Reduction Of Nitrogen Oxide Emissions Research Articles

Important Contributions to Reducing Nitrogen Oxide Emissions from Internal Combustion Engines.

Nitrogen oxides are considered significant pollutants because of their effects on ecosystems and human health. The amount of NOx emitted by internal combustion engines can be reduced, mostly by acting on the conditions in which combustion takes place, respectively by lowering the peak flame temperature, reducing the excess of oxygen, etc. The homogeneous charge compression ignition (HCCI) engine represents a new technology that can simultaneously reduce NOx emissions and fuel consumption. This article presents these benefits of the HCCI engine by comparing the emissions and fuel consumption of a monocylinder engine when it is operated in a conventional way, with spark ignition, with those obtained when the engine is running in the HCCI mode. Moreover, since engine simulation has become an important tool for investigating the HCCI process and for developing new control strategies for it, this was used in this study to determine the effects of the exhaust gas recirculation on the combustion quality, respectively, on emissions.

Forty years of road transport NOX emissions reductions in the contiguous United States: an environmental justice analysis

BACKGROUND AND AIM: Road transport-related nitrogen oxide (NOX) emissions in the United States (US) were drastically reduced over the last forty years. These improvements were mainly driven by environmental policies aiming to reduce emissions and, consequently, exposure to air pollutants. Prior research has identified inequalities in air pollution exposures in the US but, to our knowledge, no studies have evaluated potential disparities in emissions reductions across the country. We aim to describe the nationwide distribution of NOX emission reductions from 1970 to 2010 by race/ethnicity and socioeconomic status. METHODS: We conducted analyses at the county level from 1970 to 2010 across the contiguous US. We used annual NOX transport emissions estimated by a global emissions inventory model at 50km2 grid resolution, which we aggregated to area-weighted county averages. We obtained annual county-level race/ethnicity, education, family income, poverty, unemployment, and house value data from decennial Census and the American Community Surveys. We used a mixed-effects model with random intercepts for counties nested within states to estimate the change in kg/km2/day in emissions between decades, given county socio-demographics. RESULTS:On average, annual road transport NOx emissions in the US have decreased by 42% between 1970 and 2010. We found that a one standard deviation (SD) increase in the percent White or Black population was associated with an increase in the reduction of NOx emissions (β=0.48, 95%CI: 0.37, 0.59 and β=0.45, 95%CI: 0.35, 0.56 respectively). Conversely, one SD increased in percent poverty or unemployment was associated with a decrease in the emissions reduction (β= -0.17, 95%CI: -0.19, -0.14 and β= -0.02, 95%CI: -0.04, -0.004 respectively), that is, a smaller reduction in NOx emissions. CONCLUSIONS:Our preliminary results suggest that the decreases in road transport NOx emissions over the last decades may vary across counties based on socio-economic and demographic characteristics. KEYWORDS: Oxides of nitrogen, air pollution, environmental justice, environmental disparities, policy

Analysis of effective factors on technology selection and ranking of nitrogen oxide emission reduction technologies (Case study: Iranian thermal power plants)

Background and purpose: Thermal power plants play a major role in the production of air pollutants with significant consumption of fossil fuels. Sulfur oxides are among these pollutants. Regarding the necessity of reducing pollutants due to combustion of fuel in power plants of Iran this paper proposes a solution to select NOx reduction technology with investment approach in Iranian thermal power plants. Method:In this research, first with the extensive knowledge of research conducted in this field, the existing technologies in the world and also the most important criteria effective in their effectiveness have been identified and in the next step in order to adapt these criteria to Iran's conditions, from Fuzzy Delphi technique was used to finalize the criteria. In order to weigh the criteria and then rank the existing technologies, the new SECA ranking technique is used. Finding: . The results showed that IFGR technology, OFA, Flameless Combustion, LNB and FR(Fuel reburning) were the first to fifth priority of technology selection, respectively. Discussion and Conclusions: Together, these technology assessments will help create a more environmentally friendly and sustainable environment and make the ecological systems less vulnerable.

