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Technical note

Assessing idling effects on a compression ignition engine fueled withJatropha and Palm biodiesel blends

S.M. Ashrafur Rahman*, H.H. Masjuki, M.A. Kalam, M.J. Abedin, A. Sanjid,Md. Mofijur RahmanCentre for Energy Sciences, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia

a r t i c l e i n f o

Article history:Received 23 July 2013Accepted 27 February 2014Available online 22 March 2014

Keywords:BiodieselEmissionsIdlingFuel consumptionRenewable

a b s t r a c t

In this study, performance of a diesel engine operated with Jatropha and Palm biodiesel blends at highidling conditions has been evaluated. The result obtained from experiment elucidate that, at all idlingmodes HC and CO emissions of both blends decreases, however, NOx emissions increases compared topure diesel fuel. Jatropha biodiesel has higher viscosity compared to Palm biodiesel, which might havedegraded the spray characteristics and caused slightly improper mixing which might have led to slightlyincomplete combustion, thus at both idling conditions, Jatropha blends emitted higher CO and HCcompared to Palm biodiesels. Compared to diesel fuel, CO emissions were 5.9e9.7%, 17.6e22.6%, 23.5e29%, 2.9e6.4%, 5.9e14.5% and 11.8e17.74% less, HC emissions were 10.3e11.5%, 24.13e30.76%, 34.5e39%, 6.9e7.7%, 26e27% and 31e35% less and NOx emissions were 8.3e9.5%, 14e15%, 22e25%, 5e7.14%,10e11.3% and 17e18% more respectively for 5, 10 and 20% blends of Palm and Jatropha biodiesel.Compared to diesel fuel, at high idling conditions brake specific fuel consumption all Palm and Jatrophabiodieselediesel blends increased. Compared to diesel fuel, BSFC were 1.14e1.35%, 2.28e2.96%, 7.1e8.35%, 2.28e2.69%, 3.98e5.39% and 8.83e9.29% more respectively for 5, 10 and 20% blends of Palm andJatropha biodiesel.

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1. Introduction

1.1. Background

The most persuasive technological concern of both energy de-mand and supplying issues are establishing the replacement offossil fuel-derived energy resources. The detrimental impact onenvironment due to burning of fossil fuel, the unsteadiness in bothfuel demand and supply, and the relevant petroleum products’production cost hiking etc. are intensifying this issue. In 1900,Rudolph first exhibited his invention the diesel engine where Heoperated the engine with vegetable oil, “peanut oil”. However, as aresult of huge availability focuses were shifted from vegetable oilsto fuels at that time. But, currently when petroleum fuel is dwin-dling fast, researchers are looking for an alternative fuel that is eco-friendly, domestically available and technically feasible [1]. Many

countries are concentrating on a lot of researches to find a suitablereplacement of petroleum fuel [2]. One such solution can be bio-diesel as it has similar functional properties as diesel fuel [3]. Bio-diesel is biodegradable, non-explosive, renewable, non-flammable,non-toxic and also environment friendly [4]. The major advantageof using biodiesel is that, it can be used in pure form or in blendedform with diesel without making any modification [5].

Many researches has been evaluated engine performance ofvarious biodiesel and biodiesel blends [6e9] in diesel engine.However, there has been only few studies that were done toinvestigate the impact of biodiesel on engine performance andemission during high idling condition [10e12]. Engine running atlow load and at low rated speed is known as high idling conditionwhich is a major problem currently faced by the transport industry.Many researches has been done to evaluate the engine perfor-mance and emissions using only diesel fuel at idling condition.Researchers found that, NOx emission while engine idling washigher than vehicle running on road by a factor of 1.5 [13]. Increasein load during idling causes increment of NOx emission [14,15].During idling fuel consumption can be as high as 1.65 gal/h [16], COemission can be as high as 295 g/h [17], and HC emission can be ashigh as 86.4 g/h [18]. Compared to driving cycle emission HC

* Corresponding author. Department of Mechanical Engineering, University ofMalaya, 50603 Kuala Lumpur, Malaysia. Tel.: þ60 3 79674448; fax: þ60 3 79675317.

E-mail addresses: rahman.ashrafur@rocketmail.com, rahman.ashrafur.um@gmail.com (S.M.A. Rahman).

