The Cylinder Liner of Diesel Engines

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The Cylinder Liner
(Diesel Engines)
Source: MAN B&W

Cylinder Liner
• The function of cylinder liner is to form part of
the combustion chamber which is
compression and combust...

•The liner can be manufactured using a superior material to the
cylinder block. While the cylinder block is made from a gr...

Cylinder Liner - Types
• Wet liners – usually used in medium
and slow speed engines and normally
cooling by water
• Dry li...

3 –PIECES LINER (DOXFORD’P’)

EXHAUST BELT
EXHAUST PORTS
UPPER LUBRICATION
LOWER LUBRICATION
SCAVENGE PORTS
COMBUSTION BELT
UPPER LINER
LOWER LINER
STEE...

CYLINDER LUBRICATION OIL 8 POINTS
CYLINDER LUBRICATION OIL 2 POINTS
WAVE JOINT
LOWER
UNCOOLED
PART BOLTED
TO JACKET
UPPER ...

ANGLED C/W
DRILLINGS
DRILLING PASSES CLOSE TO
LINER SURFACE
BORE COOLING
VIEW
C/W OUT TO CYL HEAD
GROUND FACE
SECOND ADDIT...

Stresses on liners
• Mechanical stress – pressure
• Thermal stress - temperature

Mechanical stress
• In supercharged engines, maximum
firing pressure is about 90 – 100 Bar
(non supercharged is about 75-8...

• HOOP STRESS, h = P x D
WHERE, P = GAS PRESSURE
D = LINER DIAMETER
t = LINER THICKNESS
• Thus hoop stress will increase i...

THERMAL STRESS
• Resistance to heat flow through liner
metal produces a temperature gradient
across liner hence, the inner...

Liner-Stresses
• Thicker liner will increase temperature
gradient hence thermal stress but on
the other hand, thicker line...

Estimated temperature in liner
- Next to liner wall
500oC
- On liner wall 140oC
due to oil film, carbon
deposits and stagn...

Combination of stresses
(plain liner)
METAL THICKNESS
THERMAL STRESS
HOOP or MECHANICAL STRESS
OPTIMUM
METAL
THICKNESS

Liner-temperatures
• The Liner will get tend to get very hot
during engine operation as the heat
energy from the burning f...

Liner-Temperatures & Cooling
• Cylinder liners from older lower
powered engines had a uniform wall
thickness and the cooli...

• To increase the power of the engine for a
given number of cylinders, either the
efficiency of the engine must be increas...

Liner-Temperatures
• If the thickness of the material is
increased, then it stands to reason that
the working surface of t...

Liner-Temperatures
• The solution is to bring the cooling
water closer to the liner wall, and one
method of doing this wit...

TANGENTIAL BORE COOLING

TANGENTIAL BORE
COOLING
• Holes are bored from the underside of
the flange formed by the increase in
liner diameter. The h...

Liner-Bore Cooling
• On some large bore, long stroke
engines it was found that the
undercooling further down the liner was...

Liner-Cooling
• This burns in the oxygen and the products
combine with the water to form sulphuric acid.
If this condenses...

Cylinder liner-Loads
• The inside surface is subjected to the rubbing
action of the piston rings as the piston is
moving r...

Liner-Lubrication
• The oil is of a high alkalinity which
combats the acid attack from the
sulphur in the fuel. The latest...

4 stroke Cylinder Liner
• The cylinder liner is cast separately
from the main cylinder frame for the
same reasons as given...

• Modern liners employ bore cooling at the top
of the liner where the pressure stress is high
and therefore the liner wall...

4S Liners
• On the example shown, the lubricator
drillings are bored from the bottom of
the liner circumferentially around...

Sulzer ZA40 Liner (vee engine; The straight engine is similar)
Other engines may utilise axial drillings as in a two strok...

Cylinder Liners-Cooling Water
• Where the cooling water space is
formed between the engine frame and
the jacket, there is ...

