Engine Structure Rt flex 50
Wärtsilä RT-fl ex50 engines have a wellproven
type of structure, with a ‘gondola’-type
bedplate surmounted by very rigid, A-shaped
double-walled columns and cylinder block,
all secured by pre-tensioned vertical tie rods.
The whole structure is very sturdy with low
stresses and high stiffness. Both bedplate and
columns are welded fabrications which are
also designed for minimum machining.
A high structural rigidity is of major
importance for the today’s two-stroke engine’s
long stroke. Accordingly the design is based on
extensive stress and deformation calculations
carried out by using a full three-dimensional
fi nite-element computer model for different
column designs to verify the optimum frame
confi guration.
The double-walled column has thick guide
rails for greater rigidity under crosshead shoe
forces. The RT-fl ex supply unit is carried on
supports on one side of the column and the
scavenge air receiver on the other side of the
cylinder jacket. Access to the piston underside
is normally from the supply unit side, but
is also possible from the receiver side of the
engine, to allow for maintenance of the piston
rod gland and also for inspecting piston rings.
The cylinder jacket is a single-piece castiron
cylinder block with a high rigidity. The
cylinder liners are seated in the cylinder block,
and are sufficiently robust to carry the cylinder
covers without requiring a support ring. A light
sleeve is applied to upper part of each liner to
form a water jacket.
The tilting-pad thrust bearing is integrated
in the bedplate. Owing to the use of gear
wheels for the supply unit drive, the thrust
bearing can be very short and very stiff, and
can be carried in a closed, rigid housing.
Wärtsilä RT-fl ex50 engines have a wellproven
type of structure, with a ‘gondola’-type
bedplate surmounted by very rigid, A-shaped
double-walled columns and cylinder block,
all secured by pre-tensioned vertical tie rods.
The whole structure is very sturdy with low
stresses and high stiffness. Both bedplate and
columns are welded fabrications which are
also designed for minimum machining.
A high structural rigidity is of major
importance for the today’s two-stroke engine’s
long stroke. Accordingly the design is based on
extensive stress and deformation calculations
carried out by using a full three-dimensional
fi nite-element computer model for different
column designs to verify the optimum frame
confi guration.
The double-walled column has thick guide
rails for greater rigidity under crosshead shoe
forces. The RT-fl ex supply unit is carried on
supports on one side of the column and the
scavenge air receiver on the other side of the
cylinder jacket. Access to the piston underside
is normally from the supply unit side, but
is also possible from the receiver side of the
engine, to allow for maintenance of the piston
rod gland and also for inspecting piston rings.
The cylinder jacket is a single-piece castiron
cylinder block with a high rigidity. The
cylinder liners are seated in the cylinder block,
and are sufficiently robust to carry the cylinder
covers without requiring a support ring. A light
sleeve is applied to upper part of each liner to
form a water jacket.
The tilting-pad thrust bearing is integrated
in the bedplate. Owing to the use of gear
wheels for the supply unit drive, the thrust
bearing can be very short and very stiff, and
can be carried in a closed, rigid housing.
