# ANNA UNIVERSITY QUESTION PAPAER

B.E. DEGREE EXAMINATION

IV Semester Automobile Engineering

AUTOMOTIVE PETROL ENGINES

Time : Three hours                                                                        Maximum : 100 marks

PART A — (10 ´ 2 = 20 marks)

1. List out eight important parts of 4 stroke petrol engine.

2. Write the firing order of four cylinder and six cylinder engine and its significance.

3. List out the functions of carburetion.

4. Sketch the cut–sectional view of Electrical Pump.

5. List four required properties of a good coolant.

6. What are the various types of lubrication systems?

7. Mention four important engine variables on Engine–knock.

8. Sketch four types of combustion chamber.

9. Name various types of two stroke engines.

10. List out various types of scavenging pumps.

PART B — (5 ´ 16 = 80 marks)

11. Compare by way of tabulation the differences between four stroke and two stroke engine.

12. (a)     Sketch and explain the working principle of carburettor involving starting,  idling and acceleration circuits.               (10)

Or

(b)     A petrol engine consumes 6.8 kg of petrol per hour. The specific gravity of the fuel 0.7 and its temperature 32°C. The air fuel ratio is 15. The choke tube has a diameter of 20 mm. Calculate the diameter of the single jet of the carburettor if the top of the jet is 5 mm above the petrol level in the float chamber. R of air can be assumed.                                (6)

13. (a)     (i)      Why we need a cooling system in Engines?                                     (6)

(ii)    Sketch and explain Mist lubrication system.                                (10)

Or

(b)     (i)      List the essential properties of lubricant used in vehicles.          (6)

(ii)    Explain with sketch the thermosyphen  cooling system.            (10)

14. (a)              Sketch and explain various stages of combustion in SI engines.

Or

(b)     (i)      Define the term knock and abnormal combustion.                         (6)

(ii)    List the factors controlling combustion chamber design.            (10)

15. (a)     Sketch and explain the working of any two types of two stroke engine.
(2 ´ 8 = 16)

Or

(b)     What are the various scavenging methods? (sketch and explain).

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