Combustion parameters of spark ignition engine using waste potato bioethanol and gasoline blended fuels

Transcription

1 IOP Conference Series: Materials Science and Engineering PAPER OPEN ACCESS Combustion parameters of spark ignition engine using waste potato bioethanol and gasoline blended fuels To cite this article: B Ghobadian et al 2015 IOP Conf. Ser.: Mater. Sci. Eng Related content - Sugar beet, bioethanol, and climate change Jens Carl Streibie, C Ritz, C B Pipper et al. - An assessment of combustion products of spark ignition engines supplied by ethanol - gasoline blends K Uzuneanu and E Golgotiu - Simulation of Aldehyde Emissions from an Ethanol Fueled Spark Ignition Engine and Comparison with FTIR Measurements Paola Helena Barros Zaránte and Jose Ricardo Sodre View the article online for updates and enhancements. This content was downloaded from IP address on 23/07/2018 at 07:02

2 Combustion parameters of spark ignition engine using waste potato bioethanol and gasoline blended fuels B Ghobadian 1, G Najafi 1, M Abasian 1 and R Mamat 2 1 Faculty of Biosystem Engineering, Tarbiat Modares University, Tehran, Iran 2 Faculty of Mechanical Engineering, Universiti Malaysia Pahang, Pekan, Pahang, Malaysia rizalman@ump.edu.my Abstract. The purpose of this study is to investigate the combustion parameters of a SI engine operating on bioethanol-gasoline blends (E0-E20: 20% bioethanol and 80% gasoline by volume). A reactor was designed, fabricated and evaluated for bioethanol production from potato wastes. The results showed that increasing the bioethanol content in the blend fuel will decrease the heating value of the blended fuel and increase the octane number. Combustion parameters were evaluated and analyzed at different engine speeds and loads ( rpm). The results revealed that using bioethanol-gasoline blended fuels will increase the cylinder pressure and its 1 st and 2 nd derivatives (P(θ), P (θ) and P (θ)). Moreover, using bioethanolgasoline blends will increase the heat release (Q (θ)) and worked of the cycle. This improvement was due to the high oxygen percentage in the ethanol. 1. Introduction The SI engines are widely utilized due to its reliable operation and economy. As the petroleum reserves are depleting at a faster rate, an urgent need for a renewable alternative fuel arise. Also the threat of global warming and the stringent government regulation made the engine manufacturers and the consumers to follow the emission norms to save the environment from pollution. Among the many alternative fuels, bioethanol is considered as a most desirable fuel extender and fuel additive due to its high oxygen content and renewable in nature [1]. Using gasoline-ethanol blend fuel in SI engines caused higher engine performance and lower emissions than gasoline fuel [2]. According to Yücesu, Sozen [3], using ethanolgasoline blend fuel in a spark ignition (SI) engine caused a higher engine torque than that of gasoline fuel. The maximum torque was obtained at 0.9 relative airfuel ratios. The effects of ethanolgasoline blends (E0, E10, E20, E40 and E60) on engine exhaust emissions and performance has been investigated by Yücesu, Topgül [4]. According to the results of the experiment, engine torque increased. It was also reported that blends with ethanol allowed the compression ratio to increase without any knock [5]. Celik [6] reported that the most suitable ethanolgasoline fuel blend in terms of performance and emissions was E50 in a small gasoline engine with low efficiency. Engine power increased by about 29% running with E50 fuel at high compression ratio compared to running with E0 fuel. The specific fuel consumption was reduced by approximately 3% [6, 7]. With increasing the ethanol content in gasoline fuel, the heating value of the blended fuels is decreased, while the octane number of the blended fuels increases. Al Hasan [8] reported that blending unleaded gasoline with ethanol increases the brake power, torque, volumetric and brake thermal efficiencies and fuel Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by Ltd 1