Investigation into engine performance of a hydrogen-dimethyl ether spark-ignition engine under various dimethyl ether fractions

Spark-ignition combustion mode could be used to widen the operation range of homogeneous charge compression ignition combustion mode on a hydrogen-dimethyl ether (DME) engine. To improve power output and reduce nitrogen oxides emissions, this study investigated the combustion and emissions properties of a hydrogen-DME spark-ignition engine under various DME fractions (αDME). The result showed that flame development and propagation periods were extended after DME blended. The increases of both periods were 1.7 and 2.0 °CA when αDME various from 1.4% to 3.0%, respectively. However, when αDME increased to 3.4%, flame propagation period had a 1.7 °CA reduction because of the spontaneous high-temperature oxidation of a few end unburned mixtures. Blending DME could improve power output of the neat hydrogen engine. The maximum improvement of indicated mean effective pressure could achieve 18.3%, after DME addition. Because of the weakened flame kernel and flame propagation process, when αDME lower than 3.0%, blending DME increased cyclic variation yet the variations were in 0.13%. Nitrogen oxides emissions could be reduced significantly, when DME was added into the neat hydrogen engine. The maximum reduction could achieve 49.9%, based on neat hydrogen fuel-supply mode. Hydrocarbon and carbon monoxide emissions were increased after DME addition. When αDME increased from 1.4% to 3.4%, the enhancement of hydrocarbon emissions was about two-third lower than that of carbon monoxide emission.

The response of streams in the Adirondack region of New York to projected changes in sulfur and nitrogen deposition under changing climate

Modeling studies project that in the future surface waters in the northeast US will continue to recover from acidification over decades following reductions in atmospheric sulfur dioxide and nitrogen oxides emissions. However, these studies generally assume stationary climatic conditions over the simulation period and ignore the linkages between soil and surface water recovery from acid deposition and changing climate, despite fundamental impacts to watershed processes and comparable time scales for both phenomena. In this study, the integrated biogeochemical model PnET-BGC was applied to two montane forest watersheds in the Adirondack region of New York, USA to evaluate the recovery of surface waters from historical acidification in response to possible future changes in climate and atmospheric sulfur and nitrogen deposition. Statistically downscaled climate scenarios on average project warmer temperatures and greater precipitation for the Adirondack by the end of the century. Model simulations suggest under constant climate, acid-sensitive Buck Creek would gain 12.8 μeq L−1 of acid neutralizing capacity (ANC) by 2100 from large reductions in deposition, whereas acid insensitive Archer Creek is projected to gain 7.9 μeq L−1 of ANC. However, climate change could limit those improvements in acid-base status. Under climate change, a negative offset relative to the ANC increases with no climate change are projected for both streams by 2100. In acid-insensitive Archer Creek the negative offset (−8.5 μeq L−1) was large enough that ANC is projected to decrease by −0.6 μeq L−1, whereas in acid-sensitive Buck Creek, the negative offset (−0.4 μeq L−1) resulted in a slight decline of the projected future ANC increase to 12.4 μeq L−1. Calculated target loads for 2150 for both sites decreased when future climate change was considered in model simulations, which suggests further reductions in acid deposition may be necessary to restore ecosystem structure and function under a changing climate.

Emissions from homogeneous charge compression ignition (HCCI) engine using different fuels: a review.

The main objective of this paper is to review the emission characteristics of homogeneous charge compression ignition (HCCI) engines using different fuels and additives. Additionally, the impacts of various operating conditions on HCCI engine emissions are also analyzed. There is a demand faced by the engine and car manufacturers for high fuel efficiency and low emission from both consumers and the government. HCCI is an alternative internal combustion technology that is more efficient and cleaner than traditional combustion techniques. In this engine, fuel and oxidiser (typically air) are entirely mixed and compressed to the point of auto-ignition. It is a new combustion concept that provides high efficiency and resolves high nitrogen oxide (NOx) and particulate matter (PM) emissions simultaneously. Conventional diesel engine emits NOx around 2000-2500 ppm which is a primary concern; however, when diesel is used in HCCI engine, it reduces NOx to only 70-400 ppm. Furthermore, natural gas cannot be used as fuel in the conventional engine but can be used in HCCI engine. It helps reduce NOx emission even below 10 ppm. This paper reviews several works done by researchers on HCCI engines to reduce their emissions and benefit future research.

