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

Terms

Take-off power =

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:

Fuel metering concepts

fuel characteristics

Aviation gasoline =

NOx =

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 = H2O

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

Carburetion Principles acceleration systems

Acceleration systems

Float Carburetors

Manufacturers

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

Trouble Shooting

common failures

General Notes:

Float Inspections

Main body inspections

Jet and needle valve inspection

Diaphragms, seals, and gaskets

Linkages and cables

Trouble Shooting

Inspection Tips

100 hr insp. float carb.