Exhaust Gas Aftertreatment Research Articles

The Activation of Oxygen Species on the Pt/CeO2 Catalyst by H2 for NO Oxidation

The Pt/CeO2 catalyst has attracted significant attention due to its exceptional performance in NO oxidation. This study comprehensively examines the effects of calcination temperature and H2 pretreatment on the structure and activity of the Pt/CeO2 catalyst. Experimental findings indicate that the calcination temperature significantly affects the catalyst’s redox performance, thereby modulating its efficacy in NO oxidation reactions. H2 pretreatment facilitates the creation of oxygen vacancies on the catalyst, assisted by the reduction in PtOx to Pt, enhancing the formation of activated oxygen and thereby improving NO oxidation. This study offers valuable insights into the design and optimization of Pt/CeO2 catalysts for environmental applications, particularly in the development of exhaust gas after-treatment technologies.

Development and Performance Evaluation Experiment of a Device for Simultaneous Reduction of SOx and PM

Mitigating air pollutants such as SOx and PM emitted from ships is an important task for marine environmental protection and improving air quality. To address this, exhaust gas after-treatment devices have been introduced, but treating pollutants like SOx and PM individually poses challenges due to spatial constraints on ships. Consequently, a Total Gas Cleaning System (TGCS) capable of simultaneously reducing sulfur oxides and particulate matter has been developed. The TGCS combines a cyclone dust collector and a wet scrubber system. The cyclone dust collector is designed to maintain a certain distance from the bottom of the wet scrubber, allowing exhaust gases entering from the bottom to rise as sulfur oxides are adsorbed. Additionally, the exhaust gases descending through the space between the cyclone dust collector and the wet scrubber collide with the scrubbing solution before entering the bottom of the wet scrubber, facilitating the absorption of SOx. In this study, the efficiency of the developed TGCS was evaluated, and the reduction effects based on design parameters were investigated. Furthermore, the impact of this device on ship engines was analyzed to assess its practical applicability. Experimental results showed that increasing the volume flow rate of the cleaning solution enhanced the PM reduction effect. Particularly, when the height of the Pall ring was 1000 mm and the volume flow rate was 35 L/min, the sulfur oxide reduction effect met the standards for Sulfur Emission Control Areas (SECA). Based on these findings, suggestions for effectively controlling atmospheric pollutants from ships were made, with the expectation of contributing to the development of systems combining various after-treatment devices.

Challenges and Solutions to Meet the Euro 7 NOx Emission Requirements for Diesel Light-Duty Commercial Vehicles

AbstractThe improvement of air quality requires a further reduction of pollutant emissions, especially in urban areas. The Euro 7 regulations aim at the development of a new generation of internal combustion engine vehicles capable of achieving ultra-low pollutant emissions under demanding, real-world operating conditions. They introduce new technical challenges in the holistic design of a vehicle’s powertrain and emission control system. To identify these, four real-world Euro 7 driving scenarios are investigated, covering demanding urban, highway and mountain driving situations. Technical solutions are then presented to address these challenges and ensure compliance with the Euro 7 emission requirements as set out in the latest regulation proposal of the European Commission. The study focuses on the NOx emissions of an N1 Class III light commercial vehicle with 3.5 t mass and a P2 diesel mild-hybrid powertrain. To ensure emission compliance, a Euro 6e exhaust gas aftertreatment system with enlarged catalysts is combined with NOx raw emission improvements. For low-load cold starts, a 4-kW electric heater in the exhaust system is considered in addition to a 2-l DOC and a 6-l DPF with SCR coating. For high-load cycles with high raw emissions, a 10-l underfloor SCR is considered to ensure the necessary deNOx performance.

