SR22T Engine Operations

AIR CAN ESCAPE OPENING VALVE SPRING AND BELLOWS INDUCTION MANIFOLD AIR CAN ESCAPE • An overboost pressure relief valve is incorporated on turbocharged engine models to prevent over pressurization of the induction system • The overboost pressure relieve valve is set to open at roughly 2 to 4 inches of mercury above the rated maximum manifold pressure of the engine • This acts as a “fail safe” device to prevent the engine from reaching an overboost situation Turbo-Supercharger • Turbo uses accelerated exhaust gases to spin a compressor which increases the pressure in the upper deck • Capable of +100,000 RPM • Maximum Normal Turbo Inlet Temperature (TIT) is 1750°F, seen on MFD • Turbo is lubricated via the engine oil system Exhaust Combustion Air Wastegate • The waste-gate is a hydraulically controlled device using engine oil pressure, to close a butterfly valve that will direct exhaust gasses to the turbocharger ENGINE OIL PRESSURE “IN” OIL “OUT” TO SLOPED CONTROLLER Wastegate • The wastegate controls the amount exhaust that is allowed to flow through the turbo • Air will take the path of least resistance • A closed wastegate sends more exhaust through the turbo • An opened wastegate allows Exhaust to bypass the turbo and be dumped overboard • A spring holds the wastegate in the open position. Oil pressure closes the wastegate • There is only 1 wastegate that controls both turbos via a crossover tube Turbo Operation Crossover Tube • The left and right exhaust manifolds are connected via a crossover tube • This architecture equalizes exhaust pressure in the exhaust manifolds and both turbines are driven equally SLOPE CONTROLLER • Moves the wastegate to manage the pressure created by the turbo • Maintains a pressure differential across the throttle valve of about 4“ Hg at partial power settings and limits maximum MAP to 36.5” at full power SLOPE CONTROLLER SLOPE CONTROLLER • On takeoff at full power, slope controller limits MAP to 36.5” • As the aircraft climbs at full power and the ambient pressure decreases, the controller commands the wastegate to close to maintain 36.5” MAP • As power is reduced, the controller commands the wastegate to open to maintain the 4” differential across the throttle plate ADJUSTMENT SCREW OIL INLET PORT DECK PRESSURE SENSING PORT MANIFOLD PRESSURE SENSING PORT ANEROID BELLOWS ASSEMBLY DIAPHRAGM POPPET POPPET SEAT OIL DRAIN PORT ADJUSTMENT SCREW OIL INLET PORT DECK PRESSURE SENSING PORT MANIFOLD PRESSURE SENSING PORT ANEROID BELLOWS ASSEMBLY DIAPHRAGM POPPET POPPET SEAT OIL DRAIN PORT SR22T Power Lever • No connection or linkage to prop governor • Throttle cable “slowed” in cruise power range – Small changes in throttle position result in large changes to manifold pressure due to the slope controller MODIFIED ECS CONTROLLER • SR22T – LARGER HEAT EXCHANGER ON CROSSOVER TUBE, 50°F HIGHER HEAT RISE – USES ELECTRONIC CONTROL TO ACTIVELY MONITOR AND BIAS VALVES IF HOT AIR TEMP EXCEEDS LIMITS – BENEFITS ARE PLENTY OF HEAT ON THE GROUND, AND AT LOW AND HIGH ALTITUDES – PRESSURIZED PREVENTS CO The SR22T incorporates a cable-less Hartzel propeller governor. The governor operates on the same principle as other propeller governors; sensing engine speed, the governor regulates pressurized engine oil in the propeller piston assembly, which controls propeller blade angle. Begins controlling blade angle and engine speed at approximately 1400 RPMs. The engine reaches its maximum speed of 2500 RPMs at power settings as low as 55%. As the power lever is advanced, engine speed will remain at 2500 RPMs, but MAP and Fuel flow will increase as will % Power. With the high speed stop set at 2500 RPMs, additional power input causes the governor to increase propeller blade angle, thus increasing thrust. Prop Governor PUTTING IT TOGETHER So how does this all work? Take-Off • Turbos boost Manifold