01 induction and airflow system

transcript

INDUCTION INDUCTION & &

AIRFLOW AIRFLOW SYSTEMSYSTEM

INDUCTION AND AIRFLOW INDUCTION AND AIRFLOW SYSTEMSYSTEM

PurposePurpose – to provide air in sufficient – to provide air in sufficient quantity to support normal combustionquantity to support normal combustion

Classification :-Classification :-

1) Normally aspirated engine1) Normally aspirated engine

2) Supercharger engine2) Supercharger engine

3) Turbocharger engine 3) Turbocharger engine

NORMALLY ASPIRATED NORMALLY ASPIRATED ENGINE ENGINE

Consist of four major components:Consist of four major components:

1) Air Intake 1) Air Intake

2) Air Filter2) Air Filter

3) Fuel Delivery System 3) Fuel Delivery System

4) Intake Manifold4) Intake Manifold

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINE

1. 1. Air intake Air intake (air scoop)(air scoop)

- - PurposePurpose ~ to direct as much as possible ~ to direct as much as possible ram air pressure into carburetor or other ram air pressure into carburetor or other fuel metering devices.fuel metering devices.

- It is - It is usually foundusually found in the propeller in the propeller slipstream because of the extra velocity slipstream because of the extra velocity the propeller imparts to the airstreams the propeller imparts to the airstreams

- - PressurePressure within air intake is within air intake is higher than higher than any other pointany other point in a normally aspirated in a normally aspirated engine.engine.

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINE1. 1. Air intake Air intake (air scoop)(air scoop)

2. 2. Air FilterAir Filter - - PurposePurpose ~ to prevent any dust, sand, abrasive ~ to prevent any dust, sand, abrasive

materials or other contaminants from entering materials or other contaminants from entering the cylinder.the cylinder.

- Filter - Filter maintenancemaintenance a) Periodic removal, cleaning or replacement of a) Periodic removal, cleaning or replacement of

filter elements is necessary to ensure proper filter elements is necessary to ensure proper engine performance.engine performance.

b) Three type of filters;b) Three type of filters;

(I) (I) Flock Flock (screen wire filled with reusable (screen wire filled with reusable fiber)fiber)

~ clean by washing in safety solvent.~ clean by washing in safety solvent.

~ once cleaned, the filter is soaked in a ~ once cleaned, the filter is soaked in a mixture of engine oil and mixture of engine oil and

preservative oil.preservative oil.

~ once fully saturated, the filter is hung ~ once fully saturated, the filter is hung and allow to dry. and allow to dry.

(II) (II) Paper filterPaper filter

~ similar used in automobile filter.~ similar used in automobile filter.

~ some manufacturer allow to clean it by ~ some manufacturer allow to clean it by blowing the dust in opposite direction to blowing the dust in opposite direction to normal airflow. normal airflow.

~ some filter washed in mild soap and water ~ some filter washed in mild soap and water solution and allowed to dry.solution and allowed to dry.

(III) (III) Polyurethane foam filterPolyurethane foam filter

~ the most effective filter due to the ~ the most effective filter due to the glycol solutionglycol solution which impregnated to the which impregnated to the foam, makes filter sticky.foam, makes filter sticky.

~ the foam element is to be replaced with ~ the foam element is to be replaced with new one, NEVER CLEAN THE FOAM.new one, NEVER CLEAN THE FOAM.

Fuel Delivery SystemFuel Delivery System

- - PurposePurpose ~ to ~ to metermeter the correct the correct amount of amount of fuel/ airfuel/ air mixture enters mixture enters the cylinder the cylinder under all under all operating conditionsoperating conditions. .

- Two types of fuel - Two types of fuel delivery system: delivery system:

(I) carburetor(I) carburetor

(II) fuel injection(II) fuel injection

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINE Intake/induction ManifoldIntake/induction Manifold - - PurposePurpose ~ to direct fuel and air mixture from fuel ~ to direct fuel and air mixture from fuel

delivery system to each cylinders.delivery system to each cylinders.

