riw

h i g h l i g h t s

A novel lubricity additive was used for Hydrox thansel in tCI eng

ion in particulate matter (PM), carbon monoxide (CO) and hydrocarbon (HC)

crude oil scenario has been registering a paradigm shift from fossilto shale oil (tight oil) in the recent past. But shale oil, a low costresource is not renewable in nature and makes other alternatives(carbon neutral transport fuels) less attractive, so adversely

ous concerns overtill a majoen economction of al

of petroleum products [3]. Complying with stringent emnorms for the latest automotive engines poses another chto the automotive industry. In the wake of these challenges, biofu-els, being renewable in nature and offering the hope of some mea-sure of self-reliance, has been emphasised during the last decade asone of the viable alternatives for compression ignition (CI) engines.The Government of India launched the National Mission onBiodiesel in April 2003 under the National Policy on Biofuel, declar-ing Jatrophacurcas as the most suitable tree-borne oilseed for

Corresponding author at: Indian Institute of Petroleum, Mohkampur, HaridwarRoad, Dehradun 248005, India. Tel.: +91 135 2525874.

E-mail addresses: devendra@iip.res.in (D. Singh), subra@ces.iitd.ac.in(K.A. Subramanian), satish@iip.res.in (S.K. Singal).

Applied Energy 155 (2015) 440446

Contents lists availab

Applied

lseEnergy is considered as the backbone of any growing economy.The latest world energy outlook report states that China will dom-inate energy demand growth until mid-2020s. After that India willtake over as the leading engine of energy demand [1]. The global

recent slowdown in oil production may raise serithe oil supply [1]. Therefore, energy security is slenge for Indian economy. India is a diesel drivPetro-diesel accounted for 42.47% of total produhttp://dx.doi.org/10.1016/j.apenergy.2015.06.0200306-2619/ 2015 Elsevier Ltd. All rights reserved.r chal-y andl typesission

allengeHydroprocessed Renewable Diesel (HRD)European Stationary Cycle (ESC)Regulated emissions

emissions as compared to petro-diesel. But NOx increased by 26% for HRD and 77% in the case of B100fueled engine. Brake specic fuel consumption (BSFC) of the engine fueled with HRD was lower than withB100 and petro-diesel. A comparative analysis of emission results revealed that the engine fueled withB100 performed well on many counts such as PM, CO and HC, but the HRD outperformed B100 in termsof NOx emission and BSFC, which are vital parameters for CI engines. Hence, HRD may be considered as apromising alternative fuel for CI engines over other transesteried biodiesels.

2015 Elsevier Ltd. All rights reserved.

1. Introduction affecting our environment [2]. India imports most of the crudeoil for its energy requirement from Middle East countries and theKeywords:Jatrophacurcas biodiesel (B100)

showed substantial reduct HRD fueled engine emits 29% lower NO HRD outperformed B100 and petro-die HRD is a promising alternative fuel for

a r t i c l e i n f o

Article history:Received 30 January 2015Received in revised form 10 June 2015Accepted 14 June 2015processed Renewable Diesel (HRD).B100 fuel.erms of BSFC.ine.

a b s t r a c t

Renewable biofuels such as Hydroprocessed Renewable Diesel (HRD) and Biodiesel (B100) are perceivedas potential alternative fuels for compression ignition (CI) engine. HRD and B100 are produced from thesame feedstock i.e. Jatrophacurcas oil by transesterication and hydro-deoxygenation reactions respec-tively. Petro-diesel served as a reference fuel. The main objective of this study is to identify a better alter-native fuel among HRD and B100 in terms of emissions and fuel consumption characteristics. The CHObased lubricity additive was added in HRD to give adequate lubricity to fuel injection pump. Both biofuelsa Indian Institute of Petroleum, Mohkampur, Haridwar Road, Dehradun 248005, IndiabCentre for Energy Studies, Indian Institute of Technology, Hauz Khas, Delhi 110016, IndiaEmissions and fuel consumption characteengine fueled with Hydroprocessed Rene

Devendra Singh a,b,, K.A. Subramanian b, S.K. Singal a

journal homepage: www.estics of a heavy duty dieselable Diesel and Biodiesel

le at ScienceDirect

Energy

vier .com/ locate/apenergy

Previous research work on the application of biofuels in CI engi-nes was emphasized through the comparative performance andemissions of these biofuels against petro-diesel. Knothe et al.[32] reported that hexadecane and dodecane (alkane componentsof petro-diesel) reduces NOx on the Federal Test Procedure (FTP)cycle compared to petro-diesel, due to the absence of unsaturationin these alkanes which negates the effect of chain length on NOx.Another recent study by Na et al. [30] showed a reduction ofNOx in urban dynamometer driving schedule (UDDS) for renew-able diesel as compared to petro-diesel, but highway cruise didnot show any signicant change in NOx with the usage of HRD inheavy duty trucks but, these tests were conducted on a chassis

properties, emissions and performance. Knothe et al. [32] used a

nergy 155 (2015) 440446 441biodiesel production in India [4]. The Bureau of Indian Standards(BIS) has already prepared a standard (IS-15607) for B100 biodie-sel, which is the Indian adaptation of ASTM D-6751 andEN-14214 [5].

