Assessing Effects of Idling of a Diesel Engine Operated with Optimized Blend of Palm and Mustard Biodiesel

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1 Assessing Effects of Idling of a Diesel Engine Operated with Optimized Blend of Palm and Mustard Biodiesel S.M. Ashrafur Rahman, Hassan Masjuki, Md. Kalam, M.J. Abedin, A. Sanjid, S. Imtenan, and M.I. Arbab Universiti Malaya Published 04/01/2014 CITATION: Rahman, S., Masjuki, H., Kalam, M., Abedin, M. et al., "Assessing Effects of Idling of a Diesel Engine Operated with Optimized Blend of Palm and Mustard Biodiesel," SAE Technical Paper , 2014, doi: / Copyright 2014 SAE International Abstract Palm is an edible feedstock which is immensely popular in Malaysia as an alternative fuel which can substitute diesel fuel. However, use of Palm biodiesel in diesel engine have a negative effect on food security, thus, in this study authors used Mustard biodiesel, which has poor fuel properties, with Palm biodiesel to produce an optimum blend. This blend will have better fuel properties compared to Mustard biodiesel and will help eliminate dependency of Palm biodiesel. To ensure that optimized blend achieves better fuel properties MATLAB optimization tool was used to find out the optimum blend ratio. Linear relationship among the fuel properties was considered for MATLAB coding. The resultant optimum blend is represented by PM. Optimum blend revealed improved fuel properties compared to mustard biodiesel. Fuel consumption and exhaust emission of diesel engine operated by the produced optimized blend blends at high idling conditions with and without a turbocharger installed, were evaluated. Optimized blend achieved lower CO, HC and NO X emission compared to Mustard biodiesel blends and also improved fuel consumption at idling conditions. When the engine was turbocharged it further decreased CO, HC and fuel consumption, but significantly increased NO X emission. Introduction High idling conditions, during which an engine runs at low load and low rated speed, represent one of the major problems currently facing the transport industry. After driving for a certain period, drivers are advised to take a rest both for their safety and that of other road users. During this time, drivers typically keep the engine idling in order to maintain cab comfort and to cab loads with power, such as heating, air conditioning, refrigeration, and micro wave energy [1, 2, 3, 4, 5, 6]. Studies indicate that long-haul trucks generally idle for between 6 and 16 hours per day [7, 8]. During idling the engine is not able to work at peak operating temperature and thus fuel combustion is incomplete, leaving fuel residues in the exhaust and increasing emission levels [9, 10, 11, 12], also, fuel consumption during idling is a vital concern for the truck industry as this is complete waste. Idling fuel consumption is estimated to be approximately billion gallons per year [13, 14]. Engines run at 30% efficiency (thermal) throughout highway operation, but at only 3-11% efficiency during idling [13]. A study by Argonne National Laboratory indicated that, on average, a heavy-duty truck idles for six hours per day or 1818 hours per year. This idling is equivalent to extra miles of engine wear, burning 3750 gallons of diesel fuel, and adding operational costs of between US$4000 to US$7000 per truck per year. Thus, idling not only increases fuel consumption costs, but also decreases the time interval between oil changes and increases maintenance and repair costs [15, 16]. In the study by Khan et al.[17] increase in NO X emission was found due to an increase in idling speed. During idling, fuel consumption, and both CO and HC emission can also be very high compared to that of conventional diesel [18, 19]. HC emission during idling is reported to be 1 to 5 times greater than that during the driving cycle, while idling CO emissions were found to be 5%-75% of driving cycle levels [20]. Brodrick et al. [19] observed that an increase in idling speed from 600 to 1050 rpm resulted in increased emission of NO X and CO by around 53% and 460%, respectively, with fuel consumption also increasing by 70%. Lim [21] reported that an increase in idling speed doubled fuel consumption, while Shida and Munn found idling HC and NO X emissions to be 72% and 29%, respectively, of those of the WVU 5 mile test [22]. Transport sector heavily depends upon diesel fuel due to their high adaptability, high combustion efficiency, availability, reliability as well as the handling facilities. However, emissions which are produced from burning diesel fuel have a serious effect on both the environment as well as human health [23, 24, 25]. These factors have promoted the search for alternative fuels that can ensure clean combustion [26, 27, 28]. Biodiesel is one of the appropriate alternatives of diesel fuel which is renewable, biodegradable, non-toxic, emits less compared to

2 pure diesel [29, 30]. It has similar functional properties as diesel fuel [31]. Palm oil is widely used in Malaysia which is an edible feedstock. Use of palm biodiesel in diesel engine will hamper food security. So, in-order-to deviate the dependency on Palm oil, the authors looked for another feedstock, which can be used with the palm biodiesel, so that, use of palm biodiesel can be minimized a little bit. In this study, thus Mustard biodiesel was also used to produce an optimized blend that can be used to operate diesel engine. 20% blend of developed optimized biodiesel with petroleum diesel has been used to investigate their effect on fuel consumption and emission characteristics compared at high idling conditions. was produced using the blend ratio (Palm 23.1% and Mustard 76.9%) to compare with the optimum blended biodiesel and is denoted as MP. Table 3. Boundary conditions and optimum blending ratio derived using MATLAB 1. Optimizing Fuel Properties For the optimization process, linear relationship among the fuel properties has been considered to find out the optimum blending ratio. To figure out optimum blending ratio, Matlab optimization tool has been used. At first, few boundary conditions were considered, upper and lower limit for a specific fuel property was considered according to the highest and lowest value of that property of the individual fuel, present in the blend and also the ASTM standard. In this experiment, new type of biodiesel were produced by blending Palm and Mustard biodiesel. Apparatus used to measure the fuel properties are listed in table 1, and the measured fuel properties are listed in table 2. Then, MATLAB code was developed considering linear relationship to find the optimum blend. Table 1. Summary of the equipment used to measure the properties. Table 2. Experimentally investigated individual fuel properties. Table 4. Experimental blended fuel properties 2. Engine Test An in-line four cylinder CI engine was used in this experiment; its specifications are summarized in Table 5. A schematic diagram of the engine test bed is shown in Figure 1. During the first step the engine was warmed for 5 minutes in order to avoid emission fluctuations. Tests were then carried out under three different high idling modes: Mode 1 (1000 RPM and 10% load), Mode 2 (1000 RPM and 15% Load), and Mode 3 (1200 RPM and 10% Load). These tests were conducted two ways: with and without turbocharger installed. Loads were measured via a dynamometer; Table 6 lists all equipment used in the experiment. During the fuel consumption and exhaust emission tests, every fuel sample was tested three times, with the average results reported here. The engine was connected to both the test bed and a computer data acquisition system, the data acquisition board being employed for signal collection, rectification, filtering and conversion to enable the data to be read. The data acquisition board was connected to a laptop from which the user can monitor, control and analyze the data using software and a REO-dCA controller. The boundary conditions used for MATLAB optimization are listed in table 3. The table also contains, the resultant blend ratio. Finally, the optimum blend were prepared using the resultant blend ratio and the properties of the optimum blend were tested in the laboratory (table 4). Also, another fuel blend Figure 1. Schematic diagram of experimental setup.

3 Table 5. Engine Specification Table 6. Equipments used in emission test 3. Result and Discussion The comparison of the theoretical and experimental blended fuel properties are given in figure 2. From the figure it is seen that the deviations of density, viscosity are higher by % for PM and.5-1.3% for MP blends, whereas Calorific value, Flash point, Cetane number are lower by % for PM and % lower for MP blends. Fig 4 depicts fuel consumption of the fuel samples that were used to operate the diesel engine. From the fig 4 it can be seen that, with the use of turbo-charger, PM20 consumes % less fuel whereas MP20 consumes only % less fuel compared to MB20. The decrease in fuel consumption may be due to the better fuel atomization resulted due to mixing of Palm biodiesel with Mustard biodiesel. Also, optimized blend, showed better fuel consumption due to ensuring better fuel atomization. With the introduction of turbocharger, PM20 decreased fuel consumption by 23-36% whereas MP20 only decreased fuel consumption by 14-16% compared to MB20. From the fig 4 it also can be seen that, when load is increased, fuel consumption increases, and furthermore when idling speed is increased fuel consumption also increases. This is also supported by Lim [21], when engine is idling at a faster speed, fuel consumption will be higher due to increase in fuel injection rate per second. Further reduction due to use of turbocharger is mainly caused by the improvement in fuel atomization, air-fuel mixing and combustion characteristics of the fuel due to the high air temperature and increased air charge in the cylinder of the diesel engine. Figure 4. Fuel consumption of Biodiesel blends Figure 2. Percentage (%) of variation between theoretical and experimental blended fuel properties Figure 5. CO emission of Biodiesel blends Figure 3. NO X emission of Biodiesel blends

