Direct Injection Diesel Engine Research Articles

Study on the altitude adaptability of single-stage and two-stage turbocharging systems for a heavy-duty diesel engine

It is important to understand the altitude adaptability of the turbocharging system for maximizing its potential in the power recovery of the diesel engine at high altitudes. This study investigated the influence of altitudes ranging from 0 to 4500 m on the performance of the single-stage and two-stage turbocharging systems in a heavy-duty diesel engine. The research was conducted using a six-cylinder, four-stroke, turbocharged, direct-injection diesel engine. An altitude simulation test bench was used to simulate altitudes of 0 to 4500 m by adjusting the temperature and pressure. According to the test results, the altitude adaptability of different turbocharging systems was analyzed based on turbine work and turbocharger efficiency. It was concluded that the high-pressure stage regulation in the two-stage turbocharging system (HRT) strengthens the regulation ability in turbine work, effectively regulating the boost pressure and maintaining high turbocharger efficiency at different altitudes. The HRT can satisfy the regulation ability for altitudes ranging from 0 to 4500 m. The low-pressure stage regulation in the two-stage turbocharging system (LRT) weakens the regulation ability in turbine work and relies on reduction of the turbocharger efficiency to regulate the boost pressure. The LRT ineffectively regulates the boost pressure at low altitudes, with altitude adaptability from 1500 to 4500 m. Due to the exhaust temperature limitation, the waste-gate in the single-stage turbocharging system (WG) is not suitable for large-span regulation to satisfy the performance of the diesel engine at altitudes above 3,000 m compared with the HRT and LRT.

Performance analysis of biofuel-ethanol blends in diesel engine and its validation with computational fluid dynamics.

The engine tests aimed to produce comparable data for fuel consumption, exhaust emissions, and thermal efficiency. The computational fluid dynamics (CFD) program FLUENT was used to simulate the combustion parameters of a direct injection diesel engine. In-cylinder turbulence is controlled using the RNG k-model. The model's conclusions are validated when the projected p-curve is compared to the observed p-curve. The thermal efficiency of the 50E50B blend (50% ethanol, 50% biofuel) is higher than the other blends as well as diesel. Diesel has lower brake thermal efficiency among the other fuel blends used. The 10E90B mix (10% ethanol, 90% biofuel) has a lower brake-specific fuel consumption (BSFC) than other blends but is slightly higher than diesel. The temperature of the exhaust gas rises for all mixtures as the brake power is increased. CO emissions from 50E50B are lower than diesel at low loads but slightly greater at heavy loads. According to the emission graphs, the 50E50B blend produces less HC than diesel. NOx emission rises with increasing load in the exhaust parameter for all mixes. A 50E50B biofuel-ethanol combination achieves the highest brake thermal efficiency, 33.59%. The BSFC for diesel is 0.254 kg/kW-hr at maximum load, while the BSFC for the 10E90B mix is 0.269 kg/kW-hr, higher than diesel. In comparison to diesel, BSFC has increased by 5.90%.

Effect of Plasto-Oil Blended with Diesel Fuel on the Performance and Emission Characteristics of Partly Premixed Charge Compression Ignition Engines with and without Exhaust Gas Recirculation (EGR)

Municipal mixed plastic waste (MMPW) recycling is an innovative way to turn environmental waste into energy fuels. In the present study, a thermochemical process was applied to depolymerize MMPW to produce hydrocarbon fuels known as plasto-oil. The obtained plasto-oil was blended with conventional diesel to test the performance of the PCCI-mode single-cylinder, four-stroke, direct-injection diesel engine. The PCCI combustion mixture was tested with 15% and 30% fuel vapor to ensure homogeneity with and without exhaust gas recirculation. The modified engine findings were compared to a standard conventional engine. At higher loads, PCCI combustion showed reduced emission of carbon monoxide and nitrogen oxides. While the thermal braking efficiency was marginally reduced at all engine loads while using the blends. The results showed that with and without 10% exhaust gas recirculation, an increase in air mix reduced NOx emissions; however, in the case of smoke emissions, an opposite trend was observed. A blend of plasto-oils also decreased CO and unburned hydrocarbon (HC) emissions at higher loads. In conclusion, it was shown that plasto-oils combined with conventional diesel fuel outperformed diesel fuel alone.