Second generation biodiesel fuels produced from differentsources were extensively studied as neat as well as a blended fuelin a CI engine with respect to typical fuel properties, engine perfor-mance and engine exhaust emissions. It is reported in most of theliterature that, NOx increases with the use of biodiesel due tohigher adiabatic ame temperatures and oxygen contents [610].A few researchers found the opposite trend [11,12], negating theidea that biodiesel fuel bound oxygen increases NOx emissions.An et al. [13] showed a reduction of NOx with the use of B100,owing to lower in-cylinder pressure and heat release rate, exceptunder a few operating conditions (low speeds and high load),where the opposite trend was observed. However, it has emergedfrom the literature, and agreed by the majority of researchers, thatfundamental effects such as higher levels of unsaturation (iodinenumber) in biodiesel would increase the adiabatic ame tempera-ture and consequently thermal NOx emissions. Sun et al. [14]reported that diesel engines equipped with the pump line nozzle(PLN) type of fuel injection, which prevents effects such as theinadvertent advance of the start of injection due to the higher bulkmodulus and viscosity of biodiesel, lead to an increase in combus-tion temperature and hence thermal NOx. This effect wasdescribed by Caresana [15] and contradicted the common beliefthat biodiesel always entails higher injection pressures.

Poor oxidative stability and the poor cold ow properties of bio-diesel were considered major stumbling blocks behind its utiliza-tion in a CI engine as a neat fuel. Hence, nding an alternativerenewable fuel which not only addresses the environmental issues,but also possesses better oxidative stability and low temperaturecharacteristics, is the need of the hour. HydroprocessedRenewable Diesel (HRD) has been identied as a prospectivealternative fuel for CI engine application in the recent past. HRDis also known by terms such as hydrotreated vegetable oil (HVO),hydrogenated vegetable oil (HVO), renewable diesel, green diesel,Bio-Hydrogenated Diesel (BHD), and hydrogenation derivedrenewable diesel (HDRD) [16]. It possesses similar physico-chemical properties as that of petro-diesel and can be producedfrom any triglyceride oil, utilising the existing infrastructure ofconventional petroleum processing facilities [17]. It was also esti-mated that lifetime emissions from green diesel (HRD) were lowerthan that of biodiesel and petroleum diesel [18].

HRD possesses a very high cetane number (CN) and better coldow properties, oxidative stability and caloric value than biodie-sel. The bulk modulus of HRD is lower than those of biodiesel andpetro-diesel at higher injection pressures [19]. Sugiyama et al. [20]reported that brake thermal efciency of an engine fueled withHVO is higher than petro-diesel. Mass based fuel consumption ofneat HRD or blends with petro-diesel are also reported to be lowerthan petro-diesel, due to its relatively higher heating value[21,22,2427].

Emission characteristics of neat HRD have been studied exten-sively. Most literature shows signicant reduction in CO, HC, PMand smoke emissions with the use of the HRD againstpetro-diesel but the reported results on NOx emissions areambiguous. A majority of researchers [16,22,23,25,2729] showedthat HRD reduces NOx, whereas some are uncertain about NOxemission and tried to correlate it with driving conditions[20,30,31], and a few have reported that NOx increases with theuse of HRD [24,26] due to its higher CN and heating value. It wasshown that HRD leads to higher in-cylinder pressure and heat

D. Singh et al. / Applied Erelease rate as compared to diesel, which results in slightly higherNOx. Overall, it is still unclear whether HRD reduces or increasesNOx emissions in comparison to petro-diesel.commercial lubricity additive for renewable diesels whereas anovel lubricity additive (sulphur less) was used in this study.Engine test were conducted on engine dynamometer usingEuropean Stationary Cycle (ESC) to investigate the effect of fuelproperties and engine operating conditions on raw emissions andperformance under controlled test cell condition, i.e. fuel tempera-tures, intake air pressure and relative humidity were kept the samefor all tests. ESC is one of the mandatory legislative cycle used forcertication of heavy duty engine emissions (Euro III and beyond).Since HRD is proposed to be used in an unmodied diesel enginesas a drop-in fuel to supplement diesel in the near future. Its perfor-mance and emission characteristics on this cycle are worthstudying.

