On Cyclic Variability in a Residual Effected HCCI Engine with Direct Gasoline Injection during Negative Valve Overlap

Figure 14

Wavelet power spectra of the net IMEP. The contour levels are chosen such that 75%, 50%, 25%, and 5% of the wavelet power are above each level, respectively. The cross-hatched region represents the cone of influence, where zero padding has reduced the variance.

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