2012 SSANGYONG RODIUS Service Manual

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9. DUAL MASS FLYWHEEL (DMF) & DRIVE PLATE
1) Overview
Flywheel is installed on crankshaft. When
starting the engine, this functions as follows:
Reducing the irregular speed of crankshaft
due to unbalanced combustion ->
Improving the power train NVH, Improving
the driving performance
Reducing the clutch noise by using ball
bearing
Improving the durability of DMF by using
strong arch spring -
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2) Layout
Spring guide
Drive plate
Primary cover
Primary flywheel
Internal/external ringSecondary flywheel
Ring gear

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Torque change curve of engine and drive shaft
Compression stroke Combustion stroke
Small changes from engine (k):
Damper increases the torque changes to clutchLarge changes from engine (j):
Damper decreases the torque changes to
transaxle by absorbing the impact
3) Operation
Compensating the irregular operation of engine: The secondary flywheel operates almost
evenly so does not cause gear noises
The mass of the primary flywheel is less than conventional flywheel so the engine irregularity
increases more (less pulsation absorbing effect).
Transaxle protection function: Reduces the torsional vibration to powertrain (transaxle) by
reducing the irregularity of engine. -
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4) Features
Reduced vibration noise from the powertrain by blocking the torsional vibrations
Enhanced vehicle silence and riding comforts: reduced engine torque fluctuation
Reduced shifting shocks
Smooth acceleration and deceleration -
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5) Advantages
Improved torque response by using 3-stage type spring: Strengthens the torque response in all
ranges (low, medium, and high speed) by applying respective spring constant at each range.
Stable revolution of the primary and secondary wheel by using planetary gear: Works as
auxiliary damper against spring changes
Less heat generation due to no direct friction against spring surface: Plastic material is covered
on the spring outer surface
Increased durability by using plastic bushing (extends the lifetime of grease) -
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6) Drive Plate
Drive plate receives the power from the start motor when starting the engine. With this, the drive
plate initially drives the power train system. And, it is connected to the torque converter to transfer
the engine torque to the power train system.
Trigger ring
Drive plate
Components ▶

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10. PISTON/CRANKSHAFT/CYLINDER BLOCK
The crankshaft and the cylinder block convert the compression pressure to the rotating energy.
Components ▶
Cylinder block
Piston
Connecting rod
Crankshaft

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1) Piston
(1) Overview
Piston assembly contains piston, #1 ring, #2
ring, oil ring, piston pin and snap ring. The
expansion energy from engine is transferred
to the crankshaft through connecting rod to
convert the linear movement to rotating
energy.
(2) Layout
#1 ring
Oil ring
Snap ring
#2 ring
Material:
B2+
Skirt coating:
MoS2
Piston cooling gallery
for connecting rod
Wide bawl type (CR 16.5)
Cooling jet

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(3) Functions
Piston transfers the combustion energy from engine to connecting rod. Especially in the direct
injection engine such as D20DTF, it provides the combustion space and largely effects to the
engine performance and exhaust gas.
Piston ring
#1 ring (Top ring) : Prevents the high pressurized combustion gas from leaking into crank
chamber, and prevents the engine oil getting into combustion chamber.
#2 ring: Scrapes the engine oil on the cylinder bore, and prevents the leaked combustion gas
from #1 ring from leaking into the crank chamber.
Oil ring: Scrapes the engine oil on the cylinder bore.
Piston pin
Connects the piston the connecting rod, and transfers the linear movement of piston to
connecting rod to convert it to rotating energy
Snap pin
Locks the piston pin. ▶
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(4) Assembling the piston
Install the piston rings with the "Y" mark on
the ring facing upwards.
Position the end gap of #1 ring at 180˚
away from the end gap of #1 ring.
Position the end gap of oil ring at 180˚
away from the end gap of coil spring, and
position the end gap of oil ring at 90˚ away
from the end gap of #2 ring. 1.
2.
3.

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Selecting piston oversize
Top of piston Top of cylinder block
EnginePiston Cylinder bore
Part NO Marking NO.-
D20DTF 671 030 06 17 - -
671 037 07 01 A A
671 037 08 01 X X
671 037 09 01 B B
671 037 10 01 +5 -
671 037 11 01 +10 -

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2) Connecting Rod
(1) Overview
Connecting rod converts the reciprocating movement of piston to the rotating movement of
crankshaft. The big end is connected to connecting rod bearing and the crank pin journal, and the
small end is connected to the piston pin.
(2) Components
Connecting rod cap bolt
Connecting rod upper bearing
Connecting rod
Piston pin bush
Connecting lower bearing
Connecting rod cap