78 + Interview Questions in Petrol Engine Fuel Supply System in Automotive Engine Design Page 2 InterviewSolution

51.	Which of the following is provided in the float chamber to keep the pressure inside atmospheric?(a) Float(b) Fuel jet(c) Small vent(d) Throttle valveThe question was asked in an interview for job.Origin of the question is Petrol Engine Fuel Supply System in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct choice is (c) Small vent For EXPLANATION I would say: A small vent in the float chamber keeps the PRESSURE INSIDE the ATMOSPHERIC. In modern practice, it is preferred to vent the float chamber to the air INTAKE of the carburetor. In modern practice, it is preferred to vent the float chamber to the air intake of the carburetor.

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52.	Which of the following material is used to make the float of a carburetor?(a) Paper(b) Sheet metal(c) Nylon plastic(d) Cast ironI had been asked this question during a job interview.Origin of the question is Petrol Engine Fuel Supply System in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» CORRECT OPTION is (b) Sheet metal Explanation: The floats have a tendency to leak along the joint seams.due to which they are made of nylon plastic or expanded SYNTHETIC rubber. The NEEDLE valve ATTACHED to the float serves to close or open the fuel inlet to the float chamber depending on the requirements.

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53.	Which among the following is used to mesh with the cleaning material in a light-duty type of air filter?(a) Mesh screen(b) Plastic(c) Polymer coating(d) Sheet metalThe question was posed to me in homework.The origin of the question is Petrol Engine Fuel Supply System in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right choice is (a) Mesh screen The best EXPLANATION: The air cleaner CONSISTS of a cylindrical cellulose fiber MATERIAL, over which is put a fine mesh screen to PROVIDE strength. The element is corrugated to increase the surface area exposed to the incoming air so that the resistance offered by the cleaner reduced to a minimum.

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54.	Which are the parts that get damaged when dirt enters the crankcase?(a) Heavy-duty type air cleaner(b) Light duty type air cleaner(c) Thermostatic control of air cleaner(d) Heavy-duty type air cleaner and Light duty type air cleanerThis question was posed to me during a job interview.This intriguing question comes from Petrol Engine Fuel Supply System in section Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» CORRECT choice is (d) Heavy-DUTY type air cleaner and Light duty type air cleaner The best I can explain: If the dirty air enters the CRANKCASE, it will contaminate the lubricating oil and ultimately damage the bearings and JOURNALS and decrease the SERVICE period of the lubrication system.

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55.	Which among the following is the correct air movement in a heavy-duty type air cleaner?(a) Inlet – circumferential gap – oil bath – filter(b) Inlet – filter – oil both – the circumferential gap(c) Inlet -oil bath – filter – the circumferential gap(d) Circumferential gap- inlet -oil bath – filterThis question was posed to me during an interview.Query is from Petrol Engine Fuel Supply System in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct choice is (a) Inlet – circumferential gap – oil bath – filter The best I can EXPLAIN: The flow of AIR starts through the inlet and passes through the circumferential gap where the airflow TAKES a turn and then the oil bath and the filter which is dipped in oil where the total IMPURITIES present in the air are removed.

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56.	In which type of air cleaner the filter element is saturated with oil?(a) thermostatic control of air cleaner(b) light dusty type air cleaner(c) heavy-duty type air cleaner(d) both thermostatic and light dusty typeI got this question during an online exam.My doubt stems from Petrol Engine Fuel Supply System topic in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct answer is (c) heavy-duty type AIR cleaner For explanation: The heavy-duty type air cleaner is also called an oil bath type wherein the filter material is saturated with oil. IMPINGING on the SURFACE of the oil RELIEVES the air further of the impurities. The final cleaning is done by a filter and clean air is passed to the ENGINE.

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57.	To increase which of the following the cleaning element is corrugated and exposed to the incoming air?(a) Temperature(b) Pressure(c) Surface area(d) ForceI got this question in semester exam.Origin of the question is Petrol Engine Fuel Supply System topic in section Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right choice is (c) SURFACE area Best explanation: The element is corrugated to increase the surface area exposed to the incoming air so that the resistance OFFERED by the CLEANER is REDUCED to a minimum. Sides of the element are sealed against dust. The air passes through the element and any dust contained is left outside.

