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# Automobile Engineering Interview Questions and Answers

Question - 1 : -
What is Automobile Engineering?

Automobile Engineering is a branch of engineering which deals with designing, manufacturing and operating automobiles. It is a segment of vehicle engineering which deals with motorcycles, buses, trucks, etc. It includes mechanical, electrical, electronic, software and safety elements.

Question - 2 : -
How will you differentiate between two stroke engine and four stroke engines?

2-stroke piston engine has an intake and an exhaust stroke. All air, fuel, and combustion products must be moved in those 2 strokes. A 4-stroke engine has a separate stroke for moving burned (or burning) and unburned mixtures - intake, compression, expansion, and exhaust. Using 4-stroke results in cleaner emissions at the expense of specific power.

Two stroke: For each explosion in cylinder piston moves downwards and upwards (one complete cycle) (Power stroke and Exhaust stroke).

Four stroke: for each explosion in cylinder piston moves down and upwards twice (two complete cycle) (Intake , compression, power, exhaust stroke.)

Four stroke is highly efficient than two stroke.
But two stroke is powerful than four stroke.

Question - 3 : -
What is the range of engine efficiency in case of two stroke engine?

The two stroke engines have very high range to be compared to the four stroke engines. Because power stroke is generated every two revolution while in four stroke, power stroke is generated every four revolutions.

Question - 4 : -
Definition of Octane number & Cetane number

Octane Number - Octane number is defined as the percentage, by volume, of iso octane in the mixture of iso-octane and h-heptane. It is the measure of rating of SI engine.
Cetane Number - Cetane number is defined as the percentage, by volume, of n-cetane in the mixture of n-cetane and alpha methyl naphthalene. It is the measure of rating of CI engine.

Question - 5 : -
What do you understand by CC of engine?

The meaning of CC is cubic centimeters. It represents the total volume of the engine cylinder. This reflects that the engines with more CC can generate more powers than the other engines. CC can also be related as inversely proportional to the fuel consumption.

Question - 6 : -
If we use gasoline in diesel engine, what will happen?

Adding gasoline to the diesel engine may blast off the engine. Compression ratio of the petrol engine is 6 to 10 and diesel engine is 15 to 22. Thus gasoline will get very highly compressed and might result in blast off engine.

Question - 7 : -
Explain the significance of governor in automobiles?

Governor is an important component of automobile engine. It is used to regulate the main speed of engine during the variations in loads. With the variations in the load, fuel supply has to be maintained. This task is performed by the governor. In the case of high load on the engine, speed decreases, hence fuel supply has to be increased and similarly when load decreases then the fuel supply has to be decreased.

Question - 8 : -
What is the use of hydrogen in automobile?

Low emissions. Essentially no CO or HC in the exhaust as there is no carbon in the fuel. Most exhaust would be H₂O and N₂ Fuel availability. There are a number of different ways of making hydrogen, including electrolysis of water.

Question - 9 : -
What is the use of Natural gas in automobiles?

High octane number makes it very good S.I engine fuel
Low engine emissions. Less aldehydes than with methanol

Question - 10 : -
What is an automotive differential and how does it work?

The automotive differential is designed to drive a pair of wheels while allowing them to rotate at different speeds. In vehicles without a differential, such as karts, both driving wheels are forced to rotate at the same speed, usually on a common axle driven by a simple chain-drive mechanism.