Reference Diesel Research Articles

Intelligent charge compression ignition combustion for range extender medium duty applications

Electrified powertrains have been growth in the last few years due to the increase in powertrain efficiency. However, for heavy-duty vehicles the right choice it is not clear. The long-routes and large number of daily kilometres makes that current battery technology it is not prepared to cover the minimum requirements. A mid-term solution is hybrid powertrains. The mix between pure electric range and range extender mode in liquid fuels make perfect to complete a large distance. However, tailpipe pollutant and CO2 emissions are still a disadvantage against pure electric powertrain. This study analyses the potential of hybrid powertrains running in an advanced combustion mode as Intelligent Charge Compression Ignition. Due to the flexibility of the combustion mode different renewable energy fuels are tested: Butanol, Methanol and Biodiesel. The work is focused in urban buses due to the potential of electrified powertrains in this context and the large number of vehicles concentrated in cities. The results show that pure electric bus reduce 54% the CO2 emissions at LCA level. Meanwhile the Intelligent Charge Compression Ignition allows to 32% with one renewable fuel (Diesel-Butanol) and 66% with two renewable fuels (Biodiesel-Methanol) with respect to the non-hybrid diesel reference.

Effect of diesel detergent synergists on VOCs emissions from engine

In this study, the volatile organic compounds (VOCs) emissions from engine fueled diesel with and without detergent synergist were measured by gas chromatography mass spectrometry(GC-MS). The test results show that compared with reference diesel fuel (without diesel detergent synergist), the use of different diesel detergent synergists has different effects on the VOCs emissions while without after-treatment device. Whether with or without after-treatment device, alkanes always account for the highest proportion of VOCs emissions while engine fuels with different diesel detergent synergists. After-treatment device diesel oxidation catalyst coupled with diesel particulate filter (DOC+DPF) has high catalytic efficiency for VOCs emissions from engine fueled with different fuels, and most of the catalytic efficiency could reach more than 95%. With the catalytic treatment of after-treatment device,the concentrations of carcinogens (detected in this study) in VOCs emissions from engine fueled with and without detergent synergist are far lower than that specified in reference standard GBZ 2.1-2007 “Occupational Exposure Limits for Hazardous Factors in the Workplace and Chemical Hazardous Factors”, respectively. The test results indicate that the use of diesel detergent synergist will not have an adverse impact on human health and it can be safely used.

Retracted] Analysis of Environmental Emission Neat Diesel‐Biodiesel–Algae Oil‐Nanometal Additives in Compression Ignition Engines

The production of biodiesel as an alternative fuel and its use as a mixture and other additives are presented. In the present research work, additive blends with diesel biodiesel from algae oil are physically characterised and an analysis of pollutant emissions is carried out when used in an ignition engine by compression. The measurement of pollutant emissions is carried out through a combined emission analyzer adapted to a system of valves attached to the experimental facility. The properties of each mixture with the polluting emissions are compared with that of the reference diesel. It was found that each of the properties improves compared to that of diesel, reducing most emissions in the use of mixtures with biodiesel.

Ammonia-based Solid Oxide Fuel Cell for zero emission maritime power: a case study

Implementing environmentally friendly fuels and high efficiency propulsion technologies to replace the Internal Combustion Engine (ICE) fueled by fossil fuels such as Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO) on board ships represents an attractive solution for maritime power. In this context, fuel cells can play a crucial role, thanks to their high energy efficiency and ultra-low to zero criteria pollutant emissions and environmental impact. This paper performs the technical feasibility analysis for replacing the conventional diesel engine powertrain on board a commercial vessel with an innovative system consisting of ammonia-fuel-based Solid Oxide Fuel Cell (SOFC) technology. Taking into account the size of the diesel engines installed on board and the typical cruise performed by the commercial vessel, the ammonia consumption, as well as the optimal size of the innovative propulsion system have been assessed. In particular, the SOFC powertrain is sized at the same maximum power output as the main reference diesel engine. The mass and energy balances of the ammonia-based SOFC system have been performed in Aspen PlusTM environment. The gravimetric (kWh kg−1) and volumetric (kWh m−3) energy density features of the ammonia storage technology as well as the weight and volume of the proposed propulsion system are evaluated for verifying the compliance with the ship’s weight and space requirements. Results highlight that the proposed propulsion system involves an increase in weight both in the engine room and in the fuel room compared to the diesel engine and fuel. In particular, a cargo reduction of about 2.88% is necessary to fit the ammonia-based SOFC system compared to the space available in the reference diesel-fueled ship.

