Diesel Combustion Research Articles

A CFD Study on the Effects of Injection Timing and Spray Inclusion Angle on Performance and Emission Characteristics of a DI Diesel Engine Operating in Diffusion-Controlled and PCCI Modes of Combustion

In three-dimensional (3D) computational fluid dynamics (CFD) simulations, the effects of injection timing and spray inclusion angle (SIA) on performance and emissions of diffusion-controlled and Premixed Charge Compression Ignition (PCCI) combustion in part load for a heavy-duty direct injection (HDDI) diesel engine are studied. The start of injection (SOI) of a 146° SIA injector is varied between −70 and −10 °crank angle (°CA) after top dead center (ATDC). For −50 °CA ATDC SOI with various SIAs between 80° and 146°, PCCI combustion reduces mono-nitrogen oxide (NOx) emissions significantly compared to conventional diesel combustion (CDC). Due to incomplete combustion in rich zones formed by droplet–cylinder wall interaction, early wide SIA injection deteriorates combustion efficiency (CE) and Indicated Mean Effective Pressure (IMEP) and increases soot and carbon monoxide (CO) emissions. Narrow-angle sprays interacting with the piston bowl elevate CE and IMEP and decrease soot and CO emissions but increases NOx emissions. Optimal combustion is achieved by avoiding fuel droplet–cylinder wall interaction. By spray-targeting at the stepped lip of the piston bowl, 100° SIA and −50 °CA ATDC SOI yield, respectively, the highest CE and IMEP: 97.8% and 3.37 bar and the lowest soot and CO emissions: 33.5 and 2.2 ppm, with acceptable NOx emissions.

Parametric optimization with Biodiesel-water emulsion under premixed lean combustion to achieve high efficiency and clean combustion

Advanced low temperature combustion (LTC) aids in simultaneously controlling exhaust emissions of oxides of nitrogen (NOx) and particulate matter (PM). However, LTC strategies are constrained by achievable load range restriction and higher levels of unburned hydrocarbon (HC) and carbon monoxide (CO). The present investigation envisages combining renewable biodiesel-water emulsions and an advanced premixed lean combustion strategy to curtail the higher HC and CO emissions without sacrificing engine performance. Non-edible Karanja oil was the source of biodiesel and the emulsion stabilizer. A production light-duty diesel engine is modified to run under premixed lean combustion conditions based on late injection using a fully-flexible electronic fuel injection system. The engine operating parameters were optimized, including fuel injection timing, EGR flow rate, and emulsion water concentration. Emulsions of neat biodiesel were prepared to contain 6, 12, and 18% water on a mass basis using 1 and 2% surfactant by mass. The fuel injection timing was varied from 2 to 4 degrees after the top dead centre, and up to 15% EGR flow rate was utilized. Design of experiments aided in minimizing the number of engine tests. The performance and emission parameters were the output responses. Taguchi Grey Relational Analysis established the optimal combination of input factors to improve engine performance and reduce exhaust emissions. Engine experiments at optimized operating conditions revealed that compared to conventional diesel combustion, the brake thermal efficiency and brake specific fuel consumption improved by 33 and 16%, respectively, at 5.08 bar BMEP. The NOx, smoke and HC emissions were reduced by 68, 73 and 46%, while CO emissions increased nearly two-fold.

Effects of aluminum and copper oxides nanoparticles as fuel additives on diesel engine operating characteristics

Nanoparticles possess great potential as an additive to enhance biodiesel physiochemical properties improving diesel engine performance, combustion and emission characteristics to meet global emission restrictions and fossil fuels depletion. This investigation deals with the impacts of biodiesel blends and two oxide-based nano additives, aluminum and copper oxides, on single-cylinder compression ignition engine operating characteristics.Fuel blends were tested over variable engine loads from no load to 80% of the peak load while maintaining speed at 2000 rpm. The results reveal that 10% vol biodiesel (B10) results in only a 1% increase in BSFC with no change in heat release rate (HRR) and lower unburned hydrocarbon and carbon monoxide emissions by 40% and 7%, respectively. Optimal concentrations of aluminum and copper oxides nano additives were specified as 150 and 100 mg/L, presenting a 5% and 3% BSFC reduction with a 5.88% and 1.2% increase in HRR, respectively. DA150 also presents a dramatic reduction in unburned hydrocarbon, carbon monoxide, and nitrogen oxide emissions by 38%, 25%, and 23% compared to 45%, 16%, and 12%, respectively, for Dcu100. In comparison, alumina/biodiesel blend B10A150 improves HRR by 5% with a 4% BSFC reduction and 35% and 31% reduction in unburned hydrocarbon and nitrogen oxides.

