Teledyne TSIO-360-RB, Maintenance Manual

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11-2
11-1 EXHAUST SYSTEM DESCRIPTION
The L/TSIO-360-RB exhaust system contains the following engine components: rear
mounted turbocharger, hydraulic wastegate, lubrication plumbing, exhaust collector
assembly, and turbocharger tailpipe assembly.
During normal engine operation, exhaust gases exiting the cylinder combustion chambers,
flow through the exhaust collector to the turbocharger turbine housing inlets. The exhaust
gas flow provides turbine wheel rotation and exits through the turbine housing discharge port
and tailpipe assembly. The turbine wheel drives the compressor wheel which is connected
by a common shaft.
Engine manifold pressure is maintained within the specified limits by controlling the
turbocharger compressor discharge pressure.
Compressor discharge pressure (deck pressure) is regulated by controlling the flow of
exhaust gas through the turbocharger turbine. This is accomplished by installing a
hydraulically controlled butterfly type exhaust by-pass valve (wastegate) in the exhaust
system prior to the inlet of the turbine housing. The wastegate butterfly valve is spring
loaded to the open position and closed by pressurized oil from the engine.
Oil flow through the wastegate actuator is controlled by a variable absolute pressure
controller (VAPC) that is mounted to the induction system after the turbocharger
compressor, but before the throttle butterfly valve, sensing compressor discharge pressure.
The controller is mechanically linked to the throttle and using a system of cams, followers
and poppet valves controls oil flow from the wastegate actuator to the engine.
On engine start, the controller senses insufficient compressor discharge pressure (deck
pressure) and restricts the flow of oil from the wastegate actuator to the engine. This
causes the wastegate butterfly valve to close. As the throttle is advanced, exhaust gas flow
across the turbine increases, increasing turbine/compressor shaft speed and compressor
discharge pressure. The (VAPC) senses compressor discharge pressure and as pressure
increases to the selected setting, the controller poppet valve begins to open, relieving oil
pressure to the wastegate actuator. This allows the butterfly valve to move toward the open
position. Exhaust gases by-pass the turbine and the turbine/compressor shaft speed
stabilizes, and compressor discharge pressure stabilizes, maintaining selected manifold
pressure.