4 Figure 6. HC emission of Biodiesel blends Figure 3 compares NO X emission of optimized blend PM20 with MB20, PB20 and MP20 at idling condition. From the figure it can be seen that, emission increased by % compared to MB20 without turbocharger, whereas, though introduction of turbocharger increases NO X emissions, optimized blend shows an increase of 2.65% with the turbocharger. Turbocharger improves fuel atomization, results in better combustion and produces higher in-cylinder temperature, which in turns increases the NO X emissions [32]. However, increase in idling speed or load, decreases emissions, as at elevated speed or load, ignition delay gets shorter, and time of the blends being at elevated temperature decreases. As a result emission decreases. Fig 5 and 6 shows the CO and HC emissions of optimized blend compared to MB20, PB20 and MP20. Compared to MB20, CO emissions were less % (without turbocharger) and % (with turbocharger). So, Introduction of turbocharger has slightly negative impact on the optimized blend. MP20 emitted higher CO at all conditions compared to PM20 however emitted less compared to MB20. Compared to MB20, HC emissions were lowered by % without turbo charger installed and % less with turbocharger installed. The application of turbocharger provides increased air to the diesel engine and enables mixing of fuel-air easily in the combustion chamber, thereby causing better combustion and lower CO and HC emission values. Optimized blend also have better density and viscosity compared to Mustard biodiesel, which is the reason behind decrease in these emission parameters. Increase in idling speed or load, decreases emission for the biodiesel blends. This is due to the reason that, increase in speed ensures better combustion. 4. Conclusion From the experiment, it is clearly evident that, optimized blend shows better performance compared to mustard biodiesel at idling conditions. The results obtained from this study may be summarized as follows. Fuel properties of mustard biodiesel is improved by blending with other biodiesel at optimum blend ratio. Fuel consumption of optimized blend decreased by 20-24% without the introduction of turbocharger compared to mustard biodiesel blend. For optimized blend, CO emission decreased by %, HC emission decreased by %, NO X emission decreased by % compared to mustard biodiesel, without turbocharger installed Introduction of Turbocharger reduces fuel consumption by improving fuel atomization, air-fuel mixing and combustion characteristics of the fuel due to high air temperature and increased air charge in the cylinder. As turbocharger ensure better combustion, CO and HC emission reduces. Turbocharger increases the combustion chamber temperature which results in higher NO X emission. Fuel consumption of optimized blend decreased by % compared mustard biodiesel, with turbocharger installed. For optimized blend, CO emission decreased by %, HC emission decreased by 16-26%, NO X emission decreased by % compared to mustard biodiesel, with turbocharger installed. Nomenclature PB - Palm Biodiesel MB - Mustard Biodiesel PM20-20% PM (optimized blend)+80% diesel HC - Hydrocarbons CO - Carbon Monoxides NO X - Nitrogen oxides NA - Without Any Turbocharger TU - With turbocharger installed g/h - gram per hour lt/hr - litres per hour MP - a blend produced by blending Mustard and Palm biodiesel References 1. Goel, A. and Rousseau L.-M., Truck driver scheduling in Canada. Journal of Scheduling, (6): p Goel, A., The Canadian minimum duration truck driver scheduling problem. Computers & Operations Research, (10): p Langrish, J.P., et al., Reducing personal exposure to particulate air pollution improves cardiovascular health in patients with coronary heart disease. Environmental health perspectives, (3): p Kabir, Z., Bennett K., and Clancy L., Lung cancer and urban air-pollution in Dublin: a temporal association? Instructions for Authors, (7). 5. Yorifuji, T., et al., Long-term exposure to traffic-related air pollution and the risk of death from hemorrhagic stroke and lung cancer in Shizuoka, Japan. Science of The Total Environment, : p Jinping, T., et al., Assessment of industrial metabolisms of sulfur in a Chinese fine chemical industrial park. Journal of Cleaner Production, 2012.

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