Vehicle emissions and driving cycles: comparison of the Athens driving cycle (ADC) with ECE-15 and European driving cycle (EDC)

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. This project was carried out in the Laboratory of Fuel Technology and Lubricants at NTUA in order to examine the effects of the driving patterns on fuel consumption and exhaust emissions from cars in the Athens basin. The typical driving profile consists of a complicated series of accelerations, decelerations and frequent stops and it is simulated by driving cycles on a laboratory chassis dynamometer. The New European Driving Cycle (NEDC) is applied in laboratory test approvals in the EU and is based on traffic data from European capitals (Paris and Rome). Traffic data from Athens was not included in the development of NEDC. The FTP 75 driving cycle and the Japan 10-15 modal cycle are currently used in the United States and Japan respectively. The different than other European cities and rapidly changing traffic conditions in Athens as well as the expanding transportation network and the atmospheric pollution problems impose the need to develop the Athens Driving Cycle (ADC). In this paper, onboard electronic equipment (GPS, OBD II reader, accelerometer, etc) was used and “real world” traffic data was collected, covering almost all the Athens road network for a two year period. Dedicated software was developed for the statistical analysis of the recorded parameters and therefore the first ADC was modeled with the following characteristics: ADC duration is 1160 seconds, the overall distance is 6512 meters, the mean velocity is 20.21 km h-1 and the maximum velocity is 70.86 km h-1. For comparison purposes, three passenger cars of different classification (Citroen Xsara 1.6L, a Mitsubishi Space Runner 2.0L Turbo and a Chrysler PT Cruiser 2.4L Turbo) were tested on a laboratory chassis dynamometer, applying three distinctive Driving Cycles: the Urban Driving Cycle (ECE-15), the New European Driving Cycle (NEDC) and the newly designed Athens Driving Cycle (ADC). Results show that NOX emissions are higher in ADC than ECE and EDC, up to 2.5 times. Higher CO emissions are recorded during ADC for 1.6L and 2.0L cars while ECE-15 gave the higher CO emissions for the 2.4L vehicle. Overall HC emissions do not show any significant variation. Fuel consumption is higher for ADC mode in all cases.