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Due to the diversity of Heavy Duty Vehicles (HDV), the European CO2 and fuel consumption monitoring methodology for HDVs will be based on a combination of component testing and vehicle simulation. In this context, one of the key input parameters that need to be accurately defined for achieving a representative and accurate fuel consumption simulation is the vehicle's aerodynamic drag. A highly repeatable, accurate and sensitive measurement methodology was needed, in order to capture small differences in the aerodynamic characteristics of different vehicle bodies. A measurement methodology is proposed which is based on constant speed measurements on a test track, the use of torque measurement systems and wind speed measurement. In order to support the development and evaluation of the proposed approach, a series of experiments were conducted on 2 different trucks, a Daimler 40 ton truck with a semi-trailer and a DAF 18 ton rigid truck.

The European Union road transport CO2 emissions regulation foresees mandatory targets for passenger vehicles. However, several studies have shown that there is a divergence between official and real-world values that could range up to 40% compared to the NEDC reference value. The introduction of the Worldwide Harmonized Test Protocol (WLTP) limited this divergence, but it is uncertain whether it can adequately address the problem, particularly considering future evolutions of vehicle technology. In order to address this issue, the recent EU CO2-standards regulation introduces the monitoring of on-road fuel consumption and subsequently CO2 emissions by utilizing On-Board Fuel Consumption Meters (OBFCM). In the near future, all vehicles should provide instantaneous and lifetime-cumulative fuel consumption signals at the diagnostics port. Currently, the fuel consumption signal is not always available.

Heavy-duty vehicles (HDVs) account for some 5% of the EU’s total greenhouse gas emissions. They present a variety of possible configurations that are deployed depending on the intended use. This variety makes the quantification of their CO2 emissions and fuel consumption difficult. For this reason, the European Commission has adopted a simulation-based approach for the certification of CO2 emissions and fuel consumption of HDVs in Europe; the VECTO simulation software has been developed as the official tool for the purpose. The current study investigates the impact of various technologies on the CO2 emissions of European trucks through vehicle simulations performed in VECTO. The chosen vehicles represent average 2015 vehicles and comprised of two rigid trucks (Class 2 and 4) and a tractor-trailer (Class 5), which were simulated under their reference configurations and official driving cycles.

Following its commitment to reduce CO2 emissions from road transport in Europe, the European Commission has launched the development of a new methodology for monitoring CO2 emissions from heavy-duty vehicles (HDV). Due to the diversity and particular characteristics of the HDV sector it was decided that the core of the proposed methodology will be based on a combination of component testing and vehicle simulation. A detailed methodology for the measurement of each individual vehicle component of relevance and a corresponding vehicle simulation is being elaborated in close collaboration with the European HDV manufacturers, component suppliers and other stakeholders. Similar approaches have been already adopted in other major HDV markets such as the US, Japan and China. In order to lay the foundations for the future HDV CO2 monitoring and certification software application, a new vehicle simulation software was developed, Vehicle Energy Consumption calculation Tool (henceforward VECTO).

Gas-operated vehicles powered by natural gas (NG) or other gaseous fuels such as liquefied petroleum gas (LPG), are seen as a possible option for curbing CO₂ emissions, fuel consumption and operating costs of goods and passenger transport. Initiatives have been adopted by various public organizations in Europe and abroad in order to introduce gas-fueled vehicles in their fleets or use retrofit fueling systems in existing ones. In this study a retrofit dual fuel (diesel-gas) fuelling system was investigated as a potential candidate technology for city bus fleets. The system is marketed under the commercial name d-gid. It is a platform developed by the company Ecomotive Solutions for the control and management of a diesel engine fuelled with a mixture of gaseous fuels. In order to assess its environmental and cost effectiveness the system was tested on a Volvo city bus. The tests were performed on an HDV chassis dyno under various driving conditions.

The paper describes the development of a modelling approach to simulate the effect of the new Worldwide harmonized Light duty Test Procedure (WLTP) on the certified CO2 emissions of light duty vehicles. The European fleet has been divided into a number of segments based on specific vehicle characteristics and technologies. Representative vehicles for each segment were selected. A test protocol has been developed in order to generate the necessary data for the validation of the vehicle simulation models. In order to minimize the sources of uncertainty and the effects of flexibilities, a reference “template model” was developed to be used in the study. Subsequently, vehicle models were developed using AVL Cruise simulation software based on the above mentioned template model. The various components and sub-modules of the models, as well as their input parameters, have been defined with the support of the respective OEMs.

The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. Any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require generic inputs or reconstructing realistic component input data. The current study attempts to address this issue by developing a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10.