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emission during idling is reported to be 1 to 5 times more than thatof driving cycle and idling CO emission were 5%e75% of drivingemission [19].

1.2. Objectives

Diesel, Palm and Jatropha are used as fuels in this researchwork.The considered aims of the study is to study the effect of Jatrophaand Palm biodiesel blends on brake specific fuel consumption andengine emissions at high idling conditions.

2. Materials and method

2.1. Crude oil properties

In this research, Jatropha biodiesel was selected becauserecently it has drawn the attention of Malaysian Government as asource of non-edible feedstock. On the other hand, Palm wasselected due to ease of availability and rising interest due torenewability respectively. Fuel properties were measured applyingsuitable measuring techniques and devices. Table 1 shows physico-chemical properties of crude Jatropha and Palm oil.

2.2. Biodiesel production process

If the crude oil contains higher FFA then two step processes isrequired. As the acid value of crude Jatropha oil was much highertwo step (acid-base catalyst) processes were selected, but for Palmoil only transesterification process were selected as its acid valuewas within the limit. For the production of biodiesel 1 L batchreactor was used in the laboratory.

Acid-catalyzed process e In this process, the molar ratio ofmethanol to refined crude oil was maintained at 12:1 (50% v/v).1% (v/v) of sulfuric acid (H2SO4) was added to the pre-heatedoils at 60 �C for 3 h under 400 rpm stirring speed in a glass

reactor. The products were poured into a separating funnel toseparate the excess alcohol, sulfuric acid and impurities pre-sented in the upper layer. The lower layer was separated andentered into a rotary evaporator and heated at 95 �C undervacuum conditions for 1 h to remove methanol and water fromthe esterified oil.

Alkaline-catalyzed processe In this process, the esterified oil wasreacted with methanol (6:1 M ratio) and 1% (m/moil) of potassiumhydroxide (KOH) and maintained at 60 �C for 2 h and 400 rpmstirring speed. After completion of the reaction, the producedbiodiesel was deposited in a separation funnel for 12 h to separateglycerol from biodiesel. The lower layer which contained impuritiesand glycerol was drawn off.

2.3. Fatty acid composition

Fatty acid with and without double bond is known as unsatu-rated and saturated fatty acid respectively. The fatty acid compo-sition (FAC) of Jatropha and Palm biodiesel was tested using gaschromatography (GC). Table 2 shows the operating conditions ofthe GC. The results of FAC of Jatropha and Palm biodiesel is shown inTable 3.

2.4. Properties analysis

The physico-chemical properties of the produced biodiesel werecharacterized according to the ASTM D6751 standards. Each prop-erty test was repeated three times.

Saponification Number, Cetane number and Iodine value werecalculated by using the fatty acid composition results and thefollowing empirical equations (1)e(3) respectively [20,21]

SN ¼X560*Ai

MWi(1)

List of acronyms

% vol percentage volumeBSFC brake specific fuel consumptionCN cetane numberCO carbon monoxideFAC fatty acid compositionFFA free fatty acidg/kWh grams per kilowatt hourGC gas chromatographyHC hydrocarbonIV iodine value

JB10 10% Jatropha biodiesel þ 90% dieselJB20 20% Jatropha biodiesel þ 80% dieselJB5 5% Jatropha biodiesel þ 95% dieselMJ/kg mega joules per kilo-gramNOX nitrogen oxidesPB10 10% Palm biodiesel þ 90% dieselPB20 20% Palm biodiesel þ 90% dieselPB5 5% Palm biodiesel þ 95% dieselppm vol parts per million volumeSN saponification valuev/v volume per volume

Table 1Properties of crude Jatropha and palm oil.

Properties Units Standards Jatropha oil Palm oil

Kinematicviscosity at 40 �C

mm2/s ASTM D445 51 39.43

Density at 15 �C kg/m3 ASTM D4052 917 901Flash point �C ASTM D93 218 169Pour point �C ASTM D97 5 9Cloud point �C ASTM D2500 10 8Calorific value MJ/kg ASTM D240 38.66 39.45Iodine value g Iodine/100 g e 95 57Acid value Mg KOH/g oil e 11 3.6Cetane number e ASTM D613 46 54

Table 2GC operating conditions.