Prediction of hydrogen-heavy fuel combustion process with water addition in an adapted low speed two stroke diesel engine: Performance improvement

Despite their high thermal efficiency (>50%), large two-stroke (2 T) diesel engines burning very cheap heavy fuel oil (HFO) produce a high level of carbon dioxide (CO2). To achieve the low emission levels of greenhouse gases (GHG) that will be imposed by future legislation, the use of hydrogen (H2) as fuel in 2 T diesel engines is a viable option for reducing or almost eliminate CO2 emissions. In this work, from experimental data and system modelling, an analysis of dual combustion is carried out considering different strategies to supply H2 to the engine and for different H2 fractions in energy basis. Previously, a complete thermodynamic model of a 2 T diesel engine with an innovative scavenging model is developed and validated. The most important drawbacks of this type of engines are controlled in this work using dual combustion and water injection, reducing nitrogen oxides emissions (NOx), self-ignition and combustion knocking. The results show that the developed model matches engine performance data in diesel mode, achieving a higher efficiency and mean effective pressure (MEP) in hydrogen mode of 53% and 14.62 bar respectively.

State-by-State comparison of combined heat and power to photovoltaic installations at manufacturing facilities with heat and power loads

Manufacturing facilities with large electricity and steam loads commonly meet those loads with a grid and boiler (GB) system configuration. In this study, two alternatives, a natural gas turbine cycle driven combined heat and power (CHP) system configuration and a grid boiler system augmented with photovoltaics (GB-PV), are investigated sustainable manufacturing in reference to the GB system configuration. For this purpose, their discounted payback period (DPP), carbon dioxide (CO2) and nitrogen oxides (NOx) emission reductions, and primary fossil energy impacts are calculated. The major contribution of this study is that it directly compares the application of both CHP and PV technologies at an assumed manufacturing facility in all 50 states of the United States. This highlights the location-specific impacts of the facility. The examined manufacturing facility utility requirements are 5 MW of power and over 12,000 kg/h of 250 kPa and 400 K saturated steam. A DPP of less than 25 years, the technology lifetime, is found in 44 states for the CHP system configuration and 6 states for the GB-PV system configuration. GB-PV and CHP cost-effectively reduce CO2 in 44 and 38 states, respectively. CHP is better for NOx reduction, whereas GB-PV is better for primary fossil energy reduction.

Trends in the Reduction of Nitrogen Dioxide Emissions: Effect of 2020 SARS-CoV-2 Pandemic Versus Emission Reduction Regulations

Nitrogen Dioxide is primarily emitted to the atmosphere through the combustion of fossil fuels, and the measurement of its emission serves as the indicator for the emission of the group of nitrogen oxides (NOx), which have adverse effects on health, environment, and climate. Over the past few decades, countries around the world have enacted policies to reduce the emission of air pollutants and greenhouse gasses. In 2019, NOx concentration in the United States was 62% lower than the 2002 levels. Therefore, when studying the impact of sporadic events such as COVID-19 restrictions on emissions, it is necessary to account for such ongoing reductions. Using Sentinel-5P satellite and twenty-six roadside ground monitors, we studied the change of NO2 concentration in the US Northeast megapolis. Using the National Emission Inventory (NEI) report on total NOx emissions (stationary and mobile) and the US EPA Motor Vehicle Emission Simulator (MOVES), we quantified the reduction of total NOx emissions and those from mobile sources for the study region. We find that the pandemic resulted in a 3.4% reduction of total NOx emissions. This is compared to (and in addition to) the expected 8.2% reduction, which has been persistently occurring over the past decade as the result of the Clean Air Act, and which would have taken place even in the absence of the pandemic. When considering NOx emissions from mobile sources only, the pandemic resulted in a 5% reduction of NOx emissions, compared to (and in addition to) the expected 10.9% policy-driven reduction. Using mobility data from the Apple Corporation and roadside vehicle count sensors, we find that the volume of freight traffic, the principal source of mobile emissions, reduced considerably less than automobile traffic volume during the pandemic restrictions. We believe this is the primary contributing factor to the relatively low pandemic-related reduction of NO2 emissions.