3 consumption, while it decreases the brake specific fuel consumption (bsfc; the same conclusions can be reached from [9, 10]. The 20 vol.% ethanol in fuel blend gave the best results for all measured parameters at all engine speeds [8]. Using E40 and E60 blends led to a significant reduction of CO and HC emissions [4]. For E50, the CO, CO 2, and HC emissions were reduced by 53%, 10% and 12%, respectively [6, 7]. NOx emission depends on the engine operating condition rather than the ethanol content [11]. NOx concentrations are increased due to rising of the cylinder temperature with increasing ethanol percentage in the blends [9]. The effect of ethanol blended gasoline fuels on emissions was investigated in a spark-ignition engine with an electronic fuel injection (EFI) system [10]. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol is reported to be an important contributor to decreased engine-out regulated emissions and decreased brake specific energy consumption [10]. Wu et al. [12] reported that using E10 blended fuel at a relative airfuel ratio (k) slightly greater than one can generally reduce pollutant emission components. The effects of using ethanol-unleaded gasoline blends on cyclic variability and emissions in a spark-ignited engine have been investigated by Cevis [13]. It was reported that using ethanol-unleaded gasoline blends as a fuel decreased the coefficient of variation in indicated mean effective pressure. The 10 vol.% ethanol in fuel blend gave the best results [13]. 2. Experimental Set Up 2.1. Design of Experiment The combustion parameters from the engine running on bioethanol (derived from potato waste) and blended with gasoline (E5, E10, E15 and E20) were evaluated and compared with gasoline fuel. The properties of ethanol fuel investigated and it has been proved that all specifications are in the standard range based on the ASTM standard. Above 20% ethanol, engine could not run smoothly, therefore, only experimental results obtained up to this percentage of bioethanol will be presented. The fuel blends were prepared just before starting the experiment to ensure that the fuel mixture was homogenous and to avoid the reaction of ethanol with water. A series of experiments were carried out using gasoline, and the various bioethanol blends. All the blends were tested under varying engine speed conditions. The engine was started using gasoline fuel and it was operated until it reached the steady state condition. The engine speed, fuel consumption, and load were measured. After the engine reached the stabilized working condition, combustion parameters were measured. All experiments have been carried out at full throttle setting. To adjust ignition timing, electronic ignition system was used. Before obtaining data from the engine operated with a new blended fuel, the engine was operated using the new fuel for sufficient time to clean out the remaining fuel from the previous blend. Fuel properties were determined at the laboratories of Research Institute of Petroleum Industry (RIPI) in Iran. In this paper, the quantity EX represents a blend consisting of X% bioethanol by volume, e.g., E5 indicates a blend consisting of 5% ethanol in 95% gasoline. Five test fuels were used in this study: 0% ethanol (E0); 5% ethanol (E5); 10% ethanol (E10); 15% ethanol (E15); and 20% ethanol (E20). In this study, the experiments were performed on four cylinder, four-stroke, and spark-ignition (SI) gasoline engine. A 190 kw SCHENCK-WT190 eddy current dynamometer was used in the experiments. Fuel consumption rate was measured in the range of kg/h by using laminar type flow meter, Pierburg model. Air consumption was measured using an air flow meter. Five separate fuel tanks were fitted to the gasoline engine and these contained gasoline and the bioethanolgasoline blends. The engine control unit (ECU) that was used in this engine was a Johnson Controls JCAE S2000. ECU function is to control the quantity of fuel, injection timing, ignition timing and engine speed by receiving signals from seven sensors. These sensors are oxygen sensor, knock sensor, manifold air pressure sensor, intake air temperature sensor, throttle position sensor, water temperature sensor and engine speed sensor. A multipoint fuel injection (MPFI) system with top-feed injectors is used to inject the fuel into the combustion chamber. The ignition system was semi-static distributor 2

4 less ignition (DLI). A schematic diagram and real of the experimental setup is shown in figure 1. A reactor was designed, fabricated and evaluated for bioethanol production from potato wastes (figure 2). To save the cost and energy for bioethanol production, a continuous solid fermentation system has been developed and by using of this system bioethanol was produced from potato wastes. The basic step for production of bioethanol is fermentation of sugars (figure 2). The purity of bioethanol from this machine was measured around 99% that is suitable for blend with gasoline fuel. (a) Figure 1. Engine test set-up and test instruments (a) real and (b) schematic. (b) 3. Results and Discussion Figure 3 shows the effect of various fuels on engine cylinder pressure. When the bioethanol content in the blended fuel is increased, the engine cylinder pressure slightly increased for all engine speeds. The gain of the cylinder pressure can be attributed to the increase of the indicated mean effective pressure for higher ethanol content blends [9]. The heat of evaporation of ethanol is higher than that gasoline, this provides fuelair charge cooling and increases the density of the charge, and thus higher power output is obtained [6]. With the increase in bioethanol percentage, the density of the mixture and the engine volumetric efficiency increases and this causes the increase of power [8]. Under time domain analysis various operations are performed on digital time history records of the signals in the time domain itself to yield information on rates, commencement, duration and end of events, and identification of different phases of any process. This kind of analysis often required some intermediate stages of data processing. In this paper, analysis of combustion parameters in a SI engine which has been performed in the time domain yielded the followings: estimates of cylinder pressure derivatives, estimates for start of injection and ignition delay, estimates of the duration of fuel injection along with the start of dynamic fuel injection, estimates of the heat release descriptors, identification of the phases of combustion and estimates of their duration, identification of the phases of liner vibrations vis-à-vis their origin. The derived parameters identified combustion parameters are peak cylinder pressure [Pc]max, maximum rate of cylinder pressure rise [P c]max, maximum acceleration of cylinder pressure [P c]max, peak rate of heat release [Q ]max which have been investigated in this paper. Figure 4 and 5 show the influence of different bioethanolgasoline blended fuels on rate of cylinder pressure rise [P c]max and maximum acceleration of cylinder pressure [P c]max. The increase of bioethanol content increases the rate of cylinder pressure rise and 3

5 3rd International Conference of Mechanical Engineering Research (ICMER 2015) maximum acceleration of cylinder pressure. Added bioethanol produces lean mixtures that increase the relative air fuel ratio (k) to a higher value and makes the burning more efficient [11]. The improved antiknock behavior (due to the addition of ethanol, which raises the octane number) allowed a more advanced timing those results in higher combustion pressure and thus higher pressure [7]. Hydrolyze Fermentation Bioethanol Bioethanol+ Gasoline blended fuels Figure 2. Bioethanol, gasoline blended fuels preparation process. 4

