Advantages of Exhaust Gas Turbocharging
Compared with a naturally aspirated engine of identical power output, the fuel consumption
of a turbocharger engine is lower, as some of the normally wasted exhaust energy contributes
to the engine's efficiency. Due to the lower volumetric displacement of the turbo
engine, frictional and thermal losses are less.
The power-to-weight ratio, i.e. kilowatt (power output)/kilograms (engine weight),
of the exhaust gas turbocharged engine is much better than that of the naturally
The turbocharger engine's installation space requirement is smaller than that of a naturally
aspirated engine with the same power output.
A turbocharged engine's torque characteristic can be improved. Due to the so-called
"maxidyne characteristic" (a very high torque increase at low engine speeds), close
to full power output is maintained well below rated engine speed. Therefore, climbing
a hill requires fewer gear changes and speed loss is lower.
The high-altitude performance of a turbocharged engine is significantly better.
Because of the lower air pressure at high altitudes, the power loss of a naturally
aspirated engine is considerable. In contrast, the performance of the turbine improves
at altitude as a result of the greater pressure difference between the virtually
constant pressure upstream of the turbine and the lower ambient pressure at outlet.
The lower air density at the compressor inlet is largely equalized. Hence, the engine
has barely any power loss.
Because of reduced overall size, the sound-radiating outer surface of a turbocharger engine
is smaller, it is therefore less noisy than a naturally aspirated engine with identical
output. The turbocharger itself acts as an additional silencer.