[LgWoodenBadger]

I think a more apt comparison would be with a Diesel-Electric locomotive. They're already the kings of transportation efficiency (or possibly a close second to container ships).

I don't know why tractor trailers haven't followed this same diesel-electric pattern. Max torque from 0 RPM plus the elimination of 18 speed manual gear boxes?

[mschuster91]

> I don't know why tractor trailers haven't followed this same diesel-electric pattern.

A high-load tractor trailer can deliver around 500 kW of power. I believe the main problem is that there is no wheel-mountable motor available to transfer that kind of power. The Tesla, for example, is rated 345 kW peak in the P85D, but a tractor trailer needs this amount of power continuously. When we do the math and assume 500V (which is a ridiculous high voltage anyway!), you'll need 1000A-rated cables, switches and motors/generators.

That's not your home 2.5mm2 cable, and discarding the waste heat (assuming 95% end-to-end efficiency) at this scale is a hard task as you have, essentially, a rolling 25 kW heater.

With ships there is MASSIVELY more space available, and the heat can be (and often is) used for heat distribution, and a diesel loco also has lots of space available to put components in.

A loco can take up to eight times the same space as a single tractor-trailer...

[walrus01]

In ships a portion of the waste heat from the engine is also used to pre-heat the fuel tank and lines to make it easier to pump, as heavy bunker oil is extremely thick at 'room' temperature.