Engine system and method for efficient emission control device purging

• US 7,481,039 B2
• Filed: 03/13/2006
• Issued: 01/27/2009
• Est. Priority Date: 03/05/2004
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Surnilla, Gopichandra, Smith, Stephen B., Goralski, Christian T. Jr.
• Primary Examiner(s): NGUYEN, TU MINH
• Application Number:
  US11/374,712
• Publication Number:
  US 20060162320A1
• Time in Patent Office: 1,051 Days
• Field of Search: 602/74, 602/76, 602/85, 602/86, 602/97, 603/01, 123/198.F, 123/295, 123/305, 123/443, 123/481, 123/493, 123/691, 123/692
• US Class Current: 60/274
• CPC Class Codes: F01N 2430/02 by cutting out a part of engine cylinders
• CPC Class Codes: F01N 2900/1614 NOx amount trapped in catalyst
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 9/00 Electrical control of exhaust gas treating apparatus monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• 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 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/1408 Dithering techniques
• CPC Class Codes: F02M 26/43 in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.

Claims

1. A method for controlling an engine having at least a first and second group of cylinders, comprising:

operating the engine in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates to combust air and injected fuel;

during a first condition, transitioning the engine to operating in a second mode wherein both the first cylinder group and the second cylinder group operate to combust air and injected fuel, combustion in both said first and second cylinder group being lean of stoichiometry at a lean combustion limit with retarded ignition timing; and

during a second condition, transitioning the engine to operating in a third mode wherein both the first cylinder group and the second cylinder group operate to combust air and injected fuel, combustion in both said first and second cylinder group being lean of stoichiometry less lean than the lean combustion limit without retarded ignition timing.

2. The method recited in claim 1 wherein said first condition and said second condition depend on engine airflow.

3. A method for controlling an engine having at least a first and second group of cylinders, each group comprising a plurality of cylinders, comprising:

operating the engine in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates to combust air and injected fuel;

during a first condition, transitioning the engine to operating in a second mode wherein both the first cylinder group and the second cylinder group operate to combust air and injected fuel, combustion in both said first and second cylinder group being lean of stoichiometry at a lean combustion limit with retarded ignition timing, wherein after said transition, airflow is decreased by closing a throttle valve of the engine; and

during a second condition, transitioning the engine to operating in a third mode wherein both the first cylinder group and the second cylinder group operate to combust air and injected fuel, combustion in both said first and second cylinder group being lean of stoichiometry less lean than the lean combustion limit without retarded ignition timing, wherein said first condition and said second condition depend on engine airflow.

4. The method recited in claim 3 wherein during said first condition, ignition timing is advanced while said airflow is decreased.

5. The method recited in claim 4 wherein during said first condition, fuel charge per cylinder is decreased while said airflow is decreased to maintain operation at said lean combustion limit.