10
ENGINE SYSTEMS
One piece aluminum alloy pistons are fitted with
one keystone cut compression ring, one rectangular
intermediate compression ring, and a two piece oil
control ring.
The combustion bowl (in the piston
crown) reduces exhaust emissions.
The camshaft is supported by five insert bushings
pressed into the crankcase.
Two cam lobes, cam
followers, push rods and valve bridges control four
valves per cylinder.
The camshaft is gear driven
from the rear end of the crankshaft. A thrust flange
is located between the camshaft gear and the
crankcase. Camshaft thrust is controlled with the rear
surface of the number 5 cam journal and the cam
gear.
Hydraulic cam followers maintain zero valve lash
and minimize engine noise. This eliminates periodic
adjustment of valve lash. The hydraulic cam followers
have rollers which provide excellent cam lobe and
cam follower durability.
The lubrication system uses a crankshaft driven
gerotor pump mounted on the front cover. The oil
pressure regulator is built into the front cover and
is accessible from outside the engine.
Lube oil is
routed through an oil cooler equipped with a pressure
controlled bypass valve.
Lube oil moves through
passages in the crankcase to lubricate all internal
components and to supply the piston cooling tubes
and high pressure pump reservoir. The VGT and air
compressor use external oil lines.
The VGT is electronically controlled and hydraulically
actuated. The VGT provides boost control at low and
high speeds for improved throttle response.
An exhaust gas recirculation valve allows water
cooled exhaust gases to be fed into the inlet air
stream to reduce exhaust emissions.
A closed crankcase breather system recirculates
crankcase vapors back into the intake air system.
A chassis mounted Charge Air Cooler (CAC), an
air-to-air heat exchanger, increases the density of the
air charge.
Engine operation is controlled by two engine mounted
control modules:
•
Electronic Control Module (ECM)
•
Injector Drive Module (IDM)
The ECM receives signals from engine and chassis
mounted sensors.
The ECM controls engine
operation with the following actuators:
•
IPR
•
VGT control valve
•
EGR
•
Glow plug relay
The IDM controls fuel injector operation using data
from the ECM.
EGES235-2
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© 2006 International Truck and Engine Corporation