An experimental study on aging effects of fuel-cut events including sound optimized torque reduction on modern three-way catalysts

Continuously increasing country-specific emission standards for passenger vehicles demand additional development steps in complex exhaust gas aftertreatment systems for a more effective reduction of harmful gases. The efficiency of the aftertreatment system declines over its lifecycle due to specific load profiles and other boundary conditions, resulting in increasing emissions over vehicle mileage. As a result, the durability of the exhaust system becomes more important. Fuel cut is an intended, temporary interruption of the fuel supply of modern combustion engines of passenger cars to reduce fuel consumption and emissions. During this fuel reduction event, unconsumed oxygen of rich and cool fresh air is introduced to the combustion chamber and to the exhaust system. Besides a catalyst cool down, oxidation effects are provoked by enhanced oxygen reactions processes within the catalyst’s washcoat and surface layers. In this publication, specific aging cycles with a variation of fuel-cut programs were examined on their effects on a modified modern eight-cylinder turbo-charged engine, especially on their oxidation effects correlating to catalyst aging. Light-off curves and conversion heat maps were used to evaluate possible damaging impacts of fuel-cut events on the aging behavior of the catalyst systems. Results indicate that higher frequency of fuel-cut events results in a reduced catalyst conversion efficiency, whereas thermal sintering might be reduced due to overall lower temperature load. Temporary oxidation processes on catalyst’s surfaces occur only in a short timespan after changing the air fuel ratio to lean, resulting in a weaker thermal sintering during longer fuel-cut events. Sound optimized torque reduction functions, used in sports cars for a better drivability and powertrain response, exhibit a stronger aging influence due to additional thermal shock effects on the catalysts front face, as demonstrated via optical infrared sensor technology during catalyst aging cycles on the modified engine bench setup. A theoretical calculation of aging processes as a combination of thermal sintering by Arrhenius equation as well as oxidation process is discussed to describe an aging classification induced via oxidation processes. Additional physisorption measurements of different catalyst probes support the results which indicate the direction of future experimental approaches.

Study on the effect of wet scrubbing technique on emissions in a dual fuel engine operating with diesel and hydrogen.

Reducing emissions from internal combustion (IC) engines is a crucial goal, encompassing nitrogen oxide (NO), hydrocarbon (HC), carbon monoxide (CO), and smoke. To enhance both performance and emissions, contemporary IC engines have turned to alternative gases such as hydrogen (H2) and exhaust after-treatment systems. A promising method to effectively decrease exhaust emissions entails the application of the scrubber technique as an exhaust gas after-treatment. This study's objective is to explore two avenues for curtailing exhaust emissions. The first involves substituting traditional fuels in IC engines with hydrogen gas (H2) at a flow rate of 6 LPM. The second entails integrating a liquid chemical solution into the scrubber technique. Notably, the utilization of KMnO4 solutions exhibits an appreciable reduction in NO and CO emissions compared to solutions containing NaOH. The experimental process included two aspects: investigating hydrogen fuel (H2) as an alternative fuel for IC engines and incorporating a scrubber technique using both KMnO4 and NaOH solutions. These experiments were conducted using a single-cylinder engine with a power output of 5.2 kW, cooled by water. The engine underwent tests under various load conditions, spanning from minimal to maximal loads. The findings revealed that employing KMnO4 solutions within the scrubber technique led to reductions of 25% and 40% in NO and CO emissions, respectively, in contrast to the utilization of NaOH solutions. Similarly, introduction hydrogen gas also has a significant effect on emission reduction.

Innovative engine test bench set-up for testing of exhaust gas aftertreatment and detailed gas species analysis for CNG-SI-operation