pressure to ~36.5” • Upper deck pressure regulated to ~36.5” by the slope controller Climb • Outside air pressure will begin to decrease • Manifold pressure would normally start to decrease as well, resulting in a loss of engine power Climb • Slope Controller – The aneroid in the slope controller contracts with loss of manifold pressure Climb • Slope Controller – The poppet closes restricting oil flow, building pressure in engine oil line to the wastegate Climb • The increased pressure in the oil line pushes against the waste gate spring closing the wastegate as needed Climb • As the wastegates close less exhaust air is allowed past the waste gates and more air directed through the turbos • This increase in airflow through the turbos increase the turbo’s RPM Climb • When the turbo’s RPMs increase the compressor will also start to spin faster • An increase in compressor RPMs will result in an increase in the Upper Deck manifold pressure • The upper deck manifold pressure will be regulated to maintain 36.5” up to about 18,000ft (critical altitude) Cruise • Manifold Pressure set to 30.5 or less (power lever) • The Slope Controller maintains upper deck pressure 4” higher (~34.5”) than the intake manifold – Allows for immediate power response • No need to wait for turbos to spool up if additional power is needed Climb to 25,000ft • Wastegates will be fully closed above 19,000ft (Critical Altitude) • All possible exhaust gas is directed through the turbos • As you climb above the critical altitude intake manifold pressure will begin to decrease • Engine should still be able to maintain 31” MAP and 85% power at 25,000 ft Cold Weather Takeoff • Pressure in the oil line to the wastegates may increase more than normal if the engine oil is not properly warmed before takeoff • The wastegate may close prematurely causing higher upperdeck pressures than desired • The pilot should reduce the power lever until MAP is below 37” • The pilot should increase throttle as the oil warms during the climb Cold Weather Departure • If the upperdeck pressure is allowed to reach too high of a level (2” to 4” above max rated) the over-boost valve will open reducing the pressure in the upperdeck LIMITATIONS SR22T Airspeed Limitations Speed KIAS Remarks Vne up to 17,500 MSL 200 (205 G5) Never Exceed Vne at 25,000 MSL 170 (175 G5) Vne is reduced linearly from 17,500 to 25,000 Vno up to 17,500 MSL 177 (176 G5) Maximum Structural Cruising Speed Vno at 25,000 MSL 151 (150 G5) Vno is reduced linearly from 17,500 to 25,000 Note: Vno and Vne can be interpolated for altitudes between 17,500 and 25,000. The PFD airspeed tape will change with altitude to reflect the difference in Vne / Vno System Limitations • Altitude Limits – Maximum Takeoff Altitude…...………………..10,000 MSL – Maximum Operating Altitude...........................25,000 MSL • Flap Limitation – Do not use flaps above………………..............17,500 MSL • Environmental Conditions – Do not operate the aircraft below an outside air temperature of - 40°C • Do not reduce manifold pressure below 15” when above 18,000 ft MSL Critical Altitude • Critical altitude is defined as the altitude at which the wastegate is completely closed and as the aircraft continues to climb, MAP will begin to decrease • Critical altitude ~19,000 ft • Aircraft will still be able to maintain 31” MAP and 85% power at 25,000 ft SR22T NORMAL OPERATIONS Continental Engine Certification • The engine is certified to 14 CFR 33 (Code of Federal Regulations) – Extensive requirements for Detonation – Every approved power setting has a minimum 12% detonation margin • What has CMI proven via testing – Cylinders can survive continuous operation at hot and high power settings – Engine parts remain “within service limits” – The FAA will approve 4X the test period as TBO – It is tested in very abusive conditions 103°F inlet air/240°F oil temp/460°F CHT – High power LOP may not have adequate (12%) Detonation Margin Normal Combustion Detonation • Detonation - Occurs when combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front • If allowed to persist engine damage is likely Detonation • During engine certification, with CHT at 460°F and manifold Air temp > 120°F (obstructions on intercoolers) detonation was observed at 31.5” Manifold Pressure Detonation SR22T Leaning Limitations • Leaning Prohibited if MAP > 30.5” – Detonation Margin • Indicate by Green Arc – Reduced if MAP > 30.7” – Wide if MAP ≤ 30.7” 30.7” Preflight • O2 preflight – O2 quantity, requirements and duration tables – Verify O2 flow to each mask/cannula that will be used • Pulse Oximeter – Check saturation levels on the ground and monitor during flight. – Adjust O2 flow to maintain saturation levels above 90% • Cannulas can not be used above FL180 as per FAR part 23. Masks must be worn above FL180. Plan accordingly. Oxygen Considerations • Do not use cannulas above FL180 • Passengers should be thoroughly briefed on the use of O2 including: – Proper use of masks/cannulas and flow regulators – Recognition and response to hypoxia – Recognition and response to pilot incapacitation • If saturation levels decrease below 90% – Increase to flow of O2 – Increase mask seal around face – Descend to a lower altitude if saturation level can not be maintained above 90% Normal Start (Cold) • Used for first start of the day or when engine (oil temps or CHTs) have cooled to ambient air temperatures Hot Weather Tips • Point the aircraft into the wind to increase airflow / cooling • Open the oil door to allow hot air to escape – Be sure to verify secure/closed before engine start Hot Start SR22T • Used when engine temperature is above ambient air temperature • No priming required for hot starts • Limit starter engagement to 10 seconds – Let cool for 20 seconds Hot Start • Liquid fuel may begin to expand and vaporize in hot weather conditions • Clearing the fuel lines of this vapor will be necessary prior to starting Flooded Start • Used if engine is expected to be flooded or if normal (hot) start was unsuccessful • Weak intermittent firing followed by puffs of black smoke from the exhaust stack indicates over- priming or flooding. Taxi • Leaning during Taxi will help to reduce the likelihood of sparkplug fouling • Lean to the “X” in Mixture or until Maximum RPM rise is achieved Run-Up • Part of the Before Takeoff Checklist – Perform as a flow use checklist to verify • Magneto Check – Max Drop 150 RPMs – Max Differential 75 RPMs • Check Engine Parameters – Verify normal indications Takeoff • Full throttle • Full mixture (for every altitude) • Boost pump on • Monitor MP for overboost – If the MP exceeds 37.0 inches reduce the throttle below 37.0 inches of MP – Due to cooler oil temperatures • Monitor Fuel Flow (Green Arc) – Will increase in proportion to manifold pressure Normal Procedures- Rich of Peak (ROP) Climb • Full Power Climb: Rich of Peak Technique – Power Lever – Full Forward – Mixture – Maintain Fuel Flow w/in Green Arc – CHT – Maintain below 420° F • Airspeed 120-130 Lean of Peak (LOP) Climb • Cruise Climb: Lean of Peak Technique – Power Lever – 30.5” MAP – Mixture – Cyan Target or less • FF Target will bias if CHT > 390 or Manifold air inlet temp increases above 85°F – CHT – Maintain below 420 ° F • Airspeed 120-130 • Lean as required to maintain <420 ° F – If unable use Full Power Climb Lean Misfire • Lean Misfire – Generally observed/characterized by sudden engine roughness • Typically occurs at air: fuel ratios > 18.5 (approximately corresponds to 120°F LOP) Full Power Climb vs. Lean of Peak Climbs Cruise Altitude (MSL) Fuel Savings LOP (Gallons) Range Increase LOP (NM) 2,000 .4 4 4,000 .7 8 6,000 1 13 8,000 1.4 17 10,000 1.8 23 12,000 2.1 27 14,000 2.5 33 16,000 2.9 38 18,000 3.3 44 20,000 3.6 52 22,000 4.2 59 