Waste to Energy: An experimental comparison of burning the waste-derived bio-oils produced by transesterification and pyrolysis methods

In the present research, waste cooking oil biodiesel (WB) and waste pyrolysis oil (WPO) are produced via transesterification and pyrolysis methods. Then the produced WB and WPO are blended at the volumetric percentages of 25, 50, 75, and 100% into the conventional diesel fuel. These fuel blends are tested on a single-cylinder diesel engine under the varying engine loads (1, 2, 3, and 4 kW) at a constant crankshaft speed of 1500 rpm. The results show that both WB and WPO blended fuels decrease the brake thermal efficiency and higher exhaust gas temperature than diesel fuel. As the WB content in the test fuel increases, CO, HC, and smoke emissions gradually decrease due to the high oxygen content of WCO, but NOx emission increases. In terms of exhaust emissions, the reverse trend is noticed for WB blended test fuels (high CO, HC, and smoke, but low NOx) with the lack of oxygen atoms for WPO substitutes. As the percentage of WPO in the test fuel is increased, CO, HC, and smoke emissions gradually increase in comparison to those of diesel fuel, while NOx emissions exhibited a reverse trend. In comparison to that of reference diesel fuel, the highest thermal efficiency declines are found to be 22% for WB100 and 19% for WPO100. WPO100 leads to the significant increment in the HC, CO, and smoke emissions by 59, 36, and 31%, respectively. Compared to diesel fuel, WB100 ensures the highest CO, HC, and smoke emission reduction by 45, 62, and 47%, respectively. On the other hand, the maximum increase in NOx emission is found to be 46% for WB100 test fuel, while the maximum decrease is found to be 25% for WPO100 test fuel as compared to that of diesel fuel. In terms of engine performance and exhaust pollutants excluding NOx emission, it is well-noticed that the WB substitutes present more promising results than those of WPO substitutes. Accordingly, the present research proves that the transesterification method is more suitable for biofuel production than the pyrolysis method.

Дослідження змащувальної здатності дизельного та авіаційного палива на паливному насосі високого тиску

This paper presents comparative experimental study’s results of diesel fuel and aviation fuel effect on operational properties of a high-pressure fuel pump of a common rail injection system. The two identical fuel injection systems mounted on a test bed of the fuel injection pumps were prepared for the experimental durability tests. The lubricity properties of diesel fuel and aviation fuel (Jet-A1) were studied using the High-Frequency Reciprocating Rig (HFRR) method. The values of wear scar diameter (WSD) obtained with Jet-A1 fuels were compared to the respective values measured with the reference diesel fuel. The microscopic photographs of the wear scar diameters obtained on above mentioned fuels are presented in the paper. The test results showed that long-term (about 300 hours) using aviation fuels produced a negative effect on the durability of the high-pressure fuel pump. Due to the wear of plunger-barrel units the decrease in the fuel delivery rate occurred of about 6.7 % operating with aviation fuel. The average friction coefficients of Jet-A1 fuels were higher than that of the normal diesel fuel.
 Keywords: diesel fuel, aviation Jet-A1 fuel, lubricity, plunger-barrel units, wear scar diameter

Numerical investigation of glycerol/diesel emulsion combustion in compression ignition conditions using Stochastic Reactor Model

In this work, we numerically investigate the potential of glycerol as a diesel fuel additive to reduce soot emissions. Many different fuel additives offer environmental benefits, since there is a surplus supply of glycerol as a by-product of biodiesel production, it is considered as a promising available candidate. The combustion process of glycerol in a direct injection compression ignition engine has been previously investigated experimentally for a 10 % (vol) glycerol emulsion. Based on the experimental set-up, a zero-dimensional Stochastic Reactor Model (SRM) is constructed to conduct numerical analysis with a detailed chemical mechanism for the combustion of hydrocarbon and oxygenated fuels. Applied models are presented and discussed with a focus on the characteristic mixing time scale of micromixing closure which is calculated using a 0D k-ε. The model constants are optimized to the analysed engine with the aid of a genetic algorithm and the sensitivity analysis is presented. For both fuels, emissions of major species are reproduced well but NOx results are slightly overestimated. Emissions of carbon monoxide are predicted well for the reference diesel fuel, but the SRM does not capture the trend of increased CO with glycerol emulsion. The stochastic nature of the model is used to represent the mixture inhomogeneity, and the results are analysed using equivalence ratio–temperature plots to identify soot promoting conditions. The evolution of selected soot precursor and oxidizers is analysed, showing the capability of glycerol to reduce the former and increase the latter with a moderate effect. Soot formation and decomposition rates are presented, with very similar behaviour for both fuels. A shorter combustion phasing for the glycerol emulsion was observed and identified as the main contributory factor that led to the soot reduction while the chemical effect i.e oxygen content of the glycerol was present but not the dominant factor. The soot model results do not provide any evidence for the origin of experimentally observed small-sized particles, but it is discussed that the emissions results indicate the presence of low volatile compounds that could condense in the exhaust system.

Fuel property improvement and exhaust emission reduction, including noise emissions, using an oxygenated additive to waste plastic oil in a diesel engine

AbstractThis work reports on an extensive investigation of the physicochemical properties, engine performance, exhaust emissions, and fundamental energy and exergy parameters of waste‐plastic oils blended with an additive, diethyl ether and diesel. A four‐stroke single‐cylinder diesel engine was used for the engine experiments. The seven fuels in this study include a neat diesel, a neat waste plastic oil, two binary blends of diesel‐waste plastic oil, and three ternary blends of diesel with waste plastic oil and diethyl ether. The justification for selecting diethyl ether was to augment fuel properties in the blend and to further reduce emissions. The reasons for choosing waste plastic are not only to harness energy from waste plastic but also to offer an effective solution to the plastic waste management issue. The choice of diesel was to use it as a reference fuel for comparison with other fuels. Fuel properties were observed to be similar, and in some cases better, with the blends. Notable reductions in emissions with identical engine performance and energy and exergy parameters were observed with the five oxygenated blends (plastic oil blends) than with a reference diesel fuel. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Advanced optimal planning for microgrid technologies including hydrogen and mobility at a real microgrid testbed

This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis, seasonal storage and fueling station for meeting the hydrogen fuel demand of fuel cell vehicles, busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation).

Yeni bir biyodizel kaynağı olarak uçucu yağların dizel motorlarda kullanılabilirliğinin araştırılması

This article has focused on essential oils as alternative fuels and fuel additives. The essential oil is obtained from Salvia Candidissima plant. While a Clevenger type apparatus was used to determine the oil yield of Salvia Candidissima plant, a retort was produced for the bulk oil to be used in the experiments. The compounds of the obtained oil were determined by Gas chromatography / Mass spectrometry (GC / MS) and the essential oil was converted into biofuel. The produced biofuel was added 5% by volume to the reference diesel fuel (DF) and mixed fuel (SB-5) was formed. Later, SB-5 and DF fuels were tested at 1500 fixed cycles and different loads, and emission and combustion data were obtained. As a result of the experiment, effective decreases in Carbon Monoxide (CO) and Hydrocarbon (HC) emissions and increases in NOx emissions were observed with SB-5 fuel mixture. In addition, higher combustion data were obtained with SB-5 fuel mixture than DF fuel.

