Deactivation of a Vanadium-Based SCR Catalyst Used in a Biogas-Powered Euro VI Heavy-Duty Engine Installation

We have investigated how the exhaust gases from a heavy-duty Euro VI engine, powered with biogas impact a vanadium-based selective catalytic reduction (SCR) catalyst in terms of performance. A full Euro VI emission control system was used and the accumulation of catalyst poisons from the combustion was investigated for the up-stream particulate filter as well as the SCR catalyst. The NO(x)reduction performance in terms of standard, fast and NO2-rich SCR was evaluated before and after exposure to exhaust from a biogas-powered engine for 900 h. The SCR catalyst retains a significant part of its activity towards NO(x)reduction after exposure to biogas exhaust, likely due to capture of catalyst poisons on the up-stream components where the deactivation of the oxidation catalyst is especially profound. At lower temperatures some deactivation of the first part of the SCR catalyst was observed which could be explained by a considerably higher surface V4+/V(5+)ratio for this sample compared to the other samples. The higher value indicates that the reoxidation of V(4+)to V(5+)is partially hindered, blocking the redox cycle for parts of the active sites

Control of Hybrid Electric Vehicles with Diesel Engines

This thesis is an approach to improve electric hybrid vehicles with respect to fuel consumption and to fulfil the future intended NOX emission regulations. It is based upon the conclusions made in the licentiate thesis Analysing Hybrid Drive System Topologies (Jonasson, 2002). The study in this thesis is restricted to a parallel hybrid vehicle equipped with a diesel engine, two electric machines and electrical energy storage and a model thereof is presented in the thesis. The choice to focus on the diesel engine is related to the high efficiency of this engine that also is the reason for the in later years increased market for diesel engines in conventional vehicles. Since one of the disadvantages, related to the diesel engine, are the nitrogen oxides (NOX) emissions, efforts is concentrated on reducing them, by means of the advantages of hybridisation. The reference vehicle in the simulations presented in this thesis is a Toyota Prius, an electric hybrid passenger car, which is available on the market today. As input for the combustion engine model, engine data from a diesel engine considered as state of the art 2004, has been used. The engine data is scaled to correspond to the engine size used in the Prius. It should be mentioned that the engine in the Toyota Prius is run on petrol. There are many possible parameters in the simulation model, which are adjustable; vehicle chassis parameters, engine, electric machine(s) and battery size and types, losses models, charging strategies and driver behaviour etc. A number of key parameters have been selected in this study: control strategy, NOX control by means of EGR (exhaust gas recirculation) and SCR (selective catalytic reduction), gear ratios and gearshift strategies and finally cylinder deactivation. The accuracy of the simulation model is ratified by means of measured data on the engine used in the simulation. Fuel consumption and NOX are determined by using look-up-tables based on measured data. The engine temperature, needed to determine the NOX conversion by means of SCR, is also received from a look-up-table. The simulation model is evaluated in the driving cycle ECE+EUDC. The results presented are chosen to illustrate the impact each individual parameter has on the behaviour of the hybrid vehicle, the fuel consumption and the emissions. The results from the simulations show that it is possible to pass the expected limit of the future Euro 5 NOX regulations, if NOX emission treatment with EGR and SCR is implemented. The price to pay for this action is to sacrifice some of the fuel savings that the hybridization brings. The result is nevertheless a vehicle with decreased fuel consumption compared with a conventional diesel powered vehicle, and a vehicle that passes the intended emission regulation

Ammonia Emission Assessment from Gasoline and Diesel Engines under Utah Specific Conditions

This study aims to quantify ammonia (NH3) emission rates from the on-road gasoline and diesel motor vehicles fleet of the Wasatch Front, Utah. For this purpose, a portable Pollution Emissions Monitoring System (PEMS) was used to estimate NH3 emission rates from a representative fleet of 53 in-use light-duty (LD) gasoline and diesel vehicles over a total of 166 on-road Real Driving Emissions (RDE) tests. The post-catalyst concentrations of NH3 precursors, nitrogen oxides (NOx) and carbon monoxide (CO) were also measured. The outcomes of this study showed that a motor vehicle in the Wasatch Front would emit 55.6 mg for every traveled mile. The average NH3 emission rates of gasoline and diesel motor vehicles were 62 and 10.7 mg/mile, respectively. Together, the on-road gasoline and diesel motor vehicles in the Wasatch Front produce an estimated 1,496.5 metric tons of NH3 every year. The study also showed that vehicle characteristics (model year, mileage reading, engine displacement and number of cylinders), the concentration of NH3 precursors (carbon monoxide and oxides of nitrogen) and driving conditions impact NH3 emission rates from the on-road vehicles fleet. Thus, limiting the number of old on-road vehicles with aged catalytic converters by replacing them with newer vehicles or repairing their exhaust control devices would significantly reduce NH3 emission rates from motor vehicles fleet

