Question

In __________ scavenging, the fresh air first sweeps across the piston top, moves up and then down finally out through the exhaust.

(a) loop

(b) uniflow

(c) cross

(d) none of the mentioned

The question was posed to me by my school principal while I was bunking the class.

Origin of the question is Scavenging Pumps in division Two Stroke Engines of IC Engine

Answer 1

Answer: (a) loop

Explanation:

In loop scavenging, the fresh air (or charge) enters the cylinder from ports located on the same side of the cylinder. It sweeps across the top of the piston, moves upward, and then down to expel the exhaust gases through exhaust ports located on the same side. This results in a loop-like movement of the charge within the cylinder.

• Uniflow scavenging involves the fresh charge entering from one end of the cylinder and moving in a single direction through the cylinder to exit from the exhaust port.
• Cross scavenging involves the intake and exhaust ports on opposite sides of the cylinder, causing a cross-flow of gases.

Thus, the correct answer is (a) loop.