Question

For two-stroke SI engine, the scavenging efficiency is 0.5, cylinder volume of 1200 cc and the scavenging density is 1.3 kg/m^3. What is the mass flow rate of air per cycle?

(a) 0.00072 kg/cycle

(b) 0.00076 kg/cycle

(c) 0.00074 kg/cycle

(d) 0.00084 kg/cycle

This question was posed to me in an interview.

The above asked question is from 2 Stroke Engines topic in portion Internal Combustion Engines of Automobile Engineering

Answer 1

The correct answer is (a) 0.00072 kg/cycle

The explanation is: Scavenging density = ρsc = 1.3 kg/m^3, total cylinder volume = Vtot = 1200cc, mass flow rate of air = ṁ a and the scavenging efficiency = ηsc = 0.5, ηsc = ṁa / (Vtot * ρsc) = ṁ a = Vtot * ρsc * ηsc = 0.0012 * 1.3 * 0.5 = 0.00072 kg/cycle.