Automotive Technology

International Conference on Automotive Technology An Experimental Study on the Performance and Emission Characteristics of a Single Cylinder Diesel Engine Using CME- Diesel Blends. Hari Vasudevan a*,sandip Mane b, Naresh Deshpande c,ramesh Rajguru d Manuscript received September 30, 2013; revised December 20, 2013 Abstract There has been a worldw ide interest in searching for alternatives to petroleum-derived fuels due to their depletion as well as due to the concern for environmental issues. Vegetable oils have proved their capacity to solve and take care of this problem, because they are renewable and lead to reduction in environmental pollution. In this study, the Performance of a diesel engine on CME and its blend with diesel are compared with diesel. Tests were conducted on a 7.4 kw, computerized single cylinder 4-Stroke stationary diesel engine to evaluate the feasibility of CME and its diesel blends as alternate fuels. The tests were conducted with varying loads. The results have shown that the CME can be used as an alternative fuel compared to mineral diesel. CME blends give somewhat same brake thermal efficiency as compared to conventional diesel. As the amount of CME in the blend increases, the HC, CO and NOx concentrations in the exhaust decreases, when compared with mineral diesel. However this resulted in an increase in the BSFC. This was attributed to the lower calorific value of CME. Keywords: Biodiesel, Coconut Methyl Ester, Diesel blends, Performance, Emissions. 1. Introduction The vegetable oil is found to be a good substitute for diesel because of its attractive properties such as biodegradability, low toxicity, low evaporation, high flash point and reduced emissions. Especially, Vegetable oil is considered as a substitution for diesel in the context of environment related issues. The vegetable oils, which are rich in oxygen, can be used as future alternate fuels for the operation of diesel engine [1]. Biodiesels possesses properties that are very close to diesel after processing and they are renewable by growing crops in rural areas with minimum cost and effort. Existing studies indicate that there are various problems associated with vegetable oils being used as fuels in C I engines, due to its high viscosity, strong tendency to polymerize and bad cold start properties [2]. High viscosity leads to improper atomization of fuel during injection, resulting in incomplete combustion and higher smoke level in the exhaust [3]. The direct use of vegetable oils as a diesel engine fuel is possible but not preferable because of their extremely higher viscosity, strong tendency to polymerize and bad cold start properties. The problem of high viscosity of vegetable oils has been reduced in several ways, such as preheating the oils, blending with other fuels, thermal cracking and transesterification to make biodiesel [4]. The lower iodine value of coconut oil compared to other vegetable oils works favourably for its lower carbon deposits. However there are not many successful experiences reported in literature. Especially deposits on the pistons, valves, combustion chambers and injectors can cause severe loss of output power, engine lubricant deterioration or even catastrophic failure to engines. Some researchers have used COCO oil and its blend with diesel. a Principal D.J. Sanghvi College of Engineering, Mumbai, India b Faculty, Department of Production Engineering, D.J. Sanghvi College of Engineering, Mumbai, India c Faculty, Department of Production Engineering, D.J. Sanghvi College of Engineering, Mumbai, India d Faculty, Department of Mechanical Engineering, D.J. Sanghvi College of Engineering, Mumbai, India * Corresponding Author. Tel: 09821464696, Fax: + 91 (022) 26194988, E-mail: harivasudevan@iitb.ac.in

