School of Civil & Environmental Engineering

Biodiesel is a renewable and sustainable alternative fossil fuel that is derived from vegetable oils and animal fats. This study investigates the production, characterization, and effect of biodiesel blends from two prominent feedstocks, namely, palm and coconut (PB30 and CB30), on engines. To aggregate the advantages of high ignition quality of palm and high oxygen content of coconut, combined blend of this two biodiesels (PB15CB15) is examined to evaluate its effect on engine performance and emission characteristics. Biodiesels are produced using the alkali catalyzed transesterification process. Various physicochemical properties are measured and compared with the ASTM D6751 standard. A 10 kW, horizontal, single-cylinder, four-stroke, and direct-injection diesel engine is employed under a full load and varying speed conditions. Biodiesel blends produce a low brake torque and high brake-specific fuel consumption (BSFC). However, all emissions, except for NOx, are significantly reduced. PB15CB15 improves brake torque and power output while reducing BSFC and NOx emissions when compared with CB30. Meanwhile, compared with PB30, PB15CB15 reduces CO and HC emissions while improving brake thermal efficiency. The experimental analysis reveals that the combined blend of palm and coconut oil shows superior performance and emission over individual coconut and palm biodiesel blends.

A biodiesel is a clean-burning alternative fuel. It has drawn attention of the energy researchers over the last two decades as a solution to problems of environmental concerns, rising fossil fuel price, increasing dependency on foreign energy sources. However, it is susceptible to oxidative degradation due to autoxidation in the presence of oxygen, which hinders its widespread use. The addition of an antioxidant to it reduces this phenomenon significantly. It is expected that antioxidants may affect the clean burning characteristic of a biodiesel. Coconut (Cocos nucifera) and Jatropha (Jatropha curcas) are two promising feedstock growing in the South-East Asian region. This paper presents an experimental investigation of the effect of addition of an antioxidant on the performance and emission characteristics of a four-cylinder diesel engine fueled with 20% blends of two biodiesels (CB20 and JB20). A biodiesel from coconut oil was produced by transesterification process using potassium hydroxide (KOH) as a catalyst. Jatropha biodiesel production was preceded by an esterification step, using sulfuric acid as a catalyst. To study the antioxidant effect, two low-cost synthetic antioxidants, 2(3)-tert-butyl-4-methoxyphenol (BHA) and 2,6-di-tert-butyl-4-methylphenol (BHT), at a concentration of 2000 ppm, were used in this
study. Addition of antioxidants increased their oxidation stability without causing any negative effect on other physicochemical properties. BHT and BHA were found to increase the stability of JB20 and CB20, respectively. Performance results indicate that JB20 and CB20 showed, respectively, 0.95% and 2.97% lower mean brake power (BP) and 5.02% and 4.76% higher mean brake-specific fuel consumption (BSFC) than to diesel. The addition of antioxidants increased BP and reduced BSFC slightly. Emission results show that untreated JB20 and untreated CB20 increased nitrogen monoxide (NO) emission by 5.52% and 8.02%, but reduced carbon monoxide (CO) and hydrocarbon (HC) emission. Antioxidant-treated blends reduced NO emission by 2.6–5.0%, but increased CO emission by 4.9–20.8% and HC emission by 23.2–40.2% compared to B20 depending on feedstock. Thus, antioxidant-treated JB20 and CB20 blends can be used in diesel engines without any modification.

This study aims to investigate the effects of palm or coconut biodiesel blend and their combination on the performance and emissions of a single-cylinder diesel engine. A 20% v/v blend of palm biodiesel (PB20) or coconut biodiesel (CB20) and varying percentage mixtures of these two feedstocks (PB15CB5, PB10CB10, and PB5CB15) were used in the experiments. Biodiesel was produced using one-step transesterification. Physicochemical analysis showed that both palm and coconut biodiesel met the specifications of ASTM D6751. A 10 kW, horizontal, one-cylinder, four-stroke direct injection diesel
engine was used to carry out tests under full load conditions at varying speeds from 1400 to 2400 rpm with an interval of 200 rpm. Burning of CB20 reduced break power by 1.72% and increased brake-specific fuel consumption (BSFC) and NOx emission by 4.07% and 4.49%, respectively. Conversely, burning of PB20 negligibly reduced brake power and increased NOx emission by only 1.79%. Meanwhile, combined palm−coconut biodiesel at a constantfinal blend reduced NOx emission by 0.54% to 1.85% and slightly improved brake power and BSFC. Thus, the advantages of the high cetane number of coconut and the high ignition quality of palm biodiesel were aggregated in the combined blends.

