U.S.C.G. Merchant Marine Exam - Motor Plants (1) | 69 Questions and Answers(A+ Solution guide)

The theoretical minimum compression ratio necessary to ensure compression ignition in a direct injection diesel engine is __________. (A) 10:1 (B) 12:1 (C) 16:1 (D) 20:1 - B Modern marine diesel engines equipped with mechanical fuel injection operate on a combustion cycle which is __________. (A) entirely constant volume (B) entirely constant pressure (C) a combination of constant volume and constant pressure (D) a combination of constant temperature and constant pressure - C The power/expansion stroke shown in the illustration is indicated by the diagram numbers __________. Illustration MO-0025 (A) 1 through 3 (B) 1 through 4 (C) 3 through 6(D) 4 through 6 - A The start of fuel oil injection into the cylinder of a four-stroke cycle diesel engine occurs during the __________. (A) intake stroke (B) exhaust stroke (C) power stroke (D) compression stroke -D If the piston stroke in a four-stroke cycle diesel engine is 10 1/2 inches and the speed of rotation of the crankshaft is 720 RPM, what is the average piston speed? (A) 1200 feet/minute (B) 1260 feet/minute (C) 1320 feet/minute (D) 1380 feet/minute - B of 37 Q531 Motor Plants IThird Assistant Engineer Q531 Motor Plants I Illustrations: 21 Which of the following conditions would NOT be considered a valid reason for the diesel engine to operate in the area indicated by letter "B" shown in the illustration? Illustration MO-0126 (A) Operating the vessel against high winds and current (B) Operating with a fouled or damaged propeller (C) Operating the vessel in shallow water (D) Operating with minimal hull drag and under light draft - D The indicator card shown in the illustration is produced with a/an __________. Illustration MO-0108 (A) oscillating drum (B) sliding camshaft (C) rotating drum (D) balanced-diaphragm indicator - C