Mack M359, Руководство пользователя

Страница: 162 / 332

STARTING AND DRIVING
FUEL ECONOMY DRIVING
General
The absolute fuel consumption (counted
in liters per 100 kilometers or miles per
US gallon) is determined by a large
number of circumstances which can be
related to one of the following main
areas:
• Build specification and equipment
• Service and maintenance
• External environment
• Driving habits
Due to these factors, fuel consumption
can vary considerably within what is
called "normal fuel consumption." Fuel
consumption can vary from over 24
L/100 Km (10 mpg) when driving empty
on a nice and dry summer road to 67
L/100 Km (3.5 mpg) while driving with
maximum permitted GVW, with vehicle
and trailer, on a hilly and slushy winter
road.
Build Specification and
Equipment
Whenever a vehicle is used for
transportation, its build specification,
equipment and gross vehicle weight
have a decisive effect on both fuel
consumption and performance. The
factors which have the greatest
influence on fuel consumption are
primarily: driveline combination, height
of trailer or superstructure, use of air
fairings, tire type, number of wheels,
gross vehicle weight, and accessories.
Driveline Combination
Engine, transmission and final drive
must be selected in such a way that the
engine can operate within the economic
speed range at normal driving speed.
This range is defined as where the
engine makes the best use of the energy
content of the diesel fuel. A poorly
selected rear axle ratio, which results in
the engine speed being constantly
above the optimum speed, will increase
fuel consumption.
Tires
Heavy duty tires increase rolling
resistance considerably. For long haul,
choose a smoother, ribbed type tire.
Choose a lugged type tire only when the
added traction in mud and snow is
needed.
The number of wheels (axles) has a
direct effect on the rolling resistance
and, thereby, the fuel consumption. For
low volume and/or low weight
transports, use of a 4 x 2 instead of a 6
x 4 should be considered.
If the tire pressure is too low, the rolling
resistance increases and, thereby,
increases the fuel consumption. The
overall economy is also affected as tire
wear increases considerably.
Gross Vehicle Weight
The gross vehicle weight of a vehicle
combination has a large impact on the
rolling resistance.
Accessories
As a rule, accessories such as roof rack,
advertising signs, bug screens, exposed
air horns, etc., have a negative effect on
fuel consumption.
Service and Maintenance
A modern heavy-duty vehicle requires
regular and preventive maintenance to
ensure that all its components function
as they should. Use the recommended
preventive maintenance (PM) program
that has been developed for the
vehicles. This ensures optimal energy
efficiency from all components that are
important to fuel consumption.
152
X Publication_PC28