Particle Size Distribution Measurements of Neat and Water-Emulsified Oxymethylene Ethers in a Heavy-Duty Diesel Engine

Diesel-fueled compression ignition engines display a distinct trade-off in particulate matter (PM) and nitrogen oxide (NOX) emissions due to the nature of diffusive combustion. The modification of fuel properties has drawn much attention since these methods offer additional potential to reduce emissions. Oxygenated fuels are reported to greatly diminish particle emissions while water emulsification of regular diesel causes a significant decrease in NOX. However, recent studies indicate that these fuel-based approaches may lead to an increase in nanoparticle emissions, which are known to be more dangerous to human health than large particles. This has raised the question about whether current engine technology is prone to nanoparticle formation.In this work, the authors present a detailed study on combustion and emission performance of the oxygenate fuel Oxymethylene Ether (OMEn, the mixture contains neat OME with chain length n = 2 − 6). In a novel approach, a single-cylinder heavy-duty diesel engine was fueled with both neat and water-emulsified OME to combine the two fuel-based methods in order to simultaneously reduce both NOX and particle emissions to a great extent. Particular emphasis was put on the particle size distribution (PSD) of emitted PM to elaborate a potentially severe drawback of these fuel-based approaches. In the process, hydrogenated vegetable oil (HVO) was used as the diesel reference fuel. The findings are summarized as such: PSD measurements of OME2-6 reveal similar particle diameters in mid-load operation and a shift to smaller particles at unfavorable engine operations compared to HVO. Water-emulsified OME2-6 reduces NOX by roughly 2-3% with a one percent increase in water concentration while maintaining a nearly constant combustion efficiency. Adverse effects on nanoparticle formation by water emulsification were not observed.

Particle characterization and toxicity in C57BL/6 mice following instillation of five different diesel exhaust particles designed to differ in physicochemical properties

BackgroundDiesel exhaust is carcinogenic and exposure to diesel particles cause health effects. We investigated the toxicity of diesel exhaust particles designed to have varying physicochemical properties in order to attribute health effects to specific particle characteristics. Particles from three fuel types were compared at 13% engine intake O2 concentration: MK1 ultra low sulfur diesel (DEP13) and the two renewable diesel fuels hydrotreated vegetable oil (HVO13) and rapeseed methyl ester (RME13). Additionally, diesel particles from MK1 ultra low sulfur diesel were generated at 9.7% (DEP9.7) and 17% (DEP17) intake O2 concentration. We evaluated physicochemical properties and histopathological, inflammatory and genotoxic responses on day 1, 28, and 90 after single intratracheal instillation in mice compared to reference diesel particles and carbon black.ResultsModerate variations were seen in physical properties for the five particles: primary particle diameter: 15–22 nm, specific surface area: 152–222 m2/g, and count median mobility diameter: 55–103 nm. Larger differences were found in chemical composition: organic carbon/total carbon ratio (0.12–0.60), polycyclic aromatic hydrocarbon content (1–27 μg/mg) and acid-extractable metal content (0.9–16 μg/mg). Intratracheal exposure to all five particles induced similar toxicological responses, with different potency. Lung particle retention was observed in DEP13 and HVO13 exposed mice on day 28 post-exposure, with less retention for the other fuel types. RME exposure induced limited response whereas the remaining particles induced dose-dependent inflammation and acute phase response on day 1. DEP13 induced acute phase response on day 28 and inflammation on day 90. DNA strand break levels were not increased as compared to vehicle, but were increased in lung and liver compared to blank filter extraction control. Neutrophil influx on day 1 correlated best with estimated deposited surface area, but also with elemental carbon, organic carbon and PAHs. DNA strand break levels in lung on day 28 and in liver on day 90 correlated with acellular particle-induced ROS.ConclusionsWe studied diesel exhaust particles designed to differ in physicochemical properties. Our study highlights specific surface area, elemental carbon content, PAHs and ROS-generating potential as physicochemical predictors of diesel particle toxicity.

