Method for rapid catalyst heating

• US 6,868,667 B2
• Filed: 01/28/2003
• Issued: 03/22/2005
• 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): Tran, Binh Q.
• Application Number:
  US10/352,642
• Publication Number:
  US 20030221418A1
• Time in Patent Office: 784 Days
• Field of Search: 602/74, 602/76, 602/85, 602/84, 602/89, 602/90, 123/198.F, 123/443, 123/406.23, 123/406.44, 123/481
• US Class Current: 60/285
• CPC Class Codes: F02D 2200/0804 Estimation of the temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 31/002 controlling air supply
• CPC Class Codes: F02D 31/003 for idle speed control
• CPC Class Codes: F02D 41/003 Adding fuel vapours, e.g. drawn from engine fuel reservoir
• CPC Class Codes: F02D 41/0082 per groups or banks F02D41/0087 takes precedence
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/0245 by increasing temperature of the exhaust gas leaving the engine
• CPC Class Codes: F02P 5/1506 with particular means during starting
• 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:

starting the engine by injecting fuel and inducting air in both the first and second groups of cylinders;

after starting the engine and when temperature of the emission control device is above a temperature value;

discontinuing fuel injection into the first group of cylinders; and

operating the second group of cylinders to combust a rich air-fuel mixture.

2. The method recited in claim 1 wherein said rich air-fuel mixture is formed by inducted air and injected fuel, and said temperature value is a minimum temperature that can support a catalytic reaction between rich gasses and oxygen.

3. The method recited in claim 1 wherein said discontinuing fuel injection into the first group further comprises operating the first group of cylinders to induct air with substantially no injected fuel, where the method further comprises operating the second group of cylinders to combust a lean air-fuel mixture after said rich air-fuel mixture combustion when a desired catalyst temperature is reached.

4. The method recited in claim 1 wherein said starting the engine further comprises combusting said injected fuel and inducted air in both the first and second groups of cylinders.

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:

starting the engine from a non-rotating position by cranking the engine via an electronic device and injecting fuel and inducting air in both the first and second groups of cylinders;

indicating that engine speed is greater than a predetermined value; and

in response to at least said indication and when temperature of the emission control device is above a temperature value;

discontinuing fuel injection into the first group of cylinders; and

operating the second group of cylinders to combust a rich air-fuel mixture.

6. The method recited in claim 5 wherein said emission control device is a NOx trap, and where after the second group is operated rich, said second group is operated lean.

7. The method recited in claim 6 wherein said rich air-fuel mixture is formed at least from injected fuel and inducted air and said temperature value is a minimum temperature that can support a catalytic reaction between rich gasses and oxygen.