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Fatty Acid Methyl Ester (FAME) products derived from vegetable oils and animal fats are now widely used in European diesel fuels and their use will increase in order to meet mandated targets for the use of renewable products in road fuels. As more FAME enters the diesel pool, understanding the impact of higher FAME levels on the performance and emissions of modern light-duty diesel vehicles is increasingly important. Of special significance to Well-to-Wheels (WTW) calculations is the potential impact that higher FAME levels may have on the vehicle's volumetric fuel consumption. The primary objective of this study was to generate statistically robust fuel consumption data on three light-duty diesel vehicles complying with Euro 4 emissions regulations. These vehicles were evaluated on a chassis dynamometer using four fuels: a hydrocarbon-only diesel fuel and three FAME/diesel fuel blends containing up to 50% v/v FAME. One FAME type, a Rapeseed Methyl Ester (RME), was used throughout.

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.

Waste heat recovery based on an Organic Rankine Cycle is a technology proposed for the reduction of the fuel consumption of heavy-duty vehicles. This technology is currently not simulated by VECTO, the tool used in Europe to certify the fuel consumption and CO2 emissions of new heavy-duty vehicles. In this work, a class 5 lorry equipped with a prototype Organic Rankine Cycle system is tested on the chassis dyno during steady state and transient driving cycles, with the waste heat recovery enabled and disabled. The waste heat recovery system enabled a brake specific fuel consumption reduction of 3.1% over the World Harmonized Vehicle Cycle, 2.5% during the official EU Regional Delivery Cycle, and up to 6.5% at certain engine operating points during the fuel consumption mapping cycle. A model of the vehicle was created in VECTO based on the experimental data. The fuel consumption map of the engine with and without the Organic Rankine Cycle was derived from the steady-state experiments.

A vital element of any vehicle-certification test is the use of representative values for the vehicle resistance forces. In most certification procedures, including the WLTP recently adopted by the EU, the latter is achieved mainly through coast down tests. Subsequently, the resistance values measured are used for setting up the chassis-dyno resistances applied during the laboratory measurements. These reference values are obtained under controlled conditions, while a series of corrections are applied to make the test procedure more repeatable and reproducible. In real driving, the actual vehicle road loads are influenced by a series of factors leading to a divergence between the certified fuel consumption values, and the real-world ones. An approach of calculating representative road loads during on-road tests can help to obtain a more unobstructed view of vehicle efficiency and, when needed, confirm the officially declared road loads.

New heavy-duty vehicles are simulated with the Vehicle Energy Consumption Calculation Tool (VECTO) to certify their fuel consumption and CO2 emissions in the European Union. The vehicle manufacturer runs the simulation tool and requires the vehicle components' characteristics to simulate the vehicle over standardized mission profiles. The detailed component characteristics required to run the tool are not always publicly available. In this work, a simplified model was developed to predict the fuel consumption and CO2 emissions of heavy buses over the VECTO mission profiles. It requires only the basic vehicle properties as input, such as the air drag, tire rolling resistance, mass, drivetrain efficiency and auxiliary power use. The model was derived from detailed VECTO simulations of numerous variants of a diesel high floor bus, a diesel low floor bus and a CNG low floor bus.

Vegetable oils blended with diesel fuel are recognised as biofuels by the European legislation and their application is an interesting option for increasing the market share of biofuels. This paper presents results from a detailed study conducted on a Euro 3 compliant diesel passenger car and a high injection pressure test bench engine using 10% Cottonseed oil- 90% Diesel blends as fuel. The tests included fuel consumption and emissions measurements. Aim of the experimental analysis was to accurately evaluate the effect of biofuel application on a common rail engine. The measurement protocol included measurements of regulated emissions, fuel consumption and in-cylinder pressure at various operation modes. Results from the bench engine measurements are in line with those retrieved from the vehicle and indicate that the fuel tested presents good characteristics and that under certain conditions it can be applied as automotive fuel in a broader scale.