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58.	Which material is used as a cleaning element in a light-duty type air cleaner?(a) Plastic(b) Metal(c) Cellulose(d) Both Plastic and metalThis question was posed to me in an online quiz.This key question is from Petrol Engine Fuel Supply System in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The correct answer is (c) Cellulose For explanation: The cleaning ELEMENT consists of a cylindrical cellulose fiber material, over which is PUT a fine mesh SCREEN to provide strength. The element is corrugated to increase the surface AREA exposed to the INCOMING air.

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59.	At what temperature in degree centigrade such that the bleed valve opening is maximum when the hot air supply is cut-off?(a) 10(b) 20(c) 30(d) 40I had been asked this question in examination.My query is from Petrol Engine Fuel Supply System topic in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The correct ANSWER is (d) 40 Easy explanation: At 40-degree CENTIGRADE, the bleed valve OPENING is MAXIMUM when the hot air supply is cutoff and only outside air enters the carburetor. This is provided in modern ENGINES to reduce air pollution.

Discussion

60.	In which type of air filter at idling or cold start condition the incoming air is heated and then sent to the cleaner?(a) Heavy-duty type air cleaner(b) Light duty type air cleaner(c) Thermostatic control of air cleaner(d) Heavy-duty type air cleaner and Light duty type air cleanerThis question was addressed to me in an online quiz.My question is taken from Petrol Engine Fuel Supply System in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right option is (c) Thermostatic control of air cleaner The BEST explanation: In the modern engine the lean fuel-air is USED to REDUCE the pollution due to which efficiency decreases, therefore, to REMEDY this the incoming air is HEATED and then sent to the air cleaner.

Discussion

61.	Which among the following is an example ofan oil bath type air filter?(a) Thermostatic control of air cleaner(b) Light duty types of air cleaner(c) Heavy-duty type air cleaner(d) Thermostatic control of air cleaner light duty types of air cleanerThis question was posed to me in an internship interview.I want to ask this question from Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The CORRECT option is (c) Heavy-duty type air CLEANER Easiest explanation: Heavy-duty type air cleaner is also known as an oil bath type wherein the filter is saturated with oil. The air from the atmosphere enters through the circumferential gap and around the corner the air takes a TURN and large particle IMPURITIES are left.

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62.	When an air cleaner gets clogged with dirt. How are the airflow,Engine performance, and fuel consumption respectively?(a) Increase, sluggish, lower(b) Decrease, sluggish,higher(c) Increase, better, lower(d) Has no effectThe question was asked during a job interview.This interesting question is from Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right CHOICE is (b) Decrease, sluggish,higher The explanation: When the air cleaner gets clogged the airflow gets DECREASED, resulting in sluggish engine performance and higher CONSUMPTION of fuel. Therefore, it should be cleaned regularly or replaced periodically for EVERY 20,000kms.

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63.	Which among the following is a function of an air cleaner concerning the carburation system?(a) Reducing agent(b) Catalyst(c) Silencer(d) VentilationThe question was asked during an internship interview.The question is from Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right option is (c) Silencer To explain: The air CLEANER acts as a silencer for the carburation system as it REDUCES the ENGINE INDUCTION noise to an acceptable LEVEL. The air cleaner is the most important part as hundreds of cubic meters of air per hour are used by the engine of an automobile.

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64.	Which part of the engine does not rapidly wear due to impurities like dust?(a) Cylinder(b) Pistons(c) Rings(d) CamshaftI have been asked this question in an interview for internship.This intriguing question comes from Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The CORRECT option is (d) Camshaft Easy explanation: The impurities like dust in the air CAUSE very rapid wear of the engine, particularly the cylinder, piston, rings, VALVES, and guides. Whereas the camshaft is not part of the cylinder as the camshaft just HELPS in the valve TIMING.

