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
A.Large crosshead type;crossheads B.High speed;the cylinders C.Large crosshead type;the cylinders D.Four-stroke;pistons and cylinders
A.removing heat and deposits B.neutralizing acidic products C.lubricating D.improving combustion efficiency