Chinese Regulations Are Working—Why Is Surface Ozone Over Industrialized Areas Still High? Applying Lessons From Northeast US Air Quality Evolution

AbstractObservational data indicate increasing trends of surface ozone (O3) in China, despite emission controls that have resulted in reductions of precursor emissions. Here, we explore the cause of this contradiction, through analysis of surface observations (2014–2019) in China and historical observation record in the United States (US, 1990–2019). Our observation‐based analysis indicates that the reductions of nitrogen oxides (NOx) emissions led to increase of surface O3 in North China Plain (NCP) and Yangtze River Delta (YRD) of around 8 ppb. However, NOx controls resulted in shift of O3 chemical regimes over NCP and YRD, with turning points between NOx‐ and volatile organic compound (VOC)‐limited regimes around 2019, while model simulations suggest transitional or NOx‐limited regimes over the rest of China. The impacts of high fine particles (PM2.5) on O3 formation has declined because of the reduction of PM2.5 concentrations. Stricter NOx controls can mitigate O3 pollutions over industrialized areas in China.

NOx Emission from Diesel Vehicle with SCR System Failure Characterized Using Portable Emissions Measurement Systems

Nitrogen oxides (NOx) emissions from diesel vehicles are major contributors to increasing fine particulate matter and ozone levels in China. The selective catalytic reduction (SCR) system can effectively reduce NOx emissions from diesel vehicles and is widely used in China IV and V heavy-duty diesel vehicles (HDDVs). In this study, two China IV HDDVs, one with SCR system failure and the other with a normal SCR system, were tested by using a portable emissions measurement system (PEMS). Results showed that the NOx emission factors of the test vehicle with SCR system failure were 8.42 g/kW∙h, 6.15 g/kW∙h, and 6.26 g/kW∙h at loads of 0%, 50%, and 75%, respectively, which were 2.14, 2.10, and 2.47 times higher than those of normal SCR vehicles. Emission factors, in terms of g/km and g/kW∙h, from two tested vehicles were higher on urban roads than those on suburban and motorways. The NOx emission factor of the vehicle with failed SCR system did not meet the China IV emission standard. The time-weighted results for normal SCR vehicle over the three road types show that, except for NOx emission factor 12.17% higher than the China IV limit at 0% load, the emission values are 16.21% and 27.54% below the China IV standard limit at 50% load and 75% load, respectively. In general, with higher load, NOx emissions (in terms of g/kW∙h) from the tested vehicle decreased. Furthermore, NO/NOx concentrations of both vehicles with normal and failed SCR systems showed a decreasing trend with the increase in load.

Impact of injection timings and exhaust gas recirculation rates on the characteristics of diesel engine operated with neat tamarind biodiesel

ABSTRACT The extensive usage of petroleum products in the power sector, industries, and transportation may lead to the depletion of fossil resources. Also, the most important human challenges of the 21st century are global warming and climate changes due to increased pollution levels. Nowadays, the need for new energy sources is one of the foremost problems of all countries in the world. The current experimental work is primarily focusing on the exploration of neat tamarind seed methyl ester (TSME) as a sustainable energy source for diesel engines. All the physicochemical properties were determined experimentally with concern to ASTM standards and compared with diesel fuel. Initially, tests were performed on a diesel engine with diesel and neat tamarind biodiesel in standard operating conditions 23º CA bTDC. Later, the injection timing was varied like 19º CA bTDC and 27º CA bTDC for the neat tamarind biofuel. A test result found with TSME biofuel that enhancement in brake thermal efficiency (BTE) by 4.07% was achieved with the retardation of engine injection timing when compared to standard injection timing. Also, it was found that drastic reduction of exhaust emissions by 9.7%of CO, 15.8% of HC and 6% of SO have resulted in the retarded injection timing of TSME when compared to standard conditions of TSME at full load. However, the oxides of nitrogen emissions were increased. To control the oxides of nitrogen emissions, exhaust gas recirculation (EGR) at two levels such as 10% and 20% were used when the engine was operated at retarded injection timing (IT) with TSME. It was found that TSME with 10% EGR inferred a drastic reduction of nitrogen oxide emissions by 30% and 37.7% over diesel and TSME, respectively, at full load.

