# Farm Tractor Questions and Answers – Gasoline Tests

This set of Farm Tractor Multiple Choice Questions & Answers (MCQs) focuses on “Gasoline Tests”.

1. Optimum viscosity of fuel is needed for proper operation.
a) True
b) False

Explanation: The viscosity is the resistance to flow by the fluid. The higher and lower viscosity will result in injection system issues. It should be adhering to ASTM D445 standards.

2. What is called as ignition of fuel itself under higher temperature instead of ignition from the spark plug?
a) Detonation
b) Volatility
c) Viscosity
d) Ignition

Explanation: Detonation is a process of spontaneous combustion of a few amounts of the air-fuel mixture in the cylinder of internal combustion engines, but before the actual ignition and not in the normal flame front. It can cause higher pressure inside the piston cylinder and there will be a pinging sound. It is called as knocking.

3. What is called as measuring the tendency of gasoline/petrol in resisting detonation?
a) Detonation number
b) Knocking number
c) Octane number
d) Resistance number

Explanation: Octane value is a number given to fuel according to a special standard test with reference to a mixture of fuels under standard conditions. If the octane number is low for petrol, it will be more prone to knocking. If it is higher, the fuel can withstand the higher compression and there will be no chance for knocking.

4. How the time period between the fuel injection and fuel combustion is denoted?
a) Delay period
b) Combustion period
c) Dormancy time
d) No ignition time

Explanation: The ignition delay occurs in the diesel engines due to the mixing of fuels and pre-combustion reactions known as physical and chemical delays respectively. It should be short for the efficient operation of an engine.

5. What is the use of Reid vapour pressure test?
a) To find viscosity
b) To find volatility
c) To calculate cetane number
d) To calculate octane number

Explanation: Volatility is the quality of a material describing the readiness of vaporization of it. The test will result in the values of vapour pressure exerted by the vapour of the fuel under the standard conditions prescribed by the American Society for Testing and Materials (ASTM). It can also be determined by distillation test.

6. What is the purpose of the cetane number?
a) Ignition quality of diesel
b) Ignition quality of petrol
c) Quantity of fuel
d) Knocking

Explanation: Cetane number is a counterpart of octane value i.e. for diesel fuel. It is the value for indicating the fuel’s combustion rate. Generally, the cetane number for diesel engines is in the range of 48 to 50. The lower cetane number can have a longer delay period.

7. Find cetane number for the mixture of 40% n-cetane and 60% heptamethylnonane?
a) 50
b) 49
c) 48
d) 40

Explanation:
CN = 100 * (percentage of n-cetane) + 15 * (percentage of heptamethylnonane)
= 100 * (0.40) + 15 (0.60)
= 49
Where 100 and 15 are cetane numbers of them respectively.

8. The reasons for diesel additives are to improve engine performance and protection of the engine.
a) True
b) False

Explanation: The diesel fuel additives are for fuel stability, corrosion inhibition, engine protection, raising cetane number of fuel etc. It is added at different stages like refinery, distribution system and so on. It is needed more for diesel fuel than gasoline.

9. How gum formation occurs in fuel?
a) Fuel quality
b) Oxidation
d) Reduction

Explanation: The gum formation occurs when the fuel is stored in the tank due to oxidation reaction. The gum may be in the form of solid or viscous liquid. Sometimes additives are added to fuel to reduce gums which can cause problems in intake manifolds.

10. Which is called as the lowest temperature at which the fuel gets ignited by an external source?
a) Flashpoint
b) Fire point
c) Pour point
d) Cloud point

Explanation: The flash point is not so significantly considered in engine performance. At the flashpoint, the fuel cannot sustain to combustion for a long time. The fire point is similar to flashpoint but at this point, fuel keeps combusting even after the removal of an external source of combustion.

Sanfoundry Global Education & Learning Series – Farm Tractor.

To practice all areas of Farm Tractor, here is complete set of Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]