Abstract

The reduction of pollutant emission from spark ignition engines is desirable in order to reduce the highly impact on the green environment, produced from transport release like trains, trucks, traveler vehicles and others. However, modern vehicles are equipped with catalytic converters. A bi-fuel vehicle that has been retrofitted for both fuel systems: namely, compressed natural gas (CNG) and base fuel gasoline. A locally produced three-way catalytic converter (TWC) fitted on the exhaust system. The objective of this investigation is to evaluate the effectiveness of TWC in reducing vehicle exhaust emissions. In addition, the individual conversion efficiency of the vehicle-out emissions have been calculated and presented. Operations under idle state and on-road emission test procedures were carried out on a newly registered gasoline/CNG bi-fuel vehicle in Egypt market (Hyundai-star) where is assessed against the European standard urban driving cycle (ECE-15). Two different fuel injection systems are used; namely multi-point (MPI) and venture (mixer) closed-loop. The emission results such as CO, CO₂ and THC were measured and compared between the earlier mentioned two fuels. The results show that the arrangement of TWC and operation in idle state is very effective to reduce exhaust emissions than that in transient state. Moreover, the results of this investigation will be used to develop CNG emissions based TWC.

Key words: Vehicle engine emissions, bi-fuel vehicle, idle measurement, on-road measurements, fuel injection systems, air index