2. Materials and methodology

2.1. Production of Hydroprocessed Renewable Diesel and Biodiesel

HRD and biodiesel samples were produced from Jatrophacurcasoil, using the process described by Kumar et al. [34] and Ghoshet al. [35] respectively. Typical fuel properties of petro-diesel,HRD and B100 are shown in Table 1. It is important to note that833 ppm of the synthesised lubricity additive (CHO) was addedin HRD fuel to match the desired fuel properties specied in ASTMD975 and provide adequate lubricity to fuel injection system.

Table 1Pysico-chemical Properties of Petro-diesel, HRD, B100.

Fuel properties Petro-diesel HRD B100

Density at 15 C kg/m3 831 804 870Viscosity at 40 C mm2/s 3.18 3.43 4.6Flash point, min C 65 122.7 171Net caloric valuea MJ/kg 42.26 43 37.7Cetane number (CN) min 51 >74 59.4Oxygen nil 87 ppm 12%Water content ppm 59 46 410Sulphur ppm 481 nil nil

a Net caloric values were calculated using the formula: NCV = GCV Heat ofdynamometer and the vehicle exhaust was diluted with air andpassed through constant volume sampling (CVS) before emissionmeasurements. Moreover, speeds and torques of a chassisdynamometer cannot be compared with an engine dynamometertest. Westphal et al. [33] compared the emissions of a heavy dutydiesel engine fueled with hydrotreated vegetable oil (HVO,Trademark: NExBTL) and Jatropha methyl ester (JME). It wasreported that the engine fueled with HVO produced lower NOxthan diesel and JME, but no justication was provided for thistrend. Whereas, in the present study, two biofuels (HRD andB100) produced from same feedstock (Jatrophacurcas oil) have beencompared against Petro-diesel, with respect to physic-chemicalevaporation of water generated due to combustion of the fuel, where GCV and NCVcorrespond to Gross caloric value and Net caloric value, respectively; GCV wasestimated following the procedure of ASTM D 4809.

2.2. Test engine and engine dynamometer

Experiments were conducted on a four stroke, six-cylinder,direct injection, water-cooled, heavy duty diesel engine coupledwith a transient dynamometer of 440 kW, capable of running theEuropean Stationary Cycle (ESC). A brief specication of the testengine is given in Table 2 and the schematic of the engine test

Engine torques, speeds, emissions and fuel consumption data

chamber was used, whose temperature was maintained at

NOx, prompt NOx and fuel bound NOx. The thermal NOx is a post

442 D. Singh et al. / Applied Energ295 3 K (22 3 C) and a relative humidity at 45 8%.

Table 2Engine Specications.

Engine type 6-cylinder, Euro-III/Bharat Stage-III, DI,Turbocharged, water-cooled, diesel engine

Displacement 5.9 ccFiring order 1-5-3-6-2-4Maximum horse power 180 hp @ 2500 rpmwere logged continuously throughout the test cycle at the rate of10 Hz. Specic emissions and brake specic fuel consumption val-ues for each mode were also computed. The measured data werecollected under identically controlled conditions for all fuels. Thetest cell temperature was maintained in the range of 2330 C,while the engine inlet air temperature and relative humidity werecontrolled at 25 1 C and 3540% respectively.

Measurement of PMwas done by extracting a raw exhaust sam-ple from the engine exhaust stream and mixing it with dilution airusing a partial ow dilution ratio in such a way that the tempera-ture at the test lter remained below 325 K (52 C). PM sampleswere taken on 70 mm Teon coated glass ber lters (PallexT60A). For gravimetric analysis of PM, a conditioned weighing3.1. Test cycle

European Stationary Cycle (ESC), a thirteen mode steady statecycle with different weighting factor, was used for measuring fuelconsumption and emission characteristics. ESC is a combination ofthree speeds and four load points; duration of each mode is 120 s,except the rst mode (idle) whose duration is 240 s. The total dura-tion of ESC is around 1680 s. Calculated values of A, B, C speeds are1609 rpm, 1907 rpm and 2205 rpm respectively. Details of the ESCmodes along with weighting factors are shown in Fig. 2.

3.2. Methodologybench setup is shown in Fig. 1.

2.3. Fuel ow meter and emission analysers

Fuel consumption measurements were performed for all fueltypes using fuel ow meter (AVL 735) based on coriolis principleand fuel temperature were maintained at 38 C. Engine exhaustemissions (CO, HC, NOx and PM) were measured using an instanta-neous raw gas emission analyser (AVL AMAi60), employing achemi-luminescence detector (CLD) for NOx measurements,heated ame ionization detection (HFID) for total hydrocarbonsand non-dispersive infrared detection (NDIR) for CO. The particu-late matter (PM) for all fuel types was measured using the partialow dilution tunnel (AVL SPC 472). Measuring range and accuracyof the different devices used in this study are given in Table 3.