MAN-B&W L58/64 Liner

Cylinder Liners-Cooling Water
• Modern engines tend not to use this
space for cooling water. Instead a
separate water jack...

Cylinder Liner-AP Ring
• Note that the liner opposite is fitted with a
fireband. This is sometimes known as an
antipolishi...

Liner-Materials
• Cast iron is used for the following reason:
- Castibility is good for intricate shapes
- Good wear resis...

MATERIAL
• Nodular or spheroidal cast iron is used for
the following reason:
- tougher
- More resistance to crack formatio...

MATERIAL
• Alloy element
- Specify alloying elements namely
nickel, chromium, copper or
molybdenum – wear resistance to
co...

MATERIAL
• For large bore cylinder liners
generally the cast iron contains:
Carbon - 3.00% Silicon -
0.70%
Manganese - 1.0...

Manufacture
• Two methods
- Sand casting
- Centrifugal casting

Liners-Manufacture
• After casting, liners are rough- machined and
hydraulically pressure tested approximately 7
Bar
• Por...

Surface finish treatment
• Normally used an electrolytic deposition
of hard chrome sometime nickel
• Chrome layer is appro...

Advantages:
• Hard surface and improve wear-
resistance, corrosion resistance,
uniform surface finish
Disadvantages
• Expa...

Sand casting
• Better wearing properties due to better
grain flow produced in cast material
• Better graphitisation, thus ...

Centrifugal casting
• Stronger liner
• Homogeneous in structure
• Poor wearing quality (fast cooling rate)
• Normally used...

Porosity manufactured
• The plated cylinder liner is immersed
into a special bath and the current (for
electroplating) is ...

Liner fault - crack
1 Crack across liner flange due to uneven or excessive
tightening of cylinder head studs
2 Hoop stress...

1
2
3
4
5
6

Cylinder liner wear
There are three main cause of
damage to
the liner material;
• Abrasion-caused by solid
particles break...

Abrasion
• Hard particles combined with cylinder
lubricant to form a light abrasive paste
causing liner wear
• In crosshea...

Liner Wear
• Source of hard particles can originate
from
- Air borne dirt,
- Ash in fuel,
- Carbon from combustion
- Pisto...

Air borne dirt
• Dirty air filter
• Dirty scavenge ports which is should be
keep degree of dirtiness to minimum
• Scavenge...

Ash in fuel
• Fuel consists of vanadium, sodium silica
and scale (iron rust) which cannot be
avoided, however it can be re...

Carbon from combustion
• Combustion can never be perfect to
form a hard carbon particles
• Means that if bad combustion oc...

Piston rings wear
• Produces wear dust from rubbing and
this increases wear of both liner and
rings itself
• Therefore sho...

Corrosion
• Marine fuel contain sulphur to form
sulphur dioxide and sulphur trioxide
when the fuel burns as shown:
SO2 + H...

Pressure(bar)
H2SO4dewpointtemperatureoC)
RELATION BETWEEN H2SO4 DEWPOINT
TEMPERATURE & FUEL SULPHUR CONTENT AT
DIFFERENT ...

Liner wear
• The dew point of the above acid is
around 110oC to 180oC depending
upon concentration, hence acid is
always p...

Remedies of corrosion
• Used alkaline oil for cylinder lubrication
• Control condensation in air cooler
• Keep cooling wat...

Scuffing or friction
• This is occur when lubricant failed to
separate rings and liner surfaces
efficiently and subsequent...

Liner Wear-Scuffing
• Too smooth liner surface resulting in too
little lube oil retention
• Water on the liner surface rep...

Liner wear pattern
• Maximum normal liner wear occurs at top of
the liner, in port-starboard direction and
around scavenge...

– Movement of ship maximum in port- starboard
direction than forward-aft direction (thus causing
more wear here)
– High te...

