Reduction Of Particulate Emissions Research Articles

Present and future emission characteristics of air pollutants and CO2 from the Beijing transport sector and their synergistic emission reduction benefits

Coordinated control of both carbon dioxide (CO2) and air pollutants from the urban transport sector will deliver the greatest benefit to climate and health. To calculate and assess the synergistic control effect on CO2 and air pollutants from various transport types in Beijing from 2021 to 2050, we built a quantitative analysis model based on the Long-range Energy Alternatives Planning framework. Results showed that passenger transport was the dominant contributor to CO2 and major air pollutants (fine particles, carbon monoxide, volatile organic compounds) emitted from the transport sector in 2021 in Beijing. An exception is for nitric oxide which was mostly from freight transport. Clean energy alternatives for road vehicles and aviation, and electrification of railways offer the best synergistic emission reduction potential for both CO2 and air pollutants, and are also the most important measure to realize carbon neutrality in transportation. A change in transport mode (e.g. from road to rail) and the early elimination of aging vehicles would lead to a greater synergistic effect than that achieved by improving fuel economy in the short-term, except for co-benefits for fine particles and CO2 for which the fine particle emission reduction was much lower than that of CO2. In general, the adoption of clean energy for motor vehicles and aviation (e.g., electric vehicles, hydrogen fuel cell vehicles, and bio-fuels), is the best way for Beijing to quickly pass the carbon peak and achieve neutrality in the transport sector and improve air quality in the future.

Characterization of in-cylinder spatiotemporal flame and solid particle emissions for ethanol-gasoline blended in gasoline direct injection engines

Stricter regulations for internal combustion engines have necessitated the inclusion of eco-friendly fuels with conventional ones to reduce gas and solid emissions. Gasoline direct injection (GDI) engines, however, have been found to produce more particle number and mass emissions than port fuel injection engines. To address this, bioethanol fuel has been selected as an additive eco-friendly fuel for gasoline, with the aim of reducing particle emissions. In this study, we quantitatively characterize in-cylinder spatiotemporal flame to feature combustion performance and particle emissions for ethanol fuel in the GDI combustion chamber. We examined three engine combustion modes differed in equivalence ratio and injection strategy to produce various combustion results to quantify combustion performance and particle emission characteristics. Using an eight-channel non-intrusive flame luminosity sensor in one cylinder, we measured the flame front and its propagation direction. At the tailpipe, we measured particulate emissions using an engine exhaust particle sizer and a micro soot sensor coupled with a catalytic stripper that removed semi-volatile compounds. Our study found that increasing ethanol fuel content for different combustion modes resulted in distinct combustion and flame development. The particle size distribution also showed different patterns at each combustion mode, depending on the ethanol content. Lean combustion modes yielded high diffusion flame intensity compared to stoichiometric combustion mode, which resulted in a larger amount of particle formation. The physical properties of ethanol fuel were found to predominantly determine the fuel-air mixture quality, combustion process, and flame development at each combustion mode. An increase in ethanol fuel content at lean-homogeneous mode resulted in higher diffusion flame intensity and larger particle emissions. Our comparative study of flame and solid particles for ethanol fuel content improves the understanding of in-cylinder combustion processes and their correlations.

Effects of a gasoline particulate filter on the physicochemical characteristics of particulate matter from a gasoline engine

Gasoline particulate filters (GPFs) are being used increasingly in gasoline direct-injection engines because they can reduce particle emissions and allow emission regulations to be met. Therefore, understanding the particles' physicochemical properties can help with optimizing the post-processing systems and engine calibration. In this study, particles were collected both pre- and post-GPF using a Dekati® low-pressure impactor and a quartz-fiber filter membrane. High-resolution transmission electron microscopy was used to observe the morphologies of the particles, the fractal dimension was used to quantify the aggregate structure, and an image-processing program developed in MATLAB was used to analyze the nanostructures of the primary particles. Raman spectroscopy was used to study the order degree of the particles’ carbon crystal arrangement, and Fourier transform infrared spectroscopy was used to assess the changes in their surface functional-group content. After the particles were graded according to particle size, it was found that (i) the fractal dimension of all size levels and (ii) the average size of the primary particles were both smaller post-GPF than pre-GPF. Post-GPF, there was a higher proportion of nucleated particles, the particle fringe length was shorter, the tortuosity and separation were both greater, the particles were more disordered, the ratio of C–H to C–O was greater, and the proportion of organic composition of the particles and their oxidation activity were both increased.

