Gas turbine/electric hybrid?

Lack of fuel economy and pick-up was the principle operational deficiency
of pure turbine power. Might not this be solved by using a gas turbine
intermittently to charge a battery which then drives an electric propulsion
motor?

Electric motors develop maximum torque at zero rpm, making for snappy
pickup and eliminating the need for a complex transmission. A battery
stores energy for the motor, with the energy being replaced by a gas
turbine. The turbine need not run much around town for short trips until
the battery runs low on chemical energy and needs recharging. On the open
road, the car is powered principally by the turbine, but since it runs at
its efficient speed, it need not have a large fuel burn in terms of pounds
of fuel per horsepower hour, which the bottom line should yield
efficiencies no worse than a piston engine.

An automotive gas turbine, with waste heat regeneration, used at a constant
speed would be quite efficient. Sizewise, the rotor probably need not be
larger than a kitchen toaster for 80 hp out. Gas turbines also will run on
a wide variety of gaseous and liquid fuels, helping to aleviate the high
cost oil supply situtation. You could run a gas turbine on hydrogen
electrolized from water using wind turbines for a fossil fuel-free
transportation system. Alternatively, you could run a gas turbine on
natural gas, LPG, kerosine, even liquid coal or any other clean burning
fuel.

As for the high cost of gas turbine engine development and construction,
there are solutions. The development should be by a consortium of
cooperating companies, who will do the research and development and the
government which will finance the project. It will take many billions of
dollars. The government can invest these many billions and later reap
licensing returns during production. Patent protection and enforcement
will allow only those government-licensed companies to produce the patented
power plants. Standardization will keep down the costs. Only one engine
design, in three sizes need be developed: small, medium and large (80, 160
and 320 hp) for various sized passenger vehicles and small trucks.

Manufacturers can distinguish their products by differentiation of their
chassis and body. For instance, Ford can go for round taillamps, GM can
mount tail fins, and Chrysler can put racing stripes down the sides. The
engines will all be the same, Thankfully for the mechanics who now struggle
to service the myriad of makes and models which are all different, but all
do the same simple end function: to power two tons of automobile down the
road.

Costs can also be reduced by recycling the rotors, the most expensive part.
When a car is junked, the rotor can go into a new car. This can be made
legal by statute law. A used rotor will be as good as new one after
inspection and refurbishing. The secret is in the HEPA air cleaner which
will prevents all erosion of the rotor blades due to particular matter
impaction. With a rotor lasting 25 to 50 years, the previously high cost
of gas turbines will be just a footnote in the history of technology.

A diesel hybrid might work just as well and certainly should be considered,
but it doesn't have the desired high-tech sound of a 50,000 rpm whine.

 

Nomen Nescio wrote:

"Electric motors develop maximum torque at zero rpm......."

Is that so?
Unfortunately Nomen, you are a poser, just cutting and pasting things
you read. That leaves you making error after error in how things are or
could be.

 

Depends on the type of motor used.

Actually turbine-electric makes some sense: turbines are efficient at
constant speed and offer both high efficiency and light weight,
offsetting the heavy batteries. Regeneration is unnecessary in a
constant--power setup: the turbine expanders can be optimized for that
regime.

Emissions would be a deal killer because it would take intense and
long development to get them to recip standards. The best thing that
could be done for turbine car buffs would be to enact a emissions
_certificatiion_ waiver for turbine cars for a set time, so as to make
it worthwhile for some company to build a fair run of them. The waiver
should be carefully written to force the outright sale, not lease or
test loan, of the cars so they cannot destroy them like the Chrysler TC
program or the GM and Ford factory electrics.

 

If you want to look at economical hybrids, look to a diesel-electric
combination like locomotives use. In a vehicle hybrid of this sort the
electric motors would always be the prime movers and the diesel would use an
auto-throttle and auto-switch to either send the electricty directly to the
motors or into storage batteries. You accelerator pedal would regulate the
juice going to the electric motors only and not the RPM of the charging
diesel. Since diesels are more efficient at idle than a gasoline motor of
the same size/output, you can use the power in the batteries to do all the
accelerating and stop-and-go driving (keeping the diesel at idle RPM for a
much longer time than using a directly coupled motor) and only have the
diesel increase RPM when you need either the batteries charged or a direct
flow to the electric motors for power. In addition, a hybrid of this type
would not need any significant leaps of technology or waivers for emissions.

