Experimental Investigations on the Engine Performance and Emission Characteristics of Indirect Injection (IDI) Diesel Engine using Preheated Jatropha Methyl Ester as Alternate Fuel

Experimental Investigations on the Engine Performance and Emission Characteristics of Indirect Injection (IDI) Diesel Engine using Preheated Jatropha Methyl Ester as Alternate Fuel

1Y. Ashok Kumar Reddy

Mechanical Engineering

NBKR Institute of science and Technology Vidyanagar- 524413.

NELLORE District

2B. V. Appa Rao

Marine Engineering A.U.College of Engineering(Autonomous),

Vishakapatnam-530003.

Abstract Biodiesel is renewable fuel which can reduce the use of petroleum based fuels which is known for lesser green house gas emissions of internal combustion engines. Therefore, to reduce emissions, researchers have focused their interest in the area of biodiesel as an alternative fuel for diesel engine. Investigations have shown that blending of biodiesel with diesel up to 20% by volume has good performance and emission (based on NO limitation) characteristics in CI engines. Further increase of biodiesel fraction will increase the viscosity of the injected oil, decrease the performance and increase emissions like NO because biodiesel is an oxygenated fuel. Higher viscosity fuel injection means retarded fuel spray diffusion and lower air entrainment characteristic. This is the reason that change over has been mooted to IDI engines because of better and complete combustion in both the chambers even there is certain compromise on the quality of the fuel. The two combustion chambers of IDI engine (tested now) are connected by an orifice and not a nozzle as was conventionally defined. To increase the fraction of the biodiesel or to replace the conventional diesel fuel by biodiesel it is required to reduce the viscosity to restore or enhance the functioning of the engine. In the present work an experimental investigation is carried out on a four stroke single cylinder IDI engine to find out the performance and emission characteristics with the preheated Jatropha Methyl Ester (JME) with the viscosity4.36cSt. JME is preheated at 60,70,80,90 and 1000 C temperatures using online electronic preheating system. Experiments were done using diesel, biodiesel and biodiesel at different preheated temperatures and for different engine loading conditions keeping speed constant at 1500rpm. Improvement in performance and emission characteristics is obtained with biodiesel preheated to 600C and showed increase in break thermal efficiency over unheated biodiesel at 2.7kW load.

Keywords Transesterification, preheating, Jatropha biodiesel, IDI engine.

1. INTRODUCTION

   Due to the depletion of the worlds petroleum reserves and the increasing environmental

   concerns, it become more obvious the world is going to need to consider alternative fuels.

   The total estimated world greenhouse gas (GHG) emissions in the year 2005 amounted to 44 billion tonnes of CO equivalent, of which 66.5% were associated with energy services. Of the total emissions, the share from transportation, electricity and heating was 39.2% corresponding to 59% of the emissions related to energy services [1]. Much research has been done to investigate the use of vegetable oils derived from biomass sources as a fuel for automotive engines. Biodiesel is a good promising alternative to petro diesel. It is renewable, nontoxic and can be produced locally from agriculture and plant resources. Biodiesel is a form of biomass particularly produced from vegetables oils, has recently been considered as the best candidate for a diesel fuel substitution. Jatropha curcas L. is non-edible oil being singled out for large-scale plantation on waste lands. Jatropha plant can thrive under adverse conditions. It is a drought- resistant plant, living up to fifty years and has capability to grow on marginal soils. It requires very little irrigation and grows in all types of soils (from coast line to hill slopes). The oil content of jatropha seed ranges from 30% to 40% by weight and the kernel itself ranges from 45% to 60%. Fresh jatropha oil Slow-drying, odor less and colour less oil, but it turns yellow after aging

   .Pramanik tried to reduce viscosity of jatropha oil by heating it and also blending it with mineral diesel [2]. Acceptable thermal efficiencies of the engine had obtained with blends containing up to 50% of Agarwal et al. observed that engine operated on jatropha oil (pre heated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentration..However, for higher blend concentrations, performance and emissions were

   observed to be marginally inferior [3]. The use of biodiesel fuel showed reasonably good performance and the use of 100% esterified jatropha oil gave reduction in NOx levels, increase in smoke while maintaining almost same fuel consumption values with 100% diesel fuel operation [4].