- - Opposed engineOpposed engine ~ the manifold is bolted to each ~ the manifold is bolted to each cylinder intake port while the other end is attached cylinder intake port while the other end is attached with with short section of synthetic rubber hose and short section of synthetic rubber hose and packing nutpacking nut, to , to provide movementprovide movement between intake between intake pipes and manifold as cylinders expand and contract.pipes and manifold as cylinders expand and contract.

- In some engine, the intake manifold - In some engine, the intake manifold goes through goes through oil sumpoil sump before go to each cylinder, this before go to each cylinder, this promotes promotes better fuel vaporization.better fuel vaporization.

- - Radial engineRadial engine ~ ~ even distributioneven distribution of fuel to of fuel to each cylinder is achieved by each cylinder is achieved by distribution distribution impellerimpeller attached directly behind the attached directly behind the crankshaft. This impeller does not boost the crankshaft. This impeller does not boost the pressure as it operates the same crankshaft pressure as it operates the same crankshaft speed. speed.

- The most - The most important characteristicimportant characteristic of intake of intake manifold, it must manifold, it must maintain gas tight sealmaintain gas tight seal, to , to avoid air leakage and lean mixture. The leakage avoid air leakage and lean mixture. The leakage is noticeable at low RPM. is noticeable at low RPM.

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINEInduction System IcingInduction System Icing

- Icing occurs in induction system will - Icing occurs in induction system will restrict restrict airflow to the engineairflow to the engine, cause engine rough , cause engine rough running, loss power or even quit in flight.running, loss power or even quit in flight.

- the - the conditioncondition induction icing can form when an induction icing can form when an aircraft is flying through cloud, fog, rain, aircraft is flying through cloud, fog, rain, sleet, snow or even in clear air when humidity sleet, snow or even in clear air when humidity is high.is high.

- Classification :-- Classification :-1. 1. fuel evaporation ice/carburetor icefuel evaporation ice/carburetor ice2. 2. throttle icethrottle ice3. 3. impact iceimpact ice

1. Fuel Evaporation Ice/carburetor 1. Fuel Evaporation Ice/carburetor iceice

- caused by :-- caused by :- Decrease of surrounding air temperatureDecrease of surrounding air temperature

due to vaporization of fuel in carburetor.due to vaporization of fuel in carburetor. In the venturi, In the venturi, the higher the air the higher the air

velocity, the lower the temperaturevelocity, the lower the temperature up up to 30°F.to 30°F.

Carburetor ice can occur at ambient air Carburetor ice can occur at ambient air pressure up to 70° when humidity is less pressure up to 70° when humidity is less 50%.50%.

Optimum carburetor ice exists when Optimum carburetor ice exists when outside air temp between 30°F and 40°F, outside air temp between 30°F and 40°F, and relative humidity is above 60%.and relative humidity is above 60%.

- This condition usually - This condition usually occur on carburetoroccur on carburetor type. type.

- - Fuel injection system less prone to Fuel injection system less prone to carburetor icing as fuel is injected at or carburetor icing as fuel is injected at or near intake port of each cylindernear intake port of each cylinder..

2.Throttle Ice2.Throttle Ice caused by ~ caused by ~

a) a) decreased in surrounding air decreased in surrounding air temperaturetemperature at rear side of throttle when at rear side of throttle when it it partially closed.partially closed.

b) b) low pressure arealow pressure area is is createdcreated on the on the downstream side of the throttle valve.downstream side of the throttle valve.

seldom occurs at temperature above 38°F.seldom occurs at temperature above 38°F.

3. Impact Ice3. Impact Ice

- caused by visible moisture - caused by visible moisture striking an striking an aircraft and then freeze.aircraft and then freeze.

- the most prone - the most prone areasareas are are air intake and air intake and air filter.air filter.

- impact icing also may occur at any - impact icing also may occur at any dents and protrusions exist in the dents and protrusions exist in the induction system.induction system.

