Monday, October 25, 2010

The "Volt-gate" that Wasn't (or at Least Souldn't Be)

I've been following with some excitement the launch of the Chevy Volt and have been reading eagerly any and all "first drive" type reports.

Unfortunately, the automotive media, much like all the rest, seems intent in finding controversy in everything.

Apparently at some point during the initial Volt media campaign, it was "promised" that there would be no mechanical linkage between the gasoline 'range extender' engine and the wheels. All well and good, it seems. GM wanted to stress the difference between the Volt "series hybrid" model and the "parallel hybrid" model employed by the Toyota and Honda (and licensees thereof) systems. However, it turns out that there is a mechanical link between the IC Engine and the wheels, under certain circumstances, mostly 'highway cruising' and taken this "betrayl" as some kind of sign that GM is "back to its old self" post Federal Government bailout.

Below are my thoughts on the matter, initially posted as a response to a post at Motor Trend:
"I honestly don't understand why there's a "gate" here. Sure, it was silly of GM to so categorically state something, likely before the powertrain architecture was fully determined, but so what? I, as a mechanical engineer, can appreciate two key aspects of this situation:
1. I actually think the solution is pretty clever. It takes the "ICE-electric" hybrid model to the most reasonable compromise of the two prime movers involved. Electric motors are good at low speeds and or when you want a lot of torque, and ICE's like cruising at relatively high revs. That and using a planetary (epicyclic) gearset to effectively throttle power delivery between two prime movers and two sinks (either the mechanical power to the road or through the generator into the battery) is just plain cool."

2. GM "going back on its word" simply shows that they were willing to accept an engineering reality (that providing for a direct mechanical coupling between the ICE and the wheels) as the best way to provide the performance they were advertising (IE >100MPG), rather than simply plowing ahead with whatever solution they had in mind when they started up the publicity campaign.

I, for one, applaud all of GM's efforts and the engineering work they've done on the Volt. As far as I'm concerned, they're what hybrids should have been all along."

The point is, it seems to work pretty well: I've seen a few journalist reports of over 100 mpge (MPG-equivalent or MPG-electric, I'm not positive)), which is pretty remarkable, all things considered.

I'd definitely take one over an all-electric car or even any of the existing hybrids.