6 Figure 3. Cylinder pressure for Bioethanol, gasoline blended fuels. Figure 4. First derivation of cylinder pressure for Bioethanol, gasoline blended fuels. For identification of the phases of combustion viz. premixed, mixing controlled and tail end of combustion, their duration and the proportion of the heat release, it was necessary to estimate the rate of heat release and the total heat release. Though the start of combustion could be identified from other p (t) criteria like c p (t) and c, and the end of the mixing controlled phase of combustion (ECC) by p c (t) but the end of premixed phase (ERC) and the end of combustion (EC) could not be identified by any criterion other than the rate of heat-release history. For this purpose an approximate estimate of the rate of heat-release was obtained from the knowledge of measured cylinder pressure history and the cylinder volume change due to piston motion. Disregarding the minor effects of wall heat transfer, blow by and crevice region gas motion, the rate of heat release is given by [2]: 5

7 Figure 5. Second Der. Of Cylinder pressure for Bioethanol, gasoline blended fuels. dq dt 1 p dv c dt 1 1 v dp c dt (1) p where dq/dt is the rate of heat release, kj/s. c is the instantaneous cylinder pressure, kpa, v is the 3 instantaneous cylinder volume, m, is the ratio of specific heat for the air charge ( 1.35). The instantaneous cylinder volume v is given by: where, v v c r c 1 1 R cos R 2 sin 2 rc is the compression ratio, R is the ratio of the length of the connecting rod to the crank radius, 3 v / r 1, m v is the clearance volume, c v 3 s is the swept volume, m, and is the crank angle referred to compression bdc. s c (2) Accordingly, a calculation scheme was developed and typical plots of the rate of heat release are shown in figure 6. Figure 6 show the influence of different bioethanolgasoline blended fuels on rate of heat release. The increase of bioethanol content increases the rate of heat release rise. Effect of bioethanol blending with gasoline fuel on P-V diagram and output work has been indicated in figures 7 and 8. As shown in this figures, the maximum value of these diagrams increases as the ethanol percentage increases. The maximum amount was detected when 20% ethanol was in the fuel blend. As the E% increases in the fuel blend, the indicated work increases (i.e., the indicated efficiency increases). Considering the temperatures for burned and unburned gases (figures 9 and 10) show that the temperature is higher when ethanol percentage increases. It shows that as the percentage of ethanol in the blends increased, gas temperatures were increased. When the combustion process is closer to 6

8 stoichiometric, flame temperature increases, therefore, the gas temperature is increased, due to oxygenated blended fuels and completed combustion [2]. Figure 6. Heat Release for Bioethanol, gasoline blended fuels. Figure 7. P-V diagram for Bioethanol, gasoline blended fuels. 7

9 Figure 8. Work for Bioethanol, gasoline blended fuels. Figure 9. Burned gas temperature for Bioethanol, gasoline blended fuels. 8

10 Figure 10. Unburned gases temperature for Bioethanol, gasoline blended fuels. 4. Conclusions The results revealed that using bioethanol-gasoline blended fuels will increase the cylinder pressure and its increase of bioethanol content increases the rate of cylinder pressure rise and maximum acceleration of cylinder pressure (P(θ), P (θ) and P (θ)). Moreover, using bioethanol-gasoline blends will increase the heat release (Q (θ)) and worked of the cycle. This improvement was due to the high oxygen percentage in the ethanol. Acknowledgements The authors wish to thank the Iranian Fuel Conservation Organization (IFCO) of NIOC for the research grant provided to complete this project and Mega Motor Company for providing of laboratory facilities. References [1] Selvan V A M, Anand R, Udayakumar M 2009 J Eng Appl Sci [2] Najafi G, Ghobadian B, Tavakoli T, Buttsworth D, Yusaf T, Faizollahnejad M 2009 Applied Energy [3] Yücesu H S, Sozen A, Topgül T, Arcaklioğlu E 2007 Applied Thermal Engineering [4] Yücesu H S, Topgül T, Cinar C, Okur M 2006 Applied Thermal Engineering [5] Topgül T, Yücesu H S, Cinar C, Koca A 2006 Renewable energy [6] Celik M B 2008 Applied Thermal Engineering [7] Agarwal A K 2007 Progress in energy and combustion science [8] Al-Hasan M 2003 Energy Conversion and Management [9] Bayraktar H 2005 Renewable Energy [10] He B-Q, Wang J-X, Hao J-M, Yan X-G, Xiao J-H 2003 Atmospheric Environment [11] Hsieh W-D, Chen R-H, Wu T-L, Lin T-H 2002 Atmospheric Environment [12] Wu C-W, Chen R-H, Pu J-Y, Lin T-H 2004 Atmospheric Environment [13] Ceviz M, Yüksel F 2005 Applied Thermal Engineering