Method and system for maintaining a dfso

Abstract

The present application provides methods and systems for controlling the length of a DFSO. In one example, the method includes adjusting the length of the DFSO based on particulate filter temperature changes.

Description

technical field [0001] The present description generally relates to methods and systems for controlling a vehicle engine to perform particulate filter regeneration during deceleration fuel cutoff (DFSO). Background technique [0002] Exhaust aftertreatment devices may be used to treat exhaust from internal combustion engines. In particular, emission treatment devices may include particulate filters, oxidation catalysts, and nitrogen oxide (NOx) catalysts. Particulate matter consists primarily of underburned carbon particles, which may become trapped in the particulate filter and may gradually restrict the flow of exhaust gas as the particulate matter accumulates in the particulate filter. In order to periodically regenerate or clean the filter of particulate matter, measures may be taken to cause the temperature of the exhaust gas to increase above a predetermined level (eg, above 450° C.) in order to burn off the carbon particles accumulated in the filter. [0003] In som...

AI Technical Summary

Problems solved by technology

For example, the soot load on a particulate filter can be difficult to estimate due to the accumulated ash load

Ash loading can artificially increase the estimated soot loading by increasing exhaust backpressure, where this increase is mistaken for an increase in soot, resulting in increased estimates of particulate matter reaction rates and unnecessary reductions in DFSO length

Thus, DFSO particulate filter regeneration may be unnecessarily limited to protect the particulate filter from combustion of non-existent soot loads

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