METHODS AND SYSTEMS FOR AN INTAKE OXYGEN SENSOR
First Claim
1. A method for an engine, comprising:
- in response to ingestion of purge or crankcase hydrocarbons during EGR flow,increasing a reference voltage applied to an intake manifold oxygen sensor; and
adjusting EGR flow to the engine based on an output of the sensor at the increased reference voltage.
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Accused Products
Abstract
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.
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Citations
20 Claims
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1. A method for an engine, comprising:
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in response to ingestion of purge or crankcase hydrocarbons during EGR flow, increasing a reference voltage applied to an intake manifold oxygen sensor; and adjusting EGR flow to the engine based on an output of the sensor at the increased reference voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for an engine, comprising:
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during a first EGR condition, estimating EGR based on an intake manifold oxygen sensor operating at a higher reference voltage; and during a second EGR condition, estimating EGR based on the intake manifold oxygen sensor operating at a lower reference voltage. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An engine system, comprising:
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an engine including an intake manifold and a crankcase; a turbocharger with an intake compressor, an exhaust turbine, and a charge air cooler; an intake throttle coupled to the intake manifold downstream of the charge air cooler; a canister configured to receive fuel vapors from a fuel tank, the canister coupled to the intake manifold; an EGR system including a passage for recirculating exhaust residuals from downstream of the turbine to upstream of the compressor via an EGR valve; an oxygen sensor coupled to the intake manifold, downstream of the charge air cooler and upstream of the intake throttle; and a controller with computer readable instructions for; adjusting a reference voltage applied to the oxygen sensor based on one of purging conditions and crankcase ventilation conditions being met; estimating an intake EGR dilution based on an output of the oxygen sensor; and adjusting an opening of the EGR valve based on the estimated intake EGR dilution. - View Dependent Claims (19, 20)
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Specification