Unregulated Emissions Research Articles

Performance, regulated and unregulated exhaust emission of a stationary compression ignition engine fueled by water-ULSD emulsion

The interest in water-diesel emulsion fuel (EM) is increased recently because of the significant reduction in emissions from diesel exhaust, especially NOx and PM. In this study, a diesel engine configured for experimental investigations was fueled by ultra-low sulfur diesel (ULSD) and a diesel-water emulsion (EM). Both fuels’ combustion characteristics were studied at a speed of 1500 rpm and using a load of 2.5 and 5 bars and variable injection timings. Regular and irregular pollutants were studied at the same conditions as well as at variable engine loads and speeds to better understanding for their formation conditions. As for the first time (in the case of an engine running with a water-diesel emulsion) irregular pollutants for EM emulsion were measured.The measured results indicated that the use of water-diesel emulsion reduced the heat released in the combustion chamber, which causes an increase in the brake specific fuel consumption and ignition delay. For the tested loads, the diffusion combustion duration for EM was decreased when the injection timing was retarded while the opposite was occurred for premixed combustion duration. The regulated NOx and Smoke Number were reduced when EM was used compared to ULSD while CO and HC levels were increased at low engine’s speed and loads. Besides, these concentrations are depending on injection timing (they were higher at restarted timing). The unregulated emissions measured (Formaldehyde, Acetaldehyde, Methane, Acetylene, Ethylene, and propylene, Ammonia, and Acetone) were increased with using EM, especially at no and low loads, indicating the high impact of the combustion chamber temperature on these pollutants formation.

Numerical investigation of intake oxygen enrichment effects on radicals, combustion and unregulated emissions during cold start in a DISI methanol engine

Oxygen enrichment combustion is one of the attractive methods to improve combustion and reduce emissions in spark ignition engines. The effects of intake oxygen enrichment on intermediate radicals, combustion, and unregulated emissions of formaldehyde and unburned methanol during cold start were numerically calculated by using CFD simulation coupled with a detailed methanol chemical kinetic model for a DISI methanol engine. Results show that the concentration of OH, O, and H radicals during cold start is obviously increased and CA50 is slightly advanced with increase of intake oxygen concentration (CO2), resulting in accelerated chain reaction in methanol combustion, and further mitigating unburned methanol emissions. When CO2 varies from 21% to 36%, cylinder temperature increases due to the post-combustion. Cylinder temperature reaches the maximum value at 36% CO2. After further increasing CO2 to 41%, the in-cylinder temperature start to decrease as a result of the decreased OH concentration and inhibited post-combustion. In general, CO2 is the accelerant in formaldehyde formation at initial stage and in formaldehyde oxidization during post-combustion. By increasing CO2, formaldehyde emission rises and unburned methanol emission diminishes during cold start.

Climate-conscious consumers and the buy, bank, burn program

Manipulation of European Union emission trading systems (ETS) by the buy, bank, burn program compensates unregulated emissions while regulated sectors carry a large part of the burden. This distorts the balance between regulated firms and non-regulated projects, so parties outside the EU ETS can be virtuous at the cost of others.

Complex analysis focused on influence of biodiesel and its mixture on regulated and unregulated emissions of motor vehicles with the aim to protect air quality and environment

The main task of this study is to perform a complex analysis dealing with influence of biodiesel and its mixture on regulated and unregulated gaseous emissions of diesel engine, which is installed in a motorcar as a driving unit determined for standard road traffic. As a real technical platform intended for realisation of the required experiments, a motor vehicle equipped with the TDI engine was chosen because just this kind of engine was directly affected by the affair “dieselgate”. This type of piston combustion engine is widely used in the traffic, together with negative impacts on the air quality. Various diesel fuel mixtures, which represented the applied experimental fuels, were created by mixing of the ultra-low sulphur diesel fuel (ULSDF) with the biodiesel, using different mixture ratios. The individual experiments were performed during a 13-mode test cycle especially developed for the diesel engine in such a way, so that it was possible to identify influence of the engine loading and engine speed on the regulated and unregulated gaseous emissions of the given TDI diesel engine. It is possible to say according to the obtained results that a higher portion of the biodiesel in the fuel mixture reduces the amount of the hydrocarbons (HC), carbon monoxide (CO) and particulate matters (PM) in the gaseous emissions, but it increases volume of the nitrogen oxides (NOX). A higher portion of the biodiesel causes a growth of the formaldehyde emissions and acetaldehyde emissions in the case of unregulated diesel engine emissions. The same trend is also typical for the 1,3-butadiene, propene and ethene. The biodiesel additive increases emissions of benzene; however, it reduces emissions of the toluene and xylene within the aromatic substance emissions. The obtained results confirm a fact that all the gaseous emissions are influenced by the engine operational regimes, especially by the engine loading status.

