The booster pump, which supplies diesel oil to（） , should have a possibility of being powered by compressed air or by emergency power.

单项选择题A full-flow 50μm filter is installed ,（） so the injection system components on the main engine are safeguarded.

A.as close to the main engine as possible
B.as close to the main pump as possible
C.just before the fuel valve
D.just before the booster pump

单项选择题The fuel from the bunker tanks must be treated by before entering the service tanks（）, from where the fuel enters（）

A.centrifugal separators; the engine cylinder
B.oily water separators; the engine cylinder
C.oily water separators; the fuel supply system
D.centrifuges; the fuel supply system

单项选择题When the heavy fuel oil is heated to achieve the viscosity of 10-15 cst, may occur.To avoid this, a system is used in most occasions（）

A.boiling and cavitations; low temperature
B.boiling and cavitations; pressurized
C.leaking and boiling; low temperature
D.leaking and boiling; pressurized

单项选择题In order to improve the working conditions of the crosshead bearings, the bearing pressure is made and the peripheral speed is made in later designs（）

A.smaller, higher
B.higher, smaller
C.smaller, smaller
D.higher, higher

单项选择题In order to control thermal stresses, some types of modern engines use pistons with（）

A.heavy wall and intensive cooling
B.heavy wall and no cooling
C.thin wall and no cooling
D.thin wall and intensive cooling