For an efficient reduction of methane slip, a precise understanding of exhaust gas after treatment under real conditions is essential. Since it is not possible to produce catalytic converters in near-series geometry on a laboratory scale, it is necessary to resort to significantly smaller sample catalysts. Therefore, an engine test bench was designed to ensure real operating conditions for such samples with the help of space velocity and temperature control. A comparison between the actual and reference values of the space velocity results in a small deviation of 0.1% on average. Furthermore, the pressure conditions at the catalyst have been measured showing a propagation of pressure oscillations from the engine outlet which in combination with the space velocity regulation show that real conditions could be applied to the catalyst sample. Subsequently, the exhaust gas concentrations were monitored with a Fourier transform infrared spectrometer. The catalyst material used is PdO on Al2O3, common for methane oxidation. The measurements show that the CH4 conversion is higher under lean conditions, but is below complete conversion. In a final comparison between purely stoichiometric operation and dithering, the course of the CH4 conversion rate over the test period is examined more closely. In addition to sampling pre- and post-catalyst, the exhaust gas composition is measured spatially resolved within a catalyst channel using special measurement technology. In the temporal course of the CH4 emissions, a stabilizing effect due to the change of the operating mode can be seen, showing that dithering seems to prevent further deactivation.

Active regeneration particulate filter operating cycle theoretical justification

Introduction (problem statement and relevance). Particulate filters or traps used in diesel vehicles to catch suspended particles require continuous and/or periodic regeneration in order to maintain operability. The order of diesel particulate filter loading and its regeneration can be presented in the form of an algorithm. Specific features of particulate filter functioning both in regular conditions and during active regeneration have been studied in a number of scientific papers, and the results obtained in them can be considered when developing the algorithm.The purpose of the work is development of the algorithm of the operating cycle of the diesel vehicle particulate filter including modes of filter loading, active regeneration and troubleshooting.Methodology and methods. Information from scientific literature regarding specific features of diesel vehicle exhaust gas aftertreatment systems operation, namely regarding particulate filters, has been collected under this study. The study assumes a noncatalytic diesel particulate filter that is contained in the system together with a diesel oxidation catalyst, nitrogen oxide reduction catalyst and ammonia oxidation catalyst. Particulate matter sensors, temperature sensors, pressure sensors, exhaust-gas flow sensors and flow sensors for fuel to burn the soot accumulated in the filter have been used as measuring instrumentation of system indicators.Results. The created algorithm of the particulate filter operating cycle included the loading mode with definition of parameters for switching to active regeneration, definition of the transition moment between the stages of deep filtration and filtration in the soot layer. Active regeneration consisted of a sequence of two controlled fuel injections for combustion of soot in the filter and occurrence of the temperature impulse between the injections with selection of the most suitable level of exhaust gas flow rate as well as the control over the filter temperature and content of oxygen. The problems of malfunctions of the treatment system were solved by controlling the fuel supply during regeneration.Scientific novelty. The peculiarities of processes in the particulate filter during active regeneration were considered in the algorithm development, including ensuring high efficiency of soot removal from the filter.Practical significance. The algorithm can be used to develop a procedure to perform bench and driving tests of diesel vehicles as well as it can be applied in a diesel engine during vehicles operation

Applications of Electric Heating Technology in Vehicle Exhaust Pollution Control

Motor vehicle exhaust is an important cause of atmospheric pollution. Nowadays, mainstream exhaust emission aftertreatment technologies, such as TWC, DOC, SCR, and DPF, usually require sufficient temperature to perform good purification or maintain normal working conditions. Compared with exhaust gas heating technologies such as engine enrichment and fuel injection, electric heating technology can quickly increase the temperature of exhaust gas aftertreatment devices without adverse effects on engine operating conditions. This article introduces the research and progress of electric heating technology combined with traditional aftertreatment devices on major types of vehicles, such as gasoline vehicles, diesel vehicles, motorcycles, and hybrid vehicles, to improve exhaust purification efficiency and its accompanying fuel consumption impact. In addition, the common structure and characteristics of electric heaters, as well as the current status and development trend of electric heating unit technologies such as electric heating power supply are introduced.