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65.	Which among the following is a function of air cleaner when the engine back-fires?(a) Flame arrester(b) Diffuser(c) Flame arrester and Diffuser(d) Pressure relieverI had been asked this question in unit test.Origin of the question is Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right answer is (a) FLAME arrester To explain: The ENGINE backfires, the air cleaner ALSO acts as a flame arrester. However, resistance to the airflow which is increased as the air cleaner GETS clogged with DUE to which the engine performance would get decreased.

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66.	Which property of the diaphragm return spring helps in the determination of the exact pressure range?(a) Tension(b) Stress(c) Starin(d) StiffnessI had been asked this question in an international level competition.My doubt stems from Petrol Engine Fuel Supply System topic in section Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The correct CHOICE is (d) Stiffness To explain I would say: The exact PRESSURE range being determined by the stiffness of the diaphragm return SPRING. The controlled pressure in the PETROL supply line is very important to be maintained. If the pressure is low, the petrol supply will not be able to keep pace with the demand under HIGH speed or high load conditions.

Discussion

67.	In which system the pump starts to operate immediately as the ignition is switched on?(a) A.C mechanical pump(b) S U electrical pump(c) A.C mechanical pump & S U electrical pump(d) Mechanical pumpI had been asked this question in class test.This intriguing question originated from Petrol Engine Fuel Supply System in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct answer is (B) S U electrical pump The best I can explain: In an S U electrical pump the electric pump needs not to WAIT for the engine to start. It starts to OPERATE immediately as the ignition is SWITCHED on. Whereas the A-C MECHANICAL pump does not have this advantage.

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68.	Which of the following has the requirement of placing the pump necessarily close to the engine ?(a) A.C mechanical pump(b) S U electrical pump(c) A.C mechanical pump & S U electrical pump(d) Electric pumpThis question was posed to me in final exam.My question is based upon Petrol Engine Fuel Supply System topic in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» RIGHT option is (a) A.C mechanical pump Easy explanation: The pump need notbe SITUATED close to the engine in S U electrical pump therefore in the A.C mechanical type the pump needs to be situated close to the engine THUS they are subjected to engine heat.

Discussion

69.	Which of the following component movement interrupts the electrical supply by disconnecting the breaker points?(a) Float chamber(b) Diaphragm(c) Strainer(d) ArmatureThe question was posed to me in a job interview.I need to ask this question from Petrol Engine Fuel Supply System topic in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» CORRECT option is (d) ARMATURE Easiest EXPLANATION: The armature moves, it interrupts the electric supply by disconnecting the breaker points. Due to which the solenoid is de-energized and the armature falls BACK, CAUSING the diaphragm to move to create pressure in the pump chamber.

Discussion

70.	Which system experiencesVapour locking in the fuel system?(a) A.C mechanical pump(b) S U electrical pump(c) Both A.C mechanical pump and S U electrical pump(d) Electrical pumpThe question was posed to me in my homework.My question is based upon Petrol Engine Fuel Supply System topic in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct answer is (a) A.C mechanical PUMP The BEST explanation: SINCE the A-C pump is situated close to the engine due to which they are exposed to engine heat, which may RESULT in vapor LOCKING in the fuel system. Which is taken care of by the diaphragm return spring.

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71.	Which of the following is the correct sequence of fuel travel?(a) Tank – fuel pump – fuel filter – carburetor(b) Tank – fuel filter – fuel pump – carburetor(c) Fuel filter – fuel pump – tank – carburetor(d) Carburetor – fuel pump – fuel filter – tankI have been asked this question during an interview.Question is taken from Petrol Engine Fuel Supply System in chapter Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right choice is (a) TANK – fuel pump – fuel FILTER – carburetor The explanation is: The fuel flows from the fuel tank to the fuel pump where the fuel is pumped to high PRESSURE and then the high-pressure fuel enters the filter and the dust and retained in the filtered and then the fuel is SENT into the carburetor.

