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 having 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 group of cylinders at a first ignition timing and the second group of cylinders at a second ignition timing more retarded than said first ignition timing;
in response to a request for operating in another operating mode;
first decreasing engine airflow while advancing said first ignition timing;
second retarding said first ignition timing while advancing said second ignition timing; and
third advancing both said first and second ignition timing while decreasing 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
7 Claims
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1. A method for controlling an engine having 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 group of cylinders at a first ignition timing and the second group of cylinders at a second ignition timing more retarded than said first ignition timing;
in response to a request for operating in another operating mode;
first decreasing engine airflow while advancing said first ignition timing;
second retarding said first ignition timing while advancing said second ignition timing; and
third advancing both said first and second ignition timing while decreasing engine airflow. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification