Real Diesel Engine Research Articles

Non-PGM hollow fibre-based after-treatment for emission control under real diesel engine exhaust gas conditions

Hollow fibre (HF)-based technologies for emission control, as an alternative to the traditional monolithic technology, offers a promising route to the uptake of non-PGM catalytic systems. In this work, a series of Cu-doped LaCoO3 perovskites were investigated as potential non-PGM Diesel Oxidation Catalysts (DOC). Two HF-based modules, comprising single-channel (i.e., 1CM) and four-channel (i.e., 4CM) HFs respectively, were impregnated with the best catalyst candidate, and their performance was tested under real exhaust gas conditions, using a single-cylinder diesel engine. Compared to the 1CM, the 4CM demonstrated enhanced CO conversion, and reduced performance towards Total Hydrocarbon (THC) conversion. Overall, these findings reveal the influence of HF morphology on catalytic performance, and in turn, will contribute towards the refinement of HF-based technology for emission control, as well as enabling the transition towards non-PGM catalytic systems.

High Performance and Stackable Trampoline Like‐Triboelectric Vibration Energy Harvester for In‐Situ Powering Sensor Node with Data Wirelessly Transmitted Over 1000‐m

AbstractAddressing the power supply challenges of wireless sensor nodes is pivotal for advancing the development of the Internet of Things (IoT). This work proposes a high performance and stackable trampoline like‐triboelectric vibration energy harvester (T‐TVEH) that can efficiently harvest ultra‐wideband vibrational energy for in‐situ powering of sensor nodes. The unique structural design and material selection enables T‐TVEH to represent a breakthrough in terms of both working bandwidth and power density compared to recent research efforts of vibration energy harvesting. Specifically, the working bandwidth and the peak power density of T‐TVEH is 192 Hz and 5.9 W m−2, which are higher than previous related studies by 156% and 59.2%, respectively. Based on the excellent performance of the T‐TVEH, a wireless sensor node for monitoring machinery condition is constructed. Temperature, humidity, and frequency information are successfully acquired and transmitted to 1000‐m through the wireless sensor node, which is nine times improved compared to related studies. Meanwhile, it achieves fully self‐powered wireless operation monitoring and abnormal alarm on a real ship's marine diesel engine. Overall, this study proposed an innovative solution for in‐situ power supply of wireless sensor nodes, which has broad application prospects in the field of the IOT.

Role of Vanadium in Thermal and Hydrothermal Aging of a Commercial V2O5-WO3/TiO2 Monolith for Selective Catalytic Reduction of NOx: A Case Study

In recent years, increased attention to air pollutants such as NOx has led the scientific community to focus meaningfully on developing strategies for NOx reduction. Selective catalytic reduction of NOx by ammonia (NO SCR by NH3) is currently the main method to remove NOx from diesel engine exhaust emissions. The catalysts with typical V2O5-WO3/TiO2 (VWTi) composition are widely used in NH3-SCR for their high NOx conversion activity, low cost, and robustness, especially concerning sulfur poisoning. However, in real diesel engine working conditions, the thermal and hydrothermal aging of catalysts can occur after several hours of operation at high temperature, affecting the catalytic performance. In this study, the stability of a commercial VWTi monolith, self-supported and containing glass fibers and bentonite in its matrix, was investigated as a case study. In laboratory conditions, NO SCR tests were performed for 50 h in the range of 150 to 350 °C. Subsequently, the VWTi monolith was thermally and hydrothermally aged at 600 °C for 6 h. The thermal aging increased the NOx conversion, especially at low temperature (<250 °C), while the hydrothermal aging did not affect the SCR. The differences in NOx conversion before and after aging were associated with the change in vanadium and tungsten oxide surface coverage and with the reduction in the surface area of catalysts. In order to correlate the change in SCR activity with the modifications occurring after aging processes, the monolithic samples were characterized by several techniques, namely XRD, SSA and pore analysis, TPR, XPS, Raman, TGA and SEM/EDX.

