In a medium speed diesel engine, a trunk type piston may be cooled by（） Ⅰ.oil circulation though passages in the piston crown Ⅱ.heat transfer through piston rings and liner wall

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  A . decrease until the engine speed increases B . increase as the load increases C . decrease as the load D . increases remain unchanged

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• The main function of tie rods in the construction of large, low speed diesel engines is to（）.

  A . stiffen the bedplate in way of the main bearings to increase the engines longitudinal strength B . accept most of the tensile loading that results from the firing forces developed during operation C . mount the engine frame securely to the hull to prevent shaft coupling misalignment D . connect the crosshead solidly to the piston rod

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• An over-speed trip stops a diesel engine when the engine （）

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• On a medium-speed main propulsion diesel engine, the crank-pin or crank journal bearings receive lubricating oil from （）.

  A . a spindle lubricator B . an oil jet C . internal splashing D . drilled passages in the crankshaft

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• On a turbo-charged, medium-speed diesel engine, which of the following problems is an indication of a restricted air intake passage?（）

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• There is a vessel in position 120.0E 24.5N on course 120 degrees and speed 12.5 knots（）is not complying with traffic regulations.

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• Critical speed in diesel engines occurs when engine torque pulsations become （）

  A . opposed to the crankshaft rocking couple B . resonant with the crankshaft natural frequency C . critical fore and aft crankshaft vibrations D . horizontal whipping motions of the crankshaft

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• An increase in load on a diesel engine results in （） of speed of the crankshaft.

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• The reason why more and more of the large merchant vessels are being powered by medium-speed diesel engines is （）.

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