Just my two cents worth - Jonathan

 

Gas turbine engines are very expensive to build. I doubt that we will
ever see significant application to automobiles. It has been tried,
many times, and came up short.

John

 

It would make _more_ economic sense, but it still wouldn't make
economic sense, not at US fuel prices. A few people would pay a lot of
money for the novelty of a turbine car, diesels are not novel.
Straight diesel cars, which do make economic sense, are unobtanium in
the US, because of consumer apathy and emissions laws combined with a
refusal to require Euro-spec fuel for the current generatioon of CRD
engines.

 

Well Mr. Bundy, I am afraid that Nomen is correct, at least for
permanent magnet electric motors. Have a look at:

http://claymore.engineer.gvsu.edu/~jackh/books/model/html/model-71.html#54931

John

 

And the V12 in the Lambo is a low build cost powerplant?? No, gas
turbines are not necessarily incredibly expensive to build. My guess is
the Allison 250 costs less to build than a Lyc or Continental recip of
half the power: the P&W PT-6 is probably twenty or thirty thousand
dollars of actual labor, materials, and other hard build cost.

There are probably five hundred people who would buy a turbine exotic
car in the $200-300K price class in the US any given year, enough to
make it doable. The "Bugatti" Veyron is well into seven figures, at
which point buying a off the shelf ST6 at market price from P&WC
becomes a legit option economically speaking. However, it would make
for a miserable road car, but the Veyron probably is that to begin
with, to say nothing of the modified Stingray the Granatellis foisted
off on some dumb yuppie idiot for a six-figure price with a junk runout
training PT6 they mooched off P&W a decade earlier many years ago.

 

There are better options under development... one being the CAM-Vane engine
which developes a lot of power in a little space, runs on diesel without
sounding like one and is pretty light weight for power produced, thus is
economical...{being developed for unmanned drone aircraft} no word on the
pollution aspects, but I'd guess they're no worse that a wankel.

 

Anything developed for, or primarily intended for sale to the DOD is
going to be so overpriced due to contractor spoilage as to not be worth
considering.

 

Well John, you are wrong because you took a blanket statement and
qualified it to suit your answer. Again, nice pasting job though.

 

There are a LOT of varibles in electric motor design that can effect at
what RPM peak effort is achieved. Generally though with traction type
motors used to power electric cars and such, they achive maximum torque
at zero or very low RPMs to get the load moving.

 

Yeah.... like all that technology developed under NASA/ Space funding..
total waste of money, considering we never saw any of it!

Good Catch!

 

NASA developed many new technologies that have passed on to the public.

Do a Google search, you will be impressed.

Progress is never a waste of money.

 

Yeah.... like all that technology developed under NASA/ Space funding..

What about velcro ? High impact plastic ? Fuel Cells ? GPS ?
Satellite TV and Radio ?

Lynn

 

Heh.. gee... never THOUGHT of that!!1



There's more, btw.

 

Actually the DOD was behind the GPS program at the start. NASA provided
the taxi for it.

 

More importantly what about the need to make things small that let to
better computers, cell phones, and microscopic surgery such as eye surgery,
organ surgery and transplants. As well as the ability to reattach severed
limbs etc?

mike hunt

 

Most of the things you mention had a tangential relationship to the
space program. It's true the space program speeded up many of those
things, but not that we would not have any of it without them. And
perhaps the pace of progress would have limited some of the regress we
have to face too, like offshoring of jobs, elimination of repair jobs,
and cheapening of all manner of products. It goes both ways.

Once a company has derived most of its income from NASA or the Air
Force it is permanently spoiled and will never want to work again for a
living. You'd have to fire or kill all of the executives and most of
the management to get them to pursue gainful market endeavors at
reasonable per-piece profit levels.

 

The Space Program's necessity of the materials, mapping, weather forcasting,
etc. promted their development and the speed of their developement. The
things mentioned may not be here today if it had not been for the Space
Program. True, your point of jobs, it does go both ways, but , a basic
economics class dictates if one has the money and needs labor, and one has a
labor pool, but needs the money, a relationship will develope that will
benefit both. Nothing new, been going on for thousands of years.

As long as the contractor is delivering their products within the
contractual requirements of NASA and the Air Force, they are within a
gainfull market.