Reducing particle emissions of heavy-duty diesel vehicles in India: Combined effects of diesel, biodiesel and lubricating oil

Diesel engines contribute significantly to deteriorating air quality. Tightening legislation has led to various technological advances, but developments differ between countries. In India, air quality has not improved and fine particle (PM2.5) related premature deaths are predicted to increase. In this study, we characterized the particle emissions of an Indian-manufactured BS IV (Bharat Stage, comparable to Euro emission standards) heavy-duty diesel vehicle and studied the effects of different fuels, fuel blends and lubricating oils. The main aims of the study were to investigate the particle emission dependency on fuel types and fuel blends used in India and to produce useful data for further use (e.g. legislative parties and modeling): emission factors (PN, PM, BC, other chemical compounds), size distributions and volatility of particles. Additionally, the sensitivity of the emissions to the lubricating oil choice was studied. Two lubricating oils, two fossil fuels conforming to BS IV and BS VI emission standards and two biofuel – BS IV fossil fuel blends were tested, one containing Renewable Paraffinic Diesel (RPD) and the other renewable Fatty Acid Methyl Ester (r-FAME). The tests were conducted on a chassis dynamometer (Delhi Bus Driving Cycle, DBDC). Our results show that the emitted particles were in ultrafine particle size range, and both the soot mode particles and smaller nanoparticles were affected by fuels and lubricating oils. The transition from BS IV grade diesel to BSVI was shown to have potential in reducing particle emissions (PN and eBC) of heavy-duty diesel vehicles in India. Blending fossil fuel with biofuel strongly affected particle number emissions, chemical composition, and eBC emissions and the emissions were highly sensitive to biofuel type. Changing the lubricating oil had a comparable magnitude of effect as changing the fuel and the results indicate that in order to reduce particle emissions, a combination of fuel and lubricating oil should be chosen, instead of choosing them separately.

Module-based simulation model for prediction of convective and condensational heat recovery in a centrifugal wet scrubber

• Heat recovering scrubber increases thermal efficiency of boiler with up to 20 %. • Module-based simulation model on heat recovery has been developed and validated. • The developed simulation model shows mean error of 5.6 % with low computation time. • Evaporative cooling further increases heat recovery as predicted by the simulation. Biomass combustion is a carbon-neutral method to generate heat and power and is integral to combating climate change. The wet scrubber is a promising device for recovering heat and reducing particle emissions from flue gas, under the driving force of new European Union legislation. Here, the heat recovery of a wet scrubber was investigated using process data and computer simulations. The process data showed that the scrubber could continuously recover heat corresponding to 10–20% of the energy input. The simulation model consists of two interlinked modules: Module 1 simulates droplet movement in the scrubber, while Module 2 uses the output of Module 1 to predict the heat recovery. The model was validated against process data, showing a mean error of 5.6%. Further optimization was based on the validated model by varying different process parameters, including nozzle position and moisture addition to the flue gas. Moisture addition was shown to be a feasible strategy for potentially increasing heat recovery by up to 3.3%. These results indicate that heat recovery in wet scrubbers is a feasible way to make particle removal cost effective in medium-scale combustion facilities, and that the developed simulation model can play an important role in optimizing these processes.

Synthesis of Methanol From a Chemical Looping Syngas for the Decarbonization of the Power Sector

Abstract One promising pathway for carbon capture and utilization is represented by the coupling of chemical looping cycles with liquid fuel synthesis processes. Methanol is an interesting fuel for gas turbines engines, due to its potential reduction of NOX and particulate emissions along with the absence of SO2 emissions. In this work, methanol production from the syngas generated by a three-reactors chemical looping process is investigated by mass and energy balances. The cycle is composed by a reducer reactor, where Fe2O3 is reduced to FeO by the injection of a reducing agent; an oxidizer reactor, where FeO reacts with CO2 and H2O to produce a syngas; an air reactor, where Fe3O4 is regenerated to Fe2O3 by ambient air. The produced syngas is then sent to a methanol synthesis plant. Several syngas compositions deriving from different CO2/(H2O+ CO2) molar fractions (1–3) at the oxidizer inlet are taken into account. The resulting methanol flow rates are almost equal in all investigated configurations (about 0.35 t/h). From an energy standpoint, the required electric power is greater for higher hydrogen mole fractions in the syngas. However, the case with 75% H2 content is characterized by the greatest methanol yield (12.6%), carbon efficiency (23%) and a high feed/recirculation ratio (0.80), thus representing the most indicated configuration among the investigated ones. Finally, by burning methanol in a gas turbine, the total CO2 emissions are halved with respect to the case without the system (if the CO2 associated with biogenic carbon in the reducer reactor is considered as net-zero).

