Diesel Engine Cylinder Liner Study

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CYLINDER LINERSMDELubrication Wear

• MICE II
• PPT - 6
• S K Mukherjee,
• Faculty IMU Kolkata Campus.

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CYL LINERSLubrication

• Why Liners (2-St 4-St) need lubrication
• To separate sliding surfaces with an oil film.
• To form an effective seal between ring liner.
• To neutralize acidic combustion products.
• To soften carbon deposits reduce abrasion.
• To clean comb deposits in grooves walls.
• To cool hot surfaces and avoid burning.

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CYLINDER LINERSlubrication

• .

• General requirements of Cyl oil
• Must have required Alkalinity, (Base Nr.)
• Must withstand temperature variations.
• Requirement of higher viscosity (SAE-50)
• Must have detergency.
• Must be able to resist Oxidation.
• Base Nr-70 means 70mg alkali per gm of oil.
  The alkali is usually KOH or CaCO3

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CYL LINERS.wear limits

• Dependant on Manufacturers recommendations.Limitat
  ions to liner wear (2-st Engines)
• Wear down 0.6 0.8 of Dia. (ext Max 1)
• Admissible wear rate 0.05-0.15mm/1000Hr. (varies
  with dia, see chart)
• Life of liner 6 to 7 years _at_ 6000hrs/Year.
• Usually 40K running hours. (ext max 50K)

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Cyl Lub.Liner WEAR limits.
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Cylinder Lubrication....process

• Has critical effect on good engine operation.
• Significant bearing on oil consumption
  operating costs.
• Dependant on
• i) Load, and sulphur content in the fuel oil.
• ii) Bore, Stroke, piston speed, cyl temp, type
  
• of engine, location of quills, type of
  fuel.
• iii) ideally delivered near piston reversal
  points.
• iv) Injected between top two rings during
• upward stroke of the piston

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Cylinder Lubrication.timing
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CYL Lubrquill location pts.

• Position of quills delivery holes location
• Not to be located at very high temp zone lest the
  oil burns out easily.
• Not to be located near ports to avoid being blown
  out or scraped into (scav manifold)
• There must be adequate nr. Equally spaced holes
  for complete coverage of wall surface.
• Means to distribute.oil grooves to be provided.

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CYL LubricationCloverleafing

• This corrosive wear down is caused due to lower
  alkalinity of cyl oil.
• Alkali gets depleted before full liner wall
  coverage with the oil.
• Corrosive wear takes place between inj. Points
• Causes blow past of comb gases liner failure
• Alkalinity level must be accurate. Too much, or
  too little are both damaging.

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CYL LinerCloverleafing
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CYL Lubsystems/methods.

• Traditional
• i) Timed Lubrication (MAN-BW)
• ii) Accumulator Lubrication (wartsila/sulzer)
• Modern Systems
• i) Alpha Lubrication (AACC)MAN-BW
• ii) Pulse Lubrication (Wartsila)
• SIP swirl Injection Process (CIMAC)
• The traditional systems are mechanical.
• The modern systems are computerized, technically
  advanced give better economy.

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CYL Lubrsystems
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CYL Lubrsystems/methods

• Traditional, timed and accumulator systems inject
  oil through mechanical lubricator units having
  small reciprocating pumps(for each quill),
  through gear/engine drive and ratchet mechanism.
• Purpose of timed lubrication is to deliver oil
  at specific time in relation to piston movement
  during upward stroke.

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CYL Lubrtraditional systems

• Quantity delivered in the timed lubrication
  system factors
• i) (MEP/BHP) ie Load dependant regulation.
• ii) Sulphur content in fuel.
• iii) LCD (Load change dependant) Increased
  lubrication at manoeuvring, engine stop and
  start, works as a kind of conservation and
  priming.

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Cyl LubrAccumulator syst.
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Cyl LubrAccumulator syst..

• The accumulator stores potential energy by
  compressing a spring to exert force against a
  relatively incompressible fluid.  The
  accumulator can use a smaller fluid pump because
  it stores energy in periods of low power demand.
  The energy is available for an instantaneous use
  and released at a rate many times greater than a
  pump alone could supply. If the supply tube is
  kept under sufficient pressure by the counter
  pressure in the non-return valve, the desired
  injection timing is achieved.

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CYL LubrModern systems

• Objectives
• i) To achieve better timing of delivery.
• ii) To deliver optimum quantity at all loads.
• iii) To reduce operating costs.
• Alpha Lubr System (MAN-BW)
• Also called Alpha Adaptive Cyl oil Control
• AACC. The ACC factor is the determining factor in
  the feed rate equation Feed rate  ACC factor 
  sulphur.
• This Algorithms is used to control cyl oil dosage.

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CYL LubrAACC

• An ALGORITHM is programmed in a computer and
  processes a self contained sequence of actions
  that are to be performed.
• Algorithms can perform calculations, data
  processing and reasoning tasks to give end
  results instantaneously.
• The AACC injects a specific vol of oil every
  2/3/4 or 5 revolutions of the engine.
• Controlled by MCU which calculates inj freq on
  basis of rpm by tacho-gen fuel index.