Comparative study on gene expression profile in rat lung after repeated exposure to diesel and biodiesel exhausts upstream and downstream of a particle filter

Biodiesel is considered as a valuable and less toxic alternative to diesel. However, cellular and molecular effects of repeated exposure to biodiesel emissions from a recent engine equipped with a diesel particle filter (DPF) remain to be characterized. To gain insights about this point, the lung transcriptional signatures were analyzed for rats (n = 6 per group) exposed to filtered air, 30% rapeseed biodiesel (B30) blend or reference diesel (RF0), upstream and downstream a DPF, for 3 weeks (3 h/day, 5 days/week).Genomic analysis revealed a modest regulation of gene expression level (lower than a 2-fold) by both fuels and a higher number of genes regulated downstream the DPF than upstream, in response to either RF0 or to B30 exhaust emissions. The presence of DPF was found to notably impact the lung gene signature of rats exposed to B30. The number of genes regulated in common by both fuels was low, which is likely due to differences in concentrations of regulated pollutants in exhausts, notably for compound organic volatiles, polycyclic aromatic hydrocarbons, NO or NOx. Nevertheless, we have identified some pathways that were activated for both exhaust emissions, such as integrin-, IGF-1- and Rac-signaling pathways, likely reflecting the effects of gas phase products. By contrast, some canonical pathways relative to “oxidative phosphorylation” and “mitochondrial dysfunction” appear as specific to B30 exhaust emission; the repression of transcripts of mitochondrial respiratory chain in lung of rats exposed to B30 downstream of DPF supports the perturbation of mitochondria function.This study done with a recent diesel engine (compliant with the European IV emission standard) and commercially-available fuels reveals that the diesel blend composition and the presence of an after treatment system may modify lung gene signature of rats repeatedly exposed to exhaust emissions, however in a rather modest manner.

The Effects of Different Higher Alcohols (1-Butanol, 1-Pentanol, 1-Hexanol) Addition into the Diesel Fuel on the Performance, Combustion, and Exhaust Emission Characteristics of a Single-Cylinder Diesel Engine

The reduction of petroleum reserves day by day all over the world depending on the increase in petroleum consumption and the reaching serious levels of environmental pollution have led researchers to search alternative and clean energy sources for internal combustion engines. The higher alcohols having four or more carbon atoms in their chemical structure come to the fore for diesel engines due to the negative properties of short-chain alcohols (methanol and ethanol) such as low energy content and cetane number. The aim of this study is to compare the performance, emissions, and combustion characteristics of a single-cylinder, four-stroke, direct injection diesel engine operating with alternative fuels which contains 15% by volume of 1-butanol, 1-pentanol and 1-hexanol alcohols (Bt15: 15% 1-butanol + 85% diesel fuel, Pt15: 15% 1- pentanol + 85% diesel fuel, Hx15: 15% 1-hexanol + 85% diesel fuel) with reference diesel fuel (D100) by testing at a fixed engine speed of 1500 rpm and different loads (25%, 50%, 75%, and 100%). As a result, it is noticed to be that alcohol-infused fuel blends caused to decrease the brake thermal efficiency and increase brake specific fuel consumption due to the lesser calorific values of the alcohols according to the diesel fuel. At 100% engine load, the maximum cylinder pressures were observed as 46.97 bar, 47.76 bar, 48.41 bar, and 48.91 bar, respectively while the peak net heat release rates of D100, Bt15, Pt15, and Hx15 were found to be at 29.55 J/o, 31.14 J/o, 32.66 J/o, and 33.80 J/o, respectively. Besides, it is determined that the ignition delay period of the alcohol-treated fuel blends is generally extended as compared to the diesel fuel because of the lower cetane number of alcohol. CO2 and O2 emissions increased with the addition of alcohol to diesel fuel while CO, HC and NOX emissions as well as exhaust gas temperatures reduced. When all experimental results were evaluated, it could be noted that the Hx15 blend gave the best results in terms of performance, emissions and combustion properties.

