Cessna T182 1982 Pilot Operating Handbook page 153

SECTION 7 CESSNA
AIRPLANE
&
SYSTEMS DESCRIPTIONS MODEL T182
The following steps, when combined with the turbocharger system
schematic (figure
7-5),
provide a better understanding of how the turbo ­
charger system works. The steps follow the induction air as it enters the air
filter and passes through the engine until it is expelled as exhaust gases.
1.
Air from the slipstream enters the induction system through a
recessed opening in the left engine cowl, passes through a filter,
enters a carburetor heat airbox, and is then ducted into the
compressor side of the turbocharger.
2. The compressed air is then forced through the carburetor and
induction manifold into the cylinders.
3. The fuel/ air mixture is burned and exhausted to the turbine side of
the turbocharger and/ or overboard, depending on the position of
the waste gate.
4.
Exhaust gases drive the turbine which, in turn drives the compres­
sor, thus completing the cycle.
It can be seen from studying steps 1 through
4
that anything which
affects the flow of induction air into the compressor or the flow of exhaust
gases into the turbine will increase or decrease the speed of the turbo­
charger. This resultant change in flow will have an effect on the engine.
However, if the waste gate, is still open, its position can be changed
manually with the throttle control (figure
7-5)
in order to maintain a
constant compressor discharge pressure.
The compressor has the capability of producing manifold pressures in
excess of 31 in. Hg. In order not to exceed the maximum, manifold pressure
should be monitored closely and the throttle control adjusted as necessary
to maintain 31 in. Hg. if maximum continuous power is desired. Full open
throttle control will not be necessary to maintain maximum continuous
power (31 in. Hg.), with the possible exception during hot day conditions at
high altitude.
MANIFOLD PRESSURE VARIATION WITH ENGINE RPM
The turbocharged, carbureted engine will react just the opposite of a
normally aspirated engine when the RPM is varied. That is, when the RPM
is increased, the manifold pressure will increase slightly. When the RPM is
decreased, the manifold pressure will decrease slightly.
MANIFOLD PRESSURE VARIATION WITH ALTITUDE
Manifold pressure will vary with altitude similar to a normally
aspirated engine. Manifold pressure will decrease with altitude unless the
throttle control is advanced. The turbocharger has the capability of
maintaining in excess of the maximum continuous manifold pressure of 31
in. Hg. Since the waste gate is manually controlled. the throttle control will
7-22
21 August 1981