Blue Bird Coachworks 450 LXi, Owner'S Manual

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5-1 Engine Operation
450 LXi Owner Manual
~ 5-1-10 ~ Rev. “C”
Each cylinder has one unit injector. Individual unit injectors meter the fuel. The individual unit injectors also pump the fuel.
The metering and the pumping is done under high pressure. High injection pressures help to reduce fuel consumption and
emissions. The use of this type of unit injector provides total electronic control of injection timing. The injection timing varies
with engine operating conditions. The engine performance is optimized in the following areas:
Starting
Emissions
Noise
Fuel Consumption
Driveability
The timing advance is achieved through precise control of the injector fi ring. Engine speed is controlled by adjusting the fi ring
duration. The information is provided to the Engine Control Module (ECM) by an engine speed/timing sensor. The information
is for detection of cylinder position and engine speed.
The engines have built-in diagnostics in order to ensure that all of the components are functioning and operating properly.
In the event of a system component deviation from the programmed limits, the operator will be alerted to the condition by a
CHECK ENGINE/DIAGNOSTIC lamp that is mounted on the dashboard. An electronic service tool that is provided by Caterpillar
or the cruise control switches (if equipped) may be used to read the numerical code of the diagnostic fl ash code. There
are three types of diagnostic codes: ACTIVE, LOGGED, and EVENT. These codes are logged and stored in the ECM. Refer to
“Engine Diagnostics” section of this manual for additional information.
The cooling system consists of the following items: a centrifugal pump that is driven by a gear, water temperature regulator,
an oil cooler, and an OEM supplied radiator that incorporates a shunt system.
The engine lubricating oil is supplied by a gear type pump. The engine lubricating oil is cooled and fi ltered. Bypass valves
provide unrestricted fl ow of lubrication oil to the engine parts when the oil viscosity is high or if either of the oil cooler or the
oil fi lter elements (paper cartridge) become plugged.
Engine effi ciency, effi ciency of emission controls, and engine performance depend on adherence to proper operation and
maintenance recommendations. This includes the use of recommended fuels, coolants and lubrication oils.
5-1.4.1 Multitorque Rating
(If Equipped)
The Multitorque ratings provide additional torque as engine load increases. This feature provides higher torque levels. This
feature also provides better driveability while the vehicle is only in the top gears. The engine electronics are able to determine
when the vehicle is in the top gears by calculating the engine rpm/vehicle speed ratio.
With the additional torque, the following benefi ts are provided: less shifting in rolling terrain, less wear on drive line
components, more responsive, and better engine performance.
5-1.4.2 Aftermarket Products and Caterpillar Engines
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When auxiliary devices, accessories, or consumables (fi lters, additives, catalysts, etc.) which are made by other
manufacturers are used on Caterpillar products, the Caterpillar warranty is not affected simply because of such use.
However, failures that result from the installation or use of other manufacturers’ devices, accessories, or consumables are
NOT Caterpillar defects. Therefore, the defects are NOT covered under the Caterpillar warranty.
NOTICE: In order to maximize fuel system life and prevent premature wear out from abrasive particles in the
fuel, a two micron absolute high effi ciency fuel fi lter is required for all Caterpillar Hydraulic Electronic Unit Injectors.
Caterpillar High Effi ciency Fuel Filters meet these requirements. Consult your Caterpillar dealer for the proper part
numbers.