Engine Air Consumption; Engine Room Ventilation - Hyundai u125 series Installation & Operation Manual

1. ENGINE AIR CONSUMPTION

-. The engine needs to have a proper volume of intake air for combustion. This requires a
minimum internal area of air supply ducting the area can be calculated by using the following
formula:
A = cross section of area in cm2
A = 1.9 X Engine power (KW)
A= 1.9 X 93 (KW) = 176.7cm
Area = π r2. (176.7 / π (3.14) = 56.27
Square Root of 56.27 = 7.5 = radius. 2 x radius = diameter (15)
Minimum intake area is Ø15cm. When use longer ducts or more bends are used the area
is corrected by multiplying by coefficient from the table above. We recommend to position
the air inlet around 25~35cm from the air filter. The air inlet must never be installed in the
transom as water and/or exhaust gases could be ingested.
Example) Length of pipe : 3M , number of pipe bands : 2
 Ø15cm X 1.43 = Ø21.45cm
※ Minimum Bending Radius = 2 X O.D of pipe (90° case)

2. ENGINE ROOM VENTILATION

-. Engine room needs proper ventilation for optimum engine operation. This requires a
minimum internal area of air ventilation. The area can be calculated by using the formula:
A = 1.65 X Engine power (KW)
 A= 1.65 X 93 (KW) = 153.45cm
-. Minimum ventilation area is Ø13.98cm, when using longer ducts or more bends are used the
area is corrected by multiplying by coefficient from the table above. The air inlet and outlet
vents should be the same size. The distance between air inlets and air outlets should be as
far as possible from each other. If the distance is too short, air will not circulate properly
which will result in bad ventilation. A blower should be installed in the exhaust air duct to
ventilate and cool the engine room more effectively.
Extraction fan capacity (Air Flow m3/min) =0.07 X Engine power (KW)
Extraction fan capacity = 0.07 X 93 (KW) = 6.51m
※ General pressure drop of Engine room = 0.1~0.5kPa
Example) Length of pipe : 3M , number of pipe bands : 2
 Ø13.98cm X 1.43 = Ø19.99cm
INSTALLATION & OPERATION MANUAL
U125 Series Engines
CHAPTER 5
AIR INTAKE SYSTEM
= Ø 15cm
2
= Ø13.98cm
2
Number of
pipe bends
1
(90°)
1 1
2 1.39
3 -
/min
3
-31-
Length of pipe (Meters)
2 3 4
1.04 1.09 1.13 1.20
1.41 1.43 1.45 1.49
1.70 1.72 1.74 1.78
5