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Old 09-12-2008, 03:21 PM   #51 (permalink)
njlou
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Quote:
Originally Posted by Duffman View Post
1) Diesel Engine is more efficient and there is more energy in the fuel
2) Big rig engines operate in an efficient narrow band
3) Low power to weight ratio
4) Better Driving habits and bulk of the time spent cruising
5) Aero Drag is smaller on a per pound basis (being both heavy and long are advantages here)
6) Semis are optimized to reduce cost of operation above all other criteria.
You are correct - Here are some more:
- The big Diesels are more efficient and use more powerful fuel. Since they need big engines anyhow, they can use large/efficient ones.
- They have (little) pollution controls
- Gearing is a major helper and the big rigs have the room and the budget for them.
- they are on the highway at highway speeds. If they drove to the grocery store or around town they would get gallons to the mile.
- yes they drive more conservatively simply due to size.
- BTW locomotives use the diesel/electric propultion systems. the diesel is computer controlled to run a generator at peak efficiency. In effect it IS a hybrid. It is a multi ton Prius???LOL.

Here is another comparison - Why do some old British tiny cars including sports cars get miserable (teens) MPG?

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