COOLING SYSTEM
Altitude
As altitude increases air density decreases, and reduces engine and cooling system performance.
A 1°C per 305 m (2°F per 1000 ft) decrease in the ambient capability is assigned as a general rule.
The reduced atmospheric pressure will lower the boiling point of the coolant. A higher rated
pressure cap/relief valve may be required to suppress boiling.
Space Constraints
Cooling system design is often in
fl
uenced by space constraints. Heat exchanger height, width,
and depth can be dictated by the application. This, in turn, limits fan diameter and heat exchanger
surface area.
Noise Limits
Noise limitations are another environmental concern which can effect the cooling system.
Operating location and/or government regulations can limit noise generated by a cooling fan. Fan
noise is directly related to fan speed which affects air
fl
ow (refer to section 7.13).
Tilt Operations or Installations
Cooling systems
must
perform satisfactorily at maximum tilt operation. This is especially critical
for applications where the engine
must
operate for extended periods on steep grades.
7.10.4
SYSTEM COMPONENTS
Total heat rejected to the coolant and air must be determined to properly size the radiator ,
CAC, and fan arrangement so suf
fi
cient heat can be dissipated. This information is listed in the
“Technical Data” section of this manual (refer to section 14).
Additional Heat Loads to Coolant
The following items will add an additional heat load to the engine coolant:
□
Transmission coolers
□
Torque converters
□
Hydraulic oil coolers
□
Air compressors
□
Retarders
□
Brake coolers
□
Water cooled exhaust systems
□
Exhaust gas coolers
7-20
All information subject to change without notice.
(Rev. 03/06)
7SA250 0603
Copyright © 2006 DETROIT DIESEL CORPORATION
