H.G. How

Effects of Jatropha biodiesel on the performance, emissions, and combustion of a converted common-rail diesel engine

An experimental investigation into the effects of Jatropha biodiesel fuels on the engine performance, emissions, and combustion characteristics of a single-cylinder high-pressure common-rail diesel engine was performed under six different load operations (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 MPa). The test fuels included a conventional diesel fuel and three different blends of Jatropha biodiesel fuel (JB10, JB30, and JB50). The results revealed that the biodiesel blended fuels had a significant influence on the brake specific fuel consumption (BSFC) at all of the engine load conditions examined. In general, the use of Jatropha biodiesel blends resulted in a reduction in brake specific nitrogen oxide (BSNOx), brake specific carbon monoxide (BSCO), and smoke emissions, regardless of the load conditions. A large reduction of 20.2% in BSNOx emissions and 69.5% in smoke opacity were found for the engine when it was fuelled with the biodiesel blends. In terms of the engine combustion characteristics, a slightly shorter ignition delay (ID) and faster combustion duration were found to occur with the use of biodiesel blends under all loading operations. It was revealed that the peak apparent heat release rate (AHRR) for biodiesel blends is lower during low load operation; the AHRR was found to be comparable to that of baseline diesel during high-load operation. Finally, the vibration results demonstrated that the largest reduction, 11.3%, in the root mean square (RMS) of acceleration in comparison with the baseline diesel was obtained with JB50 at an engine load of 0.5 MPa.

Influence of engine operating variable on combustion to reduce exhaust emissions using various biodiesels blend

This study focused mainly on the behavior of biodiesel operated under various operating conditions. The experiment was conducted with B20 of three potential biodiesel sources, namely, rice bran, Moringa and sesame oil. A significant outcome was observed from the test results, which showed that the brake thermal efficiency of the biodiesel blend was about 3.4% lower under constant speed running conditions than constant torque operating conditions. Similarly, about 6.5% lower exhaust gas temperatures under constant speed running conditions with lower peak pressure were found than under constant torque testing conditions. On the subject of emission, it is seen that the testing conditions also have an influence on exhaust emission. For instance, under constant speed running conditions, the engine produces about 19.5% lower NO and 19% higher HC than under constant torque running conditions. A similar influence was also found in the pressure and heat release rate. However, there is a clear variation found in the results under different operating conditions. Therefore, it is necessary to test the fuel under various operating conditions, such as constant torque, constant speed, variable injection timing, for the optimal use of biodiesel.

Attempts to minimize nitrogen oxide emission from diesel engine by using antioxidant-treated diesel-biodiesel blend

The study represents a comprehensive analysis of engine exhaust emission variation from a compression ignition (CI) diesel engine fueled with diesel-biodiesel blends. Biodiesel used in this investigation was produced through transesterification procedure from Moringa oleifera oil. A single cylinder, four-stroke, water-cooled, naturally aspirated diesel engine was used for this purpose. The pollutants from the exhaust of the engine that are monitored in this study are nitrogen oxide (NO), carbon monoxide (CO), hydrocarbon (HC), and smoke opacity. Engine combustion and performance parameters are also measured together with exhaust emission data. Some researchers have reported that the reason for higher NO emission of biodiesel is higher prompt NO formation. The use of antioxidant-treated biodiesel in a diesel engine is a promising approach because antioxidants reduce the formation of free radicals, which are responsible for the formation of prompt NO during combustion. Two different antioxidant additives namely 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol) (MBEBP) were individually dissolved at a concentration of 1% by volume in MB30 (30% moringa biodiesel with 70% diesel) fuel blend to investigate and compare NO as well as other emissions. The result shows that both antioxidants reduced NO emission significantly; however, HC, CO, and smoke were found slightly higher compared to pure biodiesel blends, but not more than the baseline fuel diesel. The result also shows that both antioxidants were quite effective in reducing peak heat release rate (HRR) and brake-specific fuel consumption (BSFC) as well as improving brake thermal efficiency (BTE) and oxidation stability. Based on this study, antioxidant-treated M. oleifera biodiesel blend (MB30) can be used as a very promising alternative source of fuel in diesel engine without any modifications.

Effect of injection timing and EGR on engine-out-responses of a common-rail diesel engine fueled with neat biodiesel

Nowadays, diesel-powered engines are becoming attractive worldwide due to their superior fuel economy, higher efficiency and excellent reliability. Biodiesel can be considered as the most promising and in demand alternative fuel because it is a non-toxic, biodegradable and renewable fuel. This work attempts to simultaneously reduce the BSNOx and smoke from the levels of fossil diesel by using palm methyl ester (PME) biodiesel. In addition, this paper describes the conversion of a common-rail injection system with a custom-made electronic control system, focusing on hardware development, the engine control unit and fuel delivery system development. Parametric studies dealing with injection timing and exhaust gas recirculation (EGR) variation using neat palm biodiesel were performed and compared with baseline diesel. The tests were performed at a constant speed and load of 1500 rpm and 0.4 MPa, respectively. Firstly, the start of injection (SOI) timing was varied from TDC to −25° ATDC to demonstrate the flexible control of the custom-made engine controller. Later, the SOI timing was kept at an optimum of −11° ATDC and the EGR rates were adjusted (i.e. 0–50%). The experimental results indicated that both the injection timing and EGR variation had a prominent effect on the engine performance, emissions and combustion characteristics for an engine operating with baseline diesel or neat biodiesel. Based on the highest brake thermal efficiency (BTE) and a reasonable NOx level, the optimum injection timing is found to be at −11° ATDC for both the baseline diesel and biodiesel operation. A wider range of EGR rates from 0% to 50% were investigated to bring down the NOx levels from the EURO II limit to meet with more stringent EURO limits. It was found that with the PME fuel, engine operation at 30% EGR resulted in the optimum trade-off between BSNOx and smoke emissions. In fact, simultaneous BSNOx and smoke reduction from the levels of fossil diesel is possible with the use of PME biodiesels in parallel with the implementation of late SOI timing or a higher EGR rate in diesel engines.