   The oil contains primarily six fatty acids viz.Myristic, palmitc, stearic, Oleic, Linoleic, and Arachidic.Raw Jatropha oil has high viscosity and poor combustion characteristics which cause poor atomization, fuel injector blockage, and excessive engine deposit and engine oil contamination. In India the prohibitive cost of edible oils prevents their use in biodiesel preparation, but non-edible oils are affordable for biodiesel production. McDonald et al. [5] investigated soybean oil methyl ester as a fuel on a caterpillar indirect injection diesel engine and found that overall combustion characteristics were quite similar as for diesel except shorter ignition delay for soybean methyl ester. Kumar et al. [6] found that for Jatropha oil methyl ester, ignition delay was higher as compared to ignition delay for diesel as a fuel on a constant speed diesel engine.Selim et al. [7] tested jojoba oil methyl ester as a fuel on Ricardo compression swirl diesel engine and found that the pressures and pressure rise rates for jojoba oil methyl ester are almost similar to that as gas oil. jojoba oil methyl ester, however, exhibits slightly lower pressure rise rate than gas oil, and jojoba oil methyl ester seems to have slightly delayed combustion. Vander Walt and Hugo [8] used the sunflower oil in direct and indirect injection diesel engines. In that study, indirect injection (IDI) diesel engines showed no adverse effects when sunflower oil was used for over 2000h.But, direct injected engines showed that the power loss due to severely coked injectors, carbon build-up in the combustion chamber, and stuck piston rings. Hawkins et al. [9] reported similar findings for indirect and direct injection diesel engines using sunflower oildiesel fuel blend (20:80 v/v %). They explained that injector coking was the problem by using sunflower oil in the direct injection (DI) diesel engines. Although the mentioned engine problems were generally related to the direct usage of vegetable oils, sometimes successful results were obtained for long -term usage.Karaosmanogluet al. [10, 11]used the sunflower oil for 50 h in a direct injection diesel engine (Pancar Motor E-108). The researchers did not see any significant differences in the power and fuel consumption, and did not find any engine problems during the tests. In the same engine, O¨ zektasx [12]investigated the effect of used sunflower oilsdiesel fuel blend (20:80 v/v %) on the engine characteristics and exhaust emissions. The NOx emission of the fuel blend was found considerably lower (62%) than that of No. 2 diesel fuel at low engine speeds, but the difference diminished with the increasing engine speed. The researchers [1316]saw that the preheating method is effective and practicable without any modifications on the diesel engines for short -term usage of vegetable oils. Cetinkaya [17] investigated he effect of heated sunflower oil and sunflower oildiesel fuel blends on diesel engine performance. The results showed that the sunflower oil and its blends are promising as an alternative diesel fuel for diesel engines. The results of the literature review have indicated that thecombustion characteristics of an IDI diesel engine fuelled

   withpreheated biodiesel (with marginal increase in viscosity over diesel fuel) was not investigated in detail. Itis well known that the IDI diesel engines exhibit two importantadvantages; not depend on fuel quality and produce lowexhaust emissions depending on combustion chamber design. Experiments are conducted on indirect injection diesel (IDI) engine run at constant speed of 1500 rpm running with with neat diesel, pure JME and JME preheated to 60,70,80,90 and 100 degree centigrade respectively .Engine is run at five discrete part load conditions viz. No Load, 0.77 kW, 1.54 kW, 2.31 kW and 2.70 kW keeping in mind performance and emissions. Even though thermal efficiency suffers due to higher combustion surface area and higher compression ratio, there will be betterment in other aspects like crank case oil dilution and lower emissions from the engine. Therefore, the main purpose of thisstudy is to determine the performance and emission characteristics of preheated JME and to compare themwith those of reference petroleum based diesel fuel (PBDF) and unheated JMEunder the identical stable engine speed at 2.70kW load condition. This study has been taken up in conceptualizing the combination of fuel keeping in view lesser or no review of work presented in the literature with the preheated pure biodiesel.

