MCQOPTIONS
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MCQOPTIONS
This section includes 471 Mcqs, each offering curated multiple-choice questions to sharpen your Uncategorized topics knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Increased temperature of inlet air, causes volumetric efficency of engine to |
| A. | increase |
| B. | decrease |
| C. | remains same |
| D. | same of the above |
| Answer» C. remains same | |
| 202. |
In SI engines flame speed decreases with increase in |
| A. | intake temperature |
| B. | peak temperature |
| C. | compression ratio |
| D. | residual gases |
| Answer» E. | |
| 203. |
Modern carburettor provide the correct quality of air-fuel mixture during |
| A. | starting |
| B. | idling |
| C. | cruising |
| D. | all conditions |
| Answer» E. | |
| 204. |
Air-fuel mixture required for condition of best fuel economy and maximum power is |
| A. | same at all working conditions of an engine |
| B. | same at a region close to stoichiometric conditions |
| C. | is different at all working conditions of an engine |
| D. | none of the above |
| Answer» E. | |
| 205. |
A simple carburettor supplies rich mixture during |
| A. | starting |
| B. | idling |
| C. | cruising |
| D. | acceleration |
| Answer» D. acceleration | |
| 206. |
During no load (idling) running of engine, the throttle valve is kept slmodt in closed position. A simple carburettor will provide |
| A. | rich mixture |
| B. | stoichiometric mixture |
| C. | extreamly lean mixture |
| D. | none of the above |
| Answer» D. none of the above | |
| 207. |
A:F ratio needed for minimum specific fuel consumption of S.I. engine is, |
| A. | 12 to 14:1 |
| B. | 1970-01-01 15:01:00 |
| C. | 16.5 to 17.5:1 |
| D. | 18 to 20:1 |
| Answer» D. 18 to 20:1 | |
| 208. |
In multi cylinder engines,in all the cylinders I. Air-fuel ratio is same, II.Air-fuel ratio is different |
| A. | only i is true |
| B. | only i is false |
| C. | both i and ii are true |
| D. | none of the above |
| Answer» C. both i and ii are true | |
| 209. |
what is the air fuel ratio of the engine, if the air consumtion I s0.00721 kg per second and fuel consumtion I s0.00035kg per se |
| A. | 17.6 |
| B. | 0.04854 |
| C. | 0.00721 kg/se |
| D. | 0.00531 kg/sec |
| Answer» C. 0.00721 kg/se | |
| 210. |
To develop maximum power, mixture supplied is |
| A. | rich |
| B. | chemically correct |
| C. | lean |
| D. | none of the above |
| Answer» B. chemically correct | |
| 211. |
what would be the air fuel ratio ot the engine if the air consumtion time for 0.1 cubic meter as 16.3 sec and whose density is 1.175kg per cubic meter and fuel consumtion time for 10 cc as 20.sec whos specific gravity is 0.7 . |
| A. | 17.6 |
| B. | 19.6 |
| C. | 18.6 |
| D. | 20.6 |
| Answer» E. | |
| 212. |
Maximum pressure pobtained in SI engine duering motoring is about |
| A. | 2 bar |
| B. | 15 bar |
| C. | 8 bar |
| D. | 40 bar |
| Answer» D. 40 bar | |
| 213. |
Favourable conditions for combustion are: 1. The presence of combustible mixture 2. Initiation by any means like spark plug is not required 3. Stabilization and propagation of flame in the combustion chamber. Out of these following is correct |
| A. | all are correct |
| B. | i and iii |
| C. | ii and iii |
| D. | i and ii |
| Answer» C. ii and iii | |
| 214. |
Maximum heat energy is liberated during |
| A. | ignition lag |
| B. | preparation phase |
| C. | propagation of flame |
| D. | after burning |
| Answer» D. after burning | |
| 215. |
A motoring curve is plotted when |
| A. | when the vehicle is not running |
| B. | when engine is running at no load condition |
| C. | the cycle is taking place due to combustion of fuel |
| D. | the cycle is not fired |
| Answer» E. | |
| 216. |
a six cylinder four stroke petrol engine develops a indicated power of 67.593 KW with indicated mean specific fuel consumption os 0.3kg/Kwh. What would be the mas flow rate of the fuel in kg/hr |
| A. | 25.369 |
| B. | 18.658 |
| C. | 20.278 |
| D. | 19.365 |
| Answer» D. 19.365 | |
| 217. |
During starting, richer mixture is sent through carburetor because |
| A. | it is transient condition |
| B. | it is steady condition |
| C. | it provides heavy ends of fuel in cylinder |
| D. | it provides light ends of fuel in cylinder |
| Answer» D. it provides light ends of fuel in cylinder | |
| 218. |
During cold starting, richer mixture is provided |
| A. | because lean mixture is created in cylinder because of less vapourized fuel availability in air. |
