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| Illustration 1 | g00745617 |
Typical arrangement of ventilation for the engine room (1) Noise absorbing chambers with deflector baffles (2) Noise absorbent panels | |
The engine room must be ventilated in order to supply the engine with combustion air. The engine room must also be ventilated in order to provide flow of air around the engine. Flow of air is needed so that certain engine components will not overheat.
Most applications will draw air from the engine room. The engine requires a vent area of 6.35 mm2 (0.250 in2) for every horsepower that is produced. In hot climates, the engine requires 12.7 mm2 (0.50 in2) of vent area. Refer to Table 1 for the minimum cross section of air duct per engine.
| Minimum Cross Section of Air Duct Per Engine | ||
| Engine | Hot Climates | Normal Climates |
| Naturally aspirated 3034 Marine engine | 210 cm2 (32 inch2) |
110 cm2 (16 inch2) |
| Turbocharged 3034 Marine engine | 260 cm2 (40.3 inch2) |
130 cm2 (20 inch2) |
Note: The ambient air that enters the engine should not exceed 52 °C (125 °F).
Forward facing vents should allow the flow of air through the engine room. Vents should be installed in order to allow hot air to exit the engine room. An effective engine room allows no more than a 9 °C (15 °F) higher temperature than the ambient air temperature. The vents should be positioned so that the water spray is not allowed to enter the engine room. Some form of water trap is also preferable.
When the engines are shut down after an extended run, the temperature of the engine room will rise. In vessels with an open wheel house, there should be no problem. If the engine is installed below the wheel house, warm conditions may result. In this instance, ventilation in the engine room would be beneficial. The ventilation should allow air to flow over the engine.