Overall scheduling of a lean burn engine system

• US 6,925,982 B2
• Filed: 06/04/2002
• Issued: 08/09/2005
• 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, Roth, John M.
• Primary Examiner(s): MOHANTY, BIBHU R
• Application Number:
  US10/064,006
• Publication Number:
  US 20030221659A1
• Time in Patent Office: 1,162 Days
• Field of Search: 123/294, 123/295, 123/305, 123/299, 123/434, 123/198.F
• US Class Current: 123/295
• 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 2430/02 by cutting out a part of engine cylinders
• 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 2570/14 Nitrogen oxides
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 9/005 using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
• CPC Class Codes: F02D 2200/0404 Throttle position
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/0802 Temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0082 per groups or banks F02D41/0087 takes precedence
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1453 the characteristics being a CO content or concentration
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/1463 : of the exhaust gases downstream of exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/187 : using a hot wire flow sensor
• CPC Class Codes: F02D 41/2461 : by learning a value and then controlling another value
• 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 system comprising:

an engine having a first and second bank, and a first group of cylinders and a second group of cylinders, with said first group having at least one cylinder from the first bank and one cylinder from the second bank, and said second group having a least one cylinder from the first bank and one cylinder from the second bank;

an exhaust manifold coupled to said first and second group of cylinders;

an emission control device coupled to said exhaust manifold, said device storing oxidants during lean operation and reacting said stored oxidants during stoichiometric or rich operation;

a controller that operates the engine in a first mode where the first group of cylinders operates with substantially no injected fuel and the second group operates combusting a air-fuel mixture, and during said first mode, periodically operates both the first and second groups to combust a stoichiometric or rich air-fuel ratio.

2. The system recited in claim 1 wherein during said first mode, said second group combusts a lean air-fuel mixture.