Late 1930s â Hans von Ohain and Frank Whittle separately build pioneering gas turbine engines intended for aircraft propulsion, leading to the pioneering turbojet powered flights in 1939 Germany and 1941 England.
1975 â Catalytic converters are first widely introduced on production automobiles in the US to comply with tightening EPA regulations on auto exhaust.
1980s â electronically controlled ignition improved to reduce pollution.
1980s â electronic fuel injection appears on gasoline automobile engines.