| B. | because lean mixture is created in cylinder because of less fuel availability in air. |
| C. | because lean mixture is created in cylinder because of more air availability in same quantity of fuel. |
| D. | all of the above |
| Answer» B. because lean mixture is created in cylinder because of less fuel availability in air. | |
| 219. |
During combustible mixture preparation process fuel droplets are vaporized in |
| A. | carburetor |
| B. | carburetor and intake manifold |
| C. | carburetor, intake manifold and cylinder |
| D. | all of the above |
| Answer» D. all of the above | |
| 220. |
a four cylinder petrol engine with 70mm bore and 100 mm stroke length working on four stroke pricniple develops a torque 140 N-m at 4000 rpm what would be the brake power of the engine ? |
| A. | 58.65kw |
| B. | 63.25kw |
| C. | 48.35kw |
| D. | 33.32kw |
| Answer» B. 63.25kw | |
| 221. |
In S I Engine homogeneous mixture is prepared in |
| A. | combustion chamber |
| B. | intake manifold |
| C. | carburetor |
| D. | exhaust valve |
| Answer» D. exhaust valve | |
| 222. |
__________ is the process of preparation of mixture of fuel and air before admission to cylinder. |
| A. | mixing |
| B. | carburettion |
| C. | evaporation |
| D. | condensation |
| Answer» C. evaporation | |
| 223. |
what would be the heat supplied to the engine in KJ/s, if the engine consumes 8 lit of gasoline per second. Take caloric value and density of fuel is 44000 kj/kg and 800 kg per cubic meter resp. |
| A. | 8.48 |
| B. | 9.78 |
| C. | 7.35 |
| D. | 4.35 |
| Answer» C. 7.35 | |
| 224. |
A-fuel mixture in the SI engine is prepared |
| A. | in the clearance volume in cylinder of engine |
| B. | can be prepared anywhere outside the cylinder |
| C. | prepared in the carburetor outside the cylinder |
| D. | prepared in the carburetor inside the cylinder |
| Answer» D. prepared in the carburetor inside the cylinder | |
| 225. |
Mixture requirements by the engine part load running ( cruising range) is, |
| A. | rich |
| B. | chemically correct |
| C. | lean |
| D. | cant say |
| Answer» D. cant say | |
| 226. |
To have minimum specific fuek consumption ot to achieve maximum economy of fuel, mixture supplied is |
| A. | rich |
| B. | chemically correct |
| C. | lean |
| D. | none of the above |
| Answer» D. none of the above | |
| 227. |
In SI engines flame speed always increases with____ |
| A. | turbulence |
| B. | air-fuel ratio |
| C. | residual gases |
| D. | compression ratio |
| Answer» E. | |
| 228. |
In the ignition lag phase of SI engine following things happens |
| A. | growth and development of semi propagating nucleus of flame. |
| B. | its just temperature rise phase |
| C. | its just pressure rise phase. |
| D. | all of the above |
| Answer» B. its just temperature rise phase | |
| 229. |
what would be the heat supplied to the engine in KJ/s, if the engine consumes 8 lit of gasoline per second. Take caloric value and specific gravity of fuel is 44000 kj/kg and 0.8 resp. |
| A. | 9.78 |
| B. | 8.48 |
| C. | 7.35 |
| D. | 4.35 |
| Answer» B. 8.48 | |
| 230. |
In the rich mixturers used for automobile applications |
| A. | fuel quantity is more than stoichiometric quantity |
| B. | air quantity is more than stoichiometric quantity |
| C. | both the quantities are same |
| D. | fuel quantity is more than the air quantity. |
| Answer» B. air quantity is more than stoichiometric quantity | |
| 231. |
Which is not drawback of simple carburetor? |
| A. | it provides required air fuel ratio at all throttle position |
| B. | it supplies increasingly rich mixture as speed increases |
| C. | it provides very lean mixtures at low speeds |
| D. | none of the above |
| Answer» E. | |
| 232. |
Separation of combustion curve from motoring curve in SI engine takes place |
| A. | when crank angle is about 10 deg. before tdc |
| B. | when crank angle is about 10 deg. after tdc |
| C. | when crank angle is about 10 deg. before bdc |
| D. | when crank angle is about 10 deg. after bdc |
| Answer» B. when crank angle is about 10 deg. after tdc | |
| 233. |
In carburetor, throttle valve is located on which side of the venturi? |
| A. | engine side |
| B. | air filter side |
| C. | at the venturi |
| D. | any where |
| Answer» B. air filter side | |
| 234. |
At high speed of engine and for fully open position of throttle valve. |
| A. | more air-fuel mixture it send to cylinder. |
