Impact of driving dynamics in RDE test on NO_x emissions dispersion

Abstract

EU6D emission regulation intends to bridge the gap between laboratory tests and the real driving conditions by introducing real drive emission testing. It requires the measurement of real drive emission to be an additional type approval test in order to take into account the influence of road profile, ambient conditions and traffic situations. An important amendment has been included in Commission regulation (European Union) 2016/646, limiting the driving dynamics and hence avoiding the biased testing of the vehicle. In this work, a drive cycle generator has been developed to synthesise cycles meeting all the regulatory requirements of the real drive emission testing. The generator is based on the transition probability matrix obtained from each phase of the World harmonised Light vehicle Test Procedure cycle. Driving dynamics have been varied based on real drive emission regulations, and several trips have been generated with dynamics ranging from soft to aggressive. A direct injection compression ignition 1.5 L engine with a state-of-the-art aftertreatment system has been utilised to run the generated synthetic cycles. The analysis of the results obtained in the tests (all of them complying with real drive emission restrictions in terms of driving dynamics) points out a noticeable 60% relative dispersion in the NO x emissions downstream of the catalyst. The contribution of the proposed method lies not only in the fact that it synthesises driving cycles as stochastic process and is capable of tuning the driving dynamics based on real drive emission regulations, but it also presents the range of dispersion possible in NO x emissions solely due to the driving dynamics. The methodology followed in the present work could be an essential step in future engine developments, where testing engine prototypes on the entire range of driving dynamics in the engine test bench facility could provide interesting insights about the expected NO x emissions in real drive emission testing.

Adaptive calibration of Diesel engine injection for minimising fuel consumption with constrained NOx emissions in actual driving missions

“…The study demonstrates a real-time capable application of the Markov-based cycle prediction tool also shown by Luja´n et al 23 The proposed method takes the advantage of available information about the velocity profile on a given route.…”

“…The corresponding Cumulative Probability Function is used to randomly generate velocity for the next time step. The detailed description of the synthesis process is presented by Luján et al 23…”

Exhaust Emissions Measurement of a Vehicle with Retrofitted LPG System

“…The aim of the research was to quantify the changes in the fuel of the same vehicle [51]. Several studies confirm that it makes sense to carry out tests and to measure emissions while actually driving was another type-approval test to take into account the impact of road profile, ambient conditions, and traffic situations [19,52].…”

Analysis of pollutant emissions and fuel consumption, during real driving cycles in different intake temperature scenarios

“…22 RDE test cycle in this paper was mainly obtained from a specific cycle performed on road, 23 but it had to be slightly modified to fulfill with the newest regulation. After that, conditions of the cycle have been reproduced in a test bench to eliminate the variations that many parameters as the weather, ambient pressure, 24,25 traffic, driver behavior that produces different dynamic solicitations, 26 road grade, 27 aftertreatment status or vehicle mileage can produce [28][29][30][31][32][33][34] as well as other issues that can appear which can spoil the test like DPF regeneration, traffic jams, etc. For example, different on road cycles that follow the same route, can have a high NOx emission dispersion, 35 and it is likely to find emissions differences of up to 24%.…”