5 ms·

Having an ICE that drives a generator (alternator?) to power a traction motor(s), without being mechanically linked to the drivetrain, is how diesel locomotives

by clucas 3y ago

Having an ICE that drives a generator (alternator?) to power a traction motor(s), without being mechanically linked to the drivetrain, is how diesel locomotives operate. I believe the concept also has been (is being?) explored for linehaul trucks. But I'm not sure what constraints there are on passenger vehicles though... I'm also curious. If I had to guess, I would bet that the constraints are more commercial than physical... hybrids are already very efficient, so the market for such a vehicle would probably not justify the engineering costs. But that's just a guess!

linkjuice4all 3y ago
Union Pacific tried using turbines in the 50s[0] but fuel consumption was an issue (I think they had to keep the turbine idling and maybe throttling wasn't as easy?). Also mentioned in the wiki article was the low-grade fuel they were used was able to be used for plastic manufacturing instead of just burning it. The bigger difference between locomotive applications and GPs question is around charging batteries as opposed to running motors or directly turning the wheels. Efficiency of the smaller turbine is mentioned in another comment - but I have to imagine you'd also see some loses going from turbine to generator to battery and then to electric motor. [0] https://en.wikipedia.org/wiki/Union_Pacific_GTELs https://en.wikipedia.org/wiki/Union_Pacific_GTELs
- KennyBlanken 3y ago
  Diesels idle pretty efficiently whereas jet turbines have very high minimum amounts of power. In terms of efficiency losses between the turbine, generator, battery, and motor - no, not really; look at most modern hybrid cars. Lithium ion battery coulombic efficiency is in the high 90's percentage-wise, by the way. I would imagine that we might see hybrid turbine locomotives as battery power density and cost continue to improve.
teeray 3y ago
The MBTA uses jet engines as giant hairdryers to melt snow off the Mattapan High Speed Line [0]. I’m not sure if it’s also serving as the prime mover, but even if not it’s still an interesting and unusual application. [0] https://youtu.be/DL6jKOCeVec https://youtu.be/DL6jKOCeVec

by clucas 3y ago

linkjuice4all 3y ago

Union Pacific tried using turbines in the 50s[0] but fuel consumption was an issue (I think they had to keep the turbine idling and maybe throttling wasn't as easy?). Also mentioned in the wiki article was the low-grade fuel they were used was able to be used for plastic manufacturing instead of just burning it. The bigger difference between locomotive applications and GPs question is around charging batteries as opposed to running motors or directly turning the wheels. Efficiency of the smaller turbine is mentioned in another comment - but I have to imagine you'd also see some loses going from turbine to generator to battery and then to electric motor. [0] https://en.wikipedia.org/wiki/Union_Pacific_GTELs https://en.wikipedia.org/wiki/Union_Pacific_GTELs

KennyBlanken 3y ago
Diesels idle pretty efficiently whereas jet turbines have very high minimum amounts of power. In terms of efficiency losses between the turbine, generator, battery, and motor - no, not really; look at most modern hybrid cars. Lithium ion battery coulombic efficiency is in the high 90's percentage-wise, by the way. I would imagine that we might see hybrid turbine locomotives as battery power density and cost continue to improve.

teeray 3y ago

The MBTA uses jet engines as giant hairdryers to melt snow off the Mattapan High Speed Line [0]. I’m not sure if it’s also serving as the prime mover, but even if not it’s still an interesting and unusual application. [0] https://youtu.be/DL6jKOCeVec https://youtu.be/DL6jKOCeVec