A piston engine is an energy converter. It is woefully inefficient,
most of the energy in the fuel goes into the water jacket as wasted
heat. Some of the energy is consumed in friction losses, etc. A small
percentage moves the car. All engines have a power band (rpm range) in
which they operate most efficiently, converting more of the fuel's
energy into power to move the vehicle. This being true, the engine will
develop the necessary power to keep the vehicle going with a smaller
relative throttle opening than in other RPM ranges. Overdrives allow
you to operate the engine within this power band, at somewhat higher
speeds and at fewer revs per mile for the given engine RPM range. With
the engine operating in its most efficient RPM range for a shorter time,
there has to be a reduction in fuel consumption.
CR
john c kahoon wrote:
>
> One thing is equal, it take "x" amount of force to move a vehicle of a
> certain weight at a certain speed.
>
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