Reducing diesel exhaust emissions by optimisation of alcohol oxygenates blend with diesel/biodiesel

Biodiesel is substantially found to reduce carbon dioxides, hazardous particulate matter but increasing anthropogenic nitrogen oxides (NOx) emissions. Fuel blending with alcohol oxygenate is one of the best NOx mitigation technologies. The objective of this present study is to develop a model-based product design optimisation of diesel/biodiesel/alcohol blends incorporated with an accurate NOx prediction model as the model's predictive accuracy. The compositions for each fuel blend are deliberately formulated via systematic Linear Programming. The effects of cetane number, oxygen content, and heat of vaporisation have been evaluated. Performance, combustion characteristics, and environmental impact of the fuel blends were compared to diesel standard, which complies with the fuel regulation: ASTM D975 and EN590 standards. The result depicted that 70% diesel, 20% biodiesel, and 10% butanol is the optimal blend with the similar performance (power output) as diesel, lowest cost, and NOx emissions reduction from 7% up to 15%. The increase of oxygen content causes a stronger cooling effect to reduce the NOx pollutant emissions. The NOx formation prediction has been performed by adopting the fuel blend properties, including cetane number, and oxygen content using a rigorous approach. The NOx formation prediction has been performed by adopting the fuel blend properties, including cetane number and oxygen content, using a rigorous approach. The final NOx prediction models developed can be a precursor to implementing the physical system in a dynamic testing phase. Higher alcohol (butanol) offers superior characteristics such as higher HOV (stronger cooling effect to reduce NOx formation), CV (higher power output), CN (reduces ignition delay), density and viscosity (better fuel flow for better atomisation), and flash point (for safer storage and handling) as compared to lower alcohol like ethanol. Conclusively, diesel/biodiesel/butanol enhances the HOV, which leads to a stronger cooling effect in the combustion chamber, thus reducing NOx formation.

Surface ozone in the North American pollution outflow region of Nova Scotia: Long-term analysis of surface concentrations, precursor emissions and long-range transport influence

Nova Scotia is in the air pollution outflow region of North America and experiences elevated surface air pollution episodes regularly. We present the first analysis of long-term (2000–2018) hourly ozone (O3) and ozone precursor gas trends at three Nova Scotia provincial monitoring locations (‘urban’ Halifax, ‘suburban’ Halifax at Lake Major and ‘regional background’ at Aylesford Mountain), together with an examination of provincial ozone precursor emission trends. The precursors considered are nitrogen oxides (NOx) and volatile organic compounds (VOC). Over the common data period for the three stations (2006–2017) the annual 99th percentile hourly ozone concentrations decreased significantly in Halifax (−0.77 ppb/year; p = 0.02) and at Aylesford (−0.65 ppb/year; p = 0.03), in agreement with regional trends. No statistically significant changes were found in high ozone at suburban Lake Major (−0.02 ppb/year; p = 0.94), but the annual 25th percentile, median, and 75th percentile hourly ozone concentrations increased significantly (p < 0.01) only at this location (1.09 ppb/year, 1.23 ppb/year, 1.03 ppb/year, respectively). This is consistent with the strong NOx-O3 titration effect in downtown Halifax decreasing over time. After correcting for the titration effect over the full study period, the annual median Halifax total ozone is found to be decreasing (−0.45 ppb/year; p = 0.02).Over the full study period, ambient concentrations of precursors decreased significantly (p < 0.01) in Halifax by −2.34 ppb/year for NOx and −3.41 μg/m3/year for VOCs, as did the ozone formation potential (OFP) of VOCs (−9.66 μg/m3/year; p < 0.01). The underlying emissions of precursors also decreased significantly (p < 0.01) in and near Halifax (provincial NOx: 3982 ppb/year; provincial VOCs: 1680 tonnes/year), also in agreement with regional trends. However, a linear regression during 2012–2018 showed a decelerating reduction of provincial NOx emissions. Provincial total VOC emissions also decreased approximately ten times slower during 2012–2018, albeit this was not statistically significant. Finally, we present an algorithm to identify events of long-range transported pollution in Halifax, based on spatial correlations in ozone across surface monitoring stations in Nova Scotia. Between 2000 and 2018, transported upstream pollution was found to be connected to between 45% and 63% of 1444 days when surface ozone was elevated in Halifax. The frequency with which transported pollution events occur increased by 15% across this time period.

