McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Uncategorized topics .
| 201. |
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» B. air quantity is more than stoichiometric quantity | |
| 202. |
Stoichiometric air fuel ratio suggests |
| A. | correct quantity of fuel -air ratio which gives more economy |
| B. | correct quantity of fuel -air ratio which gives more power |
| C. | correct quantity of fuel -air ratio which gives complete combustion |
| D. | all of the above |
| Answer» C. correct quantity of fuel -air ratio which gives complete combustion | |
| 203. |
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» A. 9 to 21 | |
| 204. |
Practical limits of fuel air ratio for combution in SI engines is |
| A. | 0.11 to 0.05 |
| B. | 0.2 to 0.1 |
| C. | 0.05 to 0.033 |
| D. | 0.2 to 0.033 |
| Answer» A. 0.11 to 0.05 | |
| 205. |
Practical limits for air fuel ratio in SI engines provides |
| A. | range of air fuel ratio which gives comfortable working of si engine |
| B. | range of air fuel ratio to get combustion close to stochiometric conditions in si engine |
| C. | range of air fuel ratio for obtaining maximum power in si engine |
| D. | all of the above |
| Answer» B. range of air fuel ratio to get combustion close to stochiometric conditions in si engine | |
| 206. |
SI engine is also called as |
| A. | petrol engine |
| B. | gasoline engine |
| C. | spark ignition engine |
| D. | all of the above |
| Answer» D. all of the above | |
| 207. |
SI engine is also called as |
| A. | auto ignition engine |
| B. | compression ignition engine |
| C. | otto engine |
| D. | diesel engine |
| Answer» C. otto engine | |
| 208. |
Ignition limits in the SI engine depends upon |
| A. | mixture ratio and temperature |
| B. | volumetric efficiency and temperature |
| C. | engine size and volumetric efficiency |
| D. | mixture ratio and engine size |
| Answer» A. mixture ratio and temperature | |
| 209. |
Correct sequence of combustion stages in SI engine is |
| A. | propagation of phase,ignition phase and after burning |
| B. | preparation phase,propagation of flame and after burning |
| C. | propagation of phase,preparation phase and after burning |
| D. | after burning,propagation of phase and preparation phase |
| Answer» B. preparation phase,propagation of flame and after burning | |
| 210. |
Maximum pressure pobtained in SI engine duering motoring is about |
| A. | 2 bar |
| B. | 15 bar |
| C. | 8 bar |
| D. | 40 bar |
| Answer» C. 8 bar | |
| 211. |
Pressure during motoring in SI engine compared to CI engine is |
| A. | less |
| B. | more |
| C. | same |
| D. | none of the above |
| Answer» A. less | |
| 212. |
Maximum pressure in SI engine is about |
| A. | 10 bar |
| B. | 70 bar |
| C. | 50 bar |
| D. | 30 bar |
| Answer» D. 30 bar | |
| 213. |
SI engine contains homogeneous mixture of |
| A. | only vaporized fuel and oxygen |
| B. | fuel and air |
| C. | vaporized fuel,air and residual gases |
| D. | vaporized fuel,oxygen and residual gases |
| Answer» C. vaporized fuel,air and residual gases | |
| 214. |
Approximate tempearture between electrodes of spark plug is |
| A. | 5,000 deg. celsius |
| B. | 20,000 deg. celsius |
| C. | 2,000 deg. celsius |
| D. | 10,000 deg. celsius |
| Answer» D. 10,000 deg. celsius | |
| 215. |
Flame advancement from the start of formation of first nucleus of combustion depends on |
| A. | temperature of flame front itself, density of surrounding mixture and temperature inside of cylinder. |
| B. | only temperature of flame front itself, |
| C. | temperature of flame front itself and density of surrounding mixture |
| D. | only pressure and temperature inside cylinder |
| Answer» A. temperature of flame front itself, density of surrounding mixture and temperature inside of cylinder. | |
| 216. |
The preparation phase in SI engine will take about |
| A. | 20 deg. of crank angle |
| B. | 40 deg of crank angle |
| C. | 30 deg. of crank angle |
| D. | 10 deg. of crank angle |
| Answer» A. 20 deg. of crank angle | |
| 217. |
The peak pressure in SI engine will be observed when crank angle is |
| A. | about 10 deg. before tdc |
| B. | about 10 deg. after tdc |
| C. | at tdc |
| D. | at bdc |
