Volvo D11 series, Installation Manual

Page: 171 / 212

Engine room, ventilation and sound proofing
69
Engine power output and air temperature
The engine’s stated power output applies at an air
temperature of +25°C (+77°F), air pressure of 750
mm Hg, relative humidity 30%, fuel temperature
+40°C (+04°F) and seawater temperature of +32°C
(+90°F). (According to International test standards).
Adequate air supply and ventilation makes it possible
to obtain as high a power output as possible together
with a long engine life.
If the inlet air for the engine cannot be kept below
+25°C (+77°F), the
power output drops by up to
.5% for turbocharged engines and .0% for turbo-
charged engines with aftercooler for every +0°C
(+8°F) increase in air temperature. For normally as-
pirated engines, this figure can be up to 2%. In those
places in the world where the air temperature is con-
stantly at or above +45°C (+3°F), diesel engines
must be de-rated, i.e. the injection pump adjusted to
a lower injection quantity.
However, the driver can reduce the throttle
when op-
erating temporarily in such hot areas and thus avoid
these types of unfavourable operating conditions.
IMPORTANT! In those cases where operation
is at full throttle and the injection pump is not
adjusted (de-rated) despite high air tempera-
ture, the result will be very smoky exhaust, in-
creased thermal load and greatly increased en-
gine wear and consequently greatly increased
operating costs.
Engine power output at high altitudes
above sea level
In most cases, marine engines are run at or near sea
level. There are, however, some lakes that are situ-
ated at high altitudes above sea level.
There is loss of power when operating at high alti-
tudes due to the fact that the air density (and there-
fore oxygen content) decreases as altitude increases.
This results in smoky exhaust and the turbocharger
operating at abnormally high speeds with increased
wear.
The loss of power is, however, not important until ap-
prox 500 m (640 ft) above sea level.
At altitudes of more than 500 m (640 ft) above sea
level, there is a loss of power of approx 0.% per 00
m (328 ft).
De-rating should be done for high altitudes (reduced
fuel quantity) according to the following:
Altitude above sea Reduced fuel
level, metres (feet) quantity%
000 (3280) 4
500 (4920) 8
2000 (6560) 2
2500 (8200) 7
NOTE! De-rating is not possible on electronic control-
led engines!
NOTE! Electronic controlled engines are not suitable
for running at altitudes exceeding:
Rating 5 500 m (4920 ft)
Rating -4 2500 m (8200 ft)
NOTE! Emission certificates have not been verified
by Volvo Penta for altitudes above 500 m (4920 ft)