Impacts of Renewable Energy Generation on Greenhouse Gas Emissions in Saudi Arabia: A Comprehensive Review

Over the last few years, the electric energy demand in the Kingdom of Saudi Arabia (KSA) has increased many folds due to several factors including increased population, industrialization, economic activities, and urbanization. The main source of electric power generation in KSA is the burning of petroleum products. Almost one third of greenhouse gas (GHG) emissions are contributed from the electric power generation sector, mainly, by burning diesel and natural gas. As a result, it makes it necessary to consider alternate forms of electricity generation in order to cut down emissions and to keep sustainable growth alive. The government has planned to diversify energy sources and suppliers. In recent years, energy generation from renewable sources including solar photovoltaic (PV), wind, concentrated solar power (CSP), biomass, geothermal, and tidal, has been given more importance. The ambitious Saudi Vision 2030 targets of 58.7 GW of power generation from renewable energy sources will cause a significant reduction in GHG emissions from the energy sector. This article systematically reviews the impact of renewable energy generation on GHG emissions. The detailed breakdown of GHG emission is discussed. Then, the status of renewable energy generation is investigated, focusing on the technical and economic potentials. The correlation of renewable energy generation and GHG emissions is then explained. The most distinguishing feature of this review is that it provides a comprehensive list of recommendations to reduce GHG emissions. The discussions and recommendations of this article will support decision makers, system planners, industry personnel, researchers, and academics to develop sustainable energy pathways for the Kingdom.

Experimental Evaluation of Pilot and Main Injection Strategies on Gasoline Compression Ignition Engine—Part 1: Combustion Characteristics

<div>Climate change and stringent emission regulations have become major challenges for the automotive sector, prompting researchers to investigate advanced combustion technologies. Gasoline compression ignition (GCI) technology has emerged as a potential solution, delivering higher brake thermal efficiency with ultra-low nitrogen oxides (NOx) and particulate emissions. Combustion stability and controls are some of the significant challenges associated with GCI. This study investigates the combustion characteristics of a two-cylinder diesel engine in GCI mode. GCI experiments were performed using a low-octane fuel prepared by blending 80% (v/v) gasoline and 20% (v/v) diesel (G80). Baseline experiments were conducted in conventional diesel combustion (CDC) mode. These experiments investigated the effects of double pilot injection, first pilot fuel ratio, and the start of main fuel injection timing (10–8°CA before top dead center, bTDC). The results indicated that the GCI mode produced significantly lower (~10%) in-cylinder pressure than the CDC mode. Higher pilot fuel proportions exhibited a lower heat release rate (HRR) at low loads. Retarded main injection showed a lower heat release in the premixed combustion phase than the advanced main injection case at all loads. In addition, retarded main injection timing showed retarded start of combustion (SoC) and end of combustion (EoC). GCI mode exhibited higher cyclic variations than baseline CDC mode, which need to be addressed.</div>

Experimental Evaluation of Pilot and Main Injection Strategies on Gasoline Compression Ignition Engine—Part 2: Performance and Emissions Characteristics

