Alfonso wrote:

Sorry for my ignorance, but, what is a charge-cooled engine?

When talking about engines, the "charge" is the fuel & air mixture.  A
"charge cooled" engine draws the fuel & air mixture through the innards
of the engine, allowing the fuel evaporation cooling effect to cool the
engine. One (of the many) downsides of this is that the charge density
is reduced.  More charge density means more potential power (this is
what turbochargers accomplish), so a reduction in charge density means a
reduction in the potential power output by the engine.

Regards,
Russell Kent