Progress in Automotive Transmission Technology

Much progress has been made in the development of automotive transmissions over the past 20 years, e.g., an increased speed number, expanded ratio spread and improved efficiency and shift quality. Automotive transmissions are moving toward electrification in response to stringent legislation on emissions and the pressing demand for better fuel economy. This paper reviews progress in automotive transmission technology. Assisted by computer-aided programs, new transmission schemes are constantly being developed. We therefore first introduce the synthesis of the transmission scheme and parameter optimization. We then discuss the progress in the transmission technology of a conventional internal combustion engine vehicle in terms of new layouts; improved efficiency; noise, vibration and harshness technology; and the shifting strategy and control technology. As the major development trend, transmission electrification is subsequently discussed; this discussion includes the configuration design, energy management strategy, hybrid mode shifting control, single-speed and multi-speed electric vehicle transmission and distributed electric drive. Finally, a summary and outlook are presented for conventional automotive transmissions, hybrid transmissions and electric vehicle transmissions.