How Do Microalgae Biodiesel Blends Affect the Acoustic and Vibration Characteristics of the Direct Injection Diesel Engine: An Experimental Examination

Abstract The noise and vibration characteristics play a vital role in the effectiveness of engine operations and performance of internal combustion engines. Accumulation of the higher amplitude of both noise and vibration affects the comfort of the engine. So far, most of the research done on the performance, combustion, and emission characteristics only. Less importance is shown in the form engine vibration and sounds created by the engine operation. This paper presents and explores the importance and experimental results of noise and vibration by the compression ignition diesel engine with the fuels of diesel and microalgae biodiesel. The produced microalgae biodiesel blends were SMB10%, SMB20%, and SMB30%. The experimental results were conducted at different engine loads varying across 25%, 50%, 75%, and 100%. The inline, four-cylinder, water-cooled, and naturally aspirated DI diesel engine was used as an experimental setup. From the comparative results between the diesel and microalgae biodiesel, it is found that the use of microalgae blended biodiesel reduced the noise and vibration. The higher the percentage of blends, the greater the reduction in sound and vibration will be. Apart from possessing the performance and emission qualities, the microalgae biodiesel blends proved to be an efficient fuel in reduced vibration and noise qualities too. In three directions, the vibrations were measured as lateral, longitudinal, and vertical vibrations. The vibration in the lateral direction was significantly reduced. Compelling the results, it is understood that the use of the microalgae blends can be sustainable from the perspective of engine wear and tear.

A Transient 3D CFD Thermal Model of the Complete DI Diesel Engine Fuel System

<div class="section abstract"><div class="htmlview paragraph">This paper reports on a transient, three-dimensional computational fluid dynamics (CFD) study of flow and heat transfer in the complete fuel system of an inline 6-cylinder, direct injection (DI) diesel engine used in commercial applications. The CFD software Simerics-MP+ was used for this purpose. Diesel engine development, to meet fuel economy and exhaust emission standards, requires the precise integration of each component in the fuel system in order to reliably deliver the fuel to the combustion chamber as a function of crank angle to the combustion chamber, at the specified injection pressure. Both the model set-up and run times are practical, thus the simulation tool can play a key role in the design and development of diesel engine fuel systems.</div></div>

Sustainability improvement by utilizing polymer waste as an energy source for a diesel engine with alcohol additives

Energy and fossil fuel supplies have been threatened by the depletion of fossil fuels on a global scale, as well as by the constant rise in oil prices and the continual increase in environmental degradation. On the other hand, polymer waste has increased due to its usage in a daily lifestyle because of its cheap cost, ease of production, and adaptability. Indirectly, these polymer wastes are causing some major problems for the ecosystem and other living things. By transforming waste polymers into usable energy, can address for both the non-biodegradability of polymers and the need for an alternative fuel. This research paper aims to evaluate the performance of fuel produced by the pyrolysis of polyethylene polymer. Three distinct alcohol additive blends with polymer fuel were investigated in a single-cylinder direct injection diesel engine for their performance and emission characteristics. The engine efficiency of pentanol was found to be about 3.4% higher than that of base diesel, and with 7% better fuel consumption. Additionally, alcohol additives reduced CO emissions by 3.6%–3.8% and HC emissions by 3.5%–3.8%. The results were further analysed using the design of experiment tool, "Full Factorial Design" to determine the most optimal running condition with fuel consumption of 0.4508 kg/kWh, hydrocarbon of 49 ppm and carbon monoxide 0.265% at half load conditions.

