IC Engine Applications Research Articles

Acoustic properties of perforates - experimental data and empirical models

Sound reducing treatment in for instance aircraft engine and IC engine applications often involve the use of perforates. In these applications they are exposed to fluid flow and high-level acoustic excitation, and this influences the acoustic properties of the perforate, as is well known from many published papers. The acoustic properties are usually described using a transfer impedance. The transfer impedance of a perforate sample has been studied using both a conventional impedance tube (two-port) setup and an innovative three-port setup. The three-port configuration made it possible to study both the effect of grazing flow and high-level excitation effects separately as well as jointly. In the present paper these recent experimental results are presented and comparisons are made with results from previously published papers and empirical models.

Downcycling of one-time used plastic waste to DICI engine combustion energy through pyrolysis with less NOx emission

Plastic waste elimination is more important for environmental pollution. Alternate fuel is essential for future IC engine applications because of fossil fuel availability. This study focuses on both challenges by creating combustion energy for direct injection CI engines from the wastes with lesser NOx emissions. Plastic wastes of low-density polyethylene (LDPE) have the most negligible recycling value based on their collection point of view from municipal wastes. Conversion of this LDPE plastic waste into alternate fuel for CI engines by pyrolysis will provide value for that waste. The combustion, emission, and performance of neat pyrolyzed oil of LDPE plastic wastes (POLPW) were studied with exhaust gas recirculation (EGR; 0%, 10%, and 20%) in a 1500 rpm 5.2 kW engine on different loads. 20% of EGR used POLPW fuel produced 31.63% of brake thermal efficiency and 62.28% reduction in NOx (596 ppm) than diesel at maximum load. Pyrolyzed oil of low-density polyethylene plastic wastes can be utilized as a 100% substitute fuel in CI engines with an EGR of 20%. This will provide alternate fuel and low-value plastic waste downcycling, initiating environmental pollution reduction.

Tribological behavior of H-DLC and H-free DLC coatings on bearing materials under the influence of DC electric current discharges

In automotive industry, most of the moving components and lubricants are currently being reengineered in order to meet the much harsher operating conditions of electric vehicles (EVs). Diamond-like carbon (DLC) coatings have been widely used in automotive field mainly because of their lower friction and wear coefficients, high chemical inertness, corrosion resistance, and hardness. It is also possible that DLC coatings can afford very desirable tribological properties to the bearings and gears of electric vehicles. In addition, their superior dielectric properties could also be very ideal for such applications. In EVs, current leakages in the powertrain are very common and these can adversely impact the tribological behavior of bearings and/or other moving mechanical elements. Although DLC coatings provide superior tribological performance in IC engine applications, they have not yet been evaluated under electrified sliding conditions of EVs. In this work, two different types of DLC coatings (Hydrogenated DLC (H-DLC) and hydrogen-free DLC (H-free DLC) were produced on AISI 52100 steel substrates and tested using a ball-on-disc tribometer under non-electrified and electrified (DC, 3A) both dry and lubricated sliding conditions. Coefficient of friction (CoF), wear volumes, wear modes and mechanisms have been assessed and reported. The results showed that electrification can cause a decrease in CoF for baseline steel-on-steel contacts, but an increase for H-free DLC in lubricated condition. The change in CoF of H-DLC interface was negligible. However, electrification caused a significant increase in the wear volume of steel-on-steel and H-free DLC-coated surfaces, but little or no wear was observed for the H-DLC-coated cases in both dry and lubricated test conditions. Overall, the tribological behavior of H-DLC was almost unaffected by electrification, suggesting that one has to select the right kind of DLC for applications involving electrified contact conditions.

Influence of nano AL2O3 on compression ignition engine characteristics fuelled with Mahua biodiesel

Growing energy demand and rising emissions have prompted testing on alternative energy sources for IC engine applications. Alternative energies are commonly extracted from biomass waste, algae and plant seeds. Many environmental difficulties develop as a result of the use of petroleum products in IC engines. As a result, adapting an alternative fuel to an existing engine may necessitate some design changes in order to achieve greater or nearly equal performance of conventional fuels. The primary objective of this experiment is to increase the efficiency of the engine and reduce the concentration of HC, CO2 and NOx. The experimental investigation was assessed in a single cylinder, compression ignition engine fuelled with mahua biodiesel and its diesel blends with AL2O3 nano additive. The engine was analysed with different test fuels such as Diesel, 10 % mahua biodiesel + 90 % diesel (B10), 20 % mahua biodiesel + 80 % diesel (B20), 70 % diesel (B30) at different load conditions. From the tested fuel, 20 % mahua biodiesel + 80 % diesel (B20) showed reasonable performance and tail pipe emission compared to other biodiesel blends. The preparation of nano blended biodiesel was based on 80 % of Diesel, 20 % of mahua biodiesel and 10, 25, 50 ppm of nano AL2O3. The 50 ppm of nano AL2O3 blended biodiesel shows better thermal efficiency and reduced emissions due to presence of nanoparticle in the blends which enhance the fuel atomization characteristics. BTE of 50 ppm of nano AL2O3 blended biodiesel increased 6.05 %, when compared with the diesel. The emission of HC, CO, NOx, and Smoke by 50 ppm of nano AL2O3 blended biodiesel was reduced by 19.52 %, 29.81 %, 14.48 %, and 23.35 %, respectively when correlated to base fuel. On whole, it was concluded that nano AL2O3 blended mahua biodiesel found to be a better alternative energy for unmodified existing CI engine.

Effect of additives on the stability of ethanol-diesel blends for IC engine application.

The present research work was conducted on a compression ignition engine to assess the engine characteristics fueled with the blend of diesel and high-oxygenated additives such as ethanol. Ethanol does not easily blend with diesel. In order to attain a homogeneous mixture, a small amount of additive is added to the blend. Different additives were added to the blend to form a homogeneous mixture. Stability test was conducted on the blend to ensure prolonged homogeneity. The additives used for the test purpose were isopropanol, oleic acid, and ethylene acetate. From the stability results, it was found that oleic acid was the best additive which produces a better homogenous mixture for the blend of ethanol and diesel. One percentage of oleic acid is used as an additive to blend ethanol and diesel. The different combinations of blend ratios used for the test purpose were D90E10, D80E20, and D70E30. All the aforementioned blends have low cetane number because of ethanol, which was compensated by adding 1% DEE (diethyl ether) to all the blends. Experimental results exhibit that there is an improvement in the performance characteristics, such as brake thermal efficiency (BTE) and specific energy consumption (SEC), with the enrichment of DEE in ethanol-diesel blend. It is also noticed that the blend without DEE exhibited lower magnitude. This is mainly due to higher energy content and cetane number of DEE. Emission characteristics, like hydrocarbon (HC) and carbon monoxide (CO), were found to drastically increase with the increase in the ethanol concentration in the diesel blend. This is attributed to higher latent heat of vaporization (LHV) of ethanol present in the blend. Combustion pressure and heat release rate of the DEE-enriched ethanol blends were higher by 2.2 % and 2.4 %, respectively, when compared with their corresponding blends without DEE. This is a result of higher volatility of DEE which leads to better combustion. Graphical abstract.

An interdisciplinary review on calibration strategies of engine management system for diverse alternative fuels in IC engine applications

As the vehicle technology evolves and becomes more complex, the ability to monitor certain uncontrollable factors is possible through various engine management system calibration methods. Additionally, different optimization approaches assist in improving engine output characteristics. Advances in fuel production from unique feedstocks have paved a way for the introduction of innovative flex-fuel engines. These engines are made multi-fuel adaptive by utilizing appropriate calibration and optimization approaches. Since numerous researches have been carried out in internal combustion engine calibration, operating on alternative fuels, it is quite hard to maintain a record for this wealth of information. Therefore to bridge this issue, this study intends to organize and provide the reader with a retrospective view of selective studies undergone in the field of engine calibration using different tuning techniques. The objective of this study is to assist engine calibration enthusiasts on selecting an apt engine calibration technique for their application which can be flexible for multiple fuel types. Studies revealed that model-based calibration assisted by Gaussian process modelling and Design of Experiment application is adequate for calibrating an engine operating on alternative fuels. Additionally, calibration methodologies followed for certain fuel types and compositions are highlighted in detail. Furthermore, an advanced calibration methodology is proposed for flex-fuel engines in this study based on the knowledge gained through the preparation of this article. To further enhance accuracy, complex optimizers like neural networks can be used in the proposed methodology to initiate real-time calibration for ideal flex-fuel engine output responses.

Cottonseed Trimethylolpropane TMP Ester as Lubricant and Performance Characteristics for Diesel Engine

Many researchers have been working on bio-based lubricant which is complete or partial replacement for mineralbased lubricant. Mineral-based lubricant is highly pollutant and possesses environmental threat as it is not biodegradable, in the initial days of the industrial revolution bio-based lubricants were widely used, later it was replaced by more sustainable and easily available but environmental polluting mineral oils, currently due to environmental concerns and scarcity of mineral oils, bio-based lubricant has gained importance. Bio-based lubricants are now a day’s used for various applications such as transformer oil and processes where there is complete loss of lubricants. They possess very good properties in such applications, whereas bio-based lubricants are also used internal combustion engines, pure biobased lubricant may not be suitable for long-duration, but genetically and chemically modified bio-based lubricants will be suitable for IC engine. Though bio-based lubricant possesses many good properties as a lubricant for IC engine and various other application, it is still at large to become commercial, more study is required for checking performance of such pure and modified bio-based lubricants oils, in this paper such study of cotton seed Trimethylolpropane (TMP) ester oil and its effects on performance of brake specific fuel consumption (BSFC), brake thermal efficiency (BTh) and emission of gases like hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2 ) nitrogen oxides (NOx ) are studied, bio-based have poor cold flow properties and oxidation stability to improve these additives are added. The experimental study shows that Cottonseed Trimethylolpropane Ester (CSTE) displays similar characteristics of thermal efficiency, brake specific fuel consumption and emission of gases as compared to mineralbased lubricating oil hence can be used in the IC engine instead of mineral-based lubricants.

A study on waste transformer oil blended with BD IC engine application

The work examines the study on waste transformer oil as a novel based alternate BD for compression engine. For this purpose different properties of waste transformer oil were determined. To analysis various combustion and emission waste transformer oil are used as the alternate fuel in IC engine. The investigation includes three parts. In the first part of the work transesterification process were conducted. In the next, the refined waste transformer oil is designated in as BD. In the third part of work, different blends like BD100, B10, B20, B30, B40 and D100 is tested in a single cylinder engine to evaluate performance and emission. At the last it concluded that B30 is best among all the blends can be used as an alternate fuel in diesel engine.

Modelling compression ignition engines by incorporation of the flamelet generated manifolds combustion closure

Tabulated chemistry models allow to include detailed chemistry effects at low cost in numerical simulations of reactive flows. Characteristics of the reactive fluid flows are described by a reduced set of parameters that are representative of the flame structure at small scales so-called flamelets. For a specific turbulent combustion configuration, flamelet combustion closure, with proper formulation of the flame structure can be applied. In this study, flamelet generated manifolds (FGM) combustion closure with progress variable approach were incorporated with OpenFOAM® source code to model combustion within compression ignition engines. For IC engine applications, multi-dimensional flamelet look-up tables for counter flow diffusive flame configuration were generated. Source terms of non-premixed combustion configuration in flamelet domain were tabulated based on pressure, temperature of unburned mixture, mixture fraction, and progress variable. A new frozen flamelet method was introduced to link one dimensional reaction diffusion space to multi-dimensional Computational Fluid Dynamics (CFD) physical space to fulfill correct modelling of thermal state of the engine at expansion stroke when charge composition was changed after combustion and reaction rates were subsided. Predictability of the developed numerical framework were evaluated for Sandia Spray A (constant volume vessel), Spray B (light duty optical Diesel engine), and a heavy duty Diesel engine experiments under Reynolds averaged Navier Stokes turbulence formulation. Results showed that application of multi-dimensional FGM combustion closure can comprehensively predict key parameters such as: ignition delay, in-cylinder pressure, apparent heat release rate, flame lift-off , and flame structure in Diesel engines.

