Set 24 - Motor important questions and answers for class 4 exam in India

1. An advantage of aluminium pistons compared to cast iron pistons is:
choose one greater high temperature strength better heat conductivity greater weight per cubic cm increased resistance to wear

2. Which engine component increases air density and helps to improve engine operating efficiency
choose one impeller compressor aftercooler exhaust diffuser

3. An electric heater built into the cylinder water jacket would be used to
choose one raise lube oil viscosity for easier starting in cold weather increase air inlet temperature increase compression ratio increase water temperature for easier starting in cold weather

4. Which is found with both mechanical and hydraulic governors?
choose one direct linkage between the ball head and fuel rack a servomotor a compensating device flyweights

5. Which of the following design features will reduce the possibility of overheating the top compression rings of a cast iron piston?
choose one The top ring is located as close to the piston as possible The inside surface of the piston head is rounded into the ring belt A nickel-bearing insert is cast into the top ring groove A heat dam design is sometimes used in the piston head

6. The purpose of heat dam used in some diesel engine cast iron pistons is to a)concentrate all heat in the piston crown
choose one increase the distance of travel for heat from the crown to the top ring groove concentrate all heat in the piston crown ensure that all heat in the piston crowns is conducted to the top ring )provide a short direct path for heat to flow from the crown to the top ring

7. Valves used in diesel engine fuel oil pressure piping are to be
choose one installed to close against flow solenoid released upon the failure of engine lubrication either of the gate or globe valve type forge constructed under the approval of the Marine Inspector

8. Cast iron pistons used in large propulsion engines are constructed with
choose one no taper whatsoever the skirt being tapered and smaller than the crown the skirt being tapered and larger than the crown the crown being tapered and smaller than the skirt

9. The diameter of a piston is usually less at the crown than at the skirt, in order to
choose one facilitate the installation of piston rings allow for the expansion of the piston during operation prevent crankcase vapors from entering the combustion chamber reduce wearing of the upper cylinder liner

10. Which of the following manufacturing methods is recommended for diesel engine fuel injection line piping?
choose one Cold rolled Electric resistance welded Seamless drawn Straight seam

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