Method and system of adaptive learning for engine exhaust gas sensors

• US 6,874,490 B2
• Filed: 03/24/2004
• Issued: 04/05/2005
• 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): SOLIS, ERICK R
• Application Number:
  US10/809,774
• Publication Number:
  US 20040182374A1
• Time in Patent Office: 377 Days
• Field of Search: 123/443, 123/295, 123/674, 123/198.DB, 701/109
• US Class Current: 123/674
• CPC Class Codes: F01N 2560/025 for measuring or detecting O2, e.g. lambda sensors
• 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 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/0032 Controlling the purging of the canister as a function of the engine operating conditions
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• 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 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/187 using a hot wire flow sensor
• CPC Class Codes: F02D 41/2441 characterised by the learning conditions
• CPC Class Codes: F02D 41/2448 Prohibition of learning
• CPC Class Codes: F02D 41/2454 Learning of the air-fuel ratio control
• CPC Class Codes: F02D 41/2474 Characteristics of sensors
• CPC Class Codes: F02D 41/3029 further comprising a homogeneous charge spark-ignited mode

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 group of cylinders;

a sensor coupled to at least one of said first and second groups; and

a controller for operating the engine in a first mode with a mixture of air and substantially no injected fuel in the first combustion group and with air and injected fuel in the second combustion group, operating in second mode where both of said first and second groups combusts a mixture of air and injected fuel, and disabling adaptive learning of the sensor during said first mode, enabling said adaptive learning during the second mode and determining degradation of the sensor.

2. The system recited in claim 1 wherein said adaptive learning comprises calculating a correction value for said sensor;

and when in said first mode, the second combustion group operates with a lean air-fuel ratio.

3. The system recited in claim 2 wherein said sensor is an exhaust gas oxygen sensor.

4. The system recited in claim 3 wherein said first and second cylinder groups have an equal number of cylinders.

5. A method for operating an engine having a first and second group of cylinders, comprising:

operating in a first mode with the first cylinder group operating with air and substantially no injected fuel and the second cylinder group operating by combusting air and fuel, providing a request for enabling adaptive learning of a sensor coupled to the engine;

in response to said request, disabling said first mode of operation and operating the engine in a second mode of operation; and

determining degradation of the sensor based on an operating condition.

6. The method recited in claim 5, wherein said second mode of operation comprises operating both first and second cylinder groups with a combusted air-fuel mixture.

7. The method recited in claim 6 wherein said combusted air-fuel mixture of said second mode is substantially near stoichiometry.

8. The method recited in claim 5 wherein said sensor is coupled to an engine exhaust.

9. The method recited in claim 5 wherein said sensor is an exhaust air-fuel ratio sensor.

10. The method recited in claim 5 wherein said adaptive learning corrects for sensor errors.