Journal of Mechanical Engineering and Auomaion 16, 6(1): 1-7 DOI:.5923/j.jmea.160601.01 The Comparison Cos of EVs Charging via Plug-in Elecriciy and Gasoline Source Mukhar M. A. Morad 1, Ahmad Murad 1, Abdulwahab Ali Alnaqi 1,*, Hasan Mulla Ali 1, Esam AM Husain 1, Ahmad Alkandari 2 1 Deparmen of Auomoive and Marine Engineering Technology, College of Technological Sudies - PAAET, Kuwai 2 Deparmen of Elecrical Engineering Technology, College of Technological Sudies - PAAET, Kuwai Absrac The wo major areas of engine developmen in he auomobile indusry is concenraing and puing is major developmen effor on he emission conrol and improve fuel efficiency. The objecive of his sudy is o develop a mehodology and ypically o validae he resuls wih experimenal daa, his developmen eiher direcly or indirecly impac he vehicle performance requiremen significanly, during he es carried ou under differen running condiion, he resuls shows he elecric vehicles (EVs) have beer operaion especially in urban area. The heoreical analyical calculaion have been performed for boh pure elecrical and mechanical vehicles, his sudy will help o compare he consumpion cos here by saving ime and effor o choose he lower running cos. Keywords Elecric vehicles, Fuel consumpion, Experimenal analysis 1. Inroducion The inernal combusion engines powered vehicles have been in consan use ever since hese where invened. There have been many innovaions and developmens in he design and manufacure of such vehicles. However, in recen years i has become apparen ha oday s fuel powered vehicles are far from ideal for urban use. These no only produce air polluion, bu also suffer from poor fuel efficiency [1]. The sringen regulaions imposed upon manufacurers regarding clean air and oher environmenal problems due o widespread usage of auomobiles like raffic noise level, raffic jam, parking difficulies and also he hreaening shorages of hydrocarbon fuels, he disribuion of world s oil supplies in 1973 and he soaring oil prices of 1978 have led o serious consideraions by researchers and planners o shif owards alernaive energy resources, for he ranspor area [2]. There have been considerable reseach on purely elecric vehicles since he inroducion of auomobiles and, in fac, he world s firs auomobuile were propelled by elecriciy and i was an elecric car ha so he firs official world speed record in 1898 [2, 3]. Improvemen in baeries weigh reducion migh be aracive for widespread accepance. Elecric vehicle differ from fossil fuel-powered * Corresponding auhor: aa.alnaqi@paae.edu.kw (Abdulwahab Ali Alnaqi) Published online a hp://journal.sapub.org/jmea Copyrigh 16 Scienific & Academic Publishing. All Righs Reserved vehicles in ha he elecriciy consumers can be generaed from many sources, even when power is generaed using fossil fuels, elecric vehicles usually compared o gasoline vehicle, show significan reducions in emission, and quier operaion [4]. The presen work was aimed o compare beween EVs and convenional inernal combusion engine from fuel consumpion poin view. 2. Elecriciy Sources There are many ways o generae elecriciy, of varying coss, efficiency and ecological desirabiliy. Direc connecion o generaion plan such as generaed on board using a gasoline engine coupled o elecric generaor plan (nearly always when saionary) and hen disconneced before moion occurs and he elecriciy is sored in he baery unil needed. Anoher form of charging he baery, using elecric charger, his sysem direcly connecing o he main source o uilize any exernal source of elecriciy sored in he rechargeable baery o drive he wheels. 2.1. Baery Types and Specificaion a) Lihium-ion Baery Lihium-Ion (and similar Lihium polymer) baery, widely known hrough heir use in lapops and consumer elecronics, dominae he mos recen group of EVs in developmen. The mos EVs are uilizing new variaions on lihium-ion for he reasons provide fine resisance, environmenal friendliness very rapid charge (as low as a few minues) and very long life spans. These varians
