MT 313 IC ENGINES LECTURE NO: 03 (19 Feb, 2014) Khurram Yahoo Group Address: ICE14
QUESTIONS What is the advantages and Disadvantages of four stock engines? What is the advantages and Disadvantages of two stock engines? What is the advantages and Disadvantages of Petrol engines? What is the advantages and Disadvantages of Diesel engines? What is the advantages and Disadvantages of Wankel stock engines? Compare 4 - stroke & 2 - stroke Engine?
QUESTIONS Describe working principles of Wankel engines? Numerate performance parameters of the I.C. engines?
Ideal cycles are simplified
Ideal Cycles More realistic than Carnot cycle. Internally reversible but not totally. Idealizations: – No friction – Expansions and compressions – quasi-equilibrium – Heat transfer is negligible
Different Processes IsobaricIsometric Adiabatic ΔT ≠ 0 but Q = 0 Isothermal ΔT = 0 but Q ≠ 0 Cyclic If clockwise – heat engine If counterclockwise – heat pump
Area inside the cycle represents net work out for TS or PV diagrams.
Otto Cycle, ideal for spark ignition engines
TS plot of the Otto Cycle
Efficiency vs Compression Ratio Higher ratios produce autoignition and knocking
Efficiency vs ratio of specific heats Air Combustion mixture He
The Ideal Otto Cycle