Ok so with all of the inefficiencies of the reciprocating internal combustion engine why don’t they make a hybrid car powered by a small centrifugal turbine that would work like an aircraft APU. The car would have an all electric drive system and the turbine would produce electricity for the electric motor. The FADEC computer would control fuel flow to the turbine as more power was needed. Trains have been doing this for decades so why not cars? A plus would be that you could use any liquid or flammable gas for fuel.
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Why Not A Turbine Powered Hybrid Car Similar To An Aircraft Apu?12 comments to Why Not A Turbine Powered Hybrid Car Similar To An Aircraft Apu? |
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As turbines get smaller, they get less efficient.
A 500hp PT6 turbine used .58 lbs of fuel per horsepower per hour, and the engine of an SUV gets about .55.
A 300hp turbine uses about 1lb for ever hp per hour, and a 130hp turbine uses about 3lbs per hp per hour.
There are some cheap turbine engines out there that use parts from turbochargers, but they use nearly 10lbs of fuel for every horsepower they produce per hour.
Those little jet engines in models use a ridiculous amount of fuel for the power they produce, some consume 15 gallons and hour to make 0.8 hp.
Years back they tried a turbine engine in a car found out it generated too much heat and was inefficient at lower speeds.
A train usually accelerates to a certain speed and stays there for most of it’s run, whereas a car in traffic doesn’t. Most freight and commuter trains sill use diesel engines to run the generators.
Might be a good idea but it would have to be a lot of changes to work in a car.
First is the high pitched whine of a turbine and the loud rocket noise. You would need more than a regular muffler to suppress the noise. Regular cars now days are almost as quiet as electric cars so they would have to make it at least as quiet.
The piston engine in a hybrid isn’t on all the time, it starts and stops as needed to charge the batteries and they start in less than a second and using very little electrical power. Turbines started by electric starter take a long time to spool up fast enough to start, then they have to power up a glow plug or igniter to light the compressed fuel. It’ll probably take up to 30 seconds to start it and bring it up to speed. This takes a lot of electrical power that the turbine powered generator has to replenish.
If they overcome these things turbines could be a good alternative to the piston engine. The initial cost would be higher but the maintenance would probably be a lot lower because there’s less moving parts, it’s air cooled, so no radiator or coolant, the oil lubricates only the bearings not the cylinder walls where the viscosity break down and contamination come from.
Piston engines are easier to make because of the bigger tolerances they can get away with and therefore will be cheaper to make which is the bottom line. Money.
A car being driven by the power generated by a small turbine would not have the acceleration problems like a purely turbine powered vehicle, and it could use the traction motors for dynamic braking and power recovery, however….
While the gas turbine has excellent power to weight ratio, it is NOT as efficient as a piston plant (it is nowhere even close). A turbine burns way more fuel for the power it produces. It also costs more to produce and creates much more noise.
As far as I know there were only a few turbine powered trains and none were very successful. The major obstacles to turbine trains were high fuel costs and high maintenance costs. These would be even greater obstacles to overcome for cars.
Turbines are not any more efficient than a reciprocating engine. They are just much lighter for the power they produce. Weight is not as much of a factor in a car as it is in an airplane. Turbines are also much more expensive, so you’d need a huge increase in performance or economy to justify the cost. Trains may be using them but a train has a fairly constant power demand. A hybrid car is shutting off the engine on a regular basis. This leads to the other problem with using a turbine, they take a fair amount of time to start and stop. They run at very high RPM and temperatures, so you can’t just turn it on instantly, you have to spend time and fuel getting it running. There is also a lag of up to one second between power demand and power delivery on a turbine.
The reason large aircraft use turbine APU’s is because they already have jet fuel on board and just need enough juice to get the big turbines going. After that the APU is no longer needed.
In the case of a hybrid system a reciprocating engine is actually better, it plays to the strengths of the engine.
Excellent question!!, yes you could a small jet engine like the ones used in radio control planes, it could power a generator to give electric power to a car. Better yet I think is one of those honda generators powered by a small and economical internal combustion engine to power a car. Yes trains work this way, nobody knows or belive it, but we americans are retarded and will never see any electric car or efficient hybrid.
Jay Leno had a piece about a jet engine powered motorcycle… it was very fast… the only problem came when it was time to slow down… jet engines are not very responsive… they take a while to spool up and even longer to spool down… slamming on the brakes really isnt an option… Not to mention the noise that a jet engine creates… even the tiny APU on a CRJ is loud enough to need ear protection… and we are talking about powering some computers and light bulbs… not driving a car…
They have used it in the M-1 Abrams and works reasonably well in its role.
However in civillian use, it wouldnt be of much benefits. To start with, the fuel efficiency will be hit, GTs are usually run at operating speeds, not much scope for idling. Starting up will be a long process (starting the M1′s GTs takes more than 10 gallons of fuel), diffusion of the jet efflux and sound control would be engineering nightmares.
In return what you get is high reliability, flexible fuel and good power to weight ratio. As of now reliability is pretty good in reciprocating engines and benefits of power to weight ratio is not so pronounced in a road vehicle. Economy, sound control and exhaust control are the ones that makes the GT quite unsuitable for a car.
I remember hearing about a turbine powered car I think it was Ford in the 60′s or 70′s tried it out. As memory serves there was a problem with the turbine blades being TOO fragile because of the size and the materials being used. Also there was a big problem with foreign object damage (FOD) being that it was a car sized vacuum cleaner, I guess the roads would be VERY clean if we used that type of tech.
I’ve think it was VW that used the electric drive you suggested but with a diesel engine driving the genset on a concept car. As far as I know the system worked well but was never put into production. I’ve heard that the Toyota prius uses the gas engine to power the electric motor but I haven’t looked at the tech.
Noise, fuel consumption and heat. No good. the only modern turbine powered vehicle is the Y2K motorcycle. Jay Leno has one. Check it out on youtube. He talks about it.
An APU would be far too powerful to waste driving a generator. Probably use more fuel than a petrol engine anyway…….
But, those small jet engines which are now found on Radio Controlled model A/c could work, driving a generator……. which would also need some form of capacitor to store power that is needed rapidly.
There must be a reason why, otherwise somebody would have done it by now.
If it were to charge batteries, then they need to be as big as the car to be any good. Present electric cars are a sham, and are unsafe (The G Whiz for example).
This is a blast from the past;
http://www.imperialclub.com/Yr/1963/Turbine/index.htm