   Table-1 Characterization of fuels used

   S.No	Propertity	Diesel	JME
   1	Viscosity(cSt)	2.41	4.36
   2	Density(kg/m3)	830	875
   3	Cetane number	45	52
   4	Calorific value (kJ/kg)	43000	38468
   5	Boiling temperature(0c)	180- 330	370
   6	Autoignitiontemperature(0c)	235	>300
   7	Latent Heat of Vaporization (MJ/kg)	0.280	0.259

2. EXPERIMENTATION:

   The experimental setup consists of the following equipments:

   1. Single cylinder IDI diesel engine loaded with eddy

   2. current dynamometer

   3. Engine Data Logger (make: APEX INNOVATIONS)

   4. Exhaust gas Analyzer (1600L,German ma German make)

   5. Smoke Analyzer

      Four stroke single cylinder IDI diesel engine details as shown in below and figure.1 is the schematic diagram showing various equipment modules.

      Fig. 1 Schematic arrangements of the engine test bed, Instrumentation and data logging system

      Fig.2 Experimental test rig set up

      The pressure transducer is fixed (flush in type) to the cylinder body (with water cooling adaptor) to record the pressure variations in the combustion chamber. Crank angle encoder sends signals of crank angle with reference to the TDC position on the flywheel and will be transmitting to the data logger. The data logger synthesizes the two signals and final data is presented in the form of a graph on the computer using C7112 software designed by Apex Innovations Pune, India.

      Fuel consumption is measured to calculate BSFC, fuel air ratio and thermal efficiency. Exhaust gas temperatures were also recorded for all loads.

      Delta 1600-L exhaust gas analyzer(German Make) is used to measure CO2, CO, HC, NO in exhaust gases at all loads and graphs are drawn to compare. Fuel consumption is measured to calculate BSFC, fuel air ratio and thermal efficiency. Exhaust gas temperatures were also recorded for all loads.

      Experimental test rig comprising loading device (eddy current dynamometer) and combustion data logger is established in the department of marine engineering, Andhra University. IDI variable speed diesel engine (Bajaj Make) for automobile purpose is chosen.

      Experiments were conducted with neat diesel, pure JME and JME preheated to 60,70,80,90 and 100 degree centigrade respectively .Engine is run at five discrete part load conditions viz. No Load, 0.77 kW, 1.54 kW, 2.31 kW and

      2.70 kW. In this experiment neat JME fuel at different temperatures viz.60, 70, 80, 90 and 100 degree centigrade respectively have been tested to evaluate the neat biodiesel performance

      .Table 4.1 Specifications of the IDI- Diesel Engine.

      Engine manufacturer	Bajaj RE Diesel Engine
      Engine type	Four Stroke, Forced air and Oil Cooled
      No. Cylinders	One
      Bore	86.00mm
      Stroke	77.00mm
      Engine displacement	447.3cc
      Compression ratio	24±1:1
      Maximum net power	5.04 kw @ 3000 rpm
      Maximum net torque	18.7 Nm @ 2200 rpm
      Idling rpm	1250±150 rpm
      Injection Timings	8.50 to 9.50 BTDC
      Injector	Pintle
      Injector Pressure	142 to 148 kg/cm2
      Fuel	High Speed Diesel
      Starting	Electric Start

3. RESULTS AND DISCUSSION

1. Cylinder pressure signature study and Heat Release Rate curves:

   Figre.3 depicts the combustion pressure variation at maximum pressure variation at maximum load operation for the fuel samples appended in the right column.

   • Close observation of the variation of the pressures in figure.3 reveal that biodiesel heated up to 600 C

     attain peak pressure 60.20 bar 3710 of crank angle at 2.70kW load but reaches the position late in the stroke.

   • Biodiesel heated up to 800 C is the next contender which reaches 60 bar at 3690 crank angle at the same load. Diffused combustion in the case of 600 heating is comparatively better than other heated oil operations which can be observed from the rise in the pressure levels after reaching peak pressures. The net heat release rate and cumulative heat release rate envisage better diffused combustion (figures 5 &6) for the heated oil at 600 C.

   • The delay period is increasing by fraction of a degree following the rise in the temperature of the input biodiesel. At 600C of the biodiesel injected, as discussed there is a match of viscosity with the

     diesel fuel and as one increase further the temperature, the viscosity variation is more and the fuel loses its oiliness leading to variation in the latent heat of the oil which finally tells on the combustion of the fuel. This may be the possible reason in the degradation of the combustion with the increase in biodiesel temperature.

     Figure.4 demonstrate delay period of the various samples.Figure.5 gives an idea about the net heat release rate derived with the pressure variation in the main chamber assuming the pressure prevailed at any time in both the chambers are same. Figure 6 represent the derived plot for the cumulative heat of combustion and for the heated biodiesel at 600 C the curve is jacked up indicating better combustion at the load indicated.

     Combustion pressure verses crank angle at 2.70kW for

     various temperatures of JME

     65

     60

     55

     50

     Pressure(bar)

     45

     40

     35

     30

     DIESEL BD

     <>BD 60

     BD 70

     25 BD 80

     20

     15 BD 90

     10

     5

     0

     320 340 360 380 400 420 440

     Crank Angle (deg)

     BD 100

     Fig.3 Combustion pressure variation in shorter duration of crank angle

     Combustion pressure vereses crank angle at 2.70 kW for various temperatures of JME

     65

     60 DIESEL

     55

     Pressure(bar)

     50 BD

     45

     40 BD 60

     35

     30 BD 70

     25 BD 80

     20

     15 BD 90

     10

     5

     0

     320 325 330 335 340 345 350 355 360 365 370

     Crank Angle (deg)

     BD 100

     Fig: 4 Combustion pressure trend to analyze the delay period

     Net Heat Release Rate verses crank angle at 2.70kW for various temperatures of JME

     30

     Heat Release rate (J/degree)

     DIESEL

     25

     20 BD

     15 BD60

     340

     10

     5

     0

     60

     -5 3

     -10

     BD70 BD80 BD90 BD100

     420

     400

     380

     Crank Angle (deg)

     Fig:5 Net heat release rate derived traces.

     Cumulative Heat Release Rate verses crank angle at 2.70 kW for Various Temperatures of JME

     700

     Heat Release Rate (J/Deg)

     600

     500

     400

     300

     200

     100

     0

     330 340 350 360 370 380 390 400 410 420 430

     Crank Angle (Deg)

     DIESEL BD

     BD 60

     BD 70

     BD 80

     BD 90

     BD 100

     Fig.6 Cumulative heat release rate derived traces

2. Engine performance and Emissions:

   • Break Specific Fuel Consumption: The brake specific fuel consumption is increasing with the increase of temperature. Figure 7 illustrates the effect of temperature in modifying the specific fuel consumption. For example at 2.31 kW engine power, the specific fuel consumptions are 0.2754, 0.3039, 0.309, 0.3124, 0.3151, 0.3262 and 0.3232 kg /kW hr starting from diesel fuel to biodiesel oil heated to 1000 C, with prefixed heated oils. Density property variation of JME is the main reason for this change.

   • Break Thermal Efficiency: Figure.8 gives the details of break thermal efficiency verses break power. Thermal efficiency increased to maximum levels at 2.31 kW part load of the engine and the values are as follow: diesel: 30.39%, BD: 30.78%, BD 60:30.28%, BD70: 29.9%, BD80: 29.69%, BD 90: 28.68%, for BD100: 28.9%. There is a decrease of maximum of 1.42% in thermal efficiency of the engine referring to the diesel fuel.

     Exhaust temperatures and smoke levels are presented in figures 9 and 10.There is a trend of the increasing exhaust temperatures with the increase in the bio-fuel temperature at any load chosen. It is observed that there is a difference of 450 C to 700 C in exhaust temperatures scanned at different loads with reference to diesel exhaust temperature. This may be due to the combustion refinement in diffused combustion zone as can be observed in the cumulative heat release rate curves.

     Smoke levels have altogether decreased in general (with reference to diesel fuel) by 15 to 20 HSU at upper part loads as can be seen from the figure 10. Biodiesel normally will generate lower smoke levels as per the research conducted.

     Heating of the oil further reduced the smoke levels by 10 HSU with reference to the neat biodiesel. This is positively an indication of better combustion when the input oil is being heated over biodiesel.

     The figures 11 to 14 envisage tail pipe emissions from the engine. The monitored emissions are HC, CO, NO and CO2.

   • Hydrocarbon emissions are comparatively very much lower in the case of IDI engine for the diesel fuel operation. This reduction is drastic over the DI engine HC emission which is in the range of 40 ppm to 130 ppm in the load range approximately equal to that of IDI engine. Heating further reduced HC levels to 1 ppm from 4ppm which is in the case of neat diesel operation.

   • CO levels in the figure 13 indicate the CO emission level in the case of IDI engine. These vary in between 0.01 to 0.07 % by volume. In the case of DI diesel engine, the range is from 0.09 to 1.7 % by volume for almost the same power range of engine operation.

   • CO emission in the case of heated fuel by 600 C is emitting of 0.01% by vol. which is minimum in the series and thought to be efficient point of fuel heating.

   • CO2 levels have increased decimally with reference to the diesel fuel and there is very small increase in the level in the case of fuel heated to 600C. This may be due to the decrement in the CO emission level owing to better combustion.

   • In the case of NO emission it is an established fact that biodiesel fuel emits more NO because of additional Oxygen content in its molecular structure. Generally all loads the NO emission more for neat biodiesel and heated biodiesel but for

     some occasions where there is insignificant rise in the NO emission especially at lower loads of the engine as plotted in the figure 15. At higher loads on the engine the NO level for the heated oil at 600

     C has decreased from 45ppm. And in general, there is increase in NO levels at lower loads and decrease at higher loads.

     0.55

     0.5

     BSFC (kg/kW-hr)

     0.45

     0.4

     0.35

     0.3

     0.25

     0.2

     BSFC verses Break Power

     0.5 1 1.5 2 2.5 3

     Break Power (kW)

     DIESEL BD BD60 BD70 BD80 BD90 BD100

     Fig.7 BSFC Vs Brake power.

     Break thermal efficiency verses break Power

     33

     30.28

     30

     27.69

     Break Thermal

     Efficiency (%)

     27

     Diesel

     30.11

     BD

     BD60

     24 BD70

     21 BD80

     19.78

     BD90

     18

     BD100

     15

     0.5 1 1.5 2 2.5 3

     Break Power (kW)

     Fig.8 Thermal efficiency Vs Brake power.

     Exhaust Gas Temperatue verses Load

     375 Diesel

     Exhaust Gas Temperature(c)

     325 BD

     275

     225

     BD 60

     BD 70

     175

     BD 80

     125

     75

     0 0.5 1 1.5 2 2.5 3

     Load(kW)

     BD 90

     BD 100

     Fig.9 Exhaust Gas Temperature Vs Load with various temperatures of JME

     Smoke verses Load

     65

     60

     Smoke (ppm)

     55

     50

     45

     40

     35

     30

     0 0.5 1 1.5 2 2.5 3

     Load (kW)

     Diesel BD BD60 BD70 BD80 BD90 BD100

     Fig.10 Smoke Vs Load with various temperatures of JME.

     Hydro Carbons verses Load

     12

     10

     8

     Diesel BD BD60

     HC (ppm)

     6 BD70

     4 BD80

     2

     0

     0 0.5 1 1.5 2 2.5 3

     Load (kW)

     BD90 BD100

     Fig.11 Hydro carbons Vs Load with various temperatures of JME.

     Carbon Monaxide verses Load

     0.09

     0.08

     0.07

     0.06

     CO (%)

     0.05

     0.04

     0.03

     0.02

     0.01

     0

     0 0.5 1 1.5 2 2.5 3

     Load (kW)

     Diesel BD BD60 BD70 BD80 BD90 BD100

     Fig.12 Carbon monoxide Vs Load with various temperatures of JME.

     Carbon Dioxide verses Load

     12

     Diesel

     10 BD

     BD60

     CO (%)

     8

     BD70

     6

     BD80

     4 BD90

     BD100

     2

     0 0.5 1 1.5 2 2.5 3

     Load (kW)

     Fig.13 Carbon Dioxide Vs Load with various temperatures of JME.

     350

     300

     250

     NO (ppm)

     200

     150

     100

     50

     0

     NO verses Load

     0 0.5 1 1.5 2 2.5 3

     Load (kW)

     Diesel BD BD60 BD70 BD80 BD90 BD100

3. Conclusion :

Fig.14 NO Vs Load with various temperatures of JME.

