Engine - General Information - Holiday Navigator 2003 Owner's Manual

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 piston 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
(turbocharger) 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 pressure 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
the 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 shutoff devices, to minimize risk of an
engine over-speeding where an engine (due to its application)
might operate in a combustible environment, such as fuel
spills or gas leaks. The equipment owner and operator is
responsible for safe operation of engine. Consult your engine
authorized repair location for future information.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
N A V I G A T O R 2 0 0 3
Chassis Information
ENGINE
- GENERAL
INFORMATION
1 0 • 4 1 7