DIESEL CYCLE

This module contains the information about the diesel cycle,how it works and its efficency part in detail.Thiss will help you to enrich your information about diesel cycle .

1. Engineering Thermodynamics Diesel cycle Composed by:- Singh Roshan (Student)

2. Details Topic:- Diesel Cycle Branch:- Mechanical Department

3. Introduction to Diesel Cycle Diesel Cycle was derived by  Dr. Rudolph Diesel in 1893 , with an idea to attain a higher thermal efficiency, with a high compression ratio. This is an important cycle on which all the diesel engines work . It is also known as constant pressure cycle as heat is received at a constant pressure. The ideal diesel cycle consists of two reversible adiabatic or isentropic , a constant pressure and a constant volume processes . Diesel engines are used in aircrafts,automobiles,power generation,diesel electromotives, and both surface ships and submarines.

4. Classification of Diesel Engines Two Stroke Diesel Engine Four Stroke Diesel Engines

5. Working of Diesel Cycle Process 1-2:- Isentropic compression Process 2-3:-Constant Pressure (Isobaric)heat addition process Process 3-4:-Isentropic Expansion Process 4-1:-Constant Volume (Isochoric)heat rejection process

6. Diagram p-v Diagram T-S Diagram

7. Process 1-2 Isentropic Compression In this process,the piston moves from BDC to TDC and compression of air takes place isentropically.It means that during compression the entropy remains constant and there is no flow of heat out of the cylinder walls happens.Here the air is compressed so the process increases from P1 to P2,Volume decreases from V1 to V2,Temperature increases from T2 to T2 and entropy remains constant (i.e.s1=s2)

8. Process 2-3 Constant Pressure heat addition process:- I n this process the, the hot body is kept in contact with the cylinder and heat addition to the air takes place at constant pressure. During this process, the piston rest for a moment at TDC. The pressure remains constant (i.e. P2 = P3), volume increases from V2 to V3, temperature increases from T2 to T3, entropy increases from S2 to S3.

9. Process 3 -4 Isentropic Expansion In this process, after heat addition, the expansion of air takes place isentropically and work is obtained from the system. The piston moves downward during this process and reaches to BDC. The pressure falls from P3 to P4, Volume increases from V3 to V4, the temperature falls from T3 to T4 and entropy remains constant (i.e. S3=S4).

10. Process 4-1 Constant Volume heat rejection process:- In this process, the piston rest at BDC for a moment and the cold body is brought in contact with the cylinder and the heat rejection takes place at constant volume. The pressure decreases from P4 to P1, temperature decreases from T4 to T1, entropy decreases from S4 to S1 and volume remains constant (i.e.V4 = V1).

11. Thermal Efficency

12. DIESEL ENGINES: PROS & CONS Advantages Highly efficient Greater torque Durable Good resale value Disadvantages More expensive to purchase Fuel is pricey Less accessible Higher maintenance cost

13. Applications:- Diesel generators Locomotives Farming equipment In construction equipment In cargo and cruise ships In buses and trucks

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