There are already a variety of types of continuously variable transmissions on the market, including the well-known variable pulley and belt type used by companies like Honda, Suzuki and Subaru. Australian Steve Durnin thinks he has a better idea. The CVT he has developed has no belts or pulleys and all of the gears are continuously engaged.

A short video on Australian TV doesn't really offer much insight into the workings of the device but, like others, it is intended to keep an engine operating at its most efficient level regardless of vehicle speed. We've looked over the patent application and the typically dense language only did a little bit to enlighten us. Nonetheless, we'll try to explain what we think might be happening.

The system consists of a pair of ring gears and parallel transmission shafts. Each of the shafts has a modulator mechanism that can rotate the shafts, thereby adjusting the effective input to output ratio. As near as we can figure out, it uses something similar to a mechanism that makes a differential work to adjust the relative rotational speeds of the two shafts. It's difficult to tell from the one illustration just how everything moves around. Durnin claims the transmission can provide a 20 percent improvement in efficiency. However, the modulator mechanism will require some energy input to work. Whether that is factored into the savings is not known right now. Hopefully, we will see more of this and learn precisely how it works.

[Source: Bayside Bulletin, WIPO, Australian Broadcasting Corp.]

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