A statistical analysis on tar reduction in producer gas for IC engine application

ABSTRACT The automobile sector attained a boom in the last decade; this made the necessity for more fuel consumption. To meet the demand, many alternate fuel systems are introduced. Among that, producer gas blend carbonated fuels are highly recommended. Since, it is adaptive to the current internal combustion engines with modified carburetor. This paper aims to investigate the production of producer gas from wood and the methods to filter the tar content in it. The chemical-catalytic method is the cost- and eco-effective way to reduce the tar in producer gas. Therefore, a new Ni-based TiO2-supported catalysts are synthesised to improve the efficiency of the tar cracking. The catalytic system is affected by other factors such as bed temperature, catalyst weight, gas feed rate and gas residence time (GRT). The design of experiments is framed with L27 design table and the response is optimised using the Taguchi methodology. The derived regression equation attained 98.4% of adequacy in response prediction and the identified optimaltar cracking efficiency is 99.46% for Ni-Pr/TiO2 catalyst.

Optical investigation of the interaction of an automotive spray and thin films by utilization of a high-pressure spin coater

Although the interaction of automotive sprays with thin films is of high technical relevance for IC engine applications, fundamental knowledge about underlying physical mechanisms is still limited. This work presents a systematic study of the influence of the film’s initial thickness—homogeneously spread over a flat wall before the initial spray impingement—on film surface structures and thickness after the interaction. For this purpose, interferometric film thickness measurements and complementary high-speed visualizations are used. By gradually increasing the initial film thickness on a micrometer scale, a shift from a regime of liquid deposition (increasing film thickness with respect to initial film thickness) to a regime of liquid removal (decreasing film thickness with respect to initial film thickness) is observed at the stagnation zone of the impinging spray. This transition is accompanied by the formation of radially propagating surface waves, transporting liquid away from the stagnation zone. Wavelengths and amplitudes of the surface waves are increased with increasing initial film thickness.

Effect of Parallel Computing Environment on the Solution Consistency of CFD Simulations—Focused on IC Engines

For CFD results to be useful in IC engine analysis, simulation results should be accurate and consistent. However, with wide spread use of parallel computing nowadays, it has been reported that a model would not give the same results against the same input when the parallel computing environment is changed. The effect of parallel environment on simulation results needs to be carefully investigated and understood. In this paper, the solution inconsistency of parallel CFD simulations is investigated. First, the concept of solution inconsistency on parallel computing is reviewed, followed by a systematic CFD simulations specific to IC engine applications. The solution inconsistency against the number of CPU cores was examined using a commercial CFD code CONVERGE. A test matrix was specifically designed to examine the core number effect on engine flow, spray and combustion submodels performance. It was found that the flow field simulation during the gas exchange process is the most sensitive to the number of cores among all submodels examined. An engineering solution was developed where local upwind scheme was used to control the variability, which showed good performance. The implication of the observed inconsistency was also discussed.

Development and Analysis of Wall Models for Internal Combustion Engine Simulations Using High-speed Micro-PIV Measurements

The performance, efficiency and emissions of internal combustion (IC) engines are affected by the thermo-viscous boundary layer region and heat transfer. Computational models for the prediction of engine performance typically rely on equilibrium wall-function models to overcome the need for resolving the viscous boundary layer structure. The wall shear stress and heat flux are obtained as boundary conditions for the outer flow calculation. However, these equilibrium wall-function models are typically derived by considering canonical flow configurations, introducing substantial modeling assumptions that are not necessarily justified for in-cylinder flows. The objective of this work is to assess the validity of several model approximations that are commonly introduced in the development of wall-function models for IC-engine applications. This examination is performed by considering crank-angle resolved high-resolution micro-particle image velocimetry (µ-PIV) measurements in a spark-ignition direct-injection single cylinder engine. Using these measurements, the performance of an algebraic equilibrium wall-function model commonly used in RANS and LES IC-engine simulations is evaluated. By identifying shortcomings of this model, a non-equilibrium differential wall model is developed and two different closures are considered for the determination of the turbulent viscosity. It is shown that both wall models provide adequate predictions if applied inside the viscous sublayer. However, the equilibrium wall-function model consistently underpredicts the shear stress if applied in the log-layer. In contrast, the non-equilibrium wall model provides improved predictions of the near-wall region and shear stress irrespective of the wall distance and the piston location. By utilizing the experimental data, significant adverse pressure gradients due to the large vortical motion inside the cylinder (induced by tumble, swirl and turbulence) are observed and included in the non-equilibrium wall model to further improve the model performance. These investigations are complemented by developing a consistent wall heat transfer model, and simulation results are compared against the equilibrium wall-function model and Woschni’s empirical correlation.