3. Test cycle and methodologyPeak torque, Nm 675Nm@1500 rpmFuel system Distributor injection pumpame phenomenon, strongly dependent on in-cylinder combustiontemperature that can be analysed by the extended Zeldovichmechanism [36]. Prompt NOx is formed by reaction of atmosphericnitrogen with hydrocarbon radicals during rich combustion,whereas fuel bound NOx formed by reaction of fuel-bound nitro-gen with the oxygen. However, thermal NOx is considered as themain contributor to NOx formation in a CI engines at higher com-bustion temperatures. Dec [37] also proposed a conceptual modelof NOx formation, reporting that the bulk of NOx formationoccurred on the lean side of the diffusion ame during thequasi-steady-state combustion period and in the bulk gases afterthe primary heat release ends.

Specic NOx (g/kW h) of the engine fueled with Petro-diesel,HRD and B100 was calculated by using the following formula;

Specific NOx Pi13

i1 MassNOxi WFiPi13i1 Poweri WFi

where MassNOx = qNOx CNOx qexhqNOx = ratio of density of exhaust component and density of

exhaust gasCNOx = concentration of the respective component in the raw

exhaust gas, ppmqexh = exhaust mass ow rate, kg/hWFi = weighting factorPoweri = engine power in each mode, kWSpecic NOx values for all fuels are shown in Table 4. B100 andEngine benchmarking in terms of fuel consumption and emis-sions measurement was done on Petro-diesel, followed by HRDand nally B100. ESC test was repeated three times for each fuelto estimate the uncertainty (systematic and random) of measuredvalues and the results were reported at 95% condence level.Utmost care was taken to avoid any intermixing of fuel samples,by using a fresh fuel lter for each fuel type, and purging the fuelow lines of an engine as well as the fuel ow-meter and fuel con-ditioning system each time during changeover.

3.3. Error analysis

Experimental uncertainty analyses for all measured values aswell as derived values were reported at 95% condence level. Theoverall estimation of uncertainty of a measured value x wasobtained in terms of root-of-the-sum-of-the-squares (RSS)accounted for each of the component elements of the uncertaintiesi.e.

ux XiK

i1u2i

r

The overall uncertainty for all derived values was calculatedusing the principal of propagation of uncertainty, including bothbias (systematic) and precision (random) uncertainties;

ux usystematic2 urandom2

q

4. Results and discussions

4.1. Mass emissions results

4.1.1. Specic NOx emissionsNitrogen oxides (NOx) formations in an internal combustion

engine can be explained by three mechanisms such as thermal

y 155 (2015) 440446HRD fueled engine showed 77% and 26% higher NOx respectivelythan petro-diesel. Among HRD and B100 fuels, it is interesting tonote that the HRD fueled engine showed 29% lower NOx than B100.

nergD. Singh et al. / Applied EIt is observed from Table 4 that B100 produced higher NOx thanHRD and petro-diesel. This trend may be explained by the higherdegree of hydrocarbon unsaturation (Iodine number 93.78) andpresence of around 12% oxygen, which are known to have a syner-gistic effect on NOx emissions and are directly correlated withthermal NOx. The effect of higher levels of unsaturation in thehydrocarbon chain on NOx emissions was also reported byMcCormick et al. and Schonborn et al. [38,39]. System effects suchas the articial advance of the start of injection for B100 fuel mayalso result in higher NOx. On the other hand HRD (predominantly asaturated hydrocarbon fuel with negligible amount of oxygen andhaving lower bulk modulus than B100) showed relatively lowerNOx than B100.

The HRD fueled engine shows higher NOx than Petro-diesel.HRD, (higher CN than petro-diesel) when injected in the engineat its default injection timing, results in relatively shorter ignitiondelay, thereby advancing the start of combustion (SOC) in thecycle, which ultimately raises the pressure and local gas tempera-ture in the cylinder, thus leading to higher thermal NOx formation.

Fig. 1. Schematic of engine d

Table 3Measuring range and accuracy.

Emission analysers Measuring range Accuracy

CLD for NOxLowest possible measuring range 010 ppm 60.3% of lowest

range full scaleHighest possible measuring range 010,000 ppmFID for HCLowest possible measuring range 010 ppm C3 60.3% of lowest

range full scaleHighest possible measuring range 020,000 ppmNDIR for COLowest possible measuring range 050 ppm 60.3% of lowest

range full scaleHighest possible measuring range 05000 ppmParticulate matter microbalance 02.1 g 0.001 mgFuel ow meter 0125 kg/h 0.12%y 155 (2015) 440446 443Similar trends of higher NOx for HRD were also reported byKousoulidou et al. [26]. Hence, higher CN fuels injected at theengines default injection timing would produce more NOx. ButNOx emitted from the engine fueled with HRD was signicantlylower than for B100, although it has a very high CN. The reasonfor this reduction could be attributed to the lower bulk modulus[19] and negligible oxygen content of HRD that probably counter-balanced the effect of higher CN to some extent, thus limiting NOxemissions quite lower than the B100. Higher NOx may, however,be further reduced for the HRD fueled engine by using the exhaustgas recirculation (EGR) or by retarding the fuel injection timing ofthe engine or by using selective catalytic reduction (SCR) devices inthe exhaust stream. It may be inferred from these results that HRDoutperformed B100 in terms of NOx emission reduction, which isconsidered as an important pollutant so far as biofuels in CI engi-nes is concerned.

ynamometer test bench.

