In models with electronic throttle control system
, ECU will analyze the treading depth of throttle in combination with auto conditions when controlling electronic choker, and then calculate appropriate opening width of choker at the current time. When diver speeds up suddenly at the time of start up(tread the pedal to the utmost), ECU will perform analysis according to the current auto speed, opening width of choker and other factors, appropriately restrict the opening width of choker from the perspective of fuel saving and reasonable exhaust emission, and control fuel spray system to restrict maximum spray of fuel injection nozzle at the same time. In this way, driver will feel that automobile begins to start after throttle is treaded for a while, which is the so-called throttle lagging. Therefore, throttle lagging is actually the result of ECU operation through restricting instant output of engine, which can make automobile more environmental-friendly and energy-saving.