Along with rapid development of auto industry, auto manufacturers in America, Germany, Japan and other countries successively adopted electronic throttle control system early in 1990s. Electronic throttle control system mainly consists of throttle pedal, pedal displacement sensor, ECU(electronic control unit), data bus wire, servo motor and choker executing mechanism. Electronic throttle is generally adopted in fairly new models. Electronic throttle is named in comparison with fly-by-wire throttle which features direct connection between throttle pedal and choker with thin steel wire. The treading depth of throttle pedal directly corresponds to the opening width of choker. Electronic throttle is free of wire. Treading depth of throttle will be converted into resistance value after a potentiometer(with variable resistance) is mounted in pedal. Electronic system of automobile indirectly determines the depth of pedal through sampling of resistance value. Finally, ECU will activate stepping motor to control the opening width of choker. It can be easily found through principle comparison that drive by wire throttle
features simple system and direct control, with the proportion of the opening width of throttle and choker being 1:1. Characteristics of electronic throttle are as follows: throttle pedal only indicates driver's operating intention, while the final right to control choker belongs to ECU.