Investigation of Dual-Fuel Combustion by Different Port Injection Fuels (Neat Ethanol and E85) in a DE95 Diesel/Ethanol Blend Fueled Compression Ignition Engine

Abstract This paper investigated the effect of different substitution ratios of neat ethanol (E100) and ethanol–gasoline blend E85 on in-cylinder combustion, engine efficiency, and exhaust emissions, in a dual-fuel diesel engine, using the ethanol–diesel blend (DE95). Experimental studies realized at 1400 rpm, 1600 rpm, and 1800 rpm engine speeds under constant engine load of 50% (20 Nm). For each engine speed, the injection timing of diesel and E95 fuels at 24 °CA bTDC kept constant while low-reactivity fuels (i.e., E100 and E85) substitution ratio changed in the range of 59–83%. The results showed that premixed fuels in different SRs have an impact on shaping engine emissions, ignition delay (ID), in-cylinder pressure, and heat-release rate. Also, at the dual-fuel experimental studies in all engine speeds, NOx about 47–67% decrease compared to single fuel conditions of reference diesel and DE95, and smoke opacity remained unchanged around 0.1 FSN, whereas HC and CO increased in the range of 20–50%. However, E85/DE95 and E100/DE95 dual-fuel combustion achieved lower brake thermal efficiency (BTE) and combustion efficiency compared to single diesel fuel combustion. On the other hand, in dual-fuel combustion conditions, despite the low combustion efficiency, premixed E85 fuel offered higher engine efficiency and lower exhaust emissions than E100.

Performance and regulated gaseous emissions of a Euro 6 diesel vehicle with Lean NOx Trap at different ambient conditions: Sensitivity to the type of fuel

Three advanced biofuels, namely HVO (Hydrotreated Vegetable Oil), a glycerol-derived biofuel (Mo·bio) and biodiesel from oil industry wastes, were tested in a Euro 6 diesel vehicle equipped with a Lean NOx Trap under the worldwide harmonized light-duty vehicles test cycle (WLTC) at warm (24 °C) and cold (−7 °C) ambient temperature. HVO was tested pure, biodiesel was used both pure and blended at 20% (v/v) with a reference diesel fuel and Mo·bio was also blended with the diesel fuel at the same ratio. In order to analyse the sensitivity of the gaseous emissions and the aftertreatment efficiency to the type of fuel, emissions were measured upstream and downstream of the aftertreatment system and fuel-associated effects were isolated from those of the engine operating conditions (EGR rate, injection strategy and equivalence ratio). The energy consumption was not very different between fuels, although HVO led to a higher engine efficiency while biodiesel behaved oppositely at the low speed phase. Regarding NOx emissions, no differences were found between fuels while cold temperature led to higher NOx because of the lower EGR rate and the use of only high pressure EGR. Biodiesel and Mo·bio improved CO and THC engine-out emissions at warm temperature, but these compounds were deteriorated at low ambient conditions because of the poorer viscosity and volatility of these fuels. The DOC efficiency was higher for CO than for THC excepting the low speed phase, for which deposition of high molecular weight hydrocarbons could mask the results. The LNT efficiency was lower at cold conditions because of the high NOx engine-out emissions. Differences between fuels were only observed in the case of the DOC and during the engine warm-up period.

THOROUGH ANALYSIS OF COMBUSTION AND EMISSIONS OF POWER GENERATOR DIESEL ENGINE AT HIGH IDLING OPERATIONS FUELED WITH LOW PERCENTAGE OF DIFFERENT BIODIESEL BLENDS

In this study, the ultimate aim is to provide objective scientific proof to promote biodiesel blends in constant areas (official institutions, hospital, school,) as a renewable fuel. For that, biodiesel obtained from animal, vegetable and microalgae oil by a method of transesterification and these biodiesels have been prepared by 10% blended with diesel fuel and has been named respectively as AB10, VB10 and MB10. The biodiesel blends have been compared with reference diesel fuel (ULSD) by taking combustion values in a diesel engine generator system under cold start, loadless and constant engine speed of 1500 rpm. Experimental results showed that using biodiesel blends in diesel engine had almost parallel cylinder gas pressure (CGP), cumulative heat release (CHR), heat release rate (HRR), knock density and mean gas temperature (MGT) compared to ULSD fuel operation in research diesel engine. In addition, CO, NOx and HC emissions decreased, CO2 increased compared to ULSD fuel at same experimental conditions.

