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 Patm Intake Compression Power (expansion) Exhaust Intake TDC BDC stroke stroke stroke stroke 0 (a)Actual four-stroke spark-ignition engine 2 -TDC Isentropic BDC Isentropic out TDC BDC v 上降充通大学 May9,2019 11 SHANGHAI JIAO TONG UNIVERSITYMay 9, 2019 11 Otto Cycle The ideal cycle for spark ignited engines: 1 2 3 2 3 4 1 4 qout win qin wout TDC BDC