Diesel and Gasoline Engines

The internal combustion engine was invented around 1790 by various scientists and engineers worldwide. Since then the engines have gone through many modifications and improvements. Today, different applications of engines form a significant technological importance in our everyday lives, leading to the evolution of our modern civilization. The invention of diesel and gasoline engines has definitely changed our lifestyles as well as shaped our priorities. The current engines serve innumerable applications in various types of transportation, in harsh environments, in construction, in diverse industries, and also as back-up power supply systems for hospitals, security departments, and other institutions. However, heavy duty or light duty engines have certain major disadvantages, which are well known to everyone. With the increasing usage of diesel and gasoline engines, and the constantly rising number of vehicles worldwide, the main concern nowadays is engine exhaust emissions. This book looks at basic phenomena related to diesel and gasoline engines, combustion, alternative fuels, exhaust emissions, and mitigations

A New Generation of Hydrogen-Fueled Hybrid Propulsion Systems for the Urban Mobility of the Future

The H2-ICE project aims at developing, through numerical simulation, a new generation of hybrid powertrains featuring a hydrogen-fueled Internal Combustion Engine (ICE) suitable for 12 m urban buses in order to provide a reliable and cost-effective solution for the abatement of both CO2 and criteria pollutant emissions. The full exploitation of the potential of such a traction system requires a substantial enhancement of the state of the art since several issues have to be addressed. In particular, the choice of a more suitable fuel injection system and the control of the combustion process are extremely challenging. Firstly, a high-fidelity 3D-CFD model will be exploited to analyze the in-cylinder H2 fuel injection through supersonic flows. Then, after the optimization of the injection and combustion process, a 1D model of the whole engine system will be built and calibrated, allowing the identification of a “sweet spot” in the ultra-lean combustion region, characterized by extremely low NOx emissions and, at the same time, high combustion efficiencies. Moreover, to further enhance the engine efficiency well above 40%, different Waste Heat Recovery (WHR) systems will be carefully scrutinized, including both Organic Rankine Cycle (ORC)-based recovery units as well as electric turbo-compounding. A Selective Catalytic Reduction (SCR) aftertreatment system will be developed to further reduce NOx emissions to near-zero levels. Finally, a dedicated torque-based control strategy for the ICE coupled with the Energy Management Systems (EMSs) of the hybrid powertrain, both optimized by exploiting Vehicle-To-Everything (V2X) connection, allows targeting H2 consumption of 0.1 kg/km. Technologies developed in the H2-ICE project will enhance the know-how necessary to design and build engines and aftertreatment systems for the efficient exploitation of H2 as a fuel, as well as for their integration into hybrid powertrains

Energy and Emissions Conscious Optimal Following for Automated Vehicles with Diesel Powertrains

The emerging application of autonomous driving provides the benefit of eliminating the driver from the control loop, which offers opportunities for safety, energy saving and green house gas emissions reduction by adjusting the speed trajectory. The technological advances in sensing and computing make it realistic for the vehicle to obtain a preview information of its surrounding environment, and optimize its speed trajectory accordingly using predictive planning methods. Conventional speed following algorithms usually adopt an energy-centric perspective and improve fuel economy by means of reducing the power loss due to braking and operating the engine at its high fuel efficiency region. This could be a problem for diesel-powered vehicles, which rely on catalytic aftertreatment system to reduce overall emissions, as reduction efficiency drops significantly with a cold catalyst that would result from a smoother speed profile. In this work, control and constrained optimization techniques are deployed to understand the potential for and achieve concurrent reduction of fuel consumption and emissions. Trade-offs between fuel consumption and emissions are shown using results from a single objective optimal planning problem when the calculation is performed offline assuming full knowledge of the whole cycle. Results indicate a low aftertreatment temperature when energy-centric objectives are used, and this motivates the inclusion of temperature performance metric inside the optimization problem. An online optimal speed planner is then designed for concurrent treatment of energy and emissions, with a limited but accurate preview information. An objective function comprising an energy conscious term and an emissions conscious term is proposed based on its effectiveness of 1) concurrent reduction of fuel and emissions, 2) flexible balancing between the emphasis on fuel saving or emissions reduction based on performance requirements and 3) low computational complexity and ease of numerical treatment. Simulation results of the online optimal speed planner over multiple drive cycles are presented, and for the vehicle simulated in this work, concurrent reduction of fuel and emissions is demonstrated using a specific powertrain, when allowing flexible modification of the drive cycle. Hardware-in-the-loop experiment is also performed over the Federal Test Procedure (FTP) drive cycle, and shows up to 15% reduction in fuel consumption and 70% reduction in NOx emissions when allowing a flexible following distance. Finally, the stringent requirement of accurate preview information is relaxed by designing a robust re-formulation of the energy and emissions conscious speed planner. Improved fuel economy and emissions are shown while satisfying the constraints even in the presence of perturbations in the preview information. A Gaussian mixture regression-based speed prediction is applied to test the performance of the speed following strategy without assuming knowledge of the preview information. A performance degradation is observed in simulation results when using the predicted velocity compared with an accurate preview, but the speed planner preserves the capability to improve fuel and tailpipe emissions performance compared with a non-optimal controller.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/170004/1/huangchu_1.pd