Experimental studies on biodiesel production from leather industry waste fat and its effect on diesel engine characteristics

In this study, biodiesel was produced from the leather industry waste fat (LWFB), which is harmful to the environment and paid for its disposal. The methyl ester yield of the produced biodiesel was found to be 86.8%. LWFB was mixed with petroleum diesel fuel at 10% and 30% ratios and was named LWFB10 and LWFB30, respectively. The impacts of LWFB blends on a single cylinder four stroke cycle direct injection diesel engine operating characteristics were analyzed under different engine loads and speeds. The results showed that the LWFB blends began to be injected earlier than petroleum-based diesel fuel. The ignition delay was almost the same for all test fuels since the cetane number of LWFB is the same as the reference diesel fuel. The combustion duration of LWFB blends were shorter at all engine loads and speeds than diesel fuel. The peak values of cylinder pressure and heat release rate of LWFB blends were almost the same as the diesel fuel. It was noticed that the brake specific fuel consumption values of LWFB blends were higher than the reference diesel fuel at all engine loads and speeds and brake thermal efficiency was inversely proportional to brake specific fuel consumption as expected. It was also found that LWFB blends reduced smoke emissions but did not cause a significant change in NOx emissions.

An experimental study of a very high-pressure diesel injector (up to 5000 bar) by means of optical diagnostics

The aim of this work is to investigate a novel very high-pressure diesel injector under different working conditions. Furthermore, the aim of this work is also to analyse the behaviour of the evaporation, mixing and combustion of a diesel spray in a quiescent environment at very high injection pressures. In order to achieve this, the injector was first characterized from 2500 bar to 4000 bar of injection pressure. Then, an experimental matrix was designed to study the high-pressure spray under (i) cold non-evaporating, (ii) evaporating non-reactive and (iii) reactive conditions under different injection pressures up to 5000 bar. The experiments were carried out in a constant volume cell equipped with optical accesses. This allowed the application of the schlieren, mie-scattering and OH* chemiluminescence techniques at high speed to quantify the propagation of the spray through the ambient gases. The injector used was a prototype single-hole axial injector working with reference diesel as the injection fluid. The results showed a strong dependency of the spray tip penetration on the injection pressure. In some conditions creating shock waves inside the chamber that would disrupt the spray flow, causing it to mix better. Although the higher exit velocities made the fuel travel faster, resulting in longer penetrations of both phases, it also caused the fuel to evaporate faster due to slightly better mixing, resulting in similar liquid length values. This increased momentum enhanced mixing, resulting also in shorter ignition delay times. The higher velocities caused the flame base to stabilise further from the nozzle, which led to longer lift-off lengths.

Impact of various metal-oxide based nanoparticles and biodiesel blends on the combustion, performance, emission, vibration and noise characteristics of a CI engine

With the burning of 1 L of diesel fuel, approximately 3 kg of greenhouse gas is released into the atmosphere. Therefore, it is of great importance to reduce emissions with some additives in diesel engines. This study deals with the impacts of blends of waste cooking oil methyl ester and various metal-oxide based nanoparticles on the emission, combustion, performance, vibration and noise characteristics of a single-cylinder diesel engine. The test engine was loaded at different engine loads of 2.5, 5, 7.5 and 10 Nm and a constant engine speed of 2000 rpm. In this investigation, various fuels [called as reference diesel (D100), 10 vol% of waste cooking oil methyl ester (B10), and finally the mass fractions of 100 ppm aluminium oxide (B10Al2O3), titanium oxide (B10TiO2) and silicon oxide (B10SiO2) into the B10, separately] were tested. The addition of metal-oxide based nanoparticles has firstly increased the viscosity, cetane number, and heating value of biodiesel. Higher oxygen atoms in biodiesel-nanoparticles blends have improved the quality of the combustion process. Higher peak point in CPmax and HRRmax could be reached in these nano fuels due to their lower cetane numbers than that of D100. CO, HC and NOx emissions were significantly reduced with the blending of nanoparticles and biodiesel in comparison with those of D100. The addition of nanoparticles highly improved engine performance. B10 had the lowest thermal efficiency due to its heating value, but its efficiency was converted to the highest one with the addition of nanoparticle. In conclusion, this study is suggesting that the addition of metal-oxide based nanoparticles into biodiesel blends can give better results than using biodiesel alone for diesel engines.