Hari vasudevan, ICAT 2014, ICAT 10 They have concluded that about 30 % coconut oil-diesels blend has produced higher brake power and net reduction in emissions. And polycyclic aromatic carbons (PAH) above 30 % blend such as 40 and 50% blends developed lower brake power [6]. COCO oil as alternative fuels can be used successfully to operate a direct injection diesel engine without modifications to the engine or the injector system. As the amount of COCO oil increases in the fuel blend, it decreases the BMEP and increases the BSFC. This is attributed to the lower heating value of the coconut oil. COCO oil engine operation has resulted in better emissions, lower smoke and lowers NOx emissions as compared to standard diesel fuel [7]. Researcher used COCO oil directly as an additive to diesel. They concluded that coconut oil could be adapted as an alternative fuel for the existing conventional diesel engines without major modifications. Preheated (50%) coconut oil blends were found to be better in terms of both emission and performance. Without preheating 20%, coconut oil blends gave optimum results, but SFC and emissions were higher than those of preheated blends [8]. Hence pure COCO oil and COCO oil diesel fuel blends can be successfully used in diesel engine as emissions and smoke are lowered [10]. 2. Preparation of Fuel (CME) The coconut oil methyl ester (CME) is prepared by transesterification process. Oil containing less than 4% free fatty acids are filtered and pre-processed to remove water and contaminants and then fed directly to the transesterification process along with any products of the acid esterification process. The catalyst, sodium hydroxide is dissolved in methanol and then mixed with the pre-treated oil. If an acid esterification process is used, then extra base catalyst must be added to neutralize the acid added in that step. Once the reaction is complete, the major co-products, biodiesel and glycerine are separated into two layers. After esterification process is completed, the solution contains methyl ester of respective oil with glycerol and alcohol. The solution is poured into the separating funnel and kept in it for 24 hours. After 24 hour two respective layers of methyl ester and glycerol can be seen in the funnel. The upper layer being the methyl ester of respective oil and the bottom layer is the glycerol. Glycerol can be drained from the tap and what remains is the biodiesel. Once separated from the glycerine, the biodiesel goes through a clean-up or purification process to remove excess alcohol, residual catalyst and soaps.. This is further tested and properties are listed in table I below. It is then dried and sent to storage. Sometimes the biodiesel goes through an additional distillation step to produce a colorless, odorless and zero sulphur biodiesel. Table I. Properties of Diesel and CME Property (8 pt) Diesel CME Viscosity (cm/s 2 ) 4.0 5.48 Density (kg/m 3 ) 830 890 Flash Point ( C) Acid Number 50 0.2 140 0.3 3. Experimentation The engine used is single cylinder, Water-cooled, Vertical, 4 stroke cycle, direct injection, naturally aspirated diesel engine. The specification of the engine as listed in table II and experimental set up as per figure 1The engine is directly coupled to an eddy current dynamometer. The load on the engine can be varied by opening the torque control knob. Experiments were conducted with pure diesel, pure CME and with the blends of CME-diesel as per the details given in table III. The blends are prepared in volume at different proportions. Smoke density and NO x emissions were measured using AVL smoke meter and exhaust gas analyzer respectively. Table II. Engine Specification Make Kirloskar Engine Single Cylinder 4-Stroke Diesel Engine Rated power 7.4 KW@ 1500rpm Cylinder diameter 102 mm Stroke length 116 mm Compression ratio 17.5:1 Length of arm 180 mm Loading Eddy Current Dynamometer

Hari vasudevan, ICAT 2014, ICAT 2014 10 Table.III. Percentage of Fuel Bend Fuel D 100 B 20 B 60 B100 Fuel Blend 100% Diesel 20% CME,80% Diesel 60% CME,40% Diesel 100% CME Fig. 1.Experimental setup. 4. Result and Discussion The performance and emission graphs of the engine are shown in Figures 2 to 9. Fig. 2.Variation of Brake Thermal Efficiency with Load Fig 2 shows the engine performance at various load provided, such as 0 N-m to 45 N-m. As the load increases, the Brake thermal efficiency increases. It was observed that all the CME blends gives similar Brake thermal efficiency as the conventional diesel. Brake thermal efficiency (BTE) of diesel is higher than CME blends. As the blends increase the BTE decreases. Still the efficiencies are comparable with that of diesel. Fig. 3.Variation of Brake specific Fuel consumption with Load

