[B][U]The question:[/U][/B] If an ICE range extender primarily operates at road speed, would a turbine engine provide any efficiency advantage over a piston engine?
[B][U]The background:[/U][/B] I’ve been mulling over powerplant options for the hybrid portion of a DIY hybrid, and I started thinking about a small turbine engine.
The advantage, as I see it, is that the EV motor would handle in-town driving and the hybrid component would be there for additional power for highway speed and longer trips. Since the hybrid motor would only be needed at road speeds, the power lag as the turbine spools up would be a minimal factor.
Ideally, the turbine would provide mechanical energy to the drive wheels and also power a recharging system. Also, if feasible, exhaust gasses could be used to power a secondary turbo that could drive additional generating capacity.
There’s a motorcycle manufacturer who uses decommissioned helicopter engines to make absurdly overpowered bikes, but I was thinking of a smaller turbine engine than that to provide supplemental power to an EV. The bike maker’s site is: MTT - Leading Turbine Innovation
You know what turbines might be a good choice for a hybrid EV. I am a an electrical engineer, not a mechanical engineer and have thought about this.
Turbine engines are not as efficient as ICE, but they are very simple, reliable, and very compact with light weight for the amount of power they produce. So what I am thinking is use a turbine to run a generator with a small battery bank to operate a full size electric motor. You would not need a very large heavy battery bank to get distance and power capacity as the turbine generator would generate that.
What I do not know because I am not an mechanical engineer is if it would beat the Diesel engine efficiency with the same hybrid concept because diesels are very reliable, have tremendous torque/power to run a generator/battery combo.
What I do know is a gasoline ICE hybrid is not the answer.
The the main killer for turbine engines is that they have not been as reliable as ICE to my knowledge. I’ve heard that they are hard to start in some situations, such as cold weather. I’m not certain about the efficiency issue, that may be a thing of the past. The other problem is this still relies on a combustion engine. That needs to end.
Apparently in the 60’s they were capable of producing turbine powered cars that were able to get 22MPG. Unfortunately, according to the article, the government caused the project to be scrapped.
[QUOTE=Jebnar;6546]
Apparently in the 60’s they were capable of producing turbine powered cars that were able to get 22MPG. Unfortunately, according to the article, the government caused the project to be scrapped.[/QUOTE]It is true and the really scary thing now is our government is now socialist and has full control of the auto manufacture industry.
FWIW it is our government that has and will continue to block efforts to prevent EV’s from becoming anything more than a fad or niche market. Our government would loose about $40 billion a year from tax losses in fuel taxes. States would also loose out big time too as most states collect more than fed.
Another good example of our government not wanting fuel efficient vehicles is emission regulations and blocking diesel light transportation vehicles. Every time a manufacture prepares to release a 50 state diesel in the USA market, the EPA changes the emission standard to block it. A good example is the Honda Accord that was set to be released in 2006, now rescheduled for 2011; however EPA will up the bar again to block it. I mean who in their right mind would want a nice vehicle that gets 50 MPG, great acceleration, bells and whistles and far cleaner burning than gasoline ICE.
Political musings aside, it looks like a piston engine may well be the way to go.
I did some more research and found that the efficiency of a turbine jet engine comes from a relatively small gas turbine driving pretty big fans that push air. That’s good for developing thrust for aircraft but not so much when looking to power wheels.
I am an instrument control and electrical tech in a combined cycle and simple cycle gas turbine power plant. The only way they are even close to being efficient is if you can take advantage of the waste heat they produce. Our combined cycle is pretty efficient but it is a combined cycle because we run the waste heat from the turbine through a heat recovery boiler and run a steam turbine off of it. The simple cycles aren’t efficient at all. We use them for peaking loads when you don’t really care about how much it costs. They have a small foot print and can give us 50MW each in 15 minutes. They also have high maint. costs vs an ICE. They have their place they just haven’t developed anything small enough and rugged enough for the general consumer. The day that they make a gas turbine the size of a coffee can that makes 25hp and can be overhauled in a garage for less than 100 bucks, now we are talking. The we would just need to deal with the fuel consumption. The good thing about a gas turbine is it will run on anything that will burn.
[QUOTE=Seafarer12;6600] They have their place they just haven’t developed anything small enough and rugged enough for the general consumer. The day that they make a gas turbine the size of a coffee can that makes 25hp and can be overhauled in a garage for less than 100 bucks, now we are talking. .[/QUOTE]Well I think they are already here. You can buy them for RC airplanes about the size of your palm.
I know of a few galf carts that have turbine engines that run 80 MPH. I agree effeciency is an issue, and expense is another issue. But the micro and mini sizes has been araound for a long time.
This one is a little large and expensive, but it is coffee can size.
The only ones I have seen for R/C planes are just a regular prop engine inside a duct and not a true turbine. They might have something new out, it isn’t something I keep up to date in.
I know they have small turbines for the drones the military uses. I haven’t actually seen a small gas turbine that would drive a generator. The problem with a small gas turbine would be a control system and fuel delivery system. They would take up more room than the turbine.
I read an article about a self taught mechanic in Kansas (I think) that messes around with alot of different vehicle conversions. The article focused on some Hummers he did (H1 and H2 that people were blown away with). He was also building an H3 that was supposed to be able to reach 60 mpg (on diesel) and around 60mpg with other combustable fuels. He took an electric motor, batteries, and some super capacitors and dropped them into the engine bay. He was in the process of putting the genset in. I am not sure what generator he was using but the article said he had bought a 1985 US Army helicopter turbine to power it. Supposedly when the vehicle was low on power he would be able to fire up the turbine and generate enough power to recharge the system in 30 sec or so.
Where very high power-to-weight ratios are required ICE is the best, as his acts as a gas turbine in this case. Its major application is in Electric generators.