Methods and systems for an intake oxygen sensor

摘要

Methods and systems are provided for adjusting a reference voltage for an intake manifold oxygen sensor based on ingestion of hydrocarbons from a fuel system canister and/or an engine crankcase. During conditions when purge or crankcase ventilation hydrocarbons are ingested in the intake aircharge, the intake oxygen sensor is transitioned from operating at a lower reference voltage to a higher reference voltage where the effects of the ingested hydrocarbons on the sensor output are nullified. An EGR dilution of the intake aircharge is estimated based on the output of the sensor at the higher reference voltage while an amount of hydrocarbons ingested is estimated based on a difference between sensor outputs at the higher and lower reference voltages.

主权项

1. A method for an engine, comprising:
while EGR is flowing,
modulating, via a controller, a reference voltage applied to an intake manifold oxygen sensor;estimating, via the controller, an amount of purge and crankcase ventilation hydrocarbons in the EGR based on output of the intake manifold oxygen sensor received by the controller during the modulating; andadjusting, via the controller, a position of an EGR valve based on the estimated amount of purge and crankcase ventilation hydrocarbons in the EGR.