Experimental study on the effect of load and air+gas/fuel ratio on the performances, emissions and combustion characteristics of diesel–LPG fuelled single stationary ci engine

AbstractDue to the issue of combustion stability when using natural gas and the problem of knocking when using both natural gas and hydrogen, liquefied petroleum gas (LPG) is then a good candidate to use for the dual‐fuel concept since it has been proven to be a good solution to limit the pollutants and the excessive use of fossil resources in the aim to support and advance the African Union's and UN's sustainable development goals. In this paper, the effect of load as well as the air + gas/fuel ratio on the performance, emission, and combustion characteristics of a dual‐fuel diesel–LPG engine, single‐cylinder, four‐stroke, direct injection diesel engine with a rated power of 3.5 kW at a speed of 1500 rpm has been carried out. Experiments have been performed in dual‐fuel mode for a range of loads from 0 to 12 kg and a range of volume flow of LPG from 1 to 5.5 L/min, and the results were compared with those obtained from the single‐fuel mode. Results show that the dual‐fuel mode gives better performance and fewer pollutants than the single‐fuel mode. For example, at low load, Brake thermal efficiency, the indicated thermal efficiency, and mechanical efficiency increased by 83.79%, 24.36%, and 41.77%, respectively, and by 57.48%, 19.84%, and 24.37% at high load when we moved from the single‐fuel mode to the dual‐fuel mode. The smoke, carbon monoxide, and NOx decreased by 24.3%, 94.2%, and 96.2% respectively at low load and by 62.3%, 89.8%, and 91.4% at high load. And, no knocking came up during this research compared to natural gas or hydrogen dual‐fuel engines.

Performance and emissions characteristics of a common rail direct injection diesel engine powered by ignition enhancer-biodiesel blends

Performance and emissions characteristics of a common rail direct injection diesel engine powered by ignition enhancer-biodiesel blends

Numerical investigation of different combustion chamber on flow, combustion characteristics and exhaust emissions

This study includes numerical analysis of diesel engine with different bowl geometry. 3D CFD analyzes of the engine with asymmetrical piston geometry were performed in Ansys Forte software. In the study, a single-cylinder, four-stroke and direct injection diesel engine was used. It has been tested where the maximum torque is obtained as the operating condition at 2000 rpm. According to the results obtained from the analyzes, the new combustion chamber system (NCCS) geometry provided a 40.3% reduction in soot emissions while NO emissions increased slightly with the 8-cavity bowl geometry created in the combustion chamber compared to the standard combustion chamber system (SCCS). Increasing air velocity and turbulent kinetic energy (TKE) values in the combustion chamber affected the evaporation levels of the fuels. As a result, the improved mixture formation caused a decrease in incomplete combustion products (CO, HC and soot). The NCCS geometry according to SCCS type, an increase of approximately 4.2% occurred in the calculated squish rates. It has been observed that the increase in the bowl surface area causes the combustion and thus the temperature to spread over a larger area on the piston.

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

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

Investigating the Effect of a Diesel-Refined Crude Palm Oil Methyl Ester-Hydrous Ethanol Blend on the Performance and Emissions of an Unmodified Direct Injection Diesel Engine.

In this research, the optimum condition for the production of refined crude palm oil methyl ester from refined crude palm oil was investigated using the response surface method via the transesterification reaction in a batch process. The refined crude palm oil was obtained by vacuum distillation of crude palm oil to extract some of the free fatty acids from the oil, providing nutritional benefits and reducing the chemical consumption of the production process. The purity of methyl ester in the refined crude palm oil methyl ester was studied to adjust four independent variables: methanol content (11-23 vol %), concentration of potassium hydroxide (4-12 g/L), stirrer speed (100-500 rpm), and reaction time (9-45 min). The results showed that methyl ester had a purity of 96.91 wt % when synthesized under optimal conditions of 18.2 vol % methanol, a potassium hydroxide concentration of 10.0 g/L, a stirring speed of 380 rpm, and a reaction time of 36.4 min at 60 °C. Refined crude palm oil methyl ester was blended with diesel and ethanol to study the feasibility of using the diesel-refined crude palm oil methyl ester-hydrous ethanol blend in an unmodified diesel engine. A comparative study of fuel properties, emissions, and performance of the diesel-refined crude palm oil methyl ester-ethanol blend was used to assess the feasibility of fuel blends (D40RM50E10, D30RM60E10, D20RM70E10, and D10RM80E10) in diesel engines at various engine speeds and loads. The results showed that the D40RM50E10 blend provided the closest performance to diesel and was environmentally friendly, as it provided nitrogen oxide and carbon monoxide emissions 32 and 55% lower than those with diesel, respectively. The test results indicated that the diesel-refined crude palm oil methyl ester-hydrous ethanol blend is an attractive alternative fuel in agricultural engines that reduces diesel consumption and benefits farmers and rural communities.

