Urea tank and fuel tank assembly

A urea tank and fuel tank assembly, comprising:

• a shell, wherein the shell comprises an upper shell, a middle shell, and a lower shell, the upper shell, the middle shell and the lower shell are welded separately to form a cavity;
• wherein the height of the middle shell accounts for more than ⅓ of the total height of the shell;
• wherein the height ratio of the upper shell to the middle shell to the lower shell is (0.8-1.2):(4-6):(0.8-1.2);
• wherein the upper shell, the middle shell, and the lower shell are separately injection-molded and then welded by hot melting;
• wherein the middle shell is internally connected with a middle grid rib structure, the middle grid rib structure partitions the middle part of the cavity, defined by the middle shell, into several middle grid cavities;
• a first middle grid cavity group comprised in the middle grid cavities contains fuel and a second middle grid cavity group comprised in the middle grid cavities contains urea;
• the middle grid cavities form a matrix structure comprising a plurality of partitions between the first middle grid cavity group and the second middle grid cavity group;
• second middle grid cavities of the second middle grid cavity group are arranged diagonally in the matrix structure;
• the middle grid cavities do not communicate in the horizontal direction at a middle portion, and the bottom end of the first middle grid cavity group is provided with fuel passing ports to communicate with each other to form a fuel cavity;
• and
• a bottom end of the second middle grid cavity group is sealed and side walls of the second middle grid cavity group are provided with urea flow ports to communicate with each other to form a urea cavity.