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Originally Posted by jamesqf
Oh? Have you told Intel about this?
Why's the train energy-efficient, though? Think about it: you have two main sources of frictional loss, air friction and rolling friction. Air friction depends mainly on cross sectional area, and the area of a train is only about 3-4 times that of a semi, no matter how long it is. For rolling friction, instead of a semi's rubber tires flexing on the rough road, you've got solid steel wheels on smooth rails.
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Yes but that isn't the whole story. You saw the drag doesn't scale comment? Right?
Read an old article called
"Economies of Scale; comparing the boat, the train, and the semi"
Like it or not larger more expensive LARGER devices always get more attention to efficiency. The train does get more of its fuel converted into power to its wheels independant of of outside drag compared to a car, as does a boat to its prop.
The Most Powerful Diesel Engine in the World
How many cars do you see with verified 50% efficiency motors? The theoretical max is only 56%!
It is very commonplace for trains that have motors in excess of 40% efficiency, (most in "hi end" consumer range vehicles hover in the 30% area when lucky). The train also gets more of its power to its wheels as the drivetrain is more efficient compared to a typical car setup and this is before outside drag. This should show that there are things that can be done and that there is hope for improvement in the automotive sector.
Admit it, we usually build larger devices better with more recovery systems in place. There are large ships with 3 recovery phases, you would never see that possible on a car, train or a semi. Nor would you ever see 50% efficiency on the motor end either.
A few are mentioning recovery in normal channels
5 Ways to Reclaim Engine Heat and Deliver More Efficient Cars « Earth2Tech
Honda only gets about 3.8% back But every little bit counts. If we can get consumer level motors up to 50% efficiency that would easily add 50% or more to mpg values on the vehicle without changes to the drivetrain. Not to mention the side effects of needing a smaller motor for the same power, having less massive suspension, etc.