Evaluation of Urban Bi-Fuel Vehicle Exhaust Emission During On-Road Test Facilities

Abstract

Vehicle emissions constitute the main source of atmospheric pollution in modern cities. The increasing number of passenger cars, especially during the last decade, resulted in composite traffic problems with serious consequences on emissions and fuel consumption. However, the present work aims to clear the effect of different operating parameters of the vehicle on their emission characteristics. The on-road emission test procedure was carried out on a newly registered gasoline/CNG bi-fuel vehicle in Egypt market (Hyundai-star) and is now assessed from the European standard driving cycle (ECE-15). The European driving cycle shows the characteristics of vehicles operating conditions for various speeds and acceleration ranges, but does not represent realistic speed-time history of a vehicle in actual traffic. As the driving conditions are different, the assessment results using this driving cycle may not produce realistic amounts of emissions and fuel consumption of the cars under emission tests, which were carried out for urban cycle. Two different fuel injection systems (i.e., multi-point injection (MPI)-sequential and closed-loop venturi-continuous) are used. The vehicle is equipped with infrared gas analyzer and magnetic pickup transducer to measure the concentration of exhaust constituents and engine rotational speed, respectively. The measurements were conducted at different vehicle speed. The results indicate that most of the carbon monoxide (CO), carbon dioxide (CO2), and unburned total hydrocarbons (THC) emission appears at higher load as well as near the idling speed.