Property Specifications

Carrier gas Helium at 23.8 psiLinear velocity 44 cm/s @ 100 �CFlow rate Air ¼ 450 ml/min

H2 ¼ 40 ml/minHe ¼ 20 ml/min

Detector temperature 250 �CColumn head pressure 23.8 psiColumn dimension 30 m � 250 mm � 2.5 mmInjector Split injector, 50:1 ratio, 0.3 mL injection volumeTemperature ramp 1 100 �C hold for 0 minTemperature ramp 2 10 �C/min to 250 �C, hold for 5 min

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IV ¼X254*D*Ai

MW(2)

CN ¼ 46:3þ�5458SN

�� ð0:225*IVÞ (3)

where Ai is theweight percentage of each fatty acid component,D isthe number of double bonds present in each fatty acid and MWi isthe molecular weight of each fatty acid component.

3. Blending of biodiesel

The test fuels are blended at various ratios by using a homog-enizer device at a speed of 2000 rpm. The homogenizer was fixedon a clamp on a vertical stand, which allows changing of the ho-mogenizer’s height.

4. Engine test

The engine test was done with an in-line four cylinder CI enginewhich was coupled with an eddy current dynamometer. Two idlingconditions (1000 RPM 10% load and 1200 RPM 12% load) wereconsidered in this investigation. 5%, 10% and 20% (PB5, JB5, PB10,JB10 and PB20, JB20) blends of Jatropha and Palm along with dieselfuel have been used to run the engine. Also, to depict the effect ofidling, engine was operated at 100% load and 2000 RPM andmeasured data were compared with the idling data. Schematicdiagram of the engine setup is given in Fig. 1. Table 4 and Table 5shows engine specification and test equipment respectively. Forcombustion analysis a pressure sensor and a crank angle encoder

(RIE-360) have been used. These two sensors together provides thein-cylinder pressure variation with crank angle. Digital data havebeen recorded in a computer using a software name DEWESoftCombustion Analyzer.

5. Results and discussion

5.1. Fuel properties

Table 6 which shows the important physico-chemical propertiesof Jatropha and Palm biodiesel. The major physico-chemical prop-erties of Jatropha and Palm biodiesel are comparable with those ofdiesel fuel.

The densities of all the biodiesels were found to be higher thandiesel fuel, as expected. Kinematic viscosity is influenced by thefatty acid profile of the biodiesel [22]. As seen from Table 4, thekinematic viscosity levels of the biodiesel satisfied ASTM standards.Jatropha biodiesel have slightly higher kinematic viscosity(4.74 mm2/s) compared to Palm biodiesel (4.65 mm2/s). Also,density of Jatropha biodiesel (867 kg/m3) is higher than Palm bio-diesel (857 kg/m3). The calorific values of all biodiesels were, asexpected, found to be less than diesel fuel, Jatropha biodiesel have alower calorific value of 39.827 MJ/kg whereas Palm biodiesel have39.9 MJ/kg. Flash point of all the biodiesels were found to be much

Table 3Fatty acid composition of Jatropha and Palm biodiesel.

Fatty acid Molecularweight

Structure Systematic name Formula JBD(Wt %)

PBD(Wt %)

Lauric 200 12:0 Dodecanoic C12H24O2 0.1 e

Myristicacid

228 14:0 Tetradecanoic C14H28O2 0.1 e

Palmitic 256 16:0 Hexadecanoic C16H32O2 13.9 39.9Palmitoleic 254 16.1 Hexadec-9-enoic C16H30O2 0.5 e

Stearic 284 18:0 Octadecanoic C18H36O2 7.3 4.3Oleic 282 18:1 cis-9-

OctadecenoicC18H34O2 43.5 42.8

Linoleic 280 18:2 cis-9-cis-12Octadecadienoic

C18H32O2 32 11.8

Linolenic 278 18:3 cis-9-cis-12 C18H30O2 0.2 e

Arachidic 312 20:0 Eicosanoic C20H40O2 0.4 e

Fig. 1. Schematic diagram of the engine test bed.

Table 4Engine specification.

Engine type 4 cylinder inlineDisplacement 2.5 L (2476 cc)Bore 91.1 mmStroke 95.0 mmInjection system Direct, naturally aspiratedTorque Max. 132 N-m, at 2000 rpmPower Max 50 kW at 4000 rpmCompression Ratio 21:1Injection pump Common rail mechanically controlled

Table 5Equipment used in engine test.