Emissions from Light-Duty Vehicles—From Statistics to Emission Regulations and Vehicle Testing in the European Union

The article offers a comprehensive examination of vehicle emissions, with a specific focus on the European Union’s automotive industry. Its main goal is to provide an in-depth analysis of the factors influencing the emission of microcontaminants from light-duty vehicles and the challenges associated with their removal via exhaust aftertreatment systems. It presents statistical insights into the automotive sector and explores the relationships between vehicle categories, fuel types, and the emission of regulated and nonregulated pollutants, as well as relevant legal regulations such as the European Emission Standard. The article delves into the characteristics of vehicle exhaust, compares exhaust-gas aftertreatment systems, and introduces factors affecting emissions from gasoline engines, including downsizing, fuel composition, and engine operating parameters. It also considers the impact of driving style, start–stop systems, and related factors. Concluding, the article offers an overview of vehicle-testing procedures, including emission tests on dynamometer chassis and real driving emissions. With the growing global vehicle population and international environmental regulations, a focus on solid particles containing microcontaminants is paramount, as they pose significant risks to health and the environment. In summary, this article provides valuable insights into vehicle emissions, significantly contributing to our understanding of this crucial environmental issue.

Exhaust gas aftertreatment to minimize NOX emissions from hydrogen-fueled internal combustion engines

Hydrogen-fueled internal combustion engines are a promising CO2-free and zero-impact emission alternative to battery or fuel cell electric powertrains. Advantages include long service life, robustness against fuel impurities and a strong infrastructural base with existing production lines and workshop stations. In order to make hydrogen engines harmless in terms of pollutant emissions as well, NOX emissions at the tailpipe must be reduced as low as the zero-impact emission level. Here, the application of selective catalytic reduction (SCR) catalysts is a promising solution that can be rapidly adopted from conventional diesel engines.This paper therefore investigates the influences of the hydrogen concentration in the raw exhaust gas, of the NO2/NOX ratio and of the space velocity on the performance of two different SCR technologies. The results show that both types of SCR, copper-zeolite and vanadium-based, have their advantages and drawbacks. Copper-based SCR catalysts have an early light-off temperature and reach maximum efficiencies of up to >99%. On the other hand, vanadium systems promise almost no secondary N2O emissions. As a result, we combined both approaches to create a superior solution with high efficiency and lowest secondary emissions.

A feasibility Study on the exhaust-gas treatment efficiency of a wet-scrubber system equipped in a diesel engine: A focus on smoke emission

A feasibility examination was conducted on a wet-scrubber system designed in this study to investigate the exhaust gas treatment efficiency of a wet-scrubber system equipped with a diesel engine. This preliminary investigation limits to evaluate the feasibility of the wet scrubber system in decreasing smoke. The influence of multiphase flow configuration in wet-scrubbing aftertreatment systems on emission formation is an interesting topic in the field of exhaust gas aftertreatment. It is our initial attempt to investigate the influence of multiphase flow configuration in a wet-scrubbing hybrid aftertreatment system on key pollutants emitted from Diesel engines in the future. This wet scrubber works by spraying water into the exhaust gas stream. The engine was tested at three-speed conditions (1,500 rpm, 1,800 rpm, and 2,000 rpm, respectively) while varying its torque from 15 to 30 N.m. The results show that under these operating conditions, the smoke level after the scrubber decreases by up to 50%. Please note that only fresh water was used in this study, and the impact of catalysts that could further decrease exhaust gas pollution will be investigated in future studies. The water droplets serve as a medium for capturing and collecting the soot particles present in the exhaust gas. Through collisions, the water droplets cause the soot particles to adhere to their surfaces, a process known as impaction. Additionally, the larger water droplets can facilitate coagulation or agglomeration of the particles, resulting in their enlargement and enhanced capture efficiency.

