Individual cylinder air/fuel ratio feedback control system

Claim 1

A method for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising the steps of: sampling the sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; storing each of said N output signals; concurrently reading each of said N output signals from said storage once each output period to define N nonperiodic signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; generating N feedback correction signals from said N nonperiodic signals; and correcting a mixture of air and fuel supplied to each of the cylinders in response to each of said feedback correction signals for achieving a desired air/fuel ratio in each of the cylinders.

Claim 2

A method for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising the steps of: sampling the sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; storing each of said N output signals; concurrently reading each of said N output signals from said storage once each output period to define N nonperiodic signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; generating N feedback correction signals from said N nonperiodic signals; and correcting a mixture of air and fuel supplied to each of the cylinders in response to each of said feedback correction signals for achieving a desired air/fuel ratio in each of the cylinders.

Claim 5

A method for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal, combustion engine, comprising the steps of: delivering a desired fuel charge to each of the cylinders to provide a desired average air/fuel ratio among all the cylinders in response to the oxygen sensor; sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.

Claim 6

A method for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal, combustion engine, comprising the steps of: delivering a desired fuel charge to each of the cylinders to provide a desired average air/fuel ratio among all the cylinders in response to the oxygen sensor; sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.

Claim 9

An apparatus for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising: sampling means for sampling the sensor once each period associated with a combustion event in one of the cylinders to generate and store N output signals; synchronizing means for concurrently reading each of said N output signals once each output period to define N nonperiodic signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; generating means for generating N feedback correction signals from said N nonperiodic signals; and correcting means for correcting a mixture of air and fuel supplied to each of the cylinders in response to each of said feedback correction signals for achieving a desired air/fuel ratio in each of the cylinders.

Claim 10

An apparatus for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising: sampling means for sampling the sensor once each period associated with a combustion event in one of the cylinders to generate and store N output signals; synchronizing means for concurrently reading each of said N output signals once each output period to define N nonperiodic signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; generating means for generating N feedback correction signals from said N nonperiodic signals; and correcting means for correcting a mixture of air and fuel supplied to each of the cylinders in response to each of said feedback correction signals for achieving a desired air/fuel ratio in each of the cylinders.

Claim 13

An apparatus for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising: a first air/fuel controller for adjusting a desired fuel charge delivered to each of the cylinders to provide a desired average air/fuel ratio among all the cylinders in response to the oxygen sensor; sampling means for sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing means for synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and a second air/fuel controller for correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.

Claim 14

An apparatus for correcting air/fuel ratio for each of N cylinders via an oxygen sensor positioned in the exhaust of an internal combustion engine, comprising: a first air/fuel controller for adjusting a desired fuel charge delivered to each of the cylinders to provide a desired average air/fuel ratio among all the cylinders in response to the oxygen sensor; sampling means for sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing means for synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and a second air/fuel controller for correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.

Claim 18

An apparatus for correcting air/fuel ratio of each of N cylinders in an internal combustion engine having an air/fuel intake manifold with N fuel injectors coupled thereto in proximity to the N cylinders, comprising: an exhaust gas oxygen sensor for providing an indication of air/fuel ratio from the engine exhaust; an airflow sensor for providing a measurement of airflow inducted into the engine; first air/fuel control means responsive to both said exhaust gas oxygen sensor and said airflow sensor for providing a fuel demand signal related to a desired average air/fuel ratio among the N cylinders; sampling means for sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing means for synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and a second air/fuel controller for correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.

Claim 19

An apparatus for correcting air/fuel ratio of each of N cylinders in an internal combustion engine having an air/fuel intake manifold with N fuel injectors coupled thereto in proximity to the N cylinders, comprising: an exhaust gas oxygen sensor for providing an indication of air/fuel ratio from the engine exhaust; an airflow sensor for providing a measurement of airflow inducted into the engine; first air/fuel control means responsive to both said exhaust gas oxygen sensor and said airflow sensor for providing a fuel demand signal related to a desired average air/fuel ratio among the N cylinders; sampling means for sampling the oxygen sensor once each period associated with a combustion event in one of the cylinders to generate N output signals; synchronizing means for synchronizing said N output signals once each output period for generating N nonperiodic correction signals each being related to the air/fuel ratio of a corresponding cylinder wherein said output period is defined as a predetermined number of engine revolutions required for each of the cylinders to have a single combustion event; and a second air/fuel controller for correcting said desired fuel charge to generate a separate corrected fuel charge for each of the cylinders in response to each of said correction signals thereby providing a desired air/fuel ratio for each of the cylinders.