Automobile Engineering interview questions and answers - part 2


Automobile Engineering interview questions and answers - part 2

Part 1   Part 2   Part 3   Part 4   Part 5   Part 6

What is BHP? How can you measure BHP?

BHP is ‘Brake Horsepower’. It reflects the powerfulness of the brakes of the vehicles. BHP stands for how much power will be required to make the engine stop working i.e. to stop the rotation of the engine.
BHP = 2 times pi times torque times revolutions; all this divided by 550.
Pi is 3.1416 and torque is in pounds-feet, and revolutions are revs per second

What will happen if someone adds oil to the fuel of four stroke bike engine?

This will result in damaging of the engine faster. Adding oil will lead to the higher wear and tear of the cylinder liner, piston and damage to the piston. It will lead to abnormal combustion and knocking and detonation. Dark smoke and abnormal sounds will be generated by the engine. One should not mix oil with the fuel of four stroke engine.

How will you differentiate between two stroke engine and four stroke engine?

In case of two stroke engine, rotation of crank shaft will be power stroke for every two rotations. During compression stroke, fuel will flow towards the crank case(suction) and during power stroke, exhaust will emit the burnt fuel through the transfer ports.
While in case of four stroke engine, rotation of crank shaft will be power stroke for every four rotation. Moreover, suction compression power and exhaust strokes are separate as there will be inlet and exhaust valves.

What is the size of the recommended compressor CFM? Where it can be used?

It is generally used in spray painting of very small areas. It can be used where painting with brush is very difficult. thus to improve the rate of painting the spray painting is used as this method is very fast and efficient. Usually reciprocating compressors are used but size depends on requirements.

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.

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.

What is back compressor in engines?

Back compression means the compression capability of the engine. An diesel engine can compress at the ratio of 14:1 to as high as 25:1. Thus the higher compression leads to better efficiency of the engine. Thick black smoke is emitted when the engine’s compression is reduced which leads to the deformed ead-gasket lead into crankcase.

How air conditioners work in cars?

Air conditioners are based on the principles of evaporation and condensation and then compression and expansion. The hot air of the car is removed by the process of evaporation and then the condensation of the evaporated air takes places which is then further compressed by the compressor and then finally expanded to us in the form of cold breeze. Somehow, Air conditioning reduces the average of the car, as the energy is required to remove the hot air and then compression and expansion.

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Discussion Board
What will happen if someone adds oil to the fuel of four stroke bike engine?

The answer is correct. Still if the oil quantity is less then piston movement will be smooth due to this oil. But it will create little carbon on top of piston.

Harish Kamath 02-27-2017 02:20 AM

Working of A/C in car (mistake)

The sequence is 1.Evaporation 2.Compression 3.Condensation 4.Expansion

Pavan 01-27-2017 05:44 AM

wrong answer

there is mistake in two stroke & fore stroke engine answer

In two stroke engine we get power stroke per revolution of crank shaft
in four stroke engine we get power stroke per two revolution of crank shaft

bhavini bijlani 02-7-2016 01:28 AM

hp & bhp

in automobile h.p means actual power producing by an engine while bhp (brake horse power) it denote the ultimate result of the power of hp. which reflect on wheel of the vehicle.

Bishwajit kumar gomo dhanbad 08-1-2015 05:58 AM


i think BHP is Output power of the engine ...which measured at output shaft ,,not the power of stop the engine....because its depend upon break efficiency to stop vehicle..if u want to stop d engine just turn off the ignition key ;)

Harsh Chovatiya 03-18-2015 02:51 PM

four stroke vs two stroke engines comparison is wrong

In two stroke engines the power stroke ll complete for one rotation of crank whereas for two rotations the power stroke complete in four stroke engines

Ayodya ganapathi 11-24-2014 01:11 PM

the explanation for powergeneration for 4stokee vs 2 stroke is wrong

power generates in two stroke at each revolution of crank, where as in four stroke its 2 revolutions

prashanth 12-4-2013 03:17 AM


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