Half a croissant, on a plate, with a sign in front of it saying '50c'
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Microturbine Car

compact hybrid car runs on miroturbines
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Basically it is a compact hybrid car (size of a Honda Fit/ Toyota Yaris). Front wheel drive, lightweight,(possibly made of mostly composite and/ or aluminum). In the engine bay there is a power unit containing microturbines. From what I hear even small turbines are not that efficient, but microturbines are- (I am no expert, so I would need input from someone who knows about them). The car uses a lithium Ion battery pack and regenerative braking. The car runs off an electric motor only, the turbines transmit no physical energy to the wheels, only charge the battery. When you first start driving the car runs off batteries until turbines start up and make power. The entire unit is computer controlled and the computer determines how many of the turbines run given the battery pack power and driving conditions. The turbine exhaust run through a typical automotive catalyst system as to keep emissions legal. The turbines will start up or keep running after you park and exit the vehicle in order to maintain a certain battery charge (a proper emissions system should make this ok even if it runs inside an enclosed structure). Might be most efficient in urban driving scenarios. It might possibly be more efficient than a hybrid car using a traditional piston-driven (recriprocating) engine.
KineticKill, Mar 16 2008

Gas turbine car http://en.wikipedia...General_Motors_EV-1
[marklar, Mar 16 2008]

Gas turbine bus http://en.wikipedia.org/wiki/Designline
There are also trains, boats, tanks and bikes but there's no point linking them all. [marklar, Mar 16 2008]

microturbine car http://jalopnik.com...c-hybrid-255528.php
Micro-Turbine Electric Hybrid [KineticKill, Mar 16 2008]


       All sorts of turbine vehicles have been thought of. What's a microturbine, and where did you hear that it's all that efficient?
baconbrain, Mar 16 2008

       Yeah, I just checked "the Internet" for microturbines. They are just non-huge turbines, not qualitatively different from any other turbine.   

       Anybody who makes a microturbine is going to think of putting it in a hybrid car. He may change his mind, but he's going to think of it. This idea points out the obvious, without adding any information, and includes some error. [-]
baconbrain, Mar 16 2008

       Microturbines are not particularly more efficient than other turbines - but they can carry efficiency down to the point where they are competing with, say, batteries. Even then, they might not win on pure efficiency; but they can pack a much higher energy density than a battery.   

       I was a bit surprised to learn that "microturbine" includes things up to 250kw. But the really high efficiencies you sometimes see (like "80% or more") are from situations where there is co-generation from the waste heat, and then direct use of waste heat for heating a building.
lurch, Mar 16 2008

       Many "turbine" powered cars are on a large scale- buses, trains, boats, etc. I want to bring that technology down to a small scale that is really efficient. The point is to have a hybrid that can run on readily available fuel which can get the most out of the fuel that it burns. A lightweight car with a power plant that can vary its power output by using multiple, small turbines is what makes this car different. Similar, but not the same as other ideas posted.
KineticKill, Mar 16 2008

       So your idea is a "multi-turbine" hybrid car. Microturbines are used because they are small, which is needed if there's going to be more than one of them.   

       Well, that's kind of new. I guess. Multi-engine cars have been done, but not very well. So it's still not good. For several reasons.   

       Turbines, generally speaking, work better the bigger they are. One big turbine is more efficient than two little ones. Two are used for redundancy and for space constraints, but seldom does anyone put in two when one will suffice. As someone once told me, "Two engines are more than twice as much trouble as one engine." They are also much more expensive--a turbine with half the HP of a larger engine has nearly all the materials and almost as much labor, so it's much more than half the cost.   

       Part of the concept of an electro-hybrid car is that the engine can run at its best speed while recharging the batteries. Varying the amount of power generated is not needed--two engines are not needed. It already has power options of (1) battery only, (2) engine only, (3) engine and battery, and (4) engine while charging battery.   

       If this car were to run on multiple turbines, the battery pack could be smaller, or eliminated altogether, yes. You might as well drive it mechanically, with no generator. But then you have the classic turbine-car problem made even worse.   

       When turbine cars (non-hybrids) were tried, they had very poor acceleration. Which was because the drivers would slow the engines down to idle, then punch the throttle, expecting the engine to both spool up and to drive the car. (They should have kept the engine wound up, then engaged the clutch.) This system will make that even worse, as it will require that, when a burst of power is needed, the extra engines must be started up, warmed up, spooled up, then hooked up. That is going to take up a lot of time up. Word up.   

       Multiple turbines multiplies all the problems with turbines. The high cost goes even higher, the slow response gets even slower, . . ..
baconbrain, Mar 16 2008

       A really small ice cream cone?
WcW, Mar 17 2008

       I don't understand this, but what came into my mind as I was reading, was a gas-electric hybrid car whose battery was partially charged by the wind of its own movement!
qt75rx1, Mar 17 2008

       Volvo had a concept along these lines. The turbine's output was, I think, about 60kw.
elhigh, Mar 17 2008

       The best strategy when posting ideas here is to research your subject thoroughly and really know what you're talking about.   

       Another fairly good (and more common) strategy is to know a little, but speak with absolute authority.   

       Knowing very little, asking for input from people who do know and repeatedly using the word "might" is a refreshingly honest approach but is sadly doomed to failure.
wagster, Mar 17 2008

       About 15 years ago I had this very same idea, of using turbines to "perpetually" charge the battery pack. [+] for semi-great minds thinking alike.
Noexit, Mar 17 2008

       I like it, but small turbines aren't any more efficient than larger ones: 25pct (as opposed to 35pct for ICE engines).   

       So, you could have yer battery-powered city-car with a lightweight turbine as backup in case you go over range.
FlyingToaster, Mar 17 2008

       The greatest advantage of a turbine is when you can spool up N1 to 90% while sitting in a traffic jam and watch everybody scatter.
lurch, Mar 17 2008

       I don't know what year or model, but there is an 8cyl caddy that will shut fuel off to four of the pistons when at "cruising speed". Sounds kind of like the multi-turbine use-only-what-you-need Idea. Ineffenciency is a problem all machines suffer from. I'm sure your microturbines will not show any note-worthy gain over any other engine. Suffice it to say, if there was a revolutionary way to make alot of energy (Kinetic, Thermal, Electric, what-have-you because they are all the same) with less fuel, it would be done already. A new fuel (and batterys are not new) is the only possible way to revolutionize the automotive industry.   

       And, Noexit, there is no such thing as a perpetual motion machine. Energy can niether be created nor destroyed, and any change of energy from one form to another through a mechanical process, apart from a 100% efficient machine (which does not exist), will lose energy.
MikeD, Mar 19 2008

       [MikeD] radical alternatives to the internal combustion engine could lead to more efficient engines, but too much R&D is required to bring a basic engine to the point where it is as efficient and reliable as today's engines that have over 100 years of evolution behind them. Imagine that someone produced an engine which was 4 times as efficient in theory, but the working prototype was about as efficient and reliable as an engine from the 50's. The inventor may have achieved in 5 years what it took the rest of the world 50 years to create, but he is still 50 years behind.
marklar, Mar 19 2008

       I could concede to this point [marklar] just on principle. Although the rotary engine seams to have flourished well, despite the fact that not a one "shade-tree" mechanic I know can work on one.   

       I wonder what kind of gains you could see in feul effeciency if the engine (standard v-n/I4) was mounted straight up and down to conserve angular momentum while rounding a corner?   

       By the way, do you sell books on amazon.com? I think I remember that name from a book I purchased ... Sarte? Maybe?
MikeD, Mar 20 2008


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