An investigation on the performance and emission studies on diesel engine by addition of nanoparticles and antioxidants as additives in biodiesel blends

AbstractThe study aims to examine the effects of palm biodiesel blended with additives in the compression ignition (CI) engine. Biodiesel as fuel was limited by challenges such as lower calorific value (CV) and higher viscosity while increasing brake specific fuel consumption (BSFC) and nitrogen oxides (NOx) emissions. Nanoparticles and antioxidant additives added to biodiesel play an essential role in avoiding the hindrances of biodiesel. The antioxidants combined with biodiesel reduced NOx emissions by eliminating decomposing peroxides, free radicals, and preventing free radicals' chain reaction. The Significant characteristics of nanoparticles are high CV, high thermal conductivity, and higher surface to volume ratio. These characteristics are used to improve the CI engine's performance and emissions by using nanoparticles blended with biodiesel. Five different test blends of Diesel, B20, B20TO, B20AO, and B20AOTO were prepared. The result showed high brake thermal efficiency (BTHE) and decreased BSFC, exhaust gas temperature (EGT), hydrocarbons (HC), NOx, and HC emissions by using the B20AOTO fuel blend contrasted with other biodiesel blends.

Use of biogas containing CH4, H2 and C02 in controlled auto-ignition engines to reduce NOx emissions

The use of biogas in internal combustion engines presents many advantages. Nevertheless, the CO2 content in the fuel negatively affects the combustion process, reducing combustion speed and stability. The presence of hydrogen in the biogas would improve its combustion characteristics. This paper investigates the combustion of biogas in a Controlled Auto Ignition (CAI) engine by means of numerical simulations. A model of the combustion system was developed for analyzing the use of biogas in a Chemkin environment. The biogas considered in this paper naturally contains hydrogen as a result of a new anaerobic digestion process. The CAI internal combustion engine model allowed the evaluation of engine performance and emissions. Different hydrogen contents were investigated to find the optimal fuel composition for reducing nitrogen oxides emission. Exhaust Gas Recirculation (EGR) was adopted for controlling in-cylinder temperature and therefore fuel auto-ignition. In fact, the presence of very reactive chemical species in the EGR, such as nitric oxide (NO), resulted to have an important impact on the onset of combustion. The results demonstrated that biogas containing hydrogen allow a reduction of NOx emissions with respect to a conventional biogas. An optimal biogas composition was identified, allowing a 32% reduction in NOx emission compared to the conventional biogas. The reaction mechanism for NO formation did not change with biogas composition, with an important contribution coming from prompt NOx formation mechanism. The main differences were in the reaction rates, higher for the conventional biogas.

The Synergy of Two Biofuel Additives on Combustion Process to Simultaneously Reduce NOx and PM Emissions

The article presents the results of research on the influence of two fuel additives that selectively affect the combustion process in a diesel engine cylinder. The addition of NitrON® reduces the concentration of nitrogen oxides (NOx), due to a reduction in the kinetic combustion rate, at the cost of a slight increase in the concentration of particulate matter (PM) in the engine exhaust gas. The Reduxco® additive reduces PM emissions by increasing the diffusion combustion rate, while slightly increasing the NOx concentration in the engine exhaust gas. Research conducted by the authors confirmed that the simultaneous use of both of these additives in the fuel not only reduced both NOx and PM emissions in the exhaust gas but additionally the reduction of NOx and PM emissions was greater than the sum of the effects of these additives—the synergy effect. Findings indicated that the waveforms of the heat release rate (dQ/dα) responsible for the emission of NOx and PM in the exhaust gas differed for the four tested fuels in relation to the maximum value (selectively and independently in the kinetic and diffusion stage), and they were also phase shifted. Due to this, the heat release process Q(α) was characterized by a lower amount of heat released in the kinetic phase compared to fuel with NitrON® only and a greater amount of heat released in the diffusion phase compared to fuel with Reduxco® alone, which explained the lowest NOx and PM emissions in the exhaust gas at that time. For example for the NOx concentration in the engine exhaust: the Nitrocet® fuel additive (in the used amount of 1500 ppm) reduces the NOx concentration in the exhaust gas by 18% compared to the base fuel. The addition of a Reduxco® catalyst to the fuel (1500 ppm) unfortunately increases the NOx concentration by up to 20%. On the other hand, the combustion of the complete tested fuel, containing both additives simultaneously, is characterized, thanks to the synergy effect, by the lowest NOx concentration (reduction by 22% in relation to the base). For example for PM emissions: the Nitrocet® fuel additive does not significantly affect the PM emissions in the engine exhaust (up to a few per cent compared to the base fuel). The addition of a Reduxco® catalyst to the fuel greatly reduces PM emissions in the engine exhaust, up to 35% compared to the base fuel. On the other hand, the combustion of the complete tested fuel containing both additives simultaneously is characterized by the synergy effect with the lowest PM emission (reduction of 39% compared to the base fuel).