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINEIce Detection and RemovalIce Detection and Removal

- ice occurrence can be detected through :-- ice occurrence can be detected through :-* * Fix-pitch propellerFix-pitch propeller ~ decrease in engine power is ~ decrease in engine power is indicate by indicate by drop in RPMdrop in RPM and engine roughness. and engine roughness. * * Constant speed propellerConstant speed propeller ~ decrease in engine power ~ decrease in engine power is indicate by is indicate by decrease in manifold pressuredecrease in manifold pressure without without changing in RPM. changing in RPM.

- 3 method of prevention and elimination of carburetor - 3 method of prevention and elimination of carburetor

ice:-ice:- > carburetor heat system> carburetor heat system > spray deicing fluid> spray deicing fluid > alternate air supply> alternate air supply

1.Carburetor heat system1.Carburetor heat system~ consist of ~ consist of heater muffheater muff carburetor heat boxcarburetor heat box~ when carburetor heat is place to “ON”, ~ when carburetor heat is place to “ON”,

unfilteredunfiltered air is drawn from engine cowling air is drawn from engine cowling through through heater muff (heat exchangerheater muff (heat exchanger), this ), this warm air then directs to carburetor air box to warm air then directs to carburetor air box to melt the ice melt the ice

~ ~ fixed-pitch propellerfixed-pitch propeller engine RPM will then engine RPM will then increase.increase.

~ ~ constant speed propellerconstant speed propeller manifold pressure manifold pressure will increase, but engine RPM remain the same.will increase, but engine RPM remain the same.

Heater muffHeater muff

carburetor heat boxcarburetor heat box

~ ~ improper or careless usageimproper or careless usage of carburetor heat of carburetor heat could result; could result;

engine backfireengine backfire loss powerloss power due to decrease in volumetric due to decrease in volumetric

efficiencyefficiency detonationdetonation to high intake air temperature, to high intake air temperature,

especially during take off or high power especially during take off or high power operations operations

~ ~ improper riggingimproper rigging of carburetor heat control of carburetor heat control could also result in failure to develop engine full could also result in failure to develop engine full power.power.

2.Spray deicing fluid2.Spray deicing fluid~ consist of ~ consist of

reservoirreservoir electric pumpelectric pump spray nozzlespray nozzle deicing fluid (alcohol)deicing fluid (alcohol) cockpit controls (deicing)cockpit controls (deicing)

~ when deicing system is in “ON” position the ~ when deicing system is in “ON” position the electrical pump will pump the fluid from electrical pump will pump the fluid from reservoir into upstream of carburetor through reservoir into upstream of carburetor through spray nozzle to melt the ice.spray nozzle to melt the ice.

3. Alternate air supply3. Alternate air supply ~ should impact ice occur, heated air and ~ should impact ice occur, heated air and

deicing fluid are not effective therefore, deicing fluid are not effective therefore, alternate air supply is used. alternate air supply is used.

~ alternate air supply is provided by ~ alternate air supply is provided by carburetor air box from main intake or carburetor air box from main intake or from inside cowlingfrom inside cowling..

~ alternate air door is used in fuel injected ~ alternate air door is used in fuel injected engines, either operated manually from engines, either operated manually from cockpit or automatically.cockpit or automatically.

NORMALLY ASPIRATED ENGINENORMALLY ASPIRATED ENGINETemp. Indicating SystemTemp. Indicating System

- purposepurpose ~ to inform pilot ~ to inform pilot the existence of carburetor the existence of carburetor icing icing

- temperature sensing bulb - temperature sensing bulb is fitted at the carburetor is fitted at the carburetor entrance to sense the entrance to sense the carburetor air temperature carburetor air temperature through Carburetor Air through Carburetor Air Temperature (CAT) Temperature (CAT) calibrated in Centigrade.calibrated in Centigrade.