Hari vasudevan, ICAT 2014, ICAT 10 Fig. 3 shows variation of brake specific fuel consumption with Load. Specific fuel consumption increases with increasing CME in blends. It is clear that the BSFC decreases as the load increases. BSFC for the B100 is higher than B60, B20 and diesel. This is mainly due to fuel specific gravity, viscosity and calorific value. As a result, more CME blends are needed to produce the same amount of energy due to its higher specific gravity and lower calorific value in comparison to conventional diesel. Fig. 4.Variation of Exhaust Temperature with Load Fig. 4 shows variation of exhaust temperature with load. Exhaust temperature depends on the load on the engine. At a low load, exhaust temperature is less and vice versa. Exhaust temperature of each fuel followed some common nature. The exhaust temperature for the diesel is higher than CME blends. Calorific value of diesel is higher than the CME blends and hence more energy is produced and higher temperature generated. Fig. 5.Variation of A/F Ratio with Load Fig. 5 shows that variation of A/F ratio with load. As the load increases, more fuel will be required by the engine according to the load but the amount of change in air is negligible. Therefore A/F ratio decreases when load is increasing. The A/F ratio for diesel is higher than CME blends, this is because of higher calorific value of diesel fuel. Fig. 6.Variation of NOx emissions with Load.

Hari vasudevan, ICAT 2014, ICAT 2014 10 Fig. 7.Variation of HC emissions with Load Fig. 8.Variation of CO emission with Load Fig. 9.Variation of CO2 emission with Load Fig. 6 shows the variation of NOx emissions with load. The temperature combustion of CME blend is the main reason for reduction in NOx. The production of lower combustion temperature by CME is due to their chemical bond and its properties and the calorific value of CME is lower than in the case of diesel. Therefore total heat developed is comparatively low and maximum reduction in NOx. It was observed that maximum 10.9 % NOx concentration is reduced by 100% CME blend and with 18 % reduction in exhaust temperature. Fig. 7 & Fig. 8 shows variation of HC & CO emissions with Load. It is observed that exhaust emissions such as HC, CO are reduced with increasing CME in blends. As the percentage of CME in blend increases, there is reduction of HC and CO emissions. CME contains oxygen molecule and due to this, complete combustion take place.

Hari vasudevan, ICAT 2014, ICAT 10 Fig. 9 shows variation of CO2 emissions with Load. CO2 emissions increases with increase in load. At full load, CO2 emissions are higher. From graph, it is clear that CME blends produce higher CO2 emission than diesel fuel. It is observed that due to O2 content in CME blends, CO2 increases with increasing CME in blend. 5. Conclusion 1. CME is a promising & eco-friendly alternative fuel for use in diesel engine. 2. NOx concentration is reduced by 100% CME blend and with 18 % reduction in exhaust temperature. Results obtained from CME on performance parameters and emission parameters are comparable with that of diesel & is better to some extent. 3. The Properties of CME blends are area comparable with those of conventional diesel. 4. CME can be adopted as an alternative fuel to the existing conventional fuels. 5. CME blended fuels produce similar brake thermal efficiency as conventional diesel. 6. BSFC increases with increasing CME in CME blends. 7. Exhaust emission reduces with increasing CME blends except CO 2. It is observed that the maximum 10.9 % NOx concentration is reduced by 100% CME blend with 18% reduction in exhaust temperature.. 8. It also replaces the exhaust odor of petroleum diesel with a more pleasant smell of popcorn or french fries. References [1] Senthil Kumar, M. Ramesh, Nagalingam B. 2001. Experimental investigations on jatropha oil Methanol dual fuel in CI engine. SAE 2001-01-0153. pp. 1-7. [2] K. Pramanik. 2003. Properties and use of jatropha curcas oil and diesel fuel blends in compression ignition engine. Renewable Energy. 28: 239-248. [3] Ramadhas A. S., Jay raj S., Muraleedharan C. 2005. Performance and emission evaluation diesel engine fueled with methyl esters of rubber seed oil. Renewable Energy. 30: 1789-2000. [4] Masjuki H., M. Z. Abdulmuin. 1995. Investigations on preheated palm oil methyl ester in the diesel engine. Proc.of Mechanical engineers. pp 131-138. [5] Nwafor O. M. I., Rice G. 1996. Performance of rape seed oil blends in diesel engine. Applied Energy. 54: 345-354. [6] Kalam M.A. et al., Exhaust emission and combustion evaluation of coconut oil- powered indirect injection diesel engine Renewable energy 28(2003) 2405-2415. [7] Machacona H.T.C. et al., Performance and emission characteristics of a diesel engine fueled with coconut oil diesel fuel blend Biomass & Bioenergy 20 (2001) 63-69