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What are the 4 main components of the induction system?
- Intake
- Filter
- Fuel Air Metering Device
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What are 3 types of carb ice?
- Vaporization ice (throat of carb)
- throttle plate
- Impact Ice (air filter)
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Define absolute altitude?
a/c height above ground
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define pressure altitude?
height that corresponds to given barometric pressure
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define density altitude?
pressure altitude corrected for non-standar temp variations
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What is the basic function of the supercharge?
to increase the weight of the air/fuel charge
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Explain the function and operation of a turbocharger?
small turbine in exhaust system drives centrifugal compressor impeller, creates back pressure on the exhaust
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What are the two types of superchargers? How are these supercharger driven?
- internal- gear driven (supercharger)
- external - driven by an external turbine (turbo)
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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
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When using super chargers/turbos, what is the limiting factor
the internal temp and pressures-causes component failure
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Turbos require oil to stay cool and operate properly, name 3 sources of heat in the turbo?
- friction
- compression
- exhaust
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How is coking oil prevented in the turbo?
oil pump scavenges oil from sump located under turbo, so you don't coke oil
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What is the waste gate valve used for?
- Controls the amount exhaust gas that flows over the turbine wheel
- controls turbine wheel speed
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In a Automatic control system, what is defined as the critical altitude?
The max altitude where the engine can maintain it max MAP
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What is an oil cooler needed ?
The compression of air creates heat
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What two forces are acting on the waste gate ?
- spring pressur closed
- oil pressure open
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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
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What is a APC?
What does it control?
- absolute pressure controller
- controls mainfold pressure
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what is the APC calibrated to>
Where is it located?
- 1" above MAP
- located after the throttle plate, pressure before is upper deck
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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
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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
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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
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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)
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What does the variable absolute pressure controller do?
what does it set the pressure to?
- sense UDP and modulates oil restriction
- 1-1.5"Hg
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What is the Var. absolute pressure controller linked to?
throttle control
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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
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What a 3 components that can be adjusted on the turbo system?
- waste gate actuator
- VAPC
- Ratio Controller
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In the induction system, as air is compressed, what happens to density/
decreases
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What can be added to an turbo indution system to improve the results of compression?
intercooler
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What supercharge design attempts to counter the loss of MAP with altitude gain?
2 stage (altitude engine)
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T/F-Supercharger impellers boost induction system pressure?
False
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Whay is it neccessary for the Ratio Controller to limit turbo out put at altitude?
excess pressure
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If the waste gate valve was siezed in the closed position what would prevent the engine from over boosting?
PRV
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Where is UDP located?
between compressor outlet and throttle valve
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When does the differential pressur controller control the engine?
controls exhaust bypass valve at all throttle settings except full throttle
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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
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