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CYL LubrAACC principle
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CYL LubrAACC principle

• The Computer synchronizes itself with No.1 unit
  of engine when at TDC.
• Injection function controlled by MCU by sending
  on/off signal to solenoid v/v.
• After short duration off signal sent to
  solenoid v/v to shut system pressure open
  return oil.
• Pump stn delivers oil to lubricators at 45bar.
• Power to inject oil comes from 45bar syst pr
  acting on larger piston (moved by solenoid)
• Similar to Common Rail fuel injection in Engines.
  

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CYL LubrAACC principle
LAYOUT DIAGRAM
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CYL Lubr.AACC principle
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CYL Lubr..AACC principle

• Pump stn has 2-Pps one operating while other on
  auto st by duty.
• MCU receives rpm, load index, lubricator piston
  position feedback signals.
• In the event of fault, sends alarm slow down
  action for engine.
• Injection is intermittantevery 2/3/4/ or 5 rev.
• Actual dosage computer determined based on
  gm/bhp/hr

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CYL LubrAACC Lubricator
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CYL Lubr.AACC working

• A single lubricator has 5/6 plungers, driven by a
  single hydraulic piston.
• Hydraulic pr is controlled by the solenoid.
• Piston movement monitored by feedback sensor to
  confirm function and relay signal to
  automatically adjust injection timing.
• Set timing starts oil injection before 1st ring
  passes oil quill and ends just after last ring
  passes the quill.

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CYL LubrAACC oil pr compared
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CYL LubrAACC working

• Piston rings are like scrapers. Above top ring
  oil is burnt out. Below bottom ring is scraped to
  under piston spaces.
• Oil between rings provide the reqd lubrication
• Oil consumption AACC 0.7g/BHP/hr
• Used in Intelligent Engine concept with
  intermittant delivery.
• It has sulphur algorithm inbuilt into system.

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CYL LubrPULSE Lubrication.

• System used by WARTSILA sulzer engines
• Pulse system is similar to the Alpha unit as both
  have electronic computer controlled functions.
  (Has Pulse Jet, Pulse Feed systs)
• In the Pulse system,the dosage pump is the
  central component which delivers a metered
  quantity oil as reqd., and based on principal
  factors of load index and Sulphur content in
  fuel.
• Objective Reduce operational costs.
• It has the CL-4, CL-5, CL-6 variations

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CYL Lubr.Pulse Lubrication
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CYL Lubr.Pulse lubrication
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Cyl lubrPulse lubrication working

• WECS on signal, opens solenoid v/v to pass servo
  oil. This presses C-Piston to inject oil.
• Slanted groove delivers oil sideways.
• After injection, narrow passage in piston allows
  refill of duct storage with metered qty.
• This ensures WECS calculated dosage in duct as
  per sulphur content and load index.
• Servo oil circuit is separate, and a common rail
  arrangement.

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Cyl LubrPulse Lubrication
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CYL LubrPulse lub..working

• WECS-Wartsila Engine Control System is used
• Normally has 8 quills on liner in single row.
• Oil from tank through 40micron filter to Pump
• Quills have storage space for metered qty oil.
• Metered qty can be changed by Central Piston
  positioning in quill. (diagram)
• Crank angle sensors send signal to control unit
• High pr (200bar) servo oil reduced to 50bar
• Reduced oil pr delivered to Dosage pump.

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CYL LubrSIP by CIMAC

• SWIRL INJECTION PRINCIPLE (CIMAC)
• This principle is not based on timing or quantity
  dosing against load index.
• It is based on how effectively the oil is
  distributed to give good circumferential
  distribution and adequate (alkaline) oil film
  with as least quantity, as possible.
• It is made possible to inject a spray of droplets
  tangentially to cyl liner wall. Piston movement
  helps spread vertically. (diag)

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CYL LubrSIP (Swirl Inj Principle)
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CYL Liner Calibration

• Cylinder liners of 2-St engines are gauged at
  6000 to 8000 hrs. (modern engines 18000)
• Inspection carried out immediately after piston
  removal (without cleaning of surfaces/parts)
• Scrutiny of following areas important
• i) Surface cracks on combustion belt.
• ii) Hard rubbing points on surface.
• iii) Ridge formation at top ring terminus.
• iv) Blockage of lube oil quills.

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CYL Liner Calibration

• v) Sharp edges at port walls.
• vi) Cracks on bars at scav/exh ports.
• vii) Accumulation of carbon at scav ports.
• Inferences may be drawn on above observations.
• Liners are gauged with an inside micrometer
  calibrated against a master gauge.
• The temperature of liner need be the same as
  during previous readings.

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CYL Liner.defects to observe
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CYL Liner Calibration

• Micrometer and extension bars kept on liner to
  reach same temperature.
• Readings taken at a nr of vertical points.
• A template is used to ensure same points of
  measurement as previous.
• Readings taken in P-S F-A directions.
• Readings are tabulated to compare previous
  records and check wear down.

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CYL Liner wearcalibration
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Cyl Liner wearTabulation
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CYL Liner wear.

• How wear rate of liner obtained
• Wear rate since last record
• increase in dia since last record x 1000
• running hrs since last record
• Wear rate since new
• total increase in diameter x 1000
• total running hours since new

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CYL Liner wear..graph
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CYL Liner wear

• THANK YOU
• S K Mukherjee
• IMU Kolkata Campus