Fig. 2. ESC description mode wise along with weighting factor (%).

4.1.2. Mode-wise NOx emissionAveraged NOx emissions (mode-wise) for Petro-diesel, HRD and

B100 fuels after completion of ESC are shown in Fig. 3. It isobserved that NOx emission was highest for B100 and lowest inthe case of petro-diesel, whereas the HRD fueled engine producedhigher NOx than Petro-diesel but consistently lower than B100 fuelduring all 13 modes.

Table 5Comparative specic PM emission (g/kW h).

Fuel type PM (g/kW h) Uncertainty

Petro-diesel 0.077 0.015HRD 0.056 0.003

Table 4Comparative specic NOx emission (g/kW h).

Fuels Specic NOx Uncertainty

Diesel 5.26 0.28HRD 6.64 0.11B100 9.31 0.15

444 D. Singh et al. / Applied Energy 155 (2015) 440446Further investigations done on three modes i.e. second, eighthand tenth modes, where speeds were 1609, 1907 and 2205 rpmrespectively, and loads were 100%, revealed that NOx emissionwas lowest in the tenth mode, highest in the second mode and liesin between in the eighth mode. Higher NOx in the second mode(lower speed) may be correlated with the longer residence timeavailable for combustion products, in contrast to the other twomodes where residence time was relatively short. On the otherhand, NOx analysis during the 10th to 13th modes (engine speed2205 rpm and varying torque) revealed that NOx emission wasdirectly proportional to engine load (torque). This is strongevidence that both speed and load inuence NOx emissions signif-icantly. Moreover, the magnitude of NOx at full load is predomi-nantly depends on the engine speed. For example, the heavyduty engine emits more NOx during uphill driving conditions(low speed and full load).

4.1.3. Particulate matter (PM) emissionsTable 5 shows the brake specic PM emissions of the engine

fueled with petro-diesel, HRD and B100 running on ESC. It isobserved that PM fell by around 27% and 43% with the use ofHRD and B100 fuels respectively in place of petro-diesel, indicatingthe merits of these biofuels in terms of PM emissions. Soot forma-tion during combustion is a complex phenomenon and depends onmany parameters such as fuel/air ratio, ignition delay, and fuelcomposition (aromatic and sulphur content). The observed declinein the PM with the use of HRD may be correlated with the negligi-ble sulphur and aromatic content of HRD. Moreover, higher CN ofHRD may cause shorter ignition delay resulting in less soot forma-tion during premixed phase, which further aids PM reduction.Reduction in PM with the use of B100 is also expected, as its oxy-gen content might be expected to aid efcient combustion.

1000

1200

1400

pm

Petro-diesel

HRD

B1000

200

400

600

800

1 2 3 4 5 6 7 8 9 10 11 12 13

NO

x, p

Modes

Fig. 3. Comparative NOx emission (ppm) during ESC.Moreover, biodiesel also had negligible sulphur that augmentsthe additional reduction in PM. The HRD fueled engine producedonly 27% more PM than B100. This higher PM level for HRD maybe correlated with the negligible oxygen content of this fuel.Although PM emissions were higher for HRD than for B100, theabsolute gure was only 0.056 g/kW h, which was still around44% less than the ESC specied limit of 0.1 g/kW h for the EuroIII diesel engine.

4.1.4. CO and HC emissionsAveraged values of brake specic CO and HC emissions from

engines fueled with petro-diesel, HRD and B100 after completionof ESC are shown in Table 6. The data shows the advantage ofthe biofuels (HRD and B100) over petro-diesel in terms of CO andHC emissions. In general, formation of CO in a CI engine is attribu-ted to incomplete combustion processes and HC emissions dependon the quality of the fuel and air mixture. From Table 6 it can beseen that HRD and B100 reduce CO emission by 16% and 27%,and HC emission by 16% and 41% respectively compared withpetro-diesel. This reduction in CO and HC for B100 was expected,as it contains around 12% oxygen. The HRD fuel showed a signi-cant reduction in CO and a marginal reduction in HC, probablybecause of better combustion characteristics linked to its higherCN than petro-diesel. Among the two biofuels, HRD showed mar-ginally higher CO and HC emissions compared to B100, unsurpris-ing given its absence of oxygen content. However, the absolutevalues of CO and HC emissions, even in the case of HRD, were muchlower than the ESC specied limits of 2.1 g/kW h and 0.66 g/kW h,respectively, for the Euro III diesel engine.