Assessing risk of AR and organizational changes factors in socio-technical robotic manufacturing

Technological changes such as the use of Augmented Reality (AR) along with the advent of new organizational changes such as digitalization are on the one hand positively changing the way of working but on the other hand they are introducing new risks, potentially leading to not only normal but also post-normal accidents. In our previous work, we have incrementally proposed a novel framework, called FRAAR, for risk assessment of AR-equipped socio-technical systems (i.e., systems integrating human, organizational and technical entities (such as AR)). We have also partly evaluated our framework via an industrial automotive study and by providing comparison and positioning with respect to other related works in a systematic literature review. In this paper, we conduct a new study to evaluate the applicability and effectiveness of our framework in a different domain. To do that, we choose a digitalized socio-technical factory system, focusing on the human–robot collaboration for a realistic diesel engine assembly task using AR-based user interface in an organization affected by organizational changes. Then, we design and execute our study to apply our framework and we discuss about the extent the conceptualizations provided by the framework are effective to capture the essential information for risk assessment in socio-technical robotic manufacturing, the extent the robotic safety standards are supported (to demonstrate the applicability of the framework in the robotic domain) and the extent of effectiveness of the risk assessment with respect to AR and organizational changes. Finally, we discuss about validity of our work and we provide our findings and intended future work.

Coaxial Flexible Fiber-Shaped Triboelectric Nanogenerator Assisted by Deep Learning for Self-Powered Vibration Monitoring.

Self-powered vibration sensor is highly desired for distributed and continuous monitoring requirements of Industry 4.0. Herein, a flexible fiber-shaped triboelectric nanogenerator (F-TENG) with a coaxial core-shell structure is proposed for the vibration monitoring. The F-TENG exhibits higher adaptability to the complex surfaces, which has an outstanding application prospect due to vital compensation for the existing rigid sensors. Initially, the contact characteristics between the dielectric layers, that related to the perceiving performance of the TENG, are theoretically analyzed. Such a TENG with 1D structure endows high sensitivity, allowing for accurately responding to a wide range of vibration frequencies (0.1 to 100Hz). Even applying to the real diesel engine, the error in detecting the vibration frequencies is only 0.32% compared with the commercial vibration sensor, highlighting its potential in practical application. Further, assisted by deep learning, the recognition accuracy in monitoring nine operating conditions of the system achieves 97.87%. Overall, the newly designed F-TENG with the merits of high-adaptability, cost-efficiency, and self-powered, has offered a promising solution to fulfill an extensive range of vibration sensing applications in the future.

Deploying OWL ontologies for semantic mediation of mixed-reality interactions for human–robot collaborative assembly

For effective human–robot collaborative assembly, it is paramount to view both robots and humans as autonomous entities in that they can communicate, undertake different roles, and not be bound to pre-planned routines and task sequences. However, with very few exceptions, most of recent research assumes static pre-defined roles during collaboration with centralised architectures devoid of runtime communication that can influence task responsibility and execution. Furthermore, from an information system standpoint, they lack the self-organisation needed to cope with today’s manufacturing landscape that is characterised by product variants. Therefore, this study presents collaborative agents for manufacturing ontology (CAMO), which is an information model based on description logic that maintains a self-organising team network between collaborating human–robot multi-agent system (MAS). CAMO is implemented using the Web Ontology Language (OWL). It models popular notions of net systems and represents the agent, manufacturing, and interaction contexts that accommodate generalisability to different assemblies and agent capabilities. As a novel element, a dynamic consensus-driven collaboration based on parametric validation of semantic representations of agent capabilities via runtime dynamic communication is presented. CAMO is instantiated as agent beliefs in a framework that benefits from real-time dynamic communication with the assembly design environment and incorporates a mixed-reality environment for use by the operator. The employment of web technologies to project scalable notions of intentions via mixed reality is discussed for its novelty from a technology standpoint and as an intention projection mechanism. A case study with a real diesel engine assembly provides appreciable results and demonstrates the feasibility of CAMO and the framework.

Role of Altitude in Influencing the Spray Combustion Characteristics of a Heavy-Duty Diesel Engine in a Constant Volume Combustion Chamber. Part I: Free Diesel Jet

Heavy-duty diesel engines operating in plateau regions experience deteriorated combustion. However, the lack of up-to-date information on the spray-combustion process limits the fundamental understanding of the role of altitude. In this work, the in-cylinder thermodynamic conditions of a real diesel engine operating under different altitudes were reproduced in a constant-volume combustion chamber (CVCC). The liquid spray, ignition, and combustion processes were visualized in detail using different optical diagnostics. Apart from predictable results, some interesting new findings were obtained to improve the understanding of free spray-combustion processes with different altitudes. The spatial distributions of ignition kernels provided direct evidence of higher peak pressure rise rates for high-altitude diesel engines. The percent of stoichiometric air was calculated to confirm that the net effect of altitude was an increase in the amount of air-entrained upstream of the lifted flame; therefore, the soot levels deduced from flame images were inconsistent with those from real engines, revealing that accelerating the soot oxidation process could effectively reduce engine soot emissions in plateau regions. Finally, a novel schematic diagram of the spray flame structure was proposed to phenomenologically describe the role of altitude in influencing the spray-combustion process of a free jet.

