Q- To reduce sulphur corrosion of main engine components
a. Run at normal load
b. Atomizing pressure of fuel
c. Rotor in exhaust valve
d. Fuel feed rate in purifier and purifier in series
Q- which of the following statement is true if the oil temperature is allowed to become excessively high in the heater?
a) excessive temperature will increase oil viscosity that results to poor combustion
b) excessive temperature will cause the oil to crystallize resulting in pulsating fires
c) the fuel will carbonize and its heating will be reduced.
d) the fuel will ignite even it has not reached point of ignition.
Q-Which of the following statements correctly describes the phenomenon of surging in a 2-stroke crosshead type engine?
A.Due to sudden increase in engine load the exhaust gases may flow back through scavenge ports causing surge
B.Due to sudden decrease in engine load the turbocharger pressure ratio drops . This causes high pressure downstream of T/C in scavenge trunk causing flow reversal of scavenge air
C.Due to sudden increase in engine load , the T/C turbine rpm may increase suddenly increasing the compressor pressure ratio to surge
D.Due to sudden decrease in engine load , the turbocharger may stall as the higher pressure downstream in exhaust system may cause reversal of flow of exhaust gases
Q- Exhaust grouping in main engine is for-
1 Better starting
2 No need for auxiliary blowers
3 Pure prime
4 Cost Saving
Answer-Both 1 and 2 but most appropriate is 2
Q- Exhaust Grouping is required in case of ______________ turbocharging in order to _____________________
A.Constant pressure , prevents shockwave generation
B.Pulse pressure , prevent interference with scavenging of other cylinders
C.Constant pressure, prevent interference with scavenging of other cylinders
D.Pulse pressure , prevents shockwave generation
Q- The temperature, at which a fuel will start to burn under given conditions, is called its, ignition temperature. This temperature varies greatly with
(a) Composition of the air-fuel mixture.
(b) Amount of excess air.
(c) Size, shape and temperature of the compression space.
(d) All the above