Internal Combustion Engines MCQs

Question 1

Iso-octane

Accepted Answer

Has octane number of 100

Answer

Has octane number of 0

Answer

Has octane number of 50

Answer

Is an index of detonation quality

Question 2

Octane number is determined by comparing the performance of the petrol with the following hydrocarbons

Accepted Answer

Mixture of normal heptane and iso-octane

Answer

Iso-octane

Answer

Alpha methyl napthalene

Answer

Mixture of methane and ethane

Question 3

Ethyl fluid is used

Accepted Answer

To increase the octane rating of the fuel

Answer

To increase the cetane rating of the fuel

Answer

As a defrosting agent

Answer

As a superior type of fluid compared to others

Question 4

The self-ignition temperature of diesel oil compared to petrol is

Accepted Answer

Lower

Answer

Higher

Answer

Same

Answer

Depends on quality of fuel

Question 5

Normal heptane

Accepted Answer

Helps to resist auto-ignition

Answer

Accelerates auto-ignition

Answer

Does not affect auto-ignition has no relation with auto-ignition

Answer

Retards auto-ignition

Question 6

Cetane number is determined by comparing the performance of diesel oil with the following hydrocarbons

Accepted Answer

Mixture of cetane and alphamethyl napthalene

Answer

Cetane

Answer

Ethylene dibromide

Answer

Mixture of aldehydes and ketones

Question 7

Which is correct statement about reaction time for auto-ignition of fuel and the fuel air ratio

Accepted Answer

All of the above

Answer

Lean mixture has high reaction time

Answer

Rich mixture has high reaction time

Answer

Chemically correct mixture has minimum reaction time

Question 8

Violent sound pulsations within the cylinder of an I.C. engine are caused due to

Accepted Answer

Detonation

Answer

Heavy turbulence

Answer

Improved scavenging

Answer

Heavy supercharging

Question 9

Auto-ignition temperature is

Accepted Answer

That at which it catches fire without external aid

Answer

Minimum temperature to which oil is heated in order to give off inflammable vapors in sufficient quantity to ignite momentarily when brought in contact with a flame

Answer

Temperature at which it solidifies or congeals

Answer

Indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off