The Investigation of the Mixture Formation and Combustion Characteristic of the Spray-wall Impingement

In recent years, investigations into the formation of mixture or combustion characteristics of diesel spray-wall impingement have been summarized. On one hand, the air entrainment strength and fuel concentration distribution in the near-wall area during the spray-wall collision process have been studied. On the other hand, the combustion characteristics of the impinged spray, including ignition and combustion characteristics, have also been discussed. Additionally, the effect of impingement between spray and wall on real diesel engines’ operating condition has been analyzed and summarized. Results showed that increasing the pressure of the injection and shortening the collision distance could enhance the air entrainment strength of spray-wall impingement. Moreover, increasing the injection pressure, shortening the impingement distance, decreasing the environmental pressure, increasing the wall temperature, and reducing the nozzle diameter all improved the mixture formation. Conversely, reducing the environmental temperature, decreasing the nozzle diameter, and increasing the impingement distance all reduced the concentration of soot, and even achieved no soot formation. Under real diesel engine operation conditions, some of the soot formed in the spray-wall collision and deposited on the wall. The structure of these deposits was mainly a simple cluster structure composed of several basic particles, and the porous structure of the deposits was conducive to the oxidation of soot and reduced the deposition rate.

Numerical investigation of natural gas (NG) as low reactivity fuel in a reactivity controlled compression ignition (RCCI) engine model

Natural Gas (NG) with its high octane number and low C/H ratio is beneficial for reactivity controlled compression ignition (RCCI) engines in controlling the rate of pressure rise and lower the emissions, given that these engines still suffer from these two problems. Therefore, in this study, a detailed 3D combustion model was developed in ANSYS-Forte environment on the scanned image of a real single-cylinder diesel engine for the application of NG to RCCI engines and then validated with the experimental data of the same engine. Afterward, the effect of NG premixed ratio (Rp, 15%, 30% and 45%) on the combustion and emission characteristics of the RCCI engine were analyzed at 20% load and 2400 rpm. Results showed that by increasing the Rp, the heat release rate and cylinder pressure decreased while the ignition delay (ID) period increased. Moreover, NOx and HC emissions were observed to be increased whereas CO and C2H2 emissions tended to be declined as Rp increased. CO emissions were decreased up to 29% when RCCI mode was applied. Also, C2H2 emissions were reduced by about 97% by RCCI compared to CDM. However, engine efficiency started to decrease as Rp increased.

Fault location in a marine low speed two stroke diesel engine using the characteristic curves method

<abstract><p>When a malfunction occurs in a marine main engine system, the impact of the anomaly will propagate through the system, affecting the performance of all relevant components in the system. The phenomenon of fault propagation in the system caused by induced factors can interfere with fault localization, making the latter a difficult task to solve. This paper aims at showing how the "characteristic curves method" is able to properly locate malfunctions also when more malfunctions appear simultaneously. To this end, starting from the working principle of each component of a real marine diesel engine system, comprehensive and reasonable thermal performance parameters are chosen to describe their characteristic curves and include them in a one-dimensional thermodynamic model. In particular, the model of a low-speed two stroke MAN 6S50 MC-C8.1 diesel engine is built using the AVL Boost software and obtaining errors lower than 5% between simulated values and test bench data. The behavior of the engine is simulated considering eight multi-fault concomitant phenomena. On this basis, the fault diagnosis method proposed in this paper is verified. The results show that this diagnosis method can effectively isolate the fault propagation phenomenon in the system and quantify the additional irreversibility caused by the Induced factors. The fault diagnosis index proposed in this paper can quickly locate the abnormal components.</p></abstract>

Экспериментальное исследование ресурса цилиндропоршневой группы судовых двигателей внутреннего сгорания при использовании различных смазочных композиций