4.1.5. Mode-wise CO and HC emissionsFig. 4 illustrates the concentration of CO in ppm in the exhaust

gases during the ESC for petro-diesel, HRD and B100. It is observedthat, similar trend are seen in all modes, with the highest CO forpetro-diesel, lowest for B100 and for HRD, it is relatively higherthan B100 but consistently lower than petro-diesel. B100 showedthe different trend in the rst mode (idle speed 750 rpm and zeroload) and in the seventh mode (lower speed 1609 rpm and only25% load). Higher CO was observed for B100 than for HRD, thatmay be attributed to the higher viscosity of B100, which may resultin poor atomization and only partial burning of B100 at the lowerin-cylinder temperatures in these modes. It is noteworthy to statethat in modes 2, 8 and 10 (full load at varying speeds) almost iden-tical CO concentrations were seen, indicating the insensitivity ofCO emission towards speed at full load. The effect of engine loadon CO may be observed from results in modes 10 to 13, where

B100 0.044 0.001the speed was 2205 rpm and load was varied from 100% to 25%,CO was lowest in 10th mode (100% load) and highest in 11th mode(25% load) among these four modes. Hence, it may be inferred from

Table 6Specic CO and HC after completion of ESC.

Fuel type CO, g/kW h Uncertainty HC, g/kW h Uncertainty

Petro-diesel 0.50 0.02 0.060 0.020HRD 0.42 0.05 0.050 0.012B100 0.37 0.01 0.035 0.010

BSFC, whereas B100 registered the highest BSFC. This trend was

nerg20

40

60

80

100

120

140

CO, p

pm

Petro-diesel

HRD

B100

D. Singh et al. / Applied EFig. 4 that CO emissions are inversely related to engine load andshow little sensitivity towards speed under full load operations.

Comparative steady state HC emissions for petro-diesel, HRDand B100 in each mode are shown in Fig. 5. It is observed that dur-ing the rst mode (750 rpm and no load) and seventh mode(1609 rpm and 25% load) HC emissions are relatively higher thanfor the rest of the modes. This suggests that HC emissions areinversely related to engine load, possibly due to owing to overlean-ing of the air/fuel mixture during these mild operating conditions.

4.2. Fuel consumption

Fuel consumption of the engine fueled with all three fuels(petro-diesel, HRD and B100) was measured during the ESC. Its

els Hydroprocessed Renewable Diesel (HRD) and Biodiesel (B100),

the main source of inspiration behind this experimental study.Thanks are also due to Dr A.K. Sinha and Hydro-processing group

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12 13

HC, p

pm

Modes

Petro-diesel

HRD

B100

Fig. 5. Comparative HC emission (ppm) during ESC.

180

200

220

240

260

280

300

320

340

2 3 4 5 6 7 8 9 10 11 12 13

BSFC

,g/k

Wh

Modes

Petro-diesel

HRD

B100

Fig. 6. Brake Specic Fuel Consumption (g/kW h) during ESC.

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Modes

Fig. 4. Comparative CO emission (ppm) during ESC.for providing the Hydroprocessed Jatrophacurcas oil and Dr. A KChatterjee for synthesising and providing the lubricity additive.Acknowledge Mr. Kalyan Singh and Mr Satish Kumar for evaluatingCetane number and caloric value of fuels respectively. Last butnot the least; authors bestow their gratitude to all staff membersof AFLAD lab.

Referencesproduced from the same source, i.e. Jatrophacurcas oil, on regulatedemissions and fuel consumption of a CI engine, compared topetro-diesel. A CHO based lubricity additive was added intoHRD to meet the fuel properties as specied in ASTM D975 andto provide adequate lubricity to fuel injection systems.Comparative emission and fuel consumption characteristics ofthe engine were studied to identify the better biofuel of the two:HRD and B100. Following points may be concluded from this study.

HRD fuel exhibits physico-chemical properties specied inASTM D 975.

The use of neat biofuels (HRD and B100) results in signicantreductions in PM, HC and CO emissions compared topetro-diesel, but NOx is substantially higher.

The HRD fueled engine produced around 29% lower NOx emis-sions than B100.

The HRD fueled engine showed 27% higher PM emission thanB100, but the absolute value was only 0.056 g/kW h, whichwas still around 44% less than the ESC specied limit of0.1 g/kW h

For all fuels (petro-diesel, B100 and HRD) NOx emissions weredirectly related to engine load, but inversely related to speed,whereas CO and HC emissions were inversely related to engineload.

The fuel consumption, expressed as the BSFC, for the enginefueled with HRD, was lower than for B100 and petro-diesel.

HRD outperformed B100 in terms of the NOx emissions and fueleconomy, which are vital parameters if they are to be used asbiofuels in CI engines.

The overall conclusion is that HRD fuel in particular is a promis-ing biofuel, which has potential to substitute other transesteri-ed biodiesels.

