Method for controlling transitions between operating modes of an engine for rapid heating of an emission control device

• US 20030221417A1
• Filed: 06/04/2002
• Published: 12/04/2003
• Est. Priority Date: 06/04/2002
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Surnilla, Gopichandra
• Granted Patent: US 6,868,827 B2
• Time in Patent Office: Days
• US Class Current: 60/284
• CPC Class Codes: F01N 11/007 the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 13/011 having two or more purifying devices arranged in parallel
• CPC Class Codes: F01N 13/107 More than one exhaust manifold or exhaust collector
• CPC Class Codes: F01N 2430/06 by varying fuel-air ratio, e.g. by enriching fuel-air mixture
• CPC Class Codes: F01N 2430/08 by modifying ignition or injection timing
• CPC Class Codes: F01N 2560/026 for measuring or detecting NOx
• CPC Class Codes: F01N 3/2006 Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/2046 Periodically cooling catalytic reactors
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/027 to purge or regenerate the exhaust gas treating apparatus
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F02P 5/1512 with particular means concerning an individual cylinder
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

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.

Claims

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 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;

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.

2. The method recited in claim 1 wherein said third advancing further comprises advancing both said first and second ignition timing to a preselected ignition timing.

3. The method recited in claim 1 wherein said first ignition timing is retarding from a maximum torque timing;

and wherein during said first, second, and third operations, disabling engagement, or disengagement, of an air conditioning compressor.

4. The method recited in claim 1 wherein said second retarding said first ignition timing while advancing said second ignition timing further comprises retarding said first ignition timing and advancing said second ignition timing such that an engine torque decrease caused by said retarding is cancelled by an engine torque increase caused by said advancing.

5. The method recited in claim 1 wherein said operation in said first mode is in response to an engine start to light-off the emission control device.

6. The method recited in claim 1 further comprising further adjusting engine airflow to provide a desired engine output.

7. The method recited in claim 1 further comprising further adjusting engine airflow to provide a desired engine output torque.

8. 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.

9. The method recited in claim 8 wherein said airflow is adjusted via an electronically controlled throttle valve.

10. The method recited in claim 8 wherein said predetermined ignition timing is retarded from optimal timing.

11. The method recited in claim 8 wherein said second operating mode is requested after an engine cold start to increase catalyst temperature.

12. 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 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.

13. The method recited in claim 12 wherein said first timing is retarded from optimal torque timing.