University study material for Internal Combustion Engines in the Energy Engineering degree programme at Politecnico di Milano. The document covers: ADVANCED LC ENGINES UNIT -I MULTIPLE CHOICE QUESTIONS 1. The injection of fuel into a SI engine can be done by a) direct injection of fuel into the cylinder b) injection of fuel close to the inlet valve c) injection of fuel into the inlet manifold d) all of the mentioned 2.
University study material for Internal Combustion Engines in the Energy Engineering degree programme at Politecnico di Milano. The document covers: ADVANCED LC ENGINES UNIT -I MULTIPLE CHOICE QUESTIONS 1. The injection of fuel into a SI engine can be done by a) direct injection of fuel into the cylinder b) injection of fuel close to the inlet valve c) injection of fuel into the inlet manifold d) all of the mentioned 2.
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ADVANCED LC ENGINES UNIT -I MULTIPLE CHOICE QUESTIONS 1. The injection of fuel into a SI engine can be done by a) direct injection of fuel into the cylinder b) injection of fuel close to the inlet valve c) injection of fuel into the inlet manifold d) all of the mentioned 2. injection is adopted when manifold injection is contemplated. a) Continuous b) Timed c) All of the mentioned d) None of the mentioned 3.In injection, fuel is injected only during induction stroke over a limited period. a) continuous b) timed c) all of the mentioned d) none of the mentioned 4. Fuel injection in an SI engine volumetric efficiency. a) increases b) decreases c) maintains constant d) none of the mentioned 5. By using fuel injection in an SI engine, better efficiency is obtained. a) thermal b) mechanical c) unpredictable d) none of the mentioned 6. By using fuel injection in an SI engine, lower is obtained. a) exhaust emission b) thermal efficiency c) unpredictable d) none of the mentioned 7. The most accurate gasoline injection system is a) direct injection b) port injection c) throttle body injection d) manifold injection
8. Advantage of fuel injection in SI engine is a) low initial cost b) low maintenance requirements c) increased volumetric efficiency d) none of the mentioned 9. Detonation in SI engines occur due to a. Preignition ofthe charge before the spark b. Sudden ignition of the charge before the spark c. Autoignition of the charge after spark is struck d. None of the above 10. The theoretically correct air fuel ratio for petrol engine is of the order of a) 6:1 b) 9:1 el 1221 d) 15:1 11. The ignition of the charge by some hot surface within the engine before the passage of spark is called a) Pre-ignition b) Detonation c) Ignition delay d) Auto-ignition 12. Which of the following is the lightest and most volatile liquid fuel? a) Diesel b) Kerosene c) Fueloil d) Gasoline 13. The ignition quality of petrol is expressed by a) Cetane number b) Octane number c) Calorific value d) All of these 14. The maximum temperature in the I.C. engine cylinder is of the order of a) 500-1000°C b) 1000-1500°C c) 1500-2000°C d) 2000-2500°C
22. The minimum cranking speed in case of petrol engine is about a) Halfthe operating speed b) One fourth of operating speed c) 250-300 rpm d) 60-80 rpm 23. In petrol engines, advancing of the spark timing will______the knocking tendency. a) Noteffect b) Decrease c) Increase d) None of these 24. Stoichiometric ratio is a) Chemically correct air-fuel ratio by weight b) Chemically correct air-fuel ratio by volume c) Actual air-fuel ratio for maximum efficiency d) Noneofthe above 25. The process of breaking up or a liquid into fine droplets by spraying is called a) Vaporisation b) Carburetion c) Ionisation d) Atomisation 26. In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have a) Low density b) Low temperature c) Longignition delay d) All ofthese 27. The actual volume of fresh charge admitted in 4-stroke petrol engine is a) Equal to stroke volume b) Equal to stroke volume and clearance volume c) Less than stroke volume d) More than stroke volume 28. The power actually developed by the engine cylinder of an I.C. engine is known as a) Theoretical power b) Actual power c) Indicated power d) None ofthese
29. In a petrol engine, the fuel supplied to the engine cylinder is mixed with required quantity of air and the mixture is ignited with a a) Fuelpump b) Fuel injector c) Spark plug d) None ofthese 30. For maximum power generation, the air fuel ratio for a petrol engine for vehicles, is of the order of a) 9:1 b) 12:1 c) 15:1 d) 18:1 31. Which of the following statement is correct regarding petrol engines? a) Afine fuel spray mixed with air is ignited by the heat of compression which is ata high pressure b) The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug c) The fuel is first evaporated after passing through a carburettor and is mixed with air before ignition d) All of theabove 32. Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to a) Cylinder walls being too hot b) Overheated spark plug points c) Red hot carbon deposits on cylinder walls d) Any one of these 33. During idling, a petrol engine requires__ mixture. a) Lean b) Rich c) Chemically correct d) None of these 34. The air-fuel ratio in petrol engines is controlled by a) Controlling valve opening/closing b) Governing c) Injection d) Carburetion 35. By higher octane number of spark ignition fuel, it is meant that the fuel has a) Higher heating value b) Higher flash point c) Lower volatility d) Longerignition delay
44. 45. Advantage of fuel injection system in SI engine is a) Lowinitial cost b) Low maintenance requirements c) Increased volumetric efficiency d) None of the above Desirable characteristics of the combustion chamber for SI engines to avoid knock is a) Small bore b) Short ratio of flame path to bore c) Absence of hot surface in the last region of the charge d) All of the above ANSWER KEY 1 2 3 4 5 6 7 8 9 10 D A B A A A B c c D 11 12 13 14 15 16 17 18 19 20 A D B D A c B A A D 21 22 23 24 25 26 27 28 29 30 c D c B D D c c c B 31 32 33 34 35 36 37 38 39 40 B D B D D A A A A c 41 42 43 44 45 D A B c D
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