SUPERCHARGERSUPERCHARGERAA. . Purpose :-Purpose :-

a) to a) to increaseincrease the the Manifold Absolute PressureManifold Absolute Pressure (MAP) above atmospheric pressure 30 in Hg to (MAP) above atmospheric pressure 30 in Hg to provide high power output for takeoffprovide high power output for takeoff

b) to b) to increaseincrease the the weight of fuel/air mixtureweight of fuel/air mixture delivered to engine cylindersdelivered to engine cylinders

c) to c) to increaseincrease the the compression pressurecompression pressure d) to d) to sustainsustain maximum maximum power at high altitudepower at high altitudeBB. Consist of . Consist of similar componentssimilar components to normally to normally

aspirated system with additional of centrifugal aspirated system with additional of centrifugal compressor (supercharger).compressor (supercharger).

CC. . LocationLocation ( fitted between fuel metering device ( fitted between fuel metering device and intake manifold )and intake manifold )

SUPERCHARGERSUPERCHARGER

DD. It is . It is engine drivenengine driven ( by engine ( by engine crankshaft)crankshaft)

EE. . Classified Classified by number of stages : by number of stages : single stagesingle stage two stagetwo stage

multi stagemulti stage

FF. The . The disadvantagesdisadvantages – Supercharger – Supercharger consume large amount of engine power consume large amount of engine power output for the amount of power increase output for the amount of power increase they producethey produce

SUPERCHARGERSUPERCHARGER1. Single Stage, Single Speed Supercharger1. Single Stage, Single Speed Supercharger

~ it is known as ~ it is known as Sea Level SuperchargerSea Level Supercharger or or Ground Ground Boost BlowerBoost Blower

~ it is a ~ it is a single gear driven impellersingle gear driven impeller to increase to increase power produced by engine at all altitudespower produced by engine at all altitudes

~ ~ disadvantages disadvantages of this type is that the engine of this type is that the engine power output still decreases with an increase power output still decreases with an increase in altitudein altitude

~ found on many radial engine~ found on many radial engine

SUPERCHARGERSUPERCHARGER~ intake air passes through carburetor and mixed ~ intake air passes through carburetor and mixed

with metered fuel, then the mixture ducted to with metered fuel, then the mixture ducted to supercharger ( become compressed) and the supercharger ( become compressed) and the mixture direct to cylinder through diffusermixture direct to cylinder through diffuser

~ gear ratio between 6:1 to 12:1~ gear ratio between 6:1 to 12:1

~ the impeller is made of forged ~ the impeller is made of forged high grade high grade aluminum alloyaluminum alloy

~ manifold pressure gauge is fitted after ~ manifold pressure gauge is fitted after supercharger, to supercharger, to determine pressuredetermine pressure of mixture of mixture before entering cylindersbefore entering cylinders

SUPERCHARGERSUPERCHARGER2. Single Stage, Two Speed Supercharger /altitude 2. Single Stage, Two Speed Supercharger /altitude

engineengine

~ it is used on large radial engine~ it is used on large radial engine~ it used single impeller to operate two speed~ it used single impeller to operate two speed

~ low impeller speed is called low blower, gear ratio is 8:1~ low impeller speed is called low blower, gear ratio is 8:1~ high impeller speed is called high blower, gear ratio is ~ high impeller speed is called high blower, gear ratio is

11:111:1

~ the changing of impeller speed is either use lever or ~ the changing of impeller speed is either use lever or switch in cockpitswitch in cockpit

~ ~ during take-offduring take-off, supercharger is in , supercharger is in low blowerlow blower ~ at ~ at high altitudehigh altitude, the supercharger then shift to , the supercharger then shift to high high

blowerblower. The throttle is then set at desired manifold . The throttle is then set at desired manifold pressurepressure

TURBOCHARGER TURBOCHARGER - - PurposePurpose ~ to ~ to maintainmaintain an engine rated sea level an engine rated sea level

horsepower horsepower up to critical altitude. up to critical altitude.- - Critical altitudeCritical altitude is the maximum altitude under standard is the maximum altitude under standard

atmospheric condition that the turbocharger engine atmospheric condition that the turbocharger engine can produce the rated horsepower.can produce the rated horsepower.