Multiobjective optimisation of feedforward control maps in dual fuel LPG/diesel engine management systems towards low consumption, low pollutants, and high torque

This paper describes a novel approach to model-based optimisation of dual-fuel LPG/diesel engine control maps. Optimal offline optimisation seeks to achieve low fuel consumption, low emissions, and high driveability at the same time. Experiments were performed with a single-cylinder, four-stroke, direct injection diesel engine with a rated power of 3.5 kW in dual fuel mode for a range of loads from 0 to 12 kg. First, using experimental data, engine performance and emissions were predicted in function of the engine load and the LPG/diesel fuel ratio by two architectures of neural networks: The multilayer perceptron and the radial basis function neural networks. Based on the experimental testing data, the root mean square error was found to be 2.75 × 10−5 for engine torque, 0.0024 for fuel consumption, 0.7 for CO2, and 0.8 for NOx. Then, a multi-objective optimisation environment was developed, which computes the basic control maps for the dual fuel engine settings based on the modelled emission behaviour of the engine. Results showed that engine torque increased by 0.1% and fuel consumption decreased by 20%. These results proved that the proposed method has the capability to develop optimised engine control maps for dual-fuel engines.

Mitigating carcinogenic smoke opacity in a light-duty diesel engine by utilizing cyclohexanol, polyethylene glycol, and 2-methoxyethanol.

Diesel fuel reformulation is an attractive method to reduce hazardous smoke emissions because it does not require modifications to the existing engine infrastructure. As the concerns about global warming and air pollution are mounting, high-efficiency diesel engines with low smoke emissions have become more attractive. This study demonstrates that three alcohols, viz. cyclohexanol, polyethylene glycol, and 2-methoxyethanol, can be added to fossil diesel up to 3% by vol. to reduce carcinogenic smoke emissions in a one-cylinder, common rail direct injection (CRDI) diesel engine. The experimental investigations revealed that smoke could be reduced by up to 66.2%, 39.6% and 14% using 3% by vol. addition of cyclohexanol, polyethylene glycol, and 2-methoxyethanol to diesel, respectively, when compared to pure diesel operation. 1% addition by vol. of cyclohexanol and 2-methoxyethanol could reduce NOx and smoke emissions under all load conditions. CO emissions are slightly higher for all alcohol at high load conditions. HC emissions for the test fuels are lower than pure diesel operation at low load conditions, increasing at high loads. These emissions, however, can be reduced by using suitable after-treatment devices.

Collective influence and optimization of 1-hexanol, fuel injection timing, and EGR to control toxic emissions from a light-duty agricultural diesel engine fueled with diesel/waste cooking oil methyl ester blends

This study attempts to utilize a ternary blend comprising diesel, biodiesel, and 1-hexanol in a direct injection (DI) diesel engine. A response surface methodology (RSM) based optimization with the full factorial experimental design was used to optimize the fuel injection timing and exhaust gas recirculation (EGR) with an objective to maximize the performance of the engine with minimum emissions. Three injection timings and three EGR rates were used. Multiple regression models developed using RSM for the responses were found to be statistically significant. Interactive effects between injection timing and EGR on responses for the blends were studied. From a desirability approach, a HX20 blend (diesel 50 v/v% + biodiesel 30 v/v% + 1-hexanol 20 v/v%) injected at lesser fuel injection timing and EGR rate delivered optimum emission and performance characteristics. Confirmatory tests validated the models to be adequate. With reference to diesel, at optimum conditions, there was a significant reduction in nitrogen oxides (NOx) emission with a marginal increase in smoke, hydrocarbon (HC) and carbon monoxide (CO) emissions. Also, it was found that there was minimal loss in brake thermal efficiency (BTE) of the engine. With respect to waste cooking oil methyl ester operation, the blend reduced nitrogen oxides (NOx), smoke, carbon monoxide (CO) and hydrocarbon (HC) emissions significantly with marginal loss in BTE.

