Injecting fuel directly into the cylinder reduces the temperature inside the cylinder so that more air and fuel can be drawn into the cylinder. However, since there is less time to mix the air and fuel, the air-fuel mixture in the cylinder may not completely vaporize when fired at higher engine speeds and loads. As a result, a portion of the injected fuel may be incompletely oxidized, forming carbonaceous soot within the cylinder. After the soot is expelled from the engine, the soot may be stored in the particulate filter for subsequent oxidation. [0003] Some internal combustion engines employ a particulate filter or PF in the exhaust system (e.g., a gasoline particulate filter (GPF) or diesel particulate f...

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Problems solved by technology

Spark retardation alone may not be sufficient to heat the GPF

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