<div>Internal combustion (IC) engines play an important role in the global economy by powering various transport applications. However, it is a leading cause of urban air pollution; therefore, new combustion strategies are being developed to control emissions. One promising advanced low-temperature combustion (LTC) technology is gasoline compression ignition (GCI). This experimental study assesses the performance of a two-cylinder engine, emissions, and exhaust particulate characteristics using G80 (80% v/v gasoline and 20% v/v diesel) blend operating in GCI mode vis-à-vis baseline conventional diesel combustion (CDC) mode using diesel. The effects of double pilot injection, Pilot-1 proportion (10–30%), and main injection timing were investigated on the GCI combustion. Experiments were performed at different engine loads (3, 4, and 5 bar brake mean effective pressure [BMEP]) at a constant engine speed (2000 rpm). GCI combustion showed higher brake thermal efficiency (BTE) than CDC mode at medium loads. Hydrocarbon (HC) and carbon monoxide (CO) emissions increased in GCI mode, but oxides of nitrogen (NOx) were reduced than the baseline CDC mode. High pilot ratio and late main injection timing tests showed higher HC and CO emissions in the GCI mode at low engine loads. The GCI mode engine emitted higher nucleation mode particles and nanoparticles than baseline CDC mode at high engine loads. Using a triple injection strategy, GCI engines simultaneously reduced NOx and particulate matter (PM) emissions, especially at high loads. Controlling these emissions in baseline CDC mode engines is otherwise quite challenging.</div>

Respiratory Health Effects of In Vivo Sub-Chronic Diesel and Biodiesel Exhaust Exposure.

Biodiesel, which can be made from a variety of natural oils, is currently promoted as a sustainable, healthier replacement for commercial mineral diesel despite little experimental data supporting this. The aim of our research was to investigate the health impacts of exposure to exhaust generated by the combustion of diesel and two different biodiesels. Male BALB/c mice (n = 24 per group) were exposed for 2 h/day for 8 days to diluted exhaust from a diesel engine running on ultra-low sulfur diesel (ULSD) or Tallow or Canola biodiesel, with room air exposures used as control. A variety of respiratory-related end-point measurements were assessed, including lung function, responsiveness to methacholine, airway inflammation and cytokine response, and airway morphometry. Exposure to Tallow biodiesel exhaust resulted in the most significant health impacts compared to Air controls, including increased airway hyperresponsiveness and airway inflammation. In contrast, exposure to Canola biodiesel exhaust resulted in fewer negative health effects. Exposure to ULSD resulted in health impacts between those of the two biodiesels. The health effects of biodiesel exhaust exposure vary depending on the feedstock used to make the fuel.

The pivotal role of Ag species on porous nanosheets in the significant reduction of soot ignition temperature

As a major technology, catalytic combustion is now widely used in reducing harmful soot emissions from diesel combustion. However, large amounts of soot are still emitted to atmosphere due to the lower exhaust temperature (below 200 °C) of diesel engines caused by frequent idling and cold start. Therefore, more and continued efforts are still needed to reduce the ignition temperature of T10 (at which 10 % of soot is converted) in terms of energy efficiency and environmental sustainability. In this work, an Ag-supported CoCe porous nanosheets catalyst was developed, through which a T10 < 230 °C was achieved under loose contact mode without the assistance of other atmosphere such as NOx. The detailed characterization of catalysts indicated that the motionless and mobile Ag particles, together with the regulation of valence state of Co ions by the abundant Ag+ species derived from Ag-Co interface are responsible for the ultra-low soot ignition temperature. Density functional theory (DFT) calculations proved that the electronic structure of Co can be tuned by the interactions between Ag and the support, which would promote the adsorption of O2. More importantly, the synergistic effect between Ag and Co, along with the formed interface can lower the dissociation energy barrier of O2, thus achieving a process with fast kinetics. In summary, the appropriate design of catalysts for soot combustion needs to consider both intrinsic activity and morphology, so that a significant reduction of soot emissions from vehicle exhaust can be achieved at low temperature.

An experimental investigation into the combustion properties, performance, emissions, and cost reduction of using heavy and light fuel oils