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72.	Which valve opens when the downward movement of the diaphragm causes a vacuum in the chamber?(a) Outlet(b) Inlet(c) Both outlet and inlet(d) TransferThis question was posed to me by my college director while I was bunking the class.My question is based upon Petrol Engine Fuel Supply System topic in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The CORRECT choice is (b) Inlet The best explanation: The Downward movement of the diaphragm causes a vacuum in the CHAMBER which causes the inlet valve to open. This vacuum HELPS in the suction of the oil and is one of the most important processes in pump operation.

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73.	Which type of energy is used to operate the diaphragm in an S U electrical pump?(a) Mechanical(b) Hydraulic(c) Electrical(d) SolarThis question was posed to me by my school teacher while I was bunking the class.My question comes from Petrol Engine Fuel Supply System in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» The correct option is (c) Electrical Easy explanation: Alternate vacuum and PRESSURE are PRODUCED due to movement of the diaphragm which is caused electrically in the S U electrical pump. Closing the ignition switch energies the solenoid winding, magnetic flux is GENERATED which pulls the ARMATURE to which diaphragm is attached.

Discussion

74.	Which material is used in the diaphragm of an A.C mechanical pump?.(a) Paper(b) Metal sheet(c) High-grade cotton and rubber(d) CeramicI got this question in examination.I'm obligated to ask this question of Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct choice is (C) High-grade cotton and rubber The explanation: The diaphragm used in the A.C MECHANICAL pump is made out of high-grade cotton IMPREGNATED with SYNTHETIC rubber. The downward movement of the diaphragm causes a vacuum in the chamber which causes the INLET valve to open.

Discussion

75.	Which of the following helps in the relief of the excess pressure which is built up?(a) Pull rod(b) Diaphragm return spring(c) Camshaft(d) Suction valveI got this question in an online quiz.My question is from Petrol Engine Fuel Supply System in section Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right option is (b) Diaphragm return spring Explanation: The pump will BUILD up excessive PRESSURE which may DAMAGE the pump itself. This is taken care of by the diaphragm return spring which remains partially or fully compressed DEPENDING UPON the line pressure.

Discussion

76.	Which of the following provides the force to drive the pump?(a) Crankshaft(b) Differential(c) Camshaft(d) V-beltI got this question in a national level competition.I'm obligated to ask this question of Petrol Engine Fuel Supply System topic in portion Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Correct choice is (c) CAMSHAFT To explain: The driving force the pump is taken from camshaft by the means of ECCENTRIC or CAM. The eccentric cam operates the ROCKER arm which is in conjunction with the diaphragm return spring pushes the diaphragm up and down.

Discussion

77.	What is the pressure range in kPa in the petrol pipeline between the fuel pump and the carburetor?(a) 5-10(b) 10-20(c) 20-35(d) 35-40This question was addressed to me during an online exam.My question is from Petrol Engine Fuel Supply System topic in division Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» Right ANSWER is (c) 20-35 The EXPLANATION: The pressure in the petrol pipeline between the FUEL PUMP and the carburetor, is kept under the pressure between about 20 and 35kPa, the exact pressure RANGE being determined by the stiffness of the diaphragm return spring.

Discussion

78.	Which material is used for the valves of the A.C mechanical pump?(a) Cast iron(b) Plastic(c) Bakelite(d) PaperI got this question in an online quiz.This interesting question is from Petrol Engine Fuel Supply System topic in section Petrol Engine Fuel Supply System of Automotive Engine Design
Answer» RIGHT answer is (c) BAKELITE To explain I would say: The A.C pump’s valves are MADE up of Bakelite, which being lighter KEEPS the inertia stresses minimum and they are resistant to heat, scratches, and destructive SOLVENTS which makes it be most commonly used.

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Which material is used for the valves of the A.C mechanical pump?(a) Cast iron(b) Plastic(c) Bakelite(d) PaperI got this question in an online quiz.This interesting question is from Petrol Engine Fuel Supply System topic in section Petrol Engine Fuel Supply System of Automotive Engine Design