Otto Cycle The ideal cycle for spark ignited engines: End of combustion Exhaust Air-fuel gases mixture Expansion Ignition Exhaust valve Intake Compression opens Air-fuel valye opens Exhaust mixture P Intake Compression Power (expansion) Exhaust Intake TDC BDC v stroke stroke stroke stroke (a)Actual four-stroke spark-ignition engine TDC Isentropic BDC Isentropic out TDC BDC v 上游充通大率 May15,2018 11 SHANGHA BAO TONG LINIERSITYMay 15, 2018 11 Otto Cycle The ideal cycle for spark ignited engines: 1 2 3 2 3 4 1 4 qout win qin wout TDC BDC