The paper presents the results of a model experimental study of the resource of the mating parts “piston ring - cylinder liner” of a marine diesel engine. A medium-speed trunk engine 6Ch36/45 of medium boost was chosen as a real diesel engine under study. An experimental study was carried out by using an antiwear additive containing molybdenum diselenide MoSe2 to a lubricating oil similar to that used in a circulating lubrication system. The studies are supplemented by a calculation model of the resource of the mating parts “piston ring - cylinder liner” followed by a comparison of the calculated values with the obtained experimental data. The following parameters mainly influence the resource of the selected tribological mating: the contact pressure of rubbing surfaces, the additive concentration in the oil, the shelf life of the additive before it is added to the oil without mixing it. The life tests of the parts of the “piston ring - cylinder liner” mating of a marine diesel engine made it possible to identify the effective concentration of the additive in oil by the formula Ci = 0.5÷1.0 vol. %. The resource of parts of the friction pair “piston ring - cylinder liner” increases by 1.28÷1.67 times in relation to the standard parameters of the 6Ch36/45 diesel engine. Non-compliance with the storage conditions of the additive before adding it to the oil can reduce the resource performance relative to the normative standards for of this diesel engine by 1.7÷3.45 times. It has been proved that the developed mathematical model of the service life of the parts that make up the tribological mating “piston ring - cylinder liner” has a high convergence (relative error 0.5÷5%) with the results of the experiment on the physical model of the studied friction pair “piston ring-cylinder liner”. There has been studied the influence of the volume concentration Ci of an antiwear additive on the calculated and experimental indicators of the marine diesel engine resource, the optimal value of which should not be lower than 1.0%, while the value of the contact pressure in the friction pair is up to 1.0 MPa, the time of preliminary storage of the additive is no longer than 36 hours. It has been recommended to apply the developed mathematical model to estimate the resource of the friction pair “piston ring - cylinder liner” for high- and medium-speed internal combustion engines.

Modified quantitative systems theoretic accident model and processes (STAMP) analysis: A catastrophic ship engine failure case

Despite the rapid advancement of technology and the increasing complexity of systems, conventional accident analysis techniques developed many years ago are still used in numerous sectors. On the other hand, these approaches are limited in detecting all underlying causes of accidents in complex socio-technical systems. In recent years, system theory-based novel accident analysis techniques have been proposed to address this issue. Systems-Theoretic Accident Model and Processes (STAMP) is one of these innovative analytic techniques with a strong detection capability. The method has the ability for analyzing human, organization, hardware, software, external factor components, and their interactions in a dynamic structure. However, despite the method's strong analysis capacity, it is a shortcoming that STAMP is a qualitative method. This study aims to present a hybrid quantitative methodology for complex system accidents based on a system engineering perspective to fill this gap. In this context, a real catastrophic marine diesel engine incident was analyzed to prove the applicability and effectiveness of the methodology. According to the analysis results, the main causes of the case incident were systematically determined as 80% human factor, 13% hardware & software factor, and 7% external factor.

Effects of Diesel-Biodiesel-Ethanol Fuel Blend on a Passive Mode of Selective Catalytic Reduction to Reduce NO x Emission from Real Diesel Engine Exhaust Gas.

The effects of ethanol on combustion and emission were investigated on a single-cylinder unmodified diesel engine. The ethanol content of 10–50 vol % was chosen to blend with diesel and biodiesel fuels. Selective catalytic reduction (SCR) of nitrogen oxides (NOx) in the passive mode was also studied under real engine conditions. Silver/alumina (Ag/Al2O3) was selected as the active catalyst, and H2 (3000–10000 ppm) was added to assist the ethanol-SCR. The low cetane number of ethanol resulted in longer ignition delay. The diesel–biodiesel–ethanol fuel blends caused an increase in fuel consumption due to their low calorific value. The brake thermal efficiency of the engine fuelled with relatively low ethanol fraction blends was higher than that of diesel fuel. Unburned hydrocarbons (HC) and carbon monoxide (CO) increased, while NOx decreased with ethanol quantity. The higher ethanol quantity led to increases in the HC/NOx ratio which directly affected the performance of NOx-SCR. Addition of H2 considerably improved the activity of Ag/Al2O3 for NOx reduction. The proper amount of H2 added to promote the ethanol-SCR depended strongly on the temperature of the exhaust where a high fraction of H2 was required at a low exhaust temperature. The maximum NOx conversion of 74% was obtained at a low engine load (25% of maximum load), an ethanol content of 50 vol %, and H2 addition of 10000 ppm.

Implementing Simulationx in the Modelling of Marine Shafting Steady State Torsional Vibrations

Abstract Marine propulsion shafting systems are exposed to torsional vibrations originating from excitations in their prime movers and propellers. It is essential to analyse their steady state response in the earliest stage of ship design. The paper describes the implementation of SimulationX software based upon simulation modelling for these calculations. This software can be used either by the design office of the shipyard or by the classification society for verification within the plan approval phase. Some specifics of the input data preparation are briefly discussed. In addition, the simulation results depend on the modelling approach chosen. For these reasons, the real two-stroke Diesel engine ship propulsion system was chosen and several different models were implemented for system modelling. SimulationX calculation results are compared with those of two well-known and field-proven programs that use an analytical approach. Finally, the results are compared with the measurements performed on the actual newly built ship. Discussion reviews the selected SimulationX model, and its verification and validation in the case of engine cylinders with normal ignition.