Heavy fuel oil (HFO) is a fuel that can be used in compression ignition engines because of its cheapness and low operating costs. However, heavy fuel oil is not compatible with most diesel engines and combustion systems in use. As a result, there is a decrease in the efficiency of the combustion process. To treat this problem, and for the purpose of using heavy fuel oil, the characteristics of the diesel engine fuel and combustion system were improved in this study. The high viscosity of heavy fuel oil was reduced (before it was introduced into the engine) by adding a suitable heating device in the fuel line. Light fuel oil (LFO) is also blended with heavy fuel oil to reduce the viscosity of the fuel. HFO properties, such as viscosity, density, calorific value, and sulfur content, were determined. A blend called LFO-H20 (80% LFO:20% HFO) was prepared and tested in a single-cylinder diesel engine. This engine performance and exhaust emissions were evaluated using LFO, HFO (70°C), LFO-H20 and LFO-H20 (70°C). The tests were conducted using a one-cylinder test rig, Kirloskar, which is naturally aspirated, direct injection and has maximum speed of 1500 rpm diesel engine. The results showed that the Brake Thermal Efficiency (BTE) for HFO (70°C), LFO-H20 and LFO-H20 (70°C) was (31.21%, 22.5%, and 10.4%) lower than LFO. The Brake Specific Fuel Consumption (BSFC) also increased by about (28.93%, 20.1%, and 10.5%) compared to LFO. The oxides of nitrogen (NOx) were increased at HFO and single blend fuel by about (19.64%, 11.92%, and 7.53%) compared to LFO. In addition, the unburned hydrocarbon (UHC) for HFO (70°C), LFO-H20 and LFO-H20 (70°C) was (42%, 28.7%, and 18.4%) higher than LFO. The CO concentrations increased by (38.4%, 30.6%, and 18%) compared to LFO. Finally, the smoke opacity values of HFO (70°C), LFO-H20 and LFO-H20 (70°C) were increased by (42%, 26% and 17.2%) respectively. The effect of heating tested fuels at a temperature of (70 °C) resulted in decreasing their density and viscosity, which improved the fuel combustion spray characteristics and enhanced the engine performance and emission.

Computational Investigation of Combustion, Performance, and Emissions of a Diesel-Hydrogen Dual-Fuel Engine

This paper aims to expose the effect of hydrogen on the combustion, performance, and emissions of a high-speed diesel engine. For this purpose, a three-dimensional dynamic simulation model was developed using a reasonable turbulence model, and a simplified reaction kinetic mechanism was chosen based on experimental data. The results show that in the hydrogen enrichment conditions, hydrogen causes complete combustion of diesel fuel and results in a 17.7% increase in work capacity. However, the increase in combustion temperature resulted in higher NOx emissions. In the hydrogen substitution condition, the combustion phases are significantly earlier with the increased hydrogen substitution ratio (HSR), which is not conducive to power output. However, when the HSR is 30%, the CO, soot, and THC reach near-zero emissions. The effect of the injection timing is also studied at an HSR of 90%. When delayed by 10°, IMEP improves by 3.4% compared with diesel mode and 2.4% compared with dual-fuel mode. The NOx is reduced by 53% compared with the original dual-fuel mode. This study provides theoretical guidance for the application of hydrogen in rail transportation.

Self-Adaptive Air-path Health Management for a Heavy Duty-Diesel Engine

This paper presents the air-path health management strategy with the ability to estimate the mass-flows and mitigate (adapt to) the air-path faults in the exhaust system of a heavy-duty diesel combustion engine equipped with a twin-scroll turbine. Based on the engine component models applied in the quasi-steady-state mass-balancing approach, two main engine mass-flow quantities are estimated: the Air mass-flow (AMF) and the Exhaust gas recirculation (EGR) mass-flow. The health management system is monitoring for three kinds of air-path faults that can occur through the combustion engine operation, related either to the after-treatment system, EGR valve, or to the turbine balance valve hardware. For each fault, a fault-mitigation strategy based on in-observer-reconfigurable mass-balance equations with excluded faulty component model and utilized exhaust pressure sensor is proposed. The applied observer is using the iterated Kalman filter (IKF) as the core fault mitigating solver for the quasi-steady-state mass-balancing problem. It is further demonstrated how the individual faults are robustly isolated using the Sequential Probability Ratio Test (SPRT). The strategy and results are validated using the test cycle driving data.

