yeah, I’m the dumbass.
I’ve been talking about this since 2007.
Turbines are efficient. They are most efficient when they run at a constant speed- not varying speeds like driving. You don’t need varying speed to charge batteries, you just need one RPM, and need it consistently. using the turbines at a consistent speed to charge a battery? To get a highly efficient 500 mile range out of a car that will go from 0 to 60 in under 3 seconds? And was capable of running on almost any fuel?
They aren’t using very efficient turbines, but they could be. They just picked some that are in the 20% efficiency range, but I’m confident it’s possible to combine a rankin/brayton cycle turbine to squeeze more like 50% efficiency.
NOW they’re talking. I should get one just on principle. Oh, and it’s a JAG with a body designed, if I remember correctly, by Louis Vuitton. Mr B should get one too, since we’ve been discussing the possibility of this very vehicle, though I don’t think he quite imagined an 800 hp firebreathing rocket.
As I understand it, the problem with turbines remains the same as it was for the Crysler turbine – the extreme temperatures at which turbines are most efficient.
Turbines are not dramatically hotter than early catalytic convertors- and even in the 60’s they had adquate materials to deal with those temps easily. No, the problem with turbines has always been they can’t deal with varying loads and varying torque demands easily, and varying their speed just causes them to lose efficiency.
I’ve been saying for years that diesel big rigs should be run using a small turbine combined with an electric drivetrain. I’m not an engineer, but it seems more efficient.
The thing about an electric drivetrain is the ability of electric controls to be incredibly efficient at accelerating and decelerating large loads or moderate loads at ludicrous speeds.
General Electric tried turbines as the prime mover on a turbine-electric railroad engine 50 years ago. It worked, but didn’t have the longevity or reliability required.
IIRC, airlines using turbines have to rebuild them at about the same time as piston engines, around 2500 hours. Garrett (Seattle?) builds all sorts of small turbines suitable for this service, in fact, they are IN this service as Auxiliary Power Units (APUs) all over the aviation world.
The other thing that works well is a small, de-rated diesel engine, and it will outlast the turbine by a factor of three or four times. The 50’s era Mercedes-Benz 190D engine, de-rated to around 20 hp, powers refrigeration units on thousands of reefer trucks nationwide.
There are a lot of answers out there, but to break barriers, it’s good to see the turbine people thinking outside the box.
A great many moons ago I was on a project involving small internal combustion reciprocating engines; the goal was how much horsepower could be obtained with reasonable (read: 10 minutes longer than the race) longevity.
We made some rather impressive gains and found that as HP increased – as expected – effective power band narrowed. What was surprising was the fuel efficiency gained, or, rather, not lost, as the engine operated in that “sweet spot” in the power band. If a constant velocity transmission could have been employed to maintain a constant RPM while applying maximum load, that would have been perfect; the engine could have operated at that one RPM where it was most efficient. The technology didn’t exist then to do that, and I’m not sure it’s sufficiently developed today to do it well.
Enter some of the solid state electrical controls we now have; couple a small turbo- or supercharged diesel to an alternator, have the diesel designed and tuned to operate at its most efficient RPM and manage the alternator load with controllers. A small battery pack to buffer for temporary demand conditions greater than the alternator capacity can supply, and feed power to motors at the drive wheels, eliminating transmission and drive train friction losses, and I think it might be a winner.
There must be something wrong with the idea, though, because I’m not aware of anyone who’s doing it outside of a very few simple industrial applications.