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The Particle Measurement Programme (PMP) developed an exhaust particle number measurement protocol that has been adopted by current light duty vehicle emission regulations in Europe. This includes thermal treatment of the exhaust aerosol to isolate solid particles only and a number counting device with a lower cutpoint of 23 nm to avoid measurement of smaller particles that may affect the repeatability of the measurement. In this paper, we examine a potential alternative to the PMP system, where the thermal treatment is replaced by a catalytic stripper (CS). This offers oxidation and not just evaporation of the volatile components. Alternative sampling systems, either fulfilling the PMP recommendations or utilizing a CS, have been explored in terms of their volatile particle removal efficiency. Tests have been conducted on diesel exhaust, diesel equipped with DPF and gasoline direct injection emissions.

Euro 5/6 light-duty vehicle emissions regulation introduced non-volatile particle number emission measurements. The particle number measurement system consists of a volatile removal unit followed by a particle number counter with a 50% cut-point diameter at 23 nm. The volatile removal unit must achieve a >99% concentration reduction of a monodisperse aerosol of tetracontane (CH 3 (CH 2 ) 38 CH 3 ) particles of diameter ≥30 nm with inlet concentration ≥10 4 cm −3 . In this paper the evaporation of tetracontane particles in the volatile removal unit is investigated theoretically. The temperature and the residence time in the evaporation tube are discussed, as well as the possibility of nucleation events of evaporated particles at the exit of the evaporation tube. In addition, sulfuric acid nucleation at the evaporation tube exit is analyzed. Theoretical calculations are, finally, compared to experimental data.

The selective catalytic reduction (SCR) of nitrogen oxides by ammonia is commonly applied as a method of exhaust aftertreatment for lean burn compression ignition (CI) engines. The catalytic reactor of an SCR system, like all catalytic emission control devices, is susceptible to partial deactivation as its operating time progresses. Long-term exposure of an SCR reactor to exhaust gas of fluctuating temperature and composition results in variations of the characteristics of its catalytically active layer. The aim of this study was to observe and investigate the variation of parameters characterizing the SCR reactor as a result of its ageing. Attention was paid to changes in ammonia storage capacity, selectivity of chemical reactions and maximum achievable NOx conversion efficiency. The experimental setup was a heavy duty (HD) Euro VI-compliant engine and its aftertreatment system (ATS). The setup was installed on a transient engine dyno instrumented with emission measurement devices.

The paper presents the test results relating to the influence of carbonate oxygenated additives to diesel fuel on exhaust emissions. Following the previous tests of glycol ethers (SAE Paper 2007-01-0069) and maleates (SAE Paper 2008-01-1813), the authors decided to use carbonates to obtain an even greater reduction in PM emissions. The significant effectiveness of carbonates on PM emission reduction was confirmed in tests performed by the authors. Diethyl carbonate was the most effective oxygenated compound with regard to PM emission reduction among all the 11 oxygenates which have been tested so far. Moreover, it is important to note that diethyl carbonate caused only a small increase in NOx emissions, thus it allowed for an essential improvement in the PM/NOx trade-off. A significant increase in the CO and HC emissions was, however, a negative effect of the use of carbonates.

The paper presents the test results of the influence of maleate oxygenated additives to diesel fuel on exhaust emissions. Following the previous tests of glycol ethers (SAE Paper 2007-01-0069), the authors decided to use maleates as oxygenates to obtain greater changes in PM/NOx trade-off than the changes obtained as a result of the use of glycol ethers. It was found that in the NEDC maleates at the same concentration as in the case of glycol ethers ensure more favourable changes of PM/NOx trade-off and, as a matter of fact, caused greater reduction in PM emissions without the growth of NOx emissions, however, at the cost of CO and HC emissions. The tests performed in the FTP-75 confirmed a significantly weaker influence of maleates, both positive (PM) and negative (CO, HC) than in the NEDC. They did not find in both cycles any influence of maleates at the tested concentration upon fuel consumption and CO2 emissions.

In the year 2005, the EURO IV fuel specification came into effect and the requirements for diesel fuel properties have become even more stringent. In this way, the potential of diesel fuel for emissions reduction has already been to a large extent exploited and the most emissions-sensitive fuel parameters can now be changed in a narrow range only. The shortfall in NOx and PM emissions control in diesel engines is, however, so great that more drastic fuel changes will be needed. One of the most promising fuel modifications for exhaust emissions control seems to be oxygenated additives. The objective of the study described in this paper was to analyze under transient conditions the influence of synthetic oxygenated fuel additives on exhaust emissions. The tests were conducted on a Euro IV passenger car. Six oxygenated additives were tested over the New European Driving Cycle (NEDC).

