Air Intake and Exhaust

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Air IntakeandExhaust
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Air Cleaner System
Filter Media
Dust Cup
Screen
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Air Cleaner Fiber
Dust particle, being denser than air, has too
much velocity to go around fiber, so particle
hits and imbeds on fiber
New fiber
Used fiber
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Centrifugal Type Air Cleaner
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Air Cleaner System
Centrifugal types
Baffle plate
Dust evacuator What makes it discharge particles?
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Air Intake Systems

• Air Cleaner Styles (Kubota / After-market)
• Plastic / Steel / Pre-cleaners
• Single / Dual Element / Minders

Safety element
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• Air Cleaner System

Radial Seal type Air filter element seats on
tapered cone in end of canister.
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• Air Cleaner System

Conventional type
Check for good seating of sealing washer
Check for good seating of air cleaner element
against base of air cleaner housing.
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• Air Cleaner System

Lip type seal, as air intake restriction
increases, lip seal tightens
Square type seal
NOT ALL SEALS ARE GOOD! This type of seal cost
big
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Air Cleaner System
Inspection of element Any problems?
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• Air Cleaner System

Poor air inlet system security, abrasive dust can
enter inlet and engine failure results.
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Air Intake Systems

• Air Cleaner Location / Mounting
• Intake Air Temperature

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Output De-rate (altitude and inlet temp.)
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Air Intake Restriction
Measuring inlet restriction

• Naturally aspirated
• High Idle engine
• speed during test
• Turbocharged
• Full load, max rpm

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10. Exhaust back Pressure

• Check exhaust system has no excessive back
  pressure?
• Performance with muffler removed?

Manometer Location
1mmHg 0.535inAq
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Exhaust Systems

• Calculations / Measurements
• Calculating Back Pressure
• Vibration

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Turbochargers
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What is a Turbocharger?

• Superchargers and turbochargers are devices
  which increase the density of air going into an
  engine
• A supercharger is a constant volume blower that
  is belt driven by the crankshaft
• A turbocharger is a centrifugal compressor that
  is driven by an exhaust gas turbine

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Turbocharger vs. Supercharger

• Both are driven by the
• crankshaft, a
• Supercharger
• by belt, a turbocharger
• by the exhaust stroke
• pushing gas through
• the turbine

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Efficiency

• Turbine is more efficient that belt drive
• Turbocharger can take advantage of exhaust gas
  energy (heat and pulse) that is wasted with a
  supercharger
• Residual/parasitic losses are lower with a
  turbocharger

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Why a Turbocharger?

• Power Density Increased air density (pressure)
  means you can inject more fuel and get more power
  per displacement
• Air Control Increased air supply reduces
  particulates and emissions
• Altitude Correction Derate for altitude is much
  less because turbocharger moves mass not volume

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TurbochargerAltitude De-rate

• Engines move air volume, so they move less air at
  altitude where air is less dense. When air
  temperature increases, density also reduces
• Turbochargers use centrifugal force to move mass,
  so de-rate is much lower.

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Turbocharger Air Flow
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Turbocharger Oil Flow
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Turbocharger Bearings Seals
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Turbocharger Waste-gate

• Limits boost by letting exhaust gas bypass the
  turbine wheel
• Boost pressure pushes on diaphragm and spring and
  pushes open gate valve when boost setting is
  reached

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Why Waste-gate

• A turbocharger turbine housing is like a nozzle,
  a smaller nozzle creates higher velocity, larger
  one allows more flow
• Ideal turbocharger would have small turbine for
  low end response and large turbine for high end
  power
• Simplest solution is to use small turbine with
  waste-gate

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Turbocharger Checks

• Does rotating assembly rotate freely? No metal to
  metal contact with housing. Note that there can
  be considerable amount of radial and axial play
  in new or used turbocharger.
• Does wastegate operate freely and does the
  diaphragm hold air? It is not normally necessary
  to check the calibration unless it has been
  disassembled or damaged.

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Preventive Maintenance

• Run the engine at idle or no load for a period of
  time before shutting down to prevent coking and
  sludging
• Clean air and good oil are essential for long
  turbocharger life

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Waste-gate Calibration

• Install dial indicator on rod and pressure supply
  with gauge on boost line 15psi max
• Read pressure that moves rod 1mm (.039in)
• D1105T 43015 mmHg (8.30.3 psi)
• V1505T 43015 mmHg (8.30.3 psi)
• V2003T 45015 mmHg (8.70.3 psi)
• V3300T 53015 mmHg (10.20.3 psi)
• Note that boost pressure on running engine will
  be lower because exhaust pressure force also
  pushes on poppet

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Troubleshooting

• Black Smoke/Low Power
• Look for dirty air cleaner, blocked ducting to
  turbocharger
• Look for large air leaks in inlet ducting from
  turbocharger
• Check to see if turbocharger rotor rotates
  freely, contact will reduce air flow
• Stuck open wastegate

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Troubleshooting

• Blue Smoke/Oil Consumption
• Look for ring or valve guide problems first.
• Some leakage at idle is normal because seal is
  not positive, restricted air cleaner, high blowby
  can contribute.
• Oil drain blocked
• Wheel contact with housing will destroy the seals
  and cause leakage so look for primary cause of
  damage

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Troubleshooting

• Noise
• Turbochargers make noise, a low pitch one per rev
  noise and a high pitch 6 per rev noise.
• Wheel contact with housing or foreign object
  damage will generate significant noise

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FOD
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NCR
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Turbocharger Damage

• NCR No Cause for Removal
• FOD Foreign Object Damage
• Lubrication Related Problems
• Temperature Extremes
• Materials Workmanship

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Foreign Object Damage

• Hard materials will break off blade tips
• Soft materials such as shop rags or rubber pieces
  will bend back blades
• Abrasives will sandblast and wear away blade
  surfaces

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Lubrication Problems

• Abrasive material
• Foreign material
• Oil diluted with fuel
• Degraded oil
• Coking/Sludging

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Temperature Extremes

• Fuel injection problems or restricted air intake
  can cause temperature problems
• Black Smoke equals High Temperature
• Turbine housing warps or scales

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Repeat Damage

• Three leading causes of turbocharger damage have
  high likelihood of resulting in repeat damage
• Whatever caused original foreign object damage
  may still be in ducting
• Same goes for lubrication and temperature related
  problems

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Turbocharger Replacement

• Use care in reinstalling as dirt can get into oil
  passages. Make sure that gasket sealant does not
  enter the oil passages
• Squirt oil into the oil inlet on the turbocharger
  and spin the rotor to make sure oil gets
  everywhere inside.