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The effect of “Start & Stop” and “Gear Shift Indicator” - two widespread fuel saving technologies - on fuel consumption and particle emissions of a Euro 5 passenger car is evaluated in this paper. The vehicle was subjected to a series of different driving cycles, including the current (NEDC) and future (WLTC) cycles implemented in the European type approval procedure at cold and hot start condition and particle number was measured with an AVL Particle Counter. In addition, we have utilized two Pegasor Particle Sensor units positioned in different locations along the sampling line to assess the impact of the sampling location on the particle characteristics measured during highly transient events. The results showed that the particle number emission levels over the WLTC were comparable to the NEDC ones, whereas NOx emissions were more than twofold higher. Both fuel saving technologies can lead to reduced fuel consumption and, subsequently CO2 emissions, in the order of 5%.

The upcoming Euro 7 regulation introduces the concept of continuous On-Board (emission) Monitoring (OBM), while On-Board Fuel/Energy Consumption Monitoring (OBFCM) is already an integral part of modern vehicles. The current work aims to assess whether on-board data could provide sufficient information to characterize real-world vehicle performance and emissions. Nine Euro 6d-ISC-FCM passenger cars were used, covering a wide range of powertrain technologies, from conventional gasoline and diesel to hybrid (HEV) and plug-in hybrid (PHEV) electric vehicles. Three vehicles were thoroughly tested in the laboratory and on the road, aiming at evaluating in detail the on-board data monitoring system. The evaluation concerned OBFCM device recordings of fuel consumed and distance travelled, as well as tailpipe NOx emissions and exhaust mass flow rate.

This study examines the effects of neat soy-based biodiesel (B100) and its 50% v/v blend (B50) with low sulphur automotive diesel on vehicle PAH emissions. The measurements were conducted on a chassis dynamometer with constant volume sampling (CVS) according to the European regulated technique. The vehicle was a Euro 2 compliant diesel passenger car, equipped with a 1.9 litre common-rail turbocharged direct injection engine and an oxidation catalyst. Emissions of PAHs, nitro-PAHs and oxy-PAHs were measured over the urban phase (UDC) and the extra-urban phase (EUDC) of the type approval cycle (NEDC). In addition, for evaluating realistic driving performance the non-legislated Artemis driving cycles (Urban, Road and Motorway) were used. Overall, 12 PAHs, 4 nitro-PAHs, and 6 oxy-PAHs were determined. The results indicated that PAH emissions exhibited a reduction with biodiesel during all driving modes.

The successful design and especially the control of the SCR system is a challenging process that can be supported by the application of simulation tools. As a first step, we employ physico-chemically informed ‘off-line’ models that are calibrated with the help of targeted small- and full-scale tests. Despite their high level of sophistication, this SCR model is able to be integrated in a control-oriented simulation software platform and connected to other powertrain simulation blocks. The target is to use this simulation platform as a virtual environment for the development and optimization of SCR control strategies. The above process is demonstrated in the case of a passenger car SCR. The model is calibrated at both fresh and aged catalyst condition and validated using experimental data from the engine bench under a wide variety of operating conditions. Next, the calibrated model was coupled with embedded control models, developed for Euro 6 passenger car powertrains.

This paper presents an overview of the results on heavy duty engines collected in the “PARTICULATES” project, which aimed at the characterization of exhaust particle emissions from road vehicles. The same exhaust gas sampling and measurement system as employed for the measurements on light duty vehicles [1] was used. Measurements were made in three labs to evaluate a wide range of particulate properties with a range of heavy duty engines and fuels. The measured properties included particle number, with focus separately on nucleation mode and solid particles, particle active surface and total mass. The sample consisted of 10 engines, ranging from Euro-I to prototype Euro-V technologies. The same core diesel fuels were used as in the light duty programme, mainly differentiated with respect to their sulphur content. Additional fuels were tested by some partners to extend the knowledge base.

This paper presents an overview of the results on light duty vehicles collected in the “PARTICULATES” project which aimed at the characterization of exhaust particle emissions from road vehicles. A novel measurement protocol, developed to promote the production of nucleation mode particles over transient cycles, has been successfully employed in several labs to evaluate a wide range of particulate properties with a range of light duty vehicles and fuels. The measured properties included particle number, with focus separately on nucleation mode and solid particles, particle active surface and total mass. The vehicle sample consisted of 22 cars, including conventional diesels, particle filter equipped diesels, port fuel injected and direct injection spark ignition cars. Four diesel and three gasoline fuels were used, mainly differentiated with respect to their sulfur content which was ranging from 300 to below 10 mg/kg.

The pressure for compact and efficient deNO systems has led to increased interest of incorporating SCR coatings in the DPF walls. This technology could be very attractive especially if high amounts of washcoat loadings could be impregnated in the DPF porous walls, which is only possible with high porosity filters. To counterbalance the filtration and backpressure drawbacks from such high porosity applications, the layered wall technology has already been proposed towards minimizing soot penetration in the wall and maximizing filtration efficiency. In order to deal with the understanding of the complex interactions in such advanced systems and assist their design optimization, this paper presents an advanced modeling framework and selected results from simulation studies trying to illustrate the governing phenomena affecting deNO performance and passive DPF regeneration in the above combined systems.

