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Title:
INTER-CYLINDER AIR/FUEL RATIO IMBALANCE JUDGMENTAL DEVICE FOR INTERNAL-COMBUSTION ENGINE
Document Type and Number:
WIPO Patent Application WO/2010/089887
Kind Code:
A1
Abstract:
An inter-cylinder air/fuel ratio imbalance judgmental device has an upstream-side air/fuel ratio sensor (67), a catalyzer (53) and a downstream-side air/fuel ratio sensor (68) that are provided at the downstream from an exhaust-collector part for an exhaust pathway, and calculates a sub-feedback quantity for matching an output value of the downstream-side air/fuel ratio sensor to a value corresponding to the theoretical air/fuel ratio, while performing an air/fuel ratio feedback control for matching an air/fuel ratio of the air-fuel mixture to be supplied to an internal-combustion engine to the theoretical air/fuel ratio in accordance with the sub-feedback quantity and an output value of the upstream-side air/fuel ratio sensor. At this time, the judgmental device acquires an imbalance judgmental parameter on the basis of a learning value for the sub-feedback quantity, judging that an inter-cylinder air/fuel ratio imbalance has occurred when the imbalance judgmental parameter exceeds a threshold. On the other hand, when the update frequency of a learning value for the evaporative fuel gas concentration after startup of the internal-combustion engine is less than a given frequency, the judgmental device prohibits a judgment for the inter-cylinder air/fuel ratio imbalance because the imbalance judgmental parameter is affected by purging of the evaporative fuel gas.

Inventors:
KIDOKORO TORU (JP)
SAWADA HIROSHI (JP)
IWAZAKI YASUSHI (JP)
NAKAMURA FUMIHIKO (JP)
Application Number:
PCT/JP2009/052123
Publication Date:
August 12, 2010
Filing Date:
February 03, 2009
Export Citation:
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Assignee:
TOYOTA MOTOR CO LTD (JP)
KIDOKORO TORU (JP)
SAWADA HIROSHI (JP)
IWAZAKI YASUSHI (JP)
NAKAMURA FUMIHIKO (JP)
International Classes:
F02D45/00; F02D41/14; F02M25/08; G01M15/05
Foreign References:
JP2007023917A2007-02-01
JP2004278542A2004-10-07
JPH06101545A1994-04-12
JPH08284713A1996-10-29
JP2008038785A2008-02-21
JP2000220489A2000-08-08
JPH01172473A1989-07-07
JP2000065782A2000-03-03
JP2004069547A2004-03-04
JP2007239700A2007-09-20
JP2003336535A2003-11-28
JP2004036475A2004-02-05
Other References:
See also references of EP 2395221A4
Attorney, Agent or Firm:
PROSPEC PATENT FIRM (JP)
Patent business corporation Pros Peck patent firm (JP)
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