Equipment name BOSCH BEA-350 exhaust gas analyzerMeasured HC (parts per million or ppm)

Carbon monoxide (percentage volume or %vol)Carbon dioxide (percentage volume or %vol)

Equipment name AVL 4000 (Manufacturer: Graz/Austria)Measured NOx (parts per million or ppm)Equipment name DYNOMAX 2000 data control systemMeasured Exhaust gas temperature (EGT)

Brake specific fuel consumption (BSFC)

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higher than the ASTM standards (Jatropha 186 �C, Palm 181 �C)which makes them safe for use. Pour point value indicates thepumpability, as it indicates the waxy nature of the oil. Pour pointsof all the tested fuels were within ASTM standards (Jatropha 3 �C,Palm 11 �C). The cloud point has much greater importance incountries where the weather is cold. Cloud point of all the testedbiodiesels were within the ASTM limit (Jatropha 4 �C, Palm 10 �C).Cetane value indicates the duration of ignition delay period, highercetane number means lower ignition delay. Palm biodiesel havehigher cetane number (59.5) compared to Jatropha biodiesel (51.7).

5.2. CO emission

Fig. 2 depicts that, at all idling modes, Diesel fuel emittedhighest CO emission compared to both Palm and Jatropha biodieselblends. Secondly, Jatropha biodiesels blends emitted more COcompared to Palm biodiesel blends. Compared to diesel fuel, COemissions for PB5, PB10, PB20, JB5, JB10 and JB20 were 5.9e9.7%,17.6e22.6%, 23.5e29%, 2.9e6.4%, 5.9e14.5% and 11.8e17.74% lessrespectively. Compared to Palm biodiesel blends, Jatropha biodieselblends showed less decrease of CO emissions due to the reason thatJatropha biodiesel has higher viscosity compared to Palm biodiesel,which might have degraded the spray characteristics and causedslightly improper mixing which might have led to incompletecombustion.

5.3. HC emission

Fig 3 represents HC emissions at different idling conditions ofPalm and Jatropha biodiesel blends compared to diesel fuel. It canbe seen that, diesel fuel emits highest amount of HC at all condi-tions. From the figure it can be seen that, HC emissions follow the

trends of CO emissions. Increase in blend percentages decreases HCemissions. As there is higher oxygen concentration in the bio-dieselediesel blends which enhances the oxidation of unburnedhydrocarbons, HC emission decreases with increase in percentagesof biodiesel blends. Furthermore, increase in speed decreases HCemission for all tested fuel. This is due to the reason that increase inspeed ensures better mixing of air and fuel. Compared to diesel fuel,HC emissions for PB5, PB10, PB20, JB5, JB10 and JB20 were 10.3e11.5%, 24.13e30.76%, 34.5e39%, 6.9e7.7%, 26e27% and 31e35% lessrespectively.

5.4. NOx emission

Fig 4 demonstrates NOx emission at different idling conditionsfor diesel, Palm and Jatropha biodiesel blends. Diesel fuelexhibited lowest emission at all condition. As blend percentagesof biodiesel increases emission increases. Biodiesel blends pro-duce higher emission due to having higher cetane number andlower ignition delay. It is observed that, as idling speed increasesemission decreases due to the fact that increase in speed reducesthe ignition delay which results in less amount of time to formNOx. Also, compared to diesel fuel, biodiesels are more oxygen-ated fuel and contains 12% more molecular oxygen than diesel,which raises chamber temperatures and improves combustionthus NOx emissions increases [20]. Compared to diesel fuel, NOxemissions for PB5, PB10, PB20, JB5, JB10 and JB20 were 8.3e9.5%,14e15%, 22e25%, 5e7.14%, 10e11.3% and 17e18% more respec-tively. Compared to Jatropha blends, Palm biodiesel blends emitshigher NOx. As, Palm biodiesel have higher cetane numbercompared to Jatropha biodiesel, ignition delay is shortercompared to Jatropha. As a result, the fuel mixture and initialcombustion products have a longer residence time at elevated

Fig. 2. CO emissions at different idling conditions for diesel, Palm and Jatropha bio-dieselediesel blends.

Fig. 3. HC emissions at different idling conditions for diesel, Palm and Jatropha bio-dieselediesel blends.

Table 6Major physico-chemical properties of Jatropha and Palm biodiesel compared to diesel.