Effect of n-butanol fumigation on the regulated and unregulated emission characteristics of a diesel engine

Many investigations have been carried on the utilization of ethanol and methanol fuels in diesel engine to study the performance and regulated emission characteristics. However, very few investigations are made with discussion on the unregulated emissions. So the present work is focussed on the investigation of performance and emissions (both regulated and unregulated) from premixed n-butanol vapours in a single cylinder, four stroke, direct injection diesel engine and the results are presented in this paper. In this work n-butanol was used as a fuel owing to its longer-chain structure compared to methanol or ethanol, resulting in a lower specific heat of vaporization and greater enthalpy of combustion, while lowering water susceptibility and greater possibility than ethanol or methanol fuel. Subsequently, n-butanol has properties considerably closer to diesel fuel than ethanol, rendering it best to mix or fumigated with normal diesel fuel. In this work, n-butanol is fumigated along with the air in three different volume percentages such as 10, 20 and 30. About 14.76% higher brake thermal efficiency was noticed when 20% n-butanol was fumigated compared with the neat diesel operation. The oxides of nitrogen, acetaldehyde and acrolene emissions are reduced by 11.4%, 20.08% and 40.81% respectively. However, the HC, CO, formaldehyde and acetone emissions are increased with increased percentages of n-butanol.

Effects of engine load and biodiesel content on performance and regulated and unregulated emissions of a diesel engine using contour-plot map

This experimental study was conducted to explore the favorable and unfavorable conditions which promote or reduce the performance and emissions in a diesel engine, based on six engine loads (5% to 95% load) and five biodiesel contents including B0 (0% waste cooking oil biodiesel and 100% diesel, by volume %), B20, B50, B75 and B100 (pure biodiesel), at a constant engine speed of 1920 rpm. According to the results, the maximum brake specific fuel consumption was recorded at the lowest engine load (5% load) using B100; while the highest brake thermal efficiency was obtained at 80% load for B100. In regard to regulated emissions, the highest engine load (95% load) with diesel fuel was the condition for the formation of maximum CO, smoke opacity, PM mass, total particle number concentration and geometric mean diameter. The 95% load with B100 was the condition for maximum CO2 and NOX. The 60% load with diesel fuel was the condition for maximum THC. For unregulated emissions, low engine load with B100 was the condition for maximum formaldehyde, acetaldehyde, ethene and propene. The maximum 1,3-butadiene was observed for B100 at 80% load. The highest benzene emission was recorded at 40% load for B100. The maximum toluene and xylene emissions were found at 5% load for diesel fuel. In addition, the conditions which lead to produce the minimum emissions are also extensively discussed in the present study.

Experimental Study on Unregulated Emissions Characteristics of Alcohol-Diesel Dual-Fuel Combustion with Diesel Oxidation Catalyst

AbstractAn experimental study has been conducted to investigate the effects of alcohol properties on dual-fuel (DF) combustion and unregulated emissions such as NO2, HCHO, and CH3CHO on a multicyli...