Evaluation of a novel biofuel from unwanted waste and its impact on engine performance, emissions, and combustion characteristics in a diesel engine

The effect of a new biofuel source derived from waste palm oil mill effluent (POME) addition to diesel on engine performance, emissions, and combustion characteristics was investigated in a single-cylinder diesel engine under six different speed operations and at full load conditions. The experimental results suggested that there are some penalties in engine torque, brake power, brake specific fuel consumption (BSFC), and brake specific nitrogen oxide (BSNOx) with the presence of Biopro Diesel™ fuel in the blend. Moreover, there is an improvement in exhaust emissions with lower brake specific hydrocarbons (BSHC), brake specific carbon monoxide (BSCO) and smoke emissions by using Biopro Diesel™ fuel blends across all engine speeds. Besides, the tip surfaces of the injectors running with Biopro Diesel™ blends were found to be cleaner than that of an injector running with fossil diesel. Moreover, there is an improvement in the combustion process with a shorter total burning angle for Biopro Diesel™ fuel blends than that of diesel at all engine speeds. Overall, the results suggested that biofuel derived from waste POME blended with fossil diesel can be used satisfactorily in an unmodified diesel engine.

Effect of Ethanol-Coconut Oil Methyl Ester on the Performance, Emission and Combustion Characteristics of a High-Pressure Common-Rail DI Engine

The effects of using ethanol as additive to biodiesel-diesel blends on engine performance, emissions and combustion characteristics was investigated on a four-cylinder, turbocharged and high-pressure common-rail direct injection diesel engine. Three test fuels have been compared: baseline diesel, coconut oil methyl ester (CME) with 20% of biodiesel by volume (B20) and 5% of ethanol and 20% of CME by volume (B20E5). The tests were performed in steady state conditions at 2000 rpm with 25%, 50% and 75% load setting conditions. The results indicate that higher brake specific fuel consumption and brake thermal efficiency is observed when operating with B20 and B20E5 blend. B20E5 blend shows reduction in smoke opacity, CO and NOx emissions compared to baseline diesel fuel. In terms of combustion characteristics, B20E5 shows slightly higher in both of the peak pressure and peak of HRR at low engine load.

Comparative assessment of performance, emissions and combustion characteristics of gasoline/diesel and gasoline/biodiesel in a dual-fuel engine

In recent years, rapid growth in population, development, and industrialization have led to a high demand for energy worldwide. Biofuels from bio-based products can be considered an alternative to fossil fuels used in the transport sector. However, the use of biodiesel in conventional diesel combustion engines has usually caused lower thermal efficiency and higher specific fuel consumption. Using alternative fuels and switching to promising combustion technologies such as low temperature combustion (LTC) are reliable approaches to address this issue. This research aims to use biofuels as an alternative energy source for engines operating in dual-fuel combustion mode. The effects of diesel/biodiesel strategies on dual-fuel combustion were investigated. This dual-fuel combustion mode proposes port fuel injection of gasoline and direct injection of diesel/biodiesel fuel with rapid in-cylinder fuel blending. The results of engine performance, emissions, and cylinder pressure were recorded and analyzed. The results showed that engines operating under dual-fuel combustion mode could achieve high efficiency with near zero nitrogen oxide (NOx) and smoke emissions. The biodiesel–gasoline dual-fuel combustion mode showed lower hydrocarbon (HC) and carbon monoxide (CO) emissions than the diesel–gasoline dual-fuel combustion mode. The oxygen content in biodiesel is especially useful in limiting locally fuel rich regions, resulting in improved combustion and thereby reducing HC and CO emissions simultaneously.

Effect of Premixed Diesel Fuel on Partial HCCI Combustion Characteristics

This study investigated the effects of premixed diesel fuel on the auto-ignition characteristics in a light duty compression ignition engine. A partial homogeneous chargecompression ignition (HCCI) engine was modified from a single cylinder, four-stroke, direct injection compression ignition engine. The partial HCCI is achieved by injecting diesel fuel into the intake port of the engine, while maintaining diesel fuel injected in cylinder for combustion triggering. The auto-ignition of diesel fuel has been studied at various premixed ratios from 0 to 0.60, under engine speed of 1600 rpm and 20Nm load. The results for performance, emissions and combustion were compared with those achieved without premixed fuel. From the heat release rate (HRR) profile which was calculated from in-cylinder pressure, it is clearly observed that two-stage and three-stage ignition were occurred in some of the cases. Besides, the increases of premixed ratio to some extent have significantly reduced in NO emission.