A New Diagnosis Method for an Air-Fuel Ratio Cylinder Imbalance Hitachi, Limited

Format:

Conference/Event

Author/Creator:

Nakagawa, Nakagawa, author.

Contributor:

Fukuchi, Eisaku

Numata, Akihito

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

A new diagnosis method for an air-fuel ratio cylinder imbalance has been developed. The developed diagnosis method is composed of two parts. The first part detects an occurrence of an air-fuel ratio cylinder imbalance by using a two revolution frequency component of an EGO sensor output signal or an UEGO sensor output signal upstream from a catalyst. The two revolution frequency component is from a cycle where an engine rotates twice. The second part of the diagnosis method detects an increase of emissions by using a low frequency component which is calculated from the output of an EGO sensor downstream from the catalyst. When the two revolution frequency component calculated using the upstream sensor output is larger than a certain level and the low frequency component calculated using the downstream sensor output is shifted to a leaner range, the diagnosis judges that the emissions increase is due to an air-fuel ratio cylinder imbalance. The experimental results using a test car showed that the diagnosis detected NOx emissions increasing by 1.5 times

Notes:

Vendor supplied data

Publisher Number:

2012-01-0718

Access Restriction:

Restricted for use by site license