It is commonly accepted that future powertrains will be based to a large extent on hybrid architectures, in order to optimize fuel efficiency and reduce CO₂ emissions. Hybrid operation is typically achieved with frequent engine start-and-stops during real-world as well as during the legislated driving cycles. The cooling of the exhaust system during engine stop may pose problems if the substrate temperature drops below the light-off temperature. Therefore, the design and thermal management of after-treatment systems for hybrid applications should consider the 3-dimensional heat transfer problem carefully. On the other hand, the after-treatment system calculation in the concept design phase is closely linked with engine calibration, taking into account the hybridization strategy. Therefore, there is a strong need to couple engine simulation with 3d aftertreatment predictions.

Modern diesel vehicles utilize two technologies, one fuel based and one hardware based, that have been motivated by recent European legislation: diesel fuel blends containing Fatty Acid Methyl Esters (FAME) and Diesel Particulate Filters (DPF). Oxygenates, like FAME, are known to reduce PM formation in the combustion chamber and reduce the amount of soot that must be filtered from the engine exhaust by the DPF. This effect is also expected to lengthen the time between DPF regenerations and reduce the fuel consumption penalty that is associated with soot loading and regeneration. This study investigated the effect of FAME content, up to 50% v/v (B50), in diesel fuel on the DPF regeneration frequency by repeatedly running a Euro 5 multi-cylinder bench engine over the European regulatory cycle (NEDC) until a specified soot loading limit had been reached.

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.

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.

Cyclic combustion variability (CCV) is an undesirable characteristic of spark ignition (SI) engines, and originates from variations in gas motion and turbulence, as well as from differences in mixture composition and homogeneity in each cycle. In this work, the cycle to cycle variability on combustion and emissions is experimentally investigated on a high-speed, port fuel injected, spark ignition engine. Fast response analyzers were placed at the exhaust manifold, directly downstream of the exhaust valve of one cylinder, for the determination of the cycle-resolved carbon monoxide (CO) and nitric oxide (NO) emissions. A piezoelectric transducer, integrated in the spark-plug, was also used for cylinder pressure measurement. The impact of engine operating parameters, namely engine speed, load, equivalence ratio and ignition timing on combustion and emissions variability, was evaluated.

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.

Efforts to develop a sensor for on-board diagnostics (OBD) of diesel vehicles are intensive as diesel particulate filters (DPFs) have become widespread around the world. This study presents a novel sensor that has been successfully tested for OBD diagnosis of damaged DPFs. The sensor is based on the "escaping current" technique. Based on this, a sample of exhaust gas is charged by a corona-ionized flow and is pumped by an ejector dilutor built in the sensor's construction. While the majority of ions return to the grounded sensor's body, a small quantity is lost with the charged particles exiting the sensor. This "escaping current" is a measurement of the particle concentration in the exhaust gas. Such a sensor has been developed and tested in real-exhaust of a diesel car and a diesel engine. The sensor provides high resolution (1 Hz, 0.3 s response time) and high sensitivity superseding OBD requirements. The sensor was used on an engine to monitor the efficiency of damaged DPFs.

Two models for the forecast of road traffic emissions, independently developed in parallel, are comparatively presented and assessed: EPROG developed by BMW and enlarged by VDA for a national application (Germany) and FOREMOVE, developed for application on European Community scale. The analysis of the methodological character of the two algorithms proves that the models are fundamentally similar with regard to the basic calculation schemes used for the emissions. The same holds true as far as the significant dependencies of the emission factors, and the recognition and incorporation of the fundamental framework referring to traffic important parameters (speeds, mileage and mileage distribution etc) are concerned.

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.

The present work investigates a number of recalibration possibilities of a common rail turbocharged diesel engine, aiming at the improvement of its emissions performance and fuel consumption (FC), with Hydrotreated Vegetable Oil (HVO). Initially, steady-state experimental data with nominal engine settings revealed HVO benefits as a drop-in fuel. Under these conditions, pure HVO results in lower engine-out PM emissions, lower CO2 emissions, and lower mass-based FC, while the respective NOx emissions present a mixed trend. In mid loads and speeds NOx emissions of HVO are lower while at higher loads and speeds are slightly higher compared to conventional diesel. At a second step, a combustion model was developed, in order to investigate the possible re-adjustments of IT (Injection Timing) and EGR (Exhaust Gas Recirculation) settings in order to exploit HVO’s properties for further reduction of emissions and FC.

Certain diesel fuel specification properties are considered to be environmental parameters according to the European Fuels Quality Directive (FQD, 2009/EC/30) and previous regulations. These limits included in the EN 590 specification were derived from the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) which was carried out in the 1990’s on diesel vehicles meeting Euro 2 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. In addition, no significant work has been conducted since to investigate whether relaxing these limits would give rise to performance or emissions debits or fuel consumption benefits in more modern vehicles. The objective of this test programme was to evaluate the impact of specific diesel properties on emissions and fuel consumption in Euro 4, Euro 5 and Euro 6 light-duty diesel vehicle technologies.

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.

To meet future stringent emission regulations such as Euro6, the design and control of diesel exhaust after-treatment systems will become more complex in order to ensure their optimum operation over time. Moreover, because of the strong pressure for CO₂ emissions reduction, the average exhaust temperature is expected to decrease, posing significant challenges on exhaust after-treatment. Diesel Oxidation Catalysts (DOCs) are already widely used to reduce CO and hydrocarbons (HC) from diesel engine emissions. In addition, DOC is also used to control the NO₂/NOx ratio and to generate the exothermic reactions necessary for the thermal regeneration of Diesel Particulate Filter (DPF) and NOx Storage and Reduction catalysts (NSR). The expected temperature decrease of diesel exhaust will adversely affect the CO and unburned hydrocarbons (UHC) conversion efficiency of the catalysts. Therefore, the development cost for the design and control of new DOCs is increasing.