GameboyRMH
GameboyRMH MegaDork
6/23/15 1:02 p.m.

Who could forget this solid dime of a concept?

The idea was for it to have a nearly 200hp electric motor for each wheel and power came from a battery and a pair of onboard mini-turbines. I think those turbines were chosen more for artistic reasons than anything else, they did have their inlets open to the cabin after all. A prototype was built that used a heavily modified and even more heavily boosted EcoBoost I4 instead and had one electric motor per axle.

But the original concept was actually just one very slight change from a brilliant and practical setup. Off-the-shelf batteries are still heavy and expensive. Turbines are light and used aircraft units that are no longer fit to fly on paper are...less expensive. And they're much lighter on fuel than an ICE under constant load conditions. I'm surprised nobody's tried an AWD electric supercar with a small battery pack and a used aircraft turbine or maybe an aircraft APU for power. It makes a lot of sense right now. the Koenigsegg Regera has come close, I wouldn't be surprised if the next top-of-the-line Koenigsegg uses this setup.

Keith Tanner
Keith Tanner MegaDork
6/23/15 1:15 p.m.

I loved the idea of that concept with the microturbines. It does make a lot of sense. Maybe pair them with a supercap for rapid extraction of energy.

GameboyRMH
GameboyRMH MegaDork
6/23/15 1:39 p.m.

Supercaps and EVs are like chocolate and peanut butter! One just for compensating for turbine lag (in both directions) would be a great idea.

Keith Tanner
Keith Tanner MegaDork
6/23/15 2:54 p.m.

How are we not obsessed with the fact that Le Mans cars now have four digit horsepower levels thanks to their hybrid systems? I think it was Toyota that was basically planning to have so much power on tap that they'd be impossible to pass, and they were bragging about the energy recovery speed of the supercaps.

nderwater
nderwater PowerDork
6/23/15 3:16 p.m.

Because nearly all of us hear 'hybrids' and think...

Rusted_Busted_Spit
Rusted_Busted_Spit UberDork
6/23/15 3:18 p.m.

The Le Mans P1 cars are amazing no two ways about it.

GameboyRMH
GameboyRMH MegaDork
5/11/16 3:19 p.m.

Thread resurrection: This kind of powertrain is now being tried in a series-hybrid semi truck:

http://www.engadget.com/2016/05/11/nikola-motor-company-tesla-of-trucking/

GameboyRMH
GameboyRMH MegaDork
8/24/17 9:44 a.m.

Thread resurrection 2: Ariel says they're going to put a supercar into production with a powertrain just like the CX-75 concept's, complete with turbine. Also it could pass for a Batmobile:

http://www.speedhunters.com/2017/08/ariel-enters-the-hipercar-game/

From what little is visible in the pics, it looks like a very small aircraft APU.

rslifkin
rslifkin SuperDork
8/24/17 9:50 a.m.

Turbines are often less efficient than piston engines, which can be a problem. And then there are a few issues that the hybrid setup helps to mitigate: turbines don't respond to power changes quite as fast and they generally lose efficiency when you move away from full speed / full power.

GameboyRMH
GameboyRMH MegaDork
8/24/17 9:55 a.m.
rslifkin wrote: Turbines are often less efficient than piston engines, which can be a problem.

For mechanically driving a car, certainly, but under steady load they're easily 2-3x as efficient as a piston engine. The hybrid system takes care of that, the turbine only has to run either flat out for charging or not at all.

rslifkin
rslifkin SuperDork
8/24/17 10:03 a.m.
GameboyRMH wrote: under steady load they're easily 2-3x as efficient as a piston engine.

I'm pretty sure that's not the case in the size range we're talking about here. Turbines are smaller / lighter relative to their power output, but not more efficient. Both types of engines get more efficient as they get larger, but at the same size, a turbine typically burns more fuel.

Looking at some examples I found online, a modern small BMW turbodiesel (130kw output) has a BSFC of around .326 lb/hp-hr. A 1300kw (already much bigger) General Electric CT7 turboprop is up around .413 lb/hp-hr. Going bigger on the turbine improves efficiency, but only the most massive (as in hundreds of MW output) turbines do better than the diesel recip engines.

Mind you, a turbine doing better than a gas recip engine is pretty easy to achieve.

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