Induction, Cooling, & Exhaust Aviation Maintenance Technology INDUCTION Induction = There are two basic types 1. 2. Non-supercharged components 1. 2. 3. 4. 5. 6. 7. 8. Air Scoop
Air filters. Ducting Hot air valve, muff and ducting Alternate air =
Fuel metering devices 1. 2. 3. 4. Sensors Latent heat of vaporization Laws of evaporation. 1. 2. 3. 4. 5. 6. 7.
Deicing systems Three types of ice. 1. 2. 3. Vaporization ice Throttle ice Impact ice CAT =
Intake system ducting 1. 2. 3. 4. 5. 6. Polished intake Porting and blue printing
MAP Manifold Absolute Pressure Any engine is primarily an air pump. The air throttle valve
The maximum BMEP Common problems, failures and diagnostic techniques Leaks - small
Leaks - large High power flat - Restricted exhaust Restricted fuel flow - Supercharging
Critical altitude = General gas law = high cyl pressure. 1. 2. 3. 4. 5.
Detonation = Pre-ignition = Air Density Factors effecting density Avogadro s law Density altitude = Supercharger Supercharging
Turbo supercharging Stages and speeds. Stages: Speeds:
Advantages 1. 2. 3. 4. 5. Disadvantages, 1. 2. 3. 4. 5. 6.
Distribution impeller = Conversions Supercharger and *Turbosupercharger components. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Compressor housing Compressor impeller Turbine housing
Drive shaft Transmissions Diffusers are two main types: 1. 2. Bearing housing,
Lubrication plumbing The impeller shaft Air ducting Exhaust ducting DO NOT Control systems
Wastegate Throttle valve There are numerous configurations. Density regulator Pressure regulator Simple system
One Lycoming system has four main components 1. 2. 3. 4. Turbo supercharger Density controller Differential controller Variable-pressure controller
Continential 1. 2. 3. Pressure ratio controller
Variable absolute pressure controller Adjustment criteria Bootstrapping
Intercoolers Over boost Turbo compounding
Turbo supercharger problems 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Differential controller malfunctions. 1. 2. 3. 4. Density controller malfunctions. 1. 2.
Aircraft Fuel Metering Purpose of metering Terms Take-off power = Terms Rated Power = Absolute altitude = Friction horsepower = Mechanical efficiency = Brake horse power = Indicated horse power = P = L = A =
N = K = MEP = Otto cycle = 1 2 3 4 5 Density altitude = Carburetor = Metering = Fuel injection = Octane rating Air metering force Fuel metering force Fuel distribution forces
Full rich: Rich best power: Lean best power: Best economy: Best power: Aviation gasoline = Fuel metering concepts fuel characteristics NO x = CO = Volatile =
RON = MON = (RON+MON)/2 = Anti-detonation compound Scouring additives Color Octane BTU s lead ml/gl
BTU = = Natural gas Gasoline's Diesels Jet fuels Spark plug arc Best arc temp The primary purpose of a fuel distribution Turbulence generators 1 2 3 4 5
6 Typical method to repair vapor lock 1 2 3 4 5 6 7 8 9 10 11 Automotive fuels Methyl tertiary butyl ether
Methyl Alcohol Air Nitrogen = N Oxygen = O Water vapor = H 2 O
Avogadro s law Stochiometric ratio Common ranges for aviation engines are:
Fuel metering concepts engine operational needs Some different operating modes are: Starting operations:
Transitional operations: Cruise operations: High power settings: Shut down operations: Altitude - pressure compensation:
Fuel metering concepts basic system outline Fuel storage Systems must have
Pump systems Tubing, hoses, fire sleeve, and filtration as per FAR 23, 33, and 34. Air metering system Fuel metering system Fuel distribution system Air / air-fuel compressor system. Combustion chamber intake valve
Carburetion Principles Air Metering True rotary engine. Air metering
Carburetion Principles Fuel Metering Bernoulli s Principle Venturi effect. Fuel staging Fuel metering Fuel Discharge
Fuel enrichment/derichment Two methods for altering venturi pressures. 1. choke = 2. Alter fuel staging area enrichment / derichment may be used for:
Carburetion Principles Automatic Mixture Controls Acceleration systems Carburetion Principles acceleration systems
Manufacturers Float Carburetors Model identification systems Marvel/Schebler Stromberg-Bendix 5 to 6 groups First Group: Second Group: Fourth Group: Fifth Group:
Sixth Group: Bing Float carburetors Floats Fuel metering force
Idle circuits Float lever Acceleration systems, Fuel enrichment circuits Stromberg
Pressure Carburetors The primary differences between float and pressure carburetors are: Air metering force is created with a pressure differential:
Fuel is regulated
Auxiliary components can include: Accelerator Pump Enrichment / idle control Mixture control circuits
Fuel Injection Manufacturers Bendix Has four main sections Uses the same A, B, C, D, pressures Air metering and regulation Fuel regulation
Fuel metering section includes: Fuel distribution Mixture control Contenintal Continuous Flow Fuel Injection
System operation Anti-Detonation Injection
The system can contain: Three common regulators are: Trouble Shooting basic strategy 1. Verify the complaint.
2. Research - looking for: 3. Perform any indicated tests or repairs from step 2. 4. Analyze the results of step 3. 5. Reverify full system operation for complete repair, and or previously hidden problems. 6. Perform appropriate paperwork entries.
Trouble Shooting general overhaul techniques
General Notes: Trouble Shooting common failures Float Inspections Main body inspections Jet and needle valve inspection
Diaphragms, seals, and gaskets Linkages and cables 100 hr insp. float carb. Trouble Shooting Inspection Tips