单项选择题
A.lubricating B.cooling C.sealing D.cleaning
In some diesel engine designs,（）the injection of cylind...
单项选择题In some diesel engine designs,（）the injection of cylinder oil is timed to impinge when the piston and only impinge on（）
A.is coming upward；cylinder ring belt B.is going downward；piston ring belt C.is coming upward；piston ring belt D.is going downward；cylinder ring belt
（）diesel engines generally have two systems of lubricat...
单项选择题（）diesel engines generally have two systems of lubrication:（）a total loss system feeding and a circulating system lubricating the running gear and cooling the pistons.
A.Large crosshead type；crossheads B.High speed；the cylinders C.Large crosshead type；the cylinders D.Four-stroke；pistons and cylinders
The following options are all the functions of lubricat...
单项选择题The following options are all the functions of lubricating oil except（）
A.removing heat and deposits B.neutralizing acidic products C.lubricating D.improving combustion efficiency
