#range-extender

The Wankel rotary engine returns to its native land at last. Since the NSU Ro 80 went out of production in 1977, Mazda has been the keeper of the flame. But Audi has announced that it will show an A1 e-tron concept at the Geneva show this week, and the pug-in will feature a single-rotor Wankel range extender (gen set). Rotaries and micro-turbines have often been suggested as the ultimate range extenders due to their compact size and low weight.

As we saw in the last VBW, the Volt’s range-extender still needs some software work. But efforts to to keep the gas engine from acting like a thrashing, disembodied dervish will have to balance the desire for smooth operation and maximum efficiency. And it’s looking like efficiency in charge sustaining (CS) mode won’t match the hybrid standard-setters. Volt chief powertrain engineer Alex Cattelan breaks the news gently to the true believers at GM-volt.com

You’ve got to understand that all of the decisions that we’ve made around this product are made because its an EV. That is the first and foremost thing that it needs to be. So because it is an EV some of the decisions that we’ve made around engine operation will be different than what Toyota makes in its parallel hybrid. For them they are always operating in hybrid mode so they need to optimize everything for engine operation.

In our case we’re optimizing everything for EV operation and the secondary is certainly going to be better than conventional vehicles, but were not necessarily totally optimizing the system for charge sustaining mode because we don’t want to compromise electric vehicle mode.