Properties Units Standards ASTM D6751 JBD PBD Diesel

Kinematic viscosity at 40 �C mm2/s ASTM D445 1.9e6 4.74 4.65 3.619Density at 15 �C kg/m3 ASTM D1298 860e900 867 857 832.8Flash point �C ASTM D93 >130 186 181 77Cloud point �C ASTM D2500 e 4 10 �20Pour point �C ASTM D97 e 3 11 �35Sulfur content ppm ASTM D5433 0.05% 4.59 5.09 e

Calorific value (lower) MJ/kg ASTM D240 e 39.827 39.9 44.66Iodine value g I/100 g EN 14111 120 max 98 60 e

Saponification value e e e 197 204 e

Acid value mg KOH/g ASTM D664 0.05 0.05 0.05 e

Oxidation stability h EN ISO 14112 3 3.02 3.5 110Cetane number e ASTM D613 47 min 51.7 59.5 48

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temperature, thus emits higher NOx compared to Jatropha bio-diesel blends.

There has been several studies that tried to investigate howbiodiesel affect combustion phasing and influences NOx emissions.Combustion period can be sub-divided into three separate periods:ignition delay period, pre-mixed combustion period, and diffusioncombustion period. The ignition delay period is the time betweenstart of injection and start of ignition. This period is related to thecetane number of the fuel, with higher cetane leading to shorterignition delay. Typically, biodiesel fuels have higher cetanenumbers than petroleum diesel [23,24]. A shorter ignition delaycould allow the fuel mixture and initial combustion products tohave a longer residence time at elevated temperature, therebyincreasing thermal NOx formation. Again, during the pre-mixedcombustion period, fuel and air that have already mixed ignite,causing a rapid rise in temperature and pressure. The extent towhich these temperature and pressure increases occur dependsupon the amount of fuel that has already been injected, which isrelated to the length of the ignition delay. With longer ignitiondelays (related to low cetane number), more fuel is injected andmixedwith air before ignition occurs, thus leading tomore extremetemperature and pressure increases. And thus increases NOxemission.

5.5. Brake specific fuel consumption

Brake Specific Fuel Consumption (BSFC) is considered ameasureof combustion efficiency, how efficiently a given amount of fuel isbeing converted into a specific amount of horsepower. Fig. 5 showsthe brake specific fuel consumption at different idling conditionsfor diesel, Palm and Jatropha biodiesel blends. At all conditions

diesel fuel consumption rate was lowest, and as blend percentagesincreased BSFC increased due to having lower heating valuecompared to diesel fuel. From fig it is also evident that increase inidling speed, BSFC increases, as increase in idling speed results inmore fuel consumption. Compared to diesel fuel, BSFC for PB5,PB10, PB20, JB5, JB10 and JB20 1.14e1.35%, 2.28e2.96%, 7.1e8.35%,2.28e2.69%, 3.98e5.39% and 8.83e9.29% more respectively.

5.6. In-cylinder pressure

As biodiesel have higher cetane number, at the initial stage,combustion starts earlier compare to diesel fuel. Thus, heat releaserate of biodiesel blends is higher than diesel fuel. Thus, biodieselblends achieve higher peak pressure than diesel fuel. Figs. 6 and 7depicts the in-cylinder pressure of a) Palm and b) Jatropha biodieselblends compared to diesel fuel.

When the engine is running at low load, residual gas tempera-ture and wall temperature are low. Therefore, injection chargetemperatures are also significantly low, which in turns increasesinjection delay period. Thus for diesel fuel combustion starts latercompared to biodiesel and its blends. Consequently, for diesel fuel,the peak cylinder pressure reaches a lesser value further away fromthe top dead center in the expansion stroke. Again, for biodiesel andits blends peak cylinder pressure take place earlier. From these twofigures it can be depicted that, at both idling modes, Palm andJatropha biodiesel blends exhibited higher peak pressure comparedto Diesel fuel.

5.7. Error analysis

Experimental error and uncertainty can arise from instrumentselection, condition, calibration, environment, observation,reading, and test planning. Uncertainty analysis is thus required in

Fig. 4. NOx emissions at different idling conditions for diesel, Palm and Jatrophabiodieselediesel blends.

