Seamlessly Shifting To Future!

A technology by Zeroshift that promises to make DSG seem slouch.

- Shashank Singh

Remember ERS, or energy recovery systems? What those are to an engine, seamless shifts are to a gearbox. The name implies the ability to change gears without allowing the driven wheel to feel any interruption in the flow of torque, something we accept as normal from conventional gearboxes.

As we said last issue, the automated manual transmission, or AMT, is popular because it combines all the great attributes of a manual gearbox with the convenience of an automatic. But AMTs also have the issue of jerking the vehicle’s passengers a bit in every gearchange. It comes from the momentary gap in acceleration as the automatic clutch breaks the flow of torque - zero acceleration - to make the gearchange.

Human beings adapt and we can learn to live with the headnods that come with the gearchanges. But we always try to do better, right?

The current best gearchange tech is Syncromesh - once the clutch is engaged, a dog ring (a ring with pegs, that’s splined on the gearbox input shaft) slides out to disengage from slots for those pegs (aka dogs) on the running gear’s cog. So the dog ring has to move on to the next dog on the next gear you’ve asked, and then the clutch is disengaged so that drive can resume.