Search Result for "scavenging": 

The Collaborative International Dictionary of English v.0.48:

Scavenging \Scav"eng*ing\, p. pr. & vb. n. of Scavenge. Hence, n. (Internal-combustion Engines) Act or process of expelling the exhaust gases from the cylinder by some special means, as, in many four-cycle engines, by utilizing the momentum of the exhaust gases in a long exhaust pipe. [Webster 1913 Suppl.]