Modification of a Direct Injection Diesel Engine in Improving the Ignitability and Emissions of Diesel–Ethanol–Palm Oil Methyl Ester Blends

Blending diesel with biofuels, such as ethanol and palm oil methyl ester (PME), enhances the fuel properties and produces improved engine performance and low emissions. However, the presence of ethanol, which has a small cetane number and low heating value, reduces the fuel ignitability. This work aimed to study the effect of injection strategies, compression ratio (CR), and air intake temperature (Ti) modification on blend ignitability, combustion characteristics, and emissions. Moreover, the best composition of diesel–ethanol–PME blends and engine modification was selected. A simulation was also conducted using Converge CFD software based on a single-cylinder direct injection compression ignition Yanmar TF90 engine parameter. Diesel–ethanol–PME blends that consist of 10% ethanol with 40% PME (D50E10B40), D50E25B25, and D50E40B10 were selected and conducted on different injection strategies, compression ratios, and intake temperatures. The results show that shortening the injection duration and increasing the injected mass has no significant effect on ignition. Meanwhile, advancing the injection timing improves the ignitability but with weak ignition energy. Therefore, increasing the compression ratio and ambient temperature helps ignite the non-combustible blends due to the high temperature and pressure. This modification allowed the mixture to ignite with a minimum CR of 20 and Ti of 350 K. Thus, blending high ethanol contents in a diesel engine can be applied by advancing the injection, increasing the CR, and increasing the ambient temperature. From the emission comparison, the most suitable mixtures that can be operated in the engine without modification is D50E25B25, and the most appropriate modification on the engine is by increasing the ambient temperature at 350 K

Performance and emission opacity of canola and soybean biodiesel fuel in a diesel engine

Biodiesel is a renewable fuel known to produce more environmentally friendly emissions compared to diesel fuel. However, at times it has been reported as exhibiting a much lower engine performance compared to standard diesel fuel. Biodiesel fuel has the potential to achieve similar performance as compared to diesel fuel when the optimum percentage of biodiesel blend is used. In this study, an experiment was conducted to determine the performance and opacity of emissions collected from soybean biodiesel and canola biodiesel fuel by using a YANMAR TF90 single cylinder direct injection diesel engine. The objective of this study is to determine the best percentage of diesel-soybean and diesel-canola fuel mixture that would result in the best performance of an engine. The experiment investigated the brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), brake power (BP), and torque generated by the engine using different biodiesel fuel percentages at varying engine speeds. Additionally, the emission opacity was investigated to identify the most favourable fuel percentage for optimised biodiesel compared to the quality obtained from soybean and canola soybean biodiesel. The results from the experiment clearly show that the engine using biodiesel fuel has a slightly lower performance as compared to the engine that only used diesel fuel for all percentages used. However, at low speeds, a BTE of 40% canola biodiesel was higher compared to diesel and soybean biodiesel. The BSFC for all biodiesel fuel was found to be slightly higher than diesel, except for BC40, which was greater for BSFC compared to other blends used at much lower engine speeds. Engine emission opacity of biodiesel was recorded to be less than diesel fuel at all engine speeds, but slightly higher for BC5, BS5 and BS20 due to the insufficient air intake to the engine. Engine performance and emission opacity of all biodiesel fuels were found to be similar to diesel fuel. From the results relating to engine performance and emission, canola biodiesel was found to be an excellent biodiesel product to be used in a diesel engine since it had a higher BTE, lower BSFC and a lower opacity which was greater than those of soybean biodiesel blends. Therefore, biodiesel can be blended in a diesel engine at a higher percentage while maintaining engine performance and reducing engine emission

Combustion characteristics of hydrogen direct injection in a helium–oxygen compression ignition engine

The ignition of hydrogen in compression ignition (CI) engines by adding noble gas as a working gas can yield excellent thermal efficiency due to its high specific heat ratio. This paper emphasizes the potential of helium–oxygen atmosphere for hydrogen combustion in CI engines and provides data on the engine configuration. A simulation was conducted using Converge CFD software based on the Yanmar NF19SK engine parameters. Helium–oxygen atmosphere compression show promising hydrogen autoignition results with the in-cylinder temperature was significantly higher than that of air during the compression stroke. In a compression ignition engine with a low compression ratio (CR) and intake temperature, helium–oxygen atmosphere is recognized as the best working gas for hydrogen combustion. The ambient intake temperature was sufficient for hydrogen ignition in low CR with minimal heat flux effect. The best intake temperature for optimum engine efficiency in a low CR engine is 340 K and the engine compression ratio for optimum engine efficiency at ambient intake temperature is CR12 with an acceptable cylinder wall heat flux value. The helium–oxygen atmosphere as a working gas for hydrogen combustion in CI engines should be consider based on the parameter provided for clean energy transition with higher thermal efficiency

Investigation of diesel-ethanol blended fuel properties with palm methyl ester as co-solvent and blends enhancer

Diesel engine is known as the most efficient engine with high efficiency and power but always reported as high fuel emission. Malaysia National Automotive Policy (NAP) was targeting to improve competitive regional focusing on green technology development in reducing the emission of the engine. Therefore, ethanol was introduced to reduce the emission of the engine and while increasing its performance, Palm methyl ester was introduced as blend enhancer to improve engine performance and improve diesel-ethanol blends stability. This paper aimed to study the characteristics of the blends and to prove the ability of palm-methyl-ester as co-solvent in ethanol-diesel blends. Stability and thermophysical test were carried out for different fuel compositions. The stability of diesel-ethanol blended was proved to be improved with the addition of PME at the longer period and the stability of the blends changed depending on temperature and ethanol content. Density and viscosity of diesel-ethanol-PME blends also give higher result than diesel-ethanol blends and it's proved that PME is able to increase density and viscosity of blends. Besides, heating value of the blends also increases with the increasing PME in diesel-ethanol blends

Investigation of diesel-ethanol blended fuel properties with palm methyl ester as co-solvent and blends enhancer

Diesel engine is known as the most efficient engine with high efficiency and power but always reported as high fuel emission. Malaysia National Automotive Policy (NAP) was targeting to improve competitive regional focusing on green technology development in reducing the emission of the engine. Therefore, ethanol was introduced to reduce the emission of the engine and while increasing its performance, Palm methyl ester was introduced as blend enhancer to improve engine performance and improve diesel-ethanol blends stability. This paper aimed to study the characteristics of the blends and to prove the ability of palm-methyl-ester as co-solvent in ethanol-diesel blends. Stability and thermophysical test were carried out for different fuel compositions. The stability of diesel-ethanol blended was proved to be improved with the addition of PME at the longer period and the stability of the blends changed depending on temperature and ethanol content. Density and viscosity of diesel-ethanol-PME blends also give higher result than diesel-ethanol blends and it's proved that PME is able to increase density and viscosity of blends. Besides, heating value of the blends also increases with the increasing PME in diesel-ethanol blends