24,000 4.7 67 25,000 5.1 71 Full Power Climb vs. Lean of Peak Climb Consider the following factors when deciding to climb LOP or ROP • Workload associated with LOP climbs – Closely monitor CHT’s – Adjusting mixture/airspeed for cooling • Decrease in climb performance • Significance of fuel savings • Significance of extra range Normal Procedures- Cruise • Cruise- Power settings will be lean of peak – Power Lever – 30.5” MAP or less – Fuel pump- As required • Low boost for at least 30 minutes – Mixture – Cyan target or less • 50 °-75°F lean of peak TIT – CHT’s – Maintain below 420 ° F • IF CHT’s are greater than 420 °F then lean .5 GPH – Should result in a 15 °F reduction in CHT temperature for every .5 GPH • 390° - 400°F CHT’S TYPICAL Boost Pump Operation • Pressure affects the temperature required to vaporize fuel – Lower pressure = lower vaporization temperature • Low boost provides extra pressure to keep fuel from vaporizing at high altitude • High boost may be necessary above FL180 with warm or hot fuel if vapor lock is present • Vapor lock can be recognized in flight by: – Fluctuations in normal fuel flow – Rising EGTs and TIT coupled with falling fuel flow – Rising CHTs Maneuvering • Boost Pump On for any maneuvering – Flight training maneuvers, chandelles, stalls, etc. • Mixture set as required – Normally full rich Descent • Power Lever – As Required • Mixture – Cyan Target or less • CHT – Maintain in green arc (above 240° F) • Avoid Prolonged idle settings • Rapid Descent – Power lever - Smoothly reduce MAP 18 to 20” Before Landing • Mixture (SR20) – Set Full Rich • Ensures for maximum power in case of a go around • Mixture (SR22) – Lean to a setting that will result in placarded fuel flows if throttle is advanced to wide open – Below 4,000ft PA Full Rich • Boost Pump ON Taxi • Leaning during Taxi will help to reduce the likelihood of sparkplug fouling • Lean to the “X” in Mixture or until Maximum RPM rise is achieved REVIEW SR22T Operations True or False? • Leaning the engine will cause the CHT’s to rise when operating lean of peak. Scenario During a lean of peak climb while climbing at 120 KIAS the CHT’s exceed 420° F – What is the appropriate response? – What if that does not work? – What if that does not work? Scenario After setting cruise power at 85% (2500RPM / 30.5” MP and 18.3 GPH) the CHT’s remain at 420° F. – What is the appropriate action? Emergency Procedures Specific to Turbo Operations Scenario • While cruising at 17,000ft you notice a sudden loss of manifold pressure. – What do you do now? Unexpected Loss of Manifold Pressure Four Most Probable Causes 1. Leak in the induction system • Behaves like a normally aspirated airplane 2. Leak in the exhaust system • Possible fire hazard 3. Loss of oil pressure to wastegate actuator • Due to general loss of engine oil 4. Failure of internal component in turbocharger • May be accompanied by loss of oil pressure Unexpected Loss of Manifold Pressure Emergency Procedure: 1. Power- Adjust to minimum required 2. Mixture-Adjust for EGT’s between 1300 ° to 1400 °F 3. Descend to Minimum Safe Altitude from which a landing may be safely accomplished 4. Divert to nearest suitable airfield 5. Radio-121.5 advise ATC 6. Oil Pressure-Monitor 7. Land as soon as possible Questions? Data Review Starter engagement up to 30 seconds observed, Continental and POH limit is 10 seconds with 20 second “cool-down” between tries. Operation near peak EGT: 30.2”MP with 19.3 GPH FF, more normal FF would be around 18 GPH at this MP. This was seen on a couple flights. Excessive time used in transitioning from ROP to LOP, sometimes this exceeds 1 minute. This results in the engine running near peak EGT for longer than necessary. Using the LOP target and more quickly moving the mixture to the LOP target will result in less time at peak EGT. Climbing LOP in the pattern then immediately reducing power