In a two-stroke/cycle, opposed piston, diesel engine, one crankshaft operates several crank angles in advance of the other crankshaft to __________.

Correct Answer: Option A — allow the exhaust ports to open and close before the inlet ports close

Opposed-piston engines utilize crankshaft phasing lead to ensure exhaust ports open before intake ports for blowdown, and close after intake ports to maximize scavenging efficiency.