Automobile Engineering Multiple Choice Questions on “Flywheel”.
1. What is the maximum fluctuation of energy?
a) It is the sum of maximum and minimum energies
b) It is the ratio of the maximum and minimum energies
c) It is the ratio of the mean resisting torque to the work done per cycle
d) It is the difference between the maximum and minimum energies
Answer: d
Clarification: The maximum fluctuation of energy is the difference between the maximum and minimum energies. The fluctuation of energy can be found out by the turning moment diagram for one complete cycle of operation.
2. What is the coefficient of fluctuation of energy?
a) The ratio of the maximum fluctuation of energy to the minimum fluctuation of energy
b) The ratio of the maximum fluctuation of energy to the work done per cycle
c) The ratio of the minimum fluctuation of energy to the maximum fluctuation of energy
d) The ratio of the work done per cycle to the maximum fluctuation of energy
Answer: b
Clarification: The coefficient of fluctuation of energy (CE) is the ratio of the maximum fluctuation of energy to the work done per cycle. CE =(frac{Delta E}{T_{mean} theta}) where ΔE = maximum fluctuation of energy, Tmean*θ = work done per cycle, Tmean = mean torque, and θ = angle turned in radian in one cycle.
3. Which of the following is true about the flywheel?
a) Flywheel regulates speed over a period of time
b) Flywheel takes care of the quantity of fluid
c) Flywheel controls (frac{dN}{dt})
d) Flywheel regulates the speed by regulating the quantity of charge of the prime mover
Answer: c
Clarification: Flywheel controls the rate of fluctuation of the speed during a cycle. Flywheel controls the speed in one cycle. It does not control the supply of fuel to the engine.
4. Given that maximum fluctuation of energy is 2000 N-m/s and coefficient of fluctuation of speed is 0.02. What is the mean kinetic energy of flywheel?
a) 50 kN-m/s
b) 40 kN-m/s
c) 30 kN-m/s
d) 20 kN-m/s
Answer: a
Clarification: The maximum fluctuation of energy in a flywheel = ΔE, mean kinetic energy of the flywheel = E, and coefficient of fluctuation of speed = Cs. ΔE = 2*E*Cs ⇒ 2000 = 2*E*0.02 ⇒ E = 50 kN-m/s.
5. What is the coefficient of fluctuation of speed?
a) The ratio of the maximum fluctuation of speed to the mean speed
b) The ratio of the maximum fluctuation of energy to the mean speed
c) The ratio of the minimum fluctuation of energy to the mean speed
d) The ratio of the work done per cycle to the mean speed
Answer: a
Clarification: The coefficient of fluctuation of speed is the ratio of the maximum fluctuation of speed to the mean speed. Cs = (ω1 – ω2)/ω =2 (ω1 – ω2) / (ω1+ω2) or Cs = 2(N1-N2) / (N1+N2).
6. Which of the following is the expression of the maximum fluctuation of energy in a flywheel where I = mass moment of inertia of the flywheel, Cs = coefficient of fluctuation of speed, ω = mean angular speed of ω1 and ω2, and E = mean kinetic energy of the flywheel?
a) I*ω*(ω1+ω2)
b) I*ω*Cs
c) 2*E2*Cs
d) I*ω2*Cs
