In a two-stroke marine diesel engine, what does scavenging mean?

Prepare for the Engineman EN A School Test 1. Utilize flashcards and multiple choice questions with detailed explanations to boost confidence and readiness for the test.

Scavenging is the process of clearing exhaust gas from the cylinder and filling it with air and a fresh charge for the next cycle. In a two-stroke marine diesel, as the piston moves and exhaust ports open, the remaining exhaust is pushed out by incoming scavenging air. That same flow then fills the cylinder with fresh air (and fuel is added later in the cycle), preparing the chamber for the next combustion event. The effectiveness of scavenging is key: it removes used gas and avoids losing the fresh charge straight out the exhaust, ensuring there’s enough oxygen for efficient combustion. The other ideas focus only on cooling, ignition, or just expelling exhaust, but scavenging combines removing exhaust with introducing a fresh charge for the next cycle.