Debrandstof systeem undertakes fuel filling and transportation. It ensures that the fuel reaches the engine smoothly and is provided for the engine to work. At the same time, it is responsible for collecting oil vapor and filtering it out to the atmosphere. Deabsorption and desorption principle of the evaporation system is that the fuel in the fuel tank produces oil vapor due to changes in ambient temperature. When the vapor pressure is greater than the system set pressure, the two-way valve of the system opens, and the oil vapor enters the canister and is adsorbed by the activated carbon. When the internal pressure of the system is lower than the set pressure, the two-way valve opens, and outside air enters the system through the canister to supplement; when the engine is running, the ECU detects the opening condition of the canister cleaning valve, the canister cleaning valve opens, and the fuel vapor is negative in the intake manifold. It enters the engine to participate in combustion under the action of pressure.