Review of Discharge Plasma Treatment of NO X in Diesel Engine Exhaust: Progress in Stand-Alone and Cascaded Measures

This article is intended to provide a comprehensive review of the experimental studies conducted to understand the effect of several parameters involved in the discharge plasma-based nitrogen oxides (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</sub> ) removal from real diesel engine exhausts, be it stationary or automobile, in addition to simulated ones. In the last two decades, much progress has occurred in the electric discharge-based nonthermal plasma (NTP) treatment of exhaust gas with or without cascading any additional treatment technique, such as catalysts or adsorbents. Most of these studies were conducted with the aim of enhancing the removal of NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</sub> or studying the efficacy of a particular parameter on NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</sub> removal or both. It is now timely to collage the findings of these studies in a way to help the present researchers to understand the effect of various parameters/measures associated with stand-alone and cascaded NTP treatments for NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</sub> removal. It is also intended that the current review helps in moving closer to realizing the application of NTP in the cleansing of gaseous pollutants of diesel exhaust.

Investigation of deactivation effect of Au addition to Ce/TiO2 catalyst for selective catalytic reduction using real diesel engine exhaust samples at low temperature conditions

AbstractBACKGROUNDNOx emissions are very toxic and cause serious adverse environmental effects. NOx reduction technologies have been developed due to the harmful effects of NOx and increasingly stringent emission standards which apply in many countries. Selective catalytic reduction (SCR) is the most effective method of removing NOx from engine exhaust. The suitable active catalysts are important for providing higher NOx conversion efficiencies in the SCR system. Catalyst production methods affect catalytic activity due to change in elemental composition, morphology, dispersion of catalytic elements, and total surface area. In this study, de‐NOx performance of Ce/TiO2 and Au‐Ce/TiO2 catalysts were investigated with real exhaust gases. Tests were carried out within 200–300 °C temperature range to evaluate low temperature performance of the catalysts. Cordierite material was used as the support material and pre‐treated with hot acid solution to enhance surface area. Ce content of synthesized catalysts with impregnation method was adjusted as 4 wt% and Au content as 0.4, 0.8, and 1.6 wt%. The catalysts were characterized with Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET), X‐Ray Diffractometer (XRD), and Fourier transform infrared spectroscopy (FT‐IR) analysis.RESULTSMaximum NOx conversion ratios obtained at 300 °C with the Ce/TiO2, 0.4 Au‐Ce/TiO2, 0.8 Au‐Ce/TiO2, and 1.6 Au‐Ce/TiO2 catalysts were 95.1%, 92%, 92.6%, and 90.2%, respectively.CONCLUSIONSThe results showed that in general, de‐NOx effect of the Ce/TiO2 catalyst was greater than the Au doped Ce/TiO2 catalysts. Au addition adversely affected surface properties of the catalyst and therefore activity of the Au‐Ce/TiO2 catalysts decreased. © 2021 Society of Chemical Industry (SCI).

Implementation of multi-component diesel fuel surrogates and chemical kinetic mechanisms for engine combustion simulations

Recent developments have led to the formulation of multi-component surrogates that closely match physical and chemical properties of diesel fuels. These surrogates have been characterized and extensively tested in constant pressure vessels as well as engine experiments. The adoption of such surrogates in simulations is an important step towards predictive engine simulations. However, significant challenges remain in adoption of such surrogates. The complex chemical kinetics associated with a multi-component fuel leads to an extremely large and stiff chemistry mechanism with thousands of species. Such chemistry mechanisms are prohibitive to be directly used in engine simulations using traditional solvers due to the excessively-high computational cost. This work describes some of the experimental investigations of a 4-component diesel fuel surrogate in constant volume combustion chambers that provide useful validation datasets for numerical models. In addition, a chemical kinetic mechanism for the multi-component diesel surrogate with 1544 species is proposed. A previously validated unsteady flamelet model, accelerated by a sparse solver and analytical Jacobian, is used to implement large chemistry mechanisms for realistic diesel engine simulations. A flamelet solver is used to generate multi-dimensional unsteady flamelet libraries for the multi-component surrogate for a range of conditions. This approach is then used in a large eddy simulation (LES) framework to model combustion of the 4-component surrogate in a constant pressure spray vessel over a range of ambient oxygen conditions. The current chemistry mechanism and computational methodology can capture the two-step ignition delay as well as flame lift-off length trends observed in the experiments. Some of the low temperature combustion characteristics are analyzed in detail. The computational setup and the validation results demonstrate the feasibility of using these latest multi-component fuel surrogates for engine simulations by leveraging multi-dimensional chemistry tabulation methods.Highlights:1. Detailed experiments with the multicomponent V0A surrogate were carried out in the High Temperature Pressure Vessel facility.2. A detailed chemistry mechanism with 1544 species was developed for the V0A surrogate.3. The LSODES based flamelet tabulation method was used to implement and validate these high-fidelity surrogates and mechanisms in engine relevant LES calculations.

