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Operation Section
Alarms and Shutoffs
• Protection from detonation
Switches
The engine is installed with the following switches.
• High cooling water temperature switch
• Low oil pressure switch
• High pressure switch for the manifold
Governor
The engine is installed with a digital governor that
includes the following components:
• Digital governor
• Actuators and throttle valves
• Magnetic pickup
• Wiring harness
The governor uses the magnetic pickup to sense
engine speed from the flywheel gear teeth. This
signal is fed into the governor, which drives an
actuator. This is connected to the throttle valves in
order to control the amount of combustion gas/air.
A DC Desk service tool with the appropriate software
key and cable are required in order to perform any
adjustments to the system.
Detonation System
The equipment for the detonation system senses
detonation or knock which may be caused by poor
gas or may be caused by high combustion
temperatures.
The detonation system includes the following
components:
• Detonation sensor on each cylinder
• Control module for detonation
• Wiring harness
The detonation system operates by measuring
vibrations on the crankcase. The signal is processed
in order to eliminate normal engine vibrations. If
detonation above a predetermined level is detected
the ignition timing is retarded. If detonation ceases,
the ignition timing that is retarded will be gradually
brought back to a normal value. If the engine
continues detonation the detonation system will
operate in order to stop the engine.
Alarms and Shutoffs
The OEM will supply this system. Refer to the OEM
for more information.
Engines may be equipped with optional engine
protective devices that are not included in this
section. This section contains some general
information about the function of typical engine
protective devices.
Alarms and shutoffs are electronically controlled. The
operation of all alarms and shutoffs utilize
components which are actuated by a sensing unit.
The alarms and shutoffs are set at critical operating
temperatures, pressures, or speeds in order to
protect the engine from damage.
The alarms function in order to warn the operator
when an abnormal operating condition occurs. The
shutoffs function in order to shut down the engine
when a more critical abnormal operating condition
occurs. The shutoffs help to prevent damage to the
engine.
Shutoffs may cause unburned gas to remain in the air
inlet and in the exhaust manifold.
Unburned gas in the air inlet and exhaust system
may ignite when the engine is started. Personal
injury and/or property damage may result.
Before starting an engine that may contain un-
burned gas, purge the unburned gas from the air
inlet and exhaust system. Refer to the topic on
purging unburned gas in the " " Starting the Engine" "
section.
If an engine protective device shuts off the engine,
always determine the cause of the shutoff. Make the
necessary repairs before attempting to start the
engine.
Become familiar with the following information:
• Types of the alarm and shutoff controls
• Locations of the alarm and shutoff controls
SEBU8430-02
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