Method to control transitions between modes of operation of an engine

• US 6,735,938 B2
• Filed: 06/04/2002
• Issued: 05/18/2004
• 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
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US10/064,020
• Publication Number:
  US 20030224907A1
• Time in Patent Office: 714 Days
• Field of Search: 602/74, 602/85, 123/399, 123/406.23, 123/406.45, 123/406.47, 123/406.55, 123/481, 123/198.F, 123/443, 477/183, 477/203
• US Class Current: 60/274
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/003 Adding fuel vapours, e.g. drawn from engine fuel reservoir
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent

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 having a first and second group of cylinders, comprising:

operating the engine in a first mode with the first group of cylinders combusting a lean mixture of air and injected fuel at a first ignition timing and the second group of cylinders having substantially no injected fuel;

determining a request to operate in a second mode; and

in response to said request, commencing fuel injection in the second group and performing at least one of the actions selected from the group consisting of;

retarding said first ignition timing of the first cylinder group, and decreasing airflow through the engine.

2. The method recited in claim 1 wherein said request is to purge NOx stored in an emission control device coupled to the engine.

3. The method recited in claim 1 wherein said request is to purge fuel vapors stored in a fuel vapor storage device.

4. The method recited in claim 1 wherein said request is to increase engine output torque.

5. The method recited in claim 1 wherein said request is to increase manifold vacuum.

6. The method recited in claim 1 wherein said request is based on actuation of a brake pedal.

7. The method recited in claim 1 wherein said request is based on a component operating temperature.

8. The method recited in claim 1 wherein in response to said request, both retarding said first ignition timing of the first cylinder group and decreasing airflow through the engine are performed.