There are two glands provided where the piston rod exits the cylinder shown in the illustration. The purpose of the top gland is to __________. Illustration MO-0083

Correct Answer: Option B — seal against scavenge air leakage

The top gland situated where the piston rod exits the cylinder in a two-stroke crosshead engine provides an effective pressure seal against high-pressure scavenge air. This prevents scavenge air from blowing down into the under-piston space or crankcase, ensuring optimal volumetric efficiency and maintaining proper scavenging dynamics.