MECHANICAL ENGINEERING

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1 Serial : 0 PT_ME_A+B_IC Engine_6098 CLASS TEST Delhi Noida Bhoal Hyderabad Jaiur Lucknow Indore Pune Bhubaneswar Kolkata Patna Web: info@madeeasy.in Ph: 0-56 MECHANICAL ENGINEERING I.C. Engine Duration:.00 hr. Maximum Marks: 50 Read the following instructions carefully. This question aer contains 0 objective questions. Q.-0 carry one mark each and Q.-0 carry two marks each.. Answer all the questions.. Questions must be answered on Objective Resonse Sheet (ORS) by darkening the aroriate bubble (marked A, B, C, D) using HB encil against the question number. Each question has only one correct answer. In case you wish to change an answer, erase the old answer comletely using a good soft eraser.. There will be NEGATIE marking. For each wrong answer /rd of the full marks of the question will be deducted. More than one answer marked against a question will be deemed as an incorrect resonse and will be negatively marked. 5. Write your name & Roll No. at the secified locations on the right half of the ORS. 6. Using HB encil, darken the aroriate bubble under each digit of your registration number. 7. No charts or tables will be rovided in the examination hall. 8. Use the blank ages given for rough work. 9. Choose the Closest numerical answer among the choices given. DO NOT OPEN THIS TEST BOOKLET UNTIL YOU ARE ASKED TO DO SO

2 Mechanical Engineering Q.No. to Q.No. 0 carry mark each Q. Which of the following engine tye as er stroke to bore ratio is suitable to oerate at higher seeds? (a) Over-square engine (b) Under-square engine (c) Square engine (d) Both (b) and (c) (d) 5 Q. The osition of the working iston and the moving arts which are mechanically connected to it, at the moment when the direction of iston motion is reversed at either end of the stroke is called the (a) Outer dead centre (b) Inner dead centre (c) To dead centre (d) Dead centre Q. Which of the following reresents ideal -v diagram of a four-stroke SI engine? Q. A high ressure fuel um and an injector are rovided in (a) CI engine (b) SI engines (c) Both CI and SI engines (d) Every IC Engines Q.5 SI engines. are of light weight. are of high seed. are having comression ratio of the order of 0-6 (a) and (b) and (c) and (d), and (a) 0 Q.6 Engines of different cylinder dimensions, ower and seed are comared on the basis of (a) unit ower (b) mean effective ressure (c) bore to stroke ratio (d) fuel consumtion Q.7 The intake charge in a diesel engine consists of (a) air alone (b) air + lubricating oil (c) air + fuel (d) air + fuel + lubricating oil (b) (c) 0 0 Q.8 Select the correct statement ertaining to twostroke engines:. It has uniform turning moment. Lower rate of wear and tear. Lower volumetric efficiency (a), and (b) and (c) and (d) only Q.9 Which of the following cylinder arrangements are inherently well balanced engines?. In-line engines. engines. Oosed cylinder engine. Oosed iston engine (a), and (b) and (c) only (d), and

3 CT-08 ME I.C. Engine Q.0 An IC engine gives an outut of kw when the inut is 000 J/s. The thermal efficiency of the engine is (a).% (b) 66.7% (c) 0% (d) 60% Q.No. to Q.No. 0 carry marks each Q. Disadvantage of hydrogen as an alternative fuel in IC engine: (a) Large vehicle range for a given fuel tank caacity (b) High NO x emissions (c) Difficult to refuel and the ossibility of detonation (d) ery difficult to store Q. arious tyes of nozzles are used in CI engines. Which of the following nozzle has the ability to distribute the fuel roerly even with lower air motion available in oen combustion chambers? (a) Simle hole nozzle (b) Multi-hole nozzle (c) Pintle nozzle (d) Pintaux nozzle Q. Pour oint of fuel oil is the (a) temerature at which if flows easily (b) it catches fire without external aid (c) temerature at which it solidifies or congeals (d) indicated by 90% distillation temerature of the engine is kw. What is the loss due to friction ower as the ercentage of brake ower? (a) 8.% (b) 9% (c) 9.% (d) 0.% Q.6 The b of a four-cylinder engine is 0 kw with all cylinder firing and 0 kw with one cylinder out. The mechanical efficiency is (a) 85% (b) 80% (c) 75% (d) 60% Q.7 An indicator from an engine has a length of 00 mm and an area of 000 mm. If the indicator ointer deflects 0 mm for a ressure increment of bar, the mean effective ressure is (a) bar (b) bar (c) 6 bar (d) 8 bar Q.8 Which of the following factors would increase the robability of knock in the CI engine?. Long ignition delay of fuel. Low self ignition temerature of fuel. Low combustion wall temerature (a), and (b) only (c) and (d) and Q.9 Effect of A/F ratio on ower outut of a CI engine is shown below: Q. The grah shown in the given figure reresents the emission of a ollutant from an CI engine for different F/A ratios. The ollutant in question is Power outut (kw) P Q R S Concentration Equivalence ratio, φ (a) CO (b) CO (c) HC (d) NO x Q.5 A single-cylinder engine running at 000 rm develos a torque of 8 N.m. The indicated ower A/F ratio isible objectionable smoke area would be reresented by region (a) S (b) R (c) Q (d) P Q.0 Knock in the SI engine can be reduced by. Suercharging. Advancing the sark timing. Increasing the engine seed. Using a fuel of long straight chain structure (a),, and (b) only (c) and (d), and

