Title:
METHOD FOR PURIFYING EXHAUST GAS OF AN INTERNAL COMBUSTION ENGINE
Document Type and Number:
WIPO Patent Application WO2002081887
Kind Code:
A3
Abstract:
The invention relates to a method for purifying exhaust gas of an internal combustion engine, which is operated under lambda control and which has an exhaust gas tract, in which a catalytic converter is located. A pre-catalytic converter lambda value of the exhaust gas is continuously detected upstream from the catalytic converter resulting in the generation of a pre-catalytic converter lambda signal, and this pre-catalytic converter lambda signal is used as a command variable of the lambda control. A post-catalytic converter lambda value of the exhaust gas is continuously detected downstream from the catalytic converter resulting in the generation of a post-catalytic converter lambda signal, which is dependent, in a monotonously decreasing manner, on the lambda value of the exhaust gas downstream from the catalytic converter. In a trim control, a correction of the lambda control is carried out using the post-catalytic converter lambda signal resulting in the generation of a measurement signal. Said measurement signal, at least less than a defined lambda value near lambda being equal to one, is dependent, in a strictly monotonously increasing or decreasing manner, on the lambda value of the exhaust gas downstream from the catalytic converter. In the event that signal levels of the post-catalytic converter lambda signal are greater than a threshold value, the additional measurement signal is used for trim control, and in the event that signal levels of the post-catalytic converter lambda signal are less than this threshold value, the post-catalytic converter lambda signal itself is used for trim control.
Inventors:
ROESEL GERD (DE)
ZHANG HONG (DE)
ZHANG HONG (DE)
Application Number:
PCT/DE2002/000839
Publication Date:
December 12, 2002
Filing Date:
March 08, 2002
Export Citation:
Assignee:
SIEMENS AG (DE)
ROESEL GERD (DE)
ZHANG HONG (DE)
ROESEL GERD (DE)
ZHANG HONG (DE)
International Classes:
F02D41/14; (IPC1-7): F02D41/14
Domestic Patent References:
| WO1994019593A1 | 1994-09-01 |
Foreign References:
| EP1143132A2 | 2001-10-10 | |||
| DE19819461A1 | 1999-11-04 | |||
| DE19852244C1 | 1999-12-30 |
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