Fuel Metering & Induction Systems

Question 1

Define stoichiometric mixture.

Answer 1

The fuel-air mixture that, when burned, leaves no uncombined oxygen nor any free carbon. It releases the maximum amount of heat and produces the highest EGT.

Question 2

The stoichiometric air-to-fuel ratio is ________.

Answer 2

15:1

Question 3

The amount of pressure that must be exerted on a liquid to keep it from vaporizing is the ______ _______ _______.

Answer 3

Reid Vapor Pressure.

RVP

Question 4

AV Gas is required to have an RVP (Reid vapor pressure) of _______ psi.

Answer 4

5.5 - 7 psi.

Question 5

If RVP is too high, what happens to the fuel?

Answer 5

Vaporizes too easily.

Question 6

An air-fuel mixture of 12:1 is said to be a _____ _______.

Answer 6

Rich mixture

Question 7

An air-fuel mixture of 17:1 is said to be a _____ _______.

Answer 7

Lean mixture.

Question 8

_______ ______ is added to Avgas to reduce the likelihood of detonations.

Answer 8

Tetraethyl lead.

Question 9

Name the types of carburetors.

Answer 9

1) Float type

2) Pressure type

Question 10

All carburetors use ______________ to meter the correct amount of fuel to the engine.

Answer 10

The volume of air

Question 11

Name the mixture control positions.

Answer 11

1) Full Rich
2) Idle Cutoff
3) Best Power
4) Best Economy

Question 12

Name the metering systems.

Answer 12

1) Main Metering
2) Idling
3) Mixture Control
4) Accelerating System
5) Power Enrichment / Economizer

Question 13

T\F

The main metering system supplies the correct amount of fuel for idle speeds.

Answer 13

False.

All speeds above idle

Question 14

The part that releases atomized fuel into the Venturi of a carburetor:

Answer 14

Main discharge nozzle

Question 15

The atomization of the fuel is made possible by what?

Answer 15

The Air Bleed System

Question 16

The atomization of fuel promotes ______ _________.

Answer 16

Fuel vaporization

Question 17

The ___________ ensures that when the throttle valve is closed, fuel is still supplied to the engine.

Answer 17

Idling system.

Question 18

At ground idle, a rich mixture can do what to the engine?

Answer 18

Provide cooling.

Question 19

The types of mixture control systems are:

Answer 19

1) Variable Orifice
2) Back Suction
3) Automatic Mixture Control

Question 20

The system that regulates the ratio of fuel to air supplied to the engine at speeds above idle:

Answer 20

Mixture Control

Question 21

The type of mixture control system that physically limits the volume of fuel:

Answer 21

Variable Orifice

Question 22

The type of Mixture Control system that limits fuel volume by controlling the pressure difference between the float chamber and Venturi:

Answer 22

Back Suction

Question 23

The automatic mixture control uses a ______ that will actuate the mixture control.

Answer 23

Bellows.

Question 24

At higher altitudes, the bellows will do what?

Answer 24

Expand

Question 25

When the bellows retracts what happens to the fuel-air mixture?

Answer 25

Enriches

Question 26

T/F

Automatic mixture controls are found on float carburetors.

Answer 26

False

Question 27

Automatic mixture controls are found on _______ and _______.

Answer 27

Pressure carburetors

Fuel injection systems

Question 28

Used to momentarily increase fuel to the engine during rapid throttle movements:

Answer 28

Acceleration system

Question 29

The types of acceleration systems:

Answer 29

1) Acceleration Well

2) Acceleration Pump

Question 30

Used during high power to aid in engine cooling:

Answer 30

Power Enrichment System

Question 31

Types of power enrichment systems:

Answer 31

1) Needle Type
2) Air Bleed Type
3) Back Suction Type

Question 32

The disadvantages of carbureted engines:

Answer 32

1) Carburetor Ice
2) Fuel flow interruption during abrupt flight maneuvers.
3) Incomplete Fuel Evaporation

Question 33

The types of carburetor ice:

Answer 33

1) Throttle ice

2) Fuel evaporation ice

Question 34

The band of flammability range is _________.

Answer 34

18:1 to 8:1

Question 35

The two adjustments for setting idling conditions of an engine:

Answer 35

1) The closed position of the throttle. (Affects RPM)

2) The amount of fuel-air mixture discharged. (Idle mixture adjustment)

Question 36

A condition in the rigging of an aircraft engine control in which the stop at the engine is reached before the stop in the cockpit.

Answer 36

Springback

Question 37

Two instruments to observe when performing an idle adjustment:

Answer 37

1) Tachometer (RPM)

2) MAP

Question 38

Primary components of the main metering system:

Answer 38

1) Throttle Valve
2) Venturi
3) Main Discharge Nozzle
4) Main Metering Jet

Question 39

Name the types of variable orifice mixture controls.

Answer 39

1) Needle valve

2) Step-cut rotary valve