MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)What happens if gasoline is used in a Diesel engine?Diesel engine will work ?

Ans.:No, It will not work,as the Compression ratio of Petrol engine is 6 to 10 & that of Diesel engine is 15 to 22. Thus on such high compression, gasoline gets highly compressed & it may blast.

2.)Why different types of sound are produced in different bikes though they say run on SI engine?

Ans:Engine specifications are different in different manufactures like as Bore Diameter(CC), Ignition timing.Also the exhaust passage take more responsible for sound.

3.)1 hp how much watt?

Ans: 746.2Watt

4.)Explain Bicycle rear wheel Sprocket working?

Ans:Rear wheel sprocket works under the principle of ratchet and pawl.

Spark Plug

 

A spark plug (sometimes in British English a sparking plug, colloquially a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark, while containing combustion pressure within the engine. A spark plug has a metal threaded shell, electrically isolated from a central electrode by a porcelain insulator. The central electrode, which may contain a resistor, is connected by a heavily insulated wire to the output terminal of an ignition coil or magneto. The spark plug's metal shell is screwed into the engine's cylinder head and thus electrically grounded. The central electrode protrudes through the porcelain insulator into the combustion chamber, forming one or more spark gaps between the inner end of the central electrode and usually one or more protuberances or structures attached to the inner end of the threaded shell and designated the "side", "earth", or "ground" electrode(s).
Spark plugs may also be used for other purposes; in Saab Direct Ignition when they are not firing, spark plugs are used to measure ionization in the cylinders - this ionic current measurement is used to replace the ordinary cam phase sensor, knock sensor and misfire measurement function.[citation needed] Spark plugs may also be used in other applications such as furnaces wherein a combustible fuel/air mixture must be ignited. In this case, they are sometimes referred to as flame igniters.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)What is the name given to process of removing non condensables in steam and other vapor cycles ?

Ans: Deaeration process.

2.). We often come across use of jet pumps in process industry ? What is the reason for this ?

Ans: Jet pumps are easy to maintain and can be used to transport gases, liquids and mixtures of both.

3.)When it can be said that a fluid is Newtonian ?

Ans: When the shear stress is directly proportional to velocity gradient.

4.)Out of 2 stroke SI engine, 4 stroke SI engine, and 4 stroke CI engine, how the brake thermal efficiency behaves if these are to be used for road vehicles ?

Ans: 4 stroke CI engine has highest brake thermal efficiency followed by 4 stroke SI engine and the 2 stroke SI has lowest brake thermal efficiency

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)What is operating pressure?

Ans.-Operating pressure is the standard level of pressure a system operates under, usually within a fairly narrow range of tolerances.

2.)Explain Otto cycle.

Ans.-An Otto cycle is an idealized thermodynamic cycle which describes the functioning of a typical spark ignition reciprocating piston engine,the thermodynamic cycle most commonly found in automobile engines.he Otto cycle consists of adiabatic compression, heat addition at constant volume, adiabatic expansion, and rejection of heat at constant volume.

3.)What is annealing?

Ans.-The steady heating of a metal at a certain temperature above the recrystallization phase followed by a gradual cooling process is called annealing.

4.)What is Carburizing?

Ans.-A surface hardening method that heats metal within a carbon-rich environment to increase carbon levels on the metal surface for added hardness is called Carburizing.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)Why excess air is required to burn a fuel completely ?

Ans: Excess air is required to ensure adequate mixing of fuel and air, avoid smoke, minimize slagging in coal burning, and to ensure maximum steam output.

2.)At what pressure and temperature the density of water and steam is same ?

Ans: At 225 kg/cm2 and 74.6° C.

3.)What is meant by quality of steam ?

Ans: It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.

4.) Why the efficiency of superheat Rankine cycle is higher than that of simple Rankine cycle?

Ans: Because the mean temperature of heat addition is higher for superheat cycle.