Determination of CO and HC emissions for gasoline and LPG-fueled highway motor vehicles

Abstract

Carbon monoxide (CO), unburned hydrocarbons (HCs), and oxides of nitrogen (NOx) are the major pollutants of motor vehicle emissions. The main fuel used in vehicular transportation is gasoline; the use of liquefied petroleum gas (LPG) is an alternative fuel, which can reduce the environmental impact on the transportation sector. Today, about 700.000 light-duty vehicles circulate in Istanbul and most of them are using aftermarket conversion systems. In this study we have surveyed 41 vehicles of that fleet. Twenty-six vehicles with carburettor systems were chosen, 11 were equipped with fuel injection and the remaining four vehicles with the newest technology avail-able for air pollution control. From the study, it can be concluded that due to poor maintenance, many of the in-use vehicles exceed the environmental regulation standards required for certification. After the tuning up of 41 vehicles, the emission values were reduced below the environmental regulation values. In addition, it was found that CO emission of LPG was 44% less than that of gasoline fuel.