upwards；inwards
upwards；outwards
downwards；inwards
downwards；outwards
第1题：
The sealing rings are in four parts and pressed together around the piston rods by means of _____
A.nuts
B.bolts
C.coil springs
D.stuffing boxes
第2题：
is coming upward；cylinder ring belt
is going downward；piston ring belt
is coming upward；piston ring belt
is going downward；cylinder ring belt
第3题：
Sealing in pump shaft is achieved by means of the ( ).
A.gasket
B.packing
C.o-ring
第4题：
Control the amount of lube oil burned in the combustion chamber
Transmit heat from the piston to the cylinder liner
Prevent damage to ring groove inserts by acting as a heat dam
Dissipate combustion chamber gas pressure by channeling it through the ring gap
第5题：
Ⅰonly
Ⅱ only
both Ⅰ and Ⅱ
neither Ⅰ nor Ⅱ
第6题：
a coil spring
a sealing ring
an oil distributor ring
main seal ring
第7题：
top of the ring groove
cylinder liner oil film
bottom of the ring groove
back of the ring groove
第8题：
Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?
A.Control the amount of lube oil burned in the combustion chamber
B.Transmit heat from the piston to the cylinder liner
C.Prevent damage to ring groove inserts by acting as a heat dam
D.Dissipate combustion chamber gas pressure by channeling it through the ring gap
第9题：
lube oil pumping
rotating rings
gas pressure behind the ring
passage of hot gases
第10题：
insufficient lubrication
improper piston cooling
blow-by
overload operation