| Answer» B. about 10 deg. after tdc | |
| 218. |
The first phase of combustion in SI engine is named as |
| A. | ignition lag |
| B. | preparation phase |
| C. | both a and b |
| D. | none of the above |
| Answer» C. both a and b | |
| 219. |
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» A. growth and development of semi propagating nucleus of flame. | |
| 220. |
Ignition lag in SI engine depends on following parameters |
| A. | only b |
| B. | nature of fuel,pressure and temperature |
| C. | temperature coefficient, proportion of exhaust gases |
| D. | both b and c |
| Answer» D. both b and c | |
| 221. |
Temperature Coeficient of the fuel is |
| A. | relation between temperature ,the rate of acceleration of oxidation or burning and pressure |
| B. | relation between temperature and the rate of acceleration of oxidation or burning. |
| C. | relation between temperature and the rate of acceleration of oxidation or burning. |
| D. | relation between temperature and pressure. |
| Answer» B. relation between temperature and the rate of acceleration of oxidation or burning. | |
| 222. |
Ignition lag phase is also |
| A. | mechanical process |
| B. | mechanical and chemical process |
| C. | chemical process |
| D. | none of the above |
| Answer» C. chemical process | |
| 223. |
Start of second phase in the combustion of SI engine is indicated by |
| A. | separation of velocity line from compression line on p-Ө diagram. |
| B. | constant pressure on p-Ө diagram. |
| C. | fall of pressure p-Ө diagram. |
| D. | separation of combustion curve from motoring curve on p-Ө diagram. |
| Answer» D. separation of combustion curve from motoring curve on p-Ө diagram. | |
| 224. |
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» A. when crank angle is about 10 deg. before tdc | |
| 225. |
First measurable rise of pressure in SI engine takes place approximately |
| A. | when crank angle is about 10 deg. after tdc |
| B. | when crank angle is about 10 deg. before 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. before tdc | |
| 226. |
Maximum heat energy is liberated during |
| A. | ignition lag |
| B. | preparation phase |
| C. | propagation of flame |
| D. | after burning |
| Answer» C. propagation of flame | |
| 227. |
Which phase of combustion takes place during expansion stroke |
| A. | ignition lag |
| B. | preparation phase |
| C. | propagation of flame |
| D. | after burning |
| Answer» D. after burning | |
| 228. |
During propagatuion of flame in SI engine crank rotates by about |
| A. | 20 deg. |
| B. | 40 deg. |
| C. | 30 deg. |
| D. | 10 deg. |
| Answer» A. 20 deg. | |
| 229. |
During afterburning phase in SI engine crank rotates by about |
| A. | 20 deg. |
| B. | 190 deg. |
| C. | 170 deg. |
| D. | 10 deg. |
| Answer» C. 170 deg. | |
| 230. |
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» D. after burning | |
| 231. |
Gap size in spark plug electrodes is about |
| A. | 10 to 20mm |
| B. | 1 to 2 mm |
| C. | 0.01 mm to 0.1 mm |
| D. | none of the above |
| Answer» B. 1 to 2 mm | |
| 232. |
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» C. prepared in the carburetor outside the cylinder | |
| 233. |
Volatility property of the fluid helps in |
| A. | increasing vaporization of fuel |
| B. | decreasing vaporization of fuel |
| C. | can increase or decrease vaporization |
| D. | none of the above |
| Answer» C. can increase or decrease vaporization | |
| 234. |
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» C. carburetor, intake manifold and cylinder | |
| 235. |
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» B. large value of air-fuel ratio | |
| 236. |
The important factors which significantly affects process of carburetion are |
| A. | time available for preparation of mixture |
| B. | the temperature of intake air in the intake manifold |
| C. | design of the induction system and combustion chamber |
| D. | all of the above |
| Answer» D. all of the above | |
| 237. |
The important factors which significantly affects process of carburetion are |
| A. | time available for preparation of mixture |
| B. | the temperature of exhaust gases in the exhaust manifold |