Fig. 5. Brake specific fuel consumption at different idling conditions for diesel, Palmand Jatropha biodieselediesel blends.

Fig. 6. In-cylinder pressure vs. crank angle variation compared to diesel and a) Palmand b) Jatropha Biodiesel blends at idling mode 1.

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order to prove the accuracy of the experiments. Table 7 displays asummary of measurement accuracy and the relative uncertainty ofvarious parameters, including fuel consumption, CO, HC, and NOxemission.

6. Conclusions

Biodiesel has been produced from Palm and Jatropha oil and itsproperties have been evaluated in the lab. Also, an unmodifieddiesel engine was operated with Diesel, Palm and Jatropha bio-dieselediesel blends at high idling conditions and engine perfor-mance and emissions weremeasured.10% and 20% biodiesel blendswere used the most important outcomes derived are summarizedas follows:

➢ As biodiesel produced from both Palm and Jatropha curcassatisfied the ASTM standards it can be used along with dieselfuel.

➢ Jatropha biodiesel have slightly higher kinematic viscosity(4.74 mm2/s) compared to Palm biodiesel (4.65 mm2/s).

➢ Jatropha biodiesel have a lower calorific value of 39.827 MJ/kgwhereas Palm biodiesel have 39.9 MJ/kg, which both are lessthan diesel fuel, as expected.

➢ As biodiesel have higher oxygen content they ensures bettercombustion, thus less CO and HC emission compared to dieselfuel. At both idling modes, Diesel fuel exhibited highest CO andHC emissions at both idling conditions.

➢ Jatropha biodiesel has higher viscosity compared to Palm bio-diesel, which might have degraded the spray characteristics andcaused slightly improper mixing which might have led toslightly incomplete combustion, thus at both idling conditions,Jatropha blends emitted higher CO and HC compared to Palmbiodiesels.

➢ Compared to diesel fuel, CO emissions for PB5, PB10, PB20, JB5,JB10 and JB20 were 5.9e9.7%, 17.6e22.6%, 23.5e29%, 2.9e6.4%,5.9e14.5% and 11.8e17.74% less respectively.

➢ Compared to diesel fuel, HC emissions for PB5, PB10, PB20, JB5,JB10 and JB20 were 10.3e11.5%, 24.13e30.76%, 34.5e39%, 6.9e7.7%, 26e27% and 31e35% less respectively.

➢ However, higher oxygen content results in higher NOx emis-sions. At both idling conditions, Diesel fuel emitted lowest NOx.

➢ Palm biodiesel have higher cetane number compared to Jatro-pha biodiesel, ignition delay is shorter compared to Jatropha,thus emits higher NOx compared to Jatropha biodiesel blends.

➢ Compared to diesel fuel, NOx emissions for PB5, PB10, PB20, JB5,JB10 and JB20 were 8.3e9.5%, 14e15%, 22e25%, 5e7.14%, 10e11.3% and 17e18% more respectively

➢ Compared to diesel fuel, at high idling conditions brake specificfuel consumption all Palm and Jatropha biodieselediesel blendsincreased.

➢ With the increase of blend percentages brake specific fuelconsumption of biodiesel increases.

➢ Compared to diesel fuel, BSFC for PB5, PB10, PB20, JB5, JB10 andJB20 1.14e1.35%, 2.28e2.96%, 7.1e8.35%, 2.28e2.69%, 3.98e5.39% and 8.83e9.29% more respectively.

➢ At both idling condition PB20 emitted lowest CO and HC emis-sions, however, also emitted highest NOx emissions too. And,Brake specific fuel consumption of JB20 was highest at bothcondition.

Acknowledgment

The authors would like to appreciate University of Malaya forfinancial support through High Impact Research grant titled: CleanDiesel Technology for Military and Civilian Transport Vehicleshaving grant number UM.C/HIR/MOHE/ENG/07.

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Table 7Relative uncertainty for parameters brake specific fuel consumption, CO, HC and NOx

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Measurements Accuracy Relative uncertainty Reading (diesel,idle mode 1)

BSFC �5 g/kWh (�5/351) ¼ 0.014 351 g/kWhCO �0.001 vol% (�0.001/0.68) ¼ 0.00147 0.68 %volHC �1 ppm (�1/29) ¼ 0.034 29 ppmNOx �1 ppm (�1/180) ¼ 0.00555 180 ppm

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