- The - The major componentsmajor components are the same as normally are the same as normally aspirated engine with the additional of a turbocharger aspirated engine with the additional of a turbocharger and its associated control.and its associated control.

- The turbocharger is - The turbocharger is locatedlocated between air intake and fuel between air intake and fuel metering device.metering device.

- They compressed the intake air, then send to air metering - They compressed the intake air, then send to air metering section of fuel metering device.section of fuel metering device.

- The compressed air goes through intake manifold into - The compressed air goes through intake manifold into cylinder. cylinder.

- The air and fuel is mixed first in the intake port.- The air and fuel is mixed first in the intake port.

TURBOCHARGERTURBOCHARGER- The turbocharger consist of :- The turbocharger consist of : compressor impeller compressor impeller compressor housingcompressor housing turbine assemblyturbine assembly turbine housingturbine housing bearing housingbearing housing

- Engine oil is pumped through the bearing to cool the Engine oil is pumped through the bearing to cool the turbocharger as it is exposed to hot exhaust gas and compression turbocharger as it is exposed to hot exhaust gas and compression intake air.intake air.

- The rate of oil pumped through the bearing is 5 gal/min and The rate of oil pumped through the bearing is 5 gal/min and flows out back to oil sump through bottom of bearing housing.flows out back to oil sump through bottom of bearing housing.

- Some turbocharger has additional oil scavenge pump.Some turbocharger has additional oil scavenge pump.

- Many turbocharged engine use Many turbocharged engine use Intercooler (heat exchanger)Intercooler (heat exchanger) to to reduce induction air to reduce induction air to prevent detonationprevent detonation..

TURBOCHARGERTURBOCHARGER

Turbocharger Control SystemTurbocharger Control System

- - PurposePurpose ~ to control amount of exhaust gases ~ to control amount of exhaust gases through the turbocharger in order to through the turbocharger in order to prevent prevent excessive manifold pressure excessive manifold pressure (overboosting) (overboosting)

- Amount of exhaust gas passes through - Amount of exhaust gas passes through turbocharger turbine is controlled by turbocharger turbine is controlled by waste gatewaste gate opening or closing.opening or closing.

- Types : - Types : manual control system manual control system

automatic control systemautomatic control system

TURBOCHARGERTURBOCHARGERManual Control SystemManual Control System

- 3 Type : - 3 Type : manual linkagemanual linkage between engine throttle valve between engine throttle valve and waste gate valve (control from throttle/power and waste gate valve (control from throttle/power

lever) lever) push pull controlpush pull control from cockpit with vernier from cockpit with vernier

adjustment adjustment to open the waste (separate control lever to open the waste (separate control lever in cockpit)in cockpit)

adjustable restrictoradjustable restrictor

- For - For take-offtake-off, the waste gate , the waste gate fully or nearly openfully or nearly open

- - As aircraftAs aircraft increases altitude, the engine power decreases, increases altitude, the engine power decreases, pilot will advance the throttle and the waste gate begins to pilot will advance the throttle and the waste gate begins to close.close.

- As waste gate begin to close, manifold pressure increases - As waste gate begin to close, manifold pressure increases proportionally and engine produces its rated horsepower.proportionally and engine produces its rated horsepower.

Manual linkageManual linkage

Push pull controlPush pull control

- When reach - When reach critical altitudecritical altitude, the throttle will be , the throttle will be fully advances and waste gate will be closed.fully advances and waste gate will be closed.

- If using the - If using the Adjustable RestrictorAdjustable Restrictor;; the restrictor is fitted in the exhaust section the restrictor is fitted in the exhaust section

that bypasses turbochargerthat bypasses turbocharger it is fixed and cannot be adjusted from it is fixed and cannot be adjusted from

cockpitcockpit

- Pressure Relief Valve is incorporated to prevent - Pressure Relief Valve is incorporated to prevent overboost. It opens when the manifold pressure overboost. It opens when the manifold pressure rise 1 psi above its rated pressure.rise 1 psi above its rated pressure.