Prediction of tar and particulate in biomass gasification using adaptive neuro fuzzy inference system

Biomass is an important primary source of renewable energy source. Producer gas, a derivative of Biomass, comprises of tar and particulate content which is harmful and critical parameter for IC engine application, which influences the design of filter. Numerous researchers have developed various types of filter for gas cleaning system in order to reduce the tar content and particulate in producer gas. In this work, an experimental investigation has been carried out on the newly developed hybrid compact filter using two different feeds such as rice husk and wood. The experimental results obtained were used to justify the newly developed system with adaptive neuro-fuzzy inference system(ANFIS). The data has been collected taken from an experimental database of a 20 kW open core downdraft TNAU(Tamil Nadu Agricultural University)-modified gasifier with compact hybrid filter system. A comparison between the predictions of ANFIS model with other available model in literature is presented. The ANFIS results reveal that the model delivers the tar and particulate content with an accuracy of 99.98%. The test results prove the possibility to develop and evaluate an ANFIS based model to predict tar content and particulate for any filter design under varying input conditions.

Development and Validation of Reaction Mechanisms for Alcohol-Blended Fuels for IC Engine Applications

Advanced numerical models have been developed for better understanding of how adding mixed alcohol fuels to stock fuels affects octane number and emissions. For predictions of combustion and emissions, a reduced chemical kinetic mechanism has been developed for fuel mixtures with components including isooctane, n-heptane, methanol, ethanol, n-butanol, and propanol. The model predictions show a boosted octane number with the addition of alcohols and reduced emissions of both carbon monoxide (CO) and nitrogen oxides (NOx). The numerically predicted trends are consistent with experimental data from the Cooperative Fuel Research (CFR) single-cylinder engine, and the reduced chemistry can be readily implemented into 3-D simulations.

Estimating IC engine exhaust gas lambda and oxygen from the response of a universal exhaust gas oxygen sensor

Universal exhaust gas oxygen sensors (UEGOs) are in widespread use in internal combustion engines where they are used to measure lambda (the non-dimensional air–fuel ratio) and oxygen concentration (). The sensors are used on production engines and for research and development. In a previous paper, a model of the UEGO sensor was presented, based on a solution of the Stefan–Maxwell equations for an axisymmetric geometry, and it was shown that for a known gas composition, predictions of the sensor response agreed well with experiment. In the present paper, the more ‘practical’ problem is addressed: how well can such a model predict λ and based on the sensor response? For IC engine applications, a chemistry model is required in order to predict λ, and such a model is also desirable for an accurate prediction of . A fast (matrix exponential) method of solving the Stefan–Maxwell equations is also introduced, which offers the possibility of a near real-time computation of λ and , with application, for example, to bench instruments. Extensive results are presented showing how the interpretation of the UEGO response may be compromised by uncertainties. These uncertainties may relate not only to the sensor itself, such as temperature, pressure and mean pore diameter, but also the chemistry model.