Diesel and Gasoline Engines

The internal combustion engine was invented around 1790 by various scientists and engineers worldwide. Since then the engines have gone through many modifications and improvements. Today, different applications of engines form a significant technological importance in our everyday lives, leading to the evolution of our modern civilization. The invention of diesel and gasoline engines has definitely changed our lifestyles as well as shaped our priorities. The current engines serve innumerable applications in various types of transportation, in harsh environments, in construction, in diverse industries, and also as back-up power supply systems for hospitals, security departments, and other institutions. However, heavy duty or light duty engines have certain major disadvantages, which are well known to everyone. With the increasing usage of diesel and gasoline engines, and the constantly rising number of vehicles worldwide, the main concern nowadays is engine exhaust emissions. This book looks at basic phenomena related to diesel and gasoline engines, combustion, alternative fuels, exhaust emissions, and mitigations

An evaluation of renewable fuels´ potential to reduce global and local emissions in non-road and heavy-duty on-road sectors

Achieving carbon neutrality in the European Union by 2050 requires deep reductions in greenhouse gas emissions in all forms of transport. Powertrain electrification and hybridisation are growing trends for light vehicles. Instead, electrification of maritime and heavy long-distance transport is far more difficult due to their massive energy needs. Battery technology is also problematic for mobile non-road machinery operating for long periods far from the charging infrastructure. However, fuel choices can significantly influence greenhouse gas emissions from internal combustion engines. Therefore, a transition to alternative fuels is one of the strategies under discussion. This study investigated the emission performance of two alternative fuels: biomethane and tall oil-based renewable diesel. In addition to greenhouse gas emissions, the harmful local emissions originating from fuel combustion were investigated. Biomethane was evaluated through a case study of a RoPax vessel operating in the Baltic Sea. In addition, real-driving emissions from a biomethane-powered city bus were measured. The study of renewable diesel´s emissions was carried out with engine experiments on an off-road diesel engine under laboratory conditions. Greenhouse gas emissions were calculated over the entire life cycle of the fuels. The results showed that using renewable fuels derived from sustainable biomass sources can reduce life-cycle greenhouse gas emissions by 65−90 % compared with fossil fuels. In addition, biomethane and renewable diesel can immediately improve local air quality by reducing local emissions. Burning liquefied biomethane reduced particulate matter by 80 % relative to marine diesel oil. Sulphur dioxide emissions were negligible and NOx emissions were low. Renewable diesel slightly reduced all regulated local gaseous emissions. The reduction in particulate number was more significant, at up to 26 % compared with conventional market diesel. Biomethane and renewable diesel proved to be effective ways to decarbonise transport in the short to medium term in hard-to-abate sectors with no immediate alternatives. The primary concern with biomethane and renewable diesel today is their limited availability. Guaranteed long-term policy is needed to scale up the supply of sustainably produced biofuels and accelerate the necessary investments.Hiilineutraaliuuden saavuttaminen EU:ssa vuoteen 2050 mennessä vaatii kasvihuonekaasujen merkittävää vähentämistä koko liikennesektorilta. Sähköistys ja hybridisaatio ovat kasvavia trendejä kevyissä ajoneuvoissa. Sen sijaan raskaan runkoliikenteen ja laivaliikenteen vaatimat suuret energiamäärät on vaikea korvata sähköllä. Liikkuvien työkoneiden kohdalla sähköistystä vaikeuttaa puuttuva latausinfrastruktuuri. Polttomoottoreiden kasvihuonekaasupäästöihin voidaan kuitenkin merkittävästi vaikuttaa polttoainevalinnoilla. Tämän vuoksi siirtyminen vaihtoehtoisiin polttoaineisiin on yksi keskustelun kohteena olevista strategioista. Tässä tutkimuksessa selvitettiin biometaanin ja mäntyöljypohjaisen uusiutuvan dieselpolttoaineen käytön vaikutuksia päästöihin. Kasvihuonekaasupäästöjen lisäksi selvitettiin polttoaineiden poltosta aiheutuvat haitalliset paikallispäästöt. Biometaania tutkittiin Itämerellä liikennöivään matkustaja-autolauttaan kohdistuvalla tapaustutkimuksella. Lisäksi tutkittiin biometaanikäyttöisen kaupunkibussin ajonaikaisia päästöjä todellisissa ajo-olosuhteissa. Uusiutuvalla dieselillä päästömittaukset tehtiin työkonedieselmoottorikokeilla laboratorio-olosuhteissa. Kasvihuonekaasupäästöt laskettiin polttoaineiden koko elinkaaren ajalta. Tulokset osoittivat, että kestävistä biomassalähteistä tuotettujen uusiutuvien polttoaineiden käyttö voi vähentää elinkaaren aikaisia kasvihuonekaasupäästöjä 65–90 % fossiilisiin polttoaineisiin verrattuna. Lisäksi biometaanilla ja uusiutuvalla dieselillä voidaan välittömästi parantaa paikallista ilmanlaatua, koska polton aikaiset paikallispäästöt vähenevät. Nesteytetty biometaani pienensi meriliikenteen hiukkaspäästöjä 80 % dieselöljykäyttöön verrattuna. Rikkidioksidipäästöt vähenivät 99 % dieselöljyyn verrattuna ja typen oksidit olivat alhaiset. Uusiutuvalla dieselillä kaikki säännellyt kaasumaiset paikallispäästöt olivat hieman pienempiä kuin dieselöljyllä. Uusiutuvalla dieselillä hiukkaslukumäärä laski jopa 26 % perinteiseen fossiiliseen dieseliin verrattuna. Biometaani ja uusiutuva diesel osoittautuivat tehokkaiksi keinoiksi vähentää liikenteen kasvihuonekaasupäästöjä lyhyellä ja keskipitkällä aikavälillä vaikeasti sähköistettävässä liikenteessä. Biometaanin ja uusiutuvan dieselin ensisijainen huolenaihe on niiden rajallinen saatavuus. Kestävästi tuotettujen polttoaineiden tarjonnan lisäämiseksi ja välttämättömien investointien nopeuttamiseksi tarvitaan päättäväistä pitkän aikavälin politiikkaa.fi=vertaisarvioitu|en=peerReviewed

