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An evaluation of Transient System Optimization used for spark calibration over the FTP urban schedule

Book ·
OSTI ID:5822573
Transient System Optimization (T.S.O.) was developed as a systematic means to optimize the calibrations of up to three engine control variables -- air-fuel ratio, spark advance and exhaust gas recirculation, to provide the minimum fuel penalty while meeting specified levels of exhaust emissions: HC, CO and NO/sub x/. In this study we evaluated the performance of T.S.O. in optimizing the spark advance calibration on the hot FTP urban schedule. The process was applied to each of the following cases: a mature spark calibration supplied with the vehicle, that calibration retarded by 10 degrees and an MBT calibration. This provided different initial conditions under which to evaluate T.S.O. The results of the study showed that the final calibrations achieved the same fuel economy as the mature calibration with equivalent or lower emisisons: however, the resulting spark advance calibrations were markedly different from each other. The authors have concluded that no unique optimum spark advance calibration exists because tradeoffs among spark table cells permit equivalent fuel economy and emissions for different calibrations.
OSTI ID:
5822573
Report Number(s):
SAE-TP-840850
Country of Publication:
United States
Language:
English