Baery Volage (v) 2 Mukhar M. A. Morad e al.: The Comparison Cos of EVs Charging via Plug-in Elecriciy and Gasoline Source (phosphaes, iamaes, spinels) have been shown o have a much longer lifeime, wih A123 expecing heir lihium-ion phosphae baeries o las for a leas + years and 7000+ charge cycles [5], and LG chem expecing heir lihium manganese spirel baeries o las up o 40 years. Much work is being done on lihium ion baeries in he lab. o overcome he inconvenien siuaion occurs during vehicle operaions. b) Lead-acid Flooded lead-acid baeries are he cheapes and mos common racion baeries available. There are wo main ypes of Lead-acid baeries, auomobile engine sarer baeries and deep cycle baeries. Auomobile alernaors are designed o provide sarer baeries high charge raes for fas charges, while deep cycle baeries used for elecric vehicles like forklifs or golf cars, and as he auxiliary house baeries in RVs, require differen muli-sage charging, bu deep cycle lead baeries are expensive and have a shorer life han he vehicle iself, ypically needing replacemen every 3 years. Lead-acid baery should no be discharged below 50% of is capaciy, as i shorens he baery life. Flooded baeries require inspecion of elecrolye level and occasional replacemen of waer which gasses escape away during he normal charging cycle. Mos elecric vehicles have used Lead-acid baeries due o heir maure echnology, high availabiliy and low cos. Like all baeries hese have an environmenal impac hrough heir consrucion, use disposal or recycling. On he upside, vehicle baery recycling raes op o 95% in he Unied Saes. Charging and operaion of baeries ypically resuls in he emission of hydrogen, oxygen and sulfur, which are naurally occurring and normally harmless. If no vened properly, unpleasan sulfur smells would leak ino cabin immediaely afer charging [5-6]. c) ickel Meal hydride ickel meal hydride baeries are now considered a relaively maure echnology. While less efficien (60-70%) in charging and discharging han even lead-acid, hey boas an energy densiy of -80 wh/kg. far higher han lead-acid. When used properly, ickel-meal hydride baeries can have excepionally long life has been demonsraed in heir use in hybrid cars and surviving imhrav 4EVs ha sill operae well afer 0,000 miles (160.000 km) and over a decade of service. Downsides include he poor efficiency, high self-discharge, very finicky charge cycle and poor performance in cold weaher [6]. 3. Theoreical Analysis 3.1. Performance Characerisics of Baery The baery applied consis of 8 cells. The baery used was 0 Ampere-Hour. (hour raing) 24 vol having ouside dimensions of 28 14.5 23.4 cm and ne weigh of 25.6 kg having 3.v per cell. The baery performance was evaluaed by esing he baery during charging and during discharging wih differen discharge raes. The baery was charge by means of elecric generaor or plug-in elecriciy and a porable baery charger whose capable of supplying a maximum charging curren of 0 amps. During charging he baery volage was recorded unil he value of he relevan volage remained unchanged. This indicaed ha he baery was fully charged. Fig (1) shows he es rig used for baery discharge. The variable resisance in his figure was adjused during discharging in order o mainain a consan discharge rae. The baery volage and ambien emperaure were recorded during discharging. Tes was carried ou o give he change of baery volage wih baery capaciy from he differen discharge raes refereed o Fig (2). Evidenly he baery capaciy decreases wih increase of discharge rae. Also he variaion of baery volage, baery capaciy and mean baery power obained wih differen discharge currens. In addiion o he variaion of charger volage, baery volage, charging curren wih ime during baery charging wih he normal charging rae [7]. 25 15 5 Figure 1. Tes Rig for Baery Discharge 0 0 40 60 80 0 1 Baery Capaciy (AH) Figure 2. Baery Volage vs Baery Capaciy Baery power is vary hroughou he working operaion during he es drive by changing he load (changing he curren) since he baery volage is 24 vol a fully charge, while he curren is varying accordingly power will be