Impact of fuel ethanol content on regulated and non-regulated emissions monitored by various analytical techniques over flex-fuel and conversion kit applications

This study evaluates the impact of ethanol content on both regulated and non-regulated emissions with recent vehicle technologies. The three vehicles used here are complying with Euro 6d-temp or Euro 6c emission standards and are adapted to variable ethanol concentrations, either through flex-fuel or E85 conversion kit. Both regulated and non-regulated emissions are characterized to highlight the fuel and vehicle technology impacts. The analysis of non-regulated pollutants in exhaust gases is performed with three different techniques to evaluate their advantages or limitations and assess time-resolved emission levels. HPLC coupled to UV detection to measure aldehydes and ketones. GC–MS was used for PAHs characterization. GC-FID was used to measure VOCs (C1 to C12) on the first phase of the WLTC. FTICR-MS was used to assess time-resolved emission levels. Results indicate a negligible impact on the emissions for ethanol content from 10 to 20% vol. Nevertheless, a significant emission composition variation is observed at 50% vol., and this is even more pronounced with 85% vol. of ethanol. Expected trends based on the literature review are confirmed for all vehicles and this includes an increase in unburned ethanol and aldehydes emissions with higher ethanol content while in this condition lower aromatics contribute to reduce particulate matters emissions. The use of varying amounts of ethanol in recent and diverse Euro 6d-temp vehicle technologies shows that the increase in ethanol content is unaffected by the reduction in particulate emissions and the increase in the finest. However, the results indicate a risk of increased NOx emissions for Euro 6d-temp IC engines, which should be confirmed on other vehicles of similar technology. This study results also indicate that most pollutants are emitted in the engine and exhaust warm-up phase. All analytical techniques exhibited similar trends.

Aerosol emissions from a marine diesel engine running on different fuels and effects of exhaust gas cleaning measures

The emissions of marine diesel engines have gained both global and regional attentions because of their impact on human health and climate change. To reduce ship emissions, the International Maritime Organization capped the fuel sulfur content of marine fuels. Consequently, either low-sulfur fuels or additional exhaust gas cleaning devices for the reduction in sulfur dioxide (SO2) emissions became mandatory. Although a wet scrubber reduces the amount of SO2 significantly, there is still a need to consider the reduction in particle emissions directly.We present data on the particle removal efficiency of a scrubber regarding particle number and mass concentration with different marine fuel types, marine gas oil, and two heavy fuel oils (HFOs). An open-loop sulfur scrubber was installed in the exhaust line of a marine diesel test engine. Fine particulate matter was comprehensively characterized in terms of its physical and chemical properties. The wet scrubber led up to a 40% reduction in particle number, whereas a reduction in particle mass emissions was not generally determined. We observed a shift in the size distribution by the scrubber to larger particle diameters when the engine was operated on conventional HFOs.The reduction in particle number concentrations and shift in particle size were caused by the coagulation of soot particles and formation/growing of sulfur-containing particles. Combining the scrubber with a wet electrostatic precipitator as an additional abatement system showed a reduction in particle number and mass emission factors by >98%.Therefore, the application of a wet scrubber for the after-treatment of marine fuel oil combustion will reduce SO2 emissions, but it does not substantially affect the number and mass concentration of respirable particulate matters. To reduce particle emission, the scrubber should be combined with additional abatement systems.

Review of morphological and chemical characteristics of particulates from compression ignition engines

