On-Road Vehicle Driving and Energy Requirements: It’s Impact on Unregulated Exhaust Emissions

Paper #:
  • 2017-01-1013

  • 2017-03-28
The standard emission protocol including driving cycle is performed for the legislative fuel economy and emission testing of the vehicles in a laboratory. The driving cycles are expected to represent actual driving pattern and energy requirements, however, recent studies showed that the gap between real world driving conditions and the standard driving cycle is widening, as the traffic pattern and vehicle population is varying dynamically and the change in the emission procedures is not synchronized with the same pace. More so, as Emission legislations are being harmonized to narrow down the country specific variation of emission regulation and smooth globalization of the automotive business process.. The new regulation for in-service conformity is being considered to reduce the emissions in real world driving. It is important that the new procedure should represent the on-road driving and energy requirements in a better way than the current procedures. This study compares the potential of presently used Modified Indian Driving Cycle (MIDC) and proposed (WLTC) emission test cycle towards assessment of key real world driving parameters like positive kinetic energy, relative positive acceleration and speed acceleration pattern etc. The real world driving trips were performed in urban area in the different traffic conditions of the day. The impact of real world driving trips on the unregulated emissions (Benzene, aldehydes and butadienes etc.) was estimated by International Vehicle Emission models. The Emission results of the currently used driving cycle and the new world harmonized cycle is also compared with the real world estimation to evaluate the potential of both the cycles for the representation of the real world driving and unregulated emissions from gasoline fuelled light duty passenger cars , considering city traffic conditions. International Vehicle Emission Model was used to predict average unregulated emissions. Driving parameters were mathematically calculated and compared with standard test cycles. Real world driving trips were found dispersed in wide acceleration/deceleration range and runs at lower average speed than both the standard cycles. MIDC closely matches with on road driving conditions than WLTC in terms of average speed, standard deviation of speed, average positive acceleration and Root Mean Square (RMS) acceleration, but Positive Kinetic Energy (PKE) and Relative Positive Acceleration (RPA) of road cycle showed more deviation with MIDC than WLTC. The results illustrated that unregulated emissions are better assessed by MIDC than WLTC. This concludes that step towards WLTC falls us back to curb hazardous unregulated emissions.
Also in:
  • SAE International Journal of Engines - V126-3EJ
  • SAE International Journal of Engines - V126-3
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