The invention discloses a power supply
system of a heavy-duty car SCR
system. The power supply
system comprises a DCU, a
urea pump, a
urea nozzle, a storage battery, a battery main switch and other
electric equipment and further comprises a
relay and a controller controlling the
relay. A
timer is arranged inside the controller. The DCU, the
urea pump and the urea
nozzle are connected in parallel, and then the power supply pin ends of the DCU, the urea pump and the urea
nozzle are connected to a positive
electrode of the storage battery through the
relay. The power supply pin end of the other
electric equipment is connected to the positive
electrode of the storage battery through the battery main switch. The relay and the battery main switch are connected in parallel. The DCU, the urea pump, the urea nozzle and the other
electric equipment are connected in parallel, and then the ground pin ends of the DCU, the urea pump, the urea nozzle and the other electric equipment are jointly connected to a negative
electrode of the storage battery. After the battery main switch is turned off, it can also be ensured that the DCU, the urea pump and the urea nozzle are delayed to be powered on for a certain period of time, and urea
backflow is controlled to be completed. The power supply system is simple in structure, high in reliability and suitable for large-scale application and popularization in the field of heavy-duty cars, circuits of the finished car are changed slightly, and the heavy-duty car can be conveniently refitted and upgraded.