Super-strong adhesion of Fe-ZSM5 catalyst on metal substrate using ceramic powder spray coating for selective catalytic reduction of NOx with NH3

Fe-ZSM5 catalyst coating on stainless steel foil sheets for NOx removal NH3-SCR reaction was prepared using special ceramic powder spray coating (PSC) and conventional wash-coating methods. Super-strong catalyst adhesion on the substrates was obtained using PSC without any binder addition. The conventional slurry coating samples showed much lower adhesion strength than the PSC samples for all catalyst coating layer thicknesses. Honeycomb-shaped monolith catalyst prepared using PSC showed high NOx removal performance comparable to the wash-coated catalyst for both standard and fast NH3-SCR reactions. The PSC catalysts having strong adhesion to metal substrates with good catalytic performance can be a promising candidate for exhaust gas after-treatment exposed to harsh mechanical conditions such as pre-turbocharger applications under very high flow rates of exhaust gas and engine vibration. The excellent catalyst adhesion property can highly enhance long-term mechanical stability of monolith catalysts.

Characterization and formulation of an environment-friendly lubricant from Pongamia (Millettia Pinnata) oil using biodegradable additives

Global efforts are being undertaken to increase the automobile industry's energy efficiency, reliability, and environmental friendliness. There are techniques to lessen the environmental issues caused by machines, such as using lightweight materials, exhaust gas after-treatment, less toxic fuel, and controlled combustion. To decrease friction and wear, especially in engines and drive trains, proper lubrication is necessary at the required operating conditions for an automobile's safe and dependable operation. Mineral, synthetic, and semi-synthetic oils have been employed as lubricants; however, their disposal damages the ecosystems. Concerns about environmental deterioration are also raised by the emissions of metal traces such as calcium, magnesium, iron particles, and zinc due to burning these lubricants. Due to the limited supply of petroleum crude oil, these lubricants' present and future prospects are dismal. There is a worldwide quest for an alternative lubricant due to the environment being harmed by use of petroleum-based lubricants.The different characterization of the lubricant properties for the neat Pongamia base oil (PO) includes assessments of chemical, oxidative, rheological, thermal, and tribological properties. The fatty acid profile of PO has to be estimated using Gas chromatography–mass spectrometry. The Oxidative stability of PO should be estimated using the Differential scanning calorimetry (DSC) test. The rheological characterization should be done by evaluating kinematic viscosity, viscosity index, and dynamic viscosity. Tribological properties are studied using a four-ball tester tribometer. The lacking properties of neat PO is identified and improved using suitable additives such as antioxidants, viscosity improver, pour point depressants, anti-wear additives, etc. The biodegradability test of the formulated oil is done using bacterial turbidity assay and toxicity is checked of the final formulated oil. An IC engine test is done to check the performance of the engine and wear using formulated lubricant from PO.

In Situ Tracking of Break-up, Resuspension, and Transport of Reactive Particle Structures in a Single Wall-Flow Filter Channel

Particulate filters are used as a standard component in the exhaust gas aftertreatment of vehicles. The reactive (soot) and inert (ash) particles generated during engine operation are deposited in wall-flow filter. The resulting particle layer increases the differential pressure of the filter, which is why it is regenerated regularly. During regeneration of the filter, the reactive particles oxidize, and the inert particles remain in the filter. The oxidation of the soot particles results in a layer break-up, and the resuspension of particle structures can occur. The layer break-up over the entire length of an inlet channel and the resuspension of particle structures have not yet been observed, which is why the fundamental processes in a particulate filter have not yet been fully clarified. In these investigations, the regeneration of a single wall-flow filter channel is observed in situ with high temporal and spatial resolution. For this purpose, the filter is loaded with soot particles and regenerated subsequently. The regeneration of the filter is analyzed in relation to the process parameters of temperature, layer thickness, and flow velocity. Before the visual layer break-up, the pressure drop decreases and declines to a constant value before resuspension of particle structures are detected. As the temperature is increased, the regeneration time is reduced. With a thicker particle layer, the particle structures formed during layer break-up become larger, the location of resuspension shifts to the posterior channel region, and the number of resuspensions increases. A higher flow velocity causes more particle structures to be resuspended and transported to the channel end.