Particulates from compression ignition (CI) engines have received serious attention in the last two decades. CI engines emit higher particulate matter (PM) and nitrogen oxides (NOx) than spark ignition (SI) engines. Both these species are harmful to human health and the environment. Compared to NOx emissions, PM constitutes many more chemical species in solid and liquid phases. This review paper focuses on soot morphology and chemical characterization of PM emissions from CI engines. Effects of different fuels, lubricating oil, and engine operating conditions on particulate characteristics are analyzed exhaustively. The first part of this paper focuses on the effects of particulates on living organisms, the consequences of exposure to diesel particulates, and the composition of diesel particulates. In recent decades, micro and nano-scale characteristics of PM have been exhaustively investigated to understand its structure, formation, and chemical functionalities. Typically, particulates comprise of elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), the soluble organic fraction (SOF), and trace metals. This paper summarizes most aspects of diesel particulate emissions for the benefit of active researchers in the field and underlines the importance of particulate emission reduction from the CI engines. Diesel combustion generates particles with enormous long-chain aggregates of smaller sizes and immature soot particles. Low-temperature combustion (LTC) modes and oxygenated fuels reduce the soot emissions and generate compact/clustered aggregates. Oxygenated fuels in CI engines produce more nucleation mode particles (NMPs) and high-reactivity soot aggregates. Higher trace metal concentrations were observed in diesel origin particulates than biofuel origin particulates. Biodiesel origin particulates possess higher mutagenicity and carcinogenicity because of nitro-PAHs. Transient engine operations cause higher particulates than steady-state engine operations.

Analyzing Relationships of Conductivity and Alkalinity Using Historical Datasets from Streams in Northern Alberta, Canada

Many measurements, tools, and approaches are used to identify and track the influence of human activities on the physicochemical status of streams. Commonly, chemical concentrations are utilized, but in some areas, such as downstream of coal mines, capacity indices such as specific conductivity have also been used to estimate exposure and risk. However, straightforward tools such as conductivity may not identify human influences in areas with saline groundwater inputs, diffuse exposure pathways, and few discharges of industrial wastewater. Researchers have further suggested in conductivity relative to alkalinity may also reveal human influences, but little has been done to evaluate the utility and necessity of this approach. Using data from 16 example sites in the Peace, Athabasca, and Slave Rivers in northern Alberta (but focusing on tributaries in Canada’s oil sands region) available from multiple regional, provincial, and national monitoring programs, we calculated residual conductivity and determined if it could identify the potential influence of human activity on streams in northern Alberta. To account for unequal sampling intervals within the compiled datasets, but also to include multiple covariates, we calculated residual conductivity using the Generalized Estimating Equation (GEE). The Pearson residuals of the GEEs were then plotted over time along with three smoothers (two locally weighted regressions and one General Additive Model) and a linear model to estimate temporal patterns remaining relative to known changes in human activity in the region or adjacent to the study locations. Although there are some inconsistencies in the results and large gaps in the data at some sites, many increases in residual conductivity correspond with known events in northern Alberta, including the potential influence of site preparation at oil sands mines, reductions in particulate emissions, mining, spills, petroleum coke combustion at one oil sands plant, and hydroelectric development in the Peace basin. Some differences in raw conductivity measurements over time were also indicated. Overall, these analyses suggest residual conductivity may identify broad influences of human activity and be a suitable tool for augmenting broad surveillance monitoring of water bodies alongside current approaches. However, some anomalous increases without apparent explanations were also observed suggesting changes in residual conductivity may also be well-suited for prompting additional and more detailed studies or analyses of existing data.

Aircraft engine particulate matter emissions from sustainable aviation fuels: Results from ground-based measurements during the NASA/DLR campaign ECLIF2/ND-MAX

The use of alternative jet fuels by commercial aviation has increased substantially in recent years. Beside the reduction of carbon dioxide emission, the use of sustainable aviation fuels (SAF) may have a positive impact on the reduction of particulate emissions. This study summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany. Two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) were burned in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic content and the corresponding fuel hydrogen content on non-volatile particle number and mass emissions. Reductions up to 70% in non-volatile particle mass emission compared to the fossil reference fuel were observed at low power settings. The reduction trends to decrease with increasing power settings. The fuels showed a decrease in particle emission with increasing fuel hydrogen content. Consequently, a second fossil fuel with similar hydrogen content as one of the HEFA blends featured similar reduction factors in particle mass and number. Changes in the fuel naphthalene content had significant impact on the particle number emission. A comparison to in-flight emission data shows similar trends at cruise altitudes. The measurements highlight the importance of individual fuel components in regulating engine emissions, particularly at the low thrust settings typically employed during ground operations (e.g. during idle and taxi). Therefore, when selecting and mixing SAF blends to meet present fuel-certification standards, attention should be paid to minimizing complex aromatic content to achieve the greatest possible air quality and climate benefits.

