Inlet Air Heater System - Navistar N13 Service Manual

Airflow
Air flows through the air filter assembly and enters
the Low-Pressure (LP) turbocharger.
turbocharger increases air pressure and temperature
before entering the Low Pressure Charge Air Cooler
(LPCAC). Cooled and compressed air then flows from
the LPCAC into the High Pressure (HP) turbocharger
(compressor inlet). Hot and highly compressed air
flows from the HP turbocharger (compressor outlet)
into the High Pressure Charge Air Cooler (HPCAC)
where it is cooled, and into the intake throttle duct,
and continues through the Engine Throttle Valve
(ETV). The HP and LP turbochargers can increase
pressures up to 345 kPa (50 psi).
If the Exhaust Gas Recirculation Valve (EGRV) is
open, exhaust gases pass through the EGR cooler
and into the intake throttle duct where it is mixed with
filtered air. This mixture flows into the intake manifold,
and then the cylinder head. The intake manifold is an
integral part of the cylinder head casting.
ENGINE SYSTEMS
During cold weather, the Inlet Air Heater system
activates the heater element, vaporizing and igniting
small quantities of fuel into the air inlet duct.
The LP
After combustion, exhaust gases exit through the
cylinder head exhaust valves and ports. The exhaust
gas is forced through the exhaust manifold where,
depending on EGRV position, it is split between
the EGR system and the exit path through the HP
turbocharger, LP turbocharger, and Exhaust Back
Pressure Valve (EBPV).
The EBPV is operated by the Air Control Valve (ACV),
a pneumatic actuator.
the EBPV restricts flow and increases exhaust back
pressure. Operation of the EBPV is controlled by the
ECM using the ACV and the Turbocharger 1 Turbine
Outlet Pressure (TC1TOP) sensor. When the EBPV
is opened, exhaust back pressure is released.
Exhaust gases exiting the engine flow through the
EBPV, then through the vehicle Aftertreatment (AFT)
system, and out the exhaust tail pipe.
When the ACV is applied,
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