Moor Torque (.M) Baery Power (KW) Baery Volage (v) Journal of Mechanical Engineering and Auomaion 16, 6(1): 1-7 3 change. Fig (3), Fig (4). 25 15 5 0 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Figure 3. Baery Volage vs Discharge Curren Figure 4. Baery Power vs Discharge Curren Since Amp hours is how much charge is sored in he baery, if muliplying he average or nominal baery volage imes he baery capaciy in amp-hours gives how many wa-hours he baery conains [8]. 40 50 60 70 80 90 0 1 Discharge Curren (A) 40 50 60 70 80 90 0 1 Discharge Curren (A) E = C. Vavg (1) E = he energy sored in wa-hours C = baery capaciy in amp-hours Vavg = is he average volage during discharge Where he baery discharged quickly, baery efficiency will reduce. A ypical sealedlead-acid baery will give only half of is raed capaciy when discharged a he C/1 rae compared wih he C/ rae. If he curren drawn is x amps, he ime is T hours hen he capaciy C in amp- hours is C = XT. (2) If a device is drawing 1mA and i should run for 24 hours C = 0.12 Amp. 24 Hours = 2.88 amp hours I is no good o run a baery all he way down o zero during each discharge cycle. In he case of lead Acid baery you shouldn' run i pos 80% of is charge, Leaving % lef in he baery. This no only exends he number of cycles you ge, bu les he baery degrade by % before you sar geing less run ime han he design calls for for he above example C' = 2.88/0.8 = 3.6 AH C' = C/0.8 (3) Then if we ake he high rae ino accoun C" = 3.6/0.5 = 7.2 AH Thus we need a 7.2 amp hour sealed lead acid baery o run he device for 1 hour a amps average. 3.2. Performance Characerisics of Torquer The orquer should be esed a consan erminal D.C volage of 12, 18, 24 vol,. These erminal volage are equivalen o hese prevailing when he car is working, he orquer is fed from he baery. The orquer load is vary according o he driving condiions. The following es configuraions were applied [9, ]. 1-Supply volage 18v Fig (5) gives he variaion of he moor orque agains he moor speed while Fig (6) indicaes he corresponding change of moor power wih moor speed. And Fig (7) shows he associaed variaion of he moor efficiency wih moor speed. 80 70 60 50 40 0 00 1400 1600 1800 00 20 2400 2600 Moor Speed (RPM) Figure 5. Moor Torque vs Moor Speed 18 vol 24 vol
Charging Curren (A) Charger Volage (v) Moor Efficiency % Moor Power (KW) Baery Volage (v) 4 Mukhar M. A. Morad e al.: The Comparison Cos of EVs Charging via Plug-in Elecriciy and Gasoline Source 3.0 2.5 2.0 1.5 1.0 0.5 0.0 00 1400 1600 1800 00 20 2400 2600 0 90 80 Moor Speed (RPM) Figure 6. Moor Power vs Moor Speed 18 vol 24 vol 18 vol 24 vol Po Thus he efficiency of orquer = 0.95 P I is ineresing o compere he fuel cos where using he engine wih ha obained under all elecric vehicle i.e when applying he elecric moor. To obain he cos of baery charging, referring o fig (8) where he variaion of charger volage, baery volage and charging curren Fig (9) where charging he baery from a commercial charger a a moderae rae of charging, is given as: Charging ime = 4 hours Mean charging curren o he baery = Amp. Mean charging volage = 25 vol Mean value of A.C. volage feeding charger = 225v Mean value of A.C curren feeding charger = 4 Amp. D.C. charging energy for he baery = ( VI ) D. C = 00 wh A.C. charging energy for one baery = ( VI cos ) A. Assuming a power facor cos 0. 8 for he charger A.C charging energy for he baery = 2880 wh Thus he efficiency of he charger is 0.7 C 70 60 28 28 50 40 26 26 00 1400 1600 1800 00 20 2400 2600 Moor Speed (RPM) 24 22 24 22 2-Supply Volage 24v Figure 7. Moor Efficiency vs Moor Speed Fig (5) gives he variaion of he moor orque agains he moor speed while Fig (6) indicaes he corresponding change of moor power wih moor speed. And Fig (7) shows he associaed variaion of he moor efficiency wih moor speed. The following example classifies he mehod of soluion adaped o compue he orquer efficiency. Speed of orquer = 00 R.P.M Live volage of orquer v 24 vols Curren consumed by orquer I = 95 Amp. v P Power inpu of orquer P K. W 00 2.28 Power absorbed by The E P K.W Assuming a ransmission efficiency of 96% when he v working on level road and consan speed. In his case he power of he orquer is equal o he power absorbed by EV Ev P o. o E v Figure 8. 0 98 96 94 92-1 0 1 2 3 4 5 6 7 Time (Hr) Variaion of Charger Volage and Baery Volage wih Time 90-1 0 1 2 3 4 5 6 7 Time (Hr) Figure 9. Charging Curren vs Time
