Perkins 1103D Series, Руководство по эксплуатации и обслуживанию, Страница: 32 / 78

The Water Temperature Regulator and
Insulated Heater Lines
The engine is equipped with a water temperature
regulator. When the engine coolant is below the
correct operating temperature, jacket water circulates
through the engine cylinder block and into the engine
cylinder head. The coolant then returns to the
cylinder block via an internal passage that bypasses
the valve of the coolant temperature regulator. This
system ensures that coolant flows around the engine
under cold operating conditions. The water
temperature regulator begins to open when the
engine jacket water has reached the correct
minimum operating temperature. As the jacket water
coolant temperature rises above the minimum
operating temperature the water temperature
regulator opens further allowing more coolant
through the radiator to dissipate excess heat.
The progressive opening of the water temperature
regulator operates the progressive closing of the
bypass passage between the cylinder block and
head. This system ensures maximum coolant flow to
the radiator in order to achieve maximum heat
dissipation.
Note: Perkins discourages the use of all air flow
restriction devices such as radiator shutters.
Restriction of the air flow can result in the following:
high exhaust temperatures, power loss, excessive
fan usage and reduction in fuel economy.
A cab heater is beneficial in very cold weather. The
feed from the engine and the return lines from the
cab should be insulated in order to reduce heat loss
to the outside air.
Insulating the Air Inlet and Engine
Compartment
When temperatures below −18 °C (−0 °F) will be
frequently encountered, an air cleaner inlet that is
located in the engine compartment may be specified.
An air cleaner that is located in the engine
compartment may also minimize the entry of snow
into the air cleaner. Also, heat that is rejected by the
engine helps to warm the intake air.
Additional heat can be retained around the engine by
insulating the engine compartment.
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Fuel and the Effect from Cold
Weather
Note: Only use grades of fuel that are recommended
by Perkins. Refer to this Operation and Maintenance
Manual, “Fluid Recommendations”.
Properties of the diesel fuel can have a significant
effect on the engine cold start capability. Critical to
the low temperature properties of diesel fuel is the
acceptability for the minimum ambient temperature
the engine is expected to see in operation. Following
properties are used to define fuels low temperature
capability:
• Cloud point
• Pour point
• Cold Filter Plugging Point (CFPP)
The cloud point of the fuel is the temperature at
which waxes naturally found in diesel fuel begins to
form crystals. The cloud point of the fuel must be
below lowest ambient temperature to prevent filters
from plugging.
CFPP is a temperature at which a particular fuel will
pass through a standardized filtration device. The
CFPP gives an estimate of the lower operability
temperature of fuel.
Pour point is the last temperature before the fuel flow
stops and waxing of the fuel will start.
Be aware of these properties when diesel fuel is
purchased. Consider the average ambient air
temperature for the engines application. Engines that
are fueled in one climate may not operate well if the
engines are shipped to colder climate. Problems can
result due to changes in temperature.
Before troubleshooting for low power or for poor
performance in the winter, check the fuel for waxing.
The following components can provide a means of
minimizing fuel waxing problems in cold weather:
• Fuel heaters, which may be an OEM option
• Fuel line insulation, which may be an OEM option
Winter and arctic grades of diesel fuel are available in
the countries and territories with severe winters. For
more information refer to the Operation and
Maintenance Manual, “Cold Weather Operation”
Another important fuel property which can affect cold
start and operation of diesel engine is cetane
number. For more information refer to the Operation
and Maintenance Manual, “Fluid Recommendations”.
32 SEBU8352-02
Operation Section
Fuel and the Effect from Cold Weather