Effect of C4 alcohol and ester as fuel additives on diesel engine operating characteristics

Due to their numerous advantages, diesel engines remain the primary energy source for heavy machinery. In the present experimental study, the effect of oxyfuel type, oxygen content and blend volume on diesel engine performance, combustion and emission characteristics has been investigated. Experiments were carried out on seven fuel blends using a 4-stroke, single cylinder, direct injection combustion ignition (CI) engine at a constant speed of 2000 rpm and varying loads. Four-carbon alcohol (n-butanol) and ester (ethyl ethanoate) were separately blended with pure diesel (D100) at three blending ratios. For each fuel type, two blends were prepared to contain an approximate oxygen mass content of 2.2 % and 4.1 %, then a third blend containing 15 % additive volume ratio was also formulated. All tested blends had minimal effect on in-cylinder pressure and heat release rate (HRR). At low loads, up to 20.9 % rise in brake specific fuel consumption (BSFC) was recorded but EE15 (15 % ethyl ethanoate, 85 % diesel) achieved 15.35 % lower BSFC at 60 % load. NOx emissions reduced for all blends, with n-butanol blends achieving 30.6 % less NOx emissions compared to D100. However, CO emissions increased by up to 37.6 % for n-butanol and 32.9 % for ethyl ethanoate. Considering engine stability, all blends were found to have a stable engine operation. Between the oxyfuel types, EE10.65 (10.65 ethyl ethanoate, 89.35 % diesel) has slightly superior emissions characteristics at equal fuel mass flow rate. Both fuel additives are suitable for CI engine at low blending ratios.

Analysis of energy flows and emission characteristics of conventional diesel and isobaric combustion in an optical engine with laser diagnostics

In this study, the thermodynamic analysis of energy distribution, exhaust emissions, and particulate characterization was conducted in an optical engine with an all-metal configuration. Additionally, the line-of-sight integrated imaging of combustion luminosity, and OH* chemiluminescence along with planar laser induced fluorescence of formaldehyde (HCHO-PLIF), and planar laser induced incandescence of soot (soot-PLII) were applied in the optical configuration. The experiments were conducted with conventional diesel combustion at λ = 3 (i.e., CDC), isobaric combustion at λ = 3 (i.e., Iso3), and isobaric combustion at λ = 4.2 (i.e., Iso4.2) using n-heptane fuel. Compared to Iso3 and CDC, Iso4.2 yielded higher thermal efficiency and lower heat losses; whilst the exhaust losses were exacerbeted. Isobaric combustion also resulted in lower NOx but increased soot emissions. For all operating conditions, the combustion luminosity and OH* chemiluminescence imaging showed that the signal grows and develops from the jet-axis downstream of the nozzle to the jet-wall impingement point, followed by movement towards the squish region. HCHO-PLIF showed that isobaric combustion leads to a faster transition of low-to high-temperature reactions compared to CDC. Soot-PLII showed increased in-cylinder soot distribution for isobaric combustion due to lesser charge pre-mixing time and spray-flame interaction induced by close-coupled injections.

Enhanced CO resistance of Pd/SSZ-13 for passive NOx adsorption

Passive NOx adsorption (PNA) is a novel technology to control NOx emissions during cold start. However, the recent generation of PNA material, Pd/zeolite, suffers from major degradation under high CO concentrations. In this work, we developed a novel form of Pd/SSZ-13 by using a freeze-drying process after incipient wetness impregnation. This Pd/SSZ-13 showed a better stability than the sample synthesized by the common process. Several characterization measurements were conducted and it was found that the Pd sites on the freeze-dried sample were more resistant towards CO-induced agglomeration. By combing in-situ characterization and kinetic modeling, we found that the freeze-dried Pd/SSZ-13 had more ion-exchanged Pd sites, which provided greater resistance towards the CO-induced Ostwald ripening process, and consequently suppressed the sintering behavior under a high CO concentration. This material offers a potentially improved stability of PNAs under extremely high CO concentration pulses from incomplete diesel combustion during engine cold start.