Research on the influence of oxygenated diesel fuels on the PM/NOx emission trade-off was carried out with use of 11 different synthetic oxygenated compounds, representing 3 chemical groups (glycol ethers, maleates, carbonates). Each of oxygenates were evaluated as a fuel additive at a concentration of 5% v/v in the same base diesel fuel. The tests were conducted on a passenger car equipped with a common rail turbocharged diesel engine over the European cycle NEDC and US FTP-75 cycle. All the tested oxygenates caused a reduction in PM emissions and most of them caused a certain increase in NOx emissions. The changes in emissions depended on the oxygenate type and cycle. In general, the favorable and unfavorable influence of oxygenated compounds was more intensive during the NEDC, which is a softer and less transient cycle than the FTP-75. The most favorable changes in the PM/NOx emission trade-off were obtained for maleates and carbonates.

Ethanol has long been a fuel of considerable interest for use as an automotive fuel in spark ignition (SI) internal combustion engines. In recent years, concerns over oil supplies, sustainability and geopolitical factors have lead multiple jurisdictions to mandate the blending of ethanol into standard gasoline. The impact of blend ethanol content on gaseous emissions has been widely studied; particulate matter emissions have received somewhat less attention, despite these emissions being regulated in the USA. Currently, in the EU particulate matter emissions from SI engines are partially regulated - only vehicles featuring direct injection SI engines are subject to emissions limits. A range of experiments was conducted to determine the impact of fuel ethanol content on the emissions of solid pollutants from Euro 5 passenger cars.

Due to limited fossil fuel resources and a need to reduce anthropogenic CO₂ emissions, biofuel usage is increasing in multiple markets. Ethanol produced from the fermentation of biomass has been of interest as a potential partial replacement for petroleum for some time; for spark-ignition engines, bioethanol is the alternative fuel which is currently of greatest interest. At present, the international market for ethanol fuel consists of E85 fuel (with 85 percent ethanol content), as well as lower concentrations of ethanol in petrol for use in standard vehicles (E5, E10). The impact of different petrol-ethanol blends on exhaust emissions from unmodified vehicles remains under investigation. The potential for reduced exhaust emissions, improved security of fuel supply and more sustainable fuel production makes work on the production and usage of ethanol and its blends an increasingly important research topic.

The use of biofuels (biodiesel and gasoline-alcohol blends) in vehicle powertrains has grown in recent years in European Union, the United States, Japan, India, Brazil and many other countries due to limited fossil fuel sources and necessary reduction of anthropogenic CO2 emissions. European car manufacturers have approved up to 5 percent of biodiesel blend in diesel fuel (B5 biodiesel blend) which meets European fuel standards EN 14214 and EN 590. The goal for research is to achieve higher biodiesel content in diesel fuel B10 and B20, without resorting to larger diesel engines and fuel feed system modernization. This paper evaluates the possibility of using higher FAME content in biodiesel blends (mixture of diesel fuel and Fatty Acid Methyl Esters) in modern Euro 4 vehicle with direct-injection, common-rail and turbocharged light-duty diesel engine with standard engine ECU calibration and standard injection equipment (not tuned for biodiesel).

The investigations into the emissions from light-duty vehicles have been carried out on a chassis dynamometer (NEDC test in Europe and FTP75 test in the US). Such tests do not entirely reflect the real road conditions and that is why we should analyze the correlation of the laboratory versus on-road test results. The paper presents the on-road test results obtained in an urban and extra urban cycles. For these measurements a portable SEMTECH DS analyzer by SENSORS has been used. The device is an analyzer enabling an on-line measurement of the emission gases concentration in a real driving cycle under real road conditions. The road tests were performed on road portions of several kilometers each. The obtained results were compared with the results obtained for the same vehicle during the NEDC test on a chassis dynamometer. The comparative analysis was performed including the urban and extra-urban cycles.

Recently, a particle number (PN) limit was introduced in the European light-duty vehicles legislation. The legislation requires measurement of PN, and particulate mass (PM), from the full dilution tunnel with constant volume sampling (CVS). Furthermore, PN measurements will be introduced in the next stage of the European Heavy-Duty regulation. Heavy-duty engine certification can be done either from the CVS or from a partial flow dilution system (PFDS). For research and development purposes, though, measurements are often conducted from the raw exhaust, thereby avoiding the high installation costs of CVS and PFDS. Although for legislative measurements requirements exist regarding sampling and transport of the aerosol sample, such requirements do not necessarily apply for raw exhaust measurements. Thus, measurement differences are often observed depending on where in the experimental set up sampling occurs.

The aim of this paper was to explore the influence of CNG fuel on emissions from light-duty vehicles in the context of the new Euro 6 emissions requirements and to compare exhaust emissions of the vehicles fueled with CNG and with gasoline. Emissions testing was performed on a chassis dynamometer according to the current EU legislative test method, over the New European Driving Cycle (NEDC). Additional tests were also performed on one of the test vehicles over the World Harmonized Light Vehicles Test Cycle (WLTC) according to the Global Technical Regulation No. 15 test procedure. The focus was on regulated exhaust emissions; both legislative (CVS-bag) and modal (continuous) analyses of the following gases were performed: CO (carbon monoxide), THC (total hydrocarbons), CH4 (methane), NMHC (non-methane hydrocarbons), NOx (oxides of nitrogen) and CO2 (carbon dioxide).