Role of oxidation catalysis in after-treatment of exhaust gases of diesel engines

Introduction (problem statement and relevance). The oxidation catalysis provides the necessary efficiency and performance of diesel filters for trapping dispersed particles and systems for selective treatment of nitrogen oxides. In addition, oxidation catalysts can be a tool for neutralizing emissions of methane and some non-regulated but very hazardous polycyclic and partially oxidized hydrocarbons. There are also poorly studied theoretical issues of oxidation catalysis associated with mutual influence of toxic components contained in exhaust gases of diesel engines.The purpose of the study is to clarify the oxidation catalysis role in the general problem of after-treatment of toxic emissions of diesel engines, development and testing of catalysts and converters for neutralization of toxic combustion products of engines powered by natural gas.Methodology and research methods. Research into the catalysts under flow conditions using modern methods of gas analysis, IR spectroscopy, engine tests of the developed catalytic converters.Scientific novelty and results. The paper shows the role of oxidation catalysis in solving the common problems of after-treatment of hazardous emissions of diesel engines including both direct after-treatment of toxic compounds and supporting functions. Catalysts of higher efficiency and a series of converters for gas engines have been developed. Innovative methods to increase the resistance of oxidation catalysts to sulfur oxides have been proposed.Practical significance. The developed catalysts and converter designs are recommended for implementation in KAMAZ-820.52-260 and Cummins 250 and 280 gas engines.

Two-dimensional calculation model for hazardous substances formation in combustion products of a spark-ignition engine

Introduction (problem statement and relevance). Improvement of environmental parameters of internal combustion engines is one of the most relevant tasks of the domestic transport engineering. Calculation support allows reducing the time and raising the efficiency of works for refining of the bench work process in order to meet the required parameters. The paper is devoted to development of a two-dimensional calculation model for hazardous substances formation in combustion products of spark-ignition engines based on the non-equilibrium kinetic models of formation of nitrogen oxides and carbon monoxide.Methodology and research methods. Computational methods for differential equations (ordinary and partial ones) are applied. Non-equilibrium kinetics of hazardous substances formation in combustion products is considered. The work process is calculated based on a combination of the mesh control-volume method and determination of the observable flame rate based on the experimental data (taking into account the development stage of the flame source).Scientific novelty and results. The new calculation method for flame propagation in the spark-ignition engine is suggested. The developed model combines such advantages as good predictability and short time of calculation.Practical significance. The model can be applied, in particular, to preliminary planning of three-dimensional calculations of the work process or their check in the absence of experimental data (at the stage of preliminary/concept design). The calculation results can be used as initial data for modeling of the exhaust gas aftertreatment (additional purification) system.

Results of recurrent in-service exhaust gas measurements with an EU stage IV forest harvester fuelled with rapeseed oil within the emission durability period

The real driving emissions of an EU stage IV forest harvester were measured four times within five years to monitor long-time emission behaviour. In this period, the harvester worked 7650 h in total, thereof 6300 h with pure rapeseed oil fuel DIN 51605 (R100) and 1350 h with conventional diesel fuel initially. Data analysis according to relevant EU regulation 2017/655 shows that the emission behaviour complies with the legal requirements of exhaust gas stage IV within the five years under consideration. According to EU regulation 2016/1628 the achieved 7650 operating hours nearly correspond to the emission durability period of 8000 h. However, between the single measurements some differences in emission results are clear evident. They are primarily caused by different working profiles, and unavoidable random events. Detailed analysis of the results showed that the measured nitrogen oxides (NOX), carbon monoxide, and hydrocarbons remain at the same level over time at comparable operation conditions. Thus, the operation time had no major impact on the emission behaviour of the harvester. During cold start and non-working events higher nitrogen oxides (NOX) concentrations are observed in the exhaust since the exhaust aftertreatment system is not within its operation temperature. When the exhaust gas aftertreatment is within its operating range, exhaust emissions are at a very low level indicating an efficient, clean combustion. It can be concluded that the operation of the harvester with R100 did not affect the emission behaviour and functionality of the exhaust gas aftertreatment system.