| B. | less air-fuel mixture it send to cylinder. |
| C. | more air mixture it send to cylinder. |
| D. | less fuel mixture it send to cylinder. |
| Answer» B. less air-fuel mixture it send to cylinder. | |
| 235. |
If air fuel ratio is greater than 16:1 then ixture is |
| A. | lean |
| B. | chemically correct |
| C. | rich |
| D. | perfect |
| Answer» B. chemically correct | |
| 236. |
During combustion in SI engine heat is liberated due to reassociation of molecules in |
| A. | ignition lag |
| B. | preparation phase |
| C. | propagation of flame |
| D. | after burning |
| Answer» E. | |
| 237. |
Throttle valve is placed on which side of venturi |
| A. | on atmospheric air side |
| B. | at venturi |
| C. | before venturi |
| D. | after venturi |
| Answer» E. | |
| 238. |
A:F ratio used during part load running cruising range from |
| A. | 11 to 14:1 |
| B. | 1970-01-01 15:01:00 |
| C. | 16 to 17.5:1 |
| D. | 18 to 20:1 |
| Answer» D. 18 to 20:1 | |
| 239. |
During cruising of S I engine |
| A. | richer mixture is required |
| B. | leaner mixture is required |
| C. | both of the above |
| D. | nothing is right |
| Answer» C. both of the above | |
| 240. |
Cruising speed of S I engine is |
| A. | high speed working condition of an engine |
| B. | normal working condition of an engine |
| C. | full load working condition of an engine |
| D. | all of the above |
| Answer» C. full load working condition of an engine | |
| 241. |
Pressure at the throat at fully open position of throttle condition lies in between |
| A. | 1 to 2 mm hg below atmospheric pressure |
| B. | 10 to 20 mm hg below atmospheric pressure |
| C. | 4 to 5 mm hg below atmospheric pressure |
| D. | 0.5 to 2 mm hg below atmospheric pressure |
| Answer» D. 0.5 to 2 mm hg below atmospheric pressure | |
| 242. |
Operating the choke in cold starting means |
| A. | closing the choke valve |
| B. | opening the choke valve |
| C. | opening the throttle valve more |
| D. | closing the throttle valve |
| Answer» B. opening the choke valve | |
| 243. |
For maximum thermal efficincy, the fuel-air ratio mixture in SI engines should be |
| A. | lean |
| B. | rich |
| C. | stoichiometric |
| D. | may be lean or rich |
| Answer» B. rich | |
| 244. |
In the simple carburetor which of the following modification is necessory for increasing air flow to compenset for rich mixture |
| A. | compensating jet |
| B. | emulsion tube |
| C. | back suction control |
| D. | all of the above |
| Answer» E. | |
| 245. |
Maximum fuel economy occurs on the side of following air fuel ratio |
| A. | small value of air-fuel ratio |
| B. | large value of air-fuel ratio |
| C. | depends on the working condition of si engine |
| D. | none of the above |
| Answer» C. depends on the working condition of si engine | |
| 246. |
During acceleraton lean mixture is reached in cylinder because |
| A. | more quantity of fuel is vaporized but not sent in cylinder during working of the cylinder |
| B. | during acceleration intake manifold is supporting the working of carburetor as more and more fuel is sent to intake manifold instantly from the carburetor |
| C. | because more fuel is consumed during acceleration and hence we send leaner mixture |
| D. | fuel lags behind in intake manifold as vaporized fuel is passed in the cylinder and more fuel is collected in intake manifold which is not vaporized during subsequent strokes as during normal working conditions of engine |
| Answer» E. | |
| 247. |
Dopes are___ |
| A. | chemical which will increase knocking tendency of fuel |
| B. | chemical which will decrease knocking tendency of fuel |
| C. | chemical which will decrese exhaust from engine |
| D. | chemical which will increse exhaust from engine |
| Answer» C. chemical which will decrese exhaust from engine | |
| 248. |
In the Lean mixturers used for automobile applications |
| A. | fuel quantity is more than stoichiometric quantity |
| B. | air quantity is more than stoichiometric quantity |
| C. | both the quantities are same |
| D. | fuel quantity is more than the air quantity. |
| Answer» C. both the quantities are same | |
| 249. |
Practical limits of air fuel ratio for combution in SI engines is |
| A. | 9 to 21 |
| B. | 5 to 10 |
| C. | 20 to 30 |
| D. | 5 to 30 |
| Answer» B. 5 to 10 | |
| 250. |
In carburetor, choke is located on which side of the venturi? |
| A. | engine side |
| B. | air filter side |
| C. | at the venturi |
| D. | any where |
| Answer» C. at the venturi | |