Acknowledgement

The authors extend sincere thanks to the Director, IIP for beingattributed to a higher caloric value of HRD (around 14%) thanB100. HRD also showed a lower BSFC than Petro-diesel, which isa very important nding in terms of fuel conservation and a signif-icant advantage associated with the HRD. This reduction may beexplained by the marginally higher caloric value of HRD (around2%) than petro-diesel (Table 1).

5. Conclusions

The experimental study investigated the effect of the two biofu-brake specic values (g/kW h) are shown in Fig. 6. It is interestingto note that HRD fueled engine consistently showed the lowest

y 155 (2015) 440446 445[1] International Energy Agency (IEA). World Energy Outlook 2014 (WEO-2014).12 November 2014.

[2] Shale oil: the next energy revolution. February 2013. .

[3] Energy Statistics 2015. Government of India. Ministry of Statistics andProgramme Implementation. Central Statistics Ofce New Delhi, 2015..

[4] Basavaraj G, Parthasarathy PR, Reddy RC, Kumar AA, Rao PS, Reddy BVS. Areview of the national biofuel policy in india: a critique of the need to promotealternative feedstocks. International Crops Research Institute for the Semi-AridTropics, 2012.

[5] Bureau of Indian Standard. IS:15607.[6] Lahane S, Subramanian KA. Effect of different percentages of biodieseldiesel

blends on injection, spray, combustion, performance, and emissioncharacteristics of a diesel engine. Fuel 2015;139:53745.

[7] Bari S. Performance, combustion and emission tests of a metro-bus running onbiodiesel-ULSD blended (B20) fuel. Appl Energy 2014;124:3543.

[8] Chattopadhyay S, Sen R. Fuel properties, engine performance andenvironmental benets of biodiesel produced by a green process. ApplEnergy 2013;105:31926.

[9] Tan P, Hu Z, Lou D, Li Z. Exhaust emissions from a light-duty diesel engine withJatropha biodiesel fuel. Energy 2012;39:35662.

[10] Ganapathy T, Gakkhar RP, Murugesan K. Inuence of injection timing onperformance, combustion and emission characteristics of Jatropha biodieselengine. Appl Energy 2011;88:437686.

[11] Lapuerta M, Armas O, Ballesteros R, Fernandez J. Diesel emissions frombiofuels derived from Spanish potential vegetable oils. Fuel 2005;84:77380.

[12] Ng J, Ng H, Gan S. Characterisation of engine-out responses from a light dutydiesel engine fueled with palm methyl ester. Appl Energy 2012;90:5867.

[13] An H, Yang WM, Maghbouli A, Li J, Chou SK, Chua KJ. Performance, combustionand emission characteristics of biodiesel derived from waste cooking oils. ApplEnergy 2013;112:4939.

[14] Sun J, Carton JA, Jacobs TJ. Oxides of nitrogen emissions from biodiesel-fuelleddiesel engines. Prog Energy Combust Sci 2010;36:67795.

[23] Jaroonjitsathian S, Tipdecho C, Sukajit P, Namthirach N, Suppatvech S. Bio-Hydrogenated Diesel (BHD): Renewable Fuel for Advanced Diesel Technology.SAE Tech Pap 2013-01-0070. http://dx.doi.org/10.4271/2013-01-0070.

[24] Murtonen T, Aakko-Saksa P, KuronenM,Mikkonen S and Lehtoranta K. Emissionswith Heavy-duty Diesel Engines and Vehicles using FAME, HVO and GTL Fuelswith and without DOC+POC Aftertreatment. SAE 200901-2693, SAE Int J FuelsLubr, vol. 2, 2009. p. 14766. http://dx.doi.org/10.4271/2009-01-2693.

[25] Gowdagiri S, Cesari XM, Huang M, Oehlschlaeger MA. A diesel engine study ofconventional and alternative diesel and jet fuels: ignition and emissionscharacteristics. Fuel 2014;136:25360.

[26] Kousoulidou M, Dimaratos A, Karvountzis KA, Samaras Z. Combustion andemissions of a common-rail diesel engine fueled with HWCO. J Energy Eng2014;140. A4013001(9).

[27] Ogunkoya D, Roberts WL, Fang T, Thapaliya N. Investigation of the effects ofrenewable diesel fuels on engine performance, combustion, and emissions.Fuel 2015;140:54154.

[28] Erkkila K, Nylund NO, Hulkkone T, Tilli A, Mikkonen S, Saikkonen P, et al.Emission performance of parafnic HVO diesel fuel in heavy duty vehicles. SAETech Pap 2011-01-1966; 2011. http://dx.doi.org/10.4271/2011-01-1966.

[29] Khan MY, Russell RL, WelchWA, Cocker III DR, Ghosh S. Impact of algae biofuelon in-use gaseous and particulate emissions from a marine vessel. EnergyFuels 2012;26:613743.

