Several emission performance tests like Butane Working Capacity (BWC), Cycle Life, and ORVR load tests are required for the certification of a vehicle; these tests are both expensive and time consuming. This paper presents a test process based upon analytical simulation of BWC of an automotive carbon canister in order to greatly reduce the cost incurred in physical tests.The computational model for the fixed-bed system of a carbon canister is based upon non-equilibrium, non-Isothermal, and non-adiabatic algorithm to simulate the real life loading/purging of hydrocarbon vapors from this device. For simulation, the activated carbon bed is discrete and the behavior of carbon in each cell can be described through dependent variables of this methodology (including species concentration, temperature, and pressure) at each time step of the Computational Fluid Dynamic (CFD) analysis; the Dubinin-Astakhov Equation and Lagrange Interpolating Polynomial methods are used to describe the mass transfer and the thermodynamics. The integrated behavior is computed at specified interval to assess the overall performance.The simulation of emission performance is based upon two concepts. The first concept is the Numerical Load / Purge Control System to create a systematic scheme to allow a CFD tool for performing fuel vapor related tests analytically. The second concept is the Carbon Canister Performance Simulation scheme to provide a user subroutine to describe the chemical behavior related to adsorption and desorption of hydrocarbons in the activated carbon bed.