Brake Power (kw) Journal of Mechanical Engineering and Auomaion 16, 6(1): 1-7 5 This gives a reasonable value for he charger efficiency. However assuming a charger efficiency of 0.8 which is generally used for baery charging & using he local energy cos of 2 fils/kwh he cos of charging he baery = 5.76 fils. Referring o Fig () he inpu power required o run he car a a consan speed of 40 Km/h on he level road = 2.4 k.w For a car speed of 40 km/h., engine speed applying, he given 40 d e formula. 3.0 60 ig Thus he disance covered during ha ime is km 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 5 15 25 35 40 45 Car Speed (km/hr) Figure. Brake power vs Car speed Also he cos of elecrical energy supplied during ha ime excluding, he cos of baery, moor and conrol sysem depreciaion is 5.76 fils. Thus compared o he Perol, he perol cos a he presen ime in Kuwai is 65 fils/li for 95 ocane number accordingly he energy cos where using he engine will be 1.56 fils/km [11]. Evidenly his sum gives he fuel cos only irrespecive of all cos such as mainenance, depreciaion ec. 3.3. The Performance Characerisics of he Car The specificaions of he car, ha has been seleced, have been given in Appendix (1). The racion characerisics of his car are compued hroughou he following procedures. In he case of his car he power required is equal o he fuel consumpion a differen speeds for consan disance on level road [12]. Deerminaion of car fuel consumpion:- 1) Car running on level road wih consan speed: The car fuel consumpion is esimaed a differen consan speeds varying from -50 km/h, when he car ravelling on he level road and assuming using a perol engine o compose he running cos for differen modes of operaion, elecric or mechanical. A sample of he relevan calculaions is given in he following par for one of he reference car speed generally applied in case of he given car [13, 14]. Car fuel consumpion a 40 km/h The car racive effor, F is given by Fr = Rolling resisance Fa = Air resisance Fi = Ineria resisance Fg = Gradien resisance F = Fr + Fa + Fi + Fg (4) Since he car runs on he level road wih consan speed, he racive effor is given by F = Fr + Fa (5) The rolling resisance when he car is running on he level road is given by - W = Car weigh = 250 kg fr = coefficien of rolling resisance Fr = fr.w (6) The coefficien of rolling resisance is deermined from Andreau's relaionship as given by: 3 3.7 v f r 0.69 6 1.44 (7) P 1.294 P P = Inflaion pressure (kp/cm 2 ) v = car speed (km/h) In he presen case wih P = 6.8 kp/cm 2 V = 40 km/h fr = 0.0761 Fr = fr w = 186.6 In case of a car speed of 40 km/h he air resisance. eq. is given by F a Cd = Drag coefficien = Air densiy A = Car fronal area V = car speed Cd 2 2 AV (8) Taking Cd = 0.43 and = 1.15 kg/m 3 a average amosphere condiions Fa = 0.25 A V2 The value of A is compued from he empirical formula - A = 0.78 B.H (9) B = car widh = 1 cm H = car heigh = 65 cm Thus A = 0.608 m 2 And Fa = 0.152 123.4 Fa = 18.7 he racive effor F = Fr + Fa = 5.3
