Diploma Thermal Engineering 1 Important Questions N Scheme three marks questions & answers – Unit – 3

Diploma Thermal Engineering 1 Important Questions

Join Diploma Exam Corner
Study Materials	Click here
Telegram Channel	Click here
YouTube	Click here

 

Dear Friends

We are adding Study Material for Diploma Thermal Engineering 1 Important Questions for the Unit 3 – 3 Marks. Check the link below to download diploma thermal engineering 1 important questions in pdf

Dept: Mechanical Engineering                                                     Scheme: N  

Subject: Thermal Engineering 1              

Unit – 3, Internal Combustion Engines

3 Marks 

1. Define I.C Engine

In I.C. Engine the combustion of fuel takes place inside the engine cylinder.

2. What are the important applications of IC Engine?

1. 1. IC engines are used in Road vehicles like scooters, motorcycles, buses etc.
   2. It is also used in Aircraft.
   3. IC engine is commonly used in Motorboats.
   4. IC engine has great application in small machines, such as lawnmowers, chainsaws, and portable engine-generators.

3. List the major parts of IC Engine.
4. Cylinder block
5. Cylinder head
6. Crank Case
7. Liner
8. Piston
9. Connecting rod
10. Crank shaft
11. Fly wheel
12. Piston rings &
13. Cam shaft

 

4. Compare S.I and C.I Engines

SI Engine	CI Engine
It is an engine in which the spark is used to burn the fuel.	It is an engine in which heat of compressed air is used to burn the fuel.
Petrol is used as fuel.	Diesel is used as fuel.
It operates on Otto cycle.	It operates on Diesel cycle.
Low compression ratio.	High compression ratio.
High thermal efficiency.	Less thermal efficiency.
Spark plug is used to produce spark for the ignition.	Heat of compressed air is used for the ignition.
High speed engines.	Low speed engines.

 

5. What is the function of Crank Shaft?

Crank shaft is the main rotating shaft in the engine. The oscillating motion of the connecting rod is converted into rotary motion by using Crank shaft

6. Write a note on Connecting rod

A connecting rod is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the crankshaft. The connecting rod is required to transmit the compressive and tensile forces from the piston.

7. What is piston?

Piston transmits the force of combustion to the crankshaft through connecting rod. It acts as a movable gas tight seal to keep the gases inside the cylinder under pressure.

8. Draw valve timing diagram for four stroke diesel engine

9. Draw the port diagram of two stroke cycle petrol engine

9. Draw the layout of fuel supply system in a petrol engine

9. What are the functions of piston rings in IC Engine?
   1. Piston rings prevents the leakage of gas into the crankcase
   2. It provides sufficient lubricating oil film
   3. Prevents the lubricant entry into the combustion chamber
10. List the advantages of air-cooling system

1. 1. Light in weight.
   2. No antifreeze is required.
   3. This system can be used where water scarcity is there.
   4. Simple in design.
   5. Require less space.

13. List the disadvantages of air cooling system

1. 1. More noise in operation.
   2. The coefficient of heat transfer of air is less, hence less efficient in working.

14. Mention the advantages of water cooling

1. 1. In these types of cooling, we see a high heat transfer rate.
   2. This type of cooling system is used where the size or power of the engine is more.
   3. Thermal Conductivity is more.
   4. Water is easily available.

15. Mention the disadvantages of Water cooling.
    • The system requires more maintenance.
    • The engine performance becomes sensitive to climatic conditions.
    • The power absorbed by the pump is considerable and affects the power output of the engine.
    • In the event of failure of the cooling system serious damage may be caused to the engine.

16. List out the properties of Lubricant.
    1. It should have suitable viscosity.
    2. It should act as protective covering against corrosion.
    3. It should have heavy strength to prevent metal to metal contact under heavy load.
    4. It should not react with the machine parts.
    5. It should have low pour point.

17. List out the types of Lubrication systems in I.C. Engine
    1. Mist Lubrication system or Petrol oil lubricating system
    2. Wet-sump Lubrication system
       • Splash Lubrication system
       • Pressure Lubrication system
    3. Dry sump lubrication system

18. What is Lubrication?

Lubrication is the process of reducing the friction between the two moving parts by supplying lubricating oil between the moving parts.

19. Define Governing

Governing is the process of keeping the engine speed in constant

20. What is the function of fuel filter?

The function of the fuel filter is to remove the foreign (dust) materials present in the fuel.

21. List the oil pumps used in lubrication systems.
    1. Gear pump
    2. Rotor pump
    3. Crescent type gear pump
    4. Rotor pump
    5. Vane pump
    6. Plunger pump
22. What is the function of the carburetor?

The function of the carburetor is to atomize the petrol and mix it with air in correct proportion

23. Mention the types of ignition systems in petrol engines
    1. Battery coil ignition system
    2. Magneto ignition system
    3. Electronic ignition system
24. What is scavenging?

Scavenging is the process of removing the waste burnt gases from the engine cylinder

25. What is MPFI?

MPFI Means Multi point fuel injection

26. What is CRDI?

CRDI Means Common Rail Direct Injection

Check N Scheme Mechanical Department Study Materials
Strength of Materials	Click here
Manufacturing Technology – 1	Click here
Thermal Engineering – 1	Click here
Metrology & Measurements	Click here

 

Join Diploma Exam Corner
Study Materials	Click here
Telegram Channel	Click here
YouTube	Click here