Biodiesel Combustion Research Articles

Effects of pilot injection strategies on the flame temperature and soot distributions in an optical CI engine fueled with biodiesel and conventional diesel

Among the many types of alternative fuels, biodiesel has emerged as an eco-friendly fuel for the compression-ignition engines. Investigations into biodiesel combustion have been performed with various aspects and methodologies. In this study, the effects of the pilot injection strategies on the flame temperature and soot distribution were investigated experimentally and numerically using an optical CI engine fueled with biodiesel. The endoscopy system captured the spray development and combustion processes in the cylinder. In addition, obtained pictures were used to estimate the flame temperature and soot distribution using a post-processing program. Furthermore, the KIVA/CHEMKIN code was used to enhance the analysis of the pilot combustion characteristics. These numerical results allowed information that cannot be obtained from physical experiments. The experimental conditions were composed of various pilot injection timings and quantities. In the present experiment, the experimental conditions were fixed with the exception of the injection strategy that was used. The experimental results showed that the flame temperature decreased as the pilot fuel mass increased. Additionally, it was also found that biodiesel combustion generated a higher flame temperature and lower soot concentrations compared to neat diesel combustion.

Characterization and Reduction of NO during the Combustion of Biodiesel in a Semi-industrial Boiler

This paper aims to characterize and reduce the level of nitrogen monoxide (NO) during the combustion of rapeseed oil methyl ester (ROME) in a semi-industrial boiler. First, the formation of NO is characterized during transitional and steady-state operation of boiler; the influence of combustion pressure, excess air, exhaust gas temperature, spray cone angle, and combustion air swirl angle on the level of NO is evaluated, suitable burner operating points for control of NO are recognized, and contributions of thermal and prompt NO to the total level of NO are obtained. At the next level, the potential of air-staging technique (injection of extra air) in the reduction of NO is studied. Results reveal that the level of NO rises significantly in the post-flame zone 10 cm after the tail of the flame, where only the formation of thermal NO is probable in the chamber. Staged air is able to reduce the level of NO up to 10% without any negative impact on the operation of the boiler. Results also reveal that fuel sp...

Comparative electrocardiographic, autonomic and systemic inflammatory responses to soy biodiesel and petroleum diesel emissions in rats

Context: Biodiesel fuel represents an alternative to high particulate matter (PM)-emitting petroleum-based diesel fuels, yet uncertainty remains regarding potential biodiesel combustion emission health impacts.Objective: The purpose of this study was to compare cardiovascular responses to pure and blended biodiesel fuel emissions relative to petroleum diesel exhaust (DE).Materials and methods: Spontaneously hypertensive rats were exposed for 4 h per day for four days via whole body inhalation to combustion emissions (based on PM concentrations 50, 150 or 500 μg/m3 or filtered air) from pure (B100) or blended (B20) soy biodiesel, or to pure petroleum DE (B0). Electrocardiogram (ECG) and heart rate variability (HRV, an index of autonomic balance) were monitored before, during and after exposure while pulmonary and systemic inflammation were assessed one day after the final exposure. ECG and HRV data and inflammatory data were statistically analyzed using a linear mixed model for repeated measures and an analysis of variance, respectively.Results: B100 and B0, but not B20, increased HRV during all exposure days at the highest concentration indicating increased parasympathetic tone. Electrocardiographic data were mixed. B100 and B0, but not B20, caused significant changes in one or more of the following: serum C-reactive protein, total protein, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol, and blood urea nitrogen (BUN) and plasma angiotensin converting enzyme (ACE) and fibrinogen.Discussion and conclusions: Although responses to emissions from all fuels were mixed and relatively mild, some findings point to a reduced cardiovascular impact of blended biodiesel fuel emissions.

NOx emissions from low-temperature combustion of biodiesel made of various feedstocks and blends

Nitrogen oxides (NOx) are one of the major hazardous emissions from biodiesel-fueled engines that need to be regulated stringently. In this paper, NOx emissions from different types of biodiesel were studied using a laboratory combustion chamber. Biodiesel fuels with various portion of fatty acid methyl esters (FAMEs) from soybean methyl ester (SME), tallow oil (TO), and waste cooking oil (WCO) were combusted at 330–420°C simulating low-temperature combustion (LTC). Combustion analysis results show that neat biodiesel fuels had longer ignition delay and lower ignition temperatures compared to ultra-low sulfur diesel (ULSD). The unsaturation of biodiesel samples and their blends with ULSD was analyzed for its effects on NOx emissions. The results showed that biodiesel with more unsaturated fatty acids emitted more NOx compared to biodiesel with more saturated fatty acids. A paired t-test showed that neat TO, WCO, and WCO B50 had significant reduction in the formation of NOx compared with ULSD and SME B20. It is concluded that less unsaturated FAME fuels would be preferable when reduction of NOx emissions is a critical issue.

A Review on Microalgae Biodiesel Production and its Usage in Direct Injection Diesel Engines as Alternate Fuel

Biodiesel is one of the promising alternative fuels for automotive engines due to the depletion of fossil fuel resources, increasing energy demands and environmental concerns. The biodiesel can be obtained from various bio energy resources such as edible and non-edible vegetable oils and animal fats. However, the use of biodiesel derived from edible oils such as palm oil, sunflower oil and soybean oil has negative impact on global food market. Biodiesel from microalgae is considered as a third generation biofuel derived from non-edible resources and best suited for internal combustion engines. Microalgae have the potential to provide sufficient fuel for global consumption due to its high oil content and fast growing ability. This paper provides a brief overview of biodiesel production from microalgae biomass and its suitability as alternate fuel in diesel engines. This review highlights the selection of suitable algae species for oil production, fuel properties in comparison with standard diesel and other biodiesel fuels, performance, combustion and emission characteristics when used in engines, and the economical aspects. Further, the research and development aspects of biodiesel from microalgae as fuel for automobile diesel engines are also reviewed.

Engine Emissions and Performance using WCO Biodiesel

Combustion performance and exhaust emissions from the combustion of biodiesel made from waste cooking oil (WCO) are presented in this paper. Several solutions for alternative fuels particularly to substitute petroleum/fossil fuels in transport sector are available. Waste cooking oil (WCO) is one such option already used in certain ratios in the US, EU and other countries but there are still some issues relating to running diesel engines on WCO due to differences in the chemical composition between biodiesel and diesel. In order to gather more information of the overall performance in engines and emission formation, experimental tests were conducted and comparisons were made with the petroleum diesel. Elemental analysis of WCO biodiesel confirmed that different functional groups, lead to major differences in the combustion characteristics of the two fuel types. The biodiesel found to have 10% lower carbon content, almost no Sulphur content and up to 12%, more oxygen content compared with diesel. Higher oxygen content and double bonds in WCO biodiesel increase its susceptibility to oxidation and explains up to l8% lower caloric value and up to 9% lower engine torque compared with diesel. Using WCO blends ratio up to 75% in diesel showed a reduction in exhaust emissions compared with diesel. The brake specific fuel consumption (BSFC) increases as the biodiesel blend ratio in diesel increases due to greater mass of fuel being injected at a given injection pressure, compared with diesel. A common conclusion can be made in favor of the WCO biodiesel as being a greener alternative to petro-diesel when used in blend with diesel. Large variations in the feedstock used for biodiesel production would lead to variations in the physical and chemical properties of the WCO biodiesel produced. Stringent standards may need to be imposed for biodiesel quality in order to reduce the effect of variation in physiochemical properties on engine performance and emissions. However, experimental tests confirmed that biodiesel-diesel blends could be used in current diesel engines without loss of performance.

Modeling of Common Rail System and Constant Volume Chamber in Biodiesel Combustion: A Review

Among the challenges faced by diesel engines combustion nowadays are to reduce emission especially Nitrogen Oxide (NOx) and Particular Matter (PM) while enhancing fuel efficiency and power. The purpose of this review is to explore the mixture formation of biodiesel combustion using constant volume chamber and optical visualization. This paper will review the development of a single-shot combustion system and constant volume chamber. An overview of the relation of mixture formation and combustion process in diesel combustion is provided first. This review has shown that the application of Rapid compression Machine (RCM) is used to simulate actual condition especially the injection pressure and air motion. The review also found that the mixing between fuel and air is unavoidable and very important during ignition delay period thus predominantly influences the exhaust emission. The detailed behaviour of injection characteristic that strongly effects the mixture formation especially the spray evaporation and spray interference are discussed.Keywords: Rapid Compression Machine; Ignition Delay; Nozzle; Injection System; Air Motion; Ambient

Effects of Temperature and Ambient Pressure on Spray Characteristics of Biodiesel Combustion

s: Diesel fuel injection is the most dominant in ignition process of the diesel engines combustion. Diesel engines have been widely used in heavy-duty and light-duty vehicles due to their higher fuel economy, efficient and powerful than spark ignition (SI) engines. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of mixture formation such as spray penetration, fuel evaporation and spray interference. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapour phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the wall chamber temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air premixing.

A Review Paper on Simulation and Modeling of Combustion Characteristics under High Ambient and High Injection of Biodiesel Combustion

This paper describes simulation of combustion characteristics under high ambient and high injection of biodiesel combustion by using CFD simulation. Diesel engine performance and emissions is strongly couple with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of spray pattern, liquid length and vapor penetration. The method of the simulation of real phenomenon of diesel combustion with optical access rapid compression machine is also reviewed and experimental results are presented. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapor phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing. All of the experiments will be conducted and run by using CFD. The simulation will show in the form of images.

Thermal characterization and model-free kinetics of biodiesel sample

In this study, combustion and pyrolysis behaviours of methanol route biodiesel were investigated using thermal analysis techniques known as simultaneous thermogravimetry and differential scanning calorimetry (DSC) at different heating rates. Reaction regions, peak temperatures, mass loss and heat flow rates of the biodiesel sample are determined using TG-DTG and DSC data. It was found that as the heating rate of the reactions increased, peak temperatures of the reactions shifted higher temperatures, implying that as the heating rate of the reactions increased, reaction lost their sensitivity. Two different model-free kinetic methods, known as Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose, as proposed by ICTAC kinetics committee, were applied to determine the pyrolysis and combustion reaction parameters of biodiesel sample, and the results are discussed.

Modeling analysis of urea direct injection on the NOx emission reduction of biodiesel fueled diesel engines

In this paper, a numerical simulation study was conducted to explore the possibility of an alternative approach: direct aqueous urea solution injection on the reduction of NOx emissions of a biodiesel fueled diesel engine. Simulation studies were performed using the 3D CFD simulation software KIVA4 coupled with CHEMKIN II code for pure biodiesel combustion under realistic engine operating conditions of 2400rpm and 100% load. The chemical behaviors of the NOx formation and urea/NOx interaction processes were modeled by a modified extended Zeldovich mechanism and urea/NO interaction sub-mechanism. To ensure an efficient NOx reduction process, various aqueous urea injection strategies in terms of post injection timing, injection angle, and injection rate and urea mass fraction were carefully examined. The simulation results revealed that among all the four post injection timings (10°ATDC, 15°ATDC, 20°ATDC and 25°ATDC) that were evaluated, 15°ATDC post injection timing consistently demonstrated a lower NO emission level. The orientation of the aqueous urea injection was also shown to play a critical role in determining the NOx removal efficiency, and 50 degrees injection angle was determined to be the optimal injection orientation which gave the most NOx reduction. In addition, both the urea/water ratio and aqueous urea injection rate demonstrated important roles which affected the thermal decomposition of urea into ammonia and the subsequent NOx removal process, and it was suggested that 50% urea mass fraction and 40% injection rate presented the lowest NO emission levels. At last, with the optimized injection strategy, the engine presented significantly reduced NO emission from 131ppm to 55ppm compared to the case of pure biodiesel combustion, achieving a reduction efficiency of 58%, suggesting that urea direct injection could be an effective method to reduce the NOx emissions of a biodiesel fueled diesel engine.

Oxygenated palm biodiesel: Ignition, combustion and emissions quantification in a light-duty diesel engine

This paper presents an investigation of oxygenated neat palm biodiesel in a direct injection single cylinder diesel engine in terms of ignition, combustion and emissions characteristics. Conventional non-oxygenated diesel fuel is compared as baseline. The engine testing is performed between the operating speed of 2000–3000rpm and load of up to 3bar of brake mean effective pressure. From it, a total of 50 experiment cases are tested to form a comprehensive operational speed-load contour map for ignition and combustion; while various engine-out emissions such as NO, CO, UHCs and CO2 are compared based on fuel type-speed combinations. The ignition and combustion evolution contour maps quantify the absolute ignition delay period and elucidate the difference between that of palm biodiesel and fossil diesel. Although diesel has shorter ignition delay period by up to 0.6 CAD at 3000rpm and burns more rapidly at the start of combustion, combustion of palm biodiesel accelerates during the mid-combustion phase and overtakes diesel in the cumulative heat release rates (HRR) prior to the 90% cumulative HRR. This can be attributed to the oxygen contained in palm biodiesel assisting in localized regions of combustion. In terms of performance, the oxygenated nature of palm biodiesel provided mixed performances with improved thermal efficiency and increased brake specific fuel consumption, due to the improved combustion and lower calorific values, respectively. Emission measurements show that NO for palm biodiesel is lower compared to diesel at low and mid operating speed by up to 36.8%, which can be attributed to the lower combustion temperature. Other emissions such as CO, UHCs and CO2 showed similar emissions output for the two fuels. The prevailing trends from this study is also compared against trends from other similar studies to form a definitive trend guide for the performance and emissions parameters of interest for light-duty diesel engines when fuelled with biodiesel.

Spray and combustion of waste cooking oil biodiesel in a compression-ignition engine

An experimental study was carried out to compare the spray and combustion characteristics of waste cooking oil biodiesel with those of conventional diesel in a common-rail direct-injection compression-ignition engine. The indicated mean effective pressure of approximately 0.7 MPa was tested under an engine speed of 800 r/min. The fuels were injected at an injection timing of −5 crank angle degree after top dead center with injection pressures of 80 and 160 MPa. The experiments were performed to investigate the combustion and emission characteristics in a metal engine, while spray and combustion flame characteristics in an optical engine. The morphological and compositional features of particulate matter were also analyzed by using transmission electron microscopy and thermogravimetric analysis. The direct imaging of the spray indicated a longer injection delay for waste cooking oil biodiesel. However, it exhibited longer liquid penetration length and narrower spray angle than diesel as the spray developed. Waste cooking oil biodiesel combustion showed a longer ignition delay with a slightly lower peak of in-cylinder pressure and heat release rate than diesel due to the deteriorated atomization and evaporation of fuel spray. In terms of emission, waste cooking oil biodiesel showed benefits in reduction of carbon monoxide, unburned hydrocarbon and particulate matter emissions. The particulate matter from waste cooking oil biodiesel was composed of smaller primary particles and more volatile organic fraction than diesel soot. The combustion flame imaging verified the retarded combustion phase of waste cooking oil biodiesel. Waste cooking oil biodiesel combustion showed lower flame luminosity accompanied by shorter visible flame duration, at both injection pressures. The flame spatial fluctuation and flame nonhomogeneity were also lower for waste cooking oil biodiesel.

Using waste animal fat based biodiesels–bioethanol–diesel fuel blends in a DI diesel engine

Abstract In this study, animal fat based biodiesels produced in the pilot plant were blended with certain amounts of diesel fuel and bioethanol. Neat biodiesels, diesel fuel and the blends were tested in a direct injection diesel engine and engine performance, combustion and exhaust emission characteristics were investigated. Engine tests were conducted at constant engine speed (1400 rpm) and four different engine loads (150 Nm, 300 Nm, 450 Nm and 600 Nm). The engine tests showed that the brake specific fuel consumptions (BSFC) of biodiesels were about 16% higher while those of the blends containing 20% bioethanol were about 15.7% higher than those of diesel fuel on average. The maximum cylinder gas pressures of biodiesels were about 1.2% higher than those of diesel fuel on average. The start of combustion of biodiesels occurred at earlier crank angles compared to diesel fuel, while the start of combustion occurred at later crank angles with increasing bioethanol amount in the fuel blends. According to brake specific emission results, biodiesels emitted lower carbon monoxide (CO) emissions but they emit higher carbon dioxide (CO 2 ) and oxides of nitrogen (NO x ) emissions as compared to diesel fuel. THC emissions increased and CO 2 emissions reduced slightly for the blends containing bioethanol compared with B20 (20% biodiesel, 80% diesel fuel) on average.

