Volvo Engine System Design - Cooling System,Induction System
by Starlight Generator dieselgeneratortechSummary of System Design for
Volvo engine
The following points must be
given extra thorough consideration when designing a cooling system:
• The maximum
ambient temperature the engine must operate in.
• Cooling air
flow direction, i.e. if a puller or pusher fan is to be used. A pusher fan is
recommended for generator sets to avoid generator overheating. On mobile applications,
consideration must be give to any slipstream.
• Engine heat
radiation causes a rise in cooling air temperature in pusher fan systems.
• Generator
heat contribution is 7-10 % of net engine power.
• Additional
coolers in front of the radiator (puller fan) or behind the radiator (pusher
fan) will cause a rise in cooling air temperature and a reduction in airflow.
• The
radiator may become clogged in dusty environments, which will impair cooling
capacity.
The radiator must be installed so
that it can easily be cleaned. Grilles / filters are available as options.
• There must
be as few obstacles to cooling air flow as possible. The design of air ducts,
grille and engine compartment is important.
• Hot air
recirculation will impair cooling capacity significantly and must be prevented
by sealing.
• Where
accessory components such as a torque converter oil cooler are connected to the
coolant system, it is necessary to know the cooling requirement for such
components.
•
Consideration must be given to the altitude above sea level at the location
where the engine will be used, as ATB is reduced by around 1.4 °C (34.5 °F) at
300 m (984 ft.)
• If it is
necessary to increase cooling capacity, it must be done in the first instance
by using a larger radiator and improving cooling air flow.
Important to
bear in mind regarding the coolant circuit
• Coolant
flow and external circuit sensitivity to pressure drop. One extremely critical
parameter when designing a cooling system is coolant flow. The pressure in the
coolant system, which the pump works against, is linear to the amount of
coolant that must circulate. When the thermostat opens back pressure increases
and flow drops. Therefore, do not increase the external coolant system beyond
the permissible maximum volumes specified in the technical data for each
individual engine.
Also refer to technical
data/cooling system
• Cooling
effect and maximum cooling temperature. Refer to technical data/cooling system“heat rejection from engine” and “Maximum top
tank temperature”
• Static main
pressure. Refer to technical data/cooling system“maximum static
main pressure” and “minimum static main pressure”
• Expansion
tank volume. The total amount of coolant used in the system affects the
appropriate size of the expansion tank. Minimum expansion tank size is 18 % of
the total coolant volume.
Refer to the expansion tank chapter
• Venting.
Refer to the venting, nipples,
pipes and hoses chapter
• Pipe and
hose quality Refer to the radiator, pipes and hoses chapter.
Important to
bear in mind regarding the charge air circuit
• Charge air
temperature and cooling capacity. Engine charge air temperature should be as
low as possible. This is beneficial for fuel consumption and increases total
engine service life. (lower stress effects from heat at maximum load points).
Therefore pay attention to the need for effective cooling.
• Pressure
drop across the charge air system. Refer to technical data/cooling
system/charge air system
• Load
take-up. Be aware that the increase in air volume created by extending the
charge air pipes will have a drastically negative effect on load take-up.
• Pipe runs
and installation (clamps). Refer to the charge air cooler chapter
Induction System
General
The air inlet system is one of
the most important parts of the engine installation as it is able to directly
affect engine power, fuel consumption, exhaust emissions and engine service
life. Bearing this in mind the air inlet system must be designed so that it is
able to provide the engine with clean, dry, cold air with the smallest possible
flow limitation. The system must also be designed to cope with the shock loads
and operating conditions that occur during use. It must also provide reliable
sealing and durability.
Air Inlet System
The air inlet system consists of
three main components:
- Air inlet - before filter
- Air cleaner
- Air inlet - after filter
Inlet pipe,
before filter
The air inlet must be installed
in a location
- that has the lowest possible
dust concentration
- where the temperature is as
close to ambient air temperature as possible
- and which is protected from
water splashes
The inlet must be protected
against rain and snow. Make sure it is not possible for exhaust gases to be
drawn in to the air inlet system. The air inlet pipe must be designed so that
pressure drop is minimized. A small pressure drop extends filter service life.
The basic guidelines for achieving a low pressure drop involve using large
pipes with as few short-radius bends as possible. A water lock must be designed
in the lower section of the pipe and/or where it bends upwards. The water lock
must be drainable. The filter housing must also be drainable. Installation,
Induction System
Cleaner Type
Air cleaner
Air cleaners protect engines
against airborne contaminants that cause serious engine wear through their
abrasive effect. Air cleaners can be divided into three basic types:
- pre-cleaner
- primary cleaner
- secondary element
Pre-cleaner
The function of the pre-cleaner
is to remove the major part of airborne dirt from inlet air and to extend
primary element service life. Pre-cleaners work by forcing air to rotate thus
separating the dust from the air. There are two main types of pre-cleaner:
- multi-cyclone filters installed
in the air inlet
- stators installed in the filter
housing
Volvo Penta recommends the use of
pre-cleaners in dusty environments.
Primary
cleaner
Primary cleaners can be divided
into two types:
- oil bath type
- paper type
Paper type primary cleaners can
be divided into:
- dry type
- oil-treated type
The cleaning efficiency of oil
bath type cleaners is usually 70-90 %.
Dry type cleaning efficiency is
95-99.8 %.
Oil-treated type cleaning
efficiency is 95-98 %.
Oil bath
type
Air filters of the oil bath type
must be accurately adapted to engine type and operating speed for them to work
correctly. If the filter is not adapted to the engine, filtration may be poor
and/or the oil can be transferred from the filter to the engine. Oil bath
filters also have a limit regarding incline, i.e. the angle at which the
installation may slope before oil begins to be transferred to the engine. For
this reason Volvo Penta recommends that oil bath filters not be used.
Dry paper
type
Filtration in a dry filter
improves during filter service life. The filter is at its most effective when
the pressure drop indicator indicates that the filter must be changed.
IMPORTANT!
Dry filters may never be cleaned
with compressed air, washed in fluids or knocked against the floor to empty out
dirt. If dry filters are cleaned small leaks occur that cannot be seen with the
naked eye. There is also a risk of dust being transferred to the clean side
while the filter is removed.
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Created on Aug 2nd 2018 01:53. Viewed 601 times.