This is the cycle of many automobile engines and other four-stroke SI engines.In a real engine, the beginning of the stroke is affected by the intake valve
 not being fully closed until slightly after BDC.The end of compression is affected by the1.This ideal
 cycle is called an Otto cycle, named after one of the early developers of this type of en
gine.The Otto cycle is the air-standard model of most four-stroke SI engines of the last
 140 years, including many of today's automobile engines.The intake stroke of the Otto cycle starts with the piston at TDC and is a constant
pressure process at an inlet pressure of one atmosphere (process 6-1 in Fig.to 35?C hotter than the surrounding air temperature.