an idealization of the thermodynamic cycle of the internal combustion engine with air as the working substance: intake of air at atmospheric pressure, then adiabatic compression, then ignition with an increase of pressure and temperature at constant volume, then adiabatic expansion and performance of work, then a drop to atmospheric pressure at constant volume and a rejection of heat to the environment, then the exhaust of air at constant pressure.
an engine cycle used on four-stroke petrol engines (Otto engines) in which, ideally, combustion and rejection of heat both take place at constant volume Compare diesel cycle
- Otto I
noun 1. (“the Great”) a.d. 912–973, king of the Germans 936–973; emperor of the Holy Roman Empire 962–973. /ˈɒtəʊ/ noun 1. called the Great. 912–73 ad, king of Germany (936–73); Holy Roman Emperor (962–73)
- Otto II
noun 1. a.d. 955–983, emperor of the Holy Roman Empire 973–983 (son of Otto I).
- Otto III
noun 1. a.d. 980–1002, king of Germany 983–1002; emperor of the Holy Roman Empire 996–1002 (son of Otto II).
- Otto IV
noun 1. c1175–1218, king of Germany 1208–15; emperor of the Holy Roman Empire 1209–15. noun 1. ?1175–1218. German king and Holy Roman Emperor (1198–1215): invaded S Italy (1210) but was later (1214) defeated by France and deposed