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Turbo Seminar

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Restriction in Engine Exhaust /Intake Manifold PRV Opens Prematurely (At Too Low a Pressure) ... Manifold Pressure From the throttle plate to the cylinder intake port. – PowerPoint PPT presentation

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Title: Turbo Seminar


1
Boosting Your Knowledge of TURBO-
CHARGING
Randy Knuteson Analytical / Air Safety
2
1905 Patent by Dr. Alfred J. Buchi
3
Historical Perspective
  • 1905 Sulzer Bros. designs first turbo
  • 1910 G.E. begins manufacturing turbos
  • 1915 First turbo diesel engine
  • 1918 Dr. Sanford Moss altitude tests a 350 hp
    turbocharged engine.

4
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5
Historical Perspective
  • 1920 New altitude record in a LePere
  • Bi-Plane 33,113 feet!

6
Historical Perspective
  • 1921 John Macready's flight to 40,800' in an
    open cockpit Lusac 11, Lepere biplane.

7
Turbo-Supercharged B-36
Six 28-Cylinder Engines
Without Turbos 90 Cylinders per Engine!
8
ENGINE HORSEPOWER DEPENDS ON
  • The amount of fuel and air an engine burns.
  • The density of the charge, not the volume.

Soactual power is determined by the MASS of air
consumed.
9
PRINCIPLES OF TURBOCHARGING
Sea-level air density 0.0765 lb. cu. ft.
At 10,000 ft. air density 0.0565 lb. cu. ft.
A Naturally-Aspirated Engine
100 hp _at_ sea-level
73.9 hp _at_ 10,000 ft.
10
WHY TURBOCHARGE?
  • Power diminishes with an increase in altitude.
  • Gain more power and increase engine efficiency
    without enlarging the powerplant.
  • Recapture the heat energy normally wasted out the
    exhaust.

GOAL Convert Exhaust Energy into Manifold
Pressure
11
A TURBOCHARGER IS AN
  • AIRPUMP powered by the unused heat energy
    normally wasted out the exhaust.

12
Routing of exhaust and compressor discharge air
Filteredambient air inlet
Compressor outlet
Spent exhaust gases overboard
Exhaust gas inlet (T.I.T.) from the combustion
process
13
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14
1650 F
As high as 125,000 RPMs!
15
TURBOCHARGING DEFINITIONS
  • Turbocharging
  • BOOSTED HP increase (31-45MAP)
  • Turbo-Normalizing
  • NORMALIZED Maintains sea-level performance
    (29.5 MAP) at altitude.

16
TURBOCHARGING DEFINITIONS
  • Upper Deck Pressure
  • From compressor discharge to the throttle plate.
  • Manifold Pressure
  • From the throttle plate to the cylinder intake
    port.

17
Sludge build-up in the wedge can decrease the
oil pressure feeding into the bearing and shaft
18
TURBO COMPONENTSCENTER HOUSING home of
  • BEARINGS
  • For locating the turbine shaft
  • SEALS (Piston Rings)
  • Prevents high-pressure gases from entering the
    center housing and therefore the crankcase.
  • To keep air and exhaust out of the oil.

19
30-60 PSI
Piston rings keep air and exhaust pressures out
of the center housing
20
TURBO COMPONENTSCOMPRESSOR STAGE (Cold Side)
Discharge Air
Volute shape converts velocity energy into
pressure energy
21
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22
Power increase
Exhaust volume increases
MAP increases
TURBO RUN-AWAY COULD EXCEED MAXIMUM ENGINE
OPERATING LIMITS!
Increased compressor discharge
Turbo begins to spin faster
23
Decrease power
Decreased exhaust flow
MAP decreases
Compressor discharge decreases
Turbo slows down
24
4 BASIC SYSTEM COMPONENTS
  • Turbocharger
  • Controller
  • Wastegate
  • Absolute Pressure Relief Valve (PRV)

25
4 BASIC SYSTEM COMPONENTS
Aneroid Bellows
Upper Deck Pressure
Oil restrictor Valve
Engine Oil from Wastegaate Actuator
Oil Return to Engine
Throttle Controlled Cam
26
4 BASIC COMPONENTS
  • Wastegate (Exhaust Bypass Valve)

Oil Outlet to Controller
Butterfly Valve
Piston
Oil Inlet
Drain Port
27
4 BASIC SYSTEM COMPONENTS
  • Absolute Pressure Relief Valve (PRV)

Spring and Bellows Assy
Valve Face
Escape path for excess Upper Deck Air Pressure
Valve Seat
28
Turbo output pressures must be regulated.
Without a control system, the turbocharged engine
would Be extremely unstable.
29
Why Use an Intercooler?
  • The compressor wheel spins faster at altitude
    producing a hotter charge to the cylinders.
  • Decreasing adiabatic efficiency.

30
TURBOCHARGERS ARE SENSITIVE TO
  • Insufficient lubrication
  • Foreign object damage
  • Extreme temperatures

31
INSUFFICIENT LUBRICATION
  • RESULTS IN
  • Bearing damage that causes an increase in the
    orbital motion of the turbine shaft.
  • Turbine and compressor wheels begin to contact
    their respective housings.

32
CONTAMINATED LUBRICATION RESULTS IN
  • Damage to bearing(s)
  • Collateral damage to turbine and compressor
    housings
  • Full floating bearings require 30 PSI minimum at
    inlet (3 GPM)
  • Engine Oil should be changed every 25-35 hours
    in a turbocharged engine.

33
Lubricating Oil Recommendations
  • Lycoming SI 1014M All turbocharged engines
    must be broken-in and operated with ashless
    dispersant oil only.
  • TCM M87-12 Rev 1 Straight Mineral Oil
    (MIL-L-6082) may be used not to exceed 25 hours
    or 6 months of operation.

