Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech IV Year AUTOMOBILE ENGINEERING Previous Question Paper (May/June - 2019 - R15)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Why lubrication is required for the automobile engines?
Answer
Lubrication is required in automobile engines primarily to reduce friction and wear between moving parts, such as the piston rings and cylinder walls, by creating a thin oil film that prevents metal-to-metal contact. Additionally, it serves to cool the engine by carrying heat away from internal components, cleans the engine by suspending contaminants and carbon deposits, and acts as a sealant to improve compression between the piston rings and cylinder.
What do you understand by the term injection timing in CI Engine?
Answer
Injection timing in a Compression Ignition (CI) engine refers to the precise moment, measured in degrees of crank angle before Top Dead Center (TDC), at which the fuel injection pump begins to deliver fuel into the combustion chamber. This timing is critical because it dictates the start of the ignition delay period and the subsequent combustion process.
Proper injection timing ensures that the fuel is injected when the compressed air temperature and pressure are at their peak, facilitating spontaneous ignition. If the timing is too early (advanced), it leads to excessive pressure rise and engine knocking due to a prolonged ignition delay. If the timing is too late (retarded), it results in incomplete combustion, reduced thermal efficiency, and increased exhaust smoke.
How does the horn and wiper work? Discuss.
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What is the spark advancing and retarding mechanism?
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Describe the function of clutch in the automobile.
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What is the significance of shock absorber for the automobile?
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Explain the principle of operation of mechanical braking system.
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What is the use of steering linkages in automobile engine?
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Explain the effect of automobile pollutants on the environment.
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Differentiate between Indian and International pollution standards.
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Part B
Differentiate between the functionality of mechanical fuel pump and electrical fuel pump used in the automobiles.
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What is the procedure adopted for the servicing of the engine in the automobile? Explain.
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Why the injection system is required in the diesel engine? Describe the requirements of better injection system.
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Explain the principle of operation of multiport fuel injection system used in the latest automobile engines.
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In electrical system of the automobile, what is the role of current voltage regulator and how does it function?
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What is different antifreeze solutions added along with the coolants of an automobile engine? Explain.
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Explain the constructional and operational principles of battery ignition system used in the automobile engine.
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Differentiate between evaporative cooling and pressure sealed cooling in automobile engines.
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Explain the significance of gear system in the automobile and describe the function of sychro mesh gear box.
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Describe the principle of operation of differential gear used in the rear axle of an automobile.
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What are the objectives of suspension system used in the automobiles? Explain different types of suspension systems.
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What do you understand by fluid flywheel and describe its significance.
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Describe the principle of operation of hydraulic braking system used in the automobile and discuss the limitations of hydraulic brakes.
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Differentiate among master cylinder, wheel cylinder and tandem master cylinder of hydraulic braking system.
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Draw the Ackerman steering mechanism used in automobile and explain the use of this steering system.
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Why the centre point steering system is better than other types of steering systems? Explain.
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How to use the Hydrogen as a fuel in the automobile? Explain the principle of operation of Hydrogen fuel engines.
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What are different pollution control techniques used to maintain the Indian pollution standards of automobiles? Explain.
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How to make use of Solar energy for the operation of automobile engine? Explain the principle of operation along with the circuit diagram.
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What are different alternate fuels used in automobiles? Explain their merits and demerits.
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