Engine fueling control for catalyst desulfurization
AssigneeFord Global Technologies, LLC
InventorGopichandra Surnilla
Life of this patent
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Abstract
A method is described for controlling decontamination of an emission control device. Temperature of the emission control device is maintained at a desired temperature by operating some cylinders of the engine lean and others rich. These lean and rich mixtures react exothermically in the exhaust gas and in the emission control device to generate heat. Efficient contaminant removal is obtained by oscillating the mixture air-fuel ratio about stoichiometry. This oscillation is provided by adjusting the fuel provided to the rich cylinders, or by adjusting the air provided to the lean cylinders, thereby minimizing any torque disturbance corresponding to the oscillations in exhaust air-fuel ratio.
Claims21
A method for controlling an engine having a first and second group of cylinders, both of which are coupled to an emission control device, the method comprising:
- operating the first group on average at a first lean air-fuel ratio;
- operating the second group at a second air-fuel ratio;
- and
- adjusting said second air-fuel ratio based on a condition in or downstream of the emission control device by controlling fuel injected into the second group to cause a mixture air-fuel ratio of a mixture of gasses from the first and second group to oscillate around a predetermined air-fuel ratio.
A method for controlling an engine having a first and second group of cylinders, both of which are coupled to an emission control device, the method comprising:
- indicating emission control device temperature has reached a predetermined temperature;
- and
- in response to said indication:
- operating the first group on average at a first lean air-fuel ratio;
- operating the second group at a second air-fuel ratio;
- and
- adjusting said second air-fuel ratio by controlling fuel injected into the second group to cause a mixture air-fuel ratio of a mixture of gasses from the first and second group to oscillate around predetermined air-fuel ratio to thereby efficiently remove sulfur compounds from the emission control device.
A method for controlling an engine having a first and second group of cylinders, both of which are coupled to an emission control device, the method comprising:
- operating the first group on average at a first lean air-fuel ratio;
- operating the second group at a second air-fuel ratio;
- adjusting only said second air-fuel ratio to cause a mixture air-fuel ratio of a mixture of gasses from the first and second group to oscillate around a predetermined air-fuel ratio, said adjustment of said second air-fuel ratio being based on a condition in or downstream of the emission control device that is based on information from an air-fuel ratio sensor coupled downstream of the emission control device;
- and
- adjusting both said first and second air-fuel ratio by adjusting either injected fuel or engine airflow so that engine output approaches a desired engine output.
A method for controlling an engine having a first and second group of cylinders, both of which are coupled to an emission control device, the method comprising:
- operating the first group on average at a first rich air-fuel ratio;
- operating the second group at a second air-fuel ratio;
- and
- adjusting said second air-fuel ratio by controlling air entering the second group to cause a mixture air-fuel ratio of a mixture of gasses from the first and second group to oscillate around predetermined air-fuel ratio based on a sensor coupled downstream of the emission control device.
A system, comprising:
- an engine having a first group of cylinders and a second group of cylinders;
- an emission control device coupled to the first group and to the second group;
- a first actuator coupled to the first group for adjusting at least one of an intake or exhaust valve of the first group of cylinders;
- a second actuator coupled to the second group for adjusting at least one of an intake or exhaust valve of the second group of cylinders;
- and
- a controller for operating said first group a first rich air-fuel ratio, operating said second group at a second lean air-fuel ratio by adding additional air compared with said first group by adjusting said second actuator to a position different than said first actuator, and modifying said first rich air-fuel ratio by adjusting fuel injected into said first cylinder group.
A method for controlling an engine having a first and second group of cylinders, both of which are coupled to an emission control device, the method comprising:
- operating the first group at a first lean air-fuel ratio;
- operating the second group at a second rich air-fuel ratio;
- and
- controlling fuel injected into the first group of cylinders to be a different amount than fuel injected into the second group of cylinders based on a condition in or downstream of the emission control device to cause a mixture air-fuel ratio of a mixture of gasses from the first second group to oscillate around a predetermined air-fuel ratio.
Dependencies are inferred from the claim text.