34
VERIFY TURBO CONDITION
  • Does the shaft spin freely?

35
VERIFY TURBO CONDITION
  • Wheels should not contact housing.

36
VERIFY TURBO CONDITION
Use a light source to carefully examine the
condition of the leading edges of the Turbine
Wheel blades.
Check inducer blades for damage
37
FOREIGN OBJECT DAMAGE
  • Bolts, valves, and rocks will break pieces from
    the blades or machine them down.
  • Abrasive matter (sand, dirt) will wear away the
    underside of the blades.
  • Soft material (shop rags) will bend the
    compressor blades backwards.

38
Avoiding Turbo Oil Leaks
  • Drain ports must point down. (not more than 35
    degrees from vertical centerline)
  • Drain line should slope entire length (no sink
    traps).
  • Check hoses for internal de-lamination.
  • No sludge at outlet From coking of bearing
    housing.
  • Restriction or faulty check valve(s)

39
TROUBLESHOOTING LOW/FLUCTUATING MAP
  • Restriction in Duct Between Air Cleaner and
    Intake Manifold.
  • Restriction in Engine Exhaust /Intake Manifold
  • PRV Opens Prematurely (At Too Low a Pressure)

40
TROUBLESHOOTING LOW/FLUCTUATING MAP
Leaking Cover Gasket
  • T/C Output Low/Sluggish
  • Engine Oil Pressure Low
  • Controller/Wastgate Dirty or Sticking
  • Controller Cover Gasket Leak

No Split-Lock Washers
41
CONTROLLER MALFUNCTIONS
  • Dirt / Debris in Poppet Valve
  • Worn Poppet Seat Assembly
  • Case / Gasket Leakage

42
Wastegate Malfunctions
  • Sticking / Frozen Butterfly valve

Caused by
Lead and E.G. deposits build-up on pivot bushings
Cure
Mouse Milk
43
Testing the Wastegate Assy.
44
How NOT to Check the Condition of the Pressure
Relief Valve
WARNING Never advance the throttle boosting
manifold pressure beyond red-line to determine if
the absolute pressure relief valve is
functioning. This is an emergency controller.
DONT TEST THE ABSOLUTE PRESSURE RELIEF VALVE ON
THE ENGINE!
45
Overspeed/Overshoot/Overboost
  • Overspeed
  • Operating an engine above its rated speed or RPM.
  • Overshoot
  • Automatic controls cant respond quickly enough
    to the inertia of the turbocharger speed as it
    increases when the throttle is rapidly advanced.

46
Overspeed/Overshoot/Overboost
  • Overshoot
  • Lycoming says

If overshoot does not exceed 2 inches and 3
seconds duration, it may be disregarded.
47
Overspeed/Overshoot/Overboost
  • Overspeed
  • Overshoot
  • Overboost
  • Occurs when the manifold pressure exceeds the
    limits at which the engine was tested and FAA
    certified.

48
OVERBOOST CAUSED BY
  • Rapid throttle movement
  • Exhaust By-Pass Valve fails to open.
  • Sticking Wastegate
  • Air in the oil feed to the controller
  • PRV (pop-off valve) fails to open at
    predetermined crack point.

49
UNACCEPTABLE OVERBOOST
  • TCM SB67-12
  • OVERSHOOT / OVERBOOST
  • 3-6 INCHES Check System, Adjust or Replace
    Malfunctioning Components.

50
UNACCEPTABLE OVERBOOST
  • LYCOMING MSB-369J
  • Not exceeding 5 inches Hg. or 10 seconds
    Normal 50 hour inspection required.

  • Not exceeding 10 inches Hg. Complete engine
    disassembly and inspection.
  • Over 10 inches Hg. Complete engine Overhaul
    and crankshaft replacement.

51
ACCEPTABLE OVERBOOST
  • LYCOMING MSB-369J
  • Momentary - not exceeding 3 inches Hg. for 5
    seconds

Log Book entry required.
  • Maximum manifold pressure reached.
  • Duration of overboost
  • Cylinder head temperature
  • Ambient air temperature
  • Pressure altitude

52
ACCEPTABLE OVERBOOST
  • LYCOMING MSB-369J
  • Visual inspection of compressor and turbine
    wheels
  • Manually check for excessive movement of turbine
    shaft in the journal bearings.

53
CHECKING BEARING CLEARANCES
Radial Bearing Check
0.003-0.007
0.004-0.009
Axial End Play Bearing Check
54
Maintenance of Turbo System
  • Preflight Visual Inspection
  • Check for security of turbo mountings and
    connections.
  • Inspect for evidence of oil leakage, air leakage,
    or exhaust leakage.

55
Maintenance of Turbo System
  • 50 and 100 hour inspections
  • Inspect the hoses and tubing of the air intake
    system.
  • Check for leakage due to cracks, damaged gaskets,
    loose clamps or connections.
  • Restrictions due to kinks, collapsed hoses, or
    dented tubing.
  • Inspect for exhaust leakage.

56
Maintenance of Turbo System
  • 50 and 100 hour inspections
  • Inspect the torque on all V-band clamps

57
Maintenance of Turbo System
  • 50 and 100 hour inspections
  • Check oil feed and return lines.
  • Unusual noises or vibration.
  • Observe the engine exhaust.
  • FOD damage to wheels or evidence of contact with
    housings.

58
Turbo Cool Downs
  • Allow for a two to four minute cool-down period.
  • CHT drop 50 degrees from last power reduction
  • EGTs 500 degree drop from Cruise Temps.

59
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