1. Better net heat release rate computed from combustion pressure values.

2. Jacked up cumulative heat release rate curve throughout

The performance emission and combustion were evaluated. Biodiesel heated at 600C is the efficient one in view of the engine performance, combustion performance and the emission aspects described in the results. The benefits are as follows.

1. Smooth combustion pressurerise despite delayed peak pressure.

indicating better premixed and diffused combustion.

1. Smoother thermal efficiency rise and better performance at the highest load.

   Economical BSFC when compared to unheated biodiesel.

2. Lower exhaust gas temperatures at higher part loads indicating better torque conversion.

3. Average smoke level lesser than the unheated

   biodiesel in general.

4. Reduced CO, HC levels in exhaust.

5. Parity with the unheated biodiesel at all loads the emission context of NO.

Hence it can be concluded that the biodiesel heated to 600 C electronically before injection into the cylinder, entails better fuel injection, air entrainment, conservative heat transfer and better combustion in the main chamber with economical torque conversion.

REFERENCES:

1. World Resource Institute. World GHG emissions flow chart; 2010.

2. Pramanik, K., Properties and Use of Jatropha Curcas Oil and Diesel Fuel Blends in Compression ignition Engine, Renewable Energy, 28 (2003), 2, pp. 239-248.

3. Agarwal, D. A., Agarwal, A. K., Performance and Emission Characteristics of Jatropha Oil (Pre heated and Blends) in a Direct Injection Compression Ignition Engine, Applied Thermal Engineering, 27 (2007), pp.2314-2323

4. Varaprasad, C.M. Murali Krishna, M.V.S.Prabhakar Reddy. C., Investigations on Biodiesel (Esterified JatrophaCurcas Oil) in Diesel Engines, XV National Conference on IC Engines and Combustion, Anna University, Chennai, India, 1997

[5]. Mcdonald JF, Purcell DL, McClure BT, Kittelson DB.Emission characteristics of Soy methyl ester fuels in an IDI compression ignition engine. SAE paper no. 950400, 1995.

[6]. Kumar Senthil M, Ramesh A, Nagalingam B. An experimental comparison of methods to use methanol and Jatropha oil in a compression ignition engine. Biomass Bioenergy; 25:30918. 2003.

[7]. Selim MYE, Radwan MS, Elfeky SMS.Combustion of jojoba methyl ester in an indirect injection diesel engine. Renew Energy; 28:140120. 2003.

1. Vander Walt AN, Hugo FJC. Attempts to prevent injector cooking with sunflower oil by engine modifications and fuel additives. Vegetable Oil Fuels Proceedings of the International Conference on Plant and Vegetable Oils as Fuels 1982; 4(82):22330.

2. Hawkins CS, Fuels J, Hugo FJC. Engine durability tests with sunflower oil in an indirect injection diesel engine. SAE Paper; 1983.No. 831357.

3. Karaosmanoglu F, Kurt G, O¨ zaktasx T. Long term CI engine test of sunflower oil. Renewable Energy 2000; 19(12):21921.

4. Karaosmanoglu F, Kurt G, O¨ zaktasx T. Direct use of sunflower oil as a compression-ignition engine fuel. Energy Sources 2000; 22(7):65972.

5. O¨zaktasx T. Compression ignition engine fuel properties of a used sunflower oildiesel fuel blend. Energy Sources 2000; 22(4):37782.

6. Senthil Kumar M, Kerihuel A, Bellettre J, Tazerout M. Experimental investigations on the use of preheated animal fat as fuel in a compression ignition engine. Renewable

   Energy 2005; 30(9):144356.

7. Agarwal D, Agarwal AK. Performance and emissions characteristics of Jatropha oil (preheated and blends) in a direct injection compression ignition engine. Applied Thermal Engineering 2007; 27(13):231423.

8. Kalam MA, Masjuki HH. Emissions and deposit characteristics of a small diesel engine when operated on preheated crude palm oil. Biomass and Bioenergy 2004; 27(3):28997.

9. Pugazhvadiu M, Jeyachandran K. Investigations on the performance and exhaust emissions of a diesel engine using preheated waste frying oil as fuel. Renewable Energy 2005; 30(14):2189202.

10. Cetinkaya S. The potential of using sunflower oil as a fuel for diesel engines. Journal of Thermal Science and Technology 1995; 17(4):21 32.