Performance and Emissions of Diesel Engine with Circulation Non-Surfactant Emulsion Fuel System

Diesel engine is known for its durable operation and capability of utilizing various type of fuels, however, dangerous exhaust emissions are emitted from diesel engines. Non-surfactant emulsion fuel is a potential fuel for diesel engine to reduce for Nitrogen oxides (NOx) and Particulate matter (PM) emission compare to conventional diesel fuel in a diesel engine. In this study, emulsion fuel was prepared using a mixer known as Circulation Non-Surfactant Emulsion Fuel System. The study carried out with different water percentages in the emulsion fuel given as follows: 3%, 6%, and 9% and at a different engine load condition from 1-4 kW with a constant speed of 3200 rpm. Results show that, 6% emulsion fuel shows average 4.38% reduction in NOx emission and 1.10% reduction in fuel consumption. 9% emulsion fuel show higher amount of CO emission compare to Diesel while it reduces CO2 emission. Overall, 6% when prepared are recommended for the formation of non-surfactant emulsion fuel.

Investigation of Solid Deposit Inside L-Type Urea Injector and NOx Conversion in a Heavy-Duty Diesel Engine

The heavy-duty diesel engine is used in the main transportation vehicles in Korea to deliver products from various companies; however, diesel engines produce enormous quantities of nitrogen oxide (NOx), which harms human health. The selective catalytic reduction (SCR) system is a common solution to reduce NOx emissions from diesel engines; however, heavy-duty diesel engines produce more NOx than can be dealt with using an SCR and thus require investigations into effective NOx reduction solutions. This study investigated 12,000 cc heavy-duty diesel engines from Hyundai using the 1000 rpm engine operation to produce 1330 ppm of NOx emission. The ammonia generation process was assessed by the amount of ammonia produced; the amount of ammonia gas was identified by 19 gas sensors on the catalyst surface; the effectiveness of the mixing process between the ammonia and the NOx in the system was determined by the NOx conversion values from a gas analyzer. Comparison between the experiment and simulation results shows the ammonia and NOx values and elucidates the temperature results for vaporization and saturation quantity, ammonia distribution, and NOx conversion in the system. The NOx conversion investigations also provide the chemical reaction and numerical equation relevant to the ammonia and NOx distribution.

Effects of EGR and Alternative Fuels on Homogeneous Charge Compression Ignition (HCCI) Combustion Mode

We present in this article an analysis of the impacts of the exhaust gas recirculation (EGR) and alternative fuels on HCCI combustion mode. The objective is to reduce the pollutant emissions below the levels of established pollution standards. The ANSYS CHEMKIN-Pro software and the combined chemical kinetics mechanism were used to perform simulations for a closed homogeneous reactor under conditions relevant to HCCI engines. The calculation process is based on one single-zone in the combustion chamber. Numerical simulation has proven the ability of the models adopted, which use the essential mechanisms of the fuel combustion process, to reproduce, among other things, the evolution of the formation of chemical species. This study showed that adding hydrogen (H2) to methane (CH4) is an interesting alternative fuel because it reduces ignition time. It was concluded that an increase of EGR rate conducts to a slower combustion process, lower temperatures, and the reduction of nitrogen oxide (NOX) emissions.