Numerical simulation of internal flow and adsorption process in an activated carbon canister for ORVR system

In the vehicle fuel evaporation control system, the activated carbon canister is the core component and plays a vital role in the performance of the entire system. In this paper, a numerical simulation of the internal flow and adsorption process of an activated carbon canister used in an ORVR system was conducted to analyze the influence of the structure of the canister on the flow distribution and adsorption process. The research results showed that in the adsorption process, the flow through the activated carbon layer belonged to laminar flow, which was conducive to the full absorption of butane by activated carbon. In the desorption process, the flow velocity reached 0.05-0.09m/s. The higher flow velocity was beneficial to the desorption of the activated carbon. In the initial adsorption stage, due to the high flow velocity through the inlet, the butane concentration distribution was non-uniform, and the activated carbon under the inlet saturated faster than other positions. The activated carbon released heat during the adsorption process. The temperature at each monitor point showed a trend of fast increasing first and then slowly decreasing. The adsorption capacity of each monitor point increased significantly in the early stage of the adsorption process, while in the later stage tended to be stable. The adsorption capacity of butane was directly affected by the temperature of the activated carbon layer. The higher temperature was not conducive to the adsorption process.