This paper reports on the preparation of hydrocarbon (HC) trap, which can exhibit the capability to effectively reduce evaporative emission from automotive vehicles. The preparation of HC-trap was accomplished by a dipping method which involved the immersion of a nonwoven material in an aqueous solution containing powdered activated carbon. Four kinds of activated carbon are used for HC-trap preparation. HC-traps were then characterized by scanning electron microscopy (SEM), porosimeter (measurement of pore size ) and tensometer (mechanical properties). We conducted butane working capacity (BWC) and vehicle evaporative emission test to check adsorption performance of evaporative emission. Given the high mesopore volume, the HC-traps exhibited high BWC and low vehicle evaporative emissions. It was also revealed that relatively smaller pore size (5~11 nm) of mesopore could be easily saturated by evaporative emissions with HEEL stabilization. Finally, prepared HC-trap showed excellent performance of vehicle evaporative emission test and high reduction of evaporative emissions which showed 18.4 mg of reduction of total vehicle emissions.

본 논문에서는 자동차의 증발 가스를 효과적으로 감소시킬 수 있는 탄화수소(HC)-트랩을 제조하였다. HC-트랩은 분말화된 네 종류의 활성탄을 함유하는 각각의 수용액에 부직포를 침지시키는 방법으로 제조하였다. 제조된 HC-트랩은 주사 전자 현미경(SEM), porosimeter(기공크기 측정) 및 tensometor(기계적 특성)로 특성을 조사하였다. 또한 증발가스의 흡착성능을 측정하기 위하여 butane working capacity(BWC) 및 차량 증발 배출 시험을 실시하였다. 중간 공극이 높은 경우의 HC-트랩은 높은 BWC 및 낮은 차량 증발 배출량을 보여주었다. 또한 HEEL 안정화 실험에서 상대적으로 크기(5~11 nm)가 작은 중간공극들은 증발가스에 의해 쉽게 포화될 수 있음을 알 수 있었다. 결론적으로 제조된 HC-트랩은 차량 증발가스의 우수한 배출성능과 증발 배출량의 높은 감소를 보여 주었으며, 차량 전체 배출가스 중 18.4 mg의 감소를 나타냈다.

Keywords: hydrocarbon-trap, evaporative emission, automotive

Environmental pollution has become a critical problem in recent years. Air is essential for the survival of organisms. Atmospheric contamination can be lethal to organisms.¹ Atmospheric contamination stems from the combustion process, organic solvent and whole industries but the emission from mobile sources has around 24% of the whole of the emissions.² Global vehicle sales are growing continuously at approximately 5% every year.³ The emerging market is pulling sales volume increase. But the China market which is the biggest market among emerging markets showing the decreased rate of sales increases, and global vehicle sales have been recently shown to increase by just 1.9%.⁴
In particular, automotive vehicles are one of the well-known pollution sources. As such, many countries have constituted and imposed new laws and regulations to minimize environmental pollution. Automotive vehicles generate various gaseous emissions containing hydrocarbons. The major composition of hydrocarbons are butane (C4) ~ dodecane (C12) which are hazardous to human health.⁵ So, highly restricted regulations are proposed every day to reduce evaporative emission. ⁵ Low emission vehicles III (LEV 3) is the most restricted regulation for evaporative emission reduction.^6,7 Maximum evaporative emission of LEV 3 is 0.3 g/test. The evaporative emission is often produced from fuel systems and some technology including Canister is applied to reduce hydrocarbonbased gases in fuel tanks.^8,9 However, reduce of evaporative emission with current technology is not enough to meet everintensifying regulation.¹⁰
In this study, a HC-trap system is newly introduced to reduce the evaporative emission coming out through the air intake system of vehicles. A new concept of HC-trap can reduce evaporative emission effectively because air intake system does not have any technology to reduce evaporative emission. Four kinds of activated carbon were selected, and their effects on the performances of new HC-trap based on their mechanical properties and pore properties were investigated. Tests were performed on the butane working capacity (BWC) to check its performance and then vehicle evaporative emission test.