Piston Engines - Fuel: DGCA Technical General questions

Question 1

In the internal combustion engine, detonation occurs due to:

Accepted Answer

excessive combustion temperatures and pressures

Answer

the use of too high an rpm with too little manifold pressure

Answer

the use of the wrong grade of oil

Answer

the cylinder temperatures and pressures being too low

Question 2

If the specific gravity of a fuel is known to be 0.7, 100 imperial gallons of it will weigh:

Accepted Answer

700 lb

Answer

70 lb

Answer

7000 lb

Answer

7100 lb

Question 3

The octane rating of a fuel is determined by comparison with mixtures of:

Accepted Answer

heptane and iso-octane

Answer

methane and orthodentine

Answer

methane and iso-octane

Answer

heptane and orthodentine

Question 4

Pre-ignition refers to the condition when:

Accepted Answer

the mixture is ignited by abnormal conditions within the cylinder before the normal ignition point

Answer

a rich mixture is ignited by the spark plug

Answer

the spark plug ignites the mixture too early

Answer

the mixture burns in the inlet manifold

Question 5

Diesel fuel (AVTUR) is:

Accepted Answer

heavier per unit volume than AVGAS

Answer

lighter per unit volume than AVGAS

Answer

more likely to ignite when exposed to a naked flame.

Answer

has less energy per unit volume than AVGAS.

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