Adjustable RestrictorAdjustable Restrictor

TURBOCHARGERTURBOCHARGERAutomatic Control SystemAutomatic Control System

- This system automatically position waste gate to - This system automatically position waste gate to maintain selected engine power output.maintain selected engine power output.

- It consists of : - It consists of : a) waste gate actuator a) waste gate actuator b) absolute pressure controller (APC)b) absolute pressure controller (APC) c) pressure ratio controller (PRC)c) pressure ratio controller (PRC) d) rate-of-change controller (ROCC)d) rate-of-change controller (ROCC)

a)a) Waste Gate Actuator Waste Gate Actuator- waste gate actuator positions the waste - waste gate actuator positions the waste

gate valve gate valve - waste gate is - waste gate is closed by oil pressureclosed by oil pressure acting acting

on pistonon piston- oil pressure supplied to the actuator from - oil pressure supplied to the actuator from

engine oil system through capillary tube engine oil system through capillary tube restrictor restrictor

- waste gate is - waste gate is open by spring pressureopen by spring pressure

TURBOCHARGERTURBOCHARGERb)b) Absolute Pressure Controller Absolute Pressure Controller- waste gate is controlled by Absolute Pressure Controller - waste gate is controlled by Absolute Pressure Controller - consist of : > bellows- consist of : > bellows

> variable restrictor valve> variable restrictor valve- bellow senses the upper deck pressure- bellow senses the upper deck pressure

- when the - when the upper deck pressureupper deck pressure increases increases ; ; > bellow expands> bellow expands > variable restrictor valve open> variable restrictor valve open > oil flow out from waste gate actuator> oil flow out from waste gate actuator > spring pressure opens the waste gate> spring pressure opens the waste gate

- when the upper - when the upper deck pressure deck pressure decreasesdecreases ;; > bellow contract> bellow contract > variable restrictor valve close> variable restrictor valve close > restrict the oil pressure inside the actuator> restrict the oil pressure inside the actuator > waste gate close> waste gate close

TURBOCHARGERTURBOCHARGER- when engine is - when engine is not runningnot running ; ; > no oil pressure in the actuator> no oil pressure in the actuator > springs held the waste gate open> springs held the waste gate open- - capillary tube restrictorcapillary tube restrictor cause cause oil to flow out of the actuator faster oil to flow out of the actuator faster

than oil flow inthan oil flow in- bellow will expands whenever upper deck - bellow will expands whenever upper deck pressure is 1 inch above pressure is 1 inch above

the desired manifold pressurethe desired manifold pressure- as aircraft climbs :- as aircraft climbs :> air less dense , upper deck pressure drop> air less dense , upper deck pressure drop> bellow contract , restrictor valve close > bellow contract , restrictor valve close > restricts oil flow out of actuator , oil pressure closes the waste > restricts oil flow out of actuator , oil pressure closes the waste

gategate> increase turbocharger speed> increase turbocharger speed> waste gate is fully close at critical altitude> waste gate is fully close at critical altitude> above critical altitude, manifold pressure drop> above critical altitude, manifold pressure drop- variable absolute pressure controller (VAPC) is similar function to - variable absolute pressure controller (VAPC) is similar function to

APC, except the restrictor valve of VAPC is controlled by cam APC, except the restrictor valve of VAPC is controlled by cam actuated by throttle controlactuated by throttle control

TURBOCHARGERTURBOCHARGERc)c) Pressure Ratio Controller Pressure Ratio Controller - purpose :- - purpose :-

~ ~ to monitor both ambient and upper deckto monitor both ambient and upper deck ~ ~ preventprevent turbocharger turbocharger from boostingfrom boosting the upper deck pressure the upper deck pressure

higher than 2.2 times the atmospheric pressurehigher than 2.2 times the atmospheric pressure

