Control method for speed limit of AMT (Automatic Mechanical Transmission) type vehicle

The invention discloses a control method for speed limit of an AMT (Automatic Mechanical Transmission) type vehicle. The control method comprises the following steps that: a. an automatic TCU (Transmission Control Unit) receives a current gear signal, an engine revolution speed signal and a clutch slip ratio signal detected by a sensor, and transmits the signals and a determined driving chain combination state signal to a VCU (Vehicle Control Unit); b. the VCU calculates a maximum gear allowed to be switched and a maximum limit value of the engine revolution speed, real time transmits a command signal to an ECU (Electronic Control Unit) and detects whether the current gear is higher than the allowed maximum gear; c. the VCU transmits a gear-switching request command and reduces the current gear to be the allowed maximum gear; d. the ECU regulating a rail pressure and a fuel injection quantity according to the maximum limit value of the engine revolution speed so as to regulating the engine revolution speed to be lower than the maximum limit value; and e. a vehicle regularly runs. The invention has the beneficial effects of largely reducing the labor strength when effectively improving the safety of a driver.