A variety of continuously variable transmissions types are already 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, however. He's developed a CVT featuring no belts or pulleys, and all 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 speed regardless of vehicle speed. We've looked over the patent application and the typically dense language did 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 have a modulator mechanism that can rotate the shafts, thereby adjusting the effective input-to-output ratio. As near as we can tell, 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 sole 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's factored into the savings is presently unknown. Hopefully, we'll see more of this and learn precisely how it works.

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