(a) Describe the function of a main engine turbocharger.(5)
(b) Describe how the turbocharger is cooled.(2)
(c) Describe how the turbocharger is lubricated.(3)
(a) Explain why air coolers are fitted after main engine turbo chargers.(6)
(b) Explain the effects of undercooling the charge air on the engine. (4)
With reference to large medium speed diesel engine turbo chargers:
(a) explain why a thrust bearing is needed;(4)
(b) state where the thrust bearing is fitted;(2)
(c) describe how the thrust bearing is lubricated.(4)
With reference to main engine turbo chargers, explain the purpose of EACH of the following:
(a) the volute casing;(3)
(b) the diffuser;(4)
(c) the nozzle ring.(3)
With reference to diesel engine turbocharger construction, explain the purpose of EACH of the following:
(a) labyrinth glands;(3)
(b) diffuser;(3)
(c) inducer;(2)
(d) thrust bearing.(2)
With reference to large medium speed diesel engine turbo chargers:
(a) explain what is meant by the term pulse system;(6)
(b) explain the advantage the pulse system has over the constant pressure system.(4)
With reference to a turbocharged engine fitted with charge air cooler, It is noticed that boost pressure at the inlet manifold is reducing over a period of time:
(a) list FOUR possible causes; stating a simple and economical in service maintenance routine that would rectify EACH(8)
(b) state the effect reduced inlet pressure at full load will have on the engine.(2)
(a) Explain why the air outlet from the turbocharger should be cooled before entering the diesel engine cylinder.(4)
(b) Explain why the charge air cooler has fins attached to its tubes.(2)
(c) State possible reasons why the charge air coolers performance may be reduced.(4)
With reference to air coolers, explain the purpose of EACH of the following:
(a) zinc anodes;(3)
(b) vent cocks;(3)
(c) tube fins.(4)
With reference to poor turbocharger performance:
(a) state FOUR possible causes;(4)
(b) describe the possible indications.(6)
(a) Sketch a cross section through a resilient/flexible mounting for a diesel engine, labelling the MAIN components.(8)
(b) State the special consideration necessary with respect to the engine installation when using the type of mounting in part (a).(2)