單項選擇題If a cam-controlled engine has a normal injection pressure at rated speed,the injection pressure will be（）at slow speed.

A.a little lower
B.a little higher
C.too low
D.exactly the same


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1.單項選擇題The main purpose of changing main engine to electronic controlled is not to（）

A.control fuel injection time more precisely
B.control fuel injection rate more precisely
C.meet the environmental requirements
D.meet high engine speed requirements

2.單項選擇題To meet the market requirements, a marine diesel engine should not be of（）

A.big size
B.fuel economy
C.low speed
D.high power

3.單項選擇題The common rail engines show great advantages in combustion especially（）.

A.at high speed and full load
B.at low speed and part load
C.when heavy fuel oil is used at sea
D.when the ships run long distance

4.單項選擇題A common rail engine has only one or two high pressure pumps in operation at the same（）time, and the injection into each cylinder.

A.can’t be controlled very precisely
B.can’t be controlled as flexibly as the separate pump system
C.can be controlled as flexibly as the separate pump system
D.can be controlled more precisely and flexibly

5.單項選擇題（）uses one or two high pressure pumps for all the cylinders with one more standby, while（）have a separate high-pressure pump for each cylinder.

A.A common rail engine；conventional engines
B.A conventional engine；common rail engines
C.A marine diesel engine；most other engines
D.A two-stroke engine；four-stroke engines