Evaluation of methyl ester derived from novel Chlorella emersonii as an alternative feedstock for DI diesel engine & its combustion, performance and tailpipe emissions

This work examines the feasibility of fueling methyl ester derived from green algae species, Chlorella emersonii in a compression ignition engine. This work also proposes Chlorella emersonii methyl ester (CEME) as a potential alternative energy source since the above species is available extensively in freshwater, marine and aquatic ecosystems throughout the world. CEME was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40% and 100% and their properties were analyzed as per ASTM standards for its application as biofuel. The prepared test fuels were analyzed experimentally in a single cylinder diesel engine at a constant speed (1500 rev/min) for its performance, combustion and emission (regulated and unregulated) characteristics. Test results indicated that, the characteristics of 20% CEME+80% DIESEL fuel blend was in par with neat DIESEL fuel in terms of thermal efficiency, THC (total hydrocarbon), CO (carbon monoxide) and smoke emissions. However, CEME blends resulted in slightly higher levels of CO2 (carbon dioxide) and NOx (oxides of nitrogen) emissions. In terms of unregulated emissions, CEME blends in DIESEL showed lowered toluene and acetaldehyde emissions. However, acetone and formaldehyde emissions increased with higher percentage of CEME in DIESEL blend. At full load, the attained cylinder pressure and heat release rate of CEME were comparatively lower than DIESEL fuel. Overall, it can be concluded that B20 (20% CEME +80% DIESEL fuel) blend can be a positive variant feedstock and it can be utilized in an unmodified diesel engine with minimal tailpipe emissions.

Effect of acetone-butanol-ethanol (ABE)–gasoline blends on regulated and unregulated emissions in spark-ignition engine

An experimental study was conducted in a port-fuel injection (PFI) spark-ignition (SI) engine fueled with acetone-butanol-ethanol (ABE) and gasoline. 30 vol% ABE blends with different component ratios (A:B:E = 3:6:1, 6:3:1, and 5:14:1), referred to as ABE(3:6:1)30, ABE(6:3:1)30, and ABE(5:14:1)30, were used as test fuels. Additionally, 30 vol% ethanol and 30% vol.% butanol blended with 70 vol% gasoline, referred to as E30 and B30, respectively, were also used as test fuels. Both the regulated emissions, which include unburned hydrocarbons (UHC), carbon monoxide (CO), and nitrogen oxide (NOx), and unregulated emissions, including acetaldehyde, 1,3-butadiene, benzene, toluene, ethylbenzene, and xylene (BTEX), were investigated under various conditions. The experiments were conducted at an engine speed of 1200 rpm and at engine loads of 3, 4, 5, and 6 bar brake mean effective pressure (BMEP) under various equivalence ratios (φ = 0.83–1.25). The results indicated that ABE(6:3:1)30 had the lowest UHC and CO emissions, with ABE(3:6:1)30 having slightly higher NOx emissions. As for unregulated emissions, B30 showed the highest acetaldehyde emission and ABE(6:3:1)30 had the lowest among all the fuel blends. ABE(3:6:1)30 and ABE(6:3:1)30 showed a reduction in 1,3-butadiene emission. Regarding the BTEX emissions, an overall reduction was observed for all the fuel blends, with ABE(3:6:1)30 having shown the lowest BTEX emissions among all the test fuels. The results indicate that ABE could be used as a promising alternative fuel in SI engines, owing to the reduction in emissions.

Analysis of Unregulated Emissions from a Diesel Bus Equipped with CDPF

In this paper, it was studied on effects of CDPF (catalyzed diesel particulate filters, (DPF) on the unregulated emissions, volatile organic compounds (VOCs), particulate carbon components, particulate polycyclic aromatic hydrocarbons (PAHs) and its toxicity from the diesel bus emissions. The results show that the VOCs were reduced by 57.6% by the CDPF, the total carbon (TC) were reduced by 70.4%. The PAHs from diesel bus were reduced up to 91.1% and the CDPF showed higher reduction rate for low-ring PAHs, such as 3-ring and 4-ring PAHs, while it presented lower selective for higher ring PAHs. The CDPF can obviously reduce the toxicity equivalent of different benzene ring PAHs, and there was no obvious effect on toxicity equivalent ratio of different benzene rings of PAHs 柴油公交车加装CDPF的非常规污染物排放特征分析 *

Combustion performance and pollutant emissions analysis of a diesel engine fueled with biodiesel and its blend with 2-methylfuran

