Problem Description: at 2:00 p.m. on February 29, 2020, we received the feedback from the commissioning that the urea liquid was fed into the engine, which was verified to be caused by the wrong connection of pipes 6, 8 and 5 in the urea injection pipeline supplied by Hebei Yada. The color code of pipeline 6 and 8 is blue, and the two pipes are connected by tee; the color code of pipeline 5 is green, which is the whole pipe. Single physical pipeline 6, 8 is the whole pipe, and the middle of pipeline 5 is a tee connection. Make urea and cooling pipeline connected.