Caracterización y perfil lipídico de aceites de microalgas

<p>El uso creciente del biodiésel ha impulsado la búsqueda de nuevas materias primas, dentro de las que se destacan las microalgas. En esta investigación se estudió el cultivo de las microalgas Chlorella sp. y Dunaliella salina bajo diferentes condiciones de pH y concentración de nitrógeno (mgL-1), y la caracterización de los aceites obtenidos, con el fin de evaluar su potencial uso como materia prima en la producción de biodiésel. La D. salina alcanzó una máxima concentración celular de 1.15x106 células mL-1 en 6 días de cultivo en unas condiciones de 8.5 pH y 0.1 mg L-1 concentración de nitrógeno, mientras que Chlorella sp. presentó una máxima concentración celular de 2.6x107 células mL-1 en 14 días de cultivo en unas condiciones de 7.5 pH y 0.1 mg L-1 concentración de nitrógeno. La extracción de aceite intracelular de las microalgas cultivadas bajo las mejores condiciones de crecimiento celular se realizó empleando el método modificado de Bligh & Dyer. Al determinar el perfil de ácidos grasos de los aceites extraídos de ambas microalgas, se encontraron en mayor proporción dos ácidos grasos insaturados: ácido linolénico y ácido oleico. En el aceite de D. salina se encontró una concentración de 51% p/p de ácido linolénico, mientras que para el aceite de Chlorella sp. fue de 39% p/p. Con relación al ácido oleico, el aceite de Chrorella sp. presentó una concentración de 35% p/p, superior al aceite de D. salina, con 25% p/p.</p>

Performance and Emission Analysis of a Diesel Engine Burning Biodiesel from Waste Cooking Oil

Biodiesel has a vital role in recent years as an alternative fuel for diesel engines. Biodiesel was produced from waste cooking oil by transesterification process. Physical and chemical properties of biodiesel blends up to 20% were near to diesel fuel. The aim of this study to is to reuse biodiesel produced from waste cooking oil as a fuel and make a comparative study of performance parameters and exhaust emissions between biodiesel blends. Diesel- waste cooking oil biodiesel blends of 10 and 20% were prepared. Experimental investigations were tested in a four stroke, single cylinder, diesel engine at a constant speed of 1500 rpm and variable loads. Diesel- biodiesel blends provided significant increase in fuel consumption, specific fuel consumption, exhaust gas temperature, NOx, CO2 and oxygen concentrations about diesel fuel. Waste cooking oil biodiesel blends resulted in significant decrease in thermal efficiency, volumetric efficiency, air- fuel ratio, CO and HC emissions about diesel fuel. Performance characteristics and exhaust emissions concentrations for biodiesel blends were near to diesel fuel, so, we recommend using biodiesel blends up to 20% in diesel engines without engine modifications.

Accurate prediction of surface tension of biodiesel fuels at different operating conditions using a neuro-fuzzy model

In order to mitigate the environmental pollution and reduce the dependency on the fossil fuel, the biodiesel has been suggested as an alternative fuel in the newly developed diesel engines. Since the surface tension is an important factor for proper atomization and combustion of biodiesels, an adaptive neuro fuzzy inference system (ANFIS) is developed for accurate prediction of the surface tensions of different biodiesels in this work. Comparison of the suggested model with the most important existing models shows that the presented computational framework outperforms the other alternatives both in accuracy and generality. The overall predicted surface tensions regarding ten different biodiesels are in excellent agreement with experimental data with the AAD of 0.43% and R2-value of 0.9865.