Comparison of the emission potential of renewable fuels in mono- and bi-fuel systems from the point of view of a car fleet in an incoming circular economy

The aim of the study is to investigate the most effective approach to reduce the emissions of a SI-engine while using a limited amount of renewable fuel. In this study, the renewable fuels ethanol, methanol, 2-ethoxy-2-methylpropane (ETBE), acetone, and dimethylformamide (DMF) were investigated with various fixed admixture rates and with a fully variable on-board fuel mixture (Smart-Fuel concept). One result of the study is that for a Smart-Fuel concept using methanol a reduction in CO2 emissions of approx. 12.5% and a reduction in particulate emissions of approx. 60% can be achieved, when considering an entire car fleet. In terms of engine efficiency, as well as particulate emissions, the pure substances, except DMF, achieved significant improvements compared to standard gasoline. Compared with the pure substances, the Smart-Fuel concept achieved lower advantages; however, it used significantly less scarcely available renewable fuel in the process. Based on the limited availability of renewable fuels within the first stages of a circular economy, the Smart-Fuel concept proves to be a very efficient transition technology to achieve the CO2 reduction targets. The Smart-Fuel concept only uses renewable fuel when it is worthwhile in terms of efficiency or emissions. Predefined fuel blends in a mono-fuel concept offer much less reduction potential in terms of emissions than the Smart-Fuel concept. However, with respect to particulate raw emissions, especially for moderate mixing rates significantly increased particle emissions are sometimes observed, despite the overall very good performance of the pure substances.

Hybrid dynamic coal blending method to address multiple environmental objectives under a carbon emissions allocation mechanism

The rise in global carbon emissions has led to serious ecological problems and highlighted the need to better pursue the sustainable development of coal-fired power plants. To reduce environmental pollution, this paper proposes a hybrid dynamic coal blending method under an uncertain environment to achieve a trade-off between economic development and environmental protection. This method fully considers seasonal pollutant variations, a dynamic carbon emissions quota allocation mechanism. A practical case from the Jintang coal-fired powered plant is given to verify the efficiency and practicality of the proposed optimization method. The model allows decision-makers to promote cleaner production by developing coal blending schemes to suit relevant national and local carbon and inhalable particulate matter emissions reduction policies. The results of the sensitivity analysis also confirm this view and show that the model is stable and has emission reduction limits. Specifically, compared with the maximum emissions, the model can reduce carbon emissions by about 29.1% (2.625 × 106 tonnes) and inhalable particulate matter emissions by 29.7% (0.64 × 106 tonnes). The results demonstrated that the hybrid dynamic coal blending method was able to achieve carbon emissions and inhalable particulate matter emissions reductions and that appropriate environmental constraints can improve emissions performance and encourage sustainable CPP development.

Don't extinguish my fire – Understanding public resistance to a Swedish policy aimed at reducing particle emissions by phasing out old wood stoves

Wood stoves emit particulate matter when used for domestic heating. Consequently, the National Board of Housing, Building and Planning in Sweden enforced a prohibition of new installations of old wood stoves in 2017 to protect the public health. The prohibition caused a public backlash that organized itself as a “wood stove rising”, eventually leading to a cancellation of the new legislation in 2019. We performed comprehensive interviews with 11 signatories of the original appeal to analyze the underlying motives for combating the implementation of this pro-environmental energy policy. We find that domestic heating through fire-making is an age-old human behavior that is deeply connected to several social and emotional human needs, but also to survival in remote areas with cold climate. The likelihood of policy observance and acceptance is higher if the policy is not perceived as being in direct conflict with these needs: basic emotion regulation, sensations of tradition and connection to other people, and means of crisis management for the individual. We also find that the protesters acted out of a sustainability perspective, albeit one where the continued use of functional devices was valued more than the perceived wear-and-tear of replacing outdated technology.

Flame confinement in biomass combustion systems for particles abatement

This work explores the use of open-pore, inert ceramic foams with different pore sizes as particle abatement systems in small biomass combustion systems. Porous foams made of silicon carbide with pore sizes 10 to 60 pores-per-inch were installed in an in-house designed combustion unit operated with wood pellets. Their effects on the temperature distribution inside the chamber, particulate and gases emissions were studied using different airflow rates in the reaction-limited regime (low equivalence ratio) to minimise stoichiometric factors. The influence of pore size, foam position with respect to the flame and space velocity were assessed. The confinement of the flame with inert foams was found to substantially modify the temperature distribution in the combustion chamber, improve the air-fuel mixture, and favour the thermal decomposition of the pellet, leading to a reduction in particulate emissions when compared to free-flame combustion at the same experimental conditions. In general, the amount of particulate matter was found to decrease by up to one order of magnitude as the pore size of the foam was reduced, while the temperature gradient in the combustion chamber was increased. Nitrogen oxides and carbon dioxide emissions were essentially unchanged, irrespectively of the pore size of the foam. It is expected that these values will be improved with longer residence times, as happens in operations with reduced excess air ratios. These results suggest that it is possible to control pollutants derived from domestic heating within the most restrictive current regulations on particulate emissions by integrating flame confinement designs with better operating practices and efficient abatement systems.