4 Mechanical Engineering Q. Consider the following statements regarding SI engine:. Highly volatile fuel is used.. Secific outut is lower than CI engine.. Its exhaust ollution is more as comared to CI engine.. Uer limit of comression ratio is fixed by anticlock quality of the fuel. Which of these statements are CORRECT? (a), and (b), and (c), and (d), and Q. An engine roduces 0 kw brake ower while working with a brake thermal efficiency of 0%. If the calorific value of the fuel used is 000 kj/ kg, then what is the fuel consumtion rate? (a). kg/h (b). kg/h (c).9 kg/h (d).95 kg/h Q. Consider the following curve: Bsfc BHP ariation of BSFC vs BHP for a CI engine running at constant seed is reresented by (a) curve (b) curve (c) curve (d) curve Q. Select the CORRECT statements regarding engine emissions and their control:. Exhaust gas recirculation reduces NO x emission.. Exhaust gas recirculation imroves thermal efficiency.. Catalytic converters are not very efficient when they are cold.. Sulhur degrades the catalytic converter and contributes to acid rain. (a), and (b), and (c), and (d), and Q.5 The -way catalytic converters control the following excet: (a) HC emission (c) NO x emission (b) CO emission (d) PM emission Q.6 Exhaust emission vs air fuel ratio curves for a SI engine are shown below. Select the correct combination. Emission A B A/F ratio (a) curve A HC; curve B CO; curve C NO x (b) curve A NO x ; curve B CO; curve C HC (c) curve A CO; curve B HC; curve C NO x (d) curve A CO; curve B NO x ; curve C HC Q.7 For minimizing knocking tendency in SI engine, the location of sark lug should be (a) at midway between inlet and exhaust valve (b) at midway between inlet and exhaust valve but nearer to inlet (c) at midway between inlet and exhaust valve but nearer to exhaust (d) very near to inlet valve Q.8 Diesel knock can be reduced by. increasing the comression ratio.. increasing the engine seed.. increasing the ignition temerature of fuel.. decreasing the inlet air temerature. (a) only (b) and (c), and (d) and Q.9 The cold start injector (a) maintain stoichiometric air-fuel ratio (b) rovides lean air-fuel ratio (c) gives rich air-fuel ratio (d) is not used for any of the above functions Q.0 Main advantage of intaux nozzle is (a) better cold starting erformance (b) ability to distribute the fuel evenly (c) good enetration (d) good atomization C

5 Serial : 0 PT_ME_A+B_IC Engine_6098 Delhi Noida Bhoal Hyderabad Jaiur Lucknow Indore Pune Bhubaneswar Kolkata Patna Web: info@madeeasy.in Ph: 0-56 CLASS TEST 08-9 MECHANICAL ENGINEERING Subject : I.C. Engine Date of test : 6/09/08 Answer Key. (a) 7. (a). (c) 9. (d) 5. (d). (d) 8. (c). (c) 0. (b) 6. (c). (a) 9. (b) 5. (c). (d) 7. (c). (a) 0. (a) 6. (c). (a) 8. (a) 5. (a). (c) 7. (c). (b) 9. (c) 6. (b). (b) 8. (d). (c) 0. (a)

6 6 Mechanical Engineering Detailed Exlanations. (a) If bore > stroke, the engine is called over-square engine. An over-square engine can oerate at higher seeds because of larger bore and shorter stroke.. (d) TDC and BDC Dead centres for vertical engine ODC and IDC Dead centres for horizontal engine So, dead centre is the answer.. (a) In CI engines, a high ressure fuel um and an injector are rovided to inject the fuel into the combustion chamber. 5. (a) Comression ratio of SI engines 6 to (a) In the CI engine during suction stroke, air, instead of a fuel-air mixture, is inducted. 8. (c). Because of one ower stroke in one revolution greater cooling and lubrication requirements. Higher rate of wear and tear is due to above in two-stroke engines.. -stroke engines has lower volumetric efficiency due to lesser time for mixture intake. 0. (a) η thermal Outut 0 Inut 0 In ercentage, η 00.%. (c) The our oint indicates the lowest temerature at which an oil stos flowing to the um, bearings or cylinder walls. It is articularly imortant for immediate oil circulation in resect of starting of engines in very cold climates with gravity lubricating systems the fluidity is a factor of our oint and viscosity of the cold oil. 5. (c) b π NT kW f i b kw Percentage loss %.675

7 CT-08 ME I.C. Engine 7 6. (c) i b b 0 0 0kW Similarly, i i i 0 kw i η m i i 0kW b or 75% i 0 7. (c) Height of indicator diagram 000 0mm 00 bar Mean effective ressure 0mm 6 bar 0mm 8. (d) To decrease the tendency of knock in CI engines: ignition delay should be short. combustion wall temerature should be high. 0. (b) (i). (d) Suercharging increases the knocking tendency as temerature of charge increases beyond ignition temerature. Long chain fuel structure have high tendency to knock in SI engine. (ii) (iii) Retarding the sark timing reduces knock in SI engine. and η CI > η SI (Power) SI > (Power) CI. (a) or η bth ṁ f BP m C f BP η C kg/hour bth. (c) EGR method of reducing NO x emission also reduces the thermal efficiency of the engine. 8. (a) Diesel knock can be reduced by decreasing the engine seed decreasing the ignition temerature of fuel increasing the inlet air temeratur

SAMPLE STUDY MATERIAL

IC Engine - ME GATE, IES, PSU 1 SAMPLE STUDY MATERIAL Mechanical Engineering ME Postal Correspondence Course Internal Combustion Engine GATE, IES & PSUs IC Engine - ME GATE, IES, PSU 2 C O N T E N T 1.