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Published byRobert Evans Modified over 8 years ago
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Questions on cycle representativeness (French position) EU – WLTP 17 th of September 2013
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WLTP cycle seems acceptable in its representativeness in terms of driving dynamics (databases have been developed for this purpose) and its modular design, identifying different driving phases and different categories of vehicles. However WLTC cycle, in its whole, seems globally not representative of uses of vehicles, notably in France, by the relative weight of urban conditions, rural and motorway, and by the average speeds resulting. This is also confirmed in the FIAT EcoDrive Data. Overall development of the cycle
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Analysis of the Fiat Ecodrive data study Focus on average speed
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Analysis of Fiat Ecodrive data (Further check of the results), slide 8 A number of vehicle/driver combinations are withdrawn from the analysis. Such a deletion is critical because it affects the real representativity of the driving situations.
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Analysis of Fiat Ecodrive data (p_stp vs v_ave), slide 16 WLTC average speed (46,5 km/h) is higher compared to Fiat Ecodrive average speed (39,8 km/h) and to other relevant data sources (see annex) Unlike Fiat Ecodrive distribution, the WLTC distribution isn’t uniform
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Analysis of Fiat Ecodrive data (Summary and conclusions), slide 59 The higher WLTC average speed is not explained for smaller cars in Fiat Ecodrive data : Indeed, for each available vehicle classes, Fiat Ecodrive data average speeds are much lower than WLTC data average speeds (4 to 10 km/h) The Fiat Ecodrive data doesn’t confirm the statistical data used for WLTC
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Summary Average speed, trip length and stop pourcentage of the WLTP seem not to be representative of real-life conditions. This unrepresentativeness seems not limited to France, as the average speeds recorded by different surveys do not differ fundamentally between European countries. Such an over-estimation of average speed, trip length and under-estimation of stop pourcentage, seems to lead to an under-estimation of fuel consumption. Other issues : Fuel consumption differences due to engine displacement and mass are minimized with WLTP compared to real life: it is linked to the cycle and not to the procedure (high speeds are over-represented). WLTC has a direct impact on future technology development choices (risk to reduce the real efficiency of technology).
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Impact on fuel consumption (Manufacturer data) Concerning WLTP fuel consumptions, we still observe differences with real-life conditions and higher for the highest fuel consumptions (up to -1,5 l/100 km) in an ideal situation, the slope should be flat and nearest to zero. Border conditions : Gasoline engines : 1,2 – 1,6 l with and without turbocharger Diesel engines : 1,4 – 2 l Vehicles : class A – C SUV Gearbox : manual and automatic -With and without stop and start WLTP
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Conclusions Consequence : Regarding fuel consumption measured with WLTP, risk to still have important differences with real-life conditions An important aim of WLTP was to solve those differences between homologation figures and real-life To conclude, France : would like to ensure the representativeness with real-life conditions of the actual cycle to other MS with robust data alerts the Commission and the other MS on the risk to implement a new cycle without solving the criticism made on NEDC
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Annex
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Relevant data sources in EU Source: literature 2, INRETS report LTE 9906
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