The effect of biodiesel oxidation on engine performance and emissions

Biodiesel is a fuel consisting of the alkyl monoesters of vegetable oils or animal fats. Biodiesel is nontoxic, renewable, and biodegradable. Biodiesel-fueled engines produce less carbon monoxide, unburned hydrocarbon, and particulate emissions than diesel fueled engines. One drawback of biodiesel is that it is susceptible to oxidation which can induce polymerization of the esters and can form insoluble gums and sediments which are known to cause fuel filter plugging. However, no research has been conducted to determine the impact of oxidized biodiesel on engine emissions and fuel system performance;The objective of this study was to relate the chemical and physical processes associated with biodiesel oxidation to the conditions that affect engine performance and emissions. In addition, a relationship was sought between ASTM D2274, a diesel fuel-based stability test and AOCS Cd 8-53 and Cd 3a-63 which characterize the chemical changes in the fuel;It was expected that the fuel filters would plug as the vegetable oil esters oxidized but no filter plugging was observed in this study even when the fuel oxidized beyond the level that would be encountered in practice. Recent research by others has suggested that the filter plugging may be associated with reactions between the diesel fuel additives and biodiesel;The engine performance of the oxidized biodiesel was similar to that of No. 2 diesel fuel with nearly the same thermal efficiency, and slightly higher fuel consumption. Oxidized biodiesels produced between 14% and 16% lower CO and HC emissions and smoke number compared to unoxidized biodiesel. No statistically significant difference was found between the NOx emissions from oxidized biodiesel and unoxidized biodiesel. Oxidized biodiesel experienced a one degree shorter ignition delay than unoxidized biodiesel. The ignition delay was almost linearly correlated to CO and HC emissions. A common linear relationship was found between the start of combustion and the NOx emissions. When the NOx was plotted against the start of combustion timing, the neat biodiesel produced lower NO x emissions than the No. 2 diesel fuel

Impact of biodiesel fuel on cold starting of automotive direct injection diesel engines

The use of biodiesel fuels in diesel engines is gaining attention as a promising solution to control CO2 emissions. Great research efforts have been carried out to identify the impact of biodiesel physical and chemical properties on engine systems and processes. Most of these investigations were performed in warm conditions, but the suitability of biodiesel for starting the engine at under-zero ambient temperatures has not widely evaluated. The surface tension and the viscosity of biodiesel fuels are higher compared to those of standard diesel and, in cold conditions, these differences become critical since the injection fuel rate is largely affected and consequently the combustion process can be deteriorated. In order to improve its flow characteristics at cold temperatures and make them more suitable for low temperatures operation, additives are used in biodiesel fuels. In this paper the suitability of different biodiesel fuels, with and without additives, for cold starting of DI (direct injection) diesel engines has been evaluated. The results have shown that the engine start-ability with pure biodiesel fuels can be largely deteriorated. However, using diesel/biodiesel blends the start-ability of the engine can be recovered with the additional benefit of reducing the opacity peak of the exhaust gasesBroatch Jacobi, JA.; Tormos Martínez, BV.; Olmeda González, PC.; Novella Rosa, R. (2014). Impact of biodiesel fuel on cold starting of automotive direct injection diesel engines. Energy. 73:653-660. doi:10.1016/j.energy.2014.06.062S6536607

Characteristics of LPG-diesel dual fuelled engine operated with rapeseed methyl ester and gas-to-liquid diesel fuels

AbstractA Liquefied Petroleum Gas (LPG)-diesel dual fuelled combustion experimental study was carried out to understand the impact of the properties of the direct injection diesel fuels, such as rapeseed methyl ester (RME) and gas-to-liquid (GTL), on combustion characteristics, engine performance and emissions. The experimental results showed that up to 60% of liquid fuel replacement by LPG was reached while keeping engine combustion variability within the acceptable range and obtaining clear benefits in the soot-NOx trade-off. However, the amount of LPG was limited by adverse effects in engine thermal efficiency, HC and CO emissions. LPG–RME showed a good alternative to LPG-diesel dual fuelling, as better engine combustion variability, HC, CO and soot behaviour was obtained when compared to the other liquid fuels, mainly due to its fuel oxygen content. On the other hand, NOx emissions were the highest, but these can be balanced by the application of EGR. LPG–GTL dual fuelling resulted in the highest NOx emissions benefit over a wide range of engine operating conditions. The high cetane number and the absence of aromatic of GTL are the main parameters for the more favourable soot-NOx trade-off compared to LPG–ULSD (ultra low sulphur diesel) dual fuelling

Impact of Fischer Tropsch and biodiesel fuels on trade-offs between pollutant emissions and combustion noise in diesel engines

[EN] Over recent decades, direct injection diesel engines have become the propulsion systems most commonly used in automotive vehicles in Europe. Their leading position in the European market is due to improvements in performance, driveability and their capacity for facing the increasingly restrictive standards to which are subject. Nevertheless, their main drawbacks are related to the emission levels, the use of fossil fuels and the engine noise. To mitigate the first two problems, alternative fuels are being used in these engines with encouraging results. The impact of these fuels on engine noise might therefore be analyzed in order to evaluate the feasibility of such a solution. In this work the effect of diverse alternative fuels on emissions, performance and engine noise quality was analyzed. Compared with standard diesel fuel, results show a scarce variation of combustion noise quality whereas soot level decreases, NOx emissions increase and specific consumption deteriorates. (C) 2013 Elsevier Ltd. All rights reserved.This work has been partially supported by Ministerio de Educacion y Ciencia through grant No. TRA2006-13782. L.F. Monico holds the grant 2009/003 from Santiago Grisolia Program of Generalitat Valenciana.Torregrosa, AJ.; Broatch, A.; Plá Moreno, B.; Mónico Muñoz, LF. (2013). Impact of Fischer Tropsch and biodiesel fuels on trade-offs between pollutant emissions and combustion noise in diesel engines. Biomass and Bioenergy. 52:22-33. https://doi.org/10.1016/j.biombioe.2013.03.004S22335

Microscopic characteristics of biodiesel – Graphene oxide nanoparticle blends and their Utilisation in a compression ignition engine

Use of nano-additives in biofuels is an important research and development topic for achieving optimum engine performance with reduced emissions. In this study, rice bran oil was converted into biodiesel and graphene oxide (GO) nanoparticles were infused into biodiesel-diesel blends. Two blends containing (i) 5% biodiesel, 95% diesel and 30 ppm GO (B5D95GO30) and (ii) 15% biodiesel, 85% diesel and 30 ppm GO (B15D85GO30) were prepared. The fuel properties like heating value, kinematic viscosity, cetane number, etc. of the nanoadditives–biodiesel-diesel blends (NBDB) were measured. Effects of injection timing (IT) on the performance, combustion and emission characteristics were studied. It was observed that both B15D85GO30 and B5D95GO30 blends at IT23° gave up to 13.5% reduction in specific fuel consumption. Compared to diesel, the brake thermal efficiency was increased by 7.62% for B15D85GO30 at IT23° and IT25°. An increase in IT from 23° to 25° deteriorated the indicated thermal efficiency by 6.68% for B15D85GO30. At maximum load condition, the peak heat release rates of NBDB were found to be lower than the pure diesel at both IT. The CO, CO2 & NOx emissions were reduced by 2–8%. The study concluded that B15D85GO30 at IT23° gave optimum results in terms of performance, combustion and emission characteristics

The effect of biodiesel oxidation on engine performance and emissions

Biodiesel is a fuel consisting of the alkyl monoesters of vegetable oils or animal fats. Biodiesel is nontoxic, renewable, and biodegradable. Biodiesel-fueled engines produce less carbon monoxide, unburned hydrocarbon, and particulate emissions than diesel fueled engines. One drawback of biodiesel is that it is susceptible to oxidation which can induce polymerization of the esters and can form insoluble gums and sediments which are known to cause fuel filter plugging. However, no research has been conducted to determine the impact of oxidized biodiesel on engine emissions and fuel system performance;The objective of this study was to relate the chemical and physical processes associated with biodiesel oxidation to the conditions that affect engine performance and emissions. In addition, a relationship was sought between ASTM D2274, a diesel fuel-based stability test and AOCS Cd 8-53 and Cd 3a-63 which characterize the chemical changes in the fuel;It was expected that the fuel filters would plug as the vegetable oil esters oxidized but no filter plugging was observed in this study even when the fuel oxidized beyond the level that would be encountered in practice. Recent research by others has suggested that the filter plugging may be associated with reactions between the diesel fuel additives and biodiesel;The engine performance of the oxidized biodiesel was similar to that of No. 2 diesel fuel with nearly the same thermal efficiency, and slightly higher fuel consumption. Oxidized biodiesels produced between 14% and 16% lower CO and HC emissions and smoke number compared to unoxidized biodiesel. No statistically significant difference was found between the NOx emissions from oxidized biodiesel and unoxidized biodiesel. Oxidized biodiesel experienced a one degree shorter ignition delay than unoxidized biodiesel. The ignition delay was almost linearly correlated to CO and HC emissions. A common linear relationship was found between the start of combustion and the NOx emissions. When the NOx was plotted against the start of combustion timing, the neat biodiesel produced lower NO x emissions than the No. 2 diesel fuel.</p

Emission Characteristics of a CI Engine Running with a Range of Biodiesel Feedstocks

Currently, alternative fuels are being investigated in detail for application in compression ignition (CI) engines resulting in exciting potential opportunities to increase energy security and reduce gas emissions. Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. The objective of this study is to investigate the effects of biodiesel types and biodiesel fraction on the emission characteristics of a CI engine. The experimental work was carried out on a four-cylinder, four-stroke, direct injection (DI) and turbocharged diesel engine by using biodiesel made from waste oil, rapeseed oil, corn oil and comparing them to normal diesel. The fuels used in the analyses are B10, B20, B50, B100 and neat diesel. The engine was operated over a range of engine speeds. Based on the measured parameters, detailed analyses were carried out on major regulated emissions such as NOx, CO, CO2, and THC. It has been seen that the biodiesel types (sources) do not result in any significant differences in emissions. The results also clearly indicate that the engine running with biodiesel and blends have higher NOx emission by up to 20%. However, the emissions of the CI engine running on neat biodiesel (B100) were reduced by up to 15%, 40% and 30% for CO, CO2 and THC emissions respectively, as compared to diesel fuel at various operating conditions