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)
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:
Assignee:
TOYOTA MOTOR CO LTD (JP)
KIDOKORO TORU (JP)
SAWADA HIROSHI (JP)
IWAZAKI YASUSHI (JP)
NAKAMURA FUMIHIKO (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:
JP2007023917A | 2007-02-01 | |||
JP2004278542A | 2004-10-07 | |||
JPH06101545A | 1994-04-12 | |||
JPH08284713A | 1996-10-29 | |||
JP2008038785A | 2008-02-21 | |||
JP2000220489A | 2000-08-08 | |||
JPH01172473A | 1989-07-07 | |||
JP2000065782A | 2000-03-03 | |||
JP2004069547A | 2004-03-04 | |||
JP2007239700A | 2007-09-20 | |||
JP2003336535A | 2003-11-28 | |||
JP2004036475A | 2004-02-05 |
Other References:
See also references of EP 2395221A4
Attorney, Agent or Firm:
PROSPEC PATENT FIRM (JP)
Patent business corporation Pros Peck patent firm (JP)
Patent business corporation Pros Peck patent firm (JP)
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