2-Methylfuran (MF) is a promising and attractive alternative fuel with its improved production technology, but MF is rarely applied into compression ignition engines. Here the impacts of fuel characteristics and loads on burning and emissions were investigated in a four-cylinder direct-injection compression ignition engine fueled with biodiesel and its mixtures with MF. The experimental conditions were load at 0.13–1.13 MPa brake mean effective pressure (BMEP) and speed at 1800 rpm. At 0.13 MPa BMEP, with the rising MF mass fraction, the largest values of heat release rate and cylinder pressure both declined, but both increased at 0.63 and 0.88 MPa BMEP. Biodiesel-MF blends were featured with shorter burning duration and longer ignition delay at medium and high loads. Both regulated and unregulated emissions were measured. Less HC and CO and more NOx were emitted, while the soot emissions were constantly low with the increasing MF mass fraction. Unregulated emissions of 1,3-butadiene, benzene and acetaldehyde decreased with the increasing MF mass fraction at both modest and high loads. With further engine loading, less benzene and acetaldehyde were emitted, while 1,3-butadiene emissions first dropped and then rose. The biodiesel blended with low mass fraction of MF outperformed pure biodiesel in terms of combustion and emissions except for BM30.

The effects of ash inside a platinum-based catalyst diesel particulate filter on particle emissions, gaseous emissions, and unregulated emissions.

Ash deposited in the DPF cannot be burnt, which will affect the service life of DPF. However, previous works focused on the effect of ash on the engine exhaust emissions are limited. Therefore, the influence of ash on the emissions was studied in this work. The particle emissions, the gaseous emissions, and the unregulated emissions (carbonyl compounds and volatile organic compounds) were measured by an AMA4000 gaseous analyzer, ELPI, HPLC, and GC-MS, respectively. Research results indicate that the filtration efficiency decreases by 0.57-4.49% for accumulation mode particle of particulate matter, while it has very little effects on the other type and the particle number in the presence of ash. For regular gaseous pollutions, ash has no influence on CO2 and NOx emission, while CO and THC increase by 68.2% and 91.0%, respectively. For unregulated emissions, overall, carbonyl compounds increase by 41-150% and the BTEX decreases by 8.6-23.6% after ash formed. The change is mainly caused by the increase in the exhaust backpressure that plays a key role.

Impact of HVO blends on modern diesel passenger cars emissions during real world operation

Regulated and unregulated emissions from two Euro 6b diesel passenger cars tested using three different blends of hydrotreated vegetable oil (HVO), fossil diesel and commercial diesel (B7) were investigated at 23 °C and −7 °C using the World harmonized Light-duty vehicle Test Procedure at the Vehicle Emission Laboratory of the European Commission Joint Research Centre Ispra, Italy. The HVO blends used were: Neat HVO (100 vol% HVO), 30 vol% HVO and 7 vol% HVO. One of the vehicles was also tested using the three HVO blends on-road following a RDE compliant route. Overall, the use of different HVO blends and diesel did not lead to fuel related trends on the emissions of the tested vehicles in the laboratory nor on-road. However, HVO-100 resulted in ∼4% lower CO2 emissions than the other fuel tested in all the studied conditions. Low ambient temperature caused an increase of the emissions of studied compounds (with the exception of NH3) with all tested blends. The experimental results showed that in many cases the observed outcomes were probably attributable to a combination of combustion effects, after-treatment effects, and their control strategy.

Computational study of intake temperature effects on mixture formation, combustion and unregulated emissions of a DISI methanol engine during cold start

Direct injection spark ignition (DISI) methanol engines have an excellent lean-burn properties but with more unregulated emissions of formaldehyde and unburned methanol and cold start difficulties. In this study, intake temperature effects on mixture formation, combustion processes, and unregulated emissions of formaldehyde and unburned methanol were numerically simulated for a stratified-charge DISI methanol engine during cold start. Computational results show that increasing the intake temperature during cold start boosts the evaporation of methanol and improves the in-cylinder distribution of methanol-air mixture, thereby accelerating the combustion and mitigating formaldehyde and unburned methanol emissions. When the intake temperature increases from 283 K to 293 K, the ignition delay is reduced by 1.3°CA (crank angle). Meanwhile, the maximum cylinder pressure, maximum heat release rate, and maximum cylinder temperature increase by approximately 0.59 MPa, 20 J/°CA and 165 K, respectively; formaldehyde and unburned methanol emissions are reduced by 27% and 48%. When the intake temperature is further increased to 313 K, the effects on the engine operations as well as emissions become weaker. There were almost no improvements on combustion or unregulated emissions when the intake temperature was above 313 K.