[30] Na K, Biswas S, Robertson W, Sahay K, Okamoto R, Mitchell A, et al. Impact ofbiodiesel and renewable diesel on emissions of regulated pollutants andgreenhouse gases on a 2000 heavy duty diesel truck. Atmos Environ2015;107:30714.

[31] Paum H, Hofmann P, Geringer B, Weissel W. Potential of hydrogenatedvegetable oil (HVO) in a modern diesel engine. SAE paper 201032-0081, 2010.http://dx.doi.org/10.4271/2010-32-0081.

446 D. Singh et al. / Applied Energy 155 (2015) 440446[15] Caresana F. Impact of biodiesel bulk modulus on injection pressure andinjection timing the effect of residual pressure. Fuel 2011;90:47785.

[16] No SY. Application of hydrotreated vegetable oil from triglyceride basedbiomass to CI engine a review. Fuel 2014;115:8896.

[17] Knothe G. Biodiesel and renewable diesel: a comparison. Prog Energy CombustSci 2010;36:36473.

[18] R. D. S. of the WSDA Technical Work Group. Renewable Diesel Technology,2007. .

[19] Lapuerta M, Agudelo JR, Prorok M, Boehman AL. Bulk modulus ofcompressibility of diesel/biodiesel/HVO blends. Energy Fuels 2012;26:133643.

[20] Sugiyama K, Goto I, Kitano K, Mogi K, Honkanen M. Effects of HydrotreatedVegetable Oil (HVO) as renewable diesel fuel on combustion and exhaustemissions in diesel engine. SAE Int J Fuels Lubr 2012;5:20517. http://dx.doi.org/10.4271/2011-01-1954.

[21] Kim D, Kim S, Oh S, No SY. Engine performance and emission characteristics ofhydrotreated vegetable oil in light duty diesel engines. Fuel 2014;125:3643.

[22] Aatola H, Larmi M, Sarjoyaara T, Mikkonen S. Hydrotreated Vegetable Oil(HVO) as a renewable diesel fuel: trade-off between NOx, particulate emission,and fuel consumption of a heavy duty engine. SAE Int J Engines2009;1:125162. http://dx.doi.org/10.4271/2008-01-2500.[32] Knothe G, Sharp CA, Ryan III TW. Exhaust emissions of biodiesel, petrodiesel,neat methyl esters, and alkanes in a new technology engine. Energy Fuels2006;20:4038.

[33] Westphal GA, Krahl J, Munack A, Rosenkranz N, Schrder O, Schaak J, et al.Combustion of hydrotreated vegetable oil and jatropha methyl ester in a heavyduty engine: emissions and bacterial mutagenicity. Environ Sci Technol2013;47:603846.

[34] Kumar R, Rana BS, Tiwari R, Verma D, Kumar R, Joshi RK, et al. Hydroprocessingof jatropha oil and its mixtures with gas oil. Green Chem 2010;12:22329.

[35] Ghosh PK, Mishra S, Gandhi MR, Upadhyay SC, Paul P, Anand PS. Improvedprocess for the preparation of fatty acid methyl ester (biodiesel) fromtriglyceride oil through transesterication. European Patent EP2475754.2014 Jan 1.

[36] Heywood JB. Internal combustion engine fundamentals. McGraw-Hill; 1988.[37] Dec JE. A conceptual model of DI diesel combustion based on laser-sheet

imaging. SAE Paper 970873, SAE Trans, vol. 106, 1997. p. 131948.[38] McCormick RL, Graboski MS, Alleman TL, Herring AM, Tyson KS. Impact of

Biodiesel source material and chemical structure on emissions of criteriaPollutants from heavy duty engine. Environ Sc Technol 2001;35:17427.

[39] Schonborn A, Ladommatos N, Allan R, Williams J, et al. Effect of MolecularStructure of individual fatty acid alcohol esters (biodiesel) on the formation ofNOx and Particulate Matter in the diesel combustion process. SAE Int J FuelsLubr 2008:184972.

Emissions and fuel consumption characteristics of a heavy duty diesel engine fueled with Hydroprocessed Renewable Diesel and Biodiesel1 Introduction2 Materials and methodology2.1 Production of Hydroprocessed Renewable Diesel and Biodiesel2.2 Test engine and engine dynamometer2.3 Fuel flow meter and emission analysers

3 Test cycle and methodology3.1 Test cycle3.2 Methodology3.3 Error analysis

4 Results and discussions4.1 Mass emissions results4.1.1 Specific NOx emissions4.1.2 Mode-wise NOx emission4.1.3 Particulate matter (PM) emissions4.1.4 CO and HC emissions4.1.5 Mode-wise CO and HC emissions

4.2 Fuel consumption

5 ConclusionsAcknowledgementReferences