Evaluation of strategies to optimize engine efficiency and NOx emissions with the synthetic diesel fuel oxymethylene ether

The use of CO2-neutral synthetic fuels in internal combustion engines contributes to achieving climate targets. Since their combustion is still associated with pollutant emissions, current research is focusing on minimizing harmful emissions, as well as on improving the efficiency of the combustion. The soot-free combustion of the synthetic diesel fuel oxymethylene ether (OME) opens up new scopes for reducing the remaining pollutants, particularly nitrogen oxides (NOX). Catalytic aftertreatment of NOX is costly and may lead to the generation of further emissions such as nitrous oxide, making it necessary to further investigate engine-internal approaches of NOX reduction. This work shows the influence of various in-engine measures on emissions and efficiency for OME and hydrogenated vegetable oil (HVO) as paraffinic diesel fuel, performed on a 1.75 l single-cylinder research engine. An injector variation was carried out for OME to compensate for the reduced lower heating value by a higher nozzle flow rate, which increases efficiency, but also NOX emissions. The examination of the measures of increasing exhaust gas recirculation, lowering rail pressure, Miller valve timing and high compression ratio shows a significant reduction in nitrogen oxide emissions in each case. At the same time, there is an improvement in indicated efficiency for Miller valve timing and high compression ratio, and with OME, in contrast to HVO, also by reducing the rail pressure. With HVO, each measure increases particulate number by up to several orders of magnitude. For OME, none of the measures resulted in a deterioration of the low particulate emissions, which allows an intensified application and combination of the measures. For example, the simultaneous application of higher compression, early intake closing and decreased injection pressure reduces nitrogen oxide emissions by more than two-thirds and improves efficiency by 5% without increasing particulate emissions.

Experimental investigation of advanced nano materials additives on combustion characteristics of biofuels

Due to the depletion of fossil fuels, renewable and cleaner fuel is now required for diesel engines. The researchers are looking into different kinds of bio-based fuels. It is anticipated that biodiesel will compete with diesel fuel. Pure biodiesel can be used in diesel engines, but due to some drawbacks, including higher density, a lower cetane number, and a lower calorific value, it cannot completely replace conventional diesel. As a result, using biofuel blends in diesel engines is preferred. The role of nanoparticles in biofuel production and the impact of nanoparticles in biodiesel-diesel fuel blends on diesel engine performance, combustion analysis, and emission characteristics are covered in this paper in two different ways. This review study compiles a wide range of findings from earlier research studies on the potential and applications of nanoparticles in the production of bioethanol as well as the impact of their addition to diesel fuel at various biofuel ratios. There are numerous techniques for improving engine performance. Nanoparticles can be used as catalysts in chemical reactions and feedstock pretreatment processes to produce biofuels. According to the overall findings, adding nanoparticles significantly reduced the amount of fuel used for brakes by 20% to 23% when compared to biodiesel-diesel blends with and without the addition of alcohol. In addition to improving the combustion process and boosting the brake power by 2.5% to 4%, nanoparticles have a high thermal conductivity. Emission results revealed that while HC, CO, and PM emissions all significantly decreased in most reviews, NO emissions increased by up to 55%. According to the study's findings, adding nanoparticles to biodiesel and its blends as fuel can make diesel engines run more efficiently, deliver better performance, and produce emissions that are effectively regulated.

Solar energy for the airport ground support equipment – a quantitative study

PurposeThis paper aims to evaluate the hypothetical situation in a resembling airport to Esenboga Airport and analyzes the condition of all ground support equipment (GSE) equipment to be supplied by electricity produced by solar panels mounted on the rooftop of the terminal building. The case is discussed using environmental emissions and economic feasibility. The results of the resembling case can be generalized to all airports for the reduction of emissions caused by ground operations of aviation.Design/methodology/approachGSE fleet data which has been prepared by TGS operated in the Esenboğa Airport have been used to calculate emissions, and equivalent electricity consumption. A hypothetical solar panel construction on the rooftop of the terminal building and also the electricity production case was analyzed. Based on the calculations, both fuel and electricity use cases are compared by means of emissions and production costs using real data.FindingsThe electricity production and transmission pose a high value of emissions. Thus, electrification of GSE in the airport need a new approach such as producing the electric energy in the site. This research analyzes the case that the electricity is produced on the rooftop of terminal building and consumed by the GSE fleet. The authors discussed that it is both feasible and possible to electrify all the GSE except a shortage of two cold months with high fuel demand by using electric storage options.Practical implicationsGround handling is performed by using GSE which is historically powered by diesel and such internal combustion engines which are well known for their high emission rates. As most of the airports reside in populated areas, GSE emissions need to be evaluated for reduction. However the electric energy could be an alternative for GSE emissions reductionOriginality/valueAviation is a system of many subsystems in which the performance of each unit plays a crucial role in the final success of the system. Concerns on environmental protection make the aviation industry focus on reducing emissions produced during operations. Although aircraft emissions are widely discussed in the literature, ground handling systems which are an integral part of the whole aviation system, also need to be studied regarding the environmental issues. Besides, the European Union has set out targets of reducing emissions at the airports during ground operations to zero. This paper discusses the possibility of the target by comparing various scenarios

