Humidity and fuel alcohol content estimation
AssigneeFord Global Technologies, LLC
InventorsGopichandra Surnilla, Richard E. Soltis, Dan A. Makled
Life of this patent
Estimating the term…
Abstract
Methods and systems for an engine system including an exhaust gas sensor are disclosed. In one example, under a first engine fueling condition, an air-fuel ratio correction factor is determined based on an expected air-fuel ratio and an actual air-fuel ratio. During a second engine fueling condition and a third engine non-fueling condition, fuel alcohol content and ambient humidity, respectively, are determined based on the exhaust gas sensor and corrected based on the air-fuel ratio correction factor.
Claims20
A method, comprising:
- during a first engine fueling condition,
- applying a first voltage to an exhaust gas sensor;
- and
- learning an air-fuel ratio correction factor based on a sensor output;
- and
- during a second engine fueling condition following the first condition,
- alternating between applying first and second voltages to the sensor;
- and
- estimating an injected fuel alcohol content based on sensor outputs at the first and second voltages and the learned correction factor.
A method for an engine, comprising:
- applying a first, lower voltage to an exhaust gas sensor during fueled engine operation to learn an error between an expected air-fuel ratio and an actual air-fuel ratio;
- after learning the error,
- sequentially applying each of the first voltage and a second, higher voltage to the sensor during fueled engine operation;
- correcting sensor outputs at the first and second voltages based on the learned error;
- and
- estimating an ethanol content of burned fuel based on the corrected sensor outputs.
A system for controlling an engine in a flex-fuel vehicle, the system comprising:
- an exhaust manifold including an exhaust gas oxygen sensor;
- and
- a controller including a computer readable storage medium comprising instructions for:
- during selected engine fueling conditions,
- applying a first, lower voltage to the sensor and receiving a first pumping current output from the sensor, the first pumping current indicative of an amount of oxygen;
- estimating an exhaust air-fuel ratio based on the first pumping current;
- learning a correction factor based on the estimated exhaust air-fuel ratio relative to an expected air-fuel ratio;
- after the learning,
- applying a second, higher voltage to the sensor and receiving a second pumping current output from the sensor, the second pumping current indicative of an amount of oxygen and water;
- and
- identifying an amount of ethanol in fuel burned in the engine based on the first and second pumping currents and the correction factor.
Dependencies are inferred from the claim text.