Ethanol has a long history as an automotive fuel and is currently used in various blends and formats as a fuel for spark ignition engines in many areas of the world. The addition of ethanol to petrol has been shown to reduce certain types of emissions, but increase others. This paper presents the results of a detailed experimental program carried out under standard laboratory conditions to determine the influence of different quantities of petrol-ethanol blends (E5, E10, E25, E50 and E85) on the emission of regulated and unregulated gaseous pollutants and particulate matter. The ethanol-petrol blends were laboratory tested in two European passenger cars on a chassis dynamometer over the New European Driving Cycle, using a constant volume sampler and analyzers for quantification of both regulated and unregulated emissions.

This paper discusses the importance of the inclusion of emissions from the cold start event during legislative on-road tests on passenger cars (RDE - real driving emissions tests conducted under real-world driving conditions, as defined by EU legislation). Results from a recently-registered gasoline-powered vehicle are presented, with the main focus on the comparison of exhaust emission results: excluding/including the cold start during the initial phase of the RDE test. Cold start is the most challenging aspect of emissions control for vehicles with spark ignition engines and the inclusion of the cold start event in RDE test procedure has wide-ranging implications both for the testing process and compliance with RDE legislation via optimisation of aftertreatment systems and the engine calibration. In addition to some theoretical arguments, the results of an RDE-compliant test performed using the aforementioned procedures are presented.

The aim of this paper is to analyze the quantitative impact of fuel sulfur content on particulate oxidation catalyst (POC) functionality, focusing on soot emission reduction and the ability to regenerate. Studies were conducted on fuels containing three different levels of sulfur, covering the range of 6 to 340 parts per million, for a light-duty application. The data presented in this paper provide further insights into the specific issues associated with usage of a POC with fuels of higher sulfur content. A 48-hour loading phase was performed for each fuel, during which filter smoke number, temperature and back-pressure were all observed to vary depending on the fuel sulfur level. The Fuel Sulfur Content (FSC) affected also soot particle size distributions (particle number and size) so that with FSC 6 ppm the soot particle concentration was lower than with FSC 65 and 340, both upstream and downstream of the POC.

This paper presents a novel partial flow sampling system for the characterization of airborne exhaust particle emissions. The sampled aerosol is first conditioned in a porous dilutor and then subsequent ejector dilutors are used to decrease its concentration to the range of the instrumentation used. First we examine the sensitivity of aerosol properties to boundary sampling conditions. This information is then used to select suitable sampling parameters to distinguish both the nucleation and the accumulation mode. Selecting appropriate sampling parameters, it is demonstrated that a distinct nucleation mode can be formed and measured with different instruments. Using these parameters we examine the performance of the system over transient vehicle operation. Additionally, we performed calculations of particle losses in the various components of the system which are then used to correct signals from the instruments.

Direct injection gasoline engines have been gaining popularity for passenger car applications, particularly in the EU. It is well known that emissions of particulate matter are an inherent disadvantage of spark ignition engine with direct injection. Direct injection of gasoline can lead to the formation of substantial numbers of particulates, a proportion of which survive to be emitted from the vehicle's exhaust. EU legislation limits particle mass (PM) emissions; particle number (PN) is soon to be limited, although an opt-out means that dedicated filters will not be required immediately. A range of tests were conducted on a pool of Euro 5 passenger cars in BOSMAL's climate controlled emissions laboratory, using EU legislative test methodology. In addition, further measurements were performed (particle size distribution, tests at multiple ambient temperatures).

By early 2007, all major manufacturers of light-duty diesel vehicles are marketing models equipped with diesel particulate filters (DPFs). However, there is still a lack of understanding of the particles emitted when the DPF undergoes regeneration. This paper focuses on measuring particle emissions of a representative light-duty diesel vehicle equipped with DPF and employing a fuel-borne catalyst (FBC) to aid regeneration. Particulate Matter (PM) and non-volatile particle number emissions are measured throughout testing according to the Particle Measurement Programme (PMP) proposals. In addition, an Engine Exhaust Particle Sizer (EEPS) connected directly to the CVS is used to give real time size distributions of both volatile and non-volatile particles. The paper focuses on particle emissions during regenerating New European Driving Cycles (NEDCs).

Due to the stringent emission standards set worldwide, particulate matter (PM) emissions from diesel vehicles have been significantly curtailed in the last decade, and are expected to be reduced even further in the future. This evolution has brought forward two main issues: whether PM emissions should only be regulated for diesel vehicles and whether gasoline powered vehicles can be further neglected from PM emission inventories. This paper addresses these issues comparing the characteristics of particle emissions from a current diesel passenger car, a gasoline one and two small two-wheelers. It is shown that the gasoline car is a negligible source of particle emissions while the two-wheelers may be even more significant particle sources than the diesel car.