CLOVERLEAFING
• Alkali in cylinder oil is used to neutralize acid.
• For fuel with 4-5% sulphur -cylinder oil with TBN
(To...

Measured by
profilograph
an instrument
Lube oil Lube oil
Lube oil
Lube oil
Wear due to
excessive alkalinity
in cylinder oi...

Liner wear-TBN
• If TBN use is more, surfaces near quills
will get excessive alkalinity leading to
hard calcium compounds ...

Liner Wear-TBN
• If TBN used is less, surfaces near quills
will have minimum wear but surfaces
furthest from quills will b...

MICROSEIZURE – OIL FILM
RING
LINER
WALL
Asperities meet
RING
LINER
WALL
RING
LINER
WALL
Frictional heat and
welding
Tearin...

OIL - WEDGE
LINER
WALL
LINER
WALL
PISTON
SKIRT PISTON
SKIRT
OIL
FILM
OIL
FILM
OIL –
WEDGE
(1:150
TAPPER)

WEAR RATE
Cyl No Date
Date fitted Date of last
gauging
Total hours Hours since
last gauging
Position Forward and After Por...

Liner wear-Analysis
• Wear rates vary, but as a general rule, for a
large bore engine a wear rate of 0.05 -
0.1mm/1000 hou...

Gauging a Liner

Wear rate
• It is related to time in order to put these
figures into useful form of comparison,
in the form of diameter in...

Liner Wear-Analysis
• Wear rate since new :
Total increase in O
Total running hours since new
X 1000=
= mm/1000 hrs

Maxi. Liner wear rate mm/1000
RUNNING-IN
PERIOD
GRAUDALWEAR
STARTS
WEAR RATE INCREASES
DUE TO WORN RINGS
AND LINERS
MAXIMU...

Causes of excessive wear
• Improper running in – smoothing and geometry
• Misalignment of piston or distortion of cylinder...

DETAIL of SEALING RINGS
• Depth of groove = 0.7 to 0.8d where “d” is diameter
of rings section. This is because the sealin...

DG
Di
d
0.7 to 0.8d
Di = 0.98 DG

Cylinder liner lubrication

Cylinder lubrication
•Because the cylinder is separate from the
crankcase there is no splash lubrication as on a
trunk pis...

LUBRICATOR QUILLS
DISTRIBUTOR
DISTRIBUTOR
CYLINDER OIL SUPPLY
REGULATING VALVE
CYLINDER OIL PUMP

PURPOSE CYLINDER
LUBRICATION
• Reduce friction between liner and ring – scuffing
• Assist in sealing of combustion gas – b...

TO CYLINDER
LUBRICATOR
QUILLS
LUBRICATOR QUILL OR
INJECTOR
CYLINDER
LINER
HYDRAULIC
PLUNGER ROTATING
RATCHET
ROTATING DIST...

FILLING
FILTER
GAUGE
GLASS
CAM (POSITION
ADJUSTABLE)
CAMSHAFT
OIL IN
DUAL SUCTION
VALVE
FLUSHING
TRIGGER
NUT
QUANTITY
REGU...

NON-RETURN
VALVE
OIL INLET
FILLING PIN
RUBBER PACKING
JOINT PACKING
CYLINDER
JACKET
COOLING
WATER
SPACE
COOLING
WATER
SPAC...

CYLINDER
LINER
NON-RETURN
VALVE
LUBRICATOR
QUILL
ACCUMULATOR
FLOW CONTROLLER
CYLINDER LUBRICATING PUMP
OIL QUANTITY ADJUST...

NEW TYPE SULZER RND-M LUBRICATOR QUILL
CYLINDER
LINER
COOLING
WATER
SPACE
CYLINDER
JACKET
FILLING PIN
JOINT PACKING
ACCUMU...

ACCUMULATOR operation
• Through pipe oil is supplied by the cylinder
lubricating pump (at about every 10 – 15
engine turns...

