On-Road Vehicle Driving and Energy Requirements and Impact on Unregulated Exhaust Emissions under Urban Driving Conditions 2017-01-1013

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 the process of harmonization of emission legislations is in progress to narrow down the country specific variation of emission regulation, as this will help in the 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 the 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 are 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 urban traffic conditions. 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. The WLTC shows around 50% less deviation of relative positive acceleration (RPA) with real world driving as compared to MIDC. However, the average speed of MIDC was observed about 8% closer to real world driving average speed in comparison to WLTC. The butadienes emission were observed around 60~80% higher in real world driving condition as compared to MIDC and WLTC cycles.