دانلود رایگان مقاله نقشه های انتشار و مصرف سوخت موتور از چرخه رانندگی گذرا

Abstract

Air pollution problems persist in many cities throughout the world, despite drastic reductions in regulated emissions of criteria pollutants from vehicles when tested on standardised driving cycles. New vehicle emissions regulations in the European Union and United States require the use of OBD and portable emissions measurement systems (PEMS) to confirm vehicles meet specified limits during on-road operation. The resultant in-use testing will yield a large amount of OBD and PEMS data across a range of vehicles. If used properly, the availability of OBD and PEMS data could enable greater insight into the nature of real-world emissions and allow detailed modelling of vehicle energy use and emissions. This paper presents a methodology to use this data to create engine maps of fuel use and emissions of nitrous oxides (NOx), carbon dioxide (CO2) and carbon monoxide (CO). Effective gear ratios, gearbox shift envelopes, candidate engine maps and a set of vehicle configurations are simulated over driving cycles using the ADVISOR powertrain simulation tool. This method is demonstrated on three vehicles – one truck and two passenger cars – tested on a vehicle dynamometer and one driven with a PEMS. The optimum vehicle configuration and associated maps were able to reproduce the shape and magnitude of observed fuel use and emissions on a per second basis. In general, total simulated fuel use and emissions were within 5% of observed values across the three test cases. The fitness of this method for other purposes was demonstrated by creating cold start maps and isolating the performance of tailpipe emissions reduction technologies. The potential of this work extends beyond the creation of vehicle engine maps to allow investigations into: emissions hot spots; real-world emissions factors; and accurate air quality modelling using simulated per second emissions from vehicles operating in over any driving cycle.

4. Conclusion

Poor urban air quality persists in global cities where large proportions of the population are exposed to harmful levels of pollutants. Regulations to address such emissions, including from road vehicles, are becoming more strict. However, the gap is increasing between predicted (based on the regulatory tests) and real-world fuel use and emissions. One way to increase the accuracy of predictions is by using accurate engine maps simulated over real-world driving cycles. This work presents a method to create engine maps using data gathered from OBD and PEMS while vehicles are operating in the real-world. This work is motivated by the ubiquity of OBD in modern vehicles and the requirement by new vehicle emissions regulations in Europe and the US to employ PEMS as part of in-use conformity tests. The regulatory push to use PEMS implies a large amount of real-world data will become available across a range of vehicles. This work is novel because it uses OBD and PEMS data directly. Conversely, existing methods require steady-state engine maps, obtained from a dynamometer test in most cases, to create a transient counterpart. The method extracts the effective gear ratios from the OBD and uses PEMS output to create a large set of candidate engine maps. A sensitivity sweep of vehicle physical characteristics is used in ADVISOR to find the optimum vehicle configuration based on the smallest sum of Euclidean distances per second between the observed and simulated engine torque-speed pairs per configuration. Similarly, the optimum bins for fuel use and emissions correspond to the smallest sum of absolute deviations per second between observed and simulated data. The resulting maps reproduced accurately the shape and magnitude of fuel use and emissions for the three test vehicles presented such that the difference between simulated and observed cumulative fuel use and emissions was less than 5% in general.