The optimization of a high performance engine in order to achieve maximum power at full load and high speed can cause an unstable behavior when the engine is running at different conditions, thus making a robust combustion diagnosis for on board diagnostic EOBD/OBD II purposes (misfiring detection) particularly challenging. In fact, when a misfire occurs, its detection can be critical because of the high background noise due to high indicated mean effective pressure (IMEP) cyclic variability.A partial reduction of the high IMEP variability had been achieved by optimizing control parameters of a new prototype high performance V8/4.2 l engine. Spark advance and VVT phasing maps had in fact been re-designed based on in-cylinder pressure variability (cycle by cycle and cylinder by cylinder) analysis.In this paper the focus is the analysis of innovative misfire diagnosis techniques (such as joint time-frequency analysis of the engine speed signal) to make the new prototype V8 engine compliant with EOBD/OBD II regulations.The instantaneous engine speed signal has been recorded during experimental tests while inducing various misfire patterns. Both test rig investigations (i.e., off-line data processing) and real time analysis for OBD purposes have been carried out.The basic misfire detection algorithm has been modified by introducing a pre-processing of the experimental data, allowing to improve the effectiveness of the misfire detection also at higher engine speed operating conditions.
An Approach for Misfire Diagnosis in Critical Zones of the Operating Range of a High Performance Engine
Sae Technical Papers
SAE 2003 World Congress & Exhibition ; 2003
2003-03-03
Aufsatz (Konferenz)
Englisch
British Library Conference Proceedings | 2003
|Statistical engine misfire detection
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