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A.C.T. COLLEGE OF ENGINEERING AND TECHNOLOGY, NELVOY

DEPARTMENT OF MECHANICAL ENGINEERING

MODEL EXAMINATION - APRIL 2014

DEPT: MECHANICAL REGULATION: 2008

SUB.CODE & NAME: ME 2041- AIE YEAR & SEM: IV & VIII

DATE OF EXAM & SESSION: DURATION: 3.00 HRS

Part A (Answer all Questions) Marks (10 x 2 = 20)

1. Difference between engine and machine?

2. Mention the function of a carburetor?3. What do you mean by knocking?

4. Difference between CI and SI engine?

5. What are the mixture ratios available?

6. List down the disadvantages of HCCI engines?

7. What is a four valve engine? Why four valve engines is used in the modern day vehicles?

8. Give the composition of LPG and CNG?

9. List out some of the alternative fuels?

10. Give some advantages of natural gas?

Part B Marks (5 16 = 80)

11. (a) (i) Discuss the air fuel ratio requirements of an S.I.engine? (Marks 16)

(ii) Describe the various stages of combustion in a S.I engine with the help of a p-

diagram. Plot the heat release rate diagram also?

(or)

(b) (i) What action can be taken with regard to the following variables in order to reduce

the possibility of detonation in a S.I. engine? Justify your answers by reasons?

1) Compression ratio

2) Mass of charge induced

3)

Mixture inlet temperature

4) Distance of flame travel

(ii) Discuss the various factors that are to be considered in the design of SI engine

combustion chambers? (Marks 16)

12. (a) (i) Explain with the help of a p- diagram the various stages of combustion in a CI

engine?

(ii) Describe with a neat sketch the features of any one type of combustion chamber

employed in the modern day diesel engine? (Marks 16)

(or)

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(b) (i) Explain the principle of operation of a turbocharger with a neat sketch?

(ii) What do you understand by thermodynamics analysis? Explain. (Marks 16)

13. (a) (i) Explain the mechanism of formation of CO, UBHC and NOx in internalcombustion engines

(ii) Why three way catalytic converters are employed in the modern day S.I engine

driven vehicles? Show the plot of pollutants versus air fuel ratio and conversion

efficiency versus air fuel ratio for all the major pollutants from S.I engines.(Marks 16)

(or)

(b) (i) With the help of the neat sketch describe the principle of operation of FID analyser.

(ii) Draw the Indian driving cycle and explain the various stages. (Marks 16)

14. (a) (i) Explain any two techniques of using 100% alcohol in C.I engines indicating the

salient features.

(ii) Compare the important properties of natural gas with petrol. (Marks 16)

(or)

(b) (i) Describe the modifications required for using CNG in a CI engine.

(ii) List the advantages and disadvantages of using LPG in engines. (Marks 16)

15. (a) (i) What is a surface ignition engine? Explain its advantages and disadvantages.

(ii) With a neat sketch explain the operation of a stratified charge engine. (Marks 16)

(or)

(b) (i) Explain the characteristics of a common rail direct injection diesel engine.(ii) Discuss the method of obtaining pressure crank angle diagram. List down the

parameters that can be studied from the pressure crank angle diagram. (Marks 16)

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