Air/fuel imbalance detection system and method
First Claim
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1. A method for detecting emissions from an internal combustion engine comprising:
- determining a reference air/fuel mixture signal based on an engine speed and an airflow into the engine;
determining an actual air/fuel mixture signal from an air/fuel mixture sensor;
comparing said reference air/fuel mixture signal to said actual air/fuel mixture signal;
determining whether an air/fuel imbalance condition occurs based on said comparison; and
setting a service indicator based on said determination of whether said air/fuel imbalance condition occurred.
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Abstract
A method for detecting emissions from an internal combustion engine generally including determining a reference air/fuel mixture signal based on an engine speed and an airflow into the engine. The method includes determining an actual air/fuel mixture signal from an air/fuel mixture sensor and comparing the reference air/fuel mixture signal to the actual air/fuel mixture signal. The method also includes determining whether an air/fuel imbalance condition occurs based on the comparison and setting a service indicator based on the determination of whether the air/fuel imbalance condition occurred.
52 Citations
23 Claims
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1. A method for detecting emissions from an internal combustion engine comprising:
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determining a reference air/fuel mixture signal based on an engine speed and an airflow into the engine; determining an actual air/fuel mixture signal from an air/fuel mixture sensor; comparing said reference air/fuel mixture signal to said actual air/fuel mixture signal; determining whether an air/fuel imbalance condition occurs based on said comparison; and setting a service indicator based on said determination of whether said air/fuel imbalance condition occurred. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for detecting emissions from an internal combustion engine comprising:
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determining a reference oxygen concentration signal based on an engine speed and an airflow into the engine; determining an actual oxygen concentration signal based on an oxygen concentration sensor; comparing said reference oxygen concentration signal to said actual oxygen concentration signal, wherein said comparison includes comparing a trace length of said reference oxygen concentration signal to a trace length of said actual oxygen concentration signal; and determining whether an air/fuel imbalance condition occurs when said trace length of said actual oxygen concentration signal is greater than said trace length of said actual oxygen concentration signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An air/fuel imbalance detection system comprising:
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an engine having at least one cylinder that produces combustion gases; an exhaust manifold connected to said at least one cylinder; an air/fuel mixture sensor connected to said exhaust manifold that samples said combustion gases; and a control module that determines a reference air/fuel mixture signal based on an engine speed and an airflow into said engine, that determines an actual air/fuel mixture signal based from said air/fuel mixture sensor that compares said reference air/fuel mixture signal to said actual air/fuel mixture signal, that determines whether an air/fuel imbalance condition occurs based on said comparison, and that sets a service indicator based on said determination of whether said air/fuel imbalance condition occurred. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification