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Aero Engines. 9.01 Four Stroke Cycle and Engine Types References: FTGU pages 51-53. 9.01 Four Stroke Cycle and Engine Types. MTPs: Parts of the Cylinder 4 Stroke Cycle Types of Combustion Engines. Parts of the Cylinder. Piston : moves up and down Bore : hole for piston
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Aero Engines 9.01 Four Stroke Cycle and Engine Types References: FTGU pages 51-53
9.01 Four Stroke Cycle and Engine Types MTPs: • Parts of the Cylinder • 4 Stroke Cycle • Types of Combustion Engines
Parts of the Cylinder • Piston: moves up and down • Bore: hole for piston • Spark Plug(s): ignites fuel • Valves: intake and exhaust • Piston Rod: moves crankshaft • Crank Shaft: rotates prop • Sump: contains oil at bottom • Cam: opens / closes valves
Induction (Suck) • Cam pushes down Intake Valve • Piston forced down by moving Crankshaft • Down-moving piston sucks air/fuel mixture through intake valve Cam Cam
Compression (Squeeze) • Both valves closed • Piston forced upwards by moving crankshaft • Up-moving piston compresses air/fuel mixture
Power (Bang) • Both valves closed • Spark plug ignites fuel air mixture • Piston forced down by expanding gasses • Down-moving piston pushes connecting rod which rotates crankshaft
Exhaust (Blow) • Cam pushes exhaust valve open • Piston forced upwards by moving crankshaft • Up-moving piston pushes exhaust gasses out
Confirmation Match the parts of a reciprocating engine by matching their names with the letter. Cylinder ____ Crankshaft ____ Intake valve ____ Piston ____ Sparkplug ____ Connecting rod ____ Exhaust valve ____
Confirmation Match the actions of a four-stroke cycle by matching the action with the engine diagram. Compression ____ Exhaust ____ Intake ____ Power ____
Horizontally Opposed • Two banks of cylinders on opposite sides of a centrally located crankcase. • Flat design fits inside aircraft nose well. • Common in Cessna aircraft
Radial • Odd number of cylinders (5, 7, 9…) surrounding a centrally located crankshaft. • Single or multiple banks of engines may be used (stacked behind one another). • Cylinders fire opposite each other to reduce vibrations. • Poor shape increases parasite drag and reduces forward visibility.
Inline • Cylinders lined up behind each other, typically underneath crankshaft (aka inverted inline). • Advantage: small frontal cross section (streamlined aircraft nose) • Disadvantage: poor air cooling and long, heavy crankshaft.
Confirmation Match the engines with the correct engine type: • A – Horizontally opposed engine • B – Radial engine • C – In line engine