Volvo D11 series, Installation Manual

Page: 173 / 212

Engine room, ventilation and sound proofing
7
The ambient air temperature (outdoor air tempera-
ture) is assumed to be +30
°C (86°F). Correction fac-
tors as per Table 2 shall be used where applicable.
Ambient air temperature Correction
°C (°F) factor
+20 (+68) 0.7
+30 (+86) .0
+40 (+04) .4
Table 2.
Fan selection
The fan must be dimensioned for air flow volume ac-
cording to the following:
Flow m³ / min = 0.07 × engine power output in kW.
This volume flow is corrected by a factor from the
table.
The total pressure increase through the fan should
be 0 mm (0.394") wat.col. (00 pa).
These two values, flow and total pressure increase,
are sufficient for the selection of a fan. If the fan is fit-
ted directly to the bulkhead, i. e. without a connection
pipe, the value of the total pressure increase can be
reduced to 7 mm (0.276") w.col. (70 pa). This means
that a somewhat smaller fan can be used.
Engine’s air consumption
The engine consumes a certain amount of air in the
combustion process. This requires a minimum inter-
nal area of air supply ducting. The area can be calcu-
lated by using the formula:
A = .9 × engine power output
A = Area in cm²
Engine output in kW
The value applies for non-restricted intake and up to
m (3.3 ft) duct length with only one 90 degree bend.
The bending radius should be at least twice the dia.
If longer ducts or more bends are used, the area is
corrected by multiplying by a coefficient from
Table 1
below.
Number Metres (ft) duct length
of bends (3.3) 2 (6.6) 3 (9.8) 4 (3.) 5 (6.4)
.04 .09 .3 .20
2 .39 .4 .43 .45 .49
3 – .70 .72 .74 .78
Table .
Engine room ventilation
To keep the engine room temperature down to the
permitted values, a great deal of the radiant heat
must be transported out of the engine room, in other
words be ventilated away.
The same dimension must be chosen for the inlet
and outlet ducts to achieve low flow speeds and low
noise levels.
The area for the inlet/outlet air supply is calculated
using the formula:
Inlet air = .65 × engine power output
Outlet air = .65 × engine power output
Areas in cm² and engine power output in kW.
These values must be corrected according to
Table 1
with regard to bends and duct length.