- it is fitted parallel to Absolute Pressure Controller (APC)- it is fitted parallel to Absolute Pressure Controller (APC)- consists of : - consists of : ~ ~ bellowsbellows

> one side subjected to upper deck pressure> one side subjected to upper deck pressure > the other side is subjected to atmospheric pressure> the other side is subjected to atmospheric pressure

~ ~ restrictor valverestrictor valve- whenever upper deck pressure is - whenever upper deck pressure is 2.2 times higher2.2 times higher than the than the

atmospheric pressure, the restrictor valve will open, bleeds the atmospheric pressure, the restrictor valve will open, bleeds the oil from the actuator back to engine, then the spring pressure oil from the actuator back to engine, then the spring pressure will open the waste gatewill open the waste gate

- as back up to pressure controller, ‘pressure relief valve’ is fitted to - as back up to pressure controller, ‘pressure relief valve’ is fitted to relief upper deck pressure when it exceeds maximum rated relief upper deck pressure when it exceeds maximum rated pressure by 1 to 1.5 inches pressure by 1 to 1.5 inches

TURBOCHARGERTURBOCHARGERd)d) Rate of Change Controller Rate of Change Controller - - purposepurpose ~ to prevent upper deck pressure from increasing ~ to prevent upper deck pressure from increasing too rapidly during rapid opening of the throttletoo rapidly during rapid opening of the throttle

- fitted parallel to APC & PRC- fitted parallel to APC & PRC

- during normal operation, the ROCC remain seated- during normal operation, the ROCC remain seated

- when the throttle is opened rapidly, the upper deck - when the throttle is opened rapidly, the upper deck pressure will increase immediately, then the ROCC opens pressure will increase immediately, then the ROCC opens and allow oil from actuator to flow back to the engine, and allow oil from actuator to flow back to the engine, spring pressure will open the waste gatespring pressure will open the waste gate

- ROCC is set between 2 and 6.5 in/sec - ROCC is set between 2 and 6.5 in/sec

Sea Level Boosted EngineSea Level Boosted Engine

- engine that uses turbocharger to - engine that uses turbocharger to maintain maintain sea level manifold pressuresea level manifold pressure and and does not boost does not boost manifold pressure.manifold pressure.

- main components : - main components :

a) a) exhaust bypass assemblyexhaust bypass assembly (EBVA) (EBVA)

b) b) density controllerdensity controller

c) c) differential pressure controllerdifferential pressure controller

TURBOCHARGERTURBOCHARGERa)a) Exhaust Bypass AssemblyExhaust Bypass Assembly- purpose ~ to - purpose ~ to direct exhaust gas to drive turbinedirect exhaust gas to drive turbine of of turbocharger OR to bypass the turbochargerturbocharger OR to bypass the turbocharger- consist of : - consist of : ~ piston~ piston~ spring~ spring~ waste gate valve~ waste gate valve~ mechanical linkage~ mechanical linkage- engine oil pressure overcomes spring pressure to close - engine oil pressure overcomes spring pressure to close the waste gatethe waste gate- when oil pressure is released from the exhaust bypass - when oil pressure is released from the exhaust bypass valve assembly, the spring pressure opens the waste gate valve assembly, the spring pressure opens the waste gate valvevalve

TURBOCHARGERTURBOCHARGERb)b) Density Controller Density Controller- purpose ~ to regulate the bleed oil flow from - purpose ~ to regulate the bleed oil flow from exhaust bypass valve assembly exhaust bypass valve assembly during full throttleduring full throttle operationoperation

- consist of: - consist of:

> nitrogen filled bellows> nitrogen filled bellows

> metering valve> metering valve

- bellows is fitted in the upper deck stream and - bellows is fitted in the upper deck stream and sensessenses the the density of upper deck pressuredensity of upper deck pressure

