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Boosting Your Knowledge of… TURBO- CHARGING. Randy Knuteson – Analytical / Air Safety. Turbo Talk Forum. 1905 – Patent by Dr. Alfred J. Buchi. Historical Perspective:. 1905 – Sulzer Bros. designs first turbo. 1910 – G.E. begins manufacturing turbos 1915 – First turbo diesel engine.
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Boosting Your Knowledge of… TURBO-CHARGING Randy Knuteson – Analytical / Air Safety Turbo Talk Forum
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. Turbo Talk Forum
Historical Perspective: 1920 – New altitude record in a LePere Bi-Plane – 33,113 feet! Turbo Talk Forum
Historical Perspective: 1921 – John Macready's flight to 40,800' in an open cockpit Lusac 11, Lepere biplane. Turbo Talk Forum
Turbo-Supercharged B-36 Six 28-Cylinder Engines Without Turbos – 90 Cylinders per Engine!
ENGINE HORSEPOWER DEPENDS ON… • …The amount of fuel and air an engine burns. • …The density of the charge, not the volume. So…actual power is determined by the MASS of air consumed. Turbo Talk Forum
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 @ sea-level = 73.9 hp @ 10,000 ft. Turbo Talk Forum
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 Turbo Talk Forum
A TURBOCHARGER IS AN… …“AIRPUMP” powered by the unused heat energy normally wasted out the exhaust. Turbo Talk Forum
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 Turbo Talk Forum
1650° F As high as 125,000 RPMs! Turbo Talk Forum
TURBOCHARGING DEFINITIONS • Turbocharging BOOSTED– HP increase (31-45”MAP) • Turbo-Normalizing NORMALIZED – Maintains sea-level performance (29.5” MAP) at altitude. Turbo Talk Forum
Upper Deck Pressure From compressor discharge to the throttle plate. Manifold Pressure From the throttle plate to the cylinder intake port. TURBOCHARGING DEFINITIONS Turbo Talk Forum
Sludge build-up in the “wedge” can decrease the oil pressure feeding into the bearing and shaft
TURBO COMPONENTS:CENTER 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. Turbo Talk Forum
30-60 PSI Piston rings keep air and exhaust pressures out of the center housing
TURBO COMPONENTS:COMPRESSOR STAGE(Cold Side) Discharge Air Volute shape – converts velocity energy into pressure energy Turbo Talk Forum
Power increase MAP increases Exhaust volume increases TURBO “RUN-AWAY” COULD EXCEED MAXIMUM ENGINE OPERATING LIMITS! Increased compressor discharge Turbo begins to spin faster
Decrease power MAP decreases Decreased exhaust flow Compressor discharge decreases Turbo slows down
4 BASIC SYSTEM COMPONENTS • Turbocharger • Controller • Wastegate • Absolute Pressure Relief Valve (PRV) Turbo Talk Forum
4 BASIC SYSTEM COMPONENTS Aneroid Bellows Upper Deck Pressure Oil restrictor Valve Engine Oil from Wastegaate Actuator Oil Return to Engine Throttle Controlled Cam Turbo Talk Forum
4 BASIC COMPONENTS • Wastegate (Exhaust Bypass Valve) Oil Outlet to Controller Butterfly Valve Piston Oil Inlet Drain Port Turbo Talk Forum
4 BASIC SYSTEM COMPONENTS • Absolute Pressure Relief Valve (PRV) Spring and Bellows Assy Valve Face Valve Seat Escape path for excess Upper Deck Air Pressure Turbo Talk Forum
Turbo output pressures must be regulated. Without a control system, the turbocharged engine would Be extremely unstable.
Why Use an Intercooler? • The compressor wheel spins faster at altitude producing a hotter charge to the cylinders. • Decreasing adiabatic efficiency. Turbo Talk Forum
TURBOCHARGERS ARE SENSITIVE TO: • Insufficient lubrication • Foreign object damage • Extreme temperatures Turbo Talk Forum
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. Turbo Talk Forum
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. Turbo Talk Forum
Lubricating Oil Recommendations: • LycomingSI 1014M – “All turbocharged engines must be broken-in and operated with ashlessdispersant 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. Turbo Talk Forum
VERIFY TURBO CONDITION • Does the shaft spin freely? Turbo Talk Forum
VERIFY TURBO CONDITION • Wheels should not contact housing. Turbo Talk Forum
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 Turbo Talk Forum
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. Turbo Talk Forum
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) Turbo Talk Forum
TROUBLESHOOTINGLOW/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) Turbo Talk Forum
TROUBLESHOOTINGLOW/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 Turbo Talk Forum
CONTROLLER MALFUNCTIONS • Dirt / Debris in Poppet Valve • Worn Poppet Seat Assembly • Case / Gasket Leakage Turbo Talk Forum
Wastegate Malfunctions • Sticking / Frozen Butterfly valve Caused by: Lead and E.G. deposits build-up on pivot bushings Cure: “Mouse Milk” Turbo Talk Forum
Testing the Wastegate Assy. Turbo Talk Forum
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. DON’T TEST THE ABSOLUTE PRESSURE RELIEF VALVE ON THE ENGINE! Turbo Talk Forum
Overspeed/Overshoot/Overboost • Overspeed • Operating an engine above it’s rated speed or RPM. Overshoot • Automatic controls can’t respond quickly enough to the inertia of the turbocharger speed as it increases when the throttle is rapidly advanced. Turbo Talk Forum
Overspeed/Overshoot/Overboost Overshoot • Lycoming says: “If overshoot does not exceed 2 inches and 3 seconds duration, it may be disregarded.” Turbo Talk Forum
Overspeed/Overshoot/Overboost • Overspeed • Overshoot Overboost • Occurs when the manifold pressure exceeds the limits at which the engine was tested and FAA certified. Turbo Talk Forum
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. Turbo Talk Forum
“UNACCEPTABLE OVERBOOST” • TCM SB67-12 • “OVERSHOOT” / “OVERBOOST” • 3-6 INCHES – Check System, Adjust or Replace Malfunctioning Components. Turbo Talk Forum
“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. Turbo Talk Forum