Engine breathing in the two-stroke cycle is usually referred to as?

In the context of a two-stroke engine cycle, engine breathing is primarily related to the process known as scavenging. Scavenging refers to the method by which the exhaust gases are expelled from the combustion chamber and fresh air-fuel mixture is drawn in for the next cycle. This process is crucial because, in a two-stroke engine, both intake and exhaust occur almost simultaneously, and effective scavenging ensures that the combustion chamber is cleared of exhaust gases to make room for the incoming fresh charge.

This is typically achieved through the design of the engine ports and the use of the momentum of the exhaust gases as they exit, which helps create a low-pressure area that draws in the fresh mixture. Proper scavenging is vital for the efficiency and performance of a two-stroke engine since it directly impacts power output and emissions.

Understanding scavenging is key to grasping how two-stroke engines operate differently from four-stroke engines, where engine breathing occurs in a more sequential manner with designated intake and exhaust strokes.