Volatile organic compounds of diesel and porcine bone in a simulated controlled fire

The detection of burned human remains in a fire is daunting, mainly when identifiable skeletons are not found. This study aims to identify volatile organic compounds (VOC) released from the burning of porcine bones in the presence of diesel in a simulated controlled outdoor setting in Malaysia. Neat diesel was diluted with hexane with a ratio of 1:1 and administered into a gas chromatography-mass spectrometry (GC-MS). Porcine bone was burned to identify VOCs of porcine bones, whereas 30 mL diesel was burned together with porcine bones to identify VOCs produced from the combined burning. After the burning process, an activated carbon tablet was fixed to the burned sample. Later, the tablet was desorbed with hexane and analysed using GC-MS. Results revealed that the combined burning released a set of VOCs that were not detected in burned porcine bone or neat diesel. This work was able to enforce the detection of specific volatiles from various functional groups such as alkanes, isoalkanes, alkylbenzenes and ketones in the combined burning of diesel with porcine bones. It was also discovered that in the specific conditions applied and controlled in this study, most VOCs of porcine bone and diesel respectively were not detected in the combined burning of porcine bone and diesel.

A Computational Investigation of Engine Heat Transfer with Ducted Fuel Injection

Ducted fuel injection (DFI) is an innovative method that curtails or prevents soot formation in direct-injection compression-ignition engines. DFI uses a simple duct, positioned outside each injector hole, facilitating the fuel/charge gas mixing before ignition. This reduces the equivalence ratio below two, in the autoignition zone, which in turn decreases soot formation. But this method also reduces fuel-conversion efficiency. This study investigates the effects of DFI on in-cylinder heat transfer. Experiments with conventional diesel combustion (CDC) and DFI were performed at four different dilution levels. Computational fluid dynamics (CFD) simulations were carried out at conditions matching those of the experiments, and the simulations were validated by the experimental data. The CFD simulations enabled to examine of in-cylinder heat release and temperature distributions. The heat transfer to the piston, head, and cylinder was investigated. The results show that DFI increased the heat transfer to the walls compared to CDC under the same conditions. This could help explain why DFI has been observed to reduce fuel-conversion efficiency by approximately 1% (absolute) relative to CDC under certain conditions. The efficiency loss typically decreases with dilution, such that DFI can improve fuel-conversion efficiencies relative to CDC at higher dilution levels.

Improving the energy and environmental performance of a diesel internal combustion engine by using a hydrogen-containing additive

BACKGROUND: The areas of hydrogen energetics development are analyzed. The main problems faced by Western automakers and which determine the ways to solve the problems of hydrogen vehicles are outlined. It is noted that small-scale production of hydrogen cars has already begun in Europe and the USA. The development of this direction requires the creation of a network of filling stations, which is related to the high financial cost of hydrogen fuel production technologies and the development of the appropriate infrastructure. The world economy transition to a new energy source requires the introduction of large electrical capacities.&#x0D; AIMS: Technologies of vehicle onboard hydrogen production with use of hydrogen-containing substances are of interest of the study, as they are highly safe, cheap in production and easy in service.&#x0D; METHODS: The experimental design developments on converting diesel and gasoline internal combustion engines to run on hydrogen, made by NAMI in the past years, are considered. In the development of this direction, MADI has developed an original method for vehicle onboard hydrogen production with hydrogen supply to the cylinders of a bifuel diesel internal combustion engine.&#x0D; RESULTS: During the tests, an increase in power indicators, an increase in the effective efficiency of the internal combustion engine and a decrease in the content of CH and CO in the exhaust gases of a diesel engine with a certain increase in nitrogen oxides were obtained.