(Table 21, contd)
(4)
The values of the fuel viscosity are the values as the fuel is delivered to the fuel injection pumps. Fuel should also meet the minimum viscosity
requirement and the fuel should meet the maximum viscosity requirements at 40° C (104° F) of either the "ASTM D445" test method or the
"ISO 3104" test method. If a fuel with a low viscosity is used, cooling of the fuel may be required to maintain 1.4 cSt or greater viscosity at the
fuel injection pump. Fuels with a high viscosity might require fuel heaters in order to lower the viscosity to 4.5 cSt at the fuel injection pump.
(5)
Follow the test conditions and procedures for gasoline (motor).
(6)
The lubricity of a fuel is a concern with low sulfur and ultra low sulfur fuel. To determine the lubricity of the fuel, use the “ISO 12156-1 or ASTM
D6079 High Frequency Reciprocating Rig (HFRR)” test. If the lubricity of a fuel does not meet the minimum requirements, consult your fuel
supplier. Do not treat the fuel without consulting the fuel supplier. Some additives are not compatible. These additives can cause problems in
the fuel system.
(7)
Recommended cleanliness level for fuel as dispensed into machine or engine fuel tank is "ISO 18/16/13 or cleaner as per ISO 4406. Refer to
the "Contamination Control Recommendations for Fuels" in this chapter.
NOTICE
Operating with fuels that do not meet the Perkins rec-
ommendations can cause the following effects: Start-
ing difficulty, poor combustion, deposits in the fuel
injectors, reduced service life of the fuel system, de-
posits in the combustion chamber and reduced serv-
ice life of the engine.
Engines that are manufactured by Perkins are certi-
fied with the fuel that is prescribed by the United
States Environmental Protection Agency. Engines
that are manufactured by Perkins are certified with
the fuel that is prescribed by the European Certifica-
tion and other regulatory agencies. Perkins does not
certify diesel engines on any other fuel.
Note: The owner and the operator of the engine has
the responsibility of using the fuel that is prescribed
by the Environmental Protection Agency (EPA) and
other appropriate regulatory agencies.
Diesel Fuel Characteristics
Perkins Recommendations
Cetane Number
Fuel that has a high cetane number will give a shorter
ignition delay. A high cetane number will produce a
better ignition quality. Cetane numbers are derived for
fuels against proportions of cetane and
heptamethylnonane in the standard CFR engine.
Refer to “ISO 5165” for the test method.
Cetane numbers in excess of 45 are normally
expected from current diesel fuel. However, a cetane
number of 40 may be experienced in some territories.
The United States of America is one of the territories
that can have a low cetane value. A minimum cetane
value of 40 is required during average starting
conditions. A higher cetane value may be required for
operations at high altitudes or in cold-weather
operations.
Fuel with a low cetane number can be the root cause
of problems during cold start.
Viscosity
Viscosity is the property of a liquid of offering
resistance to shear or flow. Viscosity decreases with
increasing temperature. This decrease in viscosity
follows a logarithmic relationship for normal fossil
fuel. The common reference is to kinematic viscosity.
Kinematic viscosity is the quotient of the dynamic
viscosity that is divided by the density. The
determination of kinematic viscosity is normally by
readings from gravity flow viscometers at standard
temperatures. Refer to “ISO 3104” for the test
method.
The viscosity of the fuel is significant because fuel
serves as a lubricant for the fuel system components.
Fuel must have sufficient viscosity in order to
lubricate the fuel system in both cold temperatures
and hot temperatures. If the kinematic viscosity of the
fuel is lower than 1.4 cSt at the fuel injection pump,
damage to the fuel injection pump can occur. This
damage can be excessive scuffing and seizure. Low
viscosity may lead to difficult hot restarting, stalling,
and loss of performance. High viscosity may result in
seizure of the pump.
Perkins recommends kinematic viscosities of 1.4 and
4.5 cSt that is delivered to the fuel injection pump. If a
fuel with a low viscosity is used, cooling of the fuel
may be required to maintain 1.4 cSt or greater
viscosity at the fuel injection pump. Fuels with a high
viscosity might require fuel heaters in order to lower
the viscosity to 4.5 cSt at the fuel injection pump.
Density
Density is the mass of the fuel per unit volume at a
specific temperature. This parameter has a direct
influence on engine performance and a direct
influence on emissions. This influence determines the
heat output from a given injected volume of fuel. This
parameter is quoted in the following kg/m at 15 °C
(59 °F).
Perkins recommends a value of density of 841 kg/m
in order to obtain the correct power output. Lighter
fuels are acceptable but these fuels will not produce
the rated power.
46 SEBU7833
Refill Capacities
Fluid Recommendations
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