turbine efficiency

[bmwboarder]

I too would love to see this in a normal car. I applied for a grant once to try and build a turbine car (out of a VW bug), but didn't get the grant I've been intrigued ever since though, as turbines run smoother (less vibration), with less parts and weight, more fuel adaptability, and higher efficiency. Using it to fuel an electric car seems to be even better too as the turbine could just spin at super high efficiency! Maybe use 2-100hp electric motors in the rear with one 20-40hp turbine supplying it... that would be a lot less weight than the jaguars huge electric motors, and turbines. I hope some car manufacturers are wondering the same thing. Do you think its just cost that is prohibitive? Or maybe the heat is still an issue?

[user removed]

Originally Posted by bmwboarder

A couple more things I find cool is that a turbine can run at up to 60% efficiency, compared to 18-20% of our gas engines, when they aren't in idle... Also, turbines can take all sorts of fuels, including bio-fuels.

Do you have a link to that 60% figure.

regards
Mech

[gone-ot]

...and, at what ALTITUDE (air pressure)?

[user removed]

In power generation where the waste heat is used to create steam for a steam powered turbine 60% efficiency is reached.

A Pelton wheel exceeds 90% efficiency in hydro plants.

Gas turbines by themselves are maxing out at 35% and in most cases that is at high altitudes where ambient temperatures of 40 below and greater make cooling a non issue.

IC engines are approaching 60% now without power generation from exhaust heat.

The Chrysler turbine cars of the early 60s were good for about 12 MPG.

Turbines like diesel engines that approach the peak efficiencies listed are generally very large and not suitable for passenger cars.

They are also extraordinarily expensive to build, and micro turbine efficiencies are lower than small diesel engines like some of the VW produced passenger car engines that are in the neighborhood of 41% at best BSFC.

Combine the piston in cylinder of the typical IC engine, then eliminate the reciprocation penalties and you will see a small engine pass 60% efficiency. Just my opinion.

regards
Mech

[bmwboarder]

This page says up to 60% in a combined cycle (I think that means adding a secondary steam turbine?). It also says a standard one can produce 35-40% thermal efficiency. Though on other pages I find efficiencies stated anywhere from 15%-85%...

Gas turbine - Wikipedia, the free encyclopedia

This page says even over 60% is possible:
Turbine Efficiency

Also interesting:
Turbine Calculation

I guess the big question is, what kind of efficiency can they achieve in a microturbine that fits and works in a car?

[user removed]

25%.

Co-generation means they are using the exhaust heat from a gas turbine to generate steam for a steam turbine.

In the Titanic they used a combination of steam turbines and triple or quadruple expansion piston engines, because the piston engines were more efficient.

The first all big gun Battleship, Dreadnought (1906), had oil fired steam turbines. Not because they were more efficient, because they could obtain higher sustained speeds and the vibration from a 20 ton piston in a giant reciprocating steam engine was substantial.

regards
Mech

[user removed]

Thrust specific fuel consumption - Wikipedia, the free encyclopedia

Most gas turbine's efficiency is measured differently from engines that produce power through a shaft.

The huge Mann IC 2 strokes are listed at 54.4% in the Wiki article on BSFC.

The best gas turbine is a turbo fan. They produce huge amounts of thrust pressure, enough to move large rock weighing many hundreds to thousands of pounds that are positioned behind the turbine.

The compression ratio of most turbines is less than 7 to 1 which is one of the reasons they are not that efficient.

It would be difficult to get any patent on a turbine powered vehicle since that was done 60 years ago, possibly longer.

I Wonder what kind of fuel mileage Jay Leno gets in his turbine powered motorcycle. I'll bet it is not good.

regards
Mech

[bmwboarder]

That is interesting that you mention the Chrysler only getting 12mpg, because I thought I remember them getting 20mpg on one of the later models, which was decent gas mileage for back then. But of course I can't find that info anymore

If the jaguar can get 30mpg with its setup, it would sure seem like a smaller setup could get much higher gas mileage with much less weight and even a 1/4 of the power needs. Old M, do you think there is no chance they will come out in high mileage production cars?

[user removed]

Hypermilers here demonstrate the effectiveness of capacitive energy storage and efficiency minded operation of vehicles.

Engine operation only at peak efficiency.

The techniques can be automated specific to any single person.

The secret is to recapture inertia and provide for an infinite number of ratios of engine RPM to vehicle wheel RPM, in a vehicle that is simple and inexpensive.

My patent 7677208 is directed to that purpose. It also allows for a major simplification of the power train and highest efficiency in regeneration.

In the future I believe there will be two paths of development.

Battery technology for electric vehicles.

High efficiency engines and Infinitely Variable in wheel drives with capacitive energy storage.

When engines get to 60% conversion efficiency and power trains reach 93% in drive and 85% in regeneration, then the combination will make vehicles achieve over 100 MPG of liquid fuels and probably 2 to 3 times that amount on electricity.

The US should immediately start a new "Manhattan Project" to solve our energy requirements permanently.

300 billion in import trade deficits wiped out, would mean 3 trillion in new capital in this country every year.

I believe it is our only chance to continue the prosperity we have enjoyed over the last two centuries.

regards
Mech

[jamesqf]

Originally Posted by Old Mechanic

IC engines are approaching 60% now without power generation from exhaust heat.

I'd like to see evidence of that, especially in the sizes & duty cycles used in a car.

And I have to ask again, if they're so efficient, why aren't they used as the first stage of combined-cycle generation plants, etc?

The Chrysler turbine cars of the early 60s were good for about 12 MPG.

What were similar-sized IC-engined cars getting back then, though?

Also, you had the problem (same as with IC engines) of not being able to run at optimum efficiencies most of the time, 'cause you had to connect the turbine shaft to a transmission. With a setup like this Jaguar, you either run at optimum or not at all, which is a big win for average efficiency.