| C. | design of the induction system and combustion chamber |
| D. | both a and d |
| Answer» D. both a and d | |
| 238. |
For high speed S I engines following things occurs |
| A. | less time available for mixture preparation |
| B. | more time available for mixture preparation |
| C. | it varies with fuel properties |
| D. | all of the above |
| Answer» A. less time available for mixture preparation | |
| 239. |
Volatility of the fuel affects following processes in S I engine |
| A. | mixing of fuel with air |
| B. | vaporization and distribution of fuel |
| C. | both a and b |
| D. | none of the above |
| Answer» C. both a and b | |
| 240. |
Stoichiometric condition in S I Engine is such that |
| A. | it creates some pollutants with combustion of fuel and air mixture |
| B. | it gives complete combustion of the air fuel mixture |
| C. | exact quantity of the air is mixed with fuel to burn mixture effectively |
| D. | both b and c |
| Answer» D. both b and c | |
| 241. |
When SI engine is Idling |
| A. | leaner mixture is required |
| B. | mixture close to stoichiometric condition is needed |
| C. | richer mixture is required |
| D. | it may vary with atmospheric condition |
| Answer» C. richer mixture is required | |
| 242. |
Idling condition of the SI engine is |
| A. | when engine is running but no power out put from crank shaft |
| B. | when engine is running but power is produced from crankshaft |
| C. | when engine is not running but power out put from crank shaft |
| D. | only crankshaft is rotating |
| Answer» A. when engine is running but no power out put from crank shaft | |
| 243. |
When SI Engine is idling mixture enrichment is done |
| A. | to produce maximum power which is required during idling. |
| B. | for compensating diluted mixture in the cylinder because of exhaust gases in the cylinder which remains in previous stroke. |
| C. | both a and b |
| D. | none of the above |
| Answer» B. for compensating diluted mixture in the cylinder because of exhaust gases in the cylinder which remains in previous stroke. | |
| 244. |
For full load on S I engine following changes should be made in mixture prparation |
| A. | mixture should be prepared with fuel quantity increased |
| B. | mixture should be prepared with fuel quantity decreased |
| C. | mixture should be prepared with fuel and air quantity decreased |
| D. | mixture should be prepared with fuel and air quantity increased |
| Answer» A. mixture should be prepared with fuel quantity increased | |
| 245. |
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» B. leaner mixture is required | |
| 246. |
With increasing Air-Fuel ratio in S I engine Maximum power |
| A. | increases in the leaner region of the mixture |
| B. | decreases in the richer region of the mixture |
| C. | first increases up to a point at which maximum power is obtained and then it is decreases on the leaner side of the mixture |
| D. | all of the above |
| Answer» C. first increases up to a point at which maximum power is obtained and then it is decreases on the leaner side of the mixture | |
| 247. |
Maximum efficiency from the S I engine can be obtained |
| A. | at any air fuel ratio |
| B. | depends on working condition of the engine |
| C. | leaner mixture region compared to stoichiometric conditions |
| D. | in the region of richer air-fuel ratio compared to stoichiometric conditions |
| Answer» D. in the region of richer air-fuel ratio compared to stoichiometric conditions | |
| 248. |
Fuel economy from the engine can be expected |
| A. | when engine is running at normal speed |
| B. | when engine is running at very very low speed |
| C. | when engine is running at high speed |
| D. | when engine is running at very very high speed |
| Answer» A. when engine is running at normal speed | |
| 249. |
Fuel economy should not be expected in SI engine for which following cases |
| A. | when vehicle is climbing on hills |
| B. | when engine is pulling large quantity water from well |
| C. | both a and b |
| D. | only a |
| Answer» C. both a and b | |
| 250. |
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» B. normal working condition of an engine | |
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