The diesel engine operates differently from the conventional gasoline engine.
Gasoline engines control engine speed using a butterfly throttle plate controlling
air/fuel mixture inlet flow. As the throttle plate opens, vacuum created by the pis-
ton velocity draws the metered fuel/air charge into the combustion chamber, then
ignites from a controlled electric ignition source. Closing the throttle plate limits
the fuel/air supply, slowing engine speed, increasing intake manifold vacuum.
The diesel engine in the motorhome controls engine speed by varying fuel
supply only. No throttle plates are used. An exhaust driven turbine system (tur-
bocharger) compresses the fresh air supply into the engine. The fuel is injected
under pressure into the combustion chamber. Ignition of fuel/air charge occurs
from heat generated by rapid high compression. The turbo boost gauge registers
amount of intake manifold compression measured in lbs./in². Therefore, no intake
manifold vacuum exists.
Diesel engine RPM (revolutions per minute) operating speeds are generally
much lower than that of the gasoline engine. Peak torque and horsepower output
values occur at much lower engine speeds. Idle speeds between the two engine
types are similar, however maximum engine speeds are quite different. The gasoline
engine generally is not regulated to a maximum engine speed. The maximum
engine speed on a diesel engine is controlled by an engine speed governor set by
the engine manufacturer.
WARNING: Do not operate a diesel engine where there are or
can be combustible vapors. Vapors can be drawn through air
intake system and cause engine acceleration and over-speeding,
resulting in fire, explosion and extensive property damage.
Numerous safety devices are available, such as air intake shut-
off devices, to minimize risk of over-speeding where an engine
(due to its application) might operate in a combustible environ-
ment, such as fuel spills or gas leaks. Equipment owner and
operator is responsible for safe operation of engine. Consult
your engine authorized repair location for future information.
The maintenance guidelines found in the Cummins Operation & Maintenance
manual is recommended for the engine. When followed, it will help with a longer
life, better performance and more cost efficient operations. A good maintenance
schedule begins with a daily awareness of the engine and its various systems.
The engine is equipped with an intake manifold grid heater. The grid heater
helps engine starting in cold weather. Intake manifold air temperature is moni-
tored by the Electronic Control Module on the engine. If intake manifold temper-
ature is below specified level (approximately 40º F.) manifold grid heater will be
activated. Grid heater activation is indicated by the WAIT TO START indicator
lamp.
WARNING: Use of ether starting fluids may cause an explosion
upon grid heater activation.
Chassis Information
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DIPLOMAT 10•283
ENGINE
- GENERAL
INFORMATION
ISC ENGINE
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