Abstract: Diesel engines are high compression ignition engine which are now very vastly used for heavy vehicles and machineries. Diesel fuel is compressed under the right condition to ignite inside the constant volume chamber. Researchers have been studying for many years on ways to increase the efficiency of diesel engine as well as reduce the emission. The main idea of this research is to understand the effect of temperature on the spray characteristics, as well as fuel-air mixing characteristics. These are the characteristics responsible for ignition of diesel sprays. This research is first conducted by investigating the influence of biodiesel properties and ambient condition on the mixture formation especially at early stage of fuel-air premixing. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to capture the real images of spray evaporation, spray length, and mixture formation with the time changes. The values of the temperature were recorded at ambient temperature, 55°C, 70°C, 85°C as well as 100°C. Injection pressure of 0.1 MPa up to 0.7 MPa was induced into the chamber with an increment of 0.1 MPa. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increase in block temperature increases the ambient temperature inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing.
Abstract: Despite years of emission-reduction attempts, biodiesel combustion still have problem of emitting NOx, CO and particulate matter (PM) into the atmosphere. To reduce emissions, the improvements throughout the combustion process have been considered with the enhancement fuel-air mixing. Optical visualization technique is very essential due to its ability to record real time color image of fuel-air premixing and flame development during burning process. The purpose of this study is to determine the relation between mixture formation and flame development of burner combustion using optical visualization technique and image processing technique. Blending of biodiesel ratio was varied from 5 vol% (B5) – 15 vol% (B15). Water content under emulsified biodiesel was varied up to 15 percent, and equivalence ratio from 0.6 to 2.0. The real spray image of emulsified biodiesel and different equivalence ratio were captured by direct photography method together with color digital camera. The images of the spatial distribution of fuel-air mixing and natural flame luminosity will be further analyzed and to obtain information of the flame development in order to understand the influences of fuel-air premixing on combustion process and burning process. Analysis of spray evaporation and observations of combustion process reveal that the mixture formation exhibit influences to the ignition process and flame development.
Abstract: Now-a-days the demand of alternative fuel is continuously increasing all over the world due to the rapid depletion of fossil fuel and increased global demand. Biodiesel is renewable and sustainable energy source derived from vegetable oils and animal fats which can be the best substitute of fossil fuel. This paper investigates the property of different biodiesel such as palm, coconut and their blends with conventional diesel also analyzed the engine performance like engine break power, speed, break specific fuel consumption (BSFC), torque in diesel engine. In this paper 20% palm biodiesel with diesel (P20), 20% coconut biodiesel with diesel (C20), 30% palm biodiesel with diesel (P30), 30% coconut biodiesel with diesel (C30) and combination of 15% palm biodiesel and 15% of coconut biodiesel with diesel (C15P15) were used for study. Biodiesel was produced by using transesterification process. The density and kinematic viscosity for C15P15 fuel is slightly higher and flash point is slightly lower than diesel fuel as well as others two biodiesel blends whereas pure palm oil biodiesel shows the higher flash point and acid value. Engine performance test was carried out at 75 kg load condition with variable speeds of 1400 rpm to 2000 rpm at an interval of 200 rpm. Engine brake power produced by mixed biodiesel (C15P15) is slightly lower than the fossil diesel but slightly higher than biodiesel (only palm or coconut). Engine torque produce by the mixed biodiesel is almost the same with the fossil diesel but higher than the others biodiesel blends. Engine brake specific fuel consumption of mixed biodiesel is slightly higher than fossil diesel but lower than others existing biodiesel. It can be reported that the fuel C15P15 showed better performance and can be used as fuel alternative to diesel fuel to reduce the greenhouse gas emission and dependency on crude oil.
Abstract: 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.
Abstract: 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.
Abstract: Crude palm oil (CPO) is currently the most preferable feedstock to be converting into biodiesel via transesterification process in this region. Though the commercial projections for biodiesel have grown, there remains some concerns with respect to its resistance to degradation during storage that possibly will compromise the fuel quality. The purpose of this study is to investigate the influences of ambient temperature condition on properties of biodiesel characteristics and emission. The biodiesel samples were stored and monitored in glass container at the temperature 6°C, 25°C and 30°C, and blending of biodiesel was varied from 5vol% (B5) - 45vol% (B45). The changes of density, kinematic viscosity, flash point, water content, acid value, and as well as emission of CO2 and CO were observed. The result show storage under ambient temperatures properties of CPO biodiesel were found to have higher value compare to the other temperature storage and also have significant effect on the CO emission.
Abstract: Biodiesel is the alternate fuel which is derived from renewable sources either is vegetable oils or animal fats. Biodiesel is non-toxic, have higher biodegradability, free of sulphur, no aromatics and its oxygen content of about 10-11% which is usually not contained in diesel fuel. These characteristics thus predominantly influences to the emissions of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. Purpose of this study is to investigate the effects of oil palm blended fuel, engine speed and test load conditions on the fuel properties, combustion process, combustion characteristics, exhaust emissions and engine performance. The engine speed was varied from 1500 to 3000 rpm, load test condition varied by dynapack chassis dynamometer in 0% ,50% and 100% and blends of 5 (B5), 10 (B10) and 15 vol% (B15) palm oil with the diesel fuel. Increased of blends ratio can improve the combustion process and give less HC and CO emission and almost nearly engine performance. However, this condition tends to produce high NOx production due to higher oxygenated fuel in biodiesel content.
Abstract: This study focuses on the utilization prospect of JatrophaCurcas seed solely as transport sector renewable fuel for producing biodiesel and bioethanol in a parallel system. Diesel (biodiesel) and petrol (bioethanol as petrol additive) engine fuel could be produce from J. Curcas seed oil portion and its’ seed residue, respectively. Ultrasonic-assisted reactive extractions were used for simultaneous oil extraction and esterification/transesterification of J. Curcas seed. The use of acid/alkaline catalyst and ultrasound resulted in a completely de-oiled seed residual by extracting about 50% oil which is equivalent to the Soxhlet extraction performance. The seeds were being chemically and physically characterized with ultimate analyses and TGA for its suitability as bioethanol raw material. Ultimate analyses revealed similarity with other bioconversion feedstock having carbon and oxygen as the major chemical compositions; with slightly lower carbon content in the residuals due to the oil extraction during the in-situ process. However, TG profile exhibited better decomposition of mass in the ultrasonicated residues having easier accessible and better degradable fiber for bioethanol production process. These shown positive effects on the J. Curcasseed pre-treatment during biodiesel reactive extraction process and for further bioconversion toward bioethanol.
Abstract: Globally, the transport sector consumes the biggest share of the fuel supply. Common fuels used in the transport sector are petrol and diesel. Diesel engines have been proven to be more advantageous over gasoline engines, in the aspects of fuel efficiency and engine reliability. The use of diesel passenger cars is very popular in European countries compared to Malaysia. A wider use of diesel-powered cars in Malaysia may benefit the car users, government and the country. The study of the causes of the low percentage of diesel-powered car usage in Malaysia was examined in this present study by using the latest data available in the literature, and by conducting a survey to measure the perceptions and views of the Malaysian public towards diesel-powered passenger cars. Results of this study showed that most of the respondents admitted that diesel engines give more savings. However, respondent perception that diesel-powered cars emit noise and high air pollution of the environment is the main reason Malaysians not choosing diesel-powered cars.