Navistar MaxxForce DT 9, Operation And Maintenance Manual

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SECTION 1 – ENGINE SYSTEMS
Engine Description (cont.)
Crankshaft
The crankshaft has seven main bearings with fore and aft thrust
controlled at the rear bearing. One fractured cap connecting rod
is attached at each crankshaft journal. The piston pin moves
freely inside the connecting rod and piston. Piston pin retaining
rings secure the piston pin in the piston. The rear oil seal carrier
is part of the flywheel housing.
Cylinder Head
The cylinder head has four valves per cylinder with centrally
located fuel injectors directing fuel over the pistons.
This
configuration provides improved performance and reduces
emissions.
The fuel injection system is electro-hydraulic. The system
includes an under-valve-cover high-pressure oil manifold, fuel
injectors, and a high-pressure oil pump.
The injectors are
installed in the cylinder head, under the valve cover and under
the high-pressure oil manifold.
The water supply housing serves as the mounting bracket for
the refrigerant compressor.
Mounting capabilities for a dual
refrigerant compressor are available as an option. The pad
mounting design of the alternator and refrigerant compressor
brackets provide easy removal and improved durability.
Electronic Control System
An Engine Control Module (ECM) monitors and controls sensors,
actuators, and valves to ensure maximum engine performance
and compliance with EPA emissions requirements.
The Crankshaft Position (CKP) sensor and the Camshaft
Position (CMP) sensor are used by the ECM to calculate rpm,
fuel timing, fuel quantity, and duration of fuel injection.
Fuel System
The low-pressure electric fuel pump draws fuel from the fuel
tank through the fuel filter housing. The housing includes an
electric fuel pump, strainer, filter, drain valve, Water in Fuel
(WIF) sensor, and Engine Fuel Pressure (EFP) sensor.
If
equipped, an optional fuel heater element is located in the fuel
filter housing. Conditioned fuel is pumped through the intake
manifold and cylinder head to the fuel injectors.
The WIF sensor detects water in the fuel system. When a
programmed value of water is collected in the fuel filter housing,
the FUEL FILTER lamp will illuminate. The collected water must
be removed immediately. The water is drained by using the
drain valve located on the fuel filter housing.
Form No. 1172040R1
Page 18
Printed in the United States of America