Exam Question
With reference to 2-Stroke Slow Speed Engine:
(a) Sketch and describe Main Engine Exhaust Valve. (8)
(b) List out a procedure for test of Main Engine Exhaust Valve after overhaul. (8)
Class 2 (2nd Engineer)
MEKM
📅 Jul 2024
Reference Answer
(a) Main Engine Exhaust Valve:
The valve body is made of cast iron, while the valve guide is made of polished steel. The valve seat is constructed from a nickel-based alloy and coated with Stellite to enhance wear resistance. The exhaust valve mechanism includes a hydraulic piston for opening the valve and an air piston to assist in valve closing.
The exhaust valve opens inward to the cylinder, utilizing the gas pressure to prevent carbon buildup on the valve seat and dislodge any contaminants. Cooling water from the cylinder head circulates through the exhaust valve to ensure proper cooling during operation.
Operation:
The valve body is made of cast iron, while the valve guide is made of polished steel. The valve seat is constructed from a nickel-based alloy and coated with Stellite to enhance wear resistance. The exhaust valve mechanism includes a hydraulic piston for opening the valve and an air piston to assist in valve closing.
The exhaust valve opens inward to the cylinder, utilizing the gas pressure to prevent carbon buildup on the valve seat and dislodge any contaminants. Cooling water from the cylinder head circulates through the exhaust valve to ensure proper cooling during operation.
Operation:
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