Overheating protection method for motor of air inlet throttle valve and engine post-processing system

The invention discloses an overheating protection method of a motor of an air inlet throttle valve and an engine post-processing system, and relates to the technical field of engine post-processing. The overheating protection method for the motor of the air inlet throttle valve comprises the following steps that the real-time air inlet temperature of an air inlet channel and the real-time duty ratio of the motor are monitored; the duty ratio limit value, corresponding to the current air inlet temperature, of the motor is obtained; whether the current duty ratio of the motor is larger than or equal to the duty ratio limit value, corresponding to the current air inlet temperature, of the motor or not is judged; and if yes, the duration when the current duty ratio of the motor is larger than or equal to the duty ratio limit value of the motor corresponding to the current air inlet temperature is monitored, and if the duration is larger than first preset time, the maximum duty ratio of the motor is limited. The t