1. THERMODYNAMIC ANALYSIS OF IC ENGINE Prepared by- Sudeesh kumar patel

2. INTRODUCTION An engine which generates motive power by the burning of petrol, oil, or other fuel with air inside the engine, the hot gases produced being used to drive a piston or do other work as they expand. Internal-combustion engine-

3. CLASSIFICATION OF INTERNAL- COMBUSTION ENGINE-

4. Process 1→ 2 Isentropic compression Process 2 → 3 Constant volume heat addition Process 3 → 4 Isentropic expansion Process 4 → 1 Constant volume heat rejection v 2 TC v 1 BC Q out Q in Air-Standard Otto cycle Compression ratio:

5. First Law Analysis of Otto Cycle 1→2 Isentropic Compression AIR 2→3 Constant Volume Heat Addition AIR Q in TC

6. 3 → 4 Isentropic Expansion AIR 4 → 1 Constant Volume Heat Removal AIR Q out BC

7. Cycle thermal efficiency: Indicated mean effective pressure is : Net cycle work: First Law Analysis Parameters

8. Effect of Compression Ratio on Thermal Efficiency Effect of Specific Heat Ratio on Thermal Efficiency

9. Process 1→ 2 Isentropic compression Process 2 → 3 Constant pressure heat addition Process 3 → 4 Isentropic expansion Process 4 → 1 Constant volume heat rejection Air-Standard Diesel cycle Q in Q out Cut-off ratio: v 2 TC v 1 BC TC BC

10. For cold air-standard the above reduces to: Thermal Efficiency, Note the term in the square bracket is always larger than one so for the same compression ratio, r, the Diesel cycle has a lower thermal efficiency than the Otto cycle Note: CI needs higher r compared to SI to ignite fuel

11. Typical CI Engines 15 < r < 20 When r c (= v 3 /v 2 )→1 the Diesel cycle efficiency approaches the efficiency of the Otto cycle Thermal Efficiency Higher efficiency is obtained by adding less heat per cycle, Q in, → run engine at higher speed to get the same power.

12. For the same inlet conditions P 1, V 1 and the same compression ratio P 2 /P 1 : For the same inlet conditions P 1, V 1 and the same peak pressure P 3 : Diesel Dual Otto Diesel Dual Otto “x” →“2.5” P max T ma x PoPo PoPo Pressure, P Temperature, T Specific Volume Entropy

13. HEAT DISTRIBUTION IN INTERNAL COMBUSTION ENGINE

14. CONTACTS- ✕ Sudeesh kumar patel- Sudeesh.patel781@gmail.com