Reducing fuel consumption and emissions from road transport is a key factor for tackling global warming, promoting energy security and sustaining a clean environment. Several technical measures have been proposed in this aspect amongst which the application of low viscosity engine lubricants. Low viscosity lubricants are considered to be an interesting option for reducing fuel consumption (and CO2 emissions) throughout the fleet in a relatively cost effective way. However limited data are available regarding their actual “real-world” performance with respect to CO2 and other pollutant emissions. This study attempts to address the issue and to provide experimental data regarding the benefit of low viscosity lubricants on fuel consumption and CO2 emissions over both the type-approval and more realistic driving cycles.

Today most of the European member states offer diesel fuel which contains fatty acid methylesters (biodiesel) at a range between 0.5 to 5% vol. In order to meet longer term objectives, the mixing ratio is expected to rise up to 10% vol. in the years to come. The question therefore arises, how current engine technologies, which were not originally designed to operate on biodiesel blends, perform at this relatively high mixing ratio. A number of experiments were therefore performed over several steady-state operation modes, using a 10% vol. biodiesel blend (palm oil feedstock) on a light-duty common-rail Euro 3 engine. The experiments included measurement of the in-cylinder pressure during combustion, regulated pollutants emissions and fuel consumption. The analysis showed that the blends tested present good fuel characteristics. Combustion effects were limited but changes in the start of ignition and heat release rate could still be identified.

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.

Plug-in Hybrid Electric Vehicles (PHEVs) are one of the main technology options for reducing vehicle CO2 emissions and helping vehicle manufacturers (OEMs) to meet the CO2 targets set by different Governments from all around the world. In Europe OEMs have introduced a number of PHEV models to meet their CO2 target of 95 g/km for passenger cars set for the year 2021. Fuel consumption (FC) and CO2 emissions from PHEVs, however, strongly depend on the way they are used and on the frequency with which their battery is charged by the user. Studies have indeed revealed that in real life, with poor charging behavior from users, PHEV FC is equivalent to that of conventional vehicles, and in some cases higher, due to the increased mass and the need to keep the battery at a certain charging level.

This study investigates the impact of low concentration biodiesel blends on the regulated and polycyclic aromatic hydrocarbon (PAH) emissions from a modern passenger vehicle. The vehicle was Euro 4 compliant fitted with a direct injection common-rail diesel engine and a diesel oxidation catalyst. Emission and fuel consumption measurements were performed on a chassis dynamometer using constant volume sampling (CVS) technique, following the European regulations. All measurements were conducted over the type approval New European Driving Cycle (NEDC) and the real-traffic-based Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based, a palm-based, and a rapeseed oil-based biodiesel were blended with an ultra-low sulfur diesel at proportions of 10, 20, and 30% by volume. The experimental results revealed that emissions of PM, HC and CO decreased with biodiesel over most driving conditions.

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.

Until 2017 in Europe the Type Approval (TA) procedure for light duty vehicles for the determination of pollutant emissions and fuel consumption was based on the New European Driving Cycle (NEDC), a test cycle performed on a chassis dynamometer. However several studies highlighted significant discrepancies in terms of CO2 emissions between the TA test and the real world, due to the limited representativeness of the test procedure. Therefore, the European authorities decided to introduce a new, up-to date, test procedure capable to closer represent real world driving conditions, called Worldwide Harmonized Light Vehicles Test Procedure (WLTP). This work aims to analyze the effects of the new WLTP on vehicle CO2 emissions through both experimental and simulation investigations on two different Euro 5 vehicles, a petrol and a diesel car, representatives of average European passenger cars.

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.

In European Union (EU), new heavy-duty vehicles are simulated with the Vehicle Energy Consumption calculation TOol (VECTO) to certify their fuel consumption and CO2 emissions. VECTO will also be used to certify vehicles with hybrid-electric powertrains in all topological configurations from P0 to P4 parallel systems and series hybrids. A development version of VECTO able to simulate these configurations is already available and was used for this study. The study team collected measurement data from a specific P2 hybrid lorry, instrumented with wheel torque sensors, current and voltage sensors, fuel flow sensor and a PEMS device. The vehicle was tested on the chassis dyno and on the road, and a representative model was created in VECTO. The regional delivery certification cycle was simulated in VECTO in charge sustaining and full electric mode.