172) The ignition quality of petrol is expressed by

cetane number

octane number

calorific value

all of these

Answer is:

octane number

opens at 15 Degree after top dead centre and closes at 20 Degree before bottom dead centre

opens at 15 Degree before top dead centre and closes at 20 Degree after top dead centre

opens at top dead centre and closes at bottom dead centre

may open and close anywhere

Answer is:

not effect

decrease

increase

none of these

Answer is:

enhanced by decreasing compression ratio

enhanced by increasing compression ratio

dependent on other factors

none of the above

Answer is:

suction, compression, expansion and exhaust

suction, expansion, compression and exhaust

expansion, compression, suction and exhaust

compression, expansion, suction and exhaust

Answer is: