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What are the 4 main components of the induction system?
- Fuel Air Metering Device
What are 3 types of carb ice?
- Vaporization ice (throat of carb)
- throttle plate
- Impact Ice (air filter)
Define absolute altitude?
a/c height above ground
define pressure altitude?
height that corresponds to given barometric pressure
define density altitude?
pressure altitude corrected for non-standar temp variations
What is the basic function of the supercharge?
to increase the weight of the air/fuel charge
Explain the function and operation of a turbocharger?
small turbine in exhaust system drives centrifugal compressor impeller, creates back pressure on the exhaust
What are the two types of superchargers? How are these supercharger driven?
- internal- gear driven (supercharger)
- external - driven by an external turbine (turbo)
A 'altitude engine' with a superchager, is refered to as such for what reason?
- low blower for take off
- high blower for altitude to raise compression ratio in the thin air
When using super chargers/turbos, what is the limiting factor
the internal temp and pressures-causes component failure
Turbos require oil to stay cool and operate properly, name 3 sources of heat in the turbo?
How is coking oil prevented in the turbo?
oil pump scavenges oil from sump located under turbo, so you don't coke oil
What is the waste gate valve used for?
- Controls the amount exhaust gas that flows over the turbine wheel
- controls turbine wheel speed
In a Automatic control system, what is defined as the critical altitude?
The max altitude where the engine can maintain it max MAP
What is an oil cooler needed ?
The compression of air creates heat
What two forces are acting on the waste gate ?
- spring pressur closed
- oil pressure open
What is the function of the capillary restrictor in thw waste gate valve?
at the oil inlet for fast opening of the waste gate valve
What is a APC?
What does it control?
- absolute pressure controller
- controls mainfold pressure
what is the APC calibrated to>
Where is it located?
- 1" above MAP
- located after the throttle plate, pressure before is upper deck
What limits the APC in a altitude engine?
As you climb in altitude, APV valve moves towards close, until you reach the critical altitude at which time, no more exhaust moves across the turbo
What causes the APC valve to open and close?
- Upper deck pressure increases APC valve opens
- Pressure drops, bellows expands moving more exhaust across turbo
What is a Ratio controller?
what does it reference?
When is it used?
- Will not allow UDP to exceed 2.2 times ambient
- ref to UDP and ambient
- Controls at critical altitude and above to allow for high MAP
Define boot strapping?
how can it be overcome?
- Not enough power to the drive turbo
- corrected by a increase in RPM and mixture (changes blade angle)
What does the variable absolute pressure controller do?
what does it set the pressure to?
- sense UDP and modulates oil restriction
What is the Var. absolute pressure controller linked to?
What are 4 of the additional uses of UDP?
- used as a ref for fuel nozzles
- fuel pump
- fuel flow gauge
- can also pressurize the cabin
What a 3 components that can be adjusted on the turbo system?
- waste gate actuator
- Ratio Controller
In the induction system, as air is compressed, what happens to density/
What can be added to an turbo indution system to improve the results of compression?
What supercharge design attempts to counter the loss of MAP with altitude gain?
2 stage (altitude engine)
T/F-Supercharger impellers boost induction system pressure?
Whay is it neccessary for the Ratio Controller to limit turbo out put at altitude?
If the waste gate valve was siezed in the closed position what would prevent the engine from over boosting?
Where is UDP located?
between compressor outlet and throttle valve
When does the differential pressur controller control the engine?
controls exhaust bypass valve at all throttle settings except full throttle
What does the differential pressure controller sense to maintain pressure?
maintains a constant pressure drop across the throttle plate by sensing both UDP and MAP