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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.

Particle number (PN) emission limits were introduced in the European Union’s regulations for light-duty and heavy duty vehicles in the years 2011-2014. Since then, PN measurements have become a common practice in the automotive sector. Many studies showed that the current methodology, which counts particles >23 nm, misses a large fraction of particles for some engine technologies, such as port fuel injection vehicles or vehicles fueled with compressed natural gas (CNG). However, data for the latest technology vehicles are lacking. For this reason, we measured PN emissions >23 nm and >10 nm of >30 CNG, gasoline and diesel-fueled vehicles. Two systems were measuring in parallel from the full dilution tunnel; one with an evaporation tube and the other with a catalytic stripper. The PN emission levels spanned over three orders of magnitude depending on whether there was a particulate filter installed or not.

The aim of this paper is to analyse the results of regulated and unregulated emissions and carbon dioxide (CO2) emissions of passenger cars equipped with compression-ignition engines that meet the emission Euro 6d standards. Both test vehicles featured selective catalytic reduction (SCR) systems for control of oxides of nitrogen (NOx) and one vehicle also featured a passive NOx absorber (PNA). Research was performed using the current European Union exhaust emission test methods for passenger cars (Worldwide harmonized Light vehicles Test Procedures (WLTP)). Emission testing was performed on a chassis dynamometer, within a climatic chamber, at two different ambient temperatures: 23°C (i.e. Type I test) and -7°C (known as a Type VI test - currently not required for this engine type according to EU legislative requirements).

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).

European Union RDE (real driving emissions) legislation requires that new vehicles be subjected to emissions tests on public roads. Performing emissions testing outside a laboratory setting immediately raises the question of the impact of ambient conditions - especially temperature - on the results. In the spirit of RDE legislation, a wide range of ambient temperatures are permissible, with mathematical moderation (correction) of the results only permissible for ambient temperatures <0°C and >+30°C. Within the standard range of temperatures (0°C to +30°C), no correction for temperature is applied to emissions results and the applicable emissions limits have to be met. Given the well-known link between the thermal state of an engine and its emissions following cold start, ambient temperature can be of great importance in determining whether a vehicle meets emissions requirements during an RDE test.

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.

Vehicular ammonia emissions are currently unregulated, even though ammonia is harmful for a variety of reasons, and the gas is classed as toxic. Ammonia emissions represent a serious threat to air quality, particularly in urban settings; an ammonia emissions limit may be introduced in future legislation. Production of ammonia within the cylinder has long been known to be very limited. However, having reached its light-off temperature, a three-way catalyst can produce substantial quantities of ammonia through various reaction pathways. Production of ammonia is symptomatic of overly reducing conditions within the three-way catalyst (TWC), and depends somewhat upon the particular precious metals used. Emission is markedly higher during periods where demand for engine power is higher, when the engine will be operating under open-loop conditions.

Diesel (compression ignition, CI) engines are increasingly exploited in light-duty vehicles, due to their high efficiency and favorable characteristics. Limited work has been performed on CI cold-start emissions at low temperatures. This paper presents a discussion and a brief literature review of diesel cold-start emissions phenomena at low ambient temperatures and the results of tests performed on two European light-duty vehicles with Euro 5 CI engines. The tests were performed on a chassis dynamometer within an advanced climate-controlled test laboratory at BOSMAL Automotive Research and Development Institute, Poland to determine the deterioration in emission of gaseous (HC, CO, NOx, CO2) and solid (PM, PN) pollutants following the EU legislative test procedure (testing at 20°C to 30°C and at -7°C, performed over the NEDC). The tests revealed appreciable increases in emissions of regulated pollutants.

Spark ignition (SI) engines are susceptible to excess emissions at low ambient temperatures. Direct injection leads to the formation of particulate matter (PM), and direct injection spark ignition (DISI) engines should show greater PM emissions at low ambient temperatures. This study compares excess emissions of gaseous and solid pollutants following cold start at a low ambient temperature and the standard test temperature. Euro 5 passenger cars were tested on a chassis dynamometer within BOSMAL's climate-controlled test chamber, according to European Union legislation (−7°C over the urban driving cycle (UDC), and at 25°C). Two vehicles were also tested over the entire New European Driving Cycle (NEDC). Emissions of regulated compounds and carbon dioxide were analyzed; particulate emissions (both mass and number) were also measured, all using standard procedures.

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).

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.

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).

The paper evaluates the possibility of using different biodiesel blends (mixture of diesel fuel and Fatty Acid Methyl Esters) in modern Euro 4/ Euro 5 direct-injection, common-rail, turbocharged, light-duty diesel engines. The influence of different quantity of RME in biodiesel blends (B5, B20, B30) on the emission measurement of gaseous pollutants, such as: carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx), carbon dioxide (CO2) and particulate matter (PM) for light-duty-vehicle (LDV) during NEDC cycle on the chassis dynamometer as well as engine performance and reliability in engine dyno tests were analysed. All test results presented have been to standard diesel fuel. The measurement and analysis illustrate the capability of modern light-duty European diesel engines fueled with low and medium percentages of RME in biodiesel fuel with few problems.

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.

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.

Carbon dioxide (CO2) is one of the basic greenhouse gases and according to some opinions their influence upon warming the earth climate is significant. Acceptance of this prognosis has lead to worldwide legislative limitation covering all CO2 emitting engines. The paper reviews the relationship between CO2 emissions and fuel consumption in a range of automobiles (with SI and CI engines) presented for type approval over last four years (1996-1999). The paper presents an analysis of the results of an examination of the CO2 emission and the fuel consumption of more like 150 automotive vehicles (M1 and N1 categories), European, Japanese/Korean manufacturer and the US. The procedures used in the examination for approval in the presented scope have been described and several results of these examinations conducted in Poland in accordance with the requirements of the Regulations No. 101 ECE UNO (directive 93/116 EC) have been evaluated.

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).

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.

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.

This paper reviews the emissions from direct injection (DI) diesel engine in the initial period of controlled engine operation following start-up. The tests were undertaken in „cold start” mode (temperature of cooling water and lube oil equal to ambient temperature) and „warm start” mode* (after attaining a state of equilibrium). Both results were compared.