A Review on Atomization and Sprays of Biofuels for IC Engine Applications

Ever increasing energy requirements, environmental concerns and energy security needs are strongly influencing engine researchers to consider renewable biofuels as alternatives to fossil fuels. Spray process being important in IC engine combustion, existing literature on various biofuel sprays is reviewed and summarized. Both experimental and computational research findings are reviewed in a detailed manner for compression ignition (CI) engine sprays and briefly for spark ignition (SI) engine sprays. The physics of basic atomization process of sprays from various injectors is included to highlight the most recent research findings followed by discussion highlighting the effect of physico-chemical properties on spray atomization for both biofuels and fossil fuels. Biodiesel sprays are found to penetrate faster and have narrow spray plume angle and larger droplet sizes compared to diesel. Results of analytical and computational models are shown to be useful in shedding light on the actual process of atomization. However, further studies on understanding primary atomization and the effect of fuel properties on primary atomization are required. As far as secondary atomization is concerned, changes in regimes are observed to occur at higher air-jet velocities for biodiesel compared to those of diesel. Evaporating sprays revealed that the liquid length is longer for biodiesel. Pure plant oil sprays with potential use in CI engines may require alternative injector technology due to slower breakup as compared to diesel. Application of ethanol to gasoline engines may be feasible without any modifications to port fuel injection (PFI) engines. More studies are required on the application of alternative fuels to high pressure sprays used in Gasoline Direct Injection (GDI) engines.

GC-MS determination of low hydrocarbon species (C 1–C 6) from a diesel partial oxidation reformer

The partial oxidation (PO x) reforming of Ultra Low Sulphur-Diesel (ULSD), rapeseed methyl ester (RME) - biodiesel and Fischer–Tropsch synthetic diesel fuels (SD) were studied by using a fixed-bed reactor. The ease of reforming the three fuels was first examined at different O/C feed ratios at constant gas hourly space velocity (GHSV) of 35 k h −1 over a prototype monolith catalyst (1%Rh/CeO 2–ZrO 2). The hydrocarbon species (C 1–C 6) produced in the reformer were analyzed using direct gas injection gas chromatography mass spectrometry (GC-MS). Under the same O/C ratios for 35 k h −1 the fuels conversion and process efficiency was dependent on the fuel type, and followed the general trend: SD > biodiesel > ULSD. The GC-MS analysis shows that both, biodiesel and ULSD diesel produced significantly higher amounts of alkenes compared to SD fuel. Fuel with relatively high aromatics content such diesel can be efficiently reformed to syngas over the catalyst used in this study but the reformer operating range (e.g. O/C ratio and space velocity) is limited compared to paraffinic fuels such as FT-SD. At increased GHSV of 45 k h −1 and O/C = 1.75, the diesel fuel conversion efficiency to syngas (H 2 and CO) was improved significantly and the formation of intermediate species such as methane, ethylene, and propylene was reduced considerably as a result of the increased peak reaction temperatures. The reduced HC species and increased H 2 concentration in the reactor product gas from the reforming of FT-SD fuel can provide significant advantages to the IC engine applications.

Gas cleaning for IC engine applications from fixed bed biomass gasification

Biodiesels have received increasing attention as alternative fuels for diesel engines and generators. This study investigates the emissions of particulate matter (PM), total carbon (TC), e.g., organic/elemental carbons, and polycyclic aromatic hydrocarbons (PAHs) from a diesel generator fuelled with soy-biodiesel blends. Among the tested diesel blends (B0, B10 (10 vol% soy-biodiesel), B20, and B50), B20 exhibited the lowest PM emission concentration despite the loads (except the 5 kW case), whereas B10 displayed lower PM emission factors when operating at 0 and 10 kW than the other fuel blends. The emission concentrations or factors of EC, OC, and TC were the lowest when B10 or B20 was used regardless of the loading. Under all tested loads, the average concentrations of total-PAHs emitted from the generator using the B10 and B20 were lower (by 38% and 28%, respectively) than those using pure petroleum diesel fuel (B0), while the emission factors of total-PAHs decreased with an increasing ratio of biodiesel to premium diesel. With an increasing loading, although the brake specific fuel consumption decreased, the energy efficiency increased despite the bio/petroleum diesel ratio. Therefore, soy-biodiesel is promising for use as an alternative fuel for diesel generators to increase energy efficiency and reduce the PM, carbon, and PAH emissions.

Gas cleaning for IC engine applications from fixed bed biomass gasification

Gas cleaning for IC engine applications from fixed bed biomass gasification