Influence of post-injection parameters on the performance of continuous regeneration trap to mitigate greenhouse gas and particulate emissions from CI engine

The present study explores the influence of post-injection parameters, namely, post-injection angle and post-injection mass, on a continuous active regeneration trap to mitigate vehicular emissions using diesel enriched by active amyl alcohol from Scenedesmus quadricauda microalgae. From the study, while operating on active amyl alcohol-diesel blend, the maximum de-smoke efficiency for low, medium and high load conditions observed were 67.25%, 55.78% and 46.94% respectively at a post-injection timing of 20°CA aTDC and at a post-injection mass of 2 mg. Furthermore, the maximum de-hydrocarbon efficiency was obtained at a post-injection timing and mass of 10°CA aTDC and 1 mg with a reduction of about 65.45%, 75% and 73.8% for low, medium and high load conditions. However, a 1.36% increase in fuel consumption is observed at late post-injections as compared to diesel fuel. At all cases, simultaneous reduction of particulate smoke emissions and oxides of nitrogen of up to 65.45% and 29% were observed with the complete elimination of carbon monoxide emissions by catalytic oxidation treatment within the after-treatment unit. The novelty of this study is to establish third generation bio-energy as a suitable diesel fuel surrogate for a post-injection activated after-treatment unit.

Gasoline powertrain solutions with ultra low tailpipe emissions

The introduction of Euro 6d legislation brought into law the regulation of particulate number and nitrous-oxide emissions under road-driving conditions. In line with these regulations, driving conditions involving highly dynamic, low ambient temperatures, and high vehicle loads are to be given particular attention. This leads to new challenges to the gasoline engine, the mixture preparation, and the exhaust-gas treatment. In the past, refinements made to the fuel-injection system have already resulted in significant progress being made in the reduction of particulate emissions. Supplemented by a latest-generation particulate filter, particulate emissions are now being continuously decreased. Gaseous emissions are reduced by combining innovative measures inside the engine itself with effective exhaust-gas treatment. The target of this investigation is the evaluation of innovative emission reduction measures in a demonstrator vehicle with a gasoline powertrain. For lower engine out emissions a fast heated air-fuel-ratio-sensor, new injection system with higher pressure, enhanced injection strategy with up to 7 injections per stroke, optimized calibration has been implemented. A gasoline particle filter, higher precious metal load of the three-way-catalyst, a second three-way-catalyst in underbody position and a burner for fast heat up of the exhaust system, leads to higher efficiency of the exhaust aftertreatment system. Among the development, particular emphasis is placed on minimizing the share of emissions during cold starts and the engine's warming-up phase. Emissions produced during the phase when engine and exhaust system are cold, are crucial to the total emissions during a trip. Innovative approaches, such as an expanded hybrid operating strategy and catalyst heating systems, are also assessed. The full integration of all emissions measures and precise adaptation in the interaction among these will open up further potential for reduction. The equipped with the measures pointed above can achieve values for particulate number and gaseous emissions amounting around 20% of the figures demanded by law. This low level of emissions achieved was confirmed and validated through challenging test cycles on a dynamometer at low temperatures and additionally in comprehensive road trails. The influence of such vehicles on air quality becomes negligible. True to its motto of “technology invented for life”, BOSCH is endeavoring to spur these developments on.

