Close the throttle and slide. A badly burned BMW

The poor application of DEM is the reason for the poor combustion of BMW when the throttle is closed. When driving with a small throttle opening (engine speed is lower than1500rpm), release the accelerator pedal to slow down. When the engine speed is lower than 1000 rpm, the mixture becomes extremely rich; As a result, the air-fuel ratio control starts to be reversely adjusted, and the fuel injection amount is reduced. When the engine speed is reduced to normal idle speed, the intake valve is opened for a long time, and more air enters, which leads to too thin mixture in the combustion chamber, and then the engine is turned off, resulting in poor combustion during taxiing.