Comparative study on low ambient temperature regulated/unregulated emissions characteristics of idling light-duty diesel vehicles at cold start and hot restart

Since it is common for vehicles with idle engines to be stored indoors during the winter season to remain warm, better constraints are needed for idling emissions at low ambient temperature. CH4 (methane), C2H6 (ethane), C2H4 (ethylene), HNCO (isocyanic acid), N2O (nitrous oxide), NH3 (ammonia), C3H6 (propylene), and HCHO (formaldehyde) from many unregulated exhaust emissions were selected and measured by a Fourier Transform Infrared Spectroscopy (FTIR) analyzer in this study. This paper investigates the idling regulated and unregulated emissions of Euro 5/6 diesel vehicles at cold start and hot restart near 0 °C conditions. The impact of cold start and hot restart on NOx idling emissions was lower than CO and HC idling emissions in diesel vehicles. With regard to unregulated emissions, high fuel–air equivalence ratios and longer ignition delay in the idle cold start condition may increase incomplete combustion and affect the thermal cranking processes, leading to the increase of CH4, C2H4 and C3H6. Furthermore, as the formation of N2O is considerably affected by the equivalence ratio and cylinder temperature, a high fuel-air equivalence ratio at low ambient temperature in the cold start condition resulted in the increase of N2O emissions.

Experimental study on the durability of biodiesel-powered engine equipped with a diesel oxidation catalyst and a selective catalytic reduction system

This study aims to investigate the effect of durability on the regulated and unregulated emissions, as well as the power and fuel economy performance of a biodiesel-powered engine equipped with a diesel oxidation catalyst (DOC) and a selective catalytic reduction (SCR) system based on a 500-h durability test. Furthermore, a BET (Brunauer-Emmett-Teller) test was employed to analyze the specific surface area changes of the DOC and SCR. Results show that after the durability, the power performance improved and the brake-specific fuel consumption (BSFC) reduced due to the running-in effect. Although the deterioration of the DOC and SCR after the durability resulted in an increase in the carbon monoxide (CO), total hydrocarbon (THC) and nitrogen oxide (NOX) emission factors of the biodiesel-powered engine based on European steady state cycle (ESC) by 41.3%, 36.1% and 39.2%, respectively, these emissions were still below China-Ⅴ limits. For unregulated emissions, the reduced BSFC caused by the durability led to a decrease in the carbon dioxide (CO2) and sulfur dioxide (SO2) emissions, but the durability resulted in higher aldehyde emission. The BET specific surface areas of the DOC and SCR decreased by 40.2% and 35.0%, respectively after the durability, which accounted for their catalytic performance deterioration.

Experimental studies on the co-effects of engine operating parameters and fuel functional groups on the performance and emissions of a GDI engine

The distributions of molecular functional groups in gasoline have strong effects on the in-cylinder micro-combustion, macro-heat release and emission generation mechanism. It is quite difficult to study the coupling relationship between fuel functional groups and engine performance with commercial gasoline due to its complex components. In this paper, multi-components gasoline surrogates including toluene reference fuel (TRF), n-heptane/iso-octane/toluene/cyclohexane (CTRF) and n-heptane/iso-octane/toluene/cyclohexane/diisobutylene (CDTRF) were applied to study the effects of fuel functional groups and engine control parameters (spark timing, equivalence ratio) on combustion and emissions of a gasoline direct injection (GDI) engine. Amongst the results, it is worth noting that the surrogates produce 30–40% higher nitrogen oxide (NOx) emissions than gasoline and have obvious advantages in particulate matter (PM) emissions, however, at the cost of high carbon monoxide (CO) and total hydrocarbon (THC) emissions. In addition, there are obvious differences in combustion characteristics and unregulated emissions between the surrogates due to different functional groups.

