Metodologia para previsão e melhoria da purga do filtro de carvão ativado na fase turboalimentada para emissões evaporativas veiculares

Abstract

Emission limits for vehicles are periodically reduced, and meeting these limits presents a challenge for the automotive industry. In Brazil, there is a transition to Proconve Level 8 (PL8) regulations, which have introduced requirements for Onboard Refueling Vapor Recovery (ORVR), necessitating the use of larger carbon filters. The carbon filter traps hydrocarbon particles while allowing air to pass through. However, over time, the filter becomes saturated, leading to non-compliance with regulatory requirements. To prevent this, it is essential to purge the filter by directing part of the air used for engine combustion through the purge line of the carbon filter. Literature suggests that for effective purging, an air volume three hundred times the volume of the carbon could be a solution. The goal of this work is to develop a simulation methodology to predict and improve carbon canister purge performance during the turbocharged phase. The methodology involves using virtual experimentation tools combined with variations in geometric parameters to evaluate volumetric and mass purge values and comparing these with physical experiments conducted according to PL8 regulations. The study demonstrated that it is possible to predict different purge behaviors based on geometry and identify key points for improving purge performance in the turbocharged phase. A solution was found that improved performance threefold. Thus, the methodology met expectations, but further improvements are needed, such as accounting for pressure losses in the purge line and the carbon filter.