Parametric evaluation of ducted fuel injection in an optically accessible mixing-controlled compression-ignition engine with two- and four-duct assemblies

Ducted fuel injection (DFI) is a strategy to improve fuel/charge-gas mixing in direct-injection compression-ignition engines. DFI involves injecting fuel along the axis of a small tube in the combustion chamber, which promotes the formation of locally leaner mixtures in the autoignition zone relative to conventional diesel combustion. Previous work has demonstrated that DFI is effective at curtailing engine-out soot emissions across a wide range of operating conditions. This study extends previous investigations, presenting engine-out emissions and efficiency trends between ducted two-orifice and ducted four-orifice injector tip configurations. For each configuration, parameters investigated include injection pressure, injection duration, intake manifold pressure, intake manifold temperature, start of combustion timing, and intake-oxygen mole fraction. For both configurations and across all parameters, DFI reduced engine-out soot emissions compared to conventional diesel combustion, with little effect on other emissions and engine efficiency. Emissions trends for both configurations were qualitatively the same across the parameters investigated. The four-duct configuration had higher thermal efficiency and indicated-specific engine-out nitrogen oxide emissions but lower indicated-specific engine-out hydrocarbon and carbon monoxide emissions than the two-duct assembly. Both configurations achieved indicated-specific engine-out emissions for both soot and nitrogen oxides that comply with current on- and off-road heavy-duty regulations in the United States without exhaust-gas aftertreatment at an intake-oxygen mole fraction of 12%. High-speed in-cylinder imaging of natural soot luminosity shows that some conditions include a second soot-production phase late in the cycle. The probability of these late-cycle events is sensitive to both the number of ducted sprays and the operating conditions.

The Impact of Ammonia Fuel on Marine Engine Lubrication: An Artificial Lubricant Ageing Approach

Ammonia is a prospective zero-carbon-emission fuel for use in large marine diesel engines. Current research focuses on several technical aspects, such as injection strategies or exhaust gas aftertreatment options, but investigations regarding the impact of ammonia on engine oil degradation are largely absent from the literature. This study provides a methodology with which to evaluate this phenomenon via artificial oil alteration. By using an admixture of various contaminations to air, such as ammonia and its partial combustion product nitrogen dioxide, their respective impacts on chemical oil degradation were assessed. Subsequently, the lubricating performance of altered oils was investigated, with a focus on corrosion properties, deposit formation, and load-bearing capability. Although the application of a stoichiometric ammonia–air mixture resulted in less pronounced thermo-oxidative degradation compared to alteration with neat air, static and dynamic deposit formation as well as corrosion properties and load-bearing capability were severely impacted by the presence of ammonia. On the contrary, nitrogen dioxide contamination resulted in higher oxidation and acidification of the oil, but altered samples performed considerably better than ammonia-altered aliquots in terms of coking tendencies, corrosivity, and load bearing.

Achieving Zero-Impact Emissions with a Gasoline Passenger Car

The Euro 7 legislation and the Zero-Impact Emissions concept aim at significantly improving air quality. Technologies that reduce pollutant emissions beyond current gasoline passenger cars have already been intensively investigated, but a holistic system layout considering extended boundary conditions is missing so far. This paper therefore develops technical solutions to achieve a Euro 7 scenario and Zero-Impact Emissions for a 2030+ vehicle. First, challenging test scenarios are identified to develop compliant vehicles. The scenarios cover extreme conditions in real-world driving, such as hot and cold ambient conditions, stop-and-go in rural areas or high speed and steep gradients on highways. Different technology options are discussed and selected for the investigations. An empirical–physical simulation model for the exhaust gas aftertreatment system is extended with new technologies, such as an electrical heater disc in front of the catalyst or a burner in the exhaust system. In addition to stoichiometric engine operation and increased catalyst volume, the results show that the expected Euro 7 regulations can be achieved in all extreme scenarios by combining additional exhaust gas heating with engine power limitation or pre-heating. Moreover, even Zero-Impact Emissions are achieved in most cases with the same technology options.