Real diesel engine exhaust emission control: indirect non-thermal plasma and comparison to direct plasma for NOX, THC, CO, and CO2.

Recently, diesel engine exhaust emission control by non-thermal plasma (NTP) technology has been shown to be promising. However, carbon and soot deposition on the inner surface of the NTP reactor for direct plasma processing decreased the efficiency of the plasma process throughout the experiments. In the present work, the feasibility of indirect plasma processing was investigated as an innovative and novel method compared to direct plasma processing. Air was directed through an NTP at an applied voltage of VP-P = 7kV and a flow rate of 1-4L/min, and then, it was combined with engine exhaust gas at a flow rate of 5L/min. In this case, the maximum conversion of NOX was 64.9% at 4L/min. However, for direct plasma processing at 5L/min, NO conversion was 58%, which proves that the indirect NTP process can decrease NOX concentration effectively. The maximum conversion for unburned hydrocarbon (UHC), carbon monoxide (CO) and carbon dioxide (CO2) was obtained as 2%, 4% and 0.7% at 4, 2 and 3L/min in indirect plasma processing; While their remove rate for direct plasma processing was 16.3%, -0.5% and 13.2%, respectively.

Evaluation of Catalysts Derived from Palm Kernel Shell Carbon in a Passive NOx Removal from a Diesel Engine Exhaust

Carbon-supported de-NOx catalysts have attracted much attention lately due to their reactivity at low temperature, where it is usually challenging to remove NOx from mobile emission sources such as light-duty diesel-powered vehicles. In addition, passive mode of NOx removal system is preferable due to the absence of a reductant injection requirement, which could add an extra cost to the system. Palm kernel shell activated carbon (PKS) was used to synthesize SCR catalysts by precipitating manganese (Mn) and/or cerium (Ce) oxides. The catalysts were characterized using nitrogen adsorption-desorption experiment, X-ray fluorescence analysis (XRF), hydrogen temperature-programmed reduction (H2-TPR) and Fourier-Transform infrared spectroscopy (FTIR). The experiment of NOx removal from a real diesel engine exhaust system revealed that Mn/PKS exhibited the highest NOx removal at 74% and at the lowest temperature of 140 °C. This was attributed to the high surface area and micropore volume, high metal loading, enhanced hydroxyl and carbonyl functional groups and the presence of reducible MnO2 species. Therefore, it is expected that this type of catalyst may serve as a cost-effective material for a sustainable alternative to the current practice in removing NOx from diesel engine vehicles.

Examining the role of hexagonal boron nitride nanoparticles as an additive in the lubricating oil and studying its application

Lubricating oil plays an important role in minimizing the friction and wear of many mechanical systems. The additives present in the conventional lubricant are inadequate to reduce the friction and wear of today’s mechanical systems. However, the use of these additives has a significant effect on the environment due to their fast chemical degradation. In recent years, nanoparticle-based lubricant has attracted great attention due to their friction reduction behavior. Therefore, it is of great importance to examine the role of nanoparticle addition in the conventional lubricant and its influence on the tribological characteristics of the mechanical systems. Hence, this research work focused on the formulation of hexagonal boron nitride nanoparticle-based nanofluids and its effect on the tribological characteristics of cylinder liner and piston rings of a realistic diesel engine. The different concentrations of hBN nanoparticle-based nanofluids were formulated and characterized using the ultraviolet–visible spectroscopy and the thermal gravimetric analysis. The results of the experimental analysis showed that hBN nanoparticles as an additive in the lubricating oil exhibited better anti-wear and friction reduction behavior than the conventional base oil 20W40.