6 Mukhar M. A. Morad e al.: The Comparison Cos of EVs Charging via Plug-in Elecriciy and Gasoline Source F. v The racive power P ( Kw) () 00 v = car speed m/s P 2.28 Kw Also he engine brake power = P (11) = Transmission efficiency Assuming a ransmission efficiency of 95% on his speed The engine brake power = 2.4 Kw Bu he car speed v = d = Tire diameer [m] e = engine speed ig = overall gear raios Thus e = 2136 r.p.m Bu he engine brake power d. e 60ig (12) d 2 2 c L e Pm n Pb ( ) 4260 Kw (13) n = umber of engine cylinders = 1 dc = cylinder diameer = 0.06 m L = Engine sroke = 0.06 m Pm = B.M.E.P = Brake mean effecive pressure bar For brake power Pb = 2.4 kw Thus Pm = 7.9 bar From he performance map given in Fig (11) a he given values of e & Pm, he brake specific fuel consumpion (B.S.F.C) = 290 g/kwh 0.7 kg/h Bu he car fuel consumpion f M f 0 V = fuel densiy = 0.7294 kg/l V = Car speed (km/h) f L/0 km Thus he car fuel consumpion = 2.4 L/0 km 4. Conclusions (15) The fuel economy of an auomoive is he fuel efficiency relaionship beween he disance ravelled and he amoun of fuel consumed by he vehicle. The objecive of his sudy described in his paper was o invesigae he fuel consumpion as a funcion of a consan disance hroughou he es for pure mechanical mode. Pure mechanical or all elecrical vehicle was esed for he same disance hroughou he es under he same condiion. In his sudy a mehodology was developed o validae he calculaed resuls wih experimenal daa, his developmen eiher direcly or indirecly impac he vehicle performance requiremen significanly, during he es carried ou under differen running condiion, he resuls shows he elecric vehicles (EVs) have beer operaion especially in urban area. The cos analysis based on he fuel consumpion involving he operaion of mechanical modes has been done, he fuel cos has been considered irrespecive of all oher coss such as mainenance, depreciaion..ec. In he elecrical mode, he comparable cos excluding he cos of he baery, moor and conrol sysem depreciaion has been compued. I has been shown ha he energy cos for purely elecrical model is only 37 percen of he cos of purely mechanical mode. This migh be due o prevailing lower cos elecriciy sales in Kuwai a presen. Appendix (1) Figure 11. Performance Map Showing Variaions of Brake Mean Effecive Pressure & Brake Specific Fuel Consumpion wih Engine Speed Thus he engine fuel consumpion M f B. S. F. C Pb = 290 2.4 = 696 g/h (14) Baery and car specificaion A) Baery 8 cells baery applied Max. curren 0 Amp Hour Dimensions 28 14.5 23.4 cm 24 vol 3. vol per cell e weigh 25.6 kg. B) Car Curb weigh Max. pay load Overall lengh Overall widh : 180 kg :250 kg : 260 cm : 1 cm
Journal of Mechanical Engineering and Auomaion 16, 6(1): 1-7 7 Overall heigh Wheel base Tread fron/rear Ground clearance C) Engine : 80 cm : 155 cm : 2 cm : 12 cm Bore : 0.6 cm Sroke : 0.6 cm o. of cylinder : 1 Engine displacemen : 0 cm 3 Comp. raio : 9:1 Max. horse power : H.P Max. orque :22.m REFERECES [1] Fuel economy in auomobiles-from Wikipedia he free encyclopedia. [2] Plug- in Elecric vehicles (PEVs), Cener for Susainable Energy California. Rerieved -03-31. [3] David B. Sandalow. Ed (09) Plug- In Elecric vehicles, wha role for Washingon. [4] Code Federal Regulaions. Tile 49- Transporaion Secion 567.4 Requiremen for manufacures of moor vehicle USA 14. [5] EVs word wire esla receives firs Panasonic lihium-ion baery, EVworld.com, Rerieved (). [6] Effecs of Winer on Tesla Baery Range and regen, eslai.com (14), Rerieved (15). [7] The Theoreical Analysis on he performance of a racion sysem M.M.A. Murad. Jasem. M. Al-Rajhi., Inernaional Journal of Science and Advanced Technology (ISS 2221-8383) volume 3 no. 8 Aug. 13. [8] Andrew English (14) why elecric vehicles mus cach on, Daily Telegragh, Rerieved (14). [9] The measuremen of fuel consumpion during rush hours a urban cycle in Kuwai ciy- Journal of Mechanical Engneering and Auomaion. M.M.A. Murad, Jasem. M. Al-Rajhi. [] Fuel consumpion raing(w.w.w.oee.nrcan.gc.calransporaio n/ fuel raings/ raings-search, cfmar=8) Governmen of Canada. January 11. [11] Fuel consumpion raings- Governmen of Canada. January 11. Rerieved 8 June 11. [12] ew European Driving Cycle-From Wikipedia, he free encyclopedia. [13] Developmen of speed correcion cycle. EPA Documen MG.SPD.001, sierra Research 6 June 1997. [14] Gas prices oohigh- 05/0826 PoL 1-9.