GM’s decision to use its off-the-shelf 1.4 L four as the range-extender power source was a compromise born of necessity. The originally conceived 1.0 L turbocharged three cylinder engine didn’t exist (in the US), and GM’s pre-bankruptcy budget was a little constrained to spend the bucks for the tooling. The 1.4, in a different state of tune, is shared with the Cruze, as is as much of the rest of the car as possible. GM has made it pretty clear that the gen1 Volt is a bundle of compromises, given the time, technology and budget constraints it faced. But the gen2 is apparently another story. In an echo of GM past, Volt Vehicle Director Tony Posowatz tells Automotive Engineering that the engine options are wide open; way way wide open:
“That may be a Stirling cycle engine, perhaps it’s a Wankel, a gas turbine, a small displacement motorcycle engine– you can extend the possibilities to a lot of different alternatives.”
Aw come on Tony, this isn’t Popular Science of the sixties anymore. Unless the gen2 Volt is a lot longer off than the usual model cycle, isn’t it a bit late to be dusting off the Stirling cycle programs from back then? Or is this just the same old GM routine of seeding mid-engine Corvette rumors for the last five decades? I’m betting on the Wankel, because the tooling for GM’s Wankel engine is probably still in a warehouse somewhere.