How exactly do you perform your tests, in the lab and on the road?
Prior to laboratory testing, we perform a coast-down test on an outdoor test track to determine a vehicle’s driving resistance, which is used to calibrate the chassis dynamometer in the laboratory. The vehicle is then driven over the WLTP, considering both cold and hot starts, and over steady-points, where the engine runs at specific operating points.
For the on-road testing, a Portable Emissions Measurement System (PEMS) is mounted on the vehicle, which is connected to the exhaust pipe and measures CO2 concentration. The vehicle is driven over an RDE regulation-compliant route around the Thessaloniki area.
How are the values displayed on the MILE21 website derived?
The fuel consumption values on the website are a prediction. The prediction is made based on three main variables:
- the fuel the vehicle runs on;
- the vehicle mass (mass in running order);
- the year of manufacture. This is done to factor in the trend of improved drivetrain efficiencies over the years.
The relationship between these variables and the fuel consumption of passenger cars was derived by regression analysis based on a large database of real-world fuel consumption data of Dutch drivers, over the period 2004 – now. Over time, the model can be refined by considering other driving conditions, such as outside temperature or elevation, and/or by using monitoring data and data reported by users of this website (functionality forthcoming).
Which external data sources will be considered in the project?
Vehicles’ type-approval data will be obtained from a recognised external data provider as well as, in the case of RDE data, from manufacturers directly. We aim to include third-party on-road emissions data to complement real-world fuel consumption estimates produced internally, thereby improving consumer information.
How does MILE21 collect the additional data shown on this website?
The initial vehicle data integrates type-approval data and third-party on-road measurements. MILE21 also collects additional data by making use of On-Board Diagnostics (OBD) readers that are deployed in a series of vehicles in several European countries. This data is then transmitted to the MILE21 platform, where a series of algorithms calculate the vehicle’s real-world fuel consumption.
What specific instruments does MILE21 use to collect data?
MILE21 uses OBD readers, which are devices that are plugged into, and read data directly from, the vehicle. This data includes a series of parameters that are transmitted via Wi-Fi or 3/4G to the MILE21 platform. These parameters are used to calculate fuel consumption. According to regulation, after 2020 all new vehicles must be equipped with a fuel flow meter which will provide fuel consumption values directly from the OBD.
How do you harmonise all the collected data?
The information collected from measurements is used to refine the mathematical base model. Self-reported fuel consumption data is used for adjustments of values for individual vehicle models. If inconsistencies occur between the general values and individual results, the deviations could be investigated if the individual owner is interested.
Where can I find more information about the regression-analysis-based models employed in the project?
The model description will be published in May 2019 in a TNO report for MILE21.
Do you only use regression analysis-based models, or have you also implemented other model-types?
Initially, MILE21 will use regression-based models that utilise real-world data to calculate fuel consumption values. A further expansion of the models may use obtained data to calibrate physical models that can simulate fuel consumption values for any given situation for a predetermined route.