Time resolved in-situ biodiesel combustion visualization using engine endoscopy

Optical visualization technique such as engine endoscopy is a very important tool for time resolved spatial combustion visualization and characterization. It provides valuable information about combustion in a production grade engine, which cannot be obtained by using any conventional techniques. In this study, engine endoscopy was done in a single-cylinder; constant speed compression ignition (CI) engine fuelled with diesel and biodiesel blends. A dedicated control circuit was developed to synchronize the camera with in-cylinder combustion events. Combustion images were captured at different engine loads to determine start of combustion (SoC), spatial soot distribution and spatial flame radiation temperatures. With increasing biodiesel content in the fuel, larger area of luminous flames in the combustion images was obtained for lower biodiesel blends (up to B20) however it became smaller for higher biodiesel blends (for B50 and higher). It was also found that the area of soot distribution decreased in later stages of combustion for all test fuels which indicates better oxidation of soot particles. Combustion images showed earlier SoC for biodiesel blends with increasing engine load, which was another important finding of these experiments. Rate of heat release (RoHR) was lower for biodiesel blends compared to mineral diesel. Higher blends of biodiesel showed lower flame radiation temperatures due to soot particles emission that caused lower soot particles volume fraction and higher oxygen content in fuel hence more NOx emission from biodiesel combustion.

Experimental and numerical studies of biodiesel combustion mechanisms using a laminar counterflow spray premixed flame

Biodiesel is a mixture of long chain fatty acids such as methyl esters and is mainly used in diesel engines. Its fundamental properties and combustion pathways still need to be analyzed and validated. The present study concerns the creation and development of new data for the combustion of rapeseed methyl ester biodiesel (RME) and methyl decanoate as a surrogate fuel (MD). Experimental and numerical studies are conducted on a laminar counterflow premixed flame configuration where spray biodiesel/air (or MD/air) is injected against methane/air mixture at atmospheric pressure for different strain rates and equivalence ratio conditions. As chemical schemes for methane/air reactions are enough well known, this configuration is suitable to perform validations of chemical schemes for biodiesel/air (or MD/air) combustion, by taking methane/air flame as a reference. Planar Laser-Induced Fluorescence (PLIF) of OH as well as visible and UV chemiluminescence measurements of the excited radicals CH∗(A2Δ) and OH∗(A2Σ+) are employed to experimentally analyze the biodiesel and MD flame structure. The counterflow spray MD flame is simulated by choosing a skeletal reaction mechanism to which we add CH∗ and OH∗ reactions. In the case of biodiesel flame simulations, a new surrogate kinetics is developed by combining two existing skeletal kinetics schemes. The new scheme guarantees not only a good prediction of measured radicals but also a good methane/air flame speed which is necessary to well predict the flame front position in the counterflow configuration.CH∗ and OH∗ sub-mechanisms are also added to this kinetic scheme. The numerical predictions of the CH∗ concentration are very close to the experimental profiles along the central axis, for both biodiesel and MD kinetic schemes. However the numerical and experimental results show differences in the OH∗ production routes between MD and methane flames.

Chemical Kinetic Influences of Alkyl Chain Structure on the High Pressure and Temperature Oxidation of a Representative Unsaturated Biodiesel: Methyl Nonenoate.

The high pressure and temperature oxidation of methyl trans-2-nonenoate, methyl trans-3-nonenoate, 1-octene, and trans-2-octene are investigated experimentally to probe the influence of the double bond position on the chemical kinetics of long esters and alkenes. Single pulse shock tube experiments are performed in the ranges p = 3.8-6.2 MPa and T = 850-1500 K, with an average reaction time of 2 ms. Gas chromatographic measurements indicate increased reactivity for trans-2-octene compared to 1-octene, whereas both methyl nonenoate isomers have reactivities similar to that of 1-octene. A difference in the yield of stable intermediates is observed for the octenes when compared to the methyl nonenoates. Chemical kinetic models are developed with the aid of the Reaction Mechanism Generator to interpret the experimental results. The models are created using two different base chemistry submodels to investigate the influence of the foundational chemistry (i.e., C0-C4), whereas Monte Carlo simulations are performed to examine the quality of agreement with the experimental results. Significant uncertainties are found in the chemistry of unsaturated esters with the double bonds located close to the ester groups. This work highlights the importance of the foundational chemistry in predictive chemical kinetics of biodiesel combustion at engine relevant conditions.