Thanks for this, Chuck! We seem to be continuing our more than century-old love affair with automobiles. Maybe that is having a strong effect on our new designs.
I'm not a powertrain engineer, but perhaps yourself or others can help me out. It's my layman understanding that modern Diesel locomotives are Diesel-Electric hybrids, having a very efficient Diesel-fueled turbine that does one thing well... it turns an electric generator. Because the turbine does one thing well, it can be optimized for power, torque, fuel-consumption, etc. to produce electricity. The electricity is then used to power the traction motors that have no mechanical transmission or clutch -- all through the magic of magnetic field induction. The electric motors do one thing well, they turn the drive shaft. As far as power goes, Wikipedia lists that a modern Diesel locomotive can start moving trains weighing in excess of 15,000 tons. The M1 Abrams tank uses a 1,500-hp gas turbine engine, but uses a mechanical hydrokinetic transmission.
I continue to be perplexed as to why the Automobile industry does not integrate technology that has been successfully developed by other industries. I would have thought that General Electric would have used their turbine expertise to capture the automobile market by now. And I don't know about you, but as far as keeping the motorheads happy, if folks get excited about a "turbocharged" engine, I would love to be on the marketing team for the first "turbine jet" powered commercial automobile...
williamweaver, Diesel Electric Locomotives are similar to hybrid cars except for one thing, the battery. This is changing, of course. Even though they are very efficient, making them more efficient is worthwhile, considering how much they are used. Actually, GE is taking the next step and putitng in batteries. These can be charged during operations and can recover energy while braking. They then provide low speed power which is more responsive than the diesel gen set.
As for turbines in cars, it has been tried. A maker of microturbines, Capstone, ran a test of a 10kw microturbine genset in a small car a couple of years back. Looking at their web site now, they do have gensets, 30kw and 65kw, for larger vehicles, like busses. These cost more to buy, but are much cheaper to maintain and get much better mileage than standard diesel engines. I don't have any information on why the smaller turbine project was not pursued. If these types of systems were used for trucks and busses, though, it would lower our use of fuel overall. In addition, they can run on multiple fuels, liquid and gas. My experience was with gas, but they can also use diesel and kerosene. Perhaps in the future they will be sized for automobiles.
I believe Chrysler had a turbine car in the early Sixties. It had a number of new technology problems, but I think the biggest issue was that a turbine engine needs to spool up, so acceleration was rather poor. If only they made merge lanes as long as runways.
The most famous turbine engine, of course, was the one in Parnelli Jones' car at Indy in 1967. The car left the race with three laps to go when a transmission bearing broke. I believe turbine engines were barred from Indy races afterward.
Personally, Bill, I'd be happy just to see the U.S. car industry make more use of diesel technology. Diesel fuel has about 10% more energy per volume than conventional gasoline. The problem, though, is that diesel engine technology is more expensive. One industry engineer told me that the base diesel engine is about 2X as expensive to make as a regular gasoline engine.
Thanks for that tekochip. That's why I'm wondering why we don't use turbine technology to charge / recharge the batteries of a modern hybrid. Not being an engineer, I find statements like "the relatively constant torque of an electric motor, even at very low speeds tends to increase acceleration performance of an electric vehicle relative to that of the same rated motor power internal combustion engine" (Wikipedia) promising. Instead of developing new transmission technology to mechanically couple the output of the turbine to the differential, it seems an obvious mashup to use an efficient turbine to generate electricity for a modern electric car.
And Chuck, all the more efficient if we use diesel. I've read of several "gas" turbines that accept methane, gasoline, kerosene, diesel, and Jet A. Now I just need to develop one...
"The Jaguar C-X75, the concept that debuted at the 2010 Paris Motor Show, is an electric hybrid that uses two small gas-powered turbines to generate electricity when the battery is low. Looking at the stats, it's an impressive ride: an estimated fuel economy of 41.1 mpg, 778 horsepower, 0 to 62mph in 3.4 seconds, and a top speed of 205 mph."
Looking at some of the MPG ratings that are stated in the slideshow, and checking some online, where is the fuel economy? I have a 1990 GMC Suburban 5.7L that I can get upto 20 MPG by just using good driving habits to maximize mileage. I have a 1968 Tempest with a 5.7L that I have been able to get 21 MPG with good driving habits. I realize that these would get even better mileage by using the same driving habits. But the cost of this research and development is improving thesevehicle MPG by about 5 - 7 MPG. That is 20%, not bad, but still a long way off from 51.4 MPG!
I got to thinking, what is the energy content in one gallon of gasoline and how much work can it generate to move a 4000 pound vehicle? The process of electrification is only covering up the conversion problem. As William pointed out, how about optimizing the conversion by using turbine poweres generators. Seems this is a idea that needs some more thought.
GTOlover, this is one of my favorite Wikipedia Pages http://en.wikipedia.org/wiki/Energy_density. I agree with you in separating the variables. One is the variable of how much Total Energy can you carry on board in the form of fuel while you are traveling and a second variable is how efficiently can the energy in the fuel be Converted into kinetic energy of the vehicle. I think the automobile industry is currently suffering from the "Opportunity Costs of Legacies". We've been doing the same thing for such a long time that it is proven technology, accepted by the regulators, entrenched in our supply chains, and there is a huge activation cost for thinking outside the 20th-century box. We don't keep an account of Opportunity Cost, but I would anticipate that the cost savings we are missing out on by drowning in our current technological inertia would far outstrip the actual costs of not innovating...
Being a huge railfan, I have to tell you that modern diesel electric locomotives do not have turbines. They feature traditional piston driven diesel engines connected to an alternator. I believe the the General Electric locomotives feature four stroke diesel engines, while the Electro-Motive Diesels (a.k.a EMD) (formerly owned by General Motors) feature two stroke diesel engines. Both manufactures utilize turbo charging.
I sure like the sound of the EMDs better than that of the GE's.
It was interesting that there was a horsepower race by the locomotive builders about ten years ago, and it ended with both companies making 6000 horsepower locomotives. Ironically, they both seemed to have problems and lost favor with the railroads. They both now produce their largest units with about 4500 horsepower, which seems to be the sweet spot. Since additional locomotives can be attached together to be operated by lead locomotive (MU'd meaning Multiple Units), more locomotives can be added when they need extra power.
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