Unraveling the fingerprints of NOx using stable isotopes: Implications for NOx source partitioning and oxidation chemistry

The nitrogen (N) and oxygen (O) stable isotope composition (δ15N & δ18O) of nitrogen oxides (NOx )may be a useful tool for constraining NOx emission sources as well as for understanding the atmospheric oxidation pathways responsible for its removal if various NOx sources and sink processes exhibit characteristic isotopic compositions (“fingerprints”). However, this requires (1) an accurate and complete inventory of δ15N(NOx) values from major emission sources, (2) an assessment of the kinetic and equilibrium isotope effects that can impact δ15N and δ18O values of NOx, (3) and test these assumptions by conducting accurate in situ δ15N and δ18O measurements of atmospheric NOx. To this end, I have characterized the δ15N(NOx) signatures from various fossil-fuel NOx sources, including buses, trucks, lawn equipment, natural gasfired boilers, and airplanes. These δ15N(NOx) source characterization studies along with prior studies indicate that soil emission (nitrification/denitrification), “thermal” NOx producedfromfossil-fuelcombustion, and“source” NOx producedfromcoal-fired power plants have relative distinctive values. In addition, both my experimental and theoretical investigations on the isotope effects associated with NOx oxidation indicate that isotopes effects via equilibrium isotope exchange and kinetic isotope effects occurring during NOx oxidation reactions may influence the δ15N and δ18O values of atmospheric nitrate. Using these calculated isotope effects, I developed a simple model for the production of atmospheric nitrate through its three major pathways thatinclude(1)NO2 +•OH→HNO3, (2)N2O5 +surface→2HNO3, and(3)NO3+ R→•R. This model indicated that these pathways result in distinctive δ18O-δ15N relationships that tend to match reported literature values. Finally, in order to evaluate the influences of NOx emission sources and isotope effects on the isotope composition of NO2, which serves as precursor molecule to atmospheric nitrate, ambient NO2 was collected and analyzed for 15N and 18O . These results suggest that δ18O of NO2 has a distinctive diurnal profile reflecting the photochemical cycling of NOx while δ15N of NO2 tends to track with NOx sources with small but significant isotope effects altering daytime δ15N(NO2) by approximately 2-4%. Overall, this research has refined the “fingerprints” of atmospheric NOx and will be useful for future studies aimed at understanding regional and spatial distributions in NOx emission budgets and tracing NOx oxidation chemistry