Question

Scavenging process consists of __________

(a) pre-blowdown stages

(b) blowdown

(c) scavenging

(d) all of the mentioned

I have been asked this question in an online quiz.

Question is taken from Scavenging Pumps topic in division Two Stroke Engines of IC Engine

Answer 1

Answer: (d) all of the mentioned

Explanation:

The scavenging process in two-stroke engines consists of three stages:

1. Pre-blowdown stages: This refers to the period before the exhaust valve or port opens. In this phase, the pressure in the cylinder is still high, and the combustion gases are being prepared for expulsion.

2. Blowdown: This is the phase where the exhaust gases are expelled from the cylinder as the exhaust port opens. The pressure inside the cylinder is higher than that in the exhaust system, allowing the gases to exit.

3. Scavenging: After the exhaust gases are expelled, fresh air (or fuel mixture in petrol engines) is introduced into the cylinder to flush out any remaining exhaust gases, preparing the cylinder for the next combustion cycle.

Thus, all these stages together make up the scavenging process in two-stroke engines. The correct answer is (d) all of the mentioned.