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Wednesday, 18 February 2015

Interview Questions For Mechanical (Fresher) - Part 3

Trained Engineers - 10:04

Interview Questions For Mechanical (Fresher) - Part 3
Question (21) : Compare Brayton Cycle and Otto Cycle?
Answer :- The heat addition and rejection processes in Otto cycle are of constant volume, whereas in Brayton cycle, they are of constant pressure.
-Otto cycle is the ideal cycle for spark ignition engines.
-Brayton cycle is the ideal cycle for gas power turbines.
Question (22) : What is the purpose of Scrapper Ring?

Answer :-
 Scrap the excess lube oil from the cylinder walls. there by preventing oil from entering combustion zone.
Question (23) : What is DTSI Technology?
Answer :- DTSI stands for Digital Twin Spark Plug Ignition. The vehicles with DTSI Technology use 2 spark plugs which are controlled by digital circuit. It results in efficient combustion of air fuel mixture.
• Digital - Since the spark generation will be initiated by a microchip.
• Twin - Since two spark plugs will be used.
• Spark ignition - Since the ignition will be done via a spark.
Question (24) : How to Find, Ductile-Brittle Transition Temperature in Metals?
Answer :- The point at which the fracture energy passes below a pre-determined point for a standard Impact tests. DBTT is important since, once a material is cooled below the DBTT, it has a much greater tendency to shatter on impact instead of bending or deforming.
Question (25) : What is the importance of Thermodynamics?

Answer :- All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very important for the mechanical engineers.
Question (26) : How a Diesel Engine Works as Generator?
Answer :- Diesel engine is a prime mover, for a generator, pump,and for vehicles etc. generator is connected to engine by shaft. mostly in thermal power plat ,there is an engine is used to drive generator to generate power.

Question (27) : State difference between AnitiFriction Bearing and Journal Bearing?

Answer :-
 Generally, journal bearings have higher friction force, consume higher energy and release more heat, but they have larger contact surface, so normally used in low speed high load applications. In anti friction bearings friction is less. One object just rolls over each other.
Question (28) : What is the difference between Technology and Engineering?
Answer :- Engineering is application of science. Technology shows various methods of Engineering. A bridge can be made by using beams to bear the load,by an arc or by hanging in a cable; all shows different technology but comes under civil engineering and science applied is laws of force/load distribution.
Question (29) : What are the Advantages and Disadvantages of using LPG in Car?

Answer :-  
1. Complete combustion
2. Fuel saving
3. Homogenous combustion
1. As complete combustion is occurring ,more heat liberated,not advised for long journey, engine will be over heated
2. Installation is difficult
3. Reduce engine life efficiency

Question (30) : What is the difference between Speed and Economic Speed?
Answer :- The rated speed tells us about the maximum speed which can be achieved by a vehicle or some other machine but the economical speed means the speed limit at which the machine works efficiently with least consumption of normal bikes(not racing),the max.speed limit shown on speedometer is upto 120 kmph but companies always advice their customers to drive such bikes at around 60 kmph to have maximum mileage.

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