• If the pressure at the delivery point drops
below the accumulating pressure, the oil will
then flow through the upward s...

1
1
2
2
3
3
4
4
56
PRESSURE (BAR)
40
30
20
10
0
BDC TDC BDC90o 270o
CRANK ANGLE
LUBRICATING QUILL
CYLINDER LINER
PISTON
CO...

• In the range of BDC, between the position 5 +
6 and in the range of TDC, between the
position 2 + 3 the pressure in the ...

• Between positions 6 + 2 as well as 3 + 5 the
pressure is higher at the lubricating point than
in the lubricating quill. ...

POSITION OF CYLINDER
LUBRICATORS
• Not to be near the ports – oil can be scraped
and blown away
• Not to be situated too n...

A
B
C
A
B + C
C
Oil film thickness Hmin
Hmin
V ring
A C B+C
Oil refreshing rate
near TDC
Multilevel
lubrication
B
MULTILEV...

Difficulty on achieving
• Piston direction changes every stroke
• In 2-stroke engine, no non-working stroke
available for ...

Difficulty in Timing
• Piston speed may be high (approximately 2o of crank angle only)-
slow movement will destroy oil wed...

Gauging a cylinder liner

Liner Gauging
• Gauging a liner is carried out for two reasons:
To establish the wear rate of the liner, and to
predict if...

Source: www.marinediesels.info

Liner Gauging
• Because of the action of the piston rings, the
varying gas pressure and temperature in the
cylinder, the w...

Liner Gauging
• Because of these factors wear at the top of a
liner increases to a maximum a few
centimetres below the pos...

Liner Gauging
• A liner is gauged by measuring the diameter
of the liner at fixed points down its length. It is
measured f...

Gauging a liner on a large bore RTA engine.
Source: www.marinediesels.info

Liner Gauging
• Measurements are taken at more frequent
intervals at the top of the liner where wear
rate is expected to b...

Liner Gauging
• The readings can be recorded in tabular
form, and from the data obtained the
wear rate/1000 hours can be c...

Cylinder Number: 1
Nominal Dia: 840mm
Total Running hours:
60000
Running hours since last calibration:
15000
Gauging
point...

Replacing cylinder liner
Diesel Engine

The photograph above shows clearly the evidence
of the leaking liner. The cooling water has
evaporated leaving white depos...

• The oil mist detector had activated during a
day at sea and the engine had shut down
automatically due to high oil mist ...

Liner Replacement
• The engine was isolated from main cooling
water systems and drained, the compressed
air system was iso...

Liner Replacement
• The cylinder head and the piston were
removed. The cylinder lubrication pipes
at the bottom of the cyl...

Liner Replacement
• The liner must be jacked off its seating
using a hydraulic jack. In the case of the
ZA40 the jacking d...

After attaching the jacking device to the bottom end bearing the
bearing was turned through 90° and the crankpin turned to...

The liner lifting tool was
then bolted on to the top of
the cylinder liner and hooked
up to the engine room crane.
The lin...

Liner Replacement
 The new assemblies were inspected prior to
fitting.
 While the liner was removed from the engine,
the...

Fig: View looking down through engine frame with cylinder liner
removed.
Note: Although this is a ZA40 engine it is not th...

 The new liner was cleaned,
inspected and gauged to ensure
it was within limits specified by
Wartsila.
 Landing and seal...

Liner Replacement
 The liner was withdrawn and heat resistant Viton O
rings fitted which were well lubricated with engine...

 The running gear was reassembled, fitting new piston
rings.
 Once the cylinder running gear was all in place, the
engin...

 The ammeter on the turning gear panel is monitored so
that if a partial seizure was to occur, the current drawn by
the m...

 Once the engine was ready for starting the normal
routine for checking the engine was followed:
- After a very short run...

References:
1. www.marinediesels.info
2. The Running and Maintenance of Marine Machinery
– Cowley
3. Reeds Marine Engineer...

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