Theoretical and experimental analyses of torsional vibrations and acoustic noise for a deep hybrid electric vehicle driveline including an electric, continuously variable transmission are carried out. The dynamic and mathematical models with 16 degrees of freedom in a matrix form are developed for the torsional vibration characteristics of the hybrid driveline. On the other hand, the noise sources of the hybrid electric vehicle powertrain excited in the pure electric mode and the hybrid drive mode are tested and measured using acoustic and speed sensors. The noise orders and the frequency domain responses are constructed using signal treatment and torsional vibration analysis. The theoretical predictions for the natural frequencies and the corresponding vibration modes of the hybrid driveline are presented. The noise test results are also given in accordance with the torsional vibration modes of the hybrid driveline in the pure electric mode and the hybrid drive mode. The noise sources due to the self-excited and frequency-multiplied vibrations are found, focusing on the compound planetary gear set in the power-split electric, continuously variable transmission.

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A direct current of 5 A was applied to narrow strips of iron foil in air to synthesize iron oxide nanowires (NWs) via thermal oxidation route of resistive heating. Transverse electric fields of 0–4000 V/m were applied perpendicularly to the surface of the iron foil during thermal oxidations. Results showed that the Fe2O3 NW array can grow perpendicularly on that surface by using this kind of thermal oxidation method. Transverse electric fields applied during thermal oxidation significantly affected the morphology of the Fe2O3 NW array. With increasing strength of the transverse electric fields, the Fe2O3 NWs became much longer, thinner and denser in distribution, and the diameters became more uniform. Furthermore, solid state based-up diffusion growth mechanism for the Fe2O3 NW array was confirmed by thermal oxidation.

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