The purpose of this research is experimental study of Calophyllum inophyllum (CI) based Trymethylolpropane (TMP) ester as energy saving and biodegradable lubricant and compare with commercial lubricant and paraffin mineral oil by using four ball tribometer. CI based TMP ester is a renewable lubricant that is non-edible, biodegradable, non-toxic and has a net zero greenhouse gases. The TMP ester was produced from CI oil, which has high lubricity properties such as higher density, higher viscosity at both 40°c and 100°c and higher viscosity index (VI). Experiment was conducted during 3600s with constant load of 40 kg and constant sliding speed of 1200 rpm at temperature of 50°C, 60°C, 70°C, 80°C, 90°C and 100°C for both three types of lubricant. The results show that CI TMP ester had the lowest coefficient of friction (COF) as well as lower consumption of energy at all test temperature, but the worn surface roughness average (Ra) and wear scar diameter were higher compared to paraffin mineral oil and commercial lubricant. Before 80°C, CI TMP ester actually has higher flash temperature parameter (FTP) than paraffin mineral oil and as the temperature increases, the FTP of TMP ester decreases. The worn surfaces of the stationary balls were analyzed by SEM and results show that CI TMP ester have the highest wear compared to paraffin mineral oil and lowest wear compared to commercial lubricant. However, CI TMP ester is environmentally desired, competitive to commercial lubricant and should be encouraged.Accepted Author Version. Not yet edited or proofed. Please see disclaimer on the article abstract page.

This paper presents experimental test results of a new compressed natural gas direct injection (CNGDI) engine that has been developed by modifying a multicylinder gasoline port injection engine. The major modifications done are (1) a modification of the injection system to gas direct injection using new high-pressure gas injectors, (2) a change of the compression ratio from 10 to 14 through modification of piston and cylinder head, (3) and new long edge spark plugs. The CNG pressure at the common rail is kept constant at 20 bar. The engine has been operated at wide open throttle (WOT) condition to compare all the results with the original base engine. Hence, two engines are tested in this investigation. The test was conducted on a computer-controlled dynamometer to measure brake power; specific fuel consumption; volumetric efficiency; and exhaust emissions such as carbon monoxide (CO), oxides of nitrogen (NO x), and unburned hydrocarbon (HC). The objective of this investigation is to compare the test results between a CNGDI engine and a gasoline engine. It was found that the CNGDI engine produces a 4% higher brake power at 6000 rpm as compared to the original gasoline-fueled engine. The average brake specific fuel consumption (BSFC) of the CNGDI engine was slightly lower (about 0.28%) than the base engine. The CNGDI engine reduces 50% NO x emission as compared to base engine. However, the CNGDI engine produces higher HC and CO emissions as compared to the base engine by 34 and 48%, respectively. The results of this experiment will be used to further improve the CNGDI engine as well as to develop a new CNGDI car. The detailed results including fuel mapping are presented with discussions.

Depletion of petroleum derived fuel and environmental concern has promoted to look over the biofuel as an alternative fuel sources. But a complete substitution of petroleum derived fuels by biofuel is impossible from the production capacity and engine compatibility point of view. Yet, marginal replacement of diesel by biofuel can prolong the depletion of petroleum resources and abate the radical climate change caused by automotive pollutants. Energy security and climate change are the two major driving forces for worldwide biofuel development which also have the potential to stimulate the agro-industry. Nonetheless, there are other problems associated with biofuel usage such as automotive engine compatibility in long term operation and also food security issues that stem from biofuel production from food-grade oil-seeds. Moreover, severe corrosion, carbon deposition and wearing of engine parts of the fuel supply system components are also caused by biodiesel. Discussing all this advantages and disadvantages of biodiesel, it is comprehended that, a dedicated biodiesel engine is the ultimate solution for commercializing biodiesel. Brazil successfully boosted their bioethanol marketing by introducing flexible-fuel vehicles (FFV), which have a dedicated engine for both ethanol and gasoline. A similar approach can bring a breakthrough in biofuel commercialization and production. So dedicated biofuel engine is a challenge for mass commercialization and utilization of biofuel. In this lecture worldwide biofuel scenario is assessed by biofuel policies and standards. Different biofuel processing techniques are also summarized. Some guidelines on dedicated biofuel engine are prescribed. Minor modifications on the engine may not cost much; but continuous research and development is still needed.

This research work focuses on investigating the lubricity and analyzing the engine characteristics of diesel-biodiesel blends with fuel additives (titanium dioxide (TiO2) and dimethyl carbonate (DMC)) and their effect on the tribological properties of a mineral lubricant. A blend of palm-sesame oil was used to produce biodiesel using ultrasound-assisted transesterification. B30 (30% biodiesel + 70% diesel) fuel was selected as the base fuel. The additives used in the current study to prepare ternary fuel blends were TiO2 and DMC. B30 + TiO2 showed a significant reduction of 6.72% in the coefficient of friction (COF) compared to B30. B10 (Malaysian commercial diesel) exhibited very poor lubricity and COF among all tested fuels. Both ternary fuel blends showed a promising reduction in wear rate. All contaminated lubricant samples showed an increment in COF due to the dilution of combustible fuels. Lub + B10 (lubricant + B10) showed the highest increment of 42.29% in COF among all contaminated lubricant samples. B30 + TiO2 showed the maximum reduction (6.76%) in brake-specific fuel consumption (BSFC). B30 + DMC showed the maximum increment (8.01%) in brake thermal efficiency (BTE). B30 + DMC exhibited a considerable decline of 32.09% and 25.4% in CO and HC emissions, respectively. The B30 + TiO2 fuel blend showed better lubricity and a significant improvement in engine characteristics.