Method for controlling transitions between operating modes of an engine for rapid heating of an emission control device
First Claim
1. A method for controlling an engine have at least first and second groups of cylinders, the engine coupled to an emission control device, comprising:
- operating the engine in a first mode with the first and second group of cylinders at a predetermined ignition timing;
in response to a request for operating in a second operating mode where the first group of cylinders is operated at a first ignition timing and the second group of cylinders is operated at a second ignition timing more retarded than said first ignition timing;
advancing said first ignition timing while retarding said second ignition timing; and
then third retarding both said first and second ignition timing while increasing engine airflow.
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Accused Products
Abstract
A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.
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Citations
6 Claims
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1. A method for controlling an engine have at least first and second groups of cylinders, the engine coupled to an emission control device, comprising:
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operating the engine in a first mode with the first and second group of cylinders at a predetermined ignition timing;
in response to a request for operating in a second operating mode where the first group of cylinders is operated at a first ignition timing and the second group of cylinders is operated at a second ignition timing more retarded than said first ignition timing;
advancing said first ignition timing while retarding said second ignition timing; and
then third retarding both said first and second ignition timing while increasing engine airflow. - View Dependent Claims (2, 3, 4)
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5. A method for controlling an engine have at least first and second groups of cylinders, the engine coupled to an emission control device, comprising:
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operating the engine in a first mode with the first and second group of cylinders at substantially the same ignition;
in response to a request for operating in a second operating mode where the first group of cylinders is operated at a first ignition timing and the second group of cylinders is operated at a second ignition timing more retarded than said first ignition timing;
first increasing engine airflow while retarding both said first and second ignition timing;
second advancing said first ignition timing while retarding said second ignition timing; and
third retarding both said first and second ignition timing while increasing engine airflow. - View Dependent Claims (6)
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Specification