Performance and Regulated/Unregulated Emission Evaluation of a Spark Ignition Engine Fueled with Acetone–Butanol–Ethanol and Gasoline Blends

An experimental investigation was conducted on the effect of equivalence ratios and engine loads on performance and emission characteristics using acetone–butanol–ethanol (ABE) and gasoline blends. Gasoline blends with various ABE content (0 vol % to 80 vol % ABE, referred to as G100, ABE10, ABE20, ABE30, ABE60, and ABE80, respectively) were used as test fuels, where the volumetric concentration of A/B/E was 3:6:1. The experiments were conducted at engine loads of 3, 4, 5, and 6 bar brake mean effective pressure at an engine speed of 1200 rpm and under various equivalence ratios (φ = 0.83–1.25). The results showed that ABE addition in the fuel blends could increase brake thermal efficiency and decrease unburned hydrocarbon (UHC), carbon dioxide (CO), and oxynitride (NOx). As for unregulated emissions, acetaldehyde and 1,3-budatiene emissions increased with the increased ABE content in blend fuels. Regarding the aromatic emissions, ABE addition led to a decrease in benzene, toluene, and xylene emissions. The study indicated that ABE could be used as a promising alternative fuel in spark ignition (SI) engines for enhancing the brake thermal efficiency and reducing regulated emissions and aromatic air toxics.

Combustion Mode Switching Characteristics of a Medium-Duty Engine Operated in Compression Ignition/PCCI Combustion Modes

Premixed charge compression ignition (PCCI) combustion is a novel combustion concept, which reduces oxides of nitrogen (NOx) and particulate matter (PM) emissions simultaneously. However, PCCI combustion cannot be implemented in commercial engines due to its handicap in operating at high engine loads. This study is focused on the development of hybrid combustion engine in which engine can be operated in both combustion modes, namely, PCCI and compression ignition (CI). Up to medium loads, engine was operated in PCCI combustion and at higher loads, the engine control unit (ECU) automatically switched the engine operation to CI combustion mode. These combustion modes can be automatically switched by varying the fuel injection parameters and exhaust gas recirculation (EGR) by an open ECU. The experiments were carried out at constant engine speed (1500 rpm) and the load was varied from idling to full load (5.5 bar brake mean effective pressure (BMEP)). To investigate the emission and particulate characteristics during different combustion modes and mode switching, continuous sampling of the exhaust gas was done for a 300 s cycle, which was specifically designed for this study. Results showed that PCCI combustion resulted in significantly lower NOx and PM emissions compared to the CI combustion. Lower exhaust gas temperature (EGT) in the PCCI combustion mode resulted in slightly inferior engine performance. Slightly higher concentration of unregulated emission species such as sulfur dioxide (SO2) and formaldehyde (HCHO) in PCCI combustion mode was another important observation from this study. Lower concentration of aromatic compounds in PCCI combustion compared to CI combustion reflected relatively lower toxicity of the exhaust gas. Particulate number-size distribution showed that most particulates emitted in PCCI combustion mode were in the accumulation mode particle (AMP) size range, however, CI combustion emitted relatively smaller sized particles, which were more harmful to the human health. Overall, this study indicated that mode switching has significant potential for application of PCCI combustion mode in production grade engines for automotive sector, which would result in relatively cleaner engine exhaust compared to CI combustion mode engines.

Performance evaluation of a biodiesel fuelled transportation engine retrofitted with a non-noble metal catalysed diesel oxidation catalyst for controlling unregulated emissions

In present study, engine exhaust was sampled for measurement and analysis of unregulated emissions from a four cylinder transportation diesel engine using a state-of-the-art FTIR (Fourier transform infrared spectroscopy) emission analyzer. Test fuels used were Karanja biodiesel blend (B20) and baseline mineral diesel. Real-time emission measurements were performed for raw exhaust as well as exhaust sampled downstream of the two in-house prepared non-noble metal based diesel oxidation catalysts (DOCs) and a baseline commercial DOC based on noble metals. Two prepared non-noble metal based DOCs were based on Co-Ce mixed oxide and Lanthanum based perovskite catalysts. Perovskite based DOC performed superior compared to Co-Ce mixed oxide catalyst based DOC. Commercial noble metal based DOC was found to be the most effective in reducing unregulated hydrocarbon emissions in the engine exhaust, followed by the two in-house prepared non-noble metal based DOCs.