A loop or cross scavenged engine utilizes the motion of its pistons and a turbocharger to provide scavenging air. Which of the listed mechanical designs prevents the air under the pistons from being pumped back through the scavenge ports during the piston power stroke?

Question

Accepted Answer

Option A: Length of the piston skirt. The extended length of the piston skirt physically blocks the intake ports during the initial phase of the power stroke, preventing lower crankcase or under-piston scavenge air from blowing backward.