Effective utilization of waste pork fat as a potential alternate fuel in CRDI research diesel engine – Waste reduction and consumption technique

This work utilized the conventional transesterification process to convert waste pork fat into pork fat biodiesel. The produced biodiesel was meant to serve as a diesel fuel substitution for common rail direct injection (CRDI) diesel engines. Butylated Hydroxytoluene (BHT) as an antioxidant doping with waste pork fat biodiesel-diesel blend has not been analyzed in CRDI diesel engines. Therefore, to improve the ignition process and reduce the engine exhaust emissions in a research CRDI diesel engine, the BHT was employed to combine with diesel-biodiesel mixtures in this work. BHT antioxidants are partially mixed (BHT 50, 100, and 150 ppm) to improve the physicochemical qualities of test fuel and enhance the combustion process of diesel-biodiesel blends (B20). The antioxidant purity was analyzed by energy dispersive X-ray analysis (EDX), structures were analyzed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyzer spectrograph was utilized to study the biodiesel chemical components. After mixing the BHT, the overall phase of the base fuel remained constant. The experiment outcomes revealed that the biodiesel had higher cylinder pressure than the other test fuels, and the BHT100 ppm blend had a higher heat release rate (HRR). B20BHT100 blend shows 3.98% higher brake thermal efficiency (BTE) at full load operation than pure biodiesel but lowered to diesel fuel. Biodiesel (B100) decreases the smoke opacity by 4.5% compared to diesel fuel. BHT has been incorporated into the biodiesel blend to minimize oxides of nitrogen (NOx) emissions at all loads. The B20BHT150 blend decreased NOx emissions by 5.06% more than diesel fuel at maximum load. Compared to pure biodiesel, the B20 blends reduce carbon monoxide (CO) emissions by 7.1% and hydrocarbon emission (HC) by 12.5%. This research found that adding BHT to biodiesel blends lowers NOx emissions with a slight impact on performance.

Thermal and experimental analyses of thermal barrier coated pistons

ABSTRACT The thermal analysis of pistons with two different thermal barrier coatings (TBC) is carried out in this research work. TBC comprising Yttria stabilized zirconia (YSZ), and YSZ + Cerium oxide (CeO2) is applied to an aluminum alloy piston. The coating consists of two layers; the first is the bond coat, and the second is the top coat. Three different thicknesses of the top coat are chosen, viz., 0.3 mm, 0.6 mm, and 0.9 mm. SOLIDWORKS is used to draw the piston and different thicknesses of the layers (top coatings). ANSYS software is used for performing structural and steady-state thermal analyses on the piston surface. After the analysis, experiments are conducted on a single-cylinder, air-cooled, direct injection (DI) diesel engine fitted with TBC pistons. The performance of the engine fitted with both coated pistons is evaluated and compared with that of the uncoated piston engine operation. The brake thermal efficiency (BTE) for the JME20 fuel blend is increased by about 2.8%, and 6.5% for engines fitted with YSZ and YSZ+CeO2 coated pistons, respectively, at full load. The engine’s brake specific fuel consumption (BSFC) is improved by 2.5%, and 5.3% for the YSZ and YSZ+CeO2 coated piston fitted engines, respectively, for JME20.

