Downhill speed control device for heavy-duty vehicle

The utility model discloses a heavy-duty vehicle downhill speed control device which comprises a microcontroller, a vehicle speed relay and an inclination angle sensor, and the microcontroller collects a speed signal of the vehicle speed sensor and an inclination angle signal of the inclination angle sensor and controls the vehicle speed relay and the vehicle speed relay to be in a normally open state. The device is simple in circuit, small in size and convenient to install and connect. As the device is connected with the original line of the vehicle in parallel, the original line of the transport vehicle does not need to be disassembled and changed during line connection; when the vehicle goes downhill, the vehicle speed and the downhill inclination angle exceed the set speed at the sametime, exhaust braking is automatically started, fatigue of a driver can be effectively relieved, and the driving safety of the transport vehicle is improved; due to the fact that the use frequency ofexhaust braking is improve