Cylinder scavenging is best described as

• A. Refers to the flow of fuel air mixture into a diesel engine.
• B. Refers to the removal of exhaust gases from the cylinder
• C. May be aided with air injectors to rapidly fill the cylinder
• D. Is performed by a special piston ring that removes excessive oil from the cylinder walls

Answer: (B)

Cylinder scavenging is the process of clearing the cylinder of exhaust gases to make room for the next fresh charge. This clearing is essential so that the incoming air-fuel mixture can ignite cleanly and produce efficient combustion; without proper scavenging, spent gases remain and dilute or dilute the next charge, reducing power and increasing emissions. In many engines, especially two-stroke designs, the incoming fresh mixture helps push the exhaust out as it enters, which is why scavenging is all about removing exhaust from the cylinder.

The other ideas mix in with different functions: the flow of fuel-air mixture into the cylinder describes induction, not scavenging. The notion of using air injectors to rapidly fill the cylinder isn’t the standard description of scavenging. And a special piston ring that removes excess oil from the cylinder walls is related to oil control, not scavenging.