2013-3-6 Introducing Engine Terminology Displacement volume:volume center Top dead center Bore- Stroke Bottom dead center Compression ratio,r:volume at bottom dead center divided by volume at top dead center Introducing Engine Terminology Combustion initiated for every two revolutions of the crankshaft Intake stroke With the intake valve open, piston stroke draws a fresh charge into the cylinder For spark-ignition includes fuel and air. Intake For compression-ignition charge is air 102013-3-6 10 Stroke ►Compression ratio, r: volume at bottom dead center divided by volume at top dead center ► Displacement volume: volume swept by piston when it moves from top dead center to bottom dead center Top dead center Bottom dead center Introducing Engine Terminology Four-stroke cycle Four strokes of the piston for every two revolutions of the crankshaft ►Intake stroke With the intake valve open, piston stroke draws a fresh charge into the cylinder. ► For spark-ignition engines, the charge includes fuel and air. ► For compression-ignition engines, the charge is air alone. Introducing Engine Terminology