- when density of upper deck pressure is - when density of upper deck pressure is too lowtoo low ; ;> bellow expands> bellow expands> metering valve stops oil flow back to engine> metering valve stops oil flow back to engine> oil pressure in the exhaust bypass valve assembly > oil pressure in the exhaust bypass valve assembly

increase and close the waste gateincrease and close the waste gate

- if upper deck air density is - if upper deck air density is too hightoo high ; ;> bellows contracts> bellows contracts> metering valve open to permit oil flow back to engine> metering valve open to permit oil flow back to engine> oil pressure in the exhaust bypass valve assembly > oil pressure in the exhaust bypass valve assembly

decrease and spring pressure opens the waste gatedecrease and spring pressure opens the waste gate

TURBOCHARGERTURBOCHARGERC)C) Differential Pressure Controller Differential Pressure Controller - purpose ~ to - purpose ~ to monitor the pressure differentialmonitor the pressure differential or drop across throttle or drop across throttle body body during part throttleduring part throttle operation operation

~ ~ reduce the condition of bootstrappingreduce the condition of bootstrapping

- consist of ; - consist of ; > diaphragm – one side expose to upper deck pressure> diaphragm – one side expose to upper deck pressure

- other side expose to manifold pressure - other side expose to manifold pressure > metering valve> metering valve

- typical differential pressure controller is set between 2 to 4 inch - typical differential pressure controller is set between 2 to 4 inch pressure drop across throttle body pressure drop across throttle body

- whenever pressure difference - whenever pressure difference exceeds the preset valueexceeds the preset value;; > the diaphragm moves the metering valve to open > the diaphragm moves the metering valve to open

> oil pressure in exhaust bypass valve assembly is bleed back to > oil pressure in exhaust bypass valve assembly is bleed back to engineengine > spring pressure in EBVA will open the waste gate> spring pressure in EBVA will open the waste gate

> decrease the degree of turbo charging> decrease the degree of turbo charging

Operational ConsiderationsOperational Considerations

- rapid throttle movements will result in:- rapid throttle movements will result in:> overboost the induction system> overboost the induction system> damage the intake manifold > damage the intake manifold > damage the turbocharger> damage the turbocharger> damage the pistons > damage the pistons > damage the cylinders> damage the cylinders> overshoot (not serious as overboost)> overshoot (not serious as overboost)

- avoid rapid throttle movement- avoid rapid throttle movement- operate the throttle gradually- operate the throttle gradually

Additional Turbocharger UsesAdditional Turbocharger Uses

- To regulate the operation of :- To regulate the operation of :

> fuel discharge nozzles> fuel discharge nozzles

> fuel pump > fuel pump

> fuel flow gauges > fuel flow gauges

> cabin pressurization> cabin pressurization

Additional Turbocharger UsesAdditional Turbocharger Uses

TURBOCHARGERTURBOCHARGERTurbocompound/power recovery turbineTurbocompound/power recovery turbine - - purposepurpose ~ to ~ to recover energyrecover energy from velocity of exhaust gases that would from velocity of exhaust gases that would

be lost as the gases routed overboard be lost as the gases routed overboard

- consist of : ~ exhaust collector nozzle- consist of : ~ exhaust collector nozzle ~ turbine wheels~ turbine wheels ~ fluid coupling~ fluid coupling ~ associated gearing~ associated gearing

- - operationoperation : :~ exhaust collector nozzle directs exhaust gases to drive turbine wheels ~ exhaust collector nozzle directs exhaust gases to drive turbine wheels ~ turbine wheels transmits the drive to engine crankshaft through ~ turbine wheels transmits the drive to engine crankshaft through gears and gears and fluid couplingfluid coupling~ fluid coupling is to prevent torsional vibration from being ~ fluid coupling is to prevent torsional vibration from being transmitted to transmitted to crankshaft crankshaft ~ power recovery turbine (PRT) could recover energy up to 390 HP ~ power recovery turbine (PRT) could recover energy up to 390 HP from from exhaust gases.exhaust gases.

Turbocompound/power recovery turbineTurbocompound/power recovery turbine

THE ENDTHE END

01 induction and airflow system

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