Optimising microscopic spray characteristics and particle emissions in a dual-injection spark ignition (SI) engine by changing GDI injection pressure

Regarding reducing particle emissions from dual-injection spark ignition engines, most of the existing research focused on the benefits of using alcohol fuels. However, a comprehensive study of the effects of fuel injection pressure on microscopic spray characteristics and particle emissions in dual-injection spark ignition engines fuelled with gasoline has not been reported before. In this paper, with the assistance of phase Doppler particles analyser system and fast particle analyser, a study of optimising microscopic spray characteristics and particle emissions in a dual-injection spark ignition engine fuelled with gasoline by changing GDI injection pressure was conducted. The results show that by increasing injection pressure from 5.5 to 18 MPa, both normal and tangential components of droplet velocity increase, but the possibility of spray impingement would not increase a lot. Higher injection pressure would increase the probability of small droplets, and more droplets would collapse with a mode of continuous ripping or break down abruptly. From jet’s central axis to sides, Sauter mean diameter increases first, then reduces outside the spray boundary. Increasing injection pressure from 5.5 to 18 MPa reduces total particle number concentration, which is 53.98% and 45.44% at 2 bar and 10 bar, respectively. Meanwhile, the peak of particle number distribution curve decreases from 3.01 × 106 to 1.43 × 106 at 2 bar, whilst reducing from 1.08 × 106 to 5.33 × 105 at 10 bar. Overall, this paper comprehensively analyses the effects of fuel injection pressure on microscopic spray characteristics and particle emissions, whilst offering a practical approach to reduce particle emissions in dual-injection SI engines fuelled with gasoline.

Future emissions of particles and gases that cause regional air pollution in California under different greenhouse gas mitigation strategies

Mitigating future climate change and managing future air quality are inter-related fields that have the potential to benefit from coordinated strategies that leverage the efforts in one area to achieve positive outcomes in the other area. California plans to reduce greenhouse gas (GHG) emission by 80% (relative to year 1990) by the year 2050. The changes required to meet this target also have the potential to improve air quality. Previous work developed an energy-economic model CA-TIMES and an emission inventory model CA-REMARQUE to study the possible pathways of meeting the GHG mitigation target and the air pollutant emissions associated with those pathways. Here we update the CA-TIMES and CA-REMARQUE model framework and analyze six different scenarios: (i) BAU - a business-as-usual future reference scenario, (ii) CAP30 - a loose GHG reduction scenario that meets current policy references but only achieves a 40% GHG reduction (relative to 1990 levels) by the year 2030, (iii) GHGAi - a climate-friendly 80% GHG reduction scenario featuring broad adoption of advanced technologies and renewable energies, (iv) CCS - a scenario that achieves 80% net GHG reductions but allows for more fossil energy combustion by focusing on adoption of carbon capture and sequestration technology, (v) NGB– a variation on the GHGAi scenario that allows for more natural gas combustion for residential and commercial buildings, and (vi) NGT – a variation of the GHGAi scenario that allows for more natural gas combustion for electricity generation. Results show that the GHGAi deep GHG mitigation scenario significantly reduces emissions (−41% PM0.1, −8% PM2.5, and −26% NOX) and improves air quality (−1 μg m−3 PM2.5) yielding public health benefits (+USD 20B yr−1) relative to the BAU scenario. The CCS scenario achieves the same GHG reductions but increases emissions in some areas (+2.5% PM2.5) resulting in only one third of the public health benefits compared to the GHGAi scenario. The NGB and NGT scenarios show that an 18% increase in natural gas utilization in buildings or a 15% increase in natural gas power generation offsets 32% and 46% of the ultrafine particle emission reduction achieved in the GHGAi scenario but has little impact on PM2.5 concentrations, producing approximately 90% of the public health benefits of the GHGAi scenario. These public health benefits should be considered when making decisions about future GHG mitigation strategies.

Investigation of the combustion and particle emission characteristics of a GDI engine with a 50 MPa injection system

The effects of injection pressure and injection timing are investigated in a gasoline direct injection engine with a 50 MPa injection system at part-load operating condition by experimental methods. The engine was invariably operated in stoichiometric air/fuel ratio, 1500 r/min engine speed and 5–15 bar break mean effective pressure (BMEP). The characteristics of combustion, particle size distribution (PSD) and particle number (PN) concentration of the emission are analyzed. The results indicate that delaying the injection timing can suppress the knocking tendency at higher engine loads, and significantly reduce fuel consumption, but the delayed injection increases particle emission. With the fuel injection pressure increased from 35 MPa to 50 MPa, the PN of all particle size segments are significantly reduced. High injection pressure has a significant effect on reducing the accumulation particles, and the PN concentration is reduced by more than 20%. The particles with a diameter of 5–23 nm (sub-23 nm) are a problem that cannot be ignored, which accounts for more than 50% of the total PN emission. A high fuel injection pressure can effectively reduce particulate matter emissions caused by late injection, thereby achieving both fuel consumption and particle emission reduction.