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4) Cylinder Head Gasket
(1) Features
Sealing the cylinder gas pressure - Peak pressure: 190 bar
Minimizing the distortion of engine structure (cylinder head, block): profile stopper, backland stopper
Material: MLS (Multi Layer Steel), Gasket (3 layers)
Thickness of gasket: 3 types (1.2 /1.3 /1.4 mm) 1.
2.
3.
4.
(2) Thickness of cylinder head gasket
There are three types of gasket to managing the compression ratio.
Piston protrusion ▶
Piston protrusion Thickness
0.475 to 0.540 mm 1.2t
0.541 to 0.649 mm 1.3t
0.650 to 0.745 mm 1.4t
Thickness marking
Ex: 1.3t
Page 189 of 796
02-30
1) Chain Drive
(1) Overview
The drive chain is single chain drive system with simple design and variable performance, and it utilizes
the hydraulic tensioner to reduce the wave impact generated by the chain. This chain is light weight and
has high durability through single bush chain. Shoulder bolts are used for better NHV.
7. CHAIN AND GEAR DRIVE SYSTEM
D20DTR engine uses single stage chain drive system. Timing chain drives the exhaust side and gear
drive the intake side. Timing chain is single bush type. Upper chain drives HP pump connected to
intake Camshaft by driving exhaust cam shift sprocke, and lower chain drives oil pump to lubricate the
engine.
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02-32
2) Timing Chain and Gear
(1) Timing chain
Simple layout: optimized timing, enhanced
NVH
Single stage layout: minimized chain load
The brass link on crankshaft is at symmetric
position of that on camshaft. -
-
-
Chain upper bush
- Single bush type (112 EA)
Chain lower bush
- Single bush type (60 EA)
(2) Tensioner
Tensioner adjusts the chain tension to keep it tight during engine running. This reduces the wear in
guide rail and spoke.
Operating principle
- Use the spring tension in tensioner and hydraulic pressure
Tensioner type
- Compensation and impact absorbing
Static and dynamic force
- Spring + Hydraulic pressure 1.
2.
3.
Plunger
HousingSpring
Check valve
Hydraulic tensioner assembly ▶
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02-36
Oil pan sassembly
8. OIL PAN
The oil pan in D20DTR engine improves the NVH. Especially, the oil draining is much easier than
before.
Components ▶
Page 196 of 796
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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 -
-
-
2) Layout
Spring guide
Drive plate
Primary cover
Primary flywheel
Internal/external ringSecondary flywheel
Ring gear
Page 197 of 796
02-38
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 -
-
-
-
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) -
-
-
-
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 ▶
Page 200 of 796
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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