Nanoparticles Additives for Diesel/Biodiesel Fuel Blends as a Performance and Emissions Enhancer in the Applications of Direct Injection Diesel Engines: A comparative Review

Nanoparticles Additives for Diesel/Biodiesel Fuel Blends as a Performance and Emissions Enhancer in the Applications of Direct Injection Diesel Engines: A comparative Review

Synthesis, Characterization and Application of SnO2@rGO Nanocomposite for Selective Catalytic Reduction of Exhaust Emission in Internal Combustion Engines

In this experimental investigation, a procreation approach was used to produce a catalyst based on SnO2@rGO nanocomposite for use in a selective catalytic reduction (SCR) system. Plastic waste oil is one such alternative that helps to ensure the survival of fossil fuels and also lessens the negative impacts of improper waste disposal. The SnO2@rGO nanocomposite was prepared by fine dispersion of SnO2 nanoparticles on monolayer-dispersed reduced graphene oxide (rGO) and carefully investigated for its potential in adsorbing CO, CO2, NOX, and hydrocarbon (HC). The as-synthesized SnO2@rGO nanocomposite was characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction spectroscopy, thermogravimetry, and surface area analyses. Then, the impact of catalysts inside the exhaust engine system was evaluated in a realistic setting with a single-cylinder, direct-injection diesel engine. As a result, the catalysts reduced harmful pollution emissions while marginally increasing brake-specific fuel consumption. The nanocomposite was shown to exhibit higher NOX adsorption efficiencies when working with different toxic gases. Maximum reductions in the emission of NOX, hydrocarbons, and CO were achieved at a rate of 78%, 62%, and 15%, respectively. These harmful pollutants were adsorbed on the active sites of catalyst and are converted to useful fuel gases through catalytic reduction thereby hindering the trajectory of global warming.

Performance and emission analysis of single‐cylinder direct injection engine running with cottonseed‐ethyl oleate biodiesel blends

AbstractIn this study, the performance and exhaust emissions of a direct injection (DI) diesel engine are compared using blended fuels consisting of cottonseed oil (CSO) and ethyl oleate (EO) at various diesel proportions. The uniqueness of this work lies in the fact that it utilizes engine emission and performance studies with blended fuel made from CSO and EO at a higher volume (%) composition than is typically used. Biodiesel reduces brake‐specific fuel consumption (BSFC) compared to CSO, even though it is higher than diesel due to viscosity and heating value. The brake thermal efficiency (BTE) was enhanced until 800 rpm and afterward reduced as the engine's speed continued to increase. Among all the blends, BTE was recorded as highest for CE20D and minimum for CSO. Because EO was unsaturated, culminating in a reasonably short ignition delay, NOx emissions in fused biofuel were marginally more significant than in diesel. The concentrations of UHC and CO reduced as the concentrations of CSO and EO increased, caused by a rise in the oxygen concentration by mass portion. The results of the combustion and emission tests suggest that CE20D has the potential to be a sustainable alternative fuel.

Thermodynamic Performance of an Engine by Modifying Piston Bowl Geometries Fuelled by SME-100, LA-100, KB-100 Biodiesel Blends, and Diesel

Simulation of Direct injection (DI) compressed ignition (CI) engine working on diesel thermodynamic cycle on diesel-Rk software carried out for evaluating the effect on thermal performance. The analysis of an engine was worked out by applying different bowl geometrical shapes and by testing with different fuels. Further same compositions were tested on an experimental test rig having a set-up of (compressed ignition, single cylinder, four strokes, air-cooled, direct injection) diesel engine at constant crank speed. Hemispherical (HCC), Shallow depth (SCC), Re-entrant (RCC), Double wedge shallow, and Toroidal (TCC) piston geometries were created in solid-work and analyzed with B-100 blend of SME (Soybean Methyl Ester), KB (Karanja Biodiesel), LA (Roselle Biodiesel) and diesel further they were analyzed and their effects have investigated experimentally and numerically at fully loaded condition, with a constant crank speed of 1500 rpm and by setting constant compression ratio at 17.5. BSFCs were higher by 21.03%, 12.97%, and 12.96% for SME100, KB100, and LA100 with hemispherical, toroidal, and re-entrant type combustion chambers compared with the diesel fuel. Indicated thermal efficiencies and ignition delay periods were reported slightly lower for different blends and pure biodiesel than diesel at specific load conditions whereas combustion durations were reported higher compared to diesel.