Gas Turbine cars
Discussion
An odd one here, forgive me if its been asked before.
Now, I only have a rudimentary understanding of vehicle technology and the like. I'm no automotive engineer, but have a question- what with the constant drive for fuel economy and efficiency, why has the concept of gas turbine powered cars not been revived? From my understanding, even if you ignore the issues with battery life, electric cars are only as clean as the power source that charges them, and hybrids that use engine power rather than wasted energy from braking to generate power must be less efficient than just using the engine on its own (something to do with power losses from converting energy to electricity and storing it, then powering another motor with it.
Aren't modern gas turbines something like 80% efficient? That's a huge degree more than conventional petrol engines. To my understanding they're also less complicated than piston engines, and can be run on almost anything volatile (or can they?). They see widespread use in aircraft, helicopters, tanks, other military vehicles, naval applications and have even been used in bikes- so why not in cars?
Anyone with a greater knowledge able to shed some light on this? I know the ones that Chrysler built in the 50s had problems with fuel economy but aren't modern gas turbines much more economical than petrol engines?
Now, I only have a rudimentary understanding of vehicle technology and the like. I'm no automotive engineer, but have a question- what with the constant drive for fuel economy and efficiency, why has the concept of gas turbine powered cars not been revived? From my understanding, even if you ignore the issues with battery life, electric cars are only as clean as the power source that charges them, and hybrids that use engine power rather than wasted energy from braking to generate power must be less efficient than just using the engine on its own (something to do with power losses from converting energy to electricity and storing it, then powering another motor with it.
Aren't modern gas turbines something like 80% efficient? That's a huge degree more than conventional petrol engines. To my understanding they're also less complicated than piston engines, and can be run on almost anything volatile (or can they?). They see widespread use in aircraft, helicopters, tanks, other military vehicles, naval applications and have even been used in bikes- so why not in cars?
Anyone with a greater knowledge able to shed some light on this? I know the ones that Chrysler built in the 50s had problems with fuel economy but aren't modern gas turbines much more economical than petrol engines?
XitUp said:
Throttle response is your big problem.
Now, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
Some more background reading has indicated that they're very inefficient at low speeds but very efficient at high ones- so I can see where that is coming from. Wouldn't it be possible to gear it in such a way that its always above, say, 60% efficiency though?Now, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
XitUp said:
Throttle response is your big problem.
Now, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the Howmet TX overcame that problem with huge wastegates and pretty much 100% throttle 100% of the timeNow, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the main problem with gas turbines, is that the smaller they are, the thirstier they get for any given HP rating.
and the bigger they are... the more they cost. and finally... they work best up where the air is thin.
look on youtube though.. theres a Honda CRX thats had a Turbine fitted, and a red Porshe thing also.
CraigyMc said:
XitUp said:
I guess, like have a CVT and have the engine running at a constant speed.
Er, so, like run the turbine at full speed all the time?It would be operating at peak power all the time (coincident with peak efficiency). What would you do with all the surplus power?
C
Generate electricity to power a Sampson Radar
Move 6000 tonnes at 20 knots.
Oh wait, that's a Type 45 destroyer.
SystemParanoia said:
XitUp said:
Throttle response is your big problem.
Now, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the Howmet TX overcame that problem with huge wastegates and pretty much 100% throttle 100% of the timeNow, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the main problem with gas turbines, is that the smaller they are, the thirstier they get for any given HP rating.
and the bigger they are... the more they cost. and finally... they work best up where the air is thin.
look on youtube though.. theres a Honda CRX thats had a Turbine fitted, and a red Porshe thing also.
Marf said:
I love having a mooch about some of the GT clips, wonderful sound and some great DIY jobbies in amongst there.http://www.youtube.com/watch?v=dtUdhkJvjZo&fea...
Edited by Balmoral Green on Thursday 24th June 17:34
ManOpener said:
SystemParanoia said:
XitUp said:
Throttle response is your big problem.
Now, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the Howmet TX overcame that problem with huge wastegates and pretty much 100% throttle 100% of the timeNow, stick a little one in as a generator in an electric car and run it at peak efficiency and you're talking.
the main problem with gas turbines, is that the smaller they are, the thirstier they get for any given HP rating.
and the bigger they are... the more they cost. and finally... they work best up where the air is thin.
look on youtube though.. theres a Honda CRX thats had a Turbine fitted, and a red Porshe thing also.
unless the thin air was so the AIRCRAFT created less drag allowing the engine to be more efficiant that way ?
either way, i want a Howmet in my 10 car garage!
Nice article in Racecar engineering this month showing a turbo'd hillclimber that uses a small gas turbine as an anti-lag/zero-lag device. Basically it just provides gas flow when the engine would otherwise slow/stall the turbo wheels, the result is instant power and no lag across the entire rev range... it also means a much bigger turbo can be used so even more power and it all runs off regular petrol.
It'd be a spectacular achievement to get 60% mechanical efficiency out of an automotive sized unit, I suspect that figure comes from thermal recovery as well as mechanical output.
I've heard of 30% touted as excellent for a turbine, and it'd be less once you've geared it down and turned it into leccy.
You're right though it is quite an interesting idea, and one that is quite often considered round these parts.
Main advantages are power to size and weight, and the potential for futuristicy sound effects
Main drawbacks are (currently) efficiency, start up time, slow response, running speed (for power generation), cost and availability of small enough units
I've heard of 30% touted as excellent for a turbine, and it'd be less once you've geared it down and turned it into leccy.
You're right though it is quite an interesting idea, and one that is quite often considered round these parts.
Main advantages are power to size and weight, and the potential for futuristicy sound effects
Main drawbacks are